Special issue on the 13th international conference on computational management science

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La escuela nueva y Célestin Freinet

No incluye resumenGrado en Educación Primari

How informative are financial asset prices in Spain?

El objetivo de este trabajo es analizar el contenido informativo, en el caso español, de los precios de diversos activos financieros (tipos de interes, diferenciales, precios de acciones y tipos de cambio) con respecto de la evolucion futura de tres variables macroeconomicas claves para un banco central (tasa de inflacion, crecimiento economico y tipo de interes a tres meses). Para valorar los diferentes indicadores se consideran tras aproximaciones alternativas. De acuerdo con los resultados, ninguno de los indicadores considerados parece mantener una relacion empirica estable con inflacion, PIB o tipo de interes a tres meses. No obstante, desde el punto de vista de la politica monetaria, pueden ser utiles como indicadores cualitativos que complementen la informacion cuantitativa aportada por otros indicadores no financieros y como indicadores de expectativas y, por tanto, de posibles problemas de credibilidad o de interprestacion de las acciones de politica monetaria. Contiene graficos, cuadros y bibliografia. (jah) (mac

Percepción del consumo de cannabis en España: estudio del enfoque a través del ámbito científico y de la prensa

Introduction: In Spain, the recreational use of cannabis is illegal. This illegality is once again part of a social debate in which certain political groups support a justified legalization based on economic benefits against some medical opinions that do not recommend the consumption decriminalization. Objective: This review aims to identify the approach given to consumption in Spain, both in the scientific field and in a more general one as the written press. The coherence or disagreement between the detected approaches can contribute to determinate if legalization will be a reality soon. Method: An analysis of scientific and non-scientific publications is carried out using three forms of research: a specialized search tool (Google Scholar), two national newspapers in their digital version (ABC and El País) and an online scientific citation indexing service (Web of Science). Results: The journalistic and the scientific field coincide in a negative approach regarding the cannabis consumption; in addition, its content turns out to be very focused on society. Conclusions: The high consumption of cannabis among the Spanish population despite the negative approach indicates a failure in the communication related with this problematic.Introducción: En España, el consumo recreativo de cannabis es ilegal. Esta ilegalidad ha vuelto a formar parte de un debate social en el que ciertas formaciones políticas se posicionan a favor de una legalización justificada por los beneficios económicos en contra de ciertas opiniones médicas que no recomiendan la despenalización del consumo. Objetivo: Esta revisión pretende identificar el enfoque que se da al consumo en España, tanto en el ámbito científico como en uno más generalista, como es la prensa escrita. La coherencia o el desacuerdo entre los enfoques detectados puede contribuir a determinar si la legalización será una realidad en el futuro. Método: Se desarrolla un análisis de publicaciones científicas y no científicas empleando tres formas de búsqueda: un motor de búsqueda especializado (Google Scholar), dos periódicos nacionales en su versión digital (ABC y El País) y un gestor bibliográfico de literatura científica (Web of Science). Resultados: El ámbito periodístico y el científico coinciden en un enfoque negativo respecto al consumo de cannabis; además, su contenido resulta estar muy enfocado a la sociedad. Conclusión: El consumo elevado de cannabis entre la población española, a pesar del enfoque negativo, indica un fallo en la comunicación relativa a esta problemática

A computational comparison of several formulations for the multi-period incremental service facility location problem

The Multi-period Incremental Service Facility Location Problem, which was recently introduced, is a strategic problem for timing the location of facilities and the assignment of customers to facilities in a multi-period environment. Aiming at finding the strongest formulation for this problem, in this work we study three alternative formulations based on the so-called impulse variables and step variables. To this end, an extensive computational comparison is performed. As a conclusion, the hybrid impulse–step formulation provides better computational results than any of the other two formulations

Nitrogen use efficiency and residual effect of fertilizers withnitrification inhibitors

Blending fertilizers with nitrification inhibitors (NI) is a technology to reduce nitrogen (N) losses. The application of NI could increase the soil N supply capacity over time and contribute to an enhancement of N-fertilizer recovery in some cropping systems. During two seasons, a field experiment with maize (Zea mays L.) was fertilized with ammonium sulfate nitrate (ASN) and DMPP (3,4 dimethylpyrazole phosphate) blended ASN (ENTEC) at two levels (130 and 170 kg N ha-1) under Mediterranean conditions. A control treatment with no added N fertilizer was also included. Maize yield, grain quality, nutritional state and fertilizer use efficiency were evaluated. Due to the observation of a soil residual effect, a non-fertilized sunflower (Helianthus annuus L.) was planted in the same plots to study the cumulative effect during a third experimental season. Laboratory determinations were performed in order to elucidate the possible sources of residual N. The second year, DMPP application allowed a 23% reduction of the fertilizer rate without decreasing crop yield or grain quality. In addition, the non-fertilized sunflower planted after the maize scavenge more N in treatments previously treated with ENTEC than with traditional fertilizers, increasing N use efficiency in the cropping systems. After DMPP application, N was conserved in non-ready soil available forms during at least one year and subsequently released to meet the sunflower crop demand. The potential N mineralization obtained from aerobic incubation under controlled conditions of soil samples collected before sunflower sowing was higher for ENTEC than ASN or control treatments. A higher δ15N in the soil indicated larger non-exchangeable NH4+ fixation in soils from the plots treated with ENTEC or ASN-170 than from the ASN-130 or the control. These results open the opportunity to increase N efficiency by designing crop rotations able to profit from the effect of NI on the soil residual N

Una estimación de las primas de riesgo por inflación en el caso español

En este trabajo se estiman primas por inflacion, a partir de su forma funcional teorica en el marco del CCAPM: el producto entre el coeficiente de aversion relativa al riesgo y la covarianza condicional entre consumo y precios. Esta ultima se ha estimado a partir de un modelo GARCH bivariante para las series trimestrales de consumo y precios durante el periodo 1970Ö1995. El coeficiente de aversion al riesgo se ha fijado a partir de las estimaciones disponibles para el caso español. Los resultados muestran que las primas por inflacion a los plazos de 1, 3, y 5 años han sido notablemente reducidas (por debajo de 40 puntos basico) y estables. La evidencia es, pues, favorable a la verificacion, en el caso español, de la relacion de Fisher, segun la cual el tipo de interes nominal es la suma del tipo de interes exÖante y de la tasa esperada de inflacion. Contiene graficos y bibliografia. (fas) (jah) (mac

Quantitative characterization of five cover crop species

The introduction of cover crops in the intercrop period may provide a broad range of ecosystem services derived from the multiple functions they can perform, such as erosion control, recycling of nutrients or forage source. However, the achievement of these services in a particular agrosystem is not always required at the same time or to the same degree. Thus, species selection and definition of targeted objectives is critical when growing cover crops. The goal of the current work was to describe the traits that determine the suitability of five species (barley, rye, triticale, mustard and vetch) for cover cropping. A field trial was established during two seasons (October to April) in Madrid (central Spain). Ground cover and biomass were monitored at regular intervals during each growing season. A Gompertz model characterized ground cover until the decay observed after frosts, while biomass was fitted to Gompertz, logistic and linear-exponential equations. At the end of the experiment, carbon (C), nitrogen (N), and fibre (neutral detergent, acid and lignin) contents, and the N fixed by the legume were determined. The grasses reached the highest ground cover (83–99%) and biomass (1226–1928 g/m2) at the end of the experiment. With the highest C:N ratio (27–39) and dietary fibre (527–600 mg/g) and the lowest residue quality (~680 mg/g), grasses were suitable for erosion control, catch crop and fodder. The vetch presented the lowest N uptake (2·4 and 0·7 g N/m2) due to N fixation (9·8 and 1·6 g N/m2) and low biomass accumulation. The mustard presented high N uptake in the warm year and could act as a catch crop, but low fodder capability in both years. The thermal time before reaching 30% ground cover was a good indicator of early coverage species. Variable quantification allowed finding variability among the species and provided information for further decisions involving cover crop selection and management

Arsenic distribution in a pasture area impacted by past mining activities

[EN]Former mine exploitations entail a serious threat to surrounding ecosystems as after closure of mining activities their unmanaged wastes can be a continuous source of toxic trace elements. Quite often these mine sites are found within agricultural farming areas, involving serious hazards as regards product (feed/food) quality. In this work a grazing land impacted by the abandoned mine exploitation of an arsenical deposit was studied so as to evaluate the fate of arsenic (As) and other trace elements and the potential risks involved. With this aim, profile soil samples (0–50 cm) and pasture plant species (Agrostis truncatula, Holcus annus and Leontodon longirostris) were collected at different distances (0–100 m) from the mine waste dump and analyzed for their trace element content and distribution. Likewise, plant trace element accumulation from impacted grazing soils and plant trace element translocation were assessed. The exposure of livestock grazing animals to As was also evaluated, establishing its acceptability regarding food safety and animal health. International soil guideline values for As in grazing land soils (50 mg kg−1) resulted greatly exceeded (up to about 20-fold) in the studied mining-affected soils. Moreover, As showed a high mobilization potential under circumstances such as phosphate application or establishment of reducing conditions. Arsenic exhibited relatively high translocation factor (TF) values (up to 0.32–0.89) in pasture plant species, reaching unsafe concentrations in their above-ground tissues (up to 32.9, 16.9 and 9.0 mg kg−1 in Agrostis truncatula, Leontodon longirostris and Holcus annus, respectively). Such concentrations represent an elevated risk of As transfer to the high trophic-chain levels as established by international legislation. The limited fraction of arsenite found in plant roots should play an important role in the relatively high As root-to-shoot translocation shown by these plant species. Both soil ingestion and pasture intake resulted important entrance pathways of As into livestock animals, showing quite close contribution levels. The cow acceptable daily intake (ADI) of As regarding food safety was surpassed in some locations of the study area when the species Agrostis truncatula was considered as the only pasture feed. Restrictions in the grazing use of lands with considerable As contents where this plant was the predominant pasture species should be established in order to preserve food quality. Therefore, the exposure of livestock animals to As via both soil ingestion and pasture consumption should be taken into account to establish the suitability of mining-impacted areas for gazing

On modelling planning under uncertainty in manufacturing

We present a modelling framework for two-stage and multi-stage mixed 0-1 problems under uncertainty for strategic Supply Chain Management, tactical production planning and operations assignment and scheduling. A scenario tree based scheme is used to represent the uncertainty. We present the Deterministic Equivalent Model of the stochastic mixed 0-1 programs with complete recourse that we study. The constraints are modelled by compact and splitting variable representations via scenarios