2,335 research outputs found

    Demonstration of the temporal matter-wave Talbot effect for trapped matter waves

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    We demonstrate the temporal Talbot effect for trapped matter waves using ultracold atoms in an optical lattice. We investigate the phase evolution of an array of essentially non-interacting matter waves and observe matter-wave collapse and revival in the form of a Talbot interference pattern. By using long expansion times, we image momentum space with sub-recoil resolution, allowing us to observe fractional Talbot fringes up to 10th order.Comment: 17 pages, 7 figure

    Azimuthal anisotropy at RHIC: the first and fourth harmonics

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    We report the first observations of the first harmonic (directed flow, v_1), and the fourth harmonic (v_4), in the azimuthal distribution of particles with respect to the reaction plane in Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC). Both measurements were done taking advantage of the large elliptic flow (v_2) generated at RHIC. From the correlation of v_2 with v_1 it is determined that v_2 is positive, or {\it in-plane}. The integrated v_4 is about a factor of 10 smaller than v_2. For the sixth (v_6) and eighth (v_8) harmonics upper limits on the magnitudes are reported.Comment: 6 pages with 3 figures, as accepted for Phys. Rev. Letters The data tables are at http://www.star.bnl.gov/central/publications/pubDetail.php?id=3

    Pion, kaon, proton and anti-proton transverse momentum distributions from p+p and d+Au collisions at sNN=200\sqrt{s_{NN}} = 200 GeV

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    Identified mid-rapidity particle spectra of π±\pi^{\pm}, K±K^{\pm}, and p(pˉ)p(\bar{p}) from 200 GeV p+p and d+Au collisions are reported. A time-of-flight detector based on multi-gap resistive plate chamber technology is used for particle identification. The particle-species dependence of the Cronin effect is observed to be significantly smaller than that at lower energies. The ratio of the nuclear modification factor (RdAuR_{dAu}) between protons (p+pˉ)(p+\bar{p}) and charged hadrons (hh) in the transverse momentum range 1.2<pT<3.01.2<{p_{T}}<3.0 GeV/c is measured to be 1.19±0.051.19\pm0.05(stat)±0.03\pm0.03(syst) in minimum-bias collisions and shows little centrality dependence. The yield ratio of (p+pˉ)/h(p+\bar{p})/h in minimum-bias d+Au collisions is found to be a factor of 2 lower than that in Au+Au collisions, indicating that the Cronin effect alone is not enough to account for the relative baryon enhancement observed in heavy ion collisions at RHIC.Comment: 6 pages, 4 figures, 1 table. We extended the pion spectra from transverse momentum 1.8 GeV/c to 3. GeV/

    Development, production and characterization of SARS-CoV-2 virus-like particles (Coronaviridae: <i>Orthocoronavirinae: Betacoronavirus: Sarbecovirus</i>)

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    Introduction. The COVID-19 pandemic caused by SARS-CoV-2 has created serious health problems worldwide. The most effective way to prevent the occurrence of new epidemic outbreaks is vaccination. One of the modern and effective approaches to vaccine development is the use of virus-like particles (VLPs). The aim of the study is to develop a technology for production of VLP based on recombinant SARS-CoV-2 proteins (E, M, N and S) in insect cells. Materials and methods. Synthetic genes encoding coronavirus proteins E, M, N and S were used. VLP with various surface proteins of strains similar to the Wuhan virus, Delta, Alpha and Omicron were developed and cloned into the pFastBac plasmid. The proteins were synthesized in the baculovirus expression system and assembled into VLP in the portable Trichoplusia ni cell. The presence of insertion in the baculovirus genome was determined by PCR. ELISA and immunoblotting were used to study the antigenic activity of VLP. VLP purification was performed by ultracentrifugation using 20% sucrose. Morphology was assessed using electron microscopy and dynamic light scattering. Results. VLPs consisting of recombinant SARS-CoV-2 proteins (S, M, E and N) were obtained and characterized. The specific binding of antigenic determinants in synthesized VLPs with antibodies to SARS-CoV-2 proteins has been demonstrated. The immunogenic properties of VLPs have been studied. Conclusion. The production and purification of recombinant VLPs consisting of full-length SARS-CoV-2 proteins with a universal set of surface antigens have been developed and optimized. Self-assembling particles that mimic the coronavirus virion induce a specific immune response against SARS-CoV-2

    Mid-rapidity anti-proton to proton ratio from Au+Au collisions at sNN=130 \sqrt{s_{NN}} = 130 GeV

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    We report results on the ratio of mid-rapidity anti-proton to proton yields in Au+Au collisions at \rts = 130 GeV per nucleon pair as measured by the STAR experiment at RHIC. Within the rapidity and transverse momentum range of y<0.5|y|<0.5 and 0.4 <pt<<p_t< 1.0 GeV/cc, the ratio is essentially independent of either transverse momentum or rapidity, with an average of 0.65±0.01(stat.)±0.07(syst.)0.65\pm 0.01_{\rm (stat.)} \pm 0.07_{\rm (syst.)} for minimum bias collisions. Within errors, no strong centrality dependence is observed. The results indicate that at this RHIC energy, although the pp-\pb pair production becomes important at mid-rapidity, a significant excess of baryons over anti-baryons is still present.Comment: 5 pages, 3 figures, accepted by Phys. Rev. Let

    Transverse-momentum ptp_t correlations on (η,ϕ)(\eta,\phi) from mean-ptp_{t} fluctuations in Au-Au collisions at sNN=\sqrt{s_{NN}} = 200 GeV

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    We present first measurements of the pseudorapidity and azimuth (η,ϕ)(\eta,\phi) bin-size dependence of event-wise mean transverse momentum fluctuations for Au-Au collisions at sNN=200\sqrt{s_{NN}} = 200 GeV. We invert that dependence to obtain ptp_t autocorrelations on differences (ηΔ,ϕΔ)(\eta_\Delta,\phi_\Delta) interpreted to represent velocity/temperature distributions on (η,ϕ\eta,\phi). The general form of the autocorrelations suggests that the basic correlation mechanism is parton fragmentation. The autocorrelations vary strongly with collision centrality, which suggests that fragmentation is strongly modified by a dissipative medium in the more central Au-Au collisions relative to peripheral or p-p collisions. \\Comment: 7 pages, 3 figure

    Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

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    Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

    Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

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    This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good

    Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

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    One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI
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