Advances in understanding natural groundwater quality controls in coastal aquifers

Groundwater quality in coastal aquifers is largely influenced by the interaction between the sea and the bordering aquifer systems. This interaction can result in freshening of saline aquifers or salinization of fresh water bodies. In complex cases even both situations can be found in the same aquifer system. While the main mechanism for salinization or freshening is hydrodynamically driven (groundwater flow), also physical and chemical processes within the aquifer will alter groundwater composition. Cation exchange is in many cases an important process to consider; it results in a hydrochemical spectrum of groundwater types reflecting both the hydrodynamical and hydrochemical characteristics of the aquifer.In order to understand the natural groundwater quality and the controlling processes in a coastal aquifer, it is crucial to known both the hydrodynamical and hydrochemical behaviour and the way these are linked together, because usually only the interaction between them can explain the observed quality istributions.Where mixing of fresh and salt water occurs, density-driven flow may become important and change quality distribution, while the groundwater composition itself influences hydrodynamics. An integrated approach of both aspects is indispensable.Modelling is an important tool in understanding how aquifer systems work. Until recently, hydrodynamical and hydrochemical aspects were tackled separately, with different models. Hydrodynamical aspects have been studied with flow models (such as MODFLOW) or a combination of a flow and a solute transport model (such as MT3D) for simulating salt transport, coupled together for incorporating density-driven flow (such as in SEAWAT). On the other hand, hydrochemical aspects have been investigated with hydrogeochemical models based on speciation and a reaction scheme. In hydrogeochemical models, groundwater flow was either not taken into account, or, at best, it was considered in a very simplified approach (along a path-line). Recently, codes have been developed combining three-dimensional flow models fully with the flexibility of an extensible hydrochemical model based on thermodynamic databases, such as PHAST, which combines the well-known PHREEQC model with the HST3D model for flow and transport. Simulations with the PHAST model have shown that it is capable of simulating the whole hydrochemical spectrum of groundwater types in coastal aquifers under freshening and salinizing conditions incorporating cation exchange processes and mineral equilibria such as calcite dissolution. The capabilities of this new generation of models will also allow for including redox components (iron content of the water) or processes such as surface complexation (e.g. sorption onto hydroxides). The future for such models looks bright, because for the first time they will provide the complete groundwater composition as their output.However, models need to be based on good and sufficient field data! Without them the reliability of the models is unknown and their value for predictive purposes is hypothetical. Therefore the advances in modelling should go together with new techniques of sampling, measuring and monitoring and with improved analytical methods. Advances have been made also in these fields. Yet, the most important advance in understanding natural groundwater quality is not related to a specific technical innovation but rests in the minds of hydrogeologists. Indeed, only a profound insight in the combined hydrodynamical and hydrochemical aspects by a refined system analysis can provide the key to really understand what controls groundwater quality, also in coastal aquifers

Ranking of water-table depths for purposes of ecosystem management in the coastal dunes of Belgium

Integrated monitoring was conducted to evaluate the result of nature development actions to increase the biodiversity. During the first year, the natural fluctuation of the piezometric level has been determined based on existing data and newly gathered data. From these data, the groundwater table classes following a classification, developed in The Netherlands, have been deduced. However, the result does not correspond with the observed vegetation. To predict the natural habitats and ecosystems in the coastal dunes of Belgium, a new classification adapted to natural conditions in the area is required. Advantages of existing approaches are integrated in the classification, combined with new elements, to represent the relationship between groundwater regimes and ecosystems. This new classification, consisting of 4 codes, provides information about the mean high water table depth, the mean low water table depth, mean spring water table depth and whether inundation can take place or not. It also gives an indication of the variability of the seasonal fluctuations of the water table and the importance of the fluctuation of the water table between years. With this new classification, a fine breakdown by ecotypes is possible. The new classification has been applied to the existing data in the study area

Searching for the effect of multiple uncontrolled interventions in BRMS

We search for the effects of 8 different (uncontrolled) interventions (1intervention per school) on the sub-concepts of learner’s (4th to 8th grade)motivation, self-regulation, and ICT competency data over the past threeyears. Data marking for intervention (yes/no), ICT competence of teachersand the presence of specially trained teachers are added to the formulas.Assessment of ICT competency in 3rd grade can be used as prior. Smoothsillustrate if the (motivation or self-regulation) concepts grow over timegrouped by intervention, school or grade. Grades are nested within schoolsand data is grouped by student. Are we missing anything

Using a gamified monitoring app to change adolescents' snack intake : the development of the REWARD app and evaluation design

Background: As the snacking pattern of European adolescents is of great concern, effective interventions are necessary. Till now health promotion efforts in children and adolescents have had only limited success in changing adolescents' eating patterns and anthropometrics. Therefore, the present study proposes an innovative approach to influence dietary behaviors in youth based on new insights on effective behavior change strategies and attractive intervention channels to engage adolescents. This article describes the rationale, the development, and evaluation design of the 'Snack Track School' app. The aim of the app is to improve the snacking patterns of Flemish 14- to 16-year olds. Methods: The development of the app was informed by the systematic, stepwise, iterative, and collaborative principles of the Intervention Mapping protocol. A four week mHealth intervention was developed based on the dual-system model with behavioral change strategies targeting both the reflective (i.e., active learning, advance organizers, mere exposure, goal-setting, monitoring, and feedback) and automatic processes (i.e., rewards and positive reinforcement). This intervention will be evaluated via a controlled pre-post design in Flemish schools among 1400 adolescents. Discussion: When this intervention including strategies focused on both the reflective and automatic pathway proves to be effective, it will offer a new scientifically-based vision, guidelines and practical tools for public health and health promotion (i.e., incorporation of learning theories in intervention programs)

Follow-up of bone lesions in an experimental multiple myeloma mouse model: description of an in vivo technique using radiography dedicated for mammography.

The evolution of bone lesions in transplantable C57BL/KaLwRjj 5T mouse myeloma (MM) has been followed in vivo. Mice were anaesthetised and a radiograph of the pelvis and hind legs was performed by a radiograph dedicated for mammography. This is the first description of an in vivo technique under experimental conditions whereby the development of bone lesions owing to the MM growth was demonstrated

Measuring the Development of ICT Skills for Personalized Learning:Developing an Instrument for Dutch Primary Education

Our study investigates the development and validation of a questionnaire for competencies learners need to learn in a personalized way using ICT. 9 Dutch schools for primary education collaborate to make personalized learning with ICT evidence-informed. At these 9 iXperium schools, multidisciplinary design teams (consisting of primary school teachers and principals, teachers and students of the teacher-training program of a Dutch university of applied science, researchers from a Dutch university, and external ICT experts) design and research integrated interventions for PL with ICT. We defined personalized learning conditions before filtering the twenty-four learning objectives needed to measure development in personalized learning using ICT. The final questionnaire consists of thirty-three questions to cover the learning objectives. The validity and reliability of our questionary are analyzed in six steps. Cognitive validity (1) and a response model (2) are reported based on literature and a pilot with three iterative rounds of interviews (n=19). Internal constancy (3), confirmatory factor analysis (4), coefficient H (5) are reported after the first run of the questionnaire (n=800), and a test-retest alpha is reported after the second run of the questionnaire (n=800)