1,174 research outputs found

    Integrating of the seahorse Hippocampus reidi in multi-trophic organic farms of oysters and shrimp: Effects of density and diet

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    The goal of this study was to demonstrate the feasibility of culturing the seahorse Hippocampus reidi in an organic integrated multi-trophic aquaculture farm that produces the oyster Crassostrea brasiliana and the shrimp Litopenaeus vannamei. Experiments were conducted to evaluate the effects stocking density and food (natural zooplankton, Artemia nauplii, or both) for the juvenile I, which are fish from 1 to 15 days after birth. Stocking density effect was studied on growth and survival of juveniles II from 30 days to commercial size in net cages. Survival of the juvenile I was not affected by stocking densities from 2 to 5 ind L-1 and was greater than 70% in all treatments. Seahorse length, however, was inversely related to stocking density. Both treatments with wild zooplankton promoted higher seahorse survival and growth than diet composed exclusively by Artemia sp. during the first 15 days of life. Juvenile II growth decreased with stocking density from 5 to 40 ind m-3 but survival was not affected by it. The total benefit and proportion of colored animals increased significantly with stocking density. The present study confirms the technical feasibility of organic multi-trophic seahorse production in net cages. Even at the highest density tested the seahorses grew well and could generate high profits

    Desempenho de luta e sobrevivência entre espécies de abelhas sem ferrão e abelhas africanizadas em confinamento.

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    Este estudo avaliou o desempenho de luta e a sobrevivência de três espécies de abelhas sem ferrão confinadas com abelhas africanizadas (Apis mellifera)

    WRONG WAY HOME: AN INFANT SOUTHERN ELEPHANT SEAL (MIROUNGA LEONINA) ARRIVAL ON SOUTHEASTERN BRAZILIAN BEACHES

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    ABSTRACTRecords of southern elephant seals (Mirounga leonina) as vagrants along the SE Brazilian coast date back the late 50’s and have been relatively common over the last decades. These large marine mammals usually call much attention when they arrive on tropical beaches worldwide and are generally treated as ‘occasional visitors’ and ‘vagrants’. This note reports on sightings of a youngelephant seal along SE Brazil in the summer and autumn of 2020. We also reviewed records in both the literature and open sources, totaling eight records of infant southern elephant seals known since the late 70’s along the Brazilian coast. It was noted that the arrival of an infant in February of 2020is coincident with a previous cyclonic activity off the SE and NE Brazilian coast. The connection of such unlikely records of pinnipeds on tropical beaches and extreme weather events associated to ocean currents should be better evaluated in the context of climatic change RESUMOÉ reportada uma ocorrência recente de um infante de elefante-marinho (Mirounga leonina) na costa do estado do Rio de Janeiro com um intervalo aproximado de um mês entre as avistagens do mesmo indivíduo. A comparação das fotografias obtidas em ambos os registros permitiu a comparação e confirmação. Em adição, se discute a presença de infantes na costa brasileira, que totalizam oito casos, mas que não apontam uma sazonalidade marcada, mas uma tendência aos registros serem reportados em junho, seguido por outubro e novembro. Como o presente registro se deu em janeiro, pico do verão, fatores climáticos de larga escala podem estar atuando para deslocar alguns indivíduos muito ao longe das suas colônias.Palavras-chave: Mirounga leonina; Movimentos; Vagante; Atlântico Sul

    Chirally symmetric quark description of low energy \pi-\pi scattering

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    Weinberg's theorem for \pi-\pi scattering, including the Adler zero at threshold in the chiral limit, is analytically proved for microscopic quark models that preserve chiral symmetry. Implementing Ward-Takahashi identities, the isospin 0 and 2 scattering lengths are derived in exact agreement with Weinberg's low energy results. Our proof applies to alternative quark formulations including the Hamiltonian and Euclidean space Dyson-Schwinger approaches. Finally, the threshold \pi-\pi scattering amplitudes are calculated using the Dyson-Schwinger equations in the rainbow-ladder truncation, confirming the formal derivation.Comment: 10 pages, 7 figures, Revtex

    Chemodynamical Properties and Ages of Metal-Poor Stars in S-PLUS

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    Metal-poor stars are key to our understanding of the early stages of chemical evolution in the Universe. New multi-filter surveys, such as the Southern Photometric Local Universe Survey (S-PLUS), are greatly advancing our ability to select low-metallicity stars. In this work, we analyse the chemodynamical properties and ages of 522 metal-poor candidates selected from the S-PLUS data release 3. About 92% of these stars were confirmed to be metal-poor ([Fe/H] 1\leq -1) based on previous medium-resolution spectroscopy. We calculated the dynamical properties of a subsample containing 241 stars, using the astrometry from Gaia Data Release 3. Stellar ages are estimated by a Bayesian isochronal method formalized in this work. We analyse the metallicity distribution of these metal-poor candidates separated into different subgroups of total velocity, dynamical properties, and ages. Our results are used to propose further restrictions to optimize the selection of metal-poor candidates in S-PLUS. The proposed astrometric selection (parallax>0.85\mathrm{parallax}>0.85 mas) is the one that returns the highest fraction of extremely metal-poor stars (16.3% have [Fe/H] 3\leq -3); the combined selection provides the highest fraction of very metal-poor stars (91.0% have [Fe/H] 2\leq -2), whereas the dynamical selection (eccentricity > 0.35 and diskness < 0.75) is better for targetting metal-poor (99.5% have [Fe/H] 1\leq -1). Using only S-PLUS photometric selections, it is possible to achieve selection fractions of 15.6%, 88.5% and 98.3% for metallicities below -3, -2 and -1, respectively. We also show that it is possible to use S-PLUS to target metal-poor stars in halo substructures such as Gaia-Sausage/Enceladus, Sequoia, Thamnos and the Helmi stream.Comment: 18 pages, 13 figures. To be published in MNRAS main journal (accepted 15-may-2023

    Estudos paleoambientais interdisciplinares: dinâmica da vegetação, do ambiente marinho e inferências climáticas milenares a atuais na Costa Norte do Espírito Santo, Brasil

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    Estudos paleoambientais desde ~50.000 anos na costa do Brasil e, em particular, no litoral do Espírito Santo, são ainda insuficientes para servir de base a reconstituições da dinâmica da vegetação, de oscilações do nível relativo do mar e de flutuações climáticas e respectivas influências sobre a ação humana milenar. Para obter essas informações, uma equipe interdisciplinar, financiada por projetos temáticos FAPESP e CNPq, desenvolveu pesquisas correlatas na Reserva Natural Vale (RNV) e região. Para a caracterização da dinâmica da vegetação e marinha, com inferências climáticas, em locais de floresta de tabuleiros e campos naturais da RNV e região desde ~16.000 anos, utilizaram-se isótopos do C (12C, 13C e 14C) da matéria orgânica do solo e sedimentar, além de palinologia em sedimentos lacustres e terrestres. No estudo da dinâmica do ecótono floresta – campo, apresentam-se inferências preliminares sobre a evolução pedogenética dos Espodossolos associados ao campo, com ênfase às suas características físico-químicas, e também dos Argissolos, encontrados sob floresta. Finaliza-se com o estágio inicial de uma coleção de referência de fitólitos, bioindicador de vegetação utilizado em estudos paleoambientais, extraídos de plantas da floresta de tabuleiros da RNV.A equipe agradece todo o empenho dos funcionários e apoio logístico da Reserva Natural Vale, Linhares, Espírito Santo; à FAPESP através do projeto Temático 2011/00995-7 (ProjES); e ao CNPq – Universal 2012-5/470210, pelo aporte financeiro e a colaboração dos técnicos do Laboratório 14C, Liz Mary Bueno de Moraes e Thiago Casemiro Barrios de Campos, na preparação de amostras gasosas para a datação 14C.Peer Reviewe

    Drug discovery for Chagas disease should consider Trypanosoma cruzi strain diversity.

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    This opinion piece presents an approach to standardisation of an important aspect of Chagas disease drug discovery and development: selecting Trypanosoma cruzi strains for in vitro screening. We discuss the rationale for strain selection representing T. cruzi diversity and provide recommendations on the preferred parasite stage for drug discovery, T. cruzi discrete typing units to include in the panel of strains and the number of strains/clones for primary screens and lead compounds. We also consider experimental approaches for in vitro drug assays. The Figure illustrates the current Chagas disease drug-discovery and development landscape

    Challenges in the diagnosis and management of acromegaly : a focus on comorbidities

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    Q2Q1Introduction: Acromegaly is a rare, insidious disease resulting from the overproduction of growth hormone (GH) and insulin-like growth factor 1 (IGF-1), and is associated with a range of comorbidities. The extent of associated complications and mortality risk is related to length of exposure to the excess GH and IGF-1, thus early diagnosis and treatment is imperative. Unfortunately, acromegaly is often diagnosed late, when patients already have a wide range of comorbidities. The presence of comorbid conditions contributes significantly to patient morbidity/mortality and impaired quality of life. Methods: We conducted a retrospective literature review for information relating to the diagnosis of acromegaly, and its associated comorbidities using PubMed. The main aim of this review is to highlight the issues of comorbidities in acromegaly, and to reinforce the importance of early diagnosis and treatment. Findings and conclusions: Successful management of acromegaly goes beyond treating the disease itself, since many patients are diagnosed late in disease evolution, they present with a range of comorbid conditions, such as cardiovascular disease, diabetes, hypertension, and sleep apnea. It is important that patients are screened carefully at diagnosis (and thereafter), for common associated complications, and that biochemical control does not become the only treatment goal. Mortality and morbidities in acromegaly can be reduced successfully if patients are treated using a multimodal approach with comprehensive comorbidity management.https://orcid.org/0000-0002-8433-5435N/
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