Editorial: Controversies and solutions in environmental sciences: Addressing toxicity of sediments and soils

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2007 Ecomed Publishers

Effect of arm movement on balance performance in children: role of expertise in gymnastics

OBJECTIVE: Studies have shown that balance performance is better in gymnasts compared to age-/sex-matched controls and further studies revealed superior performance when arms were free to move during assessment of balance. However, it is unknown whether free arm movement during balance testing differentially affects balance performance with respect to sports expertise (i.e., gymnasts are less affected than age-/sex-matched controls). Therefore, we investigated the effect of arm movement on balance performance in young female gymnasts compared to age-/sex-matched controls while performing balance tasks with various difficulty levels. RESULTS: In both samples, balance performance (except for the timed one-legged stance) was significantly better during free compared to restricted arm movement conditions and this was especially observed in the highest task difficulty condition of the 3-m beam walking backward test. These findings revealed that balance performance is positively affected by free arm movements, but this does not seem to be additionally influenced by the achieved expertise level in young gymnasts

A BeppoSAX observation of the super-soft source CAL87

We report on a BeppoSAX Concentrator Spectrometer observation of the super-soft source (SSS) CAL87. The X-ray emission in SSS is believed to arise from nuclear burning of accreted material on the surface of a white dwarf (WD). An absorbed blackbody spectral model gives a chi^2_v of 1.18 and a temperature of 42 +/- ^13 _11 eV. However, the derived luminosity and radius are greater than the Eddington limit and radius of a WD. Including an O viii edge at 0.871 keV gives a significantly better fit (at > 95% confidence) and results in more realistic values of the source luminosity and radius. We also fit WD atmosphere models to the CAL87 spectrum. These also give reasonable bolometric luminosities and radii in the ranges 2.7-4.8 10^{36} erg/s and 8-20 10^7 cm, respectively. These results support the view that the X-ray emission from CAL87 results from nuclear burning in the atmosphere of a WD.Comment: 4 pages. Accepted for publication in A&A (Letters

Murine cytomegalovirus inhibits interferon γ-induced antigen presentation to CD4 T cells by macrophages via regulation of expression of major histocompatibility complex class II-associated genes

CD4 T cells and interferon γ (IFN-γ) are required for clearance of murine cytomegalovirus (MCMV) infection from the salivary gland in a process taking weeks to months. To explain the inefficiency of salivary gland clearance we hypothesized that MCMV interferes with IFN-γ induced antigen presentation to CD4 T cells. MCMV infection inhibited IFN-γ-induced presentation of major histocompatibility complex (MHC) class II associated peptide antigen by differentiated bone marrow macrophages (BMMΦs) to a T cell hybridoma via impairment of MHC class II cell surface expression. This effect was independent of IFN-α/β induction by MCMV infection, and required direct infection of the BMMΦs with live virus. Inhibition of MHC class II cell surface expression was associated with a six- to eighffold reduction in IFN-γ induced IAb mRNA levels, and comparable decreases in IFN-γ induced expression of invariant chain (Ii), H-2Ma, and H-2Mb mRNAs. Steady state levels of several constitutive host mRNAs, including β-actin, cyclophilin, and CD45 were not significantly decreased by MCMV infection, ruling out a general effect of MCMV infection on mRNA levels. MCMV effects were specific to certain MHC genes since IFN-γ-induced transporter associated with antigen presentation (TAP)2 mRNA levels were minimally altered in infected cells. Analysis of early upstream events in the IFN-γ signaling pathway revealed that MCMV did not affect activation and nuclear translocation of STAT1α, and had minor effects on the early induction of IRF-1 mRNA and protein. We conclude that MCMV infection interferes with IFN-γ-mediated induction of specific MHC genes and the Ii at a stage subsequent to STAT1α activation and nuclear translocation. This impairs antigen presentation to CD4 T cells, and may contribute to the capacity of MCMV to spread and persist within the infected host

Study of led lamp power supply

В данной статье исследуется источник питания светодиодного светильника с высокимкоэффициентом мощности. Использована микросхема корректора коэффициента мощности компании STMicroelectronics L6561 в обратноходовой топологии. С помощью этой микросхемы упрощается построение источника питания, учитывая стандарты энергосбережения и требования к уровню вносимых в питающую сеть искажений.In this article, we investigate the LED lamp power supply with a high power factor. To implement this, the power factor corrector of STMicroelectronics L6561 is used in the fly-back topology. With the help of this IC simplifies the construction of the power supply, considering energy-efficiency standards and requirements for the level introduced into the mains distortion.Fir filter design using frequency sampling method

Gravitational Wave Memory of Gamma-Ray Burst Jets

Gamma-Ray Bursts (GRBs) are now considered as relativistic jets. We analyze the gravitational waves from the acceleration stage of the GRB jets. We show that (i) the point mass approximation is not appropriate if the opening half-angle of the jet is larger than the inverse of the Lorentz factor of the jet, (ii) the gravitational waveform has many step function like jumps, and (iii) the practical DECIGO and BBO may detect such an event if the GRBs occur in Local group of galaxy. We found that the light curve of GRBs and the gravitational waveform are anti-correlated so that the detection of the gravitational wave is indispensable to determine the structure of GRB jets.Comment: Revtex4, 10 pages, 6 figures, Fig.2 and Fig.3 replaced, minor changes to text in Sec.I and Sec.V, typos corrected, some reference added, Version to be published in PR

Anaerobic starvation survival of marine bacteria

Starvation affects marine bacteria also under anaerobic conditions. Some basic data obtained for anaerobic starvation survival of a fermentative and a sulfaterespiring strain indicate substantial differences. The fermentative strain, Listonella (= Vibrio) anguillarum, responded to, nutrient depletion with rapid reduction of their cell size (dwarfing) and decline of viable cell counts by three orders of magnitude. The sulfate-respiring Desulfovibrio vulgaris showed only minor reductions of the cell sizes and no loss of viability. Whereas a drastic decline of cellular protein concentrations in this strain indicated strong endogeneous respiration, starved cells of the fermenting Vibrio sp. showed increasing levels of protein after an initial decrease

Дизайн наглядно-дидактического комплекта для реализации программ обучения в различных областях изобразительного искусства

Целью выпускной квалификационной работы является разработка дидактического комплекта для проведения морфологического анализа в изучении творческих дисциплин. В специализированных художественных учреждениях, учащиеся, анализируя натуру, придают большее значение срисовыванию, копированию, нежели соблюдение закономерностей построения формы предмета - эту проблему решает дидактический комплект. Разработанный дидактический комплект имеет уникальное решение и позволит решить поставленные задачи как данной ВКР, так и других проектов, в основе которых будет лежать проблема принципа формообразования.The goal of the final qualifying work is the development of a didactic kit for morphological analysis in the study of creative disciplines. In specialized art institutions, students, analyzing nature, attach greater importance to drawing, copying, rather than observing the laws of constructing the form of the object - this problem is solved by the didactic kit. The didactic kit developed has a unique solution and will allow to solve the tasks set for both this WRC and other projects based on the problem of the form-building principle

XTE J1739-302: An Unusual New X-ray Transient

A new x-ray transient, designated XTE J1739-302, was discovered with the Proportional Counter Array (PCA) on the Rossi X-ray Timing Explorer (RXTE) in data from 12 August 1997. Although it was the brightest source in the Galactic Center region while active (about 3.0 x 10^-9 ergs/cm2/s from 2 to 25 keV), it was only observed on that one day; it was not detectable nine days earlier or two days later. There is no known counterpart at other wavelengths, and its proximity to the Galactic Center will make such an identification difficult due to source confusion and extinction. The x-ray spectrum and intensity suggest a giant outburst of a Be/neutron star binary, although no pulsations were observed and the outburst was shorter than is usual from these systems.Comment: 11 pages incorporating 6 figures, AAStex; accepted for The Astrophysical Journal, Part 2 (Letters