1,720,988 research outputs found
Seasonality and Behavioral Energy Strategies in Microcebus berthae and M. murinus
No full textTo survive and reproduce successfully in highly seasonal regions, animals must balance their energy budgets during lean seasons. We conducted a comparative study of two sympatric mouse lemur species to identify species-specific energy saving strategies for coping with seasonality and evaluated their consequences for female fitness. Since August 2002 we captured, marked and recaptured individuals of coexisting populations of Microcebus berthae and M. murinus in Kirindy Forest and recorded activity by direct observations of radio-collared females. The species differed in their seasonal activity patterns: female M. berthae maintained high activity levels throughout the year, whereas female M. murinus largely ceased activity during the cold dry season. In M. berthae, low survival restricted female reproductive potential. Consequently, females maximized the condition in which they entered the reproductive season. In contrast, M. murinus females maximized survival but entered the reproductive season in poor condition. Thus, mouse lemur species subjected to the same environmental conditions show different species-specific behavioral energy strategies to cope with pronounced seasonality
Seasonality and behavioural energy in Microcebus berthae and M. murinus
No full textTo survive and reproduce successfully in highly seasonal regions, animals must balance their energy budgets during lean seasons. We conducted a comparative study of two sympatric mouse lemur species to identify species-specific energy saving strategies for coping with seasonality and evaluated their consequences for female fitness. Since August 2002 we captured, marked and recaptured individuals of coexisting populations of Microcebus berthae and M. murinus in the Kirindy Forest and recorded activity by direct observations of radio-collared females. The species differed in their seasonal activity patterns: female M. berthae maintained high activity levels throughout the year, whereas female M. murinus all but ceased activity during the cold dry season. In M. berthae, low survival restricted female reproductive potential. Consequently, females maximized the condition in which they entered the reproductive season. In contrast, M. murinus females maximized survival but entered the reproductive season in poor condition. Thus, mouse lemur species subjected to the same environmental conditions show different species-specific energetic strategies to cope with pronounced seasonality
Noises in the Dark: Vocal Communication in Lepilemur ruficaudatus and Other Nocturnal Pair-Living Primates
No full textAlthough the number of pair-living species is higher in nocturnal than in diurnal primates, less is known about the communicative function of their vocalizations. One striking feature of vocal communication in diurnal pair-living primates is that partners exchange vocalizations in coordinated duets. Several functions have been attributed to duets, including mate attraction, advertizing and strengthening the pair bond, and territorial defense. To assess whether these functions can also be attributed to vocalizations of pair-living nocturnal primates, we studied the communicative function of vocalizations of red-tailed sportive lemurs (Lepilemur ruficaudatus). Social interactions between partners were equally often accompanied by vocal exchanges or not. Half of these vocal interactions included mutual but not coordinated exchanges of vocalizations between partners. In addition, playback experiments with vocalizations of the respective partner did not elicit vocal responses. Thus, exchanges of vocalizations might function to regulate spacing and interactions within pairs rather than to advertize or strengthen pair bonds. Since Lepilemur ruficaudatus interacted more often vocally with partners than with neighbors, and also vocalized when alone, we conclude that calling serves to signal an animal’s presence in its territory and to regulate spacing among conspecifics. Because vocalizations seem to serve in territorial defense in most nocturnal pair-living primates, cohesiveness between partners may have been the initial driving force behind the evolution of duets
Seasonality and behavioural energy in Microcebus berthae and M. murinus
No full textTo survive and reproduce successfully in highly seasonal regions, animals must balance their energy budgets during lean seasons. We conducted a comparative study of two sympatric mouse lemur species to identify species-specific energy saving strategies for coping with seasonality and evaluated their consequences for female fitness. Since August 2002 we captured, marked and recaptured individuals of coexisting populations of Microcebus berthae and M. murinus in the Kirindy Forest and recorded activity by direct observations of radio-collared females. The species differed in their seasonal activity patterns: female M. berthae maintained high activity levels throughout the year, whereas female M. murinus all but ceased activity during the cold dry season. In M. berthae, low survival restricted female reproductive potential. Consequently, females maximized the condition in which they entered the reproductive season. In contrast, M. murinus females maximized survival but entered the reproductive season in poor condition. Thus, mouse lemur species subjected to the same environmental conditions show different species-specific energetic strategies to cope with pronounced seasonality
A multilocus phylogeny reveals deep lineages within African galagids (Primates: Galagidae)
No full textBackground Bushbabies (Galagidae) are among the most morphologically cryptic of all primates and their diversity and relationships are some of the most longstanding problems in primatology. Our knowledge of galagid evolutionary history has been limited by a lack of appropriate molecular data and a paucity of fossils. Most phylogenetic studies have produced conflicting results for many clades, and even the relationships among genera remain uncertain. To clarify galagid evolutionary history, we assembled the largest molecular dataset for galagos to date by sequencing 27 independent loci. We inferred phylogenetic relationships using concatenated maximum-likelihood and Bayesian analyses, and also coalescent-based species tree methods to account for gene tree heterogeneity due to incomplete lineage sorting. Results The genus Euoticus was identified as sister taxon to the rest of the galagids and the genus Galagoides was not recovered as monophyletic, suggesting that a new generic name for the Zanzibar complex is required. Despite the amount of genetic data collected in this study, the monophyly of the family Lorisidae remained poorly supported, probably due to the short internode between the Lorisidae/Galagidae split and the origin of the African and Asian lorisid clades. One major result was the relatively old origin for the most recent common ancestor of all living galagids soon after the Eocene-Oligocene boundary. Conclusions Using a multilocus approach, our results suggest an early origin for the crown Galagidae, soon after the Eocene-Oligocene boundary, making Euoticus one of the oldest lineages within extant Primates. This result also implies that one – or possibly more – stem radiations diverged in the Late Eocene and persisted for several million years alongside members of the crown group
Phylogenetic relationships among the Lorisoidea as indicated by craniodental morphology and mitochondrial sequence data
No full textGoing 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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