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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
741

A PSYCHOSOCIAL MODEL OF DISABILITY IN INTERSTITIAL CYSTITIS / PAINFUL BLADDER SYNDROME

KATZ, LAURA 30 August 2011 (has links)
Interstitial Cystitis / Painful Bladder Syndrome (IC/PBS) is a persistent and refractory medical condition that is characterized by chronic pelvic pain along with abnormal urinary frequency and urgency. There is no widely accepted etiology or efficacious cure for IC/PBS, thus treatment often relies on pain and symptom management. IC/PBS is associated with strong functional disability but theoretical models of disability have yet to be tested with these patients. As well, psychosocial factors associated with various IC/PBS outcomes (i.e., depression, catastrophizing, social support) are also associated with disability in a variety of chronic painful medical conditions but remain untested in disability models for IC/PBS. Thus, this research evaluated psychosocial factors as potential mediators of disability within the Disablement Process Model. Female patients diagnosed with IC/PBS by a urologist in a tertiary care hospitals were recruited (n=196; females). In using structural equation modeling of a final IC/PBS disability model, negative affect and catastrophizing were found to be partial mediators on the relationship between impairments and functional disability and social support was not a significant mediator of disability. Negative affect and catastrophizing may be key psychosocial factors in IC/PBS disability. Research implications for the Disablement Process Model and potential clinical interventions are discussed in light of the current findings. / Thesis (Master, Psychology) -- Queen's University, 2011-08-29 14:18:29.478
742

From Current Collectors to Electrodes : Aluminium Rod Structures for Three-dimensional Li-ion Micro-battery Applications

Oltean, Gabriel January 2014 (has links)
The potential use of 3D aluminium nanorod structures as current collectors and negative electrodes for 3D Li-ion micro-batteries was studied based on the use of relatively simple and cost-effective electrochemical and sol-gel deposition techniques. Aluminium rod structures were synthesised by galvanostatic electrodeposition using commercial porous membranes as templates. It was shown that the use of a short (i.e., 50 ms long) potential pulse (i.e., -0.9 V vs. Al3+/Al) applied prior to a pulsed current electrochemical deposition gave rise to homogeneous deposits with more even rod heights.  Electrophoretic and sol-gel deposition of TiO2 on the same substrates were also studied. The use of the sol-gel technique successfully resulted in a thin coating of amorphous TiO2 on the Al nanorod current collector, but with relatively small discharge capacities due to the amorphous character of the deposits. Electrophoretic deposition was, however, successful only on 2D substrates. Anodisation of titanium was used to prepare 3D TiO2 nanotube electrodes, with a nanotube length of 9 um and wall thickness of 50 nm. The electrodes displayed high and stable discharge capacities of 460 µAh/cm2 at a 0.1 C rate upon prolonged cycling with good rate capability. The 3D aluminium nanorod structures were tested as negative electrodes for Li-ion cells and the observed capacity fading was assigned to trapping of LiAl alloy inside the aluminium electrode caused by the diffusion of lithium into the electrode, rather than to pulverisation of the aluminium rods. The capacity fading effect could, however, be eliminated by decreasing the oxidation potential limit from 3.0 to 1.0 V vs. Li+/Li. A model for the alloying and dealloying of lithium with aluminium was also proposed. Finally, a proof-of-concept for a full 3D Li-ion micro-battery with electrodes of different geometries was demonstrated. The cell comprised a positive electrode, based on LiFePO4 deposited on a carbon foam current collector, with an area gain factor an order of magnitude larger than that for the Al nanorod negative electrode. This concept facilitates the balancing of 3D Li-ion cells as the positive electrode materials generally have significant lower specific energy densities than the negative electrodes.
743

Language ideologies and attitudes of Francophone learners towards English in Yaoundo, Cameroon

Abongdia, Jane-Francis Afungmeyu January 2009 (has links)
<p>English is the most widely spoken language in the world and for this reason it would be of advantage for everyone to learn it. This thesis reports on the language ideologies and attitudes of Francophone learners towards English in the Central Province of Cameroon, a central African country. It offers a critical examination of the different attitudes and motivations of Francophone learners towards English as a third language at secondary schools in the city of Yaound&eacute / . It also presents the most important factors that appear to play a role in shaping their attitudes towards English, a language that many of the respondents appear to find hard to learn. Central to these factors are the prevailing language ideologies in Cameroon.</p>
744

Spherical harmonic inductive detection coils and their use in dynamic pre-emphasis for magnetic resonance imaging

Edler, Karl 13 September 2010 (has links)
The issue of eddy currents induced by the rapid switching of magnetic field gradients is a long-standing problem in magnetic resonance imaging. A new method for dealing with this problem is presented whereby spatial harmonic components of the magnetic field are continuously sensed, through their temporal rates of change, and corrected. In this way, the effects of the eddy currents on multiple spatial harmonic components of the magnetic field can be detected and corrections applied during the rise time of the gradients. Sensing the temporal changes in each spatial harmonic is made possible with specially designed detection coils. However to make the design of these coils possible, general relationships between the spatial harmonics of the field, scalar potential, and vector potential are found within the quasi-static approximation. These relationships allow the vector potential to be found from the field – an inverse curl operation – and may be of use beyond the specific problem of detection coil design. Using the detection coils as sensors, methods are developed for designing a negative feedback system to control the eddy current effects and optimizing that system with respect to image noise and distortion. The design methods are successfully tested in a series of proof-of-principle experiments which lead to a discussion of how to incorporate similar designs into an operational MRI.
745

Maternal Responses to Anticipated Children's Negative Emotions and Social Adjustment in Early Childhood

Lundell, Leah J. 26 February 2009 (has links)
The goals of the present study were: 1) to describe and provide initial support for the validity of the Future Scenarios Questionnaire (FSQ), a new self-report questionnaire designed to measure parental responding to anticipated children’s negative emotions; and 2) to examine how maternal responses on the FSQ related to young children’s aggressive, asocial, and prosocial behaviors with peers. Further, this study examined whether the temperamental trait of negative affect moderated the relation between maternal responses on the FSQ and children’s social adjustment outcomes. Participants were 92 mothers of preschool-age children (43 boys and 49 girls; M age 61.5 months). Mothers provided ratings on the FSQ and child temperament ratings on the Child Behavior Questionnaire (CBQ; Rothbart, Ahadi, & Hershey, 1994). They also completed a range of measures which were included to assess the construct validity of the FSQ. These included measures of attachment representations, maternal mind-mindedness, perceived control, and alexithymia. Sixty-nine teachers provided ratings on the Child Behavior Scale (CBS; Ladd & Profilet, 1996) for children’s aggressive, asocial, and prosocial behaviors in the peer context. Factor analysis of the FSQ revealed two subscales: Encourage Emotion Expression (EEE) and Discourage Emotion Expression (DEE). Patterns of correlations among these subscales and the additional mother measures suggested that the FSQ demonstrates some construct validity. Further, the results of the moderation analyses showed that maternal responding on the FSQ interacts with negative affect in the prediction of child behaviors, however not in the hypothesized ways. In particular, encouraging emotion expression significantly predicted more asocial behavior and less prosocial behavior (approached significance), but only for children rated high in negative affect. Similarly, discouraging emotion expression significantly predicted less aggressive behavior only for high negative affect children. None of these relations was significant for children rated low in negative affect. The theoretical and practical implications of these findings are discussed in terms of the importance of considering child temperament in emotion socialization processes.
746

Children’s Moral Emotions and Negative Emotionality: Predictors of Early-onset Antisocial Behaviour

Colasante, Tyler 21 November 2013 (has links)
This study examined links between antisocial behaviour, moral emotions (i.e., sympathy and guilt), and negative emotionality in an ethnically diverse sample of 4- and 8-year-old children (N = 79). Primary caregivers reported their children’s antisocial behaviour, sympathy, and negative emotionality through a questionnaire and across a 10-day span via daily diary entries (n = 474 records). In a semi-structured interview, children reported their sympathy levels and guilt feelings. Children with high guilt in harm contexts and low negative emotionality were rated as less antisocial in both questionnaire and diary reports. For children with low guilt in exclusion contexts, low sympathy ratings predicted higher questionnaire-reported antisocial behaviour. For children with high guilt in prosocial omission contexts, high sympathy ratings predicted lower diary-reported antisocial behaviour. Lastly, high sympathy ratings predicted lower questionnaire-reported antisocial behaviour for children with low negative emotionality.
747

Reinforcement learning for qualitative group behaviours applied to non-player computer game characters

Bradley, Jay January 2010 (has links)
This thesis investigates how to train the increasingly large cast of characters in modern commercial computer games. Modern computer games can contain hundreds or sometimes thousands of non-player characters that each should act coherently in complex dynamic worlds, and engage appropriately with other non-player characters and human players. Too often, it is obvious that computer controlled characters are brainless zombies portraying the same repetitive hand-coded behaviour. Commercial computer games would seem a natural domain for reinforcement learning and, as the trend for selling games based on better graphics is peaking with the saturation of game shelves with excellent graphics, it seems that better artificial intelligence is the next big thing. The main contribution of this thesis is a novel style of utility function, group utility functions, for reinforcement learning that could provide automated behaviour specification for large numbers of computer game characters. Group utility functions allow arbitrary functions of the characters’ performance to represent relationships between characters and groups of characters. These qualitative relationships are learned alongside the main quantitative goal of the characters. Group utility functions can be considered a multi-agent extension of the existing programming by reward method and, an extension of the team utility function to be more generic by replacing the sum function with potentially any other function. Hierarchical group utility functions, which are group utility functions arranged in a tree structure, allow character group relationships to be learned. For illustration, the empirical work shown uses the negative standard deviation function to create balanced (or equal performance) behaviours. This balanced behaviour can be learned between characters, groups and also, between groups and single characters. Empirical experiments show that a balancing group utility function can be used to engender an equal performance between characters, groups, and groups and single characters. It is shown that it is possible to trade some amount of quantitatively measured performance for some qualitative behaviour using group utility functions. Further experiments show how the results degrade as expected when the number of characters and groups is increased. Further experimentation shows that using function approximation to approximate the learners’ value functions is one possible way to overcome the issues of scale. All the experiments are undertaken in a commercially available computer game engine. In summary, this thesis contributes a novel type of utility function potentially suitable for training many computer game characters and, empirical work on reinforcement learning used in a modern computer game engine.
748

Hormone replacement therapy and effects on mood

Björn, Inger January 2003 (has links)
Background: During the past 5 decades, hormone replacement therapy (HRT) has been used, and appreciated for its beneficial effects, by millions of women in their menopause. As treatment for climacteric symptoms, estrogen is outstanding, and effects on hot flushes, vaginal dryness, and insomnia have been widely documented. The increased risks of venous thrombosis and breast cancer, however, restrict the use of estrogen. Estrogen treatment in women with a remaining uterus includes a progestin, added to protect the endometrium from hyperplasia and malignancies. The long-standing clinical impression, that progestin addition negatively influences mood, has been discussed in previous studies. Mood deterioration is, however, not mortal, although mood is important to the wellbeing and daily functioning of women treated with hormones. Studies of the mental side effects of HRT add to our understanding of steroid effects in the brain. Aims and methods: In our studies, we aimed to establish to what extent negative side effects cause women to discontinue HRT, and find out which drug compounds lead to mood deterioration. The questions asked were whether the type and dose of progestin and the estrogen dose during the progestin addition influence the mood and physical symptoms during sequential HRT. Compliance with HRT and reasons for discontinuing the therapy were evaluated in a retrospective longitudinal follow-up study. Treatment effects were studied in three randomized, double-blind, cross-over trials. During continuous estrogen treatment, effects of sequential addition of a progestin were studied by comparing two different progestins, medroxyprogesterone acetate (MPA) andnorethisterone acetate (NETA), comparing different doses of the same progestin, MPA, and comparing two doses of estrogen during addition of the same dose of MPA. The main outcome measure was the daily rating on mood and physical symptoms kept by the participants throughout the studies. The clinical trials were carried out at three gynecological centers in northern Sweden. Results and conclusions: Besides fear of cancer and a wish to determine whether climacteric symptoms had meanwhile disappeared, negative side effects was the most common reason or discontinuing HRT. Tension in the breasts, weight gain, a depressed mood, abdominal bloating, and irritability were the most important side effects seen both in women who continued HRT and in women who had discontinued the therapy. In our clinical trials, we showed that addition of a progestin to estrogen treatment induces cyclic mood swings characterized by tension, irritability, and depression, as well as increased breast tension, bloatedness, and hot flushes. Women with a history of premenstrual syndrome (PMS) appeared to be more sensitive to the progestin addition and responded with lower mood scores compared with women without previous PMS. In our studies, MPA provoked depressed mood to a lesser extent than did NETA. Surprisingly, the higher dose of MPA (20 mg) enhanced the mood, compared with 10 mg, when added to estrogen treatment. In women continuously treated with 3 mg estradiol, mood and physical symptoms worsened during the progestin addition, as compared with treatment with 2 mg estradiol. The negative side effects seen during sequential HRT have much in common with symptoms seen in the premenstrual dysphoric disorder (PMDD), which is a psychoneuroendocrine disorder with psychiatric expression. Explanations for treatment effects on mood are likely to be found in drug interactions with neurotransmitter systems of the brain. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 2003</p> / digitalisering@umu
749

Chromosomal β-lactamases in enterobacteria and in vivo evolution of β-lactam resistance

Bergström, Sven January 1983 (has links)
The ß-lactam antibiotics are the most important antibacterial agents in the treatment of infectious diseases. A severe problem in ß-lactam therapy is the emergence of ß-lactam resistant bacteria. Clinical ß-lactam resistance is most often due to the production of ß-lactamases. ß-lactamase genes reside either on plasmids or on the chromosome. The aim of this study was to acquire an understanding of organisation and regulation of chromosomal ß- lactamase genes in different Gram negative species and to elucidate the mechanisms for ampC hyperproduction in the in vivo situation. By DNA hybridization with an ampC probe from Escherichia coli K-12 it was shown that other Gram negative bacteria contained an artpC like chromosomal gene, suggesting a common evolutionary origin. Furthermore, the preceding frd operon that overlaps the ampC gene in E. coli K-12 was found to be much more conserved than the ampC gene in the bacterial species investigated. The ampC and frd opérons in Shigella sonnei and Citrobacter freundii were cloned and characterized by physical mapping. The respective maps were compared to the ampC and frd region in E. coli K-12. The physical map of Sh. sonnei was almost identical to the E. coli K-12 map, whereas in C. freundii only the frd region exhibited any considerable homology. Moreover, in C. freundii, the anpC and frd regions were separated by 1100 basepairs. It is suggested that this DNA is involved in the induction of ß-lactamase production in this organism. A hypothesis for the evolution of the anpC operon in enterobacteria is presented. By isolating and characterizing six ß-lactam resistant clinica], isolates of E. coli hyperproducing the dhrcmosomal ß-lactamase, genetic mechanisms for in vivo evolved resistance was aimed at. These isolates exhibited a 24-48 fold increase in ß-lactamase production. The ß-lactamase produced was found to be biochemically and immunologically identical to the ß-lactamase produced by E. coli K-12. The ampC control region of these six E. coli isolates was DNA-seqenced. The cause of ß-lactamase hyperproduction in five of the clinical E. coli isolates, identical in the DNA segment sequenced, was due to a strong novel ampC promoter displaced 5 bp upstream of the ampC promoter defined in E. coli K-12. The ß-lactamase hyperproduction in the sixth clinical isolate was shown to be caused by two mutations affecting both the promoter and the attenuator in the regulatory region defined by E. coli K- 12. The obtained changes were sufficient to explain the increase in ampC ß- 1 act ama se expression exhibited in these clinical E. coli isolates. Sequence analysis of the ampC control region in Sh. sonnei revealed that it was, with one exception, identical to the one found in the five clinical E. coli ß-lactamase hyperproducers. The only difference was in a position that creates the strong novel ampC promoter in the E. coli hyperproducers. By isolating spontaneous Sh. sonnei mutants with a 40-fold increase in ß-lactamase production carrying the same novel ampC promoter as the clinical E. coli isolates it was concluded that this DNA segment has been transferred in vivo frcm Shigella to E. coli across the species barrier. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1983; Härtill 5 uppsatser</p> / digitalisering@umu
750

COGNITIVE THERAPY FOR THE TREATMENT OF DEPRESSIVE SYMPTOMS IN PATIENTS WITH HEART FAILURE

Dekker, Rebecca L. 01 January 2010 (has links)
Depressive symptoms are common in patients with heart failure (HF) and adversely affect mortality, morbidity, and health-related quality of life. Cognitive therapy (CT) has been proposed as a non-pharmacological treatment for depressive symptoms in patients with HF. However, there is currently little evidence to support use of CT in patients with HF. The purpose of this dissertation was to develop and test a brief, nurse-delivered CT intervention for the treatment of depressive symptoms in patients with HF. Prior to testing the intervention, preliminary work was conducted resulting in four manuscripts: 1) a review of the evidence for CT in treating depressive symptoms in patients with cardiovascular conditions, 2) a description of living with depressive symptoms in patients with HF and strategies that could be used to manage these symptoms, 3) a review of measures of negative thinking and the identification of a measure of negative thinking that can be used in patients with HF, and 4) an evaluation of the psychometric properties of this measure. Based on information from these manuscripts, a randomized, controlled pilot study was conducted to test the effects of a brief CT intervention on outcomes of hospitalized patients with HF who report depressive symptoms. Forty-two hospitalized patients with HF with mild-moderate depressive symptoms were randomized to a brief CT intervention focused on reducing negative thoughts with thought-stopping and affirmations, or to usual care control. Both groups experienced improvements in depressive symptoms, health-related quality of life, and negative thinking at one week and three months. However, the intervention group experienced longer cardiac event-free survival and fewer cardiovascular hospitalizations and emergency department visits at three months when compared to the control group. This dissertation has fulfilled an important gap in the evidence base for depression treatment in patients with HF by demonstrating that a nurse-delivered, brief CT intervention may improve cardiac event-free survival in patients with HF. This brief CT intervention is replicable, practical, can be delivered by acute care nurses, and may improve clinical outcomes in patients with HF. Additional research is needed to determine the effects of the intervention on long-term outcomes in patients with HF.

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