1,753 research outputs found

    What is \u27equity\u27 in education

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    Equity in education is often viewed as equivalence or sameness. A more useful way to view equity is through the lens of ‘fairness’

    A doubled discretisation of abelian Chern-Simons theory

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    A new discretisation of a doubled, i.e. BF, version of the pure abelian Chern-Simons theory is presented. It reproduces the continuum expressions for the topological quantities of interest in the theory, namely the partition function and correlation function of Wilson loops. Similarities with free spinor field theory are discussed which are of interest in connection with lattice fermion doubling.Comment: 5 pages, revtex, 2 ps figures (epsf required). To appear in Phys.Rev.Let

    A geometric discretisation scheme applied to the Abelian Chern-Simons theory

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    We give a detailed general description of a recent geometrical discretisation scheme and illustrate, by explicit numerical calculation, the scheme's ability to capture topological features. The scheme is applied to the Abelian Chern-Simons theory and leads, after a necessary field doubling, to an expression for the discrete partition function in terms of untwisted Reidemeister torsion and of various triangulation dependent factors. The discrete partition function is evaluated computationally for various triangulations of S3S^3 and of lens spaces. The results confirm that the discretisation scheme is triangulation independent and coincides with the continuum partition functionComment: 27 pages, 5 figures, 6 tables. in late

    Applicability of Monte Carlo Glauber models to relativistic heavy ion collision data

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    The accuracy of Monte Carlo Glauber model descriptions of minimum-bias multiplicity frequency distributions is evaluated using data from the Relativistic Heavy Ion Collider (RHIC) within the context of a sensitive, power-law representation introduced previously by Trainor and Prindle (TP). Uncertainties in the Glauber model input and in the mid-rapidity multiplicity frequency distribution data are reviewed and estimated using the TP centrality methodology. The resulting errors in model-dependent geometrical quantities used to characterize heavy ion collisions ({\em i.e.} impact parameter, number of nucleon participants NpartN_{part}, number of binary interactions NbinN_{bin}, and average number of binary collisions per incident participant nucleon Μ\nu) are presented for minimum-bias Au-Au collisions at sNN\sqrt{s_{NN}} = 20, 62, 130 and 200 GeV and Cu-Cu collisions at sNN\sqrt{s_{NN}} = 62 and 200 GeV. Considerable improvement in the accuracy of collision geometry quantities is obtained compared to previous Monte Carlo Glauber model studies, confirming the TP conclusions. The present analysis provides a comprehensive list of the sources of uncertainty and the resulting errors in the above geometrical collision quantities as functions of centrality. The capability of energy deposition data from trigger detectors to enable further improvements in the accuracy of collision geometry quantities is also discussed.Comment: 27 pages, 4 figures, 11 table

    The Sum over Topologies in Three-Dimensional Euclidean Quantum Gravity

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    In Hawking's Euclidean path integral approach to quantum gravity, the partition function is computed by summing contributions from all possible topologies. The behavior such a sum can be estimated in three spacetime dimensions in the limit of small cosmological constant. The sum over topologies diverges for either sign of Λ\Lambda, but for dramatically different reasons: for Λ>0\Lambda>0, the divergent behavior comes from the contributions of very low volume, topologically complex manifolds, while for Λ<0\Lambda<0 it is a consequence of the existence of infinite sequences of relatively high volume manifolds with converging geometries. Possible implications for four-dimensional quantum gravity are discussed.Comment: 12 pages (LaTeX), UCD-92-1

    Massage Gun Use at a Lower Frequency Does Not Alter Blood Flow

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    Data has shown that whole body vibration can affect blood flow velocity in arteries and improves cutaneous blood flow. However, there is very limited information available on therapeutic localized vibration. Massage guns have become very popular with little to no research validating their efficacy. It is currently unknown if massages guns can affect arterial blood flow. PURPOSE: To determine if massage gun treatment at 30Hz improves and retains blood flow in the popliteal artery as compared to a control condition. METHODS: There were 12 participants in this study (8 males and 4 females). The mean age was 22.7±1.6 yrs, the mean height was 181.1± 11.8 cm, and the mean weight was 78.2±16.2 kg. Participants wore shorts that allowed us to access their popliteal artery using ultrasound imaging. Participants wore electrodes to control the measurement of blood flow from widest artery diameter. Participants lay prone with a foam roller under their ankles to slightly elevate their feet. After ten minutes of rest, ultrasound imaging was used to find the participant’s popliteal artery behind the knee and took two baseline measurements. We measured the mean velocity of blood flow (TAmean) and volume flow (VolF). We measured subjects on 4 different days (30Hz at 5 minutes, 30Hz 10 minutes, Control 5 minutes, Control 10 minutes). Measurements of TAmean and VolF were measured at multiple time points after treatment. RESULTS: A two-factor repeated measures analysis was performed. Each subject was measured under all levels of condition (1=30hz 5 min, 4=Control 5 mi, 5=30hz 10 min, 8=Control 10 min) and time (baseline, post, post1-5, 7, 9, 11, 13, 15, 17, 19). TA mean is significantly greater in 30Hz versus control (p=0.0349). TAmean varies across time, and the effect of the condition on TAmean is related to time (p=0.0104). There is not a significant difference in flow between 30Hz and control (p=0.2425). Blood flow varies across time (pCONCLUSION: Use of a massage gun at a lower frequency setting of 30Hz may cause slight increases in velocity but does not increase mean blood flow as compared to control. Lower frequency settings on massage guns may not be benefit blood flow in the massaged muscle group

    Stress‐response balance drives the evolution of a network module and its host genome

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    Stress response genes and their regulators form networks that underlie drug resistance. These networks often have an inherent tradeoff: their expression is costly in the absence of stress, but beneficial in stress. They can quickly emerge in the genomes of infectious microbes and cancer cells, protecting them from treatment. Yet, the evolution of stress resistance networks is not well understood. Here, we use a two‐component synthetic gene circuit integrated into the budding yeast genome to model experimentally the adaptation of a stress response module and its host genome in three different scenarios. In agreement with computational predictions, we find that: (i) intra‐module mutations target and eliminate the module if it confers only cost without any benefit to the cell; (ii) intra‐ and extra‐module mutations jointly activate the module if it is potentially beneficial and confers no cost; and (iii) a few specific mutations repeatedly fine‐tune the module's noisy response if it has excessive costs and/or insufficient benefits. Overall, these findings reveal how the timing and mechanisms of stress response network evolution depend on the environment

    Synthesis, Molecular Structure, and 1H NMR Analysis of Bis(tetraphenylcyclopentadienyl)ruthenium(II)

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    Reaction of [Ru(p-cymene)Cl2]2 with K(η5-C5HPh4) in refluxing diglyme yields (η5-C5Ph4)2Ru in ca 50% yield. The complex was not susceptible to oxidation or reduction. (C5HPH4)2Ru crystallizes in the triclinic P1 space group with a = 8.549(4), b = 10.793(4), c = 12.842(5) Å, α = 65.98(3), ÎČ = 73.10(3), Îł = 83.49(3)° and Z = 1. The least-squares data refined to R(F) = 3.53% and R(wF = 3.82% for the 3952 independent observed reflections with Fo ≄ 5σ(Fo). The metal-centroid distance is 1.832(2) Å and all other bond lengths and angles are similar to other octaphenylmetallocenes. 1H NMR analysis employing 2D J-resolved, COSY and low temperature techniques allowed assignment of all protons in the molecule. The motional processes of the phenyl groups are discussed

    Abundance and size distribution of permanent and temporary farm ponds in the southeastern Great Plains

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    Using aerial images from the US Department of Agriculture National Agriculture Imagery Program and the US Geological Survey National Hydrology Dataset, we estimated 577&thinsp;654 farm ponds with surface areas from 0.005 to 1 ha in a 229&thinsp;489 km2 region of the southeastern Great Plains (2.52 ponds/km2). Ponds with surface areas from 0.005 to 0.1 ha were the numerically dominant size class in the study region. The distribution of farm pond sizes followed an inverse power law relationship. We estimated 376&thinsp;209 permanent ponds and 201&thinsp;445 temporary ponds were in our study area. The ratio of temporary to permanent ponds within a pond size class was inversely related to pond surface area; 47% of ponds with surface areas of 0.005&ndash;0.1 ha were temporary, whereas only 13% of ponds with surface areas of 0.91&ndash;1 ha were temporary. Because permanent and temporary farm ponds are abundant and have different physicochemical properties and ecological communities, assessments of regional biogeochemical processes and biodiversity in the Great Plains must consider both types of ecosystems

    A Bound on the Superpotential

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    We prove a general bound on the superpotential in theories with broken supersymmetry and broken R-symmetry, 2|W|< f_a F, where f_a and F are the R-axion and Goldstino decay constants, respectively. The bound holds for weakly coupled as well as strongly coupled theories, thereby providing an exact result in theories with broken supersymmetry. We briefly discuss several possible applications.Comment: 20 page
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