475 research outputs found

    Drivers of Cape Verde archipelagic endemism in keyhole limpets

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    Oceanic archipelagos are the ideal setting for investigating processes that shape species assemblages. Focusing on keyhole limpets, genera Fissurella and Diodora from Cape Verde Islands, we used an integrative approach combining molecular phylogenetics with ocean transport simulations to infer species distribution patterns and analyse connectivity. Dispersal simulations, using pelagic larval duration and ocean currents as proxies, showed a reduced level of connectivity despite short distances between some of the islands. It is suggested that dispersal and persistence driven by patterns of oceanic circulation favouring self-recruitment played a primary role in explaining contemporary species distributions. Mitochondrial and nuclear data revealed the existence of eight Cape Verde endemic lineages, seven within Fissurella, distributed across the archipelago, and one within Diodora restricted to Boavista. The estimated origins for endemic Fissurella and Diodora were 10.2 and 6.7 MY, respectively. Between 9.5 and 4.5 MY, an intense period of volcanism in Boavista might have affected Diodora, preventing its diversification. Having originated earlier, Fissurella might have had more opportunities to disperse to other islands and speciate before those events. Bayesian analyses showed increased diversification rates in Fissurella possibly promoted by low sea levels during Plio-Pleistocene, which further explain differences in species richness between both genera.FCT - Portuguese Science Foundation [SFRH/BPD/109685/2015, SFRH/BPD/111003/2015]; Norte Portugal Regional Operational Program (NORTE), under the PORTUGAL Partnership Agreement, through the European Regional Development Fund (ERDF) [MARINFO - NORTE-01-0145-FEDER-000031]info:eu-repo/semantics/publishedVersio

    Hyperdominance in the Amazonian tree flora

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    The vast extent of the Amazon Basin has historically restricted the study of its tree communities to the local and regional scales. Here, we provide empirical data on the commonness, rarity, and richness of lowland tree species across the entire Amazon Basin and Guiana Shield (Amazonia), collected in 1170 tree plots in all major forest types. Extrapolations suggest that Amazonia harbors roughly 16,000 tree species, of which just 227 (1.4%) account for half of all trees. Most of these are habitat specialists and only dominant in one or two regions of the basin. We discuss some implications of the finding that a small group of species--less diverse than the North American tree flora--accounts for half of the world's most diverse tree community.This work was supported by Alberta Mennega Stichting; ALCOA Suriname; Banco de la República; Center for Agricultural Research in Suriname; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Plano Nacional de Pós-Graduação); Conselho Nacional de Desenvovimento Científico e Tecnológico of Brazil (CNPq) projects Programa de Pesquisas Ecológicas de Longa Duração (PELD) (558069/2009-6), Programa de Apoio a Núcleos de Excelência da Fundação de Amparo à Pesquisa do Estado do Amazonas (PRONEX-FAPEAM) (1600/2006), Áreas Úmidas, and MAUA; PELD (403792/2012-6), PPBio, CENBAM, Universal (479599/2008-4), and Universal 307807-2009-6; Fundação de Amparo À Pesquisa Do Estado Do Amazonas (APEAM) projects DCR/2006, Hidroveg with FAPESP, and PRONEX with CNPq; FAPESP; Colciencias; Duke University; Ecopetrol; FEPIM 044/2003; the Field Museum; Conservation International/DC (TEAM/INPA Manuas), Gordon and Betty Moore Foundation; Guyana Forestry Commission; Investissement d’Avenir grant of the French Agence Nationale de la Recherche (ANR) (Centre d’Étude de la Biodiversité Amazonienne ANR-10-LABX-0025); Margaret Mee Amazon Trust; Miquel fonds; National Geographic Society (7754-04, 8047-06 to P.M.J.); Netherlands Foundation for the Advancement of Tropical Research WOTRO grants WB85- 335 and W84-581; Primate Conservation Incorporated; Programme Ecosystèmes Tropicaux (French Ministry of Ecology and Sustainable Development; Shell Prospecting and Development Peru; Smithsonian Institution’s Biological Diversity of the Guiana Shield Program; Stichting het van Eeden-fonds; the Body Shop; the Ministry of the Environment of Ecuador; TROBIT; Tropenbos International; NSF (NSF-0743457 and NSF-0101775 to P.M.J.); USAID; Variety Woods Guyana; WWF-Brazil; WWF-Guianas; XIIéme Contrat de Plan Etat Région-Guyane (French Government and European Union); and grants to RAINFOR from the European Union, UK Natural Environment Research Council, the Gordon and Betty Moore Foundation, and U.S. National Geographic Society. O.L.P. is supported by a European Research Council Advanced Grant and a Royal Society Wolfson Research Merit Award

    Multi-messenger observations of a binary neutron star merger

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    On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

    Teamwork in a coronary care unit: facilitating and hindering aspects

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    Abstract OBJECTIVE To identify, within a multidisciplinary team, the facilitating and hindering aspects for teamwork in a coronary care unit. METHOD A descriptive study, with qualitative and quantitative data, was carried out in the coronary care unit of a public hospital. The study population consisted of professionals working in the unit for at least one year. Those who were on leave or who were not located were excluded. The critical incident technique was used for data collection, by means of semi-structured interviews. For data analysis, content analysis and the critical incident technique were applied. RESULTS Participants were 45 professionals: 29 nursing professionals; 11 physicians; 4 physical therapists; and 1 psychologist. A total of 49 situations (77.6% with negative references); 385 behaviors (54.2% with positive references); and 182 consequences emerged (71.9% with negative references). Positive references facilitate teamwork, whereas negative references hinder it. A collaborative/communicative interprofessional relationship was evidenced as a facilitator; whereas poor collaboration among agents/inadequate management was a hindering aspect. CONCLUSION Despite the prevalence of negative situations and consequences, the emphasis on positive behaviors reveals the efforts the agents make in order to overcome obstacles and carry out teamwork

    A Strong Deletion Bias in Nonallelic Gene Conversion

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    Gene conversion is the unidirectional transfer of genetic information between orthologous (allelic) or paralogous (nonallelic) genomic segments. Though a number of studies have examined nucleotide replacements, little is known about length difference mutations produced by gene conversion. Here, we investigate insertions and deletions produced by nonallelic gene conversion in 338 Drosophila and 10,149 primate paralogs. Using a direct phylogenetic approach, we identify 179 insertions and 614 deletions in Drosophila paralogs, and 132 insertions and 455 deletions in primate paralogs. Thus, nonallelic gene conversion is strongly deletion-biased in both lineages, with almost 3.5 times as many conversion-induced deletions as insertions. In primates, the deletion bias is considerably stronger for long indels and, in both lineages, the per-site rate of gene conversion is orders of magnitudes higher than that of ordinary mutation. Due to this high rate, deletion-biased nonallelic gene conversion plays a key role in genome size evolution, leading to the cooperative shrinkage and eventual disappearance of selectively neutral paralogs

    Can the understory affect the Hymenoptera parasitoids in a Eucalyptus plantation?

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    The understory in forest plantations can increase richness and diversity of natural enemies due to greater plant species richness. The objective of this study was to test the hypothesis that the presence of the understory and climatic season in the region (wet or dry) can increase the richness and abundance of Hymenoptera parasitoids in Eucalyptus plantations, in the municipality of Belo Oriente, Minas Gerais State, Brazil. In each eucalyptus cultivation (five areas of cultivation) ten Malaise traps were installed, five with the understory and five without it. A total of 9,639 individuals from 30 families of the Hymenoptera parasitoids were collected, with Mymaridae, Scelionidae, Encyrtidae and Braconidae being the most collected ones with 4,934, 1,212, 619 and 612 individuals, respectively. The eucalyptus stands with and without the understory showed percentage of individuals 45.65% and 54.35% collected, respectively. The understory did not represent a positive effect on the overall abundance of the individuals Hymenoptera in the E. grandis stands, but rather exerted a positive effect on the specific families of the parasitoids of this order
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