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

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

Anomalous proximity effect in gold coated (110) YBa2Cu3O7−δYBa_2Cu_3O_{7-\delta} films: Penetration of the Andreev bound states

Scanning tunneling spectroscopy of (110) $YBa_2Cu_3O_{7-\delta}/Au$ bi-layers reveal a proximity effect markedly different from the conventional one. While proximity-induced mini-gaps rarely appear in the Au layer, the Andreev bound states clearly penetrate into the metal. Zero bias conductance peaks are measured on Au layers thinner than 7 nm with magnitude similar to those detected on the bare superconductor films. The peaks then decay abruptly with Au thickness and disappear above 10 nm. This length is shorter than the normal coherence length and corresponds to the (ballistic) mean free path.Comment: 5 prl format pages, 4 figures, to be published in PR

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

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

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

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

And yet it moves: Recovery of volitional control after spinal cord injury

Preclinical and clinical neurophysiological and neurorehabilitation research has generated rather surprising levels of recovery of volitional sensory-motor function in persons with chronic motor paralysis following a spinal cord injury. The key factor in this recovery is largely activity-dependent plasticity of spinal and supraspinal networks. This key factor can be triggered by neuromodulation of these networks with electrical and pharmacological interventions. This review addresses some of the systems-level physiological mechanisms that might explain the effects of electrical modulation and how repetitive training facilitates the recovery of volitional motor control. In particular, we substantiate the hypotheses that: (1) in the majority of spinal lesions, a critical number and type of neurons in the region of the injury survive, but cannot conduct action potentials, and thus are electrically non-responsive; (2) these neuronal networks within the lesioned area can be neuromodulated to a transformed state of electrical competency; (3) these two factors enable the potential for extensive activity-dependent reorganization of neuronal networks in the spinal cord and brain, and (4) propriospinal networks play a critical role in driving this activity-dependent reorganization after injury. Real-time proprioceptive input to spinal networks provides the template for reorganization of spinal networks that play a leading role in the level of coordination of motor pools required to perform a given functional task. Repetitive exposure of multi-segmental sensory-motor networks to the dynamics of task-specific sensory input as occurs with repetitive training can functionally reshape spinal and supraspinal connectivity thus re-enabling one to perform complex motor tasks, even years post injury

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

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

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

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

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

Enhancement of the superconducting transition temperature in La2-xSrxCuO4 bilayers: Role of pairing and phase stiffness

The superconducting transition temperature, Tc, of bilayers comprising underdoped La2-xSrxCuO4 films capped by a thin heavily overdoped metallic La1.65Sr0.35CuO4 layer, is found to increase with respect to Tc of the bare underdoped films. The highest Tc is achieved for x = 0.12, close to the 'anomalous' 1/8 doping level, and exceeds that of the optimally-doped bare film. Our data suggest that the enhanced superconductivity is confined to the interface between the layers. We attribute the effect to a combination of the high pairing scale in the underdoped layer with an enhanced phase stiffness induced by the overdoped film.Comment: Published versio