954 resultados para Social structure and change
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Contents: 1. Models of addiction and change 2. The process of human intentional behavior change 3. The well maintained addiction : an ending and a beginning 4. Exploring precontemplation, contemplation, and preparation stages of becoming addicted 5. Repeated and regular use : moving from preparation to action on the road to addiction 6. Precontemplation for recovery : cultivating seeds for change 7. The decision to change : moving from the contemplation to the preparation stage of recovery 8. Preparing for action : creating a plan 9. Taking action to change an addiction 10. The long haul : well-maintained recovery 11. Prevention : interfering with the process of becoming addicted 12. Designing interventions for recovery 13. Research on addiction and change. "The stages-of-change model has become widely known as a framework for conceptualizing recovery. Less well known are the processes that drive movement through the stages or how the stages apply to becoming addicted. From Carlo DiClemente, codeveloper of the Transtheoretical Model, this book offers a panoramic view of the entire continuum of addictive behavior change. Illuminated is the common path that individuals travel as they establish and reinforce new patterns of behavior, whether they are developing an addiction or struggling to free themselves from one, and regardless of the specific addictive behavior. Presenting cutting-edge research with significant clinical implications, the book addresses crucial questions of why, when, and how to intervene to bolster recovery in those already addicted and reach out effectively to people at risk. It is essential reading for clinicians, prevention specialists, and policymakers." [from Book Jacket]This resource was contributed by The National Documentation Centre on Drug Use.
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Plants are sessile organisms, often characterized by limited dispersal. Seeds and pollen are the critical stages for gene flow. Here we investigate spatial genetic structure, gene dispersal and the relative contribution of pollen vs seed in the movement of genes in a stable metapopulation of the white campion Silene latifolia within its native range. This short-lived perennial plant is dioecious, has gravity-dispersed seeds and moth-mediated pollination. Direct measures of pollen dispersal suggested that large populations receive more pollen than small isolated populations and that most gene flow occurs within tens of meters. However, these studies were performed in the newly colonized range (North America) where the specialist pollinator is absent. In the native range (Europe), gene dispersal could fall on a different spatial scale. We genotyped 258 individuals from large and small (15) subpopulations along a 60 km, elongated metapopulation in Europe using six highly variable microsatellite markers, two X-linked and four autosomal. We found substantial genetic differentiation among subpopulations (global F(ST)=0.11) and a general pattern of isolation by distance over the whole sampled area. Spatial autocorrelation revealed high relatedness among neighboring individuals over hundreds of meters. Estimates of gene dispersal revealed gene flow at the scale of tens of meters (5-30 m), similar to the newly colonized range. Contrary to expectations, estimates of dispersal based on X and autosomal markers showed very similar ranges, suggesting similar levels of pollen and seed dispersal. This may be explained by stochastic events of extensive seed dispersal in this area and limited pollen dispersal.
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A hydrophobic cuticle is deposited at the outermost extracellular matrix of the epidermis in primary tissues of terrestrial plants. Besides forming a protective shield against the environment, the cuticle is potentially involved in several developmental processes during plant growth. A high degree of variation in cuticle composition and structure exists between different plant species and tissues. Lots of progress has been made recently in understanding the different steps of biosynthesis, transport, and deposition of cuticular components. However, the molecular mechanisms that underlie cuticular function remain largely elusive.
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BACKGROUND AND AIMS: Data from the literature reveal the contrasting influences of family members and friends on the survival of old adults. On one hand, numerous studies have reported a positive association between social relationships and survival. On the other, ties with children may be associated with an increased risk of disability, whereas ties with friends or other relatives tend to improve survival. A five-year prospective, population-based study of 295 Swiss octogenarians tested the hypothesis that having a spouse, siblings or close friends, and regular contacts with relatives or friends are associated with longer survival, even at a very old age. METHODS: Data were collected through individual interviews, and a Cox regression model was applied to assess the effects of kinship and friendship networks on survival, after adjusting for socio-demographic and health-related variables. RESULTS: Our analyses indicate that the presence of a spouse in the household is not significantly related to survival, whereas the presence of siblings at baseline improves the oldest old's chances of surviving five years later. Moreover, the existence of close friends is a central component in the patterns of social relationships of oldest adults, and one which is significantly associated with survival. Overall, the protective effect of social relationships on survival is more related to the quality of those relationships (close friends) than to the frequency of relationships (regular contacts). CONCLUSIONS: We hypothesize that the existence of siblings or close friends may beneficially affect survival, due to the potential influence on the attitudes of octogenarians regarding health practices and adaptive strategies.
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Fifty-five clinical and environmental Aspergillus fumigatus isolates from Mexico, Argentina, France and Peru were analyzed to determine their genetic variability, reproductive system and level of differentiation using amplified fragment length polymorphism markers. The level of genetic variability was assessed by measuring the percentage of polymorphic loci, number of effective alleles, expected heterozygocity and by performing an association index test (I A). The degree of genetic differentiation and variation was determined using analysis of molecular variance at three levels. Using the paired genetic distances, a dendrogram was built to detect the genetic relationship among alleles. Finally, a network of haplotypes was constructed to determine the geographic relationship among them. The results indicate that the clinical isolates have greater genetic variability than the environmental isolates. The I A of the clinical and environmental isolates suggests a recombining population structure. The genetic differentiation among isolates and the dendrogram suggest that the groups of isolates are different. The network of haplotypes demonstrates that the majority of the isolates are grouped according to geographic origin.
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DNA sequence variation has been associated with quantitative changes in molecular phenotypes such as gene expression, but its impact on chromatin states is poorly characterized. To understand the interplay between chromatin and genetic control of gene regulation, we quantified allelic variability in transcription factor binding, histone modifications, and gene expression within humans. We found abundant allelic specificity in chromatin and extensive local, short-range, and long-range allelic coordination among the studied molecular phenotypes. We observed genetic influence on most of these phenotypes, with histone modifications exhibiting strong context-dependent behavior. Our results implicate transcription factors as primary mediators of sequence-specific regulation of gene expression programs, with histone modifications frequently reflecting the primary regulatory event.
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Pathogens represent a threat to all organisms, which generates a coevolutionary arms race. Social insects provide an interesting system to study host-pathogen interactions, because their defences depend on both the individual and collective responses, and involve genetic, physiological, behavioral and organizational mechanisms. In this thesis, I studied the evolutionary ecology of the resistance of ant queens and workers to natural fungal pathogens. Mechanisms that increase within-colony genetic diversity, like polyandry and polygyny, decrease relatedness among colony mates, which reduces the strength of selection for the evolution and maintenance of altruistic behavior. A leading hypothesis posits that intracolonial genetic diversity is adaptive because it reduces the risk of pathogen transmission. In chapter 1, I examine individual resistance in ant workers of Formica selysi, a species that shows natural variation in colony queen number. I discuss how this variation might be beneficial to resist natural fungal pathogens in groups. Overall my results indicate that there is genetic variation for fungal resistance in workers, a requirement for the 'genetic diversity for pathogen resistance' hypothesis. However I was not able to detect direct evidence that group diversity improves the survival of focal ants or reduces pathogen transmission. Thus, although the coexistence of multiple queens increases the within-colony variance in worker resistance, it remains unclear whether it protects ant colonies from pathogens and whether it is comparable to polyandry in other social insects. Traditionally, it was thought that the immune system of invertebrates lacked memory and specificity. In chapter 2, I investigate individual immunity in ant queens and show that they may be able to adjust their pathogen defences in response to their current environment by means of immune priming, which bears similarities with the adaptive immunity of vertebrates. However, my results indicate that the expression of immune priming in ant queens may be influenced by factors like mating status, mating conditions or host species. In addition, I showed that mating increases pathogen resistance in çhe two ant species that I studied (F. selysi and Lasius niger). This raises the question of how ant queens invest heavily in both maintenance and reproduction, which I discuss in the context of the evolution of social organization. In chapter 3,1 investigate if transgenerational priming against a fungal pathogen protects the queen progeny. I failed to detect this effect, and discuss why the detection of transgenerational immune priming in ants is a difficult task. Overall, this thesis illustrates some of the individual and collective mechanisms that likely played a role in allowing ants to become one of the most diverse and ecologically successful groups of organisms. -- Les pathogènes représentent une menace pour tous les organismes, ce qui a engendré l'évolution d'une course aux armements. Les insectes sociaux sont un système intéressant permettant d'étudier les interactions hôtes-pathogènes, car leurs défenses dépendent de réponses aussi bien individuelles que collectives, et impliquent des mécanismes génétiques, physiologiques, comportementaux et organisationnels. Dans cette thèse, j'ai étudié l'écologie évolutive de la résistance des reines et des ouvrières de fourmis exposées à des champignons pathogènes. Les facteurs augmentant la diversité génétique à l'intérieur de la colonie, comme la polyandrie et la polygynie, diminuent la parenté, ce qui réduit la pression de sélection pour l'évolution et la maintenance des comportements altruistes. Une hypothèse dominante stipule que la diversité génétique à l'intérieur de la colonie est adaptative car elle réduit le risque de transmission des pathogènes. Dans le chapitre 1, nous examinons la résistance individuelle à des pathogènes fongiques chez les ouvrières de Formica selysi, une espèce présentant une variation naturelle dans le nombre de reines par colonie. Nous discutons aussi de la possibilité que ces variations individuelles augmentent la capacité du groupe à résister à des champignons pathogènes. Dans l'ensemble, nos résultats indiquent une variation génétique dans la résistance aux champignons chez les ouvrières, un prérequis à l'hypothèse que la diversité génétique du groupe augmente la résistance aux pathogènes. Cependant, nous n'avons pas pu détecter une preuve directe que la diversité du groupe augmente la survie de fourmis focales ou réduise la transmission des pathogènes. Ainsi, bien que la coexistence de plusieurs reines augmente la variance dans la résistance des ouvrières à l'intérieur de la colonie, la question de savoir si cela protège les colonies de fourmis contre les pathogènes et si cela est comparable à la polyandrie chez d'autres insectes sociaux reste ouverte. Traditionnellement, il était admis que le système immunitaire des invertébrés ne possédait pas de mémoire et était non-spécifique. Dans le chapitre 2, nous avons étudié l'immunité individuelle chez des reines de fourmis. Nous avons montré que les reines pourraient être capables d'ajuster leurs défenses contre les pathogènes en réponse à leur environnement, grâce à une pré-activation du système immunitaire (« immune priming ») ressemblant à l'immunité adaptative des vertébrés. Cependant, nos résultats indiquent que cette pré-activation du système immunitaire chez les reines dépend du fait d'être accouplée ou non, des conditions d'accouplement, ou de l'espèce. De plus, nous avons montré que l'accouplement augmente la résistance aux pathogènes chez les deux espèces que nous avons étudié (F. selysi et Lasius niger). Ceci pose la question de la capacité des reines à investir fortement aussi bien dans la maintenance que dans la reproduction, ce que nous discutons dans le contexte de l'évolution de l'organisation sociale. Dans le chapitre 3, nous étudions si la pré-activation trans-générationelle du système immunitaire [« trans-generational immune priming ») protège la progéniture de la reine contre un champignon pathogène. Nous n'avons par réussi à détecter cet effet, et discutons des raisons pour lesquelles la détection de la pré-activation trans-générationelle du système immunitaire chez les fourmis est une tâche difficile. Dans l'ensemble, cette thèse illustre quelques-uns des mécanismes individuels et collectifs qui ont probablement contribué à la diversité et à l'important succès écologique des fourmis.
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BACKGROUND Socio-economic inequalities in mortality are observed at the country level in both North America and Europe. The purpose of this work is to investigate the contribution of specific risk factors to social inequalities in cause-specific mortality using a large multi-country cohort of Europeans. METHODS A total of 3,456,689 person/years follow-up of the European Prospective Investigation into Cancer and Nutrition (EPIC) was analysed. Educational level of subjects coming from 9 European countries was recorded as proxy for socio-economic status (SES). Cox proportional hazard model's with a step-wise inclusion of explanatory variables were used to explore the association between SES and mortality; a Relative Index of Inequality (RII) was calculated as measure of relative inequality. RESULTS Total mortality among men with the highest education level is reduced by 43% compared to men with the lowest (HR 0.57, 95% C.I. 0.52-0.61); among women by 29% (HR 0.71, 95% C.I. 0.64-0.78). The risk reduction was attenuated by 7% in men and 3% in women by the introduction of smoking and to a lesser extent (2% in men and 3% in women) by introducing body mass index and additional explanatory variables (alcohol consumption, leisure physical activity, fruit and vegetable intake) (3% in men and 5% in women). Social inequalities were highly statistically significant for all causes of death examined in men. In women, social inequalities were less strong, but statistically significant for all causes of death except for cancer-related mortality and injuries. DISCUSSION In this European study, substantial social inequalities in mortality among European men and women which cannot be fully explained away by accounting for known common risk factors for chronic diseases are reported.
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The first decade of the twenty-first century may be remembered for the rebirth of consensus on labour market policy. After three decades of bitter political and ideological controversy between a neo-liberal and a traditional social democratic approach, a new model, often labelled flexicurity, has emerged. This model is promoted by numerous political organisations since it promises to put an end to the old trade-off between equality and efficiency. Several countries are embracing the flexicurity model as a blueprint for labour market reform, but others, mostly belonging to the 'Mediterranean Rim', are clearly lagging behind. Why is it so difficult for these countries to implement the flexicurity model? This paper argues that the application of a flexicurity strategy in these countries is complicated by the lack of social trust between social partners and the state as well as political economy traditions that highlight the role of labour market regulation as a source of social protection.
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Theories on social capital and on social entrepreneurship have mainly highlighted the attitude of social capital to generate enterprises and to foster good relations between third sector organizations and the public sector. This paper considers the social capital in a specific third sector enterprise; here, multi-stakeholder social cooperatives are seen, at the same time, as social capital results, creators and incubators. In the particular enterprises that identify themselves as community social enterprises, social capital, both as organizational and relational capital, is fundamental: SCEs arise from but also produce and disseminate social capital. This paper aims to improve the building of relational social capital and the refining of helpful relations drawn from other arenas, where they were created and from where they are sometimes transferred to other realities, where their role is carried on further (often working in non-profit, horizontally and vertically arranged groups, where they share resources and relations). To represent this perspective, we use a qualitative system dynamic approach in which social capital is measured using proxies. Cooperation of volunteers, customers, community leaders and third sector local organizations is fundamental to establish trust relations between public local authorities and cooperatives. These relations help the latter to maintain long-term contracts with local authorities as providers of social services and enable them to add innovation to their services, by developing experiences and management models and maintaining an interchange with civil servants regarding these matters. The long-term relations and the organizational relations linking SCEs and public organizations help to create and to renovate social capital. Thus, multi-stakeholder cooperatives originated via social capital developed in third sector organizations produce new social capital within the cooperatives themselves and between different cooperatives (entrepreneurial components of the third sector) and the public sector. In their entrepreneurial life, cooperatives have to contrast the "working drift," as a result of which only workers remain as members of the cooperative, while other stakeholders leave the organization. Those who are not workers in the cooperative are (stake)holders with "weak ties," who are nevertheless fundamental in making a worker's cooperative an authentic social multi-stakeholders cooperative. To maintain multi-stakeholder governance and the relations with third sector and civil society, social cooperatives have to reinforce participation and dialogue with civil society through ongoing efforts to include people that provide social proposals. We try to represent these processes in a system dynamic model applied to local cooperatives, measuring the social capital created by the social cooperative through proxies, such as number of volunteers and strong cooperation with public institutions. Using a reverse-engineering approach, we can individuate the determinants of the creation of social capital and thereby give support to governance that creates social capital.