Growth kinetics and competition between Methanosarcina and Methanosaeta in mesophilic anaerobic digestion.

Methanosarcina species with a high maximum specific growth rate (mumax) and high half-saturation coefficient (KS) and Methanosaeta species with a low mumax and low KS are the only known aceticlastic methanogens. Because of Methanosaeta's low KS, the low acetate concentrations in conventional, mesophilic anaerobic digestion yield Methanosaeta dominance. However, Methanosarcina absorbs increases in acetate more efficiently and thus promotes more stable digestion. This paper tests the hypothesis that decreasing digester feeding frequencies can increase Methanosarcina predominance. Two acetate-fed reactors were established at a 17-day solids retention time. One reactor was fed hourly, and one was fed once daily. Microscopic and molecular methods were used to verify that the hourly fed reactor enriched for Methanosaeta, while the daily fed reactor enriched for Methanosarcina. Growth and substrate-use kinetics were measured for each reactor. A digester overload condition was simulated, and the Methanosarcina-enriched reactor was found to perform better than the Methanosaeta-enriched reactor. These findings indicate that Methanosarcina dominance can be achieved with infrequent feedings, leading to more stable digestion.     

Gulf War agents trigger discrete transcriptional changes in human neuronal cells

Reports on Gulf War illness (GWI) implicated the use of the pesticide permethrin (PER), and the insect repellent N,N-diethyl-m-toluamide (DEET), in its etiology, as well as pyridostigmine bromide (PB), which was given as a prophylactic treatment against nerve agent exposure. Using Affymetrix microarrays the genomic response of human neuronal SHSY-5Y cells to 10 days of exposure to these agents was characterized and profiles of gene modulation unique to each treatment were demonstrated. In particular, a significantly greater impact of PER was observed compared to the other treatments. The Ingenuity Pathway Analysis knowledgebase was used to analyze the genomic datasets and attribute functional consequences to the effects of related genes, which were significantly up- or down-regulated in response to different treatments. Canonical pathways shown to be significantly modulated at the genomic level in response to exposure included cellular mechanisms, which might contribute to the clinical presentation in GWI patients and thus be targeted for further investigation as potential targets for therapeutic intervention.     

A New Perspective on Sustainable Soil Remediation—Case Study Suggests Novel Fungal Genera Could Facilitate in situ Biodegradation of Hazardous Contaminants

Deciding upon a cost effective and sustainable method to address soil pollution is a challenge for many remedial project managers. High pressure to quickly achieve cleanup goals pushes for energy‐intensive remedies that rapidly address the contaminants of concern with established technologies, often leaving little room for research and development especially for slower treatment technologies, such as bioremediation, for the more heavily polluted sites. In this case study, new genomic approaches have been leveraged to assess fungal biostimulation potential in soils polluted with particularly persistent hydrophobic contaminants. This new approach provides insights into the genetic functions available at a given site in a way never before possible. In particular, this article presents a case study where next‐generation sequencing has been used to categorize fungi in soils from the Atlantic Wood Industries Superfund site in Portsmouth, Virginia. Data suggest that original attempts to harness fungi for bioremediation may have focused on fungal genera poorly suited to survive under heavily polluted site conditions, and that more targeted approaches relying on native indigenous fungi which are better equipped to survive under site‐specific conditions may be more appropriate. ©2016 Wiley Periodicals, Inc.     

Fish Migration, Dams, and Loss of Ecosystem Services in the Mekong Basin

The past decade has seen increased international recognition of the importance of the services provided by natural ecosystems. It is unclear however whether such international awareness will lead to improved environmental management in many regions. We explore this issue by examining the specific case of fish migration and dams on the Mekong river. We determine that dams on the Mekong mainstem and major tributaries will have a major impact on the basin’s fisheries and the people who depend upon them for food and income. We find no evidence that current moves towards dam construction will stop, and consider two scenarios for the future of the fisheries and other ecosystems of the basin. We conclude that major investment is required in innovative technology to reduce the loss of ecosystem services, and alternative livelihood strategies to cope with the losses that do occur.     

Collisions involving senior drivers: high-risk conditions and locations

OBJECTIVES: To better understand the characteristics of crashes involving senior drivers 65 and older, studies of these crashes were reviewed. METHODS: The review focused primarily on North American studies published since 1990. Studies point to important differences between the crashes of senior drivers and those of younger drivers. RESULTS. Numerous studies have found that senior drivers' crashes are much more likely than crashes of younger drivers to occur at intersections. Senior drivers have particularly high rates of involvement in intersection crashes when they are turning, and even more so when they are turning left. Senior drivers are more likely than younger drivers to have been at fault in these situations, typically because they failed to yield the right-of-way, disregarded the traffic signal, or committed some other traffic violation. Studies also suggest that the extent of overinvolvement of senior drivers in certain types of crashes generally increases with advancing age. CONCLUSIONS. The extent to which the distinctive characteristics of senior drivers' crashes may be due to changing travel patterns associated with aging, or physical or cognitive impairments related to the aging process, is unclear. Further research is needed to understand the pre-crash circumstances of older drivers' intersection crashes.     

The Logical Foundations of Ecological Footprints

An academic debate about ecological footprints has started at last. It was set in motion by a critical article in Ecological Economics, 29(1), 61–72, by Jeroen C.J.M. van den Bergh and Harmen Verbruggen (henceforth B&V). Being ourselves major users of ecological footprints, we disagree with most of the criticisms that B&V level at the concept. In our experience, there are widespread misunderstandings surrounding the methodology of eco-footprinting, so it seems a good time to set out the logical foundations of eco-footprinting for all those who may have an interest in the subject – surely extending beyond the readers of Ecological Economics. Thus our approach will be a general exposition. However, even those who have not read the article by B&V will doubtless benefit from knowing the sort of criticisms which are made against ecological footprints, so we will also attempt to explain and respond to the criticisms raised by B&V.     

The Maintenance of Landscape Health in the Midst of Land Use Change

Land use design that recognizes the landscape attributes that characterize homeostatic health can emphasize them during land use change. The attributes of landscape health are the working mechanisms of all open systems, and can be observed in the homeostatic behavior of forests, deserts and floodplains. These attributes are openness, self-regulation, storage and diversity. The attributes of health comprise criteria for evaluating and guiding land use. To maintain landscape health, land use design can maintain and restore these mechanisms during change of moderate pace and scale.     

Other high-risk factors for young drivers--how graduated licensing does,doesn't,or could address them

PROBLEM: Young drivers, particularly those who are newly licensed, have a very high crash risk. This paper examines the risk factors underlying their high crash rates and assesses the extent to which existing graduated licensing programs address these risks and whether improvements to these programs should be considered. METHOD: Review and synthesis of the literature. RESULTS: The elevated risk among young drivers of being in an injury crash is the result of a number of factors found alone or in combination, such as risky driving, alcohol use, seat belt nonuse, driver distraction, fatigue, and vehicle choice. Nighttime and passenger restrictions, adopted widely in the United States, work by keeping drivers out of hazardous situations rather than by addressing risk factors directly. However, the risk factors remain in play in driving situations not specifically restricted by law. Although other graduated licensing components adopted around the world-more stringent exit tests (i.e., you need to pass a test to move to the next stage), hazard perception tests, and restrictions on speed, vehicle power, and roadway access-make sense based on the identified risk factors, they are not yet supported by research. Should research findings warrant it, consideration should be given to providing guidance to parents about how to keep their beginning drivers safe, including information on vehicle choice. IMPACT ON RESEARCH, PRACTICE, AND POLICY: Researchers should continue to monitor and to evaluate innovative approaches to reduce the crash risk of young drivers. The effectiveness of new approaches should be established before adoption on a wider scale takes place.     

WATERSHED PLANNING FOR ACID MINE DRAINAGE ABATEMENT1

Acid drainage from abandoned mines is a widespread problem in old mining regions. Agencies seeking to abate it face the prospect of dealing with hundreds of potential abatement projects, stretching decades into the future. A systematic regional analysis is necessary to establish locations, objectives, priorities, and phasing of such projects. The U.S. Bureau of Mines developed a novel procedure for abatement planning in the 420 square mile Blacklick Creek Watershed in Pennsylvania. The plan sought to direct abatement projects toward pollution sources where degradation was worst and adverse effects greatest. It established abatement priorities by comparing the “supply” of sources to be reclaimed (the degrees of old mines' water quality degradation) with the “demand” for abatement to be done (the natural and cultural values represented by the region's demography, land use and other non-mining characteristics). Matrices were used to define the relationships among mining and non-mining factors; maps were developed to show the geographic distribution of the conclusions. The locations, priorities, and phasing of abatement objectives shown on the maps should provide guidance for any abatement effort, no matter what type of technology is applied to achieve the objectives. Over the many years in which abatement projects are to be performed in the Watershed, the plan can be used to define, coordinate, and establish priorities for the projects in a manner that can result in maximum abatement benefits from the application of limited funds.