Avaliação de linhagens promissoras de aveia para produção de grãos e forragem em São Carlos, SP, Brasil.

Foram testadas 13 linhagens de aveias provenientes da Universidade de Passo Fundo, RS, foram testadas quanto a sua capacidade de produção de forragem e grãos, pela EMBRAPA-UEPAE, São Carlos, SP.bitstream/item/120269/1/digitalizar0018.pdfPesquisa em Andamento

Avaliação preliminar de germoplasma de aveia.

Foram avaliados pela EMBRAPA-UEPAE, São Carlos, SP, 50 genotipos, com o objetivo de selecionar germoplasma para o desenvolvimento de novas linhagens de aveia.bitstream/item/120275/1/digitalizar0021.pdfPesquisa em Andamento

Ensaio nacional de aveias forrageiras, 1997: analise conjunta.

Resumo

Ensaio nacional de aveias forrageiras, 1997: análise conjunta.

Com o objetivo de avaliar genotipos de aveias (brancas e pretas), nos diferentes ambientes do Sul do Brasil, para aptidao forrageira, conduziu-se um ensaio em rede em 13 locais (4 no Rio Grande do Sul, 3 em Santa Catarina, 5 no Parana e 1 em Sao Paulo)

Ensaio nacional de aveias forrageiras, 1997: análise conjunta.

Planta forrageira, Aveia, Ensaio nacional; Forage; Oat; Essay.Resumo

Multiple generations of grain aggregation in different environments preceded solar system body formation

Manuscript submitted to Proceedings of the National Academy of ScienceThe solar system formed from interstellar dust and gas in a molecular cloud. Astronomical observations show that typical interstellar dust consists of amorphous (a-) silicate and organic carbon. Bona fide physical samples for laboratory studies would yield unprecedented insight about solar system formation, but they were largely destroyed. The most likely repositories of surviving presolar dust are the least altered extraterrestrial materials, interplanetary dust particles (IDPs) with probable cometary origins. Cometary IDPs contain abundant submicron a-silicate grains called GEMS, believed to be carbon-free. Some have detectable isotopically anomalous a-silicate components from other stars, proving they are preserved dust inherited from the interstellar medium. However, it is debated whether the majority of GEMS predate the solar system or formed in the solar nebula by condensation of high-temperature (>1300K) gas. Here, we map IDP compositions with single nanometer-scale resolution and find that GEMS contain organic carbon. Mapping reveals two generations of grain aggregation, the key process in growth from dust grains to planetesimals, mediated by carbon. GEMS grains, some with a-silicate subgrains mantled by organic carbon, comprise the earliest generation of aggregates. These aggregates (and other grains) are encapsulated in lower density organic carbon matrix, indicating a second generation of aggregation. Since this organic carbon thermally decomposes above ~450K, GEMS cannot have accreted in the hot solar nebula and formed, instead, in the cold presolar molecular cloud and/or outer protoplanetary disk. We suggest that GEMS are consistent with surviving interstellar dust, condensed in situ, and cycled through multiple molecular clouds.Portions of this work were performed at the Molecular Foundry and the Advanced Light Source at Lawrence Berkeley National Laboratory, which are supported by the Office of Science, Basic Energy Sciences, U.S. Department of Energy under Contract No. DE-AC02-05CH11231. HAI acknowledges funding by NASA’s Laboratory Analysis of Returned Samples and Emerging Worlds Programs (NNX14AH86G and NNX16AK41G). JPB acknowledges funding by NASA’s Cosmochemistry Program (NNX14AI39G). CF acknowledges funding by NASA’s Cosmochemistry Program (NNX14AG25G)

Non-Random Spatial Distribution of Impacts in the Stardust Cometary Collector

In January 2004, the Stardust spacecraft flew through the coma of comet P81/Wild2 at a relative speed of 6.1 km/sec. Cometary dust was collected at in a 0.1 sq m collector consisting of aerogel tiles and aluminum foils. Two years later, the samples successfully returned to earth and were recovered. We report the discovery that impacts in the Stardust cometary collector are not distributed randomly in the collecting media, but appear to be clustered on scales smaller than approx.10 cm. We also report the discovery of at least two populations of oblique tracks. We evaluated several hypotheses that could explain the observations. No hypothesis was consistent with all the observations, but the preponderance of evidence points toward at least one impact on the central Whipple shield of the spacecraft as the origin of both clustering and low-angle oblique tracks. High-angle oblique tracks unambiguously originate from a noncometary impact on the spacecraft bus just forward of the collector. Here we summarize the observations, and review the evidence for and against three scenarios that we have considered for explaining the impact clustering found on the Stardust aerogel and foil collectors