3,046 research outputs found

    Properties of ultra-cool dwarfs with Gaia. An assessment of the accuracy for the temperature determination

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    We aimed to assess the accuracy of the Gaia teff and logg estimates as derived with current models and observations. We assessed the validity of several inference techniques for deriving the physical parameters of ultra-cool dwarf stars. We used synthetic spectra derived from ultra-cool dwarf models to construct (train) the regression models. We derived the intrinsic uncertainties of the best inference models and assessed their validity by comparing the estimated parameters with the values derived in the bibliography for a sample of ultra-cool dwarf stars observed from the ground. We estimated the total number of ultra-cool dwarfs per spectral subtype, and obtained values that can be summarised (in orders of magnitude) as 400000 objects in the M5-L0 range, 600 objects between L0 and L5, 30 objects between L5 and T0, and 10 objects between T0 and T8. A bright ultra-cool dwarf (with teff=2500 K and \logg=3.5 will be detected by Gaia out to approximately 220 pc, while for teff=1500 K (spectral type L5) and the same surface gravity, this maximum distance reduces to 10-20 pc. The RMSE of the prediction deduced from ground-based spectra of ultra-cool dwarfs simulated at the Gaia spectral range and resolution, and for a Gaia magnitude G=20 is 213 K and 266 K for the models based on k-nearest neighbours and Gaussian process regression, respectively. These are total errors in the sense that they include the internal and external errors, with the latter caused by the inability of the synthetic spectral models (used for the construction of the regression models) to exactly reproduce the observed spectra, and by the large uncertainties in the current calibrations of spectral types and effective temperatures.Comment: 18 pages, 17 figures, accepted by Astronomy & Astrophysic

    Analytical results for a Bessel function times Legendre polynomials class integrals

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    When treating problems of vector diffraction in electromagnetic theory, the evaluation of the integral involving Bessel and associated Legendre functions is necessary. Here we present the analytical result for this integral that will make unnecessary numerical quadrature techniques or localized approximations. The solution is presented using the properties of the Bessel and associated Legendre functions.Comment: 4 page

    Hmong Adults Self-Rated Oral Health: A Pilot Study

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    Since 1975, the Hmong refugee population in the U.S. has increased over 200%. However, little is known about their dental needs or self-rated oral health (SROH). The study aims were to: (1) describe the SROH, self-rated general health (SRGH), and use of dental/physician services; and (2) identify the factors associated with SROH among Hmong adults. A cross-sectional study design with locating sampling methodology was used. Oral health questionnaire was administered to assess SROH and SRGH, past dental and physician visits, and language preference. One hundred twenty adults aged 18–50+ were recruited and 118 had useable information. Of these, 49% rated their oral health as poor/fair and 30% rated their general health as poor/fair. Thirty-nine percent reported that they did not have a regular source of dental care, 46% rated their access to dental care as poor/fair, 43% visited a dentist and 66% visited a physician within the past 12 months. Bivariate analyses demonstrated that access to dental care, past dental visits, age and SRGH were significantly associated with SROH (P \u3c 0.05). Multivariate analyses demonstrated a strong association between access to dental care and good/excellent SROH. About half of Hmong adults rated their oral health and access to dental care as poor. Dental insurance, access to dental care, past preventive dental/physician visits and SRGH were associated with SROH

    Multielemental analysis of Antarctic soils using calibration free laser-induced breakdown spectroscopy

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    Laser-induced breakdown spectroscopy (LIBS) is a quick technique that allows the analysis of all types of samples without destroying them and with much reduced sample treatment. One of its many applications is the study of geological samples such as soils. Because of the complexity of the matrix, it is very difficult to find or manufacture standards for these types of samples. Therefore, a good alternative is to make use of a methodology, called Calibration Free (CF), where instead of using standards, the physical parameters of the plasma created by the interaction of the laser with the sample are studied and related to the elements and species that compose it. This methodology is followed to perform a multielemental quantitative analysis of soil samples from Antarctica. Two studies were made, differing in the optimization of the instrumental parameters in order to obtain the best possible spectra in the chosen spectral lines. In both cases, the signal to noise ratio (SNR) was used to evaluate the quality of the spectra, but in the second study a full factorial design 23 with center and axial points was developed to get better results. The choice of spectral lines was based on a series of criteria, being stricter in the second study. The samples were mainly composed of the following oxides: SiO2, Al2O3, Fe2O3, CaO, MgO, Na2O, TiO and K2O. In the second study, it was also possible to determine the species present in lower concentrations: Mn, Cr, V, Sr, Zr, BA and Li. The results were compared with those provided by ICP-OES analysis, obtaining close values for most oxides, especially in the second study. For minority elements, the CF-LIBS and the ICP-OES results were within the same order of magnitude in all cases except the Cr case. These results show that CF-LIBS can be very useful in the characterization of complex samples from remote regions, such as Antarctic soils

    Nefrectomia parcial laparoscópica para tumor T2b em paciente com rim único: relato de caso

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    Introdução: Para tumores T2, a maioria dos autores sugere a nefrectomia radical, porém, a literatura carece de relatos de nefrectomia para tumores T2b em pacientes com rim único. Relato de caso: RJAL, sexo masculino, 32 anos com tumor em rim esquerdo medindo 12 cm e agenesia renal direita. No pré-operatório apresentava função renal normal. Foi submetido à nefrectomia parcial laparoscópica em junho de 2016. Evoluiu com elevação da creatinina sérica e anúria, sendo então iniciada terapia renal substitutiva com hemodiálise. Após 20 dias, por apresentar normalização da função renal, optouse por suspender a mesma. O anatomopatológico revelou tratar-se de carcinoma de células renais. No momento, o paciente encontra-se fora de hemodiálise e com TC mostrando rim sem evidências de recidiva tumoral. Comentários: A nefrectomia parcial laparoscópica para tumores renais estádio T2b, é factível e pode ser indicada em casos selecionados como agenesia renal, com resultado oncológico eficaz e manutenção da função renal

    Surveillance for Invasive Meningococcal Disease in Children, US–Mexico Border, 2005–20081

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    We reviewed confirmed cases of pediatric invasive meningococcal disease in Tijuana, Mexico, and San Diego County, California, USA, during 2005–2008. The overall incidence and fatality rate observed in Tijuana were similar to those found in the US, and serogroup distribution suggests that most cases in Tijuana are vaccine preventable

    Redes neuronales aplicadas a la predicción de tráfico en redes convergentes

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    El auge de las telecomunicaciones ha producido una transformación de las tecnologías de la información y de la comunicación, cuyo impacto ha afectado a todos los sectores de la sociedad. Las redes convergentes, se han convertido tanto para empresas y organizaciones públicas o privadas en la manera más rápida, eficiente y segura de transmitir información, compartir aplicaciones, administrar recursos, intercambiar de datos entre usuarios internos; agilizan en un paso gigante al mundo, porque grandes cantidades de información se trasladan de un sitio a otro, siendo su función principal interconectar redes o equipos terminales que se encuentran ubicados a grandes distancias. Estos cambios en el escenario de las TI están activando individual y colectivamente, el crecimiento exponencial en el tráfico de los sitios. Las empresas tendrán que reaccionar a este crecimiento ya que si no se aumentan anchos de banda y se prioriza los nuevos tráficos, se encontrarán que las aplicaciones deberán competir por recursos congestionados. Este proyecto de investigación busca desarrollar un modelo de sistema informático utilizando algoritmos de Inteligencia Artificial, específicamente las Redes Neuronales, para predecir el tráfico en las Redes Globales multiprotocolos.Eje: Agentes y Sistemas InteligentesRed de Universidades con Carreras en Informática (RedUNCI

    A Rapid Host-protein Test for Differentiating Bacterial From Viral Infection: Apollo Diagnostic Accuracy Study

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    OBJECTIVES: To determine the diagnostic accuracy of a rapid host-protein test for differentiating bacterial from viral infections in patients who presented to the emergency department (ED) or urgent care center (UCC). METHODS: This was a prospective multicenter, blinded study. MeMed BV (MMBV), a test based on tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), interferon gamma-inducible protein-10 (IP-10), and C-reactive protein (CRP), was measured using a rapid measurement platform. Patients were enrolled from 9 EDs and 3 UCCs in the United States and Israel. Patients \u3e3 months of age presenting with fever and clinical suspicion of acute infection were considered eligible. MMBV results were not provided to the treating clinician. MMBV results (bacterial/viral/equivocal) were compared against a reference standard method for classification of infection etiology determined by expert panel adjudication. Experts were blinded to MMBV results. They were provided with comprehensive patient data, including laboratory, microbiological, radiological and follow-up. RESULTS: Of 563 adults and children enrolled, 476 comprised the study population (314 adults, 162 children). The predominant clinical syndrome was respiratory tract infection (60.5% upper, 11.3% lower). MMBV demonstrated sensitivity of 90.0% (95% confidence interval [CI]: 80.3-99.7), specificity of 92.8% (90.0%-95.5%), and negative predictive value of 98.8% (96.8%-99.6%) for bacterial infections. Only 7.2% of cases yielded equivocal MMBV scores. Area under the curve for MMBV was 0.95 (0.90-0.99). CONCLUSIONS: MMBV had a high sensitivity and specificity relative to reference standard for differentiating bacterial from viral infections. Future implementation of MMBV for patients with suspected acute infections could potentially aid with appropriate antibiotic decision-making
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