1,794 research outputs found

    VASCULARIZATION OF THE UPPER LIMB ARTERIES

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    REGULARITIES OF THE VASCULARIZATION OF HUMAN ARTERIAL VESSELS

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    Muon Track Matching

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    For most physical processes the tracks observed in the muon stations must be matched with the corresponding tracks in the inner tracker, the external muon system providing muon identification and triggering but the tracker points giving the precise momentum measurement at lower momenta. For high momenta the momentum resolution is much improved by the interconnection of inner and outer measurements. The matching of outer and inner measurements is more delicate in case of muons embedded in jets. A study of the matching procedure was carried out using samples of (b, anti b) jets at high Pt, requiring (b, anti b) -> mu decays.For most physical processes the tracks observed in the muon stations must be matched with the corresponding tracks in the inner tracker, the external muon system providing muon identification and triggering but the tracker points giving the precise momentum measurement at lower momenta. For high momenta the momentum resolution is much improved by the interconnection of inner and outer measurements. The matching of outer and inner measurements is more delicate in case of muons embedded in jets. A study of the matching procedure was carried out using samples of (b, anti b) jets at high Pt, requiring (b, anti b) -> mu decays

    The nature of the highest energy cosmic rays

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    Ultra high energy gamma rays produce electron--positron pairs in interactions on the geomagnetic field. The pair electrons suffer magnetic bremsstrahlung and the energy of the primary gamma ray is shared by a bunch of lower energy secondaries. These processes reflect the structure of the geomagnetic field and cause experimentally observable effects. The study of these effects with future giant air shower arrays can identify the nature of the highest energy cosmic rays as either gamma-rays or nuclei.Comment: 15 pages of RevTeX plus 6 postscript figures, tarred, gzipped and uuencoded. Subm. to Physical Review

    Evaluating the effectiveness of acid treatment in turnaisian formation of Perm region

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    The article presents the results of the use of acidic composition of DN-9010 for the stimulation of oil wells in the turnejskih deposits in deposits of Perm region. Authors assessed the impact of technological and geophysical parameters of layers on the success of the acid treatments, by comparing the rates of productivity and production wells before and after acid treatment. When the watercut increases and bottomhole pressure decreases the effectiveness of acid treatment decreases. With the growing volume of acid solution pumped per unit effective oil-acid, performance impact is increasing. Equation for predicting the coefficient obtained productivity wells after the acid treatment

    Fungal, bacterial, and archaeal diversity in the digestive tract of several beetle larvae (coleoptera)

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    © Copyright 2018 Elvira E. Ziganshina et al. Interpretation of how partnerships between fungi, bacteria, archaea, and insects are maintained through the life of the hosts is a big challenge within the framework of symbiosis research. The main goal of this work was to characterize the gut microbiota in larvae of several Coleoptera species using sequencing of the bacterial and archaeal 16S rRNA genes and fungal internal transcribed spacer (ITS) region. Thus, larvae with various food preferences, including Amphimallon solstitiale, Oryctes nasicornis, Cucujus cinnaberinus, Schizotus pectinicornis, Rhagium mordax, and Rhagium inquisitor, were thoroughly investigated in this work. We revealed an association of these beetle species mainly with four bacterial phyla, Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes, as well as with three fungal phyla, Ascomycota, Zygomycota, and Basidiomycota, but microbial communities varied depending on the beetle host, individual organism, and surrounding environment. Moreover, archaea within the phyla Euryarchaeota and Crenarchaeota in the hindgut content of O. nasicornis and A. solstitialewere additionally detected.The identified microbial communities suggest their potential role in the exploitation of various resources, providing nutritional needs for the host organism.These microorganisms can also represent a valuable source of novelmetabolic capacities for their application in different biotechnologies

    Ultra-High Energy Gamma Rays in Geomagnetic Field and Atmosphere

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    The nature and origin of ultra-high energy (UHE: reffering to > 10^19 eV) cosmic rays are great mysteries in modern astrophysics. The current theories for their explanation include the so-called "top-down" decay scenarios whose main signature is a large ratio of UHE gamma rays to protons. Important step in determining the primary composition at ultra-high energies is the study of air shower development. UHE gamma ray induced showers are affected by the Landau-Pomeranchuk-Migdal (LPM) effect and the geomagnetic cascading process. In this work extensive simulations have been carried out to study the characteristics of air showers from UHE gamma rays. At energies above several times 10^19 eV the shower is affected by geomagnetic cascading rather than by the LPM effect. The properties of the longitudinal development such as average depth of the shower maximum or its fluctuations depend strongly on both primary energy and incident direction. This feature may provide a possible evidence of the UHE gamma ray presence by fluorescence detectors.Comment: 27 pages, 12 figures, submitted to Phys.Rev.

    Ultrahigh Energy Gamma Ray Cascading in the Geomag- netic Field and Its Development in the Atmosphere

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    Abstract Extensive simulations of the longitudinal development of air showers from ultrahigh (UHE) energy gamma rays have been carried out. The shower development is affected by the geomagnetic cascading before entering the atmosphere and by the Landau-Pomeranchuk-Migdal effect in the atmosphere. AIRES code as well as our original code have been used for cascade simulations in the atmosphere. The analysis of the results shows that the longitudinal development of the showers depend strongly on both primary energy and incident direction. This feature may provide reliable conclusions about the photon fraction in the UHE ( > 5 × 10 19 eV) cosmic ray flux

    First bounds on the very high energy gamma-ray emission from Arp 220

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    Using the Major Atmospheric Gamma Imaging Cherenkov Telescope (MAGIC), we have observed the nearest ultra-luminous infrared galaxy Arp 220 for about 15 hours. No significant signal was detected within the dedicated amount of observation time. The first upper limits to the very high energy Îł\gamma-ray flux of Arp 220 are herein reported and compared with theoretical expectations.Comment: Accepted for publication in Ap
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