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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.
351

An investigation into phenotypic variation and the ecology of the Sabota Lark Calendulauda Sabota

Mashao, Mmatjie Lucy January 2014 (has links)
Thesis (M.Sc. (Zoology) --University of Limpopo, 2014 / Refer to the document / The Department of Biodiversity at the University of Limpopo, and the National Research Foundation (NRF)
352

Erich Wolfgang Korngold’s Idea of the “Modern”: Developing Variation in the Piano Concerto in C Sharp, Opus 17

Huang, Shu-Yuan 05 1900 (has links)
This study examines the Piano Concerto in C sharp, Op.17 (1923), by Erich Wolfgang Korngold (1897-1957), in light of developing variation, techniques that transform motivic ideas and create musical continuity in this work. The troublesome reception history of Korngold’s piano concerto derives from its complex musical features, which have created difficulties in understanding and evaluating this piece. Consequently, critics and scholars often label the highly sophisticated yet tonal musical language in this piece a residue of Romanticism from the nineteenth century. In this document, in contrast, examination of motivic development and connections in Korngold’s piano concerto reveals thematic and structural coherence in light of Korngold’s idea of modernity. This study provides a historical and technical survey of developing variation and discusses Korngold’s implementation of these techniques in his early compositions and the piano concerto. By doing so, this study recognizes the progressive aspect in Korngold’s music.
353

Statistical methods for Mendelian randomization using GWAS summary data

Hu, Xianghong 23 August 2019 (has links)
Mendelian Randomization (MR) is a powerful tool for accessing causality of exposure on an outcome using genetic variants as the instrumental variables. Much of the recent developments is propelled by the increasing availability of GWAS summary data. However, the accuracy of the MR causal effect estimates could be challenged in case of the MR assumptions are violated. The source of biases could attribute to the weak effects arising because of polygenicity, the presentence of horizontal pleiotropy and other biases, e.g., selection bias. In this thesis, we proposed two works, expecting to deal with these issues.In the first part, we proposed a method named 'Bayesian Weighted Mendelian Randomization (BMWR)' for causal inference using summary statistics from GWAS. In BWMR, we not only take into account the uncertainty of weak effects owning to polygenicity of human genomics but also models the weak horizontal pleiotropic effects. Moreover, BWMR adopts a Bayesian reweighting strategy for detection of large pleiotropic outliers. An efficient algorithm based on variational inference was developed to make BWMR computationally efficient and stable. Considering the underestimated variance provided by variational inference, we further derived a closed form variance estimator inspired by a linear response method. We conducted several simulations to evaluate the performance of BWMR, demonstrating the advantage of BWMR over other methods. Then, we applied BWMR to access causality between 126 metabolites and 90 complex traits, revealing novel causal relationships. In the second part, we further developed BWMR-C: Statistical correction of selection bias for Mendelian Randomization based on a Bayesian weighted method. Based on the framework of BWMR, the probability model in BWMR-C is built conditional on the IV selection criteria. In such way, BWMR-C delicated to reduce the influence of the selection process on the causal effect estimates and also preserve the good properties of BWMR. To make the causal inference computationally stable and efficient, we developed a variational EM algorithm. We conducted several comprehensive simulations to evaluate the performance of BWMR-C for correction of selection bias. Then, we applied BWMR-C on seven body fat distribution related traits and 140 UK Biobank traits. Our results show that BWMR-C achieves satisfactory performance for correcting selection bias. Keywords: Mendelian Randomization, polygenicity, horizontal pleiotropy, selection bias, variation inference.
354

Matematiska läromedel i grundskolans åk 1-3 : En kvalitativ studie om val av läromedel, lärobok - konkret material - digitala verktyg

Kouyoumjian, Azniv January 2021 (has links)
Syftet med denna kvalitativa studie är att undersöka vilka läromedel yrkesverksamma 1-3 lärare använder i matematikundervisning och hur dessa läromedel väljs ut och används. Elevernas matematikinlärning och utveckling har stor samverkan med undervisningsmetoder och val av läromedel. Begreppet läromedel kommer i studien handla om allt material som används i undervisning för att främja elevers matematiklärande. I studien har jag intervjuat fem 1-3 lärare. Lärarnas svar har tolkats med sociokulturellt perspektiv och kommit till resultaten att: det finns många olika faktorer och förutsättningar som påverkar lärarens val av läromedel i matematikundervisningen. Utifrån lärarnas beskrivningar har jag även sett deras kunskapssyn och likheter i deras val och användning av varierande läromedel vid matematikundervisning.
355

Interaktiva skrivtavlor i matematikundervisning : Lärares reflektioner kring den pedagogiska, didaktiska samt varierade användningen av interaktiva skrivtavlor i matematikundervisningen. / Interactive Whiteboards in mathematics education : Teachers reflections regarding pedagogical, didactic and variated usage of Interactive Whiteboards in mathematics education.

Kusserow, Ida, Enehöjd, Frida January 2020 (has links)
Detta är en studie där lärares beskrivningar kring användandet av den interaktiva skrivtavlan (IST) i matematikundervisningen lyfts fram genom semistrukturerade intervjuer. Utifrån tidigare forskning skapades tre kategorier som representerar de användningsområden som hittades för den interaktiva skrivtavlan. Dessa tre kategorier användes sedan för att analysera intervjusvaren från informanterna. Kategorierna som togs fram var pedagogik, didaktik och variation. Genom intervjuerna med fyra lärare framkom det att lärarna hade en generellt positiv inställning gentemot IST och att den användes frekvent samt att det fanns många användningsområden för den interaktiva skrivtavlan i matematikundervisningen. Slutsatserna blev att IST bidrar till variation i matematikundervisning och kan nå flera olika inlärningsstilar om lektionerna planeras didaktiskt med detta i åtanke. IST blir ett pedagogiskt verktyg eftersom det förtydligar undervisningsinnehållet, bidrar till diskussioner och ett interagerande mellan elever och lärare kring det som visas upp på tavlan. Lärarna kunde även få utökad utbildning kring användandet av IST för att kunna utveckla de potentiella användningsområdena inom matematik som ännu inte används på grund av bristfällig utbildning.
356

Not Enough Skeletons in the Closet: Collections-Based Anatomical Research in an Age of Conservation Conscience

Bell, Christopher J., Mead, Jim I. 01 March 2014 (has links)
The emergence of new technologies and improved computing power helped to introduce a renewed vitality in morphological research in recent decades. This is especially apparent in the new advances made in understanding the evolutionary morphology of the skeletal system in extinct and extant squamate reptiles. The new data generated as a result of the recent increase in attention are relevant not only for systematic analyses but also are valuable in their own right for contributing to holistic perspectives on organismal evolution, mosaic evolution in the rates of change in different anatomical systems, and broader patterns of macroevolution. A global community of morphological researchers now can share data through online digital collections, but opportunities for continued advance are hindered because we lack even basic data on patterns of variation of the skeletal system for virtually all squamate lineages. Most work on skeletal morphology of squamates is based on a sample size of n=1; this is an especially noticeable phenomenon for studies relying on X-ray computed tomography technology. We need new collections of skeletal specimens, both material and digital, and new approaches to the study of skeletal morphology. Promising areas for continued research include the recent focus on skeletal elements not traditionally included in morphological studies (especially systematic analyses based upon morphological data) and efforts to elucidate patterns of variation and phylogenetically informative features of disarticulated skeletal elements. Anat Rec, 297:344-348, 2014.
357

Performance Characteristics of Scintigraphic Colon Transit Measurement in Health and Irritable Bowel Syndrome and Relationship to Bowel Functions

Deiteren, A., Camilleri, M., Bharucha, A. E., Burton, D., McKinzie, S., Rao, A. S., Zinsmeister, A. R. 01 April 2010 (has links)
Background The inter- and intra-subject variations of scintigraphy, which are used to identify colonic transit disturbances in irritable bowel syndrome (IBS), are unclear. The relationship between colonic transit and bowel functions is incompletely understood. To assess inter- and intra-subject variations of scintigraphic colonic transit measurements in 86 IBS patients and 17 healthy subjects and to quantify the relationship between colonic transit and bowel symptoms in 147 IBS patients and 46 healthy subjects. Methods Data from participants with multiple colonic transit measurements were analysed. Primary end points were colonic filling at 6 h (CF6h) and geometric center (GC) at 24 and 48 h for colonic transit. Bowel functions were assessed by daily stool diaries. Key Results Inter- and intra-subject variations were greater for small intestinal than colonic transit. Overall, inter- and intra-subject variations were relatively narrow for colonic transit (both GC24h and GC48h, with lower COV at 48 h); there was little intra-subject variation in health and IBS-constipation over a period of ≤3 weeks and over 2.0 years (median, range 0.1, 11.0 years). Significant intra-individual differences in GC24h were observed only in IBS-D patients. Colonic transit was significantly associated with stool form (accounting for 19-27% of the variance), frequency (19%), and ease of stool passage (12%). Conclusions & Inferences Despite inter-subject variation in scintigraphic colonic transit results, the intra-subject measurements are reproducible over time in healthy volunteers and patients with IBS; significant changes in colonic transit at 24 h were observed only in IBS-D. Colonic transit is associated with stool form, frequency and ease of passage.
358

The influence of a changing environment on the breeding biology and diet of Kelp Gulls (Larus dominicanus vetula) in Plettenberg Bay, South Africa

Witteveen, Minke January 2015 (has links)
We live in a constantly changing world, where recent human-induced changes and climate change affect virtually every component of the Earth's surface and systems. Coastal ecosystems are particularly at risk, as one of the most utilised and urbanised of natural systems worldwide, as well as being at risk from sea level rise. This will degrade or even destroy many feeding and breeding sites. Those species colonising new habitats in an attempt to escape rising sea level and climate change related threats, will be competing for space with the growing human population and urbanisation. Although 97 of 346 seabird species (28%) are globally threatened, 57 (17%) have increasing populations, including 17 gulls (Larinae). The Kelp Gull Larus dominicanus is a cosmopolitan species with an increasing population worldwide. Kelp Gulls in southern Africa L. d. vetula are one of 15 seabird species that breed in the region, and one of only five breeding seabirds listed as Least Concern in the region. Three Kelp Gull breeding colonies in Plettenberg Bay, Western Cape, were surveyed to provide an updated count for this area. A combination of direct counts and the trial use of an unmanned aerial vehicle (UAV),were used as methods of counting nests. The direct monitoring of nests allowed for the effect of different microhabitats on the breeding performance of Kelp Gulls to be investigated, which has implications for their ability to adapt to future habitat changes. The importance of anthropogenic food items in the diet of Kelp Gulls breeding in Plettenberg Bay was explored through the use of regurgitated pellets of indigestible matter, and chick regurgitations, and how this is reflected in the time spent in various areas as shown by GPS loggers and point counts in urban areas. Another aspect of the urban adaptation of Kelp Gulls is the incorporation of anthropogenic debris in their nests, which was examined at eight breeding colonies throughout the Western Cape.
359

A comparative study of variation in stress and intonation patterns in the spoken English of some selected Yoruba and Zulu university undergraduate students

Ayoola, Oluwafunmiso Moses January 2016 (has links)
A thesis submitted to the Faculty of Arts in fulfillment of the requirements for the Degree of Doctor of Philosophy (Dphil) in the Department of English at the University of Zululand, 2016 / English is a world language. The serious concern for the study and the adaptation of English to the world in general and Nigerian and South African milieu in particular started over a century ago. The study of English has been given new dimension through debates held at conferences and workshops over the issue of standard or correctness which seemingly emerged in different countries of the world. The growing divergence and convergence of English language in the world today paved way for variations in use particularly at the level of spoken words. The present work is one of the new crops of studies that attempts to identify and characterise the varieties of spoken English of our time. The study deals with a comparative study of variation in stress and intonation patterns in the spoken Yoruba and Zulu English. It seeks to identify the nature of Yoruba and Zulu spoken English and to account for the varieties that exist within the continuum. The study also aims to generate a pedagogical approach for the presentation of the appropriate spoken English inputs which is necessary for characterizing Yoruba and Zulu spoken English. The essence is to see the growing divergence and convergence of spoken English in these two speech communities. The subjects of the study were 120 Yoruba and Zulu speakers of English. The speakers were selected using a stratified random sampling technique. The main criteria for stratification were level education in English language and the linguistic group of the speakers. Two British (male and female) were used as the control. The elicitation instruments used for the collection of data were face to face interviews and materials for reading. The materials were divided into three parts: the word list, the sentence and a continuous reading passage. The three reading materials contained the target phonological variables which the researcher was interested in. The subjects were made to read each of the materials one after another and were recorded using PRAAT, a program for doing phonetic analyses and sound manipulations by Boersma and Weenink (2010). The study employed the framework of Metrical Phonology in the representation of stress. This was based on the view of rhythm proposed by Liberman (1975) and later developed into a theory by Liberman and Prince (1977). In this theory, the syllables are represented as having strong (S) and weak (W) stresses. The assignment of strong and weak nodes is determined by two rules: a Lexical Category Prominence Rule (LCPR), which operates on simple and compound words and Nuclear Stress Rule (NSR), which covers phrases and sentences. The analysis of intonation was based on Pierrehumbert’s (1980) model of intonation which supports the independence of stress pitch. In this system, intonation contours are seen as pitch accent and are described in terms of two levels: High and Low tones. The rank of difference was calculated using Wilcoxon (1985) Statistical Test. The study revealed that the spoken Yoruba and Zulu English featured more prominent syllables than spoken British English. The difference occurred mostly at the level of syllable and utterance duration. With regard to intonation, the study showed that the spoken Yoruba English is different from Zulu counterparts and those of the British. While the British used more directional tones, the Yoruba and Zulu used unidirectional tones. The study also showed that isiZulu speakers exhibited instances of vowel lengthening system while the Yoruba speakers demonstrated the tendency to use reduced vowel system. The varieties of spoken Yoruba English are different from those of isiZulu spoken English and in some measure significantly different from the British who served as the control group (see analyses on chapters five and six). The claim that high tones are associated with lexical words and low tones with structural words as posited by Well (1982), and Gut and Milde (2000) was not conclusively accepted by the data in this study. This study contends that the observed stress and intonation patterns in the spoken of some selected Yoruba and Zulu speakers could be considered as are part of ‘Standard educated Yoruba and Zulu spoken English’. The acoustic analyses of stress and intonation clearly showed that in isiZulu spoken English, syllable duration particularly the unstressed syllables are relatively longer than in the Yoruba and those in the native variety of spoken English being represented by the control group.
360

Spatial Temperature Variation in Refrigerated Road Transport

Phoenix, Joseph D. 01 May 2015 (has links)
This study evaluated the temperature variability that existed in refrigerated table grape consignments over a two-day journey from two suppliers in southern Spain, to client managed facilities in England. In order to inhibit senescence, perishable foods are transported in temperature-controlled transport to maximize shelf life. However, thermal dynamics suggests that uniform spatial temperature is not necessarily achieved despite a constant set point. As fruit exposed to suboptimal temperatures is more likely to exhibit undesirable quality issues, knowledge of spatial temperature can direct quality control team members to these potentially problematic pallets within an inbound shipment. Warmer temperatures were identified on the passenger side of both trailers, at the rear of both trailers, and in lower pallet layers. Furthermore, heightened temperature was recorded in lower pallet layers in close proximity to the refrigeration return unit. The Supplier 2 shipment, set at 4oC, exhibited more spatially uniform temperatures compared to the Supplier 1 shipment set at 1oC. This implies that an operational compromise may exist: a higher but more uniform temperature or a lower but more variable temperature. In addition, analysis of airflow distribution suggested that airflow could be improved specifically in lower pallet layers and towards the rear of the trailer. Improved circulation will promote improved temperature uniformity for quality maintenance.

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