3,553 research outputs found
Orienting Graphs to Optimize Reachability
The paper focuses on two problems: (i) how to orient the edges of an
undirected graph in order to maximize the number of ordered vertex pairs (x,y)
such that there is a directed path from x to y, and (ii) how to orient the
edges so as to minimize the number of such pairs. The paper describes a
quadratic-time algorithm for the first problem, and a proof that the second
problem is NP-hard to approximate within some constant 1+epsilon > 1. The
latter proof also shows that the second problem is equivalent to
``comparability graph completion''; neither problem was previously known to be
NP-hard
Niche divergence in a brown lemur (' Eulemur ' spp.) hybrid zone : using ecological niche models to test models of stability
Variation de la masse et des caractères morphologiques des lémuriens nocturnes dans les forêts primaires et dégradées de Menabe Sud, Belo sur Mer, Madagascar
Forest structure effects primate morphology because it determines the availability and characteristics of resources, such as substrates for locomotion, sleeping trees, and trees food. However, forest degradation may alter environmental condition of habitats and influence lemur behavior and morphology. We evaluated the links between forest degradation, lemur body mass, and lemur morphometric. We surveyed red-tailed sportive lemurs (Lepilemur ruficaudatus) and gray mouse lemurs (Microcebus murinus) in the dry, deciduous forest of southern Menabe, Morondava, Madagascar. The study was conducted in the dry season in 2014 (November–December) and 2015 (July–September). Lemur captures were conducted in five forest sites: two primary forest and three disturbed forest. Sherman and Tomahawk style traps were used to capture mouse lemurs. We conducted three capture sessions in site B in 2014 and three capture sessions for each site in 2015, for a total of 5616 night traps. During each capture session, 80 Sherman traps and 24 Tomahawk traps were installed for three consecutive nights. To capture the red-tailed sportive lemur, we used a gun (Dan Inject Model JM air rifle) with a tranquillizer dart to immobilize the animal. We collected morphometric measurements from 232 mouse lemurs and 31 red-tailed sportive lemurs. Botanic plots (5m x 5m) allowed us to characterize the forest characteristics: tree diameter at breast height (DBH), tree height, tree abundance, tree crown height and diameter. Tree abundance with DBH ≥ 5 cm and trees diversity varied significantly between sites (P < 0.001). Mouse lemur body mass did not vary with seasonality of the capture (P > 0.05). For mouse lemurs, all morphometric from two populations in the pristine forest were similar (P > 0.05). Mouse lemurs in one disturbed habitat had greater body length and body mass than mouse lemurs in the pristine forest (P < 0.05). The difference may be linked with fruit abundance of two trees species (Tamarindus indica and Ziziphus mauritiana) and more insect availability in the disturbed site. In the altered habitat, mouse lemur females had longest body size and heavier than males (P < 0.05). Red-tailed sportive lemur body mass and length did not change between sites (P > 0.05). Our study is consistent with the hypothesis that lemur morphometric and body mass may change with forest degradation in southern forest of Menabe. Additionally, the range of the response varies between species and sex: mouse lemurs had a wider reaction norm to the habitat disturbance than did red-tailed sportive lemurs. Mouse lemurs may have higher ecological flexibility and tolerance for forest changes, specifically the alteration of forest habitats. Understanding how lemur morphology responds to habitat disturbance may be used as a tool to prioritize lemur conservation.
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Résumé
La perte d’habitat due à l’activité humaine est une menace qui affecte tous les primates à Madagascar. Les lémuriens, primates arboricoles, ont des réponses variées face au changement de leur habitat. La présente recherche vise à déterminer le lien entre la dégradation forestière, la masse et les caractères morphologiques des lémuriens nocturnes de Menabe Sud : Lepilemur ruficaudatus et Microcebus murinus. L’étude a été effectuée dans cinq sites dont deux sites sont des forêts primaires et trois autres sont des forêts perturbées. La capture et la mesure des caractères morphologiques des lémuriens ont été réalisées entre novembre et décembre 2014, puis entre juillet et septembre 2015. Des parcelles botaniques (5m x 5m) ont été utilisées pour décrire les caractéristiques des sites dont l’abondance des arbres, le diamètre à hauteur de poitrine ou la hauteur et le diamètre de la couronne. La masse de M. murinus n’était pas influencée par la saison de capture (P > 0,05), mais elle variait avec le sexe (P < 0,005) et le site (P < 0,001). Tous les caractères morphologiques de M. murinus dans les deux forêts primaires étaient similaires (P > 0,05). Par contre, dans les forêts perturbées, les femelles de M. murinus étaient plus lourdes et avaient des corps plus longs que les mâles (P < 0,05). La masse et la longueur du corps de L. ruficaudatus entre les différents sites étaient similaires (P > 0,05). Comparé à L. ruficaudatus, M. murinus répondrait davantage à la dégradation forestière. Comprendre l’étendue de la réponse morphologique des lémuriens face à la dégradation de leur habitat pourrait être utilisé comme outil pour prioriser leur conservation
Soil and Water Conservation and Management Research at the Wheatland Conservation Experiment Station
The Oklahoma Agricultural Experiment Station periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311
Hybrid Corn Strains Recommended for 1954
The Oklahoma Agricultural Experiment Station periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311
Fertilization of Native Grass Pasture on Eroded and Brush Land at the Red Plains Conservation Experiment Station
The Oklahoma Agricultural Experiment Station periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311
5th Annual Field Day Kiamichi Field Station
The Oklahoma Agricultural Experiment Station periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311
Planter Boxes Recommended for Planting Castor Beans
The Oklahoma Agricultural Experiment Station periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311
Soil and Water Conservation and Management Research at the Red Plains Conservation Experiment Station
The Oklahoma Agricultural Experiment Station periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311
Revision of Madagascar's Dwarf Lemurs (Cheirogaleidae:Cheirogaleus): Designation of Species, Candidate Species Status and Geographic Boundaries Based on Molecular and Morphological Data
The genus Cheirogaleus, the dwarf lemurs, is a radiation of strepsirrhine primates endemic to the island of Madagascar.
The dwarf lemurs are taxonomically grouped in the family Cheirogaleidae (Infraorder: Lemuriformes) along with the genera
Microcebus, Mirza, Allocebus, and Phaner. The taxonomic history of the genus Cheirogaleus has been controversial since its
inception due to a paucity of evidence in support of some proposed species. In this study, we addressed this issue by expanding the
geographic breadth of samples by 91 individuals and built upon existing mitochondrial (cytb and COII) and nuclear (FIBA and
vWF) DNA datasets to better resolve the phylogeny of Cheirogaleus. The mitochondrial gene fragments D-loop and PAST as well
as the CFTR-PAIRB nuclear loci were also sequenced. In agreement with previous genetic studies, numerous deep divergences
were resolved in the C. major, C. minor and C. medius lineages. Four of these lineages were segregated as new species, seven
were identified as confirmed candidate species, and four were designated as unconfirmed candidate species based on comparative
mitochondrial DNA sequence data gleaned from the literature or this study. Additionally, C. thomasi was resurrected. Given the
widespread distribution of the genus Cheirogaleus throughout Madagascar, the methodology employed in this study combined
all available lines of evidence to standardize investigative procedures in a genus with limited access to type material and a lack of
comprehensive sampling across its total distribution. Our results highlighted lineages that likely represent new species and identified
localities that may harbor an as-yet undescribed cryptic species diversity pending further field and laboratory work.We
are most grateful to the Ahmanson Foundation, the Theodore
F. and Claire M. Hubbard Family Foundation, the Primate
Action Fund / Conservation International, the Margot
Marsh Biodiversity Foundation, and the National Geographic
Society, for financial assistance
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