928 research outputs found

    Family characteristics, students' reading habits, environment and students' academic performance in Nigeria

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    The paper examined family background factors that affect students' academic achievement in institutions of higher learning in Nigeria. With the use of structured questionnaire, data were collected from 110 first-degree final year students using random sampling and analysed through multiple linear regression techniques. It was found that student's academic performance was positively influenced by student's parental level of education, maternal income level, age, income of the student and number of hours allocated for reading on daily basis. Those students who spent more hours reading their books daily were found performing better than those who spent lesser hours. The hypothesis that parental educational level impacted positive effects on students' academic performance was confirmed valid for the country while effects of parental occupation and parental income were mixed. The major finding of the paper was that higher educational attainment and income status of parents were essential factors contributing to high academic record of students of tertiary institutions. It was, therefore, recommended that policy that enforces higher education advancement for all parents should be enforced in Nigeria

    Accommodative-Convergence Mechanism failure in HIV-Positive Non Presbyopic Patient on Highly Active Anti-Retroviral Therapy: A case report

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    Purpose: Accommodative-convergence mechanism failure could occur in non presbyopic HIV- sero positive patients on Highly Active Anti-Retroviral  Therapy (HAART). This could be due to either direct neuronal infection by HIV, pathologic changes of the lens or the ciliary body or adverse effects of some individual drugs constituting the HAART regimen on the cranial nerves which play vital roles in the mechanism of accommodation and convergence. Case report: This is a case report of an accommodative- convergence mechanism failure in HIV positive non presbyopic 32-year-old male patient  that was on HAART for more than five years. He presented with distance visual acuity (VA) of OD: 6/9 +2, OS: 6/9, and near visual acuity (NVA) of N24 both eyes, 3Δ esophoria at distance and 4Δ esophoria at near. Amplitude of accommodation (AA) was 3.50D and accommodative  convergence/accommodation (AC/A) ratio was 6/1. Following comprehensive evaluation, his refractive correction was OD: Plano/-0.50DC X 180 6/5 and OS: Plano/-0.50DC X 90 6/5 at distance with near addition (Add) 2.50D N5. This was prescribed for regular wear in form of D-Top bifocal lens. Conclusion: These findings showed that HIV sero-positive adults on HAART could develop accommodativeconvergence mechanism failure, which may be characterized by low amplitude of accommodation, receded near point of convergence and high non presbyopic reading addition. These conditions may be under-recognized and need for reading addition of a non presbyopic age is often overlooked. Key Words: Accommodative-Convergence, HIV, Lateral Phoria, Refractive error

    Power losses in thick steel laminations with hysteresis

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    Magnetic power losses have been experimentally investigated and theoretically predicted over a range of frequencies (direct current—1.5 kHz) and peak inductions (0.5-1.5 T) in 1‐mm‐thick FeSi 2 wt. % laminations. The direct current hysteresis properties of the system are described by the Preisach model, with the Preisach distribution function reconstructed from the measurement of the recoil magnetization curve (Bp=1.7 T). On this basis, the time behavior of the magnetic induction vs frequency at different lamination depths is calculated by a finite element method numerical solution of Maxwell equations, which takes explicitly into account the Preisach model hysteretic B(H) relationship. The computed loop shapes are, in general, in good agreement with the measured ones. The power loss dependence on frequency is predicted and experimentally found to change from a ∼f3/2 to a ∼f2 law with increasing peak induction

    Quasi-One-Dimensional Spin Dynamics in dd-Electron Heavy-Fermion Metal Y1x_{1-x}Scx_xMn2_2

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    Slow spin fluctuations (ν<1012\nu < 10^{12} s1^-1) observed by the muon spin relaxation technique in Y1x_{1-x}Scx_xMn2_2 exhibits a power law dependence on temperature (νTα\nu \propto T^\alpha), where the power converges asymptotically to unity (α1\alpha\rightarrow 1) as the system moves away from spin-glass instability with increasing Sc content xx. This linear TT dependence, which is common to that observed in LiV2_2O4_4, is in line with the prediction of the "intersecting Hubbard chains" model for a metallic pyrochlore lattice, suggesting that the geometrical constraints to t2g bands specific to the pyrochlore structure serve as a basis of the dd-electron heavy-fermion state.Comment: 5 pages, 4 figures, to appear in J. Phys. Soc. Jp

    Are Mandates the Answer? Improving Palliative Care and Pain Management in Vermont

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    Background: The Vermont legislature (bill H.435, Sec. 19) has tasked the Vermont Board of Medical Practice (VBMP) with making a formal recommendation on improving Vermont health professionals’ knowledge and practice of Palliative Care and Pain Management (PC/PM). In collaboration with the VBMP, our group set out to answer the following questions: • How confident/competent are VT physicians in the practice of PC/PM? • What are the barriers to achieving optimal patient care in PC/PM? • Do VT physicians believe mandatory CME would improve the overall quality of care in PC/PM? • What are the best methods of providing Continuing Medical Education (CME)?https://scholarworks.uvm.edu/comphp_gallery/1040/thumbnail.jp

    Left gaze bias in humans, rhesus monkeys and domestic dogs

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    While viewing faces, human adults often demonstrate a natural gaze bias towards the left visual field, that is, the right side of the viewee’s face is often inspected first and for longer periods. Using a preferential looking paradigm, we demonstrate that this bias is neither uniquely human nor limited to primates, and provide evidence to help elucidate its biological function within a broader social cognitive framework. We observed that 6-month-old infants showed a wider tendency for left gaze preference towards objects and faces of different species and orientation, while in adults the bias appears only towards upright human faces. Rhesus monkeys showed a left gaze bias towards upright human and monkey faces, but not towards inverted faces. Domestic dogs, however, only demonstrated a left gaze bias towards human faces, but not towards monkey or dog faces, nor to inanimate object images. Our findings suggest that face- and species-sensitive gaze asymmetry is more widespread in the animal kingdom than previously recognised, is not constrained by attentional or scanning bias, and could be shaped by experience to develop adaptive behavioural significance

    Time resolution of the plastic scintillator strips with matrix photomultiplier readout for J-PET tomograph

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    Recent tests of a single module of the Jagiellonian Positron Emission Tomography system (J-PET) consisting of 30 cm long plastic scintillator strips have proven its applicability for the detection of annihilation quanta (0.511 MeV) with a coincidence resolving time (CRT) of 0.266 ns. The achieved resolution is almost by a factor of two better with respect to the current TOF-PET detectors and it can still be improved since, as it is shown in this article, the intrinsic limit of time resolution for the determination of time of the interaction of 0.511 MeV gamma quanta in plastic scintillators is much lower. As the major point of the article, a method allowing to record timestamps of several photons, at two ends of the scintillator strip, by means of matrix of silicon photomultipliers (SiPM) is introduced. As a result of simulations, conducted with the number of SiPM varying from 4 to 42, it is shown that the improvement of timing resolution saturates with the growing number of photomultipliers, and that the 2 x 5 configuration at two ends allowing to read twenty timestamps, constitutes an optimal solution. The conducted simulations accounted for the emission time distribution, photon transport and absorption inside the scintillator, as well as quantum efficiency and transit time spread of photosensors, and were checked based on the experimental results. Application of the 2 x 5 matrix of SiPM allows for achieving the coincidence resolving time in positron emission tomography of \approx 0.170 ns for 15 cm axial field-of-view (AFOV) and \approx 0.365 ns for 100 cm AFOV. The results open perspectives for construction of a cost-effective TOF-PET scanner with significantly better TOF resolution and larger AFOV with respect to the current TOF-PET modalities.Comment: To be published in Phys. Med. Biol. (26 pages, 17 figures

    Muon capture by 3He nuclei followed by proton and deuteron production

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    The paper describes an experiment aimed at studying muon capture by 3He{}^{3}\mathrm{He} nuclei in pure 3He{}^{3}\mathrm{He} and D2+3He\mathrm{D}_2 + {}^{3}\mathrm{He} mixtures at various densities. Energy distributions of protons and deuterons produced via μ+3Hep+n+n+νμ\mu^-+{}^{3}\mathrm{He}\to p+n+n + \nu_{\mu } and μ+3Hed+n+νμ\mu^-+{}^{3} \mathrm{He} \to d+n + \nu_{\mu} are measured for the energy intervals 104910 - 49 MeV and 133113 - 31 MeV, respectively. Muon capture rates, λcapp(ΔEp)\lambda_\mathrm{cap}^p (\Delta E_p) and λcapd(ΔEd)\lambda_\mathrm{cap}^d (\Delta E_d) are obtained using two different analysis methods. The least--squares methods gives λcapp=(36.7±1.2)s1\lambda_\mathrm{cap}^p = (36.7\pm 1.2) {s}^{- 1}, λcapd=(21.3±1.6)s1\lambda_\mathrm{cap}^d = (21.3 \pm 1.6) {s}^{- 1}. The Bayes theorem gives λcapp=(36.8±0.8)s1\lambda_\mathrm{cap}^p = (36.8 \pm 0.8) {s}^{- 1}, λcapd=(21.9±0.6)s1\lambda_\mathrm{cap}^d = (21.9 \pm 0.6) {s}^{- 1}. The experimental differential capture rates, dλcapp(Ep)/dEpd\lambda_\mathrm{cap}^p (E_p) / dE_p and dλcapd(Ed)/dEd d\lambda_\mathrm{cap}^d (E_d) / dE_d, are compared with theoretical calculations performed using the plane--wave impulse approximation (PWIA) with the realistic NN interaction Bonn B potential. Extrapolation to the full energy range yields total proton and deuteron capture rates in good agreement with former results.Comment: 17 pages, 13 figures, accepted for publication in PR

    Measurement of the Polarized Structure Function σLT\sigma_{LT^\prime} for p(e,eπ+)np(\vec{e},e'\pi^+)n in the Δ(1232)\Delta(1232) Resonance Region

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    The polarized longitudinal-transverse structure function σLT\sigma_{LT^\prime} has been measured using the p(e,eπ+)np(\vec e,e'\pi^+)n reaction in the Δ(1232)\Delta(1232) resonance region at Q2=0.40Q^2=0.40 and 0.65 GeV2^2. No previous σLT\sigma_{LT^\prime} data exist for this reaction channel. The kinematically complete experiment was performed at Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS) using longitudinally polarized electrons at an energy of 1.515 GeV. A partial wave analysis of the data shows generally better agreement with recent phenomenological models of pion electroproduction compared to the previously measured π0p\pi^0 p channel. A fit to both π0p\pi^0 p and π+n\pi^+ n channels using a unitary isobar model suggests the unitarized Born terms provide a consistent description of the non-resonant background. The tt-channel pion pole term is important in the π0p\pi^0 p channel through a rescattering correction, which could be model-dependent.Comment: 6 pages, LaTex, 5 eps figures: Submitted to PRC/Brief Reports v2: Updated referenc
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