Blue Stragglers in Low-Luminosity Star Clusters

We examine the blue straggler populations of 13 low-luminosity (M_V_t >~ -6) globular clusters and 2 old open clusters. These clusters test blue straggler formation in environments intermediate between higher luminosity (and usually higher density) clusters and the Galactic field. The anti-correlation between the relative frequency of blue stragglers (F_BSS = N_BSS / N_HB) and cluster luminosity continues to the lowest luminosity clusters, which have frequencies meeting or exceeding that of field stars. In addition we find that the anti-correlation between straggler frequency and central density disappears for clusters with density less than about 300 L_V,sun pc^-3, although this appears to be an artifact of the correlation between cluster luminosity and central density. We argue on observational (wide, eccentric binaries containing blue stragglers in M67, and the existence of very bright stragglers in most of the clusters in our sample) and theoretical grounds that stellar collisions still produce a significant fraction of the blue stragglers in low luminosity star clusters due to the long-term survival of wide binaries.Comment: 13 pages, 3 figures, accepted to ApJ Letter

N-Cadherin Expression And EMT Progression In Arsenic- And Cadmium-Transformed Urotsa

Environmental agents are common causes of bladder cancer. Specifically, arsenic (As3+) and cadmium (Cd2+) are known carcinogens implicated in the development of bladder cancer. Previous studies from our laboratory have shown that As3+ and Cd2+ can cause malignant transformation of normal immortalized bladder urothelial cells, which can form tumors when injected subcutaneous or intraperitoneal into nude mice. Microarray analysis of repeated metal transformation in parallel revealed that N-cadherin was the most upregulated gene in As3+ transformants, and a top induced gene in Cd2+-transformed cells. The switch from E-cadherin to N-cadherin is a well-known indicator of the epithelial-to-mesenchymal transition occurring in bladder cancer. Further, N-cadherin upregulation is correlated with tumor stage, increased recurrence, and decreased survival in patients. While the factors mediating the decrease in E-cadherin expression are well-established, little is known of the factors regulating the increase in N-cadherin expression. The goal of the present study was to determine how As3+ and Cd2+ regulate N-cadherin expression, whether this expression is maintained in heterotransplant models, and if N-cadherin is promoting the epithelial-to-mesenchymal transition in As3+- and Cd2+-transformed UROtsa cells in vitro. This work has demonstrated that N-cadherin is induced in As3+- and Cd2+-transformed UROtsa cell lines, and that the expression is maintained in intraperitoneal, but not subcutaneous, tumor xenografts. Further, tumor-initiating cells derived from transformed UROtsa cells did not express N-cadherin. This suggests that tumor microenvironment and heterogeneity of cell populations are important factors for the use of animal models in cancer research. The As3+ and Cd2+ UROtsa cell lines represent the initial phases of EMT in bladder cancer, and may demonstrate a unique EMT pathway specific to heavy metal carcinogens. Transcriptional regulation of N-cadherin, which is mostly unknown, may be elucidated by the investigation of the transcription factor Twist and epigenetic regulation, particularly histone acetylation

Exploiting the open clusters in the Kepler and CoRoT fields

The open clusters in the Kepler and CoRoT fields potentially provide tight constraints for tests of stellar models and observational methods because they allow a combination of complementary methods. We are in the process of identi- fying and measuring parameters for detached eclipsing binaries (dEBs) in the open clusters in the Kepler and CoRoT fields. We make use of measurements of dEBs in the clusters to test the accuracy of asteroseismic scaling relations for mass. We are able to provide strong indications that the asteroseismic scaling relations over- estimate the stellar mass, but we are not yet able to distinguish between different proposed corrections from the literature. We argue how our ongoing measurements of more dEBs in more clusters, complemented by dEBs in the field, should be able to break the degeneracy. We also briefly describe how we can identify cluster stars that have evolved through non-standard evolution by making use of ensemble asteroseismology.Comment: Proc. of the workshop "Asteroseismology of stellar populations in the Milky Way" (Sesto, 22-26 July 2013), Astrophysics and Space Science Proceedings, (eds. A. Miglio, L. Girardi, P. Eggenberger, J. Montalban

Staff Perspectives on Inclusion in Early Childhood

Inclusion of young children with disabilities in early childhood settings has become a priority for many early childhood professionals and programs. Unfortunately there continues to be a large number of programs and schools who have not yet realized the benefits of this type of programming for most young children with disabilities. In this case study, a survey research design was used to examine the perspectives of staff who work in the early childhood programs within a single school district. Overall, the staff reported benefits to students who participate in inclusive programming versus pull out or self-contained programming

Effect of Simulated Storage and Distribution on Listeria innocua Growth in Non-Traditional Salad Ingredients

The fresh-cut produce industry has seen expansive growth in recent years, to meet consumer demand ready-to-eat (RTE) salads have included the use of non-traditional ingredients. Uncommon ingredients include beet greens, kale, broccoli stalk, and Brussels sprouts, since these ingredients have not historically been consumed raw, potential food safety issues should be reassessed. Current processing technologies include produce washes that can reduce microbial levels but do not eradicate all populations. The lack of a kill step in produce processing emphasizes the need to minimize pathogen contamination during production and growth during a product’s shelf life. Listeria monocytogenes, a leading cause of foodborne illness related deaths, continues to challenge the industry with recent outbreaks and recalls of fresh-cut produce. These events present the need to better understand L. monocytogenes growth potential in RTE produce during storage and distribution. Traditional salad greens have been researched extensively, however, limited knowledge is available on new inclusions. While temperature is known to strongly influence microbial growth, the effects of physical abuse during storage and distribution are unknown. The purpose of this study was to characterize L. innocua’s, a surrogate for L. monocytogenes, growth behavior in processed beet greens, kale, broccoli stalk, and Brussels sprouts when exposed to simulated physical and thermal abuses during storage and distribution. To evaluate L. innocua growth during storage and distribution produce samples were obtained from a local processor in retail packaging and surface inoculated. The samples were conditioned at 4℃ for 18h prior to being exposed to a series of physical abuses (compression, drop, and vibration) typical of storage and distribution. After abuse, produce was incubated at 4 or 8°C and sampled post-abuse through 16 and 11 days, respectively. Samples were enumerated for L. innocua, aerobic and psychrotrophic microorganisms, and lactic acid bacteria. To monitor growing conditions in each vegetable, product pH, water activity, and headspace (gas analysis), were observed at each time pull. The study found physical abuse had no significant effect on L. innocua, or microbiota growth regardless of vegetable or incubation temperature (P \u3e 0.05). Vegetable intrinsic factors (pH, Aw, and headspace) did not seem to interfere in L. innocua or background microbiota growth during incubation. All vegetables supported L. innocua growth under 8℃. Growth of L. innocua was greatest in beet greens, followed by kale, broccoli stalk, and Brussels sprouts in descending order. Significant growth of L. innocua at 4 and 8ᵒC was seen on day 6 and 4 in beet greens, 11 and 6 in Brussels sprouts, 16 and 4 in kale, and 16 and 6 in broccoli stalk (P \u3c 0.05). Overall, these results show the studied RTE vegetables can support L. monocytogenes growth during storage and distribution, especially under abusive temperatures, demonstrating the importance of prevention strategies during processing and refrigeration throughout RTE produce shelf life