34 research outputs found
Health Disparities Between Appalachian and Non-Appalachian Counties in Virginia USA
The examination of health disparities among people within Appalachian counties compared to people living in other counties is needed to find ways to strategically target improvements in community health in the United States of America (USA). Methods: A telephone survey of a random sample of adults living in households within communities of all counties of the state of Virginia (VA) in the USA was conducted. Findings: Health status was poorer among those in communities within Appalachian counties in VA and health insurance did not make a difference. Health perception was significantly worse in residents within communities in Appalachian counties compared to non-Appalachian community residents (30.5 vs. 17.4% rated their health status as poor/fair), and was worse even among those with no chronic diseases. Within communities in Appalachian counties, black residents report significantly better health perception than do white residents. Conclusion: Residents living in communities in Appalachian counties in VA are not receiving adequate health care, even among those with health insurance. More research with a larger ethnic minority sample is needed to investigate the racial/ethnic disparities in self-reported health and health care utilization within communities
First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way
We present the first Event Horizon Telescope (EHT) observations of Sagittarius A* (Sgr A*), the Galactic center source associated with a supermassive black hole. These observations were conducted in 2017 using a global interferometric array of eight telescopes operating at a wavelength of lambda = 1.3 mm. The EHT data resolve a compact emission region with intrahour variability. A variety of imaging and modeling analyses all support an image that is dominated by a bright, thick ring with a diameter of 51.8 +/- 2.3 mu as (68% credible interval). The ring has modest azimuthal brightness asymmetry and a comparatively dim interior. Using a large suite of numerical simulations, we demonstrate that the EHT images of Sgr A* are consistent with the expected appearance of a Kerr black hole with mass similar to 4 x 10(6) M (circle dot), which is inferred to exist at this location based on previous infrared observations of individual stellar orbits, as well as maser proper-motion studies. Our model comparisons disfavor scenarios where the black hole is viewed at high inclination (i > 50 degrees), as well as nonspinning black holes and those with retrograde accretion disks. Our results provide direct evidence for the presence of a supermassive black hole at the center of the Milky Way, and for the first time we connect the predictions from dynamical measurements of stellar orbits on scales of 10(3)-10(5) gravitational radii to event-horizon-scale images and variability. Furthermore, a comparison with the EHT results for the supermassive black hole M87* shows consistency with the predictions of general relativity spanning over three orders of magnitude in central mass
Polymer collapse in miscible good solvents is a generic phenomenon driven by preferential adsorption
Water and alcohol, such as methanol or ethanol, are miscible and, individually, good solvents for poly(N-isopropylacrylamide) (PNIPAm), but this polymer precipitates in water–alcohol mixtures. The intriguing behaviour of solvent mixtures that cannot dissolve a given polymer or a given protein, while the same macromolecule dissolves well in each of the cosolvents, is called cononsolvency. It is a widespread phenomenon, relevant for many formulation steps in the physicochemical and pharmaceutical industry, that is usually explained by invoking specific chemical details of the mixtures: as such, it has so far eluded any generic explanation. Here, by using a combination of simulations and theory, we present a simple and universal treatment that requires only the preferential interaction of one of the cosolvents with the polymer. The results show striking quantitative agreement with experiments and chemically specific simulations, opening a new perspective towards an operational understanding of macromolecular solubility
When Authoritarian Leaders Outperform Transformational Leaders: Firm Performance in a Harsh Economic Environment
We investigate what leadership behaviors drive firm performance in harsh economic environments. Based on data collected from 102 independent subsidiaries of a telecommunications corporation located in 102 counties in China, we found that transformational leadership was not related to subsequent 4-month and 1-year revenue growth, irrespective of the level of the county’s economic resource munificence, which is defined as the level of the region’s overall level of economic activities and its consumption capacity. We also found, however, that authoritarian leadership was positively related to subsequent revenue growth when economic munificence was low but negatively related to revenue growth when economic munificence was high. Based on these results, we propose the theoretical development of the functionality of authoritarian leadership in future research.Department of Management and Marketin
