652 research outputs found

    Liaison and Scholarly Communication Librarians Collaborating to Support Faculty and Students

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    Chapter 18 of the ACRL publication titled, Approaches to Liaison Librarianship: Innovations in Organization and Engagements edited by Robin Canuel and Chad Crichton

    General Statistical properties of the CMB Polarization field

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    The distribution of the polarization of the Cosmic Microwave Background (CMB) in the sky is determined by the hypothesis of random Gaussian distribution of the primordial density perturbations. This hypotheses is well motivated by the inflationary cosmology. Therefore, the test of consistency of the statistical properties of the CMB polarization field with the Gaussianity of primordial density fluctuations is a realistic way to study the nature of primordial inhomogeneities in the Universe. This paper contains the theoretical predictions of the general statistical properties of the CMB polarization field. All results obtained under assumption of the Gaussian nature of the signal. We pay the special attention to the following two problems. First, the classification and statistics of the singular points of the polarization field where polarization is equal to zero. Second, the topology of contours of the value of the degree of polarization. We have investigated the percolation properties for the zones of ``strong'' and ``weak'' polarization. We also have calculated Minkowski functionals for the CMB polarization field. All results are analytical.Comment: Latex, 22 pages, including 5 figure

    Alternate Solutions to Water Resource Development -- A Case Study

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    This study was undertaken in an effort to develop procedural methodology for the consideration of alternative solutions for water resources development in a short period of time with a view toward reduction of total costs involved in prefeasibility studies. A review of related literature was made to reveal the status of the need for the development of a comprehensive method to evaluate possible alternatives. Three techniques were developed in this research effort to estimate the investment costs of a reservoir project, a levee project, and a basin conservation reservoir project in an economic region. The application of the methodologies were illustrated by a case study. The cost of a reservoir project in the case study area determined by the method developed in this investigation was in excellent agreement with the Corps of Engineers' estimate using conventional methods. In general, the dependability of all the three methodologies were considered good for use in order-ofmagnitude estimates. Selected solutions for water resources development problems in the Navasota River watershed were analyzed. The cost of water supply by desalination in the service area of the proposed Millican reservoir was computed following the procedure recommended by the Office of Saline Water. The investment costs of the alternatives were compared. The multipurpose reservoir project for flood control, water supply and recreation was found to be the least costly project. However, levees for flood protection in the lower Brazos River basin and desalting for water supply appeared to possess more intangible environmental benefits although the estimated cost of this multipurpose alternative was somewhat higher in comparison to the multipurpose reservoir project. Evaluation of intangible cost factors (environmental, aesthetic, etc.) was not possible in want of scientifically amenable procedures. Total costs (combined tangible and intangible factors) of all alternative plans could not be estimated. As a result, no attempt was made to recommend any specific alternative to the proposed action in the case study area

    A novel human aquaporin-4 splice variant exhibits a dominant-negative activity: a new mechanism to regulate water permeability.

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    Two major isoforms of aquaporin-4 (AQP4) have been described in human tissue. Here we report the identification and functional analysis of an alternatively spliced transcript of human AQP4, AQP4-Δ4, that lacks exon 4. In transfected cells AQP4-Δ4 is mainly retained in the endoplasmic reticulum and shows no water transport properties. When AQP4-Δ4 is transfected into cells stably expressing functional AQP4, the surface expression of the full-length protein is reduced. Furthermore, the water transport activity of the cotransfectants is diminished in comparison to transfectants expressing only AQP4. The observed down-regulation of both the expression and water channel activity of AQP4 is likely to originate from a dominant-negative effect caused by heterodimerization between AQP4 and AQP4-Δ4, which was detected in coimmunoprecipitation studies. In skeletal muscles, AQP4-Δ4 mRNA expression inversely correlates with the level of AQP4 protein and is physiologically associated with different types of skeletal muscles. The expression of AQP4-Δ4 may represent a new regulatory mechanism through which the cell-surface expression and therefore the activity of AQP4 can be physiologically modulated

    Klf6 protects β-cells against insulin resistance-induced dedifferentiation.

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    In the pathogenesis of type 2 diabetes, development of insulin resistance triggers an increase in pancreatic β-cell insulin secretion capacity and β-cell number. Failure of this compensatory mechanism is caused by a dedifferentiation of β-cells, which leads to insufficient insulin secretion and diabetic hyperglycemia. The β-cell factors that normally protect against dedifferentiation remain poorly defined. Here, through a systems biology approach, we identify the transcription factor Klf6 as a regulator of β-cell adaptation to metabolic stress. We used a β-cell specific Klf6 knockout mouse model to investigate whether Klf6 may be a potential regulator of β-cell adaptation to a metabolic stress. We show that inactivation of Klf6 in β-cells blunts their proliferation induced by the insulin resistance of pregnancy, high-fat high-sucrose feeding, and insulin receptor antagonism. Transcriptomic analysis showed that Klf6 controls the expression of β-cell proliferation genes and, in the presence of insulin resistance, it prevents the down-expression of genes controlling mature β-cell identity and the induction of disallowed genes that impair insulin secretion. Its expression also limits the transdifferentiation of β-cells into α-cells. Our study identifies a new transcription factor that protects β-cells against dedifferentiation, and which may be targeted to prevent diabetes development

    A versatile cryogenic system for liquid argon detectors

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    Detectors for direct dark matter search using noble gases in liquid phase as detection medium need to be coupled to liquefaction, purification and recirculation systems. A dedicated cryogenic system has been assembled and operated at the INFN-Naples cryogenic laboratory with the aim to liquefy and purify the argon used as active target in liquid argon detectors to study the scintillation and ionization signals detected by large SiPMs arrays. The cryogenic system is mainly composed of a double wall cryostat hosting the detector, a purification stage to reduce the impurities below one part per billion level, a condenser to liquefy the argon, a recirculation gas panel connected to the cryostat equipped with a custom gas pump. The main features of the cryogenic system are reported as well as the performances, long term operations and stability in terms of the most relevant thermodynamic parameters.Comment: Prepared for submission to JINST - LIDINE2022 September 21-23, 2022 - University of Warsaw Librar

    World Antimalarial Resistance Network (WARN) II: In vitro antimalarial drug susceptibility

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    Intrinsic resistance of Plasmodium falciparum is clearly a major determinant of the clinical failure of antimalarial drugs. However, complex interactions between the host, the parasite and the drug obscure the ability to define parasite drug resistance in vivo. The in vitro antimalarial drug susceptibility assay determines ex-vivo growth of parasite in the presence of serial drug concentrations and, thus, eliminates host effects, such as drug metabolism and immunity. Although the sensitivity of the parasite to various antimalarials provided by such a test provides an important indicator of intrinsic parasite susceptibility, there are fundamental methodological issues that undermine comparison of in vitro susceptibility both between laboratories and within a single laboratory over time. A network of laboratories is proposed that will agree on the basic parameters of the in vitro test and associated measures of quality control. The aim of the network would be to establish baseline values of sensitivity to commonly used antimalarial agents from key regions of the world, and create a global database, linked to clinical, molecular and pharmacology databases, to support active surveillance to monitor temporal trends in parasite susceptibility. Such a network would facilitate the rapid detection of strains with novel antimalarial resistance profiles and investigate suitable alternative treatments with retained efficacy

    Stability Indicating High-Performance Liquid Chromatography Method for the Estimation of Artemether in Capsule Dosage Forms

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    A new simple, sensitive, precise, and accurate high-performance liquid chromatography (HPLC) method of analysis for artemether both as a bulk drug and in capsule formulations was developed and validated. The method employed mobile phase acetonitrile (ACN) and buffer in the ratio 65:35 of pH 6.5 adjusted with tryethylamine. The linear regression analysis data for the calibration plots showed good linear relationship with r2 = 0.9996 in the concentration range 250-750 μg/ml. The mean value slope and intercept were 9355.5 and −93.5, respectively. The method was validated for precision, accuracy, and recovery studies. Limit of detection (LOD) and Limit of quantitation (LOQ) for artemether were found to be 21.83-750 μg/ml, respectively. The method has been successfully applied in the analysis of marketed capsule formulations. The presented method was found to be reliable to separate all the degradents from all the stress conditions with resolution of more than 1.5 showing that it is a stability indicating method
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