Giant Halos in Dwarf Irregular Galaxies vs. Dwarf Elliptical Galaxies

We present a discovery of a giant stellar halo in NGC 6822, a dwarf irregular galaxy in the Local Group. This halo is mostly made of old red giants, showing striking features: 1) it is several times larger than the main body of the galaxy seen in the optical images, and 2) it is elongated in the direction almost perpendicular to the HI disk of NGC 6822. The structure of this stellar halo looks similar to the shape of dwarf elliptical galaxies, indicating that the halos of dwarf irregular galaxies share the same origin with those of the dwarf elliptical galaxies.Comment: 4 pages, 3 figures, proceedings of IAU Colloquium 198, "Near-Field Cosmology With Dwarf Elliptical Galaxies", editors H. Jerjen and B. Binggeli, Cambridge University Pres

Star Cluster Population of the Interacting Galaxy System M51

We present a star cluster population study in the interacting galaxy system M51 based on HST ACS BVI mosaic images taken by the Hubble Heritage Team to commemorate the HST's 15th anniversary. We have found and classified star clusters in M51 using SExtractor and visual inspection. We have derived the photometry, size, and age of the clusters. It is found that the companion SB0 galaxy NGC 5195 harbors about 50 faint fuzzy clusters and that the age distribution of star clusters appears to be correlated with the epochs of dynamical events in M51 system.Comment: 2 pages, 2 figures. To appear in the Proceedings of IAU Symposium 241: "Stellar Populations as Building Blocks of Galaxies", 10-16 December, 2006 at La Palma, Canary Islands, Spain. Errors in the reference list were correcte

Understanding how change occurs for women of childbearing age : the role of depression and marijuana use on reducing alcohol consumption

Alcohol and marijuana are reportedly two of the most pervasively used substances in the United States among women of childbearing age (18-44 years). About 10–50% of childbearing-aged women report drinking alcohol and are at risk of an Alcohol-Exposed Pregnancy (AEP). As for marijuana use, about 9.5% of women of childbearing age report marijuana use in the past month, and use has been steadily increasing since 2007. Further compounding concerns for women include mental health disorders like depression. Among women of childbearing age, studies have estimated that about 8-16% suffer from depression. Furthermore, it is all too common for both substance use and mental health disorders to co-occur. Comorbid substance use and mental health disorders among women of childbearing age have emerged as a particularly significant area of concern. However, a key obstacle in further understanding the relationship between these disorders among women, in general, is that women either do not report, or under-report substance abuse and mental health symptoms, and may not be aware of the concerns associated with substance use while at risk for pregnancy. Therefore, it is critical to find a setting where women can receive information about alcohol- and substance-exposed pregnancies, while also identifying and treating these co-occurring disorders. This dissertation explores the feasibility of meeting these needs through primary care settings. Primary care, identified as an “opportunistic setting,” is often the first setting substance use and mental disorders are detected and addressed. However, comorbidity in primary care has not been explored in detail, more so for women of childbearing age, and requires further examination. Alcohol use, marijuana use, and depression are all critical issues for childbearing-aged women, and often occur concurrently, yet research is limited and needs further attention. Therefore, this dissertation aims to better understand comorbid alcohol use and depression, and comorbid alcohol use and marijuana use among women of childbearing age presenting in primary care. To do so, this dissertation draws upon the Transtheoretical Model of Change to study a sample of women from the CDC-funded CHOICES Plus study who were at risk of an AEP.Social Wor

Constructive Roles of Organizational Two-Way Symmetrical Communication: Workplace Pseudo-Information Gatekeeping

Misinformation, misunderstanding, and rumors are not foreign to organizations. The cost of pseudo-information can be critical for the organization in terms of profit, stakeholder relationships, and reputation. For those reasons, organizations should make efforts to detect and prevent the spread of pseudo-information. This piece of research proposes and finds support in a model to gatekeep pseudo-information in the workplace, in which two-way symmetrical communication is an essential element for the model, predicting employees’ gatekeeping behaviors, and mediating the relationship between quality of the employee–organization relationship and gatekeeping behaviors. Then, the cultivation of relationships with the employees and the adherence to two-way symmetrical communication are cost-effective methods for the organization. Loyal and satisfied employees voluntarily debunk and combat pseudo-information

What Makes Lyα\alpha Nebulae Glow? Mapping the Polarization of LABd05

"Ly$\alpha$ nebulae" are giant ($\sim$100 kpc), glowing gas clouds in the distant universe. The origin of their extended Ly$\alpha$ emission remains a mystery. Some models posit that Ly$\alpha$ emission is produced when the cloud is photoionized by UV emission from embedded or nearby sources, while others suggest that the Ly$\alpha$ photons originate from an embedded galaxy or AGN and are then resonantly scattered by the cloud. At least in the latter scenario, the observed Ly$\alpha$ emission will be polarized. To test these possibilities, we are conducting imaging polarimetric observations of seven Ly$\alpha$ nebulae. Here we present our results for LABd05, a cloud at $z$ = 2.656 with an obscured, embedded AGN to the northeast of the peak of Ly$\alpha$ emission. We detect significant polarization. The highest polarization fractions $P$ are $\sim$10-20% at $\sim$20-40 kpc southeast of the Ly$\alpha$ peak, away from the AGN. The lowest $P$, including upper-limits, are $\sim$5% and lie between the Ly$\alpha$ peak and AGN. In other words, the polarization map is lopsided, with $P$ increasing from the Ly$\alpha$ peak to the southeast. The measured polarization angles $\theta$ are oriented northeast, roughly perpendicular to the $P$ gradient. This unique polarization pattern suggests that 1) the spatially-offset AGN is photoionizing nearby gas and 2) escaping Ly$\alpha$ photons are scattered by the nebula at larger radii and into our sightline, producing tangentially-oriented, radially-increasing polarization away from the photoionized region. Finally we conclude that the interplay between the gas density and ionization profiles produces the observed central peak in the Ly$\alpha$ emission. This also implies that the structure of LABd05 is more complex than assumed by current theoretical spherical or cylindrical models.Comment: 11 pages, 8 figure

An Oscillatory Path to Vaccination: The Roles of Normative and Epistemic Factors in Explaining Vaccination Hesitancy in COVID-19.

This study examined the roles of normative and epistemic factors in influencing individuals\u27 reluctance to be vaccinated during the COVID-19 pandemic. Individuals\u27 ethical orientations (IEO; teleology vs. deontology) were introduced as normative characteristics, while COVID-19 vaccine conspiracy beliefs and vaccine knowledge were addressed as issue-specific epistemic factors. We conducted two online surveys to investigate each of these three factors\u27 influences on the level of Americans\u27 reluctance to receive COVID-19 vaccines. Combinations of these factors that predict COVID-19 vaccination hesitancy levels were also explored to provide integrated perspectives in the specific vaccination context. Our findings demonstrated the positive association between IEO and reluctance to receive COVID-19 vaccines. Significant interactions between 1) COVID-19 vaccine conspiracy beliefs and IEO and 2) conspiracy beliefs and vaccine knowledge were also identified. Implications, limitations, and suggestions for future study were addressed