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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.
311

Patterns of Genome Size in the Copepoda

Wyngaard, G. A., Rasch, E. M. 01 January 2000 (has links)
Adult somatic nuclear DNA contents are reported for eleven cyclopoid species (Megacyclops latipes, Mesocyclops edax, M. longisetus, M. ruttneri, M. leuckarti, M. woutersi, Macrocyclops albidus, Cyclops strenuus, Acanthocyclops robustus, Diothona oculata, Thermocyclops crassus) and for the harpacticoid Tigriopus californicus and range from 0.50 to 4.1 pg DNA per nucleus. These diploid genome sizes are consistent with previously published values for four Cyclops species (0.28-1.8 pg DNA per nucleus), but are strikingly smaller than those reported for marine calanoids (4.32-24.92 pg DNA per nucleus). We discuss three explanations, none of them exclusive of another, to account for the smaller size and range of cyclopoid genome sizes relative to calanoid genome sizes: (1) higher prevalence of chromatin diminution in the Cyclopoida, (2) phylogenetic structure or older age of the Calanoida relative to Cyclopoida and (3) nucleotypic selection that may influence life history variation and fitness. Measurements of genome size were made on Feulgen stained, somatic cell nuclei, using scanning microdensitometry which is well suited to the sparse and heterogeneous populations of copepod nuclei. The importance of measuring large numbers of nuclei per specimen, possible sources of variation associated with cytophotometric measurements, and appropriate use of internal reference standards and stoichiometry of the Feulgen stained nuclei are discussed.
312

Optical Parametric Amplification: from Nonlinear Interferometry to Black Holes

Florez Gutierrez, Jefferson 29 March 2022 (has links)
We explore the optical parametric amplifier, an optical device where a pump field creates a pair of lower-frequency fields: signal and idler. The pump field is usually treated classically, but this thesis focuses on scenarios where the pump must be treated quantum mechanically. One of these scenarios is the growing field of nonlinear interferometry, where the fundamental sensitivity of a probed relative phase can beat the classical bounds and reach the maximum limit allowed by quantum mechanics, the Heisenberg limit. Indeed, we show that a fully quantum nonlinear interferometer displays a Heisenberg scaling in terms of the mean number of input pump photons. This result goes beyond the well-accepted Heisenberg scaling with respect to the down-converted photons inside the interferometer, which predicts unphysical phase sensitivities starting at a particular input pump energy. Our theoretical findings are particularly useful when designing a nonlinear interferometer with bright pump fields or optimized optical parametric amplifiers for quantum metrology and quantum imaging applications. The quantum nature of the pump field may also play a central role concerning other physical phenomena, like Hawking radiation in the context of black holes. As suggested by several authors, both the optical parametric amplifier and Hawking radiation comprise the creation of fundamental particle pairs. Thus, if the optical parametric amplifier is fully treated quantum mechanically, we may get insight into an open problem in modern physics, namely the black hole information paradox. According to this paradox, the information stored in a black hole can be destroyed once the black hole has evaporated by emitting Hawking radiation, contradicting quantum mechanics. Despite the experimental efforts to build systems that reproduce event horizons and gravitational effects in the laboratory, the evaporation of black holes due to the emission of Hawking radiation remains a challenging task. In this thesis, we experimentally investigate the impact of an evolving pump field in an optical parametric amplifier by optimizing a parametric down-conversion process. We measure the pump and signal photon number properties, finding that the pump field gets chaotic and the signal coherent when the pump displays some sizeable depletion. We arrive at similar conclusions about the pump field from its measured Wigner function. Our experiment is the first step towards a successful experiment that could suggest that information in the black hole is not destroyed but encoded in the emitted Hawking radiation starting at some point in the black hole evolution. We finally discuss further experimental improvements to investigate the parallel between the optical parametric amplifier and Hawking radiation.
313

LIMTRÄBALKAR SOM SUBSTITUT FÖR BETONG : En undersökning av limträbalkars substitutionseffekter sett till CO2 i atmosfären. / GLULAM BEAMS AS SUBSTITUTE FOR CONCRETE : A survey on the substitution effects of glulam beams in relation to carbondioxide in the atmosphere.

Brännlund, Alexina January 2020 (has links)
Today, a lot of resources are put into researching technological solutions concerning “carbon neutral” displacement materials and products, with the common goal of mitigating the amount of carbon dioxide in the atmosphere. The aim of this study was to find out whether a displacement of concrete to glulam beams, in the construction industry, could create substitution effects that reduces the amount of carbon dioxide in the atmosphere. To go about this, interviews were conducted with one producer of glulam beams, four construction companies and a non-profit foundation that funds research in fire prevention. Furthermore, sustainability declarations of glulam beams from three glulam beam producers, were analyzed. To compare carbon dioxide emissions in different scenarios, the interview results, as well as the sustainability declarations of the glulam beam producers, were compared and examined. Calculations of carbon dioxide sequestered in glulam beams and emitted from the concrete industry in Sweden were also regarded. The results showed that the possible substitution effects derived from a displacement of concrete to glulam beams, would have a small mitigating impact on the amount of CO2 in the atmosphere. However, recent findings point out that the pay back period for harvested trees, is longer than assumed. Moreover, the concrete production is not decreasing, but increasing. In respect of Jevons’ paradox (which concludes that higher efficiency in production leads to more consumption, not less), the conclusion of this study, was that no substitution will mitigate enough CO2 in the atmosphere. Our approach to consumption is what must change.
314

Preconception Health and Preterm Birth Differences Among U.S.-Born and Foreign-Born Black Women

Keitt, Sheree Holmes 01 January 2019 (has links)
Foreign-born Black women giving birth in the United States have superior preterm birth outcomes compared to their U.S-born Black peers. Many studies have focused on tobacco use and medical risk factors, but few have focused solely on preconception health. The purpose of this study was to examine preconception health and preterm birth differences among U.S.-born and foreign-born Black women. Three theoretical frameworks guided this study: the life course theory, healthy migrant theory/immigrant paradox, and weathering theory. Primary research questions assessed (a) if there were an association between chronic preconception risk factors, prepregnancy obesity, diabetes, and hypertension, in U.S.-born and foreign-born Black women, (b) if U.S.-born Black women had a higher risk of having a preterm infant compared to foreign-born Black women, and (c) if weathering existed in U.S.-born and foreign-born Black women. A quantitative design using the 2017 Natality Public Use File was employed that included non-Hispanic Black women ages 15 to 44 years. Chi-square test and binary logistic regression were used for the data analysis. Key findings revealed (a) a statistically significant association between preterm birth and chronic preconception health risk factors in both groups of women, (b) U.S.-born women were roughly 1.4 times more likely to have a preterm infant than foreign-born women, and (c) both groups experienced weathering. This study might positively impact social change by offering an alternative perspective to the reproductive health advantage of foreign-born Black women. This perspective can aid in advancing policy and systems change strategies to address the root causes of racial and ethnic disparities in birth outcomes, advance health equity, and improve maternal health.
315

Metaphorical Interpretations of the Neurotic Paradox

Weaver, Mark J. 01 May 1981 (has links)
This is a theoretical/philosophical paper which is intended to bring to the reader's attention an emerging literature and discussion which holds potentially productive consequences for the understanding of man. This thesis does not offer completed formulations or empirical groundings. The purpose is to create a basis for dialogue. This paper will initially specify a current conflict in psychology around the different metaphors used to define the image of man. A theoretical/philosophical basis for viewing the process of generating models of man and his behavior as essentially "metaphorical" is then presented. A specific category of human behavior known as the neurotic paradox (henceforth abbreviated NP) is defined and a review of literature on the root metaphorical interpretations of the NP is discussed. The prominent extant models of human behavior reviewed in this discussion are those based on the metaphors Spirit, Disease, Machine, and Seed. The limitations of each model will be discussed with regard to that model's adequacy to provide understanding of the four basic defining characteristics of the NP. This section constitutes the main body of the thesis. This evaluative discussion of the theoretical/philosophical inadequacies of each model is intended to bring to light the process and strategies (both explicit and implicit) which have evolved in the interpretation of the image of man.
316

Self-Reliance, Social Welfare, and Sacred Landscapes: Mormon Agricultural Spaces and Their Paradoxical Sense of Place

Garner, Anthony Ross 01 August 2018 (has links)
What is the sense of place of Mormon agricultural landscapes? That is to say, what makes an LDS Church-owned welfare farm or a Mormon family garden meaningful to those who interact with it? In formulating a partial answer to this question, this thesis demonstrates how religious ideals of self-reliance and social welfare explicitly define Mormon agricultural landscapes, providing a sacred sense of their purpose to those who work and benefit from them. However, these sacred landscapes are complicated by developments of industrial agricultural equipment, corporate institutions, and urban demographics, which tend to isolate people from each other and the land they live from while developing in them a false sense of independence and sustainability. The LDS Church and its membership have learned to mitigate these negative implications to a degree, though I suggest doctrinal reasons they could do better. As case studies, this thesis examines the motives and methods of an industrially scaled Church welfare farm in Blue Creek, Utah and a Mormon family garden in Bluffdale, Utah. Contextualized within relevant American and Mormon history, I explore the paradoxical sense of place of Mormon agricultural landscapes where ideals of self-reliance and social welfare thrive and social isolation and emotional interconnection coexist, which makes room for principles of economic efficiency and environmental conservation to find a compromise.
317

The Other means? Examining the patterns and dynamics of state competition in cyberspace

Vicic, Jelena January 2021 (has links)
No description available.
318

MEZIPROSTOR (MORFOLOGIE NEVIDĚNÉHO) / INTERSPACE (MORFOLOGY OF UNSEEN)

Stehlíková, Iveta January 2017 (has links)
The main idea of my diploma work is the view into the invisible world of microscopic objects. Their forms and structures are not used as such, but they are taken out from them and new forms are created from them. With a exaggeration absurdity and illustrating, I create new dimensions of the world that can not be seen by the eye or the device. Using the combination of spatial and also flat painting, I point to the paradox of the existence of space as the human being perceived it.
319

Grasping At Freedom: Identity, Paradox, and Concessions of Will in the Works of Conrad, Gide, and Woolf

Dillenberger, Susanna Juliana 04 September 2019 (has links)
No description available.
320

“`Mine honor is my life’: An Examination of William Shakespeare’s Portrayal of the Connection Between Life and Honor”

Wagler, Madeleine S. 23 April 2021 (has links)
No description available.

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