1,748 research outputs found

    Tensor coupling effects on spin symmetry in anti-Lambda spectrum of hypernuclei

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    The effects of ΛˉΛˉω\bar\Lambda\bar\Lambda\omega-tensor coupling on the spin symmetry of Λˉ\bar{\Lambda} spectra in Λˉ\bar{\Lambda}-nucleus systems have been studied with the relativistic mean-field theory. Taking 12^{12}C+Λˉ\bar{\Lambda} as an example, it is found that the tensor coupling enlarges the spin-orbit splittings of Λˉ\bar\Lambda by an order of magnitude although its effects on the wave functions of Λˉ\bar{\Lambda} are negligible. Similar conclusions has been observed in Λˉ\bar{\Lambda}-nucleus of different mass regions, including 16^{16}O+Λˉ\bar{\Lambda}, 40^{40}Ca+Λˉ\bar{\Lambda} and 208^{208}Pb+Λˉ\bar{\Lambda}. It indicates that the spin symmetry in anti-lambda-nucleus systems is still good irrespective of the tensor coupling.Comment: 12 pages, 3 figures

    Cosmic positron and antiproton constraints on the gauge-Higgs Dark Matter

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    We calculate the cosmic ray positron and antiproton spectra of a gauge-Higgs dark matter candidate in a warped five-dimensional SO(5)×U(1)SO(5) \times U(1) gauge-Higgs unification model. The stability of the gauge-Higgs boson is guaranteed by the H parity under which only the Higgs boson is odd at low energy. The 4-point vertices of HHW^+W^- and HHZZ, allowed by H parity conservation, have the same magnitude as in the standard model, which yields efficient annihilation rate for mH>mWm_H > m_W. The most dominant annihilation channel is HH→W+W−H H \to W^+ W^- followed by the subsequent decays of the WW bosons into positrons or quarks, which undergo fragmentation into antiproton. Comparing with the observed positron and antiproton spectra with the PAMALA and Fermi/LAT, we found that the Higgs boson mass cannot be larger than 90 GeV, in order not to overrun the observations. Together with the constraint on not overclosing the Universe, the valid range of the dark matter mass is restricted to 70-90 GeV.Comment: 13 pages, 3 figure

    Interventions for post-stroke fatigue

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    BACKGROUND: Post-stroke fatigue (PSF) is a common and distressing problem after stroke. The best ways to prevent or treat PSF are uncertain. Several different interventions can be argued to have a rational basis. OBJECTIVES: To determine whether, among people with stroke, any intervention reduces the proportion of people with fatigue, fatigue severity, or both; and to determine the effect of intervention on health-related quality of life, disability, dependency and death, and whether such intervention is cost effective. SEARCH METHODS: We searched the Cochrane Stroke Group Trials Register (last searched May 2014), Cochrane Central Register of Controlled Trials (The Cochrane Library, 2014, Issue 4), MEDLINE (1950 to May 2014), EMBASE (1980 to May 2014), CINAHL (1982 to May 2014), AMED (1985 to May 2014), PsycINFO (1967 to May 2014), Digital Dissertations (1861 to May 2014), British Nursing Index (1985 to May 2014), PEDro (searched May 2014) and PsycBITE (searched May 2014). We also searched four ongoing trials registries, scanned reference lists, performed citation tracking of included trials and contacted experts. SELECTION CRITERIA: Two review authors independently scrutinised all titles and abstracts and excluded obviously irrelevant studies. We obtained the full texts for potentially relevant studies and three review authors independently applied the inclusion criteria. We included randomised controlled trials (RCTs) that compared an intervention with a control, or compared different interventions for PSF. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data and assessed risk of bias for each included trial. The primary outcomes were severity of fatigue, or proportion of people with fatigue after treatment. We performed separate analyses for trials investigating efficacy in treating PSF, trials investigating efficacy in preventing PSF and trials not primarily investigating efficacy in PSF but which reported fatigue as an outcome. We pooled results from trials that had a control arm. For trials that compared different potentially active interventions without a control arm, we performed analyses for individual trials without pooling.We calculated standardised mean difference (SMD) as the effect size for continuous outcomes and risk ratio (RR) for dichotomous outcomes. We pooled the results using a random-effects model and assessed heterogeneity using the I(2) statistic. We performed separate subgroup analyses for pharmacological and non-pharmacological interventions. We also performed sensitivity analyses to assess the influence of methodological quality. MAIN RESULTS: We retrieved 12,490 citations, obtained full texts for 58 studies and included 12 trials (three from the 2008 search and nine from the 2014 search) with 703 participants. Eight trials primarily investigated the efficacy in treating PSF, of which six trials with seven comparisons provided data suitable for meta-analysis (five pharmacological interventions: fluoxetine, enerion, (-)-OSU6162, citicoline and a combination of Chinese herbs; and two non-pharmacological interventions: a fatigue education programme and a mindfulness-based stress reduction programme). The fatigue severity was lower in the intervention groups than in the control groups (244 participants, pooled SMD -1.07, 95% confidence interval (CI) -1.93 to -0.21), with significant heterogeneity between trials (I(2) = 87%, degrees of freedom (df) = 6, P value < 0.00001). The beneficial effect was not seen in trials that had used adequate allocation concealment (two trials, 89 participants, SMD -0.38, 95% CI -0.80 to 0.04) or trials that had used adequate blinding of outcome assessors (four trials, 198 participants, SMD -1.10, 95% CI -2.31 to 0.11).No trial primarily investigated the efficacy in preventing PSF.Four trials (248 participants) did not primarily investigate the efficacy on fatigue but other symptoms after stroke. None of these interventions showed any benefit on reducing PSF, which included tirilazad mesylate, continuous positive airway pressure for sleep apnoea, antidepressants and a self management programme for recovery from chronic diseases. AUTHORS' CONCLUSIONS: There was insufficient evidence on the efficacy of any intervention to treat or prevent fatigue after stroke. Trials to date have been small and heterogeneous, and some have had a high risk of bias. Some of the interventions described were feasible in people with stroke, but their efficacy should be investigated in RCTs with a more robust study design and adequate sample sizes

    Scaling of Anisotropic Flows and Nuclear Equation of State in Intermediate Energy Heavy Ion Collisions

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    Elliptic flow (v2v_2) and hexadecupole flow (v4v_4) of light clusters have been studied in details for 25 MeV/nucleon 86^{86}Kr + 124^{124}Sn at large impact parameters by Quantum Molecular Dynamics model with different potential parameters. Four parameter sets which include soft or hard equation of state (EOS) with/without symmetry energy term are used. Both number-of-nucleon (AA) scaling of the elliptic flow versus transverse momentum (ptp_t) and the scaling of v4/A2v_4/A^{2} versus (pt/A)2(p_t/A)^2 have been demonstrated for the light clusters in all above calculation conditions. It was also found that the ratio of v4/v22v_4/{v_2}^2 keeps a constant of 1/2 which is independent of ptp_t for all the light fragments. By comparisons among different combinations of EOS and symmetry potential term, the results show that the above scaling behaviors are solid which do not depend the details of potential, while the strength of flows is sensitive to EOS and symmetry potential term.Comment: 5 pages, 5 figure

    Multiparty Quantum Secret Report

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    A multiparty quantum secret report scheme is proposed with quantum encryption. The boss Alice and her MM agents first share a sequence of (MM+1)-particle Greenberger--Horne--Zeilinger (GHZ) states that only Alice knows which state each (MM+1)-particle quantum system is in. Each agent exploits a controlled-not (CNot) gate to encrypt the travelling particle by using the particle in the GHZ state as the control qubit. The boss Alice decrypts the travelling particle with a CNot gate after performing a σx\sigma_x operation on her particle in the GHZ state or not. After the GHZ states (the quantum key) are used up, the parties check whether there is a vicious eavesdropper, say Eve, monitoring the quantum line, by picking out some samples from the GHZ states shared and measure them with two measuring bases. After confirming the security of the quantum key, they use the GHZ states remained repeatedly for next round of quantum communication. This scheme has the advantage of high intrinsic efficiency for qubits and the total efficiency.Comment: 4 pages, no figure

    Dirac quasinormal modes of a Schwarzschild black hole surrounded by free static spherically symmetric quintessence

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    We evaluate the quasinormal modes of massless Dirac perturbation in a Schwarzschild black hole surrounded by the free static spherically symmetric quintessence by using the third-order WKB approximation. The result shows that due to the presence of quintessence, the massless field damps more slowly. The real part of the quasinormal modes increases and the the absolute value of the imaginary part increases when the state parameter wqw_q increases. In other words, the massless Dirac field decays more rapidly for the larger wqw_q. And the peak value of potential barrier gets higher as ∣k∣|k| increases and the location of peak moves along the right for fixed wqw_q.Comment: 7 pages, 4 figure

    Unified theory for Goos-H\"{a}nchen and Imbert-Fedorov effects

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    A unified theory is advanced to describe both the lateral Goos-H\"{a}nchen (GH) effect and the transverse Imbert-Fedorov (IF) effect, through representing the vector angular spectrum of a 3-dimensional light beam in terms of a 2-form angular spectrum consisting of its 2 orthogonal polarized components. From this theory, the quantization characteristics of the GH and IF displacements are obtained, and the Artmann formula for the GH displacement is derived. It is found that the eigenstates of the GH displacement are the 2 orthogonal linear polarizations in this 2-form representation, and the eigenstates of the IF displacement are the 2 orthogonal circular polarizations. The theoretical predictions are found to be in agreement with recent experimental results.Comment: 15 pages, 3 figure

    Coupled KdV equations derived from atmospherical dynamics

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    Some types of coupled Korteweg de-Vries (KdV) equations are derived from an atmospheric dynamical system. In the derivation procedure, an unreasonable yy-average trick (which is usually adopted in literature) is removed. The derived models are classified via Painlev\'e test. Three types of Ï„\tau-function solutions and multiple soliton solutions of the models are explicitly given by means of the exact solutions of the usual KdV equation. It is also interesting that for a non-Painlev\'e integrable coupled KdV system there may be multiple soliton solutions.Comment: 19 pages, 2 figure

    MedEval: A Multi-Level, Multi-Task, and Multi-Domain Medical Benchmark for Language Model Evaluation

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    Curated datasets for healthcare are often limited due to the need of human annotations from experts. In this paper, we present MedEval, a multi-level, multi-task, and multi-domain medical benchmark to facilitate the development of language models for healthcare. MedEval is comprehensive and consists of data from several healthcare systems and spans 35 human body regions from 8 examination modalities. With 22,779 collected sentences and 21,228 reports, we provide expert annotations at multiple levels, offering a granular potential usage of the data and supporting a wide range of tasks. Moreover, we systematically evaluated 10 generic and domain-specific language models under zero-shot and finetuning settings, from domain-adapted baselines in healthcare to general-purposed state-of-the-art large language models (e.g., ChatGPT). Our evaluations reveal varying effectiveness of the two categories of language models across different tasks, from which we notice the importance of instruction tuning for few-shot usage of large language models. Our investigation paves the way toward benchmarking language models for healthcare and provides valuable insights into the strengths and limitations of adopting large language models in medical domains, informing their practical applications and future advancements.Comment: Accepted to EMNLP 2023. Camera-ready version: updated IRB, added more evaluation results on LLMs such as GPT4, LLaMa2, and LLaMa2-cha
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