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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.
111

That Which Binds Us

Dover, Tracey M 01 June 2015 (has links)
This novel follows three individuals struggling with isolation and loneliness. Rina, a twenty-two year-old college student is studying abroad in Japan when she learns of her grandfather’s death. As his last living relative, she decides to leave her studies and a burgeoning romance to take care of her grandfather’s final affairs. At his funeral she meets Marcus, a mysterious man whose past ties in with her own. Marcus gives Rina the opportunity to uncover secrets surrounding her family and forces her to question not only her grandfather’s past but also her own identity. Tilnu is an immortal with a foggy memory of the past. He believes he is a fallen angel trying to reclaim his place in heaven by devoting his life to the hunting and killing of demons. After fighting a particularly powerful demon, he finds himself indebted to a young woman who guilts him into being her companion and prompts him to doubt his convictions about his own place in the world. Marcus, a demon able to live on Earth by making bonds to people, is caught between a rock and a hard place. After meeting Rina, he is unable to ignore his memories of past mistakes. With his time on Earth suddenly limited, and the persistent hunter Tilnu on his tail, he fears it may be too late to make up for his past sins against Rina and her family.
112

INTERNET USE AND SOCIAL ISOLATION: EXPLORING THE VARIABLES

Allen, Melissa Marie 01 June 2016 (has links)
Internet use is a growing trend in today’s society, and there are many variables surrounding use that can potentially affect individuals’ psychological well-being. The purpose of this study is to discover if the motivation for Internet use has a direct effect on individuals experiencing social isolation. An Explanatory Design was utilized for this study, and participants were comprised of 47 adult males and females. Quantitative data was collected for this study through use of online surveys, such as Internet use (observed motivation and frequency) survey, JongGierveld Loneliness Scale (explored emotional and social loneliness) and The Big 5 Personality Inventory (viewed personality traits). A significant finding of this study was that there was a positive relationship between individuals who are highly agreeable and the frequency of their Internet use. This study was unable to produce conclusive data on how motivation for Internet use influences episodes of social isolation. The results of this study do demonstrate the wide use of the Internet by adults, and reinforce the importance of incorporating this use in assessment and treatment of clients. Information obtained from this study also has potential to stimulate means of advocacy for protective Internet policies and formation of educational programs designed to highlight best practices for Internet use.
113

Chemical investigations of endophytic and fungicolous fungi

Kaur, Amninder 01 May 2013 (has links)
Fungi continue to serve as valuable sources of a diverse variety of bioactive secondary metabolites, some of which have found applications as important pharmaceuticals and agrochemicals. Our research group employs an ecology-based strategy for the selection of fungi for chemical studies. The research described here involves chemical investigation of fungicolous and endophytic fungi that resulted in the isolation and identification of many new natural products, as well as some previously known metabolites. Mycoparasitic and fungicolous fungi are those that colonize other fungi, and are viewed as potential sources of antifungal agents because of the negative effects exerted on their hosts due to this colonization. Many antifungal compounds have been isolated by members of our research group from such fungi. Fractionation of the ethyl acetate extracts of cultures of thirteen fungal isolates, followed by characterization using various NMR and MS techniques, afforded fifteen new and twenty-six known compounds representing diverse structural classes. Some of these compounds showed antifungal and antiinsectan effects accounting for bioactivities originally observed for the crude extracts. Endophytic fungi are those that inhabit host plants asymptomatically and may or may not cause disease after some time. Studies show that in some cases they may be beneficial to the host plant by providing protection against various pathogens or by improving the resistance of the host in some way. Such advantages may be due, at least in part, to the production of bioactive secondary metabolites by these fungi. Chemical investigations of seven crop endophytes led to the isolation and characterization of eleven new and twenty-eight known compounds. Some of these fungal known fungal metabolites exhibited antifungal, antimicrobial, and/or antiinsectan effects, and may therefore provide insight into the potential protective roles of the corresponding crop endophytes against plant pathogens or insect pests. The fungal secondary metabolites isolated during the course of these studies represent a variety of biosynthetic classes, including peptides, polyketides, terpenoids, and compounds with mixed biogenetic origins. Details of the isolation, structure elucidation, and biological activity of these new compounds are presented in this thesis. Structure elucidation was performed mainly by analysis of various MS and NMR data, although chemical derivatization reactions and/or X-ray diffraction analysis data were employed in some instances. Absolute configuration assignments were made using Mosher's method, X-ray crystallography, and/or by ECD spectral analysis in combination with computational analysis. Details of the isolation, structure elucidation, and biological activity of these new compounds are presented in this thesis.
114

Isolation and characterisation of P450 gene(s) in barley (Hordeum vulgare)

Nguyen, Linh Unknown Date (has links)
In plants, P450 enzymes encoded by P450 genes play a central role in numerous biosynthetic pathways, such as the production of secondary metabolites, stress responses and disease resistance. This thesis reports upon the utilization of molecular biology techniques to study P450 gene(s) in barley (Hordeum vulgare L.).Using several combinations of degenerate primers, a large number of barley P450 gene fragments were cloned and sequenced from two commercial varieties, Chebec and Harrington. Among 247 isolated sequences, twenty six percent were homologous to genes of known function. The abundance of these sequences differed between the two cultivars. Variations in the motif sequences of the cloned genes were also found between these two cultivars. In addition to the cloned fragments, twenty-two putative barley P450 encoding genes were identified from 24,000 cereal sequences in the International Triticeae EST Cooperative (ITEC) database by homology search. Among these Expressed Sequence Tag (EST) sequences, a full-length P450 sequence was selected for further investigation in this study.This novel P450 gene, CYP72A39, was expressed at a very early vegetative stage, but no expression was detected at the reproductive stage. Comparison of expression profiles of this gene and "digital expression" databases confirmed that this gene was homologous to several cereal EST clones with tissue-specific transcripts responding to various environmental stimuli, such as stresses and disease. Among these, many transcripts in barley were obtained from stressed tissues at the vegetative stage, and two transcripts in wheat (Triticum aestivum L.) were expressed after being challenged by barley powdery mildew pathogen (Blumeria graminis f. sp. hordei L.). This suggested that CYP72A39 may play a defence role in the barley seedling.The secondary structure of CYP72A39 was investigated in a comparative analysis using a computational approach. However, attempts to express CYP72A39 in a heterologous system and functional assays of the native protein in barley did not give decisive results, due to the disordered structure of the native protein and limitations of the current method. Screening the 3' UnTranslated Region (3'UTR) of this gene in 158 genotypes of domesticated, landrace and wild barley revealed two haplotypes, which differed by a 12 base indel positioned between two transversions. The presence of both haplotypes in wild and cultivated barley suggests this polymorphism predates the domestication of barley. This indel was mapped to the long arm of chromosome 6H, less than 10 centi-Morgans (cM) from the gene encoding resistance to powdery mildew in barley (B. graminis). A comparison between haplotype diversity and powdery mildew resistance data for over 102 genotypes showed a weak link between the 'long' haplotype and resistance, while the 'short' haplotype was associated with susceptibility. There was no evidence for a strong correlation between haplotype and quality type (malt or feed); however, more malting varieties had the long haplotype, suggesting a possible association with some attributes in modern malting barley. There was no evidence for association with other characteristics such as geographic origin, growth habit or row number. Phylogenetic relationship of the CYP72A39 to other CYP72 members was also investigated.
115

Serializable Isolation for Snapshot Databases

Cahill, Michael James January 2009 (has links)
PhD / Many popular database management systems implement a multiversion concurrency control algorithm called snapshot isolation rather than providing full serializability based on locking. There are well-known anomalies permitted by snapshot isolation that can lead to violations of data consistency by interleaving transactions that would maintain consistency if run serially. Until now, the only way to prevent these anomalies was to modify the applications by introducing explicit locking or artificial update conflicts, following careful analysis of conflicts between all pairs of transactions. This thesis describes a modification to the concurrency control algorithm of a database management system that automatically detects and prevents snapshot isolation anomalies at runtime for arbitrary applications, thus providing serializable isolation. The new algorithm preserves the properties that make snapshot isolation attractive, including that readers do not block writers and vice versa. An implementation of the algorithm in a relational database management system is described, along with a benchmark and performance study, showing that the throughput approaches that of snapshot isolation in most cases.
116

Subsurface conductive isolation of refraction correlative magnetic signals (SCIRCMS)

Erck, Eric Stephenson 15 November 2004 (has links)
Isolation of terrestrially-observed magnetic signals by restoring their diffusive loss due to subsurface electrical conductivity sufficiently correlates these signals with those derived from the Alfven ionospheric electron movement of refraction variation. Temporary magnetic observatories were established on a conductive sedimentary basin (with a sampling interval of 5 s) and on a resistive large igneous intrusion (with a sampling interval of 10 s). Conventional modeling techniques estimate and remove the effects of the magnetometer, geomagnetic diurnal changes, whorls (solar quiet current vortices), and some bays from the acquired signals. Conventional one-dimensional skin depth modeling estimates the diffusive attenuation. The residual magnetic signal and the diffusive filter (as applied to the topography) become quantities in the linear system estimation of the geoelectric subsurface. Angular frequency domain least squares solution of the equations yields an isolated magnetic anomaly spectrum. Interpretive refinement, by selection of the zero or near zero curvature onset of either the spectrum's real or imaginary component, critically prepares the signal solution for correlation to a pseudomagnetic anomaly signal. This is an independently-derived sequence of anomalous values derived from Global Positioning System (GPS) refracted ranges. Detailed application of the Biot-Savart law provides independent anomaly signals to which the magnetic anomalies correlations show great correlation improvement by the isolation. These correlation improvements are from 2% to 83% and 9% to 91% for the sedimentary basin and from 2% to 96% and 24% to 78% for the igneous intrusion.
117

Isolation and Purification of Anthocyanins from Black Bean Wastewater Using Macroporous Resins

Wang, Xiaoxi 01 May 2012 (has links)
Isolation and purification of anthocyanins from black bean canning wastewater by column chromatography with macroporous resins were investigated in this study. Different adsorption materials and adsorption conditions were compared and the most effective material and adsorption conditions were selected to purify anthocyanins. Purified anthocyanins then were identified by high performance liquid chromatography electrospray tandem mass spectrometry. The most effective macroporous resin was selected by comparing the adsorption performance of five different types of macroporous resins (Diaion Hp20, Sepabeads Sp70, Sepabeads Sp207, Sepabeads Sp700, and Sepabeads Sp710). Equilibrium adsorption isotherms of five resins with wastewater were measured and analyzed using Langmuir and Freundlich isotherm models. Both Langmuir and Freundlich models could describe the adsorption process. The adsorption and desorption behaviors of anthocyanins were studied using a dynamic method on the five types of resins, and Sp700 presented the highest adsorption capacity as well as desorption capacity, indicating that Sp700 is a good candidate for purification of anthocyanins from black bean canning wastewater. The most effective adsorption conditions were tested using Sp700. Dynamic adsorption and desorption were performed in glass columns packed with Sepabead Sp700 to optimize the purification process. Temperature during adsorption and desorption (25°C and 35°C) did not significantly affect the adsorption and desorption ratio. Adsorption ratio was significantly reduced when the flow rate increased from 1.5 mL/min to 2.5 mL/min. However, desorption ratio was not affected by flow rate (from 1.5mL/min to 0.3mL/min). Ethanol concentration (from 30% to 60%) did not affect desorption ratio. Four kinds of anthocyanins were identified in black bean canning wastewater. The major anthocyanins were delphinidin 3-glucoside, petunidin 3-glucoside, and maldvidin 3-glucoside, with a small amount of petunidin 3, 5-diglucoside also in the final product.
118

A Place Apart: The Harm of Solitary Confinement

Campbell, Alexandra 21 November 2012 (has links)
This thesis examines the world of solitary confinement within the prison system. My research was inspired by Ashley Smith, a 19-year old segregated inmate who died in isolation while seven guards watched. This outrageous occurrence prompted me to question the practice of solitary confinement and a prison system in which such an event could occur. Studying the history of solitary confinement left me surprised to learn that it was originally intended as a therapeutic and merciful alternative to the punishments of the day. This revelation was one of a series of inversions that led me to conclude that solitary confinement is a world apart, not just physically, but also socially, temporally and legally. I have concluded that improving the lives of those segregated within our prisons requires the world of solitary confinement to become anchored within the broader legal and social context.
119

A Place Apart: The Harm of Solitary Confinement

Campbell, Alexandra 21 November 2012 (has links)
This thesis examines the world of solitary confinement within the prison system. My research was inspired by Ashley Smith, a 19-year old segregated inmate who died in isolation while seven guards watched. This outrageous occurrence prompted me to question the practice of solitary confinement and a prison system in which such an event could occur. Studying the history of solitary confinement left me surprised to learn that it was originally intended as a therapeutic and merciful alternative to the punishments of the day. This revelation was one of a series of inversions that led me to conclude that solitary confinement is a world apart, not just physically, but also socially, temporally and legally. I have concluded that improving the lives of those segregated within our prisons requires the world of solitary confinement to become anchored within the broader legal and social context.
120

Measurement of the Inclusive Isolated Prompt Photon Production Cross Section at the Tevatron using the CDF Detector

Deluca Silberberg, Carolina 12 June 2009 (has links)
Esta tesis presenta la medida de la sección eficaz de producción de fotones inmediatos con |η|<1.0, pT > 30 GeV y asilamiento < 2 GeV usando 2.5 fb-1 de datos tomados por el detector CDF entre febrero de 2002 y agosto de 2007. La medida incluye 6 veces más datos que el último resultado publicado al momento de su realización, extendiendo el rango de pT cubierto por la misma en 100 GeV. La sección eficaz se mide para fotones de hasta 400 GeV, y testea las predicciones teóricas sobre 6 órdenes de magnitud, un orden de magnitud más que en resultados previos. La medida de la sección eficaz de fotones inmediatos ofrece una oportunidad única para poner a prueba las técnicas de indentificación de fotones en Física de Altas Energías. En esta tesis, presentamos una nueva técnica para suprimir el ruido de fondo irreducible que viene de los fotones producidos por la desintegracion de mesones. El método consiste en ajustar la variable de aislamiento energetico del fotón en el calorímetro a la suma de las formas esperadas (templates) para esta variable para la señal y para el ruido de fondo, en diferentes rangos en el momento transverso del fotón. El método de las templates es simple y está basado únicamente en información del calorímetro. Además, reduce significativamente el error sistemático asociado con la pureza de los fotones. En medidas previas durante el Run I de CDF se emplearon técnicas basadas en la información de los detectores CES y CPR, resultando en errores sistemáticos y estadísticos de considerable magnitud. Con el método introducido en esta tesis, el error sistemático en la pureza de los fotones se reduce desde el 30% de las medidas previas durante el Run I, a un 5% a alto pT de los fotones. Con la mejora de las simulaciones de Monte Carlo, el método de las templates tiene el potencial de convertirse en una poderosa herramienta para futuras búsquedas de nueva física usando estados finales con fotones. En esta medida, los datos se comparan con predicciones teóricas dadas por JETPHOX, con CTEQ6.1M PDF, funciones de fragmentación BFGII, y las escalas de renormalización, fragmentación y factorización fijadas para igualar el momento transverso del fotón. Los datos se corrigen por efectos de acceptancia y de resolución del detector, así como por ineficiencias en el proceso de identificación de los fotones, usando muestras simuladas de fotones inclusivos con PYTHIA. Este procedimento se denomina unfolding. Los factores derivados del unfolding no presentan una dependencia fuerte con el pT del fotón, y varían entre un 64% y un 69% en todo el rango de pT considerado. Las predicciones teóricas están corregidas para tener en cuenta los efectos no perturbativos, no considerados inicialmente en los cálculos teóricos. Los errores sistemáticos en la medida son el orden del 13% a bajo pT, dominados por las incertidumbres en la determinación de la fracción de fotones reales, mientras a alto pT son del orden de un 15%, mayormente debidos a la incertidumbre en la escala de energías del fotón. Las incertidumbres en la teoría son debidas a la incertidumbre en las PDF, de un 5% bajo pT, pero que se incrementa hasta llegar a un 15% a alto pT. La dependencia en las predicciones debido a la particular elección en las escalas es de un 15% a bajo pT, decreciendo hasta un 8% a alto pT. Los resultados muestran que la teoría describe bien los datos para fotones por encima de 40 GeV. En el rango hasta 150 GeV, la producción de fotones inmediatos está dominada por el proceso Compton de QCD, mientras que para pT más altos los gluones contribuyen substancialmente a la sección eficaz, y la medida es útil para imponer límites en las PDF de los gluones. Para pT < 40 GeV los datos están por encima de las predicciones, reproduciendo las tendencias ya observadas anteriormente en otras medidas, tanto en colisionadores como en experimentos de blanco fijo. Ésta es por tanto, probablemente debida no sólo a los efectos sistemáticos en la técnica experimental empleada, sino que encierran efectos físicos que no han sido tenidos en cuenta en los cálculos teóricos. La comparación de los datos con predicciones obtenidas usando la parametrización MRST04 para las PDF resulta en resultados similares, tanto en forma como en magnitud, a los obtenidos con CTEQ6.1M. El cuociente data sobre teoría tiene un comportamiento similar en ambos para fotones de bajo pT, aunque en la totalidad del rango considerado ambas tienen una pendiente ligeramente distinta. La medida está aprobada por la Colaboración de CDF y se ha mostrado en numerosas conferencias internacionales. Los resultados han sido publicados en Physics Review D. / This thesis presents the measurement of the inclusive photon cross section for photons with |!|<1.0, pT > 30 GeV and isolation < 2 GeV using 2.5 fb-1 of data taken by the CDF detector between February 2002 and August 2007. This measurement includes 6 times more data than the last published result, extending its pT coverage by 100 GeV. The cross section is measured up to 400 GeV, and tests the theoretical predictions over 6 orders of magnitude, one order of magnitude more than in previous results. The prompt photon cross section measurement offers a unique opportunity to test the photon identification variables over a large energy range. In this thesis we present a new technique to suppress the irreducible isolated photons from meson decays. The method consists of fitting the calorimeter isolation distribution in the data to pure signal and background templates for every bin in the photon pT. The template method is simple and is based only on the information from the calorimeter. Moreover, it significantly reduces the systematic uncertainty associated to the photon purity. Previous CDF Run I measurements used techniques based on the information collected by the CES and the CPR detectors, which have considerable statistical dilution and systematics. With the method introduced in this thesis, the systematic uncertainty in the photon purity is reduced from 30% in the previous CDF Run I measurements to 5% at high pT. With the improvement of the Monte Carlo simulations, the template method has the potential to become a powerful tool for future searches using photon signatures. In this measurement, the data are compared to theoretical predictions given by JETPHOX using CTEQ6.1M PDF, BFGII fragmentation functions, and renormalization, fragmentation and factorization scales set to equal the transverse momentum of the photon. Data are unfolded back to hadron level to correct for efficiencies and detector acceptance and resolution using a bib-by-bin unfolding procedure implemented in a PYTHIA inclusive photon Monte Carlo sample. The unfolding factors do not present a strong dependence on the photon pT, and vary between 64% and 69% in the range considered. The theoretical predictions are corrected for non-perturbative QCD effects. The systematic uncertainties in the measurement are of 13% at low pT, dominated by the signal fractions, while at high pT they are of about 15%, mainly coming from the photon energy scale. The uncertainties in the theory are due to the PDF, of around 5% at low pT and increasing to 15% at high pT. The dependence left in the prediction due to the choice of the scales is of 15% ay low pT and decreases to around 8% at high pT. We find agreement between data and theory above 40 GeV. In the pT range until 150 GeV, the prompt photon production is dominated by the QCD Compton process, while for higher pT gluons substantially contribute to the prompt photon production, though they are not the dominant source, and the measurement is useful to constrain the gluon PDF. For pT < 40 GeV the data falls above the theory, reproducing a trend already seen in previous measurements, both in colliders and fixed-target experiments, and it is probably not only due to systematic effects in the experimental method but more likely to other physics effects that are not accounted for in the theoretical calculations. The comparison to the predictions obtained using the MRST04 parameterization for the PDF is in agreement with the results obtained with CTEQ6.1M for the whole measured range. The ratio data over theory has a similar shape for both for low pT photons, though in the whole pT range the ratio presents a slightly different slope. The measurement is approved by the CDF Collaboration and has been shown in a large number of international conferences. The results have been also published as a rapid communication in Physics Review D.

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