Evidence of Program Quality and Youth Outcomes in the DYCD Out-of-School Time Initiative: Report on the Initiative's First Three Years

Examines New York City's progress in improving out-of-school-time program quality and serving more children and youth, participants' and parents' overall satisfaction with quality and accessibility, and links between programming, quality, and benefits

Diffusion mechanisms of localised knots along a polymer

We consider the diffusive motion of a localized knot along a linear polymer chain. In particular, we derive the mean diffusion time of the knot before it escapes from the chain once it gets close to one of the chain ends. Self-reptation of the entire chain between either end and the knot position, during which the knot is provided with free volume, leads to an L^3 scaling of diffusion time; for sufficiently long chains, subdiffusion will enhance this time even more. Conversely, we propose local ``breathing'', i.e., local conformational rearrangement inside the knot region (KR) and its immediate neighbourhood, as additional mechanism. The contribution of KR-breathing to the diffusion time scales only quadratically, L^2, speeding up the knot escape considerably and guaranteeing finite knot mobility even for very long chains.Comment: 7 pages, 2 figures. Accepted to Europhys. Let

Evaluation of the Beacon Community Centers Middle School Initiative: Report on the First Year

Evaluates the first year of an initiative to provide structured after-school and summer programs for fifth- through eighth-graders. Examines the centers' adaptation to the new focus, enrollment and participation levels, and implementation of core goals

Assessment of the environmental and economic performance of agroforestry along a European gradient

Poste

Improving After-School Program Quality

Summarizes the findings from two recent reports on afterschool programs and their implications for policy and practice. Supports the case that afterschool programs are capable of improving important youth outcomes

The Impacts of Dry Dynamic Cores on Asymmetric Hurricane Intensification

The article of record as published may be found at http://dx.doi.org/10.1175/JAS-D-16-0055.1The fundamental pathways for tropical cyclone (TC) intensification are explored by considering axisym- metric and asymmetric impulsive thermal perturbations to balanced, TC-like vortices using the dynamic cores of three different nonlinear numerical models. Attempts at reproducing the results of previous work, which used the community WRF Model, revealed a discrepancy with the impacts of purely asymmetric thermal forcing. The current study finds that thermal asymmetries can have an important, largely positive role on the vortex intensification, whereas other studies find that asymmetric impacts are negligible. Analysis of the spectral energetics of each numerical model indicates that the vortex response to asym- metric thermal perturbations is significantly damped in WRF relative to the other models. Spectral kinetic energy budgets show that this anomalous damping is primarily due to the increased removal of kinetic energy from the vertical divergence of the vertical pressure flux, which is related to the flux of inertia–gravity wave energy. The increased kinetic energy in the other two models is shown to originate around the scales of the heating and propagate upscale with time from nonlinear effects. For very large thermal amplitudes (50 K), the anomalous removal of kinetic energy due to inertia–gravity wave activity is much smaller, resulting in good agreement between models. The results of this paper indicate that the numerical treatment of small-scale processes that project strongly onto inertia–gravity wave energy can lead to significant differences in asymmetric TC intensification. Sensitivity tests with different time integration schemes suggest that diffusion entering into the implicit solution procedure is partly responsible for the anomalous damping of energy.Institute of Geophysics, Planetary Physics and Signatures (IGPPS) at Los Alamos National LaboratoryOffice of Naval Research through program element PE-0602435Institute of Geophysics, Planetary Physics and Signatures (IGPPS) at Los Alamos National LaboratoryOffice of Naval Research through program element PE-060243

Dye-sensitised semiconductors modified with molecular catalysts for light-driven H2 production.

The development of synthetic systems for the conversion of solar energy into chemical fuels is a research goal that continues to attract growing interest owing to its potential to provide renewable and storable energy in the form of a 'solar fuel'. Dye-sensitised photocatalysis (DSP) with molecular catalysts is a relatively new approach to convert sunlight into a fuel such as H2 and is based on the self-assembly of a molecular dye and electrocatalyst on a semiconductor nanoparticle. DSP systems combine advantages of both homogenous and heterogeneous photocatalysis, with the molecular components providing an excellent platform for tuning activity and understanding performance at defined catalytic sites, whereas the semiconductor bridge ensures favourable multi-electron transfer kinetics between the dye and the fuel-forming electrocatalyst. In this tutorial review, strategies and challenges for the assembly of functional molecular DSP systems and experimental techniques for their evaluation are explained. Current understanding of the factors governing electron transfer across inorganic-molecular interfaces is described and future directions and challenges for this field are outlined.This work was supported by the EPSRC (EP/H00338X/2 to E.R.; DTG scholarship to E.P.), the Christian Doppler Research Association (Austrian Federal Ministry of Science, Research and Economy and National Foundation for Research, Technology and Development; E.R. and J.W.), the OMV Group (E.R. and J.W.), the Advanced Institute for Materials ResearchCambridge Joint Research Centre (K.O.), European Commission Marie Curie CIG (303650 to A.R.) and the ERC (291482 to J.D.).This is the final version of the article. It was first available from RSC via http://dx.doi.org/10.1039/C5CS00733

Drivers of Macroinvertebrate Community Integrity Within Mixed Urban and Agricultural Dominated Mississippi Tributary Watersheds

The “urban stream syndrome” refers to a multitude of impacts caused by urbanization including flashier hydrograph, elevated concentrations of nutrients and contaminants, altered channel morphology and stability, reduced biotic richness, with increased dominance of tolerant species, reduced base flow and increased suspended solids. The drivers of these “symptoms” include impervious surfaces, piping in stormwater drainages, habitat and forest loss, water supply and sewer leaking, and direct alterations to channel morphology and flow. The goal of this study was to assess the integrity of the macroinvertebrate community and determine the most significant drivers of such integrity at the catchment, riparian zone, and reach scales. The study area included eight mixed land use (urban & agricultural) watersheds in Rock Island County, IL and Scott County, IA. Watersheds were delineated using Arc-GIS. Forty-one sampling sites were identified to capture the maximum variation in known drivers of watershed degradation. Macroinvertebrates were sampled using standard dip-netting techniques, with staples apportioned to different in-stream habitats weights by habitat abundance. Water quality data was collected monthly for the following parameters: total dissolved solids (TDS), total suspended solids (TSS) dissolved oxygen (DO), phosphate, and discharge. Sub-catchment basins above each sampling site were then delineated and used to quantify upstream landscape characteristics using available geospatial data including land cover, total impervious surface and within a 5m buffer of streams, etc. The family biotic index (FBI), a measure of integrity in relation to organic pollution tolerance was calculated

Solar H2_2 evolution in water with modified diketopyrrolopyrrole dyes immobilised on molecular Co and Ni catalyst–TiO2_2 hybrids

A series of diketopyrrolopyrrole (DPP) dyes with a terminal phosphonic acid group for attachment to metal oxide surfaces were synthesised and the effect of side chain modification on their properties investigated. The organic photosensitisers feature strong visible light absorption ($\lambda$ = 400 to 575 nm) and electrochemical and fluorescence studies revealed that the excited state of all dyes provides sufficient driving force for electron injection into the TiO$_2$ conduction band. The performance of the DPP chromophores attached to TiO$_2$ nanoparticles for photocatalytic H$_2$ evolution with co-immobilised molecular Co and Ni catalysts was subsequently studied, resulting in solar fuel generation with a dye-sensitised semiconductor nanoparticle system suspended in water without precious metal components. The performance of the DPP dyes in photocatalysis did not only depend on electronic parameters, but also on properties of the side chain such as polarity, steric hinderance and hydrophobicity as well as the specific experimental conditions and the nature of the sacrificial electron donor. In an aqueous pH 4.5 ascorbic acid solution with a phosphonated DuBois-type Ni catalyst, a DPP-based turnover number (TON$_{DPP}$) of up to 205 was obtained during UV-free simulated solar light irradiation (100 mW cm$^{-2}$ , AM 1.5G, $\lambda$ > 420 nm) after 1 day. DPP-sensitised TiO$_2$ nanoparticles were also successfully used in combination with a hydrogenase or platinum instead of the synthetic H$_2$ evolution catalysts and the platinum-based system achieved a TON$_{DPP}$ of up to 2660, which significantly outperforms an analogous system using a phosphonated Ru tris(bipyridine) dye (TON$_{Ru}$ = 431). Finally, transient absorption spectroscopy was performed to study interfacial recombination and dye regeneration kinetics revealing that the different performances of the DPP dyes are most likely dictated by the different regeneration efficiencies of the oxidised chromophores.Support by the Christian Doppler Research Association (Austrian Federal Ministry of Science, Research and Economy and National Foundation for Research, Technology and Development), the OMV Group and the Ministry of Education (Singapore) is gratefully acknowledged. RG is grateful to FRQNT for a Postdoctoral Fellowship and JRD thanks the European Science Foundation project Intersolar (291482) for support