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 fourth data release of the Sloan Digital Sky Survey

Abstract: This paper describes the Fourth Data Release of the Sloan Digital Sky Survey (SDSS), including all survey-quality data taken through 2004 June. The data release includes five-band photometric data for 180 million objects selected over 6670 deg2 and 673,280 spectra of galaxies, quasars, and stars selected from 4783 deg2 of those imaging data using the standard SDSS target selection algorithms. These numbers represent a roughly 27% increment over those of the Third Data Release; all the data from previous data releases are included in the present release. The Fourth Data Release also includes an additional 131,840 spectra of objects selected using a variety of alternative algorithms, to address scientific issues ranging from the kinematics of stars in the Milky Way thick disk to populations of faint galaxies and quasars.

Author cocitation: A literature measure of intellectual structure

Abstract: It is shown that the mapping of a particular area of science, in this case information science, can be done using authors as units of analysis and the cocitations of pairs of authors as the variable that indicates their “distances” from each other. The analysis assumes that the more two authors are cited together, the closer the relationship between them. The raw data are cocitation counts drawn online from Social Scisearch (Social Sciences Citation Index) over the period 1972–1979. The resulting map shows (1) identifiable author groups (akin to “schools”) of information science, (2) locations of these groups with respect to each other, (3) the degree of centrality and peripherality of authors within groups, (4) proximities of authors within group and across group boundaries (“border authors” who seem to connect various areas of research), and (5) positions of authors with respect to the map's axes, which were arbitrarily set spanning the most divergent groups in order to aid interpretation. Cocitation analysis of authors offers a new technique that might contribute to the understanding of intellectual structure in the sciences and possibly in other areas to the extent that those areas rely on serial publications. The technique establishes authors, as well as documents, as an effective unit in analyzing subject specialties.

Staphylococcus aureus Endocarditis A Consequence of Medical Progress

Abstract: ContextThe global significance of infective endocarditis (IE) caused by Staphylococcus aureus is unknown.ObjectivesTo document the international emergence of health care–associated S aureus IE and methicillin-resistant S aureus (MRSA) IE and to evaluate regional variation in patients with S aureus IE.Design, Setting, and ParticipantsProspective observational cohort study set in 39 medical centers in 16 countries. Participants were a population of 1779 patients with definite IE as defined by Duke criteria who were enrolled in the International Collaboration on Endocarditis-Prospective Cohort Study from June 2000 to December 2003.Main Outcome MeasureIn-hospital mortality.ResultsS aureus was the most common pathogen among the 1779 cases of definite IE in the International Collaboration on Endocarditis Prospective-Cohort Study (558 patients, 31.4%). Health care−associated infection was the most common form of S aureus IE (218 patients, 39.1%), accounting for 25.9% (Australia/New Zealand) to 54.2% (Brazil) of cases. Most patients with health care−associated S aureus IE (131 patients, 60.1%) acquired the infection outside of the hospital. MRSA IE was more common in the United States (37.2%) and Brazil (37.5%) than in Europe/Middle East (23.7%) and Australia/New Zealand (15.5%, P<.001). Persistent bacteremia was independently associated with MRSA IE (odds ratio, 6.2; 95% confidence interval, 2.9-13.2). Patients in the United States were most likely to be hemodialysis dependent, to have diabetes, to have a presumed intravascular device source, to receive vancomycin, to be infected with MRSA, and to have persistent bacteremia (P<.001 for all comparisons).ConclusionsS aureus is the leading cause of IE in many regions of the world. Characteristics of patients with S aureus IE vary significantly by region. Further studies are required to determine the causes of regional variation.

The Second Data Release of the Sloan Digital Sky Survey

Abstract: The Sloan Digital Sky Survey (SDSS) has validated and made publicly available its Second Data Release. This data release consists of 3324 deg2 of five-band (ugriz) imaging data with photometry for over 88 million unique objects, 367,360 spectra of galaxies, quasars, stars, and calibrating blank sky patches selected over 2627 deg2 of this area, and tables of measured parameters from these data. The imaging data reach a depth of r ≈ 22.2 (95% completeness limit for point sources) and are photometrically and astrometrically calibrated to 2% rms and 100 mas rms per coordinate, respectively. The imaging data have all been processed through a new version of the SDSS imaging pipeline, in which the most important improvement since the last data release is fixing an error in the model fits to each object. The result is that model magnitudes are now a good proxy for point-spread function magnitudes for point sources, and Petrosian magnitudes for extended sources. The spectroscopy extends from 3800 to 9200 A at a resolution of 2000. The spectroscopic software now repairs a systematic error in the radial velocities of certain types of stars and has substantially improved spectrophotometry. All data included in the SDSS Early Data Release and First Data Release are reprocessed with the improved pipelines and included in the Second Data Release. Further characteristics of the data are described, as are the data products themselves and the tools for accessing them.

Comprehensive QA for radiation oncology: report of AAPM Radiation Therapy Committee Task Group 40.

Abstract: Published by the American Association of Physicists in Medicine DISCLAIMER: This publication is based on sources and information believed to be reliable, but the AAPM and the editors disclaim any warranty or liability based on or relating to the contents of this publication. The AAPM does not endorse any products, manufacturers, or suppliers. Nothing in this publication should be interpreted as implying such endorsement. PREFACE This document is the report of a task group of the Radiation Therapy Committee of the American Association of Physicists in Medicine and supersedes the recommendations of AAPM Report 13 (AAPM, 1984). The purpose of the report is twofold. First, the advances in radiation oncology in the decade since AAPM Report 13 (AAPM, 1984) necessitated a new document on quality assurance (QA). Second, developments in the principles of quality assurance and continuing quality improvement necessitated a report framed in this context. The title \" Comprehensive Quality Assurance for Radiation Oncology \" may need clarification. While the report emphasizes the physical aspects of QA and does not attempt to discuss issues that are essentially medical (e.g., the decision to treat, the prescription of dose), it by no means neglects issues in which the physical and medical issues intertwine, often in a complex manner. The integrated nature of QA in radiation oncology makes it impossible to consider QA as limited to, for example, checking machine output or calibrating brachytherapy sources. QA activities cover a very broad range, and the work of medical physicists in this regard extends into a number of areas in which the actions of radiation oncologists, radiation therapists, 1 dosimetrists, accelerator engineers, and medical physicists are important. Moreover, this is true for each of the disciplines-each has special knowledge and expertise which affects the quality of treatment , and each discipline overlaps the others in a broad \" gray zone. \" It is important not only to understand each discipline's role in QA, but to clarify this zone so that errors do not \" fall between the cracks. \" This report therefore attempts to cover the physical aspects of QA both in a narrow or traditional sense and in a more integrated sense. The report comprises 2 parts: Part A is for administrators, and Part B is a code of practice in six sections. The first section of Part B describes a comprehensive quality assurance program in which the importance of a written procedural …