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.

Resilience Among Urban African American Male Adolescents: A Study of the Protective Effects of Sociopolitical Control on Their Mental Health

Abstract: Resilience refers to the notion that some people succeed in the face of adversity. In a risk-protective model of resilience, a protective factor interacts with a risk factor to mitigate the occurrence of a negative outcome. This study tested longitudinally the protective effects of sociopolitical control on the link between helplessness and mental health. The study included 172 urban, male, African American adolescents, who were interviewed twice, 6 months apart. Sociopolitical control was defined as the beliefs about one's capabilities and efficacy in social and political systems. Two mental health outcomes were examined—psychological symptoms and self-esteem. Regression analyses to predict psychological symptoms and self-esteem over time were conducted. High levels of sociopolitical control were found to limit the negative consequences of helplessness on mental health. The results suggest that sociopolitical control may help to protect youths from the negative consequences of feelings of helplessness. Implications for prevention strategies are discussed.

A Complex Generalized Gaussian Distribution— Characterization, Generation, and Estimation

Abstract: The generalized Gaussian distribution (GGD) provides a flexible and suitable tool for data modeling and simulation, however the characterization of the complex-valued GGD, in particular generation of samples from a complex GGD have not been well defined in the literature. In this correspondence, we provide a thorough presentation of the complex-valued GGD by: (i) constructing the probability density function (pdf); (ii) defining a procedure for generating random numbers from the complex-valued GGD; and (iii) implementing a maximum likelihood estimation (MLE) procedure for the shape and covariance parameters in the complex domain. We quantify the performance of the MLE with simulations and actual radar data.

Components of hostility and the severity of coronary artery disease.

Abstract: Previous research has linked various measures of hostility to the prevalence and incidence of coronary heart disease (CHD). The present study sought to determine whether some dimensions of hostility are differentially related to angiographically documented severity of coronary artery disease (CAD). Specifically, a hostility measure that correlates with indices of neuroticism was compared with a hostility measure unrelated to neurotic tendencies. For patients 60 years and younger, results were significant, revealing that neurotic hostility was inversely associated with severity of CAD whereas nonneurotic hostility scores were positively related to extent of disease. Overall hostility scores derived from the combination of the two kinds of hostility measures were unrelated to CAD severity. Results suggest that the multidimensional nature of the hostility construct should be appreciated in attempts to associate measures of hostility with manifestations of CHD.

Degradation of Ofloxacin by Perylene Diimide Supramolecular Nanofiber Sunlight-Driven Photocatalysis.

Abstract: This study describes a promising sunlight-driven photocatalyst for the treatment of ofloxacin and other fluoroquinolone antibiotics in water and wastewater. Perylene diimide (PDI) supramolecular nanofibers, which absorb a broad spectrum of sunlight, were prepared via a facile acidification polymerization protocol. Under natural sunlight, the PDI photocatalysts achieved rapid treatment of fluoroquinolone antibiotics, including ciprofloxacin, enrofloxacin, norfloxacin, and ofloxacin. The fastest degradation was observed for ofloxacin, which had a half-life of 2.08 min for the investigated conditions. Various light sources emitting in the UV-vis spectrum were tested, and blue light was found to exhibit the fastest ofloxacin transformation kinetics due to the strong absorption by the PDI catalyst. Reactive species, namely, h+, 1O2, and O2•-, comprised the primary photocatalytic mechanisms for ofloxacin degradation. Frontier electron density calculations and mass spectrometry were used to verify the major degradation pathways of ofloxacin by the PDI-sunlight photocatalytic system and identify the transformation products of ofloxacin, respectively. Degradation mainly occurred through demethylation at the piperazine ring, ketone formation at the morpholine moiety, and aldehyde reaction at the piperazinyl group. An overall mechanism was proposed for ofloxacin degradation in the PDI-sunlight photocatalytic system, and the effects of water quality constituents were examined to determine performance in real water/wastewater systems. Ultimately, the aggregate results from this study highlight the suitability of the PDI-sunlight photocatalytic system to treat antibiotics in real water and wastewater systems.

Agent-organized networks for dynamic team formation

Abstract: Many multi-agent systems consist of a complex network of autonomous yet interdependent agents. Examples of such networked multi-agent systems include supply chains and sensor networks. In these systems, agents have a select set of other agents with whom they interact based on environmental knowledge, cognitive capabilities, resource limitations, and communications constraints. Previous findings have demonstrated that the structure of the artificial social network governing the agent interactions is strongly correlated with organizational performance. As multi-agent systems are typically embedded in dynamic environments, we wish to develop distributed, on-line network adaptation mechanisms for discovering effective network structures. Therefore, within the context of dynamic team formation, we propose several strategies for agent-organized networks (AONs) and evaluate their effectiveness for increasing organizational performance.