548 research outputs found

    Capillary Dynamics of Water/Ethanol Mixtures

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    Surface tension and contact angle play important roles in capillary dynamics during washing commission of spray-dried detergent powder where interaction between surface chemistry and liquid is concerned. An experimental study for the dynamics of water/ethanol mixtures in both hydrophilic and hydrophobic capillary tubes has been investigated. The combination of water/ethanol mixtures and trimethylchlorosilane coating on capillaries provides a variety of liquid surface tension and contact angle for the penetrating system. Significant differences of penetrating speed on hydrophilic and hydrophobic tubes indicate that dynamic contact angle dominates the hydrophobic surface while liquid surface tension plays a more important role on the hydrophilic surface. The speed gradient of different liquids on hydrophilic surface is greater than the hydrophobic surface, mainly due to the domination between hydrogen bonding structures and water polarity while liquid moves on surfaces covered with different chemistry, physically absorbed water on silica capillaries or silanol group covered capillaries

    Anomalous spectral weight in photoemission spectra of the hole doped Haldane chain Y2-xSrxBaNiO5

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    In this paper, we present photoemission experiments on the hole doped Haldane chain compound Y2−xSrxBaNiO5Y_{2-x}Sr_xBaNiO_5. By using the photon energy dependence of the photoemission cross section, we identified the symmetry of the first ionisation states (d type). Hole doping in this system leads to a significant increase in the spectral weight at the top of the valence band without any change in the vicinity of the Fermi energy. This behavior, not observed in other charge transfer oxides at low doping level, could result from the inhomogeneous character of the doped system and from a Ni 3d-O 2p hybridization enhancement due to the shortening of the relevant Ni-O distance in the localized hole-doped regions.Comment: 5 pages, 4 figure

    Sequestered Dark Matter

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    We show that hidden-sector dark matter is a generic feature of the type IIB string theory landscape and that its lifetime may allow for a discovery through the observation of very energetic gamma-rays produced in the decay. Throats or, equivalently, conformally sequestered hidden sectors are common in flux compactifications and the energy deposited in these sectors can be calculated if the reheating temperature of the standard model sector is known. Assuming that throats with various warp factors are available in the compact manifold, we determine which throats maximize the late-time abundance of sequestered dark matter. For such throats, this abundance agrees with cosmological data if the standard model reheating temperature was 10^10 - 10^11 GeV. In two distinct scenarios, the mass of dark matter particles, i.e. the IR scale of the throat, is either around 10^5 GeV or around 10^10 GeV. The lifetime and the decay channels of our dark matter candidates depend crucially on the fact that the Klebanov-Strassler throat is supersymmetric. Furthermore, the details of supersymmetry breaking both in the throat and in the visible sector play an essential role. We identify a number of scenarios where this type of dark matter can be discovered via gamma-ray observations.Comment: 36 pages, 3 figures; v2: references added, v3: introduction extended and typos correcte

    The Shape of Gravity in a Warped Deformed Conifold

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    We study the spectrum of the gravitational modes in Minkowski spacetime due to a 6-dimensional warped deformed conifold, i.e., a warped throat, in superstring theory. After identifying the zero mode as the usual 4D graviton, we present the KK spectrum as well as other excitation modes. Gluing the throat to the bulk (a realistic scenario), we see that the graviton has a rather uniform probability distribution everywhere while a KK mode is peaked in the throat, as expected. Due to the suppressed measure of the throat in the wave function normalization, we find that a KK mode's probability in the bulk can be comparable to that of the graviton mode. We also present the tunneling probabilities of a KK mode from the inflationary throat to the bulk and to another throat. Due to resonance effect, the latter may not be suppressed as natively expected. Implication of this property to reheating after brane inflation is discussed

    Impact of the COVID-19 pandemic on the care of cancer patients in Spain

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    Coronavirus SARS-CoV-2; COVID-19; 2019-nCoV; Càncer; EspanyaCoronavirus SARS-CoV-2; COVID-19; 2019-nCoV; Cåncer; EspañaCoronavirus SARS-CoV-2; COVID-19; 2019-nCoV; Cancer; SpainBackground Studies evaluating the effects of the COVID-19 pandemic on public healthcare systems are limited, particularly in cancer management. As no such studies have been carried out in Spain, our objective is to describe and quantify the impact of the COVID-19 pandemic on cancer patients in Spanish hospitals during the first wave of the pandemic. Materials and methods This retrospective, multicenter, nationwide study collected information from hospital departments treating oncology patients. An electronic questionnaire comparing outcomes and management of oncohematological patients for the March-June 2019 and March-June 2020 periods was used. Results Information from 78 departments (36 tertiary hospitals) was analyzed. Forty-four departments implemented adapted protocols during March 2020. Most of these (n = 38/44; 86.4%) carried out COVID-19 triage, while 26 of 44 (59.1%) carried out onsite polymerase chain reaction tests for clinically suspected cases. A shift from in-person to telephone visits was observed in 43 of 44 (97.7%) departments. Comparing the March-June 2019 and March-June 2020 periods, the number of new patients decreased by 20.8% (from 160.2 to 126.4). Decreases were also seen in the mean number of total (2858.2 versus 1686.1) and cancer (465.5 versus 367.2) biopsies, as well as the mean number of bone marrow biopsies (30.5 versus 18.6). Concerning the number of patients visiting specific cancer care departments, a decrease from 2019 to 2020 was seen for mean number of chemotherapy treatments (712.7 versus 643.8) and radiation therapy (2169.9 versus 2139.9). Finally, a reduction from 2019 to 2020 of 12.9% (from 8.6 to 7.4) in the mean number of patients included in clinical trials was noted. Conclusions This study provides the first comprehensive data concerning the impact of COVID-19 on cancer care in Spain. The pandemic caused a 20.8% decrease in newly diagnosed patients, which may impact future outcomes. Measures must be taken to ensure cancer management receives priority in times of healthcare emergencies.This work was supported by funding from the AECC, a non-profit organization, whose medical department funded the study and the medical writing (no grant number)

    Glueballs, symmetry breaking and axionic strings in non-supersymmetric deformations of the Klebanov-Strassler background

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    We obtain an analytic solution for an axionic non-supersymmetric deformation of the warped deformed conifold. This allows us to study D-strings in the infrared limit of non-supersymmetric deformations of the Klebanov-Strassler background. They are interpreted as axionic strings in the dual field theory. Following the arguments of [hep-th/0405282], the axion is a massless pseudo-scalar glueball which is present in the supergravity fluctuation spectrum and it is interpreted as the Goldstone boson of the spontaneously broken U(1) baryon number symmetry, being the gauge theory on the baryonic branch. Besides, we briefly discuss about the Pando Zayas-Tseytlin solution where the SU(2) \times SU(2) global symmetry is spontaneously broken. This background has been conjectured to be on the mesonic branch of the gauge theory.Comment: 30 pages; V2: minor corrections; V3: section 3 corrected and misprints corrected to match version published in JHE

    POSITION PAPER OF THE CATALAN SOCIETY OF GASTROENTEROLOGY ABOUT HEPATIC ELASTOGRAPHY 2022

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    After almost 20 years using transient elastography (TE) for the non-invasive diagnosis of liver fibrosis, its use has been extended to population screening, evaluation of steatosis and complications of cirrhosis. For this reason, the "Catalan Society of Digestology" commissioned a group of experts to update the first Document carried out in 2011.The working group (8 doctors and 4 nurses) prepared a panel of questions based on the online survey "Hepatic Elastography in Catalonia 2022" following the PICO structure and the Delphi method.The answers are presented with the level of evidence, the degree of recommendation and the final consensus after being evaluated by 2 external reviewers.TE uses the simplest and most reliable elastographic method to quantify liver fibrosis, assess steatosis, and determine the risk of complications in patients with cirrhosis.Copyright © 2022 Elsevier España, S.L.U. All rights reserved

    Drag Force in a Charged N=4 SYM Plasma

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    Following recent developments, we employ the AdS/CFT correspondence to determine the drag force exerted on an external quark that moves through an N=4 super-Yang-Mills plasma with a non-zero R-charge density (or, equivalently, a non-zero chemical potential). We find that the drag force is larger than in the case where the plasma is neutral, but the dependence on the charge is non-monotonic.Comment: 16 pages, 1 eps figure; v2: references added, typos fixed; v3: more general ansatz, new nontrivial solution obtained, nonmonotonicity of the drag force made explicit in new figure, version to appear in JHE

    Glueballs of Super Yang-Mills from Wrapped Branes

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    In this paper we study qualitative features of glueballs in N=1 SYM for models of wrapped branes in IIA and IIB backgrounds. The scalar mode, 0++ is found to be a mixture of the dilaton and the internal part of the metric. We carry out the numerical study of the IIB background. The potential found exhibits a mass gap and produces a discrete spectrum without any cut-off. We propose a regularization procedure needed to make these states normalizable.Comment: 22 pages plus a appendixes, 2 figure
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