Safety and Effectiveness of Struvite from Black Water and Urine as a Phosphorus Fertilizer

To ensure food supply, phosphorus must be recycled, for which an appealing method is using struvite fertilizer from human excreta. One struvite from black water and another from urine were assessed for safety under Dutch regulations, and for effectiveness as P fertilizer in a maize field experiment and a literature review. Both struvites contained 12% P, 12% Mg, 6% N, and 0.5-1.5% of several micronutrients. Struvites did not exceed Dutch regulations for heavy metals or pathogens, and based on literature, organic toxins should be far below regulatory limits. In this study and 18 others, struvite appears to have similar effectiveness to soluble fertilizer. Early in the season, 200 kg P2O5 ha-1 of black water struvite and soluble phosphorus improved maize performance (

Citizens contributing in landscape in the Netherlands

With the continuing loss of landscape elements and open space, landscape management is gaining importance in tandem with the design of acceptable private and voluntary financing arrangements. Here, we analyze the awareness, involvement, socio-demographic characteristics and the contribution of citizens regarding the landscape. The contribution of citizens has been classified into three fields of activities. Data analysis is based on a survey among 1.060 inhabitants in and around three designated peri-urban areas in the Netherlands. The results show that these areas are well known, albeit on a limited scale. Most of the stated willingness of the inhabitants to contribute to the landscape has been related with their socio-demographic characteristics and to a less extent with their involvement with the landscape. To increase the willingness of citizens to contribute to the landscape the communication strategy may be improved

Stormwater Detention Systems with Effluent Filtration

The growing concern for water quality enhancement of our surface waters has led to changes in detention facility design. Providing a filter media for the effluent water to travel through before discharge into the environment has become an area of interest. Thus, detention facilities may be used for both water quality and quantity control. Different soil medias were studied for the potential of pollutant removal and infiltration rates usable in design work. Both laboratory and field experimentation were performed. A computer program was also developed to model stormwater movement through a swale detention system. This research was performed to examine filter media and to indicate the advisability of designing a combination of detention ponds and berms

Microarray Analysis of Late Response to Boron Toxicity in Barley (Hordeum vulgare L.) Leaves

DNA microarrays, being high-density and high-throughput, allow quantitative analyses of thousands of genes and their expression patterns in parallel. In this study, Barley1 GereChip was used to investigate transcriptome changes associated with boron (B) toxicity in a sensitive barley cultivar (Hordeum vulgare L. cv. Hamidye). Eight-day-old aseptically grown seedlings were subjected to 5 or 10 mM boric acid (B(OH)(3)) treatments for 5 days and expression profiles were determined with DNA microarrays using total RNA from leaf tissues. Among the 22,840 transcripts - each represented with a probe set on the GeneChip - 19,424 probe sets showed intensity values greater than 20(th) percentile in at least one of the hybridizations. Compared to control (10 mu M B(OH)(3)), 5 mM B(OH)(3) treatment resulted in differential expression of 168 genes at least by twofold. Moreover, 10 mM B(OH)(3) treatment resulted in at least twofold induction or reduction in expression of 312 transcripts. Among these genes, 37 and 61 exhibited significantly (P <0.05) altered levels of expression under 5 and 10 mM B(OH)(3) treatments, respectively. Differentially expressed genes were characterized using expression-based clustering and HarvEST:Barley. Investigations of expression profiles revealed that B toxicity results in global changes in the barley transcriptome and networks of signaling or molecular responses. A noticeable feature of response to 8 was that it is highly interconnected with responses to various environmental stresses. Additionally, induction of jasmonic acid related genes was found to be an important late response to B toxicity. Determination of responsive genes will shed light on successive studies aiming to elucidate molecular mechanism of B toxicity or tolerance. To the best of our knowledge, this is the first report on global expression analysis of barley seedlings under B toxicity

Dusty tails of evaporating exoplanets. II. Physical modelling of the KIC 12557548b light curve

Evaporating rocky exoplanets, such as KIC 12557548b, eject large amounts of dust grains, which can trail the planet in a comet-like tail. When such objects occult their host star, the resulting transit signal contains information about the dust in the tail. We aim to use the detailed shape of the Kepler light curve of KIC 12557548b to constrain the size and composition of the dust grains that make up the tail, as well as the mass loss rate of the planet. Using a self-consistent numerical model of the dust dynamics and sublimation, we calculate the shape of the tail by following dust grains from their ejection from the planet to their destruction due to sublimation. From this dust cloud shape, we generate synthetic light curves (incorporating the effects of extinction and angle-dependent scattering), which are then compared with the phase-folded Kepler light curve. We explore the free-parameter space thoroughly using a Markov chain Monte Carlo method. Our physics-based model is capable of reproducing the observed light curve in detail. Good fits are found for initial grain sizes between 0.2 and 5.6 micron and dust mass loss rates of 0.6 to 15.6 M_earth/Gyr (2-sigma ranges). We find that only certain combinations of material parameters yield the correct tail length. These constraints are consistent with dust made of corundum (Al2O3), but do not agree with a range of carbonaceous, silicate, or iron compositions. Using a detailed, physically motivated model, it is possible to constrain the composition of the dust in the tails of evaporating rocky exoplanets. This provides a unique opportunity to probe to interior composition of the smallest known exoplanets.Comment: 18 pages, 11 figures, A&A accepte