3,741 research outputs found

    The McNeil Mission and the Decision to Invade Grenada

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    Since the invasion of Grenada in October 1983 numerous scholars have explored the military, legal, and geopolitical dimensions of Operation Urgent Fury

    Non-Gaussian features of primordial magnetic fields in power-law inflation

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    We show that a conformal-invariance violating coupling of the inflaton to electromagnetism produces a cross correlation between curvature fluctuations and a spectrum of primordial magnetic fields. According to this model, in the case of power-law inflation, a primordial magnetic field is generated with a nearly flat power spectrum and rms amplitude ranging from nG to pG. We study the cross correlation, a three-point function of the curvature perturbation and two powers of the magnetic field, in real and momentum space. The cross-correlation coefficient, a dimensionless ratio of the three-point function with the curvature perturbation and magnetic field power spectra, can be several orders of magnitude larger than expected as based on the amplitude of scalar metric perturbations from inflation. In momentum space, the cross-correlation peaks for flattened triangle configurations, and is three orders of magnitude larger than the squeezed triangle configuration. These results suggest likely methods for distinguishing the observational signatures of the model.Comment: 15 pages, 2 figure

    The Greatest Good for the Greatest Number: An Experimental Study of the Effects of Racial and Ethnic Diversity on Liberal Arts College Discussions

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    Abstract The study tested the Supreme Court majority opinion in the affirmative action case, Grutter v. The non-diverse classes had higher percentages of critical thinking propositions as measured by the proportional frequency of high-level arguments and text-based claims in individual turns of discussion, while diverse classes had higher percentages of opinions and claims based on personal experiences. However, students in diverse classes also joined formal claims to their opinions in 25% of turns, whereas the non-diverse classes only did so in less than 10%. While significantly different critical responses were found in both diverse and non-diverse classes, diverse classes had higher proportions of highlevel questions, re-phrasings and greater numbers of elaborations/clarifications of communications responding to previous turns. Two patterns of class discussion emerged from the research: 1) participation, inclusiveness, student interaction, and critical responsiveness may be supported by a discussion climate in which there is permission to express opinions and claims based on personal experience that afforded students relatively easy entry into discussions and 2) a climate in which text-based claims and arguments are the standard may result in a relatively small hierarchy of students capable of making such statements. A three-stage model was proposed that encouraged discussion leaders to allow students to voice opinions as a means of affording wide participation, then follow-up by encouraging students to make text-based claims and full arguments. As measured by several criteria in the diverse groups: wide and inclusive participation, high peer-to-peer interaction, greater understanding by a larger proportion of students that opinions need to be backed up with evidence, and exposure to more highlevel claims and responses; versus instructor domination, lower student participation, active critical thinking in only a limited number of students, and lower peer to peer responsiveness in the non-diverse groups, we conclude that the diverse classes provided more value --the "greatest good to the greatest number" --to their students than the non-diverse classes.

    Adenoma Characteristics at First Colonoscopy as Predictors of Adenoma Recurrence and Characteristics at Follow-Up

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    All patients with colorectal adenomas may not require identical follow-up. We aimed to determine if adenoma characteristics at initial colonoscopy could predict adenoma recurrence or characteristics at follow-up. The number of adenomas and the size, type, and degree of atypia in 479 patients in a polyp prevention trial were evaluated as predictors of the same characteristics at follow-up using odds ratios (ORs) with 95% confidence intervals (CIs). Multiple logistic regression analysis was performed to determine if several baseline characteristics were simultaneously associated with outcome

    A Comparison of Data Sources for Motor Vehicle Crash Characteristic Accuracy

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    Objective: To determine the accuracy of police reports (PRs), ambulance reports (ARs), and emergency department records (EDRs) in describing motor vehicle crash (MVC) characteristics when compared with an investigation performed by an experienced crash investigator trained in impact biomechanics. Methods: This was a cross-sectional, observational study. Ninety-one patients transported by ambulance to a university emergency department (ED) directly from the scene of an MVC from August 1997 to April 1998 were enrolled. Potential patients were identified from the ED log and consent was obtained to investigate the crash vehicle. Data describing MVC characteristics were abstracted from the PR, AR, and medical record. Variables of interest included restraint use (RU), air bag deployment (AD), and type of impact (TI). Agreements between the variables and the independent crash investigation were compared using kappa. Interrater reliability was determined using kappa by comparing a random sample of 20 abstracted reports for each data source with the originally abstracted data. Results: Agreement using kappa between the crash investigation and each data source was 0.588 (95% CI = 0.508 to 0.667) for the PR, 0.330 (95% CI = 0.252 to 0.407) for the AR, and 0.492 (95% CI = 0.413 to 0.572) for the EDR. Variable agreement was 0.239 (95% CI = 0.164 to 0.314) for RU, 0.350 (95% CI = 0.268 to 0.432) for AD, and 0.631 (95%= 0.563 to 0.698) for TI. Interrater reliability was excellent (kappa > 0.8) for all data sources. Conclusions: The strength of the agreement between the independent crash investigation and the data sources that were measured by kappa was fair to moderate, indicating inaccuracies. This presents ramifications for researchers and necessitates consideration of the validity and accuracy of crash characteristics contained in these data sources.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75653/1/j.1553-2712.2000.tb02067.x.pd

    A Successful Portable Computer Lab Training Program

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    Penn State Cooperative Extension and the Pennsylvania Farm Credit System joined forces to fund a portable computer laboratory. A simplified lab management procedure allowed Extension agents to offer 33 computer operation workshops for 300 participants at minimal participant cost. Participants indicated their future use of computers would focus on farm financial, crop, and livestock management. Although considerable competence was gained, more than 50% viewed themselves with poor to moderate computer skills at the end of the workshops. The lab has enabled agents to contact a preciously under-served population as 54% of the participants had not attended any Extension workshops in the previous year

    Integration of prostate cancer clinical data using an ontology

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    AbstractIt is increasingly important for investigators to efficiently and effectively access, interpret, and analyze the data from diverse biological, literature, and annotation sources in a unified way. The heterogeneity of biomedical data and the lack of metadata are the primary sources of the difficulty for integration, presenting major challenges to effective search and retrieval of the information. As a proof of concept, the Prostate Cancer Ontology (PCO) is created for the development of the Prostate Cancer Information System (PCIS). PCIS is applied to demonstrate how the ontology is utilized to solve the semantic heterogeneity problem from the integration of two prostate cancer related database systems at the Fox Chase Cancer Center. As the results of the integration process, the semantic query language SPARQL is applied to perform the integrated queries across the two database systems based on PCO
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