Transition Density and Pressure at the Inner Edge of Neutron Star Crusts

Using the nuclear symmetry energy that has been recently constrained by the isospin diffusion data in intermediate-energy heavy ion collisions, we have studied the transition density and pressure at the inner edge of neutron star crusts, and they are found to be 0.040 fm$^{-3}$ $\leq \rho_{t}\leq 0.065$ fm$^{-3}$ and 0.01 MeV/fm$^{3}$ $\leq P_{t}\leq 0.26$ MeV/fm$^{3}$, respectively, in both the dynamical and thermodynamical approaches. We have also found that the widely used parabolic approximation to the equation of state of asymmetric nuclear matter gives significantly higher values of core-crust transition density and pressure, especially for stiff symmetry energies. With these newly determined transition density and pressure, we have obtained an improved relation between the mass and radius of neutron stars.Comment: 7 pages, 3 figures, proceeding of "The International Workshop on Nuclear Dynamics in Heavy-Ion Reactions and the Symmetry Energy (IWND2009)

Objective measurement for surgical skill evaluation

The purpose of this study was to identify measurable parameters that can be used to quantitatively assess psychomotor skills, specifically for surgical skills assessment. Sixteen participants were recruited from two groups: surgeon (N = 5) and non-surgeon (N = 11). Both groups underwent a psychomotor test using a custom developed ‘Green Target’ module which was designed using a virtual reality system. Six parameters were used to compare the psychomotor skills between the two groups. The results showed that surgeons outperformed the non-surgeons in five out of six parameters investigated and the difference was statistically significant. The average normalised comparison values for surgeons and non-surgeons for motion path accuracy, motion path precision, economy of movement, end-point accuracy and end-point precision were 0.13±0.12 and 0.17±0.12, 0.08±0.11 and 0.10±0.10, 3.76±1.76 and 4.08±2.24, 0.12±0.10 and 0.17±0.11, 0.04±0.10 and 0.07±s0.10 respectively, p < 0.05). These parameters can potentially be used to objectively assess the performance of surgical skill

Use of gas liquid chromatography in combination with pancreatic lipolysis and multivariate data analysis techniques for identification of lard contamination in some vegetable oils

A study was conducted to investigate the use of gas liquid chromatography (GLC) to identify lard (LD) contamination in palm oil (PO), palm kernel oil (PKO), and canola oil (CLO). Vegetable oils were deliberately adulterated with animal fats such as LD, beef tallow (BT), and chicken fat (CF) in varying proportions. In order to monitor the fatty acid (FA) compositional changes due to adulteration, GLC analyses of fatty acid methyl esters (FAME) were performed on 2-monoacylglycerol (2-MG) and neutral triacylglycerol (TAG) isolated from each sample. For the evaluation of FA data, multivariate statistical techniques were employed. The results showed that canonical discriminant (CANDISC) analysis was the most effective technique for discriminating LD-adulterated samples from those adulterated with other animal fats. Additionally, mathematical equations obtained by simple regression analysis could be used for quantification of LD contents in admixtures

Resolving Vega and the inclination controversy with CHARA/MIRC

Optical and infrared interferometers definitively established that the photometric standard Vega (alpha Lyrae) is a rapidly rotating star viewed nearly pole-on. Recent independent spectroscopic analyses could not reconcile the inferred inclination angle with the observed line profiles, preferring a larger inclination. In order to resolve this controversy, we observed Vega using the six-beam Michigan Infrared Combiner on the Center for High Angular Resolution Astronomy Array. With our greater angular resolution and dense (u,v)-coverage, we find Vega is rotating less rapidly and with a smaller gravity darkening coefficient than previous interferometric results. Our models are compatible with low photospheric macroturbulence and also consistent with the possible rotational period of ~0.71 days recently reported based on magnetic field observations. Our updated evolutionary analysis explicitly incorporates rapid rotation, finding Vega to have a mass of 2.15+0.10_-0.15 Msun and an age 700-75+150 Myrs, substantially older than previous estimates with errors dominated by lingering metallicity uncertainties (Z=0.006+0.003-0.002).Comment: Accepted for publication in ApJ Letter

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

Developing 21st century accreditation standards for teaching hospitals: the Taiwan experience

<p>Abstract</p> <p>Background</p> <p>The purpose of this study is to establish teaching hospital accreditation standards anew with the hope that Taiwan's teaching hospitals can live up to the expectations of our society and ensure quality teaching.</p> <p>Methods</p> <p>The development process lasted two years, 2005-2006, and was separated into three stages. The first stage centered on leadership meetings and consensus building, the second on drafting the new standards with expert focus groups, and the third on a pilot study and subsequent revision.</p> <p>Results</p> <p>Our new teaching hospital accreditation standards have six categories and 95 standards as follows: educational resources (20 items), teaching and training plans and outcomes (42 items), research and results (9 items), development of clinical faculty and continuing education (8 items), academic exchanges and community education (8 items), and administration (8 items).</p> <p>Conclusions</p> <p>The new standards have proven feasible and posed reasonable challenges in the pilot study. We hope the new standards will strengthen teaching and research, and improve the quality of hospital services at the same time.</p

The FERONIA Receptor Kinase Maintains Cell-Wall Integrity during Salt Stress through Ca2+ Signaling

Cells maintain integrity despite changes in their mechanical properties elicited during growth and environmental stress. How cells sense their physical state and compensate for cell-wall damage is poorly understood, particularly in plants. Here we report that FERONIA (FER), a plasma-membrane-localized receptor kinase from Arabidopsis, is necessary for the recovery of root growth after exposure to high salinity, a widespread soil stress. The extracellular domain of FER displays tandem regions of homology with malectin, an animal protein known to bind di-glucose in vitro and important for protein quality control in the endoplasmic reticulum. The presence of malectin-like domains in FER and related receptor kinases has led to widespread speculation that they interact with cell-wall polysaccharides and can potentially serve a wall-sensing function. Results reported here show that salinity causes softening of the cell wall and that FER is necessary to sense these defects. When this function is disrupted in the fer mutant, root cells explode dramatically during growth recovery. Similar defects are observed in the mur1 mutant, which disrupts pectin cross-linking. Furthermore, fer cell-wall integrity defects can be rescued by treatment with calcium and borate, which also facilitate pectin cross-linking. Sensing of these salinity-induced wall defects might therefore be a direct consequence of physical interaction between the extracellular domain of FER and pectin. FER-dependent signaling elicits cell-specific calcium transients that maintain cell-wall integrity during salt stress. These results reveal a novel extracellular toxicity of salinity, and identify FER as a sensor of damage to the pectin-associated wall

Studying Exotic Hadrons in Heavy Ion Collisions

We investigate the possibilities of using measurements in present and future experiments on heavy ion collisions to answer some longstanding problems in hadronic physics, namely identifying hadronic molecular states and exotic hadrons with multiquark components. The yields of a selected set of exotic hadron candidates in relativistic heavy ion collisions are discussed in the coalescence model in comparison with the statistical model. We find that the yield of a hadron is typically an order of magnitude smaller when it is a compact multiquark state, compared to that of an excited hadronic state with normal quark numbers. We also find that some loosely bound hadronic molecules are formed more abundantly than the statistical model prediction by a factor of two or more. Moreover, due to the significant numbers of charm and bottom quarks produced at RHIC and even larger numbers expected at LHC, some of the proposed heavy exotic hadrons could be produced with sufficient abundance for detection, making it possible to study these new exotic hadrons in heavy ion collisions.Comment: 18 pages, 2 figure

Berry phase, hyperorbits, and the Hofstadter spectrum: semiclassical dynamics in magnetic Bloch bands

We have derived a new set of semiclassical equations for electrons in magnetic Bloch bands. The velocity and energy of magnetic Bloch electrons are found to be modified by the Berry phase and magnetization. This semiclassical approach is used to study general electron transport in a DC or AC electric field. We also find a close connection between the cyclotron orbits in magnetic Bloch bands and the energy subbands in the Hofstadter spectrum. Based on this formalism, the pattern of band splitting, the distribution of Hall conduct- ivities, and the positions of energy subbands in the Hofstadter spectrum can be understood in a simple and unified picture.Comment: 26 pages, Revtex, 6 figures included, submitted to Phys.Rev.