62,575 research outputs found
POVMs and Naimark's theorem without sums
We provide a definition of POVM in terms of abstract tensor structure only.
It is justified in two distinct manners. i. At this abstract level we are still
able to prove Naimark's theorem, hence establishing a bijective correspondence
between abstract POVMs and abstract projective measurements on an extended
system, and this proof is moreover purely graphical. ii. Our definition
coincides with the usual one for the particular case of the Hilbert space
tensor product. We also point to a very useful normal form result for the
classical object structure introduced in quant-ph/0608035
Connected components of compact matrix quantum groups and finiteness conditions
We introduce the notion of identity component of a compact quantum group and
that of total disconnectedness. As a drawback of the generalized Burnside
problem, we note that totally disconnected compact matrix quantum groups may
fail to be profinite. We consider the problem of approximating the identity
component as well as the maximal normal (in the sense of Wang) connected
subgroup by introducing canonical, but possibly transfinite, sequences of
subgroups. These sequences have a trivial behaviour in the classical case. We
give examples, arising as free products, where the identity component is not
normal and the associated sequence has length 1.
We give necessary and sufficient conditions for normality of the identity
component and finiteness or profiniteness of the quantum component group. Among
them, we introduce an ascending chain condition on the representation ring,
called Lie property, which characterizes Lie groups in the commutative case and
reduces to group Noetherianity of the dual in the cocommutative case. It is
weaker than ring Noetherianity but ensures existence of a generating
representation. The Lie property and ring Noetherianity are inherited by
quotient quantum groups. We show that A_u(F) is not of Lie type. We discuss an
example arising from the compact real form of U_q(sl_2) for q<0.Comment: 43 pages. Changes in the introduction. The relation between our and
Wang's notions of central subgroup has been clarifie
Nutritional status and socioeconomic change among Toba and Wichí populations of the Argentinean Chaco
The prevalence of overweight and obesity is growing at an accelerated pace in disadvantaged populations. Indigenous populations all over the world, whose lifestyle is changing rapidly and drastically, seem to be particularly prone to show an increased prevalence of overweight and its co-morbidities among adults. The aim of this study was to evaluate the association between socioeconomic and nutritional statuses in adults of two indigenous populations of the Argentine Gran Chaco: the Toba and Wichí of the province of Formosa. Originally hunter-gatherers, they are now more settled and engage in temporary wage labor and local political positions. A total of 541 adults (>20 years old) participated in the study. Almost 50% of the adult Toba and 34% of the adult Wichí were overweight and 10% of adults in both populations were obese. Socioeconomic status was positively associated with body mass index in both populations. Furthermore, political connectedness with the non-indigenous sector, as in the case of community leaders, was highly correlated with obesity. Differences within and between groups can be explained by biocultural factors that include gender, diet (foraged vs store-bought), lifestyle (sedentary vs more active), and history of political power. Our study highlights the interactions among social, cultural, and political economic variables, such as political hierarchies within the group or degree of social connectedness with community leaders. By making these variables an integral part of our analysis and interpretation, we hope to improve our understanding of the situation of indigenous populations in transition. © 2009 Elsevier B.V. All rights reserved.Fil: Valeggia, Claudia Rita. University of Pennsylvania; Estados UnidosFil: Burke, Kevin M.. University of Pennsylvania; Estados UnidosFil: Fernandez Duque, Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina. University of Pennsylvania; Estados Unido
What's the big idea? A critical exploration of the concept of social capital and its incorporation into leisure policy discourse
Starting from the overwhelming welcome that Putnam's (2000) treatise on social capital has received in government circles, we consider its relative merits for examining and understanding the role for leisure in policy strategies. To perform this critique we identify some of the key points from Putnam's work and also illustrate how it has been incorporated into a body of leisure studies literature. This is then extended to a discussion of the methodological and theoretical underpinnings of his approach and its link to civic communitarianism. We suggest that the seduction of the 'niceness' of Putnam's formulation of social capital not only misses the point of the grimness of some people's lives but it also pays little attention to Bourdieu's point that poorer community groups tend to be at the mercy of forces over which they have little control. We argue that if the poor have become a silent emblem of the ways in which the state has more and more individualised its relationship with its citizens, it is they who also tend to be blamed for their own poverty because it is presumed that they lack social capital. This in turn encourages 'us' to determine what is appropriate for 'them'. As a critical response to this situation, we propose that Bourdieu's take on different forms of 'capital' offers more productive lines for analysis. From there we go on to suggest that it might be profitable to combine Bourdieu's sociology with Sennett's recent interpretation of 'respect' to formulate a central interpretive role for community leisure practitioners - recast as cultural intermediaries - if poorer community groups are to be better included. © 2005 Taylor & Francis Group Ltd
Zipf's law and log-normal distributions in measures of scientific output across fields and institutions: 40 years of Slovenia's research as an example
Slovenia's Current Research Information System (SICRIS) currently hosts
86,443 publications with citation data from 8,359 researchers working on the
whole plethora of social and natural sciences from 1970 till present. Using
these data, we show that the citation distributions derived from individual
publications have Zipfian properties in that they can be fitted by a power law
, with between 2.4 and 3.1 depending on the
institution and field of research. Distributions of indexes that quantify the
success of researchers rather than individual publications, on the other hand,
cannot be associated with a power law. We find that for Egghe's g-index and
Hirsch's h-index the log-normal form
applies best, with and depending moderately on the underlying set of
researchers. In special cases, particularly for institutions with a strongly
hierarchical constitution and research fields with high self-citation rates,
exponential distributions can be observed as well. Both indexes yield
distributions with equivalent statistical properties, which is a strong
indicator for their consistency and logical connectedness. At the same time,
differences in the assessment of citation histories of individual researchers
strengthen their importance for properly evaluating the quality and impact of
scientific output.Comment: 8 pages, 3 figures; accepted for publication in Journal of
Informetrics [supplementary material available at
http://www.matjazperc.com/sicris/stats.html
Conceptualisations of children’s wellbeing at school: the contribution of recognition theory
A large study in Australian schools aimed to elucidate understandings of ‘wellbeing’ and of factors in school life that contribute to it. Students and teachers understood wellbeing primarily, and holistically, in terms of interpersonal relationships, in contrast to policy documents which mainly focused on ‘problem areas’ such as mental health. The study also drew on recognition theory as developed by the social philosopher Axel Honneth. Results indicate that recognition theory may be useful in understanding wellbeing in schools, and that empirical research in schools may give rise to further questions regarding theory
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