1,721,106 research outputs found
Caecilian viviparity and amniote origins: a reply to Wilkinson and Nussbaum
No full textLaurin, Michel, Reisz, Robert R., Girondot, Marc (2000): Caecilian viviparity and amniote origins: a reply to Wilkinson and Nussbaum. Journal of Natural History 34 (2): 311-315, DOI: 10.1080/002229300299651, URL: http://www.tandfonline.com/doi/abs/10.1080/00222930029965
Caecilian viviparity and amniote origins: a reply to Wilkinson and Nussbaum
No full textLaurin, Michel, Reisz, Robert R., Girondot, Marc (2000): Caecilian viviparity and amniote origins: a reply to Wilkinson and Nussbaum. Journal of Natural History 34 (2): 311-315, DOI: 10.1080/002229300299651, URL: http://www.tandfonline.com/doi/abs/10.1080/00222930029965
L’activité de ponte de la Tortue Luth Dermochelys coriacea (Vandelli, 1761), pendant la saison 1988 en Guyane française
No full textApproximately 48 000 nests of leatherbacks Dermochelys coriacea were counted between March and August 1988 on the Ya:lima:po-Les Hattes beach, French Guiana. This figure represents a new world record for the species. The use of this beach by ovipositing females reached its peak in June, when from 200 to over 1 000 females per night were observed coming ashore.
Marked females were observed laying clutches 8 and 9 times in succession, at intervals of 8 to 32 days : seven females probably laid up to 12 different clutches during the same season.
The total number of leatherbacks nesting at this French Guiana site can be estimated at 14 700-15 300 individuals. The population of leatherbacks nesting in French Guiana is probably larger than previously estimated. The possibility of the nesting cycle of leatherbacks being irregular is also raised.Près de 48 000 nids de Dermochelys coriacea ont été recensés de mars à août 1988 sur la plage de Ya:lima:po-Les Hattes (Guyane française), ce qui représente à nouveau un record de concentration mondiale pour cette espèce. La fréquentation de cette plage atteignit un maximum en juin, le nombre de femelles observées par nuit étant compris entre 200 et 1 000, et dépassant même 1 000 dans une même nuit. Des luths marquées ont été vues et ont pondu 8 et 9 fois à des intervalles de 8 à 32 jours, ce qui laisse supposer un nombre calculé de pontes au moins égal à 12 pour sept des femelles observées. Les auteurs estiment que pendant la saison 1988 la nidification de 14 700 à 15 300 luths a eu lieu, ce qui remet en question la taille du cheptel guyanais total. L’irrégularité du cycle de nidification est discutée.Fretey Jacques, Girondot Marc. L’activité de ponte de la Tortue Luth Dermochelys coriacea (Vandelli, 1761), pendant la saison 1988 en Guyane française. In: Revue d'Écologie (La Terre et La Vie), tome 44, n°3, 1989. pp. 261-274
Apports scientifiques à la conservation des tortues luths en Guyane française
No full textThe leatherback (Dermochelys coriacea) population in French Guiana and Suriname accounts for more than half of the species' females, and the vast majority of them currently nest on Awala-Yalimapo beach. The global population has declined sharply and the leatherback may be the most threatened of all the sea turtles. This makes conservation of the Guyanese population vital, especially since the number of eggs laid in French Guiana has also declined over recent years. The reasons for that decline in French Guiana are not always clear, but certain fishing methods may have a considerable impact. As the situation stands, the scientific work to monitor the population and discover the causes for its decline is cardinal to the Leatherback conservation strategy.La population de tortues luths (Dermochelys coriaced) de Guyane française et du Surinam rassemble plus de la moitié des femelles de l'espèce et la grande majorité de celles-ci pondent actuellement sur la plage de Awala-Yalimapo. Les effectifs mondiaux ont subi un fort déclin et la tortue luth est peut-être la plus menacée de toutes les tortues marines. La conservation du cheptel guyanais est donc primordiale, d'autant plus que le nombre de pontes en Guyane française a lui aussi chuté au cours des dernières années. Les causes de ce déclin en Guyane française ne sont toujours pas bien définies, mais certaines méthodes de pêche pourraient avoir un impact important. Dans la situation actuelle, le travail scientifique comprenant le suivi du cheptel et la recherche des causes du déclin revêt une importance capitale dans la stratégie de conservation des tortues luths.Chevalier Johan, Cazelles Bernard, Girondot Marc. Apports scientifiques à la conservation des tortues luths en Guyane française. In: Journal d'agriculture traditionnelle et de botanique appliquée, 40ᵉ année, bulletin n°1-2,1998. Conserver, gérer la biodiversité : quelle stratégie pour la Guyane ? sous la direction de Marie Fleury et Odile Poncy. pp. 485-507
Lepidochelys olivacea status and its relationship with nest management on the eastern coast in the Pacifico of Guatemala.
Full text linkTesis (Doctorado en Ciencias Naturales para el Desarrollo con énfasis en Gestión y Cultura Ambiental) Instituto Tecnológico de Costa Rica. Universidad Nacional de Costa Rica. Universidad Estatal a Distancia de Costa Rica, Doctorado en Ciencias Naturales para el Desarrollo con énfasis en Gestión de los Recursos Naturales, 2022.Marine turtles are reptiles that have lived in the Earth’s oceans and nested on the
beaches starting several million years ago and also have coexisted with coastal
communities since humans colonized beach areas across the world. In recent
decades, with increased recognition of biodiversity loss and animal extinction,
scientists have focused their research on different conservations strategies for
various taxa. Marine turtles, with their global distribution and widespread occurrence
in various regions, have also been the focus of conservation research and planning.
Marine turtles spend the majority of their lives in the oceans, except for brief periods
associated with reproduction: when females emerge from the ocean to lay eggs in
the sand on open beaches, and when successfully developed hatchlings emerge
from their nests and scramble to the ocean. As beaches are important habitat for
sea turtles, they often are protected globally, with different conservation methods,
and strategies of nest protection have emerged. In Guatemala, nest depredation by
people (also referred to as poaching) has been identified as a threat to sea turtles
since the early 1970s. This problem has led the authorities to establish an exclusive
conservation strategy that focused on protected beach enclosures called hatcheries,
in which sea turtle eggs are reburied for protection and ensure a higher hatching
success (CONAP, 2015). In this system, people collect eggs from freshly laid sea
turtles on various beaches. The egg collectors are required to deliver a “conservation
quota” of 20% of the eggs found in the nest to an officially registered hatchery. In
exchange, they are allowed to keep or sell the remaining eggs for human
consumption or other purposes (CONAP, 2018). This system applies only to the
marine turtle Lepidochelys olivacea, considered the most abundant and constant
nesting species in the Pacific of Guatemala. Commercialization of eggs of other
species is illegal under federal law
Etude des facteurs écologiques et écotoxicologiques impliqués dans la réussite d’incubation chez la tortue luth, Dermochelys coriacea, de Guyane Française
Full text linkLeatherback turtles, Dermochelys coriacea, have relatively low hatching success in
comparison to other marine turtle species. This low hatching rate is largely a result of high embryonic
mortality rather than infertility, but the specific causes remain unknown. Leatherbacks are vulnerable
to excessive adult mortality (resulting in population decline) because they are long-lived species.
However, low hatching success and corresponding low juvenile recruitment could also result in long
term declines of leatherbacks. On the Yalimapo beach, in French Guiana, hatching success is lower for
this species than on other nesting sites, emphasising the problem of recruitment for the population.
Understanding the causes of low hatching success is therefore an important conservation step towards
preventing extinction in this population.
During my thesis, I investigated the role of ecological (predation and nest site location) and
ecotoxicological factors (blood and egg contamination by trace elements and organochlorine
compounds) on the hatching success of leatherback nests. Firstly, nest location was shown to have an
important effect on predation and inundation rate that decreased hatching success. Secondly, a
maternal transfer of contaminants from females to their eggs was confirmed, raising the issue of the
deleterious effects of environmental contaminants on embryos development, a developmental stage
very sensitive to contaminants. Dose-effect relationships between contaminants and hatching success
need to be assessed to establish the risk of environmental pollution for leatherback reproduction.
Moreover, the use of stable isotope analysis for females differing in the number of years between two
reproductive seasons revealed that they used different feeding areas. These feeding grounds differed in
their geographical location, but also in the quality of the available prey in terms of their level of
contamination by environmental pollutants, highlighting the issue of adult contamination.
This thesis confirmed the importance of ecological factors for hatching rate and highlighted
the existence of ecotoxicological factors, which have not yet been studied for the leatherback turtle
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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