682 research outputs found

    A little respect: four case studies of HCI’s disregard for other disciplines

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    HCI research often demonstrates lack of respect for other disciplines, evidenced by the way work from those disciplines are cited in CHI papers. We present 4 case studies that demonstrate; 1) that HCI researchers sometimes misunderstand and misrepresent work from other disciplines, and 2) how initial misrepresentations can become ‘accepted wisdom ’within HCI. This disregard for other disciplines leads to errors such as authors citing work to support ‘facts’ precisely opposite to those demonstrated by the cited literature. We conclude with recommendations for authors, editors, publishers and readers on how to reduce the risk of such failures

    Ru48 single-nucleon transfer at the barrier

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    Single-nucleon transfer cross sections have been measured for the 48Ti+104Ru reaction over a large angular range at an energy near the Coulomb barrier. Evidence has been found previously in -ray studies for superdeformed shapes in the compound system (152Dy) reached by this reaction. Reaction channels which couple to these shapes may experience interaction time delays, which would be revealed experimentally by broadened angular distributions. Although an enhancement is found in the forward angle Ti49 yields, this enhancement is small and may reflect uncertainties in the analysis

    Seasonal trends and phenology shifts in sea surface temperature on the North American northeastern continental shelf

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    The northeastern North American continental shelf from Cape Hatteras to the Scotian Shelf is a region of globally extreme positive trends in sea surface temperature (SST). Here, a 33-year (1982–2014) time series of daily satellite SST data was used to quantify and map spatial patterns in SST trends and phenology over this shelf. Strongest trends are over the Scotian Shelf (>0.6°C decade –1 ) and Gulf of Maine (>0.4°C decade –1 ) with weaker trends over the inner Mid-Atlantic Bight (~0.3°C decade –1 ). Winter (January–April) trends are relatively weak, and even negative in some areas; early summer (May–June) trends are positive everywhere, and later summer (July–September) trends are strongest (~1.0°C decade –1 ). These seasonal differences shift the phenology of many metrics of the SST cycle. The yearday on which specific temperature thresholds (8° and 12°C) are reached in spring trends earlier, most strongly over the Scotian Shelf and Gulf of Maine (~ –0.5 days year –1 ). Three metrics defining the warmest summer period show significant trends towards earlier summer starts, later summer ends and longer summer duration over the entire study region. Trends in start and end dates are strongest (~1 day year –1 ) over the Gulf of Maine and Scotian Shelf. Trends in increased summer duration are >2.0 days year –1 in parts of the Gulf of Maine. Regression analyses show that phenology trends have regionally varying links to the North Atlantic Oscillation, to local spring and summer atmospheric pressure and air temperature and to Gulf Stream position. For effective monitoring and management of dynamically heterogeneous shelf regions, the results highlight the need to quantify spatial and seasonal differences in SST trends as well as trends in SST phenology, each of which likely has implications for the ecological functioning of the shelf

    Unexpected Behavior of Heavy-Ion Fusion Cross Sections at Extreme Sub-Barrier Energies

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    The excitation function for fusion evaporation in the system was measured over a range in cross section covering 6 orders of magnitude. The cross section exhibits an abrupt decrease at extreme sub-barrier energies. This behavior, which is also present in a few other systems found in the literature, cannot be reproduced with present models, including those based on a coupled-channels approach. Possible causes are discussed, including a dependence on the intrinsic structure of the participants

    Clinical delineation and natural history of the PIK3CA-related overgrowth spectrum.

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    Somatic mutations in the phosphatidylinositol/AKT/mTOR pathway cause segmental overgrowth disorders. Diagnostic descriptors associated with PIK3CA mutations include fibroadipose overgrowth (FAO), Hemihyperplasia multiple Lipomatosis (HHML), Congenital Lipomatous Overgrowth, Vascular malformations, Epidermal nevi, Scoliosis/skeletal and spinal (CLOVES) syndrome, macrodactyly, and the megalencephaly syndrome, Megalencephaly-Capillary malformation (MCAP) syndrome. We set out to refine the understanding of the clinical spectrum and natural history of these phenotypes, and now describe 35 patients with segmental overgrowth and somatic PIK3CA mutations. The phenotypic data show that these previously described disease entities have considerable overlap, and represent a spectrum. While this spectrum overlaps with Proteus syndrome (sporadic, mosaic, and progressive) it can be distinguished by the absence of cerebriform connective tissue nevi and a distinct natural history. Vascular malformations were found in 15/35 (43%) and epidermal nevi in 4/35 (11%) patients, lower than in Proteus syndrome. Unlike Proteus syndrome, 31/35 (89%) patients with PIK3CA mutations had congenital overgrowth, and in 35/35 patients this was asymmetric and disproportionate. Overgrowth was mild with little postnatal progression in most, while in others it was severe and progressive requiring multiple surgeries. Novel findings include: adipose dysregulation present in all patients, unilateral overgrowth that is predominantly left-sided, overgrowth that affects the lower extremities more than the upper extremities and progresses in a distal to proximal pattern, and in the most severely affected patients is associated with marked paucity of adipose tissue in unaffected areas. While the current data are consistent with some genotype-phenotype correlation, this cannot yet be confirmed

    Branching ratio Γα/Γγ of the 4.033 MeV 3/2+ state in 19Ne

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    The branching ratio Γα/Γγ of the 4.033 MeV 3/2+ state in 19Ne plays a crucial role in the breakout from the hot CNO cycle into the rapid proton capture process. This ratio has been studied by making use of the advantages of inverse kinematics. The state was populated via the 3He(20Ne,α) 19Ne* reaction and its decay via γ or α emission was measured by detecting the heavy reaction products (19Ne or 15O) in coincidence in a magnetic spectrograph. An upper limit Γα/Γγ≤6×10-4 has been obtained. With these results, the astrophysical reaction rate for the 15O (α, γ) 19Ne reaction has been calculated. Its influence on the breakout at various astrophysical sites, novas, x-ray bursts, and supermassive stars, is discussed

    Fusion measurements of 12C+12C at energies of astrophysical interest

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    The cross section of the 12C+12C fusion reaction at low energies is of paramount importance for models of stellar nucleosynthesis in different astrophysical scenarios, such as Type Ia supernovae and Xray superbursts, where this reaction is a primary route for the production of heavier elements. In a series of experiments performed at Argonne National Laboratory, using Gammasphere and an array of Silicon detectors, measurements of the fusion cross section of 12C+12C were successfully carried out with the γ and charged-particle coincidence technique in the center-of-mass energy range of 3-5 MeV. These were the first background-free fusion cross section measurements for 12C+12C at energies of astrophysical interest. Our results are consistent with previous measurements in the high-energy region; however, our lowest energy measurement indicates a fusion cross section slightly lower than those obtained with other techniques

    Neutron spectroscopic factors in9Li from2H( 8Li, p)9Li

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    We have studied the 2H(8Li, p)9Li reaction to obtain information on the spins, parities, and single-neutron spectroscopic factors for states in 9Li, using a radioactive 8Li beam. The deduced properties of the lowest three states are compared to the predictions of a number of calculations for the structure of 9Li. The results of ab initio quantum Monte Carlo calculations are in good agreement with the observed properties

    Determination of the 8B Neutrino Spectrum

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    The total energy of the alpha particles, which resulted from the decay of 8B, was measured. A beam of 8B ions was implanted near the midplane of a planar Si detector. This eliminated α-particle energy loss in insensitive regions and allowed the sum energy of the two α particles to be observed with a single detector. The measurement of the 8B β-delayed α apectrum provided direct determination of the 8B neutrino spectrum
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