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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Modelos de seleção de grupo em evolução pré-biótica / Group selection models in pre-biotic evolution

Silva, Ana Tereza Costa 06 September 2000 (has links)
A seleção de grupo foi proposta inicialmente em um contexto ecológico como uma força seletiva agindo sobre o grupo da mesma forma que a seleção individual atua sobre os indivíduos que compõem a população. Apesar da oposição inicial dos biólogos evolucionários tradicionais, nas últimas décadas estes conceitos têm se revelado bastante úteis no estudo de problemas pouco relacionados a sua motivação original. Na primeira parte desta tese, investigamos um modelo de seleção de grupo que usa a extinção diferenciada como força seletiva atuando sobre os grupos. Neste modelo a população é composta de grupos que no jargão de seleção de grupo são denominados demes. As demes por sua vez são habitadas por indivíduos de dois tipos (altruístas não-altruístas) que podem reproduzir-se, sofrer mutação e migrar de uma deme a outra. A dinâmica da população é implementada lançando-se mão de matrizes de transição associadas a cada um destes eventos, levando a um conjunto de equações de recorrência aclopadas cuja iteração dá o estado estacionário da freqüência dos diferentes tipos de demes na população. Examinado inicialmente no regime determinístico, no qual o número de demes é infinito mas o número de indivíduos em cada demes é finito, este modelo revelou o papel desestabilizador das mutações sobre as demes totalmente altruístas. Seguido ao regime determinístico, fizemos um estudo do modelo ainda com extinção diferenciada, considerando o número de demes finito, com vistas a investigar os efeitos provocados pela finitude da população no estado estacionário da freqüência de demes na população. Observamos um aumento ainda maior da instabilidade do estado altruísta provocado pela mutação em face da diminuição da quantidade de demes presentes na população. Finalmente, investigamos um modelo para a evolução da produção de enzimas que usa a seleção de grupo característico em sua concepção. Esta modalidade de seleção de grupo baseia-se no conceito de freqüência média subjetiva, uma freqüência estimada com base na estrutura da população que neste caso também é composta por grupos. Apresentamos uma nova formulação matemática para o mesmo problema com a qual abordamos outro modelo recentemente proposto na literatura que trata da evolução de características altruístas. / Group selection was proposed initially within an ecological context as an evolutionary selective force acting on a group in the same way as the individual selection does on the individuals composing the population. Despite the initial resistance of the conservative evolutionary biologists concerning the ideas of group selection, in the last decades those concepts have been very useful in the investigation of other problems not very correlated to its original motivation. In the first part of this thesis, we investigate a group selection model based on differential extinction as a selective force. In this model, the population is divided into groups, which in the context of group selection are termed demes. The demes are inhabited by two different types of individuals, namely, altruists and non-altruists, which are capable of reproducing themselves, mutating to the other type, or migrating to another deme. The population dynamics is formulated resorting to the transition matrices associated to those events, resulting in a set of coupled recursion equations describing the time evolution of the frequencies of the different types of demes in the population. Considering first the deterministic regime, which corresponds to the limit of infinite demes, each deme containing only a finite number of individuals, this model reveals the destabilizing role of the mutation mechanism on the altruistic demes. Following that analysis, we investigate a stochastic version of the above model, in which the number of demes is finite. The focus was on the effects of the finiteness of the population in the stationary frequencies of the demes. We verified that the instability of the altruistic state due to mutations becomes even more pronounced when the number of demes is reduced. Finally, we investigate a model for the evolution of enzymes production using the concepts of trait-group selection. This kind of group selection is based on the definition of the average subjective frequency, which is estimated by considering the structure of the population. We propose a new mathematical formulation to this problem, which we then use to study a recently proposed model to describe the evolution of altruistic features.
102

Altruism in Action: The Southern Baptist Nurse Missionary in Nigeria, Mid-twentieth Century

Salevan, Alison January 2018 (has links)
Altruism is an imperative for nursing practice and education, but no research has explored its meaning using a historical method. This study aimed to explicate the meaning of altruism through the study of four Southern Baptist nurse missionaries. Ruth Kersey, Amanda Tinkle, Hazel Moon, and Helen Masters served in Nigeria between 1920 and 1981. Their correspondence archives were used as primary sources of data and analyzed for examples of altruism. These women founded orphanages and leprosy treatment programs, and managed clinics and hospitals run by the Southern Baptist Church in Nigeria. Additional interconnected variables of race, gender, and religion were also found to influence their work. The findings of this study supported altruism as a sacrificial behavior motivated by benefiting others. Nursing’s presence in global health, its expansion in leadership, and its future identity are supported by the study of these four nurses. Further research into the work of nurse missionaries in nursing’s past is recommended to increase the understanding of missionary work and altruism.
103

Lethal mind-sets : insights from social and evolutionary psychology into terrorism and radicalisation

Reeve, Zoey January 2015 (has links)
Understanding why people become involved in terrorism is vital to inhibiting recruitment and radicalisation, and therefore preventing terrorist attacks. The question of why people support, engage with, and participate in terrorism is addressed in this thesis. Insights into the causes of terrorism and the process of radicalisation are garnered from social and evolutionary psychology in an effort to add an additional interdisciplinary layer of theoretical understanding to existing political science research. The central argument made in this thesis is that certain psychological processes (social identity), and mechanisms (parochial altruism), influence people to favour ingroups and disfavour outgroups in light of particular intergroup cues. Although social identity theories and the concept of parochial altruism pertain to the same argument for bias towards ingroups, which may also entail bias against outgroups, they arrive at this position in different ways and therefore offer alternative insights into what conditions trigger this bias, and responses to it. A novel experimental paradigm with student participants generated data to investigate the evolved mechanism parochial altruism. Social identity theories were applied to certain features of the radicalisation process to explain how and why identification with the Muslim Umma (worldwide community) occurs, which is a central feature of radicalisation in Al-Qaeda type groups. The insights challenge some of the assumptions made by scholars about the nature of radicalisation and terrorism. This thesis considers the process of radicalisation to be rooted in, and influenced by, normal psychological processes and mechanisms that are present in all humans. Although there are caveats, this thesis provides new avenues of exploration and further research to investigate terrorism, radicalisation, and intergroup conflict more generally.
104

Caridade nos clássicos britânicos / Charity in the British classics

Ribeiro, Gabriel Godinho Ramos 13 September 2017 (has links)
A dissertação aborda o tema da caridade privada e da assistência pública aos pobres em três autores do período clássico da Economia Política britânica: Adam Smith, Thomas Malthus e Jeremy Bentham. Argumenta-se que a questão está intimamente conectada à visão de natureza humana de cada um destes autores, bem como ao contexto histórico marcado pelas legislações conhecidas como \"Leis dos Pobres\" na Inglaterra. Smith aborda o assunto com ênfase em aspectos psicológicos e morais do homem, indicando que existem sérios obstáculos à realização da caridade direcionada aos mais necessitados, principalmente devido a menor propensão humana de simpatizar com o pobre, se comparada à propensão de simpatizar com pessoas mais afortunadas. Entretanto, para Smith, uma sociedade livre seria capaz de reduzir a pobreza extrema através da grande geração de riquezas consequente da divisão do trabalho e acumulação de capital, reduzindo a miséria e a necessidade da caridade. Na obra de Malthus, apresenta-se a visão de natureza humana partindo dos princípios da busca pela sobrevivência e reprodução, que teriam como consequência um aumento populacional sempre que a miséria fosse aliviada. A caridade, neste contexto malthusiano, deveria ser reservada a indivíduos merecedores, com \"freio moral\", e as Leis dos Pobres deveriam ser abolidas. Já a abordagem de Bentham tem base em seu princípio da utilidade, bem como em sua perspectiva de que as motivações humanas são governadas pela busca do prazer e fuga da dor. A partir daí, Bentham evidencia a impossibilidade de que a caridade privada venha a suprir toda a demanda de caridade por indigentes. Para que se resolva o problema, o autor propõe o estabelecimento de uma instituição privada, a National Charity Company, que com subsídio público, se responsabilize pela eliminação da indigência através do encarceramento, auxílio e trabalho compulsório de todos indigentes capazes de realizá-lo. Defende-se que os três autores possuem abordagens diferenciadas, contudo, constata-se que são suas premissas comportamentais - melhor compreendidas como a \"natureza humana\" em suas teorias - que fundamentam muitas de suas conclusões sobre os temas da caridade e Leis dos Pobres. / This dissertation adresses the theme of private charity and public relief to the poor by looking into the work of three authors from the classical period of Political Economy in Britain: Adam Smith, Thomas Malthus and Jeremy Bentham. The argument is that this matter is intimately linked to the conception of human nature of each author, as well as to the historic context related to the legislations known as the \"Poor Laws\" in England. Smith\'s approach is focused on psychological and moral aspects of men, indicating that there are serious obstacles to the offer of charity directed to people in need, mainly due to the lower propensity to sympathize with poor compared to the propensity to sympathize with more with people in better conditions. Nevertheless, to Smtih, a free society would be capable of reducing extreme poverty through the creation of wealth that results from the division of labour and capital accumulation, reducing misery and the need for charity. In Malthus\' work, we find that his view of human nature starts from the principles of survival and reproduction, which have as a consequence a population increase whenever misery is alleviated. Charity, in this malthusian context, should be reserved to individuals that are deserving of receiving it, the ones with \"moral restraint\", and the Poor Laws should be abolished. Bentham\'s approach, on the other hand, starts from both his principle of utility and his perspective that human motivations are governed by the search of pleasure and avoidance of pain. From these ideas, Bentham argues that it is evident the impossibility of private charity being enough to supply for all the demand for charity from indigents. To solve the problem, the author proposes the establishment of a private institution, the National Charity Company, which would, with public subsidies, be responsible for the elimination of indigence through incarceration, relief and compulsory work of all capable indigents in need. It is argued that despite the different approaches from the three authors, in all of them it is possible to see that their behavioral premises (better comprehended as \"human nature\") are the basis of many conclusions on charity and Poor Laws.
105

Essays on the economics of blood donations

Machado, Sara Maria 05 November 2016 (has links)
The first two chapters of this thesis analyze the response of blood donors to several features of the blood market in Portugal. The first provides estimates of the blood supply elasticity using changes in a benefit scheme for regular blood donors. In Portugal, starting from 2003, the government strictly enforced the collection of medical user fees, but with regular donors receiving a waiver. Using within-county variations in the value of the benefit, measured as the user fee for a visit to the Emergency Department, I find that the benefit increases the number of donations, both unconditionally and conditional on the number of blood drives. I estimate a one euro increase in the user fee to increase blood donations by 1.8%, on average. I also estimate a negative elasticity of blood drives with respect to the user fees. This indicates that benefits and blood drives are substitutes in eliciting blood donations. The second chapter analyzes how waiting to donate blood affects donor retention. I use a panel of new blood donors, in Portugal, between 2008 and 2012. I find that higher waiting times make it less likely for first-time donors to donate again, controlling for donor and donation site-specific variables. A 10-minute increase in waiting time until triage results in a 0.6% decrease in donor retention, on average. Donors in the upper tail of the waiting time distribution are driving the effect. New donors at blood drives react more negatively than new donors at blood donor centers. The third chapter (joint with Matteo Galizzi and Raffaele Miniaci) reports experimental evidence on risk preferences measures, from two waves of a representative sample of the UK Household Longitudinal Survey. The subjects responded to three tests: two incentive-compatible lottery tests and a survey test measuring self-reported willingness to take risk. We find significant but low correlations between the responses to the three tests across time. Furthermore, we find that at least two thirds of the subjects made inconsistent choices across lottery tests, when controlling for individual-specific levels of background income. Finally, we find mixed evidence concerning the external validity of these tests.
106

Trois essais sur la taxation des héritages / Three Essays on Inheritance Taxation

Moussault, Erwan 24 September 2018 (has links)
Ce travail de thèse a pour objectif d’étudier l’impact de l’introduction de la taxation des héritages sur la croissance et l’offre de travail, en considérant la diversité des transferts familiaux intergénérationnels. En effet, la transmission familiale peut être éducative, culturelle, patrimoniale, ou encore perçue comme un transfert en temps. Toutes ces formes de solidarités familiales génèrent des externalités, qui impactent différemment la croissance et l’offre de travail, ce qui peut affecter l’efficacité des politiques fiscales. Ainsi, l’impôt successoral réduit l’incitation à épargner mais peut accroître l’investissement éducatif ou les transferts en temps, ce qui peut affecter positivement la productivité des ménages et l’offre de travail. Nous développons ici des modèles théoriques à générations imbriquées avec altruisme envers les descendants. La thèse est composée de trois chapitres. Le premier chapitre permet d'étudier l’impact de la non-disponibilité de la dette publique sur la politique de redistribution intergénérationnelle mise en place par le gouvernement, en utilisant uniquement l'impôt sur les revenus du travail et l'impôt successoral. Il permet aussi d’analyser son effet sur la croissance économique et les transferts familiaux intergénérationnels, consistant en des legs et des dépenses d’éducation, en mettant en évidence le rôle central de la taxation de l’héritage. Le second chapitre propose un modèle avec legs et transferts de temps descendants, dont l’objectif est de montrer les différences entre la taxation de l’héritage et la taxation du capital de cycle de vie, sur le comportement des ménages. Nous montrons que l’utilisation de la taxation de l’héritage à la place de celle du capital peut être une reforme Pareto-améliorante, en fonction de l’effet de la réforme sur l’offre de travail. Enfin, le troisième chapitre s’intéresse aussi à la comparaison entre taxation du capital et taxation de l’héritage, dans un modèle où les dynasties sont différentes en termes de productivité et de niveau d'altruisme. Ce chapitre démontre qu’appliquer l'impôt successoral à la place de celui du capital, peut améliorer à long terme, le bien-être des moins altruistes et, dans certains cas, peut être Pareto-améliorante, si les ressources disponibles pour les plus altruistes augmentent avec la réforme. / This thesis analyzes the impact of inheritance taxation on growth and labor supply, considering the diversity of intergenerational family transfers, such that bequests, parent's education spendings or time transfers. These forms of family solidarity generate externalities, which impact growth and labor supply, and affect the effectiveness of tax policies. Concerning inheritance tax which reduces the incentive to save, it can also increase educational investment or time transfers, which can positively affect household productivity and labor supply. For this purpose, we use overlapping generations models with altruism towards offspring. The thesis is divided into three chapters. The first chapter studies the impact of public debt on intergenerational transfers and on human capital growth, using a simple tax structure with labor and bequest taxes. In this model, parents augment their children's income through education and bequest. When public debt is not available, we show that the long run growth is higher thanks to an increase of the gap between the two taxes, which underlines the role of inheritance taxation. The second chapter proposes a model with rational altruism textit{`a la} Barro, where time transfers and bequests are available to parents. We analyze a shift from capital income tax towards inheritance tax, leaving constant the capital labor ratio. We show that this reform may increase welfare of all generations. Welfare improvement mainly depends on the effect of the reform on the labor supply. This tax reform is also implemented in the third chapter where we consider that dynasties differ in productivity and altruism. We show that the tax reform increases the welfare of less altruistic dynasties but decreases welfare of the most altruistic one. Extending the model with time transfers and elastic labor supply, we identify situations where the tax reform is Pareto improving.
107

Three Essays on Low-skilled Migration, Sustainability and Trade in Services

Milot, Catherine Alexandra 14 May 2012 (has links)
Chapter 1 Low-skilled Migration and Altruism: Population ageing has become a common concern among welfare states, including Canada and most of the OECD countries. Immigration has been identified as a solution to help sustain labour-force growth in industrialized countries, and as the factor most able to mitigate dire predictions of future fiscal imbalances. This chapter examines the impact of low-skilled immigration in a host country where households are altruists with a pay-as-you-go pension system to support the elderly. It demonstrates that low-skilled immigration does not harm the welfare of the domestic population. We use an overlapping-generations model similar to the work of Razin and Sadka (2000) but introduce paternalistic altruism into the life-cycle framework. Within this context of inter-generational altruism and pay-as-you-go pension systems, the initial negative fiscal impact of low-skilled migrants is compensated, thus, all income groups (high and low) and all age groups (young and old) benefit from migration. // Chapter 2 Growth and Sustainability: In light of the major environmental issues experienced by several countries in the last decades, several papers have advocated the rethinking of the role of governments in environmental preservation. This chapter develops an overlapping-generations model of environmental quality and production and investigates the potential role of governmental participation in the preservation of the quality of the environment so as to achieve both economic growth and environmental sustainability. The analysis suggests that long term economic growth and environment sustainability can be maintained with tax-funded environmental programs in a context of a negative production externality on the quality of the environment. // Chapter 3 The Incidence of Geography on Canada’s Services Trade: We estimate geographic barriers to export trade in nine service categories for Canada's provinces from 1997 to 2007 using the structural gravity model. Constructed Home, Domestic and Foreign Bias indexes capture the direct plus indirect effect of services trade costs on intra-provincial, inter-provincial and international trade relative to their frictionless benchmarks. Barriers to services international trade are huge relative to inter-provincial trade and large relative to goods international trade. A novel test confirms the fit of structural gravity with services trade data.
108

Mental health literacy about depression and schizophrenia among Swedish teenagers: a vignette study

Tartani, Evaggelia January 2011 (has links)
Although the prevalence of mental pathology is high, public’s mental health literacy (i.e. knowledge about mental disorders) has not been examined to a great extent. The main purpose of this study was to examine mental health literacy concerning depression and schizophrenia in a setting of adolescents in Sweden. A secondary aim was to explore stigmatizing attitudes towards mentally ill and levels of altruism among adolescents regarding help-seeking behavior. The present study employed qualitative methodology and data were collected through vignettes. A total of 426 high school students living in Stockholm formed the respondents and content analysis showed that among teenagers recognition of both depression and schizophrenia was poor. Moreover, friends and informal sources of help were regarded as best types of help. Furthermore, results indicated stigmatizing beliefs about mental disorders and low levels of altruistic behavior. These results are supported from other similar studies and suggest awareness campaigns to increase mental health literacy among adolescents. Recommendations for future research are also discussed.
109

För andra eller sig själv? : Altruism hos volontärer utomlands och på hemmaplan

Zetterberg, Karin January 2008 (has links)
Forskning har visat att människor hjälper varandra av såväl egoistiska som altruistiska skäl. Hur ter det sig hos volontärer? Ställer volontärer upp för de hjälpbehövandes eller för sin egen skull? Den här uppsatsen syftar till att undersöka volontärers motiv till att hjälpa. Skiljer motiven sig åt beroende på om engagemanget sker i Sverige, inom Europa eller i en annan världsdel? 40 volontärer berättade skriftligt om sina volontärupplevelser. Berättelserna analyserades för att se vilken typ av motiv som angavs mest. Resultatet visade att fler egoistiska än altruistiska motiv angavs totalt sett bland volontärerna, däremot angav Europavolontärer flest altruistiska motiv. Överlag engagerade sig yngre volontärer längre hemifrån. Resultaten kan ge framförallt frivilligorganisationer men också samhället i stort insikt i motiv bakom hjälpinsatser.
110

Gestalning av ett budskap

Carlsson, Olof January 2008 (has links)
Världen blir allt mindre och fler människors levnadsstandard runt om i välden blir allt mer påtaglig. Samtidigt lever vi i västvärlden i ett samhälle som strävar efter att bli individualistiskt. Vi i väst har aldrig tidigare varit så medvetna, kritiska och utbildade som nu, vilket även borde betyda en ökad sympati för våra medmänniskor. Men forskare säger annat. Våra handlingar bygger allt mer på vad som kommer att se bra ut i våra CV. Detta projekt försöker gestalta människans behov av medmänniskor och hennes behov av att känna sig behövd. Projektet producerade en artefakt i form av en golvlampa som ska förmedla projektets budskap. Projektet skiljer sig något från en konventionell designprocess då budskapet och berättelsen är beställaren. Processen bygger på ett förhållningssätt som har kommit att kallas konceptdesign.

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