Geostatistics as a tool to improve the natural background level definition: An application in groundwater

The Natural Background Level (NBL), suggested by UE BRIDGE project, is suited for spatially distributed datasets providing a regional value that could be higher than the Threshold Value (TV) set by every country. In hydrogeochemically dis-homogeneous areas, the use of a unique regional NBL, higher than TV, could arise problems to distinguish between natural occurrences and anthropogenic contaminant sources. Hence, the goal of this study is to improve the NBL definition employing a geostatistical approach, which reconstructs the contaminant spatial structure accounting geochemical and hydrogeological relationships. This integrated mapping is fundamental to evaluate the contaminant's distribution impact on the NBL, giving indications to improve it. We decided to test this method on the Drainage Basin of Venice Lagoon (DBVL, NE Italy), where the existing NBL is seven times higher than the TV. This area is notoriously affected by naturally occurring arsenic contamination. An available geochemical dataset collected by 50 piezometers was used to reconstruct the spatial distribution of arsenic in the densely populated area of the DBVL. A cokriging approachwas applied exploiting the geochemical relationships among As, Fe andNH4+. The obtained spatial predictions of arsenic concentrationswere divided into three different zones: i) areas with an As concentration lower than the TV, ii) areas with an As concentration between the TV and the median of the values higher than the TV, and iii) areas with an As concentration higher than the median. Following the BRIDGE suggestions, where enough samples were available, the 90th percentile for each zone was calculated to obtain a local NBL (LNBL). Differently from the original NBL, this local value gives more detailed water quality information accounting the hydrogeological and geochemical setting, and contaminant spatial variation. Hence, the LNBL could give more indications about the distinction between natural occurrence and anthropogenic contamination

Subsoil geostatistical modeling as tool for hydrogeological modeling: transitional probability approach applied upon a heterogeneous site

Hydrogeological modeling, 3D simulation, Venice lagoon, reactive transport numerical mode

Evolutionary Game Dynamics for Crowd Behavior in Emergency Evacuations

This paper studies the problem of a large group of individuals that has to get to a safety exit in the context of high-stress emergency evacuations. We model this problem as a discrete-state continuous-time game, where the players update their strategies to reach the exit within a defined time horizon, whilst avoiding undesirable situations such as congestion and being trampled. The proposed model builds on crowd dynamics in a two-strategy game theoretic context, which we extend to include aspects of crowd behavior originating in sociology and psychology, and in the analogous studies performed in immersive virtual environments. The main contribution of this paper is threefold: i) we propose a novel game formulation of the model in terms of the population distribution across three strategies, and provide a link with prospect theory; ii) we study the equilibria of the system and their stability via Lyapunov stability theory of nonlinear systems; iii) we extend the model to a multi-population setting, where each population represents the group of players at a certain distance from the exit

Hexavalent Chromium: Analysis of the Mechanism of Groundwater Contamination in a Former Industrial Site in the Province of Vicenza (Northern Italy)

The study consisted in the analysis of the mobilization mechanisms of hexavalent chromium (Cr(VI)) into groundwater from a decommissioned contaminated factory. The site is located in the Province of Vicenza and formerly was a chrome-plating plant. The subsoil consists predominantly of gravelly deposits with a thickness of at least one hundred meters. An unconfined aquifer is present with water table at about 23 m depth bgl. During the seven years of monitoring (2008-2014), the fluctuation of groundwater level was more than 6 m; hydraulic conductivity is about 1.0E-03 m/s and groundwater seepage velocity about 12 m/day. At the area of the source of contamination, the unsaturated soil is contaminated by hexavalent chromium throughout the thickness: concentrations range from 200 to 500 mg/kg. At the bottom of zone of groundwater level fluctuation, the hexavalent chromium concentration decreases to below the detection limit. The available data (e.g. hexavalent chromium concentrations in groundwater, groundwater level, local rainfall) give the opportunity to assess the effects, on the magnitude of groundwater contamination, of the effective infiltration versus the fluctuation of groundwater level. The main analysis was performed on a statistical basis, in order to find out which of the two factors was most likely related to the periodic peaks of hexavalent chromium concentration in groundwater. Statistical analysis results were verified by a mass balance. Data show that at the site both the effective infiltration through the unsaturated zone and the leaching of soil contaminated by groundwater, when it exceeds a certain piezometric level, lead to peak concentrations of hexavalent chromium, even if with characteristics and effects different

Analysis of saccharification in Brachypodium distachyon stems under mild conditions of hydrolysis

Analysis of saccharification in Brachypodium distachyon stems unde

High-throughput Saccharification Assay for Lignocellulosic Materials

Polysaccharides that make up plant lignocellulosic biomass can be broken down to produce a range of sugars that subsequently can be used in establishing a biorefinery. These raw materials would constitute a new industrial platform, which is both sustainable and carbon neutral, to replace the current dependency on fossil fuel. The recalcitrance to deconstruction observed in lignocellulosic materials is produced by several intrinsic properties of plant cell walls. Crystalline cellulose is embedded in matrix polysaccharides such as xylans and arabinoxylans, and the whole structure is encased by the phenolic polymer lignin, that is also difficult to digest 1. In order to improve the digestibility of plant materials we need to discover the main bottlenecks for the saccharification of cell walls and also screen mutant and breeding populations to evaluate the variability in saccharification 2. These tasks require a high throughput approach and here we present an analytical platform that can perform saccharification analysis in a 96-well plate format. This platform has been developed to allow the screening of lignocellulose digestibility of large populations from varied plant species. We have scaled down the reaction volumes for gentle pretreatment, partial enzymatic hydrolysis and sugar determination, to allow large numbers to be assessed rapidly in an automated system

EVALUACION DEL RENDIMIENTO DE SORGO VARIEDAD CNIA-INTA BAJO DISTINTAS FUENTES DE SUMINISTRO DEL NITROGENO

Given the importance of sorghum for Nicaraguan small and medium farmers and their use for grain production, the National Agrarian University (UNA), and INTSORMIL Program, since year 2000 have been evaluating sorghum varieties and land races. After three years of results, the good productive variety CNIA-INTA was selected to be evaluated at different low levels of nitrogen fertilization under the practices of the small farmers. An alternative method of fertilization that includes the use of biomass of Vigna radiata L. as source of N was also evaluated. Three trials were established during the second season of 2004. One in Tisma, Department of Masaya, the second at the Experimental research west Center (CEO), located in Posoltega, Department of Chinandega and the third in San Ramón, Matagalpa, in the community of Guadalupe, located 10 km apart from Matagalpa. A randomized completed block design with four replications was used; each plot was shaped by seven rows 5 m. long, separated 0.6 m. between each other. The four central rows were used as main plot to collect information. The analysis of variance showed highly significant differences between localities and treatments for grain yield. A significant interaction was determined between localities x treatment, on grain yield. Concerning grain yield, the whole amount of Urea at planting time (6 078 kg ha -1) and the use of Mungo (5 655 kg ha-1) were statistically equal and both differed from the fractioned urea treatment (4488 kg ha-1).Considering localities, Tisma shows the largest yield with (7,259 kg ha -1), with experimental research west center with the smaller yield (3 932 kg ha-1). There were not differences among treatments concerning weight of thousand grains, but in the case of localities, San Ramon, showed the larger weight (26.7 g). Biomass production was not affected by the way on how nitrogen was distributed. However, when Mungo was applied lightly overcome treatment with chemical fertilizers. The same behavior was obtained for this variable among localities. There was interaction between localities and treatments in the case of grain yield. Tisma, was the locality where Sorghum shows the higher yield. It is interesting that treatment using Mungo reach the higher yield in San Ramón, and the second in the remaining localities studied.DOI: 10.5377/calera.v10i14.24Dada la importancia del cultivo de sorgo para pequeños y medianos productores nicaragüenses y su utilización para la producción de grano, la Universidad Nacional Agraria y el Programa INTSORMIL, desde el año 2000 evaluaron distintos materiales de sorgo. Después de tres años de resultados, se seleccionó la variedad CNIA-INTA por su buen rendimiento de grano para ser sometido a niveles bajos de fertilización (práctica del pequeño productor) y a un método alternativo que incluyen el uso de abono verde (Vigna radiata L.), como fuente de N. Con este propósito tres ensayos se establecieron en el ciclo de postrera del 2004. El primero en Tisma, Departamento de Masaya, el segundo en el Centro Experimental de Occidente (CEO) en el Municipio de Posoltega, departamento de Chinandega y el tercero en San Ramón, Matagalpa, en la Comunidad Guadalupe, ubicada a 10 km. de la cabecera departamental. Se utilizó un diseño de bloques completos al azar (BCA), con cuatro repeticiones. Cada parcela constituida de siete surcos de cinco m de largo, separados a 0.60 m. Se utilizaron los cuatro surcos centrales como parcela útil para muestreos de las variables a evaluar. El análisis de varianza mostró diferencias altamente significativas entre localidades y tratamientos y para localidad x tratamiento para el rendimiento de grano (RG). Los tratamientos urea (toda) a la siembra (6 078 kg ha-1) y Mungo (5 655 kg ha-1) fueron estadísticamente iguales y ambos se diferenciaron del tratamiento urea fraccionada (4 488 kg ha-1). Entre localidades, Tisma obtuvo el mayor rendimiento con 7,259 kg -1 superior al obtenido en el CEO, con 3 933 kg ha-1. No se encontraron diferencias entre tratamientos en el peso de mil granos y rendimiento de biomasa (RB), sin embargo, en San Ramón se obtuvo el mayor peso (26.74 g) y el menor en CEO (23.78 g). La forma de suministrar nitrógeno no tuvo efecto sobre la materia seca producida, sin embargo, el tratamiento con mungo, superó ligeramente a la biomasa producida con fertilización química. El mismo comportamiento se obtuvo para esta variable entre localidades. Se obtuvo interacción positiva entre localidad x tratamiento, siendo en Tisma donde se alcanzan los mayores rendimientos cuando se aplica el N 30 días después de la siembra (dds). El uso de mungo, presentó el segundo mejor rendimiento en las dos localidades antes mencionadas.DOI: 10.5377/calera.v10i14.2

Optimization of biomass pretreatments using fractional factorial experimental design

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOPretreatments are one of the main bottlenecks for the lignocellulose conversion process and the search for cheaper and effective pretreatment methodologies for each biomass is a complex but fundamental task. Here, we used a 2ν5−1 fractional factorial des11FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO2016/13602-72016/10955-62016/05636-

Geometry of Frictionless and Frictional Sphere Packings

We study static packings of frictionless and frictional spheres in three dimensions, obtained via molecular dynamics simulations, in which we vary particle hardness, friction coefficient, and coefficient of restitution. Although frictionless packings of hard-spheres are always isostatic (with six contacts) regardless of construction history and restitution coefficient, frictional packings achieve a multitude of hyperstatic packings that depend on system parameters and construction history. Instead of immediately dropping to four, the coordination number reduces smoothly from $z=6$ as the friction coefficient $\mu$ between two particles is increased.Comment: 6 pages, 9 figures, submitted to Phys. Rev.

USO EFICIENTE DEL NITROGENO POR 16 LINEAS DE SORGO EN NICARAGUA

El nitrógeno es uno de los factores que limita la producción del sorgo por su alta demanda y alto costo del fertilizante. Con el objetivo de evaluar distintos materiales de sorgo en Nicaragua, un experimento con 14 líneas de sorgo de ICRISAT, Jocoro de El Salvador y el testigo local Pinolero-1, se plantaron a cero y 37 kg N/ha en seis ambientes. Los ambientes eran combinaciones de localidad/año incluidos; El Plantel 2003 y 2004, CEO-Posoltega 2003 y 2004, y Tisma y San Isidro en 2004. Se utilizo un diseño de bloques completos al azar, los tratamientos se aleatorizaron en las parcelas. La línea se ubico en la parcela grande y el nivel de nitrógeno en las subparcelas. El rendimiento de grano, rastrojo, concentración de N y extracción por grano y rastrojo, y el uso eficiente del N por grano y biomasa fueron determinados. Sin aplicación de N, ninguna línea de sorgo rindió mejor que Pinolero-1, mientras ICSVLM-93079 produjo 0.7 tm/ha más en grano con aplicación de N. Pinolero-1 obtuvo el uso eficiente de N más alto con 46 kg grano y 121 kg biomasa por unidad de N aplicado. ICSVLM-93079 presento la respuesta más alta en rendimiento con 35 kg N/ha. La aplicación de N aumentó el rendimiento de grano en 0.8 tm/ha y de rastrojo en 1.9 tm/ha. Los programas de mejoramiento de sorgo en Nicaragua, deben incluir ICSVLM-93079 para aumentar rendimiento de grano. Los productores deben usar el fertilizante N para aumentar rendimientos de grano y de rastrojo. Abreviaturas: N, nitrógeno, UEN, uso eficiente de nitrógeno, IR, incremento de rendimiento en kg de grano por kg de N aplicado