• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 97
  • 73
  • 53
  • 21
  • 18
  • 14
  • 6
  • 4
  • 1
  • 1
  • Tagged with
  • 325
  • 116
  • 115
  • 72
  • 71
  • 70
  • 70
  • 70
  • 70
  • 70
  • 59
  • 49
  • 45
  • 44
  • 44
  • 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.
11

Desnutrição pré-natal: repercussões sobre odesenvolvimento do sistema locomotor em ratos

Elisa Toscano Meneses da Silva, Ana 31 January 2008 (has links)
Made available in DSpace on 2014-06-12T23:02:06Z (GMT). No. of bitstreams: 2 arquivo4037_1.pdf: 2518804 bytes, checksum: 4866d252913edca4356764c7f981f985 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2008 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Nesta tese avaliamos as repercussões da desnutrição intra-uterina sobre o desenvolvimento do sistema locomotor em ratos. Foram utilizados ratos Wistar neonatos provenientes de mães que receberam dieta controle (Grupo Controle C, 17% de proteína) ou uma dieta hipoprotéica e isocalórica (Grupo Desnutrido D, 7,8% de proteína). Após o nascimento os animais receberam a dieta normoprotéica até as respectivas idades experimentais. Os componentes contráteis e elásticos em série e em paralelo foram estudados no soleus e extensor digitorum longus (EDL) aos 25 e 90 dias de vida. A analise histológica das fibras musculares foi também realizada. Do 1o ao 21o dia de vida, os animais foram avaliados quanto ao seu crescimento somático, maturação de características físicas e de reflexos. No 8o, 14o, 17o, 21o e 90o, a atividade locomotora e a trajetória desempenhada pelos animais foram analisadas. O Grupo D apresentou atrofia muscular e diminuição da força muscular no músculo aos 25 e 90 dias. Houve aumento na velocidade máxima de encurtamento no soleus e EDL aos 25 e 90 no grupo D. A rigidez do componente elástico em série nos desnutridos foi aumentada no soleus, enquanto que no EDL foi observada uma diminuição dessa rigidez aos 25 dias de vida. Houve aumento da rigidez dos elementos elásticos em paralelo em ambos nos músculos de desnutridos aos 25 dias. A análise das proporções dos tipos de fibras no grupo D aos 25 e 90 dias revela aumento nas fibras tipo IIa no soleus e aumento das fibras IIb e diminuição das fibras IIa no EDL. Houve redução do crescimento somático e retardo na maturação das características físicas e dos reflexos nos desnutridos. Na avaliação da atividade locomotora houve aumento da distância percorrida, da velocidade e da potência média no 14o e 17o dia de vida nos desnutridos. O tempo que o animal desnutrido permaneceu parado diminuiu do 14o ao 21o dia, aumentando o número de paradas e diminuindo a duração média em cada parada no 14o e 17o dia de vida. Na análise da trajetória desses animais observa-se que aos 14o e 17o dias os permanecem mais tempo nas áreas mais periféricas do campo e esse comportamento se inverte aos 90 dias de idade no grupo D. A persistência de certas alterações estruturais e funcionais revela que a adaptação intra-uterina do sistema músculo-esquelético, para enfrentar a desnutrição, tem conseqüências permanentes o que pode comprometer a locomoção do animal
12

A Comparison of Two Approaches to Presenting Two Series of Locomotor Skills to Children with Minimal Brain Dysfunction

Clark, Sharon E. 12 1900 (has links)
Because the child with minimal brain dysfunction has problems perceiving the world around him, and as a result, is hindered in the learning process; the purpose of this study was to determine the effect of two different methods of instruction in and practice of two series of similar locomotor skills upon the ability of children with minimal brain dysfunction to switch from one activity to another within each series.
13

Vastly Differing Circadian Rhythms of the Spiders Cyrtophora citricola and Allocyclosa bifurca Suggest Short Clocks Pair with Diurnal Crypsis

Upham, Jessica, Jones, Thomas, Moore, Darrell 25 April 2023 (has links)
Circadian rhythms are outputs of the internal clock that regulates the daily functions of almost all living organisms. Circadian rhythms are typically 24 hours because they are synchronized by external cues such as the natural light/dark cycles of the environment. When external cues are removed, the circadian rhythm “free-runs,” thus revealing the organism’s endogenous circadian period. Recent studies have found that the trashline orbweaving spiders Cyclosa turbinata and Allocyclosa bifurca have abnormally short circadian rhythms of approximately 19 and 18 hours, respectively. Trashline orbweavers construct a line of debris made of prey carcasses in the center of their web and then remain undetectable by being cryptic within their trashline. Despite similar circadian rhythms and web-building behaviors, recent genetic findings indicate that these species actually are not closely related. In fact, both genetic and morphological data now suggest A. bifurca is more closely related to Cyrtophora citricola, the Tropical Tent-web spider. This would suggest that trashline behavior and exceptionally short circadian clocks evolved independently in C. turbinataand A. bifurca. This study analyzed the circadian rhythm of C. citricola and compared it to the circadian rhythm of A. bifurca. If C. citricola has an abnormally short clock like A. bifurca, this would indicate that the evolution of the short clock preceded the divergence of these species’ lineages. However, if C. citricola has a more typical clock, this would suggest that the unusually short clock evolved in the A. bifurca lineage and may be more ecologically linked to the trashline behavior. Thirty-two female C. citricola were collected in Southern Florida and had their locomotor activity measured over four days of 12:12 light/dark cycles followed by complete darkness to determine their circadian free-running periods (FRP). Cyrtophora citricola was found to have a more typical FRP of 24.0 + 0.43 hours. Despite being closely related, C. citricola and A. bifurca differ significantly in their circadian rhythms, suggesting that short circadian rhythms may be ecologically linked with trashline behavior.
14

Locomotor Patterns of Teleost Fish under Constant Conditions of Light and Darkness

Kapoor, Narinder Nath 03 1900 (has links)
Remote photoelectric monitoring of the locomotion of four freshwater teleosts in an experimental tank established that all species described non-random locomotor patterns which were affected by light intensity. A partial analysis was made of some of the characteristics of these patterns with emphasis on the direction and degree of turning. / Thesis / Doctor of Philosophy (PhD)
15

The Response of the Red-Backed Salamander (<i>Plethodon Cinereus</i>) to Temperature and Chemical Cues From a Predator and a Competitor

Kirshberger, James Henry 01 August 2007 (has links)
No description available.
16

Sublethal effects of an acetylcholinesterase-inhibiting pesticide on fitness-related traits in the western fence lizard (Sceloporous occidentalis)

DuRant, Sarah E. 12 January 2007 (has links)
Pesticides are commonly used around the world for a multitude of different purposes and on diverse habitats, including agricultural fields, wetlands, and personal lawns and gardens. Currently, acetylcholinesterase (AChE)-inhibiting pesticides are among the most prevalently used chemical pesticides in the United States. A wealth of information exists on sub-cellular responses of organisms, primarily birds, mammals, and fish, exposed to these compounds. However, the effects of AChE-inhibiting pesticides at the whole-organism level, most importantly effects relevant to an individual's fitness, have received less attention. My Master's research focused on describing the effects of carbaryl, an AChE-inhibiting pesticide, on several fitness-related traits in the western fence lizard (Sceloporus occidentalis). Reptiles are the least studied vertebrate taxon in ecotoxicological studies even though contaminants are suspected in contributing to recent population declines. Using multiple dose concentrations within the range expected to occur in nature (based on EPA application rates and published pesticide residues on insects), I quantified the effects of carbaryl on sprint performance energy acquisition, and energy allocation, traits which could have important implications for the animal's ability to avoid predators, capture prey, and grow and reproduce. I found that at the highest dose concentration, lizards experienced a decrease in arboreal and terrestrial locomotor performance, a decrease in energy acquisition, and alterations in energy allocation. My findings suggest that acute exposure to high concentrations of carbaryl can have important sublethal consequences on fitness-related traits in S. occidentalis. Future studies should examine the consequences of multiple-pulse exposures to AChE-inhibiting pesticides on reptiles. / Master of Science
17

Estratégia de ensino anatômico a violonistas para prevenção de lesões do aparelho locomotor / Strategy of anatomical teaching to the violonistas for prevention of injuries of the locomotor appliance

Somera Junior, Renato 27 November 2012 (has links)
Made available in DSpace on 2016-01-26T12:51:44Z (GMT). No. of bitstreams: 1 renatosomerajunior_dissert.pdf: 2067969 bytes, checksum: d5bd1e5c55418b34fe82f25b37f99179 (MD5) Previous issue date: 2012-11-27 / Introduction: Acoustic Guitar players represent the most part of the instrumentalists and their activities involve repetitive efforts or static posture, which makes them likely candidates to develop labor disease, most times due to absolute lack of information. The objective of this study was to prepare an illustrative manual of the locomotor system, specifically directed to guitarists, for injury prevention. Method: 61 guitarists (students, professors, semi-professionals and professionals) in the city of São José do Rio Preto SP were taken into consideration, with the application of a questionnaire in order to estimate knowledge on bones, muscles and joints intrinsically associated with the praxis of guitar musical performances. As results, 83.5 % of the respondents had no specific anatomical knowledge, 62.3 % received no orientation on the best physical postures to perform the guitar; 63.93 % do not effect prior stretching for upper limbs or other body regions; 50.82 % do not practice muscle warming before the practice, and 52.46 % do not make pauses during the activity. Body areas that were constantly used during practice with the guitar encompassed right wrist (70.49%), left wrist (59.01%), right hand (63.93%) and left hand (50.81%). Spearman's correlation was used to estimate the relation between discomfort and hours of daily practice with guitar and it indicated positive correlation of low degree on right (r=0.3536) and left wrists (r=0.3226) and on the left hand (r=0.3431). Production of Illustrated Manual of Human Anatomy specific to the Locomotor System promotes teaching strategy to prevent injuries, traumas or musculoskeletal origin pathologies of guitarists, from complete beginners to instrumentalists. / Introdução: Violonistas representam a maioria dos instrumentistas e suas atividades envolvem esforços repetitivos ou postura estática, o que assim os torna prováveis candidatos a desenvolver doença laboral, a maioria das vezes por absoluta falta de informação. O objetivo do presente estudo foi elaborar manual ilustrativo do aparelho locomotor, especificamente direcionado a violonistas, para prevenção de lesões. Método: Foram considerados 61 violonistas (estudantes, docentes, semi-profissionais e profissionais) da cidade de São José do Rio Preto SP, com aplicação de questionário a fim de estimar conhecimento referente a ossos, músculos e articulações intrinsecamente associados à práxis de execuções musicais de violão. Como resultados, 83,5% dos respondentes não tinham conhecimento anatômico específico; 62,3% não receberam orientação sobre as melhores posturas físicas para executar o violão; 63,93% mencionam não efetuar alongamento prévio dos membros superiores ou de outras regiões corporais; 50,82% não praticam aquecimento muscular antes da prática, e 52,46% não efetuam pausas durante a atividade. Áreas corporais constantemente utilizadas durante a prática com o violão englobaram pulso direito (70,49%), pulso esquerdo (59,01%), mão direita (63,93%) e mão esquerda (50,81%). Correlação de Spearman foi usada para estimar relação entre desconforto e horas de prática diária com violão indicou correlação positiva de grau baixo nos pulsos direito (r=0,3536) e esquerdo (r=0,3226) e na mão esquerda (r=0,3431). Confecção de Manual Ilustrado de Anatomia Humana específica ao Aparelho Locomotor promove estratégia de ensino para prevenir lesões, traumas ou patologias de origem musculoesquelética a violonistas, desde iniciantes até instrumentistas.
18

Relações evolutivas entre ecologia e morfologia serpentiforme em espécies de lagartos microteiídeos (Sauria: Gymnophthalmidae) / Evolutionary relationship between ecology and snakelike morphology in species of microtelid lizards (Sauria: Gymnophthalmidae)

Mariana Bortoletto Grizante 18 December 2009 (has links)
A evolução da morfologia serpentiforme, caracterizada simultaneamente pelo alongamento do corpo e pela redução de membros locomotores, ocorreu repetidas vezes durante a história evolutiva de Squamata. Alterações em parâmetros morfológicos relacionados à locomoção de um organismo afetam diretamente seu desempenho em atividades essenciais à sobrevivência e à produção de descendentes e, portanto, espera-se que estejam relacionadas a adaptações a características do ambiente ocupado por ele. Estudos ecomorfológicos sugerem que o surgimento de morfologias serpentiformes em Squamata ocorreu frequentemente associado à ocupação de diferentes habitats, resultando em duas ecoformas distintas: espécies epígeas, que geralmente possuem tronco e cauda alongados, e espécies fossoriais, que geralmente possuem tronco alongado e cauda curta. O objetivo deste trabalho foi investigar a existência de relações evolutivas entre ecologia e aspectos morfológicos, como alongamento do corpo e redução dos membros, em espécies de lagartos neotropicais da família Gymnophthalmidae, avaliando como essas mudanças influenciam seu desempenho locomotor. / Evolution of snakelike morphology, characterized by both body elongationand and limb reduction, has ocurred several times during evolutionary history of Squamata. Changes in morphological parameters related to locomotion directly affect organismal performance in several activities that are crucial to survival and descendent produciton. Therefore, these morphological changes are expected to be adaptive to the environment where the organism occurs. Ecomorphological studies suggests that the evolution of snakelike morphologies in Squamata ocurred frequently associated to the ocupation of different habitats, giving rise to two distinct ecomorphs: grass-swimming species, which generally have elongation of trunk and tail, and fossorial species, which generally have elongation of trunk and short tail. The aim of the present study was to investigate the existence of evolutionary relationships between ecology and morphological aspects like body elongation and limb reduction in species of neo-tropical lizard family Gymnophthalmidae, evaluating how these evolutionary changes affect locomotor performance.
19

Relações evolutivas entre ecologia e morfologia serpentiforme em espécies de lagartos microteiídeos (Sauria: Gymnophthalmidae) / Evolutionary relationship between ecology and snakelike morphology in species of microtelid lizards (Sauria: Gymnophthalmidae)

Grizante, Mariana Bortoletto 18 December 2009 (has links)
A evolução da morfologia serpentiforme, caracterizada simultaneamente pelo alongamento do corpo e pela redução de membros locomotores, ocorreu repetidas vezes durante a história evolutiva de Squamata. Alterações em parâmetros morfológicos relacionados à locomoção de um organismo afetam diretamente seu desempenho em atividades essenciais à sobrevivência e à produção de descendentes e, portanto, espera-se que estejam relacionadas a adaptações a características do ambiente ocupado por ele. Estudos ecomorfológicos sugerem que o surgimento de morfologias serpentiformes em Squamata ocorreu frequentemente associado à ocupação de diferentes habitats, resultando em duas ecoformas distintas: espécies epígeas, que geralmente possuem tronco e cauda alongados, e espécies fossoriais, que geralmente possuem tronco alongado e cauda curta. O objetivo deste trabalho foi investigar a existência de relações evolutivas entre ecologia e aspectos morfológicos, como alongamento do corpo e redução dos membros, em espécies de lagartos neotropicais da família Gymnophthalmidae, avaliando como essas mudanças influenciam seu desempenho locomotor. / Evolution of snakelike morphology, characterized by both body elongationand and limb reduction, has ocurred several times during evolutionary history of Squamata. Changes in morphological parameters related to locomotion directly affect organismal performance in several activities that are crucial to survival and descendent produciton. Therefore, these morphological changes are expected to be adaptive to the environment where the organism occurs. Ecomorphological studies suggests that the evolution of snakelike morphologies in Squamata ocurred frequently associated to the ocupation of different habitats, giving rise to two distinct ecomorphs: grass-swimming species, which generally have elongation of trunk and tail, and fossorial species, which generally have elongation of trunk and short tail. The aim of the present study was to investigate the existence of evolutionary relationships between ecology and morphological aspects like body elongation and limb reduction in species of neo-tropical lizard family Gymnophthalmidae, evaluating how these evolutionary changes affect locomotor performance.
20

Locomotor Plasticity of an Amphibious Fish (Polypterus senegalus)

Lutek, Keegan 28 July 2022 (has links)
Animals control locomotion through unpredictable and complex habitats using a single locomotor control system. Because of the disparate physical mechanics of different environments, behavioural plasticity, based on the complex interplay of sensory feedback and environmental constraints, is likely essential for animals moving across environments. However, few studies have investigated neuromuscular control across different environments. To fill this gap, I make use of Polypterus senegalus to address four primary objectives: (1) to explore the extent of neuromuscular plasticity across environmental gradients (viscosity and water depth), (2) to generate and test hypotheses about paramount signals for this neuromuscular plasticity, (3) to determine the neuromuscular underpinnings of locomotor transitions, and (4) to determine the neuromuscular control of developmental behavioural plasticity in novel environments. I measured the kinematic and muscle activity response of P. senegalus to gradual changes in environment forces using gradients of water viscosity and water depth. I then used a semi-intact preparation to investigate the existence and role of the mesencephalic locomotor region, a brain region that controls locomotor speed and mode in other species, for neuromuscular control in P. senegalus. Finally, I used chronic terrestrial acclimation and exercise to determine the neuromuscular underpinnings of behavioural and morphological plasticity previously seen in P. senegalus reared in a terrestrial environment. I found that in high viscosity environments, P. senegalus maintain routine swimming speed using a swimming-like muscle activity pattern with increased effort in the posterior body and the pectoral fin to generate exaggerated swimming kinematics. These results suggest that sensory feedback is essential to accommodating this novel environment. I then demonstrated that axial red muscle always carried an anterior-to-posterior wave of muscle activity in a series of discrete water depths across the aquatic-terrestrial transition. Thus, discrete changes in axial kinematics and pectoral fin coordination across this transtion are likely the result of sensory feedback and mechanical constraints of the environment. I then performed the first experiments searching for the mesencephalic locomotor region in P. senegalus and demonstrated the presence of a putative mesencephalic locomotor region that controls the frequency of swimming-like movements but does not appear to control pectoral fin movements or the transition to walking. Finally, I exposed P. senegalus to chronic terrestrial acclimation and exercise. My results suggested that while both terrestrial acclimation and exercise generate behavioural plasticity, the former results in a larger plastic repsonse. Subtle changes in the duration and timing of pectoral fin muscle activity helped reduce friction between the body and pectoral fin and the substrate below, potentially resulting in the more “effective” walking gait developed by terrestrial acclimated fish. My thesis therefore sheds light on the essential interplay of sensory feedback and mechanical constraint for generating behavioural plasticity on acute and chronic timescales, highlights the potential value of such plasticity for organismal performance and evolution, and develops study systems and experimental frameworks for further investigating the nature of plastic locomotor control in amphibious fish.

Page generated in 0.0459 seconds