Abschätzung des Risikos einer Schwermetall-Akkumulation in Böden durch längerfristige Anwendung von Recycling- Phosphor-Düngemitteln

In order to assess the risk of the use of recycled phosphorus (P) fertilisers for organic farming, the potential accumulation of heavy metals in soil after a 200-year fertilizer application equivalent to 11 kg P ha-1 yr-1 was calculated in a mass balance approach. Both fertilizers currently allowed in organic farming and recycled P fertilizers were regarded. For heavy metals, four scenarios with two soil pH levels (pH 5 and pH 7) and two precipitation excess levels (F 0.1 and F 0.3 m yr-1) were calculated. Recycled P fertilizers like struvite, meat- and bone meal, ashes, sewage sludge and digestate, as well as phosphate rock and triple superphosphate had a higher P content and a lower heavy metal-to-P ratio than composts. Consequently, compost application was associated with the highest pollution risk. Only the Cd accumulation with TSP was higher than that with compost. Model calculations do not indicate a significant risk of heavy metal accumulation in soil compromising food quality or soil fertility after longterm application for the assessed recycled P fertilizers

Der Einfluss der Eltern im Berufswahlprozess von Jugendlichen mit Lernbeeinträchtigung

Die vorliegende Diplomarbeit befasst sich mit dem Berufswahlprozess von Jugendlichen mit Lernbeeinträchtigung und dem Einfluss der Eltern. Die Tatsache, dass die Eltern eine bedeutende Rolle im Berufswahlprozess ihrer Kinder einnehmen, steht in der bisherigen Literatur außer Frage. Wie dieser Einfluss im Detail aussieht, wurde lediglich kaum er-forscht. Diese Lücke versucht die vorliegende Arbeit zu schließen. Die theoretische Grundlage bilden das Gesamtmodell nach HERZOG et al. (2006) und dem darin enthalte-nen Phasen-Modell, sowie ein modifiziertes Einfluss-Modell, das sich an den Ausführun-gen von GEßNER (2003) orientiert, der zwischen impliziten und expliziten Einfluss unter-scheidet. Es wurden sowohl mit Jugendlichen als auch mit deren Eltern Interviews durch-geführt, um den Einfluss im Berufswahlprozess zu erforschen. Die Ergebnisse zeigten einen positiven Einfluss der Eltern besonders in den Bereichen „soziale Determinante“, „Einschätzung der Berufswahl“, „Vorbild“ und „Ökonomische Determinante“. Ein be-sonders negativer Einfluss konnte bezogen auf die „Wahl der vorherigen Schulform“ nachgewiesen werden.This thesis deals with the career development of young adolescents with learning disabili-ties and the influence of their parents. The fact that parents play a pivotal role in the career development process of their children is undoubted in contemporary literature. In contrast, research analysing this parental influence in detail is rather scarce. It is the aim of the following thesis to bridge this gap. The research is based on the theoretical concept by HERZOG et al. (2006) and particularly their stage-model, as well as on an influence-model derived from GEßNER (2003) which distinguishes between implicit and explicit parental influence. In this context, interviews were conducted with both youths and parents to assess their roles in career development. The results show a positive effect of parents espe-cially through the indicators "social determinant", "appraisal of career decision", "role model" and "economic determinant". A negative influence could be recognised concern-ing the "Choice of previous school type"

Akkumulation von Schadstoffen in europäischen Böden durch alternative Phosphordünger

Der Vorsorgewert wurde nur von Cr überschritten. Es zeigt sich, dass das Verhältnis von Schadstoff zu Phosphor eine wichtige Rolle spielt. Von Düngern mit einem geringen P-Gehalt, wie den Komposten, muss eine größere Menge ausgebracht werden, was in dieser Berechnung zu einer höheren Schadstoffanreicherung führte. Grüngutkompost hatte das höchste Akkumulationspotenzial für alle Schwermetalle, nur bei Cadmium wurde er von Triplesuperphosphat übertroffen. Vermutlich ist die atmosphärische Schermetallbelastung von Grünschnitt in Städten und entlang von Straßen besonders hoch und konzentriert sich im Kompost. Die Schadstoffgehalte der Dünger können, je nach Ausgangssubstraten, unterschiedlich sein. Als Phosphordünger eingesetzt, hatten Struvite, Fleisch- und Knochenmehl und Aschen das geringste Schadpotential. Die Schadstoffe, auch bei geringer Anreicherung im Boden, stellen eine Belastung des Wassers, des Staubs und der Kulturpflanzen darstellen dar

Freilandversuch zum Einfluss von Bewässerung, Rhizobien- und Mykorrhizainokulation auf Luzerne

In vorliegenden Versuch wurde der Einfluss der Inokulation von Medicago sativa L. cv. Sitel (Luzerne) mit Sinorhizobium meliloti und den arbuskulären Mykorrhizapilzen Glomus etunicatum, Glomus intraradices und Glomus claroideum auf das Wachstum, den Ertrag und die Stickstofffixierleistung untersucht. Die Auswirkungen der Mikroorganismen mit Bewässerung und mit natürlichem Niederschlag wurden in acht Varianten in einem einjährigen Feldversuch getestet. Der Versuch fand unter den Bedingungen des ökologischen Landbaus in der Ackerbauregion Marchfeld im Osten Österreichs statt. Zur Ermittlung der Stickstofffixierleistung der Luzerne wurde die 15N-Verdünnungsmethode verwendet, als Referenzpflanze diente Gras. Die Bewässerung hatte trotz eines niederschlagsreichen Versuchsjahres eine signifikant positive Wirkung auf die Biomasse und den N-Gehalt der Luzerne. Zwischen der Bewässerung und den Beimpfungen mit Mykorrhiza und Rhizobien zeigten sich deutliche Wechselwirkungen. Die Mykorrhizainokulation erhöhte mit Bewässerung die Gesamtbiomasse und den N-Gehalt, ohne Bewässerung führte die Mykorrhiza jedoch zu einer Verringerung der Gesamtbiomasse und des N-Gehalts der Luzerne. Die Beimpfung mit Sinorhizobium meliloti hatte ohne Bewässerung eine positive Auswirkung auf die Stängelbiomasse und den N-Gehalt der Luzerne. Die Wechselwirkung zwischen Rhizobien und Bewässerung war jedoch nicht so deutlich wie jene zwischen Mykorrhiza und Bewässerung. Wider Erwarten zeigte die Co-Inokulation mit Mykorrhiza und Rhizobien fast keinen Effekt auf die Luzerne. Die Folgewirkungen der Mykorrhizabeimpfung könnten an einer erhöhten Transpirationsrate der Luzerne liegen, die bei einigen Taxa und besonders bei G. etunicatum beobachtet wurde. Die verwendeten Rhizobien dürften besser an die Bedingungen des natürlichen Niederschlags angepasst gewesen sein.This study evaluates the effect of Sinorhizobium meliloti and arbuscular mycorrhizal fungi on growth, yield and biological nitrogen fixation of Medicago sativa L. cv. Sitel in a single growing season field trial under organic farming conditions. The impact of the used symbiotic microorganisms Sinorhizobium meliloti, Glomus etunicatum, Glomus intraradices and Glomus claroideum was tested in Eastern Austrian agricultural region of Marchfeld in rain feed conditions and with irrigation. The 15N-dilution method was operated for estimating the biological nitrogen fixation, furthermore grass was used as reference plant. Irrigation had a significantly positive effect on plant biomass and nitrogen contents of the plants, despite the relatively high precipitation during the experiment period. Also the interaction between the kind of water supply and the management of microorganisms was significant, but inoculations with mycorrhiza and rhizobacteria seemed to have contrasting effects on plant biomass and nitrogen contents. The interaction of mycorrhiza and S. meliloti did not influence the measured parameters significantly. Mycorrhiza inoculation under irrigated conditions affected the total amount of alfalfa biomass and nitrogen contents positively, whereas under rain fed conditions mycorrhiza inoculation reduced the total amount of alfalfa biomass and nitrogen contents. S. meliloti inoculation seemed to enhance biomass production and nitrogen contents of the roots on plots without irrigation. This difference can be explained by a higher transpiration rate by some mycorrhiza taxa, especially G. etunicatum, and a better adaptation of S. meliloti on water supply under rain fed conditions

LCA and Risk Assessment of Recycled Phosphorous Fertilisers

An efficient phosphorus (P) recycling from urban areas is becoming an increasing issue due to the scarcity of natural P deposits. In order to assess the environmental performance of different approaches of P recycling, a LCA assessment and risk assessment studies were carried out. Generally, we found the supply of recycled P-fertilisers (RPFs) to be competitive as compared to conventional sources in terms of LCA results analysed in this contribution: per kg P and with exclusion of infrastructure processes, the highest abiotic depletion potential is shown for conventional mineral fertilisers based on phosphate rocks due to the finite mineral P resources. For fossil primary energy demand, the recycled fertilisers (struvites and an ash-based fertiliser analysed) had highest impacts per kg P. Relatively high acidification and eutrophication potentials from the supply of P-fertilisers are related to composts, triple-superphosphate and struvites. For the global warming potential per kg P, compost presents the worst results again. However, if co-products of organic fertilisers are considered (i.e. N- and K-contents and the humus sequestration potential), most organic fertilisers are in advantage for a number of indicators – with the exception of conventional composting. The low emission compost and the stabilised sewage sludge present moderate to good overall results. The best relative results for all indicators were found for biogas digestate. To assess the risk of soil contamination related to the long-term application of RPFs, accumulation scenarios in soil were calculated with a mass balance approach for the potentially toxic elements (PTEs) Cd, Cr, Cu, Ni, Pb, and Zn and for the persistent organic pollutants (POPs) polychlorinated biphenyls (PCB), polycyclic aromatic hydrocarbons (PAH) and polychlorinated dibenzodioxins and dibenzofurans (PCDD/F) in composts, digestates and other RPFs derived from sewage sludge For all calculations, a fertiliser application over 200 years equivalent to 11 kg P ha-1 yr-1 was assumed. Dependent on PTE mobility in soil due to pH and precipitation excess F, an accumulation or depletion compared to the soil background values was found. Highest accumulation was found in scenario pH 7 F 0,1 m yr-1, lowest in scenario pH 5 F 0,3 m yr-1. Fertilisers like composts, with low P content compared to PTE load, had a higher accumulation potential than fertilisers like struvite, meat and bone meal, sewage sludge ash, sewage sludge and digestates, rock phosphate and triple super-phosphate. Only Cd accumulation with TSP was higher than that with compost. For POPs no accumulation risk in soil was found

Long-term soil accumulation of potentially toxic elements and selected organic pollutants through application of recycled phosphorus fertilizers for organic farming conditions

The pollutant input and the risk of contamination by long-term application of recycled P fertilizers (RPFs) in European agricultural soils were estimated by a mass balance approach. Calculations based on literature data were carried out for the potentially toxic elements (PTEs) Cd, Cr, Cu, Ni, Pb, Zn and for the persistent organic pollutants (POPs) PCBs, PAHs and polychlorinated dibenzo-dioxins and -furans. The PTE accumulation estimation during 200 years of fertilizer application, equivalent to 11 kg P ha-1 year-1, the mean P export via harvested products on European stockless organic farms, regarded soil background concentrations and proposed threshold concentrations. For PTEs, inputs were fertilizer application, atmospheric deposition and liming, output processes were leaching and crop harvest. The effect of varying site conditions was assessed by considering two precipitation excess (F) values and two soil pH values. For POPs, fertilizer application and the half-life time were considered. The PTE accumulation risk was low for most RPFs. For the analysed POPs no accumulation was found. The highest accumulation was found for all PTEs at pH 7 and F = 0.1 m year-1, the lowest at pH 5 and F = 0.3 m year-1. A high P concentration in fertilizers resulted in a low PTE flow per unit of P. composts had the highest PTE accumulation risk due to lowest P contents. Struvite, meat and bone meal, digestate of catering waste, ash and biosolids would be better suited as P fertilizers. The use of fertilizers should be regulated based on their pollutant-to-nutrient ratio

Neurostimulation Reveals Context-Dependent Arbitration Between Model-Based and Model-Free Reinforcement Learning

While it is established that humans use model-based (MB) and model-free (MF) reinforcement learning in a complementary fashion, much less is known about how the brain determines which of these systems should control behavior at any given moment. Here we provide causal evidence for a neural mechanism that acts as a context-dependent arbitrator between both systems. We applied excitatory and inhibitory transcranial direct current stimulation over a region of the left ventrolateral prefrontal cortex previously found to encode the reliability of both learning systems. The opposing neural interventions resulted in a bidirectional shift of control between MB and MF learning. Stimulation also affected the sensitivity of the arbitration mechanism itself, as it changed how often subjects switched between the dominant system over time. Both of these effects depended on varying task contexts that either favored MB or MF control, indicating that this arbitration mechanism is not context-invariant but flexibly incorporates information about current environmental demands

Begrenzte Phosphor-Ressourcen

Im CORE Organic Projekt „IMPROVE-P“ werden Strategien für ein nachhaltiges P-Management speziell für den Bio-Landbau entwickelt. Dazu wurden bei einem Workshop anlässlich der BIO AUSTRIA-Bauerntage 2016 Ergebnisse des Projekts zu P-Dünger-Pflanzenversuchen und Risikoabschätzung hinsichtlich Schwermetallen sowie Ökobilanzierung für P-Quellen von den Autoren dieses Beitrags präsentiert

Measuring visual perspective taking in the brain with avatars and arrows::Which question are we asking?

There is an ongoing debate about the involvement of Theory of Mind (ToM) processes in Visual Perspective Taking (VPT). In an fMRI study (Schurz et al., 2015), we borrowed the positive features from a novel VPT task – which is widely used in behavioral research – to study previously overlooked experimental factors in neuroimaging studies. However, as Catmur et al. (2016) rightly argue in a comment on our work, our data do not speak strongly to questions discussed in the original behavioral studies, in particular the issue of implicit mentalizing. We appreciate the clarification of these interpretational limitations of our study, but would like to point out the differences between questions emerging from behavioral and neuroimaging research on VPT. Different from what Catmur et al. (2016) discuss, our study was not intended as a test of implicit mentalizing. In fact, the terms “automatic” and “implicit mentalizing” were never mentioned in our manuscript. Our study addressed a methodological gap between ToM and VPT research, which we identified in two previous meta-analyses on the topics (Schurz et al., 2013, 2014). With this difference in mind we show that the critical points levelled by Catmur et al. (2016) cease to apply

Neurostimulation reveals context-dependent arbitration between model-based and model-free reinforcement learning

While it is established that humans use model-based (MB) and model-free (MF) reinforcement learning in a complementary fashion, much less is known about how the brain determines which of these systems should control behavior at any given moment. Here we provide causal evidence for a neural mechanism that acts as a context-dependent arbitrator between both systems. We applied excitatory and inhibitory transcranial direct current stimulation over a region of the left ventrolateral prefrontal cortex previously found to encode the reliability of both learning systems. The opposing neural interventions resulted in a bidirectional shift of control between MB and MF learning. Stimulation also affected the sensitivity of the arbitration mechanism itself, as it changed how often subjects switched between the dominant system over time. Both of these effects depended on varying task contexts that either favored MB or MF control, indicating that this arbitration mechanism is not context-invariant but flexibly incorporates information about current environmental demands