898 resultados para predictor variable
Resumo:
The present study was designed to elucidate sex-related differences in two basic auditory and one basic visual aspect of sensory functioning, namely sensory discrimination of pitch, loudness, and brightness. Although these three aspects of sensory functioning are of vital importance in everyday life, little is known about whether men and women differ from each other in these sensory functions. Participants were 100 male and 100 female volunteers ranging in age from 18 to 30 years. Since sensory sensitivity may be positively related to individual levels of intelligence and musical experience, measures of psychometric intelligence and musical background were also obtained. Reliably better performance for men compared to women was found for pitch and loudness, but not for brightness discrimination. Furthermore, performance on loudness discrimination was positively related to psychometric intelligence, while pitch discrimination was positively related to both psychometric intelligence and levels of musical training. Additional regression analyses revealed that each of three predictor variables (sex, psychometric intelligence, and musical training) accounted for a statistically significant portion of unique variance in pitch discrimination. With regard to loudness discrimination, regression analysis yielded a statistically significant portion of unique variance for sex as a predictor variable, whereas psychometric intelligence just failed to reach statistical significance. The potential influence of sex hormones on sex-related differences in sensory functions is discussed.
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It is widely acknowledged in theoretical and empirical literature that social relationships, comprising of structural measures (social networks) and functional measures (perceived social support) have an undeniable effect on health outcomes. However, the actual mechanism of this effect has yet to be clearly understood or explicated. In addition, comorbidity is found to adversely affect social relationships and health related quality of life (a valued outcome measure in cancer patients and survivors). ^ This cross sectional study uses selected baseline data (N=3088) from the Women's Healthy Eating and Living (WHEL) study. Lisrel 8.72 was used for the latent variable structural equation modeling. Due to the ordinal nature of the data, Weighted Least Squares (WLS) method of estimation using Asymptotic Distribution Free covariance matrices was chosen for this analysis. The primary exogenous predictor variables are Social Networks and Comorbidity; Perceived Social Support is the endogenous predictor variable. Three dimensions of HRQoL, physical, mental and satisfaction with current quality of life were the outcome variables. ^ This study hypothesizes and tests the mechanism and pathways between comorbidity, social relationships and HRQoL using latent variable structural equation modeling. After testing the measurement models of social networks and perceived social support, a structural model hypothesizing associations between the latent exogenous and endogenous variables was tested. The results of the study after listwise deletion (N=2131) mostly confirmed the hypothesized relationships (TLI, CFI >0.95, RMSEA = 0.05, p=0.15). Comorbidity was adversely associated with all three HRQoL outcomes. Strong ties were negatively associated with perceived social support; social network had a strong positive association with perceived social support, which served as a mediator between social networks and HRQoL. Mental health quality of life was the most adversely affected by the predictor variables. ^ This study is a preliminary look at the integration of structural and functional measures of social relationships, comorbidity and three HRQoL indicators using LVSEM. Developing stronger social networks and forming supportive relationships is beneficial for health outcomes such as HRQoL of cancer survivors. Thus, the medical community treating cancer survivors as well as the survivor's social networks need to be informed and cognizant of these possible relationships. ^
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Cancer of the oral cavity and pharynx remains one of the ten leading causes of cancer death in the United States (US). Besides smoking and alcohol consumption, there are no well established risk factors. While poor dental care had been implicated, it is unknown if the lack of dental care, implying poor dental hygiene predisposes to oral cavity cancer. This study aimed to assess the relationship between dental care utilization during the past twelve months and the prevalence of oral cavity cancer. A cross-sectional design of the National Health Interview Survey of adult, non-institutionalized US residents (n=30,475) was used to assess the association between dental care utilization and self reported diagnosis of oral cavity cancer. Chi square statistic was used to examine the crude association between the predictor variable, dental care utilization and other covariates, while unconditional logistic regression was used to assess the relationship between oral cavity cancer and dental care utilization. There were statistically significant differences between those who utilized dental care during the past twelve months and those who did not with respect to education, income, age, marital status, and gender (p < 0.05), but not health insurance coverage (p = 0.53). Also, those who utilized dental care relative to those who did not were 65% less likely to present with oral cavity cancer, prevalence odds ratio (POR), 0.35, 95% Confidence Interval (CI), 0.12–0.98. Further, higher income advanced age, people of African heritage, and unmarried status were statistically significantly associated with oral cavity cancer, (p < 0.05), but health insurance coverage, alcohol use and smoking were not, p > 0.05. However, after simultaneously controlling for the relevant covariates, the association between dental care and oral cavity cancer did not attenuate nor persist. Thus, compared with those who did not use dental care, those who did wee 62% less likely to present with oral cavity cancer adjusted POR, 0.38, 95% CI, 0.13-1.10. Among US adults residing in community settings, use of dental care during the past twelve months did not significantly reduce the predisposition to oral cavity cancer. However, due to the nature of the data used in this study, which restricts temporal sequence, a large sample prospective study that may identify modifiable factors associated with oral cancer development namely poor dental care, is needed. ^
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Asthma is a chronic complex disorder of the respiratory tract that affects millions of people globally, a large percentage of which are children. Triggered by a host of factors such as allergens and changes in temperature, the pathophysiologic and clinical indices vary among patients and have contributed to difficulties in overall management of asthma. Shortly after exhaled nitric oxide (eNO) was discovered in higher concentrations in asthma patients, it was shown to be superior to other markers such as PEFR, FEV1 and sputum eosinophils in screening asthma patients. Studies have also noted promising results regarding the use of eNO to predict asthma exacerbation in adults while in children, asthma symptoms have been observed to be good predictors of asthma exacerbation. Currently however, the potential of eNO as a predictor of asthma exacerbation in children is yet to be examined. The objective of this study was to assess eNO potential to predict asthma exacerbation in children by examining the relationship between eNO and changes in pulmonary function, asthma symptoms and rescue medication use.^ The primary study "Air Toxics and Asthma in Children" (ATAC), recruited children aged 9 to 14 years with labile persistent asthma diagnosed at least one year earlier. The data obtained from 30 study participants, included exhaled nitric oxide concentration, PEFR, FEV1, asthma symptoms and frequency of emergency medication use.^ Descriptive statistics, Pearson's and Spearman's correlation tests were followed by a simple linear regression in which eNO was the independent (predictor) variable while FEV1, PEFR, asthma symptoms and frequency of emergency medication use were the dependent (outcome) variables.^ Results showed that eNO was associated with percent change in FEV1, day time wheeze, night time shortness of breath, but correlated only weakly with PEFR, amplitude percent of mean PEFR, FEV1, percent change in FEV1 and asthma symptoms.^ Further research is imperative to better define the role of eNO and understand intrinsic pathologic mechanisms towards asthma management in children.^
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Back ground and Purpose. There is a growing consensus among health care researchers that Quality of Life (QoL) is an important outcome and, within the field of family caregiving, cost effectiveness research is needed to determine which programs have the greatest benefit for family members. This study uses a multidimensional approach to measure the cost effectiveness of a multicomponent intervention designed to improve the quality of life of spousal caregivers of stroke survivors. Methods. The CAReS study (Committed to Assisting with Recovery after Stroke) was a 5-year prospective, longitudinal intervention study for 159 stroke survivors and their spousal caregivers upon discharge of the stroke survivor from inpatient rehabilitation to their home. CAReS cost data were analyzed to determine the incremental cost of the intervention per caregiver. The mean values of the quality-of-life predictor variables of the intervention group of caregivers were compared to the mean values of usual care groups found in the literature. Significant differences were then divided into the cost of the intervention per caregiver to calculate the incremental cost effectiveness ratio for each predictor variable. Results. The cost of the intervention per caregiver was approximately $2,500. Statistically significant differences were found between the mean scores for the Perceived Stress and Satisfaction with Life scales. Statistically significant differences were not found between the mean scores for the Self Reported Health Status, Mutuality, and Preparedness scales. Conclusions. This study provides a prototype cost effectiveness analysis on which researchers can build. Using a multidimensional approach to measure QoL, as used in this analysis, incorporates both the subjective and objective components of QoL. Some of the QoL predictor variable scores were significantly different between the intervention and comparison groups, indicating a significant impact of the intervention. The estimated cost of the impact was also examined. In future studies, a scale that takes into account both the dimensions and the weighting each person places on the dimensions of QoL should be used to provide a single QoL score per participant. With participant level cost and outcome data, uncertainty around each cost-effectiveness ratio can be calculated using the bias-corrected percentile bootstrapping method and plotted to calculate the cost-effectiveness acceptability curves.^
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The climatic conditions of mountain habitats are greatly influenced by topography. Large differences in microclimate occur with small changes in elevation, and this complex interaction is an important determinant of mountain plant distributions. In spite of this, elevation is not often considered as a relevant predictor in species distribution models (SDMs) for mountain plants. Here, we evaluated the importance of including elevation as a predictor in SDMs for mountain plant species. We generated two sets of SDMs for each of 73 plant species that occur in the Pacific Northwest of North America; one set of models included elevation as a predictor variable and the other set did not. AUC scores indicated that omitting elevation as a predictor resulted in a negligible reduction of model performance. However, further analysis revealed that the omission of elevation resulted in large over-predictions of species' niche breadths-this effect was most pronounced for species that occupy the highest elevations. In addition, the inclusion of elevation as a predictor constrained the effects of other predictors that superficially affected the outcome of the models generated without elevation. Our results demonstrate that the inclusion of elevation as a predictor variable improves the quality of SDMs for high-elevation plant species. Because of the negligible AUC score penalty for over-predicting niche breadth, our results support the notion that AUC scores alone should not be used as a measure of model quality. More generally, our results illustrate the importance of selecting biologically relevant predictor variables when constructing SDMs.
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Pregnancy leads to several changes in body composition and morphology of women. It is not clear whether the biomechanical changes occurring in this period are due exclusively to body composition and size or to other physiological factors. The purpose was to quantify the morphology and body composition of women throughout pregnancy and in the postpartum period and identify the contribution of these parameters on the lower limb joints kinetic during gait. Eleven women were assessed longitudinally, regarding anthropometric, body composition, and kinetic parameters of gait. Body composition and body dimensions showed a significant increase during pregnancy and a decrease in the postpartum period. In the postpartum period, body composition was similar to the 1st trimester, except for triceps skinfold, total calf area, and body mass index, with higher results than at the beginning of pregnancy. Regression models were developed to predict women’s internal loading through anthropometric variables. Four models include variables associated with the amount of fat; four models include variables related to overall body weight; three models include fat-free mass; one model includes the shape of the trunk as a predictor variable. Changes in maternal body composition and morphology largely determine kinetic dynamics of the joints in pregnant women.
Resumo:
Pregnancy leads to several changes in body composition and morphology of women. It is not clear whether the biomechanical changes occurring in this period are due exclusively to body composition and size or to other physiological factors. The purpose was to quantify the morphology and body composition of women throughout pregnancy and in the postpartum period and identify the contribution of these parameters on the lower limb joints kinetic during gait. Eleven women were assessed longitudinally, regarding anthropometric, body composition, and kinetic parameters of gait. Body composition and body dimensions showed a significant increase during pregnancy and a decrease in the postpartum period. In the postpartum period, body composition was similar to the 1st trimester, except for triceps skinfold, total calf area, and body mass index, with higher results than at the beginning of pregnancy. Regression models were developed to predict women’s internal loading through anthropometric variables. Four models include variables associated with the amount of fat; four models include variables related to overall body weight; three models include fat-free mass; one model includes the shape of the trunk as a predictor variable. Changes in maternal body composition and morphology largely determine kinetic dynamics of the joints in pregnant women.
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Long-term forecasts of pest pressure are central to the effective management of many agricultural insect pests. In the eastern cropping regions of Australia, serious infestations of Helicoverpa punctigera (Wallengren) and H. armigera (Hübner)(Lepidoptera: Noctuidae) are experienced annually. Regression analyses of a long series of light-trap catches of adult moths were used to describe the seasonal dynamics of both species. The size of the spring generation in eastern cropping zones could be related to rainfall in putative source areas in inland Australia. Subsequent generations could be related to the abundance of various crops in agricultural areas, rainfall and the magnitude of the spring population peak. As rainfall figured prominently as a predictor variable, and can itself be predicted using the Southern Oscillation Index (SOI), trap catches were also related to this variable. The geographic distribution of each species was modelled in relation to climate and CLIMEX was used to predict temporal variation in abundance at given putative source sites in inland Australia using historical meteorological data. These predictions were then correlated with subsequent pest abundance data in a major cropping region. The regression-based and bioclimatic-based approaches to predicting pest abundance are compared and their utility in predicting and interpreting pest dynamics are discussed.
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The present study contributes to theory and practice through the development of a model of shift-work tolerance with the potential to indicate interventions that reduce nurses' intention toward turnover and increase job satisfaction in hospital-based settings. Survey data from 1257 nurses were used to conduct structural equation modeling that examine the direct and indirect effects of supervisor and colleague support, team identity, team climate, and control over working environment on time-based work/life conflict, psychological well-being, physical symptoms, job satisfaction, and turnover intention. The analysis of the proposed model revealed a good fit The chi-square difference test was non-significant (χ2(26)=338.56), the fit indices were high (CFI=.923, NFI=.918, and NNFI=.868), the distribution of residuals was symmetric and approached zero, the average standardized residual was low (AASR=.04), and the standardized RMR was .072. In terms of the predictor variable, the final model explained 48% of the variance in turnover intention. The data revealed considerable evidence of both direct effects on adjustment and complex indirect links between levels of adjustment and work-related social support, team identity, team climate, and control. Nurses with high supervisor and coworker support experienced more positive team climates, identified more strongly with their team, and increased their perceptions of control over their work environment. This in turn lowered their appraisals of their time-based work/life conflict, which consequently increased their psychological well-being and job satisfaction and reduced their physical health symptoms and turnover intention. The type of shift schedule worked by the nurses influenced levels of turnover intention, control over work environment, time-based work/life conflict, and physical symptoms.
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This dissertation identifies, examines, and assesses the relative influence of identified empirically and conceptually relevant variables on incarcerated substance abusers' expectations of postrelease adjustment. A purposive sampling procedure was used to recruit 101 male and female substance-abusing offenders participating in prison- and jail-based drug treatment programs in south Florida. A 92-item survey questionnaire was used to collect basic demographic data; measure inmate preincarceration characteristics, social support, and rehabilitation program participation; and record archival data. Regression equations were developed utilizing ten different measures of the participants' expectations of their postrelease adjustment. Two equations yielded statistically significant F ratios; maintaining a stable living and maintaining abstinence. Twenty-two percent of the variance in respondents' expectations of maintaining a stable living was explained by preincarceration characteristics, social support, and rehabilitation program participation (F = 1.89; df = 13,87; p $<$.05). The only significant predictor variable was perception of social support (b = $-$.05; t = $-$3.6; p $<$.001). Twenty-three percent of the variance in respondents' expectations of maintaining abstinence from substances was explained by preincarceration characteristics, social support, and rehabilitation program participation (F = 2; df = 13,87; p $<$.05). Once again, the only significant predictor variable was perception of social support. The results of the analyses indicate that social support was the only important variable for understanding these respondents' efficacy expectations of postrelease abstinence and stable living. The results of this investigation demonstrate the complexity of the social support variable for prisoners, and identify social support as a potential rehabilitative resource for substance-abusing inmates. The results of this investigation underscore the importance of continued, detailed empirical study in order to understand and clarify how social support, efficacy expectations, and actual postrelease performance interrelate for this population of offenders.
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Math anxiety levels and performance outcomes were compared for bilingual and monolingual community college Intermediate Algebra students attending a culturally diverse urban commuter college. Participants (N = 618, 250 men, 368 women; 361 monolingual, 257 bilingual) completed the Abbreviated Math Anxiety Scale (AMAS) and a demographics instrument. Bilingual and monolingual students reported comparable mean AMAS scores (20.6 and 20.7, respectively) and comparable proportions of math anxious individuals (50% and 48%, respectively). Factor analysis of AMAS scores, using principal component analysis by varimax rotation, yielded similar two-factor structures for both populations -- assessment and learning content -- accounting for 65.6% of the trace for bilingual AMAS scores. Statistically significant predictor variables for levels of math anxiety for the bilingual participants included (a) preparatory course enrollment (β = .236, p = .041) with those enrolled in prior preparatory courses scoring higher, (b) education major (β = .285, p = .018) with education majors scoring higher, and (c) business major (β = .252, p = .032) with business majors scoring higher. One statistically significant predictor variable emerged for monolingual students, gender (β = -.085, p = .001) with females ranking higher. Age, income, race, ethnicity, U.S. origin, science or health science majors did not emerge as statistically significant predictor variables for either group.^ Similarities between monolingual and bilingual participants included statistically significant negative linear correlations between AMAS scores and course grades for both bilingual (r = -.178, p = .017) and monolingual participants (r = -.203, p = .001). Differences included a statistically significant linear correlation between AMAS scores and final exam grades for monolingual participants only (r = -.253, p < .0009) despite no statistically significant difference in the strength the linear relationship of the AMAS scores and the final exam scores between groups, z = 1.35, p = .1756.^ The findings show that bilingual and monolingual students report math anxiety similarly and that math anxiety has similar associations with performance measures, despite differences between predictor variables. One of the first studies on the math anxiety of bilingual community college students, the results suggest recommendations for researchers and practitioners.^
Resumo:
Math anxiety levels and performance outcomes were compared for bilingual and monolingual community college Intermediate Algebra students attending a culturally diverse urban commuter college. Participants (N = 618, 250 men, 368 women; 361 monolingual, 257 bilingual) completed the Abbreviated Math Anxiety Scale (AMAS) and a demographics instrument. Bilingual and monolingual students reported comparable mean AMAS scores (20.6 and 20.7, respectively) and comparable proportions of math anxious individuals (50% and 48%, respectively). Factor analysis of AMAS scores, using principal component analysis by varimax rotation, yielded similar two-factor structures for both populations -- assessment and learning content -- accounting for 65.6% of the trace for bilingual AMAS scores. Statistically significant predictor variables for levels of math anxiety for the bilingual participants included (a) preparatory course enrollment (β = .236, p = .041) with those enrolled in prior preparatory courses scoring higher, (b) education major (β = .285, p = .018) with education majors scoring higher, and (c) business major (β = .252, p = .032) with business majors scoring higher. One statistically significant predictor variable emerged for monolingual students, gender (β = -.085, p = .001) with females ranking higher. Age, income, race, ethnicity, U.S. origin, science or health science majors did not emerge as statistically significant predictor variables for either group. Similarities between monolingual and bilingual participants included statistically significant negative linear correlations between AMAS scores and course grades for both bilingual (r = -.178, p = .017) and monolingual participants (r = -.203, p = .001). Differences included a statistically significant linear correlation between AMAS scores and final exam grades for monolingual participants only (r = -.253, p < .0009) despite no statistically significant difference in the strength the linear relationship of the AMAS scores and the final exam scores between groups, z = 1.35, p = .1756. The findings show that bilingual and monolingual students report math anxiety similarly and that math anxiety has similar associations with performance measures, despite differences between predictor variables. One of the first studies on the math anxiety of bilingual community college students, the results suggest recommendations for researchers and practitioners.
Resumo:
A gravidez é uma fase especial da vida, com diversas alterações nos sistemas hormonais, anatómicos, e na composição corporal da mulher. No entanto, não é claro que alterações biomecânicas tridimensionais ocorrerem. Através do acompanhamento da mulher na gravidez e pós-parto, os objetivos da presente tese foram: 1) determinar os parâmetros temporais e espaciais do ciclo da marcha; 2) descrever a cinemática angular do membro inferior; 3) calcular os momentos e potências articulares do tornozelo, joelho e coxofemoral, utilizando o cálculo por dinâmica inversa; 4) descrever as magnitudes dos picos dos momentos e potências articulares dos membros inferiores; 5) identificar possíveis diferenças entre as fases de recolha relativamente aos parâmetros biomecânicos; 6) descrever longitudinalmente a composição corporal as alterações morfológicas; 7) analisar a influência das alterações antropométricas na cinética articular. Os resultados mostram que as mulheres mantêm os parâmetros temporais e espaciais da marcha. A cinemática angular do membro inferior tem o mesmo padrão, no entanto, a magnitude de alguns picos, especialmente na bacia e coxofemoral durante a fase terminal do apoio, pré-balanço e de balanço, apresentam alterações significativas. A coxofemoral é a articulação com mais alterações na cinética articular, com um aumento da carga interna associada aos momentos articulares da coxofemoral no plano transversal. No entanto, diversos momentos e potências articulares revelam uma diminuição significativa para o final da gravidez e/ou um aumento entre alguns trimestres da gravidez e o pós-parto. Como esperado, a maioria das variáveis associadas à composição corporal e às dimensões corporais tem um aumento significativo durante a gravidez e uma diminuição no pós-parto. Os modelos desenvolvidos para prever a carga interna aplicada ao membro inferior da grávida através de variáveis antropométricas, incluem quatro modelos com variáveis associadas à quantidade de gordura, quatro modelos com variáveis associadas à massa corporal global, três modelos que incluem a massa livre de gordura, e um modelo que inclui a forma do tronco. Os altos valores do R2 ajustado, mostram que as alterações na composição corporal e morfologia, determinam em grande parte a cinética articular da mulher nesta fase particular da vida.
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O presente estudo subordinado ao tema “A influência da Ansiedade nas Competências dos Alunos da Academia Militar: Estudo de caso dos Exercício Finais - Leão 15”, tem como principal finalidade identificar e quantificar a influência da ansiedade nas competências de liderança dos Cadetes-Alunos da Academia Militar. Contribuindo assim, para o reconhecimento das competências influenciadas pela ansiedade e a sua perceção no desempenho, mais propriamente na Informação Comportamental do Aluno. No estudo foi implementado um inquérito constituído por algumas questões de caráter sociodemográfico, um questionário de competências de liderança e um questionário de medição de ansiedade – STAI. Foi aplicado a um grupo de 165 Cadetes-Alunos da Academia, sendo 95 do 4º Ano Escolar e 80 do 1º Ano Escolar. De salientar que este inquérito foi realizado duas vezes: antes e depois do Exercício Leão 15. Com base nas respostas dadas, criou-se uma base de dados em Microsoft Excel, à qual se acrescentaram as notas de Informação Comportamental dos Aluno, e procedeu-se ao seu tratamento e análise estatística, com recurso ao Statistical Package for Social Sciences. (SPSS) Dos resultados obtidos identificaram-se várias diferenças significativas entre os níveis de ansiedade e as competências de liderança, relativamente ao género, ano escolar, curso, ao desporto mais praticado e ao período em análise do Exercício Leão 15 das quais se realçam: o género feminino revelou maior índice de ansiedade no período anterior ao Exercício; o 1ºAno Escolar revelou maior índice de ansiedade estado em ambos os períodos; o curso de EXE-Engenharias revelou maior ansiedade estado e ansiedade traço no período antes do Exercício e os alunos que praticam mais frequentemente desporto coletivo revelam maior Ansiedade Estado no período depois do Exercício Leão 15. Assinalaram-se ainda correlações significativas entre a ansiedade, as competências de liderança e a nota da Informação Comportamental dos Aluno com valores mais elevados nas seguintes: “trabalho de equipa e coesão”; “flexibilidade e adaptabilidade”; “autocontrolo” e “influência e referência”. Com o objetivo de procurar identificar e quantificar as competências mais influenciadas pela ansiedade, concluiu-se que as médias de ansiedade como variável preditora é maior nas competências: “flexibilidade e adaptabilidade”, “capacidade de resolver problemas”, “reconhecimento, feedback positivo e valorização”, “aptidão técnico profissional”, “gestão de conflitos e negociação”, “transparência”, “comunicação assertiva”, “comunicação” e “relações interpessoais”.