Using an inverse modelling approach to evaluate the water retention in a simple water harvesting technique

In arid and semi-arid zones, runoff harvesting techniques are often applied to increase the water retention and infiltration on steep slopes. Additionally, they act as an erosion control measure to reduce land degradation hazards. Nevertheless, few efforts were observed to quantify the water harvesting processes of these techniques and to evaluate their efficiency. In this study, a combination of detailed field measurements and modelling with the HYDRUS-2D software package was used to visualize the effect of an infiltration trench on the soil water content of a bare slope in northern Chile. Rainfall simulations were combined with high spatial and temporal resolution water content monitoring in order to construct a useful dataset for inverse modelling purposes. Initial estimates of model parameters were provided by detailed infiltration and soil water retention measurements. Four different measurement techniques were used to determine the saturated hydraulic conductivity (<I>K</I><sub>sat</sub>) independently. The tension infiltrometer measurements proved a good estimator of the <I>K</I><sub>sat</sub> value and a proxy for those measured under simulated rainfall, whereas the pressure and constant head well infiltrometer measurements showed larger variability. Six different parameter optimization functions were tested as a combination of soil-water content, water retention and cumulative infiltration data. Infiltration data alone proved insufficient to obtain high model accuracy, due to large scatter on the data set, and water content data were needed to obtain optimized effective parameter sets with small confidence intervals. Correlation between the observed soil water content and the simulated values was as high as <I>R</I><sup>2</sup>=0.93 for ten selected observation points used in the model calibration phase, with overall correlation for the 22 observation points equal to 0.85. The model results indicate that the infiltration trench has a significant effect on soil-water storage, especially at the base of the trench

Determinação de coeficientes de cultura para o milho durante um experimento de evapotranspiração em um oxisol do Brasil

Soil water balance components were measured during two periods (from 1989 to 1991) on a Dark Red Latosol (oxisol) in Piracicaba,SP, Brazil. The change in soil water storage and the soil water fluxes at the lower limit of the rooting zone were calculated for a transect of 25 observation plots. Hydraulic head gradients were determined by tensiometer measurements. Soil water flux densities were estimated through Darcy's equation. The actual evapotranspiration of the crops and weeds and the actual evaporation of bare soil were obtained from the water balance equation and this for two periods under different crop rotations. For the first period the sequence was bare soil-corn-weeds and for the second period it was stubble mulch-weeds-corn. For assessing the crop coefficients the potential evapotranspiration was calculated according to two different methods. The first method was based on the modified Penman equation with grass as a reference crop, to obtain this way reference coefficients, and the second method was based on the pan "A" evaporation data in order to obtain pan coefficients. These coefficients were compared with the tabulated crop coefficients. In general when there was no shortage of water during the corn growth, the crop coefficients k c"A" and k c ref were very close to the k c values.Os componentes do balanço hídrico foram medidos durante dois períodos (de 1989 a 1991) em terra roxa estruturada, em Piracicaba,SP, Brasil. As variações de armazenamento de água e os fluxos de água no solo no limite inferior da zona radicular foram calculados para uma transeção de 25 parcelas experimentais. Gradientes hidráulicos foram determinados por meio de medidas tensiométricas. Densidades de fluxo de água foram estimadas através da equação de Darcy. A evapotranspiração atual das culturas e das ervas daninhas e a evaporação atual do solo nú foram obtidas da equação do balanço hídrico, para dois períodos, sob diferentes rotações de cultura. Para o primeiro período a seqüência foi solo nú - milho - ervas daninhas e para o segundo cobertura morta - ervas daninhas - milho. Para determinar os coeficientes de cultura, a evapotranspiração potencial foi calculada por dois métodos. O primeiro foi baseado na equação de Penman modificada, com a grama como cobertura de referência, obtendo assim os coeficientes de referência, e o segundo baseado no tanque de evaporação tipo classe "A", obtendo os coeficientes de tanque. Estes coeficientes foram comparados com os coeficientes de cultura tabulados. De uma forma geral, em períodos sem falta de água para a cultura, os coeficientes de referência e de tanque se assemelharam bastante aos coeficientes de cultura

Alien macrocrustaceans in freshwater ecosystems in the eastern part of Flanders (Belgium)

Biological invasions of freshwater macroinvertebrates are gaining more and more interest because the ecological and economical impact of some of these species is high. Since crustacean taxa appear to be successful groups invading new areas, an inventory of the macrocrustaceans in Flanders was made. At least 22 freshwater macrocrustacean species have been reported from Flemish water bodies. A detailed study of six canals, one small artificial watercourse and one natural river in the eastern part of Flanders revealed that invaders such as Dikerogammarus villosus, Gammarus tigrinus and Chelicorophium curvispinum are already quite common. Especially D. villosus is currently rapidly expanding and has a serious impact on native and other exotic gammarid species. Based on observations in neighbouring countries, several additional species are expected to arrive in the near future. A follow-up of the alien species together with a monitoring scheme to detect new incoming species is valuable to estimate the size of the problem and to be able to closely follow their ecological and economical impact

ECOPLAN-SE: Ruimtelijke analyse van ecosysteemdiensten in Vlaanderen, een Q-GIS plugin

ECOPLAN-SE is een ruimtelijk expliciete tool (QGIS) voor het beoordelen van de impact van landgebruikveranderingen op de levering van ecosysteemdiensten. De ontwikkeling van deze tool kadert in het het SBO-project “ECOPLAN” (Planning for Ecosystem Services). ECOPLAN ontwikkelt ruimtelijk expliciete informatie en instrumenten voor de beoordeling van ecosysteemdiensten. Het ontwerpt instrumenten voor de evaluatie van functionele ecosystemen als een kostenefficiënte strategie om de landgebruiksefficiëntie en milieukwaliteit te verbeteren. Het ontwikkelt open source eindproducten voor het identificeren, kwantificeren, waarderen, valideren en monitoren van ecosysteemdiensten. Deze producten kunnen door administraties en consultants worden ingezet in projectontwikkeling, kosten-baten analyses, milieueffecten rapportering, etc

Virtual money, practices and moral orders in Second Life

Virtual monies present a limit case in debates about money's moral and political entanglements between sociologists, anthropologists, and economists. Digitized virtual monies seem ephemeral, almost ideal typical examples of money as a pure medium of exchange. This paper begins with the premise that virtual monies are as value-laden and morally entangled as any other form of money. This assertion is demonstrated by exploring how one type of virtual money, the Linden dollar (L$), and some of its associated practices are bound up with research participants' moral categories and judgments in the virtual world of Second Life (SL). Participants' accounts of virtual money practices are linked to moral attributes, sometimes in stark ‘good’ or ‘bad’ dichotomies, but also in more nuanced terms. These framings reproduce classifications of people and practices along a continuum with virtuousness at one end and maliciousness or harm at the other, passing through various states of possible moral dubiousness. For respondents, these two judgments go together; people are what they do with money. As a result, respondents decide what ‘people like that’ deserve. Evaluating someone's money practices means assessing the person. Participants' accounts of Linden dollar practices overlap with explanations of what SL is and how residents should live there. In SL, money is a form of material culture through which appropriate ways of being in the world are debated and reproduced

The nuclear immune receptor RPS4 is required for RRS1SLH1-dependent constitutive defense activation in Arabidopsis thaliana

Plant nucleotide-binding leucine-rich repeat (NB-LRR) disease resistance (R) proteins recognize specific ‘‘avirulent’’ pathogen effectors and activate immune responses. NB-LRR proteins structurally and functionally resemble mammalian Nod-like receptors (NLRs). How NB-LRR and NLR proteins activate defense is poorly understood. The divergently transcribed Arabidopsis R genes, RPS4 (resistance to Pseudomonas syringae 4) and RRS1 (resistance to Ralstonia solanacearum 1), function together to confer recognition of Pseudomonas AvrRps4 and Ralstonia PopP2. RRS1 is the only known recessive NBLRR R gene and encodes a WRKY DNA binding domain, prompting suggestions that it acts downstream of RPS4 for transcriptional activation of defense genes. We define here the early RRS1-dependent transcriptional changes upon delivery of PopP2 via Pseudomonas type III secretion. The Arabidopsis slh1 (sensitive to low humidity 1) mutant encodes an RRS1 allele (RRS1SLH1) with a single amino acid (leucine) insertion in the WRKY DNA-binding domain. Its poor growth due to constitutive defense activation is rescued at higher temperature. Transcription profiling data indicate that RRS1SLH1-mediated defense activation overlaps substantially with AvrRps4- and PopP2-regulated responses. To better understand the genetic basis of RPS4/RRS1-dependent immunity, we performed a genetic screen to identify suppressor of slh1 immunity (sushi) mutants. We show that many sushi mutants carry mutations in RPS4, suggesting that RPS4 acts downstream or in a complex with RRS1. Interestingly, several mutations were identified in a domain C-terminal to the RPS4 LRR domain. Using an Agrobacterium-mediated transient assay system, we demonstrate that the P-loop motif of RPS4 but not of RRS1SLH1 is required for RRS1SLH1 function. We also recapitulate the dominant suppression of RRS1SLH1 defense activation by wild type RRS1 and show this suppression requires an intact RRS1 P-loop. These analyses of RRS1SLH1 shed new light on mechanisms by which NB-LRR protein pairs activate defense signaling, or are held inactive in the absence of a pathogen effector

EFFECT OF PHOTON TREATMENT ON STRUCTURE OF NIOBIUM OXIDE FILMS

In this work, we investigate changes in the phase composition, morphology, and structural changes during the photonic treatment of films obtained in the process of ion-beam sputtering of an Nb2O5 target. It was found that the initial films have an amorphous structure; at an irradiation energy of ~ 1.Работа была выполнена при поддержке государственного задания (N FZGM-2020-0007)