209 research outputs found

    Absolute properties of the low-mass eclipsing binary CM Draconis

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    Spectroscopic and eclipsing binary systems offer the best means for determining accurate physical properties of stars, including their masses and radii. The data available for low-mass stars have yielded firm evidence that stellar structure models predict smaller radii and higher effective temperatures than observed, but the number of systems with detailed analyses is still small. In this paper we present a complete reanalysis of one of such eclipsing systems, CM Dra, composed of two dM4.5 stars. New and existing light curves as well as a radial velocity curve are modeled to measure the physical properties of both components. The masses and radii determined for the components of CM Dra are M1=0.2310+/-0.0009 Msun, M2=0.2141+/-0.0010 Msun, R1=0.2534+/-0.0019 Rsun, and R2=0.2396+/-0.0015 Rsun. With relative uncertainties well below the 1% level, these values constitute the most accurate properties to date for fully convective stars. This makes CM Dra a valuable benchmark for testing theoretical models. In comparing our measurements with theory, we confirm the discrepancies reported previously for other low-mass eclipsing binaries. These discrepancies seem likely to be due to the effects of magnetic activity. We find that the orbit of this system is slightly eccentric, and we have made use of eclipse timings spanning three decades to infer the apsidal motion and other related properties.Comment: 19 pages, 9 figures. Accepted for publication in Ap

    Zoneamento edafoclimático da cultura do melão

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    A cultura do melão é uma das culturas hortícolas brasileiras, devido ao seu potencial produtivo e papel sócio econômico. Sendo de fácil e tendo necessidade de zoneamento das condições climáticas e assim recomendar para o Estado de Goiás e o Distrito Federal, podendo assim realizar sua semeadura. O presente trabalho utilizou o programa Sarazon para a realização do balanço hídrico da cultura do melão, para as datas de semeadura do 2º, 4º e 6º quinquídios dos meses de agosto, setembro e outubro e relação às reservas de água no solo de 50 mm e 75 mm. Os dados foram espacializados utilizando-se o programa SPRING 4.3. Observou-se que os produtores estão realizando na pratica o que pode ser demonstrado na teoria que o período de 16-20 de outubro é o mais indicado para semeadura em solos de 50 mm de reserva de água e 06-10 de outubro o início da semeadura em solo de 75 mm de reserva de água para o cultivo do melão e ter adequada rentabilidade

    Dietary betaine supplementation increases Fgf21 levels to improve glucose homeostasis and reduce hepatic lipid accumulation in mice

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    Identifying markers of human insulin resistance may permit development of new approaches for treatment and prevention of type 2 diabetes. To this end, we analyzed the fasting plasma metabolome in metabolically characterized human volunteers across a spectrum of insulin resistance. We demonstrate that plasma betaine levels are reduced in insulin-resistant humans and correlate closely with insulin sensitivity. Moreover, betaine administration to mice with diet-induced obesity prevents the development of impaired glucose homeostasis, reduces hepatic lipid accumulation, increases white adipose oxidative capacity, and enhances whole-body energy expenditure. In parallel with these beneficial metabolic effects, betaine supplementation robustly increased hepatic and circulating fibroblast growth factor (Fgf)21 levels. Betaine administration failed to improve glucose homeostasis and liver fat content in Fgf21(-/-) mice, demonstrating that Fgf21 is necessary for betaine's beneficial effects. Together, these data indicate that dietary betaine increases Fgf21 levels to improve metabolic health in mice and suggest that betaine supplementation merits further investigation as a supplement for treatment or prevention of type 2 diabetes in humans

    That anthropology was not for us

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    Special interview - Cadernos de Campo - 25 year

    Replication competent retrovirus testing (RCR) in the National Gene Vector Biorepository: No evidence of RCR in 1,595 post-treatment peripheral blood samples obtained from 60 clinical trials

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    The clinical impact of any therapy requires the product be safe and effective. Gammaretroviral vectors pose several unique risks, including inadvertent exposure to replication competent retrovirus (RCR) that can arise during vector manufacture. The US FDA has required patient monitoring for RCR, and the National Gene Vector Biorepository is an NIH resource that has assisted eligible investigators in meeting this requirement. To date, we have found no evidence of RCR in 338 pre-treatment and 1,595 post-treatment blood samples from 737 patients associated with 60 clinical trials. Most samples (75%) were obtained within 1 year of treatment, and samples as far out as 9 years after treatment were analyzed. The majority of trials (93%) were cancer immunotherapy, and 90% of the trials used vector products produced with the PG13 packaging cell line. The data presented here provide further evidence that current manufacturing methods generate RCR-free products and support the overall safety profile of retroviral gene therapy

    A chemical survey of exoplanets with ARIEL

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    Thousands of exoplanets have now been discovered with a huge range of masses, sizes and orbits: from rocky Earth-like planets to large gas giants grazing the surface of their host star. However, the essential nature of these exoplanets remains largely mysterious: there is no known, discernible pattern linking the presence, size, or orbital parameters of a planet to the nature of its parent star. We have little idea whether the chemistry of a planet is linked to its formation environment, or whether the type of host star drives the physics and chemistry of the planet’s birth, and evolution. ARIEL was conceived to observe a large number (~1000) of transiting planets for statistical understanding, including gas giants, Neptunes, super-Earths and Earth-size planets around a range of host star types using transit spectroscopy in the 1.25–7.8 μm spectral range and multiple narrow-band photometry in the optical. ARIEL will focus on warm and hot planets to take advantage of their well-mixed atmospheres which should show minimal condensation and sequestration of high-Z materials compared to their colder Solar System siblings. Said warm and hot atmospheres are expected to be more representative of the planetary bulk composition. Observations of these warm/hot exoplanets, and in particular of their elemental composition (especially C, O, N, S, Si), will allow the understanding of the early stages of planetary and atmospheric formation during the nebular phase and the following few million years. ARIEL will thus provide a representative picture of the chemical nature of the exoplanets and relate this directly to the type and chemical environment of the host star. ARIEL is designed as a dedicated survey mission for combined-light spectroscopy, capable of observing a large and well-defined planet sample within its 4-year mission lifetime. Transit, eclipse and phase-curve spectroscopy methods, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allow us to measure atmospheric signals from the planet at levels of 10–100 part per million (ppm) relative to the star and, given the bright nature of targets, also allows more sophisticated techniques, such as eclipse mapping, to give a deeper insight into the nature of the atmosphere. These types of observations require a stable payload and satellite platform with broad, instantaneous wavelength coverage to detect many molecular species, probe the thermal structure, identify clouds and monitor the stellar activity. The wavelength range proposed covers all the expected major atmospheric gases from e.g. H2O, CO2, CH4 NH3, HCN, H2S through to the more exotic metallic compounds, such as TiO, VO, and condensed species. Simulations of ARIEL performance in conducting exoplanet surveys have been performed – using conservative estimates of mission performance and a full model of all significant noise sources in the measurement – using a list of potential ARIEL targets that incorporates the latest available exoplanet statistics. The conclusion at the end of the Phase A study, is that ARIEL – in line with the stated mission objectives – will be able to observe about 1000 exoplanets depending on the details of the adopted survey strategy, thus confirming the feasibility of the main science objectives.Peer reviewedFinal Published versio

    Occupied refugee

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    É crescente nos noticiários a quantidade de informações sobre os refugiados. As mídias cedem cada vez mais espaço àquilo que chamam, na Europa, de crise migratória” e, no caso brasileiro, de “invasão de haitianos”, posterior ao terremoto que devastou o país caribenho. Nas ruas de diversas metrópoles, do Brasil e do mundo, conhecidas por seu caráter cosmopolita, surgem outras línguas, cores, estampas e sabores, e frequentemente temos a impressão de nunca ter visto tantas culturas em um mesmo lugar. O tema tem se tornado objeto de reflexão não apenas na imprensa, mas também nos debates antropológicos. Embora os grandes deslocamentos e as diásporas, causados muitas vezes por motivos como a guerra, a fome ou a perseguição político-religiosa, não sejam assuntos tão novos para a disciplina, as características que vêm adquirindo nos últimos anos desdobram-se em novas problematizações e abordagens que justificam o espaço dedicado ao tema neste número da Cadernos de Campo

    Closing ranks, learning from those who struggle: reflections on rights in contemporary Brazil

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    O ano de 2016 custou a passar. Enquanto a nossa revista celebrava 25 anos de sua criação, o Brasil testemunhava um dos momentos mais dramáticos da história de sua jovem democracia. Em abril, assistíamos à votação do impeachment da primeira mulher a ocupar o mais alto cargo executivo do país, a presidenta Dilma Rousseff, na Câmara dos Deputados. Citações a torturadores dos tempos da ditadura, elogio ao Golpe de 1964, incontáveis menções à família e louvações a Deus como justificativas de voto tornavam evidente que o centro da peça jurídica, as chamadas “pedaladas fiscais”, não estava entre os problemas mais graves da atual crise política. Dois dias depois, Michel Temer assumia a presidência interinamente, até que, em agosto, os senadores consumaram um processo de impeachment de questionável base jurídica e ele pôde, então, tornar- -se o novo presidente da República

    RNAcentral 2021: secondary structure integration, improved sequence search and new member databases

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    RNAcentral is a comprehensive database of non-coding RNA (ncRNA) sequences that provides a single access point to 44 RNA resources and >18 million ncRNA sequences from a wide range of organisms and RNA types. RNAcentral now also includes secondary (2D) structure information for >13 million sequences, making RNAcentral the world's largest RNA 2D structure database. The 2D diagrams are displayed using R2DT, a new 2D structure visualization method that uses consistent, reproducible and recognizable layouts for related RNAs. The sequence similarity search has been updated with a faster interface featuring facets for filtering search results by RNA type, organism, source database or any keyword. This sequence search tool is available as a reusable web component, and has been integrated into several RNAcentral member databases, including Rfam, miRBase and snoDB. To allow for a more fine-grained assignment of RNA types and subtypes, all RNAcentral sequences have been annotated with Sequence Ontology terms. The RNAcentral database continues to grow and provide a central data resource for the RNA community

    RNAcentral 2021: secondary structure integration, improved sequence search and new member databases.

    Get PDF
    RNAcentral is a comprehensive database of non-coding RNA (ncRNA) sequences that provides a single access point to 44 RNA resources and >18 million ncRNA sequences from a wide range of organisms and RNA types. RNAcentral now also includes secondary (2D) structure information for >13 million sequences, making RNAcentral the world's largest RNA 2D structure database. The 2D diagrams are displayed using R2DT, a new 2D structure visualization method that uses consistent, reproducible and recognizable layouts for related RNAs. The sequence similarity search has been updated with a faster interface featuring facets for filtering search results by RNA type, organism, source database or any keyword. This sequence search tool is available as a reusable web component, and has been integrated into several RNAcentral member databases, including Rfam, miRBase and snoDB. To allow for a more fine-grained assignment of RNA types and subtypes, all RNAcentral sequences have been annotated with Sequence Ontology terms. The RNAcentral database continues to grow and provide a central data resource for the RNA community. RNAcentral is freely available at https://rnacentral.org
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