675 research outputs found

    Multiple (inverse) binomial sums of arbitrary weight and depth and the all-order epsilon-expansion of generalized hypergeometric functions with one half-integer value of parameter

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    We continue the study of the construction of analytical coefficients of the epsilon-expansion of hypergeometric functions and their connection with Feynman diagrams. In this paper, we show the following results: Theorem A: The multiple (inverse) binomial sums of arbitrary weight and depth (see Eq. (1.1)) are expressible in terms of Remiddi-Vermaseren functions. Theorem B: The epsilon expansion of a hypergeometric function with one half-integer value of parameter (see Eq. (1.2)) is expressible in terms of the harmonic polylogarithms of Remiddi and Vermaseren with coefficients that are ratios of polynomials. Some extra materials are available via the www at this http://theor.jinr.ru/~kalmykov/hypergeom/hyper.htmlComment: 24 pages, latex with amsmath and JHEP3.cls; v2: some typos corrected and a few references added; v3: few references added

    Scaling analysis of a divergent prefactor in the metastable lifetime of a square-lattice Ising ferromagnet at low temperatures

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    We examine a square-lattice nearest-neighbor Ising quantum ferromagnet coupled to dd-dimensional phonon baths. Using the density-matrix equation, we calculate the transition rates between configurations, which determines the specific dynamic. Applying the calculated stochastic dynamic in Monte Carlo simulations, we measure the lifetimes of the metastable state. As the magnetic field approaches ∣H∣/J=2|H|/J=2 at low temperatures, the lifetime prefactor diverges because the transition rates between certain configurations approaches zero under these conditions. Near ∣H∣/J=2|H|/J=2 and zero temperature, the divergent prefactor shows scaling behavior as a function of the field, temperature, and the dimension of the phonon baths. With proper scaling, the simulation data at different temperatures and for different dimensions of the baths collapse well onto two master curves, one for ∣H∣/J>2|H|/J>2 and one for ∣H∣/J<2|H|/J<2.Comment: published versio

    NATO Survey of Mental Health Training in Army Recruits

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    To-date, there has been no international review of mental health resilience training during Basic Training nor an assessment of what service members perceive as useful from their perspective. In response to this knowledge gap, the North Atlantic Treaty Organization (NATO) Human Factors & Medicine Research & Technology Task Group “Mental Health Training” initiated a survey and interview with seven to twenty recruits from nine nations to inform the development of such training (N = 121). All nations provided data from soldiers joining the military as volunteers, whereas two nations also provided data from conscripts. Results from the volunteer data showed relatively consistent ranking in terms of perceived demands, coping strategies, and preferences for resilience skill training across the nations. Analysis of data from conscripts identified a select number of differences compared to volunteers. Subjects also provided examples of coping with stress during Basic Training that can be used in future training; themes are presented here. Results are designed to show the kinds of demands facing new recruits and coping methods used to overcome these demands to develop relevant resilience training for NATO nations

    Quasi-particle re-summation and integral gap equation in thermal field theory

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    A new approach to quantum field theory at finite temperature and density in arbitrary space-time dimension D is developed. We focus mainly on relativistic theories, but the approach applies to non-relativistic ones as well. In this quasi-particle re-summation, the free energy takes the free-field form but with the one-particle energy ω(k⃗)\omega (\vec{k}) replaced by \vep (\vec{k}), the latter satisfying a temperature-dependent integral equation with kernel related to a zero temperature form-factor of the trace of stress-energy tensor. For 2D integrable theories the approach reduces to the thermodynamic Bethe ansatz. For relativistic theories, a thermal c-function Cqs(T)C_{\rm qs} (T) is defined for any DD based on the coefficient of the black body radiation formula. Thermodynamical constraints on it's flow are presented, showing that it can violate a ``c-theorem'' even in 2D. At a fixed point CqsC_{\rm qs} is a function of thermal gap parameters which generalizes Roger's dilogarithm to higher dimensions. This points to a strategy for classifying rational theories based on ``polylogarithmic ladders'' in mathematics, and many examples are worked out. An argument suggests that the 3D Ising model has Cqs=7/8C_{\rm qs} = 7/8. (In 3D a free fermion has Cqs=3/4C_{\rm qs} = 3/4.) Other applications are discussed, including the free energy of anyons in 2D and 3D, phase transitions with a chemical potential, and the equation of state for cosmological dark energy.Comment: Version 4: Published versio

    Divergent pathogenetic outcomes in BALB/c mice following Omicron subvariant infection

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    Following the emergence of B.1.1.529 Omicron, the SARS-CoV-2 virus evolved into a significant number of sublineage variants that possessed numerous mutations throughout the genome, but particularly within the spike glycoprotein (S) gene. For example, the BQ.1.1 and the XBB.1 and XBB.1.5 subvariants contained 34 and 41 mutations in S, respectively. However, these variants elicited largely replication only or mild disease phenotypes in mice. To better model pathogenic outcomes and measure countermeasure performance, we developed mouse adapted versions (BQ.1.1 MA; XBB.1 MA; XBB.1.5 MA) that reflect more pathogenic acute phase pulmonary disease symptoms of SARS-CoV-2, as well as derivative strains expressing nano-luciferase (nLuc) in place of ORF7 (BQ.1.1 nLuc; XBB.1 nLuc; XBB.1.5 nLuc). Amongst the mouse adapted (MA) viruses, a wide range of disease outcomes were observed including mortality, weight loss, lung dysfunction, and tissue viral loads in the lung and nasal turbinates. Intriguingly, XBB.1 MA and XBB.1.5 MA strains, which contained identical mutations throughout except at position F486S/P in S, exhibited divergent disease outcomes in mice (Ao et al., 2023). XBB.1.5 MA infection was associated with significant weight loss and ∌45 % mortality across two independent studies, while XBB.1 MA infected animals suffered from mild weight loss and only 10 % mortality across the same two independent studies. Additionally, the development and use of nanoluciferase expressing strains provided moderate throughput for live virus neutralization assays. The availability of small animal models for the assessment of Omicron VOC disease potential will enable refined capacity to evaluate the efficacy of on market and pre-clinical therapeutics and interventions

    High-Density Amplicon Sequencing Identifies Community Spread and Ongoing Evolution of SARS-CoV-2 in the Southern United States

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    Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is constantly evolving. Prior studies focused on high-case-density locations, such as the northern and western metropolitan areas of the United States. This study demonstrates continued SARS-CoV-2 evolution in a suburban southern region of the United States by high-density amplicon sequencing of symptomatic cases. 57% of strains carry the spike D614G variant, which is associated with higher genome copy numbers, and its prevalence expands with time. Four strains carry a deletion in a predicted stem loop of the 3â€Č UTR. The data are consistent with community spread within local populations and the larger continental United States. The data instill confidence in current testing sensitivity and validate “testing by sequencing” as an option to uncover cases, particularly nonstandard coronavirus disease 2019 (COVID-19) clinical presentations. This study contributes to the understanding of COVID-19 through an extensive set of genomes from a non-urban setting and informs vaccine design by defining D614G as a dominant and emergent SARS-CoV-2 isolate in the United States

    SCExAO/MEC and CHARIS Discovery of a Low Mass, 6 AU-Separation Companion to HIP 109427 using Stochastic Speckle Discrimination and High-Contrast Spectroscopy

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    We report the direct imaging discovery of a low-mass companion to the nearby accelerating A star, HIP 109427, with the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument coupled with the MKID Exoplanet Camera (MEC) and CHARIS integral field spectrograph. CHARIS data reduced with reference star PSF subtraction yield 1.1-2.4 ÎŒ\mum spectra. MEC reveals the companion in YY and JJ band at a comparable signal-to-noise ratio using stochastic speckle discrimination, with no PSF subtraction techniques. Combined with complementary follow-up LpL_{\rm p} photometry from Keck/NIRC2, the SCExAO data favors a spectral type, effective temperature, and luminosity of M4-M5.5, 3000-3200 KK, and log⁥10(L/L⊙)=−2.28−0.04+0.04\log_{10}(L/L_{\rm \odot}) = -2.28^{+0.04}_{-0.04}, respectively. Relative astrometry of HIP 109427 B from SCExAO/CHARIS and Keck/NIRC2, and complementary Gaia-Hipparcos absolute astrometry of the primary favor a semimajor axis of 6.55−0.48+3.06.55^{+3.0}_{-0.48} au, an eccentricity of 0.54−0.15+0.280.54^{+0.28}_{-0.15}, an inclination of 66.7−14+8.566.7^{+8.5}_{-14} degrees, and a dynamical mass of 0.280−0.059+0.180.280^{+0.18}_{-0.059} M⊙M_{\odot}. This work shows the potential for extreme AO systems to utilize speckle statistics in addition to widely-used post-processing methods to directly image faint companions to nearby stars near the telescope diffraction limit.Comment: 13 pages, 7 figures, 3 table

    Study of CP violation in Dalitz-plot analyses of B0 --> K+K-KS, B+ --> K+K-K+, and B+ --> KSKSK+

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    We perform amplitude analyses of the decays B0→K+K−KS0B^0 \to K^+K^-K^0_S, B+→K+K−K+B^+ \rightarrow K^+K^-K^+, and B+→KS0KS0K+B^+ \to K^0_S K^0_S K^+, and measure CP-violating parameters and partial branching fractions. The results are based on a data sample of approximately 470×106470\times 10^6 BBˉB\bar{B} decays, collected with the BABAR detector at the PEP-II asymmetric-energy BB factory at the SLAC National Accelerator Laboratory. For B+→K+K−K+B^+ \to K^+K^-K^+, we find a direct CP asymmetry in B+→ϕ(1020)K+B^+ \to \phi(1020)K^+ of ACP=(12.8±4.4±1.3)A_{CP}= (12.8\pm 4.4 \pm 1.3)%, which differs from zero by 2.8σ2.8 \sigma. For B0→K+K−KS0B^0 \to K^+K^-K^0_S, we measure the CP-violating phase ÎČeff(ϕ(1020)KS0)=(21±6±2)∘\beta_{\rm eff} (\phi(1020)K^0_S) = (21\pm 6 \pm 2)^\circ. For B+→KS0KS0K+B^+ \to K^0_S K^0_S K^+, we measure an overall direct CP asymmetry of ACP=(4−5+4±2)A_{CP} = (4 ^{+4}_{-5} \pm 2)%. We also perform an angular-moment analysis of the three channels, and determine that the fX(1500)f_X(1500) state can be described well by the sum of the resonances f0(1500)f_0(1500), f2â€Č(1525)f_2^{\prime}(1525), and f0(1710)f_0(1710).Comment: 35 pages, 68 postscript figures. v3 - minor modifications to agree with published versio
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