Insignificant diurnal variations make the reliance on thermal inertia to ameliorate the thermal discomfort in the hot humid region impossible. Natural ventilation, therefore, is not only important, but the velocity of air that gets into the living area is crucial. Various ways of creating negative pressure (a process of increasing the interior air speed) are examined. The performance of roof types with different horizontal openings in enhancing interior air movement was investigated in an open throat wind tunnel. The results indicate a significant difference in the interior air velocity with roof type A opening type 1 (see fig. 27 and fig. 28). The thesis explores other ways of creating climate adapted architecture in providing acceptable comfort level in the hot humid climate. Warm humid climates are defined, and data for one example (Lagos, Nigeria) are analysed. Comfort zones are established relative to the region being investigated and the methods of limiting interior heat gain are described. The effects of orientation, cross ventilation and material choice are discussed. / Master of Architecture

Wind shear negatively impacts tropical cyclone (TC) intensity by disrupting the TC vortex and introducing lower equivalent potential temperature (θe) air, weakening the core. However, the ocean, a source of heat, aids in replenishing low θe boundary layer air, mitigating shear-induced ventilation effects. Favorable oceanic conditions, like higher sea-surface temperatures (SST), prevail in storm-relative motion quadrants not yet influenced by the TC. The interaction between storm-relative (e.g., SST) and shear-relative (e.g., ventilation) frameworks remains unclear. I propose an optimal overlap of shear-relative and motion-relative storm quadrants, where shear-induced weakening is minimized due to enhanced boundary layer recovery in a favorable ocean environment. This study presents a novel dataset comprising of co-located aircraft expendable bathythermographs (AXBT) and dropsondes from TROPIC and TC-DROPS datasets. Statistical analyses reveal air-sea correlations that cause up-shear and front-storm quadrant overlaps to be most beneficial to TC health, with investigation into the physical mechanisms driving these relationships.

BACKGROUND: Chagas disease, a parasitic infection caused by Trypanosoma cruzi, is a neglected disease endemic to Latin America. Currently, approximately 6–7 million people worldwide are infected. Although Chagas disease is not considered endemic to the United States (US), official estimates put the number of cases at about 300,000 people. However, screening for Chagas disease is not common in the US. This project assessed the barriers, challenges, and opportunities to implementing screening for Chagas disease in primary care settings. METHODS: This project consisted of: 1) a literature review comparing and contrasting Chagas disease screening programs in endemic and non-endemic countries, and 2) semi-structured individual and group interviews with 43 healthcare providers (HCPs) who care for patients at-risk for Chagas disease. Interviews included questions around feasibility of implementing Chagas disease screening in their professional settings and probed on preferences for professional education such as format, length, and mode. Interviews were carried out between April 2021 and January 2022. RESULTS: According to the literature review, no single program for Chagas disease screening works perfectly. However, analyzing both endemic and non-endemic country programs revealed successful components that could be applied to the US context. From the interviews, the majority of participants reported knowing little about Chagas disease, matching the current literature. Most HCPs interviewed were interested in incorporating screening for Chagas disease into their practice but had some concerns. For example, HCPs are already required to screen for several diseases so Chagas disease screening would need to be incorporated into existing workflows. Finally, many HCPs reported that official guidelines from the Centers for Disease Control and Prevention or professional organizations would be enough for them to begin screening. The results informed the creation of a handbook for implementing Chagas disease screening. CONCLUSION: There are many barriers and challenges to implementing routine screening for Chagas disease in primary care settings in the US. However, there is also interest among HCPs in learning more and addressing the gap in screening. Advocacy is also needed to address the lack of national and professional guidelines around screening for Chagas disease.

<p> Over the last two decades, mycoflorostic studies undertaken in Guyanese forests have uncovered hundreds of new fungal species and genera. One of the recovered fungal families was the Xylariaceae, although most were not identified to species. Members of this family play ecological roles as decomposers, endophytes, and pathogens of vascular plants and grass species.  In addition, this group is increasingly recognized as a significant source of novel metabolic products with potential for applications in medicine, agriculture, and industrial biofuel. Given its  potential, we took a more targeted approach to the documentation of this group. Our sampling  efforts drawing on more than two decades of field collections yielded ca. 90 species in 12 genera, including a putative pathogen, Xylaria karyophthora of the seeds of Chlorocardium spp (Greenheart). Despite the significance of Greenheart to the Guyanese economy, little is known  about the biology and ecology of this fungus. Due to the lack of available resources to study this  fungus, our objectives were two-fold: first, to sequence and annotate the genome of X.  karyophthora to provide a resource for genome-centric explorations, and to use this genome to  infer the biology and ecology of this fungus. We focused on identifying and characterizing  secretomes, viz. carbohydrate-active enzymes (CAZymes) and secondary metabolites  biosynthetic gene clusters (SMBGCs) to infer the nutritional strategy of this fungus. Our results  suggest that X. karyophthora has the capacity to act as both an endophyte and a pathogen. To  make further inferences about the population, we used SSR markers to elucidate the genetic  diversity and population structure of X. karyophthora. X. karyophthora populations have high  genetic diversity, potentially exploiting both outcrossing and inbreeding reproductive strategies, and demonstrate a pattern consistent with human-mediated spread. This work will contribute  information on new species and records of Xylariaceous fungi and their allies from Guyana with  particular emphasis on unraveling the epidemiology, genetic diversity, and population structure  of X. karyophthora </p>

Yes / In this work, we describe the genome of Lysinibacillus sp. strain A1, which was isolated from tropical soil. Analysis of its genome sequence shows the presence of a gene encoding for a putative peptidase responsible for nitrogen compounds. / UM High Impact Research Grants (UMMOHE HIR Grant UM C/625/1/HIR/MOHE/CHAN/01, no. A000001- 50001; UM-MOHE HIR Grant UM C/625/1/HIR/MOHE/CHAN/14/1, no. H-50001-A000027)

China's forest product imports have surged over the past two decades, fueled by robust economic growth and an inadequate domestic timber supply. In 2017, China implemented a complete logging ban in its natural forests, further widening the domestic timber supply gap. Many observers highlight the large and expanding trade volume as a significant driver of deforestation and forest degradation, especially in tropical regions. This research investigates the relationship between China's imports of wood-based forest products and tropical forest loss (deforestation), as well as the impacts of China's complete logging ban in natural forests in shaping this relationship. I found that the logging ban has contributed China's timber imports from both provincial-level and supplying countries' analyses. However, economic development, wood products exports, and forest endowment have also played important roles. I found a positive relationship between China's imports of wood-based forest products and the forest loss across all tropical countries, except in Latin America. Additionally, land conversion to agricultural production and pasture for livestock, and rural population are important drivers of the tropical forest loss. The analysis results provide insight into the complex policy, environmental, and economic factors influencing China's imports and tropical forest loss. This research offers valuable guidance for the Chinese government in crafting balanced policies that protect domestic forests while addressing tropical deforestation. / Doctor of Philosophy / For more than 20 years, China's demand for wood products has grown fast, driven by rapid economic growth and the country's limited timber supply. To protect its forests and environment, China banned tree cutting in its natural forests in 2017, further increasing the need for imported timber. This growing demand has been blamed to link to forest loss, especially in tropical areas. This study looks at the connection between China's wood imports and the loss of tropical forests. It also examines how the tree cutting ban in China has impacted this relationship. The findings show that the ban has led to an increase in timber imports. However, economic growth, wood products exports, and the availability of forests in China are also important factors. The study found that China's wood products imports are associated with forest loss in most tropical regions, except for Latin America. Additionally, converting land use from forests to crop production and raising livestock, and population growth in rural areas are key drivers of forest loss. These results offer insights that can help the Chinese government makes policies to protect both domestic and tropical forests.

A projective plane tropical curve is a proper immersion of a graph into the real Cartesian plane subject to some conditions such as that the images of all the edges must be lines with rational slopes. Two important combinatorial invariants of a projective plane tropical curve are its degree, d, and genus g. First, we explore Gathmann and Markwig's approach to the study of the moduli spaces of such curves and explain their proof that the number of projective plane tropical curves, counting multiplicity, passing through n = 3d + g -1 points does not depend on the choice of points, provided they are in tropical general position. This number of curves is called a Gromov-Written invariant. Second, we discuss the proof of a theorem of Mikhalkin that allows one to compute the Gromov-Written invariant by a purely combinatorial process of counting certain lattice paths.

The Kukkal basin, Tamil Nadu, India, receives most of its rain from the southwest monsoon (SWM). A sediment core from Kukkal Lake preserves a continuous sediment record from the early-Holocene to present (9000 yr BP to present). The present lake is situated at an elevation of similar to 1887m a.s.l., in a small basin that appears to have alternated between a and wetland depositional environment. Climate proxies, including sediment texture, total organic carbon (TOC), total nitrogen (TN), C/N, pollen and geochemical composition indicate a steady progression to wetter conditions, with two stepwise changes at about 8000, and between 3200 and 1800 yr BP. The change at 8000 yr BP appears to correspond to a brief (100-150years) dry spell recorded elsewhere in India. The change at 3200-1800 yr BP consisted in a rapid intensification of the SWM, and may correlate with the initiation of the Roman Warm Period'. There is no clear evidence of changes at the times of the Medieval Warm Period' (MWP') and the Little Ice Age' (LIA'). The C/N ratio of the sediments ranges from 14.02 to 8.31, indicating that the organic matter originated from a mixture of lacustrine algae, vascular and terrestrial plants. Chemical weathering indices (Chemical Index of Alteration (CIA), Chemical Index of Weathering (CIW), and Plagioclase Index of Alteration (PIA)) are consistent with extreme silicate weathering. Pollen data show a development from savanna vegetation prior to about 8000 yr BP, followed by grassland with palms, the appearance of ferns just prior to 3200 yr BP and the establishment of the tropical humid forest between 3200 and about 1800 yr BP.

Ce travail de thèse a pour but d'étudier la fixation d'azote marine dans les environnements riches mais déficitaires en azote (N), comparé au phosphore (P) dans un rapport N:P<16, grâce à l'utilisation d'approches complémentaire en culture in vitro et sur le terrain in situ. La première partie de ce travail a consisté à évaluer la réponse de la fixation d'azote de la cyanobactérie unicellulaire diazotrophe Crocosphaera watsonii face à des concentrations micromolaires en azote inorganique dissous (DIN) supposées inhiber l'activité de fixation d'azote : - suite à un apport sporadique, ou, - après une longue période d'acclimatation. Les résultats de ces études n'ont pas permis d'observer une inhibition des activités de fixation d'azote de cet organisme, laissant supposer que ce processus pourrait être actif dans une zone de l'Océan ayant ces même caractéristiques biogéochimiques : le Sud Est Tropical de l'Océan Pacifique (ETSP). En effet, cette zone est une des trois plus grandes zones de minimum d'oxygène (OMZ) de l'Océan et d'intenses processus de pertes de N (dénitrification et anammox) y ont lieu, résultant en un déficit de N par rapport au P. Des études présumaient que des processus inverses, de gains de N par la fixation d'azote, pourraient y être actifs mais aucune mesure à l'échelle du bassin n'y avait été faite car la fixation d'azote n'était supposée se produire que dans les environnements oligotrophes, comme les gyres subtropicaux. Dans le cadre d'un projet international, des missions océanographiques ont pu avoir lieu dans cette zone en Février 2010 pendant un évènement El Niño et en Mars-Avril 2011 pendant un évènement La Niña. / The objectif of these thesis was to study dinitrogen fixation in marine environments rich but deficient of nitrogen (N) compared to phosphorus (P) in a ratio N:P<16, by using complementary approaches in culture in vitro and in the field in situ. The first part of this work was to evaluate the response of nitrogen-fixing unicellular Cyanobacteria Crocosphaera watsonii faced with micromolar concentrations of dissolved inorganic nitrogen (DIN) supposed to inhibit nitrogen fixation activity : - after sporadic input, or, - after a long period of acclimatization. The results of these studies have failed to observe the inhibition of nitrogen fixation activities of this organism, suggesting that this process could be active in an area of the Ocean with these same biogeochemical characteristics : the Eastern Tropical South Pacific (ETSP). Indeed, this area is one of the three largest oxygen minimum zones (OMZ) of the Ocean, where intense processes of N losses (denitrification and anammox) took place, resulting in a deficit of N compared to P. Studies assumed that the inverse process, gain of N by nitrogen fixation, could be active in the ETSP but no measurements across the basin have been performed because nitrogen fixation was assumed to occur only in oligotrophic environments, such as the subtropical gyres. In the framework of an international project, cruises took place in this area in February 2010 during a El Niño event and in March-April 2011 during a La Niña event. Results of these two cruises have confirmed that nitrogen fixation was unexpectedly active with an intensity comparable to those reported in oligotrophic areas.

La vigueur initiale (accumulation de biomasse aérienne) est déterminante pour un rapide établissement de la culture et l'accès aux ressources, contribuant ainsi à un évitement du stress hydrique. Cette thèse vise à caractériser la diversité phénotypique chez le riz (Oriza Sativa.L) des traits constituant la vigueur initiale et sa plasticité sous stress hydrique. L'étude à démontrée que la vigueur initiale dépend de caractères relatifs aux forces de puits et à la demande en assimilats carbonés, tels que le taux de développement (DR), le tallage et la taille potentielle des feuilles. Une relation négative entre DR et la taille des feuilles a été observée et reliée à des différences d'utilisation des sucres par la plante au niveau des organes source et puits. En particulier des plantes à fort DR ont montré la tendance à stocker très peu d'amidon dans les feuilles source, inversement aux génotypes à grande feuilles. Sous stress hydrique des faibles tolérances à la sécheresse ont été liés à des réductions des activités des organes puits. Cette étude a montré l'existence d'une grande diversité génétique pour des trais liés à la tolérance au stress hydrique chez le riz. De plus des fortes réductions de croissance sous stress ont été observées pour les génotypes vigoureux. En effet de forts DR étaient aussi associés à une forte sensibilité du taux de transpiration foliaire (fermeture stomatique) et à une faible efficience d'utilisation de l'eau sous stress, de plus les génotypes à grandes feuilles ont montré un fort taux de sénescence foliaire. La diversité phénotypique observée dans le panel des riz Japonica est prometteuse pour des analyses génétiques d'association permettant l'amélioration de la tolérance au stress hydrique du riz ; cependant, les éventuelles limitations génétiques liées aux relations négatives observées entre vigueur initiale et tolérance au stress hydrique et donc, la facilité d'une co-sélection pour ces deux caractères complexes, devront être explorées. / Early vigour (ie.shoot biomass accumulation) is essential for rapid crop establishment, resource acquisition and can thus contribute to drought avoidance. This work aims at characterizing the diversity of component traits constituting early vigor and its plasticity under drought for rice (Oriza Sativa L.). This study demonstrated that sink dynamics: Developmental Rate (DR, inverse of phyllochron, in °C.d-1); tillering capacity and potential leaf size which together constitute incremental demand for assimilates are mayor drivers of early vigor. A tradeoff between DR and leaf size was explained by differences in carbon concentrations in source and sink leaves, in particular high DR genotypes stored low starch in source leaves compared to large leaf genotypes under well watered conditions. Low drought tolerance was related to a reduction in sink activity under drought. This study demonstrates that rice has a great genetic diversity in terms of drought tolerance. Under drought both high DR and large leaves vigorous genotypes had the strongest growth reduction. Indeed, DR was associated to high stomatal sensibility to drought and low WUE, while large leaves genotypes showed high leaf senescence rates. Finally, the phenotypic diversity observed within the studied japonica panel is promising for genetic association studies in order to improve rice drought resistance. The genetic limitations of the negative, phenotypic linkages observed between early vigor and drought tolerance, and thus the easiness to co-select for both traits will have to be explored.