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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.
461

Measures of growth of discrete rational equations

Al-Ghassani, Asma Said Ahmed January 2010 (has links)
The general scope of this thesis is aimed at investigating certain classes of discrete equations through the analysis of certain characteristics of the solutions of these equations. We construct new methods of analysis based on the growth of these characteristics that let us single out known integrable discrete equations from certain class of equations. These integrable discrete equations are discrete analogues of the famous Painleve equations.
462

Saggi di Economia Applicata e di Economia dello Sviluppo / ESSAYS IN APPLIED AND DEVELOPMENT ECONOMICS

ALACEVICH, CATERINA 27 April 2016 (has links)
La presente tesi di dottorato è articolata in tre capitoli a se stanti che riguardano l’ambito dell’economia applicata e dell’economia dello sviluppo. Il primo capitolo analizza l’impatto intergenerazionale di shock idiosincratici alla situazione lavorativa dei genitori sull'istruzione secondaria dei figli, utilizzando un’indagine longitudinale condotta in Bosnia Erzegovina. Il secondo capitolo tratta delle potenziali conseguenze di lungo termine della guerra civile sulla partecipazione politica. In particolare, l’analisi utilizza le statistiche ufficiali disponibili relative alle elezioni in Bosnia Erzegovina e mostra che nelle municipalità più intensamente colpite dal conflitto, misurato in termini di perdite civili, l’affluenza elettorale e il capitale sociale sono minori. Il terzo capitolo contribuisce alla letteratura sulla “auto-selezione” in termini di salute della popolazione Indiana migrante presente in Inghilterra. L'analisi fornisce evidenza empirica delle differenze in termini di statura ed altri indicatori di salute delle prime e seconde generazioni di migranti in relazione alla popolazione nativa del paese di destinazione, e a quella del paese di origine. / This dissertation is a collection of three self-contained essays in applied and development economics. In the first chapter I evaluate whether educational investments of adolescent offspring are vulnerable to idiosyncratic shocks to parental employment. Specifically, I estimate the short-term impact of parental job loss on children’s enrollment in post-compulsory schooling, introducing a focus on paternal and maternal unemployment, and analysing differential gender specific effects. I further discuss the potential channels of inter-generational transmission with a specific focus on the role played by female labor supply in contexts of developing economies. Using panel data estimation techniques based on four waves of longitudinal household data from Bosnia and Herzegovina, the results show that maternal involuntary employment shocks affects school enrollment of daughters aged 15-18. In the second chapter I analyze the consequences of exposure to civil conflict on voters’ turnout and social participation. Our source of variation in violence exposure is given by war-related civilian fatalities recorded at the municipality level. In a “difference in differences” estimation framework, our results show that the intensity of civil conflict reduces turnout in the medium and long run, up to twenty years after the end of the war. War exposure is also associated with lower generalised trust and worse measures of social participation. The third chapter evaluates height performances of first and second generation migrants of Indian origins in England, with respect to adults and children in India, and the native population at destination. We provide evidence of migrants’ “self selection” on health, and we show that the circumstances in which individuals are born and raised can contribute to the definition of body size, in addition to the genetic channel and to the traits transmitted by maternal characteristics through gestation.
463

Validation of the WAM-model over the Baltic Sea

Berg, Caroline January 2008 (has links)
<p>In order to understand how waves influence the exchange of momentum, latent heat and other parameters, between the ocean surface and the atmosphere, one can use models. A coupling between a wave model and an atmospheric regional climate model, for the Baltic Sea, will be performed at the Meteorology Institute in Uppsala University. The wave model is a state of the art, third generation wave model called WAM.</p><p>The new version of the WAM model (cycle 4) needs to be validated. The aim of this thesis is to perform this validation and also to investigate what meteorological forcing one should use to achieve best results. Two different types of forcing are analyzed, ERA40 reanalysis and the RCA climate model. In order to do this, observations from six different buoys in the Baltic Sea will be compared with the model output from WAM. The parameters that will be compared in this study are significant wave height, direction and peak period.</p><p>A consistent phenomenon for all the buoys is a slightly overestimation by the model of what the rate of this increases with increasing wave height. If one compares the model output when WAM are forced with the RCA climate model and when it is forced with ERA40 reanalysis, the differences between them are notable but not large. ERA40 is slightly better.</p><p>Significant wave height is quite good and gives a reasonably result. Some buoys and periods are better and some are worse. There are some differences for the significant wave height between the east coast and the west coast of Sweden, when forcing the model with RCA. It is slightly better on the west coast. On the contrary, the results from ERA40 are very coherent. The quality of the hindcast for the direction and the peak period, in contrast to the significant wave height, is not that good. The results are not bad, but it only gives a rough picture of the sea state.</p>
464

A study on the acoustic performance of tramway low-height noise barriers : gradient-based numerical optimization and experimental approaches

Jolibois, Alexandre, Jolibois, Alexandre 25 November 2013 (has links) (PDF)
Noise has become a main nuisance in urban areas to the point that according to the World Health Organization 40% of the European population is exposed to excessive noise levels, mainly due to ground transportation. There is therefore a need to find new ways to mitigate noise in urban areas. In this work, a possible device to achieve this goal is studied: a low-height noise barrier. It consists of a barrier typically less than one meter high placed close to a source, designed to decrease the noise level for nearby pedestrians and cyclists. This type of device is studied both numerically and experimentally. Tramway noise barriers are especially studied since the noise sources are in this case very close to the ground and can therefore be attenuated efficiently. The shape and the surface treatment of the barrier are optimized using a gradient-based method coupled to a 2D boundary element method (BEM). The optimization variables are the node coordinates of a control mesh and the parameters describing the surface impedance. Sensitivities are calculated efficiently using the adjoint state approach. Numerical results show that the shapes generated by the optimization algorithm tend to be quite irregular but provide a significant improvement of more than 5 dB (A) compared to simpler shapes. Utilizing an absorbing treatment on the source side of the barrier is shown to be efficient as well. This second point has been confirmed by scale model measurements. In addition, a full scale low height noise barrier prototype has been built and tested in situ close to a tramway track in Grenoble. Measurements show that the device provides more than 10 dB (A) of attenuation for a close receiver located at the typical height of human ears. These results therefore seem to confirm the applicability of such protections to efficiently decrease noise exposure in urban areas
465

Comparative Mapping of QTLs Affecting Oil Content, Oil Composition, and other Agronomically Important Traits in Oat (Avena sativa L.)

Hizbai, Biniam T. 01 November 2012 (has links)
Groat oil content and composition are important quality traits in oats (Avena sativa L). These traits are controlled by many genes with additive effects. The chromosomal regions containing these genes, known as quantitative trait loci (QTL), can be discovered through their close association with markers. This study investigated total oil content and fatty acid components in an oat breeding population derived from a cross between high oil ('Dal') and low oil ('Exeter') parents. A genetic map consisting of 475 DArT (Diversity Array Technology) markers spanning 1271.8 cM across 40 linkage groups was constructed. QTL analysis for groat oil content and composition was conducted using grain samples grown at Aberdeen, ID in 1997. QTL analysis for multiple agronomic traits was also conducted using data collected from hill plots and field plots in Ottawa, ON in 2010. QTLs for oil content, palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2) and linolenic acid (18:3) were identified. Two of the QTLs associated with oil content were also associated with all of the fatty acids examined in this study, and most oil-related QTL showed similar patterns of effect on the fatty acid profile. These results suggest the presence of pleiotropic effects on oil-related traits through influences at specific nodes of the oil synthesis pathway. In addition, 12 QTL-associated markers (likely representing nine unique regions) were associated with plant height, heading date, lodging, and protein content. The results of this study will provide information for molecular breeding as well as insight into the genetic mechanisms controlling oil biosynthesis in oat.
466

Body composition and systematic low-grade inflammation in children : the PLAY study / Rachelle A. Pretorius

Pretorius, Rachelle Ann January 2006 (has links)
Background: Obesity-related diseases are arising as a major problem among children. inflammation has recently been identified to play an important role in the relationship between obesity.- as well as stunting-related diseases. Objectives: The aim of this study was to assess the association between serum tumour necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and C-reactive protein (CRP) concentrations and a variety of cardiometabolic and anthropometric indices of children in a township outside Potchefstroom, South Africa. Methods: Blood samples of 115 girls and 78 boys (mean age 15.6 ± 1.35) in the Physical Activity in the Young (PLAY) study were cross-sectionally analysed. Trained fieldworkers collected the demographic, Tanner growth stage and habitual physical activity information. Physiologists measured the children’s blood pressure. Anthropometric measurements were taken by. trained post-graduate students with level 1 or 2 qualifications in anthropometrics. A standard test battery was administered by trained postgraduate students in Human Movement Science to assess muscular strength. flexibility and endurance of the children. Blood samples were collected, centrifuged and stored frozen until further analyses. Results: Stunted girls had a significantly higher serum TNF-α concentration than the non-stunted girls (p=0.03). The factor analyses showed that the inflammatory. status clustered with the height for age-z-scores (HAZ) scores and the waist-hip-ratio (WHR). The HAZ-score of the over-fat boys (- 1.46) was significantly smaller than the lean boys (- 1.14, p=0.0 1). whereas the over-fat girls had a trend for a smaller HAZ-score (-1.07) than the lean girls (-0.89). No significant differences were found between the over-fat and the lean children-s inflammatory status. TNF-α and CRP levels tended to be higher in the over-fat children than in lean children. The girls' scrum IL-6 and CRP concentrations correlated significantly with their body mass index (BMI) and WHR (p<0.05 )and their TNF-α and IL-6 concentrations correlated significantly with their WHR (p<0.01 and p<0.05, respectively). Conclusion: In comparison to the non-stunted girls, stunted girls had a statistically significantly higher TNF-α concentration. Unusual fat distribution that is found in over-fat and stunted children may be associated with low-grade inflammation in children. More research is needed on these associations with markers of inflammation in a long-term longitudinal study. / Thesis (M.Sc. (Nutrition))--North-West University, Potchefstroom Campus, 2007.
467

Epidemiological Studies of Preeclampsia : Maternal &amp; Offspring Perspectives

Gunnarsdóttir, Jóhanna January 2017 (has links)
Preeclampsia is a placental-related disorder characterized by generalized endothelial activation. Vascular predisposition is associated with the occurrence of preeclampsia and the recurrence risk is substantial. Onset of preeclampsia is preceded by placental hypo-perfusion, and placental over-production of vasoconstrictive agents might explain symptoms such as hypertension and proteinuria. Preeclampsia is associated with the birth of small-for-gestational-age (SGA) infants. The trajectory of postnatal growth in SGA-born children is described as catch-up, but it is unclear whether prenatal preeclampsia is independently associated with postnatal growth. The objectives were: firstly, to study the association between partner change and prior miscarriages on the occurrence of preeclampsia and SGA; secondly, to study postnatal growth in children prenatally exposed to preeclampsia; and thirdly, to address the association between blood pressure (BP) changes during pregnancy and risks of preeclampsia and SGA. Population-based cohort studies were performed with information from the following registers: Swedish Medical Birth Register, Uppsala Mother and Child Database and Stockholm-Gotland Obstetric Database. Associations were estimated with logistic and linear regression analyses, with adjustments for maternal characteristics, including body mass index, pre-gestational diseases and socioeconomic factors. The results were, firstly, that partner change was associated with preeclampsia and SGA birth in the second pregnancy but depended on the outcome of the first pregnancy, and that a history of recurrent miscarriages was associated with increased risks of preeclampsia and SGA. Secondly, prenatal exposure to preeclampsia was associated with increased offspring growth in height during the first five years. This association was also seen in children born with normal birth weight for gestational age. Thirdly, pre-hypertension in late gestation and elevated diastolic BP from early to mid-gestation were both associated with SGA birth. Further, women with pre-hypertension in early gestation without lowered diastolic BP until mid-gestation seemed to represent a risk group for preeclampsia. To conclude, the importance of previous pregnancy outcomes in the antenatal risk evaluation was highlighted. Secondly, the results imply that postnatal growth trajectory is related to maternal preeclampsia, in addition to SGA. Thirdly, the association between BP changes within a normal range and SGA may challenge the clinical cut-off for hypertension in pregnancy.
468

Precise Gravimetric Geoid Model for Iran Based on GRACE and SRTM Data and the Least-Squares Modification of Stokes’ Formula : with Some Geodynamic Interpretations

Kiamehr, Ramin January 2006 (has links)
Iran is one of the most complicated areas in the world from the view of rough topography, tectonic activity, large lateral density and geoidal height variations. The computation of a regional gravimetric geoid model with high accuracy in mountainous regions, especially with sparse data, is a difficult task that needs a special attention to obtain reliable results which can meet the needs of the today geodetic community. In this research different heterogeneous data has been used, which includes gravity anomalies, the high-resolution SRTM Digital Elevation Model (DEM), recently published GRACE Global Geopotential Models (GGMs), geological maps and GPS/levelling data. The above data has been optimally combined through the least-squares modification of Stokes formula with additive corrections. Regarding the data evaluation and refinement, the cross-validation technique has been used for detection of outliers. Also, several GGMs and DEMs are evaluated with GPS/levelling data. The impact of utilizing a high resolution SRTM DEM to improve the accuracy of the geoid model has been studied. Also, a density variation model has been established, and its effect on the accuracy of the geoid was investigated. Thereafter a new height datum for Iran was established based on the corrective surface idea. Finally, it was found that there is a significant correlation between the lateral geoid slope and the tectonic activities in Iran. We show that our hybrid gravimetric geoid model IRG04 agrees considerably better with GPS/levelling than any of the other recent local geoid models in the area. Its RMS fit with GPS/levelling is 27 cm and 3.8 ppm in the absolute and relative senses, respectively. Moreover, the relative accuracy of the IRG04 geoid model is at least 4 times better than any of the previously published global and regional geoid models in the area. Also, the RMS fit of the combined surface model (IRG04C) versus independent precise GPS/levelling is almost 4 times better compared to the original gravimetric geoid model (IRG04). These achievements clearly show the effect of the new gravity database and the SRTM data for the regional geoid determination in Iran based on the least-squares modification of Stokes’ formula. / <p>QC 20100906</p>
469

Efekty lidského kapitálu v rozvojových zemích / Effects of human capital in developing countries

Mouček, Jan January 2015 (has links)
Effects of human capital in developing countries Bc. Jan Mouček Abstract Improving education and health of people living in developing countries is an often discussed topic. We however know relatively little about the effects that investments into schooling and improving the nutrition and hygiene of people in those countries have on their productivity at work. This thesis investigates the effects of four variables representing investment into human capital on income of individuals from Bangladesh and Indonesia. The four studied variables are education, migration, height and Body Mass Index. The thesis aims at comparing results of estimation using instrumental variables estimator with previous similar research. It tries to observe possible differences in size of effects the human capital variables have. It finds however that the instrumental variables used are of insufficient quality for the estimation to yield reliable results. Because the instruments used were almost the same as in underlying works and their quality has not been previously tested the conclusion of this thesis is that further search for correct instrumental variables describing the human capital variables in various countries around the globe is necessary.
470

Problematika hudebnosti v gymnastických programech na UK FTVS / The issue of musicality in gymnastics programs at UK FTVS

Maroušková, Zuzana January 2016 (has links)
Title: The issue of musicality in gymnastics programs at UK FTVS Objectives: Qualify changes in the level of musicality on students due to the intervention program of subjects Rhythmic gymnastics, Gymnastics I - Dance and Adapted movement and dance pedagogy at UK FTVS and present results of testing. Methods: In my thesis I mostly used analytic and synthetic method based on consolidation of data from written and video sources and their organization in content of my thesis and context of time period. The thesis also used an experimental method associated with data collection and their evaluation. The practical part is conceived as testing. Results: Description of the musicality test results. Keywords: Musicality, height of tones, melodic memory, harmonies, rhythmic memory, A. Bentley.

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