2,304 research outputs found

    Fish seed production in ricefields: participatory training and extension manual

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    Seed (aquaculture), Rice field aquaculture, Rice fields, Manuals Oreochromis niloticus

    Direct Imaging of Multiple Planets Orbiting the Star HR 8799

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    Direct imaging of exoplanetary systems is a powerful technique that can reveal Jupiter-like planets in wide orbits, can enable detailed characterization of planetary atmospheres, and is a key step towards imaging Earth-like planets. Imaging detections are challenging due to the combined effect of small angular separation and large luminosity contrast between a planet and its host star. High-contrast observations with the Keck and Gemini telescopes have revealed three planets orbiting the star HR 8799, with projected separations of 24, 38, and 68 astronomical units. Multi-epoch data show counter-clockwise orbital motion for all three imaged planets. The low luminosity of the companions and the estimated age of the system imply planetary masses between 5 and 13 times that of Jupiter. This system resembles a scaled-up version of the outer portion of our Solar System.Comment: 30 pages, 5 figures, Research Article published online in Science Express Nov 13th, 200

    Astrometric Monitoring of the HR 8799 Planets: Orbit Constraints from Self-Consistent Measurements

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    We present new astrometric measurements from our ongoing monitoring campaign of the HR 8799 directly imaged planetary system. These new data points were obtained with NIRC2 on the W.M. Keck II 10 meter telescope between 2009 and 2014. In addition, we present updated astrometry from previously published observations in 2007 and 2008. All data were reduced using the SOSIE algorithm, which accounts for systematic biases present in previously published observations. This allows us to construct a self-consistent data set derived entirely from NIRC2 data alone. From this dataset, we detect acceleration for two of the planets (HR 8799b and e) at >>3σ\sigma. We also assess possible orbital parameters for each of the four planets independently. We find no statistically significant difference in the allowed inclinations of the planets. Fitting the astrometry while forcing coplanarity also returns χ2\chi^2 consistent to within 1σ\sigma of the best fit values, suggesting that if inclination offsets of \lesssim20o^{o} are present, they are not detectable with current data. Our orbital fits also favor low eccentricities, consistent with predictions from dynamical modeling. We also find period distributions consistent to within 1σ\sigma with a 1:2:4:8 resonance between all planets. This analysis demonstrates the importance of minimizing astrometric systematics when fitting for solutions to highly undersampled orbits.Comment: 18 pages, 11 figures. Accepted for publication in A

    Acute aortic dissection in a young healthy athlete with androgenic anabolic steroid use: A case report

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    Background: Acute aortic dissection can occur at the time of intense physical exertion in strength-trained athletes like weight lifters, bodybuilders, throwers, and wrestlers. Rapid rise in blood pressure and history of hypertension are the most common causes of aortic dissection in athletes. It is a very tragic event because of its high mortality rate of about 32% in young patients. We report a case of aortic dissection in a young weightlifter with a history of anabolic steroid usage with an extensive intimal tear of the aorta at Sino tubular junction and arch. All athletes must be assessed for predisposing factors for aortic dissection, and all patients should be encouraged to undergo appropriate diagnostic studies, like echocardiography and blood pressure monitoring while weightlifting to recognize possible predisposing factors for aortic dissection. Athletes who do have a problem should be encouraged to avoid or limit their exercise or activity by their cardiologist. It is vital that this disastrous event be prevented in young people. In conclusion, although a rare occurrence, AD should be considered in symptomatic patients with any family history of early cardiac deaths, a history suggestive of a connective tissue disorder (that is, multiple joint surgeries) or who practice weightlifting

    Rice blast fungus sequenced

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    Generation of High Spatial Resolution Terrestrial Surface from Low Spatial Resolution Elevation Contour Maps via Hierarchical Computation of Median Elevation Regions

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    We proposed a simple yet effective morphological approach to convert a sparse Digital Elevation Model (DEM) to a dense Digital Elevation Model. The conversion is similar to that of the generation of high-resolution DEM from its low-resolution DEM. The approach involves the generation of median contours to achieve the purpose. It is a sequential step of the I) decomposition of the existing sparse Contour map into the maximum possible Threshold Elevation Region (TERs). II) Computing all possible non-negative and non-weighted Median Elevation Region (MER) hierarchically between the successive TER decomposed from a sparse contour map. III) Computing the gradient of all TER, and MER computed from previous steps would yield the predicted intermediate elevation contour at a higher spatial resolution. We presented this approach initially with some self-made synthetic data to show how the contour prediction works and then experimented with the available contour map of Washington, NH to justify its usefulness. This approach considers the geometric information of existing contours and interpolates the elevation contour at a new spatial region of a topographic surface until no elevation contours are necessary to generate. This novel approach is also very low-cost and robust as it uses elevation contours.Comment: 11 pages, 6 figures,1 table, 1 algorith

    Phase-Dependent Properties of Extrasolar Planet Atmospheres

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    Recently the Spitzer Space Telescope observed the transiting extrasolar planets, TrES-1 and HD209458b. These observations have provided the first estimates of the day side thermal flux from two extrasolar planets orbiting Sun-like stars. In this paper, synthetic spectra from atmospheric models are compared to these observations. The day-night temperature difference is explored and phase-dependent flux densities are predicted for both planets. For HD209458b and TrES-1, models with significant day-to-night energy redistribution are required to reproduce the observations. However, the observational error bars are large and a range of models remains viable.Comment: 8 pages, 7 figures, accepted for publication in the Astrophysical Journa

    Accurate Spitzer infrared radius measurement for the hot Neptune GJ 436b

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    We present Spitzer Space Telescope infrared photometry of a primary transit of the hot Neptune GJ 436b. The observations were obtained using the 8 microns band of the InfraRed Array Camera (IRAC). The high accuracy of the transit data and the weak limb-darkening in the 8 microns IRAC band allow us to derive (assuming M = 0.44 +- 0.04 Msun for the primary) a precise value for the planetary radius (4.19 +0.21-0.16 Rearth), the stellar radius (0.463 +0.022-0.017 Rsun), the orbital inclination (85.90 +0.19-0.18 degrees) and transit timing (2454280.78186 +0.00015-0.00008 HJD). Assuming current planet models, an internal structure similar to that of Neptune with a small H/He envelope is necessary to account for the measured radius of GJ 436b.Comment: Accepted for publication in A&A on 21/07/2007; 5 pages, 3 figure
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