3,245 research outputs found

    Ultrasound scan to detect acalculous cholecystopathy in immunocompromised hosts with unexplained fever.

    Get PDF
    We found a significant prevalence of acalculous cholecystopathy in a group of patients with hematologic malignancies and unexplained fever. Ultrasound scan (US) detected a case of acute cholecystitis, two of gallbladder overdistension and biliary sludge, and one of striated gallbladder wall thickening. US proved effective in early identification of abdominal infection site

    Dynamic Anomalies of Fluids with Isotropic Doubled-Ranged Potential

    Full text link
    Using molecular dynamics simulations we investigate the ability of an analytical three-dimensional double well in reproducing static and dynamic anomalies found experimentally in liquid water. We find anomalous behavior in the stable region of the phase diagram if the outer minimum is deeper than the inner minimum. In the case of a deeper inner minimum, anomalous behavior is also present but inside the unstable region.Comment: 10 pages, two figure

    Characterization of Large Volume 3.5 x 8 inches LaBr3:Ce Detectors

    Full text link
    The properties of large volume cylindrical 3.5 x 8 inches (89 mm x 203 mm) LaBr3:Ce scintillation detectors coupled to the Hamamatsu R10233-100SEL photo-multiplier tube were investigated. These crystals are among the largest ones ever produced and still need to be fully characterized to determine how these detectors can be utilized and in which applications. We tested the detectors using monochromatic gamma-ray sources and in-beam reactions producing gamma rays up to 22.6 MeV; we acquired PMT signal pulses and calculated detector energy resolution and response linearity as a function of gamma-ray energy. Two different voltage dividers were coupled to the Hamamatsu R10233-100SEL PMT: the Hamamatsu E1198-26, based on straightforward resistive network design, and the LABRVD, specifically designed for our large volume LaBr3:Ce scintillation detectors, which also includes active semiconductor devices. Because of the extremely high light yield of LaBr3:Ce crystals we observed that, depending on the choice of PMT, voltage divider and applied voltage, some significant deviation from the ideally proportional response of the detector and some pulse shape deformation appear. In addition, crystal non-homogeneities and PMT gain drifts affect the (measured) energy resolution especially in case of high-energy gamma rays. We also measured the time resolution of detectors with different sizes (from 1x1 inches up to 3.5x8 inches), correlating the results with both the intrinsic properties of PMTs and GEANT simulations of the scintillation light collection process. The detector absolute full energy efficiency was measured and simulated up to gamma-rays of 30 Me

    A parametrization of the growth index of matter perturbations in various Dark Energy models and observational prospects using a Euclid-like survey

    Full text link
    We provide exact solutions to the cosmological matter perturbation equation in a homogeneous FLRW universe with a vacuum energy that can be parametrized by a constant equation of state parameter ww and a very accurate approximation for the Ansatz w(a)=w0+wa(1a)w(a)=w_0+w_a(1-a). We compute the growth index \gamma=\log f(a)/\log\Om_m(a), and its redshift dependence, using the exact and approximate solutions in terms of Legendre polynomials and show that it can be parametrized as γ(a)=γ0+γa(1a)\gamma(a)=\gamma_0+\gamma_a(1-a) in most cases. We then compare four different types of dark energy (DE) models: wΛw\LambdaCDM, DGP, f(R)f(R) and a LTB-large-void model, which have very different behaviors at z\gsim1. This allows us to study the possibility to differentiate between different DE alternatives using wide and deep surveys like Euclid, which will measure both photometric and spectroscopic redshifts for several hundreds of millions of galaxies up to redshift z2z\simeq 2. We do a Fisher matrix analysis for the prospects of differentiating among the different DE models in terms of the growth index, taken as a given function of redshift or with a principal component analysis, with a value for each redshift bin for a Euclid-like survey. We use as observables the complete and marginalized power spectrum of galaxies P(k)P(k) and the Weak Lensing (WL) power spectrum. We find that, using P(k)P(k), one can reach (2%, 5%) errors in (w0,wa)(w_0, w_a), and (4%, 12%) errors in (γ0,γa)(\gamma_0, \gamma_a), while using WL we get errors at least twice as large. These estimates allow us to differentiate easily between DGP, f(R)f(R) models and Λ\LambdaCDM, while it would be more difficult to distinguish the latter from a variable equation of state parameter or LTB models using only the growth index.}Comment: 29 pages, 7 figures, 6 table

    Identification and rejection of scattered neutrons in AGATA

    Full text link
    Gamma rays and neutrons, emitted following spontaneous fission of 252Cf, were measured in an AGATA experiment performed at INFN Laboratori Nazionali di Legnaro in Italy. The setup consisted of four AGATA triple cluster detectors (12 36-fold segmented high-purity germanium crystals), placed at a distance of 50 cm from the source, and 16 HELENA BaF2 detectors. The aim of the experiment was to study the interaction of neutrons in the segmented high-purity germanium detectors of AGATA and to investigate the possibility to discriminate neutrons and gamma rays with the gamma-ray tracking technique. The BaF2 detectors were used for a time-of-flight measurement, which gave an independent discrimination of neutrons and gamma rays and which was used to optimise the gamma-ray tracking-based neutron rejection methods. It was found that standard gamma-ray tracking, without any additional neutron rejection features, eliminates effectively most of the interaction points due to recoiling Ge nuclei after elastic scattering of neutrons. Standard tracking rejects also a significant amount of the events due to inelastic scattering of neutrons in the germanium crystals. Further enhancements of the neutron rejection was obtained by setting conditions on the following quantities, which were evaluated for each event by the tracking algorithm: energy of the first and second interaction point, difference in the calculated incoming direction of the gamma ray, figure-of-merit value. The experimental results of tracking with neutron rejection agree rather well with Geant4 simulations

    Combined biological therapy with lanreotide autogel and cabergoline in the treatment of MEN-1-related insulinomas.

    Get PDF
    Multiple endocrine neoplasia type 1 (MEN1) is a hereditary syndrome associated with the development of many endocrine tumors, involving mainly pituitary, parathyroids, pancreas, although a proliferative state interests all neuroendocrine system. MEN1 pancreatic neuroendocrine tumors (pNETs) are multiples and can secrete different hormones. The therapeutic approach is based on surgery which usually is followed by tumor relapse or persistence unless to be highly aggressive. Biotherapy with somatostatin analogs and dopamine agonists could be of great benefit to manage these patients without altering their life quality. We report a case of a 36-year-old MEN1 man affected with multicentric pNETs associated with insulinoma syndrome. Therapy with symptomatic agents (diazoxide), as well as biotherapy (lanreotide, cabergoline) was started. At 6-month follow-up, symptomatic agents were stopped and disease control was only based on lanreotide plus cabergoline. This combined biotherapy was able to control endocrine syndromes and tumor growth. Subsequently, a safer and selective surgical intervention on pNETs was performed. An excellent response to therapy with lanreotide autogel and cabergoline has been observed in a MEN1 patient with pNETs associated with insulinoma syndrome. The potential synergistic effects of lanreotide autogel and cabergoline on insulin-secreting neuroendocrine tumors are discussed

    Inoculação de Curtobacterium flaccumfaciens pv. flaccumfaciens em sementes de feijão por meio da técnica de condicionamento fisiológico.

    Get PDF
    Neste estudo foi testada a técnica de condicionamento fisiológico em meio agarizado para inoculação de Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff) em sementes de feijão. Na primeira etapa, avaliou-se o comportamento das sementes de feijão cultivar Pérola, durante o pré-condicionamento osmótico em substrato agarizado com restrição hídrica. Os tratamentos consistiram em expor, por diferentes períodos de tempo, sementes de feijão desinfestadas a quatro níveis de restrição hídrica do meio 523 (-0,55, -0,75, -0,95 e -1,15 MPa), com o uso de quatro substratos (meio 523, meio 523+KCl, meio 523+manitol e meio 523+sacarose). Como testemunha, utilizou-se o meio 523 sem restrição hídrica (-0,55 MPa). Decorridos os respectivos tempos, avaliou-se a percentagem de sementes com protrusão radicular e, posteriormente, o teor de água, a germinação e os padrões enzimáticos das sementes. Na segunda etapa do estudo, avaliou-se o crescimento de quatro isolados de Cff (Cff DF - Feij-2936, Cff PR - 12768, Cff SC - Feij-2928 e Cff SP - Feij-2634) em substrato agarizado com restrição hídrica. Os tratamentos da terceira etapa foram definidos com base na primeira etapa, em que o melhor tratamento foi o meio 523 com manitol no potencial hídrico de -0,95 MPa e com 48 horas de exposição das sementes no meio agarizado. Na segunda etapa, verificou-se que o isolado de Cff SC (Feij-2928), proveniente do estado de Santa Catarina, apresentou o melhor crescimento no substrato e no potencial hídrico definido na primeira etapa. Portanto, foi possível a inoculação artificial de sementes de feijão com Cff por meio da técnica de condicionamento fisiológico em substrato agarizado, sem o comprometimento de sua qualidade fisiológica

    Constraining primordial non-Gaussianity with cosmological weak lensing: shear and flexion

    Full text link
    We examine the cosmological constraining power of future large-scale weak lensing surveys on the model of \emph{Euclid}, with particular reference to primordial non-Gaussianity. Our analysis considers several different estimators of the projected matter power spectrum, based on both shear and flexion, for which we review the covariances and Fisher matrices. The bounds provided by cosmic shear alone for the local bispectrum shape, marginalized over σ8\sigma_8, are at the level of ΔfNL100\Delta f_\mathrm{NL} \sim 100. We consider three additional bispectrum shapes, for which the cosmic shear constraints range from ΔfNL340\Delta f_\mathrm{NL}\sim 340 (equilateral shape) up to ΔfNL500\Delta f_\mathrm{NL}\sim 500 (orthogonal shape). The competitiveness of cosmic flexion constraints against cosmic shear ones depends on the galaxy intrinsic flexion noise, that is still virtually unconstrained. Adopting the very high value that has been occasionally used in the literature results in the flexion contribution being basically negligible with respect to the shear one, and for realistic configurations the former does not improve significantly the constraining power of the latter. Since the flexion noise decreases with decreasing scale, by extending the analysis up to max=20,000\ell_\mathrm{max} = 20,000 cosmic flexion, while being still subdominant, improves the shear constraints by 10\sim 10% when added. However on such small scales the highly non-linear clustering of matter and the impact of baryonic physics make any error estimation uncertain. By considering lower, and possibly more realistic, values of the flexion intrinsic shape noise results in flexion constraining power being a factor of 2\sim 2 better than that of shear, and the bounds on σ8\sigma_8 and fNLf_\mathrm{NL} being improved by a factor of 3\sim 3 upon their combination. (abridged)Comment: 30 pages, 4 figures, 4 tables. To appear on JCA

    Unified Dark Matter models with fast transition

    Get PDF
    We investigate the general properties of Unified Dark Matter (UDM) fluid models where the pressure and the energy density are linked by a barotropic equation of state (EoS) p=p(ρ)p = p(\rho) and the perturbations are adiabatic. The EoS is assumed to admit a future attractor that acts as an effective cosmological constant, while asymptotically in the past the pressure is negligible. UDM models of the dark sector are appealing because they evade the so-called "coincidence problem" and "predict" what can be interpreted as wDE1w_{\rm DE} \approx -1, but in general suffer the effects of a non-negligible Jeans scale that wreak havoc in the evolution of perturbations, causing a large Integrated Sachs-Wolfe effect and/or changing structure formation at small scales. Typically, observational constraints are violated, unless the parameters of the UDM model are tuned to make it indistinguishable from Λ\LambdaCDM. Here we show how this problem can be avoided, studying in detail the functional form of the Jeans scale in adiabatic UDM perturbations and introducing a class of models with a fast transition between an early Einstein-de Sitter CDM-like era and a later Λ\LambdaCDM-like phase. If the transition is fast enough, these models may exhibit satisfactory structure formation and CMB fluctuations. To consider a concrete case, we introduce a toy UDM model and show that it can predict CMB and matter power spectra that are in agreement with observations for a wide range of parameter values.Comment: 30 pages, 15 figures, JHEP3 style, typos corrected; it matches the published versio

    Structural evolution in the neutron-rich nuclei 106Zr and 108Zr

    Get PDF
    The low-lying states in 106Zr and 108Zr have been investigated by means of {\beta}-{\gamma} and isomer spectroscopy at the RI beam factory, respectively. A new isomer with a half-life of 620\pm150 ns has been identified in 108Zr. For the sequence of even-even Zr isotopes, the excitation energies of the first 2+ states reach a minimum at N = 64 and gradually increase as the neutron number increases up to N = 68, suggesting a deformed sub-shell closure at N = 64. The deformed ground state of 108Zr indicates that a spherical sub-shell gap predicted at N = 70 is not large enough to change the ground state of 108Zr to the spherical shape. The possibility of a tetrahedral shape isomer in 108Zr is also discussed.Comment: 10 pages, 3 figures, Accepted for publication in Phys. Rev. Let
    corecore