• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 37
  • 24
  • 5
  • 2
  • 2
  • 1
  • Tagged with
  • 78
  • 12
  • 11
  • 9
  • 8
  • 8
  • 7
  • 7
  • 7
  • 7
  • 6
  • 6
  • 6
  • 6
  • 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.
51

Lactational transfer of cadmium in rodents : CNS effects in the offspring /

Petersson Grawé, Kierstin, January 2003 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 4 uppsatser.
52

Ectoparasitos em preás (Galea spixii Wagler, 1831) cativos no Semiárido do Rio Grande do Norte, Brasil / Ectoparasites in guinea pigs (Galea spixii Wagler, 1831) captive in semiarid region of Rio Grande do Norte, Brazil

Pereira, Josivania Soares 20 May 2011 (has links)
Made available in DSpace on 2016-08-15T20:30:56Z (GMT). No. of bitstreams: 1 JosivaniaSP_DISSERT.pdf: 1747964 bytes, checksum: dc76ae1fd20c57376c8d1c909a447f10 (MD5) Previous issue date: 2011-05-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The wild rodents when bred in captivity may be affected by some infectious or parasitic diseases, which affects the health and welfare of these animals. Based on this, we aimed to work in order to identify the natural ectofauna cavy Galea spixii raised in conditions of captivity in the semi arid region of Rio Grande do Norte and study the behavior of the dynamics of the ectoparasitism more prevalent. The study was performed in 40 specimens adult male of G. spixii captives of Centro de Multiplicação de Animais Silvestres of the Universidade Federal Rural do Semi-Arid. The specimens were anesthetized and examined for ectoparasites during the research, in the months from March to October 2010. All guinea pigs studied were positive for ectoparasites, among them, Amblyomma sp. Demodex sp. and Gliricola quadrisetosa. The latter species was the most prevalent. By linking G. quadrisetosa with the dorsal and lateral body surface area of G. spixii, just in one of the correlations made, showed statistically significant differences (p <0.05), where we noted that the average number of lice recovered from different body regions was greater for female specimens. The climatic period did not influence the frequency of G. quadrisetosa recovered from animals (p> 0.05). From the ectofauna identified in the G. spixii we notify the Demodex sp. as first recorded in this rodent in semi arid conditions in Brazil. The data suggests that body area and the climate did not interfere in infra population of G. quadrisetosa found in G. spixii. / Os roedores silvestres quando criados em cativeiro podem ser acometidos por algumas doenças de natureza infecciosa ou parasitária, o que afeta a sanidade e bem-estar destes animais. Nesta linha, esse trabalho objetivou identificar a ectofauna natural do preá Galea spixii criado nas condições de cativeiro no semiárido do Rio Grande do Norte e estudar o comportamento da dinâmica parasitaria do ectoparasitismo mais prevalente. O estudo foi realizado em 40 espécimes machos adultos de G. spixii cativos do Centro de Multiplicação de Animais Silvestres da Universidade Federal Rural do Semi-Árido. Os exemplares foram anestesiados e examinados para busca dos ectoparasitos, durante os meses de março a outubro de 2010. Todos os preás estudados apresentaram resultados positivos para ectoparasitos, dentre os quais, Amblyomma sp., Demodex sp. e Gliricola quadrisetosa. A última espécie citada foi a de maior prevalência. Ao relacionar G. quadrisetosa com a área corporal dorsal e lateral de G. spixii, apenas uma das várias correlações feitas, apresentou diferença estatística significativa (p<0,05), na qual se observou que a média de piolhos recuperados nas distintas regiões corporais foi maior para exemplares fêmeas. O período climático não influenciou na frequência de G. quadrisetosa recuperada dos animais (p>0,05). Da ectofauna identificada em G. spixii, notifica-se Demodex sp. como primeiro registro neste roedor nas condições semiáridas do Brasil. Os dados sugerem que a área corporal e o período não interferiram na infrapopulação de G. quadrisetosa encontrada em G. spixii.
53

Diversidade de espécies, variação cariotípica e distribuição dos roedores da Chapada Diamantina, BA

Souza, Ana Lazar Gomes e 02 1900 (has links)
Submitted by Alberto Vieira (martins_vieira@ibest.com.br) on 2017-10-18T22:47:32Z No. of bitstreams: 1 633897.pdf: 13502617 bytes, checksum: 3ed829ad8ef2133cdafe46cf1bf47d48 (MD5) / Made available in DSpace on 2017-10-18T22:47:32Z (GMT). No. of bitstreams: 1 633897.pdf: 13502617 bytes, checksum: 3ed829ad8ef2133cdafe46cf1bf47d48 (MD5) Previous issue date: 2005-02 / CAPES / A Chapada Diamantina é um vasto platô montanhoso localizada no interior do estado da Bahia, com altitudes variando de 400 a 2000m. Nenhum trabalho sistemático sobre a fauna de mamíferos englobando todo o gradiente latitudinal e longitudinal da Chapada Diamantina foi realizado até o momento. Seis coletas foram realizadas em 18 localidades diferentes entre Dezembro/2002 e Fevereiro/2004. Os espécimes foram capturados em armadilhas Sherman e pitfall, cariotipados, preparados e foram depositados no Museu Nacional, Rio de Janeiro. Também foram analisados espécimes anteriormente depositados na Coleção de Mamíferos do Museu Nacional. Um total de 19 espécies foram registradas, sendo que destas, 12 são novos registros para a região. Todas as espécies foram caracterizadas morfologicamente no nível craniano e da morfologia externa. As análises cariotípicas foram realizadas em 14 espécies, sendo que o número diplóide e fundamental foram dados para 18 espécies. As 19 espécies registradas podem ser separadas em três principais grupos em relação ao ambiente. O primeiro, mais amplo, encontrado em habitats de caatinga e agreste, o segundo, composto por espécies que frequentam ambientes mais florestados e o terceiro, característico de altitudes extremas como campos rupestres e formações rochosas. Um padrão de diversidade no gradiente latitudinal também foi observado. Cinco das 19 espécies registradas ocorrem somente em altitudes acima de 1000m. Considerando os roedores coletados neste estudo, a Serra do Sincorá (região central) e Morro do Chapéu (região norte) apresentaram a fauna de roedores mais diversa. Somando com as espécies anteriormente depositadas no Museu Nacional, a Serra do Sincorá passa a ser a mais diversa. Três áreas foram consideradas como potenciais para a preservação, sendo elas localizadas nos municípios de Mucugê e Palmeiras, na Serra do Sincorá e a região de Morro do Chapéu. / The Chapada Diamantina is a vast mountainous plateau in the interior of Bahia state, with altitudes varying from 400 to 2000m. No systematic mammal survey encompassing the total latitudinal and altitudinal ranges of the Chapada Diamantina was attempted so far. Six expeditions were performed in to a total of 18 different sampling localities, between December/2002 and February/2004. Specimens were captured in Sherman and pit-fall traps, karyotyped and prepared as vouchers deposited in the Museu Nacional, Rio de Janeiro. In addition, specimens previously deposited in mammal's collection in Museu Nacional were also analyzed. A total of 19 species of rodents was registered and 12 of them are new registers for the area. All species were characterized on the basis of cranial morphology and pelage coloration. Karyological studies were performed to 14 species but the diploid and fundamental numbers were given to 18 species recorded. The 19 species can be separated in three main groups. a more widespread one, proper of caatinga and agreste habitats, a second one, composed mainly by forms from more densely forested landscapes, and the third group, which usually occurs in altitudinal fields in the rocky outcrops of higher limits of the Chapada Diamantina. A pattern of latitudinal diversity was also observed. Five of the 19 species registered occurs only above 1000m. The Serra do Sincorá (central region) and Morro do Chapéu (north region) presented the most diverse rodents fauna, considering the specimens collected in our surveys. In addition with the species previously deposited in Museu Nacional, the Serra do Sincorá region is the most diverse. Therefore, three areas were considered as potentially areas for preservation in Chapada Diamantina: Mucugê and Palmeiras located in Serra do Sincorá and Morro do Chapéu.
54

A Model For The Transcriptional Regulation Of The CYP2B1/B2 Gene In Rat Liver

Prabhu, Leena 11 1900 (has links) (PDF)
No description available.
55

The genetics and embryopathology of exencephaly in SELH/Bc mice

Macdonald, Karen Beth January 1988 (has links)
This project was the first study of the genetics and embryo-pathology of exencephaly in a partially inbred mouse stock, SELH/Bc. Exencephaly was found in 17% of SELH fetuses. Analysis of day 8-9 gestation embryos indicated that SELH embryos were collectively normal in general development, but delayed in neural tube closure relative to overall or general development compared to two normal strains of mice, ICR/Be and SWV/Bc. Exencephaly was observed to be caused by a failure of fusion of the cranial neural folds in the mesencephalon region in SELH. All SELH embryos appeared to be abnormal in their pattern of cranial neural tube closure. They fail to make initial contact at the prosencephalon/mesencephalon junction region of the cranial neural folds (the first fusion in the cranial neural folds in normal embryos). SELH embryos, fused their anterior neural folds via an alternate (possibly passive) mechanism compared to normal strains of mice (SWV/Bc, and ICR/Be), by fusing the folds in a "zipper-like" fashion from the rostral base of the prosencephalon. This closure of the neural tube in genetically liable embryos by an abnormal sequence of events suggests a new model for anterior neural tube closure failure. Liability to exencephaly appeared to be fixed in the SELH stock. Of the 53 SELH males tested, all produced exencephaly. SELH animals were found to be heterogeneous in the frequency of exencephaly they produced, indicating that there are still genes segregating in the stock which affect the ability of embryos to complete anterior neural tube closure. Exencephaly in SELH does not appear to be caused by an autosomal dominant, sex-linked dominant or recessive, or simple autosomal recessive single gene, although F2, BCl, and BC2 exencephaly frequencies (after an outcross to ICR/Be) suggest that only a small number of genes are involved. A marked excess of female exencephalics was observed in SELH, F2, BCl, and BC2 fetuses. / Medicine, Faculty of / Medical Genetics, Department of / Graduate
56

Investigation of some biochemical parameters relating to energy metabolism in experimental rodent tumours after exposure to ionizing radiation and magnetic fields

Loef, David Szeinfeld 18 April 2017 (has links)
No description available.
57

The First Eocene Rodents From the Pacific Northwest, USA

Samuels, Joshua X., Korth, William W. 01 January 2017 (has links)
The Oligocene and Miocene faunas of the John Day Basin are diverse and very well-studied, including a large number of small mammal species. Though Eocene floras from Oregon are well-known, Eocene faunas include relatively few taxa from only two described localities in the Clarno area. The first Eocene rodents from the John Day Basin also include the first ischyromyids from the Pacific Northwest. Several rodent incisors were recovered from the Hancock Mammal Quarry at Clarno, representing the first rodent specimens known from the Clarno Formation. The Hancock Mammal Quarry lies between tuffs dated 42.7 and 39.22 Ma, meaning these rodents are latest Uintan or earliest Duchesnean in age. Several ischyromyids are also described from the Big Basin Member of the John Day Formation. From a Duchesnean locality between tuffs dated 39.22 and 38.4 Ma a single tooth of Pseudotomus was recovered, which is as large as any known ischyromyid. Another Big Basin Member site yielded a new genus and species of ischyromyid. That site lies above an ash dated 36.21 Ma and biostratigraphy confirms a Chadronian age. These rodents help fill important gaps in the fossil record of the John Day Basin and will facilitate comparisons with other Eocene sites in North America and Asia.
58

The Impacts of Cenozoic Climate and Habitat Changes on Small Mammal Diversity of North America

Samuels, Joshua X., Hopkins, Samantha S.B. 01 February 2017 (has links)
Through the Cenozoic, paleoclimate records show general trends of global cooling and increased aridity, and environments in North America shifted from predominantly forests to more open habitats. Paleobotanical records indicate grasses were present on the continent in the Eocene; however, paleosol and phytolith studies indicate that open habitats did not arise until the late Eocene or even later in the Oligocene. Studies of large mammalian herbivores have documented changes in ecomorphology and community structure through time, revealing that shifts in mammalian morphology occurred millions of years after the environmental changes thought to have triggered them. Smaller mammals, like rodents and lagomorphs, should more closely track climate and habitat changes due to their shorter generation times and smaller ranges, but these animals have received much less study. To examine changes in smaller mammals through time, we have assembled and analyzed an ecomorphological database of all North American rodent and lagomorph species. Analyses of these data found that rodent and lagomorph community structure changed dramatically through the Cenozoic, and shifts in diversity and ecology correspond closely with the timing of habitat changes. Cenozoic rodent and lagomorph species diversity is strongly biased by sampling of localities, but sampling-corrected diversity reveals diversity dynamics that, after an initial density-dependent diversification in the Eocene, track habitat changes and the appearance of new ecological adaptations. As habitats became more open and arid through time, rodent and lagomorph crown heights increased while burrowing, jumping, and cursorial adaptations became more prevalent. Through time, open-habitat specialists were added during periods of diversification, while closed-habitat taxa were disproportionately lost in subsequent diversity declines. While shifts among rodents and lagomorphs parallel changes in ungulate communities, they started millions of years earlier than in larger mammals. This is likely a consequence of the smaller mammal' greater sensitivity to environmental changes and more rapid evolution. These results highlight the importance of examining understudied members of vertebrate faunas for understanding the evolution of terrestrial communities through time.
59

Understanding Neural Networks in Awake Rat by Resting-State Functional MRI: A Dissertation

Liang, Zhifeng 01 May 2013 (has links)
Resting-state functional magnetic resonance imaging (rs-fMRI) is a non-invasive neuroimaging technique that utilizes spontaneous low-frequency fluctuations of blood-oxygenation-level dependent (BOLD) signals to examine resting-state functional connectivity in the brain. In the past two decades, this technique has been increasingly utilized to investigate properties of large-scale functional neural networks as well as their alterations in various cognitive and disease states. However, much less is known about large-scale functional neural networks of the rodent brain, particularly in the awake state. Therefore, we attempted to unveil local and global functional connectivity in awake rat through a combination of seed-based analysis, independent component analysis and graph-theory analysis. In the current studies, we revealed elementary local networks and their global organization in the awake rat brain. We further systematically compared the functional neural networks in awake and anesthetized states, revealing that the rat brain was locally reorganized while maintaining global topological properties from awake to anesthetized states. Furthermore, specific neural circuitries of the rat brain were examined using resting-state fMRI. First anticorrelated functional connectivity between infralimbic cortex and amygdala were found to be evident with different preprocessing methods (global signal regression, regression of ventricular and white matter signal and no signal regression). Secondly the thalamocortical connectivity was mapped for individual thalamic groups, revealing group-specific functional cortical connections that were generally consistent with known anatomical connections in rat. In conclusion, large-scale neural networks can be robustly and reliably studied using rs-fMRI in awake rat, and with this technique we established a baseline of local and global neural networks in the awake rat brain as well as their alterations in the anesthetized condition.
60

Production of monoclonal antibodies to sugarcane yellow leaf virus using recombinant read-through protein.

Coates, David, Danks, C., Korimbocus, J., Preston, S., Boonham, N., Barker, I. 21 July 2009 (has links)
No / Yellow leaf syndrome (YLS) of sugarcane is associated with sugarcane yellow leaf virus (SCYLV), a member of the family Luteoviridae. A fragment of the coat protein and readthrough domain of SCYLV was expressed in a bacterial expression system. The resulting protein was purified and used to immunize mice for monoclonal antibody (MAb) production. Two MAbs, 3A2E3 and 2F7H5, were selected following the screening of hybridoma cells using both plate-trapped antigen enzyme-linked immunosorbent assay (PTA-ELISA) and tissue blot immunoassay (TBIA). These MAbs can be incorporated into the TBIA assay currently used for the routine detection of SCYLV but could not be used in triple antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA). The two antibodies selected have slightly different specificities. Antibody 3A2E3 gave equivalent results to a polyclonal antiserum (raised to purified virus) in comparative testing using TBIA. The MAbs produced should provide a widely available, uniform reagent for SCYLV diagnosis with the potential to help manage YLS.

Page generated in 0.065 seconds