744 research outputs found

    Spherical linear waves in de Sitter spacetime

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    We apply Christodoulou's framework, developed to study the Einstein-scalar field equations in spherical symmetry, to the linear wave equation in de Sitter spacetime, as a first step towards the Einstein-scalar field equations with positive cosmological constant. We obtain an integro-differential evolution equation which we solve by taking initial data on a null cone. As a corollary we obtain elementary derivations of expected properties of linear waves in de Sitter spacetime: boundedness in terms of (characteristic) initial data, and a Price law establishing uniform exponential decay, in Bondi time, to a constant.Comment: 9 pages, 1 figure; v2: minor changes, references added, matches final published versio

    Contaminação por mercúrio em sedimento e moluscos da Bacia do rio Bento Gomes, MT.

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    Os níveis de mercúrio total detectados no sedimento e tecidos moles de moluscos gastrópodos provenientes da bacia hidrográfica do rio Bento Gomes, embora baixos, mostraram indícios de contaminação. De um total de 69 amostras de sedimento analisadas, 26% apresentaram níveis de mercúrio total variando de 0,01 a 0,25 µg.g-1 de mercúrio (peso úmido). Os níveis de mercúrio obtidos em 54 amostras dos moluscos Ampullaria scalaris; A. canaliculata e Marisa planogira evidenciaram que 39% estavam contaminadas com níveis variando de 0,02 a 1,6 µg.g-1 de peso úmido. Estes resultados indicam que o mercúrio utilizado na extração de ouro de aluvião está atingindo o ambiente aquático e contaminado o sedimento e os organismos bentônicos desta área do Pantanal.bitstream/item/37304/1/BP58.pd

    Managing arbuscular mycorrhizal fungi for bioprotection: Mn toxicity

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    We investigated whether an intact extraradical mycelium (ERM) is more effective than other forms of propagule from indigenous arbuscular mycorrhizal fungi (AMF) in providing protection against stress to a host plant. The response of wheat (Triticum aestivum L.) to Mn toxicity was studied in a two-phase greenhouse experiment. In Phase 1, four Mn tolerant species from the natural vegetation, ranging from strongly mycotrophic to non- or weakly mycotrophic, were grown to develop different amounts of ERM. Wheat was then planted (Phase 2) with the ERM fragmented by sieving (Disturbed Treatment) or kept intact with no prior soil disturbance (Undisturbed Treatment). The growth of wheat was doubled by earlier and faster mycorrhizal colonization (AC) in the presence of an intact ERM at planting. There was a positive correlation between plant growth and the reduction of Mn and enhancement of P and S uptake into shoots. However, the growth of plants in undisturbed soil was significantly affected by the ERM developer species, which was not explained by differences in AC. Colonization starting from an intact ERM greatly enhanced the potential of AMF for protection against Mn toxicity. However, the degree of protection depended on the plant previously grown to develop the ERM, suggesting that there may be functional diversity within the ERM developed by mycotrophic plants of the natural vegetation

    Interaction between Arbuscular Mycorrhizal Fungi and rhizobia on the growth of subclover under Mn toxicity: The role of Extraradical Mycelium.

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    When Arbuscular Mycorrhizal (AM) colonization started from an intact extraradical mycelium (ERM) its bioprotective effect on subclover was enhanced in comparison with other sources of inoculum. The presence in the soil of an intact ERM, developed previously on mycotrophic plants tolerant to Mn toxicity, resulted in the earlier colonization of subclover, reduced Mn concentration in the roots, improved development and activity of root nodules, and enhanced N acquisition

    Bat-species richness in the Pantanal floodplain and its surrounding uplands

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    Estudamos a fauna de morcegos na planície do Pantanal e nos planaltos de entorno no Mato Grosso do Sul, Brasil, com base na coleção científica da Universidade Anhanguera – Uniderp e no banco de dados do Projeto Morcegos do Pantanal, UFMS, incluindo 9.037 capturas de 56 espécies, entre 1994 e 2007. Amostragens no Pantanal foram feitas nas sub-regiões da Nhecolândia, Aquidauana, Miranda e Paraguai; no planalto as amostragens foram realizadas nas formações de Maracaju, Bodoquena e Urucum. Espécies de morcegos foram registradas ao longo de 376 noites em 35 sítios, predominantemente com o uso de redes de neblina próximas a árvores frutíferas, abrigos e florestas. Na planície, foram registradas 46 espécies (n = 6.292 indivíduos) e no planalto 44 espécies (n = 2.745 indivíduos). Seis famílias foram encontradas: Phyllostomidae (30 espécies), Molossidae (12 espécies), Verpertilionidae (nove espécies), Noctilionidae (duas espécies), Emballorunidae (duas espécies) e Mormoopidae (uma espécie). A fauna de morcegos foi predominantemente composta de espécies insetívoras (32) e frugívoras (15). O frugívoro Artibeus planirostris (n = 3.101) foi a espécie mais comum na planície e no planalto. Outras espécies comuns foram Myotis nigricans (n = 762), Molossus molossus (n = 692), Noctilio albiventris (n = 681), Platyrrhinus lineatus (n = 633), Sturnira lilium (n = 461), Carollia perspicillata (n = 451), Glossophaga soricina (n = 436), Artibeus lituratus (n = 320) e Desmodus rotundus (n = 281). Na planície, ocorreram três espécies de morcegos insetívoros dentre as espécies mais comuns, contrastando com o planalto, onde houve dominância de frugívoros. A diversidade para os 35 sítios reunidos (H’ = 2,5) é comparável à encontrada em florestas tropicais. A fauna de morcegos apresentada aqui representa 34% das espécies brasileiras, e 62% das espécies já reportadas para a Bacia do Alto Paraguai. Adicionalmente, cinco espécies são reportadas pela primeira vez no Mato Grosso do Sul. ________________________________________________________________________________________ ABSTRACTWe studied the bat fauna of the Pantanal floodplain and its surrounding plateaus in Mato Grosso do Sul, Brazil, based on the scientific collection at Universidade Anhanguera – Uniderp and on the Projeto Morcegos do Pantanal data bank at UFMS, comprising 9,037 captures of 56 species recorded from 1994 to 2007. The Pantanal surveys were carried out in the Nhecolândia, Aquidauana, Miranda, and Paraguai sub-regions; the uplands surveys took place in the Maracaju, Bodoquena, and Urucum formations. Bat specimens were mist-netted over 376 nights in 35 sites, predominantly near fruiting trees, bat shelters, and forest patches. In the floodplain 46 species were recorded (n = 6,292 individuals), and 44 species were found in the uplands (n = 2,745 individuals). Six families were recorded: Phyllostomidae (30 species), Molossidae (12 species), Verpertilionidae (nine species) Noctilionidae (two species), Emballorunidae (two species) and Mormoopidae (one species). The bat fauna was predominantly composed of insectivore (32) and frugivore (15) species. The frugivorous Artibeus planirostris (n = 3,101 individuals) was the commonest species in floodplain and uplands. Other common species were Myotis nigricans (n = 762), Molossus molossus (n = 692), Noctilio albiventris (n = 681), Platyrrhinus lineatus (n = 633), Sturnira lilium (n = 461), Carollia perspicillata (n = 451), Glossophaga soricina (n = 436), Artibeus lituratus (n = 320), and Desmodus rotundus (n = 281). In the floodplain there were three insectivores among the most common species, contrasting with the uplands dominated by the frugivores. The diversity for the 35 sites assembled (H’ = 2.5) is comparable to that recorded for tropical forests. The bat fauna presented here represents 34% of the Brazilian bat species, and 62% of species reported for the Upper Paraguay River Basin. Additionally, five species are reported for the first time in Mato Grosso do Sul

    Revealing the foraging movements and diet of the White-faced Storm Petrel Pelagodroma marina in the NE Atlantic

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    The White-faced Storm Petrel (WFSP) Pelagodroma marina has a widespread distribution, although virtually nothing is known about their feeding ecology and distributions at-sea. To describe their foraging areas, a total of 77 birds were equipped with 1 g-GPS loggers on Selvagem Grande, Madeira, Portugal (30° 09′ N, 15° 52′ W), during the 2018 and 2019 breeding seasons. We also assessed the diet of WFSP by analysing 17 faecal samples from chicks and 1 regurgitation from an adult using DNA metabarcoding techniques. Additionally, we collected body feathers from ten WFSP chicks to determine mercury concentration. WFSP fed mainly in deep oceanic waters, travelling up to 400 km from the colony, and did not concentrate in any well-defned, population-level foraging hotspots. Some individuals foraged along the edge of the shelf, near the African coast and the Canary Islands, especially during chick rearing. The duration of foraging trips and the total distance travelled, were, on average, 5.1 days and 723 km during the incubation period and 3.0 days and 578 km during chick rearing. The diet of WFSP was dominated by fsh and cephalopods (crustacean prey were not detected), with Myctophidae (FO=71%) representing the main fsh family. WFSP often consume mesopelagic fsh, in line with their preference for deep oceanic waters and with a small diference in at sea behavior (i.e., travel speed) between the diurnal and nocturnal period. The relatively high concentrations of mercury accumulated in body feathers of WFSP chicks (3.45±1.44 mg kg−1 dry weight; range 1.68–6.01 mg kg−1) support the idea that WFSP raise their chicks mostly on mesopelagic prey from deep pelagic areas.CESAM; Fundação para a Ciência e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio

    Influence of body odors and gender on perceived genital arousal

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    Olfaction is often linked to mating behavior in nonhumans. Additionally, studies in mating behavior have shown that women seem to be more affected by odor cues than men. However, the relationship between odor cues and sexual response—specifically, sexual arousal—has not been studied yet. The aim of this study was to evaluate the impact of the exposure to human body odors (from individuals of the opposite gender) on perceived genital arousal, while these were presented concomitantly to sexually explicit video clips. Eighty university students (40 women) rated their perceived genital arousal (perceived degree of erection/genital lubrication) in response to an audiovisual sexual stimulus, while simultaneously exposed to a body odor from an opposite-gender donor or no odor. Participants also rated each odor sample’s (body odor and no odor) perceived pleasantness, intensity, and familiarity. Findings indicated that odor condition had an effect on women’s (but not men’s) perceived genital arousal, with women showing higher levels of perceived genital arousal in the no odor condition. Also, results showed that women rated body odors as less pleasant than no odor. Notwithstanding, the odor ratings do not seem to explain the association between body odor and perceived genital arousal. The current results support the hypothesis that women, rather than men, are sensitive to odors in the context of sexual response. The findings of this study have relevance for the understanding of human sexuality with respect to chemosensory communicationinfo:eu-repo/semantics/acceptedVersio
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