We have theoretically investigated transport properties of the classical Heisenberg antiferromagnet on the triangular lattice, in which a binding-unbinding topological transition of Z2 vortices is ...predicted to occur at a finite temperature Tv. It is shown by means of the hybrid Monte Carlo and spin-dynamics simulations that the longitudinal spin-current conductivity exhibits a divergence at Tv, while the thermal conductivity only shows a monotonic temperature dependence with no clear anomaly at Tv. The significant enhancement of the spin-current conductivity is found to be due to the rapid growth of the spin-current-relaxation time toward Tv, which can be understood as a manifestation of the topological nature of the free Z2 vortex whose lifetime gets longer toward Tv. The result suggests that the spin-current measurement is a promising probe to detect the Z2-vortex topological transition, which has remained elusive in experiments.
We have theoretically investigated transport properties of the classical Heisenberg antiferromagnet on the triangular lattice, in which a binding-unbinding topological transition of Z_{2} vortices is ...predicted to occur at a finite temperature T_{v}. It is shown by means of the hybrid Monte Carlo and spin-dynamics simulations that the longitudinal spin-current conductivity exhibits a divergence at T_{v}, while the thermal conductivity only shows a monotonic temperature dependence with no clear anomaly at T_{v}. The significant enhancement of the spin-current conductivity is found to be due to the rapid growth of the spin-current-relaxation time toward T_{v}, which can be understood as a manifestation of the topological nature of the free Z_{2} vortex whose lifetime gets longer toward T_{v}. The result suggests that the spin-current measurement is a promising probe to detect the Z_{2}-vortex topological transition, which has remained elusive in experiments.
We investigated the possibility of determining the internal structure of exotic hadrons by using high-energy reaction processes, where quarks and gluons are appropriate degrees of freedom. In ...particular, it should be valuable to investigate the high-energy exclusive processes that include generalized parton distributions (GPDs) and generalized distribution amplitudes (GDAs). The GPDs and GDAs contain momentum distributions of partons and form factors. We found that the exotic nature appears in momentum distributions of quarks as suggested by the constituent-counting rule and in the form factors associated with exotic hadron sizes and the number of constituents. We also propose that these exotic signatures should be found in the exclusive production processes of exotic hadrons from gamma * gamma in electron-positron annihilation. For example, the GDAs contain information on a timelike form factor of the energy-momentum tensor of a hadron h. We show that the cross section of e gamma arrow right e + hh is sensitive to the exotic signature by looking at the hh invariant-mass dependence by taking light hadrons, h = functionof sub(0)(980) and a sub(0)(980). From such GDA measurements, the tomography of exotic hadrons becomes possible, for example, with Belle and BABAR experiments and a future linear collider.
We propose to use hard exclusive production of an exotic hadron for finding its internal quark-gluon configuration by the constituent-counting rule in perturbative QCD. In particular, the cross ...section for the exclusive process pi super(-) + p arrow right K super(0) + Lambda(1405) is estimated at the scattering angle straighttheta = 90degrees in the center-of-mass frame by using current experimental data. In comparison, the cross section for the ground-state Lambda production pi super(-) + p arrow right K super(0) + Lambda is also shown. We suggest that the internal quark configuration of Lambda(1405) should be determined by the asymptotic scaling behavior of the cross section. If it is an ordinary three-quark baryon, the scaling of the cross section is s super(8)dsigma/dt = constant, whereas it is s super(10)dsigma/dt = constant if Lambda(1405) is a five-quark hadron, where s and t are Mandelstam variables. Such a measurement will be possible, for example, by using the high-momentum beam line at Japan Proton Accelerator Research Complex. In addition, another exclusive process gamma +p arrow right K super(+) + Lambda(1405) could be investigated at laser electron photon beam line at SPring-8 and JLab for finding the nature of Lambda(1405). We indicate that the constituent-counting rule could be used as a valuable quantity in determining internal structure of exotic hadrons by high-energy exclusive processes, where quark-gluon degrees of freedom explicitly appear. Furthermore, it is interesting to investigate the transition from hadron degrees of freedom to quark-gluon ones for exclusive exotic-hadron production processes.
The contribution of quarks with masses m≫ΛQCD is the only part of the structure functions in deep-inelastic scattering (DIS) which is not yet known at the next-to-next-to-leading order (NNLO) of ...perturbative QCD. We present improved partial NNLO results for the most important structure function F2(x,Q2) near the partonic threshold, in the high-energy (small-x) limit and at high scales Q2≫m2; and employ these results to construct approximations for the gluon and quark coefficient functions which cover the full kinematic plane. The approximation uncertainties are carefully investigated, and found to be large only at very small values, x≲10−3, of the Bjorken variable.
Meticillin-resistant Staphylococcus aureus (MRSA) is the most common pathogen in orthopaedic surgical site infections (SSIs). However, few studies have investigated the transmission process of ...orthopaedic MRSA SSI.
To investigate the transmission process of orthopaedic MRSA SSI using epidemiological and molecular analyses and to determine a method to prevent MRSA SSI in nosocomial orthopaedic surgery.
Active MRSA surveillance, preoperative decolonization and contact precautions for MRSA-positive cases was performed at our institution. Changes in epidemic strains were evaluated and the possibility of transmission from patients in an orthopaedic ward of a Japanese tertiary-care hospital was assessed by genotyping stored MRSA strains. In addition, data on the prevalence of MRSA SSI, MRSA colonization, and use of an alcohol antiseptic agent (mL/patient-days) during 2005–2022 were retrospectively assessed.
SCCmec type II strain in the SSI group decreased over time, associated with fewer outbreaks. Even during a period of high infection rates, no cases of transmission-induced SSI from nasal MRSA carriers were identified. The infection rate correlated negatively with the use of an alcohol antiseptic agent (r = −0.82; P < 0.0001). Two cases among five nasal carriers developed MRSA SSI caused by strains different from those related to nasal colonization.
The infection control measures for transmission from the hospital reservoirs including strict adherence to hand hygiene and decolonization of carriers is likely to be important for the prevention of orthopaedic MRSA SSI. However, the need for contact precautions for decolonized nasal carriers might be low.
We present observations of the Trumpler 14/Carina I region carried out using the Stratospheric Terahertz Observatory 2. The Trumpler 14/Carina I region is in the western part of the Carina Nebula ...Complex (CNC), which is one of the most extreme star-forming regions in the Milky Way. We observed Trumpler 14/Carina I in the 158 m transition of C ii with a spatial resolution of 48″ and a velocity resolution of 0.17 km s−1. The observations cover a 0 25 by 0 28 area with central position l = 297 34, b = −0 60. The kinematics show that bright C ii structures are spatially and spectrally correlated with the surfaces of CO clouds, tracing the photodissociation region (PDR) and ionization front of each molecular cloud. Along seven lines of sight (LOSs) that traverse Tr 14 into the dark ridge to the southwest, we find that the C ii luminosity from the H ii region is 3.7 times that from the PDR. In the same LOS, we find in the PDRs an average ratio of 1 : 4.1 : 5.6 for the mass in atomic gas : dark CO gas : molecular gas traced by CO. Comparing multiple gas tracers, including H i 21 cm, C ii, CO, and radio recombination lines, we find that the H ii regions of the CNC are well described as H ii regions with one side freely expanding toward us, consistent with the Champagne model of ionized gas evolution. The dispersal of the GMC in this region is dominated by EUV photoevaporation; the dispersal timescale is 20-30 Myr.
Surgical antimicrobial prophylaxis (SAP) is one of the major purposes of antimicrobial use.
To determine the adherence to the Japanese SAP guidelines in Japanese university hospitals.
This was a ...retrospective cohort study including 15 general hospitals and one dental university hospital. Up to three cases of 18 designated surgeries were evaluated regarding adherence to Japanese SAP guidelines: selection of antibiotics, timing of administration, re-dosing intervals, and duration of SAP. When all items were appropriate, surgery was defined as ‘appropriate’.
In total, 688 cases (22–45 cases per surgery) were included. The overall appropriateness was 46.8% (322/688), and the appropriateness of each surgery ranged from 8.0% (2/25, cardiac implantable electronic device implantation) to 92.1% (35/38, distal gastrectomy). The appropriateness of each item was as follows: pre/intraoperative selections, 78.5% (540/688); timing of administrations, 96.0% (630/656); re-dosing intervals, 91.6% (601/656); postoperative selection, 78.9% (543/688); and duration of SAP, 61.4% (423/688). The overall appropriateness of hospitals ranged from 17.6% (9/51) to 73.3% (33/45). The common reasons for inappropriateness were the longer duration (38.5%, 265/688) and choice of antibiotics with a non-optimal antimicrobial spectrum before/during, and after surgery (19.0%, 131/688 and 16.9%, 116/688, respectively), compared to the guideline.
Adherence to the guidelines differed greatly between the surgeries and hospitals. Large-scale multi-centre surveillance of SAP in Japanese hospitals is necessary to identify inappropriate surgeries, factors related to the appropriateness, and incidences of surgical site infections.
Ions with similar charge-to-mass ratios cannot be separated from existing beam profile monitors (BPMs) in nuclear facilities in which low-energy radioactive ions are produced due to nuclear fusion ...reactions. In this study, we developed a BPM using a microchannel plate and a charge-coupled device to differentiate the beam profiles of alpha-decaying radioactive isotopes from other ions (reaction products) produced in a nuclear reaction. This BPM was employed to optimize the low-energy radioactive francium ion (Fr+) beam developed at the Cyclotron and Radioisotope Center (CYRIC), Tohoku University, for electron permanent electric dipole moment (e-EDM) search experiments using Fr atoms. We demonstrated the performance of the BPM by separating the Fr+ beam from other reaction products produced during the nuclear fusion reaction of an oxygen (18O) beam and gold (197Au) target. However, as the mass of Au is close to that of Fr, separating the ions of these elements using a mass filter is a challenge, and a dominant number of Au+ renders the Fr+ beam profile invisible when using a typical BPM. Therefore, by employing the new BPM, we could successfully observe the Fr+ beam and other ion beams distinctly by measuring the alpha decay of Fr isotopes. This novel technique to monitor the alpha-emitting radioactive beam covers a broad range of lifetimes, for example, from approximately 1 s to 10 min, and can be implemented for other alpha-emitter beams utilized for medical applications.
Abstract
Fragmentation functions are determined for the pion and kaon by global analyses of charged-hadron production data in electron–positron annihilation. Accurate measurements were reported by ...the Belle and BaBar collaborations for the fragmentation functions at the center-of-mass energies of 10.52 and 10.54 GeV, respectively, at the KEK and SLAC B factories, whereas other available e+e− measurements were mostly done at higher energies, mainly at the Z mass of 91.2 GeV. There is a possibility that gluon fragmentation functions, as well as quark fragmentation functions, are accurately determined by scaling violation. We report our global analysis of the fragmentation functions especially to show impacts of the B-factory measurements on the fragmentation function determination. Our results indicate that the fragmentation functions are determined more accurately not only by the scaling violation but also by the high-statistical nature of the Belle and BaBar data. However, there are some tensions between the Belle and BaBar data in comparison with previous measurements. We also explain how the flavor dependence of quark fragmentation functions and the gluon function are separated by using measurements at different Q2 values. In particular, the electric and weak charges are different depending on the quark type, so that a light-quark flavor separation also became possible in principle due to the precise data at both s≃10.5 and 91.2 GeV.
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