Pathogen-induced hatching and population-specific life-history response to waterborne cues in brown trout (Salmo trutta)

Hatching is an important niche shift, and embryos in a wide range of taxa can either accelerate or delay this life-history switch in order to avoid stage-specific risks. Such behavior can occur in response to stress itself and to chemical cues that allow anticipation of stress. We studied the genetic organization of this phenotypic plasticity and tested whether there are differences among populations and across environments in order to learn more about the evolutionary potential of stress-induced hatching. As a study species, we chose the brown trout (Salmo trutta; Salmonidae). Gametes were collected from five natural populations (within one river network) and used for full-factorial in vitro fertilizations. The resulting embryos were either directly infected with Pseudomonas fluorescens or were exposed to waterborne cues from P. fluorescens-infected conspecifics. We found that direct inoculation with P. fluorescens increased embryonic mortality and induced hatching in all host populations. Exposure to waterborne cues revealed population-specific responses. We found significant additive genetic variation for hatching time, and genetic variation in trait plasticity. In conclusion, hatching is induced in response to infection and can be affected by waterborne cues of infection, but populations and families differ in their reaction to the latter.     

The effect of air control systems on the indoor distributions of viable particles

We have investigated the filtering effects of three types of air control systems of enclosed structures on viable particles in the ambient air. Aspergillus fumigatus and other thermophilic organisms were used as monitors for viable particles. The indoor concentrations of viable particles were found to be affected by building design and the use of conventional mechanical air systems. Viable particles of approximately 4.0 μm and greater in aerodynamic diameter were filtered from the air while respirable size particles less than 4.0 μm were not filtered as well. There was evidence of growth of viable particles within the mechanical air systems. Conventional air control systems may not be adequate for the control of viable particle contamination of the indoor environment without modifications and proper maintenance.     

Pulmonary function evaluation of cats after one year of exposure to diesel exhaust

Adult male, inbred, disease-free cats of uniform age and size were exposed eight hours per day, seven days per week to a 1 : 18 dilution of diesel exhaust emissions. After one year of exposure, the animals were removed from the chambers for measurement of lung volumes, forced expiratory flow rates, dynamic compliance and resistance, diffusing capacity, and nitrogen washout. No important changes in pulmonary function were detected with the exception of a decrease in closing volume (P < 0.05). The inability to detect decrements in pulmonary function may have been due to insufficient cocentration of exhaust, insufficient exposure length, or to the use of a species resistant to diesel exhaust. To test these possibilities, the cats are being exposed for an additional year, and another species, hamsters, are being exposed for future testing at exhaust dilutions of 1 : 18 and 1 : 9.     

Urgently reveal longly hidden toxicant in a familiar fabrication process of biomass-derived environment carbon material

Biomass-derived N-doped carbon (BNC) is an important environmental material and widely used in the fields of water purification and soil remediation. However, the toxicant in the commonly used synthesis process of BNC materials have been largely ignored. Herein, we firstly report the presence of a highly toxic by-product (KCN) in the activation process of BNC materials consequential of the carbothermal reduction reaction. Because this carbothermal reduction reaction also regulates the N-doping and pore development of BNC materials, the KCN content directly relates with the properties of BNC material properties. Accordingly, a high KCN content (∽ 611 mg) can occur in the production process of per g BNC material with high specific surface area (∽ 3600 m²/g). Because the application performance of BNC material is determined by the surface area and available N doping, therefore, production of a BNC material with high performance entails high risk. Undoubtedly, this study proves a completely new risk recognition on a familiar synthesis process of biomass-based material. And, strict protective device should be taken in fabrication process of biomass-derived carbon material.     

SWATmodel: A Multi‐Operating System,Multi‐Platform SWAT Model Package in R

The Soil and Water Assessment Tool (SWAT) model (Arnold et al., 1998) is a popular watershed management tool. Currently, the SWAT model, actively supported by the U.S. Department of Agriculture and Texas A&M, operates only on Microsoft^® Windows, which hinders modelers that use other operating systems (OS). This technical note introduces the Comprehensive R Archive Network (CRAN) distributed “SWATmodel” package which allows SWAT 2005 and 2012 to be widely distributed and run as a linear model‐like function on multiple OS and processor platforms. This allows researchers anywhere in the world using virtually any OS to run SWAT. In addition to simplifying the use of SWAT across computational platforms, the SWATmodel package allows SWAT modelers to utilize the analytical capabilities, statistical libraries, modeling tools, and programming flexibility inherent to R. The software allows watershed modelers to develop a simple hydrological watershed model conceptualization of the SWAT model and to obtain a first approximation of the minimum expected results a more complicated model should deliver. As a proof of concept, we test the SWAT model by initializing and calibrating 314 U.S. Geological Survey stream gages in the Chesapeake Bay watershed and present the results.     

EVALUATING THE INFLUENCE OF SOURCE BASINS ON DOWNSTREAM WATER QUALITY IN THE MISSISSIPPI RIVER1

ABSTRACT: Chemical variability in the Mississippi River during water years 1989 to 1998 was evaluated using stream discharge and water‐quality data in conjunction with the DAFLOW/BLTM hydraulic model. Model simulations were used to identify subbasin contributions of water and chemical constituents to the Mississippi River upstream from its confluence with the Ohio and the Mississippi River and at the Atchafalaya Diversion in Louisiana. Concentrations of dissolved solids, sodium, and sulfate at the Thebes site showed a general decreasing trend, and concentrations of silica and nitrate showed a general increasing trend as the percentage of discharge from the Mississippi River upstream from Grafton increased. Concentrations of most chemical constituents in the Mississippi River at the Atchafalaya Diversion exhibited a decreasing trend as the percentage of water from the Ohio River increased. Regression models were used to evaluate the importance of the source of water to the water chemistry in the Mississippi River at Thebes and the Atchafalaya Diversion. The addition of terms in regression equations to account for the percent of water from sub‐basins improved coefficients of determination for predicting chemical concentrations by as much as nine percent at the Thebes site and by as much as 48 percent at the Atchafalaya Diversion site. The addition of source‐water terms to regression equations increased the estimated annual loads of nitrate and silica delivered from the Mississippi River Basin to the Gulf of Mexico by as much as 14 and 13 percent, respectively.     

An economic model of soil conservation/depletion

Land is defined in terms of its qualitative characteristics in order to focus upon conservation/depletion decisions made with respect to the soil. The qualitative definition of land involves a capital component (total nitrogen content) and a Ricardian component (total precipitation). The economic model developed utilizes neoclassical capital theory to describe individual behavior in a conservation/depletion context. An important concept to the system is that of user cost; it is this concept which provides an economic rationale for fallow, a decision which requires the entrepreneur to forego static income as well as depleting the soil.     

The USSR, China, India and the world metals industry to 2010

Remarkable changes are occurring within the economies of the USSR, China and India that are influencing mineral industry activities. These three countries account for a major share of world minerals production and consumption. Their domestic reforms may ultimately have a serious impact on the global mining industry. This paper examines the present status of the Soviet, Chinese and Indian mineral industries, and forecasts conditions to 2010. Long-term characteristics analysed include industrial production, intensity of use, consumption, mine and plant expansion and trade policy. Six metals are highlighted in the study – aluminium, copper, lead, nickel, steel and zinc.     

Environmental factors influencing attenuation of methane and hydrochlorofluorocarbons in landfill cover soils

The influence of different environmental factors on methane oxidation and degradation of hydrochlorofluorocarbons (HCFCs) was investigated in microcosms containing soil sampled at Skellingsted Landfill, Denmark. The soil showed a high capacity for methane oxidation resulting in a maximum oxidation rate of 104 microg CH4 g(-1) h(-1) and a low affinity of methane with a half-saturation constant of 2.0% v/v. The hydrochlorofluorocarbons HCFC-21 (dichlorofluoromethane) and HCFC-22 (chlorodifluoromethane) were rapidly oxidized and the oxidation occurred in parallel with the oxidation of methane. The maximal HCFC oxidation rates were 0.95 and 0.68 microg g(-1) h(-1) for HCFC-21 and HCFC-22, respectively. Increasing concentrations of HCFCs resulted in decreased methane oxidation rates. However, compared with typical concentrations in landfill gas, relatively high HCFC concentrations were needed to obtain a significant inhibition of methane oxidation. In general, the environmental factors studied influenced the degradation of HCFCs in almost the same way as they influenced methane oxidation. Temperature had a strong influence on the methanotrophic activity giving high Q10 values of 3.4 to 4.1 over the temperature range of 2 to 25 degrees C. Temperature optimum was around 30 degrees C; however, oxidation occurred at temperatures as low as 2 degrees C. A moisture content of 25% w/w yielded the maximum oxidation rate as it allowed good gas transport together with sufficient microbial activity. The optimum pH was around neutrality (pH = 6.5-7.5) showing that the methanotrophs were optimally adapted to the in situ pH, which was 6.9. Copper showed no inhibitory effect when added in relatively high concentrations (up to 60 mg kg(-1)), most likely due to sorption of copper ions to soil particles. At higher copper concentrations the oxidation rates decreased. The oxidation rates for methane, HCFC-21, and HCFC-22 were unaltered in ammonium-amended soil up to 14 mg kg(-1). Higher ammonium concentrations inhibited the oxidation process. The most important parameters controlling oxidation in landfill cover soil were found to be temperature, soil moisture, and methane and oxygen supply.