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.

Multiangle implementation of atmospheric correction (MAIAC): 1. Radiative transfer basis and look-up tables

Abstract: [1] This paper describes a radiative transfer basis of the algorithm MAIAC which performs simultaneous retrievals of atmospheric aerosol and bidirectional surface reflectance from the Moderate Resolution Imaging Spectroradiometer (MODIS). The retrievals are based on an accurate semianalytical solution for the top-of-atmosphere reflectance expressed as an explicit function of three parameters of the Ross–Thick Li–Sparse model of surface bidirectional reflectance. This solution depends on certain functions of atmospheric properties and geometry which are precomputed in the look-up table (LUT). This paper further considers correction of the LUT functions for variations of surface pressure/height and of atmospheric water vapor, which is a common task in the operational remote sensing. It introduces a new analytical method for the water vapor correction of the multiple-scattering path radiance. It also summarizes the few basic principles that provide a high efficiency and accuracy of the LUT-based radiative transfer for the aerosol/surface retrievals and optimize the size of LUT. For example, the single-scattering path radiance is calculated analytically for a given surface pressure and atmospheric water vapor. The same is true for the direct surface-reflected radiance, which along with the single-scattering path radiance largely defines the angular dependence of measurements. For these calculations, the aerosol phase functions and kernels of the surface bidirectional reflectance model are precalculated at a high angular resolution. The other radiative transfer functions depend rather smoothly on angles because of multiple scattering and can be calculated at coarser angular resolution to reduce the LUT size. At the same time, this resolution should be high enough to use the nearest neighbor geometry angles to avoid costly three-dimensional interpolation. The pressure correction is implemented via linear interpolation between two LUTs computed for the standard and reduced pressure levels. A linear mixture and a modified linear mixture methods are used to represent different aerosol types in the aerosol/surface retrievals from several base models of the fine and coarse aerosol fractions. In summary, the developed LUT algorithm allows fast high-accuracy simulations of the outgoing radiance with full variability of the atmospheric and surface bidirectional reflectance properties for the aerosol/surface remote sensing.

Lateral diffusion in phospholipid multibilayers measured by fluorescence recovery after photobleaching

Abstract: The method of fluorescence recovery after photobleaching has been used to measure the temperature dependence of the lateral diffusion coefficients (D) of two fluorescent lipid analogues in phospholipid multibilayers of various compositions. The probes employed were 3,3-dioctadecyloxocarbocyanine (diO-C18(3) and N-4-nitrobenz-2-oxa-1,3-diazole phosphatidylethanolamine (NBD-PE). In fluid egg phosphatidylcholine multibilayers at 25 degrees C, D was about 4 X 10(-8) cm2/s for NBD-PE and 1.5 X 10(-7) cm2/s for diO-C18(3) and was moderately temperature dependent (2-fold change over 10 degrees C). Equimolar cholesterol reduced D for NBD-PE in these multibilayers by a factor of 2. A greater than 100-fold decrease in D was detected in dimyristoylphosphatidylcholine multibilayers at approximately 23 degree C, which coincides with the gel-to-liquid-crystalline transition temperature, Tm (D 5 X 10(-8) cm2/s at T greater than Tm to D less than 5 X 10(-10) cm2/s at T less than Tm). Equimolar cholesterol abolished this transition behavior, raising D below Tm and decreasing D above Tm. These results confirm and extend previous studies of lateral diffusion employing magnetic resonance and other optical techniques and give additional confidence in the fluorescence methods.

Intersectionality in Quantitative Psychological Research: I. Theoretical and Epistemological Issues

Abstract: Intersectionality has become something of a buzzword in psychology and is well-known in feminist writings throughout the social sciences. Across diverse definitions of intersectionality, we find three common assumptions: (1) There is a recognition that all people are characterized simultaneously by multiple social categories and that these categories are interconnected or intertwined. (2) Embedded within each of these categories is a dimension of inequality or power. (3) These categories are properties of the individual as well as characteristics of the social context inhabited by those individuals; as such, categories and their significance may be fluid and dynamic. Understanding intersectionality as an approach and critical theory, rather than as a falsifiable theory, we consider its potential within research using quantitative methods. We discuss positivism, social constructionism, and standpoint epistemology in order to examine the implications of these epistemologies for research methods and to explo...

The cost of relapse and the predictors of relapse in the treatment of schizophrenia.

Abstract: To assess the direct cost of relapse and the predictors of relapse during the treatment of patients with schizophrenia in the United States. Data were drawn from a prospective, observational, noninterventional study of schizophrenia in the United States (US-SCAP) conducted between 7/1997 and 9/2003. Patients with and without relapse in the prior 6 months were compared on total direct mental health costs and cost components in the following year using propensity score matching method. Baseline predictors of subsequent relapse were also assessed. Of 1,557 participants with eligible data, 310 (20%) relapsed during the 6 months prior to the 1-year study period. Costs for patients with prior relapse were about 3 times the costs for patients without prior relapse. Relapse was associated with higher costs for inpatient services as well as for outpatient services and medication. Patients with prior relapse were younger and had onset of illness at earlier ages, poorer medication adherence, more severe symptoms, a higher prevalence of substance use disorder, and worse functional status. Inpatient costs for patients with a relapse during both the prior 6 months and the follow-up year were 5 times the costs for patients with relapse during the follow-up year only. Prior relapse was a robust predictor of subsequent relapse, above and beyond information about patients' functioning and symptom levels. Despite the historical decline in utilization of psychiatric inpatient services, relapse remains an important predictor of subsequent relapse and treatment costs for persons with schizophrenia.