Galactic substructure traced by RR Lyraes in SDSS Stripe 82

Using a sample of 407 RR Lyrae stars extracted from SDSS Stripe 82, we study the degree of substructure in the Galactic halo. We identify overdensities associated with the known substructures of the Hercules-Aquila Cloud and the Sagittarius Stream, and find a further previously-unknown substructure, the Pisces Overdensity, at ~100 kpc from the Sun. Together, the three substructures account for ~80% of our RR Lyrae sample. We also study the density distribution of RR Lyraes in the halo and find that the profile is best fit by a broken power law with an inner slope of -2.4 and a break radius of ~25 kpc, consistent with previous studies. We conclude that the halo is predominantly made up of the debris from in-falling satellites, with little or no underlying smooth component.Comment: 4 pages, 2 figures, to appear in the proceedings of "Assembling the Puzzle of the Milky Way", Le Grand Bornand (Apr. 17-22, 2011), C. Reyle, A. Robin, M. Schultheis (eds.

A discrete chemo-dynamical model of the dwarf spheroidal galaxy Sculptor: mass profile, velocity anisotropy and internal rotation

We present a new discrete chemo-dynamical axisymmetric modeling technique, which we apply to the dwarf spheroidal galaxy Sculptor. The major improvement over previous Jeans models is that realistic chemical distributions are included directly in the dynamical modelling of the discrete data. This avoids loss of information due to spatial binning and eliminates the need for hard cuts to remove contaminants and to separate stars based on their chemical properties. Using a combined likelihood in position, metallicity and kinematics, we find that our models naturally separate Sculptor stars into a metal-rich and a metal-poor population. Allowing for non-spherical symmetry, our approach provides a central slope of the dark matter density of $\gamma = 0.5 \pm 0.3$. The metal-rich population is nearly isotropic (with $\beta_r^{red} = 0.0\pm0.1$) while the metal-poor population is tangentially anisotropic (with $\beta_r^{blue} = -0.2\pm0.1$) around the half light radius of $0.26$ kpc. A weak internal rotation of the metal-rich population is revealed with $v_{max}/\sigma_0 = 0.15 \pm 0.15$. We run tests using mock data to show that a discrete dataset with $\sim 6000$ stars is required to distinguish between a core ($\gamma = 0$) and cusp ($\gamma = 1$), and to constrain the possible internal rotation to better than $1\,\sigma$ confidence with our model. We conclude that our discrete chemo-dynamical modelling technique provides a flexible and powerful tool to robustly constrain the internal dynamics of multiple populations, and the total mass distribution in a stellar system.Comment: Accepted by MNRA

Vertical development: cultivating mindsets, emotions, and habits to lead effectively

The lesser-known field of adult development psychology, often called vertical development, is at least as important as neuroscience for truly understanding how we and others tick, how to get the best out of people, and how to navigate difficult situations. Vanessa Dietzel and Laura Watkins suggest some exercises that will help us build “muscles” for vertical development

Studying Gender in Conference Talks -- data from the 223rd meeting of the American Astronomical Society

We present a study on the gender balance, in speakers and attendees, at the recent major astronomical conference, the American Astronomical Society meeting 223, in Washington, DC. We conducted an informal survey, yielding over 300 responses by volunteers at the meeting. Each response included gender data about a single talk given at the meeting, recording the gender of the speaker and all question-askers. In total, 225 individual AAS talks were sampled. We analyze basic statistical properties of this sample. We find that the gender ratio of the speakers closely matched the gender ratio of the conference attendees. The audience asked an average of 2.8 questions per talk. Talks given by women had a slightly higher number of questions asked (3.2$\pm$0.2) than talks given by men (2.6$\pm$0.1). The most significant result from this study is that while the gender ratio of speakers very closely mirrors that of conference attendees, women are under-represented in the question-asker category. We interpret this to be an age-effect, as senior scientists may be more likely to ask questions, and are more commonly men. A strong dependence on the gender of session chairs is found, whereby women ask disproportionately fewer questions in sessions chaired by men. While our results point to laudable progress in gender-balanced speaker selection, we believe future surveys of this kind would help ensure that collaboration at such meetings is as inclusive as possible.Comment: 4 pages, 5 figures. Comments welcome

A Laboratory Test of Alcohol-Related Intimate Partner Aggression: Expectancies Are Not to Blame

Background: The role of alcohol expectancies and evaluations (i.e., perceived outcomes of drinking and whether these outcomes are desirable) in alcohol-related intimate partner aggression (IPA) has been debated, with some researchers arguing that expectancies fully account for the alcohol-IPA relationship and others suggesting they play a minimal if any role in alcohol-related IPA. In the current study, we examine the impact of expectancies and evaluations on alcohol-related IPA observed in the lab, in order to clarify what impact, if any, alcohol expectancies have on alcohol-related IPA. Consistent with findings from laboratory studies examining general aggression, we expected that individuals who were intoxicated would display greater IPA than individuals who were sober, but that alcohol expectancies and evaluations would be unrelated to in vivo IPA. Method: Participants were 69 dating couples (total N = 138), randomly assigned to consume either an alcohol or placebo beverage. IPA was measured with an in vivo aggression task based on the Taylor Aggression Paradigm. Results: As expected, alcohol intoxication predicted in vivo IPA following provocation (p \u3c .03), whereas alcohol expectancies and evaluations were not related to IPA. Conclusions: These findings provide further support that alcohol expectancies and evaluations play little if any role in alcohol-related IPA. Rather, intoxication likely increases risk for IPA through its physiological effects on perception and thought. Further, treatments targeting alcohol use, rather than beliefs about outcomes of drinking, may have a greater impact on alcohol-related IPA

The Cyber Aggression in Relationships Scale: A New Multidimensional Measure of Technology-Based Intimate Partner Aggression

The purpose of this study was to develop and provide initial validation for a measure of adult cyber intimate partner aggression (IPA): the Cyber Aggression in Relationships Scale (CARS). Drawing on recent conceptual models of cyber IPA, items from previous research exploring general cyber aggression and cyber IPA were modified and new items were generated for inclusion in the CARS. Two samples of adults 18 years or older were recruited online. We used item factor analysis to test the factor structure, model fit, and invariance of the measure structure across women and men. Results confirmed that three-factor models for both perpetration and victimization demonstrated good model fit, and that, in general, the CARS measures partner cyber aggression similarly for women and men. The CARS also demonstrated validity through significant associations with in-person IPA, trait anger, and jealousy. Findings suggest the CARS is a useful tool for assessing cyber IPA in both research and clinical settings