2,480 research outputs found

    Detection of Contact Binaries Using Sparse High Phase Angle Lightcurves

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    We show that candidate contact binary asteroids can be efficiently identified from sparsely sampled photometry taken at phase angles >60deg. At high phase angle, close/contact binary systems produce distinctive lightcurves that spend most of the time at maximum or minimum (typically >1mag apart) brightness with relatively fast transitions between the two. This means that a few (~5) sparse observations will suffice to measure the large range of variation and identify candidate contact binary systems. This finding can be used in the context of all-sky surveys to constrain the fraction of contact binary near-Earth objects. High phase angle lightcurve data can also reveal the absolute sense of the spin.Comment: 4 pages, 4 figures, 1 table. Accepted for publication in ApJ

    Transplante alogénico de células estaminais em doentes com síndrome mielodisplásica: análise de acordo com o Índice de Prognóstico Internacional

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    © Ordem dos MédicosWe determined the outcome of patients with myelodysplastic syndrome (MDS) and secondary acute myeloid leukemia (sAML) after allogeneic stem cell transplantation according to their international prognostic scoring system (IPSS) risk categories at diagnosis. A total of 11 females and 7 males, with a median age of 45 years, were transplanted. With a median follow-up of 60 months, the 6-year actuarial event-free survival (EFS) for Less Advanced (Low and Intermediate-1 risk IPSS) and Advanced (Intermediate-2 and High risk IPSS) MDS was 71.4% and 43.6%, respectively (p=0.002). We did not observe a difference in EFS depending on cytogenetics at diagnosis (good risk 53.8% Vs intermediate and high risk 53.3%, p=ns), neither on the type of conditioning regimen used (myeloablative 50% Vs reduced intensity 52.2%, p=ns). Our results support that IPSS score at diagnosis may be used to predict EFS in patients with MDS undergoing allogeneic SCT.Neste estudo avaliámos o valor preditivo do índice prognóstico internacional (IPSS) na altura do diagnóstico em doentes com síndrome mielodisplásica (SMD) e leucemia mielóide aguda secundária submetidos a transplante alogénico de células estaminais. Foram transplantados um total de 11 mulheres e sete homens, com uma mediana de idades de 45 anos. Com um seguimento mediano de 60 meses, a sobrevivência livre de eventos aos 6 anos nos doentes com doença menos avançada (IPSS Risco Baixo e Intermédio 1) e com doença avançada (IPSS Intermédio 2 e Alto Risco) foi de 71.4% e 43.6%, respectivamente (p=0.002). Não observámos diferenças significativas na sobrevivência livre de eventos de acordo com a análise citogenética na altura do diagnóstico (risco bom 53,8% VS risco intermédio e alto 53,3%, p=ns) nem com o tipo de regime de condicionamento utilizado (mieloablativo 50% VS intensidade reduzida 52,2%, p=ns). Os nossos resultados demonstram que o IPSS na altura do diagnóstico pode ser utilizado para predizer a sobrevivência livre de eventos em doentes com SMD submetidos a transplante alogénico de células estaminaisinfo:eu-repo/semantics/publishedVersio

    Quantum critical 5f-electrons avoid singularities in U(Ru,Rh)2Si2

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    We present specific heat measurements of 4% Rh-doped U(Ru,Rh)2Si2 at magnetic fields above the proposed metamagnetic transition field Hm~34 T, revealing striking similarities to the isotructural Ce analog CeRu2Si2, suggesting that strongly renormalized hybridized band models apply equally well to both systems. The vanishing bandwidths as H --> Hm are consistent with a putative quantum critical point close to Hm. The existence of a phase transition into an ordered phase in the vicinity of Hm for 4% Rh-doped U(Ru,Rh)2Si2, but not for CeRu2Si2, is consistent with a stronger super-exchange in the case of the U 5-f system, with irreversible processes at the transition revealing a strong coupling of the 5f orbitals to the lattice, most suggestive of orbital or electric quadrupolar order.Comment: 4 pages, 4 figure

    Near-infrared spatially resolved spectroscopy of (136108) Haumea's multiple system

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    The transneptunian region of the solar system is populated by a wide variety of icy bodies showing great diversity. The dwarf planet (136108) Haumea is among the largest TNOs and displays a highly elongated shape and hosts two moons, covered with crystalline water ice like Hamuea. Haumea is also the largest member of the sole TNO family known to date. A catastrophic collision is likely responsible for its unique characteristics. We report here on the analysis of a new set of observations of Haumea obtained with SINFONI at the ESO VLT. Combined with previous data, and using light-curve measurements in the optical and far infrared, we carry out a rotationally resolved spectroscopic study of the surface of Haumea. We describe the physical characteristics of the crystalline water ice present on the surface of Haumea for both regions, in and out of the Dark Red Spot (DRS), and analyze the differences obtained for each individual spectrum. The presence of crystalline water ice is confirmed over more than half of the surface of Haumea. Our measurements of the average spectral slope confirm the redder characteristic of the spot region. Detailed analysis of the crystalline water-ice absorption bands do not show significant differences between the DRS and the remaining part of the surface. We also present the results of applying Hapke modeling to our data set. The best spectral fit is obtained with a mixture of crystalline water ice (grain sizes smaller than 60 micron) with a few percent of amorphous carbon. Improvements to the fit are obtained by adding ~10% of amorphous water ice. Additionally, we used the IFU-reconstructed images to measure the relative astrometric position of the largest satellite Hi`iaka and determine its orbital elements. An orbital solution was computed with our genetic-based algorithm GENOID and our results are in full agreement with recent results.Comment: Accepted for publication in A&

    Variação da habilidade combinatória em população restauradora para o desenvolvimento de genitores de híbridos de arroz.

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    Baseia-se na exploração da macho-esterilidade genética utilizada na população restauradora em processo de seleção recorrente

    A versatile and compact capacitive dilatometer

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    We describe the design, construction, calibration, and operation of a relatively simple differential capacitive dilatometer suitable for measurements of thermal expansion and magnetostriction from 300 K to below 1 K with a low-temperature resolution of about 0.05 angstroms. The design is characterized by an open architecture permitting measurements on small samples with a variety of shapes. Dilatometers of this design have operated successfully with a commercial physical property measurement system, with several types of cryogenic refrigeration systems, in vacuum, in helium exchange gas, and while immersed in liquid helium (magnetostriction only) to temperatures of 30 mK and in magnetic fields to 45 T.Comment: 8 pages, incorporating 6 figures, submitted to Rev. Sci. Instru

    D-bifunctional protein deficiency – a cause of neonatal onset seizures and hypotonia

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    Background Peroxisomal disorders are classified in two major groups: (1) Peroxisome Biogenesis Disorders and (2) single Peroxisomal Enzyme/Transporter Deficiencies. D-bifunctional protein deficiency (DBP; OMIM #261515) included in this last group of rare diseases leads to an impaired peroxisomal beta-oxidation. D-bifunctional protein deficiencies are classified in four types based on the degree of activity of the 2-enoyl-CoA hydratase and 3-hydroxyacyl-CoA dehydrogenase protein units. Case report/Result The authors present the first portuguese reported type II DBP deficiency patient, whose neonatal clinical picture is indistinguishable from a Zellweger spectrum disease. The clinical features and the neuroimaging findings of polymicrogyria raised suspicion of the diagnosis. After biochemical analysis, DBP deficiency was confirmed with the identification of p.Asn457Tyr (N457Y) mutation, present in homozygosity in HSD17B4 gene. Parents were found to be carriers of the mutated allele, confirming the patient homozygosity status and allowing prenatal diagnosis to future pregnancies. Conclusion D-bifunctional protein deficiency is a rare and severe disease and final diagnosis can only be accomplished after HSD17B4 gene sequencing. Treatment is generally of supportive nature, aimed at improving nutrition and growth, controlling the central nervous system symptoms and limiting the eventual progression of liver disease

    Fertilidade do solo e manejo da adubação NPK para alta produtividade de milho no Brasil Central.

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