A longevidade é uma característica relacionada à lucratividade da atividade leiteira. Contudo, sua seleção em rebanhos de vacas Holandesas no Brasil ainda é pouco considerada. Objetivou-se determinar os fatores não genéticos que influenciam a longevidade funcional em vacas Holandesas no Brasil, bem como estimar os parâmetros genéticos e conhecer a contribuição das características de tipo e da contagem de células somáticas (CCS) sobre o risco relativo de descarte das vacas. Utilizou-se um modelo de riscos proporcionais Weibull estratificado. Os efeitos fixos foram independentes do tempo, como a idade ao primeiro parto, e dependentes do tempo, como o efeito da região por ano de parto, classes de produção de leite por ano de parto dentro de rebanho, classes de percentagem de proteína e gordura dentro de rebanho, classes de produção de leite por número de lactações dentro de rebanho e variação nas classes de tamanho de rebanho. Os efeitos aleatórios foram: rebanho-ano, touro e de touro-avô materno. O risco de descarte aumentou com a idade ao primeiro parto, com o tamanho do rebanho, com o número de lactações e com o estágio de lactação. A produção de leite apresentou maior efeito sobre o risco de descarte. Vacas de baixa produção de leite, gordura e proteína apresentaram maior probabilidade de descarte em comparação à classe mediana. Vacas pertencentes às regiões do Paraná e São Paulo permaneceram mais tempo no rebanho do que as vacas de outras regiões. Os valores de h² variam de 7,8% a 6,1% para a h² equivalente e a efetiva, respectivamente. Observou-se tendência genética positiva para a longevidade. As características de tipo, escore final, angularidade, nivelamento da linha superior, textura do úbere e ligamento suspensório foram as características que se apresentaram mais relacionadas com a longevidade funcional. Foram observadas diferenças no risco de descarte dependendo do número de vacas classificadas para tipo dentro de rebanho. Até a 4ª lactação, o risco de descarte foi menor para vacas com baixa CCS em comparação a vacas da classe mediana. Já para vacas na 5ª lactação, a alta CCS conduziu ao menor risco de descarte. A rotina de avaliação genética é necessária para melhorar a duração da vida produtiva de vacas da raça Holandesa no Brasil. Características preditivas, tais como escore final, angularidade, nivelamento da linha superior, textura do úbere, ligamento suspensório e a CCS podem ser utilizadas para aumentar a confiabilidade dos valores genéticos dos touros para longevidade funcional. / Longevity is a trait related to the profitability of dairy activity. However, its selection in Brazilian Holstein herds is still little considered. The aim of this study was to determine the non-genetic factors that influence functional longevity in Holstein cows in Brazil, as well as to estimate the genetic parameters and the contribution of somatic cell score (SCS) and type traits on the relative culling risk of cows. A piecewise Weibullproportional hazard model was used. The fixed effects were time-independent, as age at first calving, and time-dependent, as the interaction effects of region by year of calving, milk production class by year of calving within herd, within herd milk production class by lactation number, within herd fat and protein content, and variation in herd size class. The random effects were herd-year effect, additive genetic contribution from the sire and maternal grandsire of the cow. The relative risk increased with age at first calving, lactation number by stage of lactation, and herd size but lower risks were observed when herd size was increasing or decreasing, compared to stable herds. Milk production had a greater effect on the risk of culling. The relative risk increased as milk production, protein and fat decreased, but to a lesser extent for protein and fat compared to milk yield. Cows from Paraná and São Paulo regions remained longer in the herd than cows from the other regions. The h² values varied from 7.8% to 6.1% for equivalent and effective h², respectively. A positive genetic trend of functional longevity was observed. The type traits, final score, angularity, top line, udder texture and suspensory ligament showed the strongest relationship with productive life. Differences in risk of culling were observed depending on the fraction of type-scored animals within a herd. The absence of type trait phenotypes was associated with a strong increase of culling risk for the cows. The impact of SCS on longevity was high in cows from 1st to 4th lactation with high SCS. Interestingly, for 5th lactation, cows with lower SCS have higher culling risk compared to cows with higher SCS. A routine of genetic evaluation is necessary to improve length of productive life of Brazilian Holsteins under local conditions. The use of early predictors correlated with longevity, as final score, angularity, top line, udder texture, suspensory ligament and SCS, may be recommended to increase the reliability of sires’ estimated breeding values for functional longevity.

Esta dissertação compreende um estudo da eficiência de estimadores dos parâmetros no modelo funcional com erro nas variáveis, com repetições para contornar o problema de falta de identificação. Nela, discute-se os procedimentos baseados nos métodos de máxima verossimilhança e escore corrigido. As estimativas obtidas pelos dois métodos levam a resultados similares. / This work is concerned with a study on the efficiency of parameter estimates in the functional linear relashionship with constant variances. Where the lack of identification is resolved of by considering replications. Estimation is dealt with by using maximum likelihood and the corrected score approach. Comparisons between the approaches are illustrated by using simulated data.

Introdução: O Escore de Alerta Precoce Modificado (MEWS) foi desenvolvido para identificação de pacientes em deterioração clínica. O objetivo foi avaliar o desempenho deste escore em enfermaria de hospital público brasileiro. Método: Parâmetros do MEWS (pressão arterial sistólica, frequência cardíaca, frequência respiratória, temperatura e nível de consciência) foram avaliados de 6/6 horas. Os seguintes eventos foram registrados: óbito, parada cardiorrespiratória e transferência para terapia intensiva. Resultados: Foram incluídos 300 pacientes (57±18 anos, sexo masculino: 65%). Observou-se número crescente de eventos combinados de acordo com o maior valor do escore (00%;00%;01%; 09%;19%;28%;89%, respectivamente para os MEWS 0;1;2;3;4;5 e 6; p<0,0001). MEWS>=4 foi o ponto de corte mais adequado para predição destes eventos (sensibilidade:87%, especificidade:85% e acurácia:0,86). Conclusões: MEWS mensura adequadamente a ocorrência de eventos graves em pacientes hospitalizados em enfermaria de um hospital público brasileiro. MEWS>=4 parece ser o ponto de corte mais adequado para predição destes eventos. / Introduction: The Modified Early Warning Score (MEWS) was developed for identification of patients in clinical deterioration. The objective was to evaluate the performance of this score in a Brazilian public hospital ward. Method: MEWS parameters (systolic blood pressure, heart rate, respiratory rate, temperature and level of consciousness) were evaluated 6/6 hours. The following events were recorded: death, cardiorespiratory arrest and transfer to intensive care. Results: 300 patients (57 ± 18 years old, male: 65%) were included. We observed a growing number of events combined according to the highest score (00%, 00%, 01%, 09%, 19%, 28%, 89%, respectively for the MEWS 0; 1; 2; 3; 4, 5 and 6, p <0.0001). MEWS>=4 was the most appropriate cutoff point for prediction of these events (sensitivity: 87%, specificity: 85% and accuracy: 0.86). Conclusions: MEWS adequately measures the occurrence of serious events in patients hospitalized in a ward of a Brazilian public hospital. MEWS>=4 seems to be the most appropriate cutoff point for predicting these events.

The purpose of this study was to develop, digitally record, evaluate, and psychometrically equate a set of Arabic monosyllabic word lists to use in the measurement of the word recognition score. Familiar Arabic monosyllabic words were digitally recorded by a native male talker from Jordan who was judged to have a standard Arabic dialect. Twenty native Arabic participants with normal hearing were used as subjects to determine the percentage of correct word recognition for each word at 10 intensity levels ranging from -5 to 40 dB HL in 5 dB increments. The monosyllabic word data were analyzed using logistic regression. The words producing the steepest psychometric function were included in the final word lists. Four lists of 50 words each were created and eight half-lists (25 words each) were created from the four lists. A Chi-square analysis was performed, revealing no statistical differences among the lists and half-lists. The mean monosyllabic psychometric function slopes at 50% for lists and half-lists were 4.8%/dB.

No description available.

Cystic fibrosis (CF) is the most common life-restricting, genetically inherited disease among Caucasians affecting approximately 30,000 people in the United States. Lung disease is the major cause of morbidity and mortality in CF. A number of oral, inhaled, and intravenous therapies are available to combat CF lung disease. Of these, this research project focused on inhaled dornase alfa, oral azithromycin, inhaled tobramycin, and inhaled aztreonam. Data to address three research aims were requested and obtained from the Cystic Fibrosis Foundation Patient Registry (CFFPR). The first aim examined the use of inhaled dornase alfa in younger children with CF. With no clinical efficacy data of dornase alfa in children ≤ 6 years of age, the study utilized subsequent forced expiratory volume in 1 second (FEV₁) measured between 6 - 7 years of age, to assess the effectiveness of long-term dornase alfa use ≤ 6 years of age. Propensity score methods were used to reduce the likelihood of treatment indication bias. The results suggested that receiving treatment with dornase alfa before 6 years of age did not improve FEV₁ between 6 - 7 years. Unmeasured covariates leading to treatment indication bias were likely one of the key explanations for these results. Additionally, lack of a more sensitive outcome than FEV₁ to assess lung function in young patients with early lung damage was thought to be another reason for the failure to reject the null hypothesis. The second aim assessed the long-term clinical effectiveness of chronic azithromycin use on the rate of FEV₁ decline in CF patients between 6 - 20 years of age. This study was novel in that the rate of FEV₁ decline, rather than change in FEV₁ from baseline, was the primary outcome, which was characterized using propensity score matching followed by a linear mixed model analysis. The results of the analysis suggested that the rate of FEV₁ decline was slower in patients who did not receive chronic treatment with azithromycin. Treatment indication bias was thought to play an important role in the direction of the association between treatment and outcome. Associations between FEV₁ % predicted and many of the other study variables included in the analysis were consistent with previous studies. The final aim compared the clinical effectiveness of a combination of inhaled tobramycin and aztreonam with inhaled tobramycin alone on the rate of FEV₁ decline in CF patients between 6 - 20 years of age. This aim was novel in that the effect of this combination treatment on rate of decline in FEV₁ has never been assessed. A linear mixed model analysis was used after matching patients in the two treatment groups on their propensity scores. Once again, the results were contrary to the alternative hypothesis with the combination group having a steeper rate of FEV₁ decline than the group that was treated with tobramycin alone. An important reason for this result was thought to be unresolved treatment indication bias that could not be eliminated even with the use of the propensity score methods used to test the associated hypothesis. The use of validated methods of analysis, i.e., propensity scores, to counter treatment indication bias using the largest available observational dataset for CF, was one of the key strengths of this study. Moreover, this study highlighted important weaknesses in the CFFPR with regards to lack of data on patient and physician-level variables - an area of active interest for the Cystic Fibrosis Foundation.

The purposes of the study were to compare the relative performances of three fixed item parameter calibration methods (FIPC) in item and ability parameter estimation and to examine how the ability estimates obtained from these different methods affect interpretations using reported scales of different lengths. Through a simulation design, the study was divided into two stages. The first stage was the calibration stage, where the parameters of pretest items were estimated. This stage investigated the accuracy of item parameter estimates and the recovery of the underlying ability distributions for different sample sizes, different numbers of pretest items, and different types of ability distributions under the three-parameter logistic model (3PL). The second stage was the operational stage, where the estimated parameters of the pretest items were put on operational forms and were used to score examinees. The second stage investigated the effect of item parameter estimation had on the ability estimation and reported scores for the new test forms. It was found that the item parameters estimated from the three FIPC methods showed subtle differences, but the results of the DeMars method were closer to those of the separate calibration with linking method than to the FIPC with simple-prior update and FIPC with iterative prior update methods, while the FIPC with simple-prior update and FIPC with iterative prior update methods performed similarly. Regarding the experimental factors that were manipulated in the simulation, the study found that the sample size influenced the estimation of item parameters. The effect of the number of pretest items on estimation of item parameters was strong but ambiguous, likely because the effect was confounded by changes of both the number of the pretest items and the characteristics of the pretest items among the item sets. The effect of ability distributions on estimation of item parameters was not as evident as the effect of the other two factors. After the pretest items were calibrated, the parameter estimates of these items were put into operational use. The abilities of the examinees were then estimated based on the examinees’ response to the existing operational items and the new items (previously called pretest items), of which the item parameters were estimated under different conditions. This study found that there were high correlations between the ability estimates and the true abilities of the examinees when forms containing pretest items calibrated using any of the three FIPC methods. The results suggested that all three FIPC methods were similarly competent in estimating parameters of the items, leading to satisfying determination of the examinees’ abilities. When considering the scale scores, because the estimated abilities were very similar, there were small differences among the scaled scores on the same scale; the relative frequency of examinees classified into performance categories and the classification consistency index also showed the interpretation of reported scores across scales were similar. The study provided a comprehensive comparison on the use of FIPC methods in parameter estimation. It was hoped that this study would help the practitioners choose among the methods according to the needs of the testing programs. When ability estimates were linearly transformed into scale scores, the lengths of scales did not affect the statistical properties of scores, however, they may impact how the scores are subjectively perceived by stakeholders and therefore should be carefully selected.

College decisions are often the result of a variety of influences related to student background characteristics, academic characteristics, college preferences and college aspirations. College counselors recommend that students choose a variety of schools, especially schools where the general student body matches the academic achievement of students. These types of schools are generally referred to as match schools. This thesis examined the initial college decisions of high school students in a large Midwestern state, who were an academic match for selective and highly selective schools by observing the student characteristics that were most influential in predicting college matching for students’ initial first choice institution. This thesis also observed college enrollment among students who chose a match school as their first choice institution, college matching over a time period from 1992 to 2013, and college matching after the implementation of a state initiative designed to help students apply for college. Logistic regression along with descriptive statistics were used as the primary analyses for college matching. Results from these analyses showed that students belonging to underrepresented minority groups had odds of college matching for their first choice institution that were significantly greater than white students. Students whose parents earned at least a bachelor’s degree had odds that were significantly greater than students whose parents had not earned a bachelor’s degree. Also, students whose coursework included calculus and physics, and students who planned to earn a graduate degree had significantly greater odds of matching on their first choice institution than students who were not a part of these respective groups. Among students in the sample who chose a match school for their first choice institution, students who had at least one parent earn up to a bachelor’s degree were significantly more likely to enroll in a match school. Also, the percentage of students at a single high school who were eligible for free and reduced lunch were negatively associated with the odds of students enrolling in a match school. To observe score sending among students to their first choice institution over time an additional variable, “year” was added to the logistic regression model to compare the years of 2000, 2008 and 2013 to 1992. The results of this logistic regression analysis showed that students’ odds of choosing a match school for their first choice institution were significantly lower in 2008 and 2013 than in 1992. College matching for students who attended high schools serviced by the state initiative were compared using the percentage differences in college matching before and after the implementation of the program. However, results could not be interpreted with certainty due to the small size of the sample.

Equating is a statistical process used to accomplish score comparability so that the scores from the different test forms can be used interchangeably. One of the most widely used equating procedures is unidimensional item response theory (UIRT) equating, which requires a set of assumptions about the data structure. In particular, the essence of UIRT rests on the unidimensionality assumption, which requires that a test measures only a single ability. However, this assumption is not likely to be fulfilled for many real data such as mixed-format tests or tests composed of several content subdomains: failure to satisfy the assumption threatens the accuracy of the estimated equating relationships. The main purpose of this dissertation was to contribute to the literature on multidimensional item response theory (MIRT) equating by developing a theoretical and conceptual framework for true-score equating using a simple-structure MIRT model (SS-MIRT). SS-MIRT has several advantages over other complex MIRT models such as improved efficiency in estimation and a straightforward interpretability. In this dissertation, the performance of the SS-MIRT true-score equating procedure (SMT) was examined and evaluated through four studies using different data types: (1) real data, (2) simulated data, (3) pseudo forms data, and (4) intact single form data with identity equating. Besides SMT, four competitors were included in the analyses in order to assess the relative benefits of SMT over the other procedures: (a) equipercentile equating with presmoothing, (b) UIRT true-score equating, (c) UIRT observed-score equating, and (d) SS-MIRT observed-score equating. In general, the proposed SMT procedure behaved similarly to the existing procedures. Also, SMT showed more accurate equating results compared to the traditional UIRT equating. Better performance of SMT over UIRT true-score equating was consistently observed across the three studies that employed different criterion relationships with different datasets, which strongly supports the benefit of a multidimensional approach to equating with multidimensional data.

Carry-over of force production symmetry in athletes of differing strength levels. J Strength Cond Res 29(11): 3188–3196, 2015—This study sought to determine the level of association between bilateral force production symmetry assessment methods (standing weight distribution [WtD], unloaded and lightly loaded jumps, and isometric strength) and to determine whether the amount of symmetry carry-over between these tasks differs for strong and weak athletes. Subjects for this study included male (n = 31) and female (n = 32) athletes from National Collegiate Athletic Association Division I sports. Athletes performed WtD, unloaded and lightly loaded (20 kg) static and countermovement jumps, and isometric midthigh pull (IMTP) assessments on 2 adjacent force plates. Ground reaction force data were used to calculate symmetry variables and performance-related variables. Using Pearson zero order correlations, evaluations of the amount of symmetry carry-over were made. Weight distribution correlated strongly with jump peak force (PF) (r = 0.628–0.664). Strong relationships were also observed between loading conditions for jump variables (r = 0.568–0.957) as were the relationships between jump types for PF, peak power, and net impulse (r = 0.506–0.834). Based on the pooled sample, there was a lack of association between IMTP and WtD for jump symmetry variables. However, when examining strong and weak groups, rate of force development showed moderate to strong symmetry carry-over in the strongest athletes (r = 0.416–0.589). Stronger athletes appear to display similar explosive strength symmetry characteristics in dynamic and isometric assessments, unlike weaker athletes. Strength seems to influence the amount of force production symmetry carry-over between bilateral assessments. There may be optimal loads and variables for symmetry assessment, but these may differ based on population characteristics.