916 resultados para hadron elastic and transition form factors


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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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Purpose. The purpose of the study was to examine Jamaican adolescents in a school setting, for risk factors of type 2 diabetes mellitus (T2DM) and cardiovascular diseases (CVDs). Methods. A descriptive epidemiological cross-sectional study of 276 Jamaican adolescents (112 males and 164 females) ages 14-19 years (15.6±1.2), randomly selected from grades 9-12 from ten high schools on the island. Thirteen risk factors were examined. Risk factors were compared with BMI levels and demographics. A sub-study validated finger prick testing of fasting blood glucose, total cholesterol, and HbA1c versus venous testing in 59 subjects. Results. Prevalence of overweight was 33.0% (n=91) with mean BMI of 23.74±7.74. Approximately 66.7% of subjects reported ≥ 3 risk factors. The number of T2DM and CVDs risk factors increased for subjects with BMI above 25. One third of the overweight subjects were classified with the metabolic syndrome. High BMI was associated with high waist circumference (r = .767, p < .01), high waist-to-hip ratio (r = .180, p < .01), presence of Acanthosis Nigricans (r = .657, p < .01), high total cholesterol (r = .158, p < .01), family history of T2DM (r = .157, p < .01), and hypertension (r = .422, p < .01). Regression analyses significantly predicted gender and physical activity (p < .001), and total number of risk factors for T2DM and CVDs (p < .001). Paired samples t-tests revealed no significant differences between methods of testing for TC and HbA1c (p < .01) but not for FBG (p > .05). Percentage bias for the methods of blood testing met the reference standards for fasting blood glucose but not for total cholesterol and HbA1c. Bland Altman tests of agreement between the two methods indicated good agreement for all three tests. Conclusion. Jamaican adolescents are at high risk for T2DM and CVDs as seen in other study populations. Effective programs to prevent T2DM and CVDs are needed. Family history of diseases, anthropometric measures, and gender identified more subjects at risk than did the biochemical measures. Comparison between finger prick and venous blood methods suggested that finger prick is an adequate method to screen for risk factors in children and adolescents.

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This study examined the relationships among dietary intake, substance use, socioeconomic and acculturation-related factors among Latinas in Miami-Dade County. Substance abuse is rising among Latinas. A fuller understanding of this problem is needed given the rise of the Hispanic population and the role of women in Latin society. A better understanding between substance use and dietary intake can guide nutrition interventions to reduce negative substance-related health consequences. A purposeful sample of 320 Latina mother/daughter dyads were recruited and interviewed face-to-face as part of the Latino Women's Study. Dietary intake was collected via a 24-hour recall and examined by (1) nutrient intake, (2) dietary patterns using cluster analysis, (3) quality of diet using the Healthy Eating Index (HEI) and (4) the Dietary Reference Intakes to determine nutrient adequacy. Substance use was measured with the Drug Use Frequency and the Healthy and Daily Living Form. Acculturation was measured with the Cultural Identity Scale. Three dietary patterns emerged based on the number of servings from the food groups established in MyPyramid. None were associated with substance use. Latinas who reported using cannabis, cocaine, sedatives without prescription and/or more than five alcoholic drinks on an occasion at least once a month during the previous twelve months had significantly lower HEI scores (64 vs. 60; F = 7.8, p = .005) and consumed fewer fruits (F = 16, p < .001) than non-users. Latinas classified as mothers whom reported consuming cannabis at least 1-7 times a week had significantly lower HEI scores (F = 4.23, p = .015, η2 = .027) than daughters with the same frequency of substance use. One dimension of acculturation, greater familiarity with Latin culture, was associated with good dietary quality (β = .142, p = .012) regardless of any type of substance used or income level. There was a high prevalence of inadequacy of folic acid intake (50-75%) regardless of substance use. Substance users consumed significantly more energy (1,798 vs. 1,615; p = .027) than non-users. Although effect sizes were small, associations between dietary intake and substance use among Latinas deserve further exploration while acknowledging the combined association with acculturation. ^

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Hepatitis C infection (HCV) continues to disproportionately affect Hispanics/Latinos in the United States. Hispanic/Latino intravenous drug users (IDUs), because of their risky injection and sexual behaviors, are prone to HCV infection and rapid transmission of the virus to others via several routes. With a prevalence rate of approximately 75% among IDUs, it is imperative that transmission of HCV be prevented in this population. This study aims to examine the associations between demographic, injection and sexual risk factors to HCV infection in a group Hispanic/Latino IDUs in Miami-Dade County, Florida. Preliminary unadjusted results in this sample reveal that age (OR=4.592, p=0.004), weekly injection (OR=5.171, p=0.000), daily injection frequency (OR=3.856, p=0.000) and use of a dirty needle (OR=2.320, p= 0.006) were all significantly associated with HCV infection. Being born outside the U.S. was significantly negatively associated with HCV infection (OR=0.349, p=0.004). Additionally, having two or more sex partners in the past three months (OR=0.472, p=0.014) was negatively associated with HCV infection. After adjusting for all other variables, older age (AOR=7.470, p=0.006), weekly injection (AOR=3.238, p=0.007) and daily injection frequency (AOR=2.625, p=0.010) were all significantly associated with HCV infection. Being born outside the U.S. (AOR=0.369, p=0.019) was a significant protective factor for HCV infection, along with having two or more sex partners in the past three months (AOR=0.481, p=0.037). When analyzing the significant variables in a backward regression model, having 2 or more sex partners in the past three months was not significant at the p

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County jurisdictions in America are increasingly exercising self-government in the provision of public community services through the context of second order federalism. In states exercising this form of contemporary governance, county governments with "reformed" policy-making structures and professional management practices, have begun to rival or surpass municipalities in the delivery of local services with regional implications such as environmental protection (Benton 2002, 2003; Marando and Reeves, 1993). ^ The voter referendum, a form of direct democracy, is an important component of county land preservation and environmental protection governmental policies. The recent growth and success of land preservation voter referendums nationwide reflects an increase in citizen participation in government and their desire to protect vacant land and its natural environment from threats of over-development, urbanization and sprawl, loss of open space and farmland, deterioration of ecosystems, and inadequate park and recreational amenities. ^ The study's design employs a sequential, mixed method. First, a quantitative approach employs the Heckman two-step model. It is fitted with variables for the non-random sample of 227 voter referendum counties and all non-voter referendum counties in the U.S. from 1988 to 2009. Second, the qualitative data collected from the in-depth investigation of three South Florida county case studies with twelve public administrator interviews is transformed for integration with the quantitative findings. The purpose of the qualitative method is to complement, explain and enrich the statistical analysis of county demographic, socio-economic, terrain, regional, governance and government, political preference, environmentalism, and referendum-specific factors. ^ The research finds that government factors are significant in terms of the success of land preservation voter referendums; more specifically, the presence of self-government authority (home rule charter), a reformed structure (county administrator/manager or elected executive), and environmental interest groups. In addition, this study concludes that successful counties are often located coastal, exhibit population and housing growth, and have older and more educated citizens who vote democratic in presidential elections. The analysis of case study documents and public administrator interviews finds that pragmatic considerations of timing, local politics and networking of regional stakeholders are also important features of success. Further research is suggested utilizing additional public participation, local government and public administration factors.^

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This study examined relationships among self-esteem, remedial academic placement, ethnicity, gender, and enrollment status, using a nonexperimental, ex post facto research design. Participants were 113 freshman community college students attending Broward Community College in South Florida. The Coopersmith Self-Esteem Inventory (Adult Form) was used to measure the self-esteem of the participants. The results of this study indicate a significant difference between the mean self-esteem levels of the students enrolled in remedial academic classes (m = 66.08) and those enrolled in regular academic classes (m = 73.97). An independent samples t-test at the.05 significance level indicated that regular students were found to have higher levels of self-esteem than remedial students (t(112) = 2.14, p =.03). Two-way analyses of variance of placement status by ethnicity, of placement status by gender, and of placement status by enrollment status on self-esteem were also conducted. Interactions between placement status and the other factors were not found to be significant (p $>$.05). However, a significant main effect for ethnicity was found (p $<$.05). The results indicated that white students had a mean self-esteem level (m = 75.30) significantly higher than non-white students (m = 62.76, p =.002).^ The results of this study suggests that many community college students have problems related to self-esteem. Further research should be conducted on remedial and minority college students using a larger sample size and additional variables, such as socio-economic status. ^

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The purpose of this study is two-fold: (1) to investigate the common factors positively influencing academically successful, highly motivated African-American high school students in their educational pursuits; and (2) to determine ways in which educators can facilitate an increased positive impact on minority students' achievement motivation and transition to higher education. ^ Three sources of data inform the qualitative study. Short autobiographical essays address the topic of antecedent factors influencing the students' selection of an academic program of study. Individual interviews using a semi-structured format elicit discussion of prior experiences and influences related to the research sub-questions. Focus group interviews elicit discussion of emergent patterns perceived by the researcher from the autobiographical essays and individual interviews. ^ Results indicate a generic model for success for high achieving African-American students. Students prioritize education as a means to success in life. They receive strong support for educational aspirations from at least one adult within the home. The students are focused on a professional career in the future. The students realize and desire the financial benefits of academic success. The students desire academic challenge. Students have feelings of control over their academic choices; however, they frequently seek the counsel of family members. Prior experience in honors, gifted, or magnet programs did not meet needs. ^ Recommendations for improved educational experiences include: Increase teacher and counselor responsiveness to students. Provide classroom activities which afford more interaction among the students and teacher and relate curriculum to topics of interest. Increase involvement of parents and Black community members in establishing goals and visions of opportunity. Recognize and revere diversity among students within the classroom environment. Set a climate that assumes more individual student responsibility and sets higher academic expectations. ^ The factors influencing academically successful, highly motivated African-American high school students echo the patterns of experiences of many groups. Pride in achievement, emotional support for efforts, expectations of success, independence in thought, and consternation with mediocrity and malaise drive the students to excel academically just like all others who succeed. ^

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The study of obesity has evolved into one of the most important public health issues in the United States (U.S.), particularly in Hispanic populations. Mexican Americans, the largest Hispanic ethnic subgroup in the U.S., have been significantly impacted by obesity and related cardiovascular diseases. Mexican Americans living in the Lower Rio Grande Valley (the Valley) in the Texas-Mexico border are one of the most disadvantaged and hard-to-reach minority groups. Demographic factors, socioeconomic status, acculturation, and physical activity behavior have been found to be important predictors of health, although research findings are mixed when establishing predictors of obesity in this population. Furthermore, while obesity has long been linked to cardiovascular disease (CVD) risk factors such as hypertension, type 2 diabetes, and dyslipidemia; information on the relationships between obesity and these CVD risk factors have been mostly from non-minority population groups. Overall, research has been mixed in establishing the association between obesity and related CVD risk factors in this population calling attention to the need for further research. Nevertheless, identifying predictors of success for weight loss in this population will be important if health disparities are to be addressed. The overall objective of the findings presented in this dissertation was to attain a more informed profile of obesity and CVD risk factors in this population. In particular, we examined predictors of obesity, measures of obesity and association with cardiovascular disease risk factors in a sample of 975 Mexican Americans participating in a health promotion program in the Valley region. Findings suggest acculturation factors to be one of the most important predictors of obesity in this population. Results also point to the need of identifying other possible risk factors for predicting CVD risk. Finally, initial body mass index is an important predictor of weight loss in this population group. Thus, indicating that this population is not only amenable to change, but that improvements in weight loss are feasible. This finding strengthens the relevance of prevention programs such as Beyond Sabor for Mexican populations at risk, in particular, food bank recipients.

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Purpose: The purpose of the study was to examine Jamaican adolescents in a school setting, for risk factors of type 2 diabetes mellitus (T2DM) and cardiovascular diseases (CVDs). Methods: A descriptive epidemiological cross-sectional study of 276 Jamaican adolescents (112 males and 164 females) ages 14-19 years (15.6±1.2), randomly selected from grades 9-12 from ten high schools on the island. Thirteen risk factors were examined. Risk factors were compared with BMI levels and demographics. A sub-study validated finger prick testing of fasting blood glucose, total cholesterol, and HbAlc versus venous testing in 59 subjects. Results: Prevalence of overweight was 33.0% (n=91) with mean BMI of 23.74±7.74. Approximately 66.7% of subjects reported > 3 risk factors. The number of T2DM and CVDs risk factors increased for subjects with BMI above 25. One third of the overweight subjects were classified with the metabolic syndrome. High BMI was associated with high waist circumference (r =.767, p (r = .180, p.05). Percentage bias for the methods of blood testing met the reference standards for fasting blood glucose but not for total cholesterol and HbAlc. Bland Altman tests of agreement between the two methods indicated good agreement for all three tests. Conclusion: Jamaican adolescents are at high risk for T2DM and CVDs as seen in other study populations. Effective programs to prevent T2DM and CVDs are needed. Family history of diseases, anthropometric measures, and gender identified more subjects at risk than did the biochemical measures. Comparison between finger prick and venous blood methods suggested that finger prick is an adequate method to screen for risk factors in children and adolescents.

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If you are the rightful copyright holder of this dissertation or thesis and wish to have it removed from the Open Access Collection, please submit a request to dcc@fiu.edu and include clear identification of the work, preferably with URL.

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It is widely believed that wading birds in the Everglades have declined as a result of historic water management practices. I determined growth rates for Snowy Egret (Egretta thula) chicks by assessed the nestling body condition through measurement of body weight and skeletal traits. A growth index was calculated as a residual of body weight regressed on age. A body condition index was calculated as the residual of body weight regressed on a skeletal trait (tarsus). Growth was significantly related to water level and hatch date. Survival rates were calculated to day 14, 21, and 50. Survival to 50 days of age was significantly related to hatch date and order. Survival to 21 days of age was significantly related to water level and hatching order. Survival to 14 days of age was marginally related to hatching order. Growth and survival is greatly influenced by water level and hatch date.

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Background Self-harm places an individual at increased risk of future self-harm and suicide, and indicates distress and maladaptive coping. Those who present to hospital with self-cutting form a significant minority of self-harm patients who are at increased risk of prospective repetition of self-harm and suicide compared with those presenting with intentional overdose. In addition to increased risk, there is emerging evidence of demographic, psychological, clinical, and social differences between those presenting with self-cutting and those presenting with overdose. Aim and Key Objectives The aim of the current doctoral work was to examine in detail the association between presenting with self-cutting and risk of prospective repetition. The objectives were: to identify evidence-based risk factors for repetition of self-harm among those presenting to emergency departments with self-harm; to compare demographic and presentation characteristics and prospective repetition across presentations of self-cutting only, self-cutting plus intentional overdose, and intentional overdose only; to compare prospective repetition and other characteristics within self-cutting presentations based on the type of treatment received; to compare self-cutting and intentional overdose patients on psychological risk and protective factors for repetition; and to examine the lived experience of engaging in repeated overdose and self-cutting. Methods The current doctoral work used a mixed-methods approach and is comprised of one systematic review and four empirical studies. The empirical studies were two registry-based prospective studies of Irish hospital presentations of self-harm, one prospective structured interview study, and one qualitative study using Interpretative Phenomenological Analysis. Results The systematic review identified several consistent and emerging risk factors for repetition of self-harm, compared to which self-cutting had a medium-sized effect. The registry studies demonstrated that the involvement of self-cutting, particularly less medically severe selfcutting, confers an increased risk of 1-month and 12-month repetition among Irish index selfharm presentations. The structured psychological study detected higher hopelessness and lower non-reactivity to inner experience among those presenting with self-cutting, and higher depression among those who repeated self-harm. Repeaters had lower baseline levels of protective psychological factors than non-repeaters and continued to have higher depression and hopelessness at follow-up. Finally, the qualitative study indicated that self-harm is a purposeful action taken in response to an overwhelming situation and is evaluated afterwards in terms of personal and social effects. Chosen method of self-harm seemed to be influenced by the desired outcome of the self-harm act, capability, accessibility and previous experience. Conclusion Despite limitations in terms of recruitment rates, the work presented in this thesis is innovative in examining the issue of the association between self-cutting and repetition from multiple perspectives. No one factor can reliably predict all repetition but self-cutting represents one consistent and easily detected risk factor for repetition. Those who present with self-cutting exhibit significant differences on demographic, clinical, and psychological variables compared with those presenting with intentional overdose, and seem to exhibit a more vulnerable profile. However, those who present with self-cutting do not form a discrete or homogenous group, and self-harm methods and levels of suicidal intent are liable to fluctuate over time.

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This thesis describes a systematic investigation of the mechanistic and synthetic aspects of intramolecular reactions of a series of α-diazo-β-oxo sulfone derivatives using copper and, to a lesser extent, rhodium catalysts. The key reaction pathways explored were C–H insertion and cyclopropanation, with hydride transfer competing in certain instances. Significantly, up to 98% ee has been achieved in the C–H insertion processes using copper-NaBARF-bisoxazoline catalysts, with the presence of the additive NaBARF critical to the efficiency of the transformations. This novel synthetic methodology provides access to a diverse range of enantioenriched heterocyclic compounds including thiopyrans, sulfolanes, β- and γ-lactams, in addition to carbocycles such as fused cyclopropanes. The synthesis of the α-diazosulfones required for subsequent investigations is initially described. Of the twenty seven diazo sulfones described, nineteen are novel and are fully characterised in this work. The discussion is subsequently focused on a study of the copper and rhodium catalysed reactions of the α-diazosulfones with Chapter Four concentrated on highly enantioselective C–H insertion to form thiopyrans and sufolanes, Chapter Five focused on C–H insertion to form fused sulfolanes, Chapter Six focused on C–H insertion in sulfonyl α-diazoamides where both lactam formation and / or thiopyran / sulfolane formation can result from competing C–H insertion pathways, while Chapter Seven focuses on cyclopropanation to yield fused cyclopropane derviatives. One of the key outcomes of this work is an insight into the steric and / or electronic factors on both the substrate and the catalyst which control regio-, diastereo- and enantioselectivity patterns in these synthetically powerful transformations. Full experimental details for the synthesis and spectral characterisation of the compounds are included at the end of each Chapter, with details of chiral stationary phase HPLC analysis and assignment of absolute stereochemistry included in the appendix.

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Numerous works have been conducted on modelling basic compliant elements such as wire beams, and closed-form analytical models of most basic compliant elements have been well developed. However, the modelling of complex compliant mechanisms is still a challenging work. This paper proposes a constraint-force-based (CFB) modelling approach to model compliant mechanisms with a particular emphasis on modelling complex compliant mechanisms. The proposed CFB modelling approach can be regarded as an improved free-body- diagram (FBD) based modelling approach, and can be extended to a development of the screw-theory-based design approach. A compliant mechanism can be decomposed into rigid stages and compliant modules. A compliant module can offer elastic forces due to its deformation. Such elastic forces are regarded as variable constraint forces in the CFB modelling approach. Additionally, the CFB modelling approach defines external forces applied on a compliant mechanism as constant constraint forces. If a compliant mechanism is at static equilibrium, all the rigid stages are also at static equilibrium under the influence of the variable and constant constraint forces. Therefore, the constraint force equilibrium equations for all the rigid stages can be obtained, and the analytical model of the compliant mechanism can be derived based on the constraint force equilibrium equations. The CFB modelling approach can model a compliant mechanism linearly and nonlinearly, can obtain displacements of any points of the rigid stages, and allows external forces to be exerted on any positions of the rigid stages. Compared with the FBD based modelling approach, the CFB modelling approach does not need to identify the possible deformed configuration of a complex compliant mechanism to obtain the geometric compatibility conditions and the force equilibrium equations. Additionally, the mathematical expressions in the CFB approach have an easily understood physical meaning. Using the CFB modelling approach, the variable constraint forces of three compliant modules, a wire beam, a four-beam compliant module and an eight-beam compliant module, have been derived in this paper. Based on these variable constraint forces, the linear and non-linear models of a decoupled XYZ compliant parallel mechanism are derived, and verified by FEA simulations and experimental tests.

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The study of obesity has evolved into one of the most important public health issues in the United States (U.S.), particularly in Hispanic populations. Mexican Americans, the largest Hispanic ethnic subgroup in the U.S., have been significantly impacted by obesity and related cardiovascular diseases. Mexican Americans living in the Lower Rio Grande Valley (the Valley) in the Texas-Mexico border are one of the most disadvantaged and hard-to-reach minority groups. Demographic factors, socioeconomic status, acculturation, and physical activity behavior have been found to be important predictors of health, although research findings are mixed when establishing predictors of obesity in this population. Furthermore, while obesity has long been linked to cardiovascular disease (CVD) risk factors such as hypertension, type 2 diabetes, and dyslipidemia; information on the relationships between obesity and these CVD risk factors have been mostly from non-minority population groups. Overall, research has been mixed in establishing the association between obesity and related CVD risk factors in this population calling attention to the need for further research. Nevertheless, identifying predictors of success for weight loss in this population will be important if health disparities are to be addressed. The overall objective of the findings presented in this dissertation was to attain a more informed profile of obesity and CVD risk factors in this population. In particular, we examined predictors of obesity, measures of obesity and association with cardiovascular disease risk factors in a sample of 975 Mexican Americans participating in a health promotion program in the Valley region. Findings suggest acculturation factors to be one of the most important predictors of obesity in this population. Results also point to the need of identifying other possible risk factors for predicting CVD risk. Finally, initial body mass index is an important predictor of weight loss in this population group. Thus, indicating that this population is not only amenable to change, but that improvements in weight loss are feasible. This finding strengthens the relevance of prevention programs such as Beyond Sabor for Mexican populations at risk, in particular, food bank recipients.