Comparison of some chemical and non-chemical treatments to disinfect a recirculating nutrient solution

Closed hydroponic growing systems have a better water use efficiency (WUE) and a lower use of fertilizers, but a larger risk of spreading soil-borne pathogens all over the crop compared to open systems. In climates or regions where availability of water is limited closed systems should be preferred above open systems but the risk of spreading soil-borne pathogens should be minimized. Disinfection of the nutrient solution is a valuable method, but it often demands high investments. A desk study was made to compare the performance of some chemical and non-chemical treatments. For larger companies (>2 ha) heat treatment and UV radiation are still the best options. For smaller companies

Disease management in soilless culture systems

EU legislation, laid down in the Water Framework Directive, demands to minimize emissions of nitrogen, phosphate and crop protection products to achieve an excellent chemical and ecological quality in 2015. The aim is to force growers to a better water and disease management. Supply water of excellent chemical quality will have to be recirculated as long as possible, for which adequate disinfection equipment have to be used. Several sources of water are used as supply water. Rainwater is chemically best, followed by reverse osmosis water. However, the latter is rather expensive. Tap water and surface water often have a too high salinity, while well water may vary dramatically from place to place. Rainwater and surface water are potential risk factors for importing soil-borne pathogens. Disinfection of the recirculating nutrient solution can be done adequately by heat treatment and UV radiation. Membrane filtration performs well, but is mostly too costly. Chemical treatments as sodium hypochlorite, chlorine dioxide and copper silver ionization may partly solve the pathogen problem, but introduce a potential accumulation of other elements in closed systems. Hydrogen peroxide, chlorine dioxide and sodium hypochlorite perform better to clean pipe work instead of soil-borne pathogens

Endogenous TRPV1 stimulation leads to the activation of the inositol phospholipid pathway necessary for sustained Ca2+ oscillations

Sensory neuron subpopulations as well as breast and prostate cancer cells express functional transient receptor potential vanilloid type 1 (TRPV1) ion channels; however little is known how TRPV1 activation leads to biological responses. Agonist-induced activation of TRPV1 resulted in specific spatiotemporal patterns of cytoplasmic Ca²⁺ signals in breast and prostate cancer-derived cells. Capsaicin (CAPS; 50 μM) evoked intracellular Ca²⁺ oscillations and/or intercellular Ca²⁺ waves in all cell lines. As evidenced in prostate cancer Du 145 cells, oscillations were largely dependent on the expression of functional TRPV1 channels in the plasma membrane, phospholipase C activation and on the presence of extracellular Ca²⁺ ions. Concomitant oscillations of the mitochondrial matrix Ca²⁺ concentration resulted in mitochondria energization evidenced by increased ATP production. CAPS-induced Ca²⁺ oscillations also occurred in a subset of sensory neurons, yet already at lower CAPS concentrations (1 μM). Stimulation of ectopically expressed TRPV1 channels in CAPS-insensitive NIH- 3T3 cells didn't provoke CAPS-triggered Ca²⁺ oscillations; rather it resulted in low- magnitude, long-lasting elevations of the cytosolic Ca²⁺ concentration. This indicates that sole TRPV1 activation is not sufficient to generate Ca²⁺ oscillations. Instead the initial TRPV1-mediated signal leads to the activation of the inositol phospholipid pathway. This in turn suffices to generate a biologically relevant frequency-modulated Ca²⁺ signal

Around the table: Are multiple-touch surfaces better than single-touch for children's collaborative interactions?

This paper presents a classroom study that investigated the potential of using touch tabletop technology to support children's collaborative learning interactions. Children aged 7-10 worked in groups of three on a collaborative planning task in which they designed a seating plan for their classroom. In the single-touch condition, the tabletop surface allowed only one child to interact with the digital content at a time. In the multiple-touch condition, the children could interact with the digital content simultaneously. Results showed that touch condition did not affect the frequency or equity of interactions, but did influence the nature of children's discussion. In the multiple-touch condition, children talked more about the task; in the single-touch condition, they talked more about turn taking. We also report age and gender differences

Analysis and new constructions of generalized barycentric coordinates in 2D

Different coordinate systems allow to uniquely determine the position of a geometric element in space. In this dissertation, we consider a coordinate system that lets us determine the position of a two-dimensional point in the plane with respect to an arbitrary simple polygon. Coordinates of this system are called generalized barycentric coordinates in 2D and are widely used in computer graphics and computational mechanics. There exist many coordinate functions that satisfy all the basic properties of barycentric coordinates, but they differ by a number of other properties. We start by providing an extensive comparison of all existing coordinate functions and pointing out which important properties of generalized barycentric coordinates are not satisfied by these functions. This comparison shows that not all of existing coordinates have fully investigated properties, and we complete such a theoretical analysis for a particular one-parameter family of generalized barycentric coordinates for strictly convex polygons. We also perform numerical analysis of this family and show how to avoid computational instabilities near the polygon’s boundary when computing these coordinates in practice. We conclude this analysis by implementing some members of this family in the Computational Geometry Algorithm Library. In the second half of this dissertation, we present a few novel constructions of non-negative and smooth generalized barycentric coordinates defined over any simple polygon. In this context, we show that new coordinates with improved properties can be obtained by taking convex combinations of already existing coordinate functions and we give two examples of how to use such convex combinations for polygons without and with interior points. These new constructions have many attractive properties and perform better than other coordinates in interpolation and image deformation applications

The resurrected Jesus and the marginalized people: from a Buraku liberation perspective

Discrimination is one of the most challenging issues that we are faced with in the world today. It impairs human dignity and dehumanizes individuals and particular group of people, violating the order of God’s creation. It has and continues to be a critical issue and a serious challenge for Christian churches today. This thesis aims to link the theme of the liberation for the Burakumin who are the discriminated and marginalized people in Japanese society over a period of years, with the liberating message of the Gospel, and the ecumenical commitment towards the issue of discrimination. The Burakumin are not really known in the world outside Japan. An attempt is made to highlight their discriminatory situation and their struggle for liberation. An attempt has also been made to study the Buraku liberation theology as one of the contextualized liberation theology and highlights its relevance and contribution towards the struggle against the discrimination in Japanese society and also the world at large. Then, as an example of the ecumenical biblical interpretation for the liberation of the marginalized people, it attempts has been made to interpret and re-read the biblical text about the story of the resurrection in John 20:11-18 from the perspective of the Burakumin. Through a Buraku liberation reading, it is hoped that the possibility of interpreting the resurrection of Jesus as the liberating experience for the discriminated and marginalized people can be highlighted with the re-reading and presentation of the resurrected Jesus in the similitude of the discriminated and the marginalized, appearing before the discriminated and marginalized in the society