In multi-agent Markov Decision Processes, a controllable agent must perform optimal planning in a dynamic and uncertain environment that includes another unknown and uncontrollable agent. Given a task specification for the controllable agent, its ability to complete the task can be impeded by an inaccurate model of the intent and behaviors of other agents. In this work, we introduce an active policy inference algorithm that allows a controllable agent to infer a policy of the environmental agent through interaction. Active policy inference is data-efficient and is particularly useful when data are time-consuming or costly to obtain. The controllable agent synthesizes an exploration-exploitation policy that incorporates the knowledge learned about the environment's behavior. Whenever possible, the agent also tries to elicit behavior from the other agent to improve the accuracy of the environmental model. This is done by mapping the uncertainty in the environmental model to a bonus reward, which helps elicit the most informative exploration, and allows the controllable agent to return to its main task as fast as possible. Experiments demonstrate the improved sample efficiency of active learning and the convergence of the policy for the controllable agents.

Obstacles sometimes limit enrollment in randomized clinical trials of an exper- imental product versus an active control, making it desirable to augment the ran- domized control group with historical control groups. However, bias between control groups with respect to the mean outcome could lead to spurious conclusions. Meth- ods are necessary that allow for the combination of control groups while controlling for bias. Pocock (1976) developed a Bayesian test to address this need, but it requires sub- jective specification of the variance of the bias between the randomized and historical control groups and is designed to include only a single historical control group. In the context of an actively controlled non-inferiority trial, we extend his method on three fronts. First, we replace subjective specification of the variance of the bias with empirically driven estimates. Second, we develop an adaptive design that re-powers a trial based on an interim estimate of the variance of the bias using observed data. Third, we modify the test to include multiple historical control groups. When including a single historical control group, simulations show that the true bias, if known, can be used in place of the variance of the bias, and that this estimate ivmaintains Type I Error with no loss in power as compared to using the true variance of the bias. Further, we show that using an empirical estimate of the bias to estimate the variance of bias may result in moderately inflated Type I Error, but that using a conservative estimate of the bias (the upper bound of a 90% confidence interval) maintains Type I Error. Simulations also demonstrate that using an estimate of the bias at the interim and conclusion provides designed power but may result in moder- ately inflated Type I Error. Therefore, a conservative estimate of the bias should be used at trial end when using this approach. Lastly, it is shown that if an adequate number of multiple historical control groups are available, the modified test maintains Type I Error when using bias estimates. These methods provide objective guidance on parameter estimation, but further research is necessary in order to improve power.

Doctor of Philosophy / Curriculum and Instruction Programs / Kay Ann Taylor / The purpose of this qualitative multiple participant case study was to identify the influence of social media on Saudi graduate students who are active social media users. Social media have been influencing Saudi students differently than those in other socio-cultural contexts due to the uniqueness of the Kingdom of Saudi Arabia (KSA) in terms of cultural, political, economic, and social life. This study contributes to educational technology broadly and understanding the experiences of Saudi graduate students who are active social media users specifically. This study sought to illuminate and clarify understanding of the influence of social media use on graduate students in the KSA. This study investigated the influence of social media on Saudi graduate students through the experience of six Saudi graduate students who have 200K or more followers/subscribers on YouTube, Twitter, Instagram, or Snapchat. Vygotsky-based social constructivism was used to analyze and interpret the findings of the research in an effort to understand and make sense of the impact of social media on education through the participants’ experiences as graduate students and active social media users. The significant findings of this research support social constructivism, in that learning occur through social interaction with the More Knowledgeable Other (MKO) in the Zone of Proximal Development (ZPD). The findings of the study included three emerging themes: (1) social media experience, (2) social media influence, and (3) changes brought by social media. Two categories emerged from the data under the first theme. The categories are (a) planned versus unplanned fame, and (b) social media preferred sites, activities and topics. Three categories and two sub-categories emerged from the second theme: (a) educational influence, which has two sub-categories —(i) formal teaching and learning (ii) informal learning —; (b) financial influence; and (c) gender issues in social media. The results contribute to the limited qualitative research on Saudi graduate students and social media and to the overall social constructivism research in the KSA higher education.

Background: Historically, the focus of the UK and international research exploring planned home birth decision making has been largely focused on understanding the experiences of women who decide to birth at home. As a result of high-profile research that suggests that non-OU birth locations are safe for low risk women, there has been a recent shift in focus resulting in research studies that aim to increase the rates of planned home birth, or more often the rates of all non-obstetric unit birth within the UK. However, despite this increased level of attention, the rate of home birth remains stubbornly low. Whilst there is some research to indicate why this might be the case, research that sheds a new light on the issue, and that develops an evidence base for new interventions is required. This thesis illuminates the factors that need to be considered in order to increase women’s abilities to make an informed decision about planned birth. Methodology: A pragmatic approach, using mixed methods, was used to explore the current way that we offer planned home birth to maternity service users, and to ultimately make suggestions about how this could be improved. The following studies have been undertaken: Study 1: Initial exploratory study: The case notes of one hundred and sixty nine women, from one health board and who had planned to birth at home, were audited. Non-participant observation of birth planning meetings at thirty-six weeks gestation were undertaken with seven community midwife and low-risk women dyads. These were followed by individual semi-structured interviews with the participants. Study 2: Scoping review: Qualitative and quantitative research, and non-research based literature, were analysed to produce a qualitative review of planned home birth decision making. Study 3: Active offer of planned home birth concept analysis The findings of the initial exploratory study and the scoping review, in addition to active offer literature that is predominantly applied to support the provision of services within minority official languages, were used to create an active offer of planned home birth. Study 4: Workshop study testing the findings of the concept analysis Narrative based exercises were used to explore the concept analysis findings with twenty previous service users who had birthed at home, nine previous service users who had chosen an institutional birth, and fourteen community midwives. Findings: Women will either take a ‘passive’ or ‘active’ approach to the offer of planned home birth, with a passive approach likely where no motivation for an active approach has been provided. Where a woman takes a passive approach, her ability to make an informed decision about planned home birth will depend on an active offer being made by her midwife. This will be most effective when it is supported by a midwife’s employing organisation. The findings of this thesis suggest that a two stage active offer of planned home birth (AOPHB) process, consisting of ‘Creating the conditions’ and ‘Positive reinforcement’ stages, can be used to underpin the offer of planned home birth. Discussion: There has previously been minimal understanding of how to facilitate the home birth decision making process, and a passive offer is routinely provided to women in the UK. The proposed two-stage AOPHB process provides a structured way for midwives to underpin their offer to women, in order that an increased percentage of women are able to make an informed decision about home birth and/or decide to birth at home. Where midwives apply the AOPHB, women who may take a passive approach could be ‘activated’ to engage in home birth decision making. A pilot intervention has been drafted to implement the AOPHB within clinical practice. The intervention provides support for the implementation of the two-stage AOPHB process through the use of individual components focused on midwives and their employing organisation; student midwives; and women, and their significant others. Implications: This thesis has contributed to the developing knowledge base about planned home birth decision making. The application of active offer theory to the offer of planned home birth has been undertaken for the first time, and this has generated a new and useful perspective on this area of midwifery practice. The resultant two-stage AOPHB process has the potential for developing midwifery practice in terms of supporting midwives to understand and facilitate women’s decision making around home birth, providing a flexible tool that can be used in clinical practice. This is the first approach that has been developed with the aim of increasing the ability of women to make an informed decision about whether they wish to birth at home. Additionally, the pilot AOPHB intervention has implications around the understanding of how employing organisations can best support midwives in this aspect of their role, and developing how student midwives are educated about offering home birth to women.

Solving the cooling flow problem in cool-core galaxy clusters is critical to under- standing the largest structures in the universe. In addition, cool-core systems are the only places where we have observed direct evidence of AGN feedback, and thus provide the unique opportunity to test models of AGN feedback and various other physical processes. In this thesis we study the influence of momentum-driven AGN feedback on cool-core clusters using high-resolution adaptive mesh refinement (AMR) simulations. We find that run-away cooling first happens only in the central 50 pc region while no local instability develops outside the very center of the cluster. The gas is accreted onto the super-massive black hole (SMBH) which powers AGN jets at an increasing rate as the entropy continues to decrease in the core. The ICM first cools into clumps along the propagation direction of the AGN jets due to the non-linear perturbation. As the jet power increases, gas condensation occurs isotropically, forming spatially extended (up to a few tens kpc) structures that resemble the observed Hα filaments in Perseus and many other cool-core cluster. Jet heating elevates the gas entropy and cooling time, halting clump formation. The cold gas that is not accreted onto the SMBH settles into a rotating disk. In the last few Gyr, the ICM cools onto the disk directly while the innermost region of the disk continues to accrete onto the SMBH, powering the AGN jets to achieve a thermal balance. The mass cooling rate averaged over 7 Gyr is &sim 30 solarmass/yr, an order of magnitude lower than the classic cooling flow value (which we obtain in runs without the AGN). Owing to its self-regulating mechanism, AGN feedback can successfully balance cooling with a wide range of model parameters. Besides suppressing cooling, our model produces cold structures in early stages (up to &sim 2 Gyr) that are in good agreement with the observations. However, the long-lived massive cold disk is unrealistic, suggesting that additional physical processes are still needed. Our recent investigation shows that star formation may play an important role.

<div>Detecting hidden/smuggled special nuclear materials (SNM) is one of the unsolved problems in the safeguards industry. The biggest challenge is to quantify and track SNM and prevent the use of these materials for illicit purposes. The goal is to detect smallest quantity of SNM in large cargo containers, at the ports of entry, in the shortest amount of measurement time. Currently passive detection techniques, which is based on long-lived isotopes, are used to detect hidden SNM. This technique is not very reliable, as appropriate shielding of the SNM can reduce detection signals from these long-lived isotopes. Accelerator based active interrogation methods are proposed to solve the SNM problem. Besides SNM, another challenge in the nuclear industry is to meet the demand and supply of medical radioisotopes, particularly Tc-99m (half-life 6 hours). Mo-99, which decays to Tc-99m, is one of the fission products found in nuclear reactors. Because of short half-life of 66 hours, Mo-99 cannot be stockpiled. The shutdown of various research reactors globally disrupted the supply of Mo-99. Because of the financial and regulatory burden on the nuclear reactors, accelerator-based systems can be used to produce Mo-99.</div><div><br></div><div>With the aim to solve these two major challenges, a preliminary study is done to understand the neutrons behavior on milliseconds (or shorter) time steps in an accelerator driven subcritical system. A pulsed external neutron source, i.e. Deuterium-Deuterium (DD) generator, drives the assembly. Using first principles, the transient equations are derived and the neutron population at different time stamps is calculated. The Li-6 detector’s response to the neutron population is predicted. Experiments are performed to compare the predicted behavior with the observed behavior. The model is extended further to investigate the case of no uranium fuel inside the system. Transient measurements, in the absence of the uranium fuel, are made and the neutron die-away time is determined. This die-away time is compared with the predicted time.</div>

A crescente necessidade de produzir circuitos integrados (CIs) cada vez mais miniaturizados para aplicações na faixa de microondas (frequências acima de 1 GHz) com baixo custo de produção e baixo consumo de potênca tem motivado a utilização da tradicional tecnologia Complementary Metal Oxide Semiconductor (CMOS) sobre substrato de silício (Si). Uma aplicação de particular interesse em circuitos integrados operando na faixa de microondas a dos indutores ativos. Rotineiramente, estes indutores ativos são fabricados por meio de processos relativamente custosos como aqueles normalmente envolvidos em tecnologias empregando substrato de arsenato de gálio (GaAs). Por outro lado, novas técnicas de litografia CMOS têm possibilitado a construção de transientes MOSFETs alcançando elevadas frequências de operação. Dessa maneira, o objetivo principal deste trabalho é realizar uma investigação da possibilidade de implementação de indutores ativos operando na faixa de microondas empregando uma tecnologia CMOS convencional sobre substrato de silício. Historicamente, a tecnologia CMOS é atrativa devido às suas características de baixo custo de produção, baixo consumo de potência, alta imunidade aos ruídos e também por oferecer maturidade tecnológica. / The growing need to produce integrated circuits (ICs) increasingly miniaturized for applications in the microwave range (frequencies above 1 GHz) with low cost of production and low consumption power has been stimulating the utilization of traditional technology complementary metal oxide semiconductor (CMOS) on silicon (Si) substrate. One application of particular interest in integrated circuits operating in the microwave range is the active inductors. Ordinarily, these active inductors are fabricated by using relatively expensive technological processes like those usually involved in the gallium arsenide (GaAs) technology. Nonetheless, new techniques of lithography applied to CMOS technology have allowed fabricating MOSFETs transistors reaching high frequencies of operation. In this way, the main goal of this work is realize an investigation of the possibility to implement active inductors operating in the microwave range by using traditional CMOS technology, developed on silicon substrate. Historically, the CMOS technology is attractive by its characteristics of low cost of production, low consumption of power, high immunity to noise and also by offering technological maturity.

Children’s active outdoor play (AOP) is an unstructured physical activity that takes place outdoors during a child’s free time. Despite its association with health and well-being benefits (e.g. increases levels of physical activity, improves psychosocial skills), growing evidence suggests that children are playing less outdoors in comparison to previous generations (Clements, 2004; Witten et al., 2013). This trend is generating a number of studies aiming to examine its decline. Parents, especially mothers, are identified as significant actors in increasing children’s opportunities for AOP in order to prevent adverse health and developmental outcomes. Although parents have an important role in socializing children to leading healthy lifestyles, few studies have documented their difficulties in providing children with opportunities for AOP. Drawing on a Foucauldian approach, this qualitative study focuses on the social, cultural, and structural factors that shape children’s opportunities for AOP within the family context and examines the salient factors of contemporary motherhood that impact children’s AOP. Twenty-one mothers from the Ottawa-Gatineau region took part in an in-depth semistructured interview. The analysis shows that many aspects of contemporary mothering and the multiple roles occupied by mothers make it difficult to provide opportunities for AOP. A key finding is that mothers struggle to prioritize children’s AOP due to discursive conflicts that stem from their roles as risk managers, time managers, and screen time managers. Results provide crucial data for future initiatives aimed at increasing children’s levels of physical activity within a family setting. By focusing on the lived experiences of mothers, this study provides recommendations to promote AOP despite the challenges of contemporary family life.

Made available in DSpace on 2014-06-11T19:22:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-11-29Bitstream added on 2014-06-13T19:27:37Z : No. of bitstreams: 1 souza_be_me_jabo.pdf: 761249 bytes, checksum: d4605eba9bcf738bd4d794a1e0b76819 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / A motilidade espermática é um fator chave para a determinação da qualidade do sêmen e sua capacidade de fertilização. Vários fatores influenciam a motilidade espermática como: espécie estudada, qualidade dos gametas, tipo, volume, temperatura e pH da solução ativadora. Assim sendo, o presente trabalho objetivou avaliar o efeito que a temperatura da solução ativadora e, a relação volume de sêmen:água exercem sob a duração da motilidade espermática. Foram utilizados 12 machos de curimbatá, Prochilodus lineatus com peso e comprimento padrão médio de 405,83 ± 134,20 g, 25,63 ± 3,19cm, respectivamente. Os reprodutores receberam duas doses de extrato de hipófise de carpa (dose inicial de 0,5 mg.kg-1 e final de 5,0 mg.kg-1). Do sêmen dos 12 machos foi realizado um “pool” e, analisada a concentração e o índice de sobrevivência espermática, bem como, a duração da motilidade espermática. Para o primeiro ensaio foi utilizado um delineamento experimental inteiramente casualizado e os tratamentos foram compostos pelos volumes de sêmen provenientes do “pool” e a água nas proporções de: 1:1, 1:2, 1:20, 1:200, 1:2000, 1:20000 e 1:100000SL, respectivamente. O segundo ensaio utilizou um delineamento experimental inteiramente casualizado os tratamentos foram constituídos por alíquotas de 5μL do “pool” de sêmen e, adicionadas a 200μL de solução ativadora nas seguintes temperaturas: 5, 10, 15, 20, 25, 30, 35, 40, 45 e 50°C. A duração da motilidade espermática do curimbatá, P. lineatus teve um comportamento linear ascendente em função do aumento da diluição a partir de 1:2SL sêmen:água (23,04s), até atingir o valor máximo estudado que foi de 1:100.000SL sêmen:água, com a duração da motilidade espermática de 28,83s Os melhores resultados de duração da motilidade espermática em função da temperatura da solução ativadora foram obtidos... / Sperm motility is a key element to qualify semen and its fertilization capacity. Several factors act on sperm motility such as studied species, gametes quality, kind, volume, temperature and pH of activation swimming solution. That way, this study had as a goal evaluate the efect that the temperature of active solution and semen:water volume roll exert on the sperm motility duration. Twelve male curimbatás, Prochilodus lineatus with average weight and medium standard length of 405,83 ± 134,20 g, 25,63 ± 3,19cm, respectively were used. Reproducers got two doses of pituitary extract from carp (initial dose of 0,5 mg.kg-1 and final of 5,0 mg.kg- 1). Whit the semen of those 12 male animals was made a pool and analysed its concentration and spermatic survival index and also sperm motility duration. For the first analysis it was utilized an experimental design entirely randomized and treatments were compound by semen volume deriving from that pool and the water on the proportion of 1:1, 1:2, 1:20, 1:200, 1:2000, 1:20000 e 1:100000SL, respectively. The second analysis utilized an experimental delineation entirely randomized, treatment were composed by 5μL from the pool of the semen and added to a 200μL active solution on the following temperatures: 5, 10, 15, 20, 25, 30, 35, 40, 45 e 50°C. Sperm motility duration of “curimbatá”, P. lineatus had an ascendent linear behavior in function of dilution increasing from 1:2SL semen:water (23,04s), until it gets the maximum studied value that was 1:100.000SL semen:water with the sperm motility duration of 28,83s. Best results of sperm motility duration in function of active solution temperature were gotten in temperature of 20°C wich provided a medium duration of motility of 22,51 ± 0,79 seconds.

Polyglutamine (polyQ) diseases are a group of progressive neurodegenerative disorders, which are caused by the expansion of an existing glutamine-coding CAG repeat in the coding region of disease genes. The cell nucleus is a major site of polyQ toxicity, and gene transcription is compromised in polyQ-induced neurodegeneration. Understanding the nuclear translocation of mutant polyQ proteins is therefore crucial to unfold the complex pathogenic mechanisms that underlie the neuronal toxicity of polyQ disease. The polyQ domain is the only common sequence found among different mutant disease proteins. Nuclear transport signals have been identified in some, but not all, polyQ disease proteins. The detection of those mutant polyQ proteins that carry no classical nuclear transport signal, but not their normal counterparts, in the cell nucleus suggests the existence of uncharacterized nuclear transport signals in mutant polyQ proteins. Thus, the objective of the present study is to elucidate the nuclear transport pathway(s) adopted by an expanded polyQ domain and determine its correlation with polyQ toxicity. / Through a series of genetic and biochemical studies in cell culture, mouse and transgenic Drosophila models, exportin-1 was found to modulate the nucleocytoplasmic localization of mutant polyQ protein and its toxicity. Further, mutant polyQ protein was also demonstrated to be a novel transport substrate of exportin-1. By promoting the nuclear export of mutant polyQ protein, exportin-1 suppressed polyQ toxicity by reducing the interference of mutant polyQ protein on gene transcription. It was found that the protein level of exportin-1 diminished in the normal ageing process, which would result in an exaggeration of nuclear mutant polyQ toxicity. Thus, the age-dependent decline of exportin-1 level, at least in part, accounts for the progressive degeneration observed in polyQ patients. Results obtained from this project first demonstrated that expanded polyQ domain is a nuclear export signal, and further provided mechanistic explanation of how protein nuclear transport receptors modulate polyQ toxicity. / Chan, Wing Man. / Source: Dissertation Abstracts International, Volume: 71-01, Section: B, page: 0113. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 189-203). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese.