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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.
161

High resolution electronic spectroscopy of transient species

Elks, John Marcus Francis January 2001 (has links)
No description available.
162

Investigation of the Effects of Xenoestrogens on the Protein Levels of the Estrogen Receptors

Lang, Claudia Nicole January 2006 (has links)
There has been an increase in reports of male reproductive disorders that include male infertility and testicular cancer worldwide. It has been suggested that agents such as xenoestrogens could be responsible. Xenoestrogens are chemical compounds that mimic the action of estrogens by binding to the estrogen receptors (ERs). The response ofa testicular cell line to estrogenic pesticides was examined. The effect of estrogenic pesticides on the growth and protein levels of ERα and ERβ of mouse Sertoli cells was investigated. Pyrethroids are widely used insecticides due to their insecticidal potency and low mammalian toxicity. In this study, the estrogenicity ofpyrethroid chemicals were tested using the yeast estrogen screen (YES) assay. The toxic effects of the pyrethroid compounds cypermethrin, 3-(4-hydroxy-phenoxy)benzyl alcohol (metabolite of permethrin), and the commercial product (Ripcord Plus) were evaluated. The Sertoli cells were exposed to pyrethroids at concentrations of 0.36 nM and 36 µM (cypermethrin and Ripcord Plus), and 0.69 nM and 69 µM (metabolite) for 100 h. The expression of the ERs was analysed through the use of Enzyme Linked ImmunoSorbent Assay (ELISA) experiments. The most toxic pyrethroid was the metabolite, followed by Ripcord Plus then cypermethrin. Overall the exposure of the cells to cypermethrin (36 µM), Ripcord Plus (36 µM) and the metabolite (69 µM) caused a significant decrease (p<0.05) in ERα levels. In the cultures exposed to the metabolite (69 µM), there was also a significant increase in ERβ levels. There appears to be a relation between cell toxicity and an increase in ERβ levels, which supports the theory that ERβ promotes apoptosis. Pyrethroids are rapidly excreted from the body, and it is unknown if there is accumulation in the male testes. Male fertility could be affected through molecular mechanisms involving the ERs, should cells in the male testes be exposed to these pyrethroids at physiologically relevant concentrations.
163

Bioecology, infestation levels and control of fruit damaging common sawflies (hymenoptera, symphyta, tenthredinidae) in apple and plum orchards / Tikrųjų pjūklelių (hymenoptera, symphyta, tenthredinidae) – vaisių kenkėjų bioekologija, žalingumas ir kontrolė obelų ir slyvų soduose

Tamošiūnas, Rimantas 20 June 2014 (has links)
The relevance of the study. Apple sawfly (Hoplocampa testudinea Klug), black plum (Hoplocampa minuta Christ.) and yellow plum (Hoplocampa flava L.) sawflies (Hymenoptera, Symphyta, Tenthredinidae) are serious and widespread pests of apple and plum fruits. Dock sawfly (Ametastegia glabrata Fall.) is a non-specialized apple pest and its larvae feed generally on leaves of Chenopodium sp. and Polygonum sp.; however, occasionally mature fruits at harvest are found damaged by larvae of this insect. Former studies indicated that these species caused significant damage to apple and plum yield in Lithuania in mid-late XX century. However, at that time the setup of apple and plum genotypes cultivated was completely different from conventional orchard management techniques and cultivars at present time. Therefore, the growing diversity of cultivated fruit-tree genotypes leaves gaps in knowledge as to how apple and plum sawflies will affect some of the newer cultivars. In Lithuania, no data on susceptibility of economically important apple and plum cultivars to sawfly damage in commercial orchards is available. A shift towards integrated pest management and development of organic fruit farming poses new challenges to apple growers and plant protection specialists. According to the requirements of these management strategies, the use of synthetic pesticides must be reduced or is not allowed at all. Several reports from countries where the use of synthetic insecticides was significantly... [to full text] / Temos aktualumas. Obuolinis pjūklelis (Hoplocampa testudinea Klug), slyvinis juodasis (Hoplocampa minuta Christ.) ir slyvinis geltonasis (Hoplocampa flava L.) pjūkleliai, priklausantys plėviasparnių (Hymenoptera) būriui, tikrųjų pjūklelių (Tenthredinidae) šeimai, yra reikšmingi specializuoti obelų ir slyvų vaisių kenkėjai, paplitę viso pasaulio obelų ir slyvų auginimo regionuose (Velbinger, 1939; Alford, 2007; Vincent, Belair, 1992). Rūgtinis pjūklelis (Ametastegia glabrata Fall.) priklauso tai pačiai šeimai – ir, nors jo lervos pagrindinai minta balandinių ir rūgtinių augalų lapais, tačiau dažnai aptinkama ir šio vabzdžio lervų pažeistų obuolių. Anksčiau Lietuvoje obuolinis bei slyviniai pjūkleliai būdavo žalingi senesniuose soduose. Susidarius palankioms sąlygoms masiškai plisti arba vaismedžiams derant negausiai, šių kenkėjų daroma žala viršydavo kitų pagrindinių obelų ir slyvų kenkėjų, tokių kaip obuolinis (Cydia pomonella L.) ar slyvinis (Grapholita funebrana Treits) vaisėdžiai, daromą žalą. Pavyzdžiui, slyviniai pjūkleliai susidarius palankioms sąlygoms – šiltam ir ankstyvam pavasariui, sunaikindavo daugiau kaip 60% kai kurių veislių slyvų vaisių derliaus (Заянчкаускас, 1958). Per paskutinius du dešimtmečius Lietuvoje senuosius sodus pakeitė intensyvūs ir ekologiniai sodai, kuriuose sodinami naujų veislių vaismedžiai su žemaūgiais poskiepiais. Pasikeitus ūkininkavimo sąlygoms, keičiantis aplinkos sąlygoms, šylant klimatui, keičiasi kenkėjų rūšinė sudėtis bei žalingumas... [toliau žr. visą tekstą]
164

Sport psychological skills that distinguish between u/19 club rugby players of different participation levels and positional groups / Michelle Andrew.

Andrew, Michelle January 2006 (has links)
Sport psychological skills play an important role in sport performance. Evidence further suggests that the psychological skill levels may be influenced by the particular playing position. One hundred and eighty u/19 rugby players from the PUK Rugby Institute (average age: 18.79 +- 0.28 years) were tested during the 2003-2005 rugby seasons by means of the Competitive State Anxiety Inventory-2 (CSAI-2), Psychological Skills Inventory (PSI), Athletic Coping Skills Inventory-28 (ACSI-28), as well as a questionnaire dealing with psychosocial factors influencing participation and performance in rugby. Players from the 2004 and 2005 seasons (n=120) were first divided into two groups (top- and lower ranked players) of 60 players each. Effect size results (practical significance) revealed moderately significant differences between the two groups, with the top ranked players outscoring their lower ranked counterparts in self-confidence, general coping resources, coping with adversity, average psychological skills score, as well as the effect of team members/team spirit, coaches and financial aspects on participation and performance. These results confirm that sport psychological skill levels and related psychosocial factors can distinguish between rugby union players of different participation levels. Secondly, the total subject group (n=180) was divided into seven positional groups (props, hookers, locks, loose trio, half-backs, centres and back three). These groups were compared by means of effect sizes (practical significance) for each of seven sport psychological skills as measured with the PSI. Moderate (46) and large (20) practically significant differences were reported for the 147 inter-positional comparisons. The results show that the half-backs and hookers consistently outperformed the other three positional groups, while the props, locks and back three often showed the lowest skill levels. While these results are discussed in reference to practical implications for future position specific sport psychological skills training sessions, they clearly show that sport psychological skill levels differ from one position to another. / Thesis (M.Sc. (Human Movement Science))--North-West University, Potchefstroom Campus, 2006.
165

Roles of Clostridium difficile cell wall and flagellar proteins in pathogenicity and innate immunity

Dehlawi, Saied Waheed January 2012 (has links)
The number of cases of Clostridium difficile infection (CDI) has been increasing globally. CDI is the main cause of nosocomial diarrhoea, which may be life-threatening in complicated cases, and also costs the health care societies millions of pounds annually. The predominant types and their resistance to antibiotics have been changing and one of the major selective pressures which causes this is antimicrobial use. Although much is known about the role of the toxins in pathogenesis of CDI, the role of immunogenic cell wall components is unclear. They may play a role in colonisation and pathology and a study of these could clarify the infection process. It is therefore important to study the immune responses against these bacterial wall components from different strains and their effects on stimulation of leukocytes to produce cytokines and chemokines. This study was divided into four parts: 1. An epidemiological study to determine frequencies of the predominant types of C. difficile, thus 140 C. difficile isolates from surgical patients and their environment during 2009 were investigated to define their PCR ribotype. This utilised capillary sequencing gel electrophoresis for their analysis. 2. The determination of antimicrobial susceptibility to six antibiotics (ampicillin, erythromycin, tetracycline, metronidazole, moxifloxacin and vancomycin) was assessed and MIC determination by agar dilutions. 3. Investigation of host immunity to molecules with conserved molecular patterns. Surface-layer proteins (SLPs), lipocarbohydrate (LC) and flagellar proteins were separated and purified from five ribotypes of C. difficile (001, 002, 027, 078 and106) predominant in Scotland. a) The immune responses to these molecules were assessed by ELISA by exposing serum of patients and healthy donors and measuring specific IgG levels. b) Innate immunity was investigated by distinguishing responses of a macrophage cell line (THP1) to the above molecules. Induction of interleukins (IL)-1β, IL-6, IL- 8, IL-10 and IL-12 interleukins and TNF-α was detected by ELISA. In this study 15 different ribotypes were identified. The most frequent were 001, 020, 106 ribotypes (52.8%, 7.4% and 5.7%), respectively, while 13 isolates could not be assigned a ribotype. However, all isolates were sensitive to vancomycin, metronidazole and moxifloxacin, but 74.28% of isolates were resistant to erythromycin. The IgG level against bacterial antigens (SLPs, LC and flagella proteins) in donors’ serum showed almost normal distribution to all antigens from the different ribotypes and the sensitivity of the assays was increased by raising the concentration of antigens. Levels to SLPs were generally the highest, but the flagellar protein exceeded the SLPs of the 027 ribotype. The donors, controls, patients and carrier sera gave similar results. The greatest induction of interleukins was obtained using 50μg of antigen with the THP-1 cells activated with 50ng of PMA. The highest induction of all antigens was for IL-10. The highest values for the control LPS was with IL-12. But the best effect for SLPs of 027 was for IL-10 (109.1ng/ml), while the weakest for TNF for SLPs of 027 (4.7ng/ml). In general the IL-1β, IL-6, IL-8 and TNF concentrations ranged from 4.7-60ng/ml for all antigens and in contrast IL-12 and IL-10 average ranged 11- 109.1ng/ml. To conclude, the prevalence of C. difficile and their antibiotic susceptibility are constantly changing. IgG antibodies to SLPs and flagellar proteins from the hypervirulent ribotype 027 were highest in the community and hospitalized individuals. The molecules of conserved molecular patterns are immunogenic with various levels of response in the monocytic THP1 cells. SLPs were best in inducing interleukins. Flagellar proteins from 027 ribotypes accompanied SLPs in IL-10 induction levels. Consequently SLPs and flagellar proteins from 027 ribotypes appeared the best immunogenic bacterial molecules.
166

D-D and D-T Neutron Excitation of Energy Levels in Cs133

Dawson, Horace Ray 01 1900 (has links)
The purpose of this experiment was to make positive assignment of the Cs133 energy levels excited by the inelastic scattering of neutrons.
167

Impact of Job Classification Level on Perceived Empowerment Level in a Work Setting

Thornton, Renita 08 1900 (has links)
Empowerment, which has been described as both a means of effecting higher and more efficient quality work outputs and a means of facilitating greater freedom in the workplace combines elements of philosophy, psychology, and management theory. The perceptions of the present empowerment level of 3500 employees of a division of a major corporation were analyzed using data from an empowerment survey. The results were examined using correlational and factorial measures to test the structure of the survey. ANOVA and pair-wise comparisons were used to examine group differences on five subscales of the survey based on employee level in the organization. Significant differences were found in almost all categories. Rank order for the three levels differed from previous findings, perhaps due to empowerment thrusts.
168

Speech intelligibility in noise of normal-hearing and hearing-impaired individuals wearing E-A-R plugs

Wade, Mary A. January 1986 (has links)
Call number: LD2668 .T4 1986 W23 / Master of Arts / Communication Studies
169

A mixed method assessment of the association between young mother’s education attainment and child malnutrition in rural Malawi

Sanga, Linice Rumbani January 2018 (has links)
Magister Artium (Development Studies) - MA(DVS) / Malnutrition is a big public health concern in Malawi. Almost 40% of under-five children in Malawi suffer from malnutrition. Children born to poor mothers with low education levels have higher chances of being malnourished. Great disparities are also seen between children born in rural areas and those born in cities and towns. This research examines the linkages between mothers’ education attainment and child malnutrition. The Capability Approach and the UNICEF Conceptual Framework on child malnutrition was used in ascertaining how education affects mother’s choices and practices on child’s health and nutrition. The Explanatory Sequential Mixed Method Design was used. Combining elements of Qualitative and Quantitative research methods to provide depth and breadth of how mother’s education affects child’s health and nutrition. Findings from the Quantitative analysis of the 2015-2016 Malawi Demographic and Health Surveys data on child malnutrition and women’s education, informed the qualitative approach. The results guided in purposively sampling participants for the Qualitative research. Stata 14 was used to analyse quantitative data. Themes were drawn from the qualitative data and an analysis of the recurring themes was done using Atlas.ti 8. The study found that there is an association between mother’s education and child health. Children born to mothers with secondary and higher education qualification have lower odds of malnutrition and poor health. Inadequate knowledge on nutrition, food and nutrition insecurity, poverty and low welfare status of mothers with low education levels are contributing factors to high incidences of malnutrition among their children. Malawi needs to invest in girl’s education; particularly in rural areas where many girls do not transition to secondary school.
170

Longitudinal modelling of water levels of the Okavango River

Unandapo, Lazarus Pendapala January 2016 (has links)
A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. May 30, 2016. / In statistics, a model is as good as the data fed to it. Data about hydrological events continues to grow rapidly over the years, with different variables being recorded on a continuous scale. These variables can be interpreted and used in a different manner among disciplines. Thus, choosing the right variables and interactions among variables is an important statistical step in building a good and accurate model. This dissertation involved the development of a statistical model which can be used to predict weekly water level within the Okavango river in northern Namibia. The parameters of the statistical mixed model were estimated based on two methods for longitudinal data, the Generalised Estimating Equations (GEE) which is a well known method of parameter estimation in longitudinal data analysis when the observed variables are correlated, and the Restricted Maximum Likelihood Estimation (REML) which is a likelihood based approach method, unlike the GEE. Using cross-validation and a simulation study, the GEE method of estimation was found to be less accurate and inconsistent in terms of prediction of parameter estimation of water level while the well known REML was found to predict the water level with a good degree of accuracy, consistency and with lower variance. Parameters from a simulation study have also shown less bias in REML method and predicted the cross-validation test-set with less bias. / GR 2016

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