1,720,985 research outputs found
Testosterone and Myelination Data
No full textData included in the publication "Early testosterone exposure during development advances myelination and affects neurogenesis of the vocal control motor path in male zebra finches (Taeniopygia guttata)
No trade-offs between lipid stores and structural growth in juvenile zebra finches undergoing nutritional stress during development
No full textNutritional conditions during development can affect both structural growth and body fat deposition. Body size and body fat each have significant consequences for fitness, yet few studies have investigated how young birds balance resource allocation between structural growth and fat reserves. We raised zebra finches (Taeniopygia guttata) in consistently high- or low-food conditions until posthatch day 35 (PHD 35). From this age until PHD 62, half of the birds in each condition were switched to the other treatment, while the rest were maintained on the same conditions. Body mass, lean mass, body fat, and tarsus length were measured before (PHD 25) and after (PHD 55) nutritional independence. Precise measures of body composition were obtained noninvasively at both ages using quantitative magnetic resonance analysis. At PHD 25, birds in the high treatment had more body mass and lean mass than birds in the low treatment, but nutritional treatments did not affect body fat at this age. Unexpectedly, the strategic response of birds that experienced deteriorating food availability was to maintain body mass by increasing body fat and decreasing lean mass. Birds that experienced an improvement in food availability significantly increased body mass by increasing lean mass and not body fat. Birds maintained on a low diet throughout did not significantly increase body mass, lean mass, or body fat. Tarsus length was not affected by nutritional manipulations. These findings indicate that nutritional stress did not affect the relationship between skeletal growth and body fat deposition because lean mass, body fat, and tarsus length can be independently regulated at different developmental periods depending on nutritional conditions
Responses of White-throated sparrows to simulated winter storm cues
No full textThese data were used in the publication "Increased frequency of exposure to simulated winter storm cues negatively affects white-throated sparrows (Zonotrichia albicollis)" Front. Ecol. Evol. | doi: 10.3389/fevo.2020.00222
Climate change is causing changes in weather patterns and more frequent extreme weather events. Although birds are often able to cope with and respond to inclement weather with physiological and behavioral responses, as weather events become more severe or frequent the adaptive coping responses of many species may be pushed beyond their limits. We investigated the effects of experimental recurrent inclement winter weather cues on body composition, glucocorticoid hormones, and behavior of white-throated sparrows (Zonotrichia albicollis). We used a hypobaric climatic wind tunnel to simulate storms by transiently decreasing barometric pressure and temperature, and measured behavioral responses, body composition, and baseline corticosterone levels in birds exposed, or not exposed (control), to different frequencies of simulated storms. In study 1, experimental birds were exposed to one storm per week over 9 weeks. In study 2, experimental birds were exposed to two storms per week over 12 weeks. Birds exposed to one simulated storm per week had higher fat and lean masses than control birds, with no differences in the amount of time groups spent feeding. This change in body composition suggests that birds were coping by increasing energy stores. In contrast, birds exposed to two simulated storms per week had lower fat masses compared to control birds, even though they spent more time feeding. Experimental birds in study 2 also had lower baseline corticosterone levels than controls. These changes suggest that the coping response observed in study 1 was overcome in study 2. These findings provide novel experimental evidence that birds detect and respond to changes in temperature and barometric pressure independent of other storm-related cues. One simulated storm per week resulted in potentially adaptive responses of increase mass. However, increasing the frequency of storm exposure to twice per week may exceed a physiological threshold for tolerance to which these songbirds are able to cope. These results also experimentally demonstrate that repeated exposure to inclement weather cues can directly affects birds' energy reserves, with strong implications for survival as severe weather events continue to become more prevalent.Unique Bird ID are provided for each data point, along with an indication of the date of the sample and the group (experimental or control) for each bird.
Funding provided by: NSERC Canada*Crossref Funder Registry ID: Award Number: Discovery Grant to S. MacDougall-ShackletonFunding provided by: Animal Behavior SocietyCrossref Funder Registry ID: http://dx.doi.org/10.13039/100009702Award Number: Student Research Grant to A. BoyerFunding provided by: NSERC CanadaCrossref Funder Registry ID: Award Number: Discovery Grant to S. MacDougall-ShackletonFull methods are reported in the open access journal article doi: 10.3389/fevo.2020.00222
Briefly, birds were in control or experimental groups. Experimental birds were exposed to simulated storms and control birds were exposed to ambient conditions. The physiological and behavioural measures collected for studies and 1 and 2 are provided on individal tabs of the worksheet.
Behavioural data were extracted from video recordings using Noldus Ethovision software, as described in the publication.
Body composition data were collected using quantitative magnetic resonance scanning using an EchoMRI body compositoin scanner
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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