On the Phase Boundaries of the Integer Quantum Hall Effect. II

It is shown that the statements about the observation of the transitions between the insulating phase and the integer quantum Hall effect phases with the quantized Hall conductivity $\sigma_{xy}^{q}$ $\geq 3e^{2}/h$ made in a number of works are unjustified. In these works, the crossing points of the magnetic field dependences of the diagonal resistivity at different temperatures at $\omega_{c}\tau \approx 1$ have been misidentified as the critical points of the phase transitions. In fact, these crossing points are due to the sign change of the derivative $d\rho_{xx}/dT$ owing to the quantum corrections to the conductivity.Comment: 3 pages, 2 figure

Quark Model and Neutral Strange Secondary Production by Neutrino and Antineutrino Beams

The experimental data on $K^0$ and $\Lambda$ production by $\nu$ and $\bar{\nu}$ beams are compared with the predictions of quark model assuming that the direct production of secondaries dominates. Disagreement of these predictions with the data allows one to suppose that there exists considerable resonance decay contribution to the multiplicities of produced secondaries.Comment: 6 pages, no figures, 2 table

Topological oscillations of the magnetoconductance in disordered GaAs layers

Oscillatory variations of the diagonal ($G_{xx}$) and Hall ($G_{xy}$) magnetoconductances are discussed in view of topological scaling effects giving rise to the quantum Hall effect. They occur in a field range without oscillations of the density of states due to Landau quantization, and are, therefore, totally different from the Shubnikov-de Haas oscillations. Such oscillations are experimentally observed in disordered GaAs layers in the extreme quantum limit of applied magnetic field with a good description by the unified scaling theory of the integer and fractional quantum Hall effect.Comment: 4 pages, 4 figure

Spin-splitting in the quantum Hall effect of disordered GaAs layers with strong overlap of the spin subbands

With minima in the diagonal conductance G_{xx} and in the absolute value of the derivative |dG_{xy}/dB| at the Hall conductance value G_{xy}=e^{2}/h, spin-splitting is observed in the quantum Hall effect of heavily Si-doped GaAs layers with low electron mobility 2000 cm^2/Vs in spite of the fact that the spin-splitting is much smaller than the level broadening. Experimental results can be explained in the frame of the scaling theory of the quantum Hall effect, applied independently to each of the two spin subbands.Comment: 4 pages, 4 figure

Two Pfam protein families characterized by a crystal structure of protein lpg2210 from Legionella pneumophila.

BackgroundEvery genome contains a large number of uncharacterized proteins that may encode entirely novel biological systems. Many of these uncharacterized proteins fall into related sequence families. By applying sequence and structural analysis we hope to provide insight into novel biology.ResultsWe analyze a previously uncharacterized Pfam protein family called DUF4424 [Pfam:PF14415]. The recently solved three-dimensional structure of the protein lpg2210 from Legionella pneumophila provides the first structural information pertaining to this family. This protein additionally includes the first representative structure of another Pfam family called the YARHG domain [Pfam:PF13308]. The Pfam family DUF4424 adopts a 19-stranded beta-sandwich fold that shows similarity to the N-terminal domain of leukotriene A-4 hydrolase. The YARHG domain forms an all-helical domain at the C-terminus. Structure analysis allows us to recognize distant similarities between the DUF4424 domain and individual domains of M1 aminopeptidases and tricorn proteases, which form massive proteasome-like capsids in both archaea and bacteria.ConclusionsBased on our analyses we hypothesize that the DUF4424 domain may have a role in forming large, multi-component enzyme complexes. We suggest that the YARGH domain may play a role in binding a moiety in proximity with peptidoglycan, such as a hydrophobic outer membrane lipid or lipopolysaccharide

Fractional quantum Hall effect without energy gap

In the fractional quantum Hall effect regime we measure diagonal ($\rho_{xx}$) and Hall ($\rho_{xy}$) magnetoresistivity tensor components of two-dimensional electron system (2DES) in gated GaAs/Al$_{x}$Ga$_{1-x}$As heterojunctions, together with capacitance between 2DES and the gate. We observe 1/3- and 2/3-fractional quantum Hall effect at rather low magnetic fields where corresponding fractional minima in the thermodynamical density of states have already disappeared manifesting complete suppression of the quasiparticle energy gaps.Comment: 4 pages, 4 figure

Environmental risk to health of the population

Researches of the last years in the field of ecological epidemiology and the analysis of risk for health allow to claim with confidence that the polluted environment is one of the important factors defining changes of a state of health of the population. Expert opinions on the scale of this influence differ considerably now. These estimations vary from small shares of percent to several percent, reaching in some cases 30-50%. An attempt to elaborate economic approaches to a risk assessment to health of the population has been made in this work. The main reason which demands development of special approaches for an assessment of an environmental risk is that quantitative estimation of risk for health from environmental pollution is difficult to be realized. As a rule, population is affected by the whole set of the polluting substances from the atmosphere, drinking water, food, etc. For effective risk management it is necessary to assess and compare diverse risks caused by action of various pollutants coming to an organism in different ways. The stated methodical materials give an idea of possibility of the stage-by-stage multilevel risk analysis at the solution of environmental problems. Further comparative analysis connected with definition and comparison of various dangers can be done by means of the results received at a risk evaluation stage. © 2016 Anopchenko et al

Activated biochars as sustainable and effective supports for hydrogenations

Activated biochars were obtained from pyrolysis and CO2-physical activation of four different biomasses including tannery shaving waste (T), vine wood waste (W), barley waste (B) and Sargassum, brown macroalgae of Venice lagoon (A). The potential of obtained carbonaceous materials as the supports of Ni,Al catalysts was investigated in levulinic acid (LA) conversion to γ-valerolactone (GVL) as a model hydrogenation reaction. Al-containing species as the Lewis acid sites for the dehydration step were incorporated to the supports using wet impregnation or precipitation. Ni as a hydrogenation active phase was added to the supports via wet impregnation. Biochar-based supports and catalysts were characterized by AAS, elemental analysis, FTIR, N2 physisorption, XRD, SEM, EDS, TEM, He-TPD, NH3-TPD and TPR techniques. The catalysts were tested for LA hydrogenation to GVL in a batch system and aqueous medium. The results showed that Ni supported on activated biochar was not active due to a lack of Lewis acid sites for dehydration. Precipitated Al-containing species on the biochar-based supports demonstrated a better catalytic performance in the reaction compared to impregnated one because of different interactions with the support and Ni species. Among different supports, the activated biochars obtained from T and W acted as the best ones. A higher catalytic efficiency was strongly influenced by the chemical (aromaticity and stability, presence of N,O-doped and functional groups), textural (the porous texture and surface area), and morphological (higher dispersion of active phases) properties of activated biochars obtained from different biomasses with different natures