Analysis of the genus Larrea: Molecular systematics and polyploidy

The evolutionary and biogeographic history of the genus Larrea was assessed by determining patterns of genetic variation in chloroplast DNA, nuclear ribosomal internal transcribed spacer (ITS1) DNA, and temporal and spatial distributions of the three geographically distinct polyploids of Larrea tridentata. The phylogenetic relationships, based on the chloroplast DNA (cpDNA) restriction site analysis, were congruent with morphological studies. Cytoplasmic gene flow was postulated to account for identical haplotypes being shared between L. nitida and L. cuneifolia from South America, with L. nitida as the putative maternal donor. Two distinct cpDNA haplotypes were found in North American L. tridentata, and one of these haplotypes was also found in South American L. divaricata. Low levels of variation were detected throughout the genus, perhaps as a result of extremely long generation times or recent diversification. ITS1 sequences within the genus Larrea are highly variable within individuals as well as species, indicating that concerted evolution has failed to homogenize repeats within an individual. However, intermediacy of concerted evolution was present within the genus where some phylogenetic relationships were supported. This intermediacy may be a result of rapid diversification, polyploidy, introgression and/or long generation time. Finally, ploidy levels within the southwestern deserts were inferred using guard cell size and mean guard cell area was significantly different among all three deserts, but the boundaries of the ploidy levels were not distinct. Polyploidy changes across the range of Larrea tridentata since the end of the glacial maximum to present were inferred from measurements of guard cells of leaves preserved in pack rat middens in the warm deserts of North America. Diploids and tetraploids were present in the lower Colorado River Valley 10,000 to 18,000 years before present (yr B.P.), and were replaced with tetraploids 8,100 yr B.P. Hexaploids were present in the Mojave Desert by 6,500 yr B.P

Relationship between perceived and actual quality of data checking

Data quality is critical to reaching correct research conclusions. Researchers attempt to ensure that they have accurate data by checking the data after it has been entered. Previous research has demonstrated that some methods of data checking are better than others, but not all researchers use the best methods. Perhaps researchers continue to use less optimal data checking methods because they mistakenly believe that they are highly accurate. The purpose of this study was to examine the relationship between perceived data quality and actual data quality. A total of 29 participants completed this study. Participants checked that letters and numbers had been entered correctly into the computer using one of three randomly assigned data checking methods. Afterwards, they rated the quality of their data checking method. The sample correlations between perceived and actual data quality were small to moderate and confidence intervals for the population correlations did not include high values. We conclude that the relationship between actual and perceived data quality is not high

A scoping review of social determinants of health curricula in post-graduate medical education

Social determinants of health are responsible for 50% of ill health. The Royal College of Physicians and Surgeons of Canada CanMEDS role of “physician advocate” requires physicians to attain competency in this particular domain, but physician trainees feel this is not well covered in their training programs. This study performed a scoping review of social determinants of health curricula that had been described, implemented and evaluated in post-graduate medical education. A search using MEDLINE(OvidSP) database, with search terms “residency,” ”curriculum,” and “social determinants” with no age, language, and publication date restrictions was done.Researchers identified a total of 12 studies, all from the United States, in internal medicine (n=4), pediatrics (n=4), family medicine (n=2), or multiple (n=2) residency programs. Most curricula (n=8, 67%), were longitudinal, and most contained both patient or community exposure (n=11, 92%) and/or classroom-based components (n=10, 83%). Most (78%) curricula improved participant related outcomes, including exam performance, awareness regarding personal practice, confidence, improved screening for social determinants of health and referral to support services. Program specific outcomes were frequently positive (50%) and included resident satisfaction and high course evaluation scores, high representation of resident and faculty from minority groups, applicability of training to underserviced populations, and improved engagement of marginalized community members. When evaluated, academic outcomes were always positive, and included acceptance of scholarly projects to national conferences, publication of research work, grants earned to support health projects, local or national awards for leadership and community engagement, and curriculum graduates later pursuing related Masters degrees and/or establishing medical practices in underserved areas. Only one study reported a patient-related outcome, with advice provided by health care providers considered by patients to be helpful. Researchers used these results to design recommendations for creation of a post-graduate curriculum to address social determinants of health were provided

The Shape of LITTLE THINGS Dwarf Galaxies DDO 46 and DDO 168: Understanding the stellar and gas kinematics

We present the stellar and gas kinematics of DDO 46 and DDO 168 from the LITTLE THINGS survey and determine their respective Vmax/sigma_z,0 values. We used the KPNO's 4-meter telescope with the Echelle spectrograph as a long-slit spectrograph. We acquired spectra of DDO 168 along four position angles by placing the slit over the morphological major and minor axes and two intermediate position angles. However, due to poor weather conditions during our observing run for DDO 46, we were able to extract only one useful data point from the morphological major axis. We determined a central stellar velocity dispersion perpendicular to the disk, sigma_z,0, of 13.5+/-8 km/s for DDO 46 and of 10.7+/-2.9 km/s for DDO 168. We then derived the maximum rotation speed in both galaxies using the LITTLE THINGS HI data. We separated bulk motions from non-circular motions using a double Gaussian decomposition technique and applied a tilted-ring model to the bulk velocity field. We corrected the observed HI rotation speeds for asymmetric drift and found a maximum velocity, Vmax, of 77.4 +/- 3.7 and 67.4 +/- 4.0 km/s for DDO 46 and DDO 168, respectively. Thus, we derived a kinematic measure, Vmax/sigma_z,0, of 5.7 +/- 0.6 for DDO 46 and 6.3 +/- 0.3 for DDO 168. Comparing these values to ones determined for spiral galaxies, we find that DDO 46 and DDO 168 have Vmax/sigma_z,0 values indicative of thin disks, which is in contrast to minor-to-major axis ratio studies

The Stellar and Gas Kinematics of the LITTLE THINGS Dwarf Irregular Galaxy NGC 1569

In order to understand the formation and evolution of dIm galaxies, one needs to understand their three-dimensional structure. We present measurements of the stellar velocity dispersion in NGC 1569, a nearby post-starburst dIm galaxy. The stellar vertical velocity dispersion, $\sigma_{\rm z}$, coupled with the maximum rotational velocity derived from \ion{H}{1} observations, $V_{\rm max}$, gives a measure of how kinematically hot the galaxy is, and, therefore, indicates its structure. We conclude that the stars in NGC 1569 are in a thick disk with a $V_{\rm max} / \sigma_{\rm z}$ = 2.4 $\pm$ 0.7. In addition to the structure, we analyze the ionized gas kinematics from \ion{O}{3} observations along the morphological major axis. These data show evidence for outflow from the inner starburst region and a potential expanding shell near supermassive star cluster (SSC) A. When compared to the stellar kinematics, the velocity dispersion of the stars increase in the region of SSC A supporting the hypothesis of an expanding shell. The stellar kinematics closely follow the motion of the gas. Analysis of high resolution \ion{H}{1} data clearly reveals the presence of an \ion{H}{1} cloud that appears to be impacting the eastern edge of NGC 1569. Also, an ultra-dense \ion{H}{1} cloud can be seen extending to the west of the impacting \ion{H}{1} cloud. This dense cloud is likely the remains of a dense \ion{H}{1} bridge that extended through what is now the central starburst area. The impacting \ion{H}{1} cloud was the catalyst for the starburst, thus turning the dense gas into stars over a short timescale, $\sim$ 1 Gyr. We performed a careful study of the spectral energy distribution using infrared, optical, and ultraviolet photometry producing a state-of-the-art mass model for the stellar disk. This mass modeling shows that stars dominate the gravitational potential in the inner 1 kpc.Comment: 49 pages, 25 figures, accepted in A