1,009 research outputs found

    CONTINGENT VALUATION FOCUS GROUPS: INSIGHTS FROM ETHNOGRAPHIC INTERVIEW TECHNIQUES

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    Despite the many important uses (and potential abuses) of focus groups in survey design, the CV literature presents few guidelines to aid moderators in their interaction with focus group participants. This paper draws on the theory and practice of ethnographic interviewing to introduce general guidelines that can improve focus groups as an aid to CV research. The proposed guidelines illustrate types of questions that should reduce speculation and moderator-introduced bias in focus group responses, and improve the correspondence between focus group responses and actual behavior. The paper illustrates these ethnographic guidelines through a CV application concerning watershed resources.Research Methods/ Statistical Methods,

    Theoretical Limits on the Threshold for the Response of Long Cells to Weak Extremely Low Frequency Electric Fields Due to Ionic and Molecular Flux Rectification

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    AbstractUnderstanding exposure thresholds for the response of biological systems to extremely low frequency (ELF) electric and magnetic fields is a fundamental problem of long-standing interest. We consider a two-state model for voltage-gated channels in the membrane of an isolated elongated cell (Lcell=1mm; rcell=25μm) and use a previously described process of ionic and molecular flux rectification to set lower bounds for a threshold exposure. A key assumption is that it is the ability of weak physical fields to alter biochemistry that is limiting, not the ability of a small number of molecules to alter biological systems. Moreover, molecular shot noise, not thermal voltage noise, is the basis of threshold estimates. Models with and without stochastic resonance are used, with a long exposure time, texp=104 s. We also determined the dependence of the threshold on the basal transport rate. By considering both spherical and elongated cells, we find that the lowest bound for the threshold is Emin ≈ 9×10−3 V m−1 (9×10−5 V cm−1). Using a conservative value for the loop radius rloop=0.3m for induced current, the corresponding lower bound in the human body for a magnetic field exposure is Bmin ≈ 6×10−4 T (6G). Unless large, organized, and electrically amplifying multicellular systems such as the ampullae of Lorenzini of elasmobranch fish are involved, these results strongly suggest that the biophysical mechanism of voltage-gated macromolecules in the membranes of cells can be ruled out as a basis of possible effects of weak ELF electric and magnetic fields in humans

    Characterising competitive equilibrium in terms of opportunity

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    This paper analyses alternative profiles of opportunity sets for individuals in an exchange economy, without assuming that individuals’ choices reveal coherent preferences. It introduces the concept of a ‘market-clearing single-price regime’, representing a profile of opportunity sets consistent with competitive equilibrium. It also proposes an opportunity-based normative criterion, the Strong Opportunity Criterion, which is analogous with the core in preference-based analysis. It shows that every market-clearing single-price regime satisfies the Strong Opportunity Criterion and that, in the limit as an economy is replicated, only such regimes have this property

    Characterization of mouse orofacial pain and the effects of lesioning TRPV1-expressing neurons on operant behavior

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    <p>Abstract</p> <p>Background</p> <p>Rodent models of orofacial pain typically use methods adapted from manipulations to hind paw; however, limitations of these models include animal restraint and subjective assessments of behavior by the experimenter. In contrast to these methods, assessment of operant responses to painful stimuli has been shown to overcome these limitations and expand the breadth of interpretation of the behavioral responses. In the current study, we used an operant model based on a reward-conflict paradigm to assess nociceptive responses in three strains of mice (SKH1-Hr<sup>hr</sup>, C57BL/6J, TRPV1 knockout). We previously validated this operant model in rats and hypothesized in this study that wild-type mice would demonstrate a similar thermal stimulus-dependent response and similar operant pain behaviors. Additionally, we evaluated the effects on operant behaviors of mice manipulated genetically (e.g., TRPV1 k.o.) or pharmacologically with resiniferatoxin (RTX), a lesioning agent for TRPV1-expressing neurons. During the reward-conflict task, mice accessed a sweetened milk reward solution by voluntarily position their face against a neutral or heated thermode (37–55°C).</p> <p>Results</p> <p>As the temperature of the thermal stimulus became noxiously hot, reward licking events in SKH1-Hr<sup>hr </sup>and C57BL/6J mice declined while licking events in TRPV1 k.o. mice were insensitive to noxious heat within the activation range of TRPV1 (37–52°C). All three strains displayed nocifensive behaviors at 55°C, as indicated by a significant decrease in reward licking events. Induction of neurogenic inflammation by topical application of capsaicin reduced licking events in SKH1-Hr<sup>hr </sup>mice, and morphine rescued this response. Again, these results parallel what we previously documented using rats in this operant system. Following intracisternal treatment with RTX, C57BL/6J mice demonstrated a block of noxious heat at both 48 and 55°C. RTX-treated TRPV1 k.o. mice and all vehicle-treated mice displayed similar reward licking events as compared to the pre-treatment baseline levels. Both TRPV1 k.o. and RTX-treated C57BL/6J had complete abolishment of eye-wipe responses following corneal application of capsaicin.</p> <p>Conclusion</p> <p>Taken together, these results indicate the benefits of using the operant test system to investigate pain sensitivity in mice. This ability provides an essential step in the development of new treatments for patients suffering from orofacial pain disorders.</p

    A Frame-Based Language in Information Retrieval

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    With the advent of the information society, many researchers are turning to artificial intelligence techniques to provide effective retrieval over large bodies of textual information. Yet any AI system requires a formalism for encoding its knowledge about the objects of its knowledge, the world, and the intelligence that it is designed to manifest. In the CODER system, the mission of which is to provide an environment for experiments in applying AI to information retrieval, that formalism is provided by a single well defined factual representation language. Designed as a flexible tool for retrieval research, the CODER factual representation language is a hybrid AI language involving a system of strong types for attribute values, a frame system, and a system of Prolog-like relational structures. Inheritance is enforced throughout, and the semantics of type subsumption and object matching formally defined. A collection of type and object managers called the knowledge administration complex implements this common language for storing knowledge and communicating it within the system. Of the three types of knowledge structures in the language, the frame facility has proven most useful in the retrieval domain. The factual representation language is implemented in Prolog as a set of predicates accessible to all system modules. Each level of knowledge representation (elementary primitives, frames, and relations) has a type manager; the frame and relation levels also have object managers. Storage of complete knowledge objects (statements in the factual representation language) is supported by a system or external knowledge bases. One paper discusses the frame construct itself, the implementation of the knowledge administration complex and external knowledge bases. and the use of the construct in retrieval research. The paper closes with a discussion of the utility of the language in experiments

    The clustering of Galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey : including covariance matrix errors

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    JP acknowledges support from the UK Science & Technology Facilities Council (STFC) through the consolidated grant ST/K0090X/1 and from the European Research Council through the ‘Starting Independent Research’ grant 202686, MDEPUGS. AGS acknowledges support from the Trans-regional Collaborative Research Centre TR33 ‘The Dark Universe’ of the German Research Foundation (DFG).We present improved methodology for including covariance matrices in the error budget of Baryon Oscillation Spectroscopic Survey (BOSS) galaxy clustering measurements, revisiting Data Release 9 (DR9) analyses, and describing a method that is used in DR10/11 analyses presented in companion papers. The precise analysis method adopted is becoming increasingly important, due to the precision that BOSS can now reach: even using as many as 600 mock catalogues to estimate covariance of two-point clustering measurements can still lead to an increase in the errors of ∼20 per cent, depending on how the cosmological parameters of interest are measured. In this paper, we extend previous work on this contribution to the error budget, deriving formulae for errors measured by integrating over the likelihood, and to the distribution of recovered best-fitting parameters fitting the simulations also used to estimate the covariance matrix. Both are situations that previous analyses of BOSS have considered. We apply the formulae derived to baryon acoustic oscillation (BAO) and redshift-space distortion (RSD) measurements from BOSS in our companion papers. To further aid these analyses, we consider the optimum number of bins to use for two-point measurements using the monopole power spectrum or correlation function for BAO, and the monopole and quadrupole moments of the correlation function for anisotropic-BAO and RSD measurements.Publisher PDFPeer reviewe

    Anesthesia and Cognitive Performance in Children: No Evidence for a Causal Relationship. Are The Conclusions Justified By The Data?

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    CALL FOR ESSAYS for a volume on Asian Religions for a series titled Women and Religion in the World. This set explores the experiences of women and how their daily lives interface with a dynamic aspect of life and culture, that of religion. The design of this multi-volume, interdisciplinary work depicts a representation of contemporary selected experiences of women in six categories: Judaism, Christianity, Islam, Asian Religions, Indigenous Religions, and New Religions. The themes of (1) Woma..
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