1,720,986 research outputs found
Evidence of sirenian cold stress syndrome in dugongs (Digong dugon) from southeast Queensland, Australia
No full textDepredation of eggs of threatened freshwater turtles by the short-beaked echidna (Tachyglossus aculeatus (Shaw, 1792))
No full textThe echidna (Tachyglossus aculeatus) is documented as a new native predator of freshwater turtle eggs, particularly those of the vulnerable Fitzroy River turtle (Rheodytes leukops), and the critically endangered white-throated snapping turtle (Elseya albagula). This depredation has been identified in the Fitzroy, Burnett and Mary Catchments with echidnas recorded at traditional turtle nesting banks using direct observation of depredation of eggs, remote camera footage and identification of tracks. Echidnas were observed at traditional nesting banks for E. albagula and R. leukops nesting across eight months of the year. The presence of echidnas was more frequent during the R. leukops nesting season in spring. R. leukops is endemic to the Fitzroy Catchment and the depredation rate of eggs was significantly higher than for other species and catchments. The mean top egg depth of R. leukops nests was found to be the same depth as the echidna’s beak length. There was a significant increase in depredation during the five-year study period, with 47.4% of R. leukops clutches depredated by echidna in the 2022 season. This substantial loss of eggs and recruitment of hatchling turtles poses a significant threat to the populations of this threatened species.Full Tex
Temporal changes in chemical contamination of green turtles (Chelonia mydas) foraging in a heavily industrialised seaport
No full textPort Curtis, a major shipping port, has undergone significant expansion in the last decade, with plans for further development into the future. These activities may result in an increase of contaminant concentrations, threatening local wildlife including sea turtles. This study used a species-specific in vitro bioassay to examine spatial and temporal differences in exposure to, and effects of, organic contaminants in green sea turtles foraging in Port Curtis. Blood was collected from 134 green sea turtles (Chelonia mydas) from five locations in the port over four years. Organic contaminants were extracted from blood, and the cytotoxicity of the extracts to primary green sea turtle cells was assessed. Results indicated spatially similar chemical contamination throughout Port Curtis, at levels significant to sea turtle health, and with signs that chemical contamination may be increasing over time. These results can provide valuable information on the health of green turtles as further development occurs.Full Tex
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
Sky glow disrupts the orientation of Australian flatback turtles Natator depressus on nesting beaches
No full textLight pollution may disorientate animals at night, resulting in higher mortality and lowered reproductive success. As artificial night lighting ensues from rapid coastal development, there is concern for animals that rely on natural light cues and the coastal environment, such as sea turtles. Their nesting and hatchling emergence generally occurs at night, and nearby artificial lighting can compromise their orientation. Little is known about the impact of sky glow that can be tens of kilometres away from rookeries but visible over the horizon. Here, we investigated how artificial sky glow may impact orientation of hatchling and adult female flatback turtles Natator depressus at four distinct rookeries in Australia. Two orientation parameters, how wide the tracks were spread and how much they deviated from the direct path to or from the ocean, were modelled in a circular and non-circular Bayesian framework. The effects of the moon, cloud cover, rookery, and date were considered. Misorientation of hatchlings, and to a lesser extent adult females, was detected on the rookeries where sky glow was visible from up to ~ 50 km away from the light source. The disruptive impact of the sky glow was slightly mitigated by the moon. There was no evidence of misorientation in the rookery located > 86 km away from major industrial and residential areas. The potential consequences of misorientation, including reduced fitness, are discussed. Our findings suggest careful management of coastal light pollution is imperative to prevent further disruptive impacts of sky glow on a range of sea turtle species.No Full Tex
TakahiroShimada/SDLfilter: 2.1.0 (Major and minor improvements)
No full texto improved the asymptote function.
o added a new citation for functions boot_overlap, boot_area and asymptote. Shimada T, Thums M, Hamann M, Limpus CJ, Hays GC, FitzSimmons NN, Wildermann NE, Duarte CD, Meekan MG (2021) Optimising sample sizes for animal distribution analysis using tracking data. Methods in Ecology and Evolution, 12(2):288-297. doi:10.1111/2041-210X.13506
o updated the README file.
o improved the R documentations of functions asymptote, boot_overlap, and boot_area.
o remaned the example data "curtis" to "flatback"
Combining analytical and in vitro techniques for comprehensive assessments of chemical exposure and effect in green sea turtles (Chelonia mydas)
No full textSea turtle populations foraging in coastal areas adjacent to human activity can be exposed to numerous chemical contaminants for long periods of time. For trace elements, well-developed, sensitive and inexpensive analytical techniques remain the most effective method for assessing exposure in sea turtles. However, there are many thousands more organic contaminants present in sea turtles, often at low levels as complex mixtures. Recently developed species-specific in vitro bioassays provide an effective means to identify the presence, and effect of, organic chemicals in sea turtles. This study used a combination of chemical analysis and effects-based bioassays to provide complementary information on chemical exposure and effects for three green turtle foraging populations (Chelonia mydas) in southern Queensland, Australia. Blood was collected from foraging sub-adult green turtles captured in Moreton Bay, Hervey Bay, and Port Curtis. Twenty-six trace elements were measured in whole blood using ICP-MS. Organic contaminants in turtle blood were extracted via QuEChERS and applied to primary green turtle skin fibroblast cell in vitro assays for two toxicity endpoints; cytotoxicity and oxidative stress. The trace element analysis and bioassay results indicated site-specific differences between foraging populations. In particular, turtles from Moreton Bay, a heavily populated coastal embayment, had pronounced cytotoxicity and oxidative stress from organic blood extracts, and elevated concentrations of Cs, Ag, and Zn relative to the other sites. Incorporating traditional chemical analysis with novel effects-based methods can provide a comprehensive assessment of chemical risk in sea turtle populations, contributing to the conservation and management of these threatened species.No Full Tex
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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