The Globular Cluster Luminosity Function and Specific Frequency in Dwarf Elliptical Galaxies

The globular cluster luminosity function, specific globular cluster frequency, S_N, specific globular cluster mass, T_MP, and globular cluster mass fraction in dwarf elliptical galaxies are explored using the full 69 galaxy sample of the HST WFPC2 Dwarf Elliptical Galaxy Snapshot Survey. The GCLFs of the dEs are well-represented with a t_5 function with a peak at M_{V,Z}^0(dE,HST) = -7.3 +/- 0.1. This is ~0.3 magnitudes fainter than the GCLF peaks in giant spiral and elliptical galaxies, but the results are consistent within the uncertainties. The bright-end slope of the luminosity distribution has a power-law form with slope alpha = -1.9 +/- 0.1. The trend of increasing S_N or T_MP with decreasing host galaxy luminosity is confirmed. The mean value for T_MP in dE,N galaxies is about a factor of two higher than the mean value for non-nucleated galaxies and the distributions of T_MP in dE,N and dE,noN galaxies are statistically different. These data are combined with results from the literature for a wide range of galaxy types and environments. At low host galaxy masses the distribution of T_MP for dE,noN and dI galaxies are similar. This supports the idea that one pathway for forming dE,noN galaxies is by the stripping of dIs. The formation of nuclei and the larger values of T_MP in dE,N galaxies may be due to higher star formation rates and star cluster formation efficiencies due to interactions in galaxy cluster environments.Comment: 53 pages, 13 figures, 12 tables, accepted by the Astrophysical Journa

Coping with a Limited Capacity to Punish: A Replication

This project replicated a study by Farnworth, Golden and Tester in 1991 to determine if alternate sentencing practices, such as charge reductions and probation, were being used to decrease prison populations and lessen the burden on the criminal justice system as a whole. The previous article sought to support earlier findings that asserted that prison overcrowding caused an increase in the use of charge reductions and felony convictions, but found this to be untrue [1]. They actually found decreased use of charge reductions during the decade under study even as the prison population continued to rise. The current study analyzed data during the period of 1990 to 1999 from Pulaski County, Arkansas in the context of Pontell’s [2] concept of “a limited capacity to punish.” The Arkansas data analyzed also demonstrated a decrease in charge reductions as the prison population for the state grew thus supporting the previous research on the topic

Preservice teachers’ pictorial strategies for a multistep multiplicative fraction problem

Previous research has documented that preservice teachers (PSTs) struggle with under- standing fraction concepts and operations, and misconceptions often stem from their understanding of the referent whole. This study expands research on PSTs’ understanding of wholes by investigating pictorial strategies that 85 PSTs constructed for a multistep fraction task in a multiplicative context. The results show that many PSTs were able to construct valid pictorial strategies, and the strategies were widely diverse with respect to how they made sense of an unknown referent whole of a fraction in multiple steps, how they represented the wholes in their drawings, in which order they did multiple steps, and which type of model they used (area or set). Based on their wide range of pictorial strategies, we discuss potential benefits of PSTs’ construction of their own representations for a word problem in developing problem solving skills

Star Clusters in Virgo and Fornax Dwarf Irregular Galaxies

We present the results of a search for clusters in dwarf irregular galaxies in the Virgo and Fornax Cluster using HST WFPC2 snapshot data. The galaxy sample includes 28 galaxies, 11 of which are confirmed members of the Virgo and Fornax clusters. In the 11 confirmed members, we detect 237 cluster candidates and determine their V magnitudes, V-I colors and core radii. After statistical subtraction of background galaxies and foreground stars, most of the cluster candidates have V-I colors of -0.2 and 1.4, V magnitudes lying between 20 and 25th magnitude and core radii between 0 and 6 pc. Using H-alpha observations, we find that 26% of the blue cluster candidates are most likely HII regions. The rest of the cluster candidates are most likely massive (>10^4 Msol) young and old clusters. A comparison between the red cluster candidates in our sample and the Milky Way globular clusters shows that they have similar luminosity distributions, but that the red cluster candidates typically have larger core radii. Assuming that the red cluster candidates are in fact globular clusters, we derive specific frequencies (S_N) ranging from ~0-9 for the galaxies. Although the values are uncertain, seven of the galaxies appear to have specific frequencies greater than 2. These values are more typical of ellipticals and nucleated dwarf ellipticals than they are of spirals or Local Group dwarf irregulars.Comment: 46 pages, 14 figures, 3 tables, accepted by AJ. Higher quality PS version of entire paper available at http://www.astro.washington.edu/seth/dirr_gcs.htm

The Specific Globular Cluster Frequencies of Dwarf Elliptical Galaxies from the Hubble Space Telescope

The specific globular cluster frequencies (S_N) for 24 dwarf elliptical (dE) galaxies in the Virgo and Fornax Clusters and the Leo Group imaged with the Hubble Space Telescope are presented. Combining all available data, we find that for nucleated dEs --- which are spatially distributed like giant ellipticals in galaxy clusters --- S_N(dE,N)=6.5 +- 1.2 and S_N increases with M_V, while for non-nucleated dEs --- which are distributed like late-type galaxies --- S_N(dE,noN)=3.1 +- 0.5 and there is little or no trend with M_V. The S_N values for dE galaxies are thus on average significantly higher than those for late-type galaxies, which have S_N < 1. This suggests that dE galaxies are more akin to giant Es than to late-type galaxies. If there are dormant or stripped irregulars hiding among the dE population, they are likely to be among the non-nucleated dEs. Furthermore, the similarities in the properties of the globular clusters and in the spatial distributions of dE,Ns and giant Es suggest that neither galaxy mass or galaxy metallicity is responsible for high values of S_N. Instead, most metal-poor GCs may have formed in dwarf-sized fragments that merged into larger galaxies.Comment: 12 pages (uses aaspp4.sty), 2 figures, 1 table, to appear in the Astrophysical Journa

Cognitive Appraisals, Coping and Depressive Symptoms in Breast Cancer Patients

Depression in breast cancer patients and survivors is related to negative disease outcomes and worse quality of life. Factors that explain this depression can serve as targets of intervention. This study, guided by the Transactional Theory of Stress, examined the relationship between cognitive appraisals, coping strategies and depressive symptoms in a group of women with mostly advanced-stage breast cancer (N = 65), who scored mostly within the normal range for depressive symptoms. Path analysis was used to determine the relationships among variables, measured with the Cognitive Appraisals of Illness Scale, the Ways of Coping Questionnaire and the Center for Epidemiological Studies Depression Scale. The results of the path analysis showed that higher appraisals of harm/loss and greater use of escape–avoidance coping predicted higher depressive symptoms. These findings enhance the prediction of depression among breast cancer patients and suggest the need to examine cognitive appraisals when attempting to understand depressive symptoms

An Examination of Crime Perception and Arkansas Fair Housing

This study examines the issue of fair housing from the standpoint of appraisal reports that determine the value of properties. Specifically, descriptors of crime within Arkansas appraisal reports are analyzed, along with completed interview questionnaires representing the mortgage lending, law enforcement, and home appraisal communities. This study provides pivotal findings with respect to appraisal reports in Arkansas and implications for public policy. Particularly, it finds that some of the most relevant stakeholders related to housing in Arkansas unfairly categorize certain geographic areas according to perceptions of crime, as indicated by a review of data found within appraisal reports. This study has implications for sales, rentals, and mortgage lending within the entire state of Arkansas; it also illustrates perpetuated stereotypes about specific groups of people. Finally, a significant policy recommendation is offered by this collaborative research

Why We Are Here: A Review of the Literature on Motivations for Postdoctoral Appointments

Abstract: This paper reviews the academic literature, government and professional association reports, and publicly available data to summarize what we know about who becomes a postdoc. As scientists become more likely to participate and persist in postdoctoral appointments, scientists and those who employ, fund, organize, and support them would like to better understand who becomes a postdoc and why. Although many of the most talented new PhDs become postdocs, there is concern that their talents are not fully utilized in these appointments. One way to approach the question of who becomes a postdoc is by examining individual characteristics like personal motivation, human capital, and demographics. Another approach considers the role of characteristics of the doctoral institution. This review considers both approaches to integrate our knowledge of individual and institutional determinants of postdoctoral study. Introduction