Language, Identity and Cultural Difference Essay

According to Hall (1997a), enunciation theories suggest that even though we may talk of ourselves from our experiences, the person who speaks and the subject being spoken of are never identical. Identity in this regard is to be conceived as a production which is never complete- â€Å"always in process, and always constituted within, not outside, representation†- (Hall, 1997a) as opposed to viewing it as a complete fact which is then represented by the new cultural practices. However, this view shakes the legitimacy and authority upon which the term cultural identity bases its claim. There are two ways in which cultural identity can be thought of. The first view sees it in terms of a single shared culture, some kind of a collective ‘one true self’ that is hiding inside many other more artificially imposed selves that people with a shared history and ancestry hold in common (Hall, 1997b). Within this view of description of cultural identity, our cultural identities mirrors those historical experiences that we hold in common and the shared cultural codes which offer us as a people, a stable, immutable and continuous frames of reference and meaning, under the shifting classes and fluctuations of our actual history (Hall, 1997a). Singapore was envisioned by her leaders as a multiethnic society in which the constituent ethnic groups shared participation in common institutions while at the same time retaining their distinct languages, customs and religions. The ethnic categories represented self-evident, natural groups that would continue their existence into the indefinite future. Singaporean identity therefore implies being an Indian, a Chinese, or a Malay but in relation to other groups. This model of ethnicity demands the denial of important internal variations for each ethnic group and the recognition of differences between the categories (Tsui & Tollefson, 2007). The second view of cultural identity recognizes that there are similarities and important differences which make up what we really are. We cannot persistently refer with exactness to one experience and one identity without recognizing the other dimension. This other dimension represents the rifts and discontinuities that comprise cultural uniqueness. In this second sense, cultural identity is viewed as an issue of both â€Å"becoming† and â€Å"being†, something that belongs to the future as much as it belongs to the past. Cultural identities in this regard have histories and therefore changes constantly. In other words, cultural identities are subject to the uninterrupted play of history, culture and power (Hall, 1997a). Identity is the name given to the different ways we are placed, and put ourselves within the tale of the past. This second conception of cultural identity is more disturbing and less familiar. How can the formation of identity be understood if does not proceed from a straight line or a fixed origin? The Singaporean identity can be thought of as composed of two vectors that operate simultaneously. These are the vectors of rift and difference, and similarity and continuity. The Singaporean identity can be seen with regard to the relationship between the two vectors.   Similarity and continuity brings to fore the realization that it is the experience of fundamental discontinuity that the Indians, Malays and Chinese share and among these are immigration, colonization and Asian origin. It is therefore interesting to look at how the concept of identity, language and cultural differences were created and how these concepts are related within the context of Singapore. The analysis herein presented will be based in Hall’s view of the link between language, identity and cultural difference. Relationship between Language, Identity and Cultural Difference The relationship between language, culture and identity has emerged to be a hotly contested topic in social sciences. The questions that mainly arise concern the apparent difference between cultural and ethnic identity. Are these types of identities similar or should they be differentiated conceptually. Various scholars hold varying views on the role of language in the definition of one’s identity. A major question that one may be compelled to ask is whether a culture or ethnic group can be considered to be unique if it does not have its own language or in the least its own rendition of a common tongue. Cultural identity is universal whether it is expressed with regard to humanity or otherwise since people from every part of the world are conscious of some kind of specificity that sets them apart from others. In contrast, ethnic identity only appear to take place within complex societies when it seems functional to separate individuals into categories founded upon something other than age, gender or occupation. Ethnicity is associated with cultural identity since one must make reference to cultural, linguistic or religious particularities in order to categorize individuals. According to Hall (1997b), culture is produced by representation. Culture concerns shared meaning and the medium through which we make sense out of things is through the use of language. It is through language that meaning is produced and exchanged. The only mechanism of sharing meaning is through a common access to language. In this regard, language is fundamental to meaning and culture and has always been conceived as the major bank of cultural values and meanings. However, one may be compelled to ask how meaning is constructed through language. According to Hall (1997b), language constructs meaning via its operation as a representational system. Language is one of the mechanisms through which ideas, thoughts and feelings are represented in culture. In this regard, representation through language is fundamental to the processes through which meaning is produced. Our sense of identity is derived from meaning and therefore meaning is linked with questions about how we use culture to define and maintain identity and difference within and between groups. In every social and personal relationship in which we participate, meaning is constantly being produced. Meaning is also produced through our expression in and consumption of relevant cultural materials. Our conducts and practices are also regulated and organized by meaning which help in the setting of rules, norms and conventions upon which social life is ordered and governed. The question of identity therefore emerges in relation to various other divergent moments or practices within the cultural circuits; in our construction of identity and the defining of difference, in the production and consumption and in the regulation of social conduct. In all these instances, language is one of the most important medium through which we produce and circulate meaning.

Abnormal Psychology Assignment

The textbook also explains four mechanisms that help people deal with adversity and foster a good mental health and defines good mental health as the presence of cognitive, social and emotional functioning. Early Childhood From the individual level, the textbook gives several examples of risk factors. Was lucky enough to not have any behavioral, socio-emotional, cognitive or biological risk factors that were present in the earlier years Of my life that I am aware of. However, my younger brother was diagnosed with a learning disability.Although it didn't affect me directly, some of my friends teased my brother and in turn, affected the way thought about myself in relation to my family. In the family domain, I was raised in a dual-parent household. The textbook states that a single parent household is a risk factor. My parents rarely fought and they have a loving relationship to this day. I would like to say that this is a protective factor. Having the support of both of my parents rea lly fostered my self-esteem and my sense of well-being. This became very evident in middle school when I struggled with my friendships.My parents were always there to support me. When I was very young, my parents were unemployed for a few years. As a protective factor to offset the employment and no income, my parents were able to monitor me and I excelled in my academics for most of my childhood. My parents immigrated to Canada one year before I was born. They were fearful of what would happen when China was given back control of Hong Kong in 1 997, which is where my parents are from. Therefore, they came to Canada to avoid the politics and start a new life for themselves.Coming to a democratic country was a big change for them as well as any children they were going to have. I have grown up without the same pressures and rules that may have been imposed if my parents had stayed in Hong Kong. My self-esteem may have been hindered drastically and may have been more afraid to speak o ut on certain matters because of the way the government is run. The fact that politics is no longer a worry in my early childhood significantly reduced the amount of stress I would've felt had been living my parents' home city.The textbook mentions democracy as an example of a protective factor in the socio- political level. The school system in Hong Kong is also much more stressing on a child even from an early age. Everyone is very competitive in Hong Kong and I'm not sure that would have enjoyed growing up in that type of environment as the pressures to succeed would have been a lot to handle. Was able to develop in a relatively low-stress environment until high school. Mid-childhood Throughout elementary school, I had many friends, which created a great environment for me to develop the skills that were necessary to my social functioning.A presence of social, cognitive and emotional functioning are factors that are part of the definition of mental health. As I moved to middle sc hool, maintained a small group of friends who were positive role models or me. Through the later years however, I was unable to connect with my peers. Some of them had different interests and some even went as far to abuse substances. This particular risk factor is delinquent peers. I never partook in these interests because never needed to turn to substance abuse to get through school and I wasn't interested in the same things as everyone else was.I enjoyed learning and the middle school I attended fostered my cognitive functioning. Because I didn't follow the norm, another risk factor was present in my life; peer rejection. Towards the end of middle school, I ad few friends whom I could trust and was quite shy. I was bullied because of my ethnicity and also because of the fact that I came from a less wealthy background than my peers. This in turn affected my self-esteem and is a large factor in a person's mental health. Although my self-esteem around my peers was not great, I was quite confident in my cognitive and academic abilities. As given many opportunities for personal growth such as being put into a special advanced math program. This helped me lessen the impact of risk factors that I encountered in the peer and school domain. Community articulation also played a huge part in why my self-esteem was still positive. Was involved with extra-curricular outside of school, which allowed me to distance myself away from the risk factors I encountered at school. I had another group of friends could depend on for being positive role models and to foster positive peer relationships.My parents continued to monitor me because they understood that I was going through a tough time with friends in middle school. Because of these factors, they asked me if I wanted to attend the high school in my neighborhood. By moving schools, this allowed me to completely start over and virtually eliminate the risk factors that came with attending this middle school. Early adolescen ce During high school, I was able to step out of my comfort zone and develop resilience to many risk factors because I had found new friends who fostered a positive school climate and positive peer relations.My friends in high school actually cared about school and would encourage me to do my best. They also got me involved in many extra-curricular at school. We connected on many different levels and I was able to enjoy life more without having the terrors that had in middle school and improve upon my social connections. The ability to enjoy life and social connections are two positive mental health components that are defined by the Canadian population Health Initiative (pig. 473).Towards the end of high school, my grandmother was diagnosed with mild depression after my grandfather committed suicide. Both of them were struggling with a mental illness. My entire family was unaware of the mental health condition that my grandfather was in after he was diagnosed with cancer. This put huge stress on my mothers mental lath as well as my own as care dearly for both my grandmother and my grandfather. Currently, grandmothers mental illness is another risk factor that is present in my life. My grandmother is incapable of taking care of herself due to her severe arthritis.My mother took on the administrative work to get her moved to a care facility but our entire family puts a lot of time and energy to see her. This has put stress on everyone including myself. She does not show many signs of improvement and still struggles With mild depression. Current When came to university, I moved out of my parents' home and into a accidence. My apartment mates were my peers at the time. They were delinquent peers and I mostly kept to myself at home. I like to keep things quite neat and the state of our apartment was too much for me to handle.My apartment mates would come home late at night, which would often disrupt my sleep due to the high noise level. To offset the amount Of str ess I experienced, I turned to community involvement. Got involved with Foot Patrol, Winter Carnival and the Chinese Student Association. This allowed me to distance myself from the risk factor because I would be spending less time t home. All the extra curricular involvement enhanced my self-esteem and self-efficacy and had the opportunity to develop myself as a person and grow.The friends met through community involvement had great future aspirations and would always encourage me to plan for my future. This is another protective factor. At the time, I was still unsure of what stream of business wanted to focus on. The uncertainty was a major stress factor in my life but I recently decided to pursue marketing. Next 5 Years will have student loans to pay off which is a significant stress. Also face he task to find a place of my own because I will be moving out.I'll have to move to a different neighborhood and make new connections with the people around me as well as the peers that h ope to meet when start working at a full-time job. My parents have started saving for their retirement and that puts enormous stress on my mental health because they will no longer be able to support me. This is a huge change as for most of my life as I was used to being cared for financially. To offset these stress, I will continue to participate as an active member in the community. This will help o strengthen my relationships with my peers and continue to provide me opportunities for growth.Community participation is a very important part of my life and I hope it will continue to be. It develops a person's cognitive, social and emotional functionality, which in turn leads back to a positive mental health. The personal growth that I've seen in myself gives me a positive outlook on my mental health and life in general. In order to offset the stress that will encounter, I will maintain my current friendships and attempt to create new ones. Will also maintain the strong family legisl ations have developed over the past few years.

Chanel Analysis Swot, 6 P’s

GAC002 Assessment Event 4: Academic Reseacher Essay| The Fast Food Industry| | | Student’s Name: Alexandra Student ID: QING21632 Teacher: Lynken Ghose Due Date: August 27th 2012 Word Count: 1162 Word Count: 979 Student’s Name: Alexandra Student ID: QING21632 Teacher: Lynken Ghose Due Date: August 27th 2012 Word Count: 1162 Word Count: 979 Question: Define the idea of â€Å"fast food†. How has fast food affected the food industry in China? Has it become a more prevalent or less prevalent force? Would you say its impact has been positive or negative? Please do not offer just a simplistic answer such as – â€Å"positive† or â€Å"negative†.Offer specific reasons including ethical implications, economic implications, and health effect etc. of fast food. With the pace of life speeding up, people increasingly depend on fast food. Many people prefer to eat fast food rather than cook by themselves, because fast food is more convenient and time â€⠀œ saving. In my opinion, people should not depend on fast food too much because fast food’s impact has been negative, as fast food has endangered people’s health, family life, traditional culture, and has even caused ecological change to the environment.Firstly, the safety of fast food ingredients is really worrisome. During the last several years, more and more safety problems of fast food have been exposed by the media. For example, many restaurants add too many preservatives to fast food in order to maintain the freshness of food, or they added varying additives to enrich the taste and look of food. It is really bad for people’s health and many kinds of preservatives and additives are subject to blastomogens, such as tonyred, leavening agent, benzoyl peroxide, and so on.In addition, in order to reduce cost, more and more restaurants choose to use inferior seasonings. For example, industrial salt instead of edible salt is used as seasoning. It is known to us all that the main ingredient of industrial salt is nitrite which is a kind of poisonous and harmful substance and its lethal dose is only 3g (E Hyytia, S Eerola, S Hielm & H Korkeala 1997). Furthermore, some fast food which is subject to acid-forming diet and will lead to the souring of body fluid if people depend on them overly (Cheng, Tsung O. 2004).Then, calcium, phosphorus, magnesium and some other elements in our bodies will be neutralized, so more and more children are suffering rickets and other kinds of diseases which are caused by a lack of calcium. Secondly, fast food reduces communication time among family members, so that intimacy is affected. Dinner time is supposed to be a good chance for family members to chat and communicate with each other. After a tiring day of school and the company, children and parents are eager to exchange something interesting or exciting. Not only the time in table, even preparation time and dish washing time should be spent together.Thatâ₠¬â„¢s how family love and happiness is developed. However, with the development of fast food, dinner time has changed into pizza time, coke time and hamburger time. You only need to make a call. They would deliver what you order in fifteen minutes without anytime to enjoy taste of home – made food, the faithful fast food lovers finish the dinner as soon as possible and then take out the remote control, watching football games or soap operas. No wonder parents often complain about strange feelings with children. Thirdly, fast food, especially western fast food, has a negative impact on local traditional culture (Goodman, Peter S. 004). There is no doubt that diet is one part of traditional culture. Take China for example. China is an agricultural country, so Chinese people have always regarded diet as a very important part of life. Chinese people not only care about nutrition, but also love good taste and appearance. As for cooking methods, we can boil, steam, stir, stew and s moke. More importantly, we love quality time when we are sitting with family or friends, chatting and laughing. However, when KFC opened its first restaurant in Beijing on November 12th 1987, traditional culture began to decline.Later, McDonald’s, Pizza Hut, Burger King, Subway entered to China one by one, and they changed the younger generations thinking about food. At the very beginning, Chinese people entered KFC because of curiosity. Later the young generation was attracted by fast food culture. They even regard it as a fashion. The traditional dietary culture can’t have a good development without the support of younger generation. Fourthly, fast food industry is harmful to the environment. The main ingredient of western fast food is meat, including pork, beef and chicken.To produce one pound of meat one needs five pounds of grains. The quantity of water used in animal farming is eight times that of in plant farming. That is to say producing meat uses more resource s. When the globe is having more and more population, resources, such as water, soil and grain, are valuable. We should eat less meat and refuse fast food to protect environment. However, it doesn’t mean that fast food has no advantages. Eating fast food is helpful for us to work efficiently, so, so many people still choose eating fast food as often as they can.In addition, many people, especially young people, regard eating in western fast food restaurant as a kind of symbol of taste. Since young people don’t have much money, they can’t afford fancy restaurants. When they eat out, they have to choose between small Chinese restaurants and western fast food restaurants. When they enter these small restaurants, they often see greasy floor and tables, smell smoking air and hear noisy talking. But things are quite different in western fast food restaurants. You will be served with clean floor, warm smile and peaceful environment.That’s why young people would choose to meet friends, review their lesson and surf the Internet there. Because of these factors, western fast food restaurants have become a symbol of style and class. However, their idea goes against the purpose of fast food. Fast food is supposed to save time, but when they are surfing the Internet or chatting with friends, they are wasting too much time. Reference Cheng, Tsung O. 2004. Fast food, automobiles, television, and obesity epidemic in Chinese children. International Journal of Cardiology. 98 (1): 173-174. Goodman, Peter S. 2004.Fast Food Takes a Bite Out of Chinese Culture. Washington Post, December 26. Patricia M Anderson & Xiaohong He (1999), Culture and the Fast – Food Marketing Mix in the People’s Republic of China and the USA: Implication for Research and Marketing: Vol 11. Journal of International Consumer Marketing 1: 77 – 95. Available at: http://www. tandfonline. com/doi/abs/10. 1300/J046v11n01_06 E Hyytia, S Eerola, S Hielm & H Korkeala (1997), Sodium nitrite and potassium nitrate in control of nonproteolytic Clostridium botulinum outgrowth and toxigenesis in vacuum-packed cold-smoked rainbow trout. Online]. Available at: http://journals. indexcopernicus. com/abstracted. php? icid=756375 S Rice, E J McAllister and N V Dhurandhar (2007), International Journal of obesity Fast food: friendly? [Online]. Available at: http://www. nature. com/ijo/journal/v31/n6/abs/0803580a. html Rasooly, Avraham and Herold, Keith E (2006), Biosensors for the Analysis of Food- and Waterborne Pathogens and Their Toxins[Online]. Available at: http://www. ingentaconnect. com/content/aoac/jaoac/2006/00000089/00000003/art00034#aff_2

Consumer behaviour in Cambodia Dissertation Example | Topics and Well Written Essays - 6250 words

Consumer behaviour in Cambodia - Dissertation Example This section will comprise the justification and description of the research methods that are to be put into practise in order to determine the consuming behaviour in Cambodia. The methods that will be adopted have been explained in detail so that a suitable pathway can be determined. The chapter will shed light on the research design, the methods and the philosophical approaches of the study. The chapter then proceeds to highlight the sampling method and the sample size of the study. The target population or the intended participants who will be approached will be also highlighted. In addition, this chapter will also emphasize on the process of data collection and how the collected data will be analysed in the subsequent section. Lastly, the study will state the ethical issues associated with the study and the limitation of the study. 3.2 Research Philosophy It is necessary for a researcher to make certain assumptions regarding the nature of reality which is to be studies (Daniel, 2 010). Apart from that, assumptions are also made about the knowledge produced and the research perspective. Figure 1 The figure above summarizes the approaches that can be used by the researchers in a research study. The approaches have been summarized in the form of epistemology, ontology, theory, perspective, techniques and methods. Each of these different approaches entails to a different way of performing the research. In general there are two research philosophies namely interpretivists and positivist (Blaxter, Hughes and Tight, 2006; Guba and Lincoln, 2005). Positivism is a philosophy of research which is based on the view that sociology must use the natural methods (Tobin and Joseph, 2006). However, that does not mean only use of experiments as there are several problems associated with experiments. The biggest one comes in the form of ethical violations. The researcher who believes in positivist philosophy believes that research works must be conducted with the help of quant itative methods. They principally aim to measure the social structures (Mehrens and Lehmann, 1987). On the other hand, interpretivists or anti positivists takes the other way round. According to their point of view, human being perceives and reflects on that basis and scientific studies are not appropriate for the study of society. They also believe that unlike objectives human being has the ability to alter their behaviour. Hence, the inference is that in order to understand the social action, it is necessary to understand the meaning and reason people perceive about the environment around them (Abbott, 2010; Connaway and Powell, 2010; Gordon, 2007; Snieder and Larner, 2009; Wilson, 2010). Another important finding of the study is that researchers who follows interpretivism philosophy believes that social research must be conducted with the help of qualitative method (Saunders, Lewis and Thornhill, 2009; Browne, 2006). This study seeks to investigate the consumer behaviour pattern of Cambodia and hence it clearly

Species Divergence Essay Example | Topics and Well Written Essays - 1000 words

Species Divergence - Essay Example physiology, the mode of interaction with its environment, nutrition regime, etc. While evolutionist ideas may be discerned in several pre-modern scholars’ ruminations, it was only with the advent of the 18th century Enlightenment that modern evolutionary theories formed, with that of Charles Darwin soon taking the pre-eminent place among them. The formation of currently mainstream version of evolutionary biology was immensely helped by the respective advances in the fields of genetics and molecular biology, which helped define the organic basis for evolutionary processes. From a biological organization point of view, evolution proceeds on a species level, as individuals comprising a species do not themselves evolve over the course of their lifespan. However, the results of their interaction with the environment enable the accumulation of new heritable responses within their genotype structures, giving rise to a process of natural selection. The latter, in its turn, conditions the changes in the species’ phenotype (i.e. the complex of biological features). Natural selection may be properly defined as a gradual process of genetic variation whereby the individuals with most favorable gene combinations are more frequently able to transplant their genes to subsequent generations of a species, so that their descendants will define the face of their species. While natural selection process is individual, being transmitted across a species only indirectly, it is genotype of a species as a whole that it impacts on, so that heritable changes in those individuals’ genotypes that are favored by natural selection are spread to the subsequent generations of a species as a whole. The mechanisms of natural selection are varied; however, some of them may be assigned more prominent roles in its perpetration. Of those, ecological selection, with an emphasis on fitting with one’s biological environment, and sexual selection, with an individual’s fecundity and ability to find prospective sexual partners as a key factor, may be considered the primary ones. In turn, these mechanisms may be sub-divided into more specific methods of selection, with, e.g., ecological selection encompassing the mechanisms of intraspecies competition, kin selection, etc., and sexual selection including those of intrasexual selection, intersexual selection (sexual dimorphism), etc. b. Evidence for biological evolution is manifold and comprises the number of data from different scientific disciplines. Within the context of this essay, five types of this evidence will be examined. Plate tectonics. The discovery of the movements of plates in the 20th century laid to rest the notion of unchangeable nature of Earth’s tectonics, contributing to an idea of nature’s propensity for change. On a more specific level, Charles Lyell’s studies on the impact of climatological and geological changes on the distribution of species, with specific emphasis on extinct flora, led the researchers to conclude that movements of large land masses lead to conversion of climates, which meant that animal and plant species had to be dynamic entities, the spatial distribution whereof changes in accordance with the changes of topography brought about by geological agents. Consequently, the changes in floras and faunas were decisively connected with the corresponding shifts of land masses, contributing to the development of an idea of ecological selection. Biogeography. The research in the connection between plate tectonics and changes in life on Earth that was referred to above has been directly connected with the research in the field of biogeography. Such scientists as Edward Forbes, Wallace and Willer Matthew conducted an extensive research in the

Describe types of feedback and determine the effects of circuit Lab Report

Describe types of feedback and determine the effects of circuit performance when feedback is applied,Describe the circuit conditions and the methods used to achieve sinusoidal oscillation - Lab Report Example The two types of amplifier are the positive and the negative feedback. The two differ in terms of whether the signal is described as being in phase or out of phase with the input signal. The two types of feedback can also be referred to as regenerative or direct feedbacks. Regenerative feedback or negative feedback occurs whenever a signal is said to be 180 degrees out of phase to the input signal (Musrt 89). A widely cited, negative feedback is appropriate since it helps in creating a practical circuit given that it can create rates and gains. It can also be used in making circuits stable, as well as self-creating and it has an output that can characteristically create equilibrium condition. In an op-amp, a negative feedback is used for purposes of creating a corrective mechanism (Musrt 67). Moreover, it limits the amplifier’s input signal hence improving the fidelity of an amplifier. By and large, it increases the frequency response of any given amplifier through preventing the decreasing in the gain of an amplifier. During the application of an amplifier, the feedback signal reduces with the increasing input signal (Musrt 76). On the other hand, in the positive feedback, the voltage or current feedback is often applied for purposes of increasing the input voltage (Musrt 47). When a positive feedback is applied in an inverting signal circuit, a portion of an output signal is fed back to the input. It is worth noting lacking a positive feedback in any circuit causes a slowdown in the detectors of the open loop. Positive feedback can lead to an increase in the amplifier gain. More often than not, feedback is used in electronic circuits for various reasons. First, circuit characteristics can be controlled and made independent of wide variations in most of the active device parameters (Musrt 34). Second, using feedback, it is possible to make circuit characteristics relatively independent of

English Education Essay Example | Topics and Well Written Essays - 1000 words

English Education - Essay Example An interesting dimension to this trend in education is how students choose their schools. One would find, for instance, that parents take a greater role in their children’s schooling, especially in regard to university and skills education, in their desire for a better life and chances for their children. For example, Doria, (2005) talked about the case of Australia: A â€Å"factor that influences students to study in Australia is that the country is comparatively safe, it has a clean environment, and living here is affordable.† (20) Students are swayed by attractive university marketing, say, one that promotes the high quality of education and the relative appearance of the school campuses. Scholarship offerings, which the U.S.A. is known for, is also important factor in the students’ choices of schools. (Doria 2005, 9- 20) Another issue in studying abroad concerns immigration opportunities. For parents, if their children study, say, in Australia, there is a possibility of obtaining Australian citizenship for all families and that, in itself, is a worthy return for the investment. In addition, many students look for career opportunities by studying abroad where they can develop their mental abilities, cultural perspective and in learning another language. Some of them want to get away from restrictive customs (Doria 2005, 19). The result of this new phenomenon in education is that overseas students are forcing changes in the curricula of universities by requiring emphasis on the methodology of teaching, special programmes and also result in confronting the slowing down of communication classes due to language-skill and cultural barriers. In preserving the quality of education including improving the standard of English courses, universities have to focus on developing teacher abilities and changing styles of educational

Parkinsonism and other Extrapyramidal Diseases Essay

Parkinsonism and other Extrapyramidal Diseases - Essay Example In essence, I did the best I could with what I was provided. The normal functions of the human basal ganglia have largely been deduced from the study of functional problems associated with destructive or irritative lesions. To a large degree, the deficits are in motor function and, therefore, the extrapyramidal system and basal ganglia have been associated with movement disorders. Important interconnections of the basal ganglia are the nigrostriatal pathway, and the ansa and fasciculus lenticularis, and the fasciculus thalamicus, which interconnect the globus pallidus and the ventral lateral and ventral anterior (VL-VA) nuclei of the thalamusand the VL-VA thalamocortical fibers, the subthalamopallidal pathway, striatopallidal fibers, and cerebellothalamic interconnections Parkinson's disease, first described by James Parkinson in 1817, is one of the most important disabling illnesses of later life. It is estimated to affect 1% of 70-year-olds, but is also seen in younger people, with 10% of cases occurring before the age of 50. Parkinson's disease is one of the most common neurodegenerative diseases, but estimating its incidence and prevalence is problematic, since there is no 'in-life' marker for idiopathic Parkinson's disease; estimates of the annual incidence of Parkinson's disease are in the range of 4 to 20 per 100000 individuals. A widely accepted figure for the prevalence of Parkinson's disease is approximately 200 per 100,000 populations. In the UK, there are approximately 120,000 to 130,000 diagnosed cases, but there may be many more that remain undiagnosed. In the USA, it is estimated that between 750,000 and 1.5 million people have the disease. ( Ref) Age, Sex, and Ethnicity Both the incidence and prevalence of Parkinson's disease increase with age, and the prevalence may be as high as 1 in 50 for patients over the age of 80 years. Men are 1.5 times more likely than women to develop the condition are. Hospital-based studies have suggested that Parkinson's disease is less common in the black population. Pathology The main pathological feature of Parkinson's disease is the degeneration of neuromelanin-containing neurons in the pars compacta of the substantia nigra. Examination with the naked eye reveals pallor of this area, which is confirmed microscopically by a marked decrease in the number of neuromelanin-containing cells and the presence of Lewy bodies in the remaining nigral neurons. Degeneration of pigmented neurons in the brainstem is not limited to the nigra but extends to the locus ceruleus and the dorsal motor nucleus of the vagus. Neuronal Degeneration The cause of neuronal degeneration in Parkinson's disease is unknown. The susceptible neurons are located in astroglial-poor regions such as the ventral tier. Glia may offer neuroprotection by providing neurotrophic factors that prevent cell death. Several hypotheses for neuronal degeneration have been proposed, including: oxidative stress, induced by dopamine metabolism or other factors defective mitochondrial energy metabolism excitotoxin- and xenobiotic-related cell death programmed cell death (apoptosis) to the medial

World civilizations in eighteenth century Term Paper

World civilizations in eighteenth century - Term Paper Example Therefore the workforce required for agriculture decreased and this led to a migration of this workforce to the field of industry, which in turn led to the industrial revolution. Before the industrial revolution, goods were manufactured using basic hand tools or machines in homes. The introduction of powered machinery that could mass produce goods in factories, led to the need for new markets for these goods, as well as new means of transportation to carry them. Mechanization of the textile industry coupled with improved techniques for making iron, and the invention of the steam engine, that revolutionized the transport system, in turn led to improved systems of trade and finance. Engines and machines that could do away with the physical labor of man, besides cutting down the time taken to accomplish it was a blessing indeed! Britain was the first to begin mechanized spinning and weaving because she was blessed with the moist weather conditions that helped in this industry. Besides, the fast moving streams supplied hydropower for these mills. As the economy moved from manual to machine based manufacturing, the manufacturing time was slashed and new markets were needed for these goods. The mechanization of spinning was followed in quick succession by the development of techniques for making iron. The introduction of the steam engine was the final triumph that revolutionized the transport system and increased the use of refined coal to power these steam engines. Britain being an island nation, her ports enabled her to trade in these goods and at this time Britain indeed ruled the waves. The efforts of British entrepreneurs were rewarded due to the fact that they had a large and ready market for their goods. Growing trade and commerce in... This paper shows that the thinkers wanted to bring about changes in society through the promotion of education and scientific thinking. In some European countries, a system of government called â€Å"Enlightened Despotism† came into being. Later, we are shown the need to feed the growing population, which led to a transformation in agricultural systems like improved machinery, scientific methods of breeding and introduction of new crops and crop rotation. Throughout the paper, we are given more and more information on the introduction of powered machinery that could mass produce goods in factories, led to the need for new markets for these goods, as well as new means of transportation to carry them. This paper also focuses on trade. Trade systems were dominated by those who held sway over the seas, and expansion of trade depended on the acquisition of colonies and the superiority of naval power. Swiftly from trade, the paper talks about the banking. For example, the Bank of En gland that worked as a government bank as well as a commercial operation, led to the setting up of a number of private banks throughout the country. In conclusion, we see that this industrial revolution transformed the lives of people in every stratum of British, European and American society. Building on the ideas of enlightenment of thinkers such as Voltaire and Rousseau, the eighteenth century saw the overthrow of despotic rule through the American and French revolutions and sowed the seeds of many more such upheavals in the centuries that followed.

Botticelli's spring and Michelangelo's creation of adam Essay

Botticelli's spring and Michelangelo's creation of adam - Essay Example Botticelli’s Primavera and the Birth of Venus are mythological paintings where storyline is seriously pursued with due respect to its mythological lineage. Goddess Venus is depicted as Virgin Mary in unique style. Michelangelo Buonarotti 1475-1564 was the most gifted painter of the Renaissance times, outshining other artists in fine art, sculptor, and architecture. The Creation of Adam – is central to his Sistine Chapel frescoes . Michelangelo’s faith in the outward beauty is reinforced through the Creation of Adam. This can be seen in his early poetry as well where he links beauty to divinity. The Creation of Adam is a wonder in art in the sense that he has made the touch of the Divine hand central to the picture and symbol of the power of the Creator. Michelangelo was responsible for transforming the history of culture. As Wolfff\lin in Classic Art, Trans. 1952 comments: â€Å"If any one man may be held responsible for major changes in the history of culture, that man was Michelangelo, who brought about the generalized heroic style and caused place and time to be disregarded’(Stokes, 1955: 106). The delineation of Sixteenth century dress and architecture was exaggerated not at the cost of characterization but to provide dignity in presentation, it was enlarged as ‘its flowers grew from the old soil, but they waxed bigger’(Stokes, 1955: 106). It was a period of resurgence of interest in the art and culture of Greece and Rome by European civilizations. It was a reaction to the rigidity of feudalism and Church of the medieval period where individual interests were subservient to society, ruled by feudal lords for material needs and Church for spiritual aspirations. The Renaissance started in the creation of city states like Venice, Florence, and Milan, self-sustaining and creating Franciscan humanism. Such states provided economic means to keep both ends meet to the

Societies Essay Example | Topics and Well Written Essays - 1500 words

Societies - Essay Example It is complex play of power and dominance over the weaker defenseless sex, for superiority and satisfaction. The relationship between man and woman, and the significant role that a woman plays to keep the social and the family scene moving accounts for the hidden power with which women perform her duties regardless of time and age, in 20th century Muslim society or 17th century Chinese society. Men reserved the right to betray, women remained faithful, virtuous and honorable before marriage and even after husbands death. In Alifa Rifaats collection of short stories "Distant View of Minaret" dealing with 20th century Muslim women in Egypt, the reference is to the issues related to woman's suffrage in contemporary Egypt. In the story "Distant View of Minaret" the reference in that context is to lack of privileges, rights, and gender roles and expectations facing woman. Or even simply the basic "Men being in control of woman." However, two unexpected issues are brought up in her book and both are reflected in this story. The first being sex and the second being death.(Rifaat) In this story, she describes the sexual suppression and deprivation of a young married woman. She had long forgotten her desires, needs, and urges. She had adopted a passive role not only in the family lifestyle but in the bedroom as well. "The last time she made such an attempt, so desperate was she at this critical moment that she had dug her fingernails into his back compelling him to remain inside her." ((Rifaat p. 2) The story then goes onto explains how her husband pushes her away and screams at her as though she was trying to kill him. After this failed attempt to pursue her passion she began to feel as though she was asking too much and belittled herself. It made her feel ashamed and embarrassed to even think about the act. Later in the story it points out other occasions where her husband would suppress her urges purposely. "But on each occasion, when breathlessly imploring him to continue, he would-as though purposely to deprive her-quicken his movements and bring the act to an abrupt end." (Rifaat) The act that is supposed to involve two people in passion suddenly dissolves to one.(Rifaat) In his book "The Death of Woman Wang" Jonathan D. Spence projects the life of the rural China in seventeenth century, when the ideologies of Confucius was very strong on the society. The story is about a woman, Wang, who has an illicit affair with a man and she runs away with him. The adultery is dealt very harshly in Chinese society. The husband had the right to punish, penalize or even kill the man as well as the wife. Wang is finally tracked own and returned to her husband, and is finally killed in her own bed by her husband for the disgrace. The projection of the position and the role of the woman in the Chinese society at that time is illustrated revealing the status and position of the woman in the Chinese Confucian society. The story of is the central essence of the book, though it is revealed much later in the book, the picture which is revealed is of village life in T'an-ch'eng, the people, society, their everyday life and interactions between the people in the community. The role of marriage and the transformation which a woman goes through to keep her marriage is one of the key issues emphasized in both the stories

Colonialism and Latin America Essay Example for Free

Colonialism and Latin America Essay Eduardo Galeano is a passionate journalist and writer, a man that has put this passion into writing about the lost or often overlooked histories of Latin and South Americas. In one of his acclaimed books, Las venas abiertas de America Latina/Open Veins of Latin America, he looks at the history of exploitation in this place from early European explorers to current United States and European endeavors. In this paper using three examples from Open Veins of Latin America by Eduardo Galeano, will show how Latin America has developed a dependency on foreign entities. Latin America was mostly untouched by the European world until 1492, when the Spanish where looking for a cheaper way to obtain the goods from the Exotic East. Galeano even goes on to speculate that even earlier explorers could have visited thus creating the religions and gods that the native tribes worshipped (pg. 17). These Spanish explorers came looking for new goods and spices, and when they saw that these natives had bits of metal upon them and inquired after them discovered that gold and silver were in abundance here. Thus began the Spanish Conquistadors reign begin in Latin America, though out numbered 10 to 1, the Spanish steadily moved out. The technology gaps between these two worlds was astounding, as Columbus earlier noted, â€Å"They knew nothing of swords, and when these were shown to them they grasped the sharp edges and cut themselves. † Along with gunpowder, full metal armor, and most importantly horses the Spanish were able to decimate and terrorize most opposing forces that they encountered. â€Å"The conquests shattered the foundations of these civilizations† (pg.43), afterwards almost every major native city and been sacked and looted along with the natives being indentured or killed. The mines that were established created the greatest displacement of the native people; it forced them into grueling labor and destroyed the agricultural communities. These early conquests helped lay the groundwork for the future exploitation of this region. Gold and silver were the main motivating forces for the Conquest, but many other goods have developed within this region. Foremost of these goods was sugar, in fact it was such suitable terrain that it proved to be a â€Å"white gold. † The early sugar plantations were pure profit for the Spanish lords, with legions of African and Native slaves and soil ideal for sugar cane. This new agriculture and overseers helped contribute to the already old agriculture downfall. Forests were felled and other crops were dismissed as unnecessary, sugar became the only crop that mattered. These plantations developed into what we know today in Latin America as the latifundio, which has been meticulously honed into a system that allows for the highest profits to the owners but hardly adequate conditions for its workers. â€Å"The latifundio as we know it has been sufficiently mechanized to multiply the labor surplus, and thus enjoys an ample reserve of cheap hands. It no longer depends on the importations of African slaves or on the encomienda of Indians; it merely needs to pay ridiculously low or in-kind wages, or to obtain labor for nothing in return for the laborer’s under of a minute piece of land. † (pg. 60) This system created was so effective at siphoning the natural resources of the region that its growth into areas can be documented by the destroyed land and displaced populace that it leaves behind. Galeano states, â€Å"And this has not been the role of sugar alone: the story has been the same with cacao, cotton, rubber, coffee and fruits† (pg. 61). With the creation of this system within Latin America, it became ripe for foreign business interests to produce their product in this place. With the abundance of common resources available for cheap and with huge potential for a business owner to create huge profits, Latin America was directly and indirectly was given host to many business ventures from Dutch, French, English and U. S. industry. Businesses that invested into these ventures loved the model, land was acquired with earnest and more plantations were created with their overseers working for the new companies. Now all these companies could obtain a bulk product for little to no cost to them, and should you happen to own the transportation for bringing the product to its destination only created more. Investors grew rich and enjoyed their success at making double profits, though workers were not so happy. Unrest has become a staple of the Latin America countries, and unfortunately it is usually painted by our governments as the opposite of what is occurring. To begin most Latin American countries are under a Dictatorship, where the military has absolute power and the only thing with more influence is the businesses that want to keep their labor cheap. Foreign entities train these dictators then give them the money and goods they require to help maintain the goals that the businesses request of them. Most unrest that is documented is the people of these regions rising up against these Dictators to install someone for the people, but it usually doesn’t last long as foreign interest is already setting up the next player for their scheme. Latin America once boasted an ancient civilization with brilliant people; astronomers, builders, leaders, but now is governed by what product is most in demand. These people have had foreign parties that have been molding the way they live and function for over 500 years. Even know as we campaign to help them we can’t begin to grasp that these people need more than foreign interests to stop exploiting them, they need it to change their whole way of life. It’s a double edged sword, for there shall always be a party that enters the system that is only focused on its own needs rather than the needs of the people. The world has so deeply ingrained itself in the history and creation of the crutch that Latin America lives off of and if we should take that crutch away, they still won’t be able to walk, but if we show them how to do it on their own and let them govern themselves and teach them. Maybe they’ll be able to walk for themselves someday. Work Cited Galeano, E. H. (1997). Open veins of Latin America: five centuries of the pillage of a continent (25th anniversary ed. ). New York: Monthly Review Press.

Performance Appraisal Methods On Psychological Contract Management Essay

Performance Appraisal Methods On Psychological Contract Management Essay The purpose of this dissertation is to investigate the impact of performance appraisal methods on psychological contract between employer and employee in UK retail sector ( Iceland food ltd. ). The author will attempt to achieve this by focusing on importance of performance appraisal methods in improving motivation and performance of the employees and by ascertaining whether there is clear understanding of the term of psychological contract involved in performance appraisal meeting. The UK retail market is set to increase in size by 15% over the next five years, taking its value to just over  £312bn (UK Retail Futures 2011: Sector Summary, Data monitor). However this represents a slowing down of annual growth and with operating costs and the cost of credit set to rise, the retail sector faces challenging times. The retail culture is commercially driven and as such there is pressure to perform. Working in retail is hard work and the dynamic nature of the business requires a flexible attitude. Working in a shop is very likely to involve working weekends and late nights. Work-life balance could be a very significant issue for an industry that traditionally has an image of long or antisocial working hours. The retail industry employs over 3 million people (data collected March 08). This equates to 11% of the total UK workforce (UK Retail Futures 2011: Sector Summary, Data monitor). Almost 8% of the Gross Domestic Product (GDP) of the UK is generated by the retail sector. UK retail sales were approximately  £265 billion in 2007, which is larger than the combined economies of Denmark and Portugal (UK Retail Futures 2011: Sector Summary, Data monitor). The retail industry and the jobs within it are susceptible to economic and consumer trends. Today, most organisations on the major basis have some kind of performance appraisal system in place. A study conducted by Hirsh (2006) found that only a third of the HR professionals felt that the established appraisal methods have achieved theirs objectives and that most appraised exercises could not really had helped organisations to improve their performance (Hirsh, 2006 as quoted within Fletcher, 2008 p.1). Indeed, appraisal has become an emotive word because it is either done poorly or partly as the organisations keep on ignoring the values of the performance appraisal, thereby affecting the psychological contract of the individual. There are many indicators of a traumatized psychological contract; this can later be attributed to poor performance appraisal methods. Such indicators include; high turnover, low motivation, low job satisfaction (Hiltrop, 1995). According to Fletcher (2008), The unpopularity of using performance appraisal methods can be clearly seen as most organisations use the same process with different titles such as Performance Reviews, Work Planning and Review and many others. Iceland food ltd. follow this rule as the appraisal methods in place are described. Statement of Purpose The purpose of this dissertation is to investigate the impact of performance appraisal methods used on psychological contract between the employer and employee. With an aim of examining the efficiency of the techniques used to perform the appraisal system in place. The importance of the appraisal system within Iceland food ltd. will also be established. This will be initially achieved by investigating the importance of performance appraisal methods in improving the motivation and performance of the employees, and by ascertaining whether there is clear understanding of the terms of psychological contract involved in the performance appraisal meetings. It will be important to understand how these performance appraisal methods are being evaluated. The secondary research conducted on this topic, made use of a number of academic journals, articles and books related to the subject to monitor performance of appraisal techniques. The data collection procedure involves a quantitative questionnaire issued to the employees of Icelands, and a series of semi structured qualitative interviews. 1.2 The Importance of the Study The importance of the study is to understand the effect of performance appraisal on the psychological contract of the individual employee working in the retail food super stores. The method and the aim of the appraisal process is vital in giving training, motivation, confidence and job satisfaction to the employee as well as the rewards they get out of pay review. The author endeavours to find out what are the elements of the psychological contract of employee working in the retail food industry and whether or not it is affected by good or bad appraisal system used by the organisation. The primary research is conducted on the employees of the retail store to get the exact scenario of their present working conditions and their psychological contract with a focus on the performance review policy of the organisation. 1.3 Background of the company Investigated. à ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦ so thats why mums go to Iceland! Iceland began business in 1970, when Malcolm Walker opened the first store in Oswestry, Shropshire with his business partners Peter Hinchcliffe, Colin Harris, Thomas Duffin and John Apthorp investing  £30 each. This was for only one months rent at their Shropshire store. They were all still employees of Woolworths at the time, and their employment was terminated once their employer discovered their job on the side. Iceland initially specialized in loose frozen food. By 1975, there were 15+ Iceland outlets in North Wales, with the first supermarket-style outlet opening in Manchester a couple of years later. The firms head office moved to Deeside, Flintshire in 1979. Iceland was floated on the London Stock Exchange in 1984, by which stage it had 81 outlets. In 1989 Iceland bought its competitor Bejam which was some three times larger in terms of business. By January 2004, the combined chain had 760 stores throughout the United Kingdom. Finding the retail market more hostile in the late 1990s, Iceland pursued avenues for differentiation. In 1998, the firm began to focus on providing organic food and genetically modified-free food. This policy saw the company convert its entire frozen vegetable range to organic in 2000. In 1999, Iceland launched what it claimed to be the first nationwide, free, online grocery shopping service. This tied in with the rebranding of all outlets under the Iceland.co.uk. However, the rebranding exercise appears to have been quietly abandoned in the early 2000s, as the unadorned Iceland name is now used more widely, although some stores still have the Iceland.co.uk name on display. Iceland was renamed the Big Food Group in Feb 2002, and attempted a refocus on the convenience sector with a bid for Londis. Grimsey remained until the takeover and demerger of the Big Food Group by a consortium led by the Icelandic company, Baugur Group in February 2005. Since Malcolm Walkers return to the company, Iceland has reduced the workforce by 500 jobs at the Deeside Head Office, with approximately 300 jobs moved in September as a result of a relocation of a distribution warehouse from Deeside to Warrington. During July 2006, 300 workers took industrial action with the support of their union, blocking several Lorries from entering the depot. Despite this, the transfer to Warrington took place and the new warehouse was later outsourced to DHL in April 2007. In January 2009, Iceland announced that it would buy 51 stores in the UK from the failed Woolworths Group chain; three days after the final 200 Woolworths stores closed their doors for the last time. In April 2009, Iceland announced plans to close its appliance showrooms by September 2009 to concentrate on food retailing. Icelands sales for the year ended 27 March 2009 were  £2.08 billion, a 16% increase on the previous year, with net profits of  £113.7 million. Iceland is a successful and growing business, and to maintain our momentum we want to help all our people to fulfil their ambitions and realise their potential.   We take pride in our training and development, and our 2009 staff survey showed that 87% of our employees considered that they had all the training they needed to do their job well.   In addition to paying close attention to the results of these regular surveys, we conduct individual performance reviews designed to identify strengths, ambition and potential, and are strongly committed to providing opportunities for those who wish to develop their careers within Iceland.   Over 60% of our store managers have attained their positions through internal promotion. Currently Iceland is having over 750 stores through out the UK. And more than 18000 employees work within Iceland food ltd. Iceland have employees hand book that is handed over to the employees during the induction. This employees handbook is basically designed for the frontline staffs, which includes the entire details of the induction procedure, probationary period, performance appraisal, disciplinary, dress policy, dignity at work and grievance procedures and other important elements of the contract. The entire information on the Icelands was known to the author with the help of store manager of the Iceland food ltd. And from the Iceland food ltd website and staff hand book. AIM The aim of the research is to investigate the effectiveness of appraisal method on the psychological contract between the employer and employee. Objectives To examine the concept and theories related to psychological contract. To examine the concept and theories related to performance appraisal. To describe and compare performance appraisal methods used by Iceland food ltd. To critically analyse the effect of performance appraisal method on psychological contract. 1.6 Overview of the Study The dissertation will be presented in a series of the following chapters. Brief description of each chapter is written below with a diagrammatic representation (Figure 1.0 and Table 1.0 Overview of the study). Chapter 1 Introduction Chapter 2 Literature Review Chapter 3 Methodology Chapter 4 Results Chapter 6 Conclusion and Recommendation Introduction: This chapter gives the introduction to the study, covering the aim and objectives of the study. It includes the statement of purpose and the background of the company investigated. Literature Review: This chapter provides the critical analysis of all the secondary research conducted by the author on the performance appraisal, psychological contract followed by the discussion of the effects of former on latter. Methodology: This chapter explains the research aim and the research process undertaken by the author to fulfil the research questions outlined in previous chapter. It also includes the primary method conducted by the author to gather the research data. Results: This chapter includes the findings of the primary research conducted by the author. It also includes the charts and graphs that explain the findings of the research. Discussion and Analyses: This chapter includes analyses of the finding of the primary research. It also includes the comments of the interviews as well as analyse the outcome of the survey conducted by the author. Conclusion and Recommendation: This is the final chapter of the study which will give a synopsis of all the findings and cross refer it with the objectives stated in the initial chapter. It will also offer the recommendations for further research. Chapter 5 Discussion and Analyses CHAPTER 2 LITERATURE REVIEW 2.0 Introduction A literature review as defined by Fink (2005:3) is a systematic, explicit and reproducible method for identifying, evaluating and synthesising the existing body of completed and recorded work produced by researchers, scholars and practitioners (Fink 2005, p.3) AIM The aim of the research is to investigate the effectiveness of appraisal method on the psychological contract between the employer and employee. Objectives To examine the concept and theories related to psychological contract. To examine the concept and theories related to performance appraisal. To describe and compare performance appraisal methods used by Iceland food ltd. To critically analyse the effect of performance appraisal method on psychological contract. To draw conclusion and make recommendation about the effectiveness performance appraisal method on the employees of Iceland food ltd. This section therefore, attempts to review some related literature relevant to this study. Moreover this literature review seeks to justify the uniqueness of this study in the light of the works of other known scholars in the field of performance assessment strategies on the psychological contract, focusing on the performance appraisal method used by Iceland food ltd, U.K. This section is arranged into themes in line with the research objectives and questions outlined in the preceding chapter. The review will begin with the purpose of the psychological contract and the appraisal method, followed by the different types of the appraisal methods. Then the performance appraisal method used by the Iceland food ltd U.K. will be critically reviewed and how the performance appraisal affect the psychological contract between the employer and employee will be discussed. Lastly the advantages and limitations of this factor and the importance of this study will be presented. In addition, a recent view is of Conway and Briner where they define : What Psychological Contract is ? To examine the concept of the psychological contract, a review of existing definitions and research needs to be assessed. Origins of the term psychological contract derived from Argyris in the 1960s who referred to it as the implicit understanding between a group of employees and their foreman, while Schein in 1965 further developed the concept focussing on the high level relationship between the employee and the organisation (Wellin 2007). Furthermore, Kotter in 1973 (as quoted within Roehling 1997) described the psychological contract as, an implicit contract between an individual and his organisation which specifies what each expects to give and receive from each other in their relationship. (Kotter as quoted within Roehling 1997 p.210) psychological contract as, the perceptions of the two parties, employee and employer, of what their mutual obligations are towards each other (Conway and Briner (2005) as quoted within CIPD 2009) However, Rousseau (1995) (as quoted in Guerrero and Herrbach 2007) believes that the psychological contract is formulated in the minds of the employees, individual beliefs, shaped by the organisation, regarding terms of an exchange agreement between individuals and their organisation. (Rousseau (1995) as quoted within Guerrero and Herrbach 2007 p.4) Taking all that into consideration, the nature of the psychological contract can be seen as the implicit unwritten expectations and beliefs that one holds in relation to their employment relationship. These contracts can be highly subjective and what makes them binding is what they are perceived to be (Hughes and Palmer 2007). Conway and Briner (2002) state that the beliefs refer to employee perceptions of the explicit and implicit promises regarding the exchange of the employee contributions such as effort, ability and loyalty for organisational inducements such as pay, promotion and security. Moreover, Bloisi, Cook and Hunsaker (2003) supports this statement by stipulating that workers are expected to input their skills, time, effort, commitment and loyalty to the organisation in return of wages, benefits, job security, opportunity to progress their achievement, power, status and affiliations. Witte et al. (2008) clarifies further that the idea of balance is key to these mutual exchanges within this dynamic and informal contract so that the employee feels that what is offered by the organisation balances what the individual brings to the relationship. Perceived imbalance could consequently result in the perception of contract violation. The CIPD (2005) highlighted a simplified Guest model (1996) of the p sychological contract as illustrated in Figure 2.1. The influencing factors that feed into the contract include the human resource practices, organisational content and the individual characteristics of the employee. The psychological contract content can be measured in terms of fairness of treatment, trust, and the amount of which the implicit deal or contract is perceived as being delivered in reflection of a set of obligations or some sort of exchange (Guest 1996). The outcomes as a result of the content of the contract are the employee attitudes and behaviours. The CIPD (2005) found that employees attitudes of trust, fairness and delivery of the deal are major determents to gaining a psychological contract which creates employee commitment and satisfaction. Robinson (1996) (as quoted within Bosch-Sjtsema 2007) claimed that expectations are often shaped by past experience, social norms and observations that are influencing factors to the contract. It was also asserted by Rousseau (2001) that these promise based psychological contracts take the form of a mental model or schema over time. She found that an employees pre-employment experiences, recruiting practices within the company and on the job socialisation as influencing factors to the formation of these schemas which may differ the content or form that an individuals psychological contract takes. 2.1 The Purpose of Psychological Contract According to Bloisi et al., (2003; p.123) the psychological contract is considered as workers implicit expectations about what they are expected to contribute to an organisation and what they will receive in return (Bloisi et al., 2003 p. 123) In a similar way Schein (1965) defined that The notion of a psychological contract implies that there is an unwritten set of expectations operating at all times between every member of an organisation and the various managers and others in that organisation (Schein 1965 as quoted within Armstrong 2003, p 297). According to Hiltrop (1995), it has been noticed there is a significant rate of change of the economic environment in which the organisations work during the last twenty years. Increasing competition, globalisation of markets has demanded greater flexibility and productivity of organisations, as well as new strategies focused on innovation and speed. In the psychological contract the perceived responsibility of an organization influenced by employees expectation ( Cheong Kim 2009). As a result, the terms of old psychological contract has changed radically which earlier gave security, stability and predictability to the relationship between employer and employee (Hiltrop, 1995 p. 286 287). Moreover, the above definition stated by Schein (1965) was amplified by Rousseau and Wade-Benzoni (1994) who stated that Psychological contracts refer to beliefs that individuals hold regarding promises made, accepted and relied upon themselves and another. (In case of organisations, these parties include an employee, client, manager, and/or organisation as a whole.) Because psychological contracts represent how people interpret promises and commitments, both parties in the same employment relationship (employer and employee) can have different views regarding specific terms. (Rousseau and Wade-Benzoni, 1994 p. 463-89) Guest and Conway (1998) summarise stating that since the psychological contract is not written down formally it lacks the characteristics of the formal contract due to which it has no beginning and no end and which is why it cannot be enforced in a court or a tribunal. Guest and Conway (1998) also believe that: The psychological contract is best seen as a metaphor; a word or a phrase borrowed from another context which help us make sense of our experience. The psychological contract is a way of interpreting the state of the employment relationship and helping to plot significant changes (Guest and Conway, 1998 as quoted in Armstrong, 2003 p. 298). 2.1.1 The importance of Psychological Contract The importance of the psychological contract was emphasized by Schein (1965) suggests that the extent to which people work effectively and are committed to the organisation depends on the degree to which their own expectation of what the organisation will provide them and in return what the organisation expects of them; and the nature of what actually is exchanged for example, money in exchange for time at work, security in exchange for hard work and loyalty, and various combinations of other things (Schein, 1965 as quoted within Armstrong, 2003, p 299). The HR profession will have significant role to play in the management and balancing of the general or specific psychological contracts of employees. The HR function can act as a focal point for helping to discover employees expectations through collective channels or individual mechanisms, while seeking to provide for the meeting of employees expectations (e.g. Sims, 1994) (Holden and Breadwell, 2001 p. 546). The HR professionals must make sure that different facets of human resource management and the different managers shape and support the psychological contracts in consistent, integrated and balanced manner, (Rousseau and Greller, 1994 p. 385-401). If employees feel that their psychological contract has been disrupted or breached, and then they may withhold or withdraw from the relationships, consciously or unconsciously, (Spindler, 1994: 326- 327). 2.1.2 The Guest model of Psychological Contract This model was formulated by Guest et al, 1996 suggests that the contract should be measured in terms of fairness of treatment, trust, and the extent to which the explicit deal or contract is perceived to be delivered. Figure 2.1: A Model of the psychological contract Causes Organisational culture HRM policy and practice Experience Expectations Alternatives Consequences Fairness Trust The delivery of the deal Content Organisational citizenship Organisational commitment Motivation Satisfaction and well-being Source: Guest et al, 1996 The simplified Guest model of the psychological contract as illustrated above in Figure 2.1 (as quoted in CIPD 2006) defines it in terms of linkage between the inputs, being the HR practices; the employee features and the companys characteristics together with the content, being the fairness and trust and finally the outputs being the employees behaviour; work performance and delivery. ODonnell and Shields (2002) believes that Guests extended model of the psychological contract (from employee perspective) represents a particularly useful way of understanding the attitudinal and behavioural impact of employment practices at the level of the individual employee (Guest 1998: 659-60) Hiltrop (1995) states that this psychological contract has two important aims, the first for providing a gauge for employers of the type of outputs they are going to obtain from employees and secondly by employees contributing their time and effort for the level of rewards they will receive. 2.1.3 The changing nature of the Psychological Contract According to Hiltrop (1995), there is considerable evidence that shows the changing of the psychological contract in the past decades. Now the employers want to know in advance the outcome of the employees efforts and employees want to know what reward he will get in exchange of the hard work and time spend in the organisation. De Meuse and Tornow (1990) stated that since the 1970s, however, the force that connect employers and employees has become severely stressed organisations deal with the need to cut costs and enhance efficiency, have ever more compacted their workforce and eradicated some of the elements (job security, regular promotions up the corporate ladder, annual wage increases, cheap mortgages, etc.) offered as a rule to employees in the earlier decades (De Meuse and Tornow 1990 p. 203-13). Moreover, people fill in the blanks along the way, and they sometimes do so inconsistently (Rousseau, 1994 as quoted in Hiltrop, 1995 p. 287). In addition to the above context, Kolb et al., (1991) have pointed out that a company staffed by cheated individuals who expect far more than they get is headed for trouble (Kolb et al., 1991 as stated in Hiltrop, 1995 p.287). Conversely, optimistically, some organisations are trying to develop steps that can increase mutuality and to endow with scale for tangential career development and enhance knowledge and skills through opportunities for learning. It has been recognised that the organisations can no longer provide a guaranteed long term job to the employees; they have to take responsibilities to build their skills and give a path for career development. In other words they take steps to improve employability (Armstrong, 2003 p. 302). Two diagrammatic representations are given below which shows the differences between the old and new employment contract by Kissler (1994) and the changing nature of the psychological contract by Hiltrop (1995). Figure 2.2: Difference between the old and new contract. OLD Relationship is predetermined and imposed You are who you work for and what you do Loyalty is defined by performance Employees who do what they are told will work till retirement NEW Relationship is mutual and negotiated You are defined by multiple roles, many external to the organisation Loyalty is defined by output and quality People and skills only needed when required Long-term employment is unlikely; expect and prepare for multiple relationships Source: Kissler, 1994, p. 335-52 Figure 2.3: Changing Psychological Contract . FROM Imposed relationship (compliance, command and control) Permanent employment relationship Focus on promotion Finite job duties Meet job requirements Emphasise on job security and loyalty to the company Training provided by organisation TO Mutual relationship (commitment, participation and involvement) Variable employment relationship people and skills only obtained or retained when required Focus on lateral career development Multiple roles Add value Emphasis on employability and loyalty to own career and skills Opportunities for self-managed learning Source: Hiltrop 1995, p 286-294. Hiltrop (1995) also suggests that a new psychological contract is emerging which is more situational and short term that assumes that each party is less dependent on the other for survival and growth. This new contract was described by Hiltrop (1995) as a worker being employed as long as they provide added value to the company and in return they expect the right to demand interesting and important work with the freedom and resources to perform it well along with performance related pay and training and development. However Armstrong (2006) argued that this could hardly be classified as a balanced contract because employers still dictate their workers employment terms and conditions apart from cases where workers are in demand and there is little supply of skills. Mant (1996) (as quoted within Armstrong 2006) classified workers as resources that are acquired or divested according to shortterm economic circumstances, therefore having little influence over the terms of the contract that their employer offers them. Additionally Taylor (2008) claims that the new relationship is less emotional and is simply an economic exchange, thus moving from relational to transactional. Organisations that are now adopting the rationale behind the use of the flexible firm model (Atkinson 1984) will have developed diverse types of psychological contracts among their workforce. Rousseau and Wade-Benzoni (1995) (as quoted within McDonald and Making 2000) found that temporary staff usually have a transactional contract with significance given to the economic elements of the contract, whilst permanent staff are more likely to have a relational contract involving commitment to the organisation. Additionally Guest (2004) found that the content of temporary workers psychological contract is narrower, transactional and easier to manage on both the employers and employees behalf which temporary workers preferred. An investigation into the company Flexco (Saunders and Thornhill 2005) found that forced change within the company structure through downsizing changed the psychological contract of those on permanent and temporary employment contracts. After the changes it was reported that the temporary workers contained mostly transactional expectations and most permanent employees were found to have relational expectations. However, there were a few exceptions regarding permanent employees, who felt that the changes had violated their contract in terms of interpersonal treatment. These employees felt insecure, and worried that they may face a temporary contract in the future, which emphasises that they no longer felt as though their job was secure. 2.2 The purpose of the performance appraisal. Performance assessment is one of the many people management techniques that classify and order individual hierarchically (Townley, 1994, p.33). A performance appraisal is the process by which a manager evaluates an employees work performance by measurement and comparison with previously established standards (Palmer, 1991 p. 1). According to Palmer (1991), there are two major purpose of conducting performance appraisals. One purpose is to provide the information for the administrative decision making such as the increment of salary, bonuses, promotion and the administrative actions that can be brought by the work performance of the employee. This also helps the organisation to decide whether to introduce for instance, a new incentive system or to improve the present pay and promotion methods. In other words, it is a vehicle to validate and refine organisational actions. For example, it has been noticed in the appraisal data that one of the employee has constant conflicts with the fellow colleague or with the supervisor or manager. Some options can be concluded from the above case, which is, showing more importance to the interpersonal skill while recruiting the new staff or encouraging the present employee to attend the sessions on the conflict management offered by various colleges or providing the employee with one-to-one counselling (Billikopf, 2003 p. 60). The other major purpose is to provide feedback to the employees on their work performance based on the standards established on the job description and analysis. Feedback provided by the supervisor or the manager give the employees an opportunity to develop their career path within the organisation. Feedback can be positive or constructive. Positive appraisal has many benefits and beneficiar

Additive Manufacturing of Medical Implants: A Review

Additive Manufacturing of Medical Implants: A Review E. Gordon Wayne State University College of Engineering Abstract Additive manufacturing has numerous applications and is gaining interest in the biomedical field. The quality of additively manufactured parts is constantly improving, which contributes to their increased use for medical implants in patients. This paper reviews the literature on surgical additive manufacturing applications used on patients, with a focus on the customization of 3D printed implants and the ability to incorporate scaffolds on the implant surface. Scholarly literature databases were used to find general information on the focus topics, as well as case studies of surgical applications of additive manufacturing implants in rodents and humans. The advantages of additive manufacturing medical implants include improved medical outcome, cost effectiveness, and reduced surgery time, as well as customization and incorporated scaffold. Overall, the most effective type of additive manufacturing for the medical implant application is electron beam melting using Ti-6Al-4V because it can produce a high quality, high purity biocompatible implant that has the required mechanical properties. Keywords: Additive Manufacturing, Customized implants, Scaffold, 3D Printing, Ti-6Al-4V Introduction In recent years, additive manufacturing technologies have improved significantly, thus expanding the fields and applications for which they can be used. These 3D printing technologies create physical models from digital models without the need for tool and die and process planning. Additive manufacturing can fabricate prototypes of complex shapes in a variety of materials such as metals, polymers, and nylon. Metal components, in particular, can be used for practical applications such as medical implants: devices manufactured to replace or support a biological structure. The biocompatibility of these metallic devices must be considered, creating rigorous requirements for the material selection and final material properties of the structure. Studies have shown that additive manufacturing successfully produces implants with biocompatible materials that meet the structural requirements [1-6]. 3D printing medical implants can provide many benefits such as the customization and personalization of the implants, cost-effectiveness, increased productivity, and the ability to incorporate scaffold. Using custom made implants, fixtures and surgical tools can help decrease surgery time and patient recovery time, while increasing the likelihood of a successful surgery [7]. Another benefit is the cost efficiency of 3D printing medial implants. Traditional manufacturing methods are cheaper for large quantities, but are more expensive for personalized designs and small production runs [8, 9]. 3D printing is especially cost effective for small-sized implants like spinal or dental implants. 3D printing is also faster than traditional manufacturing if a custom implant needs to be made; traditional methods require milling, forging, and a long delivery time while 3D printing may only take about a day [1]. Another notable benefit of additive manufacturing is the ability to share data files of designs. Files saved as an .STL can be downloaded and printed anywhere in the world. The National Institutes of Health established a 3D Print Exchange to promote open-source sharing of 3D print files for medical models [7]. The most significant benefits for the biomedical industry, however, are the ability to manufacture biocompatible materials, customize implants, and incorporate a porous scaffold surface. Types of Additive Manufacturing The additive manufacturing approach uses computer software to slice a complex 3D model into layers of 2D cross-sections with a minute thickness. The layers are then printed layer by layer depending on the particular method chosen for the application. There are dozens of types of additive manufacturing systems on the market, some of the most common being stereolithography (SLA), direct metal laser sintering (DMLS), selective laser sintering (SLS), selective laser melting (SLM), 3D printing (3DP), and electron beam melting (EBM). These systems are classified according to the form of the raw material, which can be powder, liquid, or solid form [8]. The two types of additive manufacturing that are most commonly used for medical implants are SLS and EBM. Figure 1: Process chain for SLM and EBM. The pre-processing before manufacturing includes 3D modeling, file preparation, and slicing of the 3D model into layers. Post-processing may include heat treatment and polishing of fabricated parts [10]. Selective Laser Sintering An SLS printer uses a powder form of material for printing objects. A laser fuses a single layer of powder by drawing the shape of the object according to the first 2D cross-section of the 3D model. Immediately, the build platform is lowered by the defined layer thickness and another layer of powder is rolled across [10]. The process repeats, fusing each layer one at a time to form the object. SLS can be used with metal, ceramic, and plastic powders. The precision of the laser and the diameter of the powder determines the degree of detail of the final object, so it is possible to create detailed structures with an SLS printer [11]. Figure 2: Schematic of SLS system. The key components of SLM include the laser system (a fiber laser, F-theta and galvanometer used to control the laser beam movement) and the mechanical system (movable build platform and powder roller) [10]. Electron Beam Melting An EBM printer uses a powder form of material for printing objects, similar to SLS. However, while SLS uses a laser to fuse each layer of the powder, EBM uses an electron beam. This energy is delivered through an electric circuit between a tungsten filament inside of the electron gun and the build platform [10]. An electric current heats the filament to emit a beam of electrons [1]. Electric energy is transformed to heat energy which melts the powder on the build platform. The process continues similarly to SLS, where powder is spread across the platform in a thin layer, the cross-section of the object is melted, and then the build platform lowers by the layer thickness. A key element of EBM is that the build chamber is kept under vacuum, which allows the object to be maintain great detail (70-100ÃŽÂ ¼m) [1]. Figure 3: Schematic of EBM system. The key components of EBM include an electron beam system (electron gun assembly, electron beam focusing lens and deflection coils used to control the electron beam) and the mechanical system (movable powder rake and fixed powder cassettes) [10]. Materials of Medical Implants The most common metals used for surgical implants are stainless steel 316L (ASTM F138), Cobalt based alloys (ASTM F75 and ASTM F799) and titanium alloy Ti-6Al-4V (ASTM F67 and F136) [12, 13]. However, these metals have disadvantages such as the potential release of toxic ions and particles due to corrosion that cause inflammation and allergic reactions, affecting biocompatibility [14]. Also, the materials that have an elastic modulus that is not similar to natural bone stimulate new bone growth poorly [12]. Despite this, the low Youngs modulus, high strength, and nonlinear elasticity of titanium-based alloys make it the least harmful choice [3]. The most commonly used titanium alloy is Ti-6Al-4V (Ti64) because it also has a better resistance to corrosion compared to stainless steels and cobalt-based alloys [15]. Additive manufacturing has also been done using Tantalum. Tantalum is biocompatible, hard, ductile, and chemically resistant, but it is expensive and difficult to machine [6] . Titanium based alloys are superior, thus Ti-6Al-V4 is the best material for additive manufacturing medical implants. Material Youngs modulus (GPa) Ultimate tensile strength (MPa) Yield strength (MPa) Elongation (%) TiTa 75.77  ± 4.04 924.64  ± 9.06 882.77  ± 19.60 11.72  ± 1.13 Ti6Al4V 131.51  ± 16.40 1165.69  ± 107.25 1055.59  ± 63.63 6.10  ± 2.57 cpTi 111.59  ± 2.65 703.05  ± 16.22 619.57  ± 20.25 5.19  ± 0.32 Table 1: Tensile properties of SLS produced TiTa, Ti6Al4V and commercially pure titanium samples (n = 5) [16]. Customized Implants Additive manufacturing allows for the design and fabrication of customized prosthetic implants that are created to meet the specific needs of a patient, such as the size, shape, and mechanical properties of the implant. Additive Manufacturing reduces design time as well as manufacturing time because the implant pattern is computer generated with CT and MRI scans, thus removing the need for a physical model [8]. The ability to produce custom implants quickly solves a common problem with orthopedics where standard implants do not always fit the needs of certain patients. Previously, surgeons had to manually modify implants to make them fit the patient [7]. These techniques can be used by professionals in a variety of specialties such as neurosurgery, orthopedics, craniofacial and plastic surgery, oncology, and implant dentistry [8]. One example of an application in which a customized implant is required is craniofacial reconstruction. Craniofacial abnormalities are a diverse group of congenital defects that affect a large number of people and can be acquired at birth or due to injuries or tumors [8]. Standard cranial implants rarely fit a patient precisely because skulls have irregular shapes [7]. The custom implant can be created by using a CT scan to create a 3D virtual model of the patients skull. Then the model can be used with CAD software to design an implant that would perfectly fit the patient [8]. Using custom implants has shown to improve the morphology for large and complex-shaped cranial abnormalities, and some researchers have observed a greater improvement in neurological functions than after similar surgeries using traditionally manufactured implants [17, 18]. Figure 4: Skull model and customized implant for craniofacial reconstruction surgery [8]. Scaffold Additive manufacturing medical implants allows the porosity of the surface to be designed, controlled, and interconnected, which provides better bone growth into implants, thus decreasing the chances of the body rejecting the implant. Additionally, the rough surface quality of 3D printed implants enhances bone-implant fixation [1]. Without scaffold, there is a risk of bone weakening and bone loss around the implant, which is a consequence of stress shielding due to high stiffness of materials [19]. The probability of this problem occurring is lessened when bone can grow into a porous surface of the implant [19]. Cellular lattice structures are classified by stochastic and non-stochastic geometries. The pores in stochastic structures have random variations in size and shape, while the pores in non-stochastic structures have repeating patterns of particular shapes and sizes [10]. The main challenge in additively manufacturing scaffolds is the difficulty to remove the loose powder from within the pores, but an advantage is that additive manufacturing technology allows for the manufacturing of different types of scaffolds if a design requires it; different regions of the implant could have different porosities [1, 10]. The procedure used to achieve the porous areas with traditional manufacturing methods includes coating a smooth surface with other materials such as plasma-sprayed titanium or a titanium wire mesh; however, combining different metals increases the risk of the body rejecting the implant. Additive manufacturing allows the smooth and porous surfaces to be fabricated with the same material, thus decreasing that risk. A variety of additive manufacturing techniques can be used to create the lattice structure, but scaffold can be fabricated by SLS or EBM without the need for support structures, thus making it the most effective method [5]. Figure 5: Acetabular cup with designedFigure 6: (a) Porous femoral stem on the building porous surface [10].platform, (b) post-processed femoral stem [5]. Conclusion There are many advantages to using additive manufacturing to fabricate surgical implants. These benefits include improved medical outcome, cost effectiveness, reduced surgery time, as well as customization and scaffold. Overall, the most effective type of additive manufacturing for the medical implant application is Electron Beam Melting because it can produce a high quality, high purity biocompatible implant that has the required mechanical properties. The recommended metal to use for most implants is the titanium-based alloy Ti-6Al-4V because of its low Youngs modulus, high strength, nonlinear elasticity, and corrosion resistance. Overall, additive manufacturing is an excellent production method for medical implants because it allows surgeons to customize implants and scaffold to the specific needs of the patient. References 1.Petrovic, V., et al., Additive manufacturing solutions for improved medical implants. 2012: INTECH Open Access Publisher. 2.Ahn, Y.K., et al., Mechanical and microstructural characteristics of commercial purity titanium implants fabricated by electron-beam additive manufacturing. Materials Letters, 2017. 187: p. 64-67. 3.Yan, L.M., et al., Improved mechanical properties of the new Ti-15Ta-xZr alloys fabricated by selective laser melting for biomedical application. Journal of Alloys and Compounds, 2016. 688: p. 156-162. 4.Caldarise, S., Hip joint prostheses and methods for manufacturing the same. 1996, Google Patents. 5.Simoneau, C., et al., Development of a porous metallic femoral stem: Design, manufacturing, simulation and mechanical testing. Materials Design, 2017. 114: p. 546-556. 6.Wauthle, R., et al., Additively manufactured porous tantalum implants. Acta Biomaterialia, 2015. 14: p. 217-225. 7.Ventola, C.L., Medical Applications for 3D Printing: Current and Projected Uses. Pharmacy and Therapeutics, 2014. 39(10): p. 704-711. 8.Jardini, A.L., et al., Cranial reconstruction: 3D biomodel and custom-built implant created using additive manufacturing. Journal of Cranio-Maxillofacial Surgery, 2014. 42(8): p. 1877-1884. 9.DUrso, P.S., et al., Custom cranioplasty using stereolithography and acrylic. British Journal of Plastic Surgery, 2000. 53(3): p. 200-204. 10.Sing, S.L., et al., Laser and electronà ¢Ã¢â€š ¬Ã‚ beam powderà ¢Ã¢â€š ¬Ã‚ bed additive manufacturing of metallic implants: A review on processes, materials and designs. Journal of Orthopaedic Research, 2016. 34(3): p. 369-385. 11.Hoy, M.B., 3D printing: making things at the library. Med Ref Serv Q, 2013. 32(1): p. 94-9. 12.Kokubo, T., et al., Bioactive metals: preparation and properties. J Mater Sci Mater Med, 2004. 15(2): p. 99-107. 13.Staiger, M.P., et al., Magnesium and its alloys as orthopedic biomaterials: A review. Biomaterials, 2006. 27(9): p. 1728-1734. 14.Polo-Corrales, L., M. Latorre-Esteves, and J.E. Ramirez-Vick, Scaffold Design for Bone Regeneration. Journal of nanoscience and nanotechnology, 2014. 14(1): p. 15-56. 15.Dinda, G.P., L. Song, and J. Mazumder, Fabrication of Ti-6Al-4V Scaffolds by Direct Metal Deposition. Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science, 2008. 39A(12): p. 2914-2922. 16.Sing, S.L., W.Y. Yeong, and F.E. Wiria, Selective laser melting of titanium alloy with 50 wt% tantalum: Microstructure and mechanical properties. Journal of Alloys and Compounds, 2016. 660: p. 461-470. 17.Rotaru, H., et al., Cranioplasty With Custom-Made Implants: Analyzing the Cases of 10 Patients. Journal of Oral and Maxillofacial Surgery, 2012. 70(2): p. e169-e176. 18.Agner, C., M. Dujovny, and M. Gaviria, Neurocognitive Assessment Before and after Cranioplasty. Acta Neurochirurgica, 2002. 144(10): p. 1033-1040. 19.Shah, F.A., et al., Long-term osseointegration of 3D printed CoCr constructs with an interconnected open-pore architecture prepared by electron beam melting. Acta Biomaterialia, 2016. 36: p. 296-309. Bacillus Thuringiensis: Distribution and Habitat Bacillus Thuringiensis: Distribution and Habitat LITERATURE REVIEW For several decades since its discovery, formulations of Bacillus thuringiensis (B. t.) have been seen as the ideal means of controlling Lepidoteran pests in agriculture because of the many attributes that differentiate this microbial insecticide from the synthetic chemical formulations. No toxicity to mammals, environmental friendliness, apparent immunity to the pesticide resistance phenomenon (no longer true), good integration with other pest control methods and the possibility of being mass produced at farm level at low cost, all made B. thuringiensis the much-needed tool for IPM programmes in developing countries. Research of almost 85 years reveals that Bacillus spp., especially B. thuringiensis and Bacillus sphaericus are the most potent biopesticides (Boucias Pendland, 1998). B. thuringiensis is a species of bacteria that has insecticidal properties that affects a specific range of insect orders. There are at least 34 subspecies of  B. thuringiensis (also called serotypes o r varieties) and possibly over 800 strain isolates (Swadener, 1994). B. thuringiensis accounts for about 5-8% of Bacillus spp. population in the environment (Hastowo et al., 1992). Till date more than 130 species of lepidopteran, dipteran and coleopteran insects are found to be controlled by  B. thuringiensis (Dean, 1984). Historical Background of B. thuringiensis B. thuringiensis are interesting and important bacteria used in the biological control of insect pest which form toxic crystal proteins at the time of sporulation. Perhaps the most well known and widely used biopesticide comes from B. thuringiensis, a bacterium that produces insecticidal proteins during its sporulation. This common soil bacterium, most abundantly found in grain dust from soil and other grain storage facilities, was discovered first in Japan in 1901 by Ishawata and then in 1911 in Germany by Berliner (Baum et al., 1999). It was subsequently found that thousands of strains of B. thuringiensis exist (Lereclus, 1993). The bacterium was isolated from diseased larvae of Anagasta kuehniella, and this finding led to the establishment of B. thuringiensis as microbial insecticide. The first record of its application to control insects was in Hungary at the end of 1920, and in Yugoslavia at the beginning of 1930s, it was applied to control the European corn borer (Lords, 2005). Sporine which was the first commercial product of B. thuringiensis was available in 1938 in France (Waiser, 1986) for the control of flour moth (Jacobs, 1951). Unfortunately, the product was used only for a very short time, due to World War II (Nester et al., 2002). Formation of transgenic plant was also observed. The first reports of insertion of genes encoding for B. thuringiensis delta-endotoxins into plants came in 1987 and the first transgenic plants to express B. thuringiensis toxins were tobacco and tomato plants (van Frankenhuyzen, 1993). In 1957 pacific yeast products commercialized the first strain on B. thuringiensis, named as Thuricide due to the increasing concern of biopesticide over the use of chemical insecticides. B. thuringiensis is a gram-positive spore-forming bacterium that produces crystalline proteins called deltaendotoxins during its stationary phase of growth (Schnepf et al., 1998). The crystal is released to the environment after analysis of the cell wall at the end of sporulation, and it can account for 20 to 30% of the dry weight of the sporulated cells (Schnepf et al., 1998) Distribution Habitat of B. thuringiensis This bacterium is distributed worldwide (Martin Travers, 1989). The soil has been described as its main habitat; however it has also been isolated from foliage, water, storage grains, and dead insects, etc (Iriarte Caballero, 2001). Isolation of strains from dead insects has been the main source for commercially used varieties, which include kurstaki, isolated from A. kuehniella; israelensis, isolated from mosquitoes, and tenebrionis, isolated from Tenebrio monitor larvae (Ninfa Rosas, 2009; Iriarte Caballero, 2001).. The spores of B. thuringiensis persist in soil, and vegetative growth occurs when nutrients are available (DeLucca et al., 1981; Akiba, 1986; Ohba Aizawa, 1986; Travers et al., 1987; Martin Travers, 1989). DeLucca et al., (1981) found that B. thuringiensis represented between 0.5% and 0.005% of all Bacillus species isolated from soil samples in the USA. Martin Travers (1989) recovered B. thuringiensis from soils globally. Meadows (1993) isolated B. thuringiensis from 785 of 1115 soil samples, and the percentage of samples that contained  B. thuringiensis ranged from 56% in New Zealand to 94% in samples from Asia and central and southern Africa. Ohba Aizawa (1986) isolated B. thuringiensis from 136 out of 189 soil samples in Japan. There are several theories on the ecological niche filled by B. thuringiensis. Unlike most insect pathogenic microbes, B. thuringiensis generally recycle poorly and rarely cause natural epizootics in insects, leading to speculation that B. thuringiensis is essentially a soil micro-organism that possesses incidental insecticidal activity (Martin Travers 1989). Evidence to support this view is that B. thuringiensis are commonly reported in the environment independent of insects and there is a lack of association between occurrence and insect activity (van Frankenhuyzen 1993). Meadows (1993) suggested four possible explanations for the presence of B. thuringiensis in soil: 1) rarely grows in soil but is deposited there by insects; 2) may be infective to soil-dwelling insects (as yet undiscovered); 3) may grow in soil when nutrients are available; and 4) an affinity with B. cereus. B. thuringiensis has been found extensively in the phylloplane. Numerous  B. thuringiensis subspecies have been recovered from coniferous trees, deciduous trees and vegetables, as well as from other herbs (Smith Couche, 1991; Damgaard et al., 1997). B. thuringiensis deposited on the upper side of leaves (exposed to the sun) may remain effective for only 1-2 days, but B. thuringiensis on the underside of leaves (i.e. protected from the sun) may remain active for 7-10 days (Swadner, 1994). B. thuringiensis kurstaki has been recovered from rivers and public water distribution systems after an aerial application of Thuricide 16B (Ohana, 1987). Crystal Composition and Morphology The existence of parasporal inclusions in B. thuringiensis was first noted in 1915 (Berliner, 1915), but their protein composition was not delineated until the 1950s (Angus, 1954). Hannay (1953) detected the crystalline fine structure that is a property of most of the parasporal inclusions. B. thuringiensis subspecies can synthesize more than one inclusion, which may contain different ICPs (Hannay, 1953). Depending on their ICP composition, the crystals have various forms (bipyramidal, cuboidal, flat rhomboid, or a composite with two or more crystal types) (Bulla et al., 1977; Hà ¶fte Whiteley, 1989). A partial correlation between crystal morphology, ICP composition, and bioactivity against target insects has been established (Bulla et al., 1977; Hà ¶fte Whiteley, 1989; Lynch Baumann, 1985). Classification of B. thuringiensis subspecies The classification of B. thuringiensis subspecies based on the serological analysis of the flagella (H) antigens was introduced in the early 1960s (de Barjac Bonnefoi, 1962). This classification by serotype has been supplemented by morphological and biochemical criteria (de Barjac, 1981). Until 1977, only 13 B. thuringiensis subspecies had been described, and at that time all subspecies were toxic to Lepidopteran larvae only. The discovery of other subspecies toxic to Diptera (Goldberg Margalit, 1977) and Coleoptera (Krieg et al., 1983) enlarged the host range and markedly increased the number of subspecies. Up to the end of 1998, over 67 subspecies based on flagellar H-serovars had been identified. Genetics of ICP In the early 1980s, it was established that most genes coding for the ICPs reside on large transmissible plasmids, of which most are readily exchanged between strains by conjugation (Gonzà ¡lez Carlton, 1980; Gonzà ¡lez et al., 1981). Since these initial studies, numerous ICP genes have been cloned, sequenced and used to construct  B. thuringiensis strains with novel insecticidal spectra (Hà ¶fte Whiteley, 1989). The currently known crystal (cry) gene types encode ICPs that are specific to either Lepidoptera (cryI), Diptera and Lepidoptera (cryII), Coleoptera (cryIII), Diptera (cryIV), or Coleoptera and Lepidoptera (cryV) (Hà ¶fte Whiteley, 1989). All ICPs described to date attack the insect gut upon ingestion. To date, each of the proteolytically activated ICP molecules with insecticidal activity has a variable C-terminal domain, which is responsible for receptrecognition (host susceptibility), and a conserved  N-terminal domain, which induces pore formation (toxicity) (Li et al., 1991). Most naturally occurring B. thuringiensis strains contain ICPs active against a single order of insects. However, conjugative transfer between B. thuringiensis strains or related species can occur, resulting in new strains with various plasmid contents (Gonzà ¡lez Carlton, 1980). Thus the mobility of the cry genes and the exchange of plasmids may explain the diverse and complex activity spectra observed in B. thuringiensis (Gonzà ¡lez Carlton, 1980; Gonzà ¡lez et al., 1981; Gonzà ¡lez et al., 1982; Reddy et al., 1987; Jarrett Stephenson, 1990). New B. thuringiensis strains have been developed by conjugation that is toxic to two insect orders. Nutritional status of B. thuringiensis Since sporulation and germination in bacilli are dependent on the nutritional status of the organism (Hardwick Foster, 1952), a study of the nutritional requirement of  B. thuringiensis var. thuringiensis is important for delineating the control mechanisms which regulate spore and parasporal crystal formation. Certain amino acids support growth, sporulation and crystal formation of B. thuringiensis var. thuringiensis, while others inhibit the growth (Singer et al., 1966; Singer Rogoff, 1968; Bulla et al., 1975; Nickerson Bulla, 1975; Rajalakshmi Shethna, 1977). A lower concentration of cystine (Nickerson Bulla, 1975) or cysteine (Rajalakshmi Shethna, 1977) promotes growth, sporulation and crystal formation in Î’. thuringiensis, while at a higher concentration of cys/cysSH, only the vegetative growth was observed, (Rajalakshmi Shethna, 1977). Classification of B. thuringiensis The classification of B. thuringiensis subspecies based on the serological analysis of the flagella (H) antigens was introduced in the early 1960s (de Barjac Bonnefoi, 1962). This classification by serotype has been supplemented by morphological and biochemical criteria (de Barjac, 1981). Many strains of B. thuringiensis have been isolated and classified within more than 20 different varieties by serological techniques. On the basis of their potency for insect these varieties have been grouped into five pathotypes: Lepidopteran-Specific (e.g. B. thuringiensis .var Kurstaki) Dipteran-Specific (e.g. B. thuringiensis . var israelensis) Coleopteran-Specific (e.g. B. thuringiensis .var. tenebrionis) Those active against Lepidoptera and Dipter(e.g. B. thuringiensis . var. aizawai) Those with no toxicity recorded in insects (e.g. B. thuringiensis . var. Dakota) Mode of Action The ICP structure and function have been reviewed in detail by Schnepf et al., (1998). Binding of the ICP to putative receptors is a major determinant of ICP specificity and the formation of pores in the midgut epithelial cells is a major mechanism of toxicity (Van Frankenhuyzen, 1993). After ingestion of B. thuringiensis by insect the crystal is dissolved in the insects alkaline gut. Then the digestive enzymes that are present in insects body break down the crystal structure and activate B. thuringiensiss insecticidal component, called the delta-endotoxin (Swadner, 1994). The delta-endotoxin binds to the cells lining the midgut membrane and creates pores in the membrane, upsetting the guts ion balance. The insect soon stops feeding and starves to death (Gill et al., 1992). Target Organisms In the past decades, B. thuringiensis Cry toxins were classified according to the target pest they attacked (Hofte Whiteley, 1998); however, due to the dual toxic activity exhibited by some cry genes and the inconsistencies in the original classification proposed by Hà ¶fte and Whiteley(1998), Crickmore et al., (1998) proposed a revision of the nomenclature for insecticidal crystal proteins, based on the ability of a crystal protein to exhibit some experimentally verifiable toxic effect in a target organism (Crickmore et al., 1998; Hà ¶fte Whiteley, 1998). The diversity of B. thuringiensis is demonstrated in the almost 70 serotypes and the 92 subspecies described to date (Galan-Wong et al., 2006). It is well known that many insects are susceptible to the toxic activity of  B. thuringiensis; among them, lepidopterans have been exceptionally well studied, and many toxins have shown activity against them (Jarret Stephens., 1990; Sefinejad et al., 2008). Order Lepidoptera encompasses the majority of susceptible species belonging to agriculturally important families such as Cossidae, Gelechiidae, Lymantriidae, Noctuidae, Pieridae, Pyralidae, Thaumetopoetidae, Tortricidae, and Yponomeutidae (Iriarte Caballero, 2001). General patterns of use: Commercial applications of B. thuringiensis have been directed mainly against lepidopteran pests of agricultural and forest crops; however, in recent years strains active against coleopteran pests have also been marketed (Tomlin, 1997). Strains of B. thuringiensis kurstaki active against dipteran vectors of parasitic disease organisms have been used in public health programmes (Tomlin, 1997). Applications in agriculture and forestry Commercial use of B. thuringiensis on agricultural and forest crops dates back nearly  30 years, when it became available in France (Van Frankenhuyzen, 1993). Use of  B. thuringiensis has increased greatly in recent years and the number of companies with a commercial interest in B. thuringiensis products has increased from four in 1980 to at least 18 (Van Frankenhuyzen, 1993). Several commercial B. thuringiensis products with B. thuringiensis aizawai, B. thuringiensis kuehniella or B. thuringiensis tenebrionise have been applied to crops using conventional spraying technology. Various formulations have been used on major crops such as cotton, maize, soybeans, potatoes, tomatoes, various crop trees and stored grains. Formulations have ranged from ultralow-volume oil to high-volume, wettable powder and aqueous suspensions (Tomlin, 1997). In the main, naturally occurring B. thuringiensis strains have been used, but transgenic microorganisms expressing B. thuringiensis toxins have been developed by conjugation and by genetic manipulation, and in some cases, these have reached the commercial market (Carlton et al., 1990). These modified organisms have been developed in order to increase host range, prolong field activity or improve delivery of toxins to target organisms. For example, the coleopteran-active cryIIIA gene has been transferred to a lepidopteran-active B. thuringiensis kuehniella (Carlton et al., 1 990). A plasmid bearing an ICP gene has been transferred from B. thuringiensis to a non-pathogenic leaf-colonizing isolate of Pseudomonas fluorescens; fixation of the transgenic cells produces ICP contained within a membrane which prolongs persistence (Gelernter, 1990). Applications in vector control B. thuringiensis Kurstaki has been used to control both mosquitos and blackflies in large-scale programmes (Lacey et al., 1982; Chilcott et al., 1983; Car, 1984; Car de Moor, 1984; Cibulsky Fusco, 1987; Becker Margalit, 1993; Bernhard Utz, 1993). For example, in Germany 23 tonnes of B. thuringiensis Kurstaki wettable powder and 19 000 litres of liquid concentrate were used to control mosquitos (Anopheles and Culex species) between 1981 and 1991 in the Upper Rhine Valley (Becker Margalit, 1993). In China, approximately 10 tonnes of B. thuringiensis Kurstaki have been used in recent years to control the malarial vector, Anopheles sinensis. Resistance of Insect Populations A number of insect populations of several different species with different levels of resistance to B. thuringiensis have been obtained by laboratory selection experiments during the last 15 years (Schnepf et al., 1998). The species include Plodia interpunctella, Cadra cautella, Leptinotarsa decemlineata, Chrysomela scripta, Tricholplusia ni, Spodoptera littoralis, Spodoptera exigua, Heliothis virescens, Ostrinia nubilalis and Culex quinquefasciatus (Schnepf et al., 1998). The Indian meal moth, a pest of grain storage areas, was the first insect to develop resistance to B. thuringiensis. Kurstaki (Swadner, 1994). Resistance progresses more quickly in laboratory experiments than under field conditions due to higher selection pressure in the laboratory (Tabashnik, 1991). No indications of insect resistance to B .thuringiensis were observed in the field, until the development of resistance was ob-served in the diamondback moth in crops where B. thuringiensis had been used repeatedly. Since then, resistance has been observed in the laboratory in the tobacco budworm, the Colorado potato beetle and other insect species (McGaughey, 1992) B. thuringiensiss Ecological Impacts Some of the most serious concerns about widespread use of B. thuringiensis as a pest control technique come from the effects it can have on animals other than the pest targeted for control. All B. thuringiensis products can kill organisms other than their intended targets. In turn, the animals that depend on these organisms for food are also impacted (Swadner, 1994). Effect on Beneficial insects: Many insects are not pests, and any pest management technique needs to be especially concerned about those that are called beneficials, the insects that feed or prey on pest species (Swadner, 1994). B. thuringiensis has impacts on a number of beneficial species. For example, studies of a wasp that is a parasite of the meal moth (Plodia interpunctella) found that treatment with B. thuringiensis reduced the number of eggs produced by the parasitic wasp, and the percentage of those eggs that hatched (Salama, 1993). Production and hatchability of eggs of a predatory bug were also decreased (Salama, 1991). Other insects: Many insects that do not have as directly beneficial importance to agriculture are important in the function and structure of ecosystems. A variety of studies have shown that B. thuringiensis applications can disturb insect communities (Swadner, 1994). Research following large-scale B. thuringiensis applications to kill gypsy moth larvae in Lane County, Oregon, found that the number of oak-feeding caterpillar species was reduced for three years following spraying, and the number of caterpillars was reduced for two years (Miller, 1990). Birds: Because many birds feed on the caterpillars and other insects affected by B. thuringiensis applications, it is not surprising that impacts of B. thuringiensis spraying on birds have been documented (Swadner, 1994). In New Hampshire, when B. thuringiensis-treatment reduced caterpillar abundance, black-throated blue warblers made fewer nesting attempts and also brought fewer caterpillars to their nestlings (Rodenhouse, 1992). Effects on Humans Eight human volunteers ingested 1 gram of a B. thuringiensis kuehniella formulation  (3 ÃÆ'- 109 spores/g of powder) daily for 5 days. Of the eight volunteers, five also inhaled 100 mg of the B. thuringiensis kuehniella powder daily for five days. Comprehensive medical examinations immediately before, after, and 4 to 5 weeks later failed to demonstrate any adverse health effects, and all the blood chemistry and urinalysis tests were negative (Fisher Rosner, 1959). Pivovarov et al., (1977) reported that ingestion of foods contaminated with  B. thuringiensis gastroenteitis at concentrations of 105 to 109 cells/g caused nausea, vomiting, diarrhoea and tenesmus, colic-like pains in the abdomen, and fever in three of the four volunteers studied. The toxicity of the B. thuringiensis gastroenteritis strain may have been due to beta-exotoxin (Ray, 1990). In a purified form, some of the proteins produced by B. thuringiensis are acutely toxic to mammals. However, in their natural form, acute toxicity of commonly-used  B. thuringiensis varieties is limited to caterpillars, mosquito larvae, and beetle larvae (Swadner, 1994). Special Concerns about B. thuringiensis Toxicity The earliest tests done regarding B. thuringiensiss toxicity were conducted using B. thuringiensis var. thuringiensis, a B. thuringiensis strain known to contain a second toxin called beta-exotoxin (Swadner, 1994). The beta-exotoxin is toxic to vertebrates, with an LD 50 (median lethal dose; the dose that kills 50 percent of a population of test animals) of 13-18 milligrams per kilogram of body weight (mg/kg) in mice when injected into the abdomen. An oral dose of 200 mg/kg per day killed mice after eight days (swadner, 1994) Beta-exotoxin also causes genetic damage to human blood cells (Meretoja, 1977).