230 resultados para Lynx canadensis


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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O joelho, por suas características anatômicas e freqüente instabilidade e exposição as lesões tem o quadríceps como importante músculo a ser desenvolvido quanto ao seu trofismo e força. Composto de quatro porções distintas estas podem gerar diferentes vetores de força que podem ter relações diretas com o recrutamento de unidades motoras. O posicionamento articular, a conseqüente modificação do comprimento muscular e a intensidade da contração podem influenciar o desenvolvimento da força do quadríceps. Dentre as contrações relacionadas ao maior recrutamento de unidades motoras com o intuito do desenvolvimento de força está a contração isométrica. Dentre as contrações musculares, as isométricas têm sido frequentemente indicadas para aumentar a força e estabilidade articular em sessões de treinamento e reabilitação. Pelo exposto, o objetivo do estudo foi analisar os músculos vasto medial (VM) e vasto lateral (VL) por meio da eletromiografia de superfície durante 15s de contração isométrica a 20%, 30%, 40% e 50% da contração isométrica voluntária máxima – CIVM com o joelho a 90 graus. Foram utilizados eletrodos de superfície bipolar de Ag/AgCl, posicionados nos músculos VM e VL, um módulo de aquisição de sinais biológicos (Lynx) calibrado com ganho de 1000vezes, filtro de passa alta de 20Hz e de passa baixa de 500Hz. Uma célula de carga foi acoplada perpendicularmente à cadeira de teste especialmente desenvolvida para o estudo e utilizado uma indicador digital para retorno visual. Na análise estatística utilizou-se teste de Friedman e teste de Wilcoxon, e adotou-se nível de significância de p<0,05. Verificou-se que os músculos VM e VL foram semelhantes entre si, e entre as cargas, houve diferença significante entre as cargas de 20% e 40%, 20% e 50%, e 30% e 50% para ambos os músculos, com maior atividade nas cargas de 40% e 50% CVM... (Resumo completo, clicar acesso eletrônico abaixo)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Objetivo: O presente estudo buscou um indicador de classificação de presença de dor lombar baseado no tempo de resistência isométrica e em variáveis eletromiográficas. Material e Métodos: Para tanto participaram do presente estudo 40 voluntários do gênero masculino, os quais foram divididos em dois grupos de 20 voluntários, a saber: grupo sem dor lombar e grupo com dor lombar. Para a captação dos sinais eletromiográficos foram utilizados eletrodos de superfície descartáveis passivos de contato bipolar de Ag/AgCl conectados a um pré-amplificador de ganho de 20 vezes. A distância intereletrodos foi fixa em 20mm. Os eletrodos foram dispostos bilateralmente sobre os músculos longuíssimo do tórax, iliocostal lombar e multífido lombar. Foi utilizado um módulo de aquisição de sinais biológicos de 8 canais no qual foram conectados os eletrodos. Para a aquisição dos sinais foi utilizado um software específico (Aqdados 7-Lynx®) com a freqüência de amostragem calibrada em 2000 Hz. Com os equipamentos preparados e os eletrodos conectados os voluntários realizaram o teste de Sorensen, o qual consiste em sustentar o peso do tronco, em posição horizontal, até a exaustão voluntária. Para a análise dos sinais eletromiográficos foram utilizadas rotinas específicas em ambiente MatLab (MathWorks®). Neste software foi obtida a atividade eletromiográfica dos músculos selecionados durante o teste de contração isométrica até a exaustão para a determinação dos valores de root means quare (RMS) em pacotes de 1s a cada 0.5s (overlap). De cada espectro foram determinados os valores de frequência mediana (FM) e frequência média (Fmed) do sinal. Com a RMS, FM e Fmed foram obtidos também os valores de Razão ML/LT, Razão ML/IL e Razão IL/LT para cada variável. Com isto, os valores de RMS, FM e Fmed, juntamente com os valores de Razão ML/LT, Razão ML/IL e Razão IL/LT de cada variável, foram associados com o tempo...

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Stress hormones in Rocky Mountain bighorn sheep (Ovis canadensis canadensis), produced in response to environmental changes, road development, or high population density, may impact their immune systems to a threshold level that predisposes them to periodic, large-scale mortality. We compared the stress response to a novel environmental situation and repeated handling between bighorn sheep born and raised in captivity (CR) and bighorn sheep born in the wild (WC) and brought into captivity. We measured plasma epinephrine, norepinephrine, cortisol, and fecal glucocorticoid metabolites (FGM). Three weeks after each group’s arrival we used a one-time drop-net event to elicit an acute stress response, and we collected blood samples from each sheep over 35 minutes, as well as one fecal sample. We collected blood and fecal samples from both groups on 7 other occasions over the subsequent 6 months. We also collected fecal samples from the pen at approximately 24-hour intervals for 3 days following every handling event to monitor the stress response to handling. We found that CR sheep had a stronger autonomic nervous system response than WC sheep, as measured by epinephrine and norepinephrine levels, but we found a very similar hypothalamic–pituitary–adrenal axis (HPA) response, measured by cortisol levels, to the acute stress event of a drop-net restraint. We also found that once the WC sheep had acclimated, as indicated by the return to the initial baseline FGM levels within 12 weeks, the CR and WC groups’ HPA responses to sampling events were not significantly different from one another. Fecal samples can provide a noninvasive mechanism for managers to monitor baseline FGM for a given herd. Using long-term monitoring of FGM rather than values from a single point in time may allow managers to correlate these levels to outside influences on the herd and better understand the impacts of management changes, population density, or increased human developments on the health of the sheep population.

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In the mid-1820s, Anglo-American fur trappers, known as "mountain men," entered Arizona and began trapping beaver (Castor canadensis). In Arizona there have been a number of famous mountain men such as Sylvester and James Pattie, Ewing Young, Jededia Smith, and Bill Williams who trapped along the waterways in northern and southern Arizona. Although the heyday of mountain men lasted only a few decades due to a population decline of beaver, management of these animals continues to this day. The purpose of managing beavers shifted from monetary gain to controlling wildlife damage. During the late 1900s, beaver were still widely distributed in limited numbers throughout much of the state. We provide a historical overview of beaver management in Arizona with emphasis on the mountain men, recreational trapping, wildlife damage management, and beaver research in Arizona.

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Urban populations of Canada geese (Branta canadensis) cause considerable problems when large numbers congregate in parks, playing fields, and backyards. In most cases, geese are drawn to these sites to feed on the lawns. I tested whether geese have feeding preferences for different grass species. Captive Canada geese preferred Kentucky bluegrass (Poa pratensis) and disliked tall fescue (Festuca arundinaceae) over colonial bentgrass (Agrostis tenuis cv. Highland), perennial ryegrass (Lolium perenne), and red fescue (Festuca rubra). They refused to eat some other ground covers such as pachysandra (Pachysandra terminalis) and English ivy (Hedera helix). These results suggest that goose numbers at problem sites could be reduced by changing the ground cover. I also compared the characteristics of foraging sites used by geese to other foraging sites that geese avoided. Occupied sites were more open so that geese had clearer visibility and greater ease in taking off and landing. This suggests that goose numbers at problem sites also could be reduced by planting tall trees to make it harder for the geese to fly away, and planting bushes and hedges to obstruct a goose's visibility.

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Auxyn type herbicides such as dicamba and 2,4-D are alternative herbicides that can be used to control glyphosate-resistant hairy fleabane. With the forthcoming possibility of releasing dicamba-resistant and 2,4-D-resistant crops, use of these growth regulator herbicides will likely be an alternative that can be applied to the control of glyphosate resistant hairy fleabane (Conyza bonariensis). The objective of this research was to model the efficacy, through dose-response curves, of glyphosate, 2,4-D, isolated dicamba and glyphosate-dicamba combinations to control a brazilian hairy fleabane population resistant to glyphosate. The greenhouse dose-response studies were conducted as a completely randomized experimental design, and the rates used for dose response curve construction were 0, 120, 240, 480, 720 and 960 ga.i. ha(-1) for 2,4-D, dicamba and the dicamba combination, with glyphosate at 540 g a. e. ha(-1). The rates for glyphosate alone were 0, 180, 360, 540, 720 and 960 g a. e. ha(-1). Herbicides were applied when the plants were in a vegetative stage with 10 to 12 leaves and height between 12 and 15 cm. Hairy fleabane had low sensitivity to glyphosate, with poor control even at the 960 g a. e. ha(-1) rate. Dicamba and 2,4-D were effective in controlling the studied hairy fleabane. Hairy fleabane responds differently to 2,4-D and dicamba. The combination of glyphosate and dicamba was not antagonistic to hairy fleabane control, and glyphosate may cause an additive effect on the control, despite the population resistance.

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From September 2005 to December 2006, in order to define the prevalence of Helicobacter pullorum in broiler chickens, laying hens and turkey, a total of 365 caecum contents of animals reared in 76 different farms were collected at the slaughterhouse. A caecum content of a ostrich was also sampled. In addition, with the aim of investigating the occurrence of H. pullorum in humans, 151 faeces were collected at the Sant’Orsola-Malpighi University Hospital of Bologna from patients suffering of gastroenteritis. A modified Steele–McDermott membrane filter method was used. Gram-negative curved rod bacteria were preliminary identified as H. pullorum by a PCR assay based on 16S rRNA, then subjected to a RFLP-PCR assay to distinguish between H. pullorum and H. canadensis. One isolate from each farm was randomly selected for phenotypic characterization by biochemical methods and 1D SDSPAGE analysis of whole cell proteins profiles. Minimum Inhibitory Concentration (MIC) for seven different antibiotics were also determined by agar dilution method. Moreover, to examine the intraspecific genomic variability, two strains isolated from 17 different farms were submitted to genotyping by Pulse-Field Gel Electrophoresis (PFGE). In order to assess the molecular basis of fluorquinolone resistance in H. pullorum, gyrA of H. pullorum CIP 104787T was sequenced and nucleotide sequences of the Quinolone Resistance Determining Region (QRDR) of a total of 18 poultry isolates, with different MIC values for ciprofloxacin and nalidixic acid, were compared. According to the PCR and PCR-RFLP results, 306 out of 366 animals examined were positive for H. pullorum (83,6%) and 96,1% of farms resulted infected. All positive samples showed a high number of colonies (>50) phenotipically consistent with H. pullorum on the first isolation media, which suggests that this microrganism, when present, colonizes the poultry caecum at an elevate load. No human sample resulted positive for H. pullorum. The 1D SDS-PAGE whole protein profile analysis showed high similarity among the 74 isolates tested and with the type strain H. pullorum CIP 104787T. Regarding the MIC values, a monomodal distribution was found for ampicillin, chloramphenicol, gentamicin and nalidixic acid, whereas a bimodal trend was noticed for erythromycin, ciprofloxacin and tetracycline (indicating an acquired resistance for these antibiotics). Applying the breakpoints indicated by the CSLI, we may assume that all the H. pullorum tested are sensitive only to gentamicin. The intraspecific genomic variability observed in this study confirm that this species don’t have a clonal population structure, as motioned by other autors. The 2490 bp gyrA gene of H. pullorum CIP104787T with an Open Reading Frame (ORF) encoding a polypeptide of 829 amino acids was for the first time sequenced and characterized. All ciprofloxacin resistant poultry isolates showed ACA®ATA (Thr®Ile) substitution at codon 84 of gyrA corresponding to codons of gyrA 86, 87 and 83 of the Campylobacter jejuni, H. pylori and Escherichia coli, respectively. This substitution was functionally confirmed to be associated with the ciprofloxacin resistant phenotype of poultry isolates. This is the first report of isolation of H. pullorum in turkey and in ostrich, indicating that poultry species are the reservoir of this potential zoonotic microorganisms. In order to understand the potential role as food-borne human pathogen of H. pullorum, further studies must be carried on.

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This thesis assesses relationships between vegetation and topography and the impact of human tree-cutting on the vegetation of Union County during the early historical era (1755-1855). I use early warrant maps and forestry maps from the Pennsylvania historical archives and a warrantee map from the Union County courthouse depicting the distribution of witness trees and non-tree surveyed markers (posts and stones) in early European settlement land surveys to reconstruct the vegetation and compare vegetation by broad scale (mountains and valleys) and local scale (topographic classes with mountains and valleys) topography. I calculated marker density based on 2 km x 2 km grid cells to assess tree-cutting impacts. Valleys were mostly forests dominated by white oak (Quercus alba) with abundant hickory (Carya spp.), pine (Pinus spp.), and black oak (Quercus velutina), while pine dominated what were mostly pine-oak forests in the mountains. Within the valleys, pine was strongly associated with hilltops, eastern hemlock (Tsuga canadensis) was abundant on north slopes, hickory was associated with south slopes, and riparian zones had high frequencies of ash (Fraxinus spp.) and hickory. In the mountains, white oak was infrequent on south slopes, chestnut (Castanea dentata) was more abundant on south slopes and ridgetops than north slopes and mountain coves, and white oak and maple (Acer spp.) were common in riparian zones. Marker density analysis suggests that trees were still common over most of the landscape by 1855. The findings suggest there were large differences in vegetation between valleys and mountains due in part to differences in elevation, and vegetation differed more by topographic classes in the valleys than in the mountains. Possible areas of tree-cutting were evenly distributed by topographic classes, suggesting Europeans settlers were clearing land and harvesting timber in most areas of Union County.

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To date, investigations of genetic diversity and the origins of domestication in sheep have utilised autosomal microsatellites and variation in the mitochondrial genome. We present the first analysis of both domestic and wild sheep using genetic markers residing on the ovine Y chromosome. Analysis of a single nucleotide polymorphism (oY1) in the SRY promoter region revealed that allele A-oY1 was present in all wild bighorn sheep (Ovis canadensis), two subspecies of thinhorn sheep (Ovis dalli), European Mouflon (Ovis musimon) and the Barbary (Ammontragis lervia). A-oY1 also had the highest frequency (71.4%) within 458 domestic sheep drawn from 65 breeds sampled from Africa, Asia, Australia, the Caribbean, Europe, the Middle East and Central Asia. Sequence analysis of a second locus, microsatellite SRYM18, revealed a compound repeat array displaying fixed differences, which identified bighorn and thinhorn sheep as distinct from the European Mouflon and domestic animals. Combined genotypic data identified 11 male-specific haplotypes that represented at least two separate lineages. Investigation of the geographical distribution of each haplotype revealed that one (H6) was both very common and widespread in the global sample of domestic breeds. The remaining haplotypes each displayed more restricted and informative distributions. For example, H5 was likely founded following the domestication of European breeds and was used to trace the recent transportation of animals to both the Caribbean and Australia. A high rate of Y chromosomal dispersal appears to have taken place during the development of domestic sheep as only 12.9% of the total observed variation was partitioned between major geographical regions.

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While hemoplasma infections in domestic cats are well studied, almost no information is available on their occurrence in wild felids. The aims of the present study were to investigate wild felid species as possible reservoirs of feline hemoplasmas and the molecular characterization of the hemoplasma isolates. Blood samples from the following 257 wild felids were analyzed: 35 Iberian lynxes from Spain, 36 Eurasian lynxes from Switzerland, 31 European wildcats from France, 45 lions from Tanzania, and 110 Brazilian wild felids, including 12 wild felid species kept in zoos and one free-ranging ocelot. Using real-time PCR, feline hemoplasmas were detected in samples of the following species: Iberian lynx, Eurasian lynx, European wildcat, lion, puma, oncilla, Geoffroy's cat, margay, and ocelot. "Candidatus Mycoplasma haemominutum" was the most common feline hemoplasma in Iberian lynxes, Eurasian lynxes, Serengeti lions, and Brazilian wild felids, whereas "Candidatus Mycoplasma turicensis" was the most prevalent in European wildcats; hemoplasma coinfections were frequently observed. Hemoplasma infection was associated with species and free-ranging status of the felids in all animals and with feline leukemia virus provirus-positive status in European wildcats. Phylogenetic analyses of the 16S rRNA and the partial RNase P gene revealed that most hemoplasma isolates exhibit high sequence identities to domestic cat-derived isolates, although some isolates form different subclusters within the phylogenetic tree. In conclusion, 9 out of 15 wild felid species from three different continents were found to be infected with feline hemoplasmas. The effect of feline hemoplasma infections on wild felid populations needs to be further investigated.

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Tsuga canadensis (eastern hemlock) is a highly shade-tolerant, late-successional, and long-lived conifer species found throughout eastern North America. It is most often found in pure or nearly pure stands, because highly acidic and nutrient poor forest floor conditions are thought to favor T. canadensis regeneration while simultaneously limiting the establishment of some hardwood species with greater nutrient requirements. Once a common species, T. canadensis is currently experiencing widescale declines across its range. The hemlock woolly adelgid (Adelges tsugae) is decimating the population across its eastern distribution. Across the Upper Great Lakes region, where the adelgid is currently being held at bay by cold winter temperatures, T. canadensis has been experiencing failures in regeneration attributed, in part, to herbivory by white-tailed deer (Odocoileus virginianus). Deer utilize T. canadensis stands as winter habitat in areas of high snow depth. Tsuga canadensis, once a major component of these forests, currently exists at just a fraction of its pre-settlement abundance due to historic logging and contemporary forest management practices, and what remains is found in small remnant patches surrounded by second- and third-growth deciduous forests. The deer population across the region, however, is likely double that of pre-European settlement times. In this dissertation I explore the relationship between white-tailed deer use of T. canadensis as winter habitat and the effect this use is having on regeneration and forest succession. For this research I quantified stand composition and structure and abiotic variables of elevation and snow depth in 39 randomly selected T. canadensis stands from across the western Upper Peninsula of Michigan. I also quantified composition and the configuration of the landscapes surrounding these stands. I measured relative deer use of T. canadensis stands as pellet group piles deposited in each stand during each of three consecutive winters, 2005-06, 2006-07, and 2007-08. The results of this research suggest that deer use of T. canadensis stands as winter habitat is influenced primarily by snow depth, elevation, and the composition and configuration of the greater landscapes surrounding these stands. Specifically, stands with more heterogeneous landscapes surrounding them (i.e., a patchy mosaic of conifer, deciduous, and open cover) had higher relative deer use than stands surrounded by homogenous deciduous forest cover. Additionally, the intensity of use and the number of stands used was greater in years with higher average snow depth. Tsuga canadensis regeneration in these stands was negatively associated with deer use and Acer saccharum (sugar maple) basal area. Of the 39 stands, 17 and 22 stands had no T. canadensis regeneration in small and large sapling categories, respectively. Acer saccharum was the most common understory tree species, and the importance of A. saccharum in the understory (stems < 10 cm dbh) of the stands was positively associated with overstory A. saccharum dominance. Tsuga canadensis establishment was associated with high-decay coarse woody debris and moss, and deciduous leaf litter inputs in these stands may be limiting access to these important microsites. Furthermore, A. saccharum is more tolerant to the effects of deer herbivory than T. canadensis, giving A. saccharum a competitive advantage in stands being utilized as winter habitat by deer. My research suggests that limited microsite availability, in conjunction with deer herbivory, may be leading to an erosion in T. canadensis patch stability and an altered successional trajectory toward one of A. saccharum dominance, an alternately stable climax species.

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Throughout the Upper Great Lakes region, alterations to historic disturbance regimes have influenced plant community dynamics in hemlock-hardwood forests. Several important mesic forest species, eastern hemlock (Tsuga canadensis), yellow birch (Betula alleghaniensis), eastern white pine (Pinus strobus), and Canada yew (Taxus canadensis), are in decline due to exploitive logging practices used at the turn of the 20th century and the wave of intense fires that followed. Continued regeneration and recruitment failure is attributed to contemporary forest management practices and overbrowsing by white-tailed deer (Odocoileus virginianus). Therefore, I examined the influence of two concurrent disturbances, overstory removal and herbivory, on plant community dynamics in two hemlock-hardwood forests. I measured the post-disturbance regeneration response (herbaceous and woody species) inside and outside of deer exclosures in 20 artificial canopy gaps (50 – 450 m2) and monitored survival and growth for hundreds of planted seedlings. The results of this research show that interacting disturbances can play a large role in shaping plant community composition and structure in hemlock-hardwood forests. White-tailed deer herbivory homogenized the post-disturbance plant communities across the experimental gradient of gap areas, essentially making species compositions in small gaps “look like” those in large gaps. Deer browsing also influenced probability of survival for planted Canada yew cuttings; all else being equal an individual was nearly seven times more likely to survive if protected from herbivory (P < 0.001). In contrast, the ability of sugar maple (Acer saccharum) to persist under high levels of herbivory and respond rapidly to overstory release appears to be related to the presence of stem layering(i.e., portions of below-ground prostrate stem). Layering occurred in 52% of excavated saplings (n = 100) and was significantly associated with increased post-disturbance height growth. Understory light was also important to planted seedling establishment and height growth. Higher levels of direct under-canopy light negatively impacted survival for shade-tolerant hemlock and Canada yew, while an increase in diffuse light was linked to a higher probability of survival for yellow birch and height growth for hemlock and Canada yew. Increases in white pine height growth were also significantly associated with a decrease in canopy cover.

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A subset of forest management techniques, termed ecological forestry, have been developed in order to produce timber and maintain the ecological integrity of forest communities through practices that more closely mirror natural disturbance regimes. Even though alternative methods have been described and tested, these approaches still need to be established and analyzed in a variety of geographic regions in order to calibrate and measure effectiveness across different forest types. The primary objective of this research project was to assess whether group selection combined with legacy-tree retention could enhance mid-tolerant tree recruitment in a late-successional northern hardwood forest. In order to evaluate a novel alternative regeneration technique, 49 group-selection openings in three size classes were created in 2003 with a biological legacy tree retained in the center of each opening. Twenty reference sites, managed using single-tree selection, were also analyzed for comparison. The specific goals of the project were to: 1) determine the fate and persistence of the openings and legacy trees 2) assess the understory response of the group-selection openings versus the single-tree selection reference sites, and 3) evaluate the spatial patterns of yellow birch (Betula alleghaniensis Britt.) and eastern hemlock (Tsuga canadensis (L.) Carr.) in the group-selection openings. The results from 8-9 years post-study implementation and the changes that have occurred between 2004/5 and 2011/12 are discussed. The alternative regeneration technique developed and assessed in this study has the potential to enrich biodiversity in a range of forest types. Projected group-selection opening persistence rates ranged from 41-91 years. Openings from 500-1500 m2 are predicted to persist long enough for mid-tolerant tree recruitment. The legacy trees responded well to release and experienced a low mortality rate. Yellow birch (the primary shade mid-tolerant tree in the study area) densities increased with opening size. Maples surpassed all other species in abundance. In the sapling layer, sugar maple (Acer saccharum Marsh.) was 2 to over 300 times more abundant in the group-selection openings and 2 to 3 times more abundant in the references sites than all other species present. Red maple (Acer rubrum L.) was the second most abundant species present in the openings and reference sites. Spatial patterns of yellow birch and eastern hemlock in the openings were mostly aggregated. The southern edges of the largest openings contained the highest magnitude of yellow birch and eastern hemlock per unit area. Continued monitoring and additional treatments will likely be necessary in order to ensure underrepresented species successfully reach maturity.