26,357 research outputs found
The Neutral Hydrogen Kinematics of the Dwarf Galaxy Merger NGC 3239
We present H I spectral line images of the nearby dwarf galaxy NGC 3239. The galaxy’s curious morphology suggests that it is a post-merger system. We propose that NGC 3239 is a merger because it has multiple tidal tails, an enhanced velocity dispersion throughout the disk, and widespread star formation. We have produced kinematic moment maps corresponding to the H I column density, radial velocity, and velocity dispersion. Further, position velocity (P-V) slices of the galaxy were taken and three-color images were made using the SDSS G, R, and I, filters for comparison with the moment maps. These slices illustrate the complex neutral gas dynamics in the galaxy and support the interaction hypothesi
Anthropometric Measures of Hadza Forager Children and Juveniles: Implications for Anthropology and Human Biology
Understanding growth trajectories during child development is important for the fields of human biology, public health, medicine, and evolutionary medicine. To date, the majority of current references for childhood development and health are primarily derived from the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC). To ensure a child is developing properly, is equipped with proper nutrition, and will sustain a healthy life through adolescence and adulthood, these measurements and standards are necessary. The current study aims to test whether or not these standards are applicable in non-industrial small-scale societies where differences from western populations include diet composition, environmental pressures, climate, economic activity, mortality rates, and childhood physical activity levels
Direct Detections of Young Stars in Nearby Elliptical Galaxies
Small amounts of star formation in elliptical galaxies are suggested by
several results: surprisingly young ages from optical line indices, cooling
X-ray gas, and mid-IR dust emission. Such star formation has previously been
difficult to directly detect, but using UV Hubble Space Telescope (HST) Wide
Field Camera 3 (WFC3) imaging, we have identified individual young stars and
star clusters in four nearby ellipticals. This technique is orders of magnitude
more sensitive than other methods, allowing detections of star formation to
10^(-5) Msun/yr. Ongoing star formation is detected in all galaxies, including
three ellipticals that have previously exhibited potential signposts of star
forming conditions (NGC 4636, NGC 4697, and NGC 4374), as well as the typical
"red and dead" NGC 3379. The current star formation in our closest targets,
where we are most complete, is between 1-8x10^(-5) Msun/yr. The star formation
history was roughly constant from 0.5-1.5 Gyr (at 3-5x10^(-4) Msun/yr), but
decreased by a factor of several in the past 0.3 Gyr. Most star clusters have a
mass between 10^2 - 10^4 Msun. The specific star formation rates of ~10^(-16)
yr^(-1) (at the present day) or ~10^(-14) yr^(-1) (when averaging over the past
Gyr) imply that a fraction 10^(-8) of the stellar mass is younger than 100 Myr
and 10^(-5) is younger than 1 Gyr, quantifying the level of frosting of recent
star formation over the otherwise passive stellar population. There is no
obvious correlation between either the presence or spatial distribution of
postulated star formation indicators and the star formation we detect.Comment: Accepted for publication in ApJ. 14 pages, 11 figure
Do Aid Agencies Have an Ethical Duty to Comply with Researchers? A Response to Rennie.
Medical AID organisations such as Médecins Sans Frontières receive several requests from individuals and international academic institutions to conduct research at their implementation sites in Africa. Do AID agencies have an ethical duty to comply with research requests? In this paper we respond to the views and constructed theories (albeit unfounded) of one such researcher, whose request to conduct research at one of our sites in the Democratic Republic of Congo was turned down
Operative mortality in resource-limited settings: the experience of Medecins Sans Frontieres in 13 countries.
OBJECTIVE: To determine operative mortality in surgical programs from resource-limited settings. DESIGN, SETTING, AND PARTICIPANTS: A retrospective cohort study of 17 surgical programs in 13 developing countries by 1 humanitarian organization, Médecins Sans Frontières, was performed between January 1, 2001, and December 31, 2008. Participants included patients undergoing surgical procedures. MAIN OUTCOME MEASURE: Operative mortality. Determinants of mortality were modeled using logistic regression. RESULTS: Between 2001 and 2008, 19,643 procedures were performed on 18,653 patients. Among these, 8329 procedures (42%) were emergent; 7933 (40%) were for obstetric-related pathology procedures and 2767 (14%) were trauma related. Operative mortality was 0.2% (31 deaths) and was associated with programs in conflict settings (adjusted odds ratio [AOR] = 4.6; P = .001), procedures performed under emergency conditions (AOR = 20.1; P = .004), abdominal surgical procedures (AOR = 3.4; P = .003), hysterectomy (AOR = 12.3; P = .001), and American Society of Anesthesiologists classifications of 3 to 5 (AOR = 20.2; P < .001). CONCLUSIONS: Surgical care can be provided safely in resource-limited settings with appropriate minimum standards and protocols. Studies on the burden of surgical disease in these populations are needed to improve service planning and delivery. Quality improvement programs are needed for the various stakeholders involved in surgical delivery in these settings
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