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  • 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.
41

Pheromonal mediation of reproductive behavior in the brown tree snake

Greene, Michael John 18 June 1998 (has links)
In animals, reproductive behaviors serve to attract individuals together during the breeding season and to coordinate the behavioral and physiological states of individuals so that mating can successfully occur. In snakes, the various reproductive behaviors including courtship, mating, courtship inhibition, male combat and trailing are mediated primarily by pheromones. Pheromones are naturally produced chemical signals that influence the physiology or behavior of a conspecific when released by one individual into the environment. The research included in this study was designed to characterize the role pheromones play in the mediation of reproductive behaviors of the brown tree snake (Boiga irregularis) a rear-fanged, arboreal colubrid native to Australia, Papua-New Guinea and the Solomon Islands. Much attention has been paid to this species as it is an introduced pest species on the Pacific island of Guam where it has caused considerable economic and ecological damage. In order to create behavioral bioassays designed to experimentally determine the role pheromones play in the mediation of brown tree snake reproductive behavior, the complete repertoire of courtship, mating and male combat behaviors were described. Male brown tree snakes display combat and courtship behaviors similar to other colubrid species while female brown tree snakes take a very active role in courtship, displaying behaviors that both release and inhibit male courtship. These data represent the first description of any reproductive behaviors in this species and one of only a few studies examining the reproductive behaviors of a tropical species. A behavioral bioassay measuring the release of male courtship behavior was utilized to isolate and characterize the female sex pheromone of this species as a suite of non-polar, non-volatile skin lipid molecules. Using another bioassay, the pheromonal inhibition of male courtship behavior by a volatile pheromone originating from female cloacal secretions was characterized. Lastly, pheromone mediated mate attraction was examined by determining the abilities of male brown tree snakes to follow conspecific pheromone trails during the breeding season. Male brown tree snakes possess the ability to follow both male and female pheromone trails but did not, however, discriminate between male and female pheromones trails when given a choice. / Graduation date: 1999
42

Geomagnetic sensitivity and orientation in eastern garter snakes (Thamnophis sirtalis) /

Smith, Douglas Eliot. January 2002 (has links)
Thesis (Ph. D.)--University of Rhode Island, 2002. / Typescript. Includes bibliographical references (leaves 96-102).
43

Chemosensory and behavioral ecology of the dipsadid snakes Contia tenuis, Diadophis punctatus, and Hypsiglena chlorophaea /

Weaver, Robert Elbert. January 2010 (has links) (PDF)
Thesis (Ph. D.)--Washington State University, May 2010. / Title from PDF title page (viewed on June 7, 2010). "School of Biological Sciences." Includes bibliographical references.
44

The expedition of Peter Skene Ogden in the Snake River region with a brief survey of previous travel and exploration in that region /

Francis, Jessie Davies. January 1925 (has links)
Thesis (M.A. in History)--University of California, Berkeley, Aug. 1925. / Includes bibliographical references (leaves i-viii).
45

Ação de compostos vegetais sobra a atividade da Piratoxina-I, isolada do veneno de Bothrops pirajai, em preparação neuromuscular de camundongos

Cardoso, Fábio Florença [UNESP] 15 July 2011 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:25:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-07-15Bitstream added on 2014-06-13T18:26:28Z : No. of bitstreams: 1 cardoso_ff_me_botib.pdf: 693511 bytes, checksum: ce598a499b044fd23ed66dd6f42f2f0a (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os acidentes envolvendo as serpentes do gênero Bothrops se destacam no Brasil e em outros países da América Latina, representando 90% das notificações. O envenenamento botrópico é caracterizado por intensa mionecrose local que não é eficientemente neutralizada pelo único tratamento disponível, isto é, a soroterapia. Como conseqüência, em casos graves, este acidente pode levar a amputação de membros, desabilitando a vítima. Os principais responsáveis pelo desenvolvimento da mionecrose são proteínas com estruturas homólogas às enzimas fosfolipases A2 (PLA2s). Entre essas se destacam as variantes cataliticamente inativas que apresentam como característica um resíduo de lisina na posição 49 (Lys49-PLA2s). Tradicionalmente, as Lys49-PLA2s são consideradas miotoxinas não-neurotóxicas, uma vez que não induzem paralisia in vivo. No entanto, em preparações isoladas, tal efeito é observado. Recentemente, sugeriu-se que a paralisia muscular in vitro, da mesma forma que a lesão muscular, resultaria da atividade desestabilizadora de membrana da fibra muscular induzida por estas toxinas. O presente estudo teve como objetivo investigar a relação entre os efeitos miotóxico e paralisante das Lys49-PLA2s e contribuir para o esclarecimento do mecanismo de ação e da relação estrutura/atividade dessas toxinas. Sendo assim, realizaram-se estudos miográficos e morfológicos em preparações neuromusculares de camundongos utilizando a PrTX-I (Lys49-PLA2 isolada do veneno de Bothrops pirajai) e potenciais inibidores vegetais (ácido rosmarínico, ácido caféico e ácido aristolóquico). Os resultados obtidos mostraram as diferentes capacidades dos compostos vegetais em neutralizar os efeitos miotóxico e paralisante da PrTX-I. Assim, o ácido rosmarínico neutralizou ambos os efeitos eficientemente... / Accidents caused by Bothrops snake genus stand out in Brazil and other Latin American countries, representing 90% of notifications. Bothropic envenoming is characterized by intense local myonecrosis, not effectively neutralized by serum therapy, the only available treatment. As a result, in severe cases, these accidents can lead to amputation of limbs, disabling the victim. The main responsibles for myonecrosis development are proteins with homologous structures from enzymes phospholipase A2 (PLA2s). Among these stand out catalytically inactive variants that have a characteristic lysine residue at position 49 (Lys49-PLA2s). Traditionally, Lys49-PLA2s myotoxins are considered non-neurotoxic, since they do not induce paralysis in vivo. However, this effect is observed in isolated preparations. It was recently suggested that muscle paralysis in vitro, as well as muscle injury, would result from the destabilizing activity of the muscle fiber membrane induced by these toxins. This study aimed to investigate the relationship between paralyzing and myotoxic effects of Lys49-PLA2s and contribute to the elucidation of the mechanism of action and structure/activity relationship of these toxins. Therefore, myographical and morphological studies were performed in neuromuscular preparations of mice using PrTX-I (Lys49-PLA2 isolated from Bothrops pirajai venom) and potential inhibitors from plants (rosmarinic acid, caffeic acid and aristolochic acid) as experimental tools. The results showed the different skills of plant compounds to neutralize myotoxic and paralyzing effects of PrTX-I. Thus, the rosmarinic acid efficiently neutralized both effects, whereas caffeic acid only partially inhibited the... (Complete abstract click electronic access below)
46

Epidemiologia dos acidentes ofídicos, Estado do Ceará, Brasil (2007-2013) / Epidemiology of official accidents, State of Ceará, Brazil (2007-2013)

BELMINO, José Franscidavid Barbosa. 25 July 2018 (has links)
Submitted by Rosana Amâncio (rosana.amancio@ufcg.edu.br) on 2018-07-25T20:37:15Z No. of bitstreams: 1 JOSÉ FRANSCISDAVID BARBOSA BELMINO- DISSERTAÇÃO PPGCNBio 2015..pdf: 2603348 bytes, checksum: 2fbb701d116d617718c670099be997a9 (MD5) / Made available in DSpace on 2018-07-25T20:37:15Z (GMT). No. of bitstreams: 1 JOSÉ FRANSCISDAVID BARBOSA BELMINO- DISSERTAÇÃO PPGCNBio 2015..pdf: 2603348 bytes, checksum: 2fbb701d116d617718c670099be997a9 (MD5) Previous issue date: 2015-08-28 / CNPq / Os casos de acidentes ofídicos são um problema de saúde pública para países de regiões tropicais. O presente estudo é uma investigação retrospectiva que descreve e analisa as características epidemiológicas dos casos de acidentes ofídicos no Estado do Ceará, Brasil, de 2007 a 2013. Os dados foram coletados na Secretaria Estadual de Saúde do Ceará, utilizando a base de dados do Sistema de Informação de Agravos de Notificação. Foram analisados um total de 4 058 casos. Os acidentes foram distribuídos em todos os meses dos anos, ocorrendo com maior frequência entre os meses de março (n = 437) a julho (n = 479). A maioria dos casos afetou homens (n = 3 275), na faixa etária entre 20 e 29 anos (n = 696), com baixo nível de escolaridade (n = 1 821), pardos (n = 2 729), residentes (n = 3 327) e trabalhadores (n = 1 360) rurais. Os casos ocorreram predominantemente na zona rural (n = 3 623) e sem relação com o trabalho (n = 1 984). O gênero Bothrops foi responsável pelo maior número de casos (n = 3 319). O pé foi região do corpo mais atingida pelas picadas (n = 2 027). A maioria das vítimas foi atendida entre 1 e 3 horas após o acidente (n = 1 718). Ocorreram mais manifestações locais (n = 3 468) que sistêmicas (n = 785). O sintoma local mais frequente foi dor (n = 3 211) e o sistêmico foram as manifestações hemorrágicas (n = 262). A maior parte dos acidentes foram classificados como leve (n = 2 463) e evoluíram para cura (n = 3 564). A soroterapia foi administrada na maioria dos casos (n = 3 534). Os acidentes ofídicos no Estado do Ceará pode ser considerado um problema de saúde pública. Treinamento adicional para os profissionais de saúde parecem ser necessários para aprimorar a sua capacidade para coletar os dados epidemiológicos, bem para melhorar o atendimento as vítimas dos acidentes ofídicos. / The cases of snakebites are a public health issue for countries from tropical regions. This study is a retrospective research to describe and analyze the epidemiological characteristics of cases of snakebites in the State of Ceará, Brazil, from 2007 to 2013. Data was collected from the Injury Notification Information System database of the Health Department of Ceará. A total of 4,058 cases were analyzed. Snakebites were distributed in every month of the year, occurring most between the months from March (n = 437) to July (n = 479). Most cases affected young men (n = 3,275), aged between 20 and 29 years old (n = 696), with low educational level (n = 1,821), brown skin (n = 2,729), rural residents (n = 3,327) and workers (n = 1,360). The cases occurred predominantly in rural areas (n = 3,623) and unrelated to the work (n = 1 984). The genus Bothrops was responsible for the largest number of cases (n = 3,319). The part of the body most affected by the bites was the foot (n = 2,027). Most of the victims was attended between 1 and 3 hours after the accident (n = 1,718). There were more local events (n = 3,468) that systemic (n = 785). The most frequent site symptom was pain (n = 3,211) and systemic were hemorrhagic manifestations (n = 262). Most cases were classified as mild (n = 2,463) and were cured (n = 3,564). The antivenom was administered in most cases (n = 3,534). The snakebites in the State of Ceará may be considered an environmental health problem. Additional training for health professionals appear to be necessary to enhance their ability to collect epidemiological data and to improve the care of victims of snakebites.
47

A comparative osteological study of two species of Colubridae (Pituophis and Thamnophis)

Bullock, Robert E. 01 May 1964 (has links)
With reference to anatomical studies it appears that the aerpents are indeed a neglected group ot reptiles. Although some early writers recorded a few fragmentary obser-vations on the anatomy of snakes, no attempt was made to undertake a complete comprehensive study. Cole (1944) has rightfully referred to this section of vertebrate anatomy as "almost virgin field." The serpent area of reptilian anatomy is deserving ot a more intensive investigation because of the considerable number ot adaptations demonatrated by this group of reptiles in relation to their peculiar types ot locomotion and methods ot feeding. It is important to understand the anatomical specializations of this group of animals if we are to understand more completely the evolutionary trends among the vertebrates. It is also quite evident that compara-tive descriptions of certain serpents, which have been based mainly on external characteristics, need to be supplemented by accounts of their internal anatomy.
48

Scolecophidia (Serpentes) of the Late Oligocene and Early Miocene, North America, and a Fossil History Overview

Mead, Jim I. 01 January 2013 (has links)
An abundant fossil record of the snake clade Scolecophidia exists in Europe; however, the minute snake is noticeably absent in reports about the North American Paleogene and Neogene. Presented here are four localities from Florida, USA, that contain scolecophidian remains older than the Pleistocene: Thomas Farm (late Early Miocene, Hemingfordian Land Mammal Age, LMA), Live Oak (Oligocene-Miocene transition, latest Arikareean LMA), White Springs 3B (late Arikareean LMA), and Brooksville 2 (Late Oligocene, middle Arikareean LMA). These remains extend their known existence by about 26. m.y. and are now the oldest reported scolecophidian remains in North America. Molecular evidence on extant scolecophidians concludes that these tiny snakes have a Gondwanan origin. Interestingly, the oldest record of a scolecophidian is from Europe (Belgium) and dates back to the middle Paleocene (MP 1-5). The earliest African record of the snake clade comes from the Paleocene-Eocene boundary in Morocco. The clade is apparently absent from Europe and Middle East deposits dating from the latest Eocene through to the latest Oligocene (MP 19-30) and to the Early Miocene (MN 4). A portion of this time is known as the booid 'Dark Period' which represents an apparent response to global aridization and cooling. Scolecophidians appear to re-emerge into the southern Eurasian record in the Early Miocene (MN 4) and become widely dispersed throughout Europe and Middle East. The fossil record of these minute snakes is largely absent in southern Asia and South America. It is possible that the current lack of a decent fossil scolecophidian record outside of Europe and Middle East is due mainly to a bias in the methodology to recover fossils; wet sieving sediments through. < 1.0. mm mesh is needed to recover the minuscule vertebrae.
49

Scolecophidia (Serpentes) of the Late Oligocene and Early Miocene, North America, and a Fossil History Overview

Mead, Jim I. 01 January 2013 (has links)
An abundant fossil record of the snake clade Scolecophidia exists in Europe; however, the minute snake is noticeably absent in reports about the North American Paleogene and Neogene. Presented here are four localities from Florida, USA, that contain scolecophidian remains older than the Pleistocene: Thomas Farm (late Early Miocene, Hemingfordian Land Mammal Age, LMA), Live Oak (Oligocene-Miocene transition, latest Arikareean LMA), White Springs 3B (late Arikareean LMA), and Brooksville 2 (Late Oligocene, middle Arikareean LMA). These remains extend their known existence by about 26. m.y. and are now the oldest reported scolecophidian remains in North America. Molecular evidence on extant scolecophidians concludes that these tiny snakes have a Gondwanan origin. Interestingly, the oldest record of a scolecophidian is from Europe (Belgium) and dates back to the middle Paleocene (MP 1-5). The earliest African record of the snake clade comes from the Paleocene-Eocene boundary in Morocco. The clade is apparently absent from Europe and Middle East deposits dating from the latest Eocene through to the latest Oligocene (MP 19-30) and to the Early Miocene (MN 4). A portion of this time is known as the booid 'Dark Period' which represents an apparent response to global aridization and cooling. Scolecophidians appear to re-emerge into the southern Eurasian record in the Early Miocene (MN 4) and become widely dispersed throughout Europe and Middle East. The fossil record of these minute snakes is largely absent in southern Asia and South America. It is possible that the current lack of a decent fossil scolecophidian record outside of Europe and Middle East is due mainly to a bias in the methodology to recover fossils; wet sieving sediments through. < 1.0. mm mesh is needed to recover the minuscule vertebrae.
50

Early Pleistocene Snake (Squamata, Reptilia) Skeleton From Renzidong Cave, Anhui, China

Mead, Jim I., Moscato, David, Schubert, Blaine W., Jin, Changzhu, Wei, Guangbiao, Sun, Chengkai, Zheng, Longting 01 January 2016 (has links)
The Quaternary record of fossil snakes (Reptilia, Squamata) in Asia is extremely rare; any information is noteworthy. An articulated snake skeleton was recovered from the early Pleistocene (2.15–2.14 Ma) deposits in Renzidong Cave, Yangtze River Valley, east-central China. The skeleton contains about 122 nearly complete vertebrae but lacks the cranium and caudal vertebrae. Preserved vertebral characters indicate that the snake is particularly similar to the rat snake, Elaphe (Colubridae) especially with the European Elaphe praelongissima (late Miocene). We identify the specimen as cf. Elaphe sp. This genus and ‘Coluber s.l.’ are unfortunately similar and difficult to differentiate based on just vertebral comparisons of species living in Europe. Adequate comparative skeletons of living snakes of eastern Asia are noticeably absent in museums making identifications of fossil specimens less than satisfactory. Finding dated fossil remains of the snake Elaphe in Asia holds importance to the understanding of its time of dispersal between Asia, Europe and North America, but this can only be adequately examined with fossil remains accurately and satisfactorily identified.

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