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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.
191

條件評估法中處理「不知道」回應之研究 / Analysis of contingency valuation survey data with “Don’t Know” responses

王昱博, Wang, Yu Bo Unknown Date (has links)
本文主要著重在處理條件評估法下,「不知道」受訪者的回應。當「不知道」受訪者的產生機制並未符合完全隨機時,考量他們的真實意向就顯得極為重要。 文中使用中央研究院生醫所在其研究計畫「竹東及朴子地區心臟血管疾病長期追蹤研究」(CardioVascular Disease risk FACtor Two-township Study,簡稱CVDFACTS)第五循環中的研究調查資料。   由於以往的文獻對於「不知道」受訪者的處理,皆有不足之處。如Wang (1997)所提出的方法,就只能針對某種特定的「不知道」受訪者來做處理;而Caudill and Groothuis (2005)所提的方法,由於將「不知道」受訪者的差補與願付價格的估計分開,亦使其估計結果不具備一些好的性質。在本文中,我們提出一個能同時處理「不知道」受訪者且估計願付價格的方法。除了使得統計上較有效率外,也保有EM演算法的一個特性:願付價格模型中的估計參數為最大概似估計值。此外,在加入三要素混合模型(Tsai (2005))後,我們也可避免用到極端受訪者的訊息去差補那些「不知道」受訪者的意向。   在分析願付價格的過程中,我們發現此筆資料的「不知道」受訪者,其產生的機制為隨機,而非為完全隨機,這意謂著不考量「不知道」受訪者的分析結果,必定會產生偏差。而在比較有考量「不知道」受訪者與沒有的情況後,其結果確實應證了我們的想法:只要「不知道」受訪者不是完全隨機產生的,那麼不考量他們必定會產生某種程度的偏差。 / This paper investigates how to deal with “Don’t Know” (DK) responses in contingent valuation surveys, which must be taken into consideration when they are not completely at random. The data we use is collected from the fifth cycle of the Cardiovascular Disease Risk Factor Two-township Study (CVDFACTS), which is a series of long-term surveys conducted by the Institute of Biomedical Sciences, Academia Sinica. Previous methods used in dealing with DK responses have not been satisfactory because they only focus on some types of DK respondents (Wang (1997)), or separate the imputation of DK responses from the WTP estimation (Caudill and Groothuis (2005)). However, in this paper, we introduce an integrated method to cope with the incomplete data caused by DK responses. Besides being more efficient, the single-step method guarantees maximum likelihood estimates of the WTP model to be obtained due to the good property that the EM algorithm possesses. Furthermore, by adding the concept of the three-component mixture model (Tsai (2005)), some extreme information are drawn out when imputing the DK inclinations. In this hypertension data, the mechanism of the DK responses is “Don’t know at random”, which means the analysis of DK-dropped results in a bias. By using our method, the difference between DK-dropped and DK-included is actually revealed, which proves our suspicion that a DK-dropped analysis is accompanied by a biased result when DK is not completely at random.
192

Table tennis event detection and classification

Oldham, Kevin M. January 2015 (has links)
It is well understood that multiple video cameras and computer vision (CV) technology can be used in sport for match officiating, statistics and player performance analysis. A review of the literature reveals a number of existing solutions, both commercial and theoretical, within this domain. However, these solutions are expensive and often complex in their installation. The hypothesis for this research states that by considering only changes in ball motion, automatic event classification is achievable with low-cost monocular video recording devices, without the need for 3-dimensional (3D) positional ball data and representation. The focus of this research is a rigorous empirical study of low cost single consumer-grade video camera solutions applied to table tennis, confirming that monocular CV based detected ball location data contains sufficient information to enable key match-play events to be recognised and measured. In total a library of 276 event-based video sequences, using a range of recording hardware, were produced for this research. The research has four key considerations: i) an investigation into an effective recording environment with minimum configuration and calibration, ii) the selection and optimisation of a CV algorithm to detect the ball from the resulting single source video data, iii) validation of the accuracy of the 2-dimensional (2D) CV data for motion change detection, and iv) the data requirements and processing techniques necessary to automatically detect changes in ball motion and match those to match-play events. Throughout the thesis, table tennis has been chosen as the example sport for observational and experimental analysis since it offers a number of specific CV challenges due to the relatively high ball speed (in excess of 100kph) and small ball size (40mm in diameter). Furthermore, the inherent rules of table tennis show potential for a monocular based event classification vision system. As the initial stage, a proposed optimum location and configuration of the single camera is defined. Next, the selection of a CV algorithm is critical in obtaining usable ball motion data. It is shown in this research that segmentation processes vary in their ball detection capabilities and location out-puts, which ultimately affects the ability of automated event detection and decision making solutions. Therefore, a comparison of CV algorithms is necessary to establish confidence in the accuracy of the derived location of the ball. As part of the research, a CV software environment has been developed to allow robust, repeatable and direct comparisons between different CV algorithms. An event based method of evaluating the success of a CV algorithm is proposed. Comparison of CV algorithms is made against the novel Efficacy Metric Set (EMS), producing a measurable Relative Efficacy Index (REI). Within the context of this low cost, single camera ball trajectory and event investigation, experimental results provided show that the Horn-Schunck Optical Flow algorithm, with a REI of 163.5 is the most successful method when compared to a discrete selection of CV detection and extraction techniques gathered from the literature review. Furthermore, evidence based data from the REI also suggests switching to the Canny edge detector (a REI of 186.4) for segmentation of the ball when in close proximity to the net. In addition to and in support of the data generated from the CV software environment, a novel method is presented for producing simultaneous data from 3D marker based recordings, reduced to 2D and compared directly to the CV output to establish comparative time-resolved data for the ball location. It is proposed here that a continuous scale factor, based on the known dimensions of the ball, is incorporated at every frame. Using this method, comparison results show a mean accuracy of 3.01mm when applied to a selection of nineteen video sequences and events. This tolerance is within 10% of the diameter of the ball and accountable by the limits of image resolution. Further experimental results demonstrate the ability to identify a number of match-play events from a monocular image sequence using a combination of the suggested optimum algorithm and ball motion analysis methods. The results show a promising application of 2D based CV processing to match-play event classification with an overall success rate of 95.9%. The majority of failures occur when the ball, during returns and services, is partially occluded by either the player or racket, due to the inherent problem of using a monocular recording device. Finally, the thesis proposes further research and extensions for developing and implementing monocular based CV processing of motion based event analysis and classification in a wider range of applications.
193

Socioeconomic disparities in children’s cognitive development: Longitudinal dynamics and stress mechanisms

Raffington, Laurel 07 June 2018 (has links)
Individuelle Unterschiede in der kognitiven Entwicklung von Kindern korrelieren mit ihrem sozioökonomischen Status (engl. socioeconomic status, SES). Allerdings hat die bisherige Forschung längsschnittliche Dynamiken meist ignoriert. Des Weiteren sind die Mechanismen, die zu SES–bedingten Diskrepanzen in der kognitiven Entwicklung führen, weitgehend unbekannt. Gemäß einer Hypothese ist es die Dysregulation der Sekretion des Stresshormons Cortisol die SES Unterschiede vermittelt, da niedriger SES robust mit höherem chronischen Stress assoziiert. Die vorliegende Dissertation weist im Längsschnitt nach, dass Veränderungen im Familieneinkommen die kognitive Entwicklung von armen Kindern im späteren Kindesalter vorhersagen (Studie I). Bemerkenswerterweise wirkt kindliche Kognition auch auf Veränderungen im elterlichen Einkommen, was auf bisher vernachlässigte bidirektionale Familiendynamiken hinweist. Zudem liefert die Dissertation querschnittliche empirische Evidenz für die Hypothese, dass ein stressbezogener Mechanismus in SES–bedingten Unterschieden kognitiver Entwicklung involviert ist. Höherer Stress und ein geringeres Einkommen waren beide mit Anzeichen des Hypocortisolismus in Kindern charakterisiert (Studie II und III). Außerdem gab es Hinweise, dass kognitive Kontrolle vor den Effekten von Stress schützen könnte (Studie II). Schließlich zeigt die Dissertation erstmalig, dass hyporeaktive Cortisolprofile in Reaktion auf akuten Stress in ärmeren Kindern mit deren niedrigerer Gedächtnisleistung assoziiert ist (Studie III). Beachtenswert ist, dass Ergebnisse dieser Dissertation nicht auf Umwelt oder genetisch vermittelte Kausalität schließen lassen. In zukünftigen Interventionsstudien sollte weiter untersucht werden, ob Interventionen die Einkommensgewinne stärken, Stress reduzieren oder die Reaktion von Kindern auf akuten Stress verbessern, kognitive Unterschiede im Zusammenhang mit SES verringern. / Individual differences in cognitive development in childhood vary along gradients of socioeconomic status (SES). Yet, research has largely ignored longitudinal dynamics, despite evidence that SES, especially income, also changes over time. Furthermore, fairly little is known about the mechanisms by which SES explains cognitive disparities. Lower SES environments are marked by high chronic stress exposure, which has led to the hypothesis that dysregulation of the stress response system resulting in altered cortisol secretion mediates disparities in cognition. This dissertation provides longitudinal evidence for the notion that family income gains and losses predict poor children’s cognitive development throughout later childhood (Paper I). Remarkably, children’s cognition also predicts their parents’ earning ability, indicating previously neglected bidirectional family dynamics. Moreover, this dissertation provides cross–sectional evidence for a stress mechanism involved in SES disparities of cognitive functioning. Both higher stress and lower income are associated with patterns of hypocortisolism in middle childhood (Paper II & III). Further, cognitive control skills may buffer against the embedding of stress exposure in diurnal cortisol secretion (Paper II). Lastly, cortisol hyporeactivity to stress found in low–income children is uniquely associated with their lower memory performance. Notably, this dissertation does not warrant environmentally– or genetically–mediated assumptions of causality. Future intervention studies should continue to explore whether facilitating family income gains, reducing stress exposure, normalizing cortisol secretion, or improving children’s stress coping by training cognitive control alleviates SES–related disparities in cognition.
194

MICRORGANISMOS SIMBIONTES, MATÉRIA ORGÂNICA E ADUBAÇÃO NITROGENADA NO DESENVOLVIMENTO E NUTRIÇÃO DO MIRTILEIRO CV. CLIMAX EM AMBIENTE PROTEGIDO

Santana, Kamila 24 June 2016 (has links)
Made available in DSpace on 2017-07-25T19:31:00Z (GMT). No. of bitstreams: 1 Kamila Santana.pdf: 1363071 bytes, checksum: 4f5da813f22ced41d3b26851a927779f (MD5) Previous issue date: 2016-06-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The blueberry is an agricultural crops recently introduced in Brazil and lots of researches are turning to develop and adapt it to the country. Due to its low amount of root hair, it forms associations with microorganisms to expand its zone of nutrient uptake, being the nitrogen the most required element. At this work it was observed the interaction of this cultivation with the inoculum Azospirilum brasilense and Trichodema asperellum into different substrates or doses of nitrogen fertilization. The experiment was performed with cv. Climax and the plants conditioned in pots in greenhouse, under trial design of randomized blocks, factorial 3x3. The considered factors were inoculation (A. brasilense, T. asperellum or without inoculation) and formulation of the substrates (5; 20 e 35% of organic matter – hardened cattle manure) or, at the second experiment, inoculation (A. brasilense, T. asperellum or without inoculation) and doses of nitrogen (0, 10 and 15 g f N plant-1 – provided as urea). The larger quantity of organic matter provided the highest averages relating to physiological (transpiration, water use efficiency and carboxylation efficiency) and growth variables (foliar limb area, total foliar area and rate of relative growth), although, for some of them, it has not differed from plants grown with 20% of organic matter. With 30% of O.M., the inoculation with T. asperellum showed superior averages in CO2 assimilation (A), carboxylation efficiency (A/Ci) and rate of relative growth (RRG). The nitrogen doses positively affected A/Ci, clorophyll amounts, foliar area (limb and total) and foliar nitrogen concentration, although it not differing between 10 or 15g of N plant-1. For the accumulation of the nutrients Ca, Mg, S, Fe and Zn, the nitrogen fertilization did not represent higher foliar levels, even though this might be related to a dilution effect. / O mirtileiro é uma cultura recentemente introduzida no Brasil, sendo que várias pesquisas tem-se voltado para seu melhor desenvolvimento e adaptação no país. Por possuir poucos pelos radiculares, forma associações com microrganismos afim de aumentar sua zona de absorção de nutrientes, sendo o nitrogênio o elemento absorvido em maior quantidade. Neste trabalho, observou-se a interação dessa cultura com os inóculos Azospirillum brasilense e Trichoderma asperellum em diferentes substratos ou doses de adubação nitrogenada. O experimento foi realizado com a cv. Clímax e as plantas acondicionadas em vasos, em casa de vegetação, sob delineamento experimental de blocos casualizados em esquema fatorial 3x3. Os fatores analisados foram inoculação (A. brasilense, T. asperellum ou sem inoculação) e formulação dos substratos (5; 20 e 35% de matéria orgânica – esterco bovino curtido) ou, no segundo experimento, inoculação (A. brasilense, T. asperellum ou sem inoculação) e doses de nitrogênio (0, 10 e 15 g de N planta-1 – fornecido como ureia). A maior proporção de matéria orgânica propiciou as maiores médias em relação a variáveis fisiológicas (transpiração, eficiência no uso da água e eficiência de carboxilação) e de crescimento (área de limbo foliar, área foliar total e taxa de crescimento relativo), embora, para outras, não tenha diferido das plantas cultivadas com 20% de matéria orgânica. Com 35% de M.O., a inoculação com T. asperellum apresentou médias superiores em assimilação de CO2 (A), eficiência de carboxilação (A/Ci) e taxa de crescimento relativo (TCR). As doses de nitrogênio influenciaram positivamente A/Ci, teores de clorofila, área foliar (de limbo e total) e concentração foliar de nitrogênio, embora não diferindo entre 10 ou 15g de N planta-1. Para o acúmulo dos nutrientes Ca, Mg, S, Fe e Zn, a adubação nitrogenada não representou maiores teores foliares, embora isto possa estar relacionado a um efeito de diluição.
195

Umweltstress und Erholung in Wohngebieten

Honold, Jasmin 08 October 2013 (has links)
Stadtbewohner sind häufig mit multiplen Umweltbelastungen konfrontiert, die Stress erzeugen und zu einem Gesundheitsrisiko werden können. Dennoch ist wenig über das Zusammenwirken multipler Umweltstressoren und über das gesundheitliche Potential natürlicher Ressourcen bekannt. Diese Arbeit untersucht daher das Zusammenwirken multipler Stressoren und das Potential natürlicher Ressourcen hinsichtlich der psychischen Gesundheit. Auf Basis eines theoretischen Rahmenmodells erfolgten drei Studien in Berlin. Mittels Online-Studie wurden die für die Berliner Bevölkerung subjektiv kritischsten Umweltfaktoren identifiziert. Daran schloss sich eine Raumanalyse von Umweltdaten an, um Straßenblocks mit hohem versus geringen multiplen Belastungsgrad als Untersuchungsstandorte auszuwählen. In diesen Wohnblocks erfolgte eine Fragebogen-Studie. An einer Teilstichprobe wurden ergänzend qualitative Daten und Haar-Cortisol als objektiver Indikator für chronischen Stress gewonnen. Es zeigte sich, dass multiple Stressoren oder Ressourcen räumlich und zeitlich kovariieren. Die Bewohner hoch belasteter Blocks verhalten sich gesundheitsschädlicher als die Bewohner gering belasteter Blocks, unterscheiden sich jedoch nicht in ihrer Gesundheit. Allerdings besteht ein Zusammenhang zwischen der wahrgenommenen Luftverschmutzung und der subjektiven Gesundheit. Zudem weisen Personen, die sich durch Luftverschmutzung beeinträchtigter, belästigter oder gefährdeter fühlen, höhere Cortisol-Niveaus auf. Dieser Zusammenhang besteht nur bei objektiv hoher, nicht aber bei geringer Luftbelastung, was chronischen Umweltstress mit gesundheitlichen Folgen nahelegt. Schließlich sind der Blick auf eine hohe Quantität unterschiedlicher Vegetationsarten von der Wohnung aus, und die regelmäßige Nutzung spezifischer Grünflächen mit geringerem Cortisol-Niveau und teilweise mit höherer Lebenszufriedenheit assoziiert. Es werden mögliche Implikationen für eine nachhaltige Stadtentwicklung diskutiert. / City residents are often exposed to multiple environmental burdens that may cause stress and thereby pose a health risk. However, little is known about the co-occurrence of stressors, and on the health potential of natural resources. Thus, the aim of this study is to investigate the co-occurrence of multiple environmental burdens and the potential of natural resources with respect to the mental health of city residents. Based on a comprehensive theoretical model three consecutive studies were conducted in Berlin. An online survey facilitated the identification of critical local environmental factors. Subsequently a spatial analysis was conducted using a Geographic Information System in order to select neighborhood street blocks with high versus low multiple burden levels. A household survey was conducted in the selected study sites that additionally assessed the perceived level of other locally relevant burdens. Qualitative data and hair cortisol level as an objective indicator of chronic stress, were supplemented in a subsample. Results showed that either multiple stressors co-occurr or multiple resources are co-present. Residents from high-burden blocks behave in a less healthy manner than residents from low-burden blocks, but they do not differ in regard to health. However, perceived air pollution is related to perceived health. Moreover, individuals who feel more impaired, annoyed, or at risk by air pollution have higher cortisol levels. This relation exists with a high level of objective air pollution only, while no such relation exists when objective air pollution is low. This finding suggests chronic environmental stress with detrimental health consequences. Finally, residents whose homes have views onto high amounts of diverse kinds of vegetation, as well as who regularly use a park or a vegetated way have lower cortisol levels and partly report higher life satisfaction. The results have implications for sustainable urban development.
196

The potential of Lupinus angustifolius cv. Uniharvest, in Canterbury, as a summer greenfeed for lambs

Burtt, Elizabeth S. January 1981 (has links)
Two trials using Lupinus angustifolius cv. Uniharvest were conducted in the summer of 1978-1979 at Lincoln College, Canterbury. From the first trial, designed to measure dry matter accumulation and changing nutritive value of lupins with time, a maximum dry matter yield of just under 990 kg ha⁻¹ was obtained 150 days after sowing. Peak digestibility was 65.0 per cent and was recorded at 125 days after sowing. Protein concentration was highest in the young plant (28.75 per cent at 45 days after sowing) and declined after this, but highest total nitrogen yield coincided with peak dry matter accumulation. In the second trial, lupins at 60 and 100 plants m⁻² were grazed with weaned lambs at each of four successive stages of the plants' growth - pre-flower, primary flower, secondary flower and green pod (post-flower). Highest dry matter accumulation,at just under 1 000 g m⁻², occurred at the green pod stage, and peak protein concentration of 23.7 per cent at the pre-flower stage (lower density). Digestibility was highest at the pre-flower stage (higher density) and the metabolizable energy concentration was also highest in the pre-flower high density plots. Regrowth of lupins following grazing occurred in plots which had been grazed at the pre- and primary flower stage. Maximum total dry matter accumulation from the first grazing combined with the regrowth was 1 350 g m⁻². Digestibility, protein and metabolizable energy concentration of the regrowth was at acceptable levels for animal growth. From the results obtained, and those of other workers, both in New Zealand and overseas, it is suggested that lupins may have considerable potential as a high quality summer forage crop for grazing of young lambs.
197

Development of electrochemical ZnSe Quantam dots biosensors for low-level detection of 17β-Estradiol estrogenic endocrine disrupting compound

Jijana, Abongile Nwabisa January 2010 (has links)
<p>The main thesis hub was on development of two electrochemical biosensors for the determination of 17&beta / -estradiol: an estrogenic endocrine disrupting compound. Endocronology have significantly shown that the endocrine disruptors contribute tremendously to health problems encountered by living species today, problems such as breast cancer, reproductive abnormalities, a decline in male population most significant to aquatic vertebrates, reduced fertility and other infinite abnormalities recurring in the reproductive system of mostly male species. The first biosensor developed for the detection of 17&beta / -estradiol endocrine disrupting compound / consisted of an electro-active polymeric 3-mercaptoprorionic acid capped zinc selenide quantum dots cross linked to horseradish peroxidase (HRP) enzyme as a bio-recognition element. The second biosensor developed was comprised of cysteamine self assembled to gold electrode, with 3-mercaptopropionic acid capped zinc selenide quantum dots cross linked to cytochrome P450-3A4 (CYP3A4) enzyme in the presence of 1-ethyl-3-(3- dimethylaminopropyl)carbodiimide hydrochloride and succinimide.</p>
198

Development of electrochemical sensors containing bimerallic silver and gold nanoparticles

Mailu, Stephen Nzioki January 2010 (has links)
<p>In this work, a simple, less time consuming electrochemical method in the form of an electrochemical sensor has been developed for the detection of PAHs. The sensor was fabricated by the deposition of silver-gold (1:3) alloy nanoparticles (Ag-AuNPs) on ultrathin overoxidized polypyrrole (PPyox) film which formed a PPyox/Ag-AuNPs composite on glassy carbon electrode (PPyox/Ag-AuNPs/GCE). The silver-gold alloy nanoparticles deposited to form the composite were chemically prepared by simultaneous reduction of silver nitrate (AgNO3) and chloroauric acid (HAuCl4) using sodium citrate and characterized by UV-visible spectroscopy technique which confirmed the homogeneous formation of the alloy nanoparticles.</p>
199

The use of cyclodextrin template-based metal oxide nanomaterials in the development of electrochemical sensors for phenolic endocrine disruptor compounds

Masikini, Milua January 2010 (has links)
<p>Iron oxide nanoparticles were prepared using co-precipitation method in the presence and absence of beta-cyclodextrin (&beta / -CD). Such materials were characterized using transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), attenuated total reflection Fourier transform infrared (ATR-FTIR), X-ray diffraction (XRD), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA). The TEM shows that the surface morphology has no difference between nanoparticles prepared in the presence and absence of beta-cyclodextrin (&beta / -CD), amorphous particles with high surface area and dimensions of about 100 nm by 500 nm. The amorphous states of nanoparticles are confirmed further by XRD. The ATR-FTIR analysis confirms inclusion complex between &beta / -CD and nanoparticles.</p>
200

The use of cyclodextrin template-based metal oxide nanomaterials in the development of electrochemical sensors for phenolic endocrine disruptor compounds

Masikini, Milua January 2010 (has links)
<p>Iron oxide nanoparticles were prepared using co-precipitation method in the presence and absence of beta-cyclodextrin (&beta / -CD). Such materials were characterized using transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), attenuated total reflection Fourier transform infrared (ATR-FTIR), X-ray diffraction (XRD), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA). The TEM shows that the surface morphology has no difference between nanoparticles prepared in the presence and absence of beta-cyclodextrin (&beta / -CD), amorphous particles with high surface area and dimensions of about 100 nm by 500 nm. The amorphous states of nanoparticles are confirmed further by XRD. The ATR-FTIR analysis confirms inclusion complex between &beta / -CD and nanoparticles.</p>

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