91 research outputs found
Mobilizing Public Support for the United Nations
This paper examines a critical case of Executive Branch leadership during the creation of the United Nations. Before his death, President Franklin Roosevelt hoped that the wartime alliance would become the cornerstone of postwar inter- national security. The U.N. charter, ratified in July 1945, marked the end of the State Department's four-year effort to reinvent the League of Nations and pro- mote postwar peace and security. This case study explores the State Department's public leadership efforts—in the form of a concerted, nationwide campaign to educate the American people and their leaders in Congress about the merits of U.S. involvement in the new international organization.
In its effort to commit the American people to multilateral engagement in the postwar world, the U.S. government distributed some 2.1 million educational publications through over four hundred citizen groups. It conducted a nation- wide series of public meetings, speeches and national radio broadcasts, and created the State Department's first public affairs office to monitor public opinion and to coordinate outreach.
In describing the campaign, the case study addresses a number of important questions for students of leadership and public policy, including: How did the State Department respond to specific challenges that it faced throughout the campaign? How can leaders promote a greater interest in and knowledge about policy decisions that affect American interests in the world? And how can leaders reach their target audience
HI in Virgo's "Red and Dead" Dwarf Ellipticals - A Tidal Tail and Central Star Formation
We investigate a sample of 3 dwarf elliptical galaxies in the Virgo Cluster
which have significant reservoirs of HI. We present deep optical imaging (from
CFHT and KPNO), HI spectra (Arecibo) and resolved HI imaging (VLA) of this
sample. These observations confirm their HI content and optical morphologies,
and indicate that the gas is unlikely to be recently accreted. The sample has
more in common with dwarf transitionals, although dwarf transitionals are
generally lower in stellar mass and gas fraction. VCC 190 has an HI tidal tail
from a recent encounter with the massive spiral galaxy NGC 4224. In VCC 611,
blue star-forming features are observed which were unseen by shallower SDSS
imaging.Comment: 11 pages, 6 figures, accepted in A
ALFALFA and WSRT Imaging of Extended H I Features in the Leo Cloud of Galaxies
We present ALFALFA HI observations of a well studied region of the Leo Cloud,
which includes the NGC 3227 group and the NGC 3190 group. We detect optically
dark HI tails and plumes with extents potentially exceeding 600 kpc, well
beyond the field of view of previous observations. These HI features contain
approximately 40% of the total HI mass in the NGC~3227 group and 10% in the
NGC~3190 group. We also present WSRT maps which show the complex morphology of
the extended emission in the NGC~3227 group. We comment on previously proposed
models of the interactions in these groups and the implications for the scale
of group processing through interactions. Motivated by the extent of the HI
plumes, we place the HI observations in the context of the larger loose group,
demonstrating the need for future sensitive, wide field HI surveys to
understand the role of group processing in galaxy evolution.Comment: 17 pages, 9 figures, accepted for publication in MNRA
The ALFALFA "Almost Darks" Campaign: Pilot VLA HI Observations of Five High Mass-to-Light Ratio Systems
We present VLA HI spectral line imaging of 5 sources discovered by ALFALFA.
These targets are drawn from a larger sample of systems that were not uniquely
identified with optical counterparts during ALFALFA processing, and as such
have unusually high HI mass to light ratios. These candidate "Almost Dark"
objects fall into 4 categories: 1) objects with nearby HI neighbors that are
likely of tidal origin; 2) objects that appear to be part of a system of
multiple HI sources, but which may not be tidal in origin; 3) objects isolated
from nearby ALFALFA HI detections, but located near a gas-poor early-type
galaxy; 4) apparently isolated sources, with no object of coincident redshift
within ~400 kpc. Roughly 75% of the 200 objects without identified counterparts
in the .40 database (Haynes et al. 2011) fall into category 1. This
pilot sample contains the first five sources observed as part of a larger
effort to characterize HI sources with no readily identifiable optical
counterpart at single dish resolution. These objects span a range of HI mass
[7.41 < log(M) < 9.51] and HI mass to B-band luminosity ratios (3 <
M/L < 9). We compare the HI total intensity and velocity
fields to SDSS optical imaging and to archival GALEX UV imaging. Four of the
sources with uncertain or no optical counterpart in the ALFALFA data are
identified with low surface brightness optical counterparts in SDSS imaging
when compared with VLA HI intensity maps, and appear to be galaxies with clear
signs of ordered rotation. One source (AGC 208602) is likely tidal in nature.
We find no "dark galaxies" in this limited sample. The present observations
reveal complex sources with suppressed star formation, highlighting both the
observational difficulties and the necessity of synthesis follow-up
observations to understand these extreme objects. (abridged)Comment: Astronomical Journal, in pres
The Enigmatic (Almost) Dark Galaxy Coma P: Distance Measurement and Stellar Populations from HST Imaging
We present Hubble Space Telescope (HST) observations of the low surface
brightness (SB) galaxy Coma P. This system was first discovered in the Arecibo
Legacy Fast ALFA HI survey and was cataloged as an (almost) dark galaxy because
it did not exhibit any obvious optical counterpart in the available survey data
(e.g., Sloan Digital Sky Survey). Subsequent WIYN pODI imaging revealed an
ultra-low SB stellar component located at the center of the HI detection. We
use the HST images to produce a deep color-magnitude diagram (CMD) of the
resolved stellar population present in Coma P. We clearly detect a red stellar
sequence that we interpret to be a red giant branch, and use it to infer a tip
of the red giant branch (TRGB) distance of 5.50 Mpc. The new
distance is substantially lower than earlier estimates and shows that Coma P is
an extreme dwarf galaxy. Our derived stellar mass is only 4.3 10
, meaning that Coma P has an extreme HI-to-stellar mass ratio of 81.
We present a detailed analysis of the galaxy environment within which Coma P
resides. We hypothesize that Coma P formed within a local void and has spent
most of its lifetime in a low-density environment. Over time, the gravitational
attraction of the galaxies located in the void wall has moved it to the edge,
where it had a recent "fly-by" interaction with M64. We investigate the
possibility that Coma P is at a farther distance and conclude that the
available data are best fit by a distance of 5.5 Mpc.Comment: 22 pages, 11 figures. Accepted for publication in the Astronomical
Journa
VLA Imaging of H i-bearing Ultra-Diffuse Galaxies from the ALFALFA Survey
Ultra-diffuse galaxies have generated significant interest due to their large optical extents and low optical surface brightnesses, which challenge galaxy formation models. Here we present resolved synthesis observations of 12 H i-bearing ultra-diffuse galaxies (HUDs) from the Karl G. Jansky Very Large Array (VLA), as well as deep optical imaging from the WIYN 3.5-meter telescope at Kitt Peak National Observatory. We present the data processing and images, including total intensity H i maps and H i velocity fields. The HUDs show ordered gas distributions and evidence of rotation, important prerequisites for the detailed kinematic models in Mancera PiËœna et al. (2019b). We compare the H i and stellar alignment and extent, and find the H i extends beyond the already extended stellar component and that the H i disk is often misaligned with respect to the stellar one, emphasizing the importance of caution when approaching inclination measurements for these extreme sources. We explore the H i mass-diameter scaling relation, and find that although the HUDs have diffuse stellar populations, they fall along the relation, with typical global H i surface densities. This resolved sample forms an important basis for more detailed study of the H i distribution in this extreme extragalactic population
VLA Imaging of H I-bearing Ultra-diffuse Galaxies from the ALFALFA Survey
Ultra-diffuse galaxies have generated significant interest due to their large optical extents and low optical surface brightnesses, which challenge galaxy formation models. Here we present resolved synthesis observations of 12 H i-bearing ultra-diffuse galaxies (HUDs) from the Karl G. Jansky Very Large Array (VLA), as well as deep optical imaging from the WIYN 3.5-meter telescope at Kitt Peak National Observatory. We present the data processing and images, including total intensity H i maps and H i velocity fields. The HUDs show ordered gas distributions and evidence of rotation, important prerequisites for the detailed kinematic models in Mancera PiËœna et al. (2019b). We compare the H i and stellar alignment and extent, and find the H i extends beyond the already extended stellar component and that the H i disk is often misaligned with respect to the stellar one, emphasizing the importance of caution when approaching inclination measurements for these extreme sources. We explore the H i mass-diameter scaling relation, and find that although the HUDs have diffuse stellar populations, they fall along the relation, with typical global H i surface densities. This resolved sample forms an important basis for more detailed study of the H i distribution in this extreme extragalactic population
Fronto-striatal alterations correlate with apathy severity in behavioral variant frontotemporal dementia
Structural and functional changes in cortical and subcortical regions have been reported in behavioral variant frontotemporal dementia (bvFTD), however, a multimodal approach may provide deeper insights into the neural correlates of neuropsychiatric symptoms. In this multicenter study, we measured cortical thickness (CTh) and subcortical volumes to identify structural abnormalities in 37 bvFTD patients, and 37 age- and sex-matched healthy controls. For seed regions with significant structural changes, whole-brain functional connectivity (FC) was examined in a sub-cohort of N = 22 bvFTD and N = 22 matched control subjects to detect complementary alterations in brain network organization. To explore the functional significance of the observed structural and functional deviations, correlations with clinical and neuropsychological outcomes were tested where available. Significantly decreased CTh was observed in the bvFTD group in caudal middle frontal gyrus, left pars opercularis, bilateral superior frontal and bilateral middle temporal gyrus along with subcortical volume reductions in bilateral basal ganglia, thalamus, hippocampus, and amygdala. Resting-state functional magnetic resonance imaging showed decreased FC in bvFTD between: dorsal striatum and left caudal middle frontal gyrus;putamen and fronto-parietal regions;pallidum and cerebellum. Conversely, bvFTD showed increased FC between: left middle temporal gyrus and paracingulate gyrus;caudate nucleus and insula;amygdala and parahippocampal gyrus. Additionally, cortical thickness in caudal, lateral and superior frontal regions as well as caudate nucleus volume correlated negatively with apathy severity scores of the Neuropsychiatry Inventory Questionnaire. In conclusion, multimodal structural and functional imaging indicates that fronto-striatal regions have a considerable influence on the severity of apathy in bvFTD
- …