Far Ultraviolet Observations of the Dwarf Nova VW Hyi in Quiescence

We present a 904-1183 A spectrum of the dwarf nova VW Hydri taken with the Far Ultraviolet Spectroscopic Explorer during quiescence, eleven days after a normal outburst, when the underlying white dwarf accreter is clearly exposed in the far ultraviolet. However, model fitting show that a uniform temperature white dwarf does not reproduce the overall spectrum, especially at the shortest wavelengths. A better approximation to the spectrum is obtained with a model consisting of a white dwarf and a rapidly rotating ``accretion belt''. The white dwarf component accounts for 83% of the total flux, has a temperature of 23,000K, a v sin i = 400 km/s, and a low carbon abundance. The best-fit accretion belt component accounts for 17% of the total flux, has a temperature of about 48,000-50,000K, and a rotation rate Vrot sin i around 3,000-4,000 km/s. The requirement of two components in the modeling of the spectrum of VW Hyi in quiescence helps to resolve some of the differences in interpretation of ultraviolet spectra of VW Hyi in quiescence. However, the physical existence of a second component (and its exact nature) in VW Hyi itself is still relatively uncertain, given the lack of better models for spectra of the inner disk in a quiescent dwarf nova.Comment: 6 figures, 10 printed page in the journal, to appear in APJ, 1 Sept. 2004 issue, vol. 61

Hadron widths in mixed-phase matter

We derive classically an expression for a hadron width in a two-phase region of hadron gas and quark-gluon plasma (QGP). The presence of QGP gives hadrons larger widths than they would have in a pure hadron gas. We find that the $\phi$ width observed in a central Au+Au collision at $\sqrt{s}=200$ GeV/nucleon is a few MeV greater than the width in a pure hadron gas. The part of observed hadron widths due to QGP is approximately proportional to $(dN/dy)^{-1/3}$.Comment: 8 pages, latex, no figures, KSUCNR-002-9

Color-octet mechanism and J/psi polarization at LEP

Polarized heavy quarkonium productions in $Z^0$ decays are considered. We find that polarizations of the produced quarkonia are independent of that of the parent Z^0 provided that one considers the energy distribution or the total production rate. Produced J/psi's via the color-octet and the color- singlet mechanisms are expected to be 19% and 29% longitudinally polarized, respectively. The energy dependence of eta_{1,8}(x)=\frac{dGamma_{1,8}^L}{dx} /\frac{dGamma_{1,8}}{d x} is very sensitive to the production mechanism, and therefore the measurement of \eta(x)_exp will be an independent probe of the color-octet mechanism.Comment: 15 pages, minor changes, version to be published in Phys. Rev.

Arterial Spin Labeling Perfusion of the Brain: Emerging Clinical Applications

Arterial spin labeling (ASL) is a magnetic resonance (MR) imaging technique used to assess cerebral blood flow noninvasively by magnetically labeling inflowing blood. In this article, the main labeling techniques, notably pulsed and pseudocontinuous ASL, as well as emerging clinical applications will be reviewed. In dementia, the pattern of hypoperfusion on ASL images closely matches the established patterns of hypometabolism on fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) images due to the close coupling of perfusion and metabolism in the brain. This suggests that ASL might be considered as an alternative for FDG, reserving PET to be used for the molecular disease-specific amyloid and tau tracers. In stroke, ASL can be used to assess perfusion alterations both in the acute and the chronic phase. In arteriovenous malformations and dural arteriovenous fistulas, ASL is very sensitive to detect even small degrees of shunting. In epilepsy, ASL can be used to assess the epileptogenic focus, both in peri- and interictal period. In neoplasms, ASL is of particular interest in cases in which gadolinium-based perfusion is contraindicated (eg, allergy, renal impairment) and holds promise in differentiating tumor progression from benign causes of enhancement. Finally, various neurologic and psychiatric diseases including mild traumatic brain injury or posttraumatic stress disorder display alterations on ASL images in the absence of visualized structural changes. In the final part, current limitations and future developments of ASL techniques to improve clinical applicability, such as multiple inversion time ASL sequences to assess alterations of transit time, reproducibility and quantification of cerebral blood flow, and to measure cerebrovascular reserve, will be reviewed

Partonic effects on anisotropic flows at RHIC

We report recent results from a multiphase transport (AMPT) model on the azimuthal anisotropies of particle momentum distributions in heavy ion collisions at the Relativistic Heavy Ion Collider. These include higher-order anisotropic flows and their scaling, the rapidity dependence of anisotropic flows, and the elliptic flow of charm quarks.Comment: 7 pages, 5 figures, talk given at "Hot Quarks 2004", July 18-24, 2004, Taos Valley, NM, US

Antrodia cinnamomea reduces obesity and modulates the gut microbiota in high-fat diet-fed mice.

BackgroundObesity is associated with gut microbiota dysbiosis, disrupted intestinal barrier and chronic inflammation. Given the high and increasing prevalence of obesity worldwide, anti-obesity treatments that are safe, effective and widely available would be beneficial. We examined whether the medicinal mushroom Antrodia cinnamomea may reduce obesity in mice fed with a high-fat diet (HFD).MethodsMale C57BL/6J mice were fed a HFD for 8 weeks to induce obesity and chronic inflammation. The mice were treated with a water extract of A. cinnamomea (WEAC), and body weight, fat accumulation, inflammation markers, insulin sensitivity and the gut microbiota were monitored.ResultsAfter 8 weeks, the mean body weight of HFD-fed mice was 39.8±1.2 g compared with 35.8±1.3 g for the HFD+1% WEAC group, corresponding to a reduction of 4 g or 10% of body weight (P<0.0001). WEAC supplementation reduced fat accumulation and serum triglycerides in a statistically significant manner in HFD-fed mice. WEAC also reversed the effects of HFD on inflammation markers (interleukin-1β, interleukin-6, tumor necrosis factor-α), insulin resistance and adipokine production (leptin and adiponectin). Notably, WEAC increased the expression of intestinal tight junctions (zonula occludens-1 and occludin) and antimicrobial proteins (Reg3g and lysozyme C) in the small intestine, leading to reduced blood endotoxemia. Finally, WEAC modulated the composition of the gut microbiota, reducing the Firmicutes/Bacteroidetes ratio and increasing the level of Akkermansia muciniphila and other bacterial species associated with anti-inflammatory properties.ConclusionsSupplementation with A. cinnamomea produces anti-obesogenic, anti-inflammatory and antidiabetic effects in HFD-fed mice by maintaining intestinal integrity and modulating the gut microbiota

Color Octet Contribution to J/psi Photoproduction Asymmetries

We investigate $J/\psi$ photoproduction asymmetries in the framework of the NRQCD factorization approach. It is shown that the color octet contribution leads to large uncertainties in the predicted asymmetries which rules out the possibility to precisely measure the gluon polarization in the nucleon through this final state. For small values of the color octet parameters being compatible with $J/\psi$ photoproduction data it appears possible that a measurement of $J/\psi$ asymmetries could provide a new test for the NRQCD factorization approach, on one hand, or a measurement of the polarized gluon distribution from low inelasticity events $(z<0.7)$, on the otherComment: 12 pages, LaTeX, with 6 figs. Final version published in Phys.Rev.

Feedback Heating by Cosmic Rays in Clusters of Galaxies

Recent observations show that the cooling flows in the central regions of galaxy clusters are highly suppressed. Observed AGN-induced cavities/bubbles are a leading candidate for suppressing cooling, usually via some form of mechanical heating. At the same time, observed X-ray cavities and synchrotron emission point toward a significant non-thermal particle population. Previous studies have focused on the dynamical effects of cosmic-ray pressure support, but none have built successful models in which cosmic-ray heating is significant. Here we investigate a new model of AGN heating, in which the intracluster medium is efficiently heated by cosmic-rays, which are injected into the ICM through diffusion or the shredding of the bubbles by Rayleigh-Taylor or Kelvin-Helmholtz instabilities. We include thermal conduction as well. Using numerical simulations, we show that the cooling catastrophe is efficiently suppressed. The cluster quickly relaxes to a quasi-equilibrium state with a highly reduced accretion rate and temperature and density profiles which match observations. Unlike the conduction-only case, no fine-tuning of the Spitzer conduction suppression factor f is needed. The cosmic ray pressure, P_c/P_g <~ 0.1 and dP_c/dr <~ 0.1 \rho g, is well within observational bounds. Cosmic ray heating is a very attractive alternative to mechanical heating, and may become particularly compelling if GLAST detects the gamma-ray signature of cosmic-rays in clusters.Comment: Revised version accepted for publication in MNRAS. Significantly expanded discussion and new simulations exploring parameter space/model robustness; conclusions unchange

Non-factorizable contribution in nonleptonic weak interactions of K mesons

Two pion decays of K mesons, K_L-K_S mass difference, two photon and the Dalitz decays of K_L are studied systematically by assuming that their amplitude is given by a sum of factorizable and non-factorizable ones. The former is estimated by using a naive factorization while the latter is assumed to be dominated by dynamical contributions of various hadron states.Comment: 23 pages,1 figur

A fast ILP-based Heuristic for the robust design of Body Wireless Sensor Networks

We consider the problem of optimally designing a body wireless sensor network, while taking into account the uncertainty of data generation of biosensors. Since the related min-max robustness Integer Linear Programming (ILP) problem can be difficult to solve even for state-of-the-art commercial optimization solvers, we propose an original heuristic for its solution. The heuristic combines deterministic and probabilistic variable fixing strategies, guided by the information coming from strengthened linear relaxations of the ILP robust model, and includes a very large neighborhood search for reparation and improvement of generated solutions, formulated as an ILP problem solved exactly. Computational tests on realistic instances show that our heuristic finds solutions of much higher quality than a state-of-the-art solver and than an effective benchmark heuristic.Comment: This is the authors' final version of the paper published in G. Squillero and K. Sim (Eds.): EvoApplications 2017, Part I, LNCS 10199, pp. 1-17, 2017. DOI: 10.1007/978-3-319-55849-3\_16. The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-55849-3_1