Non-parametric Reconstruction of Cluster Mass Distribution from Strong Lensing: Modelling Abell 370

We describe a new non-parametric technique for reconstructing the mass distribution in galaxy clusters with strong lensing, i.e., from multiple images of background galaxies. The observed positions and redshifts of the images are considered as rigid constraints and through the lens (ray-trace) equation they provide us with linear constraint equations. These constraints confine the mass distribution to some allowed region, which is then found by linear programming. Within this allowed region we study in detail the mass distribution with minimum mass-to-light variation; also some others, such as the smoothest mass distribution. The method is applied to the extensively studied cluster Abell 370, which hosts a giant luminous arc and several other multiply imaged background galaxies. Our mass maps are constrained by the observed positions and redshifts (spectroscopic or model-inferred by previous authors) of the giant arc and multiple image systems. The reconstructed maps obtained for \a370 reveal a detailed mass distribution, with substructure quite different from the light distribution. The method predicts the bimodal nature of the cluster and that the projected mass distribution is indeed elongated along the axis defined by the two dominant cD galaxies. But the peaks in the mass distribution appear to be offset from the centres of the cDs. We also present an estimate for the total mass of the central region of the cluster. This is in good agreement with previous mass determinations. The total mass of the central region is M=(2.0-2.7) 10^14 Msun/h50, depending on the solution chosen.Comment: 14 pages(19 postscript figures), minor corrections, MNRAS in pres

Electro-absorption of silicene and bilayer graphene quantum dots

We study numerically the optical properties of low-buckled silicene and AB-stacked bilayer graphene quantum dots subjected to an external electric field, which is normal to their surface. Within the tight-binding model, the optical absorption is calculated for quantum dots, of triangular and hexagonal shapes, with zigzag and armchair edge terminations. We show that in triangular silicene clusters with zigzag edges a rich and widely tunable infrared absorption peak structure originates from transitions involving zero energy states. The edge of absorption in silicene quantum dots undergoes red shift in the external electric field for triangular clusters, whereas blue shift takes place for hexagonal ones. In small clusters of bilayer graphene with zigzag edges the edge of absorption undergoes blue/red shift for triangular/hexagonal geometry. In armchair clusters of silicene blue shift of the absorption edge takes place for both cluster shapes, while red shift is inherent for both shapes of the bilayer graphene quantum dots.Comment: 7 pages, 7 figure

Integrated DPSIR-ANP-SD framework for Sustainability Assessment of Water Resources System in Egypt

Abstract: Nowadays fresh water severe scarcity is a global concern and it is alarming for the future. In order to fully understand the progress of the water system and its impacts, a sustainability assessment of water resources is needed. This accelerates the achievement of sustainability and management of water resources. This work aims to assess the sustainability of the water resources system by applying the integration approach proposed by (Xu, 2011). This integration approach is based on integrating the DPSIR-ANP method to the System Dynamics (SD) model, which is considered as a unique work in water resources management field. SD is a computer simulation model to understanding the behavior of complex systems over time, while Analytic Network Process (ANP) is a decision finding method used in model complex decision problems which contains feedback connections and loops. DPSIR is an analytical framework for describing the interactions between the economy, society and the environment. This integrated approach enables decision makers to view the sustainability problems of water resources system more comprehensively. The results showed that there is an increasing impact on the sustainability of water resources systems in Egypt over the research period. This is attributed to the increase in water resources consumption due to the increase in population, agriculture expansion and an increase in the value of GDP. So, the officials for managing water resources in Egypt should take actions to increase the efficiency of water use and increasing the renewable water resources for compensating water shortage

Life Adaptation Program & Its Effect on Daily Living Skills of Autistic Children and Their Parents Stress

This study aimed to investigate the effect of life adaptation program on daily living skills (DLS) of autistic children and their parent's stress. A quasi -experimental design was utilized in this study. A purposive sample of thirty autistic children and their parents were recruited from Autism Day Care Unit-Beit El-shams- Child Psychiatry Clinic in El-Abbassia Mental Health Hospital. Three tools were used to conduct the current study, sociodemographic and medical data sheet, autistic child skills scale, and parent's stress scale. The results showed that, more than eighty percent of the studied children had low level of daily living skills, and slightly more than half of the studied parents had moderate stress level. Findings revealed that there was a highly statistically significant difference between pre-post program regarding daily living skills & there was a highly statistically significant difference between parents stress pre and post program. In conclusion, early intervention play significant role in the development of DLS of all ages, yet further researches are needed for developing and maintenance of DLS of autistic children. Keywords: autistic disorder, daily living skills, parents stress

Non-parametric mass reconstruction of A1689 from strong lensing data with SLAP

We present the mass distribution in the central area of the cluster A1689 by fitting over 100 multiply lensed images with the non-parametric Strong Lensing Analysis Package (SLAP, Diego et al. 2004). The surface mass distribution is obtained in a robust way finding a total mass of 0.25E15 M_sun/h within a 70'' circle radius from the central peak. Our reconstructed density profile fits well an NFW profile with small perturbations due to substructure and is compatible with the more model dependent analysis of Broadhurst et al. (2004a) based on the same data. Our estimated mass does not rely on any prior information about the distribution of dark matter in the cluster. The peak of the mass distribution falls very close to the central cD and there is substructure near the center suggesting that the cluster is not fully relaxed. We also examine the effect on the recovered mass when we include the uncertainties in the redshift of the sources and in the original shape of the sources. Using simulations designed to mimic the data, we identify some biases in our reconstructed mass distribution. We find that the recovered mass is biased toward lower masses beyond 1 arcmin (150 kpc) from the central cD and that in the very center we may be affected by degeneracy problems. On the other hand, we confirm that the reconstructed mass between 25'' and 70'' is a robust, unbiased estimate of the true mass distribution and is compatible with an NFW profile.Comment: 11 pages, 12 figures. MNRAS submitted. A full resolution of the paper can be found in http://darwin.physics.upenn.edu/SLAP

A new active power controller in dual active bridge DC-DC converter with a minimum-current-point-tracking technique

This article proposes a new controller for power regulation in dual active bridge (DAB) dc-dc converter based on a new scheme that tracks minimum RMS current to ensure minimum losses. The proposed controller is based on an implementation of perturb and observe (PO) tracking method that enables minimum current point tracking (MCPT) at any desired level of active power transfer and dc voltage ratio. The PO is embedded in a closed-loop control scheme which simultaneously regulates active power in DAB converter. The nonlinear I - V characteristic of DAB presents the basis for this proposed controller and the rationale of using PO algorithm. The proposed controller does not require complex nonlinear converter modeling and is not circuit parameter dependent. Design procedure of the proposed controller is presented, and extensive simulation is carried out using MATLAB/Simulink to validate the effectiveness of the proposed MCPT closed-loop controller. An experimental prototype also substantiates the results achieved

Shape-induced anisotropy in antidot arrays from self-assembled templates

Using self-assembly of polystyrene spheres, well-ordered templates have been prepared on glass and silicon substrates. Strong guiding of self-assembly is obtained on photolithographically structured silicon substrates. Magnetic antidot arrays with three-dimensional architecture have been prepared by electrodeposition in the pores of these templates. The shape anisotropy demonstrates a crucial impact on magnetization reversal processes

Análisis de la interacción ventrículo-valvulo-arterial en pacientes con estenosis aórtica

La estenosis aórtica es probablemente la valvulopatía más importante en el mundo occidental, debido a su alta prevalencia y al grave impacto que tiene sobre la calidad y esperanza de vida de las personas que la padecen, de modo que la supervivencia en los pacientes sintomáticos es de aproximadamente un 50% a dos años. Durante décadas, la sustitución valvular quirúrgica ha sido la única opción de tratamiento con capacidad para modificar el pronóstico de la estenosis aórtica, y sin embargo, un 30% de los pacientes con estenosis aórtica severa sintomática no son operados por diversos motivos. En los últimos años, la sustitución valvular aórtica con catéter (TAVI) ha surgido como una opción de tratamiento para pacientes inoperables y de alto riesgo quirúrgico. La TAVI es superior al tratamiento farmacológico, reduciendo la mortalidad y mejorando los síntomas; además, en pacientes de alto riesgo quirúrgico, la TAVI tiene resultados al menos tan buenos como la cirugía. En la última década se ha producido un gran avance en los dispositivos y técnicas disponibles para TAVI, lo que ha contribuido a mejorar los resultados y reducir las complicaciones. La oposición al flujo sistólico en la estenosis aórtica viene determinada por la suma de la obstrucción valvular y la carga vascular. Esta última a menudo se encuentra anormalmente alta en la estenosis aórtica, debido a la hipertensión arterial y a la alta prevalencia de enfermedad vascular sistémica que presentan estos pacientes, lo que contribuye de forma importante a la postcarga total del ventrículo izquierdo. Además, entre la obstrucción valvular y la carga vascular existe un fenómeno de interdependencia, de forma que al reducir uno de los componentes aumenta el otro, y a la inversa..

Metachronal propulsion of a magnetized particle-fluid suspension in a ciliated channel with heat and mass transfer

Biologically inspired pumping systems are of great interest in modern engineering since they achieve enhanced efficiency and circumvent the need for moving parts and maintenance. Industrial applications also often feature two-phase flows. In this article, motivated by these applications, the pumping of an electrically conducting particle-fluid suspension due to metachronal wave propulsion of beating cilia in a two-dimensional channel with heat and mass transfer under a transverse magnetic field is investigated theoretically. The governing equations for mass and momentum conservation for fluid- and particle-phases are formulated by ignoring the inertial forces and invoking the long wavelength approximation. The Jeffrey viscoelastic model is employed to simulate non-Newtonian characteristics. The normalized resulting differential equations are solved analytically. Symbolic software is employed to evaluate the results and simulate the influence of different parameters on flow characteristics. Results are visualized graphically with carefully selected and viable data