Master of Science / Department of Statistics / Christopher I. Vahl / In the classic split-plot design where whole plots have a completely randomized design, the conventional analysis approach assumes a compound symmetry (CS) covariance structure for the errors of observation. However, often this assumption may not be true. In this report, we examine using different covariance models in PROC MIXED in the SAS system, which are widely used in the repeated measures analysis, to model the covariance structure in the split-plot data in which the simple compound symmetry assumption does not hold. The comparison of the covariance structure models in PROC MIXED and the conventional split-plot model is illustrated through a simulation study. In the example analyzed, the heterogeneous compound symmetry (CSH) covariance model has the smallest values for the Akaike and Schwarz’s Bayesian information criteria fit statistics and is therefore the best model to fit our example data.

<p>Religious faith has been identified as a protective factor against negative psychological outcomes and is associated with a range of positive mental and physical health outcomes. While religion is thought to confer psychological benefits to believers in part by enhancing emotion regulation abilities and providing faith-based regulatory methods such as religious coping, these associations have not been examined empirically. This may be due to a lack of measures that are appropriate for use in repeated measures contexts, which are needed for accurate assessment of dynamic constructs such as emotions and regulation. This study employed generalizability theory in a sample (N = 146) collected in daily dairy format over 21 days to determine the reliability of commonly used measures of religiosity and religious coping at the daily level. Once reliability was established, varying time scales were used in a multilevel modeling framework to examine the associations among intrinsic religiosity, religious coping, positive and negative affect, and difficulties in emotion regulation. Positive religious coping (PRC) measured at baseline, same day, and a 1-day lag was associated with higher levels of daily positive affect, though PRC was also associated with negative affect when measured on the same day. Negative religious coping (NRC) measured at baseline predicted lower levels of daily positive affect and was associated with higher levels of negative affect when measured on the same day and a 1-day lag. NRC was also associated with higher levels of difficulties in emotion regulation at all measurement periods, though PRC and intrinsic religiosity were not significantly associated with emotion regulation difficulties. While not associated with daily positive or negative affect, intrinsic religiosity was found to enhance the effect of positive affect inertia. These results did not support the conceptualization that religiosity broadly promotes adaptive emotion regulation, but rather that intrinsic religiosity may increase positive affect by amplifying the effects of positive affect inertia. Additional work is needed with increased measurement occasions to fully understand the temporal associations among these constructs.</p>

The medial olivocochlear reflex (MOCR) is a brainstem-mediated reflex that reduces cochlear amplifier gain when elicited by sound. The MOCR may provide benefits such as protection from acoustic trauma and improved hearing in background noise. Measurement of MOCR effects may also have clinical applications. MOCR effects can be measured using transient-evoked otoacoustic emissions (TEOAEs), as amplitudes of TEOAEs are typically reduced during MOCR activation. The primary purpose of the current study was to quantify the repeatability of MOCR effects on TEOAEs because high repeatability in a healthy population is a necessary (but not sufficient) component of a clinically-useful test. A secondary purpose was to assess the relationship between MOCR strength and speech perception in noise. Twenty-one normal hearing subjects ages 18-30 participated. TEOAEs were elicited using 35 dB sensation level (SL) clicks. The MOCR was elicited using contralateral acoustic stimulation (CAS) consisting of 35 dB SL broadband noise. Sixteen measurements were made across a 5-week period (4 visits × 4 measurements per visit). TEOAEs were bandpass filtered in 1/6-octaves from 1-2 kHz. An individualized time-frequency analysis was used to select the largest TEOAE envelope peak within a restricted time analysis window. Responses were characterized as the complex ratio of TEOAEs obtained with versus without CAS. The statistical significance of effects was assessed. Results revealed generally high levels of stability across time, as assessed by the interquartile ranges of all results and as assessed by Cronbach's alpha. Four MOCR measurements appeared to be adequate to obtain a reliable baseline measurement. Individualized time-frequency analyses were also important for obtaining reliable measurements. However, several subjects showed stable baseline measurements but unusual patterns of variability at subsequent sessions. These changes did not appear to be the result of changes in auditory status, methodological issues, or equipment issues. No significant relationship was found between MOCR strength and speech perception in noise. Results suggest that MOCR measurements are stable in most subjects when using careful measurement and analysis methods, but that further work is needed to better characterize changes in MOCR and to validate the current methodology in a larger number of subjects.

The aim of this study was to examine and compare the contribution of central neuromuscular fatigue and peripheral neuromuscular fatigue to total neuromuscular fatigue in the hemiplegic leg of people with stroke, with that of a matched control group.Study Design: This experimental study utilised a repeated measures block design.Participants: Fifteen people with chronic stroke who had mild to moderate physical disability and fifteen age, height and weight matched controls were compared.Main outcome measures: Participants physical function was evaluated using the 30s Chair Stand Test, Comfortable Paced Walking Speed and Fast Paced Walking Speed. Neuromuscular function was measured using maximal voluntary isometric contraction force and voluntary activation. Total neuromuscular fatigue, central neuromuscular fatigue and peripheral neuromuscular fatigue was measured during a 90 second sustained maximal voluntary isometric contraction of the quadriceps muscle.Results: The fatigue profile of stroke participants differed from that of control participants. Stroke participants demonstrated less total neuromuscular fatigue (U=41.00, p=.026) and less peripheral neuromuscular fatigue (U=14.00, p=.000) than the control participants. While stroke participants did demonstrate greater central neuromuscular fatigue than control participants, this finding was not statistically significant (U=80.00, p=.817).Conclusions: Statistically significant differences were found in the performance of people with mild to moderate physical disability following stroke on measures of neuromuscular fatigue when compared to age, weight and height matched healthy adults.

The aim of this study was to examine and compare the contribution of central neuromuscular fatigue and peripheral neuromuscular fatigue to total neuromuscular fatigue in the hemiplegic leg of people with stroke, with that of a matched control group.Study Design: This experimental study utilised a repeated measures block design.Participants: Fifteen people with chronic stroke who had mild to moderate physical disability and fifteen age, height and weight matched controls were compared.Main outcome measures: Participants physical function was evaluated using the 30s Chair Stand Test, Comfortable Paced Walking Speed and Fast Paced Walking Speed. Neuromuscular function was measured using maximal voluntary isometric contraction force and voluntary activation. Total neuromuscular fatigue, central neuromuscular fatigue and peripheral neuromuscular fatigue was measured during a 90 second sustained maximal voluntary isometric contraction of the quadriceps muscle.Results: The fatigue profile of stroke participants differed from that of control participants. Stroke participants demonstrated less total neuromuscular fatigue (U=41.00, p=.026) and less peripheral neuromuscular fatigue (U=14.00, p=.000) than the control participants. While stroke participants did demonstrate greater central neuromuscular fatigue than control participants, this finding was not statistically significant (U=80.00, p=.817).Conclusions: Statistically significant differences were found in the performance of people with mild to moderate physical disability following stroke on measures of neuromuscular fatigue when compared to age, weight and height matched healthy adults.

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There are surveys carried out repeatedly on the same set of units. In connection with such research, we are talking about the dependent samples. The aim and the contribution of this diploma thesis is a summary of available methods for analyzing data from dependent samples for both continuous and discrete variables. The Czech literature has been devoted to this topic only marginally. The theoretical part is divided into two main parts for two waves and for more waves of exploration, which are further divided according to the type of reference variable. The third part is devoted to the application of the theoretical information in a market research.

Long term longitudinal surveys have the advantage to enable several sampling of the studied phenomena and then, with the repeated measures obtained, find a confirmed tendency. However, these long term surveys generate large epidemiological datasets including more sources of noise than normal datasets (e.g. one single measure per observation unit) and potential correlation in the measured values. Here, we studied data from a long-term epidemiological and genetic survey of malaria disease in two family-based cohorts in Senegal, followed for 19 years (1990-2008) in Dielmo and for 16 years (1993-2008) in Ndiop. The main objectives of this work were to take into account familial relationships, repeated measures as well as effect of covariates to measure both environmental and host genetic (heritability) impacts on the outcome of infection with the malaria parasite Plasmodium falciparum, and then use findings from such analyses for linkage and association studies. The outcome of interest was the occurrence of a P. falciparum malaria attack during each trimester (PFA). The two villages were studied independently; epidemiological analyses, estimation of heritability and individual effects were then performed in each village separately. Linkage and association analyses used family-based methods (based on the original Transmission Disequilibrium Test) known to be immune from population stratification problems. Then to increase sample size for linkage and association analyses, data from the two villages were used together.

This paper reports a series of experiments designed to compare memory for multiple kinds of source information in young and older adults. The older adults in these studies were classified as having well or poorly functioning frontal lobes. In EXPERIMENTS 1-3, three different sources that provided independent cues to item information were examined using a repeated-measures design. In particular, participants' memory for voice source information, spatial source information, and temporal source information was tested in separate blocks. The results indicated that the performance of both young and older adults depended upon the type of source tested: Voice source memory was superior to spatial source and temporal source memory, which did not differ. There was also an age effect that was mediated by frontal functioning. Only the low frontal older adults showed impairments in source memory. High frontal older adults were equivalent to young. In EXPERIMENT 4, sources that provided redundant cues to item information were investigated. Voice sources and spatial sources were perfectly matched during encoding such that Voice A always came from Location 1 and Voice B always came from Location 2. When sources provided redundant information in this manner, young and high frontal older adults improved their spatial source memory by making use of redundant voice information, whereas the low frontal older adults not only performed more poorly than both young and high frontal older adults, but were unable to benefit from the redundancy. No differences in item memory were found. The findings were interpreted in terms of the executive and working memory functions involved in the integration of various contextual elements of an experience with its content.

The study of stress is limited in professional nursing, but it is nearly non-existent in professional military nursing. The purpose of this study was to explore the relationships among psychological, environmental, biological and demographic factors of stress in new Army nurses during the Army Medical Department’s 8-week Officer Basic Leadership Course (OBLC). Using a descriptive prospective, correlational repeated measures design, 33 study participants completed two psychological stress measures (Perceived Stress Scale [PSS] and the Impact of Event Scale – Revised[IES-R]), an environmental measure (Life Experiences Survey [LES]), a biologic measure (salivary cortisol) and a demographic questionnaire at three different time points during OBLC: at the beginning of OBLC, during the field training exercise and at the end of OBLC. The majority of participants were single, Caucasian females under 30 years of age with no RN experience and no deployment experience. No significant gender differences were detected among study variables. A simple (single-group) repeated measures analysis of the PSS scores, IES-R scores, and salivary cortisol was conducted using the LES score as a covariate. While the PSS scores and salivary cortisol levels did not change significantly over time, the IES-R score did change significantly over time (p = 0.001). The environmental factor (LES score) was not significant as a covariate in any of the three models. The unique baseline findings in this study may provide a springboard for further studies in stress particularly with military nurses who will eventually be deployed and experience a variety of stressful events. Longitudinal research could yield important predictive information related to how the stress response evolves over the course of one’s military career which may include frequent deployments to the combat zone.