Spelling suggestions: "subject:"codent"" "subject:"podent""
51 |
Nocturnal rodent populations and associated vegetation with implications of human use at Saguaro National Monument, ArizonaDuncan, Douglas Keith, 1960- January 1989 (has links)
I obtained densities of nocturnal rodents in the saguaro (Carnegiea gigantea) forest of Saguaro National Monument, Arizona with live trapping techniques, in 1984 and 1985. I sampled vegetation density, percent cover, and foliage height diversity. My objective was to determine if humans influenced nocturnal rodents and their habitat. Rodent populations and vegetation were analyzed through 2-way analysis of variance. Few significant differences were determined for rodent numbers between experimental and control plots. My findings show that minimal impact has occurred on rodent populations and on vegetation by humans in Saguaro National Monument.
|
52 |
Smågnagare I Boreonemorala Habitat I Mellansverige : Artsammansättning Och PopulationskonditionTooke, Daniel January 2017 (has links)
Microtine rodents are a key component in the boreal ecosystem. Due to unique yearly fluctuation in population numbers, in addition to their central placement within boreal foodwebs, microtine rodent population dynamics control a wide variety of predator populations. Despite their grouping as microtine rodents, many individual species exhibit very different cycles, such as voles and lemmings. As such, the identification of species composition and ratio in each given habitat is of utmost importance. The purpose of this study was to compare the composition of species of small rodents between four different habitats (grassland, wetland, spruce dominated forest and pine dominated forest) and to statistically analyze if the different biotopes hosted significant differences in species composition. The project also aimed to examine differences in weight and numbers between populations of the same species in the different biotopes. To accomplish this, rodents were captured using non-lethal traps, and the resulting data was analyzed using RxC tables and ANOVA. The species captured were A. sylvaticus, C. glareolus and M. agrestis. The result of the analysis showed that the only difference in species composition existed between the grassland habitat and the rest. In addition, there existed no difference between different populations of A. sylvaticus in regards to weight. However, a difference was found between the populations of C.glareolus, with the individuals inhabiting spruce dominated forest being larger than those found in other habitats.
|
53 |
Neuroprotective and Restorative Potential of Remote Ischemic Conditioning Following StrokeDykes, Angela 26 June 2019 (has links)
Remote ischemic conditioning (RIC) is a noninvasive procedure where blood flow to a limb is repetitively reduced, sometimes called an “exercise memetic”. RIC delivered before (pre-RIC) or after (post-RIC) stroke is reportedly neuroprotective in preclinical stroke models. A review of the preclinical RIC literature revealed that studies almost exclusively use male subjects and a single stroke model (MCAO) that produces a large injury (~34% of hemisphere). To improve clinical translation, efficacy should be demonstrated in multiple stroke models and both sexes. Furthermore, the restorative potential of RIC (delivered past the neuroprotection window) to improve stroke recovery remains to be investigated. In male and female Sprague-Dawley rats (n=129) a standardized session (5min inflation, 5min deflation, 4 repetitions) of RIC was delivered using a pressurized cuff on the hindlimb. RIC was either delivered once 18h before, once 4hr acutely after or daily for 28 days beginning day 5 after endothelin-1 (ET-1) stroke. Infarct volumes were assessed 24hrs after stroke using MRI. To determine if RIC efficacy varied across stroke size, a hierarchical cluster analysis was used to divide rats into subgroups based on stroke size (small/large). RIC was effective in ET-1 which produced smaller strokes (“small”:5.2%, “large”:18.0% of hemisphere) than MCAO (~34%). This is more comparable to injury sizes seen clinically (4.5-14.0%). “Small” (42±4mm3) strokes were reduced by 39% (p=0.010, d=0.29) and “large” (146±8mm3) strokes were reduced by and 35% (p<.00001, d=1.41). Pre-RIC reduced infarct volume by 41% (p=<0.0001, d=0.92) versus 29% (p=0.009, d=0.43) in post-RIC. Interestingly, RIC is more effective in males, with double the infarct volume reduction of 46% (p<0.0001, d=0.94) compared with 23% (p=0.013, d=0.42) in females. Although RIC did not show restorative potential to improve motor stroke recovery, RIC is neuroprotective now with stronger clinically relevant evidence. RIC is effective across stroke models, stroke sizes and sex. Application of RIpreC to prevent stroke following a transient ischemic attack or recurrent stroke (especially in males with “large" strokes) would have the greatest potential.
|
54 |
Placentação e descrição morfológica do sistema reprodutor feminino em Coendou prehensilis (Porco-espinho Caixeiro) / Placentation and morphological description of female reproductive system in Coendou prehensilis (Prehensile-tailed porcupine)Cury, Fabio Sergio 19 December 2016 (has links)
A preservação de espécies silvestres brasileiras é baseada no conhecimento, distribuição e comportamento tanto no meio ambiente natural, quanto em cativeiro, sendo assim, existe uma grande importância tratando-se da descrição reprodutiva das espécies estudadas visando sempre à perpetuação. Este estudo possui foco no sistema reprodutivo feminino, relacionando ao processo de placentação, além da evolução quanto à posição filogenética dos mamíferos, descrevendo a morfologia da placenta, barreira placentária em delimitação da evolução filogenética desse órgão em animais da espécie Coendou prehensilis. O Coendou prehensilis, chamado popularmente de porco-espinho caixeiro ou ouriço-caixeiro, é um roedor herbívoro que vive geralmente em árvores de florestas tropicais desde o México até a América do sul, é um mamífero que pode pesar de 2 a 5 kg e medir de 30 a 60 cm de comprimento. Para o estudo foram utilizados 07 animais (2 gestantes e 5 não gestantes) que vieram a óbito por ataques de cães e atropelamentos em estradas, animais estes, devidamente regularizados pelo ICMBio. Foram realizadas as técnicas macroscópicas, descrevendo o formato, vascularização e biometria dos órgãos reprodutores e placenta da espécie em questão, além de microscopia de luz, imunohistoquimica (vimentina 1:200, PCNA 1:700 e citoqueratina 1:400), microscopia eletrônica de varredura e microscopia eletrônica de transmissão, a fim de caracterizar o tipo e a barreira placentária e descrever relações materno-fetais na placenta. Os ovários possuem formato elipsóide, cor amarelada, mostrando-se achatados dorso-ventralmente e são relativamente grandes, com variações de parede lisa a mais áspera, apresentando diferentes fases foliculares. As tubas uterinas são tubulares, cilíndricas e tortuosas. Estendem-se lateralmente, curvando-se craniocaudalmente sobre os ovários. Não são contínuas em espessura e forma, sendo possível distinguir infundíbulo, ampola e istmo. O útero é do tipo bicórneo em forma de Y possuindo dois longos cornos cilíndricos, ao longo de seu lúmen não apresenta um septo mediano. A vagina possui epitélio estratificado escamoso não queratinizado, com pregas longitudinais, sendo o número de pregas variável assim como sua espessura. A vulva possui diferença de cor tegumentar dos grandes lábios em relação à rima, sendo o pequeno espaço entre a vulva e o ânus o indicativo para o dimorfismo sexual do animal. O clitóris está situado na porção ventral da rima, atrás da comissura labial superior, sendo não visível. A placenta é do tipo corioalantóica, discoidal, labiríntica de padrão lobular, correspondendo a principal região para trocas materno-fetal sendo identificados vasos fetais por endotélio vimentina - positivo, em contraste com os espaços de sangue materno. Células gigantes sinusoidais foram identificadas no labirinto e próximo a decídua. O saco vitelino visceral é composto por células cúbicas da endoderme, uma camada de mesênquima rica em vasos e mesotélio. Possui uma subplacenta e apresenta relação materno-fetal do subtipo hemomonocorial, além de um saco vitelino presente até o final da gestação. Com os resultados da análise estrutural do material esperamos poder contribuir melhorando assim os dados sobre os aspectos reprodutivos da espécie, colaborando em outras futuras pesquisas, e gerando uma base comparativa para mamíferos sul-americanos semelhantes e pouco estudados em nosso território. / The preservation of wild Brazilian species is based on knowledge, distribution, behavior both in the natural environment and in captivity, therefore, there is a great importance in the case of reproductive description of the species studied always aiming the perpetuation. This study has focused on the uterine detailing and their reproductive whole, related to placentation process, in addition to evolution as the phylogenetic position of mammals, describing the morphology of the placenta, placental barrier in delimitation of phylogenetic evolution of this organ in animals of the species Coendou prehensilis. The C. prehensilis, popularly called porcupine clerk or porcupine, is an herbivorous rodent that usually lives in tropical forest trees from Mexico to South America, is a mammal that can weigh 2-5 pounds and measure 30 to 60 centímeters. For the study, 07 animals (2 pregnant and 5 non-pregnant) were used, all animals died by dog attacks and trampling on roads, the research was regularized by IBAMA. Macroscopic techniques were used describing the format, vascularization and biometry of the reproductive organs and placenta of the species in question, besides light microscopy, immunohistochemistry (vimentin 1: 200, PCNA 1: 700 and cytokeratin 1: 400), electron microscopy scanning and transmission electron microscopy to characterize the placental barrier and to describe maternal-fetal relations in the placenta. The ovaries are ellipsoid in shape, yellow in color and are flattened dorsi-ventrally and are relatively large, with smooth wall variations presenting different follicular phases. The uterine tubes are tubular, cylindrical and tortuous. They extend laterally, curving craniocaudally on the ovaries. They are not continuous in thickness and shape, being possible to distinguish infundibulum, ampule and isthmus. The uterus is bicornuous in a \"Y\" format with two long cylindrical horns, along its lumen does not present a median septum. The vagina has non-keratinized squamous stratified epithelium, with longitudinal folds, the number of folds is variable as well as its thickness. The vulva has a difference in tegumentary color of the big lips in relation to the rhyme. The clitoris is located in the ventral portion of the rhyme behind the upper labial commissure and is not visible. The placenta is chorioallantoic, zoonary, discoid, labyrinthine type of lobular pattern, corresponding to the main region for maternal-fetal exchanges. And fetal vessels were identified by vimentin - positive endothelium, in contrast to the maternal blood spaces. Giant sinusoidal cells were identified in the labyrinth and close to decidua. The visceral yolk sac is composed of cubic cells of the endoderm, a layer of mesenchyme rich in pots and mesothelium. It has a subplacenta and presents a maternal-fetal relationship of the hemomonochorial subtype, besides a yolk sac present until the end of gestation. With the results of the structural analysis of the material, we hope to contribute to improve the data on the reproductive aspects of the species, collaborating in other future research, and generating a comparative base for similar South American mammals in our territory.
|
55 |
Biologia da reprodução do macho de Viscacha (Lagostomus Maximus) - uma parceria entre Brasil e Argentina para integração da biotecnologia da reprodução em animais ameaçados / Reproductive biology of male viscacha (Lagostomus maximus)-Partnership between Brazil and Argentina for the integration of biotechnology in breeding of endangered animalsPieri, Naira Caroline Godoy 10 November 2011 (has links)
Atualmente muitos são os estudos com animais silvestres, no entanto, pouco se sabe sobre os aspectos biológicos dos machos. Os Histricomorpha são uma subordem da ordem Rodentia, que representa 43% das 4629 espécies reconhecidas encontradas na classe Mammalia. Os roedores são animais que oferecem uma extraordinária variedade de adaptações ecológicas, suportando os mais diversos tipos de climas e altitudes, podendo com isso apresentar grande diversidade funcional, a viscacha é um roedor pertencente a esta subordem, e de grande importância para o ambiente em que habitam, pois, representam a base da cadeia alimentar. Por esta razão, esta pesquisa ter por objetivo descrever morfologicamente o aparelho reprodutor do macho de viscacha. Foram utilizados seis macho adultos de viscacha, realizou-se análise macro e de microscópia de luz, eletrônica e imunohistoquímicas do sistema reprodutor masculino, bem como a espermatogênese deste animal. Através das análises realizadas, a viscacha apresenta o aparelho reprodutor composto por um par de testículos, epidídimo e ducto deferente e as seguintes glândulas genitais acessórias: próstata, vesícula seminal e glândula bulbouretral. Estas estruturas são semelhantes às de outros roedores já descritos, como a Chinchila e Cutia. A análise espermatogênica demonstrou que esta exibe alterações significativas de seus parâmetros, em sincronia com o ambiente externo e o ciclo reprodutivo. Conclui-se, com os animais estudados, que a morfologia do aparelho reprodutor do L.maximus viscacha é semelhante aos demais roedores pertencentes à subordem dos Histricomorfos. / Many groups are focused their studies on wild animal reproductive biology. However little is still known about the male biology. The Histricomorpha is a suborder of the Rodentia order, which represents 43% of 4,629 recognized species found in the class of Mammalia. Rodents are animals that offer an extraordinary variety of ecological adaptations, supporting all kinds of climates and altitudes, and this may have vast functional diversity. The viscacha is a rodent animal that belongs to this suborder, and it has a great importance to the environment it inhabits, since they represent the base of the food chain. For this reason, this research aims to describe the morphology of the reproductive system of male viscacha. Six adult viscacha males were used for gross anatomy analysis, for light and electron microscopic analysis, and immunhistochemical analysis to describe the normal histology and spermatogenesis of the reproductive tract of adult male viscacha. The reproductive system of the male viscacha consists in a pair of testicles, epididymis and vas deferens and accessory genital glands following: prostate, seminal vesicles and bulbourethral gland. These structures are similar to those already described for other rodents such as Chinchilla and Agouti. The analysis of spermatogenesis suggested that the male viscacha is able to synchronize its spermatogenesis according to the environment, which the animal is inserted in, and its reproductive cycle. This study showed that the reproductive system of the viscacha (L.maximus) is morphologically similar to other rodents belonging to the suborder histricomorphas.
|
56 |
Rattus tanezumi in the upland rice terraces of Banaue, Philippines: demography, habitat use, crop damage and yield assessment.Miller, Rachel Weslie, Biological, Earth & Environmental Sciences, Faculty of Science, UNSW January 2007 (has links)
Rodents cause significant damage to agricultural crops throughout the world, including rice, the staple food for the increasing population of Southeast Asia. Little is known about the ecology of pest rodent species, resulting in much effort being concentrated on ineffective, time consuming control practices. This research was designed to understand the demography and habitat use of the major pest rodent (Rattus tanezumi) of the Banaue rice terraces in order to identify the most efficient time and location to undertake pest control. Rodent crop damage and associated yield loss was also assessed in order to provide information for a cost : benefit analysis of rodent control practices. And the beliefs, perceptions and practices of Banaue rice farmers were investigated to assist in identifying future compatible rodent control programs. Replicated cage trapping was undertaken for a twelve month period over the entire rice cropping season in two study sites in the Municipality of Banaue Philippines. The breeding season of R. tanezumi corresponded with periods of food availability from the transplanted to ripening stages of the rice crop. A non-breeding season occurred from the fallow to seedling stages. The distinct breeding season occurred within the rice fields and adjacent village and scrub habitats. Radio-tracked and spool-and-line tracked R. tanezumi moved from adjacent habitats into the rice field during the breeding season, and individuals persisted in all habitat types, including the rice field, during the fallow, nonbreeding season. Overall rice yield was significantly greater (43%) in areas where rodents were excluded by fencing compared to areas where rodents were not excluded. More rodent damage to rice tillers occurred at the booting than at the ripening stage of the rice crop. These results suggest that to prevent rodent damage, control should be undertaken at the end of the R. tanezumi non-breeding season (prior to transplanting), before rodent numbers multiply and crop damage occurs. Further, the cost-benefit analysis of non-chemical rodent control programs in Banaue, suggests that benefits accrue once yield loss is likely to exceed 5%.
|
57 |
Sigmodon hispidus in relation to vegetation in Belize District, BelizeBrier, John C. 03 June 2011 (has links)
Cotton rats, Sigmodon hispidus, were trapped and studied in Belize District, Belize, Central America from June 14, 1973 to July 13, 1973. Vegetation in the area was surveyed to determine height, extent of matting, and species composition. Comparisons were then made between vegetation and S. hispidus captures. A total of 48 S. hispidus,were captured, primarily in areas of tall and matted grass. S. hispidus appeared to be absent from areas of short grass.Reproduction, body size, sex ratio, parasites, and behavior of S. hispidus are discussed. Other mammals taken during the study included two specimens of Or_yzomys, fulvescens,, a species which had not previously been collected in Belize.Ball State UniversityMuncie, IN 47306
|
58 |
Mitigating Disuse Bone Loss: Role of Resistance Exercise and Beta-Adrenergic SignalingSwift, Joshua Michael 2010 May 1900 (has links)
Mechanical loading is an integral component to maintaining bone mass during periods of disuse (i.e. bedrest or casting) or reduced weightbearing activity. Recent data has shown a direct relation between the sympathetic nervous system (SNS) and bone metabolism, however the underlying mechanisms responsible for this relationship are unknown. Furthermore, the role that beta adrenergic stimulation during disuse has on cancellous bone mass and microarchitecture have yet to be defined. The central hypothesis of this research is that resistance exercise and beta-1 adrenergic (Adrb1) receptor agonist administration attenuate disuse-associated reductions in metaphyseal bone during 28 days of rodent hindlimb unloading (HU).
Study one determined whether an eccentric- (ECC) or combined isometric+eccentric- (ISO+ECC) based contraction paradigm, engaged during hindlimb unloading (HU), mitigates losses in musculoskeletal mass and strength. Both simulated resistance training (SRT) protocols inhibited reductions in disuse-sensitive cancellous bone mass and maintained plantarflexor muscle strength.
Study two determined whether combining the anabolic effects of SRT with the anti-resorptive effects of alendronate (ALEN) during HU positively impacts cancellous bone in an additive or synergistic fashion. ALEN significantly inhibited the anabolic response of cancellous bone to SRT during HU.
Study three determined whether an Adrb1 receptor agonist (dobutamine; DOB) mitigates disuse-associated losses in bone mass and formation rate (BFR) during HU. DOB administration significantly blunted reductions in bone mineral density (vBMD) by maintaining cancellous BFR.
Study four determined if Adrb1 receptor agonist administration during HU results in an attenuation of osteocyte apoptosis within cancellous bone and whether this relates to a decrease in Bax/Bcl-2 mRNA content ratio (pro- and anti-apoptotic proteins). HU significantly increased cancellous bone osteocyte apoptosis and Bax/Bcl-2 mRNA content ratio, which was reduced by the administration of DOB.
Collectively, these are the first studies to assess the role of beta-1 adrenergic signaling and resistance exercise in mitigating disuse-induced loss of cancellous bone mass in rodents. The long term goals of this research are to understand the exact molecular mechanisms by which both Adrb1 signaling and high intensity resistance exercise provide beneficial bone effects during prolonged periods of disuse and to apply these findings to current osteoporosis research.
|
59 |
Microbial pathogen contamination in mouse gametes and embryosZhang, Lin, January 2008 (has links)
Thesis (M.S.)--University of Missouri-Columbia, 2008. / "May 2008" The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Includes bibliographical references.
|
60 |
Sonic Pest RepellentsAflitto, Nicholas, DeGomez, Tom 10 1900 (has links)
4 pp. / Commercially available sonic pest devices for use in residential applications have not been shown to be effective in scientific studies. For this reason, use of these devices is not advised to treat common pest problems. Although some researchers are developing sonic techniques that illustrate promise for very specific pests, these technologies are yet to be commercially available. As our understanding increases of how pest species receive and process sound, more relevant sonic devices may be developed. The allure of sound as a treatment for pests will remain into the future—motivated by the fact that if they are successful they will be more environmentally friendly and safer for humans.
|
Page generated in 0.0523 seconds