10,909 research outputs found

    Polyethylene imine-based receptor immobilization for label free bioassays

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    Polyethylene imine (PEI) based immobilization of antibodies is described and the concept is proved on the label free assay of C-Reactive Protein (CRP). This novel immobilization method is composed of a hyperbranched PEI layer which was deposited at a high pH (9.5) on the sensor surface. The free amino groups of PEI were derivatized with neutravidin by Biotin N-hydroxysuccinimide ester and the biotinylated anti-CRP antibody immobilized on this layer. Direct binding assay of recombinant CRP was successfully performed in the low ÎŒg/ml concentrations using a label free optical waveguide biosensor

    Characteristics of Feedback that Influence Student Confidence and Performance during Mathematical Modeling

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    This study focuses on characteristics of written feedback that influence students’ performance and confidence in addressing the mathematical complexity embedded in a Model-Eliciting Activity (MEA). MEAs are authentic mathematical modeling problems that facilitate students’ iterative development of solutions in a realistic context. We analyzed 132 first-year engineering students’ confidence levels and mathematical model scores on aMEA(pre and post feedback), along with teaching assistant feedback given to the students. The findings show several examples of affective and cognitive feedback that students reported that they used to revise their models. Students’ performance and confidence in developing mathematical models can be increased when they are in an environment where they iteratively develop models based on effective feedback

    Scaling Relations and Exponents in the Growth of Rough Interfaces Through Random Media

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    The growth of a rough interface through a random media is modelled by a continuous stochastic equation with a quenched noise. By use of the Novikov theorem we can transform the dependence of the noise on the interface height into an effective temporal correlation for different regimes of the evolution of the interface. The exponents characterizing the roughness of the interface can thus be computed by simple scaling arguments showing a good agreement with recent experiments and numerical simulations.Comment: 4 pages, RevTex, twocolumns, two figures (upon request). To appear in Europhysics Letter

    Color-flavor locked strange matter

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    We analyze how the CFL states in dense matter work in the direction of enhancing the parameter space for absolutely stable phases (strange matter). We find that the "CFL strange matter" phase can be the true ground state of hadronic matter for a much wider range of the parameters of the model (the gap of the QCD Cooper pairs Δ\Delta, the strange quark mass msm_s and the Bag Constant BB) than the state without any pairing, and derive a full equation of state and an accurate analytic approximation to the lowest order in Δ\Delta and msm_{s} which may be directly used for applications. The effects of pairing on the equation of state are found to be small (as previously expected) but not negligible and may be relevant for astrophysics.Comment: 5 pages, 2 figure

    “Basically... porn is everywhere”: a rapid evidence assessment on the effects that access and exposure to pornography has on children and young people

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    This Rapid Evidence Assessment (REA) was commissioned by the Office of the Children’s Commissioner (OCC) as part of its Inquiry into Child Sexual Exploitation in Gangs and Groups (CSEGG). It was conducted by a consortium led by Middlesex University, to explore the effects that exposure and access to pornography have on children and young people. The CSEGG Inquiry was launched in October 2011 to better understand the scale, scope, extent and nature of child sexual exploitation in gangs and groups. An emergent issue was whether accessing and viewing pornography can have an impact on children and young people’s expectations and attitudes towards sexual activity and relationships. Despite limited recourse to previous evidence, professionals interviewed over the course of the CSEGG Inquiry raised concerns about the impact of pornography at 43 per cent of site visits and 48 per cent of evidence hearings (Berelowitz et al., 2012). Professionals from many agencies reported particular concerns about the effects of pornography involving high levels of degradation, violence and humiliation, which they believe to be prevalent in material freely available online. Police case files that were reviewed cited instances of boys and young men referring to pornography during sexual assaults (Berelowitz et al., 2012). This REA was therefore commissioned to inform the CSEGG Inquiry Chair, Panel and Project Team, enabling them to add depth to their ultimate recommendations regarding child sexual exploitation in gangs and groups

    The Negativity of the Overlap-Based Topological Charge Density Correlator in Pure-Glue QCD and the Non-Integrable Nature of its Contact Part

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    We calculate the lattice two-point function of topological charge density in pure-glue QCD using the discretization of the operator based on the overlap Dirac matrix. Utilizing data at three lattice spacings it is shown that the continuum limit of the correlator complies with the requirement of non-positivity at non-zero distances. For our choice of the overlap operator and the Iwasaki gauge action we find that the size of the positive core is ~2a (with a being the lattice spacing) sufficiently close to the continuum limit. This result confirms that the overlap-based topological charge density is a valid local operator over realistic backgrounds contributing to the QCD path integral, and is important for the consistency of recent results indicating the existence of a low-dimensional global brane-like topological structure in the QCD vacuum. We also confirm the divergent short-distance behavior of the correlator, and the non-integrable nature of the associated contact part.Comment: 13 pages, 5 figure

    Overlap Valence on 2+1 Flavor Domain Wall Fermion Configurations with Deflation and Low-mode Substitution

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    The overlap fermion propagator is calculated on 2+1 flavor domain wall fermion gauge configurations on 16^3 x 32, 24^3 x 64 and 32^3 x 64 lattices. With HYP smearing and low eigenmode deflation, it is shown that the inversion of the overlap operator can be expedited by ~ 20 times for the 16^3 x 32 lattice and ~ 80 times for the 32^3 x 64 lattice. Through the study of hyperfine splitting, we found that the O(m^2a^2) error is small and these dynamical fermion lattices can adequately accommodate quark mass up to the charm quark. The low energy constant \Delta_{mix} which characterizes the discretization error of the pion made up of a pair of sea and valence quarks in this mixed action approach is calculated via the scalar correlator with periodic and anti-periodic boundary conditions. It is found to be small which shifts a 300 MeV pion mass by ~ 10 to 19 MeV on these sets of lattices. We have studied the signal-to-noise issue of the noise source for the meson and baryon. It is found that the many-to-all meson and baryon correlators with Z_3 grid source and low eigenmode substitution is efficient in reducing errors for the correlators of both mesons and baryons. With 64-point Z_3 grid source and low-mode substitution, it can reduce the statistical errors of the light quark (m_{\pi} ~ 200 - 300 MeV) meson and nucleon correlators by a factor of ~ 3-4 as compared to the point source. The Z_3 grid source itself can reduce the errors of the charmonium correlators by a factor of ~ 3.Comment: 30 pages, 18 figures, replaced with the version to be published in PR

    Nucleation of quark matter bubbles in neutron stars

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    The thermal nucleation of quark matter bubbles inside neutron stars is examined for various temperatures which the star may realistically encounter during its lifetime. It is found that for a bag constant less than a critical value, a very large part of the star will be converted into the quark phase within a fraction of a second. Depending on the equation of state for neutron star matter and strange quark matter, all or some of the outer parts of the star may subsequently be converted by a slower burning or a detonation.Comment: 13 pages, REVTeX, Phys.Rev.D (in press), IFA 93-32. 5 figures (not included) available upon request from [email protected]

    Treatment of benign prostatic hyperplasia by natural drugs

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    Benign prostatic hyperplasia (BPH) is one of the most common urinary diseases affecting men, generally after the age of 50. The prevalence of this multifactorial disease increases with age. With aging, the plasma level of testosterone decreases, as well as the testosterone/estrogen ratio, resulting in increased estrogen activity, which may facilitate the hyperplasia of the prostate cells. Another theory focuses on dihydrotestosterone (DHT) and the activity of the enzyme 5α-reductase, which converts testosterone to DHT. In older men, the activity of this enzyme increases, leading to a decreased testosterone/DHT ratio. DHT may promote prostate cell growth, resulting in hyperplasia. Some medicinal plants and their compounds act by modulating this enzyme, and have the above-mentioned targets. This review focuses on herbal drugs that are most widely used in the treatment of BPH, including pumpkin seed, willow herb, tomato, maritime pine bark, Pygeum africanum bark, rye pollen, saw palmetto fruit, and nettle root, highlighting the latest results of preclinical and clinical studies, as well as safety issues. In addition, the pharmaceutical care and other therapeutic options of BPH, including pharmacotherapy and surgical options, are discussed, summarizing and comparing the advantages and disadvantages of each therapy
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