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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.
591

XML schemų sudarymo ir normalizavimo metodika / Design and Normalization Methodology for XML Schema

Vyšniauskaitė, Ramutė 25 May 2005 (has links)
In this work analyses the transition from UML class diagrams to XML schema. The main problems, such as - UML does not include all the features required to describe a XML schema - are explored. Also, the principles of XML schema normalization, resemblances and differences between applying normal forms to XML documents and relational data bases are presented.
592

Formulių redukcija multiplikatyvioje aritmetikoje / Reduction Of Formulas In The Multiplicative Arithmetic

Aleksandrovič, Alesia 16 August 2007 (has links)
Magistriniame darbe ,,Formulių redukcija multiplikatyvioje aritmetikoje” nagrinėjamas sekvencinis multiplikatyvios aritmetikos variantas su lygybe. Šis skaičiavimas yra bazė, kuriant skaičiavimus,naudojamus automatizuojant įrodymus įvairiuose aritmetikos fragmentuose. Darbo tikslas- susipažinti su įrodymo teorija bei jos taikymu sekvenciniame multiplikatyviosios aritmetikos variante.Darbas padalintas į 3 skyrius : pargindinės sąvokos, pagalbinės lemos ir formulių redukcija. Pradžioje pateikiamas trumpas įvadas į Peano aritmetiką.Apibrėžiamas sekvencinis skaičiavimas K, turintis neloginių simbolių signatūrą {0,',P, *,=}.Savarankišką darbo dalį sudaro antrasis bei trečiasis skyriai.Bet kuriai bekvantorinei skaičiavimo K formulei A(x) randama tam tikros formos jai ekvivalenti normalioji disjunkcinė forma.Taip pat nagrinėjama sutvarkytųjų formulių redukcija. / In this postgraduate work “Reduction of formulas in the multiplicative arithmetic” the sequential variant with equality of multiplicative arithmetic is being analyzed. This calculus is a base when creating calculations which are used in different fragments of arithmetic. The aim of this work is to get acquainted with a proving theory and its application in sequential variant of multiplicative arithmetic. The work is divided into 3 sections: main conceptions, auxiliary lemmas and formula’s reduction. The short introduction into Pean’s arithmetic is given in the beginning. The sequential calculus K, which has non-logical symbol’s signature {0,`,P,.,=} is being described. Sections 2 and 3 are self-sufficient parts of this work. For any formula A(x) of calculation K the equivalent normal disjunctive form is found. Also the reduction of ordered formulas is analyzed.
593

Long time behavior of stochastic hard ball systems

Cattiaux, Patrick, Fradon, Myriam, Kulik, Alexei M., Roelly, Sylvie January 2013 (has links)
We study the long time behavior of a system of two or three Brownian hard balls living in the Euclidean space of dimension at least two, submitted to a mutual attraction and to elastic collisions.
594

Prevalence and characterization of Gardnerella vaginalis in pregnant mothers with a history of preterm delivery

Stemmet, Megan January 2012 (has links)
<p>Risk factors such as intrauterine and vaginal infection put pregnant women at risk for delivering preterm. Bacterial vaginosis (BV) is a polymicrobial clinical syndrome commonly diagnosed in women of reproductive age, with women of African descent with low socioeconomic status and previous preterm delivery at high risk. Although frequently isolated from healthy women,&nbsp / Gardnerella vaginalis has been most frequently associated with BV. There is limited data available on the prevalence of BV in Southern Africa / therefore, we embarked on a study to determine the&nbsp / prevalence of BV and G. vaginalis in predominantly black communities in the Western Cape, in order to establish the role of G. vaginalis in BV. Women attending various Maternity and Obstetrics&nbsp / units (MOU) in the Cape Peninsula with and without a history of pre-term delivery (PTD) were invited to participate in the study. Several factors were statistically associated with pregnancy history,&nbsp / including location of study population, parity, smoking and presence of clinical symptoms. The presence of G. vaginalis was determined by culture in 51.7% of the preterm delivery group (PTDG)&nbsp / and 44% of the full-term delivery group (FTDG) women. BV was detected in 31.13% of PTDG and 23.67% of FTDG by Gram stained analysis according to Nugent scoring criteria, with age and HIV&nbsp / status posing as risk factors. When comparing PTDG and FTDG for an association between the presence of G. vaginalis and BV, a stronger association was observed in the PTDG but it was not statistically significant. In both PTDG and FTDG, G. vaginalis was isolated significantly more often in women diagnosed with BV at 24.5% (p &lt / 0.05). Antibiogram studies revealed both Metronidazole and Clindamycin resistant strains of G. vaginalis. G. vaginalis Biotype 7 is specifically associated with BV, while Biotype 2 appears to be associated with BV in women with a history&nbsp / of PTD. Accuracy of diagnostic tools were tested and it was determined that Nugent scoring is more sensitive in diagnosing BV (76.04%), but culture for G. vaginalis is more specific (83.21%). Although this study was limited in that we were unable to follow-up pregnancy outcomes, we were able to confirm the perceived role of G. vaginalis in BV.&nbsp / </p>
595

Molecular Dynamics of the RNA Binding Cavity of Influenza A Non-structural Protein 1 (NS1) RNA Binding Domain

Whittington, Christi Leigh 01 January 2012 (has links)
Molecular dynamics simulations were performed on the influenza A non-structural protein 1 (NS1) RNA binding domain (RBD), a homodimer. Fourteen simulations were performed at 298K, nine ionized with 0.1M KCl and five with no ions. Several analysis techniques were employed to study RBD residue flexibility. The focus of the study was the RNA binding cavity formed by side chains of helix 2 (chain A) and helix 2’ (chain B) and cavity intermonomeric salt bridges. Opening of the salt bridges D29–R46’ and D29’–R46 was observed in several of the trajectories. The RNA binding cavity has large flexibility, where the dimension and shape change during the dynamics. One pair of residues surrounding the cavity and necessary for RNA binding, residues R38 and R38’, have motions during the simulations which cover the top of the cavity. There is correlation between the salt bridge breaking, flexibility of R38 and R38’, and the cavity size and shape changes. Possible RBD small molecule drug targets are these two salt bridges and the pair R38 and R38’. Disrupting the events that occur around these areas could possibly inactivate RNA binding function of the domain. These results could have implications in searching for potential molecules that effectively treat influenza A.
596

Topics on Regularization of Parameters in Multivariate Linear Regression

Chen, Lianfu 2011 December 1900 (has links)
My dissertation mainly focuses on the regularization of parameters in the multivariate linear regression under different assumptions on the distribution of the errors. It consists of two topics where we develop iterative procedures to construct sparse estimators for both the regression coefficient and scale matrices simultaneously, and a third topic where we develop a method for testing if the skewness parameter in the skew-normal distribution is parallel to one of the eigenvectors of the scale matrix. In the first project, we propose a robust procedure for constructing a sparse estimator of a multivariate regression coefficient matrix that accounts for the correlations of the response variables. Robustness to outliers is achieved using heavy-tailed t distributions for the multivariate response, and shrinkage is introduced by adding to the negative log-likelihood l1 penalties on the entries of both the regression coefficient matrix and the precision matrix of the responses. Taking advantage of the hierarchical representation of a multivariate t distribution as the scale mixture of normal distributions and the EM algorithm, the optimization problem is solved iteratively where at each EM iteration suitably modified multivariate regression with covariance estimation (MRCE) algorithms proposed by Rothman, Levina and Zhu are used. We propose two new optimization algorithms for the penalized likelihood, called MRCEI and MRCEII, which differ from MRCE in the way that the tuning parameters for the two matrices are selected. Estimating the degrees of freedom when penalizing the entries of the matrices presents new computational challenges. A simulation study and real data analysis demonstrate that the MRCEII, which selects the tuning parameter of the precision matrix of the multiple responses using the Cp criterion, generally does the best among all methods considered in terms of the prediction error, and MRCEI outperforms the MRCE methods when the regression coefficient matrix is less sparse. The second project is motivated by the existence of the skewness in the data for which the symmetric distribution assumption on the errors does not hold. We extend the procedure we have proposed to the case where the errors in the multivariate linear regression follow a multivariate skew-normal or skew-t distribution. Based on the convenient representation of skew-normal and skew-t as well as the EM algorithm, we develop an optimization algorithm, called MRST, to iteratively minimize the negative penalized log-likelihood. We also carry out a simulation study to assess the performance of the method and illustrate its application with one real data example. In the third project, we discuss the asymptotic distributions of the eigenvalues and eigenvectors for the MLE of the scale matrix in a multivariate skew-normal distribution. We propose a statistic for testing whether the skewness vector is proportional to one of the eigenvectors of the scale matrix based on the likelihood ratio. Under the alternative, the likelihood is maximized numerically with two different ways of parametrization for the scale matrix: Modified Cholesky Decomposition (MCD) and Givens Angle. We conduct a simulation study and show that the statistic obtained using Givens Angle parametrization performs well and is more reliable than that obtained using MCD.
597

Using Surface Methods to Understand the Ohaaki Hydrothermal Field, New Zealand

Rissmann, Clinton Francis January 2010 (has links)
After water vapour, CO₂ is the most abundant gas associated with magmatic hydrothermal systems. The detection of anomalous soil temperature gradients, and/or a significant flux of magmatic volatiles, is commonly the only surface signature of an underlying high temperature reservoir. For both heat (as water vapour) and gas to ascend to the surface, structural permeability must exist, as the unmodified bulk permeability of reservoir rock is too low to generate the focussed fluid flow typical of magmatic hydrothermal systems. This thesis reports the investigation into the surface heat and mass flow of the Ohaaki hydrothermal field using detailed surface measurements of CO₂ flux and heat flow. Detailed surface measurements form the basis of geostatistical models that quantify and depict the spatial variability of surface heat and mass flow, across the surface of both major thermal areas, as high resolution pixel plots. These maps, in conjunction with earlier heat and mass flow studies, enable: (i) estimates of the pre-production and current CO₂ emissions and heat flow for the Ohaaki Field; (ii) interpretation of the shallow permeability structures governing fluid flow, and; (iii) the spatial relationships between pressure-induced ground subsidence and permeability. Heat flow and CO₂ flux surveys indicate that at Ohaaki the soil zone is the dominant (≥ 70% and up to 99%) pathway of heat and mass release to the atmosphere from the underlying hydrothermal reservoir. Modelling indicates that although the total surface heat and mass flow at Ohaaki is small, it is highly focused (i.e., high volume per unit area) relative to other fields within the Taupo Volcanic Zone (TVZ). Normalised CO₂ emissions are comparable to other volcanic and hydrothermal fields both regionally and globally. Despite 20 years of production, there is little difference between pre-production and current CO₂ emission rates. However, the similarity of CO₂ emission rates masks a 40% increase in CO₂ emissions from new areas of intense steaming ground that have developed in response to production of the field for electrical energy production. This increase in thermal ground emissions is offset by emission losses associated with the drying up of all steam heated pools and alkali-Cl outflows from the Ohaaki West (OHW) thermal area, in response to production-induced pressure decline. The location of surface thermal areas is governed by the occurrence of buried or partially emergent lava domes, whereas the magnitude of CO₂ flux, mass flow, and heat flow occurring within each thermal area is determined by the proximity of each dome (thermal areas) to major upflow zones. Buried or partially emergent silicic lava domes act as cross-stratal pathways for fluid flow, connecting the underlying reservoir to the surface, and bypassing several hundred metres of the poorly permeable Huka Falls Formation (HFF) caprock. For each dome complex the permeable structures governing fluid flow are varied. At Ohaaki West, thermal activity is controlled by a deep-rooted concentric fracture zone, developed during eruption of the Ohaaki Rhyolite dome. Within the steam-heated Ohaaki East (OHE) thermal area, flow is controlled by a high permeability fault damage zone (Broadlands Fault) developed within the apex of the Broadlands Dacite dome. Structures controlling alkali-Cl fluid flow at OHW also iii appear to control the occurrence and shape of major subsidence bowls (e.g., the Main Ohaaki Subsidence Bowl), the propagation of pressure decline to surface, and the development and localization of pore fluid drainage. Across the remainder of the Ohaaki field low amplitude ground subsidence is controlled by the extent of aquifer and aquitard units that underlie the HFF, and proximity to the margins of the hot water reservoir. The correlation between the extent of low amplitude ground subsidence and the margins of the field reflects the coupled relationship between the hot water reservoir and reservoir pressure. Only where thick vapour-phase zones buffer the vertical propagation of deep-seated pressure decline to the surface (i.e., OHE thermal area), is ground subsidence not correlated with subvertical structural permeability developed within the HFF. This thesis makes contributions to regional and global research on geothermal and hydrothermal systems by: (i) quantifying the origin, mass, and upward transport of magmatic carbon from geothermal reservoirs; (ii) assessing the changes to the natural surface heat and mass flow of the Ohaaki Field following 20 years of production; (iii) establishing the utility of surface CO₂ flux and heat flow surveys to identify major upflow zones, estimate minimum mass flow, and determine the enthalpy of reservoirs; (iv) providing insight into the hydrothermal, structural and lithological controls over hydrothermal fluid flow; (v) demonstrating the influence of extinct silicic lava domes as important structural elements in the localisation of hydrothermal fluid flow; (vi) identifying the hydrostructural controls governing the spatial variability in the magnitude of pressure-induced ground subsidence, from which predictive models of subsidence risk may be defined, and; (vii) developing new technologies and characterising methods used for detailed assessment of surface heat and mass flow.
598

The structural, serviceability and durability performance of variable density concrete panels

Saevarsdottir, Thorbjoerg January 2008 (has links)
Conventional concrete is a poor insulating material but has good thermal mass, while lightweight concrete provides good insulation at the price of thermal mass. Precast concrete wall systems have not been widely used in residential homes due to poor thermal and acoustic performance, despite being high quality products that are easy to construct. The variable density concrete panel was designed to combine good thermal storage, insulation and high quality precast concrete. It is produced from a single concrete mix which is vibrated to get a lightweight top layer and a normal/heavyweight bottom layer. The lightweight layer is the wall exterior, having low thermal conductivity providing good thermal insulation while the normal/heavyweight layer is the dense wall interior, having high specific heat to provide good thermal mass and sufficient strength for construction handling and to withstand service loads. The intention of this research was to estimate the hardened performance; that is the structural, serviceability and durability performance of the variable density concrete panel. Further developments to the mix design were made where the fresh properties were measured and thermal performance estimated on hardened specimens. Most of the major technical concerns were proved not being as severe as first thought, making the production of variable density concrete panels promising. To ensure that the variable density concrete would stratify, the concrete mix had to have defined fresh properties. Defined rheological ranges gave a good indication of the stratification potential, but the degree of stratification was also found to be dependent on the intensity and time of vibration. Slump flow had to be within a certain range to achieve good stratification but this alone did not guarantee stratification. Variable density concrete was found to have adequate strength capacity both in axial compression and in tension for likely service loads but the strength required to withstand handling loads at early ages was not assessed. The strength of the variable density concrete was found to be affected by several factors such as; degree of stratification, relative strength and thickness of the layers, curing environment and amount of defects. As the stratification of the concrete increased the thermal insulation improved whereas the strength decreased. Warping was found not to significantly affect the serviceability of panels despite differential shrinkage within the element. The amount of warping was mainly related to the degree of stratification. Warping decreased with better stratification as more stress and strain was relieved in the lightweight layer. The lightweight concrete was significantly weaker as well as being less stiff than the structural concrete and therefore creeps to follow the structural concrete. The thermal properties aimed for were generally not reached, but these mixes were not designed to optimise the thermal performance and were tested before the concrete was fully dried. This increased thermal conductivity and therefore reduced the measured R-values. Stratified concrete had good absorption resistance, poor permeability properties and was highly porous. If the concrete was over-vibrated it tended to have a rough surface finish that would require a coating. Delamination of the panels was not assessed in this research but is a likely mode of failure.
599

MOLECULAR AND FUNCTIONAL INVESTIGATION OF CANCER-TYPE AND LIVER-TYPE VARIANTS OF ORGANIC ANION TRANSPORTING POLYPEPTIDE 1B3

Thakkar, Nilay 01 January 2015 (has links)
OATP1B3 belongs to the OATP (organic anion transporting polypeptides) superfamily, responsible for mediating the transport of various endogenous and xenobiotic substrates. OATP1B3 was initially reported to be expressed exclusively in the hepatocytes where it mediates the uptake of numerous endogenous substrates (e.g. bile acids, steroid hormone conjugates) and several clinically relevant drugs including anticancer drugs. Later, a number of studies reported that OATP1B3 is also frequently expressed in multiple types of cancers and may be associated with differing clinical outcomes. However, a detailed investigation on the expression, localization and functions of OATP1B3 expressed in cancer has been lacking. In this thesis work, we confirmed that colon and pancreatic cancer cells express a cancer-specific OATP1B3 variant (csOATP1B3), different from OATP1B3 wild-type (WT) expressed in the normal liver. The csOATP1B3 utilizes an alternative transcription initiation site and the translated product of csOATP1B3 lacks the first 28 amino acids at the N-terminus of OATP1B3 WT. Our results show that csOATP1B3 has modest uptake transporter functions and reduced plasma membrane localization compared to OATP1B3 WT. In our efforts to investigate the regulatory mechanism underlying the expression of csOATP1B3, we found that hypoxia inducible factor-1α (HIF-1α) may play a key role in the regulation of csOATP1B3 in colon and pancreatic cancer cells. In a separate study, we tested whether the N-terminal sequence of OATP1B3 WT plays an important role in the membrane trafficking. This is based on the observation that csOATP1B3 lacking the first 28 amino acids at N-terminus of OATP1B3 WT displays a predominantly cytoplasmic localization pattern. Using the constructs with N-terminal truncations and point mutations, we verified that the N-terminus of OATP1B3 WT contains important motifs in its membrane trafficking. In particular, the amino acids within a putative β-turn-forming tetrapeptide appear to be important in regulating the membrane trafficking of OATP1B3 WT. The findings from this thesis work provide important insights into the functional and clinical significance of OATP1B3 in cancer and normal liver.
600

A NON-MARITAL, ROMANTIC RELATIONSHIP DISSOLUTION STUDY

Stork-Hestad, Nicole B. 01 January 2010 (has links)
The present study examines three non-marital, romantic relationship dissolution types: (1) normal dyadic dissolution, (2) fatal attraction dissolution, and (3) social allergen dissolution among a sample of 321 emerging adults, who are between ages eighteen and twenty-nine. Results of an online survey revealed that normal dyadic dissolution occurred in 62%, social allergen dissolution occurred in 27%, and fatal attraction dissolution occurred in 11% of the participants’ relational demises. Results also revealed that there is a surprising amount of overlap between the three dissolution types, and that age is not specifically correlated with a particular dissolution type. However, there are two predicators of dissolution type within an emerging adult population: perceived family support and whether or not the couple cohabitate.

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