1,662 research outputs found
Nuclear Physics from lattice QCD at strong coupling
We study numerically the strong coupling limit of lattice QCD with one flavor
of massless staggered quarks. We determine the complete phase diagram as a
function of temperature and chemical potential, including a tricritical point.
We clarify the nature of the low temperature dense phase, which is strongly
bound nuclear matter. This strong binding is explained by the nuclear
potential, which we measure. Finally, we determine, from this first-principle
limiting case of QCD, the masses of atomic nuclei up to A=12 "carbon".Comment: 4 pages, 5 figures; v2: references added, minor changes, published
versio
Non-hermitian Exact Local Bosonic Algorithm for Dynamical Quarks
We present an exact version of the local bosonic algorithm for the simulation
of dynamical quarks in lattice QCD. This version is based on a non-hermitian
polynomial approximation of the inverse of the quark matrix. A Metropolis test
corrects the systematic errors. Two variants of this test are presented. For
both of them, a formal proof is given that this Monte Carlo algorithm converges
to the right distribution. Simulation data are presented for different lattice
parameters. The dynamics of the algorithm and its scaling in lattice volume and
quark mass are investigated.Comment: 32 pages, LaTex, 8 ps figure
Envelope structure of deeply embedded young stellar objects in the Serpens Molecular Cloud
Aperture synthesis and single-dish (sub) millimeter molecular lines and
continuum observations reveal in great detail the envelope structure of deeply
embedded young stellar objects (SMM1, SMM2, SMM3, SMM4) in the densely
star-forming Serpens Molecular Cloud. Resolved millimeter continuum emission
constrains the density structure to a radial power law with index -2.0 +/- 0.5,
and envelope masses of 8.7, 3.0, and 5.3 M_sol for SMM1, SMM3, and SMM4. The
core SMM2 does not seem to have a central condensation and may not have formed
a star yet. The molecular line observations can be described by the same
envelope model, if an additional, small amount of warm (100 K) material is
included. This probably corresponds to the inner few hundred AU of the envelope
were the temperature is high. In the interferometer beam, the molecular lines
reveal the inner regions of the envelopes, as well as interaction of the
outflow with the surrounding envelope. Bright HCO+ and HCN emission outlines
the cavities, while SiO and SO trace the direct impact of the outflow on
ambient gas. Taken together, these observations provide a first comprehensive
view of the physical and chemical structure of the envelopes of deeply embedded
young stellar objects in a clustered environment on scales between 1000 and
10,000 AU.Comment: 46 pages, incl. 12 postscript figures, uses ApJ latex and psfig
macro
Development and assessment of postcranial sex estimation methods for a Guatemalan population
This study tests whether postcranial sex estimation methods generated from Hispanic, and mainly Mexican samples, can be successfully applied to other increasingly common migrant populations from Central America. We use a sample of postcranial data from a modern (1980s) Guatemalan Maya sample (n = 219). Results indicate a decrease in classification accuracies for previously established univariate methods when applied to the Guatemalan study sample, specifically for males whose accuracies ranged from 30 to 84%. This bias toward inaccuracies for Guatemalan males is associated with the smaller skeletal sizes for the Guatemalan sample as compared to the samples used in the tested sex estimation methods. In contrast, the tested multivariate discriminant function classification yielded less sex bias and improved classification accuracies ranging from 82 to 89%. Our results highlight which of the tested univariate and multivariate methods reach acceptable levels for accuracy for sex estimation of cases where the region of origin may include Guatemala
A first look at maximally twisted mass lattice QCD calculations at the physical point
In this contribution, a first look at simulations using maximally twisted
mass Wilson fermions at the physical point is presented. A lattice action
including clover and twisted mass terms is presented and the Monte Carlo
histories of one run with two mass-degenerate flavours at a single lattice
spacing are shown. Measurements from the light and heavy-light pseudoscalar
sectors are compared to previous results and their phenomenological
values. Finally, the strategy for extending simulations to is
outlined.Comment: presented at the 31st International Symposium on Lattice Field Theory
(Lattice 2013), 29 July - 3 August 2013, Mainz, German
Unknotting night-time muscle cramp: a survey of patient experience, help-seeking behaviour and perceived treatment effectiveness
Background: Night-time calf cramping affects approximately 1 in 3 adults. The aim of this study was to explore the experience of night-time calf cramp; if and where people seek treatment advice; and perceived treatment effectiveness. Methods: 80 adults who experienced night-time calf cramp at least once per week were recruited from the Hunter region, NSW, Australia through newspaper, radio and television advertisements. All participants completed a pilot-tested survey about muscle cramp. Quantitative data were analysed with independent-sample t-tests, Chi square tests and Fisherâs tests. Qualitative data were transcribed and sorted into categories to identify themes. Results: Median recalled age of first night-time calf cramp was 50 years. Most participants recalled being awoken from sleep by cramping, and experiencing cramping of either calf muscle, calf-muscle soreness in the days following cramp and cramping during day-time. Despite current therapies, mean usual pain intensity was 66 mm on a 100 mm visual analogue scale. Participants described their cramps as being âunbearableâ, âunmanageableâ and âcruelâ. One participant stated that âsometimes I just wish I could cut my legs openâ and another reported âgetting about 2h sleep a night due to crampsâ. Most participants had sought advice about their night-time calf cramps from a health professional. Participants identified 49 different interventions used to prevent night-time calf cramp. Of all treatment ratings, 68% described the intervention used to prevent cramp as being âuselessâ or of âa little helpâ. Of 14 participants who provided additional information regarding their use of quinine, eight had a current prescription of quinine for muscle cramp at the time of the survey. None had been asked by their prescribing doctor to stop using quinine. Conclusion: Night time calf cramps typically woke sufferers from sleep, affected either leg and caused ongoing pain. Most participants experienced little or no relief with current therapies used to prevent muscle cramp. Most people who were taking quinine for muscle cramp were unaware that the Australian Therapeutic Goods Administration withdrew support of quinine for muscle cramp in 2004 due to the risk of thrombocytopaenia. Case-control studies are required to identify therapeutic targets so that clinical trials can evaluate safe interventions to prevent recurrent cramp
World small animal veterinary association renal pathology initiative: classification of glomerular diseases in dogs
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