662 research outputs found
The visual sociogram in qualitative and mixed-methods research
The paper investigates the place of visual tools in mixed-methods research on social networks, arguing that they can not only improve the communicability of results, but also support research at the data gathering and analysis stages. Three examples from the authorsâ own research experience illustrate how sociograms can be integrated in multiple ways with other analytical tools, both quantitative and qualitative, positioning visualization at the intersection of varied methods and channelling substantive ideas as well as network insight in a coherent way.
Visualization also facilitates the participation of a broad range of stakeholders, including among others, study participants and non-specialist researchers. It can support the capacity of qualitative and mixed-methods research to reach out to areas of the social that are difficult to circumscribe, such as hidden populations and informal organisations. On this basis, visualization appears as a unique opportunity for mixing methods in the study of social networks, emphasizing both structure and process at the same time
Stimulant Medication and Reading Performance
The study examined the sustained effects of methylphenidate on reading performance in a sample of 42 boys, ages 8 to 11, with attention deficit-hyperactivity disorder (ADHD). Two subgroups were formed based on the presence or absence of co-occurring conduct disorders. Subjects were selected on the basis of their positive response to methylphenidate as determined in a series of original medication trials (Forness, Cantwell, Swanson, Hanna, & Youpa, 1991). For the purpose of this study, subjects were placed on their optimal dose of medication for a 6-week period and then tested on measures of oral reading and reading comprehension equivalent to those used in the original trials, retested after a week without medication (placebo), then tested again the following week after return to medication. Only the subgroup with conduct disorders responded, and this response was limited to reading comprehension improvement in only those subjects who also demonstrated improvement in oral reading on original trials. No response differences were found between subjects with or without learning disabilities.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68569/2/10.1177_002221949202500205.pd
Efficacy of anidulafungin in 539 patients with invasive candidiasis: a patient-level pooled analysis of six clinical trials
Item does not contain fulltextObjectives: To evaluate the efficacy of anidulafungin for the treatment of candidaemia and invasive candidiasis in a large dataset, including patients with deep-seated tissue candidiasis, neutropenia and infection due to non- albicans Candida species. Methods: Data were pooled from six prospective, multicentre, multinational studies: four open-label, non-comparative studies of anidulafungin and two double-blind, double-dummy, randomized studies of anidulafungin versus caspofungin (clinical trial registrations: NCT00496197, NCT00548262, NCT00537329, NCT00689338, NCT00806351 and NCT00805740; ClinicalTrials.gov). In all studies, patients with culture-confirmed invasive candidiasis received a single intravenous (iv) loading dose of anidulafungin 200 mg on day 1, followed by 100 mg once-daily. Switch to oral fluconazole or voriconazole was permitted after 5-10 days of iv treatment in all studies except one. Antifungal treatment (iv plus oral therapy if applicable) was maintained for >/=14 days after the last positive Candida culture. The primary endpoint was successful global response at end of iv therapy (EOivT) in the modified ITT (mITT) population. Results: In total, 539 patients were included (mITT population). The most common baseline Candida species were Candida albicans (47.9%), Candida glabrata (21.0%), Candida tropicalis (13.7%), Candida parapsilosis (13.2%) and Candida krusei (3.5%). Median duration of anidulafungin iv treatment was 10.0 days. The global response success rate at EOivT was 76.4% (95% CI 72.9%-80.0%). All-cause mortality was 13.0% on day 14 and 19.1% on day 28. Adverse events (AEs) were consistent with the known AE profile for anidulafungin. Conclusions: These data demonstrate that anidulafungin is effective for treatment of candidaemia and invasive candidiasis in a broad patient population
Coulomb Gauge QCD, Confinement, and the Constituent Representation
Quark confinement and the genesis of the constituent quark model are examined
in nonperturbative QCD in Coulomb gauge. We employ a self-consistent method to
construct a quasiparticle basis and to determine the quasiparticle interaction.
The results agree remarkably well with lattice computations. They also
illustrate the mechanism by which confinement and constituent quarks emerge,
provide support for the Gribov-Zwanziger confinement scenario, clarify several
perplexing issues in the constituent quark model, and permit the construction
of an improved model of low energy QCD.Comment: 43 pages, 14 figures, revtex, uses psfig.st
Solitons in Triangular and Honeycomb Dynamical Lattices with the Cubic Nonlinearity
We study the existence and stability of localized states in the discrete
nonlinear Schr{\"o}dinger equation (DNLS) on two-dimensional non-square
lattices. The model includes both the nearest-neighbor and long-range
interactions. For the fundamental strongly localized soliton, the results
depend on the coordination number, i.e., on the particular type of the lattice.
The long-range interactions additionally destabilize the discrete soliton, or
make it more stable, if the sign of the interaction is, respectively, the same
as or opposite to the sign of the short-range interaction. We also explore more
complicated solutions, such as twisted localized modes (TLM's) and solutions
carrying multiple topological charge (vortices) that are specific to the
triangular and honeycomb lattices. In the cases when such vortices are
unstable, direct simulations demonstrate that they turn into zero-vorticity
fundamental solitons.Comment: 17 pages, 13 figures, Phys. Rev.
Mass spectrum of the axial-vector hidden charmed and hidden bottom tetraquark states
In this article, we perform a systematic study of the mass spectrum of the
axial-vector hidden charmed and hidden bottom tetraquark states using the QCD
sum rules, and identify the as an axial-vector tetraquark state
tentatively.Comment: 24 pages, 38 figures, slight revisio
Transfer learning for galaxy morphology from one survey to another
© 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society.Deep Learning (DL) algorithms for morphological classification of galaxies have proven very successful, mimicking (or even improving) visual classifications. However, these algorithms rely on large training samples of labelled galaxies (typically thousands of them). A key question for using DL classifications in future Big Data surveys is how much of the knowledge acquired from an existing survey can be exported to a new dataset, i.e. if the features learned by the machines are meaningful for different data. We test the performance of DL models, trained with Sloan Digital Sky Survey (SDSS) data, on Dark Energy survey (DES) using images for a sample of 5000 galaxies with a similar redshift distribution to SDSS. Applying the models directly to DES data provides a reasonable global accuracy ( 90%), but small completeness and purity values. A fast domain adaptation step, consisting in a further training with a small DES sample of galaxies (500-300), is enough for obtaining an accuracy > 95% and a significant improvement in the completeness and purity values. This demonstrates that, once trained with a particular dataset, machines can quickly adapt to new instrument characteristics (e.g., PSF, seeing, depth), reducing by almost one order of magnitude the necessary training sample for morphological classification. Redshift evolution effects or significant depth differences are not taken into account in this study.Peer reviewedFinal Accepted Versio
X(3872) and Other Possible Heavy Molecular States
We perform a systematic study of the possible molecular states composed of a
pair of heavy mesons such as , , in
the framework of the meson exchange model. The exchanged mesons include the
pseudoscalar, scalar and vector mesons. Through our investigation, we find that
(1) the structure X(3764) is not a molecular state; (2) There exists strong
attraction in the range fm for the system with .
If future experiments confirm as a loosely bound molecular state,
its quantum number is probably . Its partner state may
be searched for in the channel; (3) The vector meson exchange
provides strong attraction in the channel together with the
pion exchange. A bound state solution exists with a reasonable cutoff parameter
GeV. X(3872) may be accommodated as a molecular state
dynamically although drawing a very definite conclusion needs further
investigation; (4) The molecular state exists.Comment: 21 pages, 17 tables, 11 figures. Typos correcte
Configuration of anchorage holes affects fixation of the acetabular component in cemented total hip replacement - a finite element study
Our survey of current practice among UK orthopaedic surgeons shows wide variations in fixation techniques. The aim of this study is to investigate the effect of drilling different configurations of anchorage holes in the acetabulum on implant stability. To avoid variables that could incur during in-vitro testing, we used commercially-available COSMOS finite element analysis package to investigate the stress distributions, deformations, and strains on the cement mantle when drilling three large anchorage holes and six smaller ones, with straight and rounded cement pegs. The results, which are in line with our in-vitro studies on simulated reconstructed acetabulae, indicate better stability of the acetabular component when three larger holes than six smaller holes are drilled and when the necks of the anchorage holes are rounded. The longevity of total hip replacements could be improved by drilling three large anchorage holes, rather than many smaller ones, as initially proposed by Charnley
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