Emergence of Stimulus Equivalence and Topography-Based Responding Following Lecture Instruction

The present study examined the emergence of stimulus equivalence using both selection-based and topography-based tests following a lecture or control condition. This study also evaluated generalization to novel stimuli in both selection-based and topography-based response formats, and evaluated the social validity of the instructional procedure. Twenty undergraduate students who were at least 18 years of age were assigned to a lecture or control condition. Participants in the lecture condition were exposed to a lecture on the topic of generalization. Participants in the control condition watched the video Martin Seligman: The New Era of Positive Psychology that did not relate to the content of the tests. Participants were given multiple choice pre- and post-tests, intraverbal pre- and post-tests, and emergent relation pre- and post-tests. When selection-based tests were compared to topography-based tests, neither group performed significantly better on one type of test or the other. As for generalization, both the lecture and control groups showed an increase in correct responding. Since both groups had an increase in correct responding, the generalization that occurred was likely due to a testing effect and not the specific condition that the participants were exposed. Participants in this study moderately preferred the instructional format

Triclosan Enriches for \u3cem\u3eDehalococcoides\u3c/em\u3e-like \u3cem\u3eChloroflexi\u3c/em\u3e in Anaerobic Soil at Environmentally Relevant Concentrations

Triclosan is an antimicrobial agent that is discharged to soils with land-applied wastewater biosolids, is persistent under anaerobic conditions, and yet its impact on anaerobic microbial communities in soils is largely unknown. We hypothesized that triclosan enriches for Dehalococcoides-like Chloroflexi because these bacteria respire organochlorides and are likely less sensitive, relative to other bacteria, to the antimicrobial effects of triclosan. Triplicate anaerobic soil microcosms were seeded with agricultural soil, which was not previously exposed to triclosan, and were amended with 1 mg kg−1 of triclosan. Triplicate control microcosms did not receive triclosan, and the experiment was run for 618 days. The overall bacterial community (assessed by automated ribosomal intergenic spacer analysis and denaturing gradient gel electrophoresis) was not impacted by triclosan; however, the abundance of Dehalococcoides-like Chloroflexi 16S rRNA genes (determined by qPCR) increased 20-fold with triclosan amendment compared with a fivefold increase without triclosan. This work demonstrates that triclosan impacts anaerobic soil communities at environmentally relevant levels

A common and previously unknown ecological niche: the halorespiration of natural organochlorines in terrestrial soil and sediment

University of Minnesota Ph.D. dissertation. December 2011. Major: Art History. Advisor: Paige J. Novak. 1 computer file (PDF)x, 163 pages, appendices A-D.The phylum Chloroflexi contains several isolated bacteria that have been found to dechlorinate a diverse array of halogenated anthropogenic chemicals. These bacteria use organohalogens, such as polychlorinated biphenyls and trichloroethene, as their terminal electron acceptors and are called halorespirers. While the distribution and role of halorespiring Chloroflexi, as well as halorespirers in other phyla such as the Firmicutes, have been relatively well characterized in contaminated systems and laboratory cultures, their distribution and role in uncontaminated terrestrial environments, where abundant natural organohalogens could function as potential electron acceptors, has not been studied. This dissertation focuses on the distribution and role of halorespiring Chloroflexi in uncontaminated environments and investigates the ability of natural organochlorines to serve as terminal electron acceptors for halorespiring organisms

Abundance and Diversity of Organohalide-Respiring Bacteria in Lake Sediments Across a Geographical Sulfur Gradient

Across the U.S. Upper Midwest, a natural geographical sulfate gradient exists in lakes. Sediment grab samples and cores were taken to explore whether this sulfur gradient impacted organohalide-respiring Chloroflexi in lake sediments. Putative organohalide-respiring Chloroflexi were detected in 67 of 68 samples by quantitative polymerase chain reaction. Their quantities ranged from 3.5 × 104 to 8.4 × 1010 copies 16S rRNA genes g−1 dry sediment and increased in number from west to east, whereas lake sulfate concentrations decreased along this west-to-east transect. A terminal restriction fragment length polymorphism (TRFLP) method was used to corroborate this inverse relationship, with sediment samples from lower sulfate lakes containing both a higher number of terminal restriction fragments (TRFs) belonging to the organohalide-respiring Dehalococcoidetes, and a greater percentage of the TRFLP amplification made up by Dehalococcoidetes members. Statistical analyses showed that dissolved sulfur in the porewater, measured as sulfate after oxidation, appeared to have a negative impact on the total number of putative organohalide-respiring Chloroflexi, the number of Dehalococcoidetes TRFs, and the percentage of the TRFLP amplification made up by Dehalococcoidetes. These findings point to dissolved sulfur, presumably present as reduced sulfur species, as a potentially controlling factor in the natural cycling of chlorine, and perhaps as a result, the natural cycling of some carbon as well

Response of sediment bacterial community to triclosan in subtropical freshwater benthic microcosms

The response of sediment bacterial communities in subtropical freshwater benthic microcosms to sediment-associated triclosan (TCS; 28 d exposure) was analysed using Illumina high-throughput sequencing. This study highlights the interactive effects of TCS and the presence of benthic macroinvertebrates (Limnodrilus hoffmeisteri and Viviparidae bellamya) on sediment bacterial communities. Our results show that TCS alone significantly altered the taxonomic composition and decreased alpha diversity of sediment bacterial communities at concentrations ≥80 μg TCS/g dry weight (dw) sediment (sed). Regarding dominant phyla, TCS significantly reduced the relative abundance of Bacteroidetes and Firmicutes at these concentrations, whereas the relative abundance of Chloroflexi and Cyanobacteria increased. In the presence of benthic macroinvertebrates, the sediment bacterial community was affected by 8 μg TCS/g dw sed as well. However, the presence of benthic macroinvertebrates did not cause measurable changes to bacterial community in unspiked (i.e., control) sediment. These results indicate that TCS alone would not alter the sediment bacterial community at environmentally relevant concentrations (up till 8 μg/g dw sed), but may have an effect in combination with the presence of benthic macroinvertebrates. Therefore, we recommend to include benthic macroinvertebrates when assessing the response of sediment bacterial communities during exposure to environmental stress such as organic contaminants.</p

GovLoop, réseau social des fonctionnaires américains

Tout commence en 2003, lorsque Steve Ressler, membre de la génération Y, âgé de 24 ans, obtient son master de sociologie à l’université de Pennsylvanie avec un sujet de mémoire relatif aux réseaux terroristes. Recruté par le ministère de la Sécurité intérieure, nouvellement institué par le gouvernement américain, le jeune diplômé s’installe à Washington. Steve Ressler et sa demi-sœur, Megan Quinn, qui appartient, elle aussi, à la génération Y, découvrent alors des milieux professionnels où le..

Performance Analysis of Squad Car Lighting, Retro-reflective Markings, and Paint Treatments to Improve Safety at Roadside Traffic Stops

In the United States, more police officers are killed in collisions at roadside stops than through felonious acts. Causal factors that affect police safety at roadside stops include officer conspicuity, squad conspicuity, weather conditions, and the attention and fatigue level of the traveling public. Described herein is a research project that provides insight and guidelines that may ultimately improve officer safety at roadside stops. The project is designed to modify an existing sensor-based traffic monitoring system so that it serves as a test bed to evaluate the retro-reflector, lighting, and paint treatments of an emergency vehicle to determine whether particular combinations produce improved “move over” behavior of oncoming traffic. This is done using automated data analysis software built specifically for this project. Tests are performed at a fully instrumented rural intersection. After mimicking a traffic stop where a patrol vehicle is placed at this intersection, the experimenter logs onto a website and enters the time when the test took place. Analysis software draws results from the data. The results are e-mailed to the experimenters, who devise their own test regimes, following the guidelines presented herein, and draw their own conclusions. A second system was built to provide a more portable option for testing in urban areas. This system consists of two freestanding radar boxes with wireless communication, as well as one netbook computer. Test procedures and results are analogous to the original system. Additional calibration is automatically performed to account for the variable position of the radars.Intelligent Vehicles Laboratory, Department of Mechanical Engineering, University of Minnesot

Diversity and Niche of Archaea in Bioremediation

Bioremediation is the use of microorganisms for the degradation or removal of contaminants. Most bioremediation research has focused on processes performed by the domain Bacteria; however, Archaea are known to play important roles in many situations. In extreme conditions, such as halophilic or acidophilic environments, Archaea are well suited for bioremediation. In other conditions, Archaea collaboratively work alongside Bacteria during biodegradation. In this review, the various roles that Archaea have in bioremediation is covered, including halophilic hydrocarbon degradation, acidophilic hydrocarbon degradation, hydrocarbon degradation in nonextreme environments such as soils and oceans, metal remediation, acid mine drainage, and dehalogenation. Research needs are addressed in these areas. Beyond bioremediation, these processes are important for wastewater treatment (particularly industrial wastewater treatment) and help in the understanding of the natural microbial ecology of several Archaea genera