1,084 research outputs found

    Valence Instability of YbCu2_2Si2_2 through its quantum critical point

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    We report Resonant inelastic x-ray scattering measurements (RIXS) in YbCu2_2Si2_2 at the Yb L3_{3} edge under high pressure (up to 22 GPa) and at low temperatures (down to 7 K) with emphasis on the vicinity of the transition to a magnetic ordered state. We find a continuous valence change towards the trivalent state with increasing pressure but with a pronounced change of slope close to the critical pressure. Even at 22 GPa the Yb+3^{+3} state is not fully achieved. The pressure where this feature is observed decreases as the temperature is reduced to 9 GPa at 7K, a value close to the critical pressure (\itshape{p\normalfont{c_c}}\normalfont \approx 7.5 GPa) where magnetic order occurs. The decrease in the valence with decreasing temperature previously reported at ambient pressure is confirmed and is found to be enhanced at higher pressures. We also compare the f electron occupancy between YbCu2_2Si2_2 and its Ce-counterpart, CeCu2_2Si2_2

    HORIZONTAL TWO-PHASE FLOW PATTERN RECOGNITION

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    In the present work a Wire Mesh Sensor (WMS) has been adopted to characterize the air-water two-phase flow in a test section consisting of a horizontal Plexiglas pipe of internal diameter 19.5 mm and total length of about 6 m. The flow quality ranges from 0 to 0.73 and the superficial velocity ranges from 0.145 to 31.94 m/s for air and from 0.019 to 2.62 m/s for water. The observed flow patterns are stratified-bubble-slug/plug-annular. The WMS consists of two planes of parallel wire grids (16x16) that are placed across the channel at 1.5 mm and span over the measuring cross section. The wires of both planes cross under an angle of 90°, with a diameter Dwire of 70 μm and a pitch equal to 1.3 mm. The void fraction profiles are derived from the sensor data and their evolution in time and space is analyzed and discussed. The dependence of the signals on the measured fluid dynamic quantities is discussed too. The main task is to predict which flow pattern will exist under any set of operating conditions as well as to predict the value of characteristic flow parameters

    Casimir-Polder intermolecular forces in minimal length theories

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    Generalized uncertainty relations are known to provide a minimal length β\hbar\sqrt{\beta}. The effect of such minimal length in the Casimir-Polder interactions between neutral atoms (molecules) is studied. The first order correction term in the minimal uncertainty parameter is derived and found to describe an attractive potential scaling as r9r^{-9} as opposed to the well known r7r^{-7} long range retarded potential.Comment: 1 Figure. Version published by Physical Review D. Few references added, typos correcte

    An epidemiologic survey of celiac disease in the Terni area (Umbria, Italy) in 2002-2010

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    The present work is an epidemiology survey of celiac disease in the province of Terni (Umbria, Italy) in 2002?2010. Data were collected from the Local Health Unit (LHU) 4 (ASL 4), Terni database and were extrapolated from the overall population of 232,540 (as of 2010) by identifying residents with prescription charge exemptions for celiac disease-oriented drugs. Prevalence and incidence analysis over the timeframe being examined showed that prevalence (330 cases in 2010) has consistently been increasing from 2002 to 2010, whereas incidence has remained essentially the same with minor, yearly fluctuations. Both prevalence and incidence were higher in females than in males. Most patients were diagnosed as young adults, with the highest rates in the 10-14, 35-40 and 55-60 age groups. Thus, in the area of investigation, there is evidence for consistent delayed diagnosis, raising the possibility that the atypical form the disease, more difficult to recognize and more likely to escape early diagnosis, may have become increasingly commoner over time. Because the current prevalence of the disease in the Terni area is estimated to approximate 1%, the anticipated number of cases should amount to 2,325, which value contrasts with the currently reported 330 diagnoses. It is suggested that the current illnessdefining criteria should be revised so to implement early diagnosis and improve the patients? quality of life and access to treatment
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