264 research outputs found
Detection of an intergalactic meteor particle with the 6-m telescope
On July 28, 2006 the 6-m telescope of the Special Astrophysical Observatory
of the Russian Academy of Sciences recorded the spectrum of a faint meteor. We
confidently identify the lines of FeI and MgI, OI, NI and molecular-nitrogen
N_2 bands. The entry velocity of the meteor body into the Earth's atmosphere
estimated from radial velocity is equal to 300 km/s. The body was several tens
of a millimeter in size, like chondrules in carbon chondrites. The radiant of
the meteor trajectory coincides with the sky position of the apex of the motion
of the Solar system toward the centroid of the Local Group of galaxies.
Observations of faint sporadic meteors with FAVOR TV CCD camera confirmed the
radiant at a higher than 96% confidence level. We conclude that this meteor
particle is likely to be of extragalactic origin. The following important
questions remain open: (1) How metal-rich dust particles came to be in the
extragalactic space? (2) Why are the sizes of extragalactic particles larger by
two orders of magnitude (and their masses greater by six orders of magnitude)
than common interstellar dust grains in our Galaxy? (3) If extragalactic dust
surrounds galaxies in the form of dust (or gas-and-dust) aureoles, can such
formations now be observed using other observational techniques (IR
observations aboard Spitzer satellite, etc.)? (4) If inhomogeneous
extragalactic dust medium with the parameters mentioned above actually exists,
does it show up in the form of irregularities on the cosmic microwave
background (WMAP etc.)?Comment: 9 pages, 6 EPS figure
Modulational instability of bright solitary waves in incoherently coupled nonlinear Schr\"odinger equations
We present a detailed analysis of the modulational instability (MI) of
ground-state bright solitary solutions of two incoherently coupled nonlinear
Schr\"odinger equations. Varying the relative strength of cross-phase and
self-phase effects we show existence and origin of four branches of MI of the
two-wave solitary solutions. We give a physical interpretation of our results
in terms of the group velocity dispersion (GVD) induced polarization dynamics
of spatial solitary waves. In particular, we show that in media with normal GVD
spatial symmetry breaking changes to polarization symmetry breaking when the
relative strength of the cross-phase modulation exceeds a certain threshold
value. The analytical and numerical stability analyses are fully supported by
an extensive series of numerical simulations of the full model.Comment: Physical Review E, July, 199
Analysis of Epidemiological Situation on Leptospiroses in the Amur-River Region. Operational Experience in the Flood Area in 2013, and Forecasting for 2014
For the first time ever mobile SAET units have performed complex investigation of epidemiological situation on leptospiroses in order to provide sanitary-epidemiological welfare of the population in the Amur-River region devastated by high water in 2013. Analyzed have been contemporary published and archival data on morbidity rate and epizootic activity of the natural leptospirosis foci in the Amur-River territory up to 2013. Summarized is the information concerning monitoring over natural focal infections (in particular leptospiroses) in the flooding area, obtained by specialized antiepidemic teams from Irkutsk Research Anti-Plague Institute of Siberia and Far East deployed in Belogorsk town of the Amur Region and Khabarovsk city in 2013. Epizootiological situation during the high water period in the Jewish Autonomous Region has been defined as an extremely adverse, unlike the Khabarovsk Territory and the Amur Region where epizootic process is less expressed. Therewith aggravation of epidemiological situation on leptospiroses in the Amur-River Region in 2014 is not ruled out
Analysis of Epidemiological Situation on Hemorrhagic Fever with Renal Syndrome in the Khabarovsk Territory and the Jewish Autonomous Region, and Prognosis of Its Development for the Past-Flood Period in 2013-2014
Complex analysis of the data concerning epidemiological situation on HFRS in the Khabarovsk Territory and the Jewish Autonomous Region for the past decade (2003-2012) previous to high water in 2013 and results of operative epidemiological inspection of the flooding area and the adjoining territory where a high index of laboratory evidences of the virus presence in the main carriers was revealed, outlines high probability of the epidemiological condition complications in view of the infection in the post-flooding period in 2013-2014 in the both entities. Therewith on the basis of the unfavorable prognosis for the epidemiological situation development a Plan of organizational, preventive and anti-epidemic measures directed to minimization of risks related to aggravation of epidemiological situation on hemorrhagic fever with renal syndrome has been developed and is being implemented
Reactivity of Metal-Free and Metal-Associated Amyloid-?? with Glycosylated Polyphenols and Their Esterified Derivatives
Both amyloid-?? (A??) and transition metal ions are shown to be involved in the pathogenesis of Alzheimer???s disease (AD), though the importance of their interactions remains unclear. Multifunctional molecules, which can target metal-free and metal-bound A?? and modulate their reactivity (e.g., A?? aggregation), have been developed as chemical tools to investigate their function in AD pathology; however, these compounds generally lack specificity or have undesirable chemical and biological properties, reducing their functionality. We have evaluated whether multiple polyphenolic glycosides and their esterified derivatives can serve as specific, multifunctional probes to better understand AD. The ability of these compounds to interact with metal ions and metal-free/-associated A??, and further control both metal-free and metal-induced A?? aggregation was investigated through gel electrophoresis with Western blotting, transmission electron microscopy, UV-Vis spectroscopy, fluorescence spectroscopy, and NMR spectroscopy. We also examined the cytotoxicity of the compounds and their ability to mitigate the toxicity induced by both metal-free and metal-bound A??. Of the polyphenols investigated, the natural product (Verbascoside) and its esterified derivative (VPP) regulate the aggregation and cytotoxicity of metal-free and/or metal-associated A?? to different extents. Our studies indicate Verbascoside represents a promising structure for further multifunctional tool development against both metal-free A?? and metal-A??.open0
Epizootiological-and-Epidemical Situation on Tularemia in the South of Far East Region during the Period of River Floods
Carried out were epizootiological studies of the flooded areas of the Amur Region, the Khabarovsk territory, and the Jewish autonomous region in order to investigate the situation on tularemia in view of the river floods in August-September, 2013. Involved were specialized anti-epidemic teams from Irkutsk Research Anti-Plague Institute for works at the site of emergency. Therewith, analysis of the data of the epizootiological examination of the territories obtained in cooperation with specialists from the Rospotrebnadzor local Centers of Hygiene and Epidemiology, and results of laboratory investigations with application of bacteriological, immuÂnoÂbioÂlogical and molecular-genetic methods indicated insignificant epizootic and epidemic activity of the natural tularemia foci. Given is the conclusion on epizootiological-epidemiological condition for tularemia in the flooded areas of the Amur River region and a short-term epizootiological forecast for 2013-2014, as well as recommendations concerning stabilization and improvement of epidemiological conditions in the region
Getting âSmad' about obesity and diabetes
Recent findings on the role of transforming growth factor (TGF)-β/Smad3 signaling in the pathogenesis of obesity and type 2 diabetes have underscored its importance in metabolism and adiposity. Indeed, elevated TGF-β has been previously reported in human adipose tissue during morbid obesity and diabetic neuropathy. In this review, we discuss the pleiotropic effects of TGF-β/Smad3 signaling on metabolism and energy homeostasis, all of which has an important part in the etiology and progression of obesity-linked diabetes; these include adipocyte differentiation, white to brown fat phenotypic transition, glucose and lipid metabolism, pancreatic function, insulin signaling, adipocytokine secretion, inflammation and reactive oxygen species production. We summarize the recent in vivo findings on the role of TGF-β/Smad3 signaling in metabolism based on the studies using Smad3â/â mice. Based on the presence of a dual regulatory effect of Smad3 on peroxisome proliferator-activated receptor (PPAR)β/δ and PPARÎł2 promoters, we propose a unifying mechanism by which this signaling pathway contributes to obesity and its associated diabetes. We also discuss how the inhibition of this signaling pathway has been implicated in the amelioration of many facets of metabolic syndromes, thereby offering novel therapeutic avenues for these metabolic conditions
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