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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.
681

Optimierung einer Lipase aus Bacillus subtilis mit neuen Methoden der gerichteten Evolution

Funke, Susanne Aileen. Unknown Date (has links)
Universiẗat, Diss., 2005--Düsseldorf.
682

The scriptures on the stand a perspective on the Scopes Trial /

Oshman, Mark A. January 1985 (has links)
Thesis (Th. M.)--Temple Baptist Theological Seminary, 1985. / Bibliography: leaves 91-95.
683

Pathways to Sustainability: Evolution or Revolution?

Ashford, Nicholas January 2002 (has links)
No Abstract Provided
684

The evolution of mating cues in a beetle hybrid zone : causes of geographic variation in cuticular hydrocarbon profiles /

Zack, Rachel M.S. January 2008 (has links)
Thesis (M.S.)--Western Washington University, 2008. / Includes bibliographical references (leaves 64-70) Also available online.
685

The place of evolution in the philosophy of Roy Wood Sellars

Martinson, Paul January 1957 (has links)
Thesis (M.A.)--Boston University / The question --- whether a biological concept, such as evolution, can have a profound effect in such a remote field of study as professional philosophy --- must begin with a discussion of what evolution means to biologists, and did mean at the time the philosopher in question was formulating his philosophy. The names of Lamarck, Darwin, and DeVries stand for three theories of the method of evolution, current at the time Sellars was formulating his metaphysics; and there was no acceptable way of choosing among them. However, all were agreed that evolution had occurred and by evolution they meant a continuous chain of descent accompanied by modification of inheritance until new species had been formed. Since Sellars does, as most philosophers do, have his own vocabulary of special terms, the need of a glossary is indicated, to contain terms as: thing, existent, datum, content, perception, category, thinghood, intuit, knowledge, object, correspond, physical, law, connection, continuity, structure, function, organism, system, emergence, time, explanation, history, and cumulation. The thorough explanation of these terms acts to describe, to a considerable extent, Sellars' philosophy. However, another separate chapter is necessary to give an adequate picture of Sellars' metaphysics, epistemology, unification of the sciences, approach to the mind-body problem, emphasis on evolution, and rejection of God. [TRUNCATED]
686

Granite petrogenesis and crustal evolution studies in the Damara Pan-African orogenic belt, Namibia

McDermott, P. F. January 1986 (has links)
Major and trace element data for Damara granitoids distinguish three geochemically distinct granitoid groups, - crustal-melt granitoids, calc-alkaline granitoids and within-plate granitoids. The overwhelming majority of the Oamara granitoids are peraluminous crustal-melt leucogranites which have elevated <sup>87</sup>Sr/<sup>86</sup>Sr ratios (> 0.710) and old model Nd ages (~ 2.0 Ga). Calc-alkaline diorites are metaluminous and have the lowest <sup>87</sup>Sr/<sup>86</sup>Sr ratios (0.704 - 0.707) and model Nd ages (OM) in the range 1.1 -1.7 Ga. Within-plate granitoids are characterised by elevated high-field strength (HFS) abundances and have model Nd ages (OM) in the range 1.1 - 1.6 Ga. All Damara granitoids have model Nd ages (OM) older than about 1.0 Ga suggesting that intracrustal reworking was the dominant process and crustal growth was negligible. Damara granitoids define a hyperbola on an ∈ Sr vs. ∈ Nd diagram but cannot be modelled as simple binary mixtures between old continental crust and depleted mantle end-members. An episodic intracrustal remobilisation model is proposed to explain the hyperbola defined by granitoid data on an ∈ Sr vs. ∈ Nd diagram. Within the 10 km thick Damara metasedimentary pile <sup>87</sup>Sr/<sup>86</sup>Sr ratios increase systematically with depth. This trend is accompanied by a decrease in <sup>143</sup>Nd/<sup>144</sup>Nd ratios. Model Nd ages (CHUR) for the stratigraphically oldest Damara metasediments (Nosib Group) are about 2.0 Ga whereas the younger metasediments (Kuiseb Formation and Nama Group) have model Nd ages (CHUR) about 1.0 Ga reflecting sediment input from younger source terrains. The ratio of model ages (T<sup>Nd</sup><sub>CHUR</sub>/T<sup>Sr</sup><sub>BE</sub>) is used as an index of intracrustal reworking since it provides a measure of Rb/Sr fractionation (increases) relative to SmlNd fractionation. The older Damara metasediments (Nosib Group) have the highest model age ratios suggesting that their source terrains have suffered the largest amount of intracrustal reworking. However, the rate of intracrustal reworking was greatest in source terrains sampled by the younger Damara metasediments (Kuiseb Formation and Nama Group). This suggests that the rate of intracrustal reworking increased through time in the interval (2.0 - 1.0 Ga) in this segment of continental crust.
687

Gene, Organism and Environment: Understanding Patterns of Genome Evolution in Bacteria and Bacteriophage

Perry, Elizabeth 03 October 2013 (has links)
For my dissertation research, I used a model system of bacteria and bacteriophage to study patterns of genome evolution. I performed whole-genome sequencing of replicate populations to determine the genetic changes responsible for a repeatable pattern of coevolution between bacteria and phage. I found that genetic changes conferring resistance in bacteria negatively impacted other traits such as growth rates and sensitivity to antibiotic. Different resistance mutations varied in the magnitude of their pleiotropic costs, and this resulted in a fixation bias favoring mutations that minimized pleiotropic effects. I manipulated the environment and found that differential pleiotropy between environments drove repeatable evolution at different genetic scales. Finally, I explored theoretically how bacteria, phage, and resource interact through a dynamic system of feedbacks. I used a mathematical model to describe priority effects in evolution, where the expected fate of a beneficial mutation varies depending upon whether it appears before or after a competing mutation. / 10000-01-01
688

Searching for sense in the library of Babel

Smith, Nick G. C. January 1999 (has links)
No description available.
689

The bivariate space density of galaxies

Cross, Nicholas James Geraint January 2002 (has links)
The luminosity function of galaxies, the measurement of the space density as a function of luminosity, is an important test of cosmology, galaxy formation and evolution. Unfortunately, there is a factor of two variation in recent measurements of the luminosity function. Most of this variation is due to systematic errors, caused by various selection effects. With two large new surveys, the Two degree Field Galaxy Redshift Survey and the Sloan Digital Sky Survey, underway it is important to recognise and eliminate these selection effects if we are going to improve our measurement of the luminosity function and fully utilise these surveys. By measuring the space density of galaxies as a function of surface brightness as well as luminosity, a bivariate brightness distribution, we can comprehend many of the selection effects such as light loss, incompleteness and the visibility of galaxies. Since galaxies have a variety of shapes and sizes, a distribution in luminosity and surface brightness helps to separate out different types of galaxy. Correlations between the luminosity and surface brightness place extra constraints on models of galaxy formation and evolution. When we analyse our results, we find that recent surveys that have not taken into account surface brightness selection effects underestimate the luminosity of the bright end by 5-10%. Using the bivariate brightness distribution, we can constrain the luminosity density to a range that varies by < 20% rather than by a factor of 2. We find that the luminosity function is flat over the range -19.5 < M < -17 and then rises sharply as late-type spiral galaxies begin to dominate. The space density does not vary with surface brightness with the result that low surface brightness galaxies are at least as common as normal galaxies. However, low surface brightness galaxies are also intrinsically faint, following the luminosity-surface brightness correlation for spirals, so they do not contribute significantly to the luminosity density.
690

Patterns of Variance and Covariance in Anthropoid Limb Proportions| Implications for Interpreting the Hominin Fossil Record

Powell, Vance C. R. 25 September 2018 (has links)
<p> Interpreting the taxonomic and behavioral implications of variation in the inferred limb proportions of fossil hominin taxa is contingent upon assessing how much variation exists in extant primate taxa and, by extension, how much of that variation is associated differences in their locomotor behaviors. However, the majority of evidence linking limb proportions to behavior in extant primates is based on taxonomically-restricted samples, or on species means as opposed to individual values, or does not account for field observations that capture the complexity of locomotor behavior in a primate taxon (see Napier &amp; Napier, 1967; Fleagle, 1988; see also Preuschoft, 2002). With regards to extinct taxa, the problem is compounded by a necessary reliance on relatively few associated skeletons, most of which are incomplete, or fragmented or both. </p><p> This thesis addresses the aforementioned issues using a) multivariate methods to quantify the relationships between limb proportions and behavioral repertoires in extant anthropoids; b) machine-learning methods to select relevant extant models with which to interpret the limb proportions of extinct taxa; and c) resampling methods to evaluate hypotheses regarding major adaptive shifts in inferred locomotor behavior.</p><p>

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