906 resultados para social ecological model


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The objective of this paper is to identify the political conditions that are most likely to be conducive to the development of social investment policies. It starts from the view put forward by theorists of welfare retrenchment that in the current context of permanent austerity, policy is likely to be dominated by retrenchment and implemented in a way that allows governments to minimise the risk of electoral punishment (blame avoidance). It is argued that this view is inconsistent with developments observed in several European countries, were some welfare state expansion has taken place mostly in the fields of childcare and active labour market policy. An alternative model is put forward, that emphasises the notion of "affordable credit claiming". It is argued that even under strong budgetary pressures, governments maintain a preference for policies that allow them to claim credit for their actions. Since the traditional redistributive policies tend to be off the menu for cost reasons, governments have tended to favour investments in childcare and active labour market policy as credit claiming tools. Policies developed in this way while they have a social investment flavour, tend to be rather limited in the extent to which they genuinely improve prospects of disadvantaged people by investing in their human capital. A more ambitious strategy of social investment sees unlikely to develop on the basis of affordable credit claiming. The paper starts by presenting the theoretical argument, which is then illustrated with examples taken from European countries both in the pre-crisis and in the post-crisis years.

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[cat] En aquest treball presentem un model per explicar el procés d’especialització vitícola assolit als municipis de la província de Barcelona, a mitjans del s. XIX,que cerca entendre com va sorgir històricament un avantatge comparatiu fruit d’un procés que esdevindria un dels punts de partida del procés d’industrialització a Catalunya. Els resultats confirmen els papers jugats pel impuls “Boserupià” de la població en un context d’intensificació de l’ús de la terra, i d’un impuls del mercat “Smithià” en un context d’expansió de la demanda per part de les economies atlàntiques. També es posa de manifest la importància de les dotacions agro-ecològiques i les condicions socioinstitucionals relacionades amb la desigualtat d’ingrés. La difusió de la vinya donà com a resultat unes comunitats rurals menys desiguals fins al 1820, tot i que aquesta desigualtat augmentà de nou a partir d'aleshores.

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En este artículo, a partir de la inversa de la matriz de varianzas y covarianzas se obtiene el modelo Esperanza-Varianza de Markowitz siguiendo un camino más corto y matemáticamente riguroso. También se obtiene la ecuación de equilibrio del CAPM de Sharpe.

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El presente trabajo analiza desde un punto de vista cuantitativo, mediante un modelo de equilibrio general de generaciones sucesivas, los efectos sobre la economía española de eliminar el actual sistema de Seguridad Social e implantar uno de capitalización. El análisis considera el proceso de transición y mide en términos de bienestar, quiénes son los agentes que se opondrían a este tipo de reforma. La consideración de la interacción entre el sistema de seguridad social y el sistema fiscal implica mayores beneficios asociados a una reforma de la seguridad social. Sin embargo, este tipo de reforma sigue generando pérdidas de bienestar para la mayoría de agentes vivos en el momentodel inicio de la reforma, existiendo un sesgo en favor del status quo.

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This article was delivered as an area-paper to the Critical Political Science Meeting of Bilbao, November the 15th 2008, which was organized by the Political Science Department of the UPV (University of the Basque Country). The paper introduces an updated and synthetic version of the model designed by S.M. Lipset and S. Rokkan in 1967 in order to identify the confrontational divides distinctive of European modernization and, in this way, trace the origins of modern party systems. The expanded model proposed is applied, on the one hand, to a variety of empirical cases, prominently the postransitional Spanish case; and on the other, shows its usefulness in order to better understand the distinctive structure of the social conflict of the globalization era.

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Understanding and anticipating biological invasions can focus either on traits that favour species invasiveness or on features of the receiving communities, habitats or landscapes that promote their invasibility. Here, we address invasibility at the regional scale, testing whether some habitats and landscapes are more invasible than others by fitting models that relate alien plant species richness to various environmental predictors. We use a multi-model information-theoretic approach to assess invasibility by modelling spatial and ecological patterns of alien invasion in landscape mosaics and testing competing hypotheses of environmental factors that may control invasibility. Because invasibility may be mediated by particular characteristics of invasiveness, we classified alien species according to their C-S-R plant strategies. We illustrate this approach with a set of 86 alien species in Northern Portugal. We first focus on predictors influencing species richness and expressing invasibility and then evaluate whether distinct plant strategies respond to the same or different groups of environmental predictors. We confirmed climate as a primary determinant of alien invasions and as a primary environmental gradient determining landscape invasibility. The effects of secondary gradients were detected only when the area was sub-sampled according to predictions based on the primary gradient. Then, multiple predictor types influenced patterns of alien species richness, with some types (landscape composition, topography and fire regime) prevailing over others. Alien species richness responded most strongly to extreme land management regimes, suggesting that intermediate disturbance induces biotic resistance by favouring native species richness. Land-use intensification facilitated alien invasion, whereas conservation areas hosted few invaders, highlighting the importance of ecosystem stability in preventing invasions. Plants with different strategies exhibited different responses to environmental gradients, particularly when the variations of the primary gradient were narrowed by sub-sampling. Such differential responses of plant strategies suggest using distinct control and eradication approaches for different areas and alien plant groups.

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A recent study of a pair of sympatric species of cichlids in Lake Apoyo in Nicaragua is viewed as providing probably one of the most convincing examples of sympatric speciation to date. Here, we describe and study a stochastic, individual-based, explicit genetic model tailored for this cichlid system. Our results show that relatively rapid (<20,000 generations) colonization of a new ecological niche and (sympatric or parapatric) speciation via local adaptation and divergence in habitat and mating preferences are theoretically plausible if: (i) the number of loci underlying the traits controlling local adaptation, and habitat and mating preferences is small; (ii) the strength of selection for local adaptation is intermediate; (iii) the carrying capacity of the population is intermediate; and (iv) the effects of the loci influencing nonrandom mating are strong. We discuss patterns and timescales of ecological speciation identified by our model, and we highlight important parameters and features that need to be studied empirically to provide information that can be used to improve the biological realism and power of mathematical models of ecological speciation.

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One third of all stroke survivors develop post-stroke depression (PSD). Depressive symptoms adversely affect rehabilitation and significantly increase risk of death in the post-stroke period. One of the theoretical views on the determinants of PSD focuses on psychosocial factors like disability and social support. Others emphasize biologic mechanisms such as disruption of biogenic amine neurotransmission and release of proinflammatory cytokines. The "lesion location" perspective attempts to establish a relationship between localization of stroke and occurrence of depression, but empirical results remain contradictory. These divergences are partly related to the fact that neuroimaging methods, unlike neuropathology, are not able to assess precisely the full extent of stroke-affected areas and do not specify the different types of vascular lesions. We provide here an overview of the known phenomenological profile and current pathogenic hypotheses of PSD and present neuropathological data challenging the classic "single-stroke"-based neuroanatomical model of PSD. We suggest that vascular burden due to the chronic accumulation of small macrovascular and microvascular lesions may be a crucial determinant of the development and evolution of PSD.

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Segons els estudis existents, en general, els joves són la franja més capacitada per utilitzar el català en tots els àmbits i contextos, però, en conjunt, són els que menys el fan servir. En l"àmbit metropolità, on resideix la majoria de la població de Catalunya, l"ús del català per part dels joves és encara més baix. Alhora, se sap que l"assoliment de la competència de l"expressió oral en català al final del primer cicle de l"ESo no és pas general, per la qual cosa tot sembla indicar que el model escolar actual no té gaire influència en els usos lingüístics més individualitzats. En el marc d"aquesta situació, el Govern de la Generalitat de Catalunya va encarregar al Consell Social de la Llengua Catalana un informe sobre les possibles mesures a prendre per tal d"intervenir-hi i potenciar més l"ús de la llengua. Les conclusions del Consell assenyalen que caldria actuar preferentment sobre els hàbits d"ús intergrupals i socials a través de la formació sociolingüística dels mestres i professors en general, i tot transformant els centres escolars que ho necessitin per la seva composició demolingüística en institucions molt conscients del seu paper en el desenvolupament eficaç d"una L2 (llengua segona). Igualment, es recomana que les polítiques lingüístiques no ignorin el pla cognitivoemotiu dels individus i que s"acompanyin de discursos legitimadors integradors. Per tal d"augmentar la percepció d"utilitat i funcionalitat del català, és imprescindible aconseguir que es converteixi en la llengua laboral més habitual, fet pel qual la intervenció sobre el món socioeconòmic té la màxima importància. En paral·lel, el Govern ha de procurar incidir en tot l"àmbit ludicomediàtic juvenil, ja que és una generació plenament integrada en aquest univers tecnològic.

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L'estructura jeràrquica és una de les característiques fonamentals de les societats de primats, que condiciona en gran mesura el comportament dels individus que conviuen al grup, però quines lleis regeixen la formació i l'estructura d'aquestes jerarquies?, per què en determinats grups els subjectes més dominants se situen al centre del grup i en altres de la mateixa espècie no? En el camp de la conducta animal s"han proposat múltiples hipòtesis però cap totalment satisfactòria, ja que a causa de les múltiples variables que hi influeixen és difícil desenvolupar una teoria que expliqui tota la complexitat que s"observa empíricament. La nostra proposta d"estudi es basa en l"enfocament de la modelització de la conducta adaptativa, la qual ens permet, mitjançant la simulació informàtica, implementar moltes de les variables que autors com Gust (1995), Koenig (2001) i Barta & Giraldeau (1998) han considerat importants per a l"estructura de formacions jeràrquiques en primats. Seguint el model proposat per Hemelrijk (1998), hem programat un simulador basat en agents, en el qual les regles de conducta implementades fan emergir estructures jeràrquiques complexes. En una primera fase de la investigació, que es desenvolupa en el present article, hem replicat els estudis de Hemelrijk (1996). Com els nostres resultats coincideixen amb els obtinguts per Hemelrijk, en posteriors treballs implementarem noves variables al nostre model.

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Human cooperation is typically coordinated by institutions, which determine the outcome structure of the social interactions individuals engage in. Explaining the Neolithic transition from small- to large-scale societies involves understanding how these institutions co-evolve with demography. We study this using a demographically explicit model of institution formation in a patch-structured population. Each patch supports both social and asocial niches. Social individuals create an institution, at a cost to themselves, by negotiating how much of the costly public good provided by cooperators is invested into sanctioning defectors. The remainder of their public good is invested in technology that increases carrying capacity, such as irrigation systems. We show that social individuals can invade a population of asocials, and form institutions that support high levels of cooperation. We then demonstrate conditions where the co-evolution of cooperation, institutions, and demographic carrying capacity creates a transition from small- to large-scale social groups.

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"Health is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity" states the WHO. However, the current focus in this important area seems to be on reducing diseases, while less attention is paid on aspects how to increase the well-being of populations. This paper reviews three examples where well-being has drawn attention of the public and policy makers, and compares the policies of two wealthy countries. The first example is noise. Noise can reduce sleep quality and cause physiological, mental, and social effects. In Switzerland, noise receives a lot of attention by the public. Swiss laws are extensive, e.g., they prohibit trucks and planes from traveling at night. In the USA, there is little public attention and no national strategy against environmental noise. The second example is aesthetics and recreation. Many humans seek contact with the beauty of nature. The USA and Switzerland have similar strategies for achieving clear waters, while the protection of scenic views is approached very differently. Lifestyle is the last example. In the USA, the desire for individual freedom is a leading cause for suburban sprawl, a car-dependent sedentary lifestyle resulting in obesity, asthma and loss of community spirit. In Switzerland, a strict land use planning seeks to balance individual and public interests and stresses public transportation, which seems to be a more promising approach. Paying attention to aspects of well-being while developing political strategies might be a promising model to tackle environmental problems. Successful strategies employed so far seem to include the public, local authorities, politicians and scientists in this process, which might have been a key for their success. [Authors]

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Identifying the geographic distribution of populations is a basic, yet crucial step in many fundamental and applied ecological projects, as it provides key information on which many subsequent analyses depend. However, this task is often costly and time consuming, especially where rare species are concerned and where most sampling designs generally prove inefficient. At the same time, rare species are those for which distribution data are most needed for their conservation to be effective. To enhance fieldwork sampling, model-based sampling (MBS) uses predictions from species distribution models: when looking for the species in areas of high habitat suitability, chances should be higher to find them. We thoroughly tested the efficiency of MBS by conducting an important survey in the Swiss Alps, assessing the detection rate of three rare and five common plant species. For each species, habitat suitability maps were produced following an ensemble modeling framework combining two spatial resolutions and two modeling techniques. We tested the efficiency of MBS and the accuracy of our models by sampling 240 sites in the field (30 sitesx8 species). Across all species, the MBS approach proved to be effective. In particular, the MBS design strictly led to the discovery of six sites of presence of one rare plant, increasing chances to find this species from 0 to 50%. For common species, MBS doubled the new population discovery rates as compared to random sampling. Habitat suitability maps coming from the combination of four individual modeling methods predicted well the species' distribution and more accurately than the individual models. As a conclusion, using MBS for fieldwork could efficiently help in increasing our knowledge of rare species distribution. More generally, we recommend using habitat suitability models to support conservation plans.

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The adaptive function of melanin-based coloration is a long-standing debate. A recent genetic model suggested that pleiotropy could account for covariations between pigmentation, behaviour, morphology, physiology and life history traits. We explored whether the expression levels of genes belonging to the melanocortin system (MC1R, POMC, PC1/3, PC2 and the antagonist ASIP), which have many pleiotropic effects, are associated with melanogenesis (through variation in the expression of the genes MITF, SLC7A11, TYR, TYRP1) and in turn melanin-based coloration. We considered the tawny owl (Strix aluco) because individuals vary continuously from light to dark reddish, and thus, colour variation is likely to stem from differences in the levels of gene expression. We measured gene expression in feather bases collected in nestlings at the time of melanin production. As expected, the melanocortin system was associated with the expression of melanogenic genes and pigmentation. Offspring of darker reddish fathers expressed PC1/3 to lower levels but tended to express PC2 to higher levels. The convertase enzyme PC1/3 cleaves the POMC prohormone to obtain ACTH, while the convertase enzyme PC2 cleaves ACTH to produce α-melanin-stimulating hormone (α-MSH). ACTH regulates glucocorticoids, hormones that modulate stress responses, while α-MSH induces eumelanogenesis. We therefore conclude that the melanocortin system, through the convertase enzymes PC1/3 and PC2, may account for part of the interindividual variation in melanin-based coloration in nestling tawny owls. Pleiotropy may thus account for the covariation between phenotypic traits involved in social interactions (here pigmentation) and life history, morphology, behaviour and physiology.

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This research was conducted in the context of the project IRIS 8A Health and Society (2002-2008) and financially supported by the University of Lausanne. It was aomed at developping a model based on the elder people's experience and allowed us to develop a "Portrait evaluation" of fear of falling using their examples and words. It is a very simple evaluation, which can be used by professionals, but by the elder people themselves. The "Portrait evaluation" and the user's guide are on free access, but we would very much approciate to know whether other people or scientists have used it and collect their comments. (contact: Chantal.Piot-Ziegler@unil.ch)The purpose of this study is to create a model grounded in the elderly people's experience allowing the development of an original instrument to evaluate FOF.In a previous study, 58 semi-structured interviews were conducted with community-dwelling elderly people. The qualitative thematic analysis showed that fear of falling was defined through the functional, social and psychological long-term consequences of falls (Piot-Ziegler et al., 2007).In order to reveal patterns in the expression of fear of falling, an original qualitative thematic pattern analysis (QUAlitative Pattern Analysis - QUAPA) is developed and applied on these interviews.The results of this analysis show an internal coherence across the three dimensions (functional, social and psychological). Four different patterns are found, corresponding to four degrees of fear of falling. They are formalized in a fear of falling intensity model.This model leads to a portrait-evaluation for fallers and non-fallers. The evaluation must be confronted to large samples of elderly people, living in different environments. It presents an original alternative to the concept of self-efficacy to evaluate fear of falling in older people.The model of FOF presented in this article is grounded on elderly people's experience. It gives an experiential description of the three dimensions constitutive of FOF and of their evolution as fear increases, and defines an evaluation tool using situations and wordings based on the elderly people's discourse.