8,658 research outputs found

    How to interpret the growing phenomenon of private tutoring : human capital deepening, inequality increasing, or waste of resources ?

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    Private tutoring is now a major component of the education sector in many developing countries, yet education policy too seldom acknowledges and makes use of it. Various criticisms have been raised against private tutoring, most notably that it exacerbates social inequalities and may even fail to improve student outcomes. This paper surveys the literature for evidence on private tutoring-the extent of the tutoring phenomenon, the factors that explain its growth, and its cost-effectiveness in improving student academic performance. It also presents a framework for assessing the efficiency and equity effects of tutoring. It concludes that tutoring can raise the effectiveness of the education system under certain reasonable assumptions, even taking into account equity concerns, and it offers guidance for attacking corruption and other problems that diminish the contributions of the tutoring sector.Teaching and Learning,Tertiary Education,Education For All,Primary Education,

    Results of bottom trawl surveys carried out in Vietnamese waters (20-200 m) in 1996-1997

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    Bottom trawl surveys were conducted in the southwest monsoon season in 1996 (survey 1) and in the northeast monsoon season in 1996-97 (survey 2) throughout Vietnamese waters. The surveys mainly covered the depth zone 50-200 m but in the northeast monsoon season the depth zone 20-50 m was included in the northern and southern areas. Overall, 273 trawl hauls were conducted. The total biomass for Vietnamese waters in the depth zone 20-200 m was estimated at 700 000 t . Biomass estimates are given for the most abundant species. A relatively higher mean catch-per-unit effort (CPUE) was obtained from survey 2 than from survey 1 and in partcular at depth ranges 50-100 and 100-200 m in south Vietnam. Overall, the dominant families were Monacanthidae (34%), Carangidae (15%), Trichiuridae (9%) and Synodontidae (6%)

    Pairing effect on the giant dipole resonance width at low temperature

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    The width of the giant dipole resonance (GDR) at finite temperature T in Sn-120 is calculated within the Phonon Damping Model including the neutron thermal pairing gap determined from the modified BCS theory. It is shown that the effect of thermal pairing causes a smaller GDR width at T below 2 MeV as compared to the one obtained neglecting pairing. This improves significantly the agreement between theory and experiment including the most recent data point at T = 1 MeV.Comment: 8 pages, 5 figures to be published in Physical Review

    Vacancy supersolid of hard-core bosons on the square lattice

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    The ground state of hard-core bosons on the square lattice with nearest and next-nearest neighbor repulsion is studied by Quantum Monte Carlo simulations. A supersolid phase with vacancy condensation and 'star' diagonal ordering is found for filling less than a quarter. At fillings above one quarter, a supersolid phase exists between the star and the stripe crystal at half-filling. No supersolid phase occurs above quarter-filling, if the ground state at half-filling is either a checkerboard crystal or a superfluid. No commensurate supersolid phase is observed.Comment: Replaced with published versio

    On "the authentic damping mechanism" of the phonon damping model

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    Some general features of the phonon damping model are presented. It is concluded that the fits performed within this model have no physical content

    Brown muscle disease and Manila clam Ruditapes Philippinarum dynamics in Arcachon Bay, France

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    Brown Muscle Disease (BMD) affects Manila clam Ruditapes philippinarum. It was described for the first time in 2005 in Arcachon Bay, France. The pathology consists in a progressive necrosis of the posterior adductor muscle, valve gaping, clam migration to the sediment surface, and death. This study aims to quantify the prevalence of BMD in the bay and to evaluate the effect of BMD on Manila clam dynamics. The prevalence was assessed on 50 stations spread within Arcachon Bay. About 62% of Manila clam habitat surface was infected by BMD. A survey of buried and surface clams was conducted from November 2006 to March 2008 in Lanton, a site infected by BMD. Modal progression analysis separated confidently cohorts from 2003 to 2005 recruitments. This pathology only affected adult clams (>25 mm, >2 years). For both buried and surface individuals, shell length was significantly correlated with BMD infection. Surface clams had prevalence (67%) higher than buried clams (23%) and showed greater mortality rate after 15 d in running water: 82% against 12% for buried individuals. The final disease index (FDI) and the condition index (CI) were monthly evaluated on 50 clams located at each position in the sediment. CI displayed a significant decrease after BMD's infection from light to severe disease stages. Length data analysis through Bhattacharya's method (FISAT II software) allowed identifying four cohorts. The 2003s cohort enabled to calculate mortality rate that was 39% for 5 months and to estimate that BMD was responsible of 95% of that mortality. The temperature was certainly an important factor in BMD transmission, because cohort dynamics results argued that BMD developed during spring and summer

    Damping of giant dipole resonance in hot rotating nuclei

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    The phonon damping model (PDM) is extended to include the effect of angular momentum at finite temperature. The model is applied to the study of damping of giant dipole resonance (GDR) in hot and noncollectively rotating spherical nuclei. The numerical results obtained for Mo88 and Sn106 show that the GDR width increases with both temperature T and angular momentum M. At T > 4 MeV and M<= 60 hbar the increase in the GDR width slows down for Sn106, whereas at M<= 80 hbar the GDR widths in both nuclei nearly saturate. By adopting the nuclear shear viscosity extracted from fission data at T= 0, it is shown that the maximal value of the angular momentum for Mo88 and Sn106 should be around 46 and 55 hbar, respectively, so that the universal conjecture for the lower bound of the specific shear viscosity for all fluids is not violated up to T= 5 MeV.Comment: 19 pages, 6 figures, accepted in Phys. Rev.
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