1,901 research outputs found

    Best of Both Worlds – Relational Databases and Statistics

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    Statistics software packages and relational database systems possess considerable overlap in the area of data loading, handling, and transformation. However, only databases are mainly optimized towards high performance in this area. In this paper, we present our approach on bringing the best of these two worlds together. We integrate the analytics-optimized database MonetDB and the R environment for statistical computing in a non-obtrusive, transparent and compatible way

    Single polymer dynamics: coil-stretch transition in a random flow

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    By quantitative studies of statistics of polymer stretching in a random flow and of a flow field we demonstrate that the stretching of polymer molecules in a 3D random flow occurs rather sharply via the coil-stretch transition at the value of the criterion close to theoretically predicted.Comment: 4 pages, 5 figure

    Hydrogen solubility in zirconium intermetallic second phase particles

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    The enthalpies of solution of H in Zr binary intermetallic compounds formed with Cu, Cr, Fe, Mo, Ni, Nb, Sn and V were calculated by means of density functional theory simulations and compared to that of H in {\alpha}-Zr. It is predicted that all Zr-rich phases (formed with Cu, Fe, Ni and Sn), and those phases formed with Nb and V, offer lower energy, more stable sites for H than {\alpha}-Zr. Conversely, Mo and Cr containing phases do not provide preferential solution sites for H. In all cases the most stable site for H are those that offer the highest coordination fraction of Zr atoms. Often these are four Zr tetrahedra but not always. Implications with respect to H-trapping properties of commonly observed ternary phases such as Zr(Cr,Fe)2, Zr2(Fe,Ni) and Zr(Nb,Fe)2 are also discussed.Comment: manuscript accepted for publication in Journal of Nuclear Materials (2013

    Hispanic College Students Library Experience

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    This study looks at undergraduate Hispanic students’ interpretations and current perceptions of the academic library’s purpose, usefulness and value. What are the reasons to use the library? What are the barriers to use? This study will examine academic libraries’ move toward electronic library materials and what it means for Hispanic students. The results of this study will help academic libraries at Hispanic Serving Institutions to better understand how they are currently being perceived and what they need to do to market themselves and their collections to better serve Hispanic students

    The clock is ticking : temporally prioritizing eradications on islands

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    Funding Funding was awarded to Z.T.C. by the New Zealand Government through a New Zealand International Doctoral Research Scholarship. Funding was awarded to T.W.B. by the European Union's Horizon 2020 research and innovation programme Marie SkƂodowska Curie Fellowship (Grant No. 747120). Funding was awarded to J.C.R. by the Royal Society of New Zealand Rutherford Discovery Fellowship (Grant No. RDF-UOA1404) and the BioHeritage National Science Challenge (Grant No. 1617-44-003). Additional supporting information may be found in the supplementary material of this article. The associated code and dataset are archived and are publicly available at the University of Auckland figshare database (https://doi.org/10.17608/k6.auckland.13542203.v1) and at GitHub (https://github.com/carterz2/temporal‐island‐prioritization).Peer reviewedPostprin

    Can electronic assessment tools improve the process of shared decision-making? A systematic review

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    Background: Patient involvement in decision-making plays a prominent role in improving the quality of healthcare. Despite this, shared decision-making is not routinely implemented. However, electronic assessment tools that capture patients’ history, symptoms, opinions and values prior to their medical appointment are used by healthcare professionals during patient consultations to facilitate shared decision-making. Objective: To assess the effectiveness of electronic assessment tools to improve the shared decision-making process. Method: A systematic review was conducted following PRISMA guidelines. Published literature was searched on MEDLINE, EMBASE and PsycINFO to identify potentially relevant studies. Data were extracted and analysed narratively. Results: Seventeen articles, representing 4004 participants, were included in this review. The main findings were significant improvement in patient–provider communication and provider management of patient condition in the intervention group compared to the control group. In contrast, patient–provider satisfaction and time efficiency were assessed by relatively few included studies, and the effects of these outcomes were inconclusive. Conclusion: This review found that communication and healthcare professional’s management of a patient’s condition improves because of the use of electronic questionnaires. This is encouraging because the process of shared decision-making is reliant on high-quality communication between healthcare professionals and patients. Implications: We found that this intervention is especially important for people with chronic diseases, as they need to establish a long-term relationship with their healthcare provider and agree to a treatment plan that aligns with their values. More rigorous research with validated instruments is required

    Stretching of polymers in a random three-dimensional flow

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    Behavior of a dilute polymer solution in a random three-dimensional flow with an average shear is studied experimentally. Polymer contribution to the shear stress is found to be more than two orders of magnitude higher than in a laminar shear flow. The results indicate that the polymer molecules get strongly stretched by the random motion of the fluid.Comment: 4 pages, 3 figure

    Stabilization of Hydrodynamic Flows by Small Viscosity Variations

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    Motivated by the large effect of turbulent drag reduction by minute concentrations of polymers we study the effects of a weakly space-dependent viscosity on the stability of hydrodynamic flows. In a recent Letter [Phys. Rev. Lett. {\bf 87}, 174501, (2001)] we exposed the crucial role played by a localized region where the energy of fluctuations is produced by interactions with the mean flow (the "critical layer"). We showed that a layer of weakly space-dependent viscosity placed near the critical layer can have a very large stabilizing effect on hydrodynamic fluctuations, retarding significantly the onset of turbulence. In this paper we extend these observation in two directions: first we show that the strong stabilization of the primary instability is also obtained when the viscosity profile is realistic (inferred from simulations of turbulent flows with a small concentration of polymers). Second, we analyze the secondary instability (around the time-dependent primary instability) and find similar strong stabilization. Since the secondary instability develops around a time-dependent solution and is three-dimensional, this brings us closer to the turbulent case. We reiterate that the large effect is {\em not} due to a modified dissipation (as is assumed in some theories of drag reduction), but due to reduced energy intake from the mean flow to the fluctuations. We propose that similar physics act in turbulent drag reduction.Comment: 10 pages, 17 figs., REVTeX4, PRE, submitte
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