VictorJuiz/thesis huggingface dataset:
A randomized controlled trial of the effects of the bath in labour

Taking a bath in labour has become increasingly popular, however, the scientific evidence regarding effectiveness has been inconclusive. The purpose of this study was to determine whether a policy to encourage a bath reduced the use of epidural analgesia. Other effects were also evaluated: labour and birth events, fetal/newborn. health, women's perceptions of their childbirth experience and, in the experimental group, pain measures pre mid post bath immersion. The Gate Control Theory was used to explain the potential benefits of the bath. In this two-site study, 635 healthy, labouring, women were randomly allocated, with stratification for parity and site, to an experimental group (n = 319) for whom baths were encouraged, and a control group (n = 316) who received conventional care. An intent-to-treat method of analysis was used and a crossover rate of 18% resulted for each group. There were no differences between groups in the use of epidural analgesia (experimental group, 245/319, 76.8%; control group, 240/316, 75.9%, 1p = .90) and labour and birth events, with the exception that the control group was more likely to experience meconium stained amniotic fluid during labour (62/316, 19.7%, vs. 43/319, 13.6%, 2p = .04). Newborn outcomes between the groups were not significantly different. Mean scores for pain intensity and affect were significantly lower with bath immersion (intensity: pre, 6.39 ± 1.93; post, 5.59 ± 2.19, 2p = < 0.0005; affect: pre .760, ± .141; post, .682, ± .202, 2p = <0.0005). The mean scores for women's retrospective rating of overall labour pain intensity and affect were higher for the experimental group (intensity: 7.72 ± 1.7 vs. 7.37 ± 2.1, 2p = .049; affect: .795 ± .118 vs. .756 ± .184, 2p = .005). The experimental group had higher mean scores on a scale that measured the frequency of selected, supportive, nursing activities (45.04 ± 7.6 vs. 43.20 ± 7.3, 2p = .005). The most prevalent themes about bathing, from the content analysis of the women's comments, were relaxation and pain relief. Further study should be undertaken to measure the effect of the bath on relaxation and anxiety, given the women's written comments.
Validating conditioned antisickness theory, the explanation for the aversion failure phenomenon and the basis of a clinical nondrug conditioning strategy for the alleviation of nausea and emesis

Many species learn an aversion to a novel taste if made sick within hours of consumption. Most drugs induce such conditioned taste aversions (CTAs) and are therefore supposed to produce nausea or sickness, but such drugs are variably effective at optimal doses. By traditional Pavlovian conditioning principles, it should be possible in theory to increase the effectiveness of a drug that induces a mild CTA by first pairing it with a more effective drug tied induces a strong CTA. In Pavlovian terminology, if a conditioned stimulus (CS) drug such as pentobarbital--known to induce weak CTAs--is paired with an unconditioned stimulus (US) drug such as lithium--known to induce strong CTAs--on several occasions, the CS drug should come to induce stronger CTAs in a subsequent procedure than would otherwise be expected. One possible account of this aversion failure (avfail) phenomenon hinges on selective association of an internal drug state CS with a hypothetical homeostatic or ' antisickness' aftereffect of sickness. According to conditioned antisickness (CAS) theory, drug states model naturally occurring sequences of internal states. The CS drug corresponds to naturally occurring internal signals, the US drug to naturally occurring aftereffects, and conditioning enables the animal to better regulate its internal environment by anticipating the US. Drug-drug conditioning provides a general model for the involvement of Pavlovian conditioning in homeostatic regulation. The drug-drug pairings methodology has made CAS theory difficult to valid because nonindependence of the two drug states invites a pharmacological drug interaction alternative to a conditioning interpretation. The joint presence of particular CS and US drugs in the experimental group but not in Pavlovian controls could produce unique pharmacological effects that somehow mimic avfail. In an indirect test of CAS theory, Lett (1992) paired drug or place cues with lithium and found that rats with an experimental or forward pairings history ate less food on test, consistent with a traditional conditioned sickness account rather than with CAS. But rats eat dirt or clay in response to sickness and adaptively eat small amounts of food when clay is not available: Paradoxically, perhaps rats with a forward pairings history ate less food than controls because they were less rather than more sick. (Abstract shortened by UMI.)
Cultural discourse on the Muslim woman in African francophone literature

In this study, we undertake a socio-cultural analysis of female existence in narrative spaces produced by African francophone writers of Muslim cultural background. We begin this analysis with the premise that one of the fundamental components of any culture is a set of values rooted in religious doctrine. Since the literary text is also a component of that same culture, we can state that texts produced in a Muslim cultural context are implicitly influenced by Islamic doctrine and traditions. In this intertextual study, an examination of the construction of space as well as spatio-temporal relationships in an Islamic society is followed by an analysis of the organization of gendered spaces along with that of female existence in narrative discourses by both male and female African Muslim writers. One of the principal goals of this study is to describe precisely the role of Islamic socio-cultural norms in the creation of the Muslim female in the literary text. The social realist treatment of the female character by African Muslim writers is not a simple mimetic production of a literary Islamic universe in which the female character is objectified and silenced by patriarchal practices. While maintaining a specific cultural context, the literary text also functions as an initiator of change, announcing a rupture with social realities as well as a social re-definition of the female character.
Subadult growth and health from ossuary samples of prehistoric Southern Ontario Iroquoian populations

A growth deficit in juveniles, specifically toddlers, has been demonstrated for many prehistoric and historic skeletal samples in North America. All of these samples consist of skeletons with matching dentitions and long bones. This thesis explores the possibility of detecting a growth deficit in four ossuary samples from Southern Ontario where long bones and dentitions are no longer in association. Each of the four ossuary samples (Fairty, Kleinburg, Carton and Milton) were extensively researched, with regards to their excavation and post-excavation histories, in an attempt to control environmental bias. In one case, radiocarbon dating was done to clarify the date of a sample (Fairty). The results indicate a date much earlier than previously thought, although this date cannot be easily accepted. Potential cultural bias of the samples was addressed by a thorough review of the ethnohistoric documents, and critical appraisal of the demographics of the samples themselves. Much of the research presented here was done in order to minimize potential methodological bias, which has been cited as the most frequent cause of a perceived growth deficit in skeletal samples. Fairty, a pre-contact, marginal horticultural sample displayed a juvenile growth deficit which was most pronounced in the 1 to 3 year age groups. Kleinburg, a circa-contact maize horticultural. sample did not display a longitudinal bone growth deficit in the juveniles, but a cortical bone deficit in both the juveniles and adults of this sample has been shown by the work of others (Saunders and Melbye 1990). The Carton and Milton ossuary samples were biased by human-induced taphonomic changes so severely that no information on growth deficit in juveniles could be derived from them. The concluding chapter of this thesis provides alternative interpretations of subadult health in Southern Ontario by utilizing the results of this, and previous studies on the same samples. These interpretations am based upon the assumptions that high frequencies of stress related skeletal changes can either be pathological, and therefore indicative of excessive morbidity, or they can be viewed as adaptive, and therefore would not have caused any overt clinical illness. These results are considered to be sample specific.
Mechanisms of free radical formation and toxicity in an in vitro model of ischemia

In light of recent observations suggesting that free radical (FR) formation is an obligatory step of excitotoxic neuronal death, the knowledge of the molecular mechanisms by which FRs are produced and induce cell damage is very important. Results of this study suggest that ischemic FR generation occurs due to glutamate-mediated intracellular calcium rises primarily in mitochondria, and depends on mitochondrial calcium uptake and pyridine nucleotide hydrolysis. Also presented is the first direct evidence of ischemia-induced prolonged, Cyclosporin A-sensitive loss of mitochondrial potential, indicative of a specific mitochondrial dysfunction, termed the mitochondrial permeability transition (MPT). Isolation and identification of mitochondrial proteins on Cyclosporin A affinity column suggest that MPT might be accomplished by the assembly of a mitochondrial pore-forming protein, porin, cyclophilins, and possibly other proteins, into a mitochondrial megachannel. In addition, reactive oxygen species and mitochondrial dysfunction are found to play a major role in ischemic neurodegeneration, as indicated by the high neuroprotective efficacy of agents preventing FR formation and mitochondrial dysfunction, and free radical scavengers. In summary, these data suggest that mitochondria are the principal source and the primary target of ischemic oxidative stress, and therefore are a major determinant of the cellular fate. (Abstract shortened by UMI.)
A study of the interactions of gas phase molecular iodine with stainless steel tubing

The interactions of I2(g) during flow through type 316 stainless steel tubing was investigated using radiochemical techniques. The purpose was to determine the mechanisms behind I2 losses within sampling lines (PARMS) at Ontario's CANDU nuclear stations. The parameters studied were flow rate, gas phase concentration, relative humidity, and tube surface temperature. Humidity of the air had a significant impact, with low humidities producing surface loading orders of magnitude lower than high humidities. Steady state was achieved using high I2(g) concentrations, whereas with low concentrations, deposition continued throughout the experiments. Maximum loading was observed at 40°C with relative humidities greater than 50%, conditions which may occur when the PARMS would be used. Deposition velocities ranged from 2 cm/sec at the above conditions to 0.0004 or lower at temperatures of 90°C. It was speculated that deposition involved adsorption in localized sites which retained water, resulting in corrosion through a pitting mechanism.
Real indians and others, mixed-race urban native people, the Indian Act, and the rebuilding of indigenous nations

Native identity, for urban mixed-race Native people, is shaped on the one hand by colonial regulation under the 'Indian Act', and on the other by Native heritage and connections to the land. This research engages with how the identities of the participants of this study (as well as the author herself) have been defined and molded by their families' lived experiences of cultural genocide, how the participants have, in resistance, actively explored their Native heritage, and how hegemonic images and definitions of Indianness have influenced these processes. The research is based on interviews with thirty individuals of mixed Native and non-Native heritage living in the Toronto region, on the subject of urban Native identity. The first part of the thesis engages with the methodological concerns which must be taken into consideration when Native peoples' identities are the subjects of academic investigation, the highly distinct circumstances which are raised by the regulation of Native identity in Canada under the ' Indian Act', and the images of Indianness which exist within the dominant culture, which every urban mixed-race Native person must contend with in forming their own identity as a Native person. The second part of the thesis engages directly with the participants' family histories, their opinions about Native identity, and the roles which they are playing in creating and maintaining an urban Native community. The common thread running through the narratives is the devastating affect which loss of community as a result of genocidal government policies has had on the participants' families. The research clearly demonstrates the extent to which government regulation of Native identity, through racist and sexist restrictions within the 'Indian Act', has contributed to the alienation of individuals from their communities and has fragmented Native peoples' identities, dividing them into categories such as "status Indians", "Metis", "Bill C-31 Indians", "reserve Indians" and "urban Indians". In a preliminary manner, it explores the forms of nation-building which might enable Native people to overcome the divisive effects of a history of government regulation of identity.
Navigation-guidance-based robot trajectory planning for interception of moving objects

Motivated by current trends in automation of industrial applications, the general problem area addressed in this thesis is "on-line robot-motion planning for intercepting randomly moving objects." The specific objective of the thesis is "the use of navigation-guidance techniques in the development of a generalized scheme that can intercept a randomly moving object with time-optimality". Two novel methods are presented for on-line-robotic-interception of fast-maneuvering objects which do not require a priori information on the moving-object's motion. Both techniques combine a navigation-guidance-based method with a conventional object-tracking technique. Thus, they are classified as 'hybrid' interception schemes with two phases: Phase I during which the robot is under the control of a navigation-guidance-based technique, and Phase II during which the robot's control is switched to a conventional tracking method. For the first proposed method, an Ideal Proportional Navigation Guidance (IPNG) technique is used during Phase I. This technique moves the interceptor rapidly toward the rendezvous point. For the second proposed method, the augmented form of the IPNG technique is suggested for Phase I, when a reliable estimation of the target's acceleration can be provided to the interceptor. Both techniques are modified in this thesis to reflect the greater mobility of a robotic manipulator over an airborne missile for robotic interception of fast-maneuvering targets. Since IPNG techniques have been originally designed for missile guidance, they do not attempt to match the target's velocity at the interception point. In this thesis, for smooth interception, a tracking method is proposed to be switched on to at an optimal time in order to bring the robot to the interception point matching both target's position and velocity. On-line selection of this time-optimal switching point is discussed in the dissertation. The convergence of the proposed interception methods under ideal conditions is addressed. The effect of noise in target's position readings on the on-line estimation of the interception time, and, subsequently, on the overall performance of the proposed technique is also discussed. Extensive computer simulations illustrate the effectiveness of the IPNG-based interception methods developed in this thesis over pure tracking-based techniques proposed in the cited literature.
Motivational, performance and affective consequences of mastery and performance achievement goals

The present study examined the nature and consequences of the three achievement goals depicted in Elliot's tripartite model (Elliot, 1997; Elliot & Harackiewicz, 1996). 145 college students were randomly assigned a performance-approach, performance-avoidance or a mastery goal, regarding a social perception task. Following the task, participants received positive or negative performance feedback. In accordance with predictions, the mastery goal led to more beneficial outcomes than either performance goal, in both feedback conditions. Compared to both performance groups, mastery participants felt less externally controlled as they awaited the task, reported higher enjoyment and interest in the task, and had more optimistic predictions regarding future performance. The two performance goals had mostly similar outcomes, although a few interesting differences were also observed. Higgins's (1996) regulatory focus theory was also examined in this context, but was not supported. Theoretical implications for the tripartite model of goal framing and future research directions are discussed.
Information overload in computer-mediated communication and education: Is there really too much information? Implications for distance education

The development of computer technology and the rapid growth of the Internet have led to a plethora of on-line information resources. For some domains it seems obvious that information overload is an inevitable result of technological advancements and a subsequent characteristic of the current information revolution. However, it is not clear that this is the case for computer-mediated communication (CMC) in education. Twenty-five adult students in a CMC course with supplemental face-to-face meetings, were observed and measures of the amount of information presented in both media were obtained. In spite of the students' perceptions, it was discovered that the CMC component contained less information than the face-to-face component. Variables that confound students' perceptions are discussed and it is hypothesized that students in CMC courses experience 'stimulus' overload and not 'information' overload per se.
Learning, knowledge building, and subject matter knowledge in school science

Following a theoretical analysis of constructivist approaches to collaborative learning, a curriculum development model, the 'Learning to Knowledge Building Model', is proposed. Two empirical studies of student work with Computer Supported Intentional Learning Environment (CSILE) are then presented; these lend support to the model and explicate in detail the nature and extent of the knowledge developed by elementary school students. The first study is a content analysis of a database developed by a combined Grade 5/6 class as part of a unit on heat and matter, conducted after the children completed their work; the analysis assumes the point of view of a subject matter specialist in the field of the students' inquiry. The second study was conducted while the students' investigation was in progress, and takes the point of view of curriculum coverage; it involved a teacher who used a different model of database use, as well as different subject matter. The proposed LKB model is based on a distinction Bereiter and Scardamalia (1996a) have made between ' learning' and 'knowledge building' (i.e., progressive collaborative problem solving); its aim is to support the design and planning of curriculum units and classroom practices in which knowledge building is central. An important feature of the model is the attention given to ensuring that students learn to evaluate their knowledge and to ask the questions that can advance shared knowledge. Among the findings of the first study are: (a) students who wrote more notes that explicated their commonsense knowledge early in the unit, by means of 'mixed framework' notes, tended to write more notes of high scientific merit later; (b) some of the students in this category tried out their ideas in diverse problem contexts; and (c) they tended to dominate the discussions they started. The second study provides additional insight into the role of the teacher, and the potential role of subject matter specialists, in knowledge building; it also provides a complex picture of the class's performance and the extent to which the various probes used revealed different aspects of this complexity.
Signalling through the T cell costimulatory receptor CD28

T cells are important regulators of the adaptive immune response. T cells become activated when they interact with specialised antigen presenting cells that express processed peptides from pathogens. CD28 is a costimulatory cell surface receptor expressed by T cells. In concert with the T cell receptor for antigen (TcR), CD28 generates signals that promote cytokine production and cell proliferation. T cells that recognise antigens on self tissues that do not express the CD28-ligands, B7-1 or B7-2, enter a non-responsive state, termed anergy, or may undergo programmed cell death. As such, CD28 plays a critical role maintaining immunological tolerance against self-antigens, while promoting immune responses against invading organisms. I have investigated how CD28 transmits signals inside T cells. One consequence of the interaction between B7 and CD28 is that the cytoplasmic domain of CD28 becomes phosphorylated on a tyrosine residue that serves as a docking site for the SH2 domains of phosphoinositide 3-kinase (PI3K) and Grb2. A number of studies have suggested that it is through these interactions that CD28 provides costimulatory signals. I have used a genetic approach to identify the role of this SH2-binding site for costimulation 'in vivo', and found it not to be essential for costimulation of proliferative responses and IL-2 production. Therefore, CD28 must use other protein-interaction sites to recruit intracellular signalling proteins. I have characterised two proline-rich regions in CD28 that bind SH3 domains. One of these regions binds the SH3 domains of Grb2. The recruitment of Grb2 to CD28 through the SH3 domains leaves the Grb2 SH2 domain free to bind signalling proteins that are phosphorylated on tyrosine. This allows CD28 to connect with other signalling molecules, such as Shc, that are involved in T cell activation. The other proline-rich region of CD28 binds the SH3 domain of the tyrosine kinase Itk. CD28 thus brings Itk in proximity with potential proteins involved in CD28 costimulation. The binding of the cytoplasmic domain of CD28 to the SH3 domain of Itk increases the tyrosine kinase activity of Itk.