Electrical conductivity of plasmas of DB white dwarf atmospheres

The static electrical conductivity of non-ideal, dense, partially ionized helium plasma was calculated over a wide range of plasma parameters: temperatures $1\cdot 10^{4}\textrm{K} \lesssim T \lesssim 1\cdot 10^{5}\textrm{K}$ and mass density $1 \times 10^{-6} \textrm{g}/\textrm{cm}^{3} \lesssim \rho \lesssim 2 \textrm{g}/\textrm{cm}^{3}$. Calculations of electrical conductivity of plasma for the considered range of plasma parameters are of interest for DB white dwarf atmospheres with effective temperatures $1\cdot 10^{4}\textrm{K} \lesssim T_{eff} \lesssim 3\cdot 10^{4}\textrm{K}$. Electrical conductivity of plasma was calculated by using the modified random phase approximation and semiclassical method, adapted for the case of dense, partially ionized plasma. The results were compared with the unique existing experimental data, including the results related to the region of dense plasmas. In spite of low accuracy of the experimental data, the existing agreement with them indicates that results obtained in this paper are correct

Phase Transition in Strongly Degenerate Hydrogen Plasma

Direct fermionic path-integral Monte-Carlo simulations of strongly coupled hydrogen are presented. Our results show evidence for the hypothetical plasma phase transition. Its most remarkable manifestation is the appearance of metallic droplets which are predicted to be crucial for the electrical conductivity allowing to explain the rapid increase observed in recent shock compression measurments.Comment: 1 LaTeX file using jetpl.cls (included), 5 ps figures. Manuscript submitted to JETP Letter

Path Integral Monte Carlo and Density Functional Molecular Dynamics Simulations of Hot, Dense Helium

Two first-principles simulation techniques, path integral Monte Carlo (PIMC) and density functional molecular dynamics (DFT-MD), are applied to study hot, dense helium in the density-temperature range of 0.387 - 5.35 g/cc and 500 K - 1.28x10^8 K. One coherent equation of state (EOS) is derived by combining DFT-MD data at lower temperatures with PIMC results at higher temperatures. Good agreement between both techniques is found in an intermediate temperature range. For the highest temperatures, the PIMC results converge to the Debye-Hueckel limiting law. In order derive the entropy, a thermodynamically consistent free energy fit is introduced that reproduces the internal energies and pressure derived from the first-principles simulations. The equation of state is presented in form of a table as well as a fit and is compared with chemical models. In addition, the structure of the fluid is analyzed using pair correlation functions. Shock Hugoniot curves are compared with recent laser shock wave experiments.Comment: 16 pages, 15 figure

Peculiarities of directions and causal agents’ distribution of tick-borne encephalitis in the Republic of Moldova

The aim of the study is to determine the circulation of tick-borne encephalitis (TBE) causal agents in the Ixodidae ticks population and the evaluation of the TBE threat to public health. The species of ticks Ixodes ricinus, Dermacentor reticulatus, D. marginatus and Haemaphysalis punctata can be often met in the ecosystems of the Republic of Moldova. The species I. ricinus is the most numerous and widespread one, the fact that shows its high epidemiological significance. At the same time the species D. reticulatus, D. marginatus and H. punctata are the potential directions of TBE maintaining the TBE viruses in the environment. The laboratory results got by the enzyme-linked immunosorbent assay (ELISA) have indicated the TBE virus antigen in of 25.2% of the ticks, collected in the period of 2009-2012. Using the polymerase chain reaction method it has been established that on average the RNA of TBE virus has been 8.1% of all tested tick samples. The specific antibodies to tick-borne encephalitis virus have been identified in 9 (4%) tested human specimens. The rationalization of the system of epidemiological surveillance and control of tick-born encephalitis consists in developing and implementing a definition of the case for report on the basis of clinical and laboratory criteria, as well as the communication with epidemiological station, and studying to obtain standardized and comparable data

Experimental infection of H5N1 HPAI in BALB/c mice

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Dense plasmas in astrophysics: from giant planets to neutron stars

We briefly examine the properties of dense plasmas characteristic of the interior of giant planets and the atmospheres of neutron stars. Special attention is devoted to the equation of state of hydrogen and helium at high density and to the effect of magnetic fields on the properties of dense matter.Comment: Invited Review, Strongly Coupled Coulomb Systems, Moscow June 2005; to appear in Journal of Physics

Tick-Borne Encephalitis with Hemorrhagic Syndrome, Novosibirsk Region, Russia, 1999

Eight fatal cases of tick-borne encephalitis with unusual hemorrhagic syndrome were identified in 1999 in the Novosibirsk Region, Russia. To study these strains, we sequenced cDNA fragments of protein E gene from six archival formalin-fixed brain samples. Phylogenetic analysis showed tick-borne encephalitis variants clustered with a Far Eastern subtype (homology 94.7%) but not with the Siberian subtype (82%)

МОЛЕКУЛЯРНО-ЭПИДЕМИОЛОГИЧЕСКОЕ РАССЛЕДОВАНИЕ ВСПЫШКИ СЕРОЗНЫХ МЕНИНГИТОВ В НОВОСИБИРСКОЙ ОБЛАСТИ

The aim of this study was to investigate the outbreak of aseptic meningitis in theNovosibirskregion in 2008–2009. We studied genetic diversity and molecular-epidemiological characteristics of human enteroviruses that caused aseptic meningitis. Materials and metods. In the present study we investigated samples of cerebrospinal fluid from 199 patients with a diagnosis “aseptic meningitis”, based on the clinical characteristics of the disease (headache, stiff neck, fever, nausea, vomiting), and confirmed by laboratory tests of spinal fluid (lymphocyte cell count > 10 cells/ml).All samples were tested by PCR for RNA of Enterovirus and Flavivirus and DNA Myc. tuberculosis, Borrelia spp., Neisseria spp. In the samples there were not found RNA Flavivirus, DNA Myc. tuberculosis, Borrelia spp., Neisseria spp., but in 73 samples (37%) was identified RNA enterovirus (EV). Determination of nucleotide sequences of 5’UTR and VP1-region of EV revealed that they belong to the following genotypes: the highest percentage was presented by genotype ECHO 30 (62%); another genotypes were Cox A2 (8%), Cox A4 (5%), Cox A14 (3%), Cox A16 (5%), Cox B5 (8%), ECHO 6 (3%), ECHO 9 (3% ) and ECHO 25 (3%). In 2008 most of the EV that caused the symptoms of aseptic meningitis belonged to genotype ECHO 30 (76%). In 2009 the clinical specimens containing genotype ECHO 30 were not found, but the largest percentage of EV belonged to genotypes Cox A2 (33%) and Cox A4 (22%). Thus, in 2008 we recorded outbreak of aseptic meningitis, the major etiological factor was enterovirus ECHO 30. And the rise of the incidence of aseptic meningitis in 2009 is related to the circulation of new genotypes of EV. The investigated strains were deposited in an international database GenBank under accession numbers KP258231-KP258235, HM559584.Целью настоящей работы явилось расследование вспышки серозных менингитов в Новосибирской области в 2008–2009 гг., а также изучение генетического разнообразия и молекулярно-эпидемиологиче- ской характеристики энтеровирусов человека, вызвавших случаи серозного менингита. Материал и методы. В настоящей работе исследованы образцы спинномозговой жидкости от 199 па- циентов с диагнозом «серозный менингит», основанным на клинической картине заболевания (головная боль, ригидность затылочных мышц, температура, тошнота, рвота) и подтвержденным лабораторными исследованиями спинномозговой жидкости (лимфоцитарный цитоз >10 кл/мкл). Все образцы иссле- дованы методом ПЦР на наличие РНК Enterovirus и Flavivirus, ДНК Myc. tuberculosis, Borrelia spp., Neisseria spp. В результате исследования проб отмечено отсутствие РНК Flavivirus, ДНК Myc. tuberculosis, Borrelia spp., Neisseria spp., однако в 73 образцах (в 37% случаев) была выявлена РНК энтеровирусов (ЭВ). Опре- деление нуклеотидных последовательностей ЭВ по регионам 5’UTR и VP1 выявило их принадлежность к следующим генотипам: наибольшая доля была представлена генотипом ECHO 30 (62 %); также встреча- лись Cox A2 (8%), Cox A4 (5%), Cox A14 (3%), Cox A16 (5%), Cox B5 (8%), ECHO 6 (3%), ECHO 9 (3%) и ECHO 25 (3%). В2008 г. большая часть выявленных у населения Новосибирской области изолятов ЭВ, вызывавших симптомы менингита, принадлежала к генотипу ECHO 30 (76%). В2009 г. клинических образцов, содержавших изоляты генотипа ECHO 30, обнаружено не было, однако наибольшая доля выявленных энтеровирусов относился к генотипу Cox A2 (33%) и Cox A4 (22%).Таким образом, в2008 г. нами зафиксирована вспышка серозных менингитов, основным этиологическим фактором которых яв- лялся энтеровирус ECHO 30, а подъем заболеваемости в2009 г. связан с циркуляцией среди населения новых генотипов энтеровирусов. Исследованные штаммы были депонированы в международной базе GenBank под номерами KP258231-KP258235, HM559584

Detection of tick-borne pathogens in wild birds and their ticks in Western Siberia and high level of their mismatch

Abstract: The Tomsk region located in the south of Western Siberia is one of the most high-risk areas for tick-borne diseases due to elevated incidence of tick-borne encephalitis and Lyme disease in humans. Wild birds may be considered as one of the reservoirs for tick-borne pathogens and hosts for infected ticks. A high mobility of wild birds leads to unpredictable possibilities for the dissemination of tick-borne pathogens into new geographical regions. The primary goal of this study was to evaluate the prevalence of tick-borne pathogens in wild birds and ticks that feed on them as well as to determine the role of different species of birds in maintaining the tickborne infectious foci. We analysed the samples of 443 wild birds (60 species) and 378 ticks belonging to the genus Ixodes Latraille, 1795 collected from the wild birds, for detecting occurrence of eight tick-borne pathogens, the namely tick-borne encephalitis virus (TBEV), West Nile virus (WNV), and species of Borrelia, Rickettsia, Ehrlichia, Anaplasma, Bartonella and Babesia Starcovici, 1893, using RT-PCR/or PCR and enzyme immunoassay. One or more tick-borne infection markers were detected in 43 species of birds. All markers were detected in samples collected from fieldfare Turdus pilaris Linnaeus, Blyth’s reed warbler Acrocephalus dumetorum Blyth, common redstart Phoenicurus phoenicurus (Linnaeus), and common chaffinch Fringilla coelebs Linnaeus. Although all pathogens have been identified in birds and ticks, we found that in the majority of cases (75.5%), there were mismatches of pathogens in birds and ticks collected from them. Wild birds and their ticks may play an extremely important role in the dissemination of tick-borne pathogens into different geographical regions