41 research outputs found

    Book Reviews

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    Reviews of the following books: A History of Lumbering in Maine: 1861-1960 by David C. Smith; Edward Preble: A Naval Biography: 1761-1807 by Christopher McKee; New England and the Sea by Robert G. Albion, William A. Baker, Benjamin W. Larabee and Marion V. Brewington; Naval and Maritime History: An Annotated Bibliography by Robert G. Albio

    Kepler-21b: A 1.6REarth Planet Transiting the Bright Oscillating F Subgiant Star HD 179070

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    We present Kepler observations of the bright (V=8.3), oscillating star HD 179070. The observations show transit-like events which reveal that the star is orbited every 2.8 days by a small, 1.6 R_Earth object. Seismic studies of HD 179070 using short cadence Kepler observations show that HD 179070 has a frequencypower spectrum consistent with solar-like oscillations that are acoustic p-modes. Asteroseismic analysis provides robust values for the mass and radius of HD 179070, 1.34{\pm}0.06 M{\circ} and 1.86{\pm}0.04 R{\circ} respectively, as well as yielding an age of 2.84{\pm}0.34 Gyr for this F5 subgiant. Together with ground-based follow-up observations, analysis of the Kepler light curves and image data, and blend scenario models, we conservatively show at the >99.7% confidence level (3{\sigma}) that the transit event is caused by a 1.64{\pm}0.04 R_Earth exoplanet in a 2.785755{\pm}0.000032 day orbit. The exoplanet is only 0.04 AU away from the star and our spectroscopic observations provide an upper limit to its mass of ~10 M_Earth (2-{\sigma}). HD 179070 is the brightest exoplanet host star yet discovered by Kepler.Comment: Accepted to Ap

    Kepler Planet-Detection Mission: Introduction and First Results

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    The Kepler mission was designed to determine the frequency of Earth-sized planets in and near the habitable zone of Sun-like stars. The habitable zone is the region where planetary temperatures are suitable for water to exist on a planet’s surface. During the first 6 weeks of observations, Kepler monitored 156,000 stars, and five new exoplanets with sizes between 0.37 and 1.6 Jupiter radii and orbital periods from 3.2 to 4.9 days were discovered. The density of the Neptune-sized Kepler-4b is similar to that of Neptune and GJ 436b, even though the irradiation level is 800,000 times higher. Kepler-7b is one of the lowest-density planets (~0.17 gram per cubic centimeter) yet detected. Kepler-5b, -6b, and -8b confirm the existence of planets with densities lower than those predicted for gas giant planets

    Perspectives in Global Helioseismology, and the Road Ahead

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    We review the impact of global helioseismology on key questions concerning the internal structure and dynamics of the Sun, and consider the exciting challenges the field faces as it enters a fourth decade of science exploitation. We do so with an eye on the past, looking at the perspectives global helioseismology offered in its earlier phases, in particular the mid-to-late 1970s and the 1980s. We look at how modern, higher-quality, longer datasets coupled with new developments in analysis, have altered, refined, and changed some of those perspectives, and opened others that were not previously available for study. We finish by discussing outstanding challenges and questions for the field.Comment: Invited review; to appear in Solar Physics (24 pages, 6 figures

    A História da Alimentação: balizas historiográficas

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    Os M. pretenderam traçar um quadro da História da Alimentação, não como um novo ramo epistemológico da disciplina, mas como um campo em desenvolvimento de práticas e atividades especializadas, incluindo pesquisa, formação, publicações, associações, encontros acadêmicos, etc. Um breve relato das condições em que tal campo se assentou faz-se preceder de um panorama dos estudos de alimentação e temas correia tos, em geral, segundo cinco abardagens Ia biológica, a econômica, a social, a cultural e a filosófica!, assim como da identificação das contribuições mais relevantes da Antropologia, Arqueologia, Sociologia e Geografia. A fim de comentar a multiforme e volumosa bibliografia histórica, foi ela organizada segundo critérios morfológicos. A seguir, alguns tópicos importantes mereceram tratamento à parte: a fome, o alimento e o domínio religioso, as descobertas européias e a difusão mundial de alimentos, gosto e gastronomia. O artigo se encerra com um rápido balanço crítico da historiografia brasileira sobre o tema

    Flue-Cured Tobacco Mechanization and Labor: Impacts of Alternative Production Levels

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    The flue-cured tobacco industry is in a state of transition as farmers are replacing the traditional harvest methods with modern bulk curing systems. The rapid trend toward harvest mechanization experienced in 1972-75 will continue into the eighties, according to an analysis of a wide range of quota levels and wage rates. Adopting new harvest technology is profitable for farmers, and it will have an impact on the demand for harvest labor. In the aggregate, however, harvest mechanization will not cause serious unemployment problems in the flue-cured tobacco belt. During 1972-80, with increased wage rates, the decline in the number of harvest workers is projected to range from 64,000 workers, under a "high" level of production, to 199,000, under a "low" level of production. Harvest jobs are part-time and seasonal. Workers most likely to lose harvest job opportunities are young persons and women. Of tasks eliminated with bulk curing systems, more than 90 percent in 1972 were performed by young persons (mainly 12 to 15 years of age) and by women

    Structural Characteristics of Flue-Cured Tobacco Farms and Prospects for Harvest Mechanization

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    By 1978, mechanical harvesters will be used to harvest an estimated 23-36 percent of the flue-cured tobacco acreage in the study area, which produces three-fourths of all U.S. flue-cured tobacco. Farmers will use bulk barns to cure an expected 65-80 percent of it. Comparison figures of 1972 are 1 and 8 percent, respectively. If these changes occur, labor needed during the harvest will fall as much as 50 percent between 1972 and 1978. In 1972, flue-cured tobacco management units averaged 9.5 acres in the study area, or about three times the size of the average flue-cured tobacco allotment. Close to 60 percent of these units use some harvest system that differs from the more traditional methods: • 8 percent — bulk barns • 47 percent — machines to tie tobacco leaves on sticks • 30 percent — priming aids • 20 percent — traditional method

    The susceptibility of Atlantic salmon fry to freshwater infectious pancreatic necrosis is largely explained by a major QTL

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    Infectious pancreatic necrosis (IPN) is a viral disease with a significant negative impact on the global aquaculture of Atlantic salmon. IPN outbreaks can occur during specific windows of both the freshwater and seawater stages of the salmon life cycle. Previous research has shown that a proportion of the variation seen in resistance to IPN is because of host genetics, and we have shown that major quantitative trait loci (QTL) affect IPN resistance at the seawater stage of production. In the current study, we completed a large freshwater IPN challenge experiment to allow us to undertake a thorough investigation of the genetic basis of resistance to IPN in salmon fry, with a focus on previously identified QTL regions. The heritability of freshwater IPN resistance was estimated to be 0.26 on the observed scale and 0.55 on the underlying scale. Our results suggest that a single QTL on linkage group 21 explains almost all the genetic variation in IPN mortality under our experimental conditions. A striking contrast in mortality is seen between fry classified as homozygous susceptible versus homozygous resistant, with QTL-resistant fish showing virtually complete resistance to IPN mortality. The findings highlight the importance of the major QTL in the genetic regulation of IPN resistance across distinct physiological lifecycle stages, environmental conditions and viral isolates. These results have clear scientific and practical implications for the control of IPN
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