Christine Langhoff – författare

Essay from the year 2001 in the subject Biology - Human Biology, grade: 70/80, Oxford University (New College), language: English, abstract: Homeostasis is the ability of an organism to maintain a relatively constant internal environment despite changes in and exchanges with the external environment. The importance of a stable internal environment was emphasised by the French physiologist Claude Bernard as early as 1859. By maintaining a relatively stable internal environment, complex multicellular animals are able to live freely in changing external environments. The American physiologist Walter Cannon (1871-1945) called this stable state of the internal environment homeostasis, from the Greek words homeo (same) and stasis (staying). Homeostasis is dynamic and it is the result of compensating regulatory responses performed by homestatic control systems.

Essay from the year 2002 in the subject Geography / Earth Science - Meteorology, Aeronomy, Climatology, grade: 1.1 (A), Oxford University (New College), language: English, abstract: Climates have changed and still are constantly changing at all scales, from local to global, and over varying time-spans. There have been, however, surges of change over time which meteorologists and earth scientists are continually trying to clarify and explain. Global climatic change due to increasing atmospheric concentrations of greenhouse gases has dominated the environmental agenda since the mid 1980s and has engendered considerable international political debate. There is no doubt that over the last 100 years or so, human action has significantly increased the atmospheric concentrations of several gases that are closely related to global temperature. It seems likely that these increased concentrations, which are said to continue to rise in the near future, are already affecting global climate, but our poor knowledge and understanding of the workings of the global heat balance make the current and future situation uncertain. Since the atmosphere is intimately linked to the workings of the biosphere, hydrosphere and lithosphere, the projected changes in climate will have significant effects on all aspects of the natural world in which we live. Many ecological systems will be dramatically changed by global warming and this might lead to changes or even loss of biodiversity.

Essay from the year 2002 in the subject Biology - Ecology, grade: 1.1 (A), Oxford University (New College), language: English, abstract: Biological invasion happens when an organism, any sort of organism, arrives somewhere beyond its previous range. Nowadays, most invasions come from human actions, deliberate or accidental. But natural invasions happen too, from minor changes of range to major invasions across continents. One reason for studying invasions is that many invasive species have become serious pests. The cumulative losses in the USA from some non-indigenous species were estimated at almost $100 billion by 1991. It has to be noted that most invaders fail and have small effects, but that the cumulative effect of those that succeed has been and will continue to be large. Another important fact is that invasions have been an important component of the evolutionary process throughout geological history. Researchers are therefore not only interested in what makes a successful invader, but also in the ecological as well as the genetic impacts of invasions

Essay from the year 2002 in the subject Geography / Earth Science - Demographics, Urban Management, Planning, grade: 1.1, Oxford University (New College), language: English, abstract: Demographic growth has not been uniform over time. Periods of expansion have alternated with others of stagnation and even decline; and the interpretation of these, even for relatively recent historical periods, is not an easy task. The numerical progress of population has been, if not dictated, at least constrained by many forces and obstacles which have determined the general direction of the path of its growth. These can be categorised as biological and environmental. The former are linked to the laws of mortality and reproduction which determine the rate of demographic growth; the latter determine the resistance which these laws encounter and further regulate the rate of growth. Biological and environmental factors affect each other reciprocally and so are not independent of one another. For the most part the mechanisms for re-establishing an equilibrium of population growth are the product of choice (fertility, nuptiality and migration) although some are automatic. The sizes of households and families have varied over time, but they seem to have been similar in different societies despite differences in the types of households. It has to be noted that the European marriage and family formation is neither universal nor is it totally unique.

Essay from the year 2002 in the subject Geography / Earth Science - Physical Geography, Geomorphology, Environmental Studies, grade: 1.1 (A), Oxford University (New College), language: English, abstract: Fertility is directly determined by so-called intermediate fertility variables or proximate determinants which are, in turn, affected by indirect determinants such as socio-economic, cultural and environmental variables. Many different proximate determinants influence fertility and the relationship between them and the level of fertility can be analysed using a comprehensive model. The result of this analysis shows that variations in four factors - marriage, contraception, lactation and induced abortion - are the primary proximate causes of fertility differences among populations. While fertility variations can always be traced to variations in one or more of the intermediate variables, the scope for variation differs among the variables as does their degree of influence in different societies and over time within societies.

Essay from the year 2002 in the subject Geography / Earth Science - Miscellaneous, grade: 1.1 (A), Oxford University (New College), language: English, abstract: Rev. Thomas Robert Malthus published his first Essay on the Principle of Population in 1798 in order to refute the views expressed by utopian writers and philosophers who believed that society could be reshaped in a new form which would lead to a better life for all. Malthus thought that this would never work simply because there would never be enough food to support an idealistic society. In his works Malthus set up laws about society based on past and present evidence and he tried to make future predictions of populations. Although his work has been very influential, it was his fate to frame an analysis of the relationship between population, economy and society during the last generation to which it was applicable. There have been many studies to show whether Malthus was correct for his time and some limitations of his writings have been pointed out. Some of the main limitations of his works are concerned with his views of non-modern Western and non-modern societies.

Essay from the year 2002 in the subject Archaeology, grade: 2i (B), Oxford University (New College), language: English, abstract: Exhange is the chief means by which things move from one person to another and it is an important way in which people create and maintain social hierarchy. It is a richly symbolic activity as all exchanges have got a social meaning which can be analysed and therefore gift exchange can give us insights into the social structures of societies. Exchange is also universal: it is unknown for people to produce and then consume everything directly, without any intervening exchanges at all and this means that gift exchange systems are an important aspect of life which can be studied in every society and different kinds of exchange systems can be compared. An example of a society in which the exchange of gifts can tells something about their social structure are the Trobrianders.

Essay from the year 2002 in the subject Sociology - General and Theoretical Directions, grade: 2ii (B), Oxford University (New College), language: English, abstract: Both functionalism and symbolic interactionism are sociological theories i.e. sets of ideas which provide an explanation for human society. Like all theory, sociological theory is selective because it cannot explain everything or account for the infinite amount of data that exist. Theories are therefore selective in terms of their priorities and perspectives and the data they define as significant. As a result, they provide a particular and partial view of reality. There are a wide variety of sociological theories, and they can be grouped together according to various criteria. One of the most important of these is the distinction between structural or macro perspectives and social action or micro perspectives. These perspectives differ in the way they approach the analysis of society. Functionalism is an example of a macro perspective as it analyses the way society as a whole fits together whereas symbolic interactionism is a micro perspective because it stresses the meaningfulness of human behaviour and denies that it is primarily determined by the structure of society.

Essay from the year 2002 in the subject Biology - Genetics / Gene Technology, grade: 1.1 (A), Oxford University (New College), language: English, abstract: Discuss the distribution of genetic diversity found in human and chimpanzee populationsby Christine Langhoff In the mid-1980s one of the most important studies by Sibley and Ahlquist on our relationship to apes and monkeys found that our closest relatives are the chimpanzees and the bonobos. The study of genetic diversity within both human and chimpanzee populations has been of major interest as researchers have been and are still trying to find out about the differences in genetic diversity between the two otherwise so closely related species. The genetic diversity refers to the amount of genetic variation found in a population. It has been discovered that chimpanzees have a greater total genetic diversity than humans, but that there are exceptions such as in the major histocompatibility complex in which chimpanzees display a low genetic diversity. I am going to explore how the total genetic diversity is surveyed in and distributed among human and chimpanzee populations and I am going to compare their levels of total diversity. I am also going to explore whether different types of polymorphism reveal the same patterns of distribution within and among populations. There are both experimental and statistical methods for studying genetic diversity within and between populations. The experimental methods include electrophoresis and the Polymerase Chain Reaction. Electrophoresis has mainly been used for proteins (primarily for enzymes) as it is easily determined when an enzyme has an amino acid replacement resulting in a difference in its overall mobility (i.e. an allozyme) because it will have an altered electrophoretic mobility. DNA restriction fragments can also be separated by electrophoresis and by using the Southern Blot method these can be made visible in order to be studied. Genetic differences resulting in the presence or absence of restriction sites can be identified because they change the length of characteristic restriction fragments. The polymerase chain reaction (PCR) is another method used in surveying the genetic diversity as it is extremely useful for amplifying specific DNA sequences such as the many DNA polymorphisms that are studied. (Hartl and Clark, 1997)[...]

Seminar paper from the year 2002 in the subject Archaeology, grade: 2.1 (B), Oxford University (New College), language: English, abstract: Compare and contrast social and biological approaches to the study of kinshipby Christine Langhoff Kinship is the study of cultural interpretations of social relationships and social groups that are formed among people who stand in biological or quasi-biological relationships to each other. There are two main approaches to the study of kinship: the biological approach and the social approach. Both approaches can be further divided into different approaches. In the biological approach for example there are socio-ecological, socio-biological and evolutionary theories whereas in the social ones there are theories which try to explain overall patterns of kinship and others which state that one cannot make any generalisations about kinship patterns in different societies. Both approaches try to explain the different types of kinship structures and descent patterns but they do so in different ways. Biological theories often compare nonhuman primate kinship systems with those of humans and they also try to find evidence for the evolution of kinship structures. They tend to emphasise biological features within kinship and usually regard kinship systems as well adapted to environmental conditions. Social approaches on the other hand are more concerned about cultural differences between societies which cause the different kinds of kinship and descent structures and they emphasise non-biological relationships within kinship. The biological approach to the study of kinship can be split into many different approaches such as socio-ecological, socio-biological as well as evolutionary approaches. Socio-ecology and socio-biology try to show that human institutions, like the structures of animal societies, are adaptive, that is to say they result from the actions of individuals attempting to maximise their inclusive fitness. This means that in the biological approaches compare human kinship patterns to those found in other animals, in particular in primates. Although they do stress the importance of biological relationships between kin they also accept that people who are not biologically related can be kin too. [...]

Seminar paper from the year 2001 in the subject Biology - Human Biology, grade: 2.1 (B), Oxford University (New College), language: English, abstract: Discuss the roles that hormones play in humansin both reproductive maturation and reproduction itself. by Christine LanghoffHormones are molecules which are transported in the blood and act as chemical messengers. They are produced by various cells and glands that make up the endocrine system. The blood transports the hormones throughout the body, but they only produce responses in certain target cells or organs. In humans hormones play an important role in both reproductive maturation and reproduction itself. Sex differentiationWhen looking at sex differentiation we first have to look at sex determination. Sex is genetically determined by the Y chromosome. This is because if a Y chromosome is present an individual will develop the male gonads (testes) due to a gene called SRY ('sex-determining region Y gene') which is located on the Y chromosome. SRY is a controller gene which regulates the expression of all the other structural genes that are required to make the testis and which lie on other autosomal chromosomes as well as on the X chromosome. The number of X chromosomes or autosomes present does not affect the primary determination of gonadal sex. In both sexes the gonads are derived embryologically from a common precursor made up of two distinct tissues: somatic mesenchymal tissues, which form the matrix of the gonad, and the primordial germ cells (PGCs), which migrate into and colonise this matrix to form the gametes. Both tissues are located in an area called the urogenital ridge. Until the sixth week of uterine life, there is no differentiation of this site, but the primitive medullary cords and the sex cords are formed. At this time (end of sixth week / beginning of seventh week), and in male embryos only, the definitive testis cords are formed. These cords incorporate most of the PGCs within their columns and secrete an outer basement membrane. They are known as the seminiferous cords, and will give rise to the seminiferous tubules of the adult. Of the two cell populations within the cords, the PGCs, now known as prospermatogonia, will give rise to spermatozoa, and the mesodermal cord cells give rise to Sertoli cells. Between the cords, the loose mesenchyme vascularises and develops as stromal tissue, within which cells condense in clusters to form specific endocrine units, the interstitial glands of Leydig. [...]

Essay from the year 2003 in the subject Sociology - Social System and Social Structure, grade: 2.1 (B), Oxford University (New College), language: English, abstract: Durkheim in his book "e;Suicide: A Study in Sociology"e; (1897) stated that "e;the termsuicide is applied to every case of death which results directly or indirectly from apositive or negative act, carried out by the victim himself, knowing that it will producethis result. An attempt is an act defined in the same way, but falling short of actualdeath. He used the study of suicide in order to illustrate his own methodologicalapproach and many studies that followed have been, at least in part, a reaction to hiswork. Durkheim, although acknowledging that there are individual conditions whichcan cause an individual to kill him/herself, emphasised that every society ispredisposed to produce a certain number of voluntary deaths and that thesociologist studies causes that affect not the individual but the group . He believedthat the suicide rate constitutes an order of facts which is unified and definite andthat it can reveal certain aspects of society especially when looking at the differenttypes of suicide that have been committed. I am going to explore Durkheim s theoryof suicide and what he believed a suicide rate reveals about a society. I am furthergoing to look at some other theories of suicide and how these have supported orchallenged Durkheim s views. [...]

Essay from the year 2003 in the subject Biology - Behaviour, grade: 2.1 (B), Oxford University (New College), language: English, abstract: Conflict is very common in the animal kingdom. In many cases conflict between animals is resolved by displaying and actual fighting is avoided, but there are also many examples of fighting, some of which end up in the death of the opponent. From observations of animal conflict it is clear that some circumstances are more conductive to fighting than others, that animals do not always fight when given the opportunity and that individuals vary in the readiness with which they resort to fighting. Such differences in agonistic behaviour often reflect an animal's chances of winning or getting injured and the importance of the issue concerned. I am going to examine why animals fight and when they avoid it.

Essay from the year 2003 in the subject Sociology - Social System and Social Structure, grade: 2.1 (B), Oxford University (New College), language: English, abstract: Class is a concept much used in both sociology as well as everyday language, but itis surrounded by much confusion about its meaning. There are many differentdefinitions of class and many different views on how people can be grouped intoclasses. In sociology there is an ongoing debate whether or not class is a relevantconcept in contemporary societies and whether it can be used to explain any issues. Iam going to look at the different meanings of class . Further I am going toinvestigate whether grouping people into classes helps to explain anything. The use of class to indicate lifestyle, prestige or rank is probably the most commonlyused sense of the term. Here class is bound up with hierarchy, of being higher thanor lower than some other person or group. Rank is often indicated by lifestyles andparticular patterns of consumption. Marx and Weber have provided two of the mostinfluential explanations about what classes are and how they influence society. Marxbelieved that systems of stratification derive from the relationships of social groups tothe means of production. He used the concept class as referring to the main strata inall stratification systems. A class is a social group whose members share the samerelationship to the means of production with the ruling class oppressing the subjectclass. He argued that on the one hand there exists a class in itself which is just therelationship of the social group to the means of production, but on the other hand asocial group only fully becomes a class when it becomes a class for itself , when itsmembers have class consciousness and class solidarity.

Essay from the year 2003 in the subject Sociology - General and Theoretical Directions, grade: 2.1 (B), Oxford University (New College), language: English, abstract: The study of capitalism is a predominant theme in both Marx's and Weber's writings. In conjunction with Marx s Capital , The Protestant Ethic and the Spirit ofCapitalism by Weber constitutes one of the two great theories of capitalism. However, one has to note that both have written a great deal on the theories ofcapitalism. Both writers focus on the historical and causal forces shaping capitalistsociety, but where Marx believed in economic determinism , Weber also believed inso-called non-economic factors of capitalism. He based his analysis on a number ofinterconnections he saw between capitalist development and the influences ofvarious spheres of society such as religion, law and political institutions. I am going togive an overview of the two different explanations for the origin of capitalism by Marxand Weber. Further I am going to investigate who of the two was right or whether thetwo theories can be synthesised. [...]

Essay from the year 2002 in the subject Biology - Genetics / Gene Technology, grade: 2.1 (B), Oxford University (New College), language: English, abstract: The aim of population genetics is to model the dynamics of evolutionary change within and between populations i.e. a group of individuals who exist together in time and space and are capable of interbreeding. In human DNA approximately 0.08% of the nucleotide base pairs varies among individuals and thus populations genetics has been trying to establish why this is so. Four basic evolutionary forces responsible for genetic diversity in populations have been identified: mutation, natural selection, genetic drift and gene flow. Mutations are copying errors during DNA replication and transcriptions, which introduce new alleles into the population. Natural selection is the differential transmission of alleles into the next generation due to the consequences of functional differences on an individual's survival and reproductive success. Genetic drift is the differential transmission of alleles into the next generation as a result of random sampling and has the greatest potential impact in small populations. Gene flow spreads alleles from one population into another via migration, making them more genetically similar to each other, and countering genetic differentiation by drift. I am going to examine the contribution of genetic drift, gene flow and natural selection to the levels of diversity and composition of genetic polymorphisms in different human populations. Further I am going to examine why some populations have greater diversity than others and compare the patterns of genetic diversity of humans and chimpanzees.

Essay from the year 2002 in the subject Biology - Genetics / Gene Technology, grade: 2.1 (B), Oxford University (New College), language: English, abstract: Ultimately, the goal of genetics is the analysis of the genotype of organisms. But the genotype can be identified - and therefore studied - only through its phenotypic effect. This means that two genotypes are recognised as different from each other because the phenotypes of their carriers are different. A problem can be seen with this approach as the actual variation between organisms is usually quantitative, not qualitative. Many different genotypes may have the same average phenotype. At the same time, because of environmental variation, two individuals of the same genotype may not have the same phenotype. This lack of a one-to-one correspondence between genotype and phenotype obscures underlying Mendelian genetics. I am going to explore the use of various statistical techniques for studying quantitative traits with application to behavioural traits. I am also going to examine whether there are behavioural traits with sufficiently high heritabilities to give hope for gene searches and I am going to discuss the difficulties that confront molecular geneticists regarding psychiatric genetics.

Essay from the year 2002 in the subject Biology - Genetics / Gene Technology, grade: 1.1 (A+), Oxford University (New College), language: English, abstract: In the mid-1980s one of the most important studies by Sibley and Ahlquist on our relationship to apes and monkeys found that our closest relatives are the chimpanzees and the bonobos. The study of genetic diversity within both human and chimpanzee populations has been of major interest as researchers have been and are still trying to find out about the differences in genetic diversity between the two otherwise so closely related species. The genetic diversity refers to the amount of genetic variation found in a population. It has been discovered that chimpanzees have a greater total genetic diversity than humans, but that there are exceptions such as in the major histocompatibility complex in which chimpanzees display a low genetic diversity. I am going to explore how the total genetic diversity is surveyed in and distributed among human and chimpanzee populations and I am going to compare their levels of total diversity. I am also going to explore whether different types of polymorphism reveal the same patterns of distribution within and among populations.

Essay from the year 2003 in the subject Medicine - Internal Medicine, grade: 1.1 (A+), Oxford University (New College), language: English, abstract: Cardiovascular disease is the leading cause of death worldwide and thereforemany scientists are interested in finding both ways to prevent and to treat it. Itis a multifactorial disease and thus is being influenced by a variety ofenvironmental and genetic factors and therefore it is difficult to establish themost important risk factors involved in the development of the disease. Theterm risk factor describes those characteristics found, in healthy individuals, tobe independently related to the subsequent occurrence of cardiovasculardisease and, where modifiable, to be reversible. This term includes modifiablelifestyle and biochemical and physiologic characteristics as well as nonmodifiablepersonal characteristics such as age, sex, genetic makeup, earlylife influences and family history of premature cardiovascular disease. When aperson develops cardiovascular disease, the modifiable risk factors continue tocontribute to the progression of the disease and prognosis. Risk factorsinclude smoking, hypertension, changes to lipid levels (e.g. raised totalcholesterol), raised blood glucose, obesity, family history of prematurecardiovascular disease, female hormonal status, dyslipidemia, diabetes, etc. Except for female hormonal status, no risk factor has been recognised asacting on one gender but not on the other. [...]

Bachelor Thesis from the year 2004 in the subject African Studies - Culture and Applied Geography, grade: 2.1 (68.00), Oxford University, language: English, abstract: In many places throughout the developing world, women have a central role in growing food crops, collecting water and fuel-wood, and using materials from plants, trees, and marine ecosystems to prepare medicines for their families or products for sale in markets (WWF, 2002c). For example, women in sub-Saharan Africa are the backbone of the agricultural sector, accounting for 70% of agricultural labour and being responsible for 60% of agricultural production and 80% of food production (Kabeer, 1994). Yet this critical work is often overlooked and many women have little opportunity to participate in decisions about their community's natural resources or join training and capacity-building initiatives designed to promote sustainable resource management (WWF, 2002c). This dissertation seeks to argue that rural women in Madagascar are very important in the management of natural resources; indeed this is one of the main aspects conservationists have to deal with when considering the sustainable use of natural resources (WWF, 2002c; UN, 2000; Ngong and Arrey, 2003). Having discussed the major areas of rural women s work in Africa and their implications for the environment, this dissertation will explore the role of rural women in Madagascar to exemplify the issues associated with resource use in a biodiversity hotspot. First, general research on the topic will be introduced followed by a specific case study of Antandroy women in Analoalo, a village in the Spiny Forest of South-Eastern Madagascar. The dissertation will conclude by examining the importance of women in the use of natural resources and ways in which they could be integrated into sustainable rural development. The question of how rural women can be involved in the conservation of their local environment has become a contentious issue (Rodda, 1991; UN, 2000) and one which needs to be explored. It should be noted that any efforts to involve rural women in conservation projects also need to concentrate on improving the quality of life in rural areas in general, including a sustainable rural economy. Before exploring the case study, I review the major areas of the work of rural women in sub-Saharan Africa showing how closely linked it is to their use of natural resources. Further, the implications for conservation will be highlighted.

Essay from the year 2004 in the subject Psychology - Developmental Psychology, grade: 2.1, Oxford Brookes University, language: English, abstract: Theory of mind has been defined as the ability to think about other people's mental states and form theories of how they think. It is part of the so-called social cognition which is the term given to knowledge about people and affairs. The notion of theory of mind became important in Psychology following an experiment by Premack and Woodruff (1978) in which they attempted to test whether chimpanzees have a theory of mind. After the publication of this paper it was suggested that children could be tested to see if they had a theory of mind by giving them a false belief task. This is a test to see whether a child will act on a knowingly incorrect belief, or be aware that a second person who is not in possession of a certain piece of information may act incorrectly. Over the last decades many experiments with false belief tasks were conducted in order to test when children develop theory of mind and the results have shown that after about four years of age children realise that another person can have inaccurate belief about the world. However, it has been argued by some researchers that children develop theory of mind earlier and others have stressed that theory of mind cannot be regarded as fully developed in four-year-old children, but rather as a skill that develops for several years after children are successful on typical false belief tasks. I am going to explore some of the studies and arguments dealing with the question of when children can be said to have a theory of mind.

Essay from the year 2004 in the subject Psychology - Developmental Psychology, grade: 2.1, Oxford Brookes University, language: English, abstract: Many researchers have tried to identify environmental factors that can cause intellectual deficits. These include malnutrition, deprivation of parental care, abuse, prenatal drug exposure or exposure to stress hormones, parental style and so on. It is important to identify such potential factors in order to consider the risk of intellectual deficits. Further one has to investigate how these early developmental influences are connected with the outcome in maturity. It has been suggested by some researchers that certain kinds of early experiences produce irreversible effects. I am going to explore some of the environmental factors that can cause intellectual deficits. Further I am going to investigate whether children can recover from such deficits.

Essay from the year 2003 in the subject Geography / Earth Science - Miscellaneous, grade: 2.1, Oxford Brookes University, language: English, abstract: The decline in European mortality which began in the seventeenth century and accelerated in the eighteenth and nineteenth centuries has two main characteristics: the decline in the crude rate of mortality (the relation between numbers of deaths and the average population in a given year) and a later decline in the rate of infant mortality (the relation between the number of infant deaths under 12 months and the number of registered live births in a given year). Many different explanations for these declines have been given. I am going to consider the McKeown thesis which concluded that improving nutrition is the best explanation for the historical fall in mortality in Britain, as well as the theory that increasing inherited resistance to infectious diseases was the major factor.

Essay from the year 2003 in the subject Biology - Evolution, grade: 1, Oxford Brookes University, language: English, abstract: Prosimians are a suborder of primates and include lemurs, lorises and tarsiers. Although specialised in many respects, living prosimians generally retain more primitive features than do anthropoids (the other suborder of primates); and in many aspects of teeth, skulls and limbs, they reserve a morphology similar to that found in primates of the Eocene epoch, 50 to 40 million years ago. These primitive features have led many scientists to believe that the study of prosimian behaviour might give us some insights into the behaviour of ancestral primates and primate origins. I am going to explore what has been the major 'classic' interpretation of the behaviour of the earliest primates in terms of activity rhythm, locomotion and social behaviour based on the study of modern prosimians and how more recent studies have changed our views on these. Further I am going to explore the major contending views for ecological factors that brought about prosimian origins.