• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 190
  • 55
  • 42
  • 41
  • 35
  • 30
  • 18
  • 7
  • 6
  • 4
  • 4
  • 4
  • 3
  • 2
  • 2
  • Tagged with
  • 514
  • 54
  • 34
  • 33
  • 33
  • 32
  • 32
  • 29
  • 28
  • 26
  • 25
  • 23
  • 22
  • 21
  • 21
  • 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.
1

Characterization of the Neurospora Varkud Satellite Plasmid and Transcript in vivo

Keeping, Andrew 10 January 2012 (has links)
The Varkud satellite (VS) plasmid is found in the mitochondria of some strains of Neurospora, and exhibits properties that may allow it to be developed as a genetic transformation vector to study mitochondrial molecular biology. An ideal transformation vector would not confer a phenotype. The overall goal of my thesis was to examine interactions of VS with its Neurospora host to identify possible phenotypes, using biochemical and proteomic approaches. Biochemical experiments provided evidence consistent with the plasmid transcript, VS RNA, being present as a ribonucleoprotein particle that can be separated from ribosomal subunits by sucrose density gradient centrifugation; however, no VS-specific proteins were identified under the purification conditions examined. During the analyses of proteomic data I obtained new insights into the consequences of the statistical methods commonly used to normalize quantitative 2D gel data. However, irrespective of the method used, the fraction of the proteome amenable to 2D gel-based proteomics revealed, at most, subtle effects of VS on the abundance of a few proteins. I also observed no differences in growth rate between strains differing by the presence or absence of VS when grown in the presence of inhibitors and stressors affecting a wide range of mitochondrial and other cellular functions. Overall, despite VS RNA being as abundant as the large and small mitochondrial ribosomal RNAs, my genetic, biochemical and proteomic investigations of the effect of VS on its host strain provides evidence that VS is a phenotypically neutral element.
2

Characterization of the Neurospora Varkud Satellite Plasmid and Transcript in vivo

Keeping, Andrew 10 January 2012 (has links)
The Varkud satellite (VS) plasmid is found in the mitochondria of some strains of Neurospora, and exhibits properties that may allow it to be developed as a genetic transformation vector to study mitochondrial molecular biology. An ideal transformation vector would not confer a phenotype. The overall goal of my thesis was to examine interactions of VS with its Neurospora host to identify possible phenotypes, using biochemical and proteomic approaches. Biochemical experiments provided evidence consistent with the plasmid transcript, VS RNA, being present as a ribonucleoprotein particle that can be separated from ribosomal subunits by sucrose density gradient centrifugation; however, no VS-specific proteins were identified under the purification conditions examined. During the analyses of proteomic data I obtained new insights into the consequences of the statistical methods commonly used to normalize quantitative 2D gel data. However, irrespective of the method used, the fraction of the proteome amenable to 2D gel-based proteomics revealed, at most, subtle effects of VS on the abundance of a few proteins. I also observed no differences in growth rate between strains differing by the presence or absence of VS when grown in the presence of inhibitors and stressors affecting a wide range of mitochondrial and other cellular functions. Overall, despite VS RNA being as abundant as the large and small mitochondrial ribosomal RNAs, my genetic, biochemical and proteomic investigations of the effect of VS on its host strain provides evidence that VS is a phenotypically neutral element.
3

HIV Care Continuum among Subpopulations of MSM, Georgia, 2012

Gleske, Hilary 09 January 2015 (has links)
Background: As of 2012, Georgia ranked fifth in the United States in the number of people diagnosed with HIV/AIDS. Given the high burden of disease among men who have sex with men (MSM), the HIV Care Continuum has become an important measure for keeping persons living with HIV in care and eventually reaching an undetectable viral load. Methods: Data were extracted from the Enhance HIV/AIDS Reporting System (eHARS) using SAS version 9.3.A univariate analysis was then performed by cross tabulating variables such as linked to care, any care in 2012, retained in care and viral suppression (VS) for men who have sex with men only (MSMO) and men who have sex with men and women (MSMW), stratified by race/ethnicity and age. Results: Among 20,676 males categorized as MSM, 14,316 (69%) were MSMO and 6,360 (31%) were MSMW. Among MSMO, 77% (N=772) were linked to care and 45% were virally suppressed and among MSMW, 75% (N=219) were linked to care and 40% were virally suppressed. Black men have the lowest percentages along the HIV Care Continuum when compared to other race/ethnicities of MSMO and Hispanic/Latino MSMW have the lowest linkage to care of any race/ethnicity for both subpopulations. In both MSMO and MSMW, linkage, any care, retention, and VS increase with increasing age. Conclusion: MSM suffer are terribly affected by HIV and a substantial proportion of MSM also engage in sexual contact with women, who may not be aware of their partner’s HIV risk status. Much speculation can be drawn about what keeps both MSMO and MSMW from being linked to care or reaching an undetectable viral load. Possibilities may include greater perception of stigma, ambivalence about HIV care and increased denial affecting ART adherence for MSMW as compared to MSMO. In order to see a drop in HIV rates within this group, the outside factors that negatively influence a person’s progress along the HIV Care Continuum toward an undetectable viral load must be understood and addressed.
4

Information and politics /

Frisell, Lars, January 1900 (has links)
Diss. Stockholm : Handelshögsk., 2001.
5

Leukaemic relapse after allogeneic haematopoietic stem cell transplantation and the use of the graft-versus-leukaemia effect /

Carlens, Stefan, January 1900 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 6 uppsatser.
6

A control theoretic perspective on learning in robotics

O'Flaherty, Rowland Wilde 27 May 2016 (has links)
For robotic systems to continue to move towards ubiquity, robots need to be more autonomous. More autonomy dictates that robots need to be able to make better decisions. Control theory and machine learning are fields of robotics that focus on the decision making process. However, each of these fields implements decision making at different levels of abstraction and at different time scales. Control theory defines low-level decisions at high rates, while machine learning defines high-level decision at low rates. The objective of this research is to integrate tools from both machine leaning and control theory to solve higher dimensional, complex problems, and to optimize the decision making process. Throughout this research, multiple algorithms were created that use concepts from both control theory and machine learning, which provide new tools for robots to make better decisions. One algorithm enables a robot to learn how to optimally explore an unknown space, and autonomously decide when to explore for new information or exploit its current information. Another algorithm enables a robot to learn how to locomote with complex dynamics. These algorithms are evaluated both in simulation and on real robots. The results and analysis of these experiments are presented, which demonstrate the utility of the algorithms introduced in this work. Additionally, a new notion of “learnability” is introduced to define and determine when a given dynamical system has the ability to gain knowledge to optimize a given objective function.
7

Red Dresses for Funerals

Brooks, Michelle Marie 05 1900 (has links)
Red Dresses for Funerals contains a scholarly preface concerning the nature of factuality versus credibility in the writing of fiction. Four original short stories are included in this thesis. "A Night With Lawrence Welk" explores the relationship between a patient and student intern psychologist. "Red Dresses for Funerals" is about a wedding that plays a significant role in a variety of the characters' lives. "Trace Elements" is the only story involving young children. "Trace Elements" explores the beginning of understanding of some of the grimmer aspects of reality. "Expectations, Great and Otherwise" addresses the issue of denial. These stories are linked by their setting, a small town in Texas.
8

Two types of focus in Castilian Spanish

Chung, Hye-Yoon 15 February 2013 (has links)
This dissertation proposes an experimental study of focus in Spanish, investigating, in particular, if two types of focus – Contrastive focus and Non-contrastive focus – are syntactically and prosodically distinguished. The evidence that the conceptual distinction between the focus subtypes can be represented linguistically has been found in languages (Drubig 2003, É. Kiss 1998, Gundel & Fretheim 2001, Zubizarreta 1998 to name a few). As for Spanish, Zubizarreta (1998) argued that the two types of focus most noticeably differ syntactically. While Non-contrastive Focus should appear at utterance-final position, Contrastive Focus may appear in-situ. Nevertheless, not all the studies seem to accept Zubizarreta’s (1998) syntax-oriented distinction between the two focus types. A few studies suggest that not only Contrastive Focus but also Non-Contrastive Focus can indeed occur sentence-internally (Cabrera Abreu & García Lecumberri 2003, Kim & Avelino 2003, Toledo 1989). Inspired by a handful of studies and motivated by empirical data gathered for the pilot study, the current study sets out to investigate Zubizarreta’s (1998) syntax-oriented claim on the distinction between the focus subtypes. Focus in Spanish is known to be prosodically marked by its particular intonational contour- higher pitch and the early peak, and secondarily longer duration and/or higher intensity, compared to unfocused elements in a given utterance (Cabrera Abreu & García Lecumberri 2003, Domínguez 2004a & b, Face 2000, 2001, 2002b, Hualde 2003, 2005, Kim & Avelino 2003, de la Mota 1995, 1997, Navarro Tomás 1918, Nibert 2000, Quilis 1971, Sosa 1998, Toledo 1989, Zubizarreta 1998). We assume that the distinction between the two types of focus would also be made using the existing cues, as suggested by a handful of studies on focus types (Cabrera Abreu & García Lecumberri 2003, Kim & Avelino 2003, Zubizarreta, 1998). The findings of our experiments clearly indicate that Spanish speakers consistently use different phonetic and phonological cues such as duration and pitch in order to make a distinction between the two types of focus. These findings give clear evidence that the pragmatically defined notion of focus (Lambrecht 1994) is indeed further divided into two types in Castilian Spanish, somewhat similar to the distinction made in English (Selkirk 1984, 1995). / text
9

Field studies comparing SASW, beamforming and MASW test methods and characterization of geotechnical materials based on Vs

Yuan, Jiabei 13 October 2011 (has links)
Estimating S-wave velocities (Vs) from Rayleigh-wave velocities (VR) is widely used in field seismic testing for geotechnical engineering purposes. In this research, two widely used surface-wave methods, the Spectral-Analysis-of-Surface-Waves (SASW) and Multichannel-Analysis-of-Surface-Waves (MASW) methods, are evaluated and compared in field experiments. An experimental parametric study was undertaken of the SASW and MASW methods. Conventional seismic sources in the SASW method are sledge hammers, bulldozers and vibroseises. For MASW testing, sledge hammers and small shakers are usually used as the seismic sources. In this research, MASW testing was performed with traditional and non-traditional sources at a site owned by the City of Austin, Texas. Experimental dispersion curves and Vs profiles from SASW tests are used as references for the field parametric study with the MASW method. The source type, source offset, receiver spacing and number of receivers were varied to evaluate the impact of each variable on the field experimental dispersion curve. Two type of receivers, 1-Hz and 4.5-Hz natural-frequency geophones, were also compared in these tests. A second part of this research involved studying the use of characterizing geotechnical materials based on Vs. This work included two projects. The first project involved basalt on the Big Island of Hawaii. To develop empirical ground motion prediction models for the purpose of earthquake hazard mitigation and seismic design on the Big Island, the subsurface site conditions beneath 22 strong motion stations were investigated by SASW tests. Vs profiling was performed to depths of more than 100 ft. Vs30, the average Vs in the top 30 m, was also calculated to assign NEHRP site classes to different testing locations. Different materials, mainly thought to be stiff basalt, were characterized and grouped based on the Vs values. These groups were then compared with reference curves for sand and gravel (Menq, 2003) to differentiate the groups. The second project dealing with charactering geotechnical materials based on Vs involved of soil/rock profiles at a project site in British Columbia, Canada. The goals in terms of this research were to: (1) compare the Vs profiles from the different test locations to investigate the stiffnesses of different geologic materials, the variability in the material stiffnesses, and the estimated depth to bedrock, and (2) to compare the Vs profiles to existing geological and geotechnical information such as nearby boreholes, cone penetration tests and seismic cone penetration tests. Good agreement between SASW Vs profiles and boring records is expected when lateral variability at the site is low. However, when lateral variability is significant, then the difference between localized measurements, like borings and CPT results, and global measurements, like SASW Vs results, can further contribute to understanding the site conditions as shown at the site in British Columbia, Canada. / text
10

Ceramide-mediated platform generation regulates apoptosis in vitro and in vivo /

Rotolo, Jimmy A.. January 2007 (has links)
Thesis (Ph. D.)--Cornell University, May, 2007. / Vita. Includes bibliographical references (leaves 134-143).

Page generated in 0.0292 seconds