Groundwater connections between the boreal landscape and its headwater streams: the role of discrete riparian inflow points (DRIPs)

River networks connect the Swedish boreal landscape with the Baltic Sea. Groundwater provides a majority of the river water, and therefore it is important to understand the mechanisms of groundwater-stream interactions. The riparian zone, or near stream area, is an important terrestrial interface where groundwater becomes stream water. This thesis focused on riparian areas where subsurface flow paths converge, referred to as discrete riparian inflow points (DRIPs). DRIPs connect a large part of the landscape with a narrow section of the stream, and therefore represent landscape connectivity between hillslope and catchment scales. Results showed that DRIPs have near-surface groundwater levels and organic-rich groundwater chemistry. Combined with flow path convergence, this facilitates high mobilization rates of organic-rich groundwater to local points along stream reaches, which affects local stream ecosystems as well as downstream transport of carbon. Moreover, the response of DRIPs to changing hydrological conditions indicated that hydrological processes deviate from the rest of the riparian zone. Interactions between groundwater, peat-rich soil, vegetation and biota can be attributed to the contrasting characteristics of DRIPs compared to the rest of the riparian zone. This thesis demonstrated that DRIPs play an important role in both terrestrial and aquatic ecosystems in the Swedish boreal landscape. Therefore, DRIPs need to be explicitly considered in sustainable forest management

Development of a multiplex flow cytometric microsphere immunoassay for mycotoxins and evaluation of its application in feed

A multi-mycotoxin immunoassay—using the MultiAnalyte Profiling (xMAP) technology—is developed and evaluated. This technology combines a unique color-coded microsphere suspension array, with a dedicated flow cytometer. We aimed for the combined detection of aflatoxins, ochratoxin A, deoxynivalenol, fumonisins, zearalenone and T-2-toxin in an inhibition immunoassay format. Sets of six mycotoxin-protein conjugates and six specific monoclonal antibodies were selected, and we observed good sensitivities and no cross-interactions between the assays in buffer. However, detrimental effects of the feed extract on the sensitivities and in some cases on the slopes of the curves were observed and different sample materials showed different effects. Therefore, for quantitative analysis, this assay depends on calibration curves in blank matrix extracts or on the use of a suitable multi-mycotoxin cleanup. To test if the method was suitable for the qualitative detection at EU guidance levels, we fortified rapeseed meal, a feed ingredient, with the six mycotoxins, and all extracts showed inhibited responses in comparison with the non-fortified sample extract. Contaminated FAPAS reference feed samples assigned for a single mycotoxin showed strong inhibitions in the corresponding assays but also often in other assays of the multiplex. In most cases, the presence of these other mycotoxins was confirmed by instrumental analysis. The multiplex immunoassay can be easily extended with other mycotoxins of interest, but finding a suitable multi-mycotoxin cleanup will improve its applicability

Groundwater flow paths drive longitudinal patterns of stream dissolved organic carbon (DOC) concentrations in boreal landscapes

Preferential groundwater flow paths can influence dissolved organic carbon (DOC) concentration and export in the fluvial network because they facilitate the inflow of terrestrial DOC from large upslope contributing areas to discrete sections of the stream, referred to as discrete riparian inflow points (DRIPs). However, the mechanisms by which DRIPs influence longitudinal patterns of stream DOC concentrations are still poorly understood. In this study, we ask how DRIPs affect longitudinal patterns of stream DOC concentrations under different hydrologic conditions, as they can simultaneously act as major sources of terrestrial DOC and important locations for in-stream processes. To answer this question, we tested four model structures that account for different representations of hydrology (distributed inflows of DRIPs vs. diffuse groundwater inflow) and in-stream processes (no DOC uptake vs. in-stream DOC uptake downstream of DRIPs) to simulate stream DOC concentrations along a 1.5 km headwater reach for 14 sampling campaigns with flow conditions ranging from droughts to floods. Despite the magnitude and longitudinal patterns of stream DOC concentration varying across campaigns, at least one model structure was able to capture longitudinal trends during each campaign. Specifically, our results showed that during snowmelt periods or high-flow conditions (> 50 L s(-1)), accounting for distributed inputs of DRIPs improved simulations of stream DOC concentrations along the reach, because groundwater inputs from DRIPs diluted the DOC in transport. Moreover, accounting for in-stream DOC uptake immediately downstream of DRIPs improved simulations during five sampling campaigns that were performed during spring and summer, indicating that these locations served as a resource of DOC for aquatic biota. These results show that the role of DRIPs in modulating DOC concentration, cycling, and export varies over time and depends strongly on catchment hydrology. Therefore, accounting for DRIPs can improve stream biogeochemistry frameworks and help inform management of riparian areas under current and future climatic conditions

Combined serology and antibiotic residue detection in a Luminex assay

Serum of slaughter pigs is being used for routine testing of antibodies against pathogens and can be used for detection of antibiotic residues. Since the assay formats differ (direct detection of antibodies vs. inhibition assays for residues), these tests are performed in parallel, not in a multiplex set-up. For this study, a protocol for testing both antibodies and residues in one sample was investigated using the deticated multiplex xMAP platform for Luminex

Educating for self-interest or -transcendence? An empirical approach to investigating the role of moral competencies in opportunity recognition for sustainable development

Entrepreneurship education with a focus on sustainable development primarily teaches students to develop a profit‐driven mentality. As sustainable development is a value‐oriented and normative concept, the role of individual ethical norms and val‐ ues in entrepreneurial processes has been receiving increased attention. Therefore, this study addresses the role of moral competence in the process of idea generation for sustainable development. A mixed method design was developed in which would‐ be entrepreneurs were subjected to a questionnaire (n = 398) and to real‐life deci‐ sion‐making processes in a case assignment (n = 96). The results provide stepping stones for implementing (moral) competencies in entrepreneurship education as a possible avenue to move away from a sole focus on a profit‐driven mentalit

Exploring the relation between individual moral antecedents and entrepreneurial opportunity recognition for sustainable development

When dealing with complex value-driven problems such as sustainable development, individuals need to have values and norms that go beyond the appropriation of tangible business outcomes for themselves. This raises the question of the role played by individual moral antecedents in the entrepreneurial process of opportunity recognition for sustainable development. To answer this question, an exploratory empirical research design was used in which 96 would-be entrepreneurs were subjected to real-life decision-making processes in an online environment. The participants were guided through the process of opportunity recognition for sustainable development. Furthermore, they were subjected to several tests linked to individual moral antecedents. The mixed methods design used to analyze the results led to the conclusion that pro-environmental behavior values and moral competencies are important indicators of the ability to recognize opportunities for sustainable development. These results provide useful insights about relating moral antecedents to idea generation for sustainable development and can help researchers, higher education institutes, and sustainable entrepreneurs to further develop the concept of sustainable entrepreneurship and its underlying processes

Onderzoek naar de toepassing van seleniumsolen bij de ontwikkeling van een snelle test voor het aantonen van biologisch actieve verbindingen en milieucontaminanten op ppb-nivo

Tussen Holland biotechnology bv (Hbt) en het RIKILT is overeengekomen een gemeenschappelijk onderzoek op te zetten naar de mogelijke toepassing van seleniumsolen in eenvoudige screeningstests voor de analyse van stoffen op het (sub)ppb-nivo. Een seleniumsol, gekoppeld aan antilichamen of eiwitconjugaten, wordt gebruikt als specifiek kleurlabel. Bij de tot nu toe uitgevoerde experimenten is nortestosteron (NT) als teststof gebruikt, omdat hiervoor voldoende antiserum en NT-eiwitconjugaten , alsmede monstermateriaal en analysemethoden beschikbaar zijn om een test op te zetten en te valideren. In eerste instantie werd gekozen voor het ontwikkelen van een striptest met nitrocellulose als drager. Uit de verrichtte experimenten bleek dat met een geringe hoeveelheid NT-eiwitconjugaat op de nitrocellulosestrip (overeenkomend met 0,3 ng NT) al een kleuring werd verkregen met antilichamen gelabeld met sol . Ook is een geringe hoeveelheid antistof op de strip (4,7 pmol IgG, dat theoretisch maximaal 2,6 ng NT kan binden) voldoende om een kleuring te geven met NT-eiwitconjugaat dat aan de sol gekoppeld is. Het laagste nivo toegevoegd vrij NT, waarbij tot nu toe een (visueel) kleurverschil werd waargenomen bedroeg 60 ng/ml. Vermoedelijk heeft het antilichaam een grotere aviditeit voor het NT-eiwitconjugaat dan voor het vrije NT, hetgeen de test nadelig beïnvloed. Door een ander NT-eiwitconjugaat of zelfs een conjugaat van een ander steroid te kiezen, kan mogelijk een veel gevoeligere test worden verkregen. De tot nu verkregen resultaten zijn hoopgevend en bieden voldoende perspectief om het samenwerkingsprojekt voor langere termijn te continueren

Novel bead-based platform for direct detection of unlabelled nucleic acids through Single Nucleobase Labelling

Over the last decade, circulating microRNAs have received attention as diagnostic and prognostic biomarkers. In particular, microRNA122 has been demonstrated to be an early and more sensitive indicator of drug-induced liver injury than the widely used biomarkers such as alanine aminotransferase and aspartate aminotransferase. Recently, microRNA122 has been used in vitro to assess the cellular toxicity of new drugs and as a biomarker for the development of a rapid test for drug overdose/liver damage. In this proof-of-concept study, we report a PCR-free and label-free detection method that has a limit of detection (3 standard deviations) of 15 fmoles of microRNA122, by integrating a dynamic chemical approach for "Single Nucleobase Labelling" with a bead-based platform (Luminex®) thereby, in principle, demonstrating the exciting prospect of rapid and accurate profiling of any microRNAs related to diseases and toxicology