882 research outputs found

    Observational Δν\Delta\nu-ρˉ\bar\rho relation for δ\delta Sct stars using eclipsing binaries and space photometry

    Full text link
    Delta Scuti (δ\delta Sct) stars are intermediate-mass pulsators, whose intrinsic oscillations have been studied for decades. However, modelling their pulsations remains a real theoretical challenge, thereby even hampering the precise determination of global stellar parameters. In this work, we used space photometry observations of eclipsing binaries with a δ\delta Sct component to obtain reliable physical parameters and oscillation frequencies. Using that information, we derived an observational scaling relation between the stellar mean density and a frequency pattern in the oscillation spectrum. This pattern is analogous to the solar-like large separation but in the low order regime. We also show that this relation is independent of the rotation rate. These findings open the possibility of accurately characterizing this type of pulsator and validate the frequency pattern as a new observable for δ\delta Sct stars.Comment: 11 pages, including 2 pages of appendix, 2 figures, 2 tables, accepted for publication in ApJ

    Metástase ocular como apresentação inicial de carcinoma de células renais: relato de dois casos

    Get PDF
    Authors report the cases of 2 patients who had an ocular lesion as the first sign leading to diagnosis of renal cell carcinoma, an uncommon presentation of this neoplasm. The first patient was a 59-year-old man presented with a mass in the right eye. The histological and immunohistochemical profile of the biopsy showed a probable renal cell carcinoma. A CT scan showed a solid mass in the left kidney. The patient underwent radical nephrectomy and excision of the ocular lesion and had an uneventful evolution. The second patient was a 72-year-old man presenting with an ulcerated lesion on the right inferior tarsal conjunctiva. An excisional biopsy of the lesion showed histological and immunohistochemical patterns of a clear cell carcinoma. Abdominal tomography disclosed a right peripheral renal tumor. A right radical nephrectomy was performed. Renal cell carcinoma may present atypically with metastases to quite uncommon organs. Nephrectomy may be of value in selected cases; the ocular metastases are usually excised for aesthetic and functional reasons.Os autores apresentam dois casos de metástase ocular como o primeiro sinal que levou ao diagnóstico de carcinoma renal, uma apresentação incomum desta neoplasia. O primeiro paciente era um homem de 59 anos com uma massa no olho direito. O perfil histológico e imunohistoquimico demonstraram um provável carcinoma de células renais. A tomografia computadorizada revelou uma massa sólida no rim esquerdo, e o paciente foi submetido a nefrectomia radical esquerda, apresentando uma evolução sem complicações. O segundo paciente era um homem com 72 anos portador de uma lesão ulcerada na conjuntiva tarsal inferior direita. Uma biopsia excisional da lesão demonstrou um padrão histológico e imunohistoquimico de carcinoma de células renais. A tomografia de abdômen demonstrou um tumor periférico em rim direito, sendo o paciente submetido a nefrectomia radical. O carcinoma de células renais pode se apresentar atipicamente com metástases para órgãos incomuns. Nefrectomia pode ser útil em casos selecionados. As metástases oculares geralmente são excisadas por razoes estéticas e funcionais

    La fenêtre

    Get PDF

    Estimativa dos coeficientes específicos de mortalidade infantil segundo peso ao nascer no município de São Paulo (Brasil)

    Get PDF
    Foi estimada a distribuição do peso ao nascer da coorte dos recém-nascidos que deu origem aos óbitos infantis estudados pela Investigação Interamericana de Mortalidade na Infância no projeto de São Paulo (1968-70) e determinados os riscos de óbito associados a cada intervalo de peso de nascimento. Assim, foram apurados coeficientes de mortalidade infantil de 305,5, 50,2 e 34,4 para recém-nascidos de baixo peso, peso deficiente e peso superior a 3.000 g. A comparação destes coeficientes com os registrados na área americana incluída na investigação citada (Califórnia), revelou excesso de mortalidade, particularmente notável não para os recém-nascidos de baixo peso, mas para os recém-nascidos de peso superior a 3.000 g. O ajuste da mortalidade de São Paulo (Brasil) à distribuição do peso ao nascer observada na Califórnia foi capaz de explicar 15% do excesso da mortalidade infantil e 21% do excesso da mortalidade neonatal de São Paulo.By means of the birth-rate distribution found to exist during the Inter-American Investigation of Mortality in Childhood in S. Paulo (1968-70) the infant death rate association with each birth-weight interval was estimated. The infant mortality rates were 305.5, 50.2 and 34.4 respectively for low birth-weight, deficient weight and weight above 3,000 grams. Compared with the rates found in California, USA, by the same Investigation, the infant mortality rates in S. Paulo are higher, particularly for mortality associated with birth-weight of above 3,000 grams. The adjustment of infant mortality rates in S. Paulo according to the birth-weight distribution found in California led to the conclusion that, at that period, only 15% of the excess of the infant mortality of S. Paulo could be attributed exclusively to birth-weight. In the case of neonatal mortality, 21% of the mortality excess in S. Paulo could be attributed to birth-weight

    Safe exposure distances for transcranial magnetic stimulation based on computer simulations

    Get PDF
    The results of a computer simulation examining the compliance of a given transcranial magnetic stimulation device to the 2010 International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines are presented. The objective was to update the safe distance estimates with the most current safety guidelines, as well as comparing these to values reported in previous publications. The 3D data generated was compared against results available in the literature, regarding the MCB-70 coil by Medtronic. Regarding occupational exposure, safe distances of 1.46 m and 0.96 m are derived from the simulation according to the 2003 and 2010 ICNIRP guidelines, respectively. These values are then compared to safe distances previously reported in other studies

    Water use, soil water balance and soil salinization risks of Mediterranean tree orchards in southern Portugal under current climate variability: Issues for salinity control and irrigation management

    Get PDF
    Secondary salinization has long been reported in the Roxo irrigation district (RID), southern Portugal, due to the use of saline-prone irrigation water and the existence of poorly structured soils. This study assessed the soil water and salt budgets in nine commercial orchards located in the RID using the multiple ion chemistry module available in the HYDRUS-1D model during the 2019 and 2020 growing seasons. The studied crops were almond, olive, citrus (orange, mandarin, and clementine), and pomegranate. The model successfully simulated soil water contents measured in the different fields but there was a clear underestimation of the electrical conductivity of the soil saturation paste extract (ECe) in some locations, while simulations of the sodium adsorption ratio (SAR) were generally acceptable. Modeling errors were mostly associated with missing information on fertigation events rather than related to the effects of irrigation water quality. The water and salt balances were also computed for the 1979–2020 period. Considering the probability of non-exceedance of salt accumulation during this period, the risk of salinity build-up was high to very high for the very dry years in most fields, except in the citrus sites. The factors influencing the salt accumulation were the irrigation strategy, the seasonal irrigation and rainfall depths, the duration of the crop growth period, the rainfall distribution in the late and non-growing stages, the soil drainage conditions, and the irrigation water quality. For the current climate conditions and irrigation water quality, the risk of soil salinity levels affecting crop development and yields was found to be minor. This means that, despite salts tended to accumulate in the rootzone over a season, under current conditions the salinity stress did not reach harmful levels for plants. Only in two of the study sites, there was a need to promote salt leaching. Hence, this study shows that soil salinization risks in the study area are low but, for given locations during drier seasons, there is a need for tailored irrigation solutions aimed at the conservation of soil and water resources.info:eu-repo/semantics/publishedVersio

    The fish family Muraenidae: an ideal group for testing at small-scale the coherency of Macaronesia as a biogeographic unit, with the first report on separate fishery statistics

    Get PDF
    : The present study was conceptualized to study the muraenid species (moray eels) occurring around the volcanic archipelagos of the Azores, Madeira, Selvagens, Canary and Cabo Verde islands (eastern-central Atlantic). The biogeographic patterns of these species were analysed and compared. We then hypothesized that this fish family is an ideal group for testing at small-scale the coherency of Macaronesia and its direct biogeographic units: i.e. the Azores, Webbnesia and Cabo Verde, as proposed in recent scientific literature. Additionally, this paper provides for the first time separate fishery statistics for this group in the region that were analysed to contrast the biogeographic results.En prensa1,00

    Accurate ρ̄ and log g of δ Sct stars using Asteroseismology

    Get PDF
    In this work, we present a new method to determine the surface gravity of δ Sct stars. We used a refined Δν=ρ̄ relation and the stellar parallaxes or luminosities to determine their masses and radii. A comparison with the data obtained from the binary analysis, has shown that the values found by both methods are equivalent, within the uncertainties. Moreover, thanks to the refined relation, the uncertainties in log g are of the order of those usually estimated with high-resolution spectroscopy. Because of that, this new method to determine the surface gravity is an important step forward to break the degeneracy problem in the spectroscopic analysis.AGH acknowledges support from Fundação para a Ciência e a Tecnologia (FCT,Portugal) through the fellowship SFRH/BPD/80619/2011 and from grant UID/FIS/04434/2013.AGH, MJPFGM and JCS acknowledge support from the EC Project SPACEINN (FP7-SPACE-2012-312844) .JCSalsoacknowledges funding support from the Spanish “Ministerio de Economía y Competitividad” under“Ramón y Cajal”subprogram. This research made use of the SIMBAD database and the VizieR catalogue access tool operated at CDS, Strasbourg, France, and the SAO/NASA Astrophysics Data System
    corecore