6 resultados para non-reproducibility of the cross sections

em Digital Commons at Florida International University


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This study examined relationships among variables in the Pre-International Baccalaureate (Pre-IB) Program admissions criteria and the Pre-IB Program course grades to discriminate between recipient and non recipient groups of the International Baccalaureate (IB) Diploma award. The study involved a multiracial sample of 142 IB Diploma graduates between the years 1992 and 1996 from one IB magnet school. The IB school is located within an urban high school of a predominantly Black student enrollment. A discriminant function analysis found that the highest correlations between predictors and the discriminant function were 9th- and 10th-grade mathematics and 10th-grade science course grades. Ninth-grade course grades of science, 9th-grade and 10th-grade course grades of English, foreign language, and social studies, and 7th-grade Iowa Tests of Basic Skills (ITBS) Reading Comprehension scores were also highly correlated to the discriminant function. The ITBS Battery and subscores of Vocabulary, Total Language, Total Work-Study, and Total Mathematics subscores in seventh grade and a grade point average from language arts, social studies, science, and mathematics in seventh grade were not highly correlated to the discriminant function. Recommendations were presented in the areas of curriculum and instruction, guidance services, student mentoring, and decision-making processes which would parallel the IB examination procedure and thereby enhance the alignment of the IB Program enabling more students to become recipients of the IB Diploma award. ^

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The Cross-Florida Barge Canal, synonymous with boondoggle and waste, became the cause celebre of environmental activism in Florida of the late 1960s. Dramatic changes in Florida's and the nation's politics doomed the CFBC to failure. My purpose is to place in national context the important developments and personalities of Florida's most important environmental controversy. ^ The methodology involved a series of interviews with the most important actors in the canal drama and the environmental movement. Also utilized were regional collections in Florida Public Libraries, the Florida State Archives, personal papers housed at the University of Florida and Corps of Engineers documents. Results showed a clear connection between Florida activism and national environmental policy through the influence of key individuals. I concluded that the CFBC acted as a catalyst to Florida's environmental movement, serving as an indicator of a larger political change from the New Deal coalition to the Republican realignment of 1968. ^

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Lineup procedures have recently garnered extensive empirical attention, in an effort to reduce the number of mistaken identifications that plague the criminal justice system. Relatively little attention, however, has been paid to the influence of the lineup constructor or the lineup construction technique on the quality of the lineup. This study examined whether the cross-race effect has an influence on the quality of lineups constructed using a match-to-suspect or match-to-description technique in a series of three phases. Participants generated descriptions of same- and other-race targets in Phase 1, which were used in Phase 2. In Phase 2, participants were asked to create lineups for own-race targets and other-race targets using one of two techniques. The lineups created in this phase were examined for lineup quality in Phase 3 by calculating lineup fairness assessments through the use of a mock witness paradigm. ^ Overall, the results of these experiment phases suggest that the race of those involved in the lineup construction process influences lineups. There was no difference in witness description accuracy in Phase 1, which ran counter to predictions based on the cross-race effect. The cross-race effect was observed, however, in Phases 2 and 3. The lineup construction technique used also influenced several of the process measures, selection estimates, and fairness judgments in Phase 2. Interestingly, the presence of the cross-race effect was in the opposite direction as predicted for some measures in both phases. In Phase 2, the cross-race effect was as predicted for number of foils viewed, but in the opposite direction for average time spent viewing each foil. In Phase 3, the cross-race effect was in the opposite direction than predicted, with higher levels of lineup fairness in other-race lineups. The practical implications of these findings are discussed in relation to lineup fairness within the legal system. ^

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The kaon electroproduction reaction H(e, e ′K+)Λ was studied as a function of the four momentum transfer, Q2, for different values of the virtual photon polarization parameter. Electrons and kaons were detected in coincidence in two High Resolution Spectrometers (HRS) at Jefferson Lab. Data were taken at electron beam energies ranging from 3.4006 to 5.7544 GeV. The kaons were identified using combined time of flight information and two Aerogel Čerenkov detectors used for particle identification. For different values of Q2 ranging from 1.90 to 2.35 GeV/c2 the center of mass cross sections for the Λ hyperon were determined for 20 kinematics and the longitudinal, σ L, and transverse, σT, terms were separated using the Rosenbluth separation technique. ^ Comparisons between available models and data have been studied. The comparison supports the t-channel dominance behavior for kaon electroproduction. All models seem to underpredict the transverse cross section. An estimate of the kaon form factor has been explored by determining the sensitivity of the separated cross sections to variations of the kaon EM form factor. From comparison between models and data we can conclude that interpreting the data using the Regge model is quite sensitive to a particular choice for the EM form factors. The data from the E98-108 experiment extends the range of the available kaon electroproduction cross section data to an unexplored region of Q2 where no separations have ever been performed. ^

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A high resolution study of the quasielastic 2 H(e, e'p)n reaction was performed in Hall A at the Thomas Jefferson Accelerator Facility in Newport News, Virginia. The measurements were performed at a central momentum transfer of : q: ∼ 2400 MeV/c, and at a central energy transfer of ω ∼ 1500 MeV, a four momentum transfer Q2 = 3.5 (GeV/c)2, covering missing momenta from 0 to 0.5 GeV/c. The majority of the measurements were performed at Φ = 180° and a small set of measurements were done at Φ = 0°. The Hall A High Resolution Spectrometers (HRS) were used to detect coincident electrons and protons, respectively. Absolute 2H(e, e'p) n cross sections were obtained as a function of the recoiling neutron scattering angle with respect to [special characters omitted]. The experimental results were compared to a Plane Wave Impulse Approximation (PWIA) model and to a calculation that includes Final State Interaction (FSI) effects. Experimental 2H(e, e'p)n cross sections were determined with an estimated systematic uncertainty of 7%. The general features of the measured cross sections are reproduced by Glauber based calculations that take the motion of the bound nucleons into account (GEA). Final State Interactions (FSI) contributions were found to depend strongly on the angle of the recoiling neutron with respect to the momentum transfer and on the missing momentum. We found a systematic deviation of the theoretical prediction of about 30%. At small &thetas; nq (&thetas;nq < 60°) the theory overpredicts the cross section while at large &thetas; nq (&thetas;nq > 80°) the theory underestimates the cross sections. We observed an enhancement of the cross section, due to FSI, of about 240%, as compared to PWIA, for a missing momentum of 0.4 GeV/c at an angle of 75°. For missing momentum of 0.5 GeV/c the enhancement of the cross section due to the same FSI effects, was about 270%. This is in agreement with GEA. Standard Glauber calculations predict this large contribution to occur at an angle of 90°. Our results show that GEA better describes the 2H(e, e'p)n reaction.

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Examining factors that affect vitamin D status in the fast-growing elderly population of Miami-Dade, Florida, is needed. Vitamin D deficiency in older adults has been linked to correlates of disability, including falls and fractures, and cardiovascular disease. The purpose of this study was to determine the proportion of vitamin D insufficient individuals and their relationship with vitamin D insufficiency in older adults (n=97) living in Miami-Dade. We evaluated the association between vitamin D status and 1) dual task physical performance to understand the link between vitamin D and cognition in the context of mobility; and 2) cardiometabolic risk, measured by galvanic skin response, pulse oximetry, and blood pressure to create a composite score based on autonomic nervous system and endothelial function. Participants completed baseline assessments that included serum levels of vitamin D, anthropometrics, body composition, dual task physical performance and cardiometabolic risk. Surveys to evaluate vitamin D intake, sun exposure, physical activity, and depressive symptoms were completed. Spearman’s correlations, independent t-tests, paired t-tests, repeated measures ANOVAs, and multiple logistic and linear regressions were used to examine the relationship of vitamin D insufficiency (25(OH)D /ml) and sufficiency (25(OH)D ≥30 ng/ml) with determinants of vitamin D status, dual task physical performance variables and cardiometabolic risk scores. Although the proportion of vitamin D insufficient individuals was lower when compared to the prevalance of the general United States elderly population, it was still common in healthy community-dwelling older adults living in Miami-Dade County, especially among Hispanics. Factors that affected skin synthesis (ethnicity, and sun exposure), and bioavailability/metabolism (obesity) were significant predictors of vitamin D status. Vitamin D insufficiency was not significantly correlated with worse dual task physical performance; however, cognitive performance was worse in the vitamin D insufficient group. Our results suggest a relationship of vitamin D insufficiency with executive dysfunction, and support an association with cardiometabolic risk using an innovative electro-sensor complex, possibly by modulating autonomic nervous system activity and vascular function, thus affecting cardiac performance.