1,720,982 research outputs found
Diet of South Polar Skua chicks in two areas of sympatry with Brown Skua
Full text linkThe food provided to South Polar Skuas (Stercorarius maccormicki) chicks was determined at two Antarctic sites where South Polar Skuas breed sympatrically with Brown Skuas (S. antarcticus). At Harmony Point on Nelson Island, 16 samples of regurgitated stomach contents were analyzed, all contained remains of penguin chicks (mostly soft tissues), which constituted the bulk of the contents, while only two samples had fish or krill remains. These South Polar Skuas had access to penguin colonies, where they hunted chicks or fed on fresh carcasses. However, at Half Moon Island, only two out of nine samples contained minor amounts of penguin remains while fish were the major dietary resource. The high fish content in their diet may indicate a preference for marine rather than terrestrial resources or be the result of competition with Brown Skuas. The variability in food items evidenced by the differences in regurgitated stomach contents indicates that South Polar Skuas may have a trophic plasticity that allows them to change their feeding habits from one resource to another one according to availability. Such may make them less vulnerable to a reduction in the availability of a particular food item.Fil: Graña Grilli, Maricel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Libertelli, Marcela. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Montalti, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Ornitología; Argentin
Blood parameters of emperor penguin Aptenodytes forsteri chicks at their northernmost Antarctic colony
Full text linkThe emperor penguin (Aptenodytes forsteri) is one of the penguins most threatened by global warming therefore, it is important to monitor physical condition of individuals, especially in the colonies spread further north where the effect of climate change is greater. Here, we present blood and biochemical markers of the general physical condition related to health, nutrition and immune function of emperor penguin chicks at Cerro Nevado/Snow Hill Island, Antarctica, the northernmost colony of their distribution, during the winter season of 2014. We determined the leukocyte counts, the heterophil / lymphocyte ratio and the concentrations of glucose, cholesterol and triglycerides in emperor penguin chicks. These data constitute the first report in chicks of emperor penguins at this location.Fil: D'amico, Veronica Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Libertelli, Marcela. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Coria, Néstor Rubén. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bertellotti, Néstor Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentin
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
Breeding success and population trends in Adélie penguins in areas with low and high levels of human disturbance
No full textThe breeding performance and population trends of Adélie penguins (Pygoscelis adeliae) was studied at Esperanza/Hope Bay, Antarctic Peninsula, by comparing an area with low levels of human disturbance (LLD) and an area with high levels of human disturbance (HLD), close to an Argentine research station. From 1995/1996 to 2004/2005 (except for 1999/2000 and 2003/2004), the following population parameters were measured in both areas: (1) the number of breeding pairs, (2) the number of chicks in crèches and (3) the number of chicks produced by breeding pairs.Counts were made for 26 breeding groups situated in the LLD area and 63 breeding groups located in the HLD area. The number of chicks per breeding pair was obtained by following 100 marked nests in each area. All parameters were measured as described in the CCAMLR Monitoring Program protocols. The magnitude and direction (increasing or decreasing) of the changes in breeding population size and the number of chicks crèched were similar in both areas. Overall, the number of breeding pairs decreased from 4,744 to 2,968 (37.4%) in the LLD area, and from 8,744 to 5,378 (38.6%) in the HLD area. The number of chicks fledged increased from 3,808 to 4,065 (6.7%) in the LLD area, and decreased from 6,991 to 6,712 (4%) in the HLD area. Breeding success (chicks fledged per marked nest) did not differ significantly between areas for most of the seasons compared. In 1996/1997, breeding success was significantly higher in the HLD area.Our data suggest that environmental influences currently exert greater effects than human disturbance on the penguin population at Esperanza Bay.Fil: Carlini, A. R.. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Coria, Néstor Rubén. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Santos, Maria Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Libertelli, Marcela Mónica. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Donini, G.. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentin
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
Physiology data from Wilson's Storm-petrel chicks from breeding seasons 2015 - 2017 at King George Island, Antarctica
No full textThis data set contains the physiological data of Wilson's Storm-petrel (Oceanites oceanicus, https://www.marinespecies.org/aphia.php?p=taxdetails&id=137190) chicks at a breeding colony on King George Island (Islas 25 de Mayo, Antarctica), close to the Argentinian Base Carlini (62°14′S, 58°40′W; formerly called Base Jubany). Data was collected during three breeding seasons (2015 – 2017) to study influence of body temperature on developmental parameters. Age was determined by tarsus length following Quillfeldt & Peter (2000, doi:10.1007/s003000000158). During regular nest checks starting five days after estimated hatching date, body temperature and weight were measured daily, tarsus and wing length were determined every three days. Blood samples of maximum 70 μl were taken from the wing vein using 24 G single use hypodermic needles (Sterican© Braun), and disposable heparinized micro-haematocrit capillaries (Hirschmann®). The first blood sample was taken when chicks were at least nine days old and reached a body weight of 25 g. Following samples were taken weekly. Phytohemagglutinin assays were conducted in chicks aged 48 to 52 days. The sex of chicks was determined by molecular analysis based on blood samples dried on FTA ® (WhatmanTM) classic cards following Griffiths et al. (1998). Detailed descriptions of laboratory protocols can be found in Kuepper et al. (in prep)
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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