468 research outputs found

    Quantum Mechanics from Symmetry and Statistical Modelling

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    A version of quantum theory is derived from a set of plausible assumptions related to the following general setting: For a given system there is a set of experiments that can be performed, and for each such experiment an ordinary statistical model is defined. The parameters of the single experiments are functions of a hyperparameter, which defines the state of the system. There is a symmetry group acting on the hyperparameters, and for the induced action on the parameters of the single experiment a simple consistency property is assumed, called permissibility of the parametric function. The other assumptions needed are rather weak. The derivation relies partly on quantum logic, partly on a group representation of the hyperparameter group, where the invariant spaces are shown to be in 1-1 correspondence with the equivalence classes of permissible parametric functions. Planck's constant only plays a role connected to generators of unitary group representations

    How to Listen to Pachamama’s Testimonio: Lessons from Indigenous Voices

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    This article analyzes the collective, open-access, and modifiable publication El Vivir Bien como respuesta a la Crisis Global as a posthumanist testimonio or ecotestimonio intending to give voice to the biotic community of the Andes. Written by Quechua and Aymara people and presented to the United Nations by the Plurinational State of Bolivia, this document targets the global ecological, financial, and social crises from the perspective of Indigenous knowledges. This document also exemplifies the worldwide reemergence of Indigenous voices that are confronting the global ecological crisis and its environmental injustices through the revitalization of Indigenous worldviews and practices. This ecotestimonio conveys, among many timely lessons, the Indigenous teaching that humans must listen carefully to the non-human world to learn from Pachamama how to interrelate as humans and with non-humans to collaborate in ensuring the continuing vitality of the community of life. If we listen carefully to Pachamama’s testimony, as Indigenous voices urge, doubt must be cast upon the viability of ideas celebrated by hegemonic Western modern discourses like development, progress, or ‘ economic growth. Instead, these voices invite us to rethink the place, functions, and responsibilities of humans as members of the web of life

    Maintenance of weight loss and aerobic capacity one year aft er the end of a lifestyle intervention focusing on nutritional guidance and/or exercise

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    The aims of this study were to: 1) investigate to what extent participants in a lifestyle intervention program, including nutritional guidance and two weekly intensive running sessions, maintain improvements in aerobic capacity and health parameters one year after the end of an intervention; and 2) identify common determinants for those participants who succeeded in weight loss maintenance. A total of 51 participants completed the 33-week intervention. One year after the end of the intervention period (1YA) 34 participants completed anthropometric measurements, 12 (8 women) in the training group (TG) and 22 (13 women) in the nutritional guidance and training group (NTG). A total of 13 participants (9 women) in the TG and 11 participants (7 women) in the NTG completed a 3000 m running test. There were no significant differences in body mass index, 3000 m running time or waist circumference between the groups 1YA. There was however, substantial variation in both groups as to what extent participants had maintained their weight loss. Higher self-efficacy and self-control in relation to food and exercise characterized those who best maintained their weight loss

    Craft, Community and the Material Culture of Place and Politics, 19th–20th Century

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    Book Review: Craft, Community and the Material Culture of Place and Politics, 19th-20th century Edited by Janice Helland, Beverley Lemire and Alena Buis Ashgate, February 2014; 245pp. 46 b&w illustrations; hardback ÂŁ60.00 ISBN: 978-1-4094-6207-

    Collusion through Joint R&D: An Empirical Assessment

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    This paper tests whether upstream R&D cooperation leads to downstream collusion. We consider an oligopolistic setting where firms enter in research joint ventures (RJVs) to lower production costs or coordinate on collusion in the product market. We show that a sufficient condition for identifying collusive behavior is a decline in the market share of RJV-participating firms, which is also necessary and sufficient for a decrease in consumer welfare. Using information from the US National Cooperation Research Act, we estimate a market share equation correcting for the endogeneity of RJV participation and R&D expenditures. We find robust evidence that large networks between direct competitors – created through firms being members in several RJVs at the same time – are conducive to collusive outcomes in the product market which reduce consumer welfare. By contrast, RJVs among non-competitors are efficiency enhancing

    A frequentist framework of inductive reasoning

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    Reacting against the limitation of statistics to decision procedures, R. A. Fisher proposed for inductive reasoning the use of the fiducial distribution, a parameter-space distribution of epistemological probability transferred directly from limiting relative frequencies rather than computed according to the Bayes update rule. The proposal is developed as follows using the confidence measure of a scalar parameter of interest. (With the restriction to one-dimensional parameter space, a confidence measure is essentially a fiducial probability distribution free of complications involving ancillary statistics.) A betting game establishes a sense in which confidence measures are the only reliable inferential probability distributions. The equality between the probabilities encoded in a confidence measure and the coverage rates of the corresponding confidence intervals ensures that the measure's rule for assigning confidence levels to hypotheses is uniquely minimax in the game. Although a confidence measure can be computed without any prior distribution, previous knowledge can be incorporated into confidence-based reasoning. To adjust a p-value or confidence interval for prior information, the confidence measure from the observed data can be combined with one or more independent confidence measures representing previous agent opinion. (The former confidence measure may correspond to a posterior distribution with frequentist matching of coverage probabilities.) The representation of subjective knowledge in terms of confidence measures rather than prior probability distributions preserves approximate frequentist validity.Comment: major revisio
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