Host and Environmental Correlates of Multi-Drug Resistance in Kenyan Children with Acute Bacterial Diarrhea

Thesis (Master's)--University of Washington, 2016-06

Divergent environments and population bottlenecks fail to generate premating isolation in Drosophila pseudoobscura

While the feasibility of bottleneck-induced speciation is in doubt, population bottlenecks may still affect the speciation process by interacting with divergent selection. To explore this possibility, I conducted a laboratory speciation experiment using Drosophila pseudoobscura involving 78 replicate populations assigned in a two-way factorial design to both bottleneck (present vs. absent) and environment (ancestral vs. novel) treatments. Populations independently evolved under these treatments and were then tested for assortative mating and male mating success against their common ancestor. Bottlenecks alone did not generate any premating isolation, despite an experimental design that was conducive to bottleneck-induced speciation. Premating isolation also did not evolve in the novel environment treatment, neither in the presence nor absence of bottlenecks. However, male mating success was significantly reduced in the novel environment treatment, both as a plastic response to this environment and as a result of environment-dependent inbreeding effects in the bottlenecked populations. Reduced mating success of derived males will hamper speciation by enhancing the mating success of immigrant, ancestral males. Novel environments are generally thought to promote ecological speciation by generating divergent natural selection. In the current experiment, however, the novel environment did not cause the evolution of any premating isolation and it reduced the likelihood of speciation through its effects on male mating success.

The effect of timing and severity of water deficit on growth, development, yield accumulation and nitrogen fixation of mungbean

Mungbean (Vigna radiata L.), as a dryland grain legume, is exposed to varying timing and severity of water deficit, which results in variability in grain yield, nitrogen accumulation and grain quality. In this field study, mungbean crops were exposed to varying timing and severity of water deficit in order to examine: (1) contribution of the second flush of pods to final grain yield with variable timing of relief from water deficit, (2) the sensitivity to water deficit of the accumulation of biomass and nitrogen (N) and its partitioning to grain, and (3) how the timing of water deficit affects the pattern of harvest index (HI) increase through pod filling. The results showed that the contribution of the second flush to final yield is highly variable (1-56%) and can be considerable, especially where mid-season stress is relieved at early pod filling. The capacity to produce a second flush of pods did not compensate fully for yield reduction due to water stress. Relief from mid-season stress also resulted in continued leaf production, N-2 fixation and vegetative biomass accumulation during pod filling. Despite the wide variation in the degree of change in vegetative biomass and N during pod filling, there were strong relationships between grain yield and net-above-ground biomass at maturity, and grain N and above-ground N at maturity. Only in the extreme situations were HI and nitrogen HI affected noticeably. In those treatments where there was a large second flush of pods, there was a pronounced biphasic pattern to pod number production, with HI also progressing through two distinct phases of increase separated by a plateau. The proportion of grain yield contributed to by biomass produced before pod filling varied from 0 to 61% with the contribution greatest under terminal water deficit. There was a larger effect of water deficit on N accumulation, and hence N-2 fixation, than on biomass accumulation. The study confirmed the applicability of a number of long-standing physiological concepts to the analysis of the effect of water deficit on mungbean, but also highlighted the difficulty of accounting for timing effects of water deficit where second flushes of pods alter canopy development, biomass and yield accumulation, and N dynamics. Crown Copyright (C) 2003 Published by Elsevier B.V. All rights reserved.

Localization and movement of mineral oil in plants by fluorescence and confocal microscopy

Fluorescence and confocal laser scanning microscopy were explored to investigate the movement and localization of mineral oils in citrus. In a laboratory experiment, fluorescence microscopy observation indicated that when a 'narrow' distillation fraction of an nC23 horticultural mineral oil was applied to adaxial and opposing abaxial leaf surfaces of potted orange [Citrus x aurantium L. (Sapindales: Rutaceae)] trees, oil penetrated steadily into treated leaves and, subsequently, moved to untreated petioles of the leaves and adjacent untreated stems. In another experiment, confocal laser scanning microscopy was used to visualize the penetration into, and the subsequent cellular distribution of, an nC24 agricultural mineral oil in C. trifoliata L. seedlings. Oil droplets penetrated or diffused into plants via both stomata and the cuticle of leaves and stems, and then moved within intercellular spaces and into various cells including phloem and xylem. Oil accumulated in droplets in intercellular spaces and within cells near the cell membrane. Oil entered cells without visibly damaging membranes or causing cell death. In a field experiment with mature orange trees, droplets of an nC23 horticultural mineral oil were observed, by fluorescence microscopy, in phloem sieve elements in spring flush growth produced 4-5 months and 16-17 months after the trees were sprayed with oil. These results suggest that movement of mineral oil in plants is both apoplastic via intercellular spaces and symplastic via plasmodesmata. The putative pattern of the translocation of mineral oil in plants and its relevance to oil-induced chronic phytotoxicity are discussed.

Control of ion transport in mammalian airways by protease activated receptors type 2 (PAR-2)

Protease-activated receptors (PARs) are widely distributed in human airways. They couple to G-proteins and are activated after proteolytic cleavage of the N terminus of the receptor. Evidence is growing that PAR subtype 2 plays a pivotal role in inflammatory airway diseases, such as allergic asthma or bronchitis. However, nothing is known about the effects of PAR-2 on electrolyte transport in the native airways. PAR-2 is expressed in airway epithelial cells, where they are activated by mast cell tryptase, neutrophil proteinase 3, or trypsin. Recent studies produced conflicting results about the functional consequence of PAR-2 stimulation. Here we report that stimulation of PAR-2 receptors in mouse and human airways leads to a change in electrolyte transport and a shift from absorption to secretion. Although PAR-2 appears to be expressed on both sides of the epithelium, only basolateral stimulation results in inhibition of amiloride sensitive Na+ conductance and stimulation of both luminal Cl- channels and basolateral K+ channels. The present data indicate that these changes occur through activation of phospholipase C and increase in intracellular Ca2+, which activates basolateral SK4 K+ channels and luminal Ca2+-dependent Cl- channels. In addition, the present data suggest a PAR-2 mediated release of prostaglandin E2, which may contribute to the secretory response. In conclusion, these results provide further evidence for a role of PAR-2 in inflammatory airway disease: stimulation of these receptors may cause accumulation of airway surface liquid, which, however, may help to flush noxious stimuli away from the affected airways. ©2005 FASEB

Effects of Variation at the ALDH2 Locus on Alcohol Metabolism, Sensitivity, Consumption, and Dependence in Europeans

Background: The low-activity variant of the aldehyde dehydrogenase 2 (ALDH2) gene found in East Asian populations leads to the alcohol flush reaction and reduces alcohol consumption and risk of alcohol dependence (AD). We have tested whether other polymorphisms in the ALDH2 gene have similar effects in people of European ancestry. Methods: Serial measurements of blood and breath alcohol, subjective intoxication, body sway, skin temperature, blood pressure, and pulse were obtained in 412 twins who took part in an alcohol challenge study. Participants provided data on alcohol reactions, alcohol consumption, and symptoms related to AD at the time of the study and subsequently. Haplotypes based on 5 single-nucleotide polymorphisms (SNPs) were used in tests of the effects of variation in the ALDH2 gene on alcohol metabolism and alcohol's effects. Results: The typed SNPs were in strong linkage disequilibrium and 2 complementary haplotypes comprised 83% of those observed. Significant effects of ALDH2 haplotype were observed for breath alcohol concentration, with similar but smaller and nonsignificant effects on blood alcohol. Haplotype-related variation in responses to alcohol, and reported alcohol consumption, was small and not consistently in the direction predicted by the effects on alcohol concentrations. Conclusions: Genetic variation in ALDH2 affects alcohol metabolism in Europeans. However, the data do not support the hypothesis that this leads to effects on alcohol sensitivity, consumption, or risk of dependence.

Respiration by buried echidnas Tachyglossus aculeatus

Short-beaked echidnas have an impressive ability to submerge completely into soil or sand and remain there, cryptic, for long periods. This poses questions about how they manage their respiration, cut off from a free flow of gases. We measured the gradient in oxygen partial pressure (P-O2) away from the snouts of buried echidnas and oxygen consumption (V-O2) in five individuals under similar conditions, in two substrates with different air-filled porosities (f(a)). A theoretical diffusion model indicated that diffusion alone was insufficient to account for the flux of oxygen required to meet measured rates of V-O2. However, it was noticed that echidnas often showed periodic movements of the anterior part of the body, as if such movements were a deliberate effort to flush the tidal air space surrounding their nostrils. These 'flushing movements' were subsequently found to temporarily increase the levels of interstitial oxygen in the soil around the head region. Flushing movements were more frequent while V-O2 was higher during the burrowing process, and also in substrate with lower fa. We conclude that oxygen supply to buried echidnas is maintained by diffusion through the soil augmented by periodic flushing movements, which ventilate the tidal airspace that surrounds the nostrils.

The antimicrobial efficacy of copper alloy furnishing in the clinical environment:a crossover study

Objective. To determine whether copper incorporated into hospital ward furnishings and equipment can reduce their surface microbial load. Design. A crossover study. Setting. Acute care medical ward with 19 beds at a large university hospital. Methods. Fourteen types of frequent-touch items made of copper alloy were installed in various locations on an acute care medical ward. These included door handles and push plates, toilet seats and flush handles, grab rails, light switches and pull cord toggles, sockets, overbed tables, dressing trolleys, commodes, taps, and sink fittings. Their surfaces and those of equivalent standard items on the same ward were sampled once weekly for 24 weeks. The copper and standard items were switched over after 12 weeks of sampling to reduce bias in usage patterns. The total aerobic microbial counts and the presence of indicator microorganisms were determined. Results. Eight of the 14 copper item types had microbial counts on their surfaces that were significantly lower than counts on standard materials. The other 6 copper item types had reduced microbial numbers on their surfaces, compared with microbial counts on standard items, but the reduction did not reach statistical significance. Indicator microorganisms were recovered from both types of surfaces; however, significantly fewer copper surfaces were contaminated with vancomycin-resistant enterococci, methicillin-susceptible Staphylococcus aureus, and coliforms, compared with standard surfaces. Conclusions. Copper alloys (greater than or equal to 58% copper), when incorporated into various hospital furnishings and fittings, reduce the surface microorganisms. The use of copper in combination with optimal infection-prevention strategies may therefore further reduce the risk that patients will acquire infection in healthcare environments.

Modelagem da poluição difusa em uma bacia de drenagem urbana

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES

Morfometria dos forames mandibular, mentual e infraorbital de Lobo-guará Chrysocyon brachyurus, Illiger, 1815 aplicada a bloqueios anestésicos

CHAPTER II - The Chrysocyon brachyurus is the biggest South American canid which has a high frequency of dental injuries, both in wild and captivity. Thus, veterinary procedures are necessary to preserve the feeding capacity of hundreds of captive specimens worldwide. The aim of this study was to study the mandibular morphometry of maned wolf with emphasis on the establishment of anatomic references to the anesthetic blockage of the inferior alveolar and mental nerves. Therefore, 15 measurements in 22 hemimandibles of C. brachyurus adults were taken. For extra-oral technique of blockage of the inferior alveolar nerve at the level of the mandibular foramen, it is stated that the needle should be advanced, close to the medial surface of the mandibular ramus, by 11.4 mm perpendiculary from the palpable concavity. Alternatively, the needle can be introduced for 30.4 mm from the angular process at 20-25 degrees angle with the ventral margin. For blocking only the mentual nerve, it is recommended the introduction of needle for 10 mm, close to the lateral aspect of the mandibular body, at the level of the lower first premolar. The mandibular foramen showed similars position, size and symmetry in the maned wolfs specimens examined. The comparison of the data with those available for other carnivores reflects the necessity for determining these anatomical references specifically for each species.

Growth and yield of red raspberries cultivated under open field condition vs. high tunnel or rain shelter in the northern canadian climate

La culture sous abris avec des infrastructures de type grands tunnels est une nouvelle technologie permettant d’améliorer la production de framboises rouges sous des climats nordiques. L’objectif principal de ce projet de doctorat était d’étudier les performances de ces technologies (grands tunnels vs. abris parapluie de type Voen, en comparaison à la culture en plein champ) et leur effets sur le microclimat, la photosynthèse, la croissance des plantes et le rendement en fruits pour les deux types de framboisiers non-remontants et remontants (Rubus idaeus, L.). Puisque les pratiques culturales doivent être adaptées aux différents environnements de culture, la taille d’été (pour le cultivar non-remontant), l’optimisation de la densité des tiges (pour le cultivar remontant) et l’utilisation de bâches réfléchissantes (pour les deux types des framboisiers) ont été étudiées sous grands tunnels, abris Voen vs. en plein champ. Les plants cultivés sous grands tunnels produisent en moyenne 1,2 et 1,5 fois le rendement en fruits commercialisables que ceux cultivés sous abri Voen pour le cv. non-remontant ‘Jeanne d’Orléans’ et le cv. remontant ‘Polka’, respectivement. Comparativement aux framboisiers cultivés aux champs, le rendement en fruits des plants sous grands tunnels était plus du double pour le cv. ‘Jeanne d’Orléans’ et près du triple pour le cv. ‘Polka’. L’utilisation de bâches réfléchissantes a entrainé un gain significatif sur le rendement en fruits de 12% pour le cv. ‘Jeanne d’Orléans’ et de 17% pour le cv. ‘Polka’. La taille des premières ou deuxièmes pousses a significativement amélioré le rendement en fruits du cv. ‘Jeanne d’Orléans’ de 26% en moyenne par rapport aux framboisiers non taillés. Des augmentations significatives du rendement en fruits de 43% et 71% du cv. ‘Polka’ ont été mesurées avec l’accroissement de la densité à 4 et 6 tiges par pot respectivement, comparativement à deux tiges par pot. Au cours de la période de fructification du cv. ‘Jeanne d’Orléans’, les bâches réfléchissantes ont augmenté significativement la densité de flux photonique photosynthétique (DFPP) réfléchie à la canopée inférieure de 80% en plein champ et de 60% sous grands tunnels, comparativement à seulement 14% sous abri Voen. Durant la saison de fructification du cv. ‘Polka’, un effet positif de bâches sur la lumière réfléchie (jusqu’à 42%) a été mesuré seulement en plein champ. Dans tous les cas, les bâches réfléchissantes n’ont présenté aucun effet significatif sur la DFPP incidente foliaire totale et la photosynthèse. Pour le cv. ‘Jeanne d’Orléans’, la DFPP incidente sur la feuille a été atténuée d’environ 46% sous le deux types de revêtement par rapport au plein champ. Par conséquent, la photosynthèse a été réduite en moyenne de 43% sous grands tunnels et de 17% sous abris Voen. Des effets similaires ont été mesurés pour la DFPP incidente et la photosynthèse avec le cv. Polka. En dépit du taux de photosynthèse des feuilles individuelles systématiquement inférieur à ceux mesurés pour les plants cultivés aux champs, la photosynthèse de la plante entière sous grands tunnels était de 51% supérieure à celle observée au champ pour le cv. ‘Jeanne d’Orléans’, et 46% plus élevée pour le cv. ‘Polka’. Ces résultats s’expliquent par une plus grande (près du double) surface foliaire pour les plants cultivés sous tunnels, qui a compensé pour le plus faible taux de photosynthèse par unité de surface foliaire. Les températures supra-optimales des feuilles mesurées sous grands tunnels (6.6°C plus élevé en moyenne que dans le champ), ainsi que l’atténuation de la DFPP incidente (env. 43%) par les revêtements de tunnels ont contribué à réduire le taux de photosynthèse par unité de surface foliaire. La photosynthèse de la canopée entière était étroitement corrélée avec le rendement en fruits pour les deux types de framboisiers rouges cultivés sous grands tunnels ou en plein champ.

Investigation expérimentale du décollement dans l’aspirateur d’une turbine bulbe

La présente thèse propose une étude expérimentale du décollement dans le diffuseur d’un modèle de turbine hydroélectrique bulbe. Le décollement se produit quand la turbine est opérée à forte charge et il réduit la section effective de récupération du diffuseur. La diminution de la performance du diffuseur à forte charge engendre une baisse brusque de l’efficacité de la turbine et de la puissance extraite. Le modèle réduit de bulbe est fidèle aux machines modernes avec un diffuseur particulièrement divergent. Les performances de la turbine sont mesurées sur une large gamme de points d’opération pour déterminer les conditions les plus intéressantes pour l’étude du décollement et pour étudier la distribution paramétrique de ce phénomène. La pression est mesurée le long de l’aspirateur par des capteurs dynamiques affleurants alors que les champs de vitesse dans la zone de décollement sont mesurés avec une méthode PIV à deux composantes. Les observations à la paroi sont pour leur part faites à l’aide de brins de laine. Pour un débit suffisant, le gradient de pression adverse induit par la géométrie du diffuseur affaiblit suffisamment la couche limite, entraînant ainsi l’éjection de fluide de la paroi le long d’une large enveloppe tridimensionelle. Le décollement instationnaire tridimensionnel se situe dans la même zone du diffuseur indépendamment du point d’opération. L’augmentation du débit provoque à la fois une extension de la zone de décollement et une augmentation de l’occurrence de ses manifestations. La position et la forme du front de décollement fluctue significativement sans périodicité. L’analyse topologique et celle des tourbillons des champs de vitesse instantanés montrent une topologie du front de décollement complexe qui diffère beaucoup d’une réalisation à l’autre. Bien que l’écoulement soit turbulent, les tourbillons associés aux foyers du front sont clairement plus gros et plus intenses que ceux de la turbulence. Cela suggère que le mécanisme d’enroulement menant aux tourbillons du décollement est clairement distinct des mécanismes de la turbulence.

Desenvolvimento e crescimento da espécie de cogumelo Pleurotus ostreatus em garrafas de plástico reutilizado

Dissertação de Mestrado, Tecnologia e Segurança Alimentar, 22 de Junho de 2016, Universidade dos Açores.

Moedor de Pixels : interfaces, interações e audiovisual

Dissertação (mestrado)—Universidade de Brasília, Instituto de Artes, Programa de Pós-Graduação em Arte, 2016.

Rastreio parasitológico de Tritrichomonas foetus em gatos

Dissertação de Mestrado Integrado em Medicina Veterinária