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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.
381

Inheritance of Oil Production and Quality Factors in Peant (Arachis hypogaea L.)

Wilson, Jeffrey Norman 16 December 2013 (has links)
Peanut (Arachis hypogaea L.) has the potential to become a major source of biodiesel but for market viability, peanut oil yields must increase and specific quality requirements must be met. Oil yield in peanut is influenced by many components, including oil concentration, seed mass, and mean oil produced per seed. All of these traits can be improved through selection as long as there is sufficient genetic variation. Thus, elucidating the genetics of oil concentration, seed mass, and mean oil produced per seed in peanut is essential to advancing the development of genotypes with high oil yields. Additive genetic effects were predominant for oil concentration in two generation means analyses involving a proprietary high oil breeding line and additive genetic variance was highly significant in a complete four-parent diallel analysis. Genetic variance for weight of 50 sound mature kernels (50 SMK) and mean oil produced per SMK (OPS) was additive the diallel analysis. Narrow-sense heritability estimates were high for oil concentration in both the diallel and generation means analyses. Narrow-sense heritability was also high for 50 SMK, but was low for OPS. The low OPS heritability estimate was caused by the negative correlation between oil concentration and seed mass. Consequently, oil concentration and seed mass can be improved through early-generation selection, but large segregating populations from high oil crosses will be needed to identify progeny with elevated oil concentrations that maintain acceptable seed sizes. Increasing the ratio of oleic to linoleic acid (O/L) in peanut oil and reducing the long chain saturated fatty acid concentration (which includes arachidic, behenic, and lignoceric acids) produces high quality, stable methyl esters for biodiesel. Therefore, elucidating the inheritance of these factors and their relationships in peanut populations segregating for high oil is critical. The results from generation means analysis confirm that the high-oleic trait is under simple genetic control and can be manipulated through selection. Oil concentration was negatively correlated with oleic acid concentration in the F2 generations of both crosses and positively correlated with arachidic acid in most of the segregating generations that were evaluated. Therefore, developing a peanut genotype high in oil and oleic acid concentration that has reduced long chain saturates will require the evaluation of large numbers of segregating progeny.
382

Characterization of a novel pre-pore loop antibody against rat TRPV1

Hua, Pierce. January 2009 (has links)
Splice variants of the transient receptor potential vanilloid type-1 (TRPV1) channel appear to be involved in the physiological detection of extracellular fluid (ECF) osmolality in the supraoptic nucleus (SON) and organum vasculosum lamina terminalis (OVLT). It remains to be determined whether these splice variants are directly involved as pore-forming proteins in the osmosensory transduction complex. Since these TRPV1 splice variants are not sensitive to capsaicin antagonists, such as capsazepine (Sharif Naeini et al., 2007), novel tools that specifically interfere with ion permeation through TRPV1 are required for functional studies on the involvement of this channel. In this study, we developed rabbit polyclonal antibodies targeting specifically the extracellular pre-pore loop region of rat TRPV1 (PH-4281). Histological results showed that PH-4281 is specific to rat TRPV1 and TRPV1 expression is found in regions that are known to be osmosensitive. PH-4281 could be used as a specific tool to study the osmosensory transduction complex.
383

Metallhalter i snäckor från Östersjön : En undersökning av säsongskillnader i metallhalter hos snäckor från Östersjön

Nilsson, Jannie January 2013 (has links)
The purpose of this study was to investigate if there is a seasonal difference in metal concentrations in marine gastropods. Metals that were studied were chromium, copper, nickel and zinc. Gastropods were collected at one contaminated site and one reference site. For the contaminated site Rönnskärsverken, Skellefteå, Sweden, was chosen because of its long history as location for a smelter. Kylören, Umeå, Sweden, was chosen as reference site.  The gastropods were collected on two occasions at each site, the first time in the beginning of June and the second time in the end of August. The gastropods were then removed from their shells and the tissue was analyzed spectrometrically for metal content after acid-digestion. The results from the analysis showed unsurprisingly that metal contamination was higher at the contaminated site than at the reference site. More interestingly, it was also found that there are seasonal differences in almost every metal included in the study. Nickel and chromium concentrations were significantly increased (P<0, 05) in the end of the summer and the zinc concentration had the highest value in June in Rönnskärsverken but the highest value in August for the reference site. As only exception, copper concentration did not show any seasonal variation in snail tissue. In conclusion this study shows that there are seasonal differences in metal concentrations in marine gastropods but the differences are not consistent and differs from metal to metal if the concentration is increased in the beginning or the end of summer.
384

Gadolinium Concentration Analysis in a Brain Phantom by X-Ray Fluorescence

Almalki, Musaed Alie Othman January 2009 (has links)
The study was conducted to develop a technique that measures the amount of gadolinium based contrast agent accumulated in a head tumour by x-ray fluorescence, while a patient is exposed to neutrons or during external beam radiotherapy planning. In this research, measurements of the gadolinium concentration in a vessel simulating a brain tumour located inside a head phantom, by the x-ray fluorescence method were taken, where the Magnevist contrast medium which has gadolinium atom, in the tumour vessel, was excited by a 36 GBq (0.97 Ci) 241Am source that emits gamma rays of 59.54 keV, in 35.7 % of it’s decays, resulting the emission of characteristic fluorescence of gadolinium at 42.98 keV that appeared in the X-ray fluorescence spectrum. A Cadmium Telluride (CdTe) detector was used to evaluate and make an analysis of the gadolinium concentration. Determinations of the gadolinium content were obtained directly from the detector measurements of XRF from gadolinium in the exposed tumour vessel. The intensity measured by the detector was proportional to the gadolinium concentration in the tumour vessel. These concentrations of gadolinium were evaluated for dose assessment. The positioning of the head phantom was selected to be in the lateral and vertex positions for different sizes of tumour vessels. Spherical tumour vessels of 1.0, 2.0, 3.0 cm and an oval tumour vessel of 2.0 cm diameter and 4.0 cm length, containing the gadolinium agent, contained concentration between 5.62 to 78.63 mg/ml. They were placed at different depths inside a head phantom at different positions in front of the detector and the source for the measurements. These depths ranged from 0.5 cm to 5.5 cm between the center of the tumour and interior wall of the head phantom surface. The total number of measurements in all four sizes of the tumour vessel was 478; 78 examinations of a 1.0 cm spherical tumour vessel, 110 examinations of a 2.0 cm spherical tumour vessel, 150 examinations of a 3.0 cm spherical tumour vessel and 140 examinations of a 2.0 x 4.0 cm ellipsoid tumour vessel. To measure the size and the shape of the tumour by the alternative radiographic method, a general x-ray machine with radiograph film was used. Based on that, the appropriate shape of concentration could be selected for therapy. The differences of optical density in the x-ray films showed that the noise was increased with low concentration of the Gd. Because radiographic film may be subjected to different chemical processes where the darkness will be affected, these measurements would be very hard to be quantitative. Accordingly it is difficult to use the film for Gd concentrations. The obtained data show that the method works very well for such measurements.
385

The Effect of Nanoparticle Concentration on Thermo-physical Properties of Alumina-nitrate Nanofluid

Shao, Qian 02 October 2013 (has links)
The objective of this study was to determine how Al2O3 nanoparticle concentration affected the specific heat, heat of fusion, melting point, thermal diffusivity and thermal conductivity of Alumina-Nitrate nanofluids. Al2O3 nanoparticles were dispersed in a eutectic of sodium nitrate and potassium nitrate (60:40 for mole fraction) to create nanofluids using a hot plate evaporation method and an air dryer method. The nominal Al2O3 (alumina) mass fraction was between 0 and 2%, and was determined as the ratio of the mass of Al2O3 nanoparticles to the total mass of the nanofluid. After the preparation of the nanofluids, Neutron Activation Analysis (NAA) was used to measure the actual Al2O3 mass fraction in the nanofluids. The specific heat, heat of fusion, and melting point were measured with a Modulated Differential Scanning Calorimeter (MDSC). The thermal diffusivity and thermal conductivity were measured with Laser Flash Analysis (LFA). The MDSC results showed that the addition of Al2O3 nanoparticles enhanced the specific heat of the nanofluids synthesize from both methods. There was a parabolic relation between the specific heat and the Al2O3 mass fraction for the nanofluids synthesized from the hot plate evaporation method, with a maximum 31% enhancement at 0.78% Al2O3 mass fraction. The nanofluids synthesized from the air dryer method also resulted in enhanced specific heats which were higher at the same Al2O3 mass fraction than those of the nanofluids synthesized from the hot plate evaporation method. It was not determined why this enhancement occurred. The results also showed that the introduction of Al2O3 nanoparticles had no significant effect on the heat of fusion and melting point of the nanofluids synthesized from either method. The LFA results showed that adding Al2O3 nanoparticles decreased the thermal diffusivity and the thermal conductivity of the nitrate eutectic.
386

Can Lensing Measure The Shape Of Dark Matter Halos?

Hussain, Uzair January 2012 (has links)
The aim of this project was to explore the shapes of dark matter halos using high resolution N-body simulations. One of the main aspects explored was how well the shape can be measured through weak lensing. To explore this, simulations were run using the GADGET-2 code \cite{SPRING05} and a method used to measure ellipticities was tested \cite{oguri1}. It was found that Large Scale Structure along the line of sight diluted the measurements and made halos appear more spherical. On the other hand, substructure close to the halo introduced a bias where intrinsically elliptical halos appeared to be slightly more spherical and intrinsically spherical halos appeared to be slightly more elliptical. The effects of projection on concentration were also explored, it was concluded that halos which are most elliptical in 3D tend to appear the most concentrated in projection. Finally, we tested the possibility of using shape or concentration measurements to help break the degeneracy in $\Omega_M$ and $\sigma_8$. We found that this may be possible with $\sim$ 3000-4000 shape measurements or $\sim$ 400-500 concentration measurements.
387

東歐國家銀行業市場結構與競爭程度分析 / Market structure and competitive conditions of the banking industry in Eastern European countries

李維傑 Unknown Date (has links)
Eastern European countries have experienced many political upheavals and economic reforms since their declaration of independence of the U.S.S.R. Our study is intended for a series of estimations concerning the market structure of the banking in the Eastern European countries. Besides, we also attempt to assess the transformation of the competitive conditions of the banking industries in these countries. We employ three different methods for the assessment: The Panzar-Rosse Model, the Lerner index and the structural indicators (Concentration Ratio and HHI). We also use quantile regression to estimate the change of the H statistics corresponding to different deciles of the bank revenues beside the standard regression. The estimation results of the H statistics and the Lerner indice both indicate the banking markets of the Eastern European countries are characterized as monopolistic competition. Profitable banks in some countries face keener competition in the market. Besides, the Lerner index is affected by some variables, and tends to show the consistent estimation results with the H statistic in general. On the other hand, the structural indicators reveal a descending concentration in most Eastern European countries. However, the comparison between structural and non-structural methods does not support the general view that concentration undermines competition.
388

対向流拡散火炎中のPAHs生成に与える酸素濃度の影響

長谷川, 義朗, HASEGAWA, Yoshiro, 中村, 祐二, NAKAMURA, Yuji, 山下, 博史, YAMASHITA, Hiroshi 05 1900 (has links)
No description available.
389

Reaktionszeitvariabilität als Indikator von Konzentrationsleistungen

Flehmig, Hagen C. 02 August 2010 (has links) (PDF)
Die vorliegende Arbeit enthält fünf Studien, die einen Beitrag zur Aufklärung der Determinanten individueller Differenzen beim konzentrierten Arbeiten leisten sollten. Im Unterschied zu bisherigen Arbeiten lag der Schwerpunkt hier nicht allein auf der Frage nach dem Zusammenhang handelsüblicher Konzentrationstests mit entsprechenden Zielkriterien (z. B. selbstberichtete Konzentration im Alltag) sondern auf Aufgabenvariablen, welche experimentell manipuliert wurden. Studie 1 untersuchte, ob sich für alternative Kennwerte der Leistung in Konzentrationstests ausreichende psychometrische Gütekriterien zeigen lassen. Von den untersuchten Kennwerten zeigte sich der Variationskoeffizient der Reaktionszeit (RTCV) als ausreichend retestreliabel und unabhängig von klassischen Kennwerten konzentrierten Arbeitens (Tempo und Fehlerneigung). RTCV erwies sich als Maß der Temposchwankung als brauchbarer Indikator für eine Leistungsdimension konzentrierten Arbeitens, die Informationen über die klassischen Konzentrationsfacetten hinaus liefert. In Studie 2 ging es um selbstberichtete Konzentration im Alltag, insbesondere um Zusammenhänge mit klassischen Persönlichkeitsmerkmalen. Der oft berichtete positive Zusammenhang zwischen Neurotizismus und selbstberichteter Fehlerneigung im Alltag konnte nicht nur repliziert werden, sondern auf der Ebene von Subfacetten differenziert werden. Neurotizismus war hauptsächlich mit einer speziellen Form kognitiver Fehlleistungen assoziiert, nämlich mit spontan auftretenden Intrusionen aus dem Langzeitgedächtnis, welche das Arbeitsgedächtnis zeitweilig präokkupieren und zu temporärer Leistungsminderung im Alltagsleben führen können. Die Studien 3 bis 5 hatten das Ziel, eine Reihe von experimentellen Aufgabenvariablen in Konzentrationstests hinsichtlich ihrer Bedeutung für die Retestreliabilität und die Validität zu untersuchen. Es ging unter anderem um Zusammenhänge zwischen Aspekten der Leistung im Test und Aspekten der Persönlichkeit und Fehlerneigung im Alltag. Die experimentelle Anordnung erlaubte eine Prüfung der Annahme von M. W. Eysenck et al. (2007), dass hoher Neurotizismus mit einer Leistungsminderung in auf Wahlreaktionen basierenden Aufgabenformen einhergeht, welche mit zunehmender Itemschwierigkeit größer werden sollte. Diese Annahme wurde geprüft für den Fall eines großen Itemsets (Studie 3: viele Items sollten das Lernen von S-R Verbindungen verhindern, so dass der Einsatz von zusätzlichen Verarbeitungsressourcen auch tatsächlich zu mehr Fehlern führen sollte), für den Fall der Testverlängerung (Studie 4: andauernde Informationsverarbeitung sollte einen differentiellen Ermüdungseffekt evozieren) und auch für den Fall einer vergleichsweise erhöhten Belastung des Arbeitsgedächtnisses (Studie 5). Entgegen der Annahme von M. W. Eysenck et al. (2007) führte ein großes Itemset zu schnelleren Reaktionen im Konzentrationstest bei Personen mit hohem Neurotizismus; hingegen konsistent mit der Annahme von M. W. Eysenck et al. (2007) führte ein großes Itemset zu mehr Fehlern im Konzentrationstest bei Personen mit hohem Neurotizismus. Eine Testverlängerung führte nicht zu persönlichkeitsbezogenen Unterschieden in der Leistung. Eine Erhöhung der Itemschwierigkeit jedoch evozierte einen deutlichen Zusammenhang zwischen Neurotizismus und Reaktionszeitvariabilität. Wenn man hohe Reaktionszeitvariabilität ebenfalls als einen Marker für ineffizientes Arbeiten ansieht, dann kann das Modell von M. W. Eysenck et al. (2007) als partiell unterstützt angesehen werden. Außerdem stand die Frage nach der konvergenten Validität zwischen selbstberichteter Konzentration im Alltag und objektiv getesteter Konzentrationsleistung im Vordergrund. Da subjektive und objektive Konzentration das gleiche Konstrukt beanspruchen, jedoch oft keine entsprechenden Zusammenhänge gefunden wurden, stellte sich die Frage, welche experimentellen Aufgabenfaktoren für den Zusammenhang kritisch sind. Die Frage konnte zum Teil beantwortet werden, denn es zeigte sich konsistent über alle Studien hinweg ein moderater positiver Zusammenhang zwischen den Werten des Cognitve Failures Questionnaire (CFQ) und RTCV, nicht jedoch zwischen CFQ und den traditionellen Kennwerten Tempo und Fehlerneigung. Eine Erhöhung der Itemschwierigkeit im Konzentrationstest ließ diese Korrelationen besonders hervortreten (Studie 5). Dies hat Implikationen für die Frage, mit welchem Aufgabenmaterial das Konstrukt Konzentration am besten erfasst werden kann. Einige Autoren argumentieren für den Einsatz von komplexem Material (da die diagnostische Breite größer ist); andere Autoren jedoch argumentieren für besonders einfache Aufgabenformen (da komplexere Aufgabenformen nicht die reine Konzentration messen und die Korrelationen zu anderen Konstrukten wie Intelligenz immer größer werden). Die wiederholt gezeigten Zusammenhänge zwischen Reaktionszeitvariabilität und CFQ leisten entsprechend einen wichtigen Beitrag zur Konstruktvalidität von Konzentrationstests, da konventionelle Testverfahren bisher nur die traditionellen Kennwerte Tempo und Fehlerneigung verwendeten.
390

Effect of concentration, pH and added chelating agents on the colloidal properties of heated reconstituted skim milk

Chandrapala, Janage Jayani Sandamau January 2008 (has links)
The thermal processing of milk changes the composition and surface properties of the colloidal particles present and alters the physical properties of the milk. Whilst some changes such as those used to improve the texture of products such as yoghurt and are desirable, others such as gel formation during the manufacture of Ultra-High Temperature milk are highly undesirable. This work aims to characterize the effects of milk composition and pH on the chemical and physical changes that occur when milk is heated in order to understand and control the effect of thermal processing on the functional properties of the milk. Particularly important are: (i) the changes to the integrity of the casein micelles and the extent to which they are reversible on cooling of the heated milk, (ii) the changes to the speciation of the components of the serum as they re-equilibrate in response to the changed environment during heating and on cooling, (iii) the heat-induced denaturation of the whey proteins, (iv) the interaction between the components of the micelles and those in the milk serum, particularly those interactions that lead to aggregation or other changes that affect the functional properties of the milk on heating. This project includes thermal treatment (90°C/10 min) of control skim milk solutions (9% Milk Solids Non Fat) with or without addition of calcium chelating agents (orthophosphate (Pin) & Ethylenediaminetetraacetic acid (EDTA)) and concentrated skim milk solutions (up to 21% MSNF). The pH range chosen was 6.2 to 7.2. Almost all of the studies on heat stability to date have been carried out by heating the milk and determining the changes that have occurred after the milk is cooled. This project is focussed on the direct measurements in real time of the changes that occur at the exact temperature. The experimental techniques included pH, calcium activity and 31P NMR measurements at high temperatures to investigate the consequences to the change in mineral speciation, Size Exclusion Chromatography in combination with SDS-PAGE analysis for protein speciation during heating and Diffusing Wave Spectroscopy and viscosity measurements to determine the heat stability of milk systems. pH and calcium activity decreased with increase in temperature for all the milk systems studied. These changes were largely reversible as enough time was given for equilibration. pH and calcium activity changes during heating are a function of milk composition. The quantity, size and the composition of the protein aggregates present in the serum phase after mild centrifugation (~33,000g) of heated (90°C/10min) milk solutions were found to be a function of pH and milk composition (including the consequent differences in speciation of the components of milk). DWS and the viscosity measurements showed that pH at the temperature of heating is one of the primary determinants in influencing the aggregation of the proteins, which led to thermal stability of milk systems. Hence, changing the milk composition resulted in differences in pH at the temperature of heating, which led to different behaviours of heat stability of milk systems. Careful control of the composition of milk and thereby the pH at the temperature of heating allows a greater control of thermal stability of milk systems.

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