Naval Postgraduate School Board of Advisors Subcommittee Meeting 25-26 April 2012

Minutes of the April 2012 BOA Meeting in Monterey, California

Board of Advisors to the Presidents of the Naval Postgraduate School and Naval War College report of the April 2013 meeting of the Board of Advisors Naval Postgraduate School subcommittee

Official correspondence reporting on the April 2013 meeting of the BOA, NPS subcommittee

Images and nonlocal vortex pinning in thin superfluid films

For thin films of superfluid adsorbed on a disordered substrate, we derive the equation of motion for a vortex in the presence of a random potential within a mean field (Hartree) description of the condensate. The compressible nature of the condensate leads to an effective pinning potential experienced by the vortex which is nonlocal, with a long range tail that smoothes out the random potential coupling the condensate to the substrate. We interpret this nonlocality in terms of images, and relate the effective potential governing the dynamics to the pinning energy arising from the expectation value of the Hamiltonian with respect to the vortex wavefunction.Comment: 19 pages, revtex, to appear Phys. Rev.

Quantifying Kinematic Substructure in the Milky Way's Stellar Halo

We present and analyze the positions, distances, and radial velocities for over 4000 blue horizontal-branch (BHB) stars in the Milky Way's halo, drawn from SDSS DR8. We search for position-velocity substructure in these data, a signature of the hierarchical assembly of the stellar halo. Using a cumulative "close pair distribution" (CPD) as a statistic in the 4-dimensional space of sky position, distance, and velocity, we quantify the presence of position-velocity substructure at high statistical significance among the BHB stars: pairs of BHB stars that are close in position on the sky tend to have more similar distances and radial velocities compared to a random sampling of these overall distributions. We make analogous mock-observations of 11 numerical halo formation simulations, in which the stellar halo is entirely composed of disrupted satellite debris, and find a level of substructure comparable to that seen in the actually observed BHB star sample. This result quantitatively confirms the hierarchical build-up of the stellar halo through a signature in phase (position-velocity) space. In detail, the structure present in the BHB stars is somewhat less prominent than that seen in most simulated halos, quite possibly because BHB stars represent an older sub-population. BHB stars located beyond 20 kpc from the Galactic center exhibit stronger substructure than at $\rm r_{gc} < 20$ kpc.Comment: 29 page, 10 figures, 1 table; accepted by APJ; for related article by another group see arXiv:1011.192

The Impact of an Interprofessional Geriatric Training Experience: Attitudes of Future Healthcare Providers

As the older adult population increases, it is vital to educate and train healthcare providers as members of interprofessional healthcare teams who can work effectively with these individuals. Ageism is a potential obstacle to achieving this goal. The purpose of this pre/post-test design pilot study was to determine the impact of an interprofessional geriatric training experience on the attitudes of future healthcare providers towards interprofessionalism and working with older adults. Sixteen graduate level students from occupational therapy and clinical psychology programs completed four interprofessional sessions with older adults residing in a long-term care facility. Quantitative data were gathered from pre/post-test scores on three instruments: (1) Self-Perceptions and Older Adults Questionnaire; (2) A Refined Version of Aging Semantic Differential; and (3) Readiness for Interprofessional Learning Scale. Results of paired sample t tests indicated that participants described older adults significantly more positively and their perceptions about working with older adults became significantly more positive following the interprofessional geriatric training experience. Additional data were gathered regarding participants’ perceptions of the interprofessional training experiences at the conclusion of the study. This feedback regarding students’ perceptions of the interprofessional geriatric training experiences indicated that the majority of the participants found the experiences with the older adults to be valuable and that the interprofessional learning activities helped them better understand the older adults. The results of this pilot study suggest that even short-term interprofessional experiences may have the ability to positively influence the attitudes of future healthcare providers regarding older adults

Effectiveness of an Interprofessional Education Event for Graduate Health Professional Students

ABSTRACT Purpose: The purpose of this study was to investigate the impact of a single, optional, half-day, interprofessional education (IPE) event for a myriad of graduate-level health professional students (n=44) at a university in Illinois, USA. Methods: The researchers in this study examined students’ performance on two out of six of the domains on the Interprofessiomnal Collaborator Assessment Rubric (ICAR): Roles and Responsibilities and Communication Strategies. This study also investigated quantitative and qualitative findings related to student perceptions regarding this IPE opportunity. Results: Results indicated that students met or exceeded the minimum competency for the ranking of “developing” for all 6 of the behaviors evaluated. Results also revealed that this half-day extracurricuricular IPE event was viewed favorably by health-professional students and created a venue whereby students belonging to different health professional programs can enter into discussions and learn about each others’ respective roles and responsibilities in patient care. Conclusion: The creation and implementation of short term extracurricular IPE events may be a valuable alternative for healthcare programs that are unable to implement IPE activities due to some of the common barriers impacting the development, implementation, or continuation of IPE opportunities

The Structure of the Sagittarius Stellar Stream as Traced by Blue Horizontal Branch Stars

We use a sample of blue horizontal branch (BHB) stars from the Sloan Digital Sky Survey Data Release 7 to explore the structure of the tidal tails from the Sagittarius Dwarf Galaxy. We use a method yielding BHB star candidates with up to ~70% purity from photometry alone. The resulting sample has a distance precision of roughly 5% and can probe distances in excess of 100 kpc. Using this sample, we identify a possible extension to the trailing arm at distances of 60-80 kpc from the Sun with an estimated significance of at least 3.8 sigma. Current models predict that a distant `returning' segment of the debris stream should exist, but place it substantially closer to the Sun where no debris is observed in our data. Exploiting the distance precision of our tracers, we estimate the mean line-of-sight thickness of the leading arm to be ~3 kpc, and show that the two `bifurcated' branches of the debris stream differ by only 1-2 kpc in distance. With a spectroscopic very pure BHB star subsample, we estimate the velocity dispersion in the leading arm, 37 km s^-1, which is in reasonable agreement with models of Sgr disruption. We finally present a sample of high-probability Sgr BHB stars in the leading arm of Sgr, selected to have distances and velocities consistent with Sgr membership, to allow further study.Comment: Astrophysical Journal, in press. 17 pages, 15 figure

Genome-Scale Oscillations in DNA Methylation during Exit from Pluripotency

Pluripotency is accompanied by the erasure of parental epigenetic memory, with naive pluripotent cells exhibiting global DNA hypomethylation both in vitro and in vivo. Exit from pluripotency and priming for differentiation into somatic lineages is associated with genome-wide de novo DNA methylation. We show that during this phase, co-expression of enzymes required for DNA methylation turnover, DNMT3s and TETs, promotes cell-to-cell variability in this epigenetic mark. Using a combination of single- cell sequencing and quantitative biophysical modeling, we show that this variability is associated with coherent, genome-scale oscillations in DNA methylation with an amplitude dependent on CpG density. Analysis of parallel single-cell transcriptional and epigenetic profiling provides evidence for oscillatory dynamics both in vitro and in vivo. These observations provide insights into the emergence of epigenetic heterogeneity during early embryo development, indicating that dynamic changes in DNA methylation might influence early cell fate decisions

Galactic Globular and Open Clusters in the Sloan Digital Sky Survey. I. Crowded Field Photometry and Cluster Fiducial Sequences in ugriz

We present photometry for globular and open cluster stars observed with the Sloan Digital Sky Survey (SDSS). In order to exploit over 100 million stellar objects with r < 22.5 mag observed by SDSS, we need to understand the characteristics of stars in the SDSS ugriz filters. While star clusters provide important calibration samples for stellar colors, the regions close to globular clusters, where the fraction of field stars is smallest, are too crowded for the standard SDSS photometric pipeline to process. To complement the SDSS imaging survey, we reduce the SDSS imaging data for crowded cluster fields using the DAOPHOT/ALLFRAME suite of programs and present photometry for 17 globular clusters and 3 open clusters in a SDSS value-added catalog. Our photometry and cluster fiducial sequences are on the native SDSS 2.5-meter ugriz photometric system, and the fiducial sequences can be directly applied to the SDSS photometry without relying upon any transformations. Model photometry for red giant branch and main-sequence stars obtained by Girardi et al. cannot be matched simultaneously to fiducial sequences; their colors differ by ~0.02-0.05 mag. Good agreement (< ~0.02 mag in colors) is found with Clem et al. empirical fiducial sequences in u'g'r'i'z' when using the transformation equations in Tucker et al.Comment: 30 pages, 25 figures. Accepted for publication in ApJS. Version with high resolution figures available at http://www.astronomy.ohio-state.edu/~deokkeun/AnJohnson.pd