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Submerged wood inhabiting macoinvertebrates of the Elm Fork of the Trinity River, Texas: Assemblage analyses, comparisons to the benthic fauna, and a study of Cyrnellus fraternus (Trichoptera: Polycentropodidae)Johnson, Zane B. 08 1900 (has links)
Taxonomic composition and spatio-temporal variability of macroinvertebrates inhabiting snags were examined from an 8-km segment of the Elm Fork of the Trinity River. Seventy-seven macroinvertebrate taxa were collected from submerged wood during the study. Assemblages were highly variable spatially and temporally, especially among seasons. An ordination of species and environment did not find snag taxa to have striking correlations with many of the selected environmental variables, although there were some trends in flow-mediated species distributions. There were significant seasonal differences in the abundances of some taxa, particularly among the Chironomidae (Diptera). The Tribe Orthocladiini was numerically abundant during the winter, while the Tribes Chironomini and Tanytarsini dominated the summer and autumn. Additionally, this study included a secondary production and microdistribution analysis of a population of the caddisfly Cyrnellus fraternus. Distributions of C. fraternus were restricted to snags, the most stable substratum for retreat building and for resisting periodic high waters. Larvae were not found in the soft sand and mud benthic habitats near submerged wood. The insects were multivoltine with a minimum of three generations per year. Pupae were collected July through September and adults emerged from May through October. The population overwintered as larvae. Estimated annual production was 1,015.4 mg/m2/yr. Mean standing stock biomass was 61.24 mg/m2, the cohort production/biomass ratio was 4.59, and the annual production/biomass rate was 16.58/yr for this population. Standing stock biomass ranged from 1.6 to 349.1 mg/m2 during the year and was significantly higher in autumn and summer than winter. Larvae were more abundant in the lower portions of the study area where flow was reduced for much of the year, than in the upper reaches, characterized by higher current velocities. C. fraternus larvae were found in their highest numbers on snags with dense deposits of silt and sand.
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A Chemical Investigation of Lake Dallas to Determine the Factors Influencing Plankton Growth.Welch, Herschel 08 1900 (has links)
A study to determine the organic content of Lake Dallas, and study the influence on plankton growth.
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Chemical Analysis of the Bottom Deposits of Artificial Lakes with Special Emphasis on Lake DallasPatrick, Paul V. 06 1900 (has links)
This study is for the purpose of determining the chemical content of typical artificial reservoir bottom deposits.
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Comparison of Bare Root vs. Potted Plants, Species Selection, and Caging Types for Restoration of a Prairie Wetland, and Quantitative Analysis and Descriptive Survey of Plant Communities and Associations at Lewisville Lake Environmental Learning Area (LLELA), Lewisville, TXBuckallew, Robin R. 05 1900 (has links)
Lewisville Lake Environmental Learning Area (LLELA) is an 809-hectare property in Denton County, TX. A study of the vegetation community identified 466 species in 104 families, with 25% of the species from only two families, Asteraceae and Poaceae. The property demonstrates the characteristics of an early successional community, dominated by weedy species. Prairie communities are dominated by Johnson grass and ragweed, with climax tall grass prairie communities only in areas that have been planted with native grass seed. Forest communities are similarly in an early successional stage, dominated by the hackberry-elm-ash alliance, with small remnants of native Cross Timbers found in isolated patches. Species richness and diversity were highest in the forests and lowest in the wetlands; evenness, though not different across ecosystems, demonstrated a strong seasonal component. The species list was compared with previously reported lists for Denton County, and 256 species identified had not been previously reported for the county. A wetland restoration study was conducted to determine if there was a difference in survival and growth between potted transplants with intact root systems and bare-root transplants. Two different mesh sizes were used for protection, and the success of the different caging was evaluated. Of eight species, only four survived through the second growing season. There was no significant difference in the success of the propagule types for Sagittaria latifolia. The treatments planted with intact root systems showed significantly higher growth and reproduction than the bare-root treatments for Eleocharis quadrangulata, Heteranthera dubia, and Vallisneria americana. There was no survival recorded in the coarse mesh cages, likely due to the presence of crayfish that are able to get through the coarser mesh and feed on the transplants.
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Model poslovnog rešenja za komunikacione aktivnosti primenom”softvera kao usluge (SAAS)" / Business model solution in communication activities through "Software as aservice (SAAS)"Vujović Đermanović Dragana 29 January 2018 (has links)
<p>U radu je istraženo kako čitaoci prihvataju savete na blogovima. U<br />radu je integrisan model prihvatanja tehnologije (eng. Technology<br />Acceptance Model) sa dualnim procesnim modelima informacionog<br />uticaja, a u cilju dobijanja teorijskog modela za prihvatanje saveta. U<br />modelu je istaknut značaj korisnosti i kredibilnosti saveta kao<br />medijatora u procesu prihvatanja saveta.<br />Dualni procesni modeli su u radu primenjeni u cilju otkrivanja<br />faktora koji doprinose korisnosti informacija, u različitom<br />postupku obrade tih informacija. Istraživanje je sprovedeno na<br />SAAS platformi Beeshaper. Primenjena je mešovita metoda<br />istraživanja. Prvo je sproveden intervju na uzorku od 25 blogera od<br />uticaja. Nakon toga je sprovedeno kvantitativno istraživanje sa 356<br />korisnika koji dobijaju savete na blogovima. Istraživanjem je potvrđen<br />predloženi model.<br />Komunikacija na internetu sve više dobija na značaju u poslednjim<br />godinama. Rezultati istraživanja predlažu model za razumevanje<br />transfera znanja na platformi bloga, kroz računarski podržanu<br />komunikaciju.</p> / <p>The paper explores the way readers accept advice on blogs. The paper<br />integrates the Technology Acceptance Model with dual process information<br />model, in order to obtain a theoretical model for advice adoption. The model<br />emphasizes the importance of the usefulness and credibility of eWOM as the<br />mediators in the process of advice adoption.<br />Dual process models are applied in the paper to identify the factors that<br />contribute the usefulness of information, in a different process of elaboration<br />of these information. The research was conducted on the SAAS platform<br />Beashaper. A mixed method of research was conducted. The first part of the<br />reseach was an interview with the sample of 25 influencers. After qualitative<br />part of the study, a quantitative survey was conducted on the sample of 356<br />users who adopted blog advice. The study confirmed the proposed model.<br />Communication on the Internet is gaining significance in the recent years.<br />This research suggest a model for understanding knowledge transfer on the<br />blog platform, through computer-based communication.</p>
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Aspects graphiques de la persuasion technologique : étude des messages persuasifs sur internet pour le recyclage des déchets électroniques / Graphic design of electronic persuasion : study of persuasive messages on the web promoting e-waste recyclingNaczaj, Dimitri 20 December 2018 (has links)
Cette thèse comprend trois expériences et deux prétests (N = 1135) dans lesquelles sont étudiés trois aspects fondamentaux du design statique des messages sur internet : son format (infographie, audio ou texte), sa couleur et sa typographie, sur la thématique du recyclage des déchets électroniques (études 1 et 2) puis à propos de la migration humaine (étude 3).L’étude des aspects graphiques est pertinente si l’on veut augmenter la force persuasive d’un message. Le format joue un rôle prépondérant (étude 1a), permettant à la fois de changer les attitudes, mais aussi d’ancrer ce changement dans le temps. Les couleurs, par contre, ne semblent pas faire varier la force persuasive du message ou amener les lecteurs à agir en faveur du recyclage (étude 1b). La typographie ne semble pas non plus jouer de rôle dans la dynamique persuasive, qu’elle soit jugée lisible ou peu lisible (étude 2). Des pistes théoriques concernant la personnalité des typographies et leur cohérence avec le contexte sont développées.L’analyse des composantes de l’ELM a révélé, dans chaque étude, le fort lien entre l’attitude des individus et leur sentiment de responsabilité personnelle envers la thématique abordée ainsi que leurs connaissances a priori. Nous avons également vu que les leviers de persuasion ne sont pas systématiquement les mêmes selon le besoin de cognition.Globalement, nous suggérons que les messages persuasifs doivent adopter un format permettant une analyse centrale à faible coût cognitif, utilisant une couleur principale et une typographie toutes deux lisibles et cohérentes avec la thématique développée, avec un argumentaire qui renforce le sentiment de responsabilité des lecteurs. / This thesis includes three experiments and two pre-tests (N = 1135) in which three fundamental aspects of static message design on the Internet are studied: its format (infographics, audio or text), its colour and typography, on the theme of electronic waste recycling (studies 1 and 2) and then on human migration (study 3).The study of graphic aspects is relevant if we want to increase the persuasive power of a message. The format plays a major role (study 1a), making it possible to change attitudes and to anchor this change over time. Colours, on the other hand, do not seem to vary the persuasive force of the message or to lead readers to act in favour of recycling (study 1b). Nor does typography seem to play a role in the persuasive dynamic, whether it is considered legible or difficult to read (study 2). Theoretical approaches regarding the personality of typographies and their coherence with the context are developed.The analysis of the components of the ELM revealed, in each study, the strong link between the attitude of individuals and their sense of personal responsibility towards the theme addressed as well as their a priori knowledge. We have also seen that the levers of persuasion are not systematically the same according to the need for cognition.We suggest that persuasive messages should adopt a format that allows for central analysis at low cognitive cost, using a main colour and typography that are both readable and consistent with the theme developed, with arguments that reinforce readers' sense of responsibility.
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Free-boundary simulations of MHD plasma instabilities in tokamaks / Simulations MHD à frontière libre des instabilités plasma dans les tokamaksArtola Such, Francisco Javier 27 November 2018 (has links)
Un des dispositifs les plus prometteurs pour réaliser la fusion contrôlée est le réacteur de type tokamak. Dans ces réacteurs, un plasma chaud ionisé est confiné à l'aide d'un champ magnétique intense. Ce travail de thèse porte sur l'étude d'une classe particulière d'instabilités au sein d'un tokamak. Cette étude est menée par des simulations numériques magnétohydro-dynamiques (MHD). Le code JOREK-STARWALL est adapté et appliqué pour étudier les instabilités dites à frontière libre. Ce type d'instabilités nécessitent un traitement spécial concernant les conditions de bord du plasma, où l'interaction du plasma avec le vide et les structures conductrices environnantes doit être prise en compte. JOREK-STARWALL permet d'étudier la physique de deux instabilités particulières à frontière libre: les modes localisés au bord ("Edge Localized Modes", ELMs) déclenchés par des oscillations de la position verticale du plasma et les évènements de déplacement vertical (Vertical Displacement Events, VDEs). Deux résultats majeurs sont obtenus: 1. Le déclenchement des ELMs par des oscillations de la position verticale est pour la première fois reproduit avec des simulations auto-cohérentes. Celles-ci permettent d'étudier le mécanisme physique sous-jacent à ce phénomène. Les simulations révèlent que pour le projet international ITER, ces ELMs déclenchés sont principalement dus à une augmentation du courant au bord du plasma due au mouvement vertical. 2. Pour les VDEs, plusieurs comparaisons effectuées avec d'autres codes MHD existants montrent un bon accord avec JOREK-STARWALL et permettant ainsi de réaliser des simulations pour estimer la quantité attendue de courants de halo dans ITER / One of the most promising concepts for future fusion reactors is the tokamak. In these devices, a hot ionized plasma is confined with the use of large magnetic fields. The subject of this thesis is the study of a particular type of tokamak instabilities with MagnetoHydroDynamic (MHD) simulations. The code JOREK-STARWALL is adapted and applied to the simulation of the so-called free-boundary instabilities. The investigation of this type of instabilities requires a special treatment for the plasma boundary conditions, where the interaction of the plasma with the vacuum and the surrounding conducting structures needs to be taken into account. In this work, the modelling of the electromagnetic plasma-wall-vacuum interaction is reviewed and generalized for the so-called halo currents. The adapted JOREK-STARWALL code is applied in order to study the physics of two particular free-boundary instabilities: Edge Localized Modes (ELMs) triggered by vertical position oscillations and Vertical Displacement Events (VDEs). Two major results are obtained: 1. The triggering of ELMs during vertical position oscillations is for the first time reproduced with self-consistent simulations. These allow for the investigation of the physical mechanism underlying this phenomenon. The simulations reveal that for the international ITER project, a large-scale tokamak, these triggered ELMs are mainly due to an increase in the plasma edge current due to the vertical plasma motion. 2. For VDEs, several benchmarks are performed with other existing MHD codes showing a good agreement and therefore allowing the performance of ITER simulations to estimate the expected amount of halo currents in ITER
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A Study of the Impacts of Dutch elm disease, Emerald ash borer, and Amur honeysuckle on the Flora of Rush Run Wildlife AreaBetsch, Brody Bly 31 July 2019 (has links)
No description available.
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A Bio-Chemical Comparative Study of the Plankton in Lake Dallas and Pecan CreekBrooks, Benjy Frances 08 1900 (has links)
The purpose of this investigation is to compare the dissolved and suspended organic material in Lake Dallas to that coming into the lake through Pecan Creek.
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Goodness-of-fit test and bilinear modelFeng, Huijun 12 December 2012 (has links)
The Empirical Likelihood method (ELM) was introduced by A. B. Owen to test hypotheses in the early 1990s. It's a nonparametric method and uses the data directly to do statistical tests and to compute confidence intervals/regions. Because of its distribution free property and generality, it has been studied extensively and employed widely in statistical topics. There are many classical test statistics such as the Cramer-von Mises (CM)
test statistic, the Anderson-Darling test statistic, and the Watson test statistic, to name a few. However, none is universally most powerful. This thesis is dedicated to extending the ELM to several interesting statistical topics in hypothesis tests. First of all, we focus on testing the fit of distributions. Based on the CM test, we propose a novel Jackknife Empirical
Likelihood test via estimating equations in testing the goodness-of-fit. The proposed new test
allows one to add more relevant constraints so as to improve the power. Also, this idea can be generalized to other classical test statistics. Second, when aiming at testing the error distributions generated from a statistical model (e.g., the regression model), we introduce the Jackknife Empirical Likelihood idea to the regression model, and further compute the confidence regions with the merits of distribution free limiting chi-square property. Third, the ELM
based on some weighted score equations are proposed for constructing confidence intervals
for the coefficient in the simple bilinear model. The effectiveness of all presented methods are demonstrated by some extensive simulation studies.
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