Hypertension occurs in nearly 10% of pregnancies, and is associated with infant and maternal morbidity and mortality. Prior studies of non-pregnant adults have demonstrated the effectiveness of a variety of relaxation therapies in reducing blood pressure. A pilot randomized controlled trial was conducted, the purposes of which were 1) to provide preliminary evidence regarding the usefulness of guided imagery (GI) in reducing blood pressure in hypertensive pregnant women, and 2) to answer feasibility questions for a larger trial. Pregnant women with hypertension prior to 37 weeks gestation (n = 69) were randomized to either 15-minute periods of guided imagery (n = 34), or of quiet rest (QR) (n = 35), twice daily for four weeks or until delivery, whichever came first. Daytime ambulatory mean arterial pressure (MAP), systolic and diastolic blood pressures, anxiety, rest and GI use were measured weekly, to a maximum of four weeks. Sixty women completed at least one week in the study; 46.4% completed four weeks. Compliance was excellent. Intention to treat analysis was used. In the unadjusted analysis, women allocated to GI had significantly lower average daytime ambulatory mean MAP elevations from baseline to their last week of study participation than women allocated to quiet rest (GI: M = 1.58 mmHg, SD = 7.63; QR: M = 5.93 mmHg, SD = 6.55; t = 2.36, p = .02). However, the effect was no longer statistically significant (p = 0.14) when adjusted for baseline mean arterial pressure and gestation. There was no statistically significant difference in the numbers of women who were prescribed antihypertensive medication after randomization (GI: n = 16, QR: n = 13, X2 = 0.74, p = .46). There was also no evidence of an effect of guided imagery on anxiety. Nearly 90% (n = 26) of the guided imagery group indicated they would use it again, either in a subsequent pregnancy or during stressful life events. Given the ease of use, low cost, acceptability to women, and lack of risk of guided imagery, an adequately-powered randomized controlled trial is warranted.

Leadership is important to quality improvement initiatives in healthcare. However, few studies have evaluated leadership interventions to enhance nurses’ use of guideline recommendations in the field of knowledge translation. Purpose: To develop and evaluate an intervention designed to operationalize a leadership strategy composed of relations, change, and task-orientated leadership behaviours, and to examine its influence on nurses’ use of guideline recommendations in home-care nursing. Design: Sequential mixed methods pilot study with post-only cluster randomized controlled trial. Methods Phase I: Intervention Development 1. A participatory approach was used at a community healthcare organization with 23 units across the province of Ontario, Canada. The guideline selected was developed by the Registered Nurses’ Association of Ontario for the assessment and management of foot ulcers for people with diabetes. 2. Integrative literature review, qualitative interviews, and baseline chart audits were conducted. 3. Four units were randomized to control or experimental groups. 4. Clinical and management leadership teams participated in a 12-week intervention consisting of printed materials, interactive workshop, and teleconferences. Participants received summarized chart audit data, identified priority indicators for change, and created a team leadership action plan to address barriers and influence guideline use. Phase II: Evaluation 5. Chart audits compared differences in nursing process and patient outcomes. Primary outcome: eight-item nursing assessment score. 6. Qualitative interviews evaluated the intervention and leadership behaviours. Results: No significant difference was found in the primary outcome. A significant difference was observed in nurses’ documentation of five priority indicators chosen by the experimental groups (p=.02). Gaps in care included: 53%, 76%, and 94% of patients not assessed for ulcer depth, foot circulation, or neuropathy (respectively); 75% and 93% did not receive wound debridement or hydrogel dressings. Receiving data to identify priority indicators for change and developing a leadership action plan were reported as useful to guideline implementation. The experimental group described using more relations-oriented leadership behaviours conducting audit and feedback, and sending reminders. Conclusion: Findings from this pilot study suggest that leadership is a team process involving relations, change, and task-oriented behaviours enacted by managers and clinical leaders. A leadership model is proposed as a beginning taxonomy to inform future leadership intervention studies.

Ad hoc networks and bluetooth systems operating over the unlicensed ISM band are in-stances of decentralized wireless networks. By definition, a decentralized network is com-posed of separate transmitter-receiver pairs where there is no central controller to assign the resources to the users. As such, resource allocation must be performed locally at each node. Users are anonymous to each other, i.e., they are not aware of each other's code-books. This implies that multiuser detection is not possible and users treat each other as noise. Multiuser interference is known to be the main factor that limits the achievable rates in such networks particularly in the high Signal-to-Noise Ratio (SNR) regime. Therefore, all users must follow a distributed signaling scheme such that the destructive effect of interference on each user is minimized, while the resources are fairly shared. In chapter 2 we consider a decentralized wireless communication network with a fixed number of frequency sub-bands to be shared among several transmitter-receiver pairs. It is assumed that the number of active users is a realization of a random variable with a given probability mass function. Moreover, users are unaware of each other's codebooks and hence, no multiuser detection is possible. We propose a randomized Frequency Hopping (FH) scheme in which each transmitter randomly hops over a subset of sub-bands from transmission slot to transmission slot. Assuming all users transmit Gaussian signals, the distribution of the noise plus interference is mixed Gaussian, which makes calculation of the mutual information between the transmitted and received signals of each user intractable. We derive lower and upper bounds on the mutual information of each user and demonstrate that, for large SNR values, the two bounds coincide. This observation enables us to compute the sum multiplexing gain of the system and obtain the optimum hopping strategy for maximizing this quantity. We compare the performance of the FH system with that of the Frequency Division (FD) system in terms of the following performance measures: average sum multiplexing gain and average minimum multiplexing gain per user. We show that (depending on the probability mass function of the number of active users) the FH system can offer a significant improvement in terms of the aforementioned measures. In the sequel, we consider a scenario where the transmitters are unaware of the number of active users in the network as well as the channel gains. Developing a new upper bound on the differential entropy of a mixed Gaussian random vector and using entropy power inequality, we obtain lower bounds on the maximum transmission rate per user to ensure a specified outage probability at a given SNR level. We demonstrate that the so-called outage capacity can be considerably higher in the FH scheme than in the FD scenario for reasonable distributions on the number of active users. This guarantees a higher spectral efficiency in FH compared to FD. Chapter 3 addresses spectral efficiency in decentralized wireless networks of separate transmitter-receiver pairs by generalizing the ideas developed in chapter 2. Motivated by random spreading in Code Division Multiple Access (CDMA), a signaling scheme is introduced where each user's code-book consists of two groups of codewords, referred to as signal codewords and signature codewords. Each signal codeword is a sequence of independent Gaussian random variables and each signature codeword is a sequence of independent random vectors constructed over a globally known alphabet. Using a conditional entropy power inequality and a key upper bound on the differential entropy of a mixed Gaussian random vector, we develop an inner bound on the capacity region of the decentralized network. To guarantee consistency and fairness, each user designs its signature codewords based on maximizing the average (with respect to a globally known distribution on the channel gains) of the achievable rate per user. It is demonstrated how the Sum Multiplexing Gain (SMG) in the network (regardless of the number of users) can be made arbitrarily close to the SMG of a centralized network with an orthogonal scheme such as Time Division (TD). An interesting observation is that in general the elements of the vectors in a signature codeword must not be equiprobable over the underlying alphabet in contrast to the use of binary Pseudo-random Noise (PN) signatures in randomly spread CDMA where the chip elements are +1 or -1 with equal probability. The main reason for this phenomenon is the interplay between two factors appearing in the expression of the achievable rate, i.e., multiplexing gain and the so-called interference entropy factor. In the sequel, invoking an information theoretic extremal inequality, we present an optimality result by showing that in randomized frequency hopping which is the main idea in the prevailing bluetooth devices in decentralized networks, transmission of independent signals in consecutive transmission slots is in general suboptimal regardless of the distribution of the signals. Finally, chapter 4 addresses a decentralized Gaussian interference channel consisting of two block-asynchronous transmitter-receiver pairs. We consider a scenario where the rate of data arrival at the encoders is considerably low and codewords of each user are transmitted at random instants depending on the availability of enough data for transmission. This makes the transmitted signals by each user look like scattered bursts along the time axis. Users are block-asynchronous meaning there exists a delay between their transmitted signal bursts. The proposed model for asynchrony assumes the starting point of an interference burst is uniformly distributed along the transmitted codeword of any user. There is also the possibility that each user does not experience interference on a transmitted codeword at all. Due to the randomness of delay, the channels are non-ergodic in the sense that the transmitters are unaware of the location of interference bursts along their transmitted codewords. In the proposed scheme, upon availability of enough data in its queue, each user follows a locally Randomized Masking (RM) strategy where the transmitter quits transmitting the Gaussian symbols in its codeword independently from symbol interval to symbol interval. An upper bound on the probability of outage per user is developed using entropy power inequality and a key upper bound on the differential entropy of a mixed Gaussian random variable. It is shown that by adopting the RM scheme, the probability of outage is considerably less than the case where both users transmit the Gaussian symbols in their codewords in consecutive symbol intervals, referred to as Continuous Transmission (CT).

<p>Uncovering the DNA regulatory logic in complex organisms has been one of the important goals of modern biology in the post-genomic era. The sequencing of multiple genomes in combination with the advent of DNA microarrays and, more recently, of massively parallel high-throughput sequencing technologies has made possible the adoption of a global perspective to the inference of the regulatory rules governing the context-specific interpretation of the genetic code that complements the more focused classical experimental approaches. Extracting useful information and managing the complexity resulting from the sheer volume and the high-dimensionality of the data produced by these genomic assays has emerged as a major challenge which we attempt to address in this work by developing computational methods and tools, specifically designed for the study of the gene regulatory processes in this new global genomic context. </p><p>First, we focus on the genome-wide discovery of physical interactions between regulatory sequence regions and their cognate proteins at both the DNA and RNA level. We present a motif analysis framework that leverages the genome-wide</p><p>evidence for sequence-specific interactions between trans-acting factors and their preferred cis-acting regulatory regions. The utility of the proposed framework is demonstarted on DNA and RNA cross-linking high-throughput data.</p><p>A second goal of this thesis is the development of scalable approaches to dimension reduction based on spectral decomposition and their application to the study of population structure in massive high-dimensional genetic data sets. We have developed computational tools and have performed theoretical and empirical analyses of their statistical properties with particular emphasis on the analysis of the individual genetic variation measured by Single Nucleotide Polymorphism (SNP) microrarrays.</p> / Dissertation

We develop two algorithms for important problems in mobile ad hoc networks (MANETs). A MANET is a collection of mobile processors (“nodes”) which communicate via message passing over wireless links. Each node can communicate directly with other nodes within a speci&#64257;ed transmission radius; other communication is accomplished via message relay. Communication links may go up and down in a MANET (as nodes move toward or away from each other); thus, the MANET can consist of multiple connected components, and connected components can split and merge over time. We &#64257;rst present a deterministic leader election algorithm for asynchronous MANETs along with a correctness proof for it. Our work involves substantial modi&#64257;cations of an existing algorithm and its proof, and we adapt the existing algorithm to the asynchronous environment. Our algorithm’s running time and message complexity compare favorably with existing algorithms for leader election in MANETs. Second, many algorithms for MANETs require or can bene&#64257;t from knowledge about the size of the network in terms of the number of processors. As such, we present an algorithm to approximately determine the size of a MANET. While the algorithm’s approximations of network size are only rough ones, the algorithm has the important qualities of requiring little communication overhead and being tolerant of link failures.

In addition to the increased risk they face for social and academic problems, adolescents with Attention-Deficit/Hyperactivity Disorder (ADHD) must also contend with stigma attached to the disorder. For instance, youth prefer greater social distance from students described with ADHD symptoms than from peers with asthma (Walker, Coleman, Lee, Squire, & Friesen, 2008), and adolescents are also reluctant to engage in activities (e.g., go to the movies, study together) with a peer described with ADHD symptoms compared to peers described as obese or autistic (Law, Sinclair, & Fraser, 2007). Familiarity with individuals diagnosed with ADHD may influence adolescents' perceptions of their peers with ADHD, but the extant research on this relationship in adolescents is limited and mixed. The purpose of this study was to investigate middle school students' familiarity with ADHD, their willingness to engage in activities with a peer exhibiting ADHD symptoms, and how familiarity impacts their willingness to engage in a variety of activities with that peer. A sample of middle school students (N = 176) completed self-report measures of contact with ADHD and willingness to engage with a peer described in a vignette. Participants were randomly assigned vignettes describing either a peer displaying ADHD symptoms or a typical peer, employing a true experimental design. Middle school students expressed greater willingness to engage with a typical peer than one with ADHD symptoms overall. However, a significant difference (p < .05) was found only for academic activities, and not for social and recreational activities. This difference was present regardless of the inclusion of positive characteristics in the description of the peer with ADHD, suggesting that it is something about ADHD symptoms leading to middle school students' reluctance, not simply the lack of appealing characteristics. Additionally, approximately 70% of middle school students indicated some contact with ADHD, although familiarity with ADHD was not found to predict participants' willingness to engage in activities with a peer with ADHD symptoms. Implications for school psychologists and directions for future research are discussed.

Abstract Despite documented health benefits, most breast cancer survivors (BCS) do not meet physical activity (PA) guidelines. Hence, evaluating diverse intervention approaches to promote PA in BCS is imperative. Motivational Interviewing (MI) offers a non-prescriptive, client-centered approach to PA promotion that has not been adequately evaluated in BCS. In this randomized-controlled trial, 66 Stage 0-IIIa BCS within three years post-treatment, insufficiently active and contemplating increasing PA were randomly assigned to a MI intervention or an active control condition. The MI intervention implemented motivational and behavior change strategies consistent with MI principles. The active control condition provided education and prescriptive recommendations on diet, PA, and stress management. Participants completed two in-person and one phone-based sessions over 4 weeks. Outcomes were assessed at baseline, 6-week, and 12-week follow-up. The primary outcome was efficacy of the MI intervention to promote PA. Contrary to the hypothesis that the MI intervention would be superior, PA improvements were evident for both groups, with 60% of all participants meeting PA guidelines at 12-week follow-up. Secondary outcomes involved intervention effects on depressive symptoms, fatigue, vigor, and aerobic fitness. Contrary to hypotheses, improvements in secondary outcomes were evident for both groups. Exploratory moderation analyses yielded no group differences in PA outcomes based on baseline activity level, perceived stress, age, or body mass index. Exploratory mediation analyses indicated that the relationships between group assignment and change in secondary outcomes were not mediated by change in PA. In analyses of the combined sample, higher baseline aerobic fitness predicted greater improvement in PA over time. Overall, results suggest that diverse intervention approaches can help promote PA in BCS. Future research should evaluate long-term maintenance of gains and theoretical mechanisms of the intervention effect.

The experience of stress may contribute to increased food consumption and selection of unhealthy food options. Resource depletion theory suggests stress temporarily depletes resources needed to regulate behavior. Depletions of self-control may result in subsequent failure to regulate eating behaviors, which is particularly salient in restrained eaters. Restraint theory posits people high in dietary restraint require significant effort to control eating. Emotional eating theory further suggests palatable foods may be used to regulate emotional stress reactions. Relaxation exercises to mitigate stress reactions are recommended in eating and weight management programs, but lack quality scientific support. The current study examined the efficacy of a brief relaxation intervention on stress-related eating in a sample of at-risk women. Self-regulatory resources and affect were tested as mechanisms of action. A sample of 139 women high in dietary restraint completed a stress-task and were subsequently randomized to a relaxation intervention or control group. Participants were presented with foods varied on taste and fat content. Affect, subjective relaxation, and self-regulatory resources were measured at baseline, pre-, and post-intervention. Participation in a relaxation intervention resulted in significantly less food consumption (p < .05), with a trend toward lower consumption of sweet food (p = .05), compared to controls. Multiple mediator models examining proposed indirect effects of group on eating outcomes were not supported, with the exception of change in subjective relaxation as a significant indirect effect for high-fat food consumption. This study is the first to provide experimental evidence of the efficacy of relaxation in mitigating the effects of stress on eating. Limitations, implications, and future research directions are discussed.

Significance: Complementary and alternative therapies (CAM) are widely used however the efficacy of many CAM therapies for specific diseases has yet to be verified. Massage therapy, specifically back massage, used to assist in the management of elevated blood pressure is one such unverified therapy. A pilot study completed in 2002 resulted in significant changes in blood pressure using a repeated application of the 10 minute back massage. Research Aims: This study, evolving from a psychophysiology framework, aimed to determine the long term efficacy of a back massage treatment and possible dosage needed to effectively assist in the management of elevated blood pressure. Primary Research Hypotheses: After adjusting for covariates: A. Systolic blood pressure (SBP) and or diastolic blood pressure (DBP) would decrease significantly over time using a back massage treatment in subjects with pre-hypertension or controlled hypertension.B. There would be a significant difference in the SBP (and or DBP) changes over time using 10 applications of back massage versus five applications of back massage in the subjects with pre-hypertension and controlled hypertension.Methods: A priori power analysis determined the three groups by four time points (repeated measures) design required a sample of 45 participants. The sample of men and women, 18-75 years of age, were recruited from a university setting. Outcome Variables: Systolic Blood Pressure, Diastolic Blood Pressure Potential Covariates: Age, BMI, Medications, Years of Hypertension, Salivary cortisol, and State and Trait Personality Indicators (anger, anxiety, depression). Intervention: Group 1: Ten 10-minute back massages given three times a week for 3.5 weeks. Group 2: Five 10-minute back massages given three times a week for 1.5 weeks. Control (group 3): Ten 10-minute relaxation sessions using learned techniques for 3.5 weeks. Findings: For participants with elevated body mass index (>̲27.85) in the 10-massage group, systolic and diastolic blood pressure changed significantly over time. The dosage analysis did not clearly reveal the direction of the trends, therefore further exploration is warranted.

It is well known that incorporating auxiliary covariates in the analysis of randomized clinical trials (RCTs) can increase efficiency. Questions still remain regarding how to flexibly incorporate baseline covariates while maintaining valid inference. Recent methodological advances that use semiparametric theory to develop covariate-adjusted inference for RCTs have focused on independent outcomes. In biomedical research, however, cluster randomized trials and longitudinal studies, characterized by correlated responses, are commonly used. We develop methods that flexibly incorporate baseline covariates for efficiency improvement in randomized studies with correlated outcomes. In Chapter 1, we show how augmented estimators may be used for cluster randomized trials, in which treatments are assigned to groups of individuals. We demonstrate the potential for imbalance correction and efficiency improvement through consideration of both cluster- and individual-level covariates. To improve small-sample estimation, we consider several variance adjustments. We evaluate this approach for continuous and binary outcomes through simulation and apply it to the Young Citizens study, a cluster randomized trial of a community behavioral intervention for HIV prevention in Tanzania. Chapter 2 builds upon the previous chapter by deriving semiparametric locally efficient estimators of marginal mean treatment effects when outcomes are correlated. Estimating equations are determined by the efficient score under a mean model for marginal effects when data contain baseline covariates and exhibit correlation. Locally efficient estimators are implemented for longitudinal data with continuous outcomes and clustered data with binary outcomes. Methods are illustrated through application to AIDS Clinical Trial Group Study 398, a longitudinal randomized study that compared various protease inhibitors in HIV-positive subjects. In Chapter 3, we empirically evaluate several covariate-adjusted tests of intervention effects when baseline covariates are selected adaptively and the number of randomized units is small. We demonstrate that randomization inference preserves type I error under model selection while tests based on asymptotic theory break down. Additionally, we show that covariate adjustment typically increases power, except at extremely small sample sizes using liberal selection procedures. Properties of covariate-adjusted tests are explored for independent and multivariate outcomes. We revisit Young Citizens to provide further insight into the performance of various methods in small-sample settings.