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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.
391

Efeitos de um programa de treinamento que combina hidrogin?stica e treinamento resistido sobre as respostas hemodin?micas e metab?licas em idosos

Kura, Gustavo Graeff 19 May 2008 (has links)
Made available in DSpace on 2015-04-14T13:53:22Z (GMT). No. of bitstreams: 1 407241.pdf: 7162311 bytes, checksum: 0371f6fa53864cd7bddf22c241781bbb (MD5) Previous issue date: 2008-05-19 / Este estudo teve por objetivo verificar os efeitos da hidrogin?stica e do treinamento resistido combinado com a hidrogin?stica sobre as respostas hemodin?micas, metab?licas e de for?a muscular em idosos. Portanto, vinte e quatro idosos de ambos os sexos, saud?veis, praticantes de hidrogin?stica, foram divididos em dois grupos: grupo treinamento resistido combinado com hidrogin?stica n = 14 (TR + Hidro) e grupo hidrogin?stica n = 10 (Hidro). O estudo teve a dura??o de doze semanas, quando o grupo Hidro treinou uma vez na semana, e o grupo TR + Hidro treinou com exerc?cios de resist?ncia tr?s vezes na semana e hidrogin?stica uma vez na semana. As vari?veis metab?licas, hemodin?micas e de for?a muscular foram analisadas pela an?lise de vari?ncia (ANOVA) de dois caminhos 2x2 com medidas repetidas, a fim de verificar se havia intera??o entre os grupos (Hidro e TR + Hidro) ao longo do tempo (pr? e p?s-tratamento). O n?vel de signific?ncia utilizado neste estudo foi de 5% (p < 0,05). Ap?s as doze semanas de treinamento foi observada uma diferen?a significativa na intera??o grupo x tempo com rela??o ao limiar anaer?bio (Lan), demonstrando um comportamento diferenciado entre os grupos. As melhoras no Lan no grupo TR + Hidro variaram entre 20,3 e 26,37%; o grupo Hidro apresentou uma queda no Lan que variou entre -2,5 e -6,3%, dependendo da vari?vel utilizada para expressar o Lan. A for?a muscular em ambos os grupos apresentou um efeito estatisticamente significativo com rela??o ao tempo; as melhoras no pico de torque a 120?s variaram entre 5,83 e 12,60% no grupo Hidro e entre 11,22 e 17,88% no grupo TR + Hidro; as melhoras no pico de torque a 180?s variaram entre 5,58 e 13,58% no grupo Hidro e entre 8,02 e 16,25% no grupo TR + Hidro. Com rela??o ?s vari?veis hemodin?micas freq??ncia card?aca, press?o arterial sist?lica e duplo produto verificadas durante um teste subm?ximo de 10 minutos, ambas apresentaram uma diferen?a estatisticamente significativa com rela??o ao tempo, demonstrando que, a partir do minuto 2 at? o final do teste, essas vari?veis apresentaram valores menores do que os encontrados antes do treinamento. Os resultados obtidos no presente estudo demonstram que tanto a hidrogin?stica quanto o treinamento resistido combinado com a hidrogin?stica interferem positivamente nas respostas hemodin?micas, diminuindo o estresse cardiovascular durante o exerc?cio. Esses resultados podem ter sido influenciados pelo aumento na for?a muscular, uma vez que ambos os grupos apresentaram um aumento no pico de torque. Ainda, a melhora no Lan encontrada no grupo TR + Hidro pode ter sido influenciada diretamente pelo treinamento resistido, n?o pela hidrogin?stica, pelo fato de ter ocorrido somente no grupo que adicionou treinamento resistido
392

Développement épidémique de la fusariose des épis de blé et conséquences des intéractions entre espèces du complexe fusarien

Siou, Dorothée 14 January 2013 (has links) (PDF)
La fusariose de l'épi est une des maladies les plus importantes du blé. Elle est causée par un complexe d'espèces dont les plus courantes sont F. graminearum, F. culmorum, F. poae, M. majus et M. nivale. Ces champignons infectent les épis de blé au moment de la floraison mais l'impact de contaminations tardives sur les grains est peu compris. De plus, deux ou trois espèces sont susceptibles de co-infecter un même épi, ce qui pourrait modifier leur développement et leur production de toxines dans l'épi. Pour étudier ces problématiques, plusieurs isolats appartenant aux espèces citées ont été caractérisés selon leurs traits de vie et leur agressivité sur épi. Nous avons ensuite étudié le développement de souches de Fusarium inoculées 3 jours avant ou 0, 8, 18 ou 28 jours après la sortie des premières anthères. Les niveaux de maladie et toxines se sont révélés maximum autour de la floraison. La date d'inoculation semble conditionner la sévérité de la maladie et influencer le développement des souches. Des contaminations précoces et tardives seraient malgré tout possibles avec des isolats agressifs, ce qui ouvre la possibilité de telles infections au champ. Dans une deuxième expérimentation, nous avons étudié la compétition entre F. graminearum et les autres espèces (F. culmorum, F. poae, M. majus et M. nivale). Les réponses se sont avérées variables ; néanmoins, les souches agressives ne sont pas influencées ou légèrement favorisées par la présence d'un compétiteur alors que les souches peu agressives sont défavorisées par la présence de souches agressives. La production de toxines est, dans la plupart des cas, restée stable ou a diminué en co-inoculations par rapport aux inoculations simples. Dans une dernière expérimentation nous avons étudié la compétition entre souches associée à leurs mouvements dans l'épi. Inoculés seuls, les champignons progressent dans la totalité de l'épi alors que la présence d'un second champignon empêche leur développement, ce qui suggère une interaction compétitive entre eux. Cette étude apporte de nouveaux éléments nécessaires à la compréhension de l'épidémiologie de ces agents pathogènes et des niveaux de contamination à l'échelle du champ.
393

Análise Termodinâmica de um Buraco Negro com Monopolo Global em Teorias f(R)

Pereira, Francisco Bento Lustosa da Costa Duarte 26 May 2017 (has links)
Submitted by Biblioteca do Instituto de Física (bif@ndc.uff.br) on 2017-05-26T20:14:25Z No. of bitstreams: 1 TeseFranciscoLustosa.pdf: 726667 bytes, checksum: b1704d3cae6ec9a91da3b57f936bc53b (MD5) / Made available in DSpace on 2017-05-26T20:14:25Z (GMT). No. of bitstreams: 1 TeseFranciscoLustosa.pdf: 726667 bytes, checksum: b1704d3cae6ec9a91da3b57f936bc53b (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Neste trabalho estudamos o problema do Buraco Negro (BN) em um região contendo um Monopolo Global em uma teoria de gravidade f(R). Utilizando o formalismo da métrica, obtemos as equações de campo em termos de [Fórmula] e assumimos que F(R) seja uma fun c~ao de grau n da coordenada radial. Adotando uma aproximação, conseguimos obter soluções do tipo BN e analisamos suas quantidades termodinâmicas, como temperatura local, energia e capacidade térmica para qualquer n. Comparamos os resultados obtidos com o caso do BN de Scharzschild com um Monopo Global e também observamos se há influência do grau n nos efeitos termodinâmicos. / In this work we study the problem of a Black Hole (BH) in a region containing a Global Monopole in a f(R) gravity. We use the metric formalism to obtain the eld equations in terms of [Formula] and assume that F(R) is a n-degree function of the radial coordinate. Adopting an aproximation, we obtain BH solutions and analise the resulting thermodynamical quantities, such as local temperature, energy and heat capacity for all n's. We compare the results with the ones obtaines in the case of the Scharzschild BH with a Global Monopole and observe if there is an in uence of the degree n in the thermodynamical e ects.
394

Venom Peptides Cathelicidin and Lycotoxin Cause Strong Inhibition of Escherichia coli ATP Synthase

Azim, Sofiya, McDowell, Derek, Cartagena, Alec, Rodriguez, Ricky, Laughlin, Thomas F., Ahmad, Zulfiqar 01 June 2016 (has links)
Venom peptides are known to have strong antimicrobial activity and anticancer properties. King cobra cathelicidin or OH-CATH (KF-34), banded krait cathelicidin (BF-30), wolf spider lycotoxin I (IL-25), and wolf spider lycotoxin II (KE-27) venom peptides were found to strongly inhibit Escherichia coli membrane bound F1Fo ATP synthase. The potent inhibition of wild-type E. coli in comparison to the partial inhibition of null E. coli by KF-34, BF-30, Il-25, or KE-27 clearly links the bactericidal properties of these venom peptides to the binding and inhibition of ATP synthase along with the possibility of other inhibitory targets. The four venom peptides KF-34, BF-30, IL-25, and KE-27, caused ≥85% inhibition of wild-type membrane bound E.coli ATP synthase. Venom peptide induced inhibition of ATP synthase and the strong abrogation of wild-type E. coli cell growth in the presence of venom peptides demonstrates that ATP synthase is a potent membrane bound molecular target for venom peptides. Furthermore, the process of inhibition was found to be fully reversible.
395

Inhibition of ATPase Activity of Escherichia Coli ATP Synthase by Polyphenols

Dadi, Prasanna K., Ahmad, Mubeen, Ahmad, Zulfiqar 01 July 2009 (has links)
We have studied the inhibitory effect of five polyphenols namely, resveratrol, piceatannol, quercetin, quercetrin, and quercetin-3-β-d glucoside on Escherichia coli ATP synthase. Recently published X-ray crystal structures of bovine mitochondrial ATP synthase inhibited by resveratrol, piceatannol, and quercetin, suggest that these compounds bind in a hydrophobic pocket between the γ-subunit C-terminal tip and the hydrophobic inside of the surrounding annulus in a region critical for rotation of the γ-subunit. Herein, we show that resveratrol, piceatannol, quercetin, quercetrin, or quercetin-3-β-d glucoside all inhibit E. coli ATP synthase but to different degrees. Whereas piceatannol inhibited ATPase essentially completely (∼0 residual activity), inhibition by other compounds was partial with ∼20% residual activity by quercetin, ∼50% residual activity by quercetin-3-β-d glucoside, and ∼60% residual activity by quercetrin or resveratrol. Piceatannol was the most potent inhibitor (IC50 ∼14 μM) followed by quercetin (IC50 ∼33 μM), quercetin-3-β-d glucoside (IC50 ∼71 μM), resveratrol (IC50 ∼94 μM), quercitrin (IC50 ∼120 μM). Inhibition was identical in both F1Fo membrane preparations as well as in isolated purified F1. In all cases inhibition was reversible. Interestingly, resveratrol and piceatannol inhibited both ATPase and ATP synthesis whereas quercetin, quercetrin or quercetin-3-β-d glucoside inhibited only ATPase activity and not ATP synthesis.
396

Role of αPhe-291 Residue in the Phosphate-Binding Subdomain of Catalytic Sites of Escherichia Coli ATP Synthase

Brudecki, Laura, Grindstaff, Johnny J., Ahmad, Zulfiqar 15 March 2008 (has links)
The role of αPhe-291 residue in phosphate binding by Escherichia coli F1F0-ATP synthase was examined. X-ray structures of bovine mitochondrial enzyme suggest that this residue resides in close proximity to the conserved βR246 residue. Herein, we show that mutations αF291D and αF291E in E. coli reduce the ATPase activity of F1F0 membranes by 350-fold. Yet, significant oxidative phosphorylation activity is retained. In contrast to wild-type, ATPase activities of mutants were not inhibited by MgADP-azide, MgADP-fluoroaluminate, or MgADP-fluoroscandium. Whereas, 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) inhibited wild-type ATPase essentially completely, ATPase in mutants was inhibited maximally by ∼75%, although reaction still occurred at residue βTyr-297, proximal to αPhe-291 in the phosphate-binding pocket. Inhibition characteristics supported the conclusion that NBD-Cl reacts in βE (empty) catalytic sites, as shown previously by X-ray structure analysis. Phosphate protected against NBD-Cl inhibition in wild-type but not in mutants. In addition, our data suggest that the interaction of αPhe-291 with phosphate during ATP hydrolysis or synthesis may be distinct.
397

Applying Goodness-Of-Fit Techniques In Testing Time Series Gaussianity And Linearity

Jahan, Nusrat 05 August 2006 (has links)
In this study, we present two new frequency domain tests for testing the Gaussianity and linearity of a sixth-order stationary univariate time series. Both are two-stage tests. The first stage is a test for the Gaussianity of the series. Under Gaussianity, the estimated normalized bispectrum has an asymptotic chi-square distribution with two degrees of freedom. If Gaussianity is rejected, the test proceeds to the second stage, which tests for linearity. Under linearity, with non-Gaussian errors, the estimated normalized bispectrum has an asymptotic non-central chi-square distribution with two degrees of freedom and constant noncentrality parameter. If the process is nonlinear, the noncentrality parameter is nonconstant. At each stage, empirical distribution function (EDF) goodness-ofit (GOF) techniques are applied to the estimated normalized bispectrum by comparing the empirical CDF with the appropriate null asymptotic distribution. The two specific methods investigated are the Anderson-Darling and Cramer-von Mises tests. Under Gaussianity, the distribution is completely specified, and application is straight forward. However, if Gaussianity is rejected, the proposed application of the EDF tests involves a transformation to normality. The performance of the tests and a comparison of the EDF tests to existing time and frequency domain tests are investigated under a variety of circumstances through simulation. For illustration, the tests are applied to a number of data sets popular in the time series literature.
398

Millimeter-Wave Harmonically-Tuned Silicon Power Amplifiers for High Efficiency

Mortazavi, Seyed Yahya 09 September 2016 (has links)
This works demonstrates the feasibility of the inverse-Class-F harmonic tuning approach for mm-wave silicon PAs. This research addresses the challenges and limitations of the high efficiency inverse-Class-F PAs for mm-wave silicon technology. This work proposes different load networks to mitigate the challenges which are verified with implementations at different mm-wave frequencies with the highest power efficiency performances reported so far: PAE= 50% @ 24 GHz, PAE = 43% @ 41 GHz, and PAE = 23% @ 94 GHz. The design methodology and detailed analysis of the proposed load networks presented and verified with implementation and measured results. / Ph. D.
399

A HORSE POWER MEASUREMENT SYSTEM FOR NEXT GENERATION AIRCRAFT

Mangino, Fred 10 1900 (has links)
International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / Understanding the horsepower demands that electrical and hydraulic systems place on an aircraft engine is critical since this directly effects engine performance. The current methods of measuring horsepower have been mainly limited to lower rpm engines and are not suitable for higher rpm jet engines. L-3 Telemetry East has developed instrumentation for the F-22 instrumentation group that is capable of measuring horsepower loads on engine shafts that are rotating at up to 18000RPM. This paper describes the operation of this system.
400

Improved description of Earth's external magnetic fields and their source regions using satellite data

Shore, Robert Michael January 2013 (has links)
In near-Earth space, highly spatio-temporally variant magnetic fields result from solar-terrestrial magnetic interaction. These near-Earth external fields currently represent the largest source of error in efforts to model the magnetic field produced in the Earth’s interior. Starting in 1999, the Decade of Geopotential Field Research (Friis-Christensen et al., 2009) has greatly increased the amount of available low-Earth orbit (LEO) satellite magnetic data. These data have driven many advances in field modelling, yet have highlighted that LEO measurements are particularly susceptible to contamination from external fields. This thesis presents a series of studies attempting to describe the external fields in more detail, in order that they can be more effectively separated from the internal fields in magnetic modelling efforts. A range of analysis methods, different for each study, are applied to satellite and ground-based observatory data. Mandea and Olsen’s (2006) method of estimating the secular variation (SV) of the internal field from satellite data via ‘Virtual Observatories’ (VOs) is applied to synthetic data from the upcoming Swarm constellation satellite mission of the European Space Agency. Beggan (2009) found VOs constructed from CHAMP satellite data to be contaminated with external field signals which appeared to have a significant local time (LT) dependence. I find that utilising the increased coverage of LT sectors offered by the Swarm constellation geometry does not significantly decrease the contamination. Following this surprising result I tested a wide range of methods aimed at reducing the VO contamination from each parameterised external field source region. In anticipation of future studies using real data, I used the results of the tests to provide a more complete description of the external field variations affecting analyses of geographically-fixed magnetic phenomena when using satellite data and spherical harmonic analysis (SHA). Ionospheric electric currents flowing at LEO altitudes are known to violate the assumption of measurements taken in a source-free space, required in SHA-based models of the magnetic field. In order to better describe the electromagnetic environment at LEO altitudes, I use data from the Ørsted and CHAMP satellites to calculate the current density from Amp`ere’s integral. Vector magnetic data from discrete overflights of the two satellites (at different altitudes) are rotated into the along-track frame to define the integral loop and its ‘surface area’, permitting estimation of the predominantly zonal current density flowing in the region between the two orbital paths. I designed selection criteria to extract geometrically-stable overflights spanning the range of LTs twice in the 6 years of mutually available satellite vector data. From these overflights I resolve current densities in the range 0:1 μA=m2, with the distribution of current largely matching the LT progression of the Appleton anomaly. I applied detailed tests to check for biases intrinsic to the method, and present results free of systematic errors. The results are compared with the predictions of the CTIP (Coupled Thermosphere-Ionosphere-Plasmasphere) model of ionospheric composition and temperature, showing a typically good spatiotemporal agreement. I find persistent current intensifications between geomagnetic latitudes of 30 and 50 in the post-midnight, pre-dawn sector, a region which has been previously considered to be relatively free of currents. External fields induce currents in the Earth’s conducting mantle, the magnetic fields of which add to the field measured at and above the Earth’s surface. The morphology of the long-period inducing field is poorly resolved on timescales of months to years, reducing the accuracy of mantle induction studies (a key part of the Swarm mission). I improve the description of its morphology via the method of Empirical Orthogonal Functions (EOFs), which I apply to over a decade of ground-based observatory data. EOFs provide a decomposition of the spatiotemporal structures contained in the magnetic field data, with partitions arising from the data themselves, overcoming the relatively simplistic assumptions made about the inducing field morphology in LT. The results of vector data EOF analyses are presented, but I rely primarily on scalar analyses which are more fitting for this study. I overcome the limitations of the irregular observatory distribution with a novel spatial weighting matrix, combining the output from multiple EOF analyses to greatly improve the data coverage in LT. I find that the seasonal variation of the inducing field is more important than the variation of the symmetric ring current on annual periods, and that dawn-dusk asymmetry should be accounted for to increase the accuracy of mantle conductivity estimates based on data covering the decadal timescales of the solar cycle.

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