8,482 research outputs found

    Fission products of superheavy elements. An investigation of the naturally occurring fission products of elements heavier than uranium

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    Fission mass yields in different structural elements and mineral separates were studied for the element X. The fission component for Pu-244, and the element X are discussed along with radiogenic Xe-129 and neutron activitation

    Clusters and cycles in the cosmic ray age distributions of meteorites

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    Statistically significant clusters in the cosmic ray exposure age distributions of some groups of iron and stone meteorites were observed, suggesting epochs of enhanced collision and breakups. Fourier analyses of the age distributions of chondrites reveal no significant periods, nor does the same analysis when applied to iron meteorite clusters

    Intra-Articular Osteotomy for Distal Humerus Malunion

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    Intra-articular osteotomy is considered in the rare case of malunion after a fracture of the distal humerus to restore humeral alignment and gain a functional arc of elbow motion. Traumatic and iatrogenic disruption of the limited blood flow to the distal end of the humerus resulting in avascular necrosis of capitellum or trochlea is a major pitfall of the this technically challenging procedure. Two cases are presented which illustrate the potential problems of intra-articular osteotomy for malunion of the distal humerus

    Isotopic signatures and distribution of nitrogen and trapped and radiogenic xenon in the Acapulco and FRO90011 meteorites

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    Acapulco metal and silicate show distinct N isotopic signatures. Trapped heavy noble gases are carried by 'magnetic' opx and radiogenic Xe-129 excesses are observed in phosphate and in minor surficial phases on metal grains. N and Xe isotopic signatures in FRO90011 do not agree with those observed in Acapulco. The Acapulco meteorite is unique in having achondritic texture and chondritic composition. Its mineralogical study shows the record of high temperature (1100 C) recrystallization. However, this meteorite shows abundances of volatile elements close to the levels observed in carbonaceous chondrites and concentrations of heavy noble gases comparable to those observed in type 4 ordinary chondrites, not expected for a presumed highly equilibrated object. Nitrogen measurements in bulk Acapulco revealed two different isotopic signatures, in apparent conflict with evidence for a high degree of recrystallization. N and Xe were studied in separated mineral phases to search for the carriers in order to better understand the formation and thermal history of the Acapulco parent body

    H-alpha observations of the gamma-ray-emitting Be/X-ray binary LSI+61303: orbital modulation, disk truncation, and long-term variability

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    We report 138 spectral observations of the H-alpha emission line of the radio- and gamma-ray-emitting Be/X-ray binary LSI+61303 obtained during the period of September 1998 -- January 2013. From measuring various H-alpha parameters, we found that the orbital modulation of the H-alpha is best visible in the equivalent width ratio EW(B)/EW(R), the equivalent width of the blue hump, and in the radial velocity of the central dip. The periodogram analysis confirmed that the H-alpha emission is modulated with the orbital and superorbital periods. For the past 20 years the radius of the circumstellar disk is similar to the Roche lobe size at the periastron. It is probably truncated by a 6:1 resonance. The orbital maximum of the equivalent width of H-alpha emission peaks after the periastron and coincides on average with the X-ray and gamma-ray maxima. All the spectra are available upon request from the authors and through the CDS.Comment: 11 pages, accepted for publication in A&

    Effect of iodine in semolina matrices

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    The effect of starch-protein interactions on the ability of linear starch chains to bind iodine was investigated in 4 types of semolina. Based on K/S (absorption/scattering coefficient) spectra, obtained after equilibration above K 2SO 4 and exposure to iodine vapor, and X-ray diffraction, semolina samples showed differences in chain mobility, iodine-binding capacity and crystalline order. After removing protein from the samples, starch exhibited a higher iodine-binding capacity, suggesting greater starch chain mobility, and low crystalline order. The results suggest that protein and/or starch-protein affect the packing arrangement of starch polymers within the granule

    Rice-based pasta: a comparison between conventional pasta-making and extrusion- cooking

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    Good quality gluten-free products continue to be in demand among the celiac community and the production of pasta from non-conventional raw materials is a major technological challenge. In this work, the effects of two different pasta-making processes (conventional and extrusion-cooking) were investigated on parboiled brown and milled rice flours. The two processes differentiated for extrusion temperature (conventional extrusion: 50 C, max; extrusion-cooking: 115 C), whereas the drying diagram was the same. Starch modifications induced by each pasta-making process were analyzed by using a Micro-ViscoAmylo-graph (MVAG), Differential Scanning Calorimetry (DSC), and X-ray Diffraction. The cooking quality was evaluated by weight increase, solid loss into the cooking water, and texture analysis. Pasta obtained from milled rice using the extrusion-cooking process was characterized by the best cooking behavior. In this sample, starch presented the highest peak and final viscosities, the highest gelatinization temperature and lower enthalpy value, and the lowest crystallinity. The cooking quality of pasta obtained from brown rice appeared less affected by the processing conditions. Therefore, the nature and intensity of starch modifications can be modulated by the processing conditions and might explain the different cooking behaviour of rice pasta

    Osteotomy and Autograft Lengthening for Intra-Articular Malunion of the Proximal Ulna: A Case Report

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    An osteotomy with interposition of iliac crest bone graft and lengthening of the proximal ulna can be used to restore ulnohumeral congruency after a malunited comminuted olecranon fracture treated with figure-of-eight tension band wiring
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