9,755 research outputs found

    The Harlem Children's Zone, Promise Neighborhoods, and the Broader, Bolder Approach to Education

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    Examines the role of community services in raising academic achievement in the Harlem Children's Zone. Questions the effectiveness of replicating the neighborhood approach, rather than the schools-only approach, in the Promise Neighborhoods Initiative

    Comparing the penetrative stab performance of the UK HOSDB P1/B and Stanley Tools 1992 trimming blades on certified body armour specimens

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    This body of research assessed the penetrative stab performance of the United Kingdom Home Office Scientific Development Branch’s (HOSDB) P1/B certified blades against the readily accessible Stanley Tools 1992 trimming blade. All tests were performed against the HOSDB KR1-E1 impact energy of 24 Joules on HOSDB KR1 certified body armour specimens. Results demonstrated that the Stanley 1992 trimming blade posed a 30% greater stab threat in comparison to the HOSDB P1/B blade. This paper demonstrates the threat imposed by readily available utility blades and a requirement to enhance existing body stab resistant body armour test procedures testing procedures

    Fees and Surcharging in automatic teller machine networks: Non-bank ATM providers versus large banks

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    This paper develops a spacial model of ATM networks to explore the implications for banks and non-banks of interchange fees, foreign fees and surcharges applied to transactions by customers at other than an own-bank ATM. Surcharging raises the price (foreign fee plus surcharge) paid by customers above the joint profit-maximizing level achieved by setting the interchange fee at marginal cost and not surcharging. Similar size banks would agree not to surcharge, but such an agreement is typically not possible between a bank and a non-bank. A high cost of teller transactions modifies the tendency towards high ATM fees.

    Lyman-alpha forest-CMB cross-correlation and the search for the ionized baryons at high redshift

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    The intergalactic neutral hydrogen which is responsible for the Lyman alpha forest of quasar absorption is a tracer of much larger amounts of ionised hydrogen. The ionised component has yet to be detected directly, but is expected to scatter CMB photons via the Sunyaev-Zel'dovich (SZ) effect. We use hydrodynamic simulations of a LambdaCDM universe to create mock quasar spectra and CMB sky maps. We find that the high-z Lya forest gas causes temperature fluctuations of the order of 1 muK rms in the CMB on arcmin scales. The kinetic and thermal SZ effects have a similar magnitude at z=3, with the thermal effect becoming relatively weaker as expected at higher z. The CMB signal associated with lines of sight having HI column densities > 10^18 cm^-2 is only marginally stronger than that for lower column densities. The strong dependence of rms temperature fluctuation on mean Lya absorbed flux, however, suggests that the CMB signal effectively arises in lower density material. We investigate the use of the cross-correlation of the Lya forest and the microwave background to detect the SZ effect at redshifts 2-4. In so doing we are able to set direct limits on the density of diffuse ionised intergalactic baryons. We carry out a preliminary comparison at a mean redshift z=3 of 3488 quasar spectra from SDSS Data Release 3 and the WMAP first year data. Assuming that the baryons are clustered as in a LambdaCDM cosmology, and have the same mean temperature, the cross-correlation yields a weak limit on the cosmic density of ionised baryons Omega_(b,I), which is Omega_(b,I) < 0.8 at 95% confidence. With data from upcoming CMB telescopes, we anticipate that a direct detection of the high redshift ionised IGM will soon be possible, providing an important consistency check on cosmological models.Comment: 14 pages, 10 figures, submitted to MNRA
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