Providing True Opportunity for Opportunity Youth: Promising Practices and Principles for Helping Youth Facing Barriers to Employment

Many "opportunity youth" -- youth who are not working or in school -- would benefit substantially from gaining work experience but need help overcoming barriers to employment and accessing the labor market.Those opportunity youth facing the most significant challenges, such as extreme poverty, homelessness, and justice system involvement, often need even more intensive assistance in entering and keeping employment, and are at risk of being left behind even by employment programs that are specifically designed to serve opportunity youth.This paper builds on the research literature with extensive interviews with employment program providers who have had success in helping the most vulnerable opportunity youth succeed in the workforce. Six principles for effectively serving these youth are identified

Accumulation layer profiles at InAs polar surfaces

High resolution electron energy loss spectroscopy, dielectric theory simulations, and charge profile calculations have been used to study the accumulation layer and surface plasmon excitations at the In-terminated (001)-(4 × 1) and (111)A-(2 × 2) surfaces of InAs. For the (001) surface, the surface state density is 4.0 ± 2.0 × 1011 cm – 2, while for the (111)A surface it is 7.5 ± 2.0 × 1011 cm – 2, these values being independent of the surface preparation procedure, bulk doping level, and substrate temperature. Changes of the bulk Fermi level with temperature and bulk doping level do, however, alter the position of the surface Fermi level. Ion bombardment and annealing of the surface affect the accumulation layer only through changes in the effective bulk doping level and the bulk momentum scattering rate, with no discernible changes in the surface charge density

Segmented waveguides in thin silicon-on-insulator

We have developed new silicon-on-insulator waveguide designs for simultaneously achieving both low-loss optical confinement and electrical contacts, and we present a design methodology based on calculating the Bloch modes of such segmented waveguides. With this formalism, waveguides are designed in a single thin layer of silicon-on-insulator to achieve both optical confinement and minimal insertion loss. Waveguides were also fabricated and tested, and the measured data were found to closely agree with theoretical predictions, demonstrating input insertion loss and propagation loss better than 0.1 dB and -16 dB/cm, respectively

The Butcher-Oemler Effect in High Redshift X-ray Selected Clusters

We are engaged in a wide-field, multi-colour imaging survey of X-ray selected clusters at intermediate and high redshift. We present blue fractions for the first 8 out of 29 clusters, covering almost a factor of 100 in X-ray luminosity. We find no correlation of blue fraction with redshift or X-ray luminosity. The lack of a correlation with L$_{X}$, places strong constraints on the importance of ram-pressure stripping as a driver of the Butcher-Oemler effect.Comment: 4 pages, 4 figures, to be puplished in the proceedings of the ''Sesto 2001-Tracing Cosmic Evolution with Galaxy Clusters'', Sesto 3-6 July 2001, Italy, eds, Stefano Borgan

High eccentricity planets from the Anglo-Australian Planet Search

We report Doppler measurements of the stars HD187085 and HD20782 which indicate two high eccentricity low-mass companions to the stars. We find HD187085 has a Jupiter-mass companion with a ~1000d orbit. Our formal `best fit' solution suggests an eccentricity of 0.47, however, it does not sample the periastron passage of the companion and we find that orbital solutions with eccentricities between 0.1 and 0.8 give only slightly poorer fits (based on RMS and chi^2) and are thus plausible. Observations made during periastron passage in 2007 June should allow for the reliable determination of the orbital eccentricity for the companion to HD187085. Our dataset for HD20782 does sample periastron and so the orbit for its companion can be more reliably determined. We find the companion to HD20782 has M sin i=1.77+/-0.22M_JUP, an orbital period of 595.86+/-0.03d and an orbit with an eccentricity of 0.92+/-0.03. The detection of such high-eccentricity (and relatively low velocity amplitude) exoplanets appears to be facilitated by the long-term precision of the Anglo-Australian Planet Search. Looking at exoplanet detections as a whole, we find that those with higher eccentricity seem to have relatively higher velocity amplitudes indicating higher mass planets and/or an observational bias against the detection of high eccentricity systems.Comment: to appear in MNRA

The development of a new generation of methyl chloride synthesis catalyst

In previous work by the authors, aspects of the surface chemistry connected with methyl chloride synthesis over an -alumina catalyst have been examined. This communication considers a role for Group 1 metal salts to modify the catalytic performance of the well characterised -alumina catalyst. Firstly, based on a previously postulated mechanism for the reaction of methanol on -alumina, a mechanism for methyl chloride synthesis over the -alumina catalyst is proposed. Secondly, the validity of the new mechanism is tested by observing how the (i) type and (ii) loading of the Group 1 metal salt may perturb methyl chloride selectivity. The outcomes of these measurements are rationalised with reference to the postulated mechanism. Overall, this study represents an example of how a proposed reaction mechanism has been used to inform and guide a catalyst development strategy for a large-scale industrial process

The environmental dependence of galaxy colors in intermediate-redshift X‐ray–selected clusters

We present a wide-field imaging study of the colors of bright galaxies (∗ + 2) in a sample of 12 X-ray–selected clusters and groups of galaxies at z ~ 0:3. The systems cover one of the largest ranges in X-ray luminosity (Lx ~ 1043 1045 ergs s-1), and hence mass, of any sample studied at this redshift. We find that the ‘‘red’’ galaxies form a tight color-magnitude relation (CMR) and that neither the slope nor zero point of this relation changes significantly over the factor of 100 in X-ray luminosity covered by our sample. Using stellar population synthesis models, we find that our data allow a maximum possible change of 2 Gyr in the typical age of the ‘‘red’’ galaxies on the CMR over the range of Lx of our sample.We also measure the fraction of blue galaxies (fb) relative to the CMR in our clusters and find a low value of fb ~ 0.1 consistent with other X-ray–selected cluster samples.We find that there is no correlation between fb and Lx over our large Lx range. However, we do find that both the CMR and fb depend significantly on cluster radius, with the zero point of the CMR shifting blueward in B - R by 0.10 ± 0.036 mag out to a radius of 0.75 times the virial radius. This color change is equivalent to a luminosity-weighted age gradient of ~2.5 Gyr per log (radius) and is consistent with previous studies of the radial change in the zero point of the CMR. It thus appears that the global cluster environment, in the form of cluster mass (Lx), has little influence on the properties of the bright cluster galaxies, whereas the local environment, in the form of galaxy density (radius), has a strong effect. The range of ~100 in Lx corresponds to a factor of ~40 in ram pressure efficiency, thus suggesting that ram pressure stripping or other mechanisms that depend on cluster mass, like tidal stripping or harassment, are unlikely to be solely responsible for changing the galaxy population from the ‘‘blue’’ star-forming galaxies, which dominate low-density environments, to the ‘‘red’’ passive galaxies, which dominate cluster cores