356 research outputs found
Nuclear symmetry potential in the relativistic impulse approximation
Using the relativistic impulse approximation with the Love-Franey \textsl{NN}
scattering amplitude developed by Murdock and Horowitz, we investigate the
low-energy (100 MeV MeV) behavior of the nucleon
Dirac optical potential, the Schr\"{o}dinger-equivalent potential, and the
nuclear symmetry potential in isospin asymmetric nuclear matter. We find that
the nuclear symmetry potential at fixed baryon density decreases with
increasing nucleon energy. In particular, the nuclear symmetry potential at
saturation density changes from positive to negative values at nucleon kinetic
energy of about 200 MeV. Furthermore,the obtained energy and density dependence
of the nuclear symmetry potential is consistent with those of the isospin- and
momentum-dependent MDI interaction with , which has been found to describe
reasonably both the isospin diffusion data from heavy-ion collisions and the
empirical neutron-skin thickness of Pb.Comment: 8 pages, 5 figures, revised version to appear in PR
A Case of Swallow Syncope Associated With Cold Beverage Ingestion
Swallow syncope (also known as deglutition syncope) is a relatively rare type of syncope that is treatable if diagnosed correctly. We report a case of a 39-year-old man with recurrent swallow syncope. The patient did not have structural heart disease. He developed a complete atrioventricular block upon drinking a cold beverage (Chilsung cider) while undergoing a repeated head-up tilt test. The patient was advised to avoid cold beverages and has been symptom free for 5 months
Magnetic Reconnection with Asymmetry in the Outflow Direction
Magnetic reconnection with asymmetry in the outflow direction occurs in the
Earth's magnetotail, coronal mass ejections, flux cancellation events,
astrophysical disks, spheromak merging experiments, and elsewhere in nature and
the laboratory. A control volume analysis is performed for the case of steady
antiparallel magnetic reconnection with asymmetric downstream pressure, which
is used to derive scaling relations for the outflow velocity from each side of
the current sheet and the reconnection rate. Simple relationships for outflow
velocity are presented for the incompressible case and the case of symmetric
downstream pressure but asymmetric downstream density. Asymmetry alone is not
found to greatly affect the reconnection rate. The flow stagnation point and
magnetic field null do not coincide in a steady state unless the pressure
gradient is negligible at the flow stagnation point.Comment: 12 pages, 8 figures. Submitted to JGR. Any comments will be
appreciate
Plasmoids in Reconnecting Current Sheets: Solar and Terrestrial Contexts Compared
Magnetic reconnection plays a crucial role in violent energy conversion
occurring in the environments of high electrical conductivity, such as the
solar atmosphere, magnetosphere, and fusion devices. We focus on the
morphological features of the process in two different environments, the solar
atmosphere and the geomagnetic tail. In addition to indirect evidence that
indicates reconnection in progress or having just taken place, such as auroral
manifestations in the magnetosphere and the flare loop system in the solar
atmosphere, more direct evidence of reconnection in the solar and terrestrial
environments is being collected. Such evidence includes the reconnection inflow
near the reconnecting current sheet, and the outflow along the sheet
characterized by a sequence of plasmoids. Both turbulent and unsteady
Petschek-type reconnection processes could account for the observations. We
also discuss other relevant observational consequences of both mechanisms in
these two settings. While on face value, these are two completely different
physical environments, there emerge many commonalities, for example, an Alfven
speed of the same order of magnitude, a key parameter determining the
reconnection rate. This comparative study is meant as a contribution to current
efforts aimed at isolating similarities in processes occurring in very
different contexts in the heliosphere, and even in the universe.Comment: 21 pages, 9 figures, in press at J. Geophys. Res. (Space Physics),
for the special NESSC section on Comparative Aspects of Magnetic Reconnectio
Cross-Attraction between an Exotic and a Native Pine Bark Beetle: A Novel Invasion Mechanism?
Aside from the ecological impacts, invasive species fascinate ecologists because of the unique opportunities that invasives offer in the study of community ecology. Some hypotheses have been proposed to illustrate the mechanisms that allow exotics to become invasive. However, positive interactions between exotic and native insects are rarely utilized to explain invasiveness of pests.Here, we present information on a recently formed association between a native and an exotic bark beetle on their shared host, Pinus tabuliformis, in China. In field examinations, we found that 35-40% of P. tabuliformis attacked by an exotic bark beetle, Dendroctonus valens, were also attacked by a native pine bark beetle, Hylastes parallelus. In the laboratory, we found that the antennal and walking responses of H. parallelus to host- and beetle-produced compounds were similar to those of the exotic D. valens in China. In addition, D. valens was attracted to volatiles produced by the native H. parallelus.We report, for the first time, facilitation between an exotic and a native bark beetle seems to involve overlap in the use of host attractants and pheromones, which is cross-attraction. The concept of this interspecific facilitation could be explored as a novel invasive mechanism which helps explain invasiveness of not only exotic bark beetles but also other introduced pests in principle. The results reported here also have particularly important implications for risk assessments and management strategies for invasive species
Expected Performance of the ATLAS Experiment - Detector, Trigger and Physics
A detailed study is presented of the expected performance of the ATLAS
detector. The reconstruction of tracks, leptons, photons, missing energy and
jets is investigated, together with the performance of b-tagging and the
trigger. The physics potential for a variety of interesting physics processes,
within the Standard Model and beyond, is examined. The study comprises a series
of notes based on simulations of the detector and physics processes, with
particular emphasis given to the data expected from the first years of
operation of the LHC at CERN
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Randomised control trial of the effectiveness of an integrated psychosocial health promotion intervention aimed at improving health and reducing substance use in established psychosis (IMPaCT)
© 2017 The Author(s). Background: People with psychosis have a reduced life expectancy of 10-20years, largely due to cardiovascular disease. This trial aimed to determine the effectiveness of a modular health promotion intervention (IMPaCT Therapy) in improving health and reducing cardiovascular risk in psychosis. Methods: A multicentre, two arm, parallel cluster RCT was conducted across five UK mental health NHS trusts. Community care coordinators (CC) were randomly assigned to training and supervision in delivering IMPaCT Therapy or treatment as usual (TAU) to current patients with psychosis (cluster). The primary outcome was the physical and mental health subscales of the Short form-36 (SF-36) questionnaire. Results: Of 104 care coordinators recruited, 52 (with 213 patients) were randomised to deliver IMPaCT therapy and 52 (with 193 patients) randomised to TAU. Of 406 patients, 318 (78%) and 301 (74%) attended 12- and 15-month follow-up respectively. IMPaCT therapy showed no significant effect on the physical or mental health component SF-36 scores versus TAU at 12 or 15months. No effect was observed for cardiovascular risk indicators, except for HDL cholesterol, which improved more with IMPACT therapy than TAU (Treatment effect (95% CI); 0.085 (0.007 to 0.16); p= 0.034). The 22% of patients who received > 180min of IMPACT Therapy in addition to usual care achieved a greater reduction in waist circumference than did controls, which was clinically significant. Conclusion: Training and supervising community care coordinators to use IMPaCT therapy in patients with psychosis is insufficient to significantly improve physical or mental health quality of life. The search for effective, pragmatic interventions deliverable in health care services continues. Trial registration: The trial was retrospectively registered with ISRCTN registry on 23/4/2010 at ISRCTN58667926 ; recruitment started on 01/03/2010 with first randomization on 09.08.2010 ISRCTN58667926
Eradication of Metastatic Renal Cell Carcinoma after Adenovirus-Encoded TNF-Related Apoptosis-Inducing Ligand (TRAIL)/CpG Immunotherapy
Despite evidence that antitumor immunity can be protective against renal cell carcinoma (RCC), few patients respond objectively to immunotherapy and the disease is fatal once metastases develop. We asked to what extent combinatorial immunotherapy with Adenovirus-encoded murine TNF-related apoptosis-inducing ligand (Ad5mTRAIL) plus CpG oligonucleotide, given at the primary tumor site, would prove efficacious against metastatic murine RCC. To quantitate primary renal and metastatic tumor growth in mice, we developed a luciferase-expressing Renca cell line, and monitored tumor burdens via bioluminescent imaging. Orthotopic tumor challenge gave rise to aggressive primary tumors and lung metastases that were detectable by day 7. Intra-renal administration of Ad5mTRAIL+CpG on day 7 led to an influx of effector phenotype CD4 and CD8 T cells into the kidney by day 12 and regression of established primary renal tumors. Intra-renal immunotherapy also led to systemic immune responses characterized by splenomegaly, elevated serum IgG levels, increased CD4 and CD8 T cell infiltration into the lungs, and elimination of metastatic lung tumors. Tumor regression was primarily dependent upon CD8 T cells and resulted in prolonged survival of treated mice. Thus, local administration of Ad5mTRAIL+CpG at the primary tumor site can initiate CD8-dependent systemic immunity that is sufficient to cause regression of metastatic lung tumors. A similar approach may prove beneficial for patients with metastatic RCC
Vitamin D and Its Role During Pregnancy in Attaining Optimal Health of Mother and Fetus
Despite its discovery a hundred years ago, vitamin D has emerged as one of the most controversial nutrients and prohormones of the 21st century. Its role in calcium metabolism and bone health is undisputed but its role in immune function and long-term health is debated. There are clear indicators from in vitro and animal in vivo studies that point to vitamin D’s indisputable role in both innate and adaptive immunity; however, the translation of these findings to clinical practice, including the care of the pregnant woman, has not occurred. Until recently, there has been a paucity of data from randomized controlled trials to establish clear cut beneficial effects of vitamin D supplementation during pregnancy. An overview of vitamin metabolism, states of deficiency, and the results of recent clinical trials conducted in the U.S. are presented with an emphasis on what is known and what questions remain to be answered
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