5,969 research outputs found

    The subcritical baroclinic instability in local accretion disc models

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    (abridged) Aims: We present new results exhibiting a subcritical baroclinic instability (SBI) in local shearing box models. We describe the 2D and 3D behaviour of this instability using numerical simulations and we present a simple analytical model describing the underlying physical process. Results: A subcritical baroclinic instability is observed in flows stable for the Solberg-Hoiland criterion using local simulations. This instability is found to be a nonlinear (or subcritical) instability, which cannot be described by ordinary linear approaches. It requires a radial entropy gradient weakly unstable for the Schwartzchild criterion and a strong thermal diffusivity (or equivalently a short cooling time). In compressible simulations, the instability produces density waves which transport angular momentum outward with typically alpha<3e-3, the exact value depending on the background temperature profile. Finally, the instability survives in 3D, vortex cores becoming turbulent due to parametric instabilities. Conclusions: The subcritical baroclinic instability is a robust phenomenon, which can be captured using local simulations. The instability survives in 3D thanks to a balance between the 2D SBI and 3D parametric instabilities. Finally, this instability can lead to a weak outward transport of angular momentum, due to the generation of density waves by the vortices.Comment: 12 pages, 17 figures, Accepted in A&

    Minimalist AdaBoost for blemish identification in potatoes

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    We present a multi-class solution based on minimalist Ad- aBoost for identifying blemishes present in visual images of potatoes. Using training examples we use Real AdaBoost to rst reduce the fea- ture set by selecting ve features for each class, then train binary clas- siers for each class, classifying each testing example according to the binary classier with the highest certainty. Against hand-drawn ground truth data we achieve a pixel match of 83% accuracy in white potatoes and 82% in red potatoes. For the task of identifying which blemishes are present in each potato within typical industry dened criteria (10% coverage) we achieve accuracy rates of 93% and 94%, respectively

    Distribuição espacial das necessidades hídricas das culturas do feijão, milho e soja na bacia do rio Tibaji, PR.

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    Yield simulation for maize production maximization in the State of Goiás, Brazil, by using the Ceres-Maize model.

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    The aim of this study was to determine the best cultivar and sowing date to be use for maize in state of Goiás, to maximize the maize grain yield. It was used the Cropping System Model (CSM)-CERES-Maize, part of the DSSAT (Decision Support System for Agrotechnology Transfer) for yield simulation of two cultivars (DAS CO32 and DKB 333B) for seven sowing dates (01/11, 10/11, 20/11, 01/12, 10/12, 20/12 and 30/12), for eight locations in the state of Goiás. The meteorological data were obtained from SECTEC/SIMEHGO weather stations, for periods ranging from 5 to 27 years. The decision criteria used were the yield variability between the sowing dates, comparison of exceedance probability for yield and percentage of yield reduction due to water deficiency. The results showed that the highest simulated yield for the state of Goiás was obtained for DAS CO32 cultivar, for the sowing date of 10/12. This sowing date also showed the lowest percentage of yield reduction

    Prospective Multicenter Randomized Phase III Study of Weekly versus Standard Docetaxel plus Doxorubicin (D4) for First-Line Treatment of Metastatic Breast Cancer

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    Purpose: Previous phase II studies have indicated a greatly reduced hematotoxicity of docetaxel-based regimens administered on weekly schedules. The present trial was initiated to compare the toxicity and efficacy of weekly docetaxel versus its standard 3-weekly application in combination with doxorubicin. Methods: Patients previously untreated with chemotherapy for metastatic disease were recruited. Inclusion criteria were age = grade 3 was observed in the standard arm of the D4 study compared to the weekly schedule (per-patient analysis: 61.9% q3w vs. 65.1% q1w; p > 0.05). Grade 3 and grade 4 fever, diarrhea, and infections occurred more frequently in the standard arm, whereas neurotoxicity and skin/nail disorders were observed more frequently in the weekly arm. Except for fever, none of these differences reached a level of significance. Dose delays, dose reductions, and the rate of omitted doses were increased in the weekly arm. The overall response rate was 44.2% in the weekly arm compared to 52.4% in the standard arm (p = 0.52). Time to progression was 6.2 (q1w) versus 10.3 (q3w) months (p = 0.36), and overall survival was 20.5 (q1w) versus 28.7 (q3w) months (p = 0.98). Conclusion: The present data support the feasibility of both weekly and 3-weekly application of docetaxel in combination with doxorubicin. Nevertheless, given that leukopenia was similar in both arms and the efficacy parameters were at least numerically inferior with the weekly schedule, standard 3-weekly application seems to be preferable for patients requiring combination chemotherapy. Copyright (C) 2011 S. Karger AG, Base

    Prospective Multicenter Randomized Phase III Study of Weekly versus Standard Docetaxel (D2) for First-Line Treatment of Metastatic Breast Cancer

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    Purpose: Previous phase II studies have indicated a greatly reduced hematotoxicity of docetaxel-based regimens administered on weekly schedules. The present trial was initiated to randomly compare the toxicity and efficacy of weekly docetaxel versus its standard 3-weekly application. Methods: Patients previously untreated with chemotherapy for metastatic disease were recruited. Patients aged >60 years or with a Karnofsky Perfomance Status (KPS) of 60-80% were eligible for the D2 study. Patients were randomized to receive docetaxel either on a 3-weekly {[}75 mg/m(2) every 3 weeks (q3w)] or on a weekly (30 mg/m(2) on days 1, 8, and 15; q4w) schedule. Treatment was continued until a maximum of 8 cycles, unacceptable toxicity, or disease progression. All patients received standard corticosteroid prophylaxis. Results: Since statistical significance for the primary endpoint (toxicity) was achieved in the interim analysis, the study was closed according to the study protocol (102 of 162 patients). Compared to the standard arm, leukopenia >= grade 3 was a rare event in the weekly arm of the D2 study (per-patient analysis: 4.2% q1w vs. 51.9% q3w; p < 0.0001). No difference was observed between the 2 schedules regarding the occurrence of anemia or thrombocytopenia. With regard to non-hematological toxicity, there was a higher incidence of skin/nail and hepatological toxicity with the weekly schedule, whereas neurotoxicity was observed more often in the standard arm. The rate of omitted doses was significantly increased in the weekly arm (8.6% q1w vs. 0% q3w). The overall response rate was 22.9% in the weekly arm compared to 42.6% in the standard arm (p = 0.039). Time to progression was 5.4 (q1w) versus 6.3 (q3w) months (p = 0.91), and overall survival was 22.7 (q1w) versus 15.8 (q3w) months (p = 0.24). Conclusion: The present data support the feasibility of both weekly and 3-weekly application of docetaxel. As expected, severe leukopenia seems avoidable in weekly scheduled single-agent docetaxel and may serve as an important treatment option, particularly in elderly patients and patients with a reduced performance status. Copyright (C) 2011 S. Karger AG, Base

    Caracteres morfológicos do crescimento e desenvolvimento de quatro cultivares de arroz de terras altas.

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    Esse estudo teve como objetivo identificar e comparar os principais processos morfológicos relacionados ao desenvolvimento e crescimento de quatro diferentes cultivares de arroz de terras altas na fase vegetativa.bitstream/CNPAF-2009-09/27968/1/doc_229.pd

    Panorama ambiental e fisio-molecular do arroz de terras altas.

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    Nessa revisão são descritos os diferentes ambientes na região produtora do arroz de terras altas no Brasil, os principais impactos que a planta de arroz de terras altas enfrenta em condições de deficiência hídrica e as perspectivas para mitigação dos efeitos desse tipo de estresse.bitstream/item/60714/1/seriedocumentos-274.pd
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