59,287 research outputs found

    Hearing the grass grow. Emotional and epistemological challenges of practice-near research

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    This paper discusses the concept of practice-near research in terms of the emotional and epistemological challenges that arise from the researcher coming 'near' enough to other people for psychological processes to ensue. These may give rise in the researcher to confusion, anxiety and doubt about who is who and what is what; but also to the possibility of real emotional and relational depth in the research process. Using illustrations from three social work doctoral research projects undertaken by students at the Tavistock Clinic and the University of East London the paper examines four themes that seem to the author to be central to meaningful practice-near research undertaken in a spirit of true emotional and epistemological open-mindedness: the smell of the real; losing our minds; the inevitability of personal change; and the discovery of complex particulars

    Robustness of Fractional Quantum Hall States with Dipolar Atoms in Artificial Gauge Fields

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    The robustness of fractional quantum Hall states is measured as the energy gap separating the Laughlin ground-state from excitations. Using thermodynamic approximations for the correlation functions of the Laughlin state and the quasihole state, we evaluate the gap in a two-dimensional system of dipolar atoms exposed to an artificial gauge field. For Abelian fields, our results agree well with the results of exact diagonalization for small systems, but indicate that the large value of the gap predicted in [Phys. Rev. Lett. 94, 070404 (2005)] was overestimated. However, we are able to show that the small gap found in the Abelian scenario is dramatically increased if we turn to non-Abelian fields squeezing the Landau levels

    Developing the Next Generation of Physics Assessments

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    Science education at all levels is currently undergoing dramatic changes to its curricula and developing assessments for these new curricula is paramount. We have used the basis of many of these new changes (scientific practices, crosscutting concepts, and core ideas) to develop sets of criteria that can be used to guide assessment development for this new curriculum. We present a case study that uses the criteria we have developed to revise a traditional physics assessment item into an assessment item that is much more aligned with the goals of current transformation efforts. Assessment items developed using this criteria can be used to assess student learning of both the concepts and process of science.Comment: Revised version for PERC 2015 Conference Proceeding

    Vacuum Structure of Two-Dimensional ϕ4\phi^4 Theory on the Orbifold S1/Z2S^{1}/Z_{2}

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    We consider the vacuum structure of two-dimensional ϕ4\phi^4 theory on S1/Z2S^{1}/Z_{2} both in the bosonic and the supersymmetric cases. When the size of the orbifold is varied, a phase transition occurs at Lc=2π/mL_{c}=2\pi/m, where mm is the mass of ϕ\phi. For L<LcL<L_{c}, there is a unique vacuum, while for L>LcL>L_{c}, there are two degenerate vacua. We also obtain the 1-loop quantum corrections around these vacuum solutions, exactly in the case of L<LcL<L_{c} and perturbatively for LL greater than but close to LcL_{c}. Including the fermions we find that the "chiral" zero modes around the fixed points are different for LLcLL_{c}. As for the quantum corrections, the fermionic contributions cancel the singular part of the bosonic contributions at L=0. Then the total quantum correction has a minimum at the critical length LcL_{c}.Comment: Revtex, 15 pages, 3 eps figure

    Optical sum rules that relate to the potential energy of strongly correlated systems

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    A class of sum rules for inelastic light scattering is developed. We show that the first moment of the non-resonant response provides information about the potential energy in strongly correlated systems. The polarization dependence of the sum rules provide information about the electronic excitations in different regions of the Brillouin zone. We determine the sum rule for the Falicov-Kimball model, which possesses a metal-insulator transition, and compare our results to the light scattering experiments in SmB_6.Comment: (5 pages, 3 figures, typeset in ReVTeX

    Structural and electrostatic effects at the surfaces of size- and charge-selected aqueous nanodrops.

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    The effects of ion charge, polarity and size on the surface morphology of size-selected aqueous nanodrops containing a single ion and up to 550 water molecules are investigated with infrared photodissociation (IRPD) spectroscopy and theory. IRPD spectra of M(H2O) n where M = La3+, Ca2+, Na+, Li+, I-, SO42- and supporting molecular dynamics simulations indicate that strong interactions between multiply charged ions and water molecules can disrupt optimal hydrogen bonding (H-bonding) at the nanodrop surface. The IRPD spectra also reveal that "free" OH stretching frequencies of surface-bound water molecules are highly sensitive to the ion's identity and the OH bond's local H-bond environment. The measured frequency shifts are qualitatively reproduced by a computationally inexpensive point-charge model that shows the frequency shifts are consistent with a Stark shift from the ion's electric field. For multiply charged cations, pronounced Stark shifting is observed for clusters containing ∼100 or fewer water molecules. This is attributed to ion-induced solvent patterning that extends to the nanodrop surface, and serves as a spectroscopic signature for a cation's ability to influence the H-bond network of water located remotely from the ion. The Stark shifts measured for the larger nanodrops are extrapolated to infinite dilution to obtain the free OH stretching frequency of a surface-bound water molecule at the bulk air-water interface (3696.5-3701.0 cm-1), well within the relatively wide range of values obtained from SFG measurements. These cluster measurements also indicate that surface curvature effects can influence the free OH stretching frequency, and that even nanodrops without an ion have a surface potential that depends on cluster size

    Helminth infections, atopy, asthma and allergic diseases: protocol for a systematic review of observational studies worldwide.

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    INTRODUCTION: Childhood infections, particularly those caused by helminths are considered to be important environmental exposures influencing the development of allergic diseases. However, epidemiological studies focusing on the relationship between helminth infections and risk of allergic diseases, performed worldwide, show inconsistent findings. Previous systematic reviews of observational studies published 10 or more years ago showed conflicting findings for effects of helminths on allergic diseases. Over the past 10 years there has been growing literature addressing this research area and these need to be considered in order to appreciate the most contemporary evidence. The objective of the current systematic review will be to provide an up-to-date synthesis of findings of observational studies investigating the influence of helminth infections on atopy, and allergic diseases. METHODS AND ANALYSIS: This systematic review protocol was registered at PROSPERO. We will search Cochrane Library, MEDLINE, EMBASE, CINAHL, AMED, ISI Web of Science, WHO Global Health Library, Scielo, IndMed, PakMediNet, KoreaMed, Ichushi for published studies from 1970 to January 2020. Bibliographies of all eligible studies will be reviewed to identify additional studies. Unpublished and ongoing research will also be searched in key databases. There will be no language or geographical restrictions regarding publications. Critical Appraisal Skills Programme quality assessment tool will be used to appraise methodological quality of included studies. A descriptive summary with data tables will be constructed, and if adequate, meta-analysis using random-effects will be performed. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist will be followed for reporting of the systematic review. ETHICS AND DISSEMINATION: Since this systematic review will be only based on published and retrievable literature, no ethics approval will be sought. The multidisciplinary team performing this systematic review will participate in relevant dissemination activities. Findings will be presented at scientific meetings and publish the systematic review in international, peer-reviewed, open-access journals. PROSPERO REGISTRATION NUMBER: CRD42020167249
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