Groundwater flow, multicomponent transport and biogeochemistry: development and application of a coupled process model

A research tool for modeling the reactive flow and transport of groundwater contaminants in multiple dimensions is presented. Arbitrarily complex coupled kinetic–equilibrium heterogeneous reaction networks, automatic code generation, transfer-function based solutions, parameter estimation, high-resolution methods for advection, and robust solvers for the mixed kinetic–equilibrium chemistry are some of the features of reactive flow and transport (RAFT) that make it a versatile research tool in the modeling of a wide variety of laboratory and field experiments. The treatment of reactions is quite general so that RAFT can be used to model biological, adsorption/desorption, complexation, and mineral dissolution/precipitation reactions among others. The integrated framework involving automated code generation and parameter estimation allows for the development, characterization, and evaluation of mechanistic process models. The model is described and used to solve a problem in competitive adsorption that illustrates some of these features. The model is also used to study the development of an in situ Fe(II)-zone by encouraging the growth of an iron-reducing bacterium with lactate as the electron donor. Such redox barriers are effective in sequestering groundwater contaminants such as chromate and TCE.     

Multivariate curve resolution of multidimensional excitation-emission quenching matrices of a Laurentian soil fulvic acid

Fluorescence excitation–emission matrices (EEM) of aqueous solutions of Laurentian soil fulvic acid (LFA) at three concentrations (50, 75 and 100 mg/l) were obtained at two pH values (pH = 4.0 and 6.0) and as function of the Cu(II) ion concentration. The presence of Cu(II) ion provokes quenching of the intrinsic LFA fluorescence due to complex formation. Multivariate curve resolution (MCR-ALS) was used to successfully decompose single EEM into excitation and emission spectra for the detected components. Moreover, multidimensional (up to six dimensions) data matrices were generated by adding EEM collected as function of the LFA and Cu(II) concentrations and pH. MCR-ALS was able to resolve the excitation and emission spectra from these multidimensional data matrices given further information about the spectral variation profiles induced by the experimental factors. Conditional stability constants (log K_LFACu) were calculated from the quenching profiles observed as function of the Cu(II) concentration, as well as, their trends as function of pH and LFA concentration were obtained – average (and standard deviation) of log K_LFACu = 4.6 ± 0.2. This EEM/MCR-ALS methodology constitutes a new tool for the study of natural organic matter under varying experimental conditions that characterize natural environmental systems.     

Long-term trends in the Real real prices of primary commodities: Inflation bias and the Prebisch–Singer hypothesis

In his recent article on measuring the long-term trends in the real prices of primary commodities, Cuddington (2010) extends in several important respects our earlier efforts (Svedberg and Tilton, 2006) to correct real commodity price trends for biases in the Consumer Price Index and other deflators. First, he argues for a log-linear relationship between prices and time. Second, he proposes a simple and quick method for obtaining corrected price trends from the published but uncorrected estimates. Finally, he illustrates, for the case of copper and presumably for many other commodities as well, the difficulties of obtaining real price trends significantly different from zero when the log values of the price data contain a unit root, requiring the use of difference stationary models.We welcome these insights, which should improve and make easier efforts to estimate correctly real commodity price trends over the long run. We would stress, however, that it is still important to correct for the biases in inflation indices, notwithstanding the failure of difference stationary models to obtain long-run real price trends (both corrected and uncorrected) significantly different from zero.     

How does spouse career support relate to employee turnover? Work interfering with family and job satisfaction as mediators

Employee turnover is a major concern because of its cost to organizations. Although theory supports the influence of nonwork factors on turnover, our understanding of the degree to which nonwork factors relate to actual turnover behavior is not well developed. Using a sample of 5505 U.S. Army officers, we assessed the extent to which spouse career support related to reduced turnover four years later through work interfering with family (WIF) and job satisfaction as mechanisms. Results revealed that spouse career support decreased the odds of turnover, and WIF and job satisfaction sequentially mediated this relationship, with lower WIF and higher job satisfaction reducing the odds of turnover. Practical implications of using family support systems as retention interventions are discussed. Copyright © 2013 John Wiley & Sons, Ltd.     

Differential treatment within sports teams,leader–member (coach–player) exchange quality,team atmosphere,and team performance

Using the leader–member exchange (LMX) theory as a theoretical framework, the present study focused on the occurrence of differential treatment by leaders on social and task‐related issues within teams. It was investigated whether team members' perceptions of the frequency and degree of social and task‐related differential treatment by the leader were associated with their evaluation of team atmosphere and team performance, in addition to the effects of the quality of their own working relationship with the leader (LMX quality). The context of this study consisted of interdependent sports teams. The participants were 605 players belonging to 69 amateur sports teams playing various team sports such as soccer, hockey, and basketball. Social differential treatment was negatively associated with team atmosphere and unrelated to team performance. In addition, it was found that the two forms of task‐related differential treatment included in this study were unrelated to team atmosphere and were differently associated with team performance. The results are discussed with reference to the existing leadership literature. Copyright © 2010 John Wiley & Sons, Ltd.     

Selecting agri-environmental indicators to facilitate monitoring and assessment of EU agri-environmental measures effectiveness

Since its introduction in the early 1960s, the EU Common Agricultural Policy (CAP) has demonstrated a capacity to adapt and change in the face of new challenges. The reformed CAP, under AGENDA 2000, encourages more environmentally friendly farming practices. In the context of their rural development plans, Member States are required to link policies on agriculture with protection of the environment and to ensure that farmers meet environmental standards. Additionally, Member States should maintain and restore the quality of both their aquatic and adjacent terrestrial ecosystems according to the Directive 2000/60/EU, 'Establishing a framework for Community Action in the field of Water Policy'. Within this framework, agri-environmental indicators play an important role in planning and implementing CAP guidelines. However, selection and use of the proper indicators remains unresolved, considering that ecosystem processes are complex and interactions in most cases not obvious. This paper proposes a methodology for assessing the environmental state and impacts of current land use and management when implementing agri-environmental measures of CAP. The proposed methodology includes a modified Driving forces-Pressures-Impacts-Responses (DPSIR) framework, identification of Zones of Specific Functional Interest (ZSFI), and criteria for selecting agri-environmental indicators, which assess the functional performance of each zone and meet existing legislation. The Mygdonia Watershed (Greece) is an example where through use of both the appropriate Minimum Data Set of agri-environmental indicators at the identified zones and the proposed modified DPSIR, the functioning performance of each ZSFI can be assessed to evaluate the applied agri-environmental measures.     

Cleaner production in the ammonia-soda industry: an ecological and economic study

Five methods to reduce the negative influence of soda ash factories on the natural environment are presented: 1. obtaining calcium-magnesium phosphates by treating the suspension from raw brine purification with orthophosphoric acid (H(3)PO(4)), 2. production of precipitated chalk from soda processing waste, 3. production of gypsum and semi-brine, 4. desulphurisation of fume gases from the factory power plant, 5. utilization of distiller waste. The tests, accomplished on a laboratory scale, showed the high efficiency of these methods. Economic analysis has proved that only four out of the five presented processes can have a positive financial effect on soda ash factories, as well as being well justified economically. The value of two of the innovations presented is confirmed by their implementation in factories.     

Adaptive Comanagement for Building Resilience in Social–Ecological Systems

Ecosystems are complex adaptive systems that require flexible governance with the ability to respond to environmental feedback. We present, through examples from Sweden and Canada, the development of adaptive comanagement systems, showing how local groups self-organize, learn, and actively adapt to and shape change with social networks that connect institutions and organizations across levels and scales and that facilitate information flows. The development took place through a sequence of responses to environmental events that widened the scope of local management from a particular issue or resource to a broad set of issues related to ecosystem processes across scales and from individual actors, to group of actors to multiple-actor processes. The results suggest that the institutional and organizational landscapes should be approached as carefully as the ecological in order to clarify features that contribute to the resilience of social–ecological systems. These include the following: vision, leadership, and trust; enabling legislation that creates social space for ecosystem management; funds for responding to environmental change and for remedial action; capacity for monitoring and responding to environmental feedback; information flow through social networks; the combination of various sources of information and knowledge; and sense-making and arenas of collaborative learning for ecosystem management. We propose that the self-organizing process of adaptive comanagement development, facilitated by rules and incentives of higher levels, has the potential to expand desirable stability domains of a region and make social–ecological systems more robust to change.Published online     

Adaptation of RUSLE in the Eastern Part of the Mediterranean Region

Empirically based models are used worldwide to estimate soil erosion. The Revised Universal Soil Loss Equation (RUSLE) is one such model that has been intensively tested and validated under conditions in the United States. RUSLE estimates average soil loss as a function of five main factors: rainfall erosivity (R), soil erodibility (K), crop management (C), support practice (P), and topographic (LS) factors. This study investigated the application of RUSLE to Mediterranean conditions. The validation and calibration of RUSLE in the study area utilized field plots soil erosion measurements. The results found the RUSLE soil loss estimation to be three times the actual soil loss (7.8 and 2.6 Mg/ha, for RUSLE and actual measured soil loss, respectively). The difference between the RUSLE factors and the measured factors were responsible for the differences between the soil loss estimation by RUSLE and the measured soil loss. Specifically, the RUSLE K-factor showed three times the magnitude of the measured K-factor, the RUSLE C-factor underestimated the measured C-factor, and the RUSLE P-factor overestimated the measured P-factor by three times. Adjusting the RUSLE factors according to the measured ones increased the models predictability, whereas the adjusted-RUSLE soil loss estimation underestimated the measured soil loss by 14%. The adjustment of RUSLE, according to the prevailing conditions of the study area, increased the model efficiency three times (0.26 and 0.86 before and after adjustment of the mode,l respectively). For more accurate and reliable validation of the RUSLE under the Mediterranean conditions, it is advisable to conduct long-term soil loss experimentation and measurements.     

Tree Ontogeny and Its Reflection in the Structure and Dynamics of Plant and Soil Covers

Based on the results of our own long-term experiments and the analysis of published data, the process of individual development (ontogeny) of trees and the parameters of ontogenetic stages are described. Changes in the environment-forming (edificatory) role of a tree in the course of ontogeny and upon its completion are characterized. The performance of this role leads to the formation of the following components of biogeocenosis heterogeneity: phytogenic fields of trees, gaps in the tree canopy, and windfall–soil complexes. The data concerning the interrelation of structural transformations of the plant and soil covers in the course of forest vegetation and soil formation on the primary substrate are reviewed.