Confinement induced by fermion damping in three-dimensional QED

The three-dimensional non-compact QED is known to exhibit weak confinement when fermions acquire a finite mass via the mechanism of dynamical chiral symmetry breaking. In this paper, we study the effect of fermion damping caused by elastic scattering on the classical potential between fermions. By calculating the vacuum polarization function that incorporates the fermion damping effect, we show that fermion damping can induce a weak confinement even when the fermions are massless and the chiral symmetry is not broken.Comment: 4 pages, no figur

Field-effect mobility enhanced by tuning the Fermi level into the band gap of Bi2Se3

By eliminating normal fabrication processes, we preserve the bulk insulating state of calcium-doped Bi2Se3 single crystals in suspended nanodevices, as indicated by the activated temperature dependence of the resistivity at low temperatures. We perform low-energy electron beam irradiation (<16 keV) and electrostatic gating to control the carrier density and therefore the Fermi level position in the nanodevices. In slightly p-doped Bi2-xCaxSe3 devices, continuous tuning of the Fermi level from the bulk valence band to the band-gap reveals dramatic enhancement (> a factor of 10) in the field-effect mobility, which suggests suppressed backscattering expected for the Dirac fermion surface states in the gap of topological insulators

A 4-Layer Method of Developing Integrated Sensor Systems With Lab VIEW

System integrity is important for fast and accurate measurement and control. LabVIEW is widely used in education and industry. Many LabVIEW codes are hard to be read and shown because of their 2D topology. In order to simplify the programming, a 4-layer model of developing sensor or measurement systems with LabVIEW is proposed in this paper. The purpose of this paper is to show the readers how to design simple, clear and strong automated systems with LabVIEW. Using a Sensirion SHT75 humidity sensor and an NI USB6008 DAQ board as an example, this paper describes the steps of developing a sensor system from the physical layer to application layer in detail. In layer 2, port selection and signal regulation are demonstrated. In layer 3, timing waveform analysis and synthesis, state diagram analysis, instruction set design, micro operation and fault tolerance designs are demonstrated. In layer 4, data visualization is covered with a vivid example. Programmers found it was hard to show readers their LabVIEW codes because many LabVIEW codes occupy several screens. A layer model simplifies the programming, so one is able to show a medium size LabVIEW code easily

Effect of dietary conjugated linoleic acid (CLA) on the growth and lipid metabolism of geese and fatty acid composition of their tissues

The objective of this study was to determine the effects of conjugated linoleic acid (CLA) oil supplementation on the growth performance and lipid metabolism in geese and the fatty acid concentrations in their liver and muscle tissues. One hundred and ninety two one-day old geese were randomly assigned to one of four dietary treatments. The diet in Group A, the control, contained 2.5% soyabean oil, that in Group B 2.0% soyabean oil and 0.5% CLA, that in Group C 1.0% soybean oil and 1.5% CLA and that in Group D 2.5% CLA. The birds were fed for 56 days. No significant effects were observed in body weight and body weight gain between Groups B, C and the control, but these parameters were significantly lower in Group D compared to the control. The feed intake, feed conversion ratio (FCR) and abdominal fat percentage (AFP) were significantly lower in the groups receiving CLA in their diets compared with the control. Dietary CLA altered serum lipid concentrations by decreasing total cholesterol, triglyceride and low density lipoprotein-cholesterol concentrations, the atherogenic index and activity of lipoprotein lipase, and increased serum concentration of high density lipoprotein-cholesterol. The fatty acid composition of the liver and muscle tissues showed significant increases in the biologically active cis-9, trans-11 and trans-10, cis-12 CLA isomers in the geese fed increasing levels of CLA. The supplementation of CLA to the geese led to significant increases in saturated fatty acid concentrations and significant reductions in the monounsaturated fatty acid concentrations in liver and muscle tissues. The results clearly demonstrated that geese can successfully incorporate CLA in their liver and muscle tissues, thus producing a healthy food for humans. Keywords: Conjugated linoleic acid, geese, growth, lipid metabolism, fatty acid compositionSouth African Journal of Animal Science Vol. 38 (1) 2008: pp. 12-2