Exact solutions in Einstein-Yang-Mills-Dirac systems

We present exact solutions in Einstein-Yang-Mills-Dirac theories with gauge groups SU(2) and SU(4) in Robertson-Walker space-time $R \times S^3$, which are symmetric under the action of the group SO(4) of spatial rotations. Our approach is based on the dimensional reduction method for gauge and gravitational fields and relates symmetric solutions in EYMD theory to certain solutions of an effective dynamical system. We interpret our solutions as cosmological solutions with an oscillating Yang-Mills field passing between topologically distinct vacua. The explicit form of the solution for spinor field shows that its energy changes the sign during the evolution of the Yang-Mills field from one vacuum to the other, which can be considered as production or annihilation of fermions. Among the obtained solutions there is also a static sphaleron-like solution, which is a cosmological analogue of the first Bartnik-McKinnon solution in the presence of fermions.Comment: 18 pages, LaTeX 2

New Anisotropic Behavior of Quantum Hall Resistance in (110) GaAs Heterostructures at mK Temperatures and Fractional Filling Factors

Transport experiments in high mobility (110) GaAs heterostructures have been performed at very low temperatures 8 mK. At higher Landau-Levels we observe a transport anisotropy that bears some similarity with what is already seen at half-odd-integer filling on (001) oriented substrates. In addition we report the first observation of transport anisotropies within the lowest Landau-Level. This remarkable new anisotropy is independent of the current direction and depends on the polarity of the magnetic field.Comment: 3 Pages, 4 figures, Latex, uses elsart.cls and physart.cls, to be published in Physica E Added reference, made contact configuration more clea

The effect of anatomic differences on the relationship between renal artery and diaphragmatic crus

Background: The aim of this study is to investigate the effect of anatomic differences on the relationship between renal artery and diaphragmatic crus via the touch of two structures. Materials and methods: The study included dynamic computed tomography (CT) scans of 308 patients performed mainly for characterisation of liver and renal masses. Anatomic differences including the thickness of the diaphragmatic crus, the localisation of renal artery ostium at the wall of aorta, the level of renal artery origin with respect to superior mesenteric artery were evaluated. Statistical relationships between renal artery-diaphragmatic crus contact and the anatomic differences were assessed. Results: Thickness of the diaphragmatic crus at the level of renal artery origin exhibited a statistically significant relationship to renal artery-diaphragmatic crus contact at the left (p < 0.001) and right side (p < 0.001). There was a statistically significant relationship between high renal artery origin and renal artery- -diaphragmatic crus contact at the left (p < 0.001) and right side (p = 0.01). The localisation of renal artery ostium at the wall of aorta (right side, p = 0.436, left side, p = 0.681) did not demonstrate a relationship to renal artery-diaphragmatic crus contact. Conclusions: Thickness of the diaphragmatic crus and high renal artery origin with respect to superior mesenteric artery are crucial anatomic differences determining the relationship of renal artery and diaphragmatic crus. (Folia Morphol 2018; 77, 1: 22–28)

Unconventional MBE Strategies from Computer Simulations for Optimized Growth Conditions

We investigate the influence of step edge diffusion (SED) and desorption on Molecular Beam Epitaxy (MBE) using kinetic Monte-Carlo simulations of the solid-on-solid (SOS) model. Based on these investigations we propose two strategies to optimize MBE growth. The strategies are applicable in different growth regimes: During layer-by-layer growth one can exploit the presence of desorption in order to achieve smooth surfaces. By additional short high flux pulses of particles one can increase the growth rate and assist layer-by-layer growth. If, however, mounds are formed (non-layer-by-layer growth) the SED can be used to control size and shape of the three-dimensional structures. By controlled reduction of the flux with time we achieve a fast coarsening together with smooth step edges.Comment: 19 pages, 7 figures, submitted to Phys. Rev.

Insulin-Like Growth Factor I Does Not Drive New Bone Formation in Experimental Arthritis

Insulin like growth factor (IGF)-I can act on a variety of cells involved in cartilage and bone repair, yet IGF-I has not been studied extensively in the context of inflammatory arthritis. The objective of this study was to investigate whether IGF-I overexpression in the osteoblast lineage could lead to increased reparative or pathological bone formation in rheumatoid arthritis and/or spondyloarthritis respectively.status: publishe

Infrared Properties of QCD from Dyson-Schwinger equations

I review recent results on the infrared properties of QCD from Dyson-Schwinger equations. The topics include infrared exponents of one-particle irreducible Green's functions, the fixed point behaviour of the running coupling at zero momentum, the pattern of dynamical quark mass generation and properties of light mesons.Comment: 47 pages, 19 figures, Topical Review to be published in J.Phys.G, v2: typos corrected and some references adde

Is less more? Lessons from aptamer selection strategies

Aptamers have many inherent advantages originating from their in vitro selection and tailored chemical synthesis that makes them appealing alternatives of antibodies in bioaffinity assays. However, what ultimately matters, and that is the prerequisite to give way to all these advantages, is how well, and how selectively the aptamers bind to their targets. With the aptamer selection largely in the hand of life scientists, analytical chemists focused mostly on methodological development of aptamer-based assays using a fairly restricted number of aptamers to prove their concepts. However, ideally the development of an aptamer-based assay should start from the selection of aptamers to ensure their proper functionality in real samples. For instance information on the sample matrix can be implemented within counter-selection steps to discard aptamer candidates that show cross-reactivity to matrix components or critical interferents. In general, a larger consideration of the analytical use during selection and characterization of aptamers have been shown to increase the applicability of aptamers. Therefore, this review is a short, subjective view on trends in aptamer development highlighting factors to consider during their selection for a successful analytical application