4,660 research outputs found

    Equilibrium random-field Ising critical scattering in the antiferromagnet Fe(0.93)Zn(0.07)F2

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    It has long been believed that equilibrium random-field Ising model (RFIM) critical scattering studies are not feasible in dilute antiferromagnets close to and below Tc(H) because of severe non-equilibrium effects. The high magnetic concentration Ising antiferromagnet Fe(0.93)Zn(0.07)F2, however, does provide equilibrium behavior. We have employed scaling techniques to extract the universal equilibrium scattering line shape, critical exponents nu = 0.87 +- 0.07 and eta = 0.20 +- 0.05, and amplitude ratios of this RFIM system.Comment: 4 pages, 1 figure, minor revision

    Some remarks on the GNS representations of topological ^*-algebras

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    After an appropriate restatement of the GNS construction for topological ^*-algebras we prove that there exists an isomorphism among the set \cycl(A) of weakly continuous strongly cyclic ^*-representations of a barreled dual-separable ^*-algebra with unit AA, the space \hilb_A(A^*) of the Hilbert spaces that are continuously embedded in AA^* and are ^*-invariant under the dual left regular action of AA and the set of the corresponding reproducing kernels. We show that these isomorphisms are cone morphisms and we prove many interesting results that follow from this fact. We discuss how these results can be used to describe cyclic representations on more general inner product spaces.Comment: 34 pages. Minor changes. To appear in J. Math. Phys. 49 (4) Apr-0

    Natural regulatory (CD4+CD25+FOXP+) T cells control the production of pro-inflammatory cytokines during Plasmodium chabaudi adami infection and do not contribute to immune evasion.

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    Different functions have been attributed to natural regulatory CD4+CD25+FOXP+ (Treg) cells during malaria infection. Herein, we assessed the role for Treg cells during infections with lethal (DS) and non-lethal (DK) Plasmodium chabaudi adami parasites, comparing the levels of parasitemia, inflammation and anaemia. Independent of parasite virulence, the population of splenic Treg cells expanded during infection, and the absolute numbers of activated CD69+ Treg cells were higher in DS-infected mice. In vivo depletion of CD25+ T cells, which eliminated 80% of CD4+FOXP3+CD25+ T cells and 60–70% of CD4+FOXP3+ T cells, significantly decreased the number of CD69+ Treg cells in mice with lethal malaria. As a result, higher parasite burden and morbidity were measured in the latter, whereas the kinetics of infection with non-lethal parasites remained unaffected. In the absence of Treg cells, parasite-specific IFN-γ responses by CD4+ T cells increased significantly, both in mice with lethal and non-lethal infections, whereas IL-2 production was only stimulated in mice with non-lethal malaria. Following the depletion of CD25+ T cells, the production of IL-10 by CD90− cells was also enhanced in infected mice. Interestingly, a potent induction of TNF- and IFN-γ production by CD4+ and CD90− lymphocytes was measured in DS-infected mice, which also suffered severe anaemia earlier than non-depleted infected controls. Taken together, our data suggest that the expansion and activation of natural Treg cells represent a counter-regulatory response to the overwhelming inflammation associated with lethal P.c. adami. This response to infection involves TH1 lymphocytes as well as cells from the innate immune system

    Review: A Pedagogy of Powerful Communication: Youth Radio and Radio Arts in the Multilingual Classroom

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    In this review of Dana Walker\u27s 2014 book A Pedagogy of Powerful Communication: Youth Radio and Radio Arts in the Multilingual Classroom, Jillian Belanger recounts the project\u27s four main aims of media production, community engagement, student confidence, and language development, and offers insight to what made Walker\u27s work engaging English Learners with youth radio production a success, including recommendations for how her findings might be replicated in other environments

    Motives and characteristics of gift-giving at the University of Nevada, Las Vegas

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    Public institutions of higher learning need to increase reliance on private financial support for a portion of their revenue stream due to decreases in public financial support and increases in institutional needs. To help meet university demands for private funding, fundraising bodies, such as university foundations, need to target their limited resources in directions that will yield the greatest financial results. One way to do this is to identify individuals who are more likely to provide monetary gifts to the university and target fundraising efforts toward them; The purpose of this study was to build a predictive model that was based on the motives and characteristics of gift-giving by the University of Nevada, Las Vegas alumni. The study would determine the relationship among these variables to the level of gift-giving. In total, 18 variables were selected and used in this study; Descriptive statistics were use to demonstrate the frequency distribution and the measure of central tendency for each variable being studied. The relationships among various variables to the level of gift-giving were determined by utilizing artificial neural network technology. This study was delimited to a sample of the total population of over 35,000 alumni at the University of Nevada, Las Vegas. The sample consisted of three study groups: (1) a sub-sample of alumni who contributed {dollar}10 to {dollar}1,000 at least one time, (2) a sub-sample of alumni who were non-contributors, and (3) all alumni who contributed over {dollar}1,000 at least one time; Overall, the study demonstrated that there were small differences between the three study groups. There is little evidence to support the ability to predict gift-giving at various levels of giving, using the motives and characteristics that were under review in this study. There is moderate predictive ability, in terms of repeat giving for contributors of over {dollar}1,000, with six predictive variables: the academic college from which one has received their degree, the number of years following graduation before giving for the first time, the desire for a tax deduction, the amount contributed, giving to another higher educational institution, and marital status

    Light mixed sneutrinos as thermal dark matter

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    In supersymmetric models with Dirac neutrino masses, a left-right mixed sneutrino can be a viable dark matter candidate. We examine the MSSM+ν~R\tilde\nu_R parameter space where this is the case with particular emphasis on light sneutrinos with masses below 10 GeV. We discuss implications for direct and indirect dark matter searches, including the relevant uncertainties, as well as consequences for collider phenomenology.Comment: 33 pages, 14 figures; one figure and references adde

    Nonequilibrium phase transitions and tricriticality in a three-dimensional lattice system with random-field competing kinetics

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    We study a nonequilibrium Ising model that stochastically evolves under the simultaneous operation of several spin-flip mechanisms. In other words, the local magnetic fields change sign randomly with time due to competing kinetics. This dynamics models a fast and random diffusion of disorder that takes place in dilute metallic alloys when magnetic ions diffuse. We performe Monte Carlo simulations on cubic lattices up to L=60. The system exhibits ferromagnetic and paramagnetic steady states. Our results predict first-order transitions at low temperatures and large disorder strengths, which correspond to the existence of a nonequilibrium tricritical point at finite temperature. By means of standard finite-size scaling equations, we estimate the critical exponents in the low-field region, for which our simulations uphold continuous phase transitions.Comment: 14 pages, 7 figures, accepted for publication in Phys. Rev.

    Genome-wide linkage scan for loci associated with epilepsy in Belgian shepherd dogs.

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    BackgroundIdiopathic epilepsy in the Belgian shepherd dog is known to have a substantial genetic component. The objective of this study was to identify genomic regions associated with the expression of generalized seizures in the Belgian Tervuren and Sheepdog.ResultsDNA from 366 dogs, of which 74 were classified as epileptic, representing two extended families were subjected to a genome-wide linkage scan using 410 microsatellite markers yielding informative coverage averaging 5.95 +/- 0.21 Mb. Though previous studies based on pedigree analyses proposed a major gene of influence, the present study demonstrated the trait to be highly polygenic. Studies of complex disorders in humans indicate that a liberal composite evaluation of genetic linkage is needed to identify underlying quantitative trait loci (QTLs). Four chromosomes yielded tentative linkage based upon LOD scores in excess of 1.0. Possible QTLs within these regions were supported also by analyses of multipoint linkage, allele frequency, TDT, and transmission of haplotype blocks.ConclusionsTaken together the data tentatively indicate six QTLs, three on CFA 2, and one on each of CFA 6, 12, and 37, that support fine mapping for mutations associated with epilepsy in the Belgian shepherd. The study also underscores the complexity of genomic linkage studies for polygenic disorders

    Singular point characterization in microscopic flows

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    We suggest an approach to microrheology based on optical traps in order to measure fluid fluxes around singular points of fluid flows. We experimentally demonstrate this technique, applying it to the characterization of controlled flows produced by a set of birefringent spheres spinning due to the transfer of light angular momentum. Unlike the previous techniques, this method is able to distinguish between a singular point in a complex flow and the absence of flow at all; furthermore it permits us to characterize the stability of the singular point.Comment: 4 pages and 4 figure
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