University of Maryland, Baltimore County

About: University of Maryland, Baltimore County is a education organization based out in Baltimore, Maryland, United States. It is known for research contribution in the topics: Population & Aerosol. The organization has 8749 authors who have published 20843 publications receiving 795706 citations. The organization is also known as: UMBC.

The Fermi-LAT High-Latitude Survey: Source Count Distributions and the Origin of the Extragalactic Diffuse Background

Abstract: This is the first of a series of papers aimed at characterizing the populations detected in the high-latitude sky of the {\it Fermi}-LAT survey. In this work we focus on the intrinsic spectral and flux properties of the source sample. We show that when selection effects are properly taken into account, {\it Fermi} sources are on average steeper than previously found (e.g. in the bright source list) with an average photon index of 2.40$\pm0.02$ over the entire 0.1--100\,GeV energy band. We confirm that FSRQs have steeper spectra than BL Lac objects with an average index of 2.48$\pm0.02$ versus 2.18$\pm0.02$. Using several methods we build the deepest source count distribution at GeV energies deriving that the intrinsic source (i.e. blazar) surface density at F$_{100}\geq10^{-9}$\,ph cm$^{-2}$ s$^{-1}$ is 0.12$^{+0.03}_{-0.02}$\,deg$^{-2}$. The integration of the source count distribution yields that point sources contribute 16$(\pm1.8)$\,\% ($\pm$7\,\% systematic uncertainty) of the GeV isotropic diffuse background. At the fluxes currently reached by LAT we can rule out the hypothesis that point-like sources (i.e. blazars) produce a larger fraction of the diffuse emission.

Increased atmospheric ammonia over the world's major agricultural areas detected from space.

Abstract: This study provides evidence of substantial increases in atmospheric ammonia (NH3) concentrations (14-year) over several of the worlds major agricultural regions, using recently available retrievals from the Atmospheric Infrared Sounder (AIRS) aboard NASA's Aqua satellite. The main sources of atmospheric NH3 are farming and animal husbandry involving reactive nitrogen ultimately derived from fertilizer use; rates of emission are also sensitive to climate change. Significant increasing trends are seen over the US (2.61% yr-1), the European Union (EU) (1.83% yr-1), and China (2.27% yr-1). Over the EU, the trend results from decreased scavenging by acid aerosols. Over the US, the increase results from a combination of decreased chemical loss and increased soil temperatures. Over China, decreased chemical loss, increasing temperatures, and increased fertilizer use all play a role. Over South Asia, increased NH3 emissions are masked by increased SO2 and NOx emissions, leading to increased aerosol loading and adverse health effects.

Developing knowledge management metrics for measuring intellectual capital

Abstract: Measuring intellectual capital is a growing area of interest in the knowledge management field. Metrics are being developed and applied by some organizations, but there needs to be more research throughout the international community to better define these measures. One limitation of the current measures is that they do not necessarily address the “knowledge level” and the types of value‐added knowledge that individuals obtain. This paper takes a look at the current measures, discusses some possible limitations, and suggests some additional measures that could be used in the intellectual capital area to complement existing measures.

Functional recovery and medical costs of trauma: an analysis by type and severity of injury.

Abstract: This study was designed to delineate the factors that influence the extent and rate of recovery as related to the characteristics and duration of functional limitations resulting from trauma. The study population was 597 surviving trauma patients aged 16-45 years from two trauma centers in a single state system which follow similar care protocols, and included patients with extremity, abdomen, thorax, brain, and spinal cord injuries. Of 479 trauma patients (80% of the total) who were followed for a full year, 57% had no activity restrictions, 16% had some limitation with either a major or minor physical activity, but did not have any difficulty with mobility or self care, and 27% were limited in either mobility or one of the five basic self-care activities. Further analyses show that of the 262 individuals who were working full-time before the injury, 57% had actually returned to full-time employment within the year. Factors in addition to type and severity of trauma that influence return to work were higher educational level, white collar employment, higher preinjury income, and the presence of supportive individuals among family or friends. Recovery as defined by functional status and return to full-time work is analyzed by body region and severity of the principal injury sustained.

Detection of gamma-ray emission from the starburst galaxies m82 and ngc 253 with the large area telescope on fermi

Abstract: We report the detection of high-energy gamma-ray emission from two starburst galaxies using data obtained with the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. Steady point-like emission above 200 MeV has been detected at significance levels of 6.8 sigma and 4.8 sigma respectively, from sources positionally coincident with locations of the starburst galaxies M82 and NGC 253. The total fluxes of the sources are consistent with gamma-ray emission originating from the interaction of cosmic rays with local interstellar gas and radiation fields and constitute evidence for a link between massive star formation and gamma-ray emission in star-forming galaxies.