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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.
421

Response and time allocation on concurrent variable-interval schedules of signaled and unsignaled reinforcement

Everly, Jeffrey. January 2007 (has links)
Thesis (Ph. D.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains viii, 99 p. : ill. Includes abstract. Includes bibliographical references (p. 61-65).
422

Developmental studies in timed performance

Wilson, Carlene. January 1984 (has links) (PDF)
Includes errata Bibliography: leaves 242-254
423

Travelling-wave solutions for parabolic systems

Crooks, Elaine Craig Mackay January 1996 (has links)
No description available.
424

Mechanisms and applications of dioxirane chemistry

Ennis, Julie N. January 1998 (has links)
Dimethyldioxirane oxidises nitrogen-containing substrates. The sites of oxidation are generally the sp3 nitrogen atoms in the molecules although other reactive groups can be oxidised if present. An indication of the reactivity of different dioxiranes was obtained qualitatively from the polarographic peak reduction potentials and quantitatively by reaction with the model substrate 4-nitro-N,N-dimethylaniline. The polarographic peak potentials were shown to be of a similar order to those of typical acyclic peroxides. The rank order in terms of reactivity was shown to be methyl(trifluoromethyl)dioxirane > dimethyldioxirane > ethylmethyldioxirane. The rate of the reaction was not influenced by pH or ionic strength but was accelerated greatly by the presence of water. An explanation for this observation was proposed through consideration of dielectric constant and hydrogen bonding effects.
425

School phobia : in search of a syndrome

Conn, W. J. T. January 1987 (has links)
This study is concerned with children's anxiety regarding school attendance of which school phobia is the most extreme form. A literature cull identified features believed to typify the school phobics pattern of anxiety and these were included in a battery of instruments administered to a random sample of 225 boys and 261 girls between the ages of 11 and 16 years. This battery was also administered to a sample of 30 clinically defined school phobic boys and 19 school phobic girls. Four groups, validated by a series of Discriminant Function Analyses, emerged in this study. These groups are taken to represent a continuum of anxiety relating to school attendance from severe to anxiety free. Evidence is adduced for the need to evaluate boys and girls data separately. The groups were found to differ for both boys and girls in terms of age and ability but not social class or the number of other fears experienced though slight differences in the nature of fears emerged. Overall the girls groups more commonly reported fears. Difficulties with friendships emerged as highly significant. However there were sex differences in the importance of the age and sex of friends variables and in whether the friends come from the childs own school. Differences also emerged on a specially created Vulnerability in School measure but not on a General Satisfaction with School scale. Sociometric data reliably discriminates among the groups for both boys and girls though generally did not appear to have an impact on favoured spare time activity. The school avoidance strategy of pretending to be sick did not prove to be significant though recourse to truancy did - especially among the boys. Additionally, significantly more sleep and nighttime problems are revealed among the more anxious groups for both boys and girls. The significance of these and associated other findings are analysed and a tentative model of the anxious childs' situation in terms of theories of Stress and Gaping nominated as furnishing a possible synthesis.
426

Development of redox proteomics methods and the identification of redox-sensitive proteins in arabidopsis

Liu, Pei 13 April 2015 (has links)
Cellular redox homeostasis mediates a wide range of physiological and developmental processes. Various stresses trigger over-production of reactive oxygen/nitrogen species which leads to oxidative modifications of redox-sensitive proteins. Identification and characterization of redox-sensitive proteins are important steps toward understanding molecular mechanisms of stress responses. In the study, a high-throughput quantitative proteomic approach termed OxiTRAQ was developed for identifying proteins whose thiols undergo reversible oxidative modifications in Arabidopsis cells subjected to oxidative stress. In this approach, a biotinylated thiol-reactive reagent is used for differential labeling of reduced and oxidized thiols, and the biotin-tagged peptides are affinity-purified and labeled with iTRAQ reagents for quantitation. This approach allows identification of the specific redox-regulated cysteine residues in proteins and offers an effective tool for elucidation of redox proteomes. With this approach, we identified 195 cysteine-containing peptides from 179 proteins whose thiols underwent oxidative modifications in Arabidopsis cells following the treatment with hydrogen peroxide. A majority of those redox-sensitive proteins, including several transcription factors, were not identified by previous redox proteomics studies. Besides, this method was also used to identify proteins that underwent oxidative modifications in Arabidopsis cells subjected to 15 minute treatment of salicylate (a key signaling molecule in the plant defense pathway) or flg22 (a peptide from bacterial flagellin that induces pathogen associated molecular patterns-triggered immunity). In total, 127 peptides from 111 distinct proteins were identified as salicylate- and/or flg22-responsive redox-sensitive proteins. Among the identified redox sensitive proteins are many regulatory proteins including those involved in chromatin remodeling, transcription, nucleocytoplasmic shutting, and posttranslational regulation. Furthermore, in vivo 15N metabolic labeling method combined with a cysteine-containing peptide enrichment technique was applied to identify proteins that undergo oxidative modifications in plants in response to pathogen attack. The identification of redox-sensitive proteins provides a foundation from which further study can be conducted toward understanding the biological significance of redox signaling in plant stress response.
427

Diels-Alder routes to Prosopis alkaloids

Birkinshaw, Timothy Nicholas January 1987 (has links)
This thesis describes the investigation of the Diels-Alder reaction of the imine (140) with the diene (141) to give four products (142,143,156, 157). At low temperatures the enone (156) is the major product while at ambient temperature the bicyclic compounds (142) and (143) predominate. The reaction is highly solvent dependent, with the best results being obtained in benzene solution. Lewis acids appear to have little effect on the course of the reaction. The reaction of the imine (140) with the TBDMSO diene (159) gives the silyl enol ethers (160) and (161) as well as the above four products. Possible mechanisms are discussed. COOM. OSIM., In order to investigate asymmetric induction the 8- phenylmenthyl derived imine (194) was reacted with the diene (141) under a variety of conditions but no asymmetric induction was seen in the exo adducts, and only a small degree in the endo adducts. The bromination and Baeyer-Villiger oxidation of the ketone (142) were investigated and the resultant lactone (209) was converted into the bromide (258). ISOPROSOPININE A (84) ISOPROSOPININE B (S3) Several methods to prepare a suitable side chain for isoprosopinine A were investigated. The prosopis alkaloids isoprosopinine A (84) and B (85) were prepared by alkylation of the sulphones (252) and (266) with the bromide (258) followed by reductive removal of the N-tosyl and sulphone moieties with sodium amalgam. The imine (274) has been prepared and shown to undergo a Lewis acid catalysed imino-Diels-Alder reaction with the diene (141) to give the adducts (283) and (284). hCH,M=CHCOjM» (2T4) Alternative imines for asymmetric synthesis, such as (299) and (288) have been investigated. Preparation of the sulphinamide imine (299) has proved difficult. Attempts to carry out aqueous Diels-Alder reactions of the silyloxydiene (159) with iminium ions, generated in situ from amines, aldehydes and acids, have proved fruitless.
428

E0 and E2 decays of the excited 0'+ states in '78Se, '124Te, '172Yb and '200Hg

Subber, A. R. H. January 1986 (has links)
No description available.
429

Human motor performance and physiotherapy:effect of strapping, hot and cold pack treatments and strength training

Kauranen, K. (Kari) 01 February 1999 (has links)
Abstract Human motor performance and motor skills are essential aspects of various daily activities, and their importance is especially great in traffic, sports and unexpected situations. There is evidence that physically active subjects have better performance in some motor tasks (e.g. reaction time) than less active ones, and a few longitudinal intervention studies have shown that training improves certain aspects of motor performance, but there are also contradictory results. Despite the difficulty of improving motor performance, many physiotherapy programs and treatments are expected to do precisely that. However, the previous literature contains little information on these issues. The aim of the present doctoral project was to examine human motor performance (reaction time, speed of movement, tapping speed and coordination) and the effects of some of the most commonly used physiotherapy treatments on it in normal healthy volunteers. In addition, the reliability of the motor performance measurements performed with the HPM/BEP system is presented. Study I was a cross-sectional study of the population of Oulu, where 200 healthy randomly selected subjects (100 men and 100 women aged 21–70 years) were stratified by gender and by ten-year age group into ten groups. The test battery consisted of six motor performance tests for both hands and feet. The studies II, III and V were non-controlled intervention studies, and study IV was a cross-over intervention study. The participants in the studies were healthy, voluntary staff members (n = 14–30) of the Oulu University Hospital, and the interventions between the measurements consisted of strapping of the ankle and wrist joints (study II), hot and cold pack treatments of the hand (study III), one-hour hand strength training session (study IV) and a ten -week hand strength training program (study V). The results showed that motor performance was poorer in the older age groups in both genders. The average speed of movement and tapping speed values were higher for men than for women, but there were no gender differences in the coordination tests or the hand reaction time tests. All values (except the hand reaction times) were better for the dominant than the nondominant side. The strapping of the ankle and wrist joints decreased some aspects of the motor performance and muscle strength of these joints in healthy subjects. The hot pack treatment of healthy subjects caused only minor changes in the motor performance of the treated area, while the cold pack treatment decreased almost all of the measured aspects, and these changes were especially notable in fine motor movements. A one-hour hand strength training session decreased acutely muscle strength and EMG activity, but muscle fatigue had no effects on the motor performance functions of the hand. It seems that the feeling of incompetence to perform speed and accurate movements with fatigued muscles is mainly a subjective feeling, and that the real effect of muscle fatigue on motor performance is less than generally expected. A ten-week hand strength training period increased muscle strength and EMG activity in the trained muscles. There was also a suggestion that even non-task-specific training may improve some aspects of the motor performance of the hand, and an increase in the activation of motor units during muscle contraction may improve motor performance in some motor tasks. In addition, the results indicated that the HPM / BEP system is a potentially useful tool for studying motor performance, and the reliability of the system is acceptable.
430

Peroxidatic oxidation of luminol

Scowen, N. R. January 1985 (has links)
No description available.

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