411 research outputs found
Dielectric responses of the layered cobalt oxysulfide Sr_2Cu_2CoO_2S_2 with CoO_2 square-planes
We have studied the dielectric responses of the layered cobalt oxysulfide
SrCuCoOS with the CoO square-planes. With decreasing
temperature below the N\'eel temperature, the resistivity increases like a
semiconductor, and the thermopower decreases like a metal. The dielectric
constant is highly dependent on temperature, and the dielectric relaxation is
systematically changed with temperature, which is strongly correlated to the
magnetic states. These behaviors suggest that carriers distributed
homogeneously in the paramagnetic state at high temperatures are expelled from
the antiferromagnetically ordered spin domain below the N\'eel temperature.Comment: 3 pages, 4 eps figures, to be published in J. Appl. Phy
Cool spots on the surface of the active giant PZ Mon
Based on the multiband (BVRIJHKL) photometric observations of the active red
giant PZ Mon performed for the first time in the winter season of 2017-2018, we
have determined the main characteristics of the spotted stellar surface in a
parametric three-spot model. The unspotted surface temperature is Teff=4730 K,
the temperature of the cool spots is Tspot=3500 K, their relative area is about
41%, and the temperature of the warm spots is Twarm=4500 K with a maximum
relative area up to 20%. The distribution of spots over the stellar surface has
been modeled. The warm spots have been found to be distributed at various
longitudes in the hemisphere on the side of the secondary component and are
most likely a result of its influence.Comment: 5 pages, 7 figure
Structure and distribution of the slope fish community in the vicinity of the sub-Antarctic Prince Edward Archipelago
Demersal fish community structure, distribution and trophic relationships on the slope (depth range 200–1500 m) of the sub-Antarctic Prince Edward Islands and surrounding sea rises were investigated during a pilot survey conducted in April 2001 onboard fishing vessel MV Iris. A total of 56 fish taxa were collected during the survey, of which 44 were identified to the species level, seven to the genus level and five to the family level. Among the identified taxa, 36 constituted new records for the area investigated. Total catch per unit effort (cpue) during the survey ranged from 1•1 to 241•2 individuals h 1. Both average fish diversity and total cpue positively correlated with trawling depth. Overall, mean sampling depth and near-bottom temperature explained 56% of total fish cpue. Hierarchal cluster analysis identified three distinct fish assemblages with pronounced dominant species. Major shifts in fish community composition occurred at 500–600 m and 800–900 m depth strata and could probably be a result of physical and biological vertical zonation. Analysis of the diet of selected fish species showed that they were generalist feeders, consuming predominantly pelagic, including epipelagic, meso- and benthopelagic, prey. Diets of six species and nitrogen stable isotope signatures of 22 species revealed that with a few exceptions most fishes occupied the fourth trophic level and were tertiary consumers. Wide variability in carbon isotopic signatures is discussed with respect to alternative, e.g. possible importance of high Antarctic and chemoautotrophic v. photoautotrophic sub-Antarctic primary production, organic matter sources at the base of deep-sea food webs
The role of RIG-I, AIM2 and IFI16 receptors for viral RNA and DNA in the pathogenesis of spontaneous and early missed miscarriage
Aim: to identify the features of the expression of mRNA of intracellular RIG-I, IFI16 and AIM2 receptors for viral RNA and DNA, and their signaling pathway proteins in the decidual tissue of patients with spontaneous and early missed miscarriage
Repolarization of ferroelectric superlattices BaZrO3/BaTiO3
The study was supported by Russian Science Foundation, project No. № 17-72-20105
Quantum Size Effect transition in percolating nanocomposite films
We report on unique electronic properties in Fe-SiO2 nanocomposite thin films
in the vicinity of the percolation threshold. The electronic transport is
dominated by quantum corrections to the metallic conduction of the Infinite
Cluster (IC). At low temperature, mesoscopic effects revealed on the
conductivity, Hall effect experiments and low frequency electrical noise
(random telegraph noise and 1/f noise) strongly support the existence of a
temperature-induced Quantum Size Effect (QSE) transition in the metallic
conduction path. Below a critical temperature related to the geometrical
constriction sizes of the IC, the electronic conductivity is mainly governed by
active tunnel conductance across barriers in the metallic network. The high 1/f
noise level and the random telegraph noise are consistently explained by random
potential modulation of the barriers transmittance due to local Coulomb
charges. Our results provide evidence that a lowering of the temperature is
somehow equivalent to a decrease of the metal fraction in the vicinity of the
percolation limit.Comment: 21 pages, 8 figure
Longitudinal and transversal piezoresistive response of granular metals
In this paper, we study the piezoresistive response and its anisotropy for a
bond percolation model of granular metals. Both effective medium results and
numerical Monte Carlo calculations of finite simple cubic networks show that
the piezoresistive anisotropy is a strongly dependent function of bond
probability p and of bond conductance distribution width \Delta g. We find that
piezoresistive anisotropy is strongly suppressed as p is reduced and/or \Delta
g is enhanced and that it vanishes at the percolation thresold p=p_c. We argue
that a measurement of the piezoresistive anisotropy could be a sensitive tool
to estimate critical metallic concentrations in real granular metals.Comment: 14 pages, 7 eps figure
Temperature effect on the temporal dynamic of terrestrial invertebrates in technosols formed after reclamation at a post-mining site in Ukrainian steppe drylands
The research was carried out at the Research Centre of the Dnipro State Agrarian and Economic University in Pokrov city. Sampling was carried out in 2013–2015 on a variant of artificial soil (technosols) formed on loess-like loam, red-brown clay, green-grey clay, technological mixture of rocks, and also formed on loess-like loam with a humus-rich 70 cm top soil layer. To investigate the spatiotemporal variation in the abundance, species richness and species composition of invertebrate assemblages within the experimental polygon, the animals were sampled using pitfall traps. In total, 60 pitfall traps were operated simultaneously during each sampling period. Each year the pitfalls were emptied 26 times every 7–9 days. Invertebrates (Arthropoda and Mollusca) of 6 classes, 13 orders, 50 families and 202 species or parataxonomic units were recorded. Diplopoda was most abundant taxonomic group, though it was represented by only one species Rossiulus kessleri (Lohmander, 1927). Coleoptera and Araneae were the most numerous taxonomic groups. Readily available water for plants, precipitation, wind speed, atmospheric temperature (daily minimum, daily maximum, daily mean), atmospheric humidity and atmospheric pressure were used as environmental predictors. Two dimension geographic coordinates of the sampling locations were used to generate a set of orthogonal eigenvector-based spatial variables. Time series of sampling dates were used to generate a set of orthogonal eigenvector-based temporal variables. The moisture content in the technosols was revealed to be the most important factor determining the temporal dynamics of the terrestrial invertebrate community in conditions of semi-arid climate and the ecosystem which formed as a result of the reclamation process. Following soil moisture, the factor most strongly affecting invertebrates in the technosols was temperature. From the total set of the invertebrates, two relatively homogeneous species groups in terms of thermal preferences were extracted: the microtemperature and mesotemperature groups. The microtemperature species are more tolerant to the thermal factor, and the mesotemperature species are more sensitive. The Huisman-Olff-Fresco approach expanded by Jansen-Oksanen provides a wide set of ecologically relevant models which are able to explain species response. The species response to temperature is affected by a complex of other environmental, temporal and spatial factors. The effect of other factors on the species response must be previously extracted to find real estimations of the species temperature optima and tolerance. The approaches to solving this problem may be the object of future investigation
Linguistic and statistically derived features for cause of death prediction from verbal autopsy text
Automatic Text Classification (ATC) is an emerging technology with economic importance given the unprecedented growth of text data. This paper reports on work in progress to develop methods for predicting Cause of Death from Verbal Autopsy (VA) documents recommended for use in low-income countries by the World Health Organisation. VA documents contain both coded data and open narrative. The task is formulated as a Text Classification problem and explores various combinations of linguistic and statistical approaches to determine how these may improve on the standard bag-of-words approach using a dataset of over 6400 VA documents that were manually annotated with cause of death. We demonstrate that a significant improvement of prediction accuracy can be obtained through a novel combination of statistical and linguistic features derived from the VA text. The paper explores the methods by which ATC may leads to improved accuracy in Cause of Death prediction
Expression of indaleamine 2,3-dioxygenase mRNA in patients with spontaneous miscarriages at early stages of pregnancy
Expression mRNA of indoleamine 2,3-dioxygenase (IDO) and Toll-like receptors (TLR) 1-4 in epithelial cells of cervix uteri in 57 patients with early stage miscarriages (6-10 weeks of pregnancy) and 57 patients with artificial abortion (control group) was examined using quantitative polymerase chain reaction (PCR
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