Acute intestinal infections remain a significant problem for the majority of economically developed countries. Acute intestinal infection disease incidence in the structure of infectious pathology ...steadily ranks the 2nd place after acute virus respiratory infections. The urgency of the acute intestinal infections problem is connected with the frequent occurrence of clusters of cases ( outbreaks ) .The last mass and the largest in the last 20 years outbreak of acute intestinal infection , was detected in St. Petersburg in 2013. The Russian Federation takes one of the first places in the world in the number of migrants. The usage of food , stored or cooked with violation of sanitary rules contributes to infection and a high prevalence of intestinal infections among migrants. In the process of medical care when analysing the outbreak among migrants a number of requirements and problems was revealed; solving these problems will make it possible to stop similar epidemic situations during the shortest period and at the lowest cost.
Acute intestinal infections remain a significant problem for the majority of economically developed countries. Acute intestinal infection disease incidence in the structure of infectious pathology ...steadily ranks the 2nd place after acute virus respiratory infections. The urgency of the acute intestinal infections problem is connected with the frequent occurrence of clusters of cases ( outbreaks ) .The last mass and the largest in the last 20 years outbreak of acute intestinal infection , was detected in St. Petersburg in 2013. The Russian Federation takes one of the first places in the world in the number of migrants. The usage of food , stored or ooked with violation of sanitary rules contributes to infection and a high prevalence of intestinal infections among migrants. In the process of medical care when analysing the outbreak among migrants a number of requirements and problems was revealed; solving these problems will make it possible to stop similar epidemic situations during the shortest period and at the lowest cost.
Comprehensive knowledge of the dynamic behaviour of electrons in condensed-matter systems is pertinent to the development of many modern technologies, such as semiconductor and molecular electronics, ...optoelectronics, information processing and photovoltaics. Yet it remains challenging to probe electronic processes, many of which take place in the attosecond (1 as = 10-18 s) regime. In contrast, atomic motion occurs on the femtosecond (1 fs = 10-15 s) timescale and has been mapped in solids in real time using femtosecond X-ray sources. Here we extend the attosecond techniques previously used to study isolated atoms in the gas phase to observe electron motion in condensed-matter systems and on surfaces in real time. We demonstrate our ability to obtain direct time-domain access to charge dynamics with attosecond resolution by probing photoelectron emission from single-crystal tungsten. Our data reveal a delay of approximately 100 attoseconds between the emission of photoelectrons that originate from localized core states of the metal, and those that are freed from delocalized conduction-band states. These results illustrate that attosecond metrology constitutes a powerful tool for exploring not only gas-phase systems, but also fundamental electronic processes occurring on the attosecond timescale in condensed-matter systems and on surfaces.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We apply our recently suggested statistical approach to thermal evolution of isolated neutron stars and accreting quasi-stationary neutron stars in X-ray transients for constraining the position and ...relative broadening α of the direct Urca threshold of powerful neutrino emission in neutron star cores. We show that most likely explanation of observations corresponds to α ≈ 0.08–0.10 and to the neutron star mass, at which the direct Urca process is open, M
D ≈ 1.6–1.8 M⊙.
The fast dephasing of electron spins in an ensemble of quantum dots is detrimental for applications in quantum information processing. We show here that dephasing can be overcome by using a periodic ...train of light pulses to synchronize the phases of the precessing spins, and we demonstrate this effect in an ensemble of singly charged (In,Ga)As/GaAs quantum dots. This mode locking leads to constructive interference of contributions to Faraday rotation and presents potential applications based on robust quantum coherence within an ensemble of dots.
We describe a new attosecond FROG algorithm optimized for the characterization of sub-100 as pulses from streaked electron spectra. We make improvements upon the treatment of the attosecond streaking ...spectrogram, and show that these are necessary in order to accurately characterize shorter pulses with ever larger bandwidths. We investigate the effects of the approximations that must be made in order to apply the generalized projections scheme.
The sea urchin egg cortex is a peripheral region of eggs comprising a cell membrane and adjacent cytoplasm, which contains actin and tubulin cytoskeleton, cortical granules and some proteins required ...for early development. Method for isolation of cortices from sea urchin eggs and early embryos was developed in 1970s. Since then, this method has been reliable tool to study protein localization and cytoskeletal organization in cortex of unfertilized eggs and embryos during first cleavages. This study was aimed to estimate the reliability of RT-qPCR to analyze levels of maternal transcripts that are localized in egg cortex. Firstly, we selected seven potential reference genes, 28S, Cycb, Ebr1, GAPDH, Hmg1, Smtnl1 and Ubb, the transcripts of which are maternally deposited in sea urchin eggs. The candidate reference genes were ranked by five different algorithms (BestKeeper, CV, ΔCt, geNorm and NormFinder) based on calculated level of stability in both eggs as well as isolated cortices. Our results showed that gene ranking differs in total RNA and mRNA samples, though Ubb is most suitable reference gene in both cases. To validate feasibility of comparative analysis of eggs and isolated egg cortices, we selected Daglb-2 as a gene of interest, which transcripts are potentially localized in cortex according to transcriptome analysis, and observed increased level of Daglb-2 in egg cortices by RT-qPCR. This suggests that proposed RNA isolation method with subsequent quantitative RT-qPCR analysis can be used to determine cortical association of transcripts in sea urchin eggs.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In semiconductors, quantum confinement can greatly enhance the interaction between band carriers (electrons and holes) and dopant atoms. One manifestation of this enhancement is the increased ...stability of exciton magnetic polarons in magnetically doped nanostructures. In the limit of very strong 0D confinement that is realized in colloidal semiconductor nanocrystals, a single exciton can exert an effective exchange field B ex on the embedded magnetic dopants that exceeds several tesla. Here we use the very sensitive method of resonant photoluminescence (PL) to directly measure the presence and properties of exciton magnetic polarons in colloidal Cd1–x Mn x Se nanocrystals. Despite small Mn2+ concentrations (x = 0.4–1.6%), large polaron binding energies up to ∼26 meV are observed at low temperatures via the substantial Stokes shift between the pump laser and the resonant PL maximum, indicating nearly complete alignment of all Mn2+ spins by B ex. Temperature and magnetic field-dependent studies reveal that B ex ≈ 10 T in these nanocrystals, in good agreement with theoretical estimates. Further, the emission line widths provide direct insight into the statistical fluctuations of the Mn2+ spins. These resonant PL studies provide detailed insight into collective magnetic phenomena, especially in lightly doped nanocrystals where conventional techniques such as nonresonant PL or time-resolved PL provide ambiguous results.
The article describes the development stages of an adequate regulatory structure for the slope stability in open pit mines. Some supplementary factors that have influence on stability of slopes in ...open pit mines in the gravity–tectonic stress field are discussed. The main trends of research of pitwall rock mass in operating surface mines are presented, and the necessity of determining the tectonic stresses in pitwall rock mass and taking into account their impact on slope stability is emphasized. The algorithm is developed for justifying slope parameters for open pit mines under tectonic stresses, the drilling-and-blasting principles are formulated for the operation in pitwall rock mass, and the methods are proposed to mitigate the blasting-induced impact on adjacent rocks.
Near the surface of any neutron star there is a thin heat blanketing envelope that produces substantial thermal insulation of warm neutron star interiors and that relates the internal temperature of ...the star to its effective surface temperature. Physical processes in the blanketing envelopes are reasonably clear but the chemical composition is not. The latter circumstance complicates inferring physical parameters of matter in the stellar interiors from observations of the thermal surface radiation of the stars and urges one to elaborate the models of blanketing envelopes. We outline physical properties of these envelopes, particularly, the equation of state, thermal conduction, ion diffusion and others. Various models of heat blankets are reviewed, such as composed of separate layers of different elements, or containing diffusive binary ion mixtures in or out of diffusion equilibrium. The effects of strong magnetic fields in the envelopes are outlined as well as the effects of high temperatures which induce strong neutrino emission in the envelopes themselves. Finally, we discuss how the properties of the heat blankets affect thermal evolution of neutron stars and the ability to infer important information on internal structure of neutron stars from observations.
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