5,253 research outputs found

    Observations of Mkn 421 with the CELESTE Experiment

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    The CELESTE experiment uses the heliostats of an old solar farm in the French Pyrenees to detect gamma ray air showers by the atmospheric Cerenkov technique. Observations of the TeV blazar Markarian 421 have been made with the fully instrumented CELESTE experiment since December 1999. The detection of gamma ray emission from this source at energies greater than 50 GeV is presented here. A comparison is made with the light curve from the CAT experiment at the same site which shows correlation between the observed gamma ray fluxes and the detection of short duration flaring episodes.Comment: 4 pages, 4 figures. To appear in the Proceedings of the Heidelberg Gamma Ray Symposiu

    Oportunidades e desafios da avaliação de desempenho para o desenvolvimento profissional dos docentes: um estudo a partir das perceções de professores de uma escola básica do distrito de Évora

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    O propósito desta investigação foi analisar a cultura avaliativa de uma escola, considerando o desempenho docente. Conceptualmente, foram aprofundados os temas da profissionalidade docente (identidade, conhecimento, desenvolvimento profissional e organizacional) e os eixos estruturantes da avaliação no contexto atual. Salientou-se o papel da reflexão, da supervisão e do feedback construtivo, advogando-se a avaliação enquanto projeto, inserida numa cultura singular. Daí decorreu o desenho metodológico, configurando um estudo exploratório, descritivo da cultura escolar, no que diz respeito às perceções dos professores efetivos sobre o desempenho do trabalho docente. Optou-se pela leitura dos documentos de gestão pedagógica e pelo ques-tionário, enquanto instrumentos de recolha de dados. Os resultados do estudo empírico tenderam a revelar uma propensão favorável aos assuntos abordados. A avaliação do desempenho docente, encarada numa perspetiva formativa, pareceu surgir, naquela escola, como uma oportunidade de aprendizagem que enforma toda a complexidade do ato de ensinar

    LINX®, a novel treatment for patients with refractory asthma complicated by gastroesophageal reflux disease: a case report.

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    BackgroundGastroesophageal reflux disease is one of the most common comorbidities in patients with asthma. Gastroesophageal reflux disease can be linked to difficult-to-control asthma. Current management includes gastric acid suppression therapy and surgical antireflux procedures. The LINX® procedure is a novel surgical treatment for patients with gastroesophageal reflux disease refractory to medical therapy. To the best of our knowledge, we report the first case of successful treatment of refractory asthma secondary to gastroesophageal reflux disease using the LINX® procedure.Case presentationOur patient was a 22-year-old white woman who met the American Thoracic Society criteria for refractory asthma that had remained poorly controlled for 5 years despite progressive escalation to step 6 treatment as recommended by National Institutes of Health-National Asthma Education and Prevention Program guidelines, including high-dose oral corticosteroids, high-dose inhaled corticosteroid plus long-acting β2-agonist, leukotriene receptor antagonist, and monthly omalizumab. Separate trials with azithromycin therapy and roflumilast did not improve her asthma control, nor did bronchial thermoplasty help. Additional consultations with two other university health systems left the patient with few treatment options for asthma, which included cyclophosphamide. Instead, the patient underwent a LINX® procedure after failure of maximal medical therapy for gastroesophageal reflux disease with the additional aim of improving asthma control. After she underwent LINX® treatment, her asthma improved dramatically and was no longer refractory. She had normal exhaled nitric oxide levels and loss of peripheral eosinophilia after LINX® treatment. Prednisone was discontinued without loss of asthma control. The only immediate adverse effects due to the LINX® procedure were bloating, nausea, and vomiting.ConclusionsLINX® is a viable alternative to the Nissen fundoplication procedure for the treatment of patients with gastroesophageal reflux disease and poorly controlled concomitant refractory asthma

    Mode Identification from Combination Frequency Amplitudes in ZZ Ceti Stars

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    The lightcurves of variable DA stars are usually multi-periodic and non-sinusoidal, so that their Fourier transforms show peaks at eigenfrequencies of the pulsation modes and at sums and differences of these frequencies. These combination frequencies provide extra information about the pulsations, both physical and geometrical, that is lost unless they are analyzed. Several theories provide a context for this analysis by predicting combination frequency amplitudes. In these theories, the combination frequencies arise from nonlinear mixing of oscillation modes in the outer layers of the white dwarf, so their analysis cannot yield direct information on the global structure of the star as eigenmodes provide. However, their sensitivity to mode geometry does make them a useful tool for identifying the spherical degree of the modes that mix to produce them. In this paper, we analyze data from eight hot, low-amplitude DAV white dwarfs and measure the amplitudes of combination frequencies present. By comparing these amplitudes to the predictions of the theory of Goldreich & Wu, we have verified that the theory is crudely consistent with the measurements. We have also investigated to what extent the combination frequencies can be used to measure the spherical degree (ell) of the modes that produce them. We find that modes with ell > 2 are easily identifiable as high ell based on their combination frequencies alone. Distinguishing between ell=1 and 2 is also possible using harmonics. These results will be useful for conducting seismological analysis of large ensembles of ZZ Ceti stars, such as those being discovered using the Sloan Digital Sky Survey. Because this method relies only on photometry at optical wavelengths, it can be applied to faint stars using 4 m class telescopes.Comment: 73 pages, 22 figures, accepted in the Ap

    Ca II triplet spectroscopy of small magellanic cloud red giants. II. abundances for a sample of field stars

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    We have obtained metallicities of ∼360 red giant stars distributed in 15 Small Magellanic Cloud (SMC) fields from near-infrared spectra covering the Ca II triplet lines using the VLT + FORS2. The errors of the derived [Fe/H] values range from 0.09 to 0.35 dex per star, with a mean of 0.17 dex. The metallicity distribution (MD) of the whole sample shows a mean value of [Fe/H] = -1.00 ± 0.02, with a dispersion of 0.32 0.01, in agreement with global mean [Fe/H] values found in previous studies. We find no evidence of a metallicity gradient in the SMC. In fact, on analyzing the MD of each field, we derived mean values of [Fe/H] = -0.99 ± 0.08 and [Fe/H] = -1.02 ± 0.07 for fields located closer and farther than 4° from the center of the galaxy, respectively. In addition, there is a clear tendency for the field stars to be more metal-poor than the corresponding cluster they surround, independent of their positions in the galaxy and of the clusters' age. We argue that this most likely stems from the field stars being somewhat older and therefore somewhat more metal-poor than most of our clusters. © 2010. The American Astronomical Society.Fil: Parisi, Maria Celeste. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; ArgentinaFil: Geisler, Doug. Universidad de Concepción; ChileFil: Grocholski, A. J.. University of Florida; Estados Unidos. Space Telescope Science Institute; Estados UnidosFil: Claria Olmedo, Juan Jose. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; ArgentinaFil: Sarajedini, A.. University of Florida; Estados Unido

    Plano de mobilidade sustentável de Loulé: relatório de objectivos e conceito de intervenção

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    Este relatório apresenta os objetivos e o conceito de intervenção do Plano de Mobilidade Sustentável de Loulé. Tendo como referencial de enquadramento um conjunto de documentos europeus e nacionais de publicação recente, estabelecem-se princípios e estratégias convergentes para uma mobilidade sustentável e definem-se os objectivos gerais. Apresentam-se três cenários alternativos, em cuja explicitação se recorre às diferentes áreas de intervenção, distinguindo-se cada um deles pelos níveis de acentuação das acções previstas em cada domínio.N/
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