5,796 research outputs found

    Fractional exclusion and braid statistics in one dimension: a study via dimensional reduction of Chern-Simons theory

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    The relation between braid and exclusion statistics is examined in one-dimensional systems, within the framework of Chern-Simons statistical transmutation in gauge invariant form with an appropriate dimensional reduction. If the matter action is anomalous, as for chiral fermions, a relation between braid and exclusion statistics can be established explicitly for both mutual and nonmutual cases. However, if it is not anomalous, the exclusion statistics of emergent low energy excitations is not necessarily connected to the braid statistics of the physical charged fields of the system. Finally, we also discuss the bosonization of one-dimensional anyonic systems through T-duality.Comment: 19 pages, fix typo

    Search for Zs1+Z^{+}_{s1} and Zs2+Z^{+}_{s2} strangeonium-like structures

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    Theoretically, it has been presumed from an effective Lagrangian calculation that there could exist two charged strangeonium-like molecular states Zs1+Z^{+}_{s1} and Zs2+Z^{+}_{s2}, with KKˉK\bar{K}^{*} and KKˉK^{*}\bar{K}^{*} configurations respectively. In the framework of QCD sum rules, we predict that masses of Zs1+Z^{+}_{s1} (KKˉK\bar{K}^{*}) and Zs2+Z^{+}_{s2} (KKˉK^{*}\bar{K}^{*}) are 1.85±0.14GeV1.85\pm0.14 GeV and 2.02±0.15GeV2.02\pm0.15 GeV respectively, which are both above their respective two meson thresholds. We suggest to put in practice the search for these two charged strangeonium-like structures in future experiments.Comment: 7 pages, 4 eps figures; the version accepted for publication in PRD. arXiv admin note: text overlap with arXiv:1203.070

    Molecular wires acting as quantum heat ratchets

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    We explore heat transfer in molecular junctions between two leads in the absence of a finite net thermal bias. The application of an unbiased, time-periodic temperature modulation of the leads entails a dynamical breaking of reflection symmetry, such that a directed heat current may emerge (ratchet effect). In particular, we consider two cases of adiabatically slow driving, namely (i) periodic temperature modulation of only one lead and (ii) temperature modulation of both leads with an ac driving that contains a second harmonic, thus generating harmonic mixing. Both scenarios yield sizeable directed heat currents which should be detectable with present techniques. Adding a static thermal bias, allows one to compute the heat current-thermal load characteristics which includes the ratchet effect of negative thermal bias with positive-valued heat flow against the thermal bias, up to the thermal stop-load. The ratchet heat flow in turn generates also an electric current. An applied electric stop-voltage, yielding effective zero electric current flow, then mimics a solely heat-ratchet-induced thermopower (``ratchet Seebeck effect''), although no net thermal bias is acting. Moreover, we find that the relative phase between the two harmonics in scenario (ii) enables steering the net heat current into a direction of choice.Comment: 9 pages, 8 figure

    Centrality, system size and energy dependences of charged-particle pseudo-rapidity distribution

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    Utilizing the three-fireball picture within the quark combination model, we study systematically the charged particle pseudorapidity distributions in both Au+Au and Cu+Cu collision systems as a function of collision centrality and energy, sNN=\sqrt{s_{NN}}= 19.6, 62.4, 130 and 200 GeV, in full pseudorapidity range. We find that: (i)the contribution from leading particles to dNch/dηdN_{ch}/d\eta distributions increases with the decrease of the collision centrality and energy respectively; (ii)the number of the leading particles is almost independent of the collision energy, but it does depend on the nucleon participants NpartN_{part}; (iii)if Cu+Cu and Au+Au collisions at the same collision energy are selected to have the same NpartN_{part}, the resulting of charged particle dN/dηdN/d\eta distributions are nearly identical, both in the mid-rapidity particle density and the width of the distribution. This is true for both 62.4 GeV and 200 GeV data. (iv)the limiting fragmentation phenomenon is reproduced. (iiv) we predict the total multiplicity and pseudorapidity distribution for the charged particles in Pb+Pb collisions at sNN=5.5\sqrt{s_{NN}}= 5.5 TeV. Finally, we give a qualitative analysis of the Nch/N_{ch}/ and dNch/dη/η0dN_{ch}/d\eta/|_{\eta\approx0} as function of sNN\sqrt{s_{NN}} and NpartN_{part} from RHIC to LHC.Comment: 12 pages, 8 figure

    Integration and Communication of Process Support Tools in an Online Virtual Learning Environment

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    The Education through Virtual Experience (EVE) research group based at the National University of Ireland Maynooth have successfully developed an online Virtual Learning Environment (VLE) for Astronomy as part of the Virtual Telescopes in Education (VTIE) project. The VTIE VLE has been developed to provide online software support for the engagement of schoolchildren and their teachers in a scientific process. The development of an online VLE to support a scientific process has brought about complex interactions from the user perspective. This has lead to complex integration and communication challenges from the software implementation perspective. This paper contains a high level user-centered summary of the integration and communication challenges that have arisen during the VLE development and summarizes the mechanisms used to meet these challenges

    Intermediate Wakimoto modules for Affine sl(n+1)

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    We construct certain boson type realizations of affine sl(n+1) that depend on a parameter r. When r=0 we get a Fock space realization of Imaginary Verma modules appearing in the work of the first author and when r=n they are the Wakimoto modules described in the work of Feigin and Frenkel

    Controlling Excitations Inversion of a Cooper Pair Box Interacting with a Nanomechanical Resonator

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    We investigate the action of time dependent detunings upon the excitation inversion of a Cooper pair box interacting with a nanomechanical resonator. The method employs the Jaynes-Cummings model with damping, assuming different decay rates of the Cooper pair box and various fixed and t-dependent detunings. It is shown that while the presence of damping plus constant detunings destroy the collapse/revival effects, convenient choices of time dependent detunings allow one to reconstruct such events in a perfect way. It is also shown that the mean excitation of the nanomechanical resonator is more robust against damping of the Cooper pair box for convenient values of t-dependent detunings.Comment: 11 pages, 5 figure

    Dynamic changes of small RNAs in rice spikelet development reveal specialized reproductive phasiRNA pathways

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    Dissection of the genetic pathways and mechanisms by which anther development occurs in grasses is crucial for both a basic understanding of plant development and for examining traits of agronomic importance such as male sterility. In rice, MULTIPLE SPOROCYTES1 (MSP1), a leucine-rich-repeat receptor kinase, plays an important role in anther development by limiting the number of sporocytes. OsTDL1a (a TPD1-like gene in rice) encodes a small protein that acts as a cofactor of MSP1 in the same regulatory pathway. In this study, we analyzed small RNA and mRNA changes in different stages of spikelets from wild-type rice, and from msp1 and ostdl1a mutants. Analysis of the small RNA data identified miRNAs demonstrating differential abundances. miR2275 was depleted in the two rice mutants; this miRNA is specifically enriched in anthers and functions to trigger the production of 24-nt phased secondary siRNAs (phasiRNAs) from PHAS loci. We observed that the 24-nt phasiRNAs as well as their precursor PHAS mRNAs were also depleted in the two mutants. An analysis of co-expression identified three Argonaute-encoding genes (OsAGO1d, OsAGO2b, and OsAGO18) that accumulate transcripts coordinately with phasiRNAs, suggesting a functional relationship. By mRNA in situ analysis, we demonstrated a strong correlation between the spatiotemporal pattern of these OsAGO transcripts and phasiRNA accumulations.Qili Fei, Li Yang, Wanqi Liang, Dabing Zhang, Blake C. Meyer

    SLOB, a SLOWPOKE Channel Binding Protein, Regulates Insulin Pathway Signaling and Metabolism in Drosophila

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    There is ample evidence that ion channel modulation by accessory proteins within a macromolecular complex can regulate channel activity and thereby impact neuronal excitability. However, the downstream consequences of ion channel modulation remain largely undetermined. The Drosophila melanogaster large conductance calcium-activated potassium channel SLOWPOKE (SLO) undergoes modulation via its binding partner SLO-binding protein (SLOB). Regulation of SLO by SLOB influences the voltage dependence of SLO activation and modulates synaptic transmission. SLO and SLOB are expressed especially prominently in median neurosecretory cells (mNSCs) in the pars intercerebralis (PI) region of the brain; these cells also express and secrete Drosophila insulin like peptides (dILPs). Previously, we found that flies lacking SLOB exhibit increased resistance to starvation, and we reasoned that SLOB may regulate aspects of insulin signaling and metabolism. Here we investigate the role of SLOB in metabolism and find that slob null flies exhibit changes in energy storage and insulin pathway signaling. In addition, slob null flies have decreased levels of dilp3 and increased levels of takeout, a gene known to be involved in feeding and metabolism. Targeted expression of SLOB to mNSCs rescues these alterations in gene expression, as well as the metabolic phenotypes. Analysis of fly lines mutant for both slob and slo indicate that the effect of SLOB on metabolism and gene expression is via SLO. We propose that modulation of SLO by SLOB regulates neurotransmission in mNSCs, influencing downstream insulin pathway signaling and metabolism
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