• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 24
  • 24
  • 5
  • 3
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 72
  • 22
  • 18
  • 16
  • 14
  • 11
  • 10
  • 10
  • 9
  • 8
  • 8
  • 7
  • 7
  • 7
  • 6
  • 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.
31

Influência das técnicas de seleção Swim-up e gradiente de densidade (Percoll ® e CapriPure ® ) na viabilidade espermática de amostras criopreservadas de sêmen caprino

BATISTA, André Mariano 12 February 2009 (has links)
Submitted by (edna.saturno@ufrpe.br) on 2016-08-01T15:31:24Z No. of bitstreams: 1 Andre Mariano Batista.pdf: 715032 bytes, checksum: 92e93d004a4a86c672f3ad4c9e8e4af1 (MD5) / Made available in DSpace on 2016-08-01T15:31:24Z (GMT). No. of bitstreams: 1 Andre Mariano Batista.pdf: 715032 bytes, checksum: 92e93d004a4a86c672f3ad4c9e8e4af1 (MD5) Previous issue date: 2009-02-12 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Sperm processing methods are routinely applied on the in vitro fertilization (IVF) systems for various species with the objective to remove seminal plasma/crioprotectant and to increase sperm quality. Aiming at study the sperm viability after use of the Swim-up or density gradient methods (Percoll® and CapriPure®) in frozen-thawed goat semen samples for use in assisted reproduction, six Boer goat semen samples were collected. Following, the samples were evaluated for concentration, progressive motility and morphology, diluted, packaged in straws (0.25 mL), frozen using machine and stored in liquid nitrogen. After thawing (37 oC for 30 s), sperm of all six goat were mixed-up making a pool and then were evaluated for progressive motility, membrane integrity (PI/DCF), acrossomal integrity (FITC/PNA) and mitochondrial membrane potential (JC-1). After that, the pool was split into two aliquots for the accomplishment of the sperm selection using the methods Swim-up and Percoll® (Experiment 1) and centrifugation in Percoll® and CapriPure® density gradient (Experiment 2). After use of each method of selection, the analyses was proceeded it from progressive motility, membrane integrity, acrossomal integrity and of mitochondrial integrity. Exp. 1 evidenced lower percentage of progressive motility spermatozoa (P<0.05) with intact plasma membrane (P<0.01) after use of Swim-up method, when compared with samples submitted to sperm preparation with Percoll®. In the Exp. 2, Percoll® gradient determined reduction (P<0.05) in percentage of acrosome intact spermatozoa when compared with percentage of the sample immediately after thawing, not having significant difference (P>0.05) if comparing submitted samples with the CapriPure® gradient. There were significant differences in the percentage of spermatozoa with high mitochondrial membrane potential inthe samples of semen submitted the selection using Percoll® (P<0.05) and CapriPure® (P<0.01), density gradients, when compared with the values of samples evaluated immediately after thawing. However, there were no significant difference (P<0.05) in the high mitochondrial membrane potential values between Percoll® and CapriPure® density gradients. On the basis the results of mobile spermatozoa and with the intact plasma membrane, are possible to conclude that to select viable sperm of frozen goat semen samples should use density gradient methods and CapriPure® is a good alternative to Percoll®. / Métodos de processamento espermático são rotineiramente utilizados nos sistemas de fertilização in vitro (FIV) de várias espécies, com o objetivo de remover o plasma seminal/crioprotetores e aumentar a qualidade espermática. Visando estudar a viabilidade espermática após utilização dos métodos Swim-up ou gradiente de densidade (Percoll® e CapriPure®) em amostras criopreservadas de sêmen caprino para uso em reprodução assistida, foram colhidas amostras de sêmen de seis reprodutores Boer. A seguir, as amostras foram avaliadas (motilidade progressiva, concentração, e morfologia), submetidas a duas lavagens em solução Tris, diluídas, envasadas em palhetas (0,25 mL), criopreservadas em máquina e armazenadas em botijão criobiológico (-196 oC). Após descongelação (37 oC; 30 segundos),procedeu-se à formação do pool das amostras dos reprodutores de cada dia de congelação e, a seguir, a avaliação de integridade de membrana (IP/DCF), integridade acrossomal (FITC/PNA) e potencial de membrana mitocondrial (JC-1). Em seguida, o pool foi dividido em duas alíquotas para a realização da seleção espermática utilizando os métodos Swim-up e Percoll® (Experimento 1) e centrifugação em gradiente de densidade Percoll® e CapriPure® (Experimento 2). Após utilização de cada método de seleção, procederam-se às análises de motilidade progressiva, concentração, integridade de membrana, integridade acrossomal e potencial de membrana mitocondrial. No Exp. 1 foram constatados menores porcentuais de espermatozóides portadores de motilidade progressiva (P<0,05) e de espermatozóides com membranas intactas (P<0,01) após utilização do método Swim-up, quando comparado as amostras submetidas à preparação espermática com Percoll®. No Exp. 2, o gradiente de Percoll® determinou redução (P<0,05) no porcentual de espermatozóides portadores de acrossoma intacto quando comparado ao porcentual da amostra imediatamente após a descongelação, não havendo diferença significativa (P>0,05) ao se comparar às amostras submetidas ao gradiente CapriPure®. Houve diferença significativa nos porcentuais de espermatozóides com alto potencial de membrana mitocondrial nas amostras de sêmen submetidas à seleção utilizando os gradientes de densidade Percoll® (P<0,05) e CapriPure® (P<0,01), quando comparado aos valores das amostras avaliadas imediatamente após a descongelação. No entanto, nenhuma diferença (P>0,05) foi observada entre os porcentuais de espermatozóides com alto potencial de membrana mitocondrial das amostras submetidas à seleção utilizando os gradientes de densidade Percoll® e CapriPure®. Com base nos resultados de espermatozóides móveis e com membranas intactas, é possível concluir que, para selecionar espermatozóides viáveis de amostras congeladas de sêmen caprino, deve-se usar a centrifugação em gradiente de densidade, e que o CapriPure® é uma boa alternativa ao uso doPercoll®.
32

Núcleo mediano da rafe e estresse de nado forçado: papel dos receptores de glutamato de tipo NMDA / Median Raphe Nucleus and Forced Swim stress: role of glutamate NMDA receptors

Diego Henrique dos Santos Pereira 26 May 2010 (has links)
Exposição a estressores incontroláveis leva a mudanças comportamentais e neuroquímicas, que têm sido associadas ao mau funcionamento da via Núcleo Mediano da Rafe (NMnR) Hipocampo Dorsal (HD). Estas mudanças comportamentais podem ser atenuadas por injeções intra hipocampais de NMDA ou de agonistas 5-HT1a. Ativação de receptores NMDA (NMDAr) aumentam os níveis de serotonina tanto no NMnR quanto no HD. Neste trabalho, nosso obejtivo foi analisar, em animais expostos ao Teste do nado forçado, se a ativação ou bloqueio dos receptores NMDA antes da exposição ao agente estressor ou 24 horas após essa exposição podem prevenir ou atenuar os efeitos do estresse. Ratos Wistar machos receberam duas injeções intra-NMnR de Salina (Sal), NMDA (1nmoles/0,2µL; agonista NMDAr) e/ou AP-7 (3nmoles/0,2µL; antagonista NMDAr) compondo os grupos experimentais: Sal+Sal, Sal+NMDA, AP-7+Sal, AP-7+NMDA. As drogas foram administradas em dois grupos experimentais, antes da pré-exposição ao nado forçado ou 24 horas após a pré-exposição e antes do teste. Foram analisados o tempo de latência para o primeiro episódio de imobilidade e o tempo total de imobilidade. A análise dos resultados mostrou que a administração de AP-7 antes da pré-exposição ou antes do teste e a administração de NMDA antes do teste, atenuaram os efeitos comportamentais causados pelo estresse, mostrando o envolvimento desses receptores nos mecanismos de adaptação a eventos aversivo e também que o momento no qual ocorre a intervenção farmacológica influencia essa adaptação. / Exposure to uncontrollable stressors leads to behavioral and neurochemical changes, which has been associated to mal functioning of the Median Raphe Nucleus (MnRN)-Dorsal Hippocampus (DH) serotoninergic pathway. These deficits can be attenuated by intra-hippocampal injections of NMDA antagonists or 5-HT1a agonists. Activation of MnRN glutamatergic NMDA receptors (NMDAr) increases serotonin release in both MnRN and DH. We previously showed that MnRN injections of NMDA (NMDAr agonist) and/or AP7 (NMDAr antagonist) after pre-test attenuated total time spent immobile in the forced swim test (FST). In this study we used the forced swim test to investigated whether activation and/or blockade of MnRN NMDAr before exposure to swim stress or 24 hours after the exposure, could prevent the effects of this stressor. Rats with cannulas aimed to the MnRN received two intracerebral injections (0.2µl each) of Saline (Sal), AP7 (3nmols) and/or NMDA (1nmol)(5 min interval), administered as follows: Sal+Sal, Sal+NMDA, AP7+Sal and AP7+NMDA. The animals were forced to swim for 15 min and 24 hrs later rats were re-exposed to FST One group received the treatment before exposure to stress and another group received it 24 hrs later, right before the test. Latency to display immobility and total time spent immobile were registered. After test, all animals were sacrificed under deep anesthesia, perfused and had their brains removed for histological analysis to confirm site of injection. Only animals who had their sites of injection confirmed were used in the analysis (ONEWAY ANOVA/Tukey test). Our data suggest that blockade of glutamatergic neurotransmission in the MnRN before exposure and 24 hrs later, and activation of this transmission 24 hrs later to stress prevents the behavioral consequences of forced swim stress.
33

Consistência e variabilidade do nado crawl em indivíduos habilidosos / Consistency and variability in the crawl swim of skillful individuals

Caio Graco Simoni da Silva 20 March 2008 (has links)
Ao observar os movimentos de indivíduos habilidosos praticando esporte, supõe-se que estes sejam a repetição de uma série de movimentos idênticos. Mas, o que no comportamento motor habilidoso parece idêntico a partir de uma observação geral, macroscópica, quando observado em detalhes, apresenta variabilidade. O comportamento motor habilidoso apresenta aspectos invariantes que resultam em um padrão característico da habilidade praticada (consistência) e também aspectos variantes, quando fatores microscópicos são focalizados. Assim qualquer tentativa de compreender o comportamento motor habilidoso deve considerar consistência e variabilidade como características complementares. No entanto, os poucos estudos de natação que consideraram estas características tiveram crianças como participantes. O objetivo do presente estudo foi investigar a consistência e a variabilidade da braçada do nado crawl em indivíduos habilidosos. Participaram 16 nadadores, todos voluntários, do sexo masculino, com média de idade de 20 anos. Destes, 8 com índice para disputar campeonatos nacionais e 8 com índice para participarem de campeonatos estaduais. Todos nadaram 2 x 50 metros em cada uma das três condições, ou seja, a 80%, 90% e 100% da velocidade máxima individual. Para fins de análise foram utilizadas medidas antropométricas, de desempenho global e de organização temporal, estas últimas correspondentes a macro e a microestrutura da braçada. Não foram detectadas diferenças entre os nadadores dos grupos Nacional e Estadual nas medidas antropométricas, mas os do grupo Nacional foram mais velozes nas condições 100% e 90%. O grupo Nacional, ao contrário do Estadual, manteve a macroestrutura da braçada nas três condições, e na condição de 80%, apresentou maior variabilidade nas medidas correspondentes a microestrutura que o grupo Estadual. Em conjunto, os resultados permitem concluir que o grupo Nacional é mais habilidoso que o Estadual desempenho e que adaptou seu comportamento a partir da redundância do sistema, enquanto o Estadual o fez a partir da modificação da estrutura / When observing the movements of skillful individuals practicing sport, one might suppose that they are a repetition of a series of identical movements. However, what seems to be identical in a skillful motor behavior from a general macroscopic view, is, in fact, variable when observed in detail. Skillful motor behavior presents invariant aspects that result in a particular pattern of the skill (consistency), but shows variant aspects, when microscopic factors are focused. Thus, any attempt to understand skillful motor behavior should consider consistency and variability as complementary features. However, the few studies of swimming that considered those features had children as participants. The aim of this study was to investigate consistency and variability in the crawl stroke of skillful individuals. Participants were 16 male volunteer swimmers with a mean age of 20 years. Eight with ranking to participate in national championships and eigth with ranking to participate in state championships. All swam 2 x 50 meters in each of three conditions, 80%, 90% and 100% of the individual maximum speed. For analisys purpose, antropometric, performance and temporal organization measures were employed, the last ones in correspondence to strokes macro and microstructures. On the antropometric measures no difference were detected between National and State groups but the National group was faster at 100% and 90% conditions. The National group, contrarily to State group, maintained stroke macrostructure within the three conditions and at the 80% condition, showed more variability on the the microstructure measures than the State group. Summing up, results lead to the conclusion that the National group is more skilled than the State group performance and that adapted his behavior do system redundancy while the State group did it through structure modification
34

Erhöhung der Antriebsleistungen beim Startsprung im Sportschwimmen

Graumnitz, Jens 07 July 2011 (has links)
Die vorliegende Arbeit soll den Nachweis erbringen, dass mit einem spezifi-schen Trainingsprogramm, welches aus einer Kombination von Techniktrai-ningsformen besteht, Teilkörperbewegungen beim Absprung vom Block so op-timiert werden, dass quantifizierbare Verbesserungen im Startabschnitt erzielt werden können. Ausgangspunkt ist die auf Wettkampfanalysen und Leistungsdiagnosemaßnahmen basierende Annahme, dass bei der Mehrheit der deutschen Nationalmannschaftsschwimmer erhebliche Reserven in der Ausführung der Absprungbewegung vom Block bestehen. Die Folge sind Nachteile der deutschen Sportler im Startabschnitt gegenüber der internationalen Konkurrenz. Ein spezielles Techniktrainingsprogramm wird als Trainingsintervention in einer Nachwuchstrainingsgruppe erprobt. Die Intervention erstreckt sich über zehn Wochen. Während der ersten sechs Wochen wird in wöchentlich vier Teiltrainingseinheiten ein Programm zur Sensibilisierung der Teilköperbewegungen absolviert. In weiteren vier Wochen erfolgt wöchentlich einmal ein Messplatztraining. Neun Wochen nach Abschluss des ersten Interventionszeitraumes wird die Intervention wiederholt. Im Vergleich mit einer Kontrollgruppe können über das gesamte Trainingsjahr 2007/2008 für die Interventionsgruppe größere Entwicklungsraten bei den Startleistungsmerkmalen nachgewiesen werden. Die gewonnenen Erkenntnisse unterstreichen die Notwendigkeit eines sorgfältig geplanten und kontinuierlich durchgeführten Techniktrainings zur Verbesserung der azyklischen Absprungbewegung vom Block ohne, dass die Entwicklung an-derer Leistungsvoraussetzungen beschränkt wird.
35

Environmental enrichment and serotonergic alterations on depressive-like states in rats

Arndt, David L. January 1900 (has links)
Master of Science / Department of Psychological Sciences / Mary Cain / Individuals suffering from depression primarily rely on pharmacological interventions to alleviate the incapacitating symptoms of the disorder. In addition to genetic differences underlying the etiology of depression, environmental factors play a key role as well. For example, environmental enrichment results in various neurotransmitter alterations, significantly affecting serotonin. To test the efficacy of novel antidepressant drugs in the preclinical laboratory setting, researchers commonly implement the forced swim test (FST) for rats or mice. However, the effect of environmental enrichment on the expression of depressive-like states in the FST is unclear, and it is unknown whether environmental enrichment or social isolation can alter the efficacy of the commonly prescribed antidepressant drug, fluoxetine. In the present study, locomotor activity and FST performance were measured after 30 days of rearing in enriched (EC), standard (SC), and isolated (IC) conditions. Results showed that regardless of the significant effect of fluoxetine on locomotor activity in EC, SC, and IC rats, fluoxetine failed to increase swimming and decrease immobility in all three environmental conditions, with enriched-fluoxetine rats displaying significantly less swimming behavior in the FST than enriched rats receiving vehicle control injections. These results suggest that differential rearing, specifically environmental enrichment, can alter the efficacy of antidepressants and may suggest that enrichment reverses the effects of fluoxetine.
36

DEPTH AND DEVELOPMENT OF THE SONIC SYSTEM IN DEEP-SEA MACROURID FISHES ON THE CONTINENTAL SLOPE

Wrenn, Jonothan 01 January 2016 (has links)
Work on sound production of deep-sea fishes has been limited to anatomy, and no sounds from identified species have been recorded on the continental slope. Here I examined the sonic muscles of six species in the family Macrouridae by depth (Coelorhincus carminatus, Nezumia bairdii, Coryphaenoides rupestris, Nezumia equalis, Coryphaenoides armatus, Coryphaenoides carapinus,). Due to increasingly limited food with depth, I hypothesized that sonic muscle development would decrease with depth. Sonic muscles were intrinsic and occurred in males and females. Swimbladder and sonic muscle dimensions increased linearly with fish size, but there were no clear differences with depth suggesting sound production remains important in deeper species.
37

Participação do sistema glutamatérgico do córtex pré-frontal medial ventral na modulação das consequências comportamentais do estresse de nado forçado / Participation of the glutamatergic system of the ventral medial prefrontal cortex in the modulation of behavioral consequences of forced swimming stress.

Pereira, Vitor Silva 20 July 2011 (has links)
Acredita-se que quantidades elevadas de glutamato estejam relacionadas à neurobiologia da depressão e trabalhos recentes indicam que a quantidade de glutamato cortical está aumentada em pacientes depressivos quando comparada a indivíduos sadios. Dentre as estruturas corticais, o córtex pré-frontal medial ventral (CPFMv), dividido em infralímbico (IL) e pré-límbico (PL), tem sido mais frequentemente implicado no desenvolvimento de transtornos mentais, como a depressão. Considerando evidências de que o IL e o PL podem agir de forma diferente quanto ao controle emocional em resposta ao estresse, o presente trabalho visou avaliar a hipótese de participação da neurotransmissão glutamatérgica do CPFMv, IL e PL, no desenvolvimento das respostas comportamentais ao estresse de nado forçado, um modelo preditivo de efeitos antidepressivos. Para tal, investigamos os efeitos induzidos pela administração no IL ou no PL, de LY 235959, um antagonista dos receptores glutamatérgicos do tipo NMDA, em três momentos diferentes, em animais submetidos ao teste do nado forçado. A administração de LY 235959, no IL ou PL, produziu efeitos do tipo antidepressivo, sendo esse efeito sensível ao tempo de administração da droga em relação à exposição ao nado forçado. Sendo assim, foi observado efeito antidepressivo quando o bloqueio glutamatérgico no PL ocorreu imediatamente após o nado ou antes da re-exposição ao estresse; enquanto no IL, o tratamento promoveu efeito antidepressivo apenas quando administrado antes da re-exposição ao nado. Portanto, os resultados sugerem que a neurotransmissão glutamatérgica mediada por receptores NMDA no CPFMv contribui para o desenvolvimento de consequências comportamentais do estresse, de modo que o bloqueio desses receptores facilitaria a adaptação ao estresse e induziria efeitos do tipo-antidepressivo. Os resultados sugerem, ainda, que o PL e o IL participam de maneira semelhante na modulação desses processos. / It is believed that high amounts of glutamate are related to the neurobiology of depression. Recent studies indicate that the amount of cortical glutamate is increased in depressed patients compared to healthy subjects. Among the cortical structures, the ventral medial prefrontal cortex (CPFMv), divided into infralimbic (IL) and prelimbic (PL) has been most often implicated in the development of mental disorders, such as depression. Considering that IL and PL play different roles on the emotional control in response to stress, this study was aimed to evaluate the hypothesis that the activation of glutamate NMDA receptors within the CPFMv, IL and PL, would facilitate the development of forced swimming-induced behavioral responses, an animal model predictive of antidepressants effects. To this end, we investigated the effects induced by the administration in the PL or the IL of LY 235959, an antagonist of NMDA receptors, at three different times, in animals submitted to the forced swimming test. The administration of LY 235959, in the IL or PL, produced antidepressant-like effects, and this effect is sensitive to moment of drug administration in relation to exposure to forced swimming. Thus, the antidepressant-like effect was observed when blocking the NMDA blockade into the PL occurred immediately after swimming or before re-exposure to stress, whereas in the IL, such treatment promoted antidepressant-like effect only when administered before re-exposure to swimming. Therefore, the results suggest that the glutamatergic neurotransmission mediated by NMDA receptors in the CPFMv contributes to the development of behavioral consequences of stress, so that blocking these receptors would facilitate the adaptation to stress and induce antidepressant-like effects. The results also suggest that PL and IL may be similarly involved in modulating these processes.
38

Análise da força de mordida, atividade eletromiográfica e espessura dos músculos masseter e temporal em nadadores de elite - modalidade Crawl / Analysis of bite force, electromiographic activity and thickness of masseter and temporal muscles in elite swimmers - crawl modality

Fioco, Evandro Marianetti 12 December 2017 (has links)
O esporte aquático em todas as modalidades requer combinação de força e eficiência, pois a água tem densidade maior que o ar, e o nadador de elite que tem jornada aquática intensa com movimentos repetitivos na locomoção e respiração pode apresentar modificação de função e forma das estruturas que compõem o organismo humano. Esta pesquisa avaliou a força de mordida molar máxima, atividade eletromiográfica, eficiência mastigatória e espessura dos músculos masseter e temporal de nadadores de elite que utilizaram variações de métodos respiratórios do nado crawl para o lado direito e esquerdo, e comparou os resultados com indivíduos sedentários. Participaram 18 indivíduos na faixa etária entre 15 e 25 anos que foram distribuídos em três grupos: sedentários/controles (GC; idade média: 15,00 ± 0,98 anos; n=6); atletas que realizaram respiração para o lado esquerdo no nado crawl (GE; idade média 17,00 ± 2,44 anos; n=6) e atletas que realizaram respiração para o lado direito no nado crawl (GD; idade média 21,00 ± 2,44 anos; n=6). O dinamômetro digital Kratos foi utilizado para determinar a força de mordida molar máxima. O eletromiógrafo MyoSystem BR1 foi utilizado para avaliar a atividade eletromiográfica em repouso mandibular, lateralidade direita, lateralidade esquerda, protrusão, apertamento dental em contração voluntária máxima, mastigação habitual e não habitual (eficiência mastigatória). Foi utilizado o ultrassom Sono Site Titan para mensurar a espessura muscular em repouso e apertamento dental em contração voluntária máxima. Os dados obtidos foram tabulados e submetidos à análise estatística (SPSS 21.0, ANOVA; p &le; 0,05). GE e GD demonstraram menor atividade eletromiográfica nas condições posturais da mandíbula quando comparados a GC. Foi observado correto padrão funcional nos movimentos mandibulares nas diferentes avaliações clínicas, com diferença significante na lateralidade direita para o músculo temporal esquerdo (p=0,04). GD e GE apresentaram maior eficiência mastigatória em relação ao GC, com diferença significante para o músculo temporal esquerdo na mastigação com uva passa (p=0,004). Não ocorreram diferenças significantes nas médias da espessura muscular e força de mordida molar entre os nadadores de elite e indivíduos sedentários. Estes resultados sugerem que nadadores de elite que utilizaram o nado crawl com métodos respiratórios variados apresentaram alterações funcionais nos músculos masseter e temporal. / All modalities of water sports require a combination of strength and efficiency, as the water has a higher density than air, and the elites swimmer has an intense aquatic journey with repetitive movements in the locomotion and breathing may present a modification of the function and shape of the body structures. This study evaluated the molar bite force, electromyographic activity, masticatory efficiency and thickness of the masseter and temporal muscle of elites swimmers used changes in respiratory methods both in right and left for crawl modality and compared the results with sedentary individuals. 18 individuals, aged between 15 and 25 years, were divided into three groups: sedentary/control (average ± SD 15.00 ± 0.98 years, n = 6; CG), athletes underwent respiration to the left side in the crawl swim (average ± SD 17.00 ± 2.44 years, n = 6; LG) and athletes who underwent respiration to the right side in the crawl swim (average ± SD 21.00 ± 2.44 years, n = 6, RG). The Kratos digital dynamometer was used to determine the molar bite force. The MyoSystem BR1 electromyograph was used to evaluate the electromyographic activity at mandibular rest, right laterality, left laterality, protrusion, maximum voluntary contraction, habitual and non-habitual mastication (masticatory efficiency). Sono Site Titan ultrasound was used to measure muscle thickness at rest and dental tightening at maximum voluntary contraction. The data were tabulated and submitted to statistical analysis (SPSS 21.0, ANOVA; P &le; 0.05). LG and RG demonstrated lower electromyographic activity in postural conditions of the mandible when compared to CG. The correct mandibular neuroanatomic movement was observed in almost all muscles, with a significant difference in right laterality for the left temporal muscle (P=0.04). RG and LG presented greater masticatory efficiency in relation to the CG, with a significant difference for the left temporal muscle in chewing with raisins (P=0.004). There were no significant differences in the average muscle thickness and molar bite force between elite swimmers and sedentary individuals. These results suggest that elites swimmers perform crawl swimming with varied respiratory methods had functional alterations in the masseter and temporal muscles.
39

The modulatory effects of sildenafil and the cholinergic system on antidepressant action in a rat model of depression / J.D. Clapton

Clapton, Johannes Daniel January 2006 (has links)
Thesis (M.Sc. (Pharmacology))--North-West University, Potchefstroom Campus, 2007.
40

The hydrological effects of changes in forest area and species composition in the federal state of Brandenburg, Germany

Wattenbach, Martin January 2008 (has links)
This thesis aims to quantify the human impact on the natural resource water at the landscape scale. The drivers in the federal state of Brandenburg (Germany), the area under investigation, are land-use changes induced by policy decisions at European and federal state level. The water resources of the federal state are particularly sensitive to changes in land-use due to low precipitation rates in the summer combined with sandy soils and high evapotranspiration rates. Key elements in landscape hydrology are forests because of their unique capacity to transport water from the soil to the atmosphere. Given these circumstances, decisions made at any level of administration that may have effects on the forest sector in the state are critical in relation to the water cycle. It is therefore essential to evaluate any decision that may change forest area and structure in such a sensitive region. Thus, as a first step, it was necessary to develop and implement a model able to simulate possible interactions and feedbacks between forested surfaces and the hydrological cycle at the landscape scale. The result is a model for simulating the hydrological properties of forest stands based on a robust computation of the temporal and spatial LAI (leaf area index) dynamics. The approach allows the simulation of all relevant hydrological processes with a low parameter demand. It includes the interception of precipitation and transpiration of forest stands with and without groundwater in the rooting zone. The model also considers phenology, biomass allocation, as well as mortality and simple management practices. It has been implemented as a module in the eco-hydrological model SWIM (Soil and Water Integrated Model). This model has been tested in two pre-studies to verify the applicability of its hydrological process description for the hydrological conditions typical for the state. The newly implemented forest module has been tested for Scots Pine (Pinus sylvestris) and in parts for Common Oak (Quercus robur and Q. petraea) in Brandenburg. For Scots Pine the results demonstrate a good simulation of annual biomass increase and LAI in addition to the satisfactory simulation of litter production. A comparison of the simulated and measured data of the May sprout for Scots pine and leaf unfolding for Oak, as well as the evaluation against daily transpiration measurements for Scots Pine, does support the applicability of the approach. The interception of precipitation has also been simulated and compared with weekly observed data for a Scots Pine stand which displays satisfactory results in both the vegetation periods and annual sums. After the development and testing phase, the model is used to analyse the effects of two scenarios. The first scenario is an increase in forest area on abandoned agricultural land that is triggered by a decrease in European agricultural production support. The second one is a shift in species composition from predominant Scots Pine to Common Oak that is based on decisions of the regional forestry authority to support a more natural species composition. The scenario effects are modelled for the federal state of Brandenburg on a 50m grid utilising spatially explicit land-use patterns. The results, for the first scenario, suggest a negative impact of an increase in forest area (9.4% total state area) on the regional water balance, causing an increase in mean long-term annual evapotranspiration of 3.7% at 100% afforestation when compared to no afforestation. The relatively small annual change conceals a much more pronounced seasonal effect of a mean long-term evapotranspiration increase by 25.1% in the spring causing a pronounced reduction in groundwater recharge and runoff. The reduction causes a lag effect that aggravates the scarcity of water resources in the summer. In contrast, in the second scenario, a change in species composition in existing forests (29.2% total state area) from predominantly Scots Pine to Common Oak decreases the long-term annual mean evapotranspiration by 3.4%, accompanied by a much weaker, but apparent, seasonal pattern. Both scenarios exhibit a high spatial heterogeneity because of the distinct natural conditions in the different regions of the state. Areas with groundwater levels near the surface are particularly sensitive to changes in forest area and regions with relatively high proportion of forest respond strongly to the change in species composition. In both cases this regional response is masked by a smaller linear mean effect for the total state area. Two critical sources of uncertainty in the model results have been investigated. The first one originates from the model calibration parameters estimated in the pre-study for lowland regions, such as the federal state. The combined effect of the parameters, when changed within their physical meaningful limits, unveils an overestimation of the mean water balance by 1.6%. However, the distribution has a wide spread with 14.7% for the 90th percentile and -9.9% for the 10th percentile. The second source of uncertainty emerges from the parameterisation of the forest module. The analysis exhibits a standard deviation of 0.6 % over a ten year period in the mean of the simulated evapotranspiration as a result of variance in the key forest parameters. The analysis suggests that the combined uncertainty in the model results is dominated by the uncertainties of calibration parameters. Therefore, the effect of the first scenario might be underestimated because the calculated increase in evapotranspiration is too small. This may lead to an overestimation of the water balance towards runoff and groundwater recharge. The opposite can be assumed for the second scenario in which the decrease in evapotranspiration might be overestimated. / Das übergreifende Ziel der vorliegenden Arbeit ist es, die Interaktion zwischen Landnutzungsänderung und dem Landschaftswasserhaushalt zu quantifizieren. Das Untersuchungsgebiet für die Analyse ist das Land Brandenburg. Bedingt durch seine Kombination geringer Sommerniederschläge mit der Dominanz sandiger Böden und hoher Verdunstungsraten, insbesondere von den großflächigen Wäldern und Forsten, ist es besonders empfindlich gegenüber Landnutzungsänderung. Waldflächen sind Schlüsselelemente im Landschaftswasserhaushalt, da sie den Bodenwasserspeicher effizienter mit der Atmosphäre koppeln als die meisten anderen Vegetationsformen. Im ersten Teil der Arbeit war es daher notwendig, ein geeignetes Modellkonzept zu finden. Der Ansatz sollte in der Lage sein, die hydrologischen Effekte auf Landschaftsebene zu modellieren, ohne dabei die Datenverfügbarkeit in diesem Anwendungsbereich zu überschreiten. Das entwickelte Modellkonzept wurde in das ökohydrologische Einzugsgebietsmodell SWIM (Soil Water Integrated Model) integriert. Nach einer Test- und Entwicklungsphase konnte das Modell für die integrierte Analyse der Wirkung von zwei Szenarien auf den Landeswasserhaushalt verwendet werden. Das erste Szenario beschäftigt sich mit der möglichen Zunahme der Waldfläche als Folge der Neuausrichtung der Agrarsubventionspolitik der Europäischen Union. Die Waldflächenzunahme führt zu einer Steigerung der Evapotranspiration im langjährigen Mittel. Das zweite Szenario behandelt die Auswirkung des Brandenburger Waldumbauprogramms und hat eine vergleichsweise geringe Abnahme der langjährigen mittleren Verdunstung zur Folge. Der lineare mittlere Verlauf überdeckt ein ausgeprägtes räumliches und saisonales Muster der Veränderung. Die Zonen starker Effekte der beider Szenarien überlappen sich nur in einigen Fällen, so ist es möglich, dass die positiven Wirkungen des Waldumbauprogramms in einigen Regionen durch eine mögliche Ausweitung der Waldfläche aufgehoben werden. Die vorgestellten Ergebnisse zeigen deutlich, dass Landnutzungsänderungen, die durch politische oder administrative Entscheidungen ausgelöst werden, Auswirkungen auf elementare Landschaftsfunktionen wie den Wasserhaushalt haben. Es wird deutlich, dass ein integrativer Modellierungsansatz, der die wahrscheinlichen Wirkungen administrativer Entscheidungen in Betracht zieht, Grundlagen für eine nachhaltige Entwicklung liefern kann. Diese Ergebnisse werden umso relevanter, je stärker die betroffene Ressource bereits eingeschränkt ist. In Bezug auf die Wasserressourcen im Land Brandenburg ist das der Fall und aktuelle Studien zum Globalen Wandel in der Region prognostizieren eine Verschärfung dieser Situation.

Page generated in 0.0222 seconds