Un método sencillo para la estimación de la porosidad de un agregado de suelo

4 Pags.- 2 Figs. Trabajo originalmente presentado en las XII Jornadas de Investigación en la Zona No Saturada del Suelo (Alcalá de Henares, 18-20 de nov. de 2015). © de los textos: sus autores[ES] Este trabajo presenta un nuevo método (AM) para estimar la porosidad de agregados de suelo, , expresada como el cociente entre el volumen interno de poros (Vi) y el volumen externo del agregado (VT). VT se calcula a partir de la densidad de partícula, el peso del agregado y el Vi, estimado este último a partir del peso del agregado saturado en alcohol. El método se validó comparando VT por AM con el VT medido por fotogrametría (PHM), sobre 36 agregados de 8-16 mm procedentes de un suelo bajo laboreo tradicional (CT), reducido (RT) y no laboreo (NT). Los resultados muestran una buena relación entre el VT medido con PHM y AM (y = 0,94 x + 0,01; R2 = 0,99). El método fue suficientemente sensible para detectar diferencias entre los sistemas de laboreo. Los agregados de suelo bajo NT y RT presentaron una significativamente mayor que bajo CT.[EN] This work presents a new method (AM) to estimate the soil aggregate porosity, , expressed as the quotient between the internal pore volume (Vi) and the aggregate volume (VT). VT is calculated from the particle soil density, and the aggregate weight and Vi, the last one estimated form the weight of the ethanol-saturated agregate. The method was validated by comparing the VT estimated with AM with the corresponding value estimated by the photogrammetry technique (PHM), on 36 aggregates of 8- 16 mm size collected from conventional tillage (CT), reduced tillage (RT) and no tillage (NT). Results show a good relationship between VT measured with PHM and with AM (y = 0.94 x + 0.01, R2 = 0.99). The values were significantly higher in soil aggregates under NT and RT than those under CT.Este trabajo ha sido financiado por el Ministerio de Economía y Competitividad de España (AGL2010-22050-C03-02).Peer reviewe

«Diáspora trans», fronteras corporeizadas y tránsito(s) migratorio(s) en México

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Filosofía y Letras, Instituto Universitario de Estudios de la Mujer. Fecha de lectura: 29-11-2019Esta tesis tiene embargado el acceso al texto completo hasta el 29-05-2021La tesis doctoral aquí expuesta es, sobre todo, un trabajo de traducción, un ejercicio etnográfico de interpretación entre diferentes universos simbólicos que reniega de la aspiración a lo universal y parte necesariamente de un enfoque reflexivo que rehúye caer en la apropiación y reproducción de categorías dadas, e indaga sobre epistemologías y marcos de entendimiento alternativos que necesariamente apuesten por la hibridez y el «descentramiento» de los géneros-sexos y sexualidades. Las siguientes páginas invitan a reflexionar sobre las formas diversas en que interfieren los múltiples contextos migratorios en las experiencias subjetivas de la diáspora trans en movimiento, proveniente de las regiones del Triángulo Norte de América Central, fundamentalmente Honduras, y con menos frecuencia, El Salvador y Guatemala, en su tránsito por México hacia ese «otro lado» imaginado. La diáspora trans se proyecta como «identidades» híbridas, fluidas y contextuales que transita simultáneamente los géneros disponibles en función del territorio en el que participen y de la audiencia que tengan delante. Así, se construye y se actualiza a través de la identificación, reiteración y transgresión de las diferentes fronteras articuladas de sexo, de género, de clase, de raza, de etnia, de edad, de estatus migratorio, etc. Fronteras que serán (re)significadas en los diferentes procesos de tránsito, desquiciando cuestiones de pertenencia y representación de género y proporcionarán nuevas posibilidades en este vaivén transgresor de significados, relaciones de poder y estructuras, siempre mediado por la mirada de «lxs Otrxs». De esta forma, estas transgresiones subjetivas de la diáspora trans en movimiento interferirán en sus devenires migratorios y en sus formas de imaginar el hogar, muy arraigadas en la libertad, el respeto y la legitimidad de sus expresiones corporizadas de géner

Relación entre la madurez vocacional y la motivación hacia el aprendizaje académico

Currently, the demands, responsibilities and obligations to enter the workforce are greater and the vocational decision-making process becomes increasingly difficult, therefore, it is necessary to encourage schools to seek guidance strategies that facilitate tools and a adequate advice to students.Vocational Maturity is defined as the degree to which a person adopts a decision based on the knowledge of their academic and professional alternatives, after analyzing their values, goals, interests, abilities and personal and social conditioning factors (Lucas and Carbonero, 2003).There are many motivational dimensions that influence academic commitment and that must be taken into account in order to influence student academic performance (Rodríguez, 2009). From this study, it is considered that one of these variables is vocational maturity and therefore, the objective is to know if there is a relationship between Vocational Maturity and the motivation towards learning in a total sample of 1540 subjects belonging to 27 Centers Educational Secondary Education of the provinces of Badajoz and Cáceres, with ages between 15 and 19 years.The methodology used in this study is descriptive through a quantitative paradigm by means of two survey-type instruments: to measure the Motivation towards Learning, the MAPE I questionnaire was used by the authors Jesús Alonso Tapia and Javier Sánchez Ferrer (1992 ), and for the measurement of the Vocational Maturity the CMV questionnaire adapted from Rosa (2015) was used.The results obtained show that there is a relationship between both variables for the three dimensions studied in the Motivation towards Learning.Actualmente, las exigencias, responsabilidades y obligaciones para incorporarse al mundo laboral son mayores y el proceso de toma de decisiones vocacional se torna cada vez más difícil, por ello, resulta necesario animar a los centros educativos a buscar estrategias de orientación que faciliten herramientas y un asesoramiento adecuado al alumnado.La Madurez Vocacional se define como el grado en que una persona adopta una decisión basada en el conocimiento de sus alternativas académicas y profesionales, previo análisis de sus valores, metas, intereses, habilidades y condicionantes personales y sociales (Lucas y Carbonero, 2003).Son muchas las dimensiones motivacionales que influyen en el compromiso académico y que deben tenerse en cuenta para incidir sobre el rendimiento académico del alumnado (Rodríguez, 2009). Desde este estudio, se considera que una de estas variables es la madurez vocacional y por ello, el objetivo que se plantea es conocer si existe relación entre la Madurez Vocacional y la motivación hacia el aprendizaje en una muestra total de 1540 sujetos pertenecientes a 27 Centros Educativos de Educación Secundaria de las provincias de Badajoz y Cáceres, con edades comprendidas entre 15 y 19 años.La metodología utilizada en este estudio es de corte descriptivo a través de un paradigma cuantitativo mediante dos instrumentos de tipo encuesta: para la medida de la Motivación hacia el Aprendizaje se utilizó el cuestionario MAPE I de los autores Jesús Alonso Tapia y Javier Sánchez Ferrer (1992), y para la medida de la Madurez Vocacional se utilizó el cuestionario CMV adaptado de Rosa (2015).Los resultados obtenidos muestran que si existe relación entre ambas variables para las tres dimensiones que se estudian en la Motivación hacia el Aprendizaje

Effects of tillage on the soil water retention curve during a fallow period of a semiarid dryland

31 Pags.- 2 Tabls.- 7 Figs. The definitive version is available at: http://www.publish.csiro.au/srTillage practices have a significant influence on the soil hydro-physical properties. The objective of this work was to evaluate the effect of tillage on the α (a scaling factor) and n (a pore size distribution parameter) van Genuchten soil water retention curve parameters during an 18-month long fallow period in a semiarid dryland. Three different tillage systems employed during 23 years of trials were compared: conventional (CT), reduced (RT) and no-tillage (NT). Measurements of soil bulk density (ρb) and the soil water retention curve θ(ψ) were performed at 0–10, 10–20 and 20–30 cm soil depths. The θ(ψ) was determined with the Time Domain Reflectometry (TDR)-pressure cells at the following pressure heads: 0.5, 1.5, 3, 10, 50, 100, 500 and 1500 kPa. From these data, α, n and the SDexter index were evaluated. The 0–40 cm depth soil volumetric water content, θ, was also measured in the field using the TDR technique. Compared with CT and RT, NT had the highest θ values during all the fallow period. No significant influence of soil depth on θ(ψ) was observed in all tillage treatments at each sampling date. Although under consolidated soil conditions no significant differences in ρb and the water content at saturation (θs) were observed among tillage treatments, NT had the highest and lowest values of ρb and θs, respectively. The loosening of soil due to tillage practices in CT and RT significantly decreased ρb and increased θ at the wet-end section of θ(ψ). Post-tillage rainfall resulted in significant decreases in θs, α and the maximum value of the pore size distribution (PSDmax). The different soil structure created by mouldboard ploughing (CT) and chiselling (RT) explained the higher PSDmax under RT than CT. The most important changes in θ(ψ) followed the first copious effective rainfall events (>10 mm) after tillage. These facts enabled the soil to recover the pre-tillage water retention curve shapes and the van Genuchten parameters pre-tillage values. Effective rainfall events in the late fallow had a minor effect on the water retention curve. Although tillage tended to increase n, this change was not significant. The SDexter index, which was also affected by tillage, was greater than 0.035 during all the fallow period, indicating good soil physical quality.Peer reviewe

A TDR-pressure cell design for measuring the soil water retention curve

The final version of this article is available at: http://www.sciencedirect.com/science/journal/01671987This paper presents a new type of pressure cell associated with a zigzag-shaped time domain reflectometry (TDR) probe for determining the soil-water retention (θ(ψ)) curve of disturbed thin soil samples. The pressure cell, designed for pressures ranging between 0 and −500 kPa, consisted of a zigzag copper rod (150-mm long, 2 mm in diameter) vertically installed in a clear plastic cylinder (60-mm high, 50 mm in internal diameter) with six vertical copper rods (60-mm long, 2 mm in diameter) arranged around the inner wall of the plastic cylinder. The cylinder was closed at the base with a nylon cloth and placed on a porous ceramic disc. The inner rod and the six-rod grille of the cell were connected respectively to the inner and outer conductors of a coaxial cable. The results showed that the correlation between the apparent dielectric constant measured with a standard three-rod TDR probe and the zigzag-shaped TDR probe, both immersed in five different non-conductive fluids, was excellent (R2 = 0.99). On the other hand, the volumetric water content measured with the TDR probe of the pressure cell filled up with sand, 2-mm sieved loam and clay-loam soils was highly correlated to the corresponding values calculated from the gravimetric water content and the soil bulk density (R2 = 0.97; RMSE = 2.32 × 10−2). The parameters of the θ(ψ) curves measured for these three different soils with the TDR-pressure cell were within the range of values found in the literature. The cell was also used to study the θ(ψ) changes of a 2–4-mm sample of loam soil aggregates after a slow and a fast-wetting process. While negligible changes in both the soil structure and θ(ψ) were observed following slow wetting, fast wetting resulted in disintegration of aggregates and drastic changes in the shape of the θ(ψ) curve.This research was supported by the Comisión Interministerial de Ciencia y Tecnología of Spain (grants AGL2004-07763-C02-02 and AGL2007-66320-CO2-02/AGR) and the European Union (FEDER funds).Peer reviewe

Low-cost materials to face soil and water pollution

In this mini-review, the authors comment on selected papers focused on the use of low-cost materials to prevent/remediate environmental pollution (specifically, soil and water pollution). The authors have selected publications corresponding to the years 2021 and 2022, using the searching tools Scopus, Web of Sciences, and Google Scholar to find basic data about the papers, the countries where the researches were carried out, number of citations, and other details indicative of the relevance of the works. Overall, the field of research is receiving growing attention and efforts, providing useful data on classical and new low-cost materials, both raw and modified by means of low-cost procedures, which constitute a clearly interesting alternative to face environmental pollution currently and for the futureS

Lactococcus garvieae: a small bacteria and a big data world

OBJECTIVE: To describe the importance of bioinformatics tools to analyze the big data yielded from new "omics" generation-methods, with the aim of unraveling the biology of the pathogen bacteria Lactococcus garvieae. METHODS: The paper provides the vision of the large volume of data generated from genome sequences, gene expression profiles by microarrays and other experimental methods that require biomedical informatics methods for management and analysis. RESULTS: The use of biomedical informatics methods improves the analysis of big data in order to obtain a comprehensive characterization and understanding of the biology of pathogenic organisms, such as L. garvieae. CONCLUSIONS: The "Big Data" concepts of high volume, veracity and variety are nowadays part of the research in microbiology associated with the use of multiple methods in the "omic" era. The use of biomedical informatics methods is a requisite necessary to improve the analysis of these data

Development of a New Method for the Determination of Manganese, Cadmium, Mercury and Lead in Whole Blood and Amniotic Fluid by Inductively Coupled Plasma Mass Spectrometry

Environmental exposure to metals among women, revealed their adverse effects on pregnancy. During this stage, blood levels of some metals increase so research on heavy metals transference from the mother’s blood to the developing foetus is of special interest and much attention has been paid to this matter. The amniotic fluid can be considered as a valuable marker of this prenatal exposure to exogenous factors. The aim of this study was to develop a method for the simultaneous determination of Mn, Cd, Hg, and Pb in whole maternal blood and amniotic fluid by ICP-MS. Strategies were given to minimise memory effects related to mercury and two widespread digestion procedures (open-vessel and microwave-assisted) were compared. Several quality controls, such as methodological and reagent blanks, spiked samples and duplicates were used to test the goodness of the developed method. Once optimised, the method was applied for the monitoring of Mn, Cd, Hg and Pb in 15 maternal blood and amniotic fluid samples obtained at delivery after informed consent. This study establishes that heavy metals pass into and accumulate in amniotic fluid and maternal blood. Thus, mean concentrations of Mn were similar in the two biological fluids studied, 21.6 ng/mL in maternal blood and 20.5 ng/mL in amniotic fluid. Mean Cd and mercury levels in blood and amniotic fluid were 1.3 and 6.3 ng/mL and 3.4 and 3.8 ng/mL, respectively. Concentrations of Pb were 16.4 ng/mL in blood and 13.7 ng/mL in amniotic fluid. Further studies are needed to evaluate the long-term health effects derived from this exposure.Plan Propio of the University of SevilleFundación Farmacéutica Avenzoa