776 resultados para Social and Economic Geography


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Many animals that live in groups maintain competitive relationships, yet avoid continual fighting, by forming dominance hierarchies. We compare predictions of stochastic, individual-based models with empirical experimental evidence using shore crabs to test competing hypotheses regarding hierarchy development. The models test (1) what information individuals use when deciding to fight or retreat, (2) how past experience affects current resource-holding potential, and (3) how individuals deal with changes to the social environment. First, we conclude that crabs assess only their own state and not their opponent's when deciding to fight or retreat. Second, willingness to enter, and performance in, aggressive contests are influenced by previous contest outcomes. Winning increases the likelihood of both fighting and winning future interactions, while losing has the opposite effect. Third, when groups with established dominance hierarchies dissolve and new groups form, individuals reassess their ranks, showing no memory of previous rank or group affiliation. With every change in group composition, individuals fight for their new ranks. This iterative process carries over as groups dissolve and form, which has important implications for the relationship between ability and hierarchy rank. We conclude that dominance hierarchies emerge through an interaction of individual and social factors, and discuss these findings in terms of an underlying mechanism. Overall, our results are consistent with crabs using a cumulative assessment strategy iterated across changes in group composition, in which aggression is constrained by an absolute threshold in energy spent and damage received while fighting.

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This paper analyses the effects that technological changes in agriculture would have on environmental, social and economic indicators. Specifically, our study is focused on two alternative technological improvements: the modernization of water transportation systems versus the increase in the total factor productivity of agriculture. Using a computable general equilibrium model for the Catalan economy, our results suggest that a water policy that leads to greater economic efficiency is not necessarily optimal if we consider social or environmental criteria. Moreover, improving environmental sustainability depends less on the type of technological change than on the institutional framework in which technological change occurs. Keywords: agricultural technological changes, computable general equilibrium model, economic impact, water policy

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Diabetes is a growing epidemic with devastating human, social and economic impact. It is associated with significant changes in plasma concentrations of lipoproteins. We tested the hypothesis that lipoproteins modulate the function and survival of insulin-secreting cells. We first detected the presence of several receptors that participate in the binding and processing of plasma lipoproteins and confirmed the internalization of fluorescent LDL and HDL particles in insulin-secreting β-cells. Purified human VLDL and LDL particles reduced insulin mRNA levels and β-cell proliferation, and induced a dose-dependent increase in the rate of apoptosis. In mice lacking the LDL receptor, islets showed a dramatic decrease in LDL uptake and were partially resistant to apoptosis caused by LDL. VLDL-induced apoptosis of β-cells involved caspase-3 cleavage and reduction in levels of the c-Jun N-terminal (JNK) Interacting Protein-1 (IB1/JIP-1). In contrast, the pro-apoptotic signaling of lipoproteins was antagonized by HDL particles or by a small peptide inhibitor of JNK. The protective effects of HDL were mediated, in part, by inhibition of caspase-3 cleavage and activation of the protein kinase Akt/PKB. Heart disease is a major cause of morbidity and mortality among patients with diabetes. When heart failure is refractory to medical therapy and cannot be improved by electrical resynchronization, percutaneous angioplasty or coronary graft bypass surgery, heart transplantation remains a "last resort" therapy. Nevertheless, it is limited by the side effects of immunosuppressive drugs and chronic rejection. Localized expression of immunomodulatory genes in the donor organ can create a state of immune privilege within the graft, and was performed in rodent hearts by infecting cells with an adenovirus encoding indoleamine 2,3-dioxygenase (IDO), the rate-limiting enzyme in the catabolism of tryptophane. Other strategies are based on genetic manipulation of dendritic cells (DCs) with immunosuppressive genes and in vitro exposure of DCs to agents that prevent their maturation by inflammatory cytokines. Finally, we used 5-bromo-2'-deoxyuridine, which is incorporated into DNA and diluted with cell division, to identify long-term label retaining cells in the adult rodent heart. The majority of these cells were positive for the stem cell antigen-1 (Sca-1) and negative for the endothelial precursor marker CD31. They formed cardiospheres in vitro and showed differentiation potential into mesenchymal cell lineages. When cultured in cardiomyogenic differentiation medium, they expressed cardiac-specific genes. Taken together, these data provide evidence of slow-cycling stem cells in the rodent heart. Chronic shortage of donor organs opens the way to cardiac stem cell therapy in humans, although the long way from animal experimentation to routine therapy in patients may still take several years. - Du diabète de type 2 à la maladie coronarienne : trois études sur les dysfonctions de la cellule sécrétrice d'insuline induites par les dyslipidémies, l'immunomodulation dans la transplantation cardiaque, et la thérapie par des cellules souches myocardiques. Le diabète de type 2 a pris les dimensions d'une épidémie, avec des conséquences sociales et économiques dont nous n'avons pas encore pris toute la mesure. La maladie s'accompagne souvent d'une dyslipidémie caractérisée par une hypertriglycéridémie, des taux abaissés de cholestérol HDL, et des concentrations de cholestérol LDL à la limite supérieure de ce qui est considéré comme acceptable. L'hypothèse à la base de cette étude est qu'une modification des taux plasmatiques de lipoprotéines pourrait avoir une influence directe sur la cellule β sécrétrice d'insuline en modifiant sa fonction, sa durée de vie et son taux de régénération. Dans un premier temps, nous avons mis en évidence, sur la cellule β, la présence de plusieurs récepteurs impliqués dans la captation des lipoprotéines. Nous avons confirmé la fonctionnalité de ces récepteurs en suivant l'internalisation de LDL et de HDL marqués. En présence de VLDL ou de LDL humains, nous avons observé une diminution de la transcription du gène de l'insuline, une prolifération cellulaire réduite, et une augmentation de l'apoptose, toutes fonctions de la dose et du temps d'exposition. L'apoptose induite par les VLDL passe par une activation de la caspase-3 et une réduction du taux de la protéine IB1/JIP-1 (Islet Brain1/JNK Interacting Protein 1), dont une mutation est associée à une forme monogénique de diabète de type 2. Par opposition, les HDL, ainsi que des peptides inhibiteurs de JNK, sont capables de contrer la cascade pro-apoptotique déclenchée, respectivement, par les LDL et les VLDL. Ces effets protecteurs comprennent l'inhibition du clivage de la caspase-3 et l'activation de la protéine kinase Akt/PKB. En conclusion, les lipoprotéines sont des éléments clés de la survie de la cellule β, et pourraient contribuer au dysfonctionnement observé dans le pancréas endocrine au cours du développement du diabète. La maladie cardiaque, et plus particulièrement la maladie coronarienne, est une cause majeure de morbidité et de mortalité chez les patients atteints de diabète. Plusieurs stratégies sont utilisées quotidiennement pour pallier les atteintes cardiaques: traitements médicamenteux, électromécaniques par resynchronisation électrique, ou communément appelés « interventionnels » lorsqu'ils font appel à l'angioplastie percutanée. La revascularisation du myocarde par des pontages coronariens donne également de très bons résultats dans certaines situations. Il existe toutefois des cas où plus aucune de ces approches n'est suffisante. La transplantation cardiaque est alors la thérapie de choix pour un nombre restreint de patients. La thérapie génique, en permettant l'expression locale de gènes immunomodulateurs dans l'organe greffé, permet de diminuer les réactions de rejet inhérentes à toute transplantation (à l'exception de celles réalisées entre deux jumeaux homozygotes). Nous avons appliqué chez des rongeurs cette stratégie en infectant le coeur greffé avec un adénovirus codant pour l'enzyme indoleamine 2,3-dioxygénase (IDO), une enzyme clé dans le catabolisme du tryptophane. Nous avons procédé de manière identique in vitro en surexprimant IDO dans les cellules dendritiques, dont le rôle est de présenter les antigènes aux lymphocytes Τ du receveur. Des expériences similaires ont été réalisées en traitant les cellules dendritiques avec des substances capables de prévenir, en partie du moins, leur maturation par des agents pro-inflammatoires. Finalement, nous avons exploré une stratégie utilisée couramment en hématologie, mais qui n'en est encore qu'à ses débuts au niveau cardiaque : la thérapie par des cellules souches. En traitant des rongeurs avec un marqueur qui s'incorpore dans l'ADN nucléaire, le 5-bromo- 2'-deoxyuridine, nous avons identifié une population cellulaire se divisant rarement, positive en grande partie pour l'antigène embryonnaire Sca-1 et négative pour le marqueur endothélial CD31. En culture, ces cellules forment des cardiosphères et sont capables de se différencier dans les principaux types tissulaires mésenchymateux. Dans un milieu de differentiation adéquat, ces cellules expriment des gènes cardiomyocytaires. En résumé, ces données confirment la présence chez le rongeur d'une population résidente de précurseurs myocardiques. En addenda, on trouvera deux publications relatives à la cellule β productrice d'insuline. Le premier article démontre le rôle essentiel joué par la complexine dans l'insulino-sécrétion, tandis que le second souligne l'importance de la protéine IB1/JIP-1 dans la protection contre l'apoptose de la cellule β induite par certaines cytokines.

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Entrepreneurship has been the engine propelling much of the growth of the business sector as well as a driving force behind the rapid expansion of the social sector. This article offers a comparative analysis of commercial and social entrepreneurship using a prevailing analytical model from commercial entrepreneurship. The analysis highlights key similarities and differences between these two forms of entrepreneurship and presents a framework on how to approach the social entrepreneurial process more systematically and effectively. We explore the implications of this analysis of social entrepreneurship for both practitioners and researchers.

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ABSTRACT: BACKGROUND: The prevalence of obesity has increased in societies of all socio-cultural backgrounds. To date, guidelines set forward to prevent obesity have universally emphasized optimal levels of physical activity. However there are few empirical data to support the assertion that low levels of energy expenditure in activity is a causal factor in the current obesity epidemic are very limited. METHODS: The Modeling the Epidemiologic Transition Study (METS) is a cohort study designed to assess the association between physical activity levels and relative weight, weight gain and diabetes and cardiovascular disease risk in five population-based samples at different stages of economic development. Twenty-five hundred young adults, ages 25-45, were enrolled in the study; 500 from sites in Ghana, South Africa, Seychelles, Jamaica and the United States. At baseline, physical activity levels were assessed using accelerometry and a questionnaire in all participants and by doubly labeled water in a subsample of 75 per site. We assessed dietary intake using two separate 24-h recalls, body composition using bioelectrical impedance analysis, and health history, social and economic indicators by questionnaire. Blood pressure was measured and blood samples collected for measurement of lipids, glucose, insulin and adipokines. Full examination including physical activity using accelerometry, anthropometric data and fasting glucose will take place at 12 and 24 months. The distribution of the main variables and the associations between physical activity, independent of energy intake, glucose metabolism and anthropometric measures will be assessed using cross-section and longitudinal analysis within and between sites. DISCUSSION: METS will provide insight on the relative contribution of physical activity and diet to excess weight, age-related weight gain and incident glucose impairment in five populations' samples of young adults at different stages of economic development. These data should be useful for the development of empirically-based public health policy aimed at the prevention of obesity and associated chronic diseases.

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Division of labour among workers is central to the organisation and ecological success of insect societies. If there is a genetic component to worker size, morphology or task preference, an increase in colony genetic diversity arising from the presence of multiple breeders per colony might improve division of labour. We studied the genetic basis of worker size and task preference in Formica selysi, an ant species that shows natural variation in the number of mates per queen and the number of queens per colony. Worker size had a heritable component in colonies headed by a doubly mated queen (h(2)=0.26) and differed significantly among matrilines in multiple-queen colonies. However, higher levels of genetic diversity did not result in more polymorphic workers across single- or multiple-queen colonies. In addition, workers from multiple-queen colonies were consistently smaller and less polymorphic than workers from single-queen colonies. The relationship between task, body size and genetic lineage appeared to be complex. Foragers were significantly larger than brood-tenders, which may provide energetic or ergonomic advantages to the colony. Task specialisation was also often associated with genetic lineage. However, genetic lineage and body size were often correlated with task independently of each other, suggesting that the allocation of workers to tasks is modulated by multiple factors. Overall, these results indicate that an increase in colony genetic diversity does not increase worker size polymorphism but might improve colony homeostasis.

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Estudi realitzat a partir d’una estada al Laboratoire d’études sur les monothéismes (UMR 8584, Centre national de la recherche scientifique / École pratique des hautes études / Université Paris IV-Sorbonne), França, entre 2010 i 2011. Anàlisi de la crisi estructural que afectà a l’església gal•la entre el darrer quart del segle IV i el primer del segle VI, crisi causada per la cristianització a gran escala de les elits aristocràtiques gal•loromanes i per la reivindicació per part d’aquest estament de la translació a l’esfera de la jerarquia institucional de l’Església de la seva preeminència econòmica i social. Aquest procés implicà l’aparició d’algunes interpretacions del “fet existencial cristià” que tractaven de legitimar en el plànol teòric la presa del control de les comunitats cristianes per part de la noblesa senatorial. En relació a aquest últim punt, s’ha donat particular rellevància a l’anomenada “controvèrsia semipelagiana” a Provença, amb especial èmfasi en dos punts: a) la relació entre l’oposició a la teologia agustiniana de la gràcia en alguns cercles monàstics provençals –Marsella, Lérins– i l’emergència en aquests ambients d’una literatura autobiogràfica en la que la reflexió sobre els conceptes de uocatio divina i conuersio a l’ascetisme cristià està estretament vinculada a un esforç teòric de redefinició i reorientació de l’ethos aristocràtic; i b) la relació entre els punts teològics debatuts en aquesta controvèrsia i les concepcions eclesiològiques dels pensadors que hi prengueren part –entengui’s aquí per eclesiologia la definició teòrica dels límits i dels fonaments de la “comunitat cristiana”, amb especial incidència en aquest cas en els plantejaments sobre el rol que l’aristòcrata havia d’exercir en aquestes noves comunitats “transversals”–. Aquest projecte bianual ha posat de manifest la inexistència d’una “teologia semipelagiana”, ateses les antagòniques concepcions eclesiològiques dels autors tradicionalment associats a aquesta corrent de pensament: Cassià entén la comunitat cristiana com una elit ascètica en la que els criteris “laics” d’estratificació social queden suspesos, i rebutja –en la teoria i en la pràctica– que aquesta elit hagi d’assumir el lideratge de la comunitat de fidels seglars; en els autors del cercle de Lérins, en canvi, l’oposició a la teologia agustiniana de la gràcia és inspirada per l’esforç d’importar a tota la comunitat cristiana els ideals monàstics, quelcom que fou també una via de legitimació de l’autoritat dels monjos-bisbes d’origen aristocràtic sorgits del cenobi de Lérins.

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The importance of entrepreneurship for social and economic growth is generally accepted. In addition, intrapreneurship or corporate entrepreneurship is recognized as one of the key elements for organizational development. In this context, corporate culture and, specifically, entrepreneurial competences are considered to be catalysts for intrapreneurship. The main purpose of this paper is to analyse the influence of resources and capabilities on the probability of becoming an intrapreneur. Using data obtained from the Global Entrepreneurship Monitor (GEM) for 39 countries, and a logistic model, the study shows that entrepreneurial resources and capabilities, such as previous entrepreneurial experience, entrepreneurial competences and the ability to detect business opportunities, influence intrapreneurial behaviour. The contributions of this research are both conceptual (advancing corporate entrepreneurship theory) and practical (relating to the design of policies to foster intrapreneurial activities).

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OBJECTIVE: To identify which physician and patient characteristics are associated with physicians' estimation of their patient social status.DESIGN: Cross-sectional ulticentric survey. SETTING: Fourty-seven primary care private offices in Western Switzerland. PARTICIPANTS: Random sample of 2030 patients ≥ 16, who encountered a general practitioner (GP) between September 2010 and February 2011. MAIN MEASURES: PRIMARY OUTCOME: patient social status perceived by GPs, using the MacArthur Scale of Subjective Social Status, ranging from the bottom (0) to the top (10) of the social scale.Secondary outcome: Difference between GP's evaluation and patient's own evaluation of their social status. Potential patient correlates: material and social deprivation using the DiPCare-Q, health status using the EQ-5D, sources of income, and level of education. GP characteristics: opinion regarding patients' deprivation and its influence on health and care. RESULTS: To evaluate patient social status, GPs considered the material, social, and health aspects of deprivation, along with education level, and amount and type of income. GPs declaring a frequent reflexive consideration of their own prejudice towards deprived patients, gave a higher estimation of patients' social status (+1.0, p = 0.002). Choosing a less costly treatment for deprived patients was associated with a lower estimation (-0.7, p = 0.002). GP's evaluation of patient social status was 0.5 point higher than the patient's own estimate (p<0.0001). CONCLUSIONS: GPs can perceive the various dimensions of patient social status, although heterogeneously, according partly to their own characteristics. Compared to patients' own evaluation, GPs overestimate patient social status.

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The article presents and discusses estimates of social and economic indicators for Italy’s regions in benchmark years roughly from Unification to the present day: life expectancy, education, GDP per capita at purchasing power parity, and the new Human Development Index (HDI). A broad interpretative hypothesis, based on the distinction between passive and active modernization, is proposed to account for the evolution of regional imbalances over the long-run. In the lack of active modernization, Southern Italy converged thanks to passive modernization, i.e., State intervention: however, this was more effective in life expectancy, less successful in education, expensive and as a whole ineffective in GDP. As a consequence, convergence in the HDI occurred from the late XIX century to the 1970s, but came to a sudden halt in the last decades of the XX century.

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OBJECTIVES: The objectives were to identify the social and medical factors associated with emergency department (ED) frequent use and to determine if frequent users were more likely to have a combination of these factors in a universal health insurance system. METHODS: This was a retrospective chart review case-control study comparing randomized samples of frequent users and nonfrequent users at the Lausanne University Hospital, Switzerland. The authors defined frequent users as patients with four or more ED visits within the previous 12 months. Adult patients who visited the ED between April 2008 and March 2009 (study period) were included, and patients leaving the ED without medical discharge were excluded. For each patient, the first ED electronic record within the study period was considered for data extraction. Along with basic demographics, variables of interest included social (employment or housing status) and medical (ED primary diagnosis) characteristics. Significant social and medical factors were used to construct a logistic regression model, to determine factors associated with frequent ED use. In addition, comparison of the combination of social and medical factors was examined. RESULTS: A total of 359 of 1,591 frequent and 360 of 34,263 nonfrequent users were selected. Frequent users accounted for less than a 20th of all ED patients (4.4%), but for 12.1% of all visits (5,813 of 48,117), with a maximum of 73 ED visits. No difference in terms of age or sex occurred, but more frequent users had a nationality other than Swiss or European (n = 117 [32.6%] vs. n = 83 [23.1%], p = 0.003). Adjusted multivariate analysis showed that social and specific medical vulnerability factors most increased the risk of frequent ED use: being under guardianship (adjusted odds ratio [OR] = 15.8; 95% confidence interval [CI] = 1.7 to 147.3), living closer to the ED (adjusted OR = 4.6; 95% CI = 2.8 to 7.6), being uninsured (adjusted OR = 2.5; 95% CI = 1.1 to 5.8), being unemployed or dependent on government welfare (adjusted OR = 2.1; 95% CI = 1.3 to 3.4), the number of psychiatric hospitalizations (adjusted OR = 4.6; 95% CI = 1.5 to 14.1), and the use of five or more clinical departments over 12 months (adjusted OR = 4.5; 95% CI = 2.5 to 8.1). Having two of four social factors increased the odds of frequent ED use (adjusted = OR 5.4; 95% CI = 2.9 to 9.9), and similar results were found for medical factors (adjusted OR = 7.9; 95% CI = 4.6 to 13.4). A combination of social and medical factors was markedly associated with ED frequent use, as frequent users were 10 times more likely to have three of them (on a total of eight factors; 95% CI = 5.1 to 19.6). CONCLUSIONS: Frequent users accounted for a moderate proportion of visits at the Lausanne ED. Social and medical vulnerability factors were associated with frequent ED use. In addition, frequent users were more likely to have both social and medical vulnerabilities than were other patients. Case management strategies might address the vulnerability factors of frequent users to prevent inequities in health care and related costs.

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In this chapter we portray the effects of female education and professional achievement on fertility decline in Spain over the period 1920-1980 (birth cohorts of 1901-1950).A longitudinal econometric approach is used to test the hypothesis that the effects of women’s education in the revaluing of their time had a very significant influence on fertility decline. Although in the historical context presented here improvements in schooling were on a modest scale, they were continuous (with the interruption of the Civil War) and had a significant impact in shaping a model of low fertility in Spain. We also stress the relevance of this result in a context such as the Spanish for which liberal values were absent, fertility control practices were forbidden, and labour force participation of women was politically and socially constrained.

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This paper argues that low-stakes test scores, available in surveys, may be partially determined by test-taking motivation, which is associated with personality traits but not with cognitive ability. Therefore, such test score distributions may not be informative regarding cognitive ability distributions. Moreover, correlations, found in survey data, between high test scores and economic success may be partially caused by favorable personality traits. To demonstrate these points, I use the coding speed test that was administered without incentives to National Longitudinal Survey of Youth 1979 (NLSY) participants. I suggest that due to its simplicity its scores may especially depend on individuals' test-taking motivation. I show that controlling for conventional measures of cognitive skills, the coding speed scores are correlated with future earnings of male NLSY participants. Moreover, the coding speed scores of highly motivated, though less educated, population (potential enlists to the armed forces) are higher than NLSY participants' scores. I then use controlled experiments to show that when no performance-based incentives are provided, participants' characteristics, but not their cognitive skills, affect effort invested in the coding speed test. Thus, participants with the same ability (measured by their scores on an incentivized test) have significantly different scores on tests without performance- based incentives.