88 research outputs found

    Incoherent Interplane Conductivity of kappa-(BEDT-TTF)2Cu[N(CN)2]Br

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    The interplane optical spectrum of the organic superconductor kappa-(BEDT-TTF)2Cu[N(CN)2]Br was investigated in the frequency range from 40 to 40,000 cm-1. The optical conductivity was obtained by Kramers-Kronig analysis of the reflectance. The absence of a Drude peak at low frequency is consistent with incoherent conductivity but in apparent contradiction to the metallic temperature dependence of the DC resistivity. We set an upper limit to the interplane transfer integral of tb = 0.1 meV. A model of defect-assisted interplane transport can account for this discrepancy. We also assign the phonon lines in the conductivity to the asymmetric modes of the ET molecule.Comment: 7 pages with embedded figures, submitted to PR

    Consistency of FDG-PET Accuracy and Cost-Effectiveness in Initial Staging of Patients With Hodgkin Lymphoma Across Jurisdictions.

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    INTRODUCTION: Two hundred ten patients with newly diagnosed Hodgkin's lymphoma (HL) were consecutively enrolled in this prospective trial to evaluate the cost-effectiveness of fluorine-18 ((18)F)-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) scan in initial staging of patients with HL. METHODS: All 210 patients were staged with conventional clinical staging (CCS) methods, including computed tomography (CT), bone marrow biopsy (BMB), and laboratory tests. Patients were also submitted to metabolic staging (MS) with whole-body FDG-PET scan before the beginning of treatment. A standard of reference for staging was determined with all staging procedures, histologic examination, and follow-up examinations. The accuracy of the CCS was compared with the MS. Local unit costs of procedures and tests were evaluated. Incremental cost-effectiveness ratio (ICER) was calculated for both strategies. RESULTS: In the 210 patients with HL, the sensitivity for initial staging of FDG-PET was higher than that of CT and BMB in initial staging (97.9% vs. 87.3%; P < .001 and 94.2% vs. 71.4%, P < 0.003, respectively). The incorporation of FDG-PET in the staging procedure upstaged disease in 50 (24%) patients and downstaged disease in 17 (8%) patients. Changes in treatment would be seen in 32 (15%) patients. Cumulative cost for staging procedures was 3751/patientforCCScomparedto3751/patient for CCS compared to 5081 for CCS + PET and 4588forPET/CT.TheICERofPET/CTstrategywas4588 for PET/CT. The ICER of PET/CT strategy was 16,215 per patient with modified treatment. PET/CT costs at the beginning and end of treatment would increase total costs of HL staging and first-line treatment by only 2%. CONCLUSION: FDG-PET is more accurate than CT and BMB in HL staging. Given observed probabilities, FDG-PET is highly cost-effective in the public health care program in Brazil

    Fontes alternativas à ureia no fornecimento de nitrogênio para o arroz irrigado Alternative sources of supply in the urea nitrogen for rice production

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    A ureia é a principal fonte de N usada na agricultura, mas apresenta grandes perdas em arroz irrigado por alagamento. O objetivo deste trabalho foi avaliar a eficiência de fontes de N alternativas à ureia para utilização pelo arroz irrigado aplicadas em diferentes estádios de desenvolvimento da planta através da quantificação da volatilização de N-NH3 e de parâmetros agronômicos. O experimento foi realizado em campo nos anos agrícolas 2007/08 e 2008/09. O delineamento experimental foi de blocos ao acaso com quatro repetições. Os tratamentos foram compostos de diferentes fontes de N aplicados na semeadura, no perfilhamento e no estádio de diferenciação floral: testemunha sem aplicação de N, ureia, ureia+inibidor de urease, duas fontes de N líquido (N-28 e N- 30), sulfato de amônio e ureia + enxofre. Nas duas safras, a volatilização de N-NH3 na semeadura foi praticamente insignificante, enquanto no estádio V4 a fonte que menos volatilizou foi o sulfato de amônio. A resposta em produtividade variou entre os anos, provavelmente em função da disponibilidade de N no solo e aspectos climáticos. Quando vantajoso economicamente, o uso do inibidor de urease e o sulfato de amônio proporcionam produtividades semelhantes à fonte ureia.<br>Urea is the main source of N used in agriculture, but has large losses in irrigated rice. The objective of this study was to evaluate the efficiency of N sources alternative to urea for use by rice applied at different stages of plant development through the quantification of N-NH3 and agronomic parameters. The experiment was conducted in the field in the agricultural years 2007/08 and 2008/09. The experimental design was randomized blocks with four replications. The treatments consisted of different N sources applied at seeding, tillering and at the stage of floral differentiation: control without N, urea, urea + urease inhibitor, two sources of liquid N (N-28 and N-30) ammonium sulfate and urea + sulfur. In both seasons, the volatilization of N-NH3 at seeding was almost negligible, whereas in the V4 stage, the source that was less volatilized was the ammonium sulfate. Yield response varied among years, probably due to the availability of N in the soil and climatic aspects. When economically advantageous, the use of urease inhibitor and ammonium sulfate provide yields similar to urea supply
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