Las operadoras del departamento de trafico de Teléfonos de México ante la tecnología digital

Desde 1969 la reconversión industrial es ya un hecho en el sistema de trabajo de las operadoras de tráfico de Teléfonos de México. Por ello, es imposible para la clase trabajadora de este sector impedir el avance tecnológico, pero lo que sí pueden hacer es luchar por obtener ventajas de interés colectivo como la reducción de la jornada de trabajo, la posibilidad de tener más capacitación para realizar labores de mayor relevancia como el mantenimiento del equipo, o bien, la instauración y atención de servicios de beneficio social como lo es la información especializada sobre becas, cursos, centros médicos y otros más

Response of wheat to additional nitrogen fertilizer application after pig slurry on over-fertilized soils

Pig slurry is a valuable nutrient resource but constitutes a waste disposal problem in areas of high animal density. In the semiarid area of Pla d’Urgell, in the Ebro Valley, North-East Spain, irrigated crops receive large amounts of nutrients in the form of manure and mineral fertilizers. We studied the effect of pig slurry and additional side-dress mineral fertilizers on irrigated wheat, Triticum aestivum L., on a coarse loam soil, with high soil P and K levels. Yields increased by 62.3% when using pig slurry. The application of ammonium sulfate nitrate sidedress did not significantly increase wheat production. The average apparent recoveries were higher for potassium (88.7%) than for nitrogen (51.3%) and phosphorus (36.3%). Greater amounts of soil NO3-N were measured over the four growing seasons, which was consistent with the amount of N applied. Macronutrient and micronutrient uptake was significant higher for pig slurry treatments, but only small differences were found between the pig slurry and pig slurry plus ammonium sulfate nitrate treatments. The unfertilized treatment showed significantly lower soil P, K, Cu and Zn content than pig slurry treatments; 34%, 21%, 34%, and 26% respectively. These findings could be used to develop a nutrient management plan based on knowledge of soil test results and crop nutrient removal. This could help to improve the use of pig slurry and mineral fertilizers on limited available land areas and prevent the accumulation of potentially toxic elements in soils and the export of nutrients through agricultural drainage

Job Stability and Gender Perspectives: Application of a Logistic Regression Model

Several changes have been taking place in the labour market since the 1970s that have created the right climate to spur organisations and workers to demand greater flexibility in employment. In this context, temporary employment has been the focus of many research papers and temporary contracts have been used as a tool to achieve labour flexibility. In order to understand the situation in Andalusia (Spain), this paper aims to identify the decisive factors in permanent employment. To this end, starting hypotheses will be defined about the decisive factors in permanent employment and the positive or negative significance of their influence; the starting hypotheses will then be tested empirically using a logistic regression model on a sample population of wage earners in Andalusia. In the second stage, given that the ratio of temporary contracts is much higher among women, the variable ‘gender’ is likely to be decisive in the construction of the regression model, therefore the decisive factors for permanent employment in Andalusia will be evaluated separately for men and women, in order to calibrate the impact of gender on job stability. Finally, based on the estimated probabilities of having a permanent job depending on gender, the degree of labour discrimination faced by women in the Andalusian labour market will be analysed

High-Resolution SMAP-Derived Root-Zone Soil Moisture Using an Exponential Filter Model Calibrated per Land Cover Type

Root-zone soil moisture (RZSM) plays a key role for most water and energy budgets, as it is particularly relevant in controlling plant transpiration and hydraulic redistribution. RZSM data is needed for a variety of different applications, such as forecasting crop yields, improving flood predictions and monitoring agricultural drought, among others. Remote sensing provides surface soil moisture (SSM) retrievals, whose key advantage is the large spatial coverage on a systematic basis. This study tests a simple method to retrieve RZSM estimates from high-resolution SSM derived from SMAP (Soil Moisture Active Passive). A recursive exponential filter using a time constant τ is calibrated per land cover type, which uses as an intermediate step a long-term ISBA-DIF (Interaction Soil Biosphere Atmosphere—Diffusion scheme) dataset over an area located in Catalonia, NE of Spain. The τ values thus obtained are then used as an input to the same recursive exponential filter, to derive 1 km resolution RZSM estimates from 1 km SMAP SSM, which are obtained from the original data by downscaling to a 1 km resolution, through the DISPATCH (DISaggregation based on a Physical and Theoretical scale CHange) methodology. The results are then validated with scaled in situ observations at different depths, over two different areas, one representative of rainfed crops, and the other of irrigated crops. In general, the estimates agree well with the observations over the rainfed crops, especially at a 10 cm and 25 cm depth. Nash–Sutcliffe (NS) scores ranging between 0.33 and 0.58, and between 0.37 and 0.56 have been found, respectively. Correlation coefficients for these depths are high, between 0.76 and 0.91 (10 cm), and between 0.71 and 0.90 (25 cm). For the irrigated sites, results are poorer (partly due to the extremely high heterogeneity present), with NS scores ranging between −2.57 and 0.16, and correlations ranging between −0.56 and 0.48 at 25 cm. Given the strong correlations and NS scores found in the surface, the sensitivity of the filter to different τ values was investigated. For the rainfed site, it was found, as expected, with increasing τ, increasing NS and correlations with the deeper layers, suggesting a better coupling. Nevertheless, a strong correlation with the surface (5 cm) or shallower depths (10 cm) observed over certain sites indicates a certain lack of skill of the filter to represent processes which occur at lower levels in the SM column. All in all, a calibration accounting for the vegetation was shown to be an adequate methodology in applying the recursive exponential filter to derive the RZSM estimates over large areas. Nevertheless, the relative shallow surface at which the estimates correlate in some cases seem to indicate that an effect of evapotranspiration in the profile is not well captured by the filter.This research was funded by the Torrres Quevedo program of the Spanish Science Ministry, MICINN (grant number PTQ-16-08766)

Momento Económico (40)

Temas de hoy, 2/ Hipótesis para la investigación sobre reconversión industrial, Ricardo Javier Martínez Atala, 3/ Reconversión automotriz y resistencia obrera en Volkswagen de México, Rogelio Palafox, Pedro Monroy y Yolanda Montiel, 6/ Estrategia del movimiento obrero ante la reconversión productiva, Socorro Fonseca Córdoba, 10/ Las operadoras del departamento de tráfico de Teléfonos de México ante la tecnología digital, Ma. Elena del Villar, 15