Kinetics of aerobic and anaerobic biomineralization of atrazine in surface and subsurface agricultural soils in Ohio

The purpose of this study was to assess atrazine mineralization in surface and subsurface samples retrieved from vertical cores of agricultural soils from two farm sites in Ohio. The Defiance site (NW-Ohio) was on soybean-corn rotation and Piketon (S-Ohio) was on continuous corn cultivation. Both sites had a history of atrazine application for at least a couple of decades. The clay fraction increased at the Defiance site and the organic matter and total N content decreased with depth at both sites. Mineralization of atrazine was assessed by measurement of ¹⁴CO₂ during incubation of soil samples with [U-ring-¹⁴C]-atrazine. Abiotic mineralization was negligible in all soil samples. Aerobic mineralization rate constants declined and the corresponding half-lives increased with depth at the Defiance site. Anaerobic mineralization (supplemented with nitrate) was mostly below the detection at the Defiance site. In Piketon samples, the kinetic parameters of aerobic and anaerobic biomineralization of atrazine displayed considerable scatter among replicate cores and duplicate biometers. In general, this study concludes that data especially for anaerobic biomineralization of atrazine can be more variable as compared to aerobic conditions and cannot be extrapolated from one agricultural site to another.     

How does it feel and how does it look? The role of employee motivation in organizational learning type

Employees' work outcomes vary as a function of their focus on exploring new possibilities versus exploiting current opportunities. But what determines how employees divide their attention between these contrasting work behaviors? Drawing on studies on work motivation and employees' impression management concerns, we examine how intrinsic work motivation and self‐enhancement motivation relate to the exploration–exploitation balance and how environmental dynamism moderates these relationships. Based on the analyses of a sample of 638 employees in 34 organizations in Finland, we find that intrinsic work motivation is positively associated with employees' focus on exploration relative to exploitation. By contrast, self‐enhancement motivation negatively associates with exploration relative to exploitation, but this relationship is nonlinear, such that as self‐enhancement motivation increases, its positive association with exploitation diminishes. The findings also show that the hypothesized nonlinear relationship between self‐enhancement motivation and exploration is particularly pronounced in stable business environments. Our findings contribute to organizational learning research and provide a new theoretical perspective on pursuing exploration and exploitation in organizations.     

Microbial populations identified by fluorescence in situ hybridization in a constructed wetland treating acid coal mine drainage

Microorganisms are an integral part of the biogeochemical processes in wetlands, yet microbial communities in sediments within constructed wetlands receiving acid mine drainage (AMD) are only poorly understood. The purpose of this study was to characterize the microbial diversity and abundance in a wetland receiving AMD using fluorescence in situ hybridization (FISH) analysis. Seasonal samples of oxic surface sediments, comprised of Fe(III) precipitates, were collected from two treatment cells of the constructed wetland system. The pH of the bulk samples ranged between pH 2.1 and 3.9. Viable counts of acidophilic Fe and S oxidizers and heterotrophs were determined with a most probable number (MPN) method. The MPN counts were only a fraction of the corresponding FISH counts. The sediment samples contained microorganisms in the Bacteria (including the subgroups of acidophilic Fe- and S-oxidizing bacteria and Acidiphilium spp.) and Eukarya domains. Archaea were present in the sediment surface samples at < 0.01% of the total microbial community. The most numerous bacterial species in this wetland system was Acidithiobacillus ferrooxidans, comprising up to 37% of the bacterial population. Acidithiobacillus thiooxidans was also abundant. Heterotrophs in the Acidiphilium genus totaled 20% of the bacterial population. Leptospirillum ferrooxidans was below the level of detection in the bacterial community. The results from the FISH technique from this field study are consistent with results from other experiments involving enumeration by most probable number, dot-blot hybridization, and denaturing gradient gel electrophoresis analyses and with the geochemistry of the site.     

Myanmar under reform: Emerging pressures on water,energy and food security

Myanmar's water‐related sectors are subject to intensive changes, as the country's abundant land and water resources provide substantial scope for development. Recent steps towards economic reform in Myanmar have led to a surge of foreign investment directed towards intensified natural resource extraction. Both the agricultural and the energy sector are increasingly affected by foreign investments that will impact the status of water, energy and food security in the country. With these on‐going developments, Myanmar's future is largely dependent on how its natural resources are managed and how the benefits from the resource extraction are shared. With various institutional changes and new actors welcomed to the sectors, existing livelihoods and ecosystems dependent on the land and water resources are to face increasing competition for the shared resources, while lacking secured access to them. There are increasing concerns that this sectoral development is occurring at the expense of environmental and social sustainability. As one way to tackle these challenges, the water‐energy‐food nexus approach could help in finding synergies and co‐benefits across sectors by addressing the imbalances along the nexus and externalities derived from the on‐going intensification.     

The South Karelia Air Pollution Study: Relationship of Outdoor and Indoor Concentrations of Malodorous Sulfur Compounds Released by Pulp Mills

We studied the indoor penetration of ambient air malodorous sulfur compounds released by pulp mills. The indoor and outdoor concentrations were simultaneously measured with automatic SO₂ analyzers. The filtering effect of three different materials connected to a gaseous filter unit was tested during six study periods. The tested materials were Sorbixofil® based on gypsum impregnated by KMnO₄ Purafil® based on Al₂O₃, both absorbing sulfur compounds by oxidation, and carbonized tissue. The periods lasted from 14 to 88 days. The results indicated that malodorous sulfur air pollutants penetrated indoors effectively, but after some delay because the dilution was slow. In a comparison of different filter materials, Purafil® was the most effective, producing low indoor concentrations. The study concludes that people living near pulp mills are exposed to substantial amounts of malodorous air pollutants, both indoors and outdoors. This exposure can be reduced by using gaseous sulfur sensitive filter materials connected to a controlled ventilation system.     

X-linked pyruvate dehydrogenase complex deficiency due to a novel PDHA1 variant associated with structural brain abnormalities in a fetus

We report a case of pyruvate dehydrogenase E1 alpha subunit deficiency associated with a novel hemizygous PDHA1 variant presenting prenatally as multiple structural brain abnormalities in a male fetus. A healthy Finnish couple was initially referred to the Fetomaternal Medical Center because of suspected fetal choroid plexus cyst at 11 + 2 weeks of pregnancy. At 20 + 0 weeks, multiple abnormalities were observed with ultrasound including narrow thorax, slightly enlarged heart, hypoplastic cerebellum, absent cerebellar vermis and ventriculomegaly. Autopsy and genetic analyses were performed after the termination of pregnancy. The findings of macroscopic examination included cleft palate, abnormally overlapping position of fingers and toes and dysmorphic facial features. Neuropathological examination confirmed the absence of corpus callosum, cerebellar hypoplasia and ventriculomegaly. Nodular neuronal heterotopia was also observed. Trio exome sequencing revealed a novel hemizygous de novo variant c.1144C>T p.(Gln382*) in the PDHA1 gene, classified as likely pathogenic. We suggest that inherited metabolic disorders should be kept in mind as differential diagnoses in fetuses with structural brain abnormalities.     

Concentrations of heavy metals in fly ash from a coal-fired power plant with respect to the new Finnish limit values

In Finland, the new limit values for heavy metals in fertilizers used in agriculture and in forestry came into force in March 2007, and for materials used as earth construction agents, in June 2006. From the utilization point of view, it was notable that the total heavy metal concentrations (Cd, Cu, Pb, Cr, Mo, Zn, As, Ni, Ba, and Hg) in fly ash from a coal-fired power plant were lower than those limit values. The concentrations of the easily soluble elements Ca, Mg, Na, P, and Zn in the fly ash were between 3.5 and 35 times higher than those found in the coarse mineral soils of Finland. Fly ash is a potential agent for soil remediation and for improving soil fertility. If inorganic materials and by-products are utilized in earthworks, the content of harmful compounds must be low and the harmful components must be tightly bound to the matrix. Therefore, a five-stage sequential extraction procedure was used to evaluate the extractability of different elements in fly ash into the following fractions: (1) the water-soluble fraction, (2) the exchangeable fraction (CH₃COOH), (3) the easily reduced fraction (NH₂OH-HCl), (4) the oxidizable fraction (H₂O₂ + CH₃COONH₄), and (5) the residual fraction (HF + HNO₃ + HCl).     

Endemic hantavirus infection impairs the winter survival of its rodent host

The influence of pathogens on host fitness is one of the key questions in infection ecology. Hantaviruses have coevolved with their hosts and are generally thought to have little or no effect on host survival or reproduction. We examined the effect of Puumala virus (PUUV) infection on the winter survival of bank voles (Myodes glareolus), the host of this virus. The data were collected by monitoring 22 islands over three consecutive winters (a total of 55 island populations) in an endemic area of central Finland. We show that PUUV infected bank voles had a significantly lower overwinter survival probability than antibody negative bank voles. Antibody negative female bank voles from low-density populations living on large islands had the highest survival. The results were similar at the population level as the spring population size and density were negatively correlated with PUUV prevalence in the autumn. Our results provide the first evidence for a significant effect of PUUV on host survival suggesting that hantaviruses, and endemic pathogens in general, deserve even more attention in studies of host population dynamics.     

Economics of harvesting age-structured fish populations

A generic age-structured model is developed to derive analytical results on optimal harvesting. Given two age classes, knife-edge selectivity, and no stock-dependent harvesting cost, the steady state is a unique saddle point. Adding harvesting cost does not alter the uniqueness, given that the utility is linear. Under specific conditions such as nonselective gear, optimal harvesting is proved to be a stationary cycle that represents pulse fishing. Optimal steady states are different if age-structured information is ignored and optimization is based on traditional biomass variables. This implies that the existence of optimal sustainable harvesting depends on age-structured information. Given a specific set of conditions such as low interest rate and knife-edge selectivity, optimal harvesting converges toward a unique saddle point independently of the number of age classes.