294 research outputs found
Consórcios de caupi e milho em cultivo orgùnico para produção de grãos e espigas verdes.
No perĂodo de outono-inverno-primavera de 2007, foi conduzido um estudo em SeropĂ©dica, RegiĂŁo Metropolitana do estado do Rio de Janeiro (Baixada Fluminense), com o objetivo de avaliar diferentes tipos de consĂłrcio entre caupi (cv. MauĂĄ) e milho (cv. AG-1051), em sistema orgĂąnico de produção. O experimento foi instalado em ĂĄrea de Argissolo Vermelho-Amarelo no delineamento de blocos ao acaso, com quatro repetiçÔes. Os tratamentos constaram de diferentes Ă©pocas ou intervalos de tempo de semeadura do caupi em relação Ă do milho, a saber: (E1) 21 dias antes do milho; (E2) 14 dias antes do milho; (E3) 7 dias antes do milho; e (E4) no mesmo dia do milho. Tratamentos correspondentes aos cultivos solteiros do caupi e do milho foram incluĂdos, ambos semeados na data do tratamento E4. O cultivo consorciado com o caupi nĂŁo interferiu na produtividade do milho em espigas verdes e tambĂ©m em termos de comprimento e diĂąmetro basal dessas espigas, independentemente do intervalo entre semeaduras. Com referĂȘncia ao caupi, a produtividade em grĂŁos verdes no cultivo solteiro foi superior Ă dos consĂłrcios com o milho. Os valores obtidos para os Ăndices de EquivalĂȘncia de Ărea (IEA), foram todos acima de 1,0, indicando que os consĂłrcios foram eficientes quanto ao desempenho agronĂŽmico/biolĂłgico. Considerando, ainda a produtividade de cada cultura participante do consĂłrcio, a semeadura do caupi antecipada de 21 dias em relação Ă do milho afigura-se mais adequada ao manejo orgĂąnico adotado e Ă s condiçÔes edafoclimĂĄticas da regiĂŁo
Multi-messenger observations of a binary neutron star merger
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 transientâs 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
Genesis and Classification of Soils Containing Carbonates in a Toposequence of the BambuĂ Group
Chemical-Mineralogical Characterization of Magnetic Materials from Magnetic Soils of the Southern Espinhaço Mountain Chain and of the Upper Jequitinhonha Valley, State of Minas Gerais, Brazil
Morphological Diversity of Coleoptera (Arthropoda: Insecta) in Agriculture and Forest Systems
Leishmania amazonensis DNA in wild females ofLutzomyia cruzi (Diptera: Psychodidae) in the state of Mato Grosso do Sul, Brazil
A comparison of rural educational disadvantage in Australia, Canada, and New Zealand using OECDâs PISA
This study compares rural educational disadvantage across Australia, Canada, and New Zealand using data from the Organisation for Economic Co-operation and Developmentâs Programme for International Student Assessment (PISA). Across the three countries, student reading literacy and school learning environments are less positive in rural communities than in urban. Furthermore, rural disadvantage in educational outcomes (reading) and opportunities is greater in Australia than Canada or New Zealand. This could be seen as surprising as student socioeconomic status (SES), typically a strong predictor of educational outcomes, is similar for rural communities in Australia and Canada, but lower in New Zealand. Rural school principals in Australia are most likely among the three countries to report that shortages of teaching personnel hinder learning. This could suggest that policies and structures can play a role in ameliorating or exacerbating rural educational disadvantage. We conclude with questions and recommendations for future research
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