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.

The shape of the sloan digital sky survey data release 5 galaxy power spectrum

Abstract: We present a Fourier analysis of the clustering of galaxies in the combined main galaxy and LRG SDSS DR5 sample. The aim of our analysis is to consider how well we can measure the cosmological matter density using the signature of the horizon at matter-radiation equality embedded in the large-scale power spectrum. The new data constrain the power spectrum on scales 100-600 h-1 Mpc with significantly higher precision than previous analyses of just the SDSS main galaxies, due to our larger sample and the inclusion of the LRGs. This improvement means that we can now reveal a discrepancy between the shape of the measured power and linear CDM models on scales 0.01 h Mpc-1 < k < 0.15 h Mpc-1, with linear model fits favoring a lower matter density (ΩM = 0.22 ± 0.04) on scales 0.01 h Mpc-1 < k < 0.06 h Mpc-1 and a higher matter density (ΩM = 0.32 ± 0.01) when smaller scales are included, assuming a flat ΛCDM model with h = 0.73 and ns = 0.96. This discrepancy could be explained by scale-dependent bias, and by analyzing subsamples of galaxies, we find that the ratio of small-scale to large-scale power increases with galaxy luminosity, so all of the SDSS galaxies cannot trace the same power spectrum shape over 0.01 h Mpc-1 < k < 0.2 h Mpc-1. However, the data are insufficient to clearly show a luminosity-dependent change in the largest scale at which a significant increase in clustering is observed, although they do not rule out such an effect. Significant scale-dependent galaxy bias on large scales, which changes with the r-band luminosity of the galaxies, could potentially explain differences in our ΩM estimates and differences previously observed between 2dFGRS and SDSS power spectra and the resulting parameter constraints.

The psychiatric symptoms of Alzheimer's disease.

Abstract: The authors used a semistructured interview administered to primary family caregivers to assess the prevalence and nature of psychiatric pathology in 175 well-diagnosed community-residing Alzheimer's disease patients. Symptoms that are indicative of depression in the cognitively intact were virtually ubiquitous in this demented population. A variety of psychotic features were also regularly reported. The implications of these findings for the recognition and treatment of reversible psychiatric impairment are discussed.

Nanodiamond-Polymer Composite Fibers and Coatings

Abstract: While nanocrystalline diamond is quickly becoming one of the most widely studied nanomaterials, achieving a large fraction of diamond nanoparticles in a polymer coating has been an unresolved problem. In this work, polymer nano- and microfibers containing high loadings of 5 nm diamond particles (up to 80 wt % in polyacrylonitrile and 40% in polyamide 11) have been demonstrated using electrospun nanofibers as a delivery vehicle. The electrospun nanofibers with a high load of nanodiamond in the polymers were fused into thin transparent films, which had high mechanical properties; an improvement of 4 times for the Young's modulus and 2 times for the hardness was observed already at 20% nanodiamond in polyamide 11. These films can provide UV protection and scratch resistance to a variety of surfaces, especially in applications where a combination of mechanical, thermal, and dielectric properties is required.

Mining comparative opinions from customer reviews for Competitive Intelligence

Abstract: Competitive Intelligence is one of the key factors for enterprise risk management and decision support. However, the functions of Competitive Intelligence are often greatly restricted by the lack of sufficient information sources about the competitors. With the emergence of Web 2.0, the large numbers of customer-generated product reviews often contain information about competitors and have become a new source of mining Competitive Intelligence. In this study, we proposed a novel graphical model to extract and visualize comparative relations between products from customer reviews, with the interdependencies among relations taken into consideration, to help enterprises discover potential risks and further design new products and marketing strategies. Our experiments on a corpus of Amazon customer reviews show that our proposed method can extract comparative relations more accurately than the benchmark methods. Furthermore, this study opens a door to analyzing the rich consumer-generated data for enterprise risk management.

Post-Traumatic Stress Disorder in Sexually Abused Children

Abstract: Thirty-one sexually abused children were studied using structured interviews and standardized instruments to determine the frequency of post-traumatic stress disorder (PTSD) and associated symptoms. Of these sexually abused children, 48.4% met DSM-III-R PTSD criteria; 75% of children abused by natural fathers, 67% abused by strangers, and 25% of those abused by trusted adults met criteria as opposed to none of the children abused by an older child. Many children not meeting full DSM-III-R criteria exhibited partial PTSD symptoms. No relationship was observed between the time lapsed since last abusive episode and the development of PTSD. Three standardized instruments (CDI, SEI, and STAIC), although useful in identifying non-PTSD related symptoms, were not useful in differentiating PTSD. The CBCL detected group differences, with PTSD children exhibiting significantly more symptoms of externalizing and internalizing behaviors.