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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.
621

Mechanisms of brightness perception

Robinson, Alan Edward. January 2009 (has links)
Thesis (Ph. D.)--University of California, San Diego, 2009. / Title from first page of PDF file (viewed Oct. 7, 2009). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 57-58).
622

The role of stimulus matching in the development of intersensory perception in bobwhite quail /

McBride, Thomas, January 1994 (has links)
Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 65-71). Also available via the Internet.
623

Estudo das medidas terapeuticas para reducao da contaminacao interna por radionuclideos

DUARTE, CELINA L. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:36:57Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:25Z (GMT). No. of bitstreams: 1 04450.pdf: 6009089 bytes, checksum: 03cdf0d32f27be5d40a52b81da343b93 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
624

'He's got a life sentence,but I have a life sentence to cope with as well' : the experiences of long-term prisoners' partners

Kotova, Anna January 2016 (has links)
There is a small, but growing, body of research on prisoners' families. It has shown that these families experience numerous pains and deprivations associated with imprisonment, ranging from financial hardship to social (stigma) and emotional issues (grief-like emotions). It has also been suggested that long sentences could exacerbate and prolong these problems. However, no studies on long-term prisoners' families specifically have yet been conducted in the UK. This study explores the experiences of 33 long-term prisoners' partners. Prison sociology, which has explored imprisonment, and long-term imprisonment specifically, is used to inform the analysis. Themes such as coping with the pains of imprisonment over time and with the length of the sentence and time passing are explored. It is also shown that partners are fundamentally changed, on an identity level, by a long sentence. Furthermore, stigma is explored, and it is argued that partners of long-term prisoners experience especially strong stigma and that it lasts for a long time indeed. Finally, this thesis considers how the partners outside 'do family' across prison walls, and how imprisonment makes this challenging indeed. In conclusion, it is argued that the experiences of prisoners' partners speak to the sociological research on imprisonment more broadly and that drawing on these experiences can develop the prison sociologist's knowledge about the broader sociological impact of imprisonment.
625

Amelioration and assessment of gastrointestinal acute toxicity and late effects of pelvic radiotherapy

White, Katherine January 2016 (has links)
Background: Growing numbers of patients with cancer are surviving following treatment with pelvic radiotherapy. Eighty per cent will experience acute gastrointestinal (GI) toxicity during treatment and 50% will subsequently have a change in their bowel habit which will affect their quality of life. The main project in this thesis aims to determine whether delivery of a gastrointestinal bundle of care will decrease GI acute toxicity and late effects of pelvic chemoradiotherapy. Additional work in the thesis evaluated the newer technique of Volumetric Modulated Arc Therapy (VMAT) which delivers decreased dose to the organs at risk on planning scans. We aimed to determine outcomes of this technique in terms of patient-reported acute toxicity and late effects. There is no internationally accepted patient reported outcome measure to capture this toxicity data and this issue was addressed using Rasch analysis in a third project. Methods: A randomised controlled trial was performed. Patients who were scheduled to undergo potentially curative chemoradiotherapy for cervix and bladder cancers were recruited and randomised. The treatment group received dietetic input and if they developed lower GI symptoms they underwent investigations and treatment for bile acid malabsorption, small bowel bacterial overgrowth and lactose intolerance. The control group received standard care. Patients who were to undergo VMAT to treat gynaecological malignancy completed patient-reported outcomes at baseline, end of treatment and one year. The rates of patient-reported toxicity were compared with those of a historical cohort and were correlated with the volume of small bowel which was irradiated. Thirdly the technique of Rasch analysis was used to evaluate the Common Terminology Criteria for Adverse Events derived patient reported outcome to measure pelvic toxicity of gynaecological cancer treatments. Results: It was feasible and acceptable to deliver a GI care bundle to patients undergoing chemotherapy and pelvic radiotherapy. All patients' data were available for analysis for the primary outcome and 29 patients' data were available at the 1 year time point. GI toxicity at 6 weeks was predicted by the trial group, suggesting that the intervention benefited the patients in terms of GI toxicity at 6 weeks. It is not yet clear whether this benefit is maintained at the 1 year time point. The frequencies of acute and late GI toxicity reported by patients undergoing VMAT were similar to that of a historical cohort who received conformal therapy. There was not a strong association between the volume of small bowel which was irradiated and the toxicity which was reported suggesting that other factors are involved in the development of toxicity. Rasch analysis of the pelvic symptom questionnaire demonstrated the main issue to be response dependency. When this was accounted for by grouping items into sub-tests the questionnaire could be made to be unidimensional and showed high reliability in a symptomatic population. Conclusion: GI intervention holds promise as a measure to reduce the acute toxicity and late effects of pelvic radiotherapy. Although newer radiotherapy techniques appear to decrease the dose delivered to the small bowel this does not translate to a reduction in patient-reported toxicity. The measurement of toxicity is complex and patient-reported outcome measures should be developed with techniques such as Rasch analysis to ensure meaningful data is available to guide further developments to reduce GI toxicity secondary to pelvic radiotherapy.
626

Ontogenesis of central opioid systems in rats perinatally exposed to lead

McDowell, Julia January 1988 (has links)
The literature relating to the ontogeny of the opioid system and to the toxic effects of lead in both man and animals with particular reference to neurochemical and behavioural toxicity of lead is reviewed. The effects of perinatal lead exposure on the development of several aspects of opioid function has been studied using a dosing model of lead (as the acetate) in the maternal drinking water from conception until postnatal day 14 or 21. This model of low level perinatal lead exposure in rats had no toxic effects on growth and produced blood lead levels close to the safety limits set for human exposure and similar to those that have been recorded in some children. The ontogeny of morphine antinociception using the tail immersion test and ketocyclazocine in the paw pressure test was studied in 10,21 and 30 day old rats. Perinatal lead exposure decreased the antinociceptive activity of both morphine and ketocyclazocine in 10 day old rats. Recovery of morphine antinociception occured by 21 days and ketocyclazocine antinociception by 30 days. Radioligand binding studies with [3H]DAGO were used to study the ontogeny of u-opioid receptors in 10,21 and 30 day old rats. Perinatal lead exposure was without effect on equilibrium dissociation constant or maximal binding capacity. Radioligand binding studies with [[3]H] DPDPE were used to study the ontogeny of 6 -opioid receptors in rats between 15 and 50 days. The affinity of the 6-opioid binding site for [[3]H] DPDPE was reduced by perinatal lead exposure but without accompanying changes in binding capacity. This effect of lead on s-opioid receptors was persistant and was observed in rats aged 15-50 days. Basal plasma corticosterone levels (measured fluorimetrically) were elevated by perinatal lead exposure in 45 and 60 day old rats but not in 30 day old rats. In addition the modulatory effect of morphine on stress induced elevations of corticosterone levels was also affected by lead exposure. A reduced effect of morphine was seen in 30 day old animals whilst an increased effect was seen in 60 day old animals. Locomotor activity (measured by photocell detection) of 10,21 and 30 day old rats was recorded over 1 hour during the dark phase of the light/dark cycle. Exploratory locomotor activity was reduced in lead exposed animals at postnatal day 10 and the hypolocomotor effect of morphine was also increased in 10 day old lead exposed animals. The opioid system is particularly sensitive to perinatal low level lead exposure and this is manifested in several aspects of physiological function. Possible mechanisms by which lead affects the development of the opioid system are discussed.
627

An examination of genetic and social variability in a work force exposed to benzene

Yardley-Jones, A. January 1988 (has links)
This study was carried out in order to investigate the human genetic effects of exposure to benzene in 66 male workers of a refinery population and the results compared with 33 control workers in the same refinery, not known to have had exposure to benzene. Questionnaires were used to determine various life style factors such as smoking, drinking and exposure to ionising radiation as examples of known confounding variables. In addition, experiments were designed to investigate the mechanism of benzene carcinogenicity using cell transformation techniques, together with a molecular dosimetry approach in an attempt to identify and quantify any interaction with benzene metabolites and DNA. The results from the human studies showed no difference between the groups when effects such as mitogen-induced blastogenesis, proliferative rate index, sister chromatid exchange and urine mutagenicity were measured. There was a suggestion of a decrease in mitogenic response with age in both exposed and control individuals in the mitogen induced blastogenesis experiments, which was consistent with other studies. Although no difference in the number of revertant colonies in strain TA 98 and 100 was demonstrated between the high and low urinary phenol groups there was a correlation between the number of revertants and the ages of the individuals as a whole. One statistical test used in the examination of the chromosome aberration data suggested a statistically significant increase in aberrations in the exposed group to the control groups, and this increase could be the result of benzene exposure. Cell transformation studies using C3H10T1/2 cell lines did not indicate that benzene had any initiating carcinogenic properties in vitro using the two stage model of carcinogenesis. Furthermore, molecular dosimetry studies using C[14]-labelled benzene in vivo demonstrated only a very weak interation between benzene metabolites and rat liver DNA. All the methods used in this study generated negative data except for that to detect chromosome damage. This method showed a slight increase in damage in exposed workers by comparison with the controls suggesting that benzene may be a weak clastogen at low doses.
628

Network effects, conformism and misbehavior in Brazilian classrooms

Santos, Luan Falcão Daniel January 2016 (has links)
SANTOS, Luan Falcão Daniel. Network effects, conformism and misbehavior in Brazilian classrooms. -2016. 79f. Dissertação (mestrado). - Universidade Federal do Ceará, Programa de Pós Graduação em Economia, CAEN, Fortaleza, 2016. / Submitted by Mônica Correia Aquino (monicacorreiaaquino@gmail.com) on 2017-07-28T19:24:46Z No. of bitstreams: 1 2016_dis_lfdsantos.pdf: 1161764 bytes, checksum: 657efde122aaf7a32fa71aa91069e159 (MD5) / Approved for entry into archive by Mônica Correia Aquino (monicacorreiaaquino@gmail.com) on 2017-07-28T19:25:15Z (GMT) No. of bitstreams: 1 2016_dis_lfdsantos.pdf: 1161764 bytes, checksum: 657efde122aaf7a32fa71aa91069e159 (MD5) / Made available in DSpace on 2017-07-28T19:25:16Z (GMT). No. of bitstreams: 1 2016_dis_lfdsantos.pdf: 1161764 bytes, checksum: 657efde122aaf7a32fa71aa91069e159 (MD5) Previous issue date: 2016 / For understanding how networks a ect the behavior of individuals, speci - cally the behavior os students in the last year of high school inside the classroom, we estimate a model of Network e ects, the Local-average model for two behavioral variables: doing an exam without being prepared and cheating in an exam, in order to understand how the behavior of individual's friends a ects his or her behavior. It was found a positive and statistically signi cant e ect for the network e ect of the probability of doing an exam without being prepared, and a positive, but not signi cant e ect for the network e ect of the probability of cheating in an exam. This result shows that policies or actions aiming the reduction of the probability of a student do an exam without being prepared have what is called social multiplier e ect, because besides this policy change the behavior of the student regarding this variable, his or her change of behavior a ects positively the behavior of people in his or her network. / Para entender de que forma as networks afetam o comportamento dos indiv duos, em espec co o comportamento de estudantes no ultimo ano do ensino m edio dentro da sala de aula, estimamos um modelo de Network e ects, o Localaverage Model para duas vari aveis comportamentais: fazer uma prova ou teste sem ter se preparado e colar em uma prova, a m de entender como o comportamento dos amigos de um indiv duo afeta o comportamento do mesmo. Encontrou-se uma efeito positivo e estatisticamente signi cante para o network e ect da probabilidade de se fazer uma prova ou teste sem ter se preparado, e um efeito positivo, mas n~ao signi cante para o network e ect da probabilidade de se colar em uma prova. Este resultado mostra que pol ticas ou a c~oes que visam a redu c~ao da probabilidade de um estudante fazer um exame sem se preparar tem o que se chama social multiplier e ect, pois al em dessa pol tica mudar o comportamento do estudante em rela c~ao a essa vari avel, sua mudan ca de comportamento afeta positivamente o comportamento das pessoas em sua network.
629

Kardiovaskulární účinky izoflavonoidů / Cardiovascular effects of isoflavonoids

Jančíková, Lenka January 2018 (has links)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology & Toxicology Student: Bc. Lenka Jančíková Supervisor: PharmDr. Jana Pourová, Ph.D. Title of diploma thesis: Cardiovascular effects of isoflavonoids Background: The aim of this thesis is to summarize existing findings about natural vegetable substances known as phytoestrogens-isoflavones and to map the results of latest studies focused on cardiovascular effects of isoflavones. Main findings: Available data suggest that isoflavones and their metabolites have positive effect on human organism. These include antiaterosclerotic, antimenopausal and anticarcinogenic effects and a positive effect on osteoporosis. Positive effect on cardiovascular system includes antihypertensive, anti-inflammatory, anti-angiogenic, antiproliferative and antiaggregating effects. On the other hand, there are studies that point out possible risks related to mainly long-term use of isoflavones. Nevertheless, even though the findings of cardiovascular effects are not always consistent, most of them confirm positive effects of isoflavones on cardiovascular system. Conclusion: Isoflavones and their metabolites are a very interesting group of substances with natural origin and carry a potential for possible development of new drugs. Therefore, they...
630

EFFECTS OF ASYMMETRICAL LIVE LOADS ON SIDESWAYS AND MOMENT AMPLIFICATION FACTORS OF STEEL MOMENT FRAME CONSIDERING P-DELTA INTERACTION

Neupane, Bibek 01 May 2016 (has links)
The P-delta effect, which is a second order effect, is experienced by a structure mostly when the structure is subjected to lateral forces like earthquake and wind. In addition to earthquake and wind loads, when the structure is subjected to various live load patterns other than symmetrical loading, the structure experiences side sway or lateral translation. In this thesis, P-delta effects due to symmetrical and asymmetrical live loads is studied on a three-bay, two-story steel moment frame. The main objective of this research is to investigate P-delta effects on the column which is subjected to critical load case. The effect is analyzed based on the value of the moment magnification factor, B2. Besides, the story drift due to asymmetrical loading is also investigated. For the purpose of this study, “Approximate Second-Order Analysis” specified in “Appendix 8” of AISC Steel Construction Manual (AISC 2011) is used to amplify the first order effects to account for the second-order effects in the steel moment frame. Additionally, computer software is used to calculate the first order moments and axial forces.

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