Drexel University

About: Drexel University is a education organization based out in Philadelphia, Pennsylvania, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 26770 authors who have published 51438 publications receiving 1949443 citations. The organization is also known as: Drexel & Drexel Institute.

One-Dimensional Composite Nanomaterials: Synthesis by Electrospinning and Their Applications

Abstract: This Review provides an overview of the synthesis of one-dimensional (1D) composite nanomaterials by electrospinning and their applications. After a brief description of the development of the electrospinning technique, the transformation of an inorganic nanocomponent or polymer into another kind of polymer or inorganic matrix is discussed in terms of the electrospinning process, including the direct-dispersed method, gas-solid reaction, in situ photoreduction, sol-gel method, emulsion electrospinning method, solvent evaporation, and coaxial electrospinning. In addition, various applications of such 1D composite nanomaterials are highlighted in terms of electronic and optical nanodevices, chemical and biological sensors, catalysis and electrocatalysis, superhydrophobic surfaces, environment, energy, and biomedical fields. An increasing number of investigations show that electrospinning has been not only a focus of academic study in the laboratory but is also being applied in a great many technological fields.

An organization-level analysis of voluntary and involuntary turnover.

Abstract: Although there are many individual-level models of turnover, little research has examined the effects of human resource management practices on quit rates and discharge rates at the organizational level. This study used organization-level data from 227 organizations in the trucking industry to explore this issue. Results show that human resource management practices predict quit rates and discharge rates but that the determinants of each are quite different. Implications are derived and directions for future research suggested.

The Broadband Optical Properties of Galaxies with Redshifts 0.02 < z < 0.22

Abstract: Using photometry and spectroscopy of 183,487 galaxies from the Sloan Digital Sky Survey, we present bivariate distributions of pairs of seven galaxy properties: four optical colors, surface brightness, radial profile shape as measured by the Sersic index, and absolute magnitude. In addition, we present the dependence of local galaxy density (smoothed on 8 h � 1 Mpc scales) on all of these properties. Several classic, well-known relations among galaxy properties are evident at extremely high signal-to-noise ratio: the color- color relations of galaxies, the color-magnitude relations, the magnitude-surface brightness relation, and the dependence of density on color and absolute magnitude. We show that most of the i-band luminosity density in the universe is in the absolute magnitude and surface brightness ranges used: � 23:5 < M0:1i < � 17:0 mag and 17 < l0:1i < 24 mag in 1 arcsec 2 (the notation z b represents the b band shifted blueward by a factor ð1 þ zÞ). Some of the relationships between parameters, in particular the color-magnitude relations, show stronger correlations for exponential galaxies and concentrated galaxies taken separately than for all galaxies taken together. We provide a simple set of fits of the dependence of galaxy properties on luminosity for these two sets of galaxies and other quantitative details of our results. Subject headings: galaxies: fundamental parameters — galaxies: photometry — galaxies: statistics On-line material: ASCII parameter files, color figure, FITS files 1. MOTIVATION There are strong correlations among the measurable physical properties of galaxies. The classification of galaxies along the visual morphological sequence described by Hubble (1936) correlates well with the dominance of their central bulge, their surface brightnesses, and their colors. These properties also correlate with other properties, such as metallicity, emission-line strength, luminosity in visual bands, neutral gas content, and the winding angle of the spiral structure (for a review, see Roberts & Haynes 1994). The surface brightnesses of giant galaxies classified morpho- logically as elliptical are known to be strongly correlated with their sizes (Kormendy 1977; Kormendy & Djorgovski 1989). Galaxy colors (at least of morphologically elliptical galaxies) are known to be strongly correlated with galaxy luminosity (Baum 1959; Faber 1973; Visvanathan & Sandage 1977; Terlevich et al. 2001). The gravitational mass of a galaxy is closely related to the luminosity and other galaxy properties. These galaxy relations manifest them-

The Effects of Low-Carbohydrate versus Conventional Weight Loss Diets in Severely Obese Adults: One-Year Follow-up of a Randomized Trial

Abstract: Participants on a low-carbohydrate diet had better results overall at 1 year than those on a low-fat, restricted-calorie diet Weight loss was the same in the 2 groups, but patients on the low-carb