Muon-spin-rotation study of the magnetic structure in the tetragonal antiferromagnetic state of weakly underdoped Ba1−x _{1-x} Kx _{x} Fe2 _{2} As2 _{2}

With muon spin rotation ($\mu$SR) we studied the transition between the orthorhombic antiferromagnetic (o-AF) and the tetragonal antiferromagnetic (t-AF) states of a weakly underdoped Ba$_{1-x}$K$_{x}$Fe$_{2}$As$_{2}$ single crystal. We observed some characteristic changes of the magnitude and the orientation of the magnetic field at the muon site which, due to the fairly high point symmetry of the latter, allow us to identify the magnetic structure of the t-AF state. It is the so-called, inhomogeneous double-$\mathbf{Q}$ magnetic structure with $c$-axis oriented moments which has a vanishing magnetic moment on half of the Fe sites.Comment: 5 pages, 4 figures. Supplementary Material: 8 figure

Partially ionized plasmas in electromagnetic fields

The interaction of partially ionized plasmas with an electromagnetic field is investigated using quantum statistical methods. A general statistical expression for the current density of a plasma in an electromagnetic field is presented and considered in the high field regime. Expressions for the collisional absorption are derived and discussed. Further, partially ionized plasmas are considered. Plasma Bloch equations for the description of bound-free transitions are given and the absorption coefficient as well as rate coefficients for multiphoton ionization are derived and numerical results are presented.Comment: 18 pages, 8 figures, accepted for publication in J. Phys.: Conf. Se

Lean implementations of software testing tools using XML representations of source codes

By utilizing XML representations of source programs under test, a new approach is proposed to concisely implement some prototypes for TACCLE, a software testing methodology. The conversions between a source program and its XML representation can be easily realized using existing conversion tools. In this way, the conversion tools can automatically analyze and parse the source program, so that testing tool developers only need to concentrate on the manipulation of the XML document. If appropriate XML DOM APIs are chosen, the implementations of such testing tools will be pretty lean. A detailed case study for GMPS tool, a prototype for the TACCLE methodology, is presented to illustrate the new approach. © 2008 IEEE.published_or_final_versionThis research is supported by the Jinan University Youth Foundation under Grant #51208035, Union Grant of Guangdong Province and National Natural Science Foundation of China under Grant #U0775001, and the Guangdong Province Science Foundation under Grant #7010116

Proportional sampling strategy: A compendium and some insights

There have been numerous studies on the effectiveness of partition and random testing. In particular, the proportional sampling (PS) strategy has been proved, under certain conditions, to be the only form of partition testing that outperforms random testing regardless of where the failure-causing inputs are. This paper provides an integrated synthesis and overview of our recent studies on the PS strategy and its related work. Through this synthesis, we offer a perspective that properly interprets the results obtained so far, and present some of the interesting issues involved and new insights obtained during the course of this research. © 2001 Elsevier Science Inc. All rights reserved.postprin

On the methanol emission detection in the TW Hya disc: the role of grain surface chemistry and non-LTE excitation

The recent detection of gas-phase methanol (CH$_3$OH) lines in the disc of TW Hya by Walsh et al. provided the first observational constraints on the complex O-bearing organic content in protoplanetary discs. The emission has a ring-like morphology, with a peak at $\sim 30-50$ au and an inferred column density of $\sim 3-6\times10^{12}$ cm$^{-2}$. A low CH$_3$OH fractional abundance of $\sim 0.3-4\times 10^{-11}$ (with respect to H$_2$) is derived, depending on the assumed vertical location of the CH$_3$OH molecular layer. In this study, we use a thermo-chemical model of the TW Hya disc, coupled with the ALCHEMIC gas-grain chemical model, assuming laboratory-motivated, fast diffusivities of the surface molecules to interpret the CH$_3$OH detection. Based on this disc model, we performed radiative transfer calculations with the LIME code and simulations of the observations with the CASA simulator. We found that our model allows to reproduce the observations well. The CH$_3$OH emission in our model appears as a ring with radius of $\sim60$ au. Synthetic and observed line flux densities are equal within the rms noise level of observations. The synthetic CH$_3$OH spectra calculated assuming local thermodynamic equilibrium (LTE) can differ by up to a factor of 3.5 from the non-LTE spectra. For the strongest lines, the differences between LTE and non-LTE flux densities are very small and practically negligible. Variations in the diffusivity of the surface molecules can lead to variations of the CH$_3$OH abundance and, therefore, line flux densities by an order of magnitude.Comment: Accepted for publication in MNRAS, 8 pages, 8 figure

Liver Cirrhosis As a Real Risk Factor for Necrotising Fasciitis: a Three-Year Population‑Based Follow‑Up Study

[[abstract]]INTRODUCTION Necrotising fasciitis (NF) is often found in patients with diabetes mellitus, chronic renal failure, alcoholism, malignancy or liver cirrhosis. However, it remains unknown whether liver cirrhosis is an independent risk factor for the occurrence of NF. This study aimed to determine whether liver cirrhosis is an independent risk factor for the occurrence of NF, and to identify the relationship between severity of liver cirrhosis and occurrence of NF. METHODS The National Health Insurance Research Database, maintained by Taiwan’s National Health Insurance programme, was retrospectively analysed, and the hospitalisation data of 40,802 cirrhotic patients and 40,865 randomly selected, age‑ and gender‑matched non‑cirrhotic control patients was collected. The medical records of all patients were individually followed for a three‑year period from the patients’ first hospitalisation in 2004. RESULTS During the three‑year follow‑up period, there were 299 (0.7%) cirrhotic patients with NF and 160 (0.4%) non‑cirrhotic patients with NF. Cox regression analysis showed that liver cirrhosis was a risk factor for the occurrence of NF during the study period (hazard ratio 1.982; p < 0.001). Among cirrhotic patients, those with complicated liver cirrhosis had a higher risk for the occurrence of NF than patients with non‑complicated liver cirrhosis (hazard ratio 1.320; p = 0.028). CONCLUSION Cirrhotic patients had a higher risk for the occurrence of NF than non‑cirrhotic patients, and the risk for NF was especially high among patients with complicated liver cirrhosis.[[notice]]補正完畢[[journaltype]]國外[[incitationindex]]SCI[[booktype]]紙本[[countrycodes]]SG