2,173 research outputs found

    The Burr XII-Burr XII Distribution: Mathematical Properties and Characterizations

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    We introduce a new continuous distribution called the Burr XII-Burr XII distribution. Some of its properties are derived. The method of maximum likelihood is used to estimate the unknown parameters. An application is provided with details to illustrate the importance of the new. The new model provides adequate fits as compared to other related models with smallest values for A-IC, B-IC, CA-IC and HQ-IC. Characterization results are presented based on two truncated moments, hazard function as well as based on the conditional expectation

    Groundwater Vulnerability Assessment Using Different Overlay and Index Methods for Quaternary Aquifer of Wadi El-Tumilat, East Delta, Egypt

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    Contamination from rapid urban development, industrialization and agricultural sources increasingly threatens the groundwater resource in the shallow phreatic Quaternary Aquifer of the Wadi El-Tumilat (QAWT), East Delta, Egypt. In this paper, fourteen environmental sensitive heavy metals and two minor elements (PO4-- and NO3-) were checked by the chemical analysis of both 25 surface and groundwater samples at 2006. An assessment of the QAWT intrinsic vulnerability was carried out in this paper based on GOD, PRAST and DRASTIC methods. The calculated vulnerability indexes resulted from the three methods showed great differences due to the different criterions used. Moreover, a weight modification was assumed to adequate the arid zone. The obtained QAWT vulnerability maps showed the high extension of medium vulnerability zones. The high vulnerability zones occupied about 35% and 31% from applying PRAST and DRASTIC methods respectively. The high vulnerability in these areas was mainly related to the low values of depth to water (less than 10 m), the high permeability of the soils (9 m/day) and the high permeability of the vadose zone materials (more than 11 m/day). The most suitable areas for new reclamation activity were located in the southern boundary of Wadi El Tumilat especially the strip south El Mahsama drain by 5 km. These resulted maps may provide planners with tools for a preliminary selection of priority areas for different forms of sustainable development

    Scanning tunneling spectroscopy characterization of the pseudogap and the x = 1/8 anomaly in La2-xSrxCuO4 thin films

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    Using scanning tunneling spectroscopy we examined the local density of states of thin c-axis La2-xSrxCuO4 films, over wide doping and temperature ranges. We found that the pseudogap exists only at doping levels lower than optimal. For x = 0.12, close to the 'anomalous' x = 1/8 doping level, a zero bias conductance peak was the dominant spectral feature, instead of the excepted V- shaped (c-axis tunneling) gap structure. We have established that this surprising effect cannot be explained by tunneling into (110) facets. Possible origins for this unique behavior are discussed.Comment: 15 pages, 6 figure

    Effect of fiber orientation on shape and stability of air-water interface on submerged superhydrophobic electrospun thin coatings

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    To better understand the role of fiber orientation on the stability of superhydrophobicelectrospun coatings under hydrostaticpressures, an integro-differential equation is developed from the balance of forces across the air–water interface between the fibers. This equation is solved numerically for a series of superhydrophobicelectrospun coatings comprised of random and orthogonal fiber orientations to obtain the exact 3D shape of the air–water interface as a function of hydrostaticpressure. More important, this information is used to predict the pressure at which the coatings start to transition from the Cassie state to the Wenzel state, i.e., the so-called critical transition pressure. Our results indicate that coatings composed of orthogonal fibers can withstand higher elevated hydrostaticpressures than those made up of randomly orientated fibers. Our results also prove that thin superhydrophobic coatings can better resist the elevated pressures. The modeling methodology presented here can be used to design nanofibrous superhydrophobic coatings for underwater applications

    High dose intravenous immunoglobulin in Rh and ABO hemolytic disease of Egyptian neonates

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    Background: Despite advances made in the use of phototherapy, and in order to avoid sequelae of kernicterus, the treatment of hyperbilirubinemia may require one or several exchange transfusions, an invasive therapy which is not without risk. Intravenous immune globulin treatment in isoimmune hyperbilirubinemia has been shown to be effective, but the response to treatment is variable. Objective: To evaluate effectiveness of high dose Intravenous immune globulin (HD-IVIG) in reducing the need for exchange transfusion, duration of phototherapy and/or hospitalization in neonates with isoimmune hemolytic disease due to Rh or ABO incompatibility. Methods: The study included 116 direct Coombs' test positive neonates delivered at Gynecology and Obstetrics Hospital of Ain Shams University, Cairo, Egypt. They were randomly assigned to receive phototherapy with HD-IVIG in a single dose of 1 gm/kg (60 neonates, intervention group) or phototherapy (56 neonates, control group). Results: Nine neonates in the intervention group (15%) and 23 (41%) in the control group required single exchange transfusion (p< 0.001). Multiple exchange transfusion was indicated in 15 neonates (26.8%) in the control group versus none in the intervention group (p< 0.001). Compared with control group, neonates in the intervention group had shorter mean duration of intensive phototherapy (9.97 versus 35.5 hours, p<0.001) and hospital stay (27.9 versus 103.5 hours, p< 0.001). No adverse effects of HD-IVIG administration were noted. Conclusion: HD-IVIG effectively reduced the requirement for exchange transfusion and duration of phototherapy and hospitalization in isoimmune hemolytic disease of the newborn.Keywords: Hemolytic disease of newborn; hyperbilirubinemia; exchange transfusion; high dose intravenous immunoglobulin

    Novel Approaches towards Highly Selective Self-Powered Gas Sensors

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    The prevailing design approaches of semiconductor gas sensors struggle to overcome most of their current limitations such as poor selectivity, and high power consumption. Herein, a new sensing concept based on devices that are capable of detecting gases without the need of any external power sources required to activate interaction of gases with sensor or to generate the sensor read out signal. Based on the integration of complementary functionalities (namely; powering and sensing) in a singular nanostructure, self-sustained gas sensors will be demonstrated. Moreover, a rational methodology to design organic surface functionalization that provide high selectivity towards single gas species will also be discussed. Specifically, theoretical results, confirmed experimentally, indicate that precisely tuning of the sterical and electronic structure of sensor material/organic interfaces can lead to unprecedented selectivity values, comparable to those typical of bioselective processes. Finally, an integrated gas sensor that combine both the self-powering and selective detection strategies in one single device will also be presented. © 2015 Published by Elsevier Ltd.Peer ReviewedPostprint (published version

    Acute neuromodulation restores spinally-induced motor responses after severe spinal cord injury

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    Epidural electrical spinal stimulation can facilitate recovery of volitional motor control in individuals that have been completely paralyzed for more than a year. We recently reported a novel neuromodulation method named Dynamic Stimulation (DS), which short-lastingly increased spinal excitability and generated a robust modulation of locomotor networks in fully-anesthetized intact adult rats. In the present study, we applied repetitive DS patterns to four lumbosacral segments acutely after a contusive injury at lumbar level. Repetitive DS delivery restored the spinally-evoked motor EMG responses that were previously suppressed by a calibrated spinal cord contusion. Sham experiments without DS delivery did not allow any spontaneous recovery. Thus, DS uniquely provides the potential for a greater long-term functional recovery after paralysis

    GEVALT: An integrated software tool for genotype analysis

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    BACKGROUND: Genotype information generated by individual and international efforts carries the promise of revolutionizing disease studies and the association of phenotypes with alleles and haplotypes. Given the enormous amounts of public genotype data, tools for analyzing, interpreting and visualizing these data sets are of critical importance to researchers. In past works we have developed algorithms for genotypes phasing and tag SNP selection, which were shown to be quick and accurate. Both algorithms were available until now only as batch executables. RESULTS: Here we present GEVALT (GEnotype Visualization and ALgorithmic Tool), a software package designed to simplify and expedite the process of genotype analysis, by providing a common interface to several tasks relating to such analysis. GEVALT combines the strong visual abilities of Haploview with our quick and powerful algorithms for genotypes phasing (GERBIL), tag SNP selection (STAMPA) and permutation testing for evaluating significance of association. All of the above are provided in a visually appealing and interactive interface. CONCLUSION: GEVALT is an integrated viewer that uses state of the art phasing and tag SNP selection algorithms. By streamlining the application of GERBIL and STAMPA together with strong visualization for assessment of the results, GEVALT makes the algorithms accessible to the broad community of researchers in genetics

    The Energy of Regular Black Hole in General Relativity Coupled to Nonlinear Electrodynamics

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    According to the Einstein, Weinberg, and M{\o}ller energy-momentum complexes, we evaluate the energy distribution of the singularity-free solution of the Einstein field equations coupled to a suitable nonlinear electrodynamics suggested by Ay\'{o}n-Beato and Garc\'{i}a. The results show that the energy associated with the definitions of Einstein and Weinberg are the same, but M{\o}ller not. Using the power series expansion, we find out that the first two terms in the expression are the same as the energy distributions of the Reissner-Nordstr\"{o}m solution, and the third term could be used to survey the factualness between numerous solutions of the Einstein field eqautions coupled to a nonlinear electrodynamics.Comment: 11 page
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