A model of Cellular Automata for the spatial and temporal analysis of Citrus Sudden Death with the fuzzy parameter

Citrus Sudden Death (CSD) is a disease that has affected sweet orange trees grafted on Rangpur lime in the south of Minas Gerais state and in the north of São Paulo state (Brazil). This is a worrying characteristic because the Rangpur lime responds to 85% of the Brazilian citrus rootstocks. This disease is believed to be caused by a virus transmitted by aphids (vector) of the citrus. In this work, we have adopted the Cellular Automata model (CA) to study the temporal evolution of the disease. We take into account the effect of the wind in the space covered by the aphid. To establish the relationship between the space covered by the aphid and the intensity of the wind, we have adopted the rule-based fuzzy system. Simulations were performed and compared to real data. Through the use of the mean absolute error (MAE) method, it was possible to verify a 70% of similarity between our model of data and the real one.     

Determination of total and available fractions of PAHs by SPME in oily wastewaters: overcoming interference from NAPL and NOM

Background, aim, and scope  

Polycyclic aromatic hydrocarbons (PAHs) are often found in oily wastewaters. Their presence is usually the result of human activities and has a negative effect on the environment. One important step in addressing this problem is to evaluate the effectiveness of PAH removal by biological processes since these are the most cost-effective treatments known today. Many techniques are presently available for PAH determination in wastewaters. Solid phase microextracion (SPME) is known to be one of the most effective techniques for this purpose. When analyzing complex matrices with substances such as natural organic matter (NOM) and non-aqueous phase liquids (NAPL), it is important to differentiate the free dissolved PAH from matrix-bonded PAH. PAHs associated with the bonded fraction are less susceptible to biological treatment. The present study concerns the development of a simple and suitable methodology for the determination of the freely dissolved and the total fraction of PAHs present in oily wastewaters. The methodology was then applied to an oily wastewater from a fuel station retention basin.     

Microbial fuel cell-induced production of fungal laccase to degrade the anthraquinone dye Remazol Brilliant Blue R

Environmental Chemistry Letters - The anthraquinone dye Remazol Brilliant Blue R is largely used in the textile industry. However, its removal from wastewaters is costly and complex. Many methods...     

Generation of new carbon–carbon and carbon–heteroatom bonds mediated by agro-waste extracts: a review

Agro-waste extracts are considered green solvents since they are easy to handle, readily accessible from natural waste feedstock, biodegradable and recyclable. Therefore, the employment of these extracts in reaction media has emerged as the most useful and eco-friendly alternative in modern organic chemistry. Here, we review recent developments for the generation of new carbon–carbon and carbon–heteroatom bonds mediated by agro-waste extracts. We show that these aqueous extracts have great applicability in several transformations, including condensations, oxidations, multicomponent and coupling reactions. The challenges and advantages on the use of water of agro-waste extracts in synthetic methodologies is also detail.

     

Changes in levels of essential elements in suckling rats exposed to zinc and mercury

The effect of mercury and its interaction with zinc on the content of essential metals in tissues from neonate rats was investigated. Three-day-old Wistar rats were treated with saline or 27 mg kg(-1)d(-1) ZnCl2 (s.c.) for five consecutive days. From the 8th to the 12th day of life, the rats received one daily dose of saline or 5.0 mg kg(-1) HgCl2 (s.c). Twenty-four hours after the last injection liver, kidneys and blood were collected for metal quantification. The HgCl(2) exposure induced alterations on metal levels, such as increase of Fe, Hg and Zn in liver, decrease of Fe and Mg and increase of Cu and Hg contents in kidneys. The Hg exposure also increased Hg levels in the blood. The treatment with ZnCl2, administered previously to HgCl2, partially prevented the increase of Fe in the liver, and not only prevented the decrease of renal Mg but also increased it to levels higher than those found in control group. The Zn-Hg rats also presented higher renal Cu levels, and showed partially lower blood and hepatic Hg levels and higher renal Hg levels. The pre-administration of Zn caused no severe alterations in levels of essential metals (Cu, Fe, Mg and Mn). In short, Zn appears to be an alternative treatment of Hg poisoning in young animals in comparison to chelating drugs since these have low metal selectivity.     

A Preliminary Index of Biotic Integrity for Monitoring the Condition of the Rio Paraiba do Sul,Southeast Brazil

The biodiversity of many Brazilian rivers is seriously threatened by industrial and municipal pollution, and Rio Paraiba do Sul, located between two major industrial centers is one example of this situation. A survey of the fish assemblage was conducted from October 1998 to September 1999 and the data were used to develop an index of biotic integrity (IBI). We sampled three zones in bracketing a large urban–industrial complex to evaluate water quality changes and the usefulness of the IBI as a monitoring tool. Water quality was classified as poor upstream of the effluent discharges, very poor near the discharges, and poor–fair downstream of the discharges, with this latter situation revealing the current biological capacity of the river. Physical and chemical habitat characteristics were also measured at each site to construct an independent environmental index to validate the IBI. The habitat and IBI indices were highly correlated, suggesting this IBI would be applicable to other large rivers in southeast Brazil.     

Comparative effects of the Roundup and glyphosate on mitochondrial oxidative phosphorylation

The potential toxicity of the herbicide Roundup and its fundamental substance (glyphosate) was tested in bioenergetic functions of isolated rat liver mitochondria. Roundup stimulates succinate-supported respiration twice, with simultaneous collapse of transmembrane electrical potential, while glyphosate used in the same concentrations does not induce any significant effect. Additionally, Roundup depresses state 3 respiration by about 40%, at 15 mM, whereas uncoupled respiration in the presence of FCCP is depressed by about 50%. Depression of uncoupled respiratory activity is mediated through partial inhibition of mitochondrial complexes II and III, but not of complex IV. The phosphorylative system was affected by both a direct and an indirect effect on the F0F1 ATPase activity. The addition of uncoupled concentrations of Roundup to Ca2+-loaded mitochondria treated with Ruthenium Red resulted in non-specific membrane permeabilization, as evidenced by mitochondrial swelling in isosmotic sucrose medium. Therefore, the uncoupling of oxidative phosphorylation is also related to the non-specific membrane permeabilization induced by Roundup. Glyphosate alone does not show any relevant effect on the mitochondrial bioenergetics, in opposition to Roundup formulation products. The differences in the toxicity observed could be either attributed to some products of Roundup or to a synergic effect of glyphosate and formulation products. Bearing in mind that mitochondria is provided with a variety of bioenergetic functions mandatory for the regulation of intracellular aerobic energy production and electrolyte homeostasis, these results question the safety of Roundup on animal health.     

Physical and numerical modelling of tsunami generation by a moving obstacle at the bottom boundary

This paper presents a study of the waves generated by a solid block landslide moving along a horizontal boundary. The landslide was controlled using a mechanical system in a series of physical experiments, and laser-induced fluorescence measurements resolved both spatial and temporal variations in the free surface elevation. During its constant-velocity motion, the landslide transferred energy into ‘trapped’ offshore-propagating waves within a narrow frequency band. The wave trapping is demonstrated by investigating the wave dispersion characteristics using a two-dimensional Fourier Transform. The first of the trailing waves broke at Froude numbers greater than or equal to 0.625. The parametric dependence of the largest-amplitude waves and the potential energy within the wave field are discussed. The experimental results were compared to the predictions of an incompressible Navier–Stokes solver with and without turbulence models. The numerical model under-predicted the measured wave amplitudes, although it accurately predicted the measured wave phasing. The turbulent model more accurately predicted the shapes of the trailing waves. Both experimental and numerical results confirmed that investigations into wave generation by submerged objects moving at constant velocity should also consider the initial acceleration of the object, as this affects the overall evolution of the wave field. The applicability of the horizontal-boundary results to more realistic field scenarios is discussed.