2,362 research outputs found

    Steam injection into water-saturated porous rock

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    Steam injection into water-saturated porous rock

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    We formulate conservation laws governing steam injection in a linear porous medium containing water. Heat losses to the outside are neglected. We find a complete and systematic description of all solutions of the Riemann problem for the injection of a mixture of steam and water into a water-saturated porous medium. For ambient pressure, there are three kinds of solutions, depending on injection and reservoir conditions. We show that the solution is unique for each initial data

    HORACE: software for the analysis of data from single crystal spectroscopy experiments at time-of-flight neutron instruments

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    The HORACE suite of programs has been developed to work with large multiple-measurement data sets collected from time-of-flight neutron spectrometers equipped with arrays of position-sensitive detectors. The software allows exploratory studies of the four dimensions of reciprocal space and excitation energy to be undertaken, enabling multi-dimensional subsets to be visualized, algebraically manipulated, and models for the scattering to simulated or fitted to the data. The software is designed to be an extensible framework, thus allowing user-customized operations to be performed on the data. Examples of the use of its features are given for measurements exploring the spin waves of the simple antiferromagnet RbMnF3_{3} and ferromagnetic iron, and the phonons in URu2_{2}Si2_{2}.Comment: 14 pages, 6 figure

    A study of light-induced proton transfer from gas phase (radical) cations to reference bases. bracketing of proton transfer from excited ions and associated reaction kinetics

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    AbstractBy use of Fourier transform ion cyclotron resonance, it is shown that protonated naphthalene when excited with laser light of 488 nm is more reactive in proton transfer to reference bases than in its ground state. The excitation leads to reaction with bases for which proton transfer in the ground state is endothermic up to a detected maximum of 60 kJ/mol. For indene radical cations excited at 514.5 nm, it is shown that the rate constant for proton transfer to 3-pentanone is either about 10 or about 100 times lower than the rate constant for relaxation by collisions with 3-pentanone. From the energy deposited in the ions, 0.5–0.6 eV is available for proton transfer to a base which seems reasonable when taking into account a complete randomization of the initially deposited energy

    No Longer Discrete:Modeling the Dynamics of Social Networks and Continuous Behavior

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    The dynamics of individual behavior are related to the dynamics of the social structures in which individuals are embedded. This implies that in order to study social mechanisms such as social selection or peer influence, we need to model the evolution of social networks and the attributes of network actors as interdependent processes. The stochastic actor-oriented model is a statistical approach to study network-attribute coevolution based on longitudinal data. In its standard specification, the coevolving actor attributes are assumed to be measured on an ordinal categorical scale. Continuous variables first need to be discretized to fit into such a modeling framework. This article presents an extension of the stochastic actor-oriented model that does away with this restriction by using a stochastic differential equation to model the evolution of a continuous attribute. We propose a measure for explained variance and give an interpretation of parameter sizes. The proposed method is illustrated by a study of the relationship between friendship, alcohol consumption, and self-esteem among adolescents

    Consensus about GP interprofessional competencies:A nominal group study

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    BACKGROUND: Since the requirements for collaboration in primary care increase, effective interprofessional teamwork between general practitioners (GPs) and other primary care professionals is crucial. The need for more training in interprofessional collaborative competencies is widely recognised. However, existing competency frameworks do not sufficiently specify interprofessional collaboration to guide interprofessional competency development. AIM: Consensus among GPs and other primary care professionals on interprofessional competencies that GP and GP-trainees should learn. DESIGN & SETTING: Qualitative consensus study among Dutch GPs and other primary care professionals, all with expertise in primary care interprofessional collaborative practice. METHOD: Three nominal group sessions were held, each resulting in its own group consensus on GP interprofessional collaborative competencies. The researchers conducted a content analysis to merge and thematise the prioritised competencies into one list. Participants prioritised this list of competencies. A pre-set cut-off point was applied to determine the overall consensus on core GP interprofessional competencies. RESULTS: Eighteen professionals from nine different disciplines participated. The content analysis resulted in 31 unique competencies of which fourteen competencies were prioritised in the final ranking into three main themes: 1. Professional identity development and role definition by the GP. (three competencies); 2. Developing and executing shared care plans for individual patients (6); 3. Setting up and maintaining interprofessional collaborative partnerships.(5) CONCLUSION: An interprofessional group of experts reached consensus on 14 competencies within 3 themes. This framework provides a steppingstone for GPs to focus on their development regarding interprofessional collaboration

    Developing a set of ancestry-sensitive DNA markers reflecting continental origins of humans

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    Background: The identification and use of Ancestry-Sensitive Markers (ASMs), i.e. genetic polymorphisms facilitating the genetic reconstruction of geographical origins of individuals, is far from straightforward. Results: Here we describe the ascertainment and application of five different sets of 47 single nucleotide polymorphisms (SNPs) allowing the inference of major human groups of different continental origin. For this, we first used 74 cell lines, representing human males from six different geographical areas and screened them with the Affymetrix Mapping 10K assay. In addition to using summary statistics estimating the genetic diversity among multiple groups of individuals defined by geography or language, we also used the program STRUCTURE to detect genetically distinct subgroups. Subsequently, we used a pairwise FSTranking procedure among all pairs of genetic subgroups in order to identify a single best performing set of ASMs. Our initial results were independently confirmed by genotyping this set of ASMs in 22 individuals from Somalia, Afghanistan and Sudan and in 919 samples from the CEPH Human Genome Diversity Panel (HGDP-CEPH). Conclusion: By means of our pairwise population FSTranking approach we identified a set of 47 SNPs that could serve as a panel of ASMs at a continental level
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