• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 9
  • 7
  • 3
  • 1
  • 1
  • 1
  • Tagged with
  • 25
  • 25
  • 8
  • 6
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 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.
1

Role of gonadal steroids in the mating behaviour of the ram Ovis aries L. /

D'Occhio, Michael J. January 1983 (has links) (PDF)
Thesis (Ph.D.)-- University of Adelaide, Dept. of Animal Sciences,1983. / Typescript (photocopy). Includes bibliographical references (leaves 198-259).
2

Origin and maintenance of genetic diversity in northern European sheep

Tapio, M. (Miika) 01 November 2006 (has links)
Abstract The Nordic and Baltic countries and North-western Russia have >20 old native sheep breeds. These together with recently synthesized breeds and local populations of international breeds make up the northern European sheep diversity. Changes in agriculture threaten to erode genetic diversity in sheep. Molecular genetic variation was assessed to understand genetic diversity in northern European sheep. Distribution of maternal lineages were studied based on mitochondrial control region variation in 76 sheep breeds in northern Europe and in a wide neighbouring area extending to the Caucasus and Central-Asia. Autosomal microsatellite variation was studied in 37 northern European breeds, and autosomal blood protein variation was studied in six Finnish and Russian breeds. Four distinct maternal lineages were observed in Eurasian sheep. Their distribution agrees with sheep expansion starting from the Near East. Two most common distinct lineages were recorded in northern Europe. Majority of northern sheep have the lineage, which predominates in other parts of Europe. Results suggest that the main maternal origin of northern sheep is in the south. However, rare "Asian" lineage was observed in several old northern European breeds. The rare type in the Nordic sheep is descendant to the type observed in the Middle Volga region, which suggest that some sheep were brought to northern Europe from the east. Microsatellites showed clustering of geographically neighbouring sheep, when breed locations are corrected for the recent transportations. The analysis separated long and short-tailed sheep, although this macroscale structure explains a small proportion of breed differences. Differentiation among the northern European breeds is stronger than typically observed in sheep. Many native breeds are less inbred than the local populations of the international breeds, but some rare breeds and subpopulations of divided unofficial strains were inbred. Some breeds require more careful maintenance due to recent population size reduction. Maintaining prolificacy in breeds such as the Finnsheep and the Romanov may require efficient avoidance of inbreeding. The breeds were ranked for conservation using simultaneously within-breed variation and breed divergence. Set of important breeds included seven rare old native breeds or strains which merit efficient conservation measures urgently.
3

Role of gonadal steroids in the mating behaviour of the ram Ovis aries L.

D'Occhio, Michael J. January 1982 (has links) (PDF)
Typescript (photocopy) Includes bibliographical references (leaves 198-259) The role of gonadal steroids in the mating behaviour of rams was investigated in both entire rams and castrated rams (wethers) treated with different steroids.
4

Role of gonadal steroids in the mating behaviour of the ram Ovis aries L. / by Michael J. D'Occhio

D'Occhio, Michael J. January 1983 (has links)
Typescript (photocopy) / Includes bibliographical references (leaves 198-259) / xvi, 259 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The role of gonadal steroids in the mating behaviour of rams was investigated in both entire rams and castrated rams (wethers) treated with different steroids. / Thesis (Ph.D.)--University of Adelaide, Dept. of Animal Sciences,1983
5

Role of gonadal steroids in the mating behaviour of the ram Ovis aries L. / by Michael J. D'Occhio

D'Occhio, Michael J. January 1983 (has links)
Typescript (photocopy) / Includes bibliographical references (leaves 198-259) / xvi, 259 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The role of gonadal steroids in the mating behaviour of rams was investigated in both entire rams and castrated rams (wethers) treated with different steroids. / Thesis (Ph.D.)--University of Adelaide, Dept. of Animal Sciences,1983
6

Bleats from the north : Evaluation of osteological methods with support of archaeogenetics to distinguish between sheep and goats / Bräkanden från Norden : Utvärdering av osteologisk metod med stöd av arkeogenetik för att särskiljamellan får och getter

Theorell, Hannes January 2014 (has links)
This study is an extension of the author's previous thesis (Theorell 2013) and focus on the analysed tibia, the humerus and the proximal and distal part of the radius of sheep bones from Gotland and goat bones from City of Falun. Methods for bone elements assessed in this study are compiled and evaluated by Zeder and Lapham (2010). The bones were then geneticallyspecies identified and the results were compared. Seven of thirteen criteria for both sheep and goat reached 100% of correct identification.Best performing criteria were on humerus and distal radius for both sheep and goats. The results for the complete bone assessments divided for the species showed best performance ongoats. Worst performing bone is the tibia. High performing criteria were found on all thetypes of bones used in this study which can be used to distinguish between sheep and goats. / Föreliggande studie är en utökning av författarens tidigare magisteruppsats (Theorell 2013) och fokuserar på att analysera skenben, överarmsben samt proximal och distal del av strålbenet från fårben från Gotland och getben från Falun. Metoder för benslagen som används i denna studie har samlats och utvärderats av Zeder och Lapham (2010). Efter osteologisk analys har benen genetiskt artidentifierats och resultaten från bägge analyser har jämförts. Sju av tretton kriterier för både får och getter visade 100% korrekt bedömning. Kriterier med bäst resultat fanns på överarmsben och distalt på strålben. Sett till bedömning av komplett benslag skilt mellan får och getter visade att metoderna presterade bäst på getter. Sämst resultat uppvisades på skenbenet. Generellt uppvisade samtliga benslag kriterier som är möjliga att använda för att särskilja mellan får och getter.
7

AnÃlise genÃmica das principais raÃas de ovinos brasileiras / Genomic analysis of the major brazilian sheep breeds

JoÃo Josà de Simoni Gouveia 29 April 2013 (has links)
nÃo hà / As raÃas de ovinos localmente adaptadas brasileiras, tambÃm conhecidas como nativas ou crioulas, descendem de animais trazidos durante o perÃodo colonial e, desde aquela Ãpoca, vÃm sendo submetidas a processos evolutivos sistemÃticos e nÃo sistemÃticos., o que resultou na formaÃÃo de genÃtipos altamente adaptados Ãs mais diversas condiÃÃes ambientais brasileiras. Embora estas raÃas nÃo possuam o mesmo potencial produtivo das raÃas exÃticas melhoradas, elas sÃo consideradas extremamente importantes devido Ãs relaÃÃes sociais e culturais que guardam com as populaÃÃes do campo. AlÃm disso, as raÃas localmente adaptadas possuem caracterÃsticas adaptativas importantÃssimas para a manutenÃÃo de sistemas produtivos tradicionais. A otimizaÃÃo da utilizaÃÃo dos recursos genÃticos naturalizados depende de um conhecimento profundo destas populaÃÃes e, portanto, a caracterizaÃÃo morfolÃgica, produtiva e molecular sÃo ferramentas imprescindÃveis para o sucesso da conservaÃÃo e utilizaÃÃo deste recurso genÃtico. Com base nisso, o objetivo desta tese foi aprofundar os estudos de caracterizaÃÃo molecular das principais raÃas de ovinos localmente adaptadas brasileiras: Crioula Lanada, Morada Nova e Santa InÃs. Assim, o capÃtulo I intitulado âIdentificaÃÃo de assinaturas de seleÃÃo em animais de produÃÃoâ consiste em uma revisÃo cujo objetivo à descrever os principais efeitos da seleÃÃo natural/artificial nos genomas das espÃcies de animais de produÃÃo, apresentar os principais mÃtodos de anÃlise de assinaturas de seleÃÃo e discutir os recentes avanÃos nesta Ãrea de estudo. Foram realizados dois estudos que resultaram nos capÃtulos II e III desta tese. O capÃtulo II, intitulado âIdentificaÃÃo de assinaturas de seleÃÃo em ovinos de raÃas localmente adaptadas brasileirasâ, teve como objetivo a identificaÃÃo e caracterizaÃÃo de regiÃes genÃmicas provÃveis de estar sob seleÃÃo nas trÃs principais raÃas brasileiras localmente adaptadas de ovinos e caracterizar estar regiÃes com a finalidade de identificar genes envolvidos com diferenÃas produtivas/adaptativas entre estas raÃas. A identificaÃÃo das regiÃes sujeitas à seleÃÃo foi feita com base em dois tipos de metodologia: diferenciaÃÃo entre populaÃÃes (FST) e desequilÃbrio de ligaÃÃo (iHS e Rsb). Foram identificados 78 genes candidatos envolvidos com funÃÃes como: resposta imune, desenvolvimento do sistema nervoso, percepÃÃo sensorial e desenvolvimento de pelos/lÃ. O capÃtulo III, intitulado: âIdentificaÃÃo de subestrutura de populaÃÃes em ovinos de raÃas localmente adaptadas brasileirasâ, teve como objetivos identificar e caracterizar a presenÃa de subestruturaÃÃo genÃtica dentro das trÃs principais raÃas brasileiras localmente adaptadas de ovinos. Foi observada, de uma forma geral, a presenÃa de diferenciaÃÃo genÃtica bastante considerÃvel ao comparar os rebanhos de cada raÃa analisada. AlÃm disso, tanto na raÃa Crioula Lanada quanto na raÃa Santa InÃs, pode ser observada a presenÃa de grupos bem distintos de indivÃduos, sugerindo a efetiva presenÃa de diferentes ecÃtipos/linhagens dentro destas raÃas. / The Brazilian locally adapted sheep breeds, also known as native and creole, are descendant from animals brought during the settlement period and, since then, are been subjected to evolutive (both systematic and non systematic) processes, what resulted in the formation of highly adapted genotypes to the diverse environmental Brazilian conditions. Although these breeds donât posses the same productive potential when compared with the exotic improved breeds, they are considered extremely important from a social and cultural point of view. Moreover, the locally adapted breeds are essential for the maintenance of traditional production systems. The optimization of the utilization of naturalized genetic resources depends on a deep knowledge of these populations, and then, the morphological, productive and molecular characterizations are essential to the success of conservation and utilization of these locally adapted genotypes. Therefore, the principal aim of this thesis was to deepen molecular the knowledge of the three main locally adapted Brazilian sheep breeds: Brazilian Creole, Morada Nova and Santa Ines. Thus, Chapter I entitled "Identification of selection signatures in livestock species" is a literature review that is proposed to describe the main effects of natural/artificial selection in the genomes of species of farm animals, present the main methods of signature selection analysis and discuss recent advances in this area of study. Two studies were conducted and resulted in the chapters II and III of this thesis. The chapter II, entitled âIdentification of selection signatures in brazilian locally adapted sheep breedsâ, aimed the identification and characterization of putative genomic regions that underwent selection and the identification of candidate genes related to productive/adaptative differences between these breeds. The identification of signatures of selection was performed through two approaches: population differentiation (FST) and linkage disequilibrium (iHS and Rsb). Seventy eight genes, related to functions as: immune response, nervous system development, sensorial perception and wool/hair development were identified. The chapter III, entitled âIdentification of population substructure in brazilian locally adapted sheep breedsâ, aimed the identification and characterization of of genetic substructure within the three main locally adapted Brazilian sheep breeds: Brazilian Creole, Morada Nova and Santa Ines. The level of genetic differentiation between herds of the same breeds was, in general, high. Both in the Brazilian Creole and in the Santa Ines breeds the presence of distinct groups on animals could be observed, what suggests the occurrence of different ecotypes/lineages within these breeds.
8

Déplacements collectifs auto-organisés : décision individuelle et transfert d'information / Self-organized collective movements : individual decision and information transfer

Toulet, Sylvain 13 November 2015 (has links)
Les déplacements collectifs se manifestent souvent de façon spectaculaire et intriguent tant les amateurs de la nature que les chercheurs. Comment émergent ces formes spectaculaires et comment la cohésion des groupes est elle assurée ? Si de nombreux travaux ont été consacrés à l'identification des règles permettant la cohésion dans les groupes en mouvement, plus rares sont ceux consacrés aux transitions entre les états d'arrêt et de déplacement. Cette thèse traite des mécanismes comportementaux impliqués dans les prises de décisions collectives et la dynamique de transition de tels évènements chez le mouton Merinos (Ovis aries). Nous proposons de nouvelles hypothèses sur la modulation des interactions entre individus par des effets spatiaux dans des groupes de grande taille. Nous proposons un modèle spatio-temporel reproduisant nos résultats expérimentaux sur les départs, les déplacements collectifs et les arrêts de groupes de taille croissante et permettant d'explorer les décisions collectives dans des conditions nouvelles. Les résultats expérimentaux et théoriques per- mettent d'améliorer la compréhension des mécanismes individuels à l'origine des décision collectives permettant de maintenir ou non la cohésion des groupes. / Collective movements often involve very spectacular displays that fascinate nature lovers and researchers. How do such amazing patterns appear and how group cohesion can be maintained ? If many studies were carried out to decipher the rules underlying cohesion for groups in movement, there is a lack of works adressing the transitions involved in collective movements : departures and stops. This thesis adresses the behavioural mechanisms involved in the collective decision-making processes oc- curing in such transitions in Merino sheep (Ovis aries) groups. We propose some new kinds of spatial hypotheses that can account for the way interactions between individuals are locally modulated in large groups where individuals cannot have an access to the global information of all individuals. We developed a novel spatiotemporal model of sheep collective motion that reproduces the experimental observations and allows to explore the outcomes of collective decisions in various conditions. The experimental and theoretical results increase the understanding of the individual mechanisms that produce collective decisions allowing to maintain group cohesion.
9

Proliferação celular de estruturas ovarianas de ovelhas pela técnica de coloração AgNOR / Proliferation of ovarian cell structures of ewes by the technique of AgNOR staining

Arrebola, Thaís Andressa Hernandes 24 October 2011 (has links)
Made available in DSpace on 2016-01-26T18:55:33Z (GMT). No. of bitstreams: 1 thais.pdf: 774762 bytes, checksum: aab7c8f9a2cbb52b94d59cd3cc962c07 (MD5) Previous issue date: 2011-10-24 / The sheep industry now occupies an important place of interest within the livestock farms, requiring the development of studies in the area related to sheep breeding on tropical climate. Most of the wool breed have reproductive seasonality, in other words, cycles are controlled by the fading light of the season, on the other hand crossbred sheep usually have already observed reproductive activity throughout the year. The ovarian cortex has follicles and corpus luteumin various stages of development, supported by connective tissue and smooth muscle fibers through the vessels and nerves. Te ovarian marrow is made up of fibroelastic tissue, nerves and arteries, being the innermost part of the ovary. In antral follicles, IGF stimulates the proliferation activity and differentiation of granulosa cells and steroidogenesis. The nucleolar organizer regions (NORs) are loops of deoxyribonucleic acid (DNA) responsible for synthesizing ribosomal ribonucleic acid (rRNA) during interphase, the period of protein synthesis and increase in volume, size and number of cell organelles. Its in the nucleolus, located in the cell nucleus, which has storage and production of rRNA, which will be linked to various proteins to form ribossomes. The AgNOR technique evaluates the NORs of active chromossomes during the cell cycle and the number or area of NORs show that proliferative activity, from the G1 phase of intense production of proteins and RNA, to the maximum in S phase, that have synthesis of DNA, of the cycle. / A ovinocultura atualmente ocupa um lugar de importância dentro dos criatórios de interesse zootécnico, sendo necessário o desenvolvimento de estudos na área de reprodução, relativos aos ovinos criados em clima tropical. Raças lanadas, em sua maioria possuem estacionalidade reprodutiva, ou seja, os ciclos são controlados pela diminuição da luminosidade da estação, já ovelhas mestiças geralmente possuem atividade reprodutiva geralmente observada durante todo o ano. A córtex ovariana possui os folículos e corpos lúteos em vários estádios de desenvolvimento, sustentada por tecido conjuntivo e fibras musculares lisas em meio a vasos e nervos. A medula ovariana é formada de tecido conjuntivo fibroelástico, nervos e artérias, compreendendo a parte mais interna do ovário. Em folículos antrais, o IGF estimula a proliferação, atividade e diferenciação das células da granulosa e a esteroidogênese. As regiões organizadoras de nucléolos (NORs) são alças de ácido desoxirribonucléico (DNA) responsáveis por sintetizar ácido ribonucléico ribossomal (RNAr) durante a intérfase, período de síntese protéica e de aumento de volume, tamanho e número de organelas da célula. É no nucléolo, localizado no núcleo celular, que há armazenamento e produção de RNAr, que ligados à várias proteínas irão formar os ribossomos. A técnica AgNOR avalia as NORs de cromossomos ativos durante o ciclo celular e o número ou área das NORs mostram essa atividade proliferativa, a partir da fase G1, de intensa produção de proteínas e RNA, até o máximo na fase S, de síntese do DNA, do ciclo.
10

Proliferação celular de estruturas ovarianas de ovelhas pela técnica de coloração AgNOR / Proliferation of ovarian cell structures of ewes by the technique of AgNOR staining

Arrebola, Thaís Andressa Hernandes 24 October 2011 (has links)
Made available in DSpace on 2016-07-18T17:53:09Z (GMT). No. of bitstreams: 1 thais.pdf: 774762 bytes, checksum: aab7c8f9a2cbb52b94d59cd3cc962c07 (MD5) Previous issue date: 2011-10-24 / The sheep industry now occupies an important place of interest within the livestock farms, requiring the development of studies in the area related to sheep breeding on tropical climate. Most of the wool breed have reproductive seasonality, in other words, cycles are controlled by the fading light of the season, on the other hand crossbred sheep usually have already observed reproductive activity throughout the year. The ovarian cortex has follicles and corpus luteumin various stages of development, supported by connective tissue and smooth muscle fibers through the vessels and nerves. Te ovarian marrow is made up of fibroelastic tissue, nerves and arteries, being the innermost part of the ovary. In antral follicles, IGF stimulates the proliferation activity and differentiation of granulosa cells and steroidogenesis. The nucleolar organizer regions (NORs) are loops of deoxyribonucleic acid (DNA) responsible for synthesizing ribosomal ribonucleic acid (rRNA) during interphase, the period of protein synthesis and increase in volume, size and number of cell organelles. Its in the nucleolus, located in the cell nucleus, which has storage and production of rRNA, which will be linked to various proteins to form ribossomes. The AgNOR technique evaluates the NORs of active chromossomes during the cell cycle and the number or area of NORs show that proliferative activity, from the G1 phase of intense production of proteins and RNA, to the maximum in S phase, that have synthesis of DNA, of the cycle. / A ovinocultura atualmente ocupa um lugar de importância dentro dos criatórios de interesse zootécnico, sendo necessário o desenvolvimento de estudos na área de reprodução, relativos aos ovinos criados em clima tropical. Raças lanadas, em sua maioria possuem estacionalidade reprodutiva, ou seja, os ciclos são controlados pela diminuição da luminosidade da estação, já ovelhas mestiças geralmente possuem atividade reprodutiva geralmente observada durante todo o ano. A córtex ovariana possui os folículos e corpos lúteos em vários estádios de desenvolvimento, sustentada por tecido conjuntivo e fibras musculares lisas em meio a vasos e nervos. A medula ovariana é formada de tecido conjuntivo fibroelástico, nervos e artérias, compreendendo a parte mais interna do ovário. Em folículos antrais, o IGF estimula a proliferação, atividade e diferenciação das células da granulosa e a esteroidogênese. As regiões organizadoras de nucléolos (NORs) são alças de ácido desoxirribonucléico (DNA) responsáveis por sintetizar ácido ribonucléico ribossomal (RNAr) durante a intérfase, período de síntese protéica e de aumento de volume, tamanho e número de organelas da célula. É no nucléolo, localizado no núcleo celular, que há armazenamento e produção de RNAr, que ligados à várias proteínas irão formar os ribossomos. A técnica AgNOR avalia as NORs de cromossomos ativos durante o ciclo celular e o número ou área das NORs mostram essa atividade proliferativa, a partir da fase G1, de intensa produção de proteínas e RNA, até o máximo na fase S, de síntese do DNA, do ciclo.

Page generated in 0.0679 seconds