6,199 research outputs found

    Quark core formation in spinning-down pulsars

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    Pulsars spin-down due to magnetic torque reducing its radius and increasing the central energy density. Some pulsar which are born with central densities close to the critical value of quark deconfinement may undergo a phase transition and structural re-arrengement. This process may excite oscillation modes and emmit gravitational waves. We determine the rate of quark core formation in neutron stars using a realistic population synthesis code.Comment: Proceedings of the 2nd International Workshop on Astronomy and Relativistic Astrophysics, to appear in IJMP

    Expected Coalescence Rate of Double Neutron Stars for Ground Based Interferometers

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    In this paper we present new estimates of the coalescence rate of neutron star binaries in the local universe and we discuss its consequences for the first generations of ground based interferometers. Our approach based on both evolutionary and statistical methods gives a galactic merging rate of 1.7 105^{-5} yr1^{-1}, in the range of previous estimates 106^{-6} - 104^{-4} yr1^{-1}. The local rate which includes the contribution of elliptical galaxies is two times higher, in the order of 3.4 105^{-5} yr1^{-1}. We predict one detection every 148 and 125 years with initial VIRGO and LIGO, and up to 6 events per year with their advanced configuration. Our recent detection rate estimates from investigations on VIRGO future improvements are quoted.Comment: talk given at the GWDAW9 (Annecy, 2004) to be published in CQ

    Efficacy and safety of percutaneous radiofrequency thermal ablation in the treatment of lung cancer lesions.

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    INTRODUCTION: In this study, we reviewed a clinical series composed by all malignant lung lesions submitted to computed tomography-guided percutaneous thermal radiofrequency ablation, in our hospital, a rather recent technique that has been gaining scientific recognition. MATERIAL AND METHODS: For data purposes, all radiofrequency ablation and corresponding clinical records were retrospectively analysed. A computed tomography scan was performed before and after each procedure to evaluate the tumour's features, and at a second step to assess results and complications. The frequency of local recurrence and disease progression were determined based on imaging follow-up. Kaplan-Meier analysis was used to estimate survival. Univariate analysis recognized clinical and pathological factors affecting survival. These were also tested by multivariate analysis. RESULTS: A total of 28 malignant lung lesions, 20 primary and 8 metastatic, from 28 patients (78.6% male; mean age 62 ± 17 years old), were submitted to computed tomography-guided radiofrequency ablation between January 2004 and July 2010. Total necrosis was achieved in 74.1% of the lesions. Immediate radiofrequency ablation-related complications were observed in half of the procedures. Among major complications, death occurred in one patient only. Median overall survival was 43.0 months for a mean 2-years follow-up.Median progression-free survival was 31.6 months. Lesion's size smaller than 35 mm, stage III disease by the TNM classification and previous treatment attempts were significantly associated with better outcomes. Disease-related mortality was 46.4%. DISCUSSION: This procedure proved to be efficient to treat lung cancerous lesions, with a low-rate of major complications. CONCLUSIONS: Computed tomography-guided percutaneous radiofrequency ablation is a minimally invasive procedure that appears to be valuable in the treatment of lung cancer lesions

    Balanço energético e proteico de rações para suínos machos, inteiros e castrados, de diferentes raças e pesos.

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    Determinar o efeito do sexo( animais inteiros e castrados) da raça(Landrace, Large white e cruza landrace X large white) e dos pesos ou períodos sobre o balanço energético e proteico de uma ração que tinha por base milho e farelo de soja para suínos

    Resistência do solo à penetração em diferentes fitofisionomias no Pantanal da Nhecolândia.

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    Este trabalho teve por objetivo avaliar a resistência do solo à penetração em diferentes fitofisionomias no Pantanal da Nhecolândia, visando subsidiar o manejo sustentável dessas áreas. The objective of this work was to evaluate the soil resistance to penetration in the different vegetation types in the Pantanal Nhecolãndia, South of Mato Grosso, Aiming to subsidise the sustainable management of these areas

    Micronutrientes no solo sob diferentes fitofisionomias no Pantanal da Nhecolândia, Mato Grosso do Sul.

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    O Pantanal da Nhecolândia é caracterizado por uma elevada diversidade de unidades de vegetação que apresentam diferenças na fertilidade do solo. O presente estudo objetivou avaliar a disponibilidade de micronutrientes do solo sob as diferentes fitofisionomias desta região. Amostras de solo foram coletadas na profundidade de 0-10 cm, para avaliação da disponibilidade de zinco, ferro, manganês, cobre, boro e sódio, em sete fitofisionomias sujeitas a diferentes regimes de inundação: a) livres de inundação - floresta semidecídua e cerradão; b) sujeitas a inundação ocasional ? cerrado/campo cerrado e campo limpo com predominância de Elionurus muticus; c) sujeita a inundação sazonal - campo limpo com predominância de Axonopus purpusii e Andropogon spp.; bordas de baías e ?vazantes?/?baixadas?. Os micronutrientes apresentaram elevada variação de disponibilidade no solo, com exceção do cobre, que obteve resultados estatisticamente iguais entre todas as fitofisionomias. A matéria orgânica do solo foi a principal responsável pela disponibilidade de micronutrientes nos solos arenosos do Pantanal e destaca-se como fonte de reserva de nutrientes nestes ecossistemas. The Pantanal of the Nhecolândia is characterized by a high diversity of vegetation units that differ in soil fertility. This study aimed to assess the availability of micronutrients in the soil under different vegetation types from this region. Soil samples were collected at 0-10 and 10-20 cm depths, to evaluate the availability of zinc, iron, manganese, copper, boron and sodium, in seven different vegetation types subject to different flooding regimes: a) flooding free ? semideciduous forest and forested savannah; b) subject to occasional flooding ? savannah/arboreal savannah and tropical grassland with predominance of Elionurus muticus; c) subject to seasonal flooding - tropical grassland with predominance of Axonopus purpusii and Andropogon spp.; edge of ponds and temporary channels and lowlands. The availability of micronutrients in the soil showed high variability, with the exception of copper, which obtained statistically equal results among all forest types. The soil organic matter was primarily responsible for the availability of micronutrients in sandy soils of the Pantanal and stands as a source of reserve nutrients in these ecosystems.bitstream/item/57009/1/BP114.pd
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