University of Illinois at Chicago

About: University of Illinois at Chicago is a education organization based out in Chicago, Illinois, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 57071 authors who have published 110536 publications receiving 4264936 citations.

Hydrocarbon-Degrading Bacteria and the Bacterial Community Response in Gulf of Mexico Beach Sands Impacted by the Deepwater Horizon Oil Spill

Abstract: A significant portion of oil from the recent Deepwater Horizon (DH) oil spill in the Gulf of Mexico was transported to the shoreline, where it may have severe ecological and economic consequences. The objectives of this study were (i) to identify and characterize predominant oil-degrading taxa that may be used as model hydrocarbon degraders or as microbial indicators of contamination and (ii) to characterize the in situ response of indigenous bacterial communities to oil contamination in beach ecosystems. This study was conducted at municipal Pensacola Beach, FL, where chemical analysis revealed weathered oil petroleum hydrocarbon (C 8 to C40) concentrations ranging from 3.1 to 4,500 mg kg 1 in beach sands. A total of 24 bacterial strains from 14 genera were isolated from oiled beach sands and confirmed as oil-degrading microorganisms. Isolated bacterial strains were primarily Gammaproteobacteria, including representatives of genera with known oil degraders (Alcanivorax, Marinobacter, Pseudomonas, and Acinetobacter). Sequence libraries generated from oiled sands revealed phylotypes that showed high sequence identity (up to 99%) to rRNA gene sequences from the oil-degrading bacterial isolates. The abundance of bacterial SSU rRNA gene sequences was 10-fold higher in oiled (0.44 10 7 to 10.2 10 7 copies g 1 ) versus clean (0.024 10 7 to 1.4 10 7 copies g 1 ) sand. Community analysis revealed a distinct response to oil contamination, and SSU rRNA gene abundance derived from the genus Alcanivorax showed the largest increase in relative abundance in contaminated samples. We conclude that oil contamination from the DH spill had a profound impact on the abundance and community composition of indigenous bacteria in Gulf beach sands, and our evidence points to members of the Gammaproteobacteria (Alcanivorax, Marinobacter) and Alphaproteobacteria (Rhodobacteraceae) as key players in oil degradation there. The blowout of the Deepwater Horizon (DH) drilling rig resulted in the world’s largest accidental release of oil into the ocean in recorded history. The equivalent volume of approximately 4.9 million barrels of light crude oil were discharged into the Gulf of Mexico from April to July 2010 (OSAT/ NOAA report [56] and oil budget calculator [43]), and the total hydrocarbon discharge was 40% higher if gaseous hydrocarbons are included (34). A large amount of the discharged oil was transported to the surface and reached the shoreline. Although cleanup efforts have remained aggressive, a substantial portion of the oil remains trapped in coastal ecosystems, especially in benthic areas. Permeable sandy sediments cover large areas of the seafloor in the Gulf of Mexico, including beach ecosystems. Marine sands act as efficient biocatalytic filters that play an important role in the biogeochemical cycles of carbon and nutrients in

Flexible Multibody Dynamics: Review of Past and Recent Developments

Abstract: In this paper, a review of past and recent developments in the dynamics of flexible multibody systems is presented. The objective is to review some of the basic approaches used in the computer aided kinematic and dynamic analysis of flexible mechanical systems, and to identify future directions in this research area. Among the formulations reviewed in this paper are the floating frame of reference formulation, the finite element incremental methods, large rotation vector formulations, the finite segment method, and the linear theory of elastodynamics. Linearization of the flexible multibody equations that results from the use of the incremental finite element formulations is discussed. Because of space limitations, it is impossible to list all the contributions made in this important area. The reader, however, can find more references by consulting the list of articles and books cited at the end of the paper. Furthermore, the numerical procedures used for solving the differential and algebraic equations of flexible multibody systems are not discussed in this paper since these procedures are similar to the techniques used in rigid body dynamics. More details about these numerical procedures as well as the roots and perspectives of multibody system dynamics are discussed in a companion review by Schiehlen [79]. Future research areas in flexible multibody dynamics are identified as establishing the relationship between different formulations, contact and impact dynamics, control-structure interaction, use of modal identification and experimental methods in flexible multibody simulations, application of flexible multibody techniques to computer graphics, numerical issues, and large deformation problem. Establishing the relationship between different flexible multibody formulations is an important issue since there is a need to clearly define the assumptions and approximations underlying each formulation. This will allow us to establish guidelines and criteria that define the limitations of each approach used in flexible multibody dynamics. This task can now be accomplished by using the “absolute nodal coordinate formulation” which was recently introduced for the large deformation analysis of flexible multibody systems.

Developing instruments for cross-cultural psychiatric research.

Abstract: The growth of cross-cultural psychiatry is now occurring at a time when psychiatry in general is emphasizing diagnostic clarity and the use of quantifiable and reliable methods of collecting clinical and research data. It is now imperative that cross-cultural psychiatry also examine its methods for developing instruments for use in cross-cultural research. This paper outlines a method for developing instruments designed in one culture for use in a second, and particular attention is given to cross-cultural validity or equivalence. Five types of equivalence are enumerated and defined: content, semantic, technical, criterion, and conceptual equivalence. These concepts are illustrated by examples from the authors' experience in research on internal migrants in Peru.

Scientific Utopia: II - Restructuring Incentives and Practices to Promote Truth Over Publishability

Abstract: An academic scientist’s professional success depends on publishing. Publishing norms emphasize novel, positive results. As such, disciplinary incentives encourage design, analysis, and reporting decisions that elicit positive results and ignore negative results. Prior reports demonstrate how these incentives inflate the rate of false effects in published science. When incentives favor novelty over replication, false results persist in the literature unchallenged, reducing efficiency in knowledge accumulation. Previous suggestions to address this problem are unlikely to be effective. For example, a journal of negative results publishes otherwise unpublishable reports. This enshrines the low status of the journal and its content. The persistence of false findings can be meliorated with strategies that make the fundamental but abstract accuracy motive – getting it right – competitive with the more tangible and concrete incentive – getting it published. We develop strategies for improving scientific practices and knowledge accumulation that account for ordinary human motivations and self-serving biases.