545 research outputs found

    DEGENERATIVE SPINE INJURY ASSOCIATED WITH BACK PAIN: MORPHOGENETIC ASPECTS

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    Degeneration of the intervertebral disk (IVD) is a pathological process resulting from an interplay between genetic and environmental factors causing structural and functional damage of the IVD and neighboring structures. It is the first stage of degenerative cascade in the vertebral motion segment. Initiation and progression of IVD degenerative processes traditionally involves several factors: inadequate mechanical load, decreased diffusion of nutrients through the arch laminae, and genetic factors playing a significant role in the development  of degenerative changes. Three categories of candidate genes whose coding variants are associated with different forms of degenerative changes in the IVD are identified, a conceptual model of genetic interactions in degenerative disease of the disk is developed. The study  of the role of structural changes in back pain genesis, evaluation of risk factors allow to optimize the tactics of patient care and find new therapeutic solutions preventing disease progression

    The Tully-Fisher Relation and H_not

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    The use of the Tully-Fisher (TF) relation for the determination of the Hubble Constant relies on the availability of an adequate template TF relation and of reliable primary distances. Here we use a TF template relation with the best available kinematical zero-point, obtained from a sample of 24 clusters of galaxies extending to cz ~ 9,000 km/s, and the most recent set of Cepheid distances for galaxies fit for TF use. The combination of these two ingredients yields H_not = 69+/-5 km/(s Mpc). The approach is significantly more accurate than the more common application with single cluster (e.g. Virgo, Coma) samples.Comment: 10 pages, including 2 figures and 1 table; uses AAS LaTex. Submitted to ApJ Letter

    Discovery of Recent Star Formation in the Extreme Outer Regions of Disk Galaxies

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    We present deep Halpha images of three nearby late-type spiral galaxies (NGC628, NGC1058 and NGC6946), which reveal the presence of HII regions out to, and beyond, two optical radii (defined by the 25th B-band isophote). The outermost HII regions appear small, faint and isolated, compared to their inner disk counterparts, and are distributed in organized spiral arm structures, likely associated with underlying HI arms and faint stellar arms. The relationship between the azimuthally--averaged Halpha surface brightness (proportional to star formation rate per unit area) and the total gas surface density is observed to steepen considerably at low gas surface densities. We find that this effect is largely driven by a sharp decrease in the covering factor of star formation at large radii, and not by changes in the rate at which stars form locally. An azimuthally--averaged analysis of the gravitational stability of the disk of NGC6946 reveals that while the existence of star formation in the extreme outer disk is consistent with the Toomre-Q instability model, the low rates observed are only compatible with the model when a constant gaseous velocity dispersion is assumed. We suggest that observed behaviour could also be explained by a model in which the star formation rate has an intrinsic dependence on the azimuthally-averaged gas volume density, which decreases rapidly in the outer disk due to the vertical flaring of the gas layer.Comment: 10 pages, 2 embedded postscript files, 3 jpeg images; accepted for publication in ApJ Letter

    The Molecular ISM of Dwarf Galaxies on Kiloparsec Scales: A New Survey for CO in Northern, IRAS-detected Dwarf Galaxies

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    We present a new survey for CO in dwarf galaxies using the Kitt Peak 12m telescope. We observed the central regions of 121 northern dwarfs with IRAS detections and no known CO emission. We detect CO in 28 of these galaxies and marginally detect another 16, increasing by about 50% the number of such galaxies known to have significant CO emission. The galaxies we detect are comparable in mass to the LMC, although somewhat brighter in CO and fainter in the FIR. Within dwarfs, we find that the CO luminosity, L_CO, is most strongly correlated with the K-band and the far infrared luminosities. There are also strong correlations with the radio continuum and B-band luminosities, and linear diameter. We suggest that L_CO and L_K correlate well because the stellar component of a galaxy dominates the midplane gravitational field and thus sets the pressure of the atomic gas, which controls the formation of H_2 from HI. We compare our sample with more massive galaxies and find that dwarfs and large galaxies obey the same relationship between CO and the 1.4 GHz radio continuum (RC) surface brightness. This relationship is well described by a Schmidt Law with Sigma_RC proportional to Sigma_CO^1.3. Therefore, dwarf galaxies and large spirals exhibit the same relationship between molecular gas and star formation rate (SFR). We find that this result is robust to moderate changes in the RC-to-SFR and CO-to-H_2 conversion factors. Our data appear to be inconsistent with large (order of magnitude) variations in the CO-to-H_2 conversion factor in the star forming molecular gas. [abridged]Comment: 28 pages, 14 figures, 5 tables, ApJ accepte

    Комплексные болевые синдромы в практике врача-интерниста: диагностика, лечение

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    The paper presents the basic criteria for diagnosing complex regional pain syndromes, the most important links of their pathogenesis and the specific features of their clinical picture. Much attention is given to their treatment options, including these with nonsteroidal anti-inflammatory drugs.Представлены основные критерии диагностики, важнейшие звенья патогенеза и особенности клинической картины комплексных региональных болевых синдромов. Большое внимание уделено способам лечения патологии, в том числе и нестероидными противовоспалительными препаратами

    Efficiency Estimation of the Single- and Multicomponent Anti-hydrate Reagents

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    Different types of technological and technical problems in the oil, gas and chemical industries are connected with the hydrate formation process and with the using of anti-hydrate chemicals. That is why, it is necessary to estimate thermobaric ranges within which reagents does not let hydrate to grow or is their dissociation. Also, to estimate anti-hydrate influence we need to determine the chemicals’ anti-hydrate efficiency and chose the best one. They make the reagents consisting of several chemical components depending on the purpose of their application – for prevention of formation and (or) elimination of hydrates. It demands calculations of the optimum concentration and expenses and also the intensity (speed) of hydrates dissociation causing with the reagents. The analytical method of the anti-hydrate chemical reagents efficiency determination containing one or several components from different classes of chemical compounds – alcohols, salts, acids, compounds of nitrogen and oxygen – is presented in this paper. With its help it is possible to define decrease in temperature of hydrate formation from reagents influence, to count key parameters of reagents anti-hydrate efficiency depending on component compositions of hydrate gas and a phase condition of a hydrate-gas system, to select types of chemical components and their quantity in multicomponent reagents, i.e., to make new compounds. The method can be used for express assessment of anti-hydrate chemical reagents efficiency on criteria sign for practical application in oil, gas and processing industry

    HI power spectrum of the spiral galaxy NGC628

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    We have measured the HI power spectrum of the nearly face-on spiral galaxy NGC628 (M74) using a visibility based estimator. The power spectrum is well fitted by a power law P(U)=AUαP(U)=AU^{\alpha}, with α=1.6±0.2\alpha =- 1.6\pm0.2 over the length scale 800pcto8kpc800 {\rm pc} {\rm to} 8 {\rm kpc}. The slope is found to be independent of the width of the velocity channel. This value of the slope is a little more than one in excess of what has been seen at considerably smaller length scales in the Milky-Way, Small Magellanic Cloud (LMC), Large Magellanic Cloud (SMC) and the dwarf galaxy DDO210. We interpret this difference as indicating a transition from three dimensional turbulence at small scales to two dimensional turbulence in the plane of the galaxy's disk at length scales larger than galaxy's HI scale height. The slope measured here is similar to that found at large scales in the LMC. Our analysis also places an upper limit to the galaxy's scale height at $800\ {\rm pc}$ .Comment: 4 Pages, 2 Figures, 1 Table. Accepted for Publication in MNRAS LETTER

    Investigation, Development, and Evaluation of Performance Proving for Fault-tolerant Computers

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    A number of methodologies for verifying systems and computer based tools that assist users in verifying their systems were developed. These tools were applied to verify in part the SIFT ultrareliable aircraft computer. Topics covered included: STP theorem prover; design verification of SIFT; high level language code verification; assembly language level verification; numerical algorithm verification; verification of flight control programs; and verification of hardware logic

    HIP AND BUTTOCKS PAIN SYNDROME — LOOK OF THE INTERNIST

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    Differential approach to the diagnosis of diseases associated with pain in the hips and buttocks is presented in this lecture

    Design study of Software-Implemented Fault-Tolerance (SIFT) computer

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    Software-implemented fault tolerant (SIFT) computer design for commercial aviation is reported. A SIFT design concept is addressed. Alternate strategies for physical implementation are considered. Hardware and software design correctness is addressed. System modeling and effectiveness evaluation are considered from a fault-tolerant point of view
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