1,217 research outputs found

    Isolated Splenic Metastasis from Colorectal Cancer: Report of a Case

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    The authors report a case of a patient with splenic metastasis with previous history of colorectal cancer. A 69-year-old woman underwent a left hemicolectomy for sigmoid colon cancer. The tumor was staged T3N0M0. Two years after the operation, there was an elevation of CEA and computed tomography (CT) scan revealed a mass in the spleen, considered as an isolated metastasis. The patient underwent splenectomy. Histological diagnosis confirmed a metastatic adenocarcinoma from colorectal carcinoma. Patient was alive without neoplasic recurrence 5 years after splenectomy. Generally, splenic metastasis is uncommon. However, with the case of colorectal cancers, metastasis to the spleen is particularly rare. As with splenic metastasis of all primary tumors, the literature recommends that the treatment, where possible, is surgical

    Simulations for single-dish intensity mapping experiments

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    HI intensity mapping is an emerging tool to probe dark energy. Observations of the redshifted HI signal will be contaminated by instrumental noise, atmospheric and Galactic foregrounds. The latter is expected to be four orders of magnitude brighter than the HI emission we wish to detect. We present a simulation of single-dish observations including an instrumental noise model with 1/f and white noise, and sky emission with a diffuse Galactic foreground and HI emission. We consider two foreground cleaning methods: spectral parametric fitting and principal component analysis. For a smooth frequency spectrum of the foreground and instrumental effects, we find that the parametric fitting method provides residuals that are still contaminated by foreground and 1/f noise, but the principal component analysis can remove this contamination down to the thermal noise level. This method is robust for a range of different models of foreground and noise, and so constitutes a promising way to recover the HI signal from the data. However, it induces a leakage of the cosmological signal into the subtracted foreground of around 5%. The efficiency of the component separation methods depends heavily on the smoothness of the frequency spectrum of the foreground and the 1/f noise. We find that as, long as the spectral variations over the band are slow compared to the channel width, the foreground cleaning method still works.Comment: 14 pages, 12 figures. Submitted to MNRA

    Asteroseismic Theory of Rapidly Oscillating Ap Stars

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    This paper reviews some of the important advances made over the last decade concerning theory of roAp stars.Comment: 9 pages, 5 figure

    Benefits of Urologic-Dermatologic Consultations for the Diagnosis of Cutaneous Penile Lesions: A Prospective Study

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    INTRODUCTION: We evaluated the benefits of a specialized consultation created in 2014 for cutaneous penile lesions. MATERIALS AND METHODS: We performed a descriptive prospective study evaluating all patients sent for a monthly urologic-dermatologic consultation at a French university hospital from September 2014 to September 2015 for cutaneous penile lesions. All patients evaluated were included. We collected the demographic data, clinical examination findings, and the proposed diagnosis and treatment for every patient. RESULTS: A total of 27 patients were included; 4 (14.8%) had been referred by a general physician and 23 (85.2%) by a specialist. Cutaneous penile lesions had evolved within 12 months in 15 patients (55.6%). Penile cancer was diagnosed in 5 patients (18.5%), of which 3 were squamous cell carcinoma (11.1%), 1 was metastasis of melanoma (3.7%), and 1 was extramammary Paget disease (3.7%). In addition, 1 patient (3.7%) had a premalignant lesion on a condyloma, 12 (44.4%) had balanitis, 2 (7.4%) had psoriasis lesions, 3 (11.1%) had condylomas, 1 (3.7%) had genital melanosis, and 3 (11.2%) had normal findings. Four patients (16.6%) underwent biopsy, 8 (33.3%) underwent surgery, and 12 (50%) received local treatment. CONCLUSION: The use of urologic-dermatology specialized consultations resulted in encouraging findings. Patients can benefit from multidisciplinary expertise and rapid treatment of various disorders. Thus, it seems important to develop reference centers created specifically for cancerous disease

    A large sample of calibration stars for Gaia: log g from Kepler and CoRoT

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    Asteroseismic data can be used to determine surface gravities with precisions of < 0.05 dex by using the global seismic quantities Deltanu and nu_max along with Teff and [Fe/H]. Surface gravity is also one of the four stellar properties to be derived by automatic analyses for 1 billion stars from Gaia data (workpackage GSP_Phot). We explore seismic data from MS F, G, K stars (solar-like stars) observed by Kepler as a potential calibration source for methods that Gaia will use for object characterisation (log g). We calculate log g for bright nearby stars for which radii and masses are known, and using their global seismic quantities in a grid-based method, we determine an asteroseismic log g to within 0.01 dex of the direct calculation, thus validating the accuracy of our method. We find that errors in Teff and mainly [Fe/H] can cause systematic errors of 0.02 dex. We then apply our method to a list of 40 stars to deliver precise values of surface gravity, i.e. sigma < 0.02 dex, and we find agreement with recent literature values. Finally, we explore the precision we expect in a sample of 400+ Kepler stars which have their global seismic quantities measured. We find a mean uncertainty (precision) on the order of <0.02 dex in log g over the full explored range 3.8 < log g < 4.6, with the mean value varying only with stellar magnitude (0.01 - 0.02 dex). We study sources of systematic errors in log g and find possible biases on the order of 0.04 dex, independent of log g and magnitude, which accounts for errors in the Teff and [Fe/H] measurements, as well as from using a different grid-based method. We conclude that Kepler stars provide a wealth of reliable information that can help to calibrate methods that Gaia will use, in particular, for source characterisation with GSP_Phot where excellent precision (small uncertainties) and accuracy in log g is obtained from seismic data.Comment: Accepted MNRAS, 15 pages (10 figures and 3 tables), v2=some rewording of two sentence

    Relativistic and Radiative Energy Shifts for Rydberg States

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    We investigate relativistic and quantum electrodynamic effects for highly-excited bound states in hydrogenlike systems (Rydberg states). In particular, hydrogenic one-loop Bethe logarithms are calculated for all circular states (l = n-1) in the range 20 <= n <= 60 and successfully compared to an existing asymptotic expansion for large principal quantum number n. We provide accurate expansions of the Bethe logarithm for large values of n, for S, P and circular Rydberg states. These three expansions are expected to give any Bethe logarithms for principal quantum number n > 20 to an accuracy of five to seven decimal digits, within the specified manifolds of atomic states. Within the numerical accuracy, the results constitute unified, general formulas for quantum electrodynamic corrections whose validity is not restricted to a single atomic state. The results are relevant for accurate predictions of radiative shifts of Rydberg states and for the description of the recently investigated laser-dressed Lamb shift, which is observable in a strong coherent-wave light field.Comment: 8 pages; RevTeX

    Synthesis and characterization of core-shell structure silica-coated Fe29.5Ni70.5 nanoparticles

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    In view of potential applications of magnetic particles in biomedicine and electromagnetic devices, we made use of the classical Stober method base-catalysed hydrolysis and condensation of tetraethoxysilane (TEOS) to encapsulate FeNi nanoparticles within a silica shell. An original stirring system under high power ultrasounds made possible to disperse the otherwise agglomerated particles. Sonication guaranteed particles to remain dispersed during the Stober synthesis and also improved the efficiency of the method. The coated particles are characterized by electron microscopy (TEM) and spectroscopy (EDX) showing a core-shell structure with a uniform layer of silica. Silica-coating does not affect the core magnetic properties. Indeed, all samples are ferromagnetic at 77 K and room temperature and the Curie point remains unchanged. Only the coercive force shows an unexpected non-monotonous dependence on silica layer thickness.Comment: Regular paper submited to international peer-reveiwed journa

    Evolution of INPOP planetary ephemerides and Bepi-Colombo simulations

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    We give here a detailed description of the latest INPOP planetary ephemerides INPOP20a. We test the sensitivity of the Sun oblateness determination obtained with INPOP to different models for the Sun core rotation. We also present new evaluations of possible GRT violations with the PPN parameters ÎČ\beta,Îł\gamma and Ό˙/ÎŒ\dot{\mu}/\mu. With a new method for selecting acceptable alternative ephemerides we provide conservative limits of about 7.16×10−57.16 \times 10^{-5} and 7.49×10−57.49 \times 10^{-5} for ÎČ−1\beta-1 and γ−1\gamma-1 respectively using the present day planetary data samples. We also present simulations of Bepi-Colombo range tracking data and their impact on planetary ephemeris construction. We show that the use of future BC range observations should improve these estimates, in particular Îł\gamma. Finally, interesting perspectives for the detection of the Sun core rotation seem to be reachable thanks to the BC mission and its accurate range measurements in the GRT frame.Comment: Proceedings of the IAU Symposium 364 "Multi-scale dynamics of space objects

    The fundamental parameters of the roAp star 10 Aql

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    Due to the strong magnetic field and related abnormal surface layers existing in rapidly oscillating Ap stars, systematic errors are likely to be present when determining their effective temperatures, which potentially compromises asteroseismic studies of these pulsators. Using long-baseline interferometry, our goal is to determine accurate angular diameters of a number of roAp targets to provide a temperature calibration for these stars. We obtained interferometric observations of 10 Aql with the visible spectrograph VEGA at the CHARA array. We determined a limb-darkened angular diameter of 0.275+/-0.009 mas and deduced a linear radius of 2.32+/-0.09 R_sun. We estimated the star's bolometric flux and used it, in combination with its parallax and angular diameter, to determine the star's luminosity and effective temperature. For two data sets of bolometric flux we derived an effective temperature of 7800+/-170 K and a luminosity of 18+/-1 L_sun or of 8000+/-210 K and 19+/-2 L_sun. We used these fundamental parameters together with the large frequency separation to constrain the mass and the age of 10 Aql, using the CESAM stellar evolution code. Assuming a solar chemical composition and ignoring all kinds of diffusion and settling of elements, we obtained a mass of 1.92 M_sun and an age of 780 Gy or a mass of 1.95 M_sun and an age of 740 Gy, depending on the considered bolometric flux. For the first time, we managed to determine an accurate angular diameter for a star smaller than 0.3 mas and to derive its fundamental parameters. In particular, by only combining our interferometric data and the bolometric flux, we derived an effective temperature that can be compared to those derived from atmosphere models. Such fundamental parameters can help for testing the mechanism responsible for the excitation of the oscillations observed in the magnetic pulsating stars
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