By definition "adaptability" is the ability of living systems to cope with change. Genetic adaptability requires the production of genetic variation. The view that variation production is undirected or random, i.e. unconnected with selection, implies that selection does not tailor genetic adaptability. But many genetic elements are known to modify processes of variation production, and secondary selection can act on them, so that view is not justified. Over the longer term, natural selection 'favors' properties important, in maintaining immediate fitness, as well as properties important for persistence in the short term. Genetic adaptability is less important in the short term, and is ignored in models based on short term definitions of fitness (e.g. relative effective rate of increase). If "fitness" is to be "the properties favored by natural selection", then its definition should be time scale dependent. Currently prevalent short term definitions of the action of natural selection should not be allowed to hamper consideration of the role of slow processes in determining long term evolutionary patterns. A review of patterns in genome size, and the existing explanations for them, reveals that most explanations are based on notions of adaptedness to the state of the environment. An explanation of genome size patterns based on the rate of change of environments is proposed. It is hypothesized that part of the genome is involved in regulating variation production, and that more DNA means slower production of additive genetic variation. This new hypothesis is simple, general, and testable, but requires more evidence. The question is raised of whether genomes might be organized to facilitate the adjustment of genetic variation production by natural selection. / Science, Faculty of / Zoology, Department of / Graduate

Sense amplifiers are important circuit components of a dynamic random access memory (DRAM), which forms the main memory of digital computers. The ability of the sense amplifier to detect and amplify voltage signals to correctly interpret data in DRAM cells cannot be understated. The sense amplifier plays a significant role in the overall speed of the DRAM. Sense amplifiers require matched transistors for optimal performance. Hence, the effects of mismatch through process variations must be minimized. This thesis presents a research which leads to optimal nanoscale CMOS sense amplifiers by incorporating the effects of process variation early in the design process. The effects of process variation on the performance of a standard voltage sense amplifier, which is used in conventional DRAMs, is studied. Parametric analysis is performed through circuit simulations to investigate which parameters have the most impact on the performance of the sense amplifier. The figures-of-merit (FoMs) used to characterize the circuit are the precharge time, power dissipation, sense delay and sense margin. Statistical analysis is also performed to study the impact of process variations on each FoM. By analyzing the results from the statistical study, a method is presented to select parameter values that minimize the effects of process variation. A design flow algorithm incorporating dual oxide and dual threshold voltage based techniques is used to optimize the FoMs for the sense amplifier. Experimental results prove that the proposed approach improves precharge time by 83.9%, sense delay by 80.2% sense margin by 61.9%, and power dissipation by 13.1%.

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)

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.

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.

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.

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.

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.

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.

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.