15,374 research outputs found

    From Light Nuclei to Nuclear Matter. The Role of Relativity?

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    The success of non-relativistic quantum dynamics in accounting for the binding energies and spectra of light nuclei with masses up to A=10 raises the question whether the same dynamics applied to infinite nuclear matter agrees with the empirical saturation properties of large nuclei.The simple unambiguous relation between few-nucleon and many-nucleon Hamiltonians is directly related to the Galilean covariance of nonrelativistic dynamics. Relations between the irreducible unitary representations of the Galilei and Poincare groups indicate thatthe ``nonrelativistic'' nuclear Hamiltonians may provide sufficiently accurate approximations to Poincare invariant mass operators. In relativistic nuclear dynamics based on suitable Lagrangeans the intrinsic nucleon parity is an explicit, dynamically relevant, degree of freedom and the emphasis is on properties of nuclear matter. The success of this approach suggests the question how it might account for the spectral properties of light nuclei.Comment: conference proceedings "The 11th International Conference on Recent Progress in Many-Body Theories" to be published by World Scientifi

    Total scattering descriptions of local and cooperative distortions in the oxide spinel (Mg,Cu)Cr2O4 with dilute Jahn-Teller ions

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    The normal spinel oxide MgCr2O4 is cubic at room temperature while the normal spinel CuCr2O4 is tetragonal as a consequence of the Jahn-Teller nature of Cu2+ on the tetrahedral sites. Despite different end-member structures, complete solid solutions of Mg_{1-x}Cu_xCr2O4 can be prepared that display a first-order structural transition with composition x = 0.43 at room temperature. Reverse Monte Carlo analysis of total neutron scattering on data acquired between 300 K and 15 K on samples with x = 0.10, 0.20, and 0.43 provides unbiased local and average structure descriptions of the samples, including an understanding of the transition from local Jahn-Teller distortions in the cubic phase to cooperative distortions that result in a tetragonal structure. Distributions of continuous symmetry measures help to understand and distinguish distorted and undistorted coordination around the tetrahedral site in the solid solutions. Magnetic exchange bias is observed in field-cooled hysteresis loops of samples with dilute Cu2+ concentration and in samples with tetragonal--cubic phase coexistence around 300 K.Comment: 10 pages, 14 figure

    Superconducting On-chip Fourier Transform Spectrometer

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    The kinetic inductance effect is strongly nonlinear with applied current in NbTiN, TiN and NbN thin films. This can be utilized to realize novel devices. We present results from transmission lines made with these materials, where DC (current) control is used to modulate the phase velocity thereby enabling on-chip spectrometers. Utility of such compact spectrometers is discussed, along with their natural connection with parametric amplifiers

    Angiogenic Effect of Bioactive Borate Glass Microfibers and Beads in the Hairless Mouse

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    The purpose of this project was to investigate the angiogenic mechanism of bioactive borate glass for soft tissue repair in a \u27hairless\u27 SKH1 mouse model. Subcutaneous microvascular responses to bioactive glass microfibers (45S5, 13-93B3, and 13-93B3Cu) and bioactive glass beads (13-93, 13-93B3, and 13-93B3Cu) were assessed via: noninvasive imaging of skin microvasculature; histomorphometry of microvascular densities; and quantitative PCR measurements of mRNA expression of VEGF and FGF-2 cytokines. Live imaging via dorsal skin windows showed the formation at two weeks of a halo-like structure infused with microvessels surrounding implanted borate-based 13-93B3 and 13-93B3Cu glass beads, a response not observed with silicate-based 13-93 glass beads. Quantitative histomorphometry of tissues implanted with plugs of 45S5, 13-93B3, and 13-93B3Cu glass microfibers revealed microvascular densities that were 1.6-, 2.3-, and 2.7-times higher, respectively, than the sham control values whereas 13-93, 13-93B3, and 13-93B3Cu glass beads caused the microvascular density to increase 1.3-, 1.6-, and 2.5-fold, respectively, relative to sham controls. Quantitative PCR measurements indicate a marginally significant increased expression of VEGF mRNA in tissues with 13-93B3Cu glass beads, an outcome that supported the hypothesis that copper-doped borate glass could promote VEGF expression followed by angiogenesis for enhanced wound healing

    Scaffold for Tissue Regeneration in Mammals

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    A three-dimensional scaffold with interconnected pores for repair of tissue comprising a scaffold body for structural support of the tissue scaffold, where the scaffold body comprises scaffold body components bonded to each other and made from component materials comprising about 40 to about 90 wt % B2O3, and two or more other oxides, wherein the scaffold body has a porosity between about 15 and about 90 vol %

    The Arecibo L-band Feed Array Zone of Avoidance Survey I: Precursor Observations through the Inner and Outer Galaxy

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    The Arecibo L-band Feed Array (ALFA) is being used to conduct a low-Galactic latitude survey, to map the distribution of galaxies and large-scale structures behind the Milky Way through detection of galaxies' neutral hydrogen (HI) 21-cm emission. This Zone of Avoidance (ZOA) survey finds new HI galaxies which lie hidden behind the Milky Way, and also provides redshifts for partially-obscured galaxies known at other wavelengths. Before the commencement of the full survey, two low-latitude precursor regions were observed, totalling 138 square degrees, with 72 HI galaxies detected. Detections through the inner Galaxy generally have no cataloged counterparts in any other waveband, due to the heavy extinction and stellar confusion. Detections through the outer Galaxy are more likely to have 2MASS counterparts. We present the results of these precursor observations, including a catalog of the detected galaxies, with their HI parameters. The survey sensitivity is well described by a flux- and linewidth-dependent signal-to-noise ratio of 6.5. ALFA ZOA galaxies which also have HI measurements in the literature show good agreement between our measurements and previous work. The inner Galaxy precursor region was chosen to overlap the HI Parkes Zone of Avoidance Survey so ALFA performance could be quickly assessed. The outer Galaxy precursor region lies north of the Parkes sky. Low-latitude large-scale structure in this region is revealed, including an overdensity of galaxies near l = 183 deg and between 5000 - 6000 km/s in the ZOA. The full ALFA ZOA survey will be conducted in two phases: a shallow survey using the observing techniques of the precursor observations, and also a deep phase with much longer integration time, with thousands of galaxies predicted for the final catalog.Comment: 26 pages, 7 figures, 2 tables, Astronomical Journal accepte

    Bacterial Cholangitis, Cholecystitis, or both in Dogs

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    BACKGROUND: Bacterial cholangitis and cholecystitis are rarely reported, poorly characterized diseases in the dog. OBJECTIVES: To characterize the clinical features of these conditions. ANIMALS: Twenty‐seven client‐owned dogs with bacterial cholangitis, cholecystitis, or both. METHODS: Multicenter, retrospective cases series of dogs with bacterial cholangitis, cholecystitis, or both, presenting January 2000 to June 2011 to 4 Veterinary Schools in Ireland/United Kingdom. Interrogation of hospital databases identified all cases with the inclusion criteria; histopathologically confirmed cholangitis or cholecystitis and bile culture/cytology results supporting a bacterial etiology. RESULTS: Twenty‐seven dogs met the inclusion criteria with approximately 460 hepatitis cases documented over the same study period. Typical clinical pathology findings were increases in liver enzyme activities (25/26), hyperbilirubinemia (20/26), and an inflammatory leukogram (21/24). Ultrasound findings, although nonspecific, aided decision‐making in 25/26 cases. The most frequent hepatobiliary bacterial isolates were Escherichia coli (n = 17; 16 cases), Enterococcus spp. (n = 8; 6 cases), and Clostridium spp. (n = 5; 5 cases). Antimicrobial resistance was an important feature of aerobic isolates; 10/16 E. coli isolates resistant to 3 or more antimicrobial classes. Biliary tract rupture complicated nearly one third of cases, associated with significant mortality (4/8). Discharged dogs had a guarded to fair prognosis; 17/18 alive at 2 months, although 5/10 re‐evaluated had persistent liver enzyme elevation 2–12 months later. CONCLUSION AND CLINICAL SIGNIFICANCE: Bacterial cholangitis and cholecystitis occur more frequently than suggested by current literature and should be considered in dogs presenting with jaundice and fever, abdominal pain, or an inflammatory leukogram or with ultrasonographic evidence of gallbladder abnormalities

    IT-technology in the budgeting

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    Budgeting plays an important role in modern organization, it is the tool that is necessary for the survival of the company in a competitive environment. Budgeting has become necessary business management process, and like any management activities, it requires automation

    Critical Temperature tuning of Ti/TiN multilayer films suitable for low temperature detectors

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    We present our current progress on the design and test of Ti/TiN Multilayer for use in Kinetic Inductance Detectors (KIDs). Sensors based on sub-stoichiometric TiN film are commonly used in several applications. However, it is difficult to control the targeted critical temperature TCT_C, to maintain precise control of the nitrogen incorporation process and to obtain a production uniformity. To avoid these problems we investigated multilayer Ti/TiN films that show a high uniformity coupled with high quality factor, kinetic inductance and inertness of TiN. These features are ideal to realize superconductive microresonator detectors for astronomical instruments application but also for the field of neutrino physics. Using pure Ti and stoichiometric TiN, we developed and tested different multilayer configuration, in term of number of Ti/TiN layers and in term of different interlayer thicknesses. The target was to reach a critical temperature TCT_C around (1÷1.5)(1\div 1.5) K in order to have a low energy gap and slower recombination time (i.e. low generation-recombination noise). The results prove that the superconductive transition can be tuned in the (0.5÷4.6)(0.5\div 4.6) K temperature range properly choosing the Ti thickness in the (0÷15)(0\div 15) nm range, and the TiN thickness in the (5÷100)(5\div 100) nm rang
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