803 resultados para Ellsberg paradox


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The Sarkozy presidency is shot through with paradox and contrast: between a well-elected president swiftly loathed by most voters; a ‘hyper-president’ who probably weakened the office; a talented party leader who lost effective control of his party; a right-wing president who was readily compared to Tony Blair; and an ambitious reformer who promised a clean break with the indecision of his two predecessors but whose record was more timid than his rhetoric. This article interprets Sarkozy’s record in the context of the presidential office, the specific circumstances of his presidency, and of the president’s own personality, skills and shortcomings.

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Simple predator–prey models with a prey-dependent functional response predict that enrichment (increased carrying capacity) destabilizes community dynamics: this is the ‘paradox of enrichment’. However, the energy value of prey is very important in this context. The intraspecific chemical composition of prey species determines its energy value as a food for the potential predator. Theoretical and experimental studies establish that variable chemical composition of prey affects the predator–prey dynamics. Recently, experimental and theoretical approaches have been made to incorporate explicitly the stoichiometric heterogeneity of simple predator–prey systems. Following the results of the previous experimental and theoretical advances, in this article we propose a simple phenomenological formulation of the variation of energy value at increased level of carrying capacity. Results of our study demonstrate that coupling the parameters representing the phenomenological energy value and carrying capacity in a realistic way, may avoid destabilization of community dynamics following enrichment. Additionally, under such coupling the producer–grazer system persists for only an intermediate zone of production—a result consistent with recent studies. We suggest that, while addressing the issue of enrichment in a general predator–prey model, the phenomenological relationship that we propose here might be applicable to avoid Rosenzweig’s paradox.

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Enrichment in resource availability theoretically destabilizes predator–prey dynamics (the paradox of enrichment). However, a minor change in the resource stoichiometry may make a prey toxic for the predator, and the presence of toxic prey affects the dynamics significantly. Here, theoretically we explore how, at increased carrying capacity, a toxic prey affects the oscillation or destabilization of predator–prey dynamics, and how its presence influences the growth of the predator as well as that of a palatable prey. Mathematical analysis determines the bounds on the food toxicity that allow the coexistence of a predator along with a palatable and a toxic prey. The overall results demonstrate that toxic food counteracts oscillation (destabilization) arising from enrichment of resource availability. Moreover, our results show that, at increased resource availability, toxic food that acts as a source of extra mortality may increase the abundance of the predator as well as that of the palatable prey.

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The coexistence of a large number of phytoplankton species on a seemingly limited variety of resources is a classical problem in ecology, known as ‘the paradox of the plankton’. Strong fluctuations in species abundance due to the external factors or competitive interactions leading to oscillations, chaos and short-term equilibria have been cited so far to explain multi-species coexistence and biodiversity of phytoplankton. However, none of the explanations has been universally accepted. The qualitative view and statistical analysis of our field data establish two distinct roles of toxin-producing phytoplankton (TPP): toxin allelopathy weakens the interspecific competition among phytoplankton groups and the inhibition due to ingestion of toxic substances reduces the abundance of the grazer zooplankton. Structuring the overall plankton population as a combination of nontoxic phytoplankton (NTP), toxic phytoplankton, and zooplankton, here we offer a novel solution to the plankton paradox governed by the activity of TPP. We demonstrate our findings through qualitative analysis of our sample data followed by analysis of a mathematical model.

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Nuclear factor kappa B (NF-kappaB) is an inducible transcription factor present in neurons and glia. Recent genetic models identified a role for NF-kappaB in neuroprotection against various neurotoxins. Furthermore, genetic evidence for a role in learning and memory is now emerging. This review highlights our current understanding of neuronal NF-kappaB in response to synaptic transmission and summarizes potential physiological functions of NF-kappaB in the nervous system. This article contains a listing of NF-kappaB activators and inhibitors in the nervous system, furthermore specific target genes are discussed. Synaptic NF-kappaB activated by glutamate and Ca2+ will be presented in the context of retrograde signaling. A controversial role of NF-kappaB in neurodegenerative diseases will be discussed. A model is proposed explaining this paradox as deregulated physiological NF-kappaB activity, where novel results are integrated, showing that p65 could be turned from an activator to a repressor of anti-apoptotic genes.

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Sergio Tenenbaum and Diana Raffman contend that ‘vague projects’ motivate radical revisions to orthodox, utility-maximising rational choice theory. Their argument cannot succeed if such projects merely ground instances of the paradox of the sorites, or heap. Tenenbaum and Raffman are not blind to this, and argue that Warren Quinn’s Puzzle of the Self-Torturer does not rest on the sorites. I argue that their argument both fails to generalise to most vague projects, and is ineffective in the case of the Self-Torturer itself.

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The vast majority of putative solutions to the liar paradox face the infamous revenge problem. In recent work, however, Kevin Scharp has extensively developed an exciting and highly novel ‘inconsistency approach’ to the paradox that, he claims, does not face revenge. If Scharp is right, then this represents a significant step forward in our attempts to solve the liar paradox. However, in this paper, I raise a revenge problem that faces Scharp’s inconsistency approach.

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Corporate Social Responsibility (CSR) has become a strategic and operational reality of the business and academic world. Not that the principles of CSR are always respected or that its practice is consistently applied. Bearing in mind the multi-faceted nature of both CSR and the corporate environment, as well as the paradox of what is taught in Higher Education and what is practised within its own walls, this paper provides a learning cyclical pathway to sustainable CSR implementation and progress review. As well as highlighting the role that Higher Education has to play, the paper emphasises that in order to embed CSR within the corporate environment, questions need to be raised concerning on-going CSR improvement in order to both protect and engage a wide range of stakeholders towards sustainable corporate advantage.

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While many academics are sceptical about the 'impact agenda', it may offer the potential to re-value feminist and participatory approaches to the co-production of knowledge. Drawing on my experiences of developing a UK Research Excellence Framework (REF) impact case study based on research on young caregiving in the UK, Tanzania and Uganda, I explore the dilemmas and tensions of balancing an ethic of care and participatory praxis with research management demands to evidence 'impact' in the neoliberal academy. The participatory dissemination process enabled young people to identify their support needs, which translated into policy and practice recommendations and in turn, produced 'impact'. It also revealed a paradox of action-oriented research: this approach may bring greater emotional investment of the participants in the project in potentially negative as well as positive ways, resulting in disenchantment that the research did not lead to tangible outcomes at local level. Participatory praxis may also pose ethical dilemmas for researchers who have responsibilities to care for both 'proximate' and 'distant' others. The 'more than research' relationship I developed with practitioners was motivated by my ethic of care rather than by the demands of the audit culture. Furthermore, my research and the impacts cited emerged slowly and incrementally from a series of small grants in an unplanned, serendipitous way at different scales, which may be difficult to fit within institutional audits of 'impact'. Given the growing pressures on academics, it seems ever more important to embody an ethic of care in university settings, as well as in the 'field'. We need to join the call for 'slow scholarship' and advocate a re-valuing of feminist and participatory action research approaches, which may have most impact at local level, in order to achieve meaningful shifts in the impact agenda and more broadly, the academy.

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The landfall of Cyclone Catarina on the Brazilian coast in March 2004 became known as the first documented hurricane in the South Atlantic Ocean, promoting a new view oil how large-scale features can contribute to tropical transition. The aim of this paper is to put the large-scale circulation associated with Catarina`s transition in climate perspective. This is discussed in the light of a robust pattern of spatial correlations between thermodynamic and dynamic variables of importance for hurricane formation. A discussion on how transition mechanisms respond to the present-day circulation is presented. These associations help in understanding why Catarina was formed in a region previously thought to be hurricane-free. Catarina developed over a large-scale area of thermodynamically favourable air/sea temperature contrast. This aspect explains the paradox that such a rare system developed when the sea surface temperature was slightly below average. But, although thermodynamics played an important role, it is apparent that Catarina would not have formed without the key dynamic interplay triggered by a high latitude blocking. The blocking was associated with an extreme positive phase of the Southern Annular Mode (SAM) both hemispherically and locally, and the nearby area where Catarina developed is found to be more cyclonic during the positive phase of the SAM. A conceptual model is developed and a `South Atlantic index` is introduced as a useful diagnostic of potential conditions leading to tropical transition in the area, where large-scale indices indicate trends towards more favourable atmospheric conditions for tropical cyclone formation. Copyright (c) 2008 Royal Meteorological Society

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immunodeficiency (CVID), the most common symptomatic primary immunodeficiency in adulthood. Different authors report high prevalences of autoimmune diseases in CVID, and several mechanisms have been proposed to explain this apparent paradox. Genetic predisposition, under current surveillance, innate and adaptive immunity deficiencies leading to persistent/recurrent infections, variable degrees of immune dysregulation, and possible failure in central and peripheral mechanisms of tolerance induction or maintenance may all contribute to increased autoimmunity. Conclusions Data on the clinical/immunological profile of affected patients and treatment are available mostly concerning autoimmune cytopenias, the most common autoimmune diseases in CVID. Treatment is based on conventional alternatives, in association with short experience with new agents, including rituximab and infliximab. Benefits of early immunoglobulin substitutive treatment and hypothetical premature predictors of autoimmunity are discussed as potential improvements to CVID patients` follow-up.

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The study aimed at getting a grass root opinion on poverty and why Ghana is still poor after 50 years of independence in spite of her richness in natural resources, second largest producer of cocoa in the word and appreciable stable political environment. The opinions of the ordinary people in the Bia district and their observed living conditions was analysed in line with theoretical basis of the study and previous studies to justify the stance that poverty should be considered as an abuse of human rights. It was concluded based on position of informants and previous data available that though many factors have been raised by previous scholars as the cause of poverty, the actions and inactions of both internal and external power-holders is the main source of poverty in Ghana. It was proposed that for poverty to be reduced in a sustainable way there should be strong civil society groups and active citizens through civic education to hold power-holders accountable. Until the actions and inactions of power-holders which have subjected many Ghanaians into intergenerational poverty are seen as human rights abuse, the rights of many Ghanaians would be constantly abused. This will eventually defeat the promotion of human rights culture in Ghana.

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A customer is presumed to gravitate to a facility by the distance to it and the attractiveness of it. However regarding the location of the facility, the presumption is that the customer opts for the shortest route to the nearest facility.This paradox was recently solved by the introduction of the gravity p-median model. The model is yet to be implemented and tested empirically. We implemented the model in an empirical problem of locating locksmiths, vehicle inspections, and retail stores ofv ehicle spare-parts, and we compared the solutions with those of the p-median model. We found the gravity p-median model to be of limited use for the problem of locating facilities as it either gives solutions similar to the p-median model, or it gives unstable solutions due to a non-concave objective function.

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Abstract  In a case study about viewing habits in a Swedish audience I sampled 309 questionnaires; interviews with five focus group were conducted together with ten in-depth individual interviews discussing altogether fifteen favorite films exploring specific scenes of idiosyncratic relevance.  The outcome supports claims about viewers as active and playful (cf. Höijer 1998, Frampton 2006, Hoover 2006, Plantinga 2009). In line with mediatization theory I also argue that spiritual meaning making takes place through mediated experiences and I support theories about fiction films as important sources for moral and spiritual reflection (Partridge 2004, Zillman 2005, Lynch 2007, Plantinga 2009). What Hjarvard calls the soft side of mediatization processes (2008) is illustrated showing adults experiencing enchantment through favorite films (Jerslev 2006, Partridge 2008, Klinger 2008, Oliver & Hartmann 2010).  Vernacular meaning making embedded in everyday life and spectators dealing with fiction narratives such as Gladiator, Amelie from Montmartre or Avatar highlights the need for a more nuanced understanding of elevated cinematic experiences. The reported impact of specific movies is analyzed through theories where cognition and affect are central aspects of spectators’ engagements with a film (Tan 1996, Caroll 1999, Grodal 2009). Crucially important are theories of meaning-making where viewers’ detailed interpretation of specific scenes are embedded in high-level meaning-making where world view issues and spectators’ moral frameworks are activated (Zillman 2005, Andersson & Andersson 2005, Frampton 2006, Lynch 2007, Avila 2007, Axelson 2008, Plantinga 2009).  Also results from a growing body of empirical oriented research in film studies are relevant with an interest in what happens with the flesh and blood spectator exposed to filmic narratives (Jerslev 2006, Klinger 2008, Barker 2009, Suckfüll 2010, Oliver & Hartmann 2010). Analyzing the qualitative results of my case study, I want to challenge the claim that the viewer has to suspend higher order reflective cognitive structures in order to experience suture (Butler & Palesh 2004). What I find in my empirical examples is responses related to spectators’ highest levels of mental activity, all anchored in the sensual-emotional apparatus (Grodal 2009). My outcome is in line with a growing number of empirical case studies which support conclusions that both thinking and behavior are affected by film watching (Marsh 2007, Sückfull 2010, Oliver & Hartmann 2010, Axelson forthcoming). The presentation contributes to a development of concepts which combines aesthetic, affective and cognitive components in an investigation of spectator’s moves from emotional evaluation of intra-text narration to extra-textual assessments, testing the narrative for larger significance in idiosyncratic ways (Bordwell & Thompson 1997, Marsh 2007, Johnston 2007, Bruun Vaage 2009, Axelson 2011). There are a several profitable concepts suggested to embrace the complex interplay between affects, cognition and emotions when individuals respond to fictional narratives. Robert K. Johnston label it “deepening gaze” (2007: 307) and “transformative viewing” (2007: 305). Philosopher Mitch Avila proposes “high cognition” (2007: 228) and Casper Thybjerg ”higher meaning” (2008: 60). Torben Grodal talks about “feelings of deep meaning” (Grodal 2009: 149). With a nod to Clifford Geertz, Craig Detweiler adopts “thick description” (2007: 47) as do Kutter Callaway altering it to ”thick interpretations” (Callaway 2013: 203).  Frampton states it in a paradox; ”affective intelligence” (Frampton 2006: 166). As a result of the empirical investigation, inspired by Geertz, Detweiler & Callaway, I advocate thick viewing for capturing the viewing process of these specific moments of film experience when profound and intensified emotional interpretations take place. The author As a sociologist of religion, Tomas Axelsons research deals with people’s use of mediated narratives to make sense of reality in a society characterized by individualization, mediatization and pluralized world views.  He explores uses of fiction film as a resource in every day life and he is currently finishing his three year project funded by the Swedish Research Council: Spectator engagement in film and utopian self-reflexivity. Moving Images and Moved Minds. http://www.du.se/sv/AVM/Personal/Tomas-Axelson Bibliography Axelson, T. (Forthcoming 2014). Den rörliga bildens förmåga att beröra.[1] Stockholm: Liber Axelson, T. (In peer review). Vernacular Meaning Making. Examples of narrative impact in fiction film questioning the ’banal’ notion in mediatization theory. Nordicom Review. Nordicom Göteborg. Axelson, T. (2011). Människans behov av fiktion. Den rörliga bildens förmåga att beröra människan på djupet.[2]Kulturella perspektiv. Volume 2. Article retrieved from www.kultmed.umu.se/digitalAssets/74/74304_axelson-22011.pdf Axelson, Tomas (2010) “Narration, Visualization and Mind. Movies in everyday life as a resource for utopian self-reflection.” Paper presentation at CMRC, 7th Conference of Media, Religion & Culture in Toronto, Canada 9 – 13th August 2010. Axelson, Tomas (2008) Movies and Meaning. Studying Audience, Favourite Films and Existential Matters. Particip@tions : Journal of Audience and Reception Studies. Volume 5, (1). Doctoral dissertation summary. ACTA UNIVERSITATIS UPSALIENSIS. Article retrieved from http://www.participations.org/Volume%205/Issue%201%20-%20special/5_01_axelson.htm  [1] English translation: Moving Images and Moved Minds. [2] English translation: Our need for fiction. Deeply Moved by Moving Images. Cultural Perspectives.