Bioavailability and health risk of pollutants around a controlled landfill in Morocco: Synergistic effects of landfilling and intensive agriculture.

Toxic contamination of agricultural soils by trace metal(oid)s can pose detrimental effects on human health and agroecological systems. In this view, the current research explored total and available metal(oid)s in surface soils and assessed the associated hazards using pollution indices, PMF modeling, PCA, and Montecarlo probabilistic human risk assessment with 10,000 repetitions. The mean concentrations of Cd, Pb, As, Cr, Ni, Cu, Zn, and Fe were 0.89, 24.86, 1.81, 19.10, 25.44, 7.98, 49.12 and 6183.32 mg kg-1 dry weight, respectively. These findings highlighted that the concentration of pollutants exceeded the values measured in the geochemical background. Soil enrichment by heavy metal (oid)s was confirmed by analyzing available fractions using DTPA ,CaCl2 and enrichment factor (EF). Additionally, pollution indicators (Igeo, PLI, and PERI) displayed significant contamination levels, with a higher ecological risk. Matrix Factorization (PMF) receptor and multivariate statistical analysis reflected that anthropogenic activities, particularly landfilling and agricultural practices were the main causes of the contamination. Furthermore, probabilistic and deterministic human risk assessments showed that carcinogenic risks exceeded the threshold values (10-4) set by the USEPA. Consequently, it is crucial to implement continuous monitoring and supervision of landfill sites to prevent additional pollution. These measures should be integrated into the management plans for waste management.

Desarrollo de un modelo de planeación financiera para una compañía de alimentos utilizando simulación Monte Carlo / Development of a financial planning model for the food's company using Monte Carlo simulation / Desenvolvimento de um modelo de planeamento financeiro para a empresa do ramo alimentar utilizando simulação Monte Carlo

RESUMEN El objetivo es desarrollar un modelo de planeación financiera que permita calcular las ganancias probables de una compañía de alimentos en Colombia, en un horizonte temporal de seis años. La metodología utilizada es el Valor Presente Neto de sus flujos de caja libre, calculados a partir de 38 variables de entrada y de proceso que recogen el aspecto macroeconómico, las políticas financieras y los estados contables. Se realizaron 10.000 iteraciones con la técnica de simulación Montecarlo. Los resultados de la simulación indican que sus ganancias probables están entre $278.293 millones y $449.934 millones con un nivel de confianza del 90%. El análisis de sensibilidad del plan financiero permite concluir que la compañía debe reformular sus políticas financieras relacionadas con la administración del capital de trabajo, dado que la cartera y principalmente los inventarios tienen una influencia negativa sobre el VPN, según los coeficientes de regresión. CLASIFICACIÓN JEL B41, C15

ABSTRACT The goal is to develop a financial planning model that allows calculating the probable profits of a food company in Colombia, in a time horizon of six years. The methodology used is the Net Present Value of its Free Cash Flow, calculated from 38 input and process variables that include the macroeconomic aspect, financial policies and financial statements. 10.000 iterations were carried out with the Montecarlo simulation technique. The simulation results indicate that its probable profits are between $278.293 million and y $449.934 million with a confidence level of 90%. The sensitivity analysis of the financial plan allows to conclude that the company should reformulate its financial policies related to the management of working capital, since the debt clients and mainly the inventories has a negative influence on the Net Present Value, according the regression coefficients. JEL CLASSIFICATION B41, C15

RESUMO O objectivo é desenvolver um modelo de planeamento financeiro que permita calcular os prováveis lucros de uma empresa alimentar na Colômbia, num horizonte temporal de seis anos. A metodologia utilizada é o Valor Presente Líquido dos seus fluxos de caixa livres, calculado a partir de 38 variáveis de entrada e de processo que recolhem o aspecto macroeconómico, as políticas financeiras e as declarações contabilísticas. Um total de 10.000 iterações foram realizadas utilizando a técnica de simulação de Monte Carlo. Os resultados da simulação indicam que os seus prováveis lucros se situam entre $278,293 milhões e $449,934 milhões com um nível de confiança de 90%. A análise de sensibilidade do plano financeiro permite concluir que a empresa deve reformular as suas políticas financeiras relacionadas com a gestão do capital de exploração, uma vez que a carteira e principalmente os inventários têm uma influência negativa no VPL, de acordo com os coeficientes de regressão. CLASSIFICAÇÃO JEL B4I, CI5

Addressing the surface coverage of Au nano-agglomerates and the electrochemical properties of modified carbon paste electrodes: Experimental and theoretical studies on ascorbic acid oxidation.

This article shows the formation of Au nano-agglomerates when increasing amounts of gold nanoparticles (AuNP) are incorporated into carbon paste electrodes. The surface coverage by this agglomerates is related to the electro-oxidation of a widely studied redox compound, ascorbic acid (AA); by analyzing the effect on the oxidation peak potential (Ep,a) and oxidation peak current (ip,a). The effects of pH and scan rate on the Ep,a and ip,a were investigated by cyclic voltammetry, and enabled to estimate the transfer coefficient and the number of electrons involved in the rate determining step (αnα), the standard heterogeneous rate constant (ks), and the diffusion coefficient of the redox compound, being 0.52 and 3.5 × 10-3 cm s-1 and 6.3 × 10-6 cm2 s-1, respectively. On the other hand, the sensing ability of the modified electrode was evaluated, obtaining a sensitivity of (63.2 ± 2.5) µA mM-1, a detection limit of 2.7 µM and a quantification limit of 8.9 µM. Additionally, a computational model based on lattice-gas model and Monte Carlo simulations in the Grand Canonical Ensemble was proposed in order to reproduce the behavior of the system, in terms of ip,a and Ep,a shift with increasing surface coverage by Au nano-agglomerates.

Assessing the stochastic variability of the Benefit-Cost ratio in roadway safety management.

Road Agencies set quantitative targets and adopt related road safety strategies within the priorities and the available resources at the time of an economic crisis. In this framework, benefit-cost analyses (BCA) are carried out to support the decision making process and alternative measures are ranked according to their expected benefit and benefit-cost ratio calculated using a Safety Performance Function (SPF) and Crash Modification Factors (CMFs) as predictors of future safety performances. Due to the variance of CMFs and crash frequency we are uncertain what the benefits of some future actions will be. The chance of making wrong decisions depends on the size of the standard deviation of the probability distribution of the considered stochastic variables. To deal with the uncertainty inherent in the decision making process, a reliability based assessment of benefits must be performed introducing a stochastic approach. In the paper the variability of the CMFs, the predicted number of crashes and the crash costs are taken into account in a reliability based BCA to address improvements and issues of an accurate probabilistic approach when compared to the deterministic results or other approximated procedures. A case study is presented comparing different safety countermeasures selected to reduce crash frequency and severity on sharp curves in motorways. These measures include retrofitting of old safety barriers, delineation systems and shoulder rumble strips. The methodology was applied using the Monte Carlo simulations to calculate the probability of failure of BCA statements. Results and comparisons with alternative approaches, like the one proposed in the HSM, are presented showing remarkable differences in the evaluation of outcomes which can be achieved.

A High Diffusive Model for Nanomaterials.

Considerable attention is today devoted to the engineering of films widely used in photocatalytic, solar energy converters, photochemical and photoelectrochemical cells, dye-sensitized solar cells (DSSCs), to optimize electronic time response following photogeneration. However, the precise nature of transport processes in these systems has remained unresolved. To investigate such aspects of carrier dynamics, we have suggested a model for the calculation of correlation functions, expressed as the Fourier transform of the frequency-dependent complex conductivity σ(ω). Results are presented for the velocity correlation functions, the mean square deviation of position and the diffusion coefficient in systems, like TiO2 and doped Si, of large interest in present devices. Fast diffusion occurs in short time intervals of the order of few collision times. Consequences for efficiency of this fast response are discussed in relation to nanostructured devices.