A Weak Gravitational Lensing Analysis of Abell 2390

We report on the detection of dark matter in the cluster Abell 2390 using the weak gravitational distortion of background galaxies. We find that the cluster light and total mass distributions are quite similar over an angular scale of \simeq 7^\prime \;(1 \Mpc). The cluster galaxy and mass distributions are centered on the cluster cD galaxy and exhibit elliptical isocontours in the central \simeq 2^\prime \; (280 \kpc). The major axis of the ellipticity is aligned with the direction defined by the cluster cD and a ``straight arc'' located $\simeq 38^{\prime\prime}$ to the northwest. We determined the radial mass-to-light profile for this cluster and found a constant value of $(320 \pm 90) h\; M_\odot/L_{\odot V}$, which is consistent with other published determinations. We also compared our weak lensing azimuthally averaged radial mass profile with a spherical mass model proposed by the CNOC group on the basis of their detailed dynamical study of the cluster. We find good agreement between the two profiles, although there are weak indications that the CNOC density profile may be falling more steeply for $\theta\geq 3^\prime$ (420\kpc).Comment: 14 pages, latex file. Postscript file and one additional figure are available at ftp://magicbean.berkeley.edu/pub/squires/a2390/massandlight.ps.g

Magnetic spectrum of the two-dimensional antiferromagnet La2CoO4 studied by inelastic neutron scattering

We report measurements of the magnetic excitation spectrum of the layered antiferromagnet La2CoO4 by time-of-flight neutron inelastic scattering. In the energy range probed in our experiments (0-250 meV) the magnetic spectrum consists of spin-wave modes with strong in-plane dispersion extending up to 60 meV, and a nearly dispersionless peak at 190 meV. The spin-wave modes exhibit a small (~1 meV) dispersion along the magnetic zone boundary. We show that the magnetic spectrum can be described very well by a model of a Heisenberg antiferromagnet that includes the full spin and orbital degrees of freedom of Co2+ in an axially-distorted crystal field. The collective magnetic dynamics are found to be controlled by dominant nearest-neighbour exchange interactions, strong XY-like single-ion anisotropy and a substantial unquenched orbital angular momentum.Comment: 8 pages, 7 figure

Investigating heuristic evaluation as a methodology for evaluating pedagogical software: An analysis employing three case studies

This paper looks specifically at how to develop light weight methods of evaluating pedagogically motivated software. Whilst we value traditional usability testing methods this paper will look at how Heuristic Evaluation can be used as both a driving force of Software Engineering Iterative Refinement and end of project Evaluation. We present three case studies in the area of Pedagogical Software and show how we have used this technique in a variety of ways. The paper presents results and reflections on what we have learned. We conclude with a discussion on how this technique might inform on the latest developments on delivery of distance learning. © 2014 Springer International Publishing

Access to Capital: Milwaukee's Continuing Small Business Lending Gaps

This study provides a detailed review of small business lending in Milwaukee, Wisconsin and illustrates how this new data set can be utilized to assess small business lending in virtually any local market. Milwaukee is a fairly typical industrial community that has been hit hard by decades of disinvestment but which also has been the location of many successful community reinvestment initiatives in recent years (Squires and O'Connor 2001). Previous research found that among the nation's fifty largest metropolitan areas Milwaukee had the smallest share of small business loans going to low- and moderate-income areas (Norman 1998). Lending to small businesses, that is firms with assets below $1 million, was also found to be below nationwide levels. Small business lending has also been concentrated in white communities with black and Hispanic communities receiving relatively small shares of such loans and loan dollars. But lenders vary dramatically in Milwaukee in terms of the distribution of their small business loans by neighborhood income level (Squires and O'Connor 1999). This study examines changes in small business lending patterns in Milwaukee between 1996, when these data first became available, and 1999, the most recent data that are available

Motivational interviewing. A guideline developed for the Behavioral Health Recovery Management project.

A guideline providing introductory understanding of the basic principles of motivational interviewing (MI). MI should not be thought of as a programmed, point-by-point treatment approach, but as a diffuse style of clinical interaction employing four primary principles