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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.
51

Florística, aspectos ecológicos e conservação das pteridófitas ocorrentes no Parque Ecológico João Vasconcelos Sobrinho (Caruaru-Pernambuco-Brasil)

XAVIER, Sergio Romero da Silva January 2003 (has links)
Made available in DSpace on 2014-06-12T15:05:02Z (GMT). No. of bitstreams: 2 arquivo4633_1.pdf: 940172 bytes, checksum: 6dc41c9e65865c47b206b8fc8bcce9f1 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2003 / Foi realizado o levantamento florístico e análise dos aspectos ecológicos das pteridófitas ocorrentes no Parque Ecológico João Vasconcelos Sobrinho (PEJVS), também conhecido como Brejo dos Cavalos, caracteristicamente uma área de floresta serrana ou brejo de altitude no município de Caruaru, em Pernambuco. O Estado detém poucos remanescentes deste tipo de floresta, que são verdadeiros refúgios biológicos para inúmeras espécies de pteridófitas. No período de um ano, foram realizadas seis excursões bimestrais, bem como levantamentos das espécies depositadas nos herbários existentes no Estado, encontrando uma diversidade de 76 espécies distribuídas em 32 gêneros e 15 famílias, sendo a família Pteridaceae a mais representativa na área, além de ocorrer predominância de espécies herbáceas, hemicriptófitas, terrícolas, ciófilas e de interior de mata. O baixo índice de espécies epífitas, a alta representatividade do gênero Adiantum L. e o significativo número de espécies inventariadas somente em Herbário, refletem o caráter secundário das matas do PEJVS e evidenciam uma provável pteridoflora outrora mais rica
52

High Altitude Platform Networks (HAPNETs): Design, Deployment, and Resource Management

Tsai, Ming-Cheng 04 1900 (has links)
In this thesis, we consider maximized power allocation of non-orthogonal multiple ac- cess (NOMA) schemes since it outperforms than orthogonal multiple access (OMA) for the high altitude platform networks (HAPNETs) both in the back- haul and access links. Secondly, we propose a cluster formation (CF) algorithm and power-bandwidth resource allocation (PB-RA) for solving the resource management of HAPNETs. We adopt the particle swarm optimization (PSO) algorithm to explore the optimal de- ployment of high altitude platforms (HAPs) and unmanned aerial vehicles (UAVs) iteratively by a given swarm size. By PSO, we provide the best deployment under a given iteration number. Besides that, numerical results show that the NOMA schemes have better performance than OMA ones concerning different network control factors like the number of BSs, HAPs, and UAVs.
53

Re: "Mortality Attributed to COVID-19 in High-Altitude Populations" by Woolcott and Bergman

Zubieta-Calleja, Gustavo, Merino-Luna, Alfredo, Zubieta-Deurioste, Natalia, Armijo-Subieta, N. Freddy, Soliz, Jorge, Arias-Reyes, Christian, Escalante-Kanashiro, Raffo, Carmona-Suazo, Jose Antonio, López-Bascope, Alberto, Calle-Aracena, Jose Manuel, Epstein, Murray, Maravi, Enrique 01 March 2021 (has links)
Carta al editor / Revisión por pares
54

THE EFFECT OF ALTITUDE EXPOSURE: VIA REBREATHING ON INTERVAL PERFORMANCE

Baldwin, Chris 15 August 2011 (has links)
No description available.
55

Is Hypoxic (Altitude) Training More Effective than Sea Level Training for Competition at Sea Level?

Melissa, Lori 08 1900 (has links)
The purpose of the present study was to determine whether or not the combination of normobaric hypoxia and exercise training would enhance adaptations in skeletal muscle over and above that which occurs with the same amount of training under normoxic conditions. Also investigated was the effect of such training conditions on performance as assessed by V0_2max and maximal aerobic capacity (MAC). Ten males performed unilateral cycle ergometry training 3 times per week for 8 weeks so that one leg was trained under normoxic conditions and the other while breathing an hypoxic gas mixture (FI0_2= 13.5%; equivalent to an altitude of 3,292 meters). Absolute power output was kept constant for both conditions and subjects performed both continuous (75% pre-training maximal power output) and interval (100% pre-training maximal power output) training. Needle biopsies were taken from the vastus lateralis of both legs to assess pre- and post-training differences in morphometric and biochemical data. Performance measures included V0_2max and MAC (time to fatigue at 95% pre-training maximal power output) for each leg. Significant increases in V0_2max (p <0.05) occurred in both legs with higher peak ventilation and blood lactate concentrations (p <0.05) post-training. Marked improvements (p <0.05) in MAC were also seen with an increase of 402% in the normoxically-trained leg and 513% in the hypoxically-trained leg. Citrate synthase (CS), succinate dehydrogenase, and phosphofructokinase activity was significantly (p <0.05) higher in both legs following training with a significantly greater (p <0.05) increase in CS in the hypoxically-trained leg. There were no differences in capillary/fiber ratio, capillary density, fiber area, fiber type, and mitochondrial volume density for either condition, pre- or post-training. It is concluded that hypoxia enhanced the muscle oxidative capacity (as marked by cs activity) but was unable to improve performance over and above that which occurs with the same training at sea level. / Thesis / Master of Science (MS)
56

Comparison of simulated high altitude pilot effective performance time between habitual smokers and non smokers

Fletcher, James F. 01 April 2003 (has links)
No description available.
57

Food-based strategies to enhance iron and zinc bioavailability of complementary foods consumed by young children in Ethiopia / Voies alimentaires d’amélioration de la biodisponibilité du fer et du zinc dans les aliments de complément consommés par les jeunes enfants en Ethiopie

Baye Yimam, Kaleab 05 April 2013 (has links)
Voies alimentaires d'amélioration de la biodisponibilité du fer et du zinc dans les aliments de complément consommés par les jeunes enfants en Ethiopie. Le retard de croissance et les carences en micronutriments sont largement répandus dans les pays en développement tels que l'Ethiopie et atteignent un pic pendant la période d'alimentation complémentaire. L'adéquation des pratiques d'alimentation complémentaire du jeune enfant a été évaluée par rappel de 24h auprès de 76 ménages dans la région nord du Wollo, au nord de l'Ethiopie. Plusieurs pratiques d'alimentation n'étaient pas en accord avec les recommandations internationales WHO/PAHO. Les aliments les plus fréquemment consommés étaient l'injera –une sorte de galette à base de céréales fermentées- accompagnée de sauces à base de légumineuses, et le pain. Les procédés de transformation traditionnels de ces aliments ont été observés sur le terrain. Différents mélanges de céréales étaient utilisés pour la préparation de l'injera. Le type de mélange conditionne la cinétique de fermentation, qui à son tour, affecte l'hydrolyse de l'acide phytique. Même lorsque la dégradation de l'acide phytique était supérieure à 95%, la bioaccessibilité du fer et le pourcentage d'absorption calculé par algorithme n'étaient pas améliorés, alors que les ratios molaires phytate:Fe étaient optimaux (<0.4). D'autres inhibiteurs d'absorption semblent jouer un rôle important. A cet égard, les effets relatifs des phytates, polyphénols et fibres sur la bioaccessibilité du fer ont été évalués par une approche mécanistique utilisant des enzymes exogènes. Dans les farines utilisées pour la préparation de l'injera, la déphytinisation suivie de l'hydrolyse des fibres et/ou l'oxydation des polyphénols permet une augmentation de la bioaccessibilité du fer plus importante que la seule déphytinisation. La réponse aux traitements enzymatiques ainsi que l'importance relative des différents inhibiteurs d'absorption étaient dépendantes de la matrice alimentaire. L'optimisation des procédés traditionnels de transformation en vue de favoriser la dégradation des phytates, des polyphénols chélateurs de fer et des fibres pourrait améliorer significativement la biodisponibilité du fer dans les injeras. Des interventions visant à promouvoir les bonnes pratiques d'alimentation complémentaires recommandées par l'OMS sont nécessaires dans les régions enquêtées. Mots-clés: Phytate, polyphénols, fibres, altitude, micronutriments, bioaccessibilité / Food-based strategies to enhance iron and zinc bioavailability of complementary foods consumed by young children in EthiopiaStunting and micronutrient deficiencies are widespread in developing countries like Ethiopia and reach their peak during the period of complementary feeding. The adequacy of complementary feeding practices of young children in north Wollo, northern Ethiopia was evaluated in 76 households using two 24h recalls. Several feeding practices were not in accordance with WHO/PAHO recommendations. The most frequently consumed foods were legume-based stews, bread, and injera- a fermented cereal-based pancake. Traditional processing of these foods was observed in-field. Different cereal blends were used in injera preparation and this influenced the fermentation kinetics which in turn affected phytic acid hydrolysis. Even when phytic acid degradation was >95%, iron bioaccessibility and algorithm predicted absorption were not improved, despite ideal phytate:Fe molar ratios (<0.4). This suggested an important role of other absorption inhibitors. In this regard, the relative effect of phytate, polyphenols, and fibers on iron bioaccessibility was evaluated by making use of a mechanistic approach that involved the application of exogenous enzymes. In injera flours, dephytinization followed by hydrolysis of fibers and, or oxidation of polyphenols, resulted in higher iron bioaccessibility than dephytinization alone. The relative importance of mineral absorption inhibitors as well as the response to enzymatic treatments was dependent on the food matrix. If possible, optimization of household food processing for greater decrease in phytate, iron-binding polyphenols and fibers may be needed to significantly improve iron bioavailability in injeras. Interventions promoting the WHO guiding principles for complementary feeding practices and behaviors are recommended. Keywords: Phytate, polyphenols, fibers, altitude, micronutrients, bioaccessibility
58

Influência do hidroperíodo no banco de propágulos dormentes de invertebrados aquáticos em áreas úmidas de altitude no Sul do Brasil

Wüsth, Regiane 28 July 2014 (has links)
Submitted by Fabricia Fialho Reginato (fabriciar) on 2015-08-28T00:06:02Z No. of bitstreams: 1 RegianeWusth.pdf: 725429 bytes, checksum: e20257e94144c76e5a69704462ec15a8 (MD5) / Made available in DSpace on 2015-08-28T00:06:02Z (GMT). No. of bitstreams: 1 RegianeWusth.pdf: 725429 bytes, checksum: e20257e94144c76e5a69704462ec15a8 (MD5) Previous issue date: 2014 / Nenhuma / As áreas úmidas estão entre os ecossistemas que mais contribuem para a diversidade biológica. Por outro lado, também são considerados os ecossistemas mais ameaçados pela ação humana. As áreas úmidas intermitentes são definidas pelo seu hidroperíodo, caracterizado pelo número de meses em que esses ecossistemas apresentam água superficial durante um ano. O hidroperíodo é um fator importante que influencia as comunidades de invertebrados em áreas úmidas, afetando diretamente as espécies que necessitam completar parte ou todo o seu ciclo de vida na água. Em áreas úmidas intermitentes, espécies de invertebrados aquáticos produzem propágulos dormentes capazes de resistir à dessecação, constituindo uma reserva ecológica e evolutiva fundamental em resposta às condições adversas relacionadas às flutuações no regime hidrológico e de outros fatores ambientais. O objetivo geral desse estudo foi analisar a emergência de invertebrados aquáticos via bancos de propágulos dormentes em sedimentos secos de áreas úmidas intermitentes de altitude no Sul do Brasil, relacionando as respostas da comunidade com diferentes hidroperíodos. Os objetivos específicos foram: 1) Comparar a riqueza, a abundância e a composição de invertebrados aquáticos emergentes de propágulos dormentes entre áreas úmidas que apresentam diferentes hidroperíodos, e 2) Identificar táxons de invertebrados aquáticos emergentes de propágulos dormentes que possam ser utilizados como indicadores de diferentes hidroperíodos de áreas úmidas de altitude no Sul do Brasil. Foram realizadas coletas de sedimento seco em nove áreas úmidas distribuídas em três tratamentos de hidroperíodo (curto, médio e longo) localizadas nos Campos de Cima da Serra do Sul do Brasil, dentro do bioma Mata Atlântica. Em laboratório, o sedimento seco foi hidratado com água destilada e mantido sob temperatura e fotoperíodo controlados. Os invertebrados foram amostrados no dia posterior à hidratação, e semanalmente durante 10 semanas. Um total de 19.868 indivíduos distribuídos em 11 táxons foi encontrado ao longo do experimento. A riqueza, a abundância e a composição de invertebrados aquáticos não variaram entre os diferentes hidroperíodos. Entretanto, Karualona muelleri foi mais abundante nas áreas úmidas com hidroperíodos curto e médio e Kurzia polyspina foi mais abundante nas áreas úmidas com hidroperíodo longo. Os tardígrados foram abundantes em áreas com hidroperíodo médio. Nosso estudo demonstrou que as áreas úmidas de altitude estudadas podem ser facilmente recolonizadas após um período de seca e que as comunidades dormentes de invertebrados aquáticos são fundamentais no processo de sucessão ecológica nesses importantes ecossistemas do Sul do Brasil. / The wetlands are among the ecosystems that contribute the most to biological diversity. On the other hand, are also considered the most threatened ecosystems by human action. The intermittent wetlands are defined by its hydroperiod, characterized by the number of months in which those present surface water during a year. The hydroperiod is an important factor to invertebrate communities in wetland systems, directly affecting the species that need to complete part or all of their life cycle in the water. In intermittent wetlands, species of aquatic invertebrates produce dormant propagules able to resist desiccation, constituting a fundamental evolutionary and ecological reserve in response to adverse conditions related to fluctuations in the hydrological regime and other environmental factors. The main objective of this study was to analyze the emergence of aquatic invertebrates via banks of dormant propagules in dry sediment of intermittent wetlands located in high altitudes in southern Brazil, relating the responses of the community with different hydroperiods. The specific objectives are: 1) Compare the richness, abundance and composition of drought-resistant aquatic invertebrates between wetlands that have different hydroperiods, and 2) Identify taxa of drought-resistant aquatic invertebrates which may be used as indicators of different hydroperiods in wetlands in southern Brazil. Sediment samplings were carried out in nine intermittent wetlands distributed in three treatments of hydroperiod (short, medium and long) located in southern Brazil, within the Atlantic forest biome. In the laboratory, the dry sediment was hydrated with distilled water and kept under controlled temperature and photoperiod. The invertebrates were sampled on the first day after hydration, and weekly for 10 weeks. A total of 19,868 individuals distributed in 11 taxa were found throughout the experiment. The richness, abundance and composition of aquatic invertebrates did not vary between the different hydroperiods. However, Karualona muelleri was more abundant in wetlands with short and medium hydroperiods and Kurzia polyspina, on the other hand, was most abundant in wetlands with long hydroperiod. The tardigrades were abundant in wetlands with medium hydroperiod. Our study showed that the studied wetlands can be easily recolonized after a dry period and that the drought-resistant aquatic invertebrate communities play a critical role in the ecological succession in southern Brazil wetlands.
59

Longitudinal control laws design for a flying wing aircraft

Zhu, Yan. 02 1900 (has links)
This research is concerned with the flight dynamic, pitch flight control and flying qualities assessment for the reference BWB aircraft. It aims to develop the longitudinal control laws which could satisfy the flying and handing qualities over the whole flight envelope with added consideration of centre of gravity (CG) variation. In order to achieve this goal, both the longitudinal stability augmentation system (SAS) and autopilot control laws are studied in this thesis. Using the pole placement method, two sets of local Linear-Time-Invariant (LTI) SAS controllers are designed from the viewpoints of flying and handing qualities assessment and wind disturbance checking. The global gain schedule is developed with the scheduling variable of dynamic pressure to transfer gains smoothly between these two trim points. In addition, the poles movement of short period mode with the varying CG position are analysed, and some approaches of control system design to address the problem of reduced stability induced by CG variation are discussed as well. To achieve the command control for the aircraft, outer loop autopilot both pitch attitude hold and altitude hold are implemented by using the root locus method. By the existing criteria in MIL-F-8785C specifications being employed to assess the augmented aircraft response, the SAS linear controller with automatic changing gains effectively improve the stability characteristic for the reference BWB aircraft over the whole envelope. Hence, the augmented aircraft equals to a good characteristic controlled object for the outer loop or command path design, which guarantee the satisfactory performance of command control for the BWB aircraft. The flight control law for the longitudinal was completed with the SAS controller and autopilot design. In particular, the SAS was achieved with Level 1 flying and handing qualities, meanwhile the autopilot system was applied to obtain a satisfactory pitch attitude and altitude tracking performance.
60

Herpetofauna do Planalto da Ibiapaba, Ceará: composição, aspectos reprodutivos, distribuição espaço-temporal e conservação

Loebmann, Daniel [UNESP] 02 July 2010 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:35:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-07-02Bitstream added on 2014-06-13T20:07:20Z : No. of bitstreams: 1 loebmann_d_dr_rcla.pdf: 4477659 bytes, checksum: 17d94b5d744cdd36754c31cd3144af79 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O Planalto da Ibiapaba é um dos mais importantes fragmentos de floresta úmida do Ceará. Localizado do extremo noroeste do estado, essa região é privilegiada não somente pelas áreas de florestas úmidas, mas também por um mosáico de ambientes ao longo de sua extensão. Consequentemente, a fauna de anfíbios e répteis é extremamente rica se comparada as outras áreas do Bioma Caatinga. Durante dois anos a herpetofauna desse refúgio da vida silvestre foi estudada e os resultados obtidos são apresentados nessa tese. As 121 espécies (38 anfíbios e 83 répteis) encontradas no presente estudo revelam um resultado bastante expressivo, não só pelo fato de ser esta a região com maior riqueza de espécies para o Bioma Caatinga conhecidada até o momento, mas também pelo fato de que o Planalto da Ibiabapa abriga espécies consideradas raras e/ou ameaçadas. Padrões reprodutivos de machos e fêmeas em comunidades de anfíbios também foram investigados, tentando compreender melhor os mecanismos adaptativos das espécies para sobreviver às duras condições impostas pelo clima marcadamente sazonal da Caatinga. A presença no Planalto da Ibiapaba de Adelophryne baturitensis, uma espécie considerada ameaçada e até então conhecida somente para a localidade‐tipo, foi também estudada em maior detalhe e dados inéditos de vocalização, descobertas de novas populações e dados moleculares são apresentados. Ampliações de distribuição e atualizações de distribuição de 14 espécies são também apresentadas nessa tese. Os resultados obtidos mostram a necessidade de preservar os fragmentos de floresta úmida e regiões adjacentes do Planalto da Ibiapaba, além do que são importantes para uma melhor compreensão da ecologia, biogeografia e taxonomia dos anfíbios e répteis de florestas úmidas do Nordeste e de áreas abertas do Brasil, em especial do Bioma Caatinga / The Planalto da Ibiapaba is one of the most important fragments of moist forests in the state of Ceará. Located at the Northwestern portion of the state, this region is not only privileged by the presence of moist forest areas, but also by the presence of a mosaic of environments along its extension. Consequently, the fauna of amphibians and reptiles present there is extremely rich if compared to other areas from the Caatinga Biome. During two years the herpetofauna of this wildlife refuge was studied and the results are presented in this thesis. The 121 species (38 amphibians and 83 reptiles) encountered in this study reveal a very expressive result, not only due to the fact that this is the region with the highest species richness for the Caatinga Biome known so far, but also because Planalto da Ibiabapa shelters species considered rare and threatened. Reproductive patterns for males and females in amphibian communities were also investigated, in order to try to understand adaptive mechanisms of the amphibian species to survive the harsh conditions imposed by marked seasonal climate of the Caatinga. The presence in Planalto da Ibiapaba of Adelophryne baturitensis, a species considered endangered and previously known only to its type locality, was also studied in more detail and data from vocalization, discoveries of new populations, and molecular data are here presented. Distribution extensions and upgrades of distribution from 14 species are also presented in this thesis. The results show the need to preserve the moist forest fragments and adjacent areas of the Planalto da Ibiapaba and are also important for the better understanding of ecology, biogeography, and taxonomy of amphibians and reptiles in the moist forests from Northeastern and open areas of Brazil, especially in the Caatinga Biome

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