3,581 research outputs found

    On a generalization of Jacobi's elliptic functions and the Double Sine-Gordon kink chain

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    A generalization of Jacobi's elliptic functions is introduced as inversions of hyperelliptic integrals. We discuss the special properties of these functions, present addition theorems and give a list of indefinite integrals. As a physical application we show that periodic kink solutions (kink chains) of the double sine-Gordon model can be described in a canonical form in terms of generalized Jacobi functions.Comment: 18 pages, 9 figures, 3 table

    Glueball and gluelump spectrum in abelian projected QCD

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    We study glueball and gluelump spectra calculated after abelian projection in both quenched and Nf=2N_f=2 full QCD. The abelian projection is made after MA gauge fixing. We demonstrate that both spectra can be recovered despite the problem with positivity. We suggest the interpretation of some of the gluelump states in the language of the abelian projected theory.Comment: Lattice 2001(confinement), 3 page

    Binary black hole late inspiral: Simulations for gravitational wave observations

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    Coalescing binary black hole mergers are expected to be the strongest gravitational wave sources for ground-based interferometers, such as the LIGO, VIRGO, and GEO600, as well as the space-based interferometer LISA. Until recently it has been impossible to reliably derive the predictions of General Relativity for the final merger stage, which takes place in the strong-field regime. Recent progress in numerical relativity simulations is, however, revolutionizing our understanding of these systems. We examine here the specific case of merging equal-mass Schwarzschild black holes in detail, presenting new simulations in which the black holes start in the late inspiral stage on orbits with very low eccentricity and evolve for ~1200M through ~7 orbits before merging. We study the accuracy and consistency of our simulations and the resulting gravitational waveforms, which encompass ~14 cycles before merger, and highlight the importance of using frequency (rather than time) to set the physical reference when comparing models. Matching our results to PN calculations for the earlier parts of the inspiral provides a combined waveform with less than half a cycle of accumulated phase error through the entire coalescence. Using this waveform, we calculate signal-to-noise ratios (SNRs) for iLIGO, adLIGO, and LISA, highlighting the contributions from the late-inspiral and merger-ringdown parts of the waveform which can now be simulated numerically. Contour plots of SNR as a function of z and M show that adLIGO can achieve SNR >~ 10 for some intermediate-mass binary black holes (IMBBHs) out to z ~ 1, and that LISA can see massive binary black holes (MBBHs) in the range 3x10^4 100 out to the earliest epochs of structure formation at z > 15.Comment: 17 pages, 20 figures. Final published versio

    Two-gap superconductivity with line nodes in CsCa2_2Fe4_4As4_4F2_2

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    We report the results of a muon-spin rotation (μ\muSR) experiment to determine the superconducting ground state of the iron-based superconductor CsCa2_2Fe4_4As4_4F2_2 with Tc28.3T_{\rm c} \approx 28.3\,K. This compound is related to the fully-gapped superconductor CaCsFe4_4As4_4, but here the Ca-containing spacer layer is replaced with one containing Ca2_2F2_2. The temperature evolution of the penetration depth strongly suggests the presence of line nodes and is best modelled by a system consisting of both an ss- and a dd-wave gap. We also find a potentially magnetic phase which appears below 10\approx 10\,K but does not appear to compete with the superconductivity. This compound contains the largest alkali atom in this family of superconductors and our results yield a value for the in-plane penetration depth of λab(T=0)=423(5)\lambda_{ab}(T=0)=423(5)\,nm.Comment: 6 pages, 2 figure

    On the Corner Elements of the CKM and PMNS Matrices

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    Recent experiments show that the top-right corner element (Ue3U_{e3}) of the PMNS, like that (VubV_{ub}) of the CKM, matrix is small but nonzero, and suggest further via unitarity that it is smaller than the bottom-left corner element (Uτ1U_{\tau 1}), again as in the CKM case (Vub<VtdV_{ub} < V_{td}). An attempt in explaining these facts would seem an excellent test for any model of the mixing phenomenon. Here, it is shown that if to the assumption of a universal rank-one mass matrix, long favoured by phenomenologists, one adds that this matrix rotates with scale, then it follows that (A) by inputting the mass ratios mc/mt,ms/mb,mμ/mτm_c/m_t, m_s/m_b, m_\mu/m_\tau, and m2/m3m_2/m_3, (i) the corner elements are small but nonzero, (ii) Vub<VtdV_{ub} < V_{td}, Ue3<Uτ1U_{e 3} < U_{\tau 1}, (iii) estimates result for the ratios Vub/VtdV_{ub}/V_{td} and Ue3/Uτ1U_{e 3}/U_{\tau 1}, and (B) by inputting further the experimental values of Vus,VtbV_{us}, V_{tb} and Ue2,Uμ3U_{e2},U_{\mu 3}, (iv) estimates result for the values of the corner elements themselves. All the inequalities and estimates obtained are consistent with present data to within expectation for the approximations made.Comment: 9 pages, 2 figures, updated with new experimental data and more detail

    Combined analysis of microbial metagenomic and metatranscriptomic sequencing data to assess in situ physiological conditions in the premature infant gut.

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    Microbes alter their transcriptomic profiles in response to the environment. The physiological conditions experienced by a microbial community can thus be inferred using meta-transcriptomic sequencing by comparing transcription levels of specifically chosen genes. However, this analysis requires accurate reference genomes to identify the specific genes from which RNA reads originate. In addition, such an analysis should avoid biases in transcript counts related to differences in organism abundance. In this study we describe an approach to address these difficulties. Sample-specific meta-genomic assembled genomes (MAGs) were used as reference genomes to accurately identify the origin of RNA reads, and transcript ratios of genes with opposite transcription responses were compared to eliminate biases related to differences in organismal abundance, an approach hereafter named the "diametric ratio" method. We used this approach to probe the environmental conditions experienced by Escherichia spp. in the gut of 4 premature infants, 2 of whom developed necrotizing enterocolitis (NEC), a severe inflammatory intestinal disease. We analyzed twenty fecal samples taken from four premature infants (4-6 time points from each infant), and found significantly higher diametric ratios of genes associated with low oxygen levels in samples of infants later diagnosed with NEC than in samples without NEC. We also show this method can be used for examining other physiological conditions, such as exposure to nitric oxide and osmotic pressure. These study results should be treated with caution, due to the presence of confounding factors that might also distinguish between NEC and control infants. Nevertheless, together with benchmarking analyses, we show here that the diametric ratio approach can be applied for evaluating the physiological conditions experienced by microbes in situ. Results from similar studies can be further applied for designing diagnostic methods to detect NEC in its early developmental stages

    A Comprehensive Mechanism Reproducing the Mass and Mixing Parameters of Quarks and Leptons

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    It is shown that if, from the starting point of a universal rank-one mass matrix long favoured by phenomenologists, one adds the assumption that it rotates (changes its orientation in generation space) with changing scale, one can reproduce, in terms of only 6 real parameters, all the 16 mass ratios and mixing parameters of quarks and leptons. Of these 16 quantities so reproduced, 10 for which data exist for direct comparison (i.e. the CKM elements including the CP-violating phase, the angles θ12,θ13,θ23\theta_{12}, \theta_{13}, \theta_{23} in ν\nu-oscillation, and the masses mc,mμ,mem_c, m_\mu, m_e) agree well with experiment, mostly to within experimental errors; 4 others (ms,mu,md,mν2m_s, m_u, m_d, m_{\nu_2}), the experimental values for which can only be inferred, agree reasonably well; while 2 others (mν1,δCPm_{\nu_1}, \delta_{CP} for leptons), not yet measured experimentally, remain as predictions. In addition, one gets as bonuses, estimates for (i) the right-handed neutrino mass mνRm_{\nu_R} and (ii) the strong CP angle θ\theta inherent in QCD. One notes in particular that the output value for sin22θ13\sin^2 2 \theta_{13} from the fit agrees very well with recent experiments. By inputting the current experimental value with its error, one obtains further from the fit 2 new testable constraints: (i) that θ23\theta_{23} must depart from its "maximal" value: sin22θ230.935±0.021\sin^2 2 \theta_{23} \sim 0.935 \pm 0.021, (ii) that the CP-violating (Dirac) phase in the PMNS would be smaller than in the CKM matrix: of order only sinδCP0.31|\sin \delta_{CP}| \leq 0.31 if not vanishing altogether.Comment: 37 pages, 1 figur

    Breaking the Rules: Low Trait or State Self-Control Increases Social Norm Violations

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    Two pilot and six studies indicated that poor self-control causes people to violate social norms and rules that are effortful to follow. Lower trait self-control was associated with a greater willingness to take ethical risks and use curse words. Participants who completed an initial self-control task that reduced the capacity for self-control used more curse words and were more willing to take ethical risks than participants who completed a neutral task. Poor self-control was also associated with violating explicit rules given by the experimenter. Depleting self-control resources in a self-control exercise caused participants subsequently to talk when they had been instructed to remain silent. Low trait self-control and poor performance on a behavioral measure of self-control (the Stroop task) predicted poor compliance following experimental instructions over a 2-week span. Poor self-control thus undermines adherence to some social rules and regulations, therefore possibly contributing to a broad variety of social ills
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