936 resultados para Higher order terms
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Retreating ice fronts (as a result of a warming climate) expose large expanses of deglaciated forefield, which become colonized by microbes and plants. There has been increasing interest in characterizing the biogeochemical development of these ecosystems using a chronosequence approach. Prior to the establishment of plants, microbes use autochthonously produced and allochthonously delivered nutrients for growth. The microbial community composition is largely made up of heterotrophic microbes (both bacteria and fungi), autotrophic microbes and nitrogen-fixing diazotrophs. Microbial activity is thought to be responsible for the initial build-up of labile nutrient pools, facilitating the growth of higher order plant life in developed soils. However, it is unclear to what extent these ecosystems rely on external sources of nutrients such as ancient carbon pools and periodic nitrogen deposition. Furthermore, the seasonal variation of chronosequence dynamics and the effect of winter are largely unexplored. Modelling this ecosystem will provide a quantitative evaluation of the key processes and could guide the focus of future research. Year-round datasets combined with novel metagenomic techniques will help answer some of the pressing questions in this relatively new but rapidly expanding field, which is of growing interest in the context of future large-scale ice retreat.
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This article critically reflects on the widely held view of a causal chain with trust in public authorities impacting technology acceptance via perceived risk. It first puts forward conceptual reason against this view, as the presence of risk is a precondition for trust playing a role in decision making. Second, results from consumer surveys in Italy and Germany are presented that support the associationist model as counter hypothesis. In that view, trust and risk judgments are driven by and thus simply indicators of higher order attitudes toward a certain technology which determine acceptance instead. The implications of these findings are discussed.
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It has been postulated that autism spectrum disorder is underpinned by an ‘atypical connectivity’ involving higher-order association brain regions. To test this hypothesis in a large cohort of adults with autism spectrum disorder we compared the white matter networks of 61 adult males with autism spectrum disorder and 61 neurotypical controls, using two complementary approaches to diffusion tensor magnetic resonance imaging. First, we applied tract-based spatial statistics, a ‘whole brain’ non-hypothesis driven method, to identify differences in white matter networks in adults with autism spectrum disorder. Following this we used a tract-specific analysis, based on tractography, to carry out a more detailed analysis of individual tracts identified by tract-based spatial statistics. Finally, within the autism spectrum disorder group, we studied the relationship between diffusion measures and autistic symptom severity. Tract-based spatial statistics revealed that autism spectrum disorder was associated with significantly reduced fractional anisotropy in regions that included frontal lobe pathways. Tractography analysis of these specific pathways showed increased mean and perpendicular diffusivity, and reduced number of streamlines in the anterior and long segments of the arcuate fasciculus, cingulum and uncinate—predominantly in the left hemisphere. Abnormalities were also evident in the anterior portions of the corpus callosum connecting left and right frontal lobes. The degree of microstructural alteration of the arcuate and uncinate fasciculi was associated with severity of symptoms in language and social reciprocity in childhood. Our results indicated that autism spectrum disorder is a developmental condition associated with abnormal connectivity of the frontal lobes. Furthermore our findings showed that male adults with autism spectrum disorder have regional differences in brain anatomy, which correlate with specific aspects of autistic symptoms. Overall these results suggest that autism spectrum disorder is a condition linked to aberrant developmental trajectories of the frontal networks that persist in adult life.
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We study compressible magnetohydrodynamic turbulence, which holds the key to many astrophysical processes, including star formation and cosmic-ray propagation. To account for the variations of the magnetic field in the strongly turbulent fluid, we use wavelet decomposition of the turbulent velocity field into Alfven, slow, and fast modes, which presents an extension of the Cho & Lazarian decomposition approach based on Fourier transforms. The wavelets allow us to follow the variations of the local direction of the magnetic field and therefore improve the quality of the decomposition compared to the Fourier transforms, which are done in the mean field reference frame. For each resulting component, we calculate the spectra and two-point statistics such as longitudinal and transverse structure functions as well as higher order intermittency statistics. In addition, we perform a Helmholtz-Hodge decomposition of the velocity field into incompressible and compressible parts and analyze these components. We find that the turbulence intermittency is different for different components, and we show that the intermittency statistics depend on whether the phenomenon was studied in the global reference frame related to the mean magnetic field or in the frame defined by the local magnetic field. The dependencies of the measures we obtained are different for different components of the velocity; for instance, we show that while the Alfven mode intermittency changes marginally with the Mach number, the intermittency of the fast mode is substantially affected by the change.
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We investigated whether variants in major candidate genes for food intake and body weight regulation contribute to obesity-related traits under a multilocus perspective. We studied 375 Brazilian subjects from partially isolated African-derived populations (quilombos). Seven variants displaying conflicting results in previous reports and supposedly implicated in the susceptibility of obesity-related phenotypes were investigated: beta(2)-adrenergic receptor (ADRB2) (Arg16Gly), insulin induced gene 2 (INSIG2) (rs7566605), leptin (LEP) (A19G), LEP receptor (LEPR) (Gln223Arg), perilipin (PLIN) (6209T > C), peroxisome proliferator-activated receptor-gamma (PPARG) (Pro12Ala), and resistin (RETN) (-420C > G). Regression models as well as generalized multifactor dimensionality reduction (GMDR) were employed to test the contribution of individual effects and higher-order interactions to BMI and waist-hip ratio (WHR) variation and risk of overweight/obesity. The best multilocus association signal identified in the quilombos was further examined in an independent sample of 334 Brazilian subjects of European ancestry. In quilombos, only the PPARG polymorphism displayed significant individual effects (WHR variation, P = 0.028). No association was observed either with the risk of overweight/obesity (BMI >= 25 kg/m(2)), risk of obesity alone (BMI >= 30 kg/m(2)) or BMI variation. However, GMDR analyses revealed an interaction between the LEPR and ADRB2 polymorphisms (P = 0.009) as well as a third-order effect involving the latter two variants plus INSIG2 (P = 0.034) with overweight/obesity. Assessment of the LEPR-ADRB2 interaction in the second sample indicated a marginally significant association (P = 0.0724), which was further verified to be limited to men (P = 0.0118). Together, our findings suggest evidence for a two-locus interaction between the LEPR Gln223Arg and ADRB2 Arg16Gly variants in the risk of overweight/obesity, and highlight further the importance of multilocus effects in the genetic component of obesity.
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It is shown that in quantum gravity at finite temperature, the effective potential evaluated in the tadpole approximation can have a local minimum below a certain critical temperature. However, when the leading higher order thermal loop corrections are included, one finds that no static solution exists at high temperature. (C) 2008 Elsevier B.V. All rights reserved.
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We prove the semi-Riemannian bumpy metric theorem using equivariant variational genericity. The theorem states that, on a given compact manifold M, the set of semi-Riemannian metrics that admit only nondegenerate closed geodesics is generic relatively to the C(k)-topology, k=2, ..., infinity, in the set of metrics of a given index on M. A higher-order genericity Riemannian result of Klingenberg and Takens is extended to semi-Riemannian geometry.
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Quadratic assignment problems (QAPs) are commonly solved by heuristic methods, where the optimum is sought iteratively. Heuristics are known to provide good solutions but the quality of the solutions, i.e., the confidence interval of the solution is unknown. This paper uses statistical optimum estimation techniques (SOETs) to assess the quality of Genetic algorithm solutions for QAPs. We examine the functioning of different SOETs regarding biasness, coverage rate and length of interval, and then we compare the SOET lower bound with deterministic ones. The commonly used deterministic bounds are confined to only a few algorithms. We show that, the Jackknife estimators have better performance than Weibull estimators, and when the number of heuristic solutions is as large as 100, higher order JK-estimators perform better than lower order ones. Compared with the deterministic bounds, the SOET lower bound performs significantly better than most deterministic lower bounds and is comparable with the best deterministic ones.
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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.
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In this paper we describe our system for automatically extracting "correct" programs from proofs using a development of the Curry-Howard process. Although program extraction has been developed by many authors, our system has a number of novel features designed to make it very easy to use and as close as possible to ordinary mathematical terminology and practice. These features include 1. the use of Henkin's technique to reduce higher-order logic to many-sorted (first-order) logic; 2. the free use of new rules for induction subject to certain conditions; 3. the extensive use of previously programmed (total, recursive) functions; 4. the use of templates to make the reasoning much closer to normal mathematical proofs and 5. a conceptual distinction between the computational type theory (for representing programs)and the logical type theory (for reasoning about programs). As an example of our system we give a constructive proof of the well known theorem that every graph of even parity, which is non-trivial in the sense that it does not consist of isolated vertices, has a cycle. Given such a graph as input, the extracted program produces a cycle as promised.
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In this paper we present an approach to information flow analysis for a family of languages. We start with a simple imperative language. We present an information flow analysis using a flow logic. The paper contains detailed correctness proofs for this analysis. We next extend the analysis to a restricted form of Idealised Algol, a call-by-value higher-order extension of the simple imperative language (the key restriction being the lack of recursion). The paper concludes with a discussion of further extensions, including a probabilistic extension of Idealised Algol.
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John Rawls’s A Theory of Justice (1971), his first major work articulating his theory of justice as fairness, was immediately recognized as a fundamental contribution to political philosophy in the twentieth century. Working within the tradition established by previous philosophers such as Kant and Locke, Rawls employed the contract theory approach. Taking it to a higher order of abstraction, he sought to determine not what the structure of social organization would be, but what the principles which governed social institutions would be under a hypothetical contracting situation. Rawls uses this contract theory approach to construct a society in which the morally irrelevant contingencies of nature and social arrangements are mitigated by principles of justice which govern the basic institutions of society. A common observation has been that Rawls left out any discussion of health care and how it might fit into his conception of a just society. Several philosophers have articulated expansions of the theory to account for health care. In the chapters that follow I will continue this tradition and consider how justice as fairness might be expanded to account for just health care allocation. In doing so, I hope to answer a particularly strong critique of the theory brought up by Amartya Sen and Martha Nussbaum, and to argue for a broadened conception of health care which takes into account the complex causal relationship between society and human health.
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Nesta tese estudamos as derivações de ordem superior (DOS) em anéis não-comutativos. Inicialmente, mostramos que toda derivação tripla de Jordan de ordem superior em um anel semiprimo livre de 2-torção é uma DOS. Em particular, toda derivação de Jordan de ordem superior (DJOS) num anel deste tipo é uma DOS. Estendemos também o resultado a ideais de Lie U, provando que se R é um anel primo livre de 2-torção e D é uma DJOS de U em R onde U ct Z(R) é tal que U2E U para todo u E U, então D é uma DOS de U em R. Nestas condições, se U C Z(R), então o resultado não é válido. Estudamos ainda as DOS cujas componentes satisfazem relações de dependência linear sobre R ou Q (o anel de quocientes à direita de M artindale de R). Caracterizamos tais DOS, e mostramos que as relações de dependência linear são preservadas ao estendermos uma DOS de R a Q.