Histograms in heavy-quark QCD at finite temperature and density

We study the phase structure of lattice QCD with heavy quarks at finite temperature and density by a histogram method. We determine the location of the critical point at which the first-order deconfining transition in the heavy-quark limit turns into a crossover at intermediate quark masses through a change of the shape of the histogram under variation of coupling parameters. We estimate the effect of the complex phase factor which causes the sign problem at finite density, and show that, in heavy-quark QCD, the effect is small around the critical point. We determine the critical surface in 2+1 flavor QCD in the heavy-quark region at all values of the chemical potential mu including mu=infty.Comment: 26 pages, 21 figures, 1 tabl

Ab-initio simulations of higher Miller index Si:SiO<inf>2</inf> interfaces for fin field effect transistor and nanowire transistors

Models of three representative higher Miller index interfaces, Si(310):SiO2, Si(410):SiO2, and Si(331):SiO2, have been built by an ab-initio molecular dynamics method. We show that each interface can be made as a fully bonded network without any defects and has a reasonable electronic structure for use in fin field effect transistors or gate-all-around nanowire devices. The differences in numbers of oxygen bridges are attributed to the intermediate sub-oxide components and the atomic step structure. The interface bonding schemes to passivate different densities of dangling bonds on different facets are also analyzed.This is the accepted manuscript. The final version is available at scitation.aip.org/content/aip/journal/jap/119/5/10.1063/1.4941272

An experimental and computational investigation of the flow field about a transonic airfoil in supercritical flow with turbulent boundary-layer separation

A combined experimental and computational research program is described for testing and guiding turbulence modeling within regions of separation induced by shock waves incident in turbulent boundary layers. Specifically, studies are made of the separated flow the rear portion of an 18%-thick circular-arc airfoil at zero angle of attack in high Reynolds number supercritical flow. The measurements include distributions of surface static pressure and local skin friction. The instruments employed include highfrequency response pressure cells and a large array of surface hot-wire skin-friction gages. Computations at the experimental flow conditions are made using time-dependent solutions of ensemble-averaged Navier-Stokes equations, plus additional equations for the turbulence modeling

Causes and Outcomes of Spontaneous Pneumothoraces in Solid Tumor Cancer Patients: An Update for the Medical Oncologist

PurposeDefined as lung collapse in the absence of a recent invasive thoracic procedure, a spontaneous pneumothorax can be a catastrophic event, leading to abrupt shortness of breath, chest pain, hypotension, and occasionally death. A dearth of present day information on this entity in solid tumor cancer patients prompted this single-institution retrospective study on current causes and outcomes.MethodsAll patients with diagnoses of “spontaneous pneumothorax” and “cancer” between 1990 and 2004 had their records retrieved and reviewed. Among 546 patients with a diagnosis of spontaneous pneumothorax, only 25 (5%) met predefined inclusion criteria that included an antecedent diagnosis of an invasive solid tumor malignancy. Lung (n = 5) and bladder cancer (n = 4) were the most common malignancies; eight patients had received radiation and one had received carmustine. Of note, 78% were smokers, 13 had chronic obstructive pulmonary disease, and 12 had no known active cancer at the time of the pneumothorax.ResultsPneumothorax management was associated with great morbidity, including hospitalization in 24 patients and chest tube placement and/or surgery in most patients. Median survival for the group as a whole was 31 months, but patients with known active cancer tended to do poorly, with only a 3-month median survival.ConclusionA spontaneous pneumothorax is rare, and patients with known active cancer tend to do poorly. However, even patients with no known active cancer are at risk, perhaps in part from smoking. The fact that patients with no known active cancer can live for years after this event suggests that the pneumothorax should not be assumed to be related to cancer recurrence, that cancer restaging is not always mandatory, and that there is justification for managing the pneumothorax in this subgroup aggressively

A Study Of Surface Dynamics Of Polymers. II. Investigation By Plasma Surface Implantation Of Fluorine–containing Moieties

Macromolecules at the surface of a polymeric solid have considerable mobility, and the specific arrangement of functional groups of macromolecules at the surface is dictated by the environmental conditions in which the surface is placed. Consequently, the change of environmental conditions, such as immersion in water or placement in a biological surrounding, could cause a considerable degree of change in the surface characteristics of a polymer from those evaluated in the laboratory against ambient air. The mobile nature of a polymer surface can be investigated by surface‐implanting fluorine‐containing moieties, mainly—CF3, by the plasma implantation technique and following the disappearance and reappearance of fluorine atoms on the surface. The disappearance rates (based on the immersion time in water at room temperature) of ESCA F1s signals, the decay rates of (advancing) contact angle of water, and the recovery of these values on heat treatment of water‐immersed samples were measured as a function of crystallinity of polymer samples (at three levels of crystallinity) for poly (ethylene terephthalate) and nylon 6. Copyright © 1988 John Wiley & Sons, Inc

The counterbend phenomenon in flagellar axonemes and cross-linked filament bundles

Recent observations of flagellar counterbend in sea urchin sperm show that the mechanical induction of curvature in one part of a passive flagellum induces a compensatory countercurvature elsewhere. This apparent paradoxical effect cannot be explained using the standard elastic rod theory of Euler and Bernoulli, or even the more general Cosserat theory of rods. Here, we develop a geometrically exact mechanical model to describe the statics of microtubule bundles that is capable of predicting the curvature reversal events observed in eukaryotic flagella. This is achieved by allowing the interaction of deformations in different material directions, by accounting not only for structural bending, but also for the elastic forces originating from the internal cross-linking mechanics. Large-amplitude static configurations can be described analytically, and an excellent match between the model and the observed counterbend deformation was found. This allowed a simultaneous estimation of multiple sperm flagellum material parameters, namely the cross-linking sliding resistance, the bending stiffness, and the sperm head junction compliance ratio. We further show that small variations on the empirical conditions may induce discrepancies for the evaluation of the flagellar material quantities, so that caution is required when interpreting experiments. Finally, our analysis demonstrates that the counterbend emerges as a fundamental property of sliding resistance in cross-linked filamentous polymer bundles, which also suggests that cross-linking proteins may contribute to the regulation of the flagellar waveform in swimming sperm via counterbend mechanics

Projectile fragmentation reactions and production of nuclei near the neutron drip-line

The reaction mechanism of projectile fragmentation at intermediate energies has been investigated observing the target dependence of the production cross sections of very neutron-rich nuclei. Measurement of longitudinal momentum distributions of projectile-like fragments within a wide range of fragment mass and its charge was performed using a hundred-MeV/n $^{40}$Ar beam incident on Be and Ta targets. By measurement of fragment momentum distribution, a parabolic mass dependence of momentum peak shift was observed in the results of both targets, and a phenomenon of light-fragment acceleration was found only in the Be-target data. The analysis of production cross sections revealed an obvious enhancement of the target dependence except target size effect when the neutron excess is increased. This result implies the breakdown of factorization (BOF) of production cross sections for very neutron-rich nuclei near the drip line.Comment: 16 pages, 18 figures, submitted to Phys. Rev.

Current patterns and magnetic impurities in time-reversal breaking superconductor

We study the impurity effect in the time reversal symmetry (${\cal T}$) breaking superconductor based on the Bogoliubov-de Gennes (BdG) equations. In ${\cal T}$-violating superconductors, spontaneous currents are induced around the impurity. The current patterns around the impurity reflect the structures of the Cooper pairs. We investigate impurity problem numerically for two kinds of ${\cal T}$ violating superconductors $(p_{x}\pm {\rm i}p_{y}$ and $d+{\rm i}s)$ and investigate the currents around the impurity. We also study the effects of the magnetic impurity in p-wave ($p_{x}\pm {\rm i}p_{y}$) superconductor, especially in view of the zero-energy crossing of energy levels related to the phase transition of the ground state.Comment: 18 page