Evaluation of optical techniques for characterising soil organic matter quality in agricultural soils

Soil organic matter (SOM) is one of the main global carbon pools. It is a measure of soil quality as its presence increases carbon sequestration and improves physical and chemical soil properties. The determination and characterisation of humic substances gives essential information of the maturity and stresses of soils as well as of their health. However, the determination of the exact nature and molecular structure of these substances has been proven difficult. Several complex techniques exist to characterise SOM and mineralisation and humification processes. One of the more widely accepted for its accuracy is nuclear magnetic resonance (NMR) spectroscopy. Despite its efficacy, NMR needs significant economic resources, equipment, material and time. Proxy measures like the fluorescence index (FI), cold and hot-water extractable carbon (CWC and HWC) and SUVA-254 have the potential to characterise SOM and, in combination, provide qualitative and quantitative data of SOM and its processes. Spanish and British agricultural cambisols were used to measure SOM quality and determine whether similarities were found between optical techniques and 1H NMR results in these two regions with contrasting climatic conditions. High correlations (p < 0.001) were found between the specific aromatic fraction measured with 1H NMR and SUVA-254 (Rs = 0.95) and HWC (Rs = 0.90), which could be described using a linear model. A high correlation between FI and the aromatics fraction measured with 1H NMR (Rs = −0.976) was also observed. In view of our results, optical measures have a potential, in combination, to predict the aromatic fraction of SOM without the need of expensive and time consuming techniques

Liquid-gas separation in colloidal electrolytes

The liquid-gas transition of an electroneutral mixture of oppositely charged colloids, studied by Monte Carlo simulations, is found in the low-temperature–low-density region. The critical temperature shows a nonmonotonous behavior as a function of the interaction range, −1, with a maximum at 10, implying an island of coexistence in the - plane. The system is arranged in such a way that each particle is surrounded by shells of particles with alternating charge. In contrast with the electrolyte primitive model, both neutral and charged clusters are obtained in the vapor phase

Relativistically extended Blanchard recurrence relation for hydrogenic matrix elements

General recurrence relations for arbitrary non-diagonal, radial hydrogenic matrix elements are derived in Dirac relativistic quantum mechanics. Our approach is based on a generalization of the second hypervirial method previously employed in the non-relativistic Schr\"odinger case. A relativistic version of the Pasternack-Sternheimer relation is thence obtained in the diagonal (i.e. total angular momentum and parity the same) case, from such relation an expression for the relativistic virial theorem is deduced. To contribute to the utility of the relations, explicit expressions for the radial matrix elements of functions of the form $r^\lambda$ and $\beta r^\lambda$ ---where $\beta$ is a Dirac matrix--- are presented.Comment: 21 pages, to be published in J. Phys. B: At. Mol. Opt. Phys. in Apri

Exterior Differential System for Cosmological G2 Perfect Fluids and Geodesic Completeness

In this paper a new formalism based on exterior differential systems is derived for perfect-fluid spacetimes endowed with an abelian orthogonally transitive G2 group of motions acting on spacelike surfaces. This formulation allows simplifications of Einstein equations and it can be applied for different purposes. As an example a singularity-free metric is rederived in this framework. A sufficient condition for a diagonal metric to be geodesically complete is also provided.Comment: 27 pages, 0 figures, LaTeX2e, to be published in Classical and Quantum Gravit

Hypoxia conditions differentially modulate normal and osteoarthritic chondrocyte proteomes

Comunicaciones a congreso

Análisis de las conductas de los entrenadores después del tiro en baloncesto

La presente investigación analiza las conductas de los entrenadores de baloncesto después del lanzamiento a canasta (tanto de los jugadores de su equipo como del equipo contrario) en situaciones de competición en categorías de formación. Intervinieron en el presente estudio tres entrenadores, todos poseen la titulación española oficial necesaria para entrenar enlas diferentes categorías. Se han analizado 9 partidos oficiales de la Liga Gallega (3 por cada uno de los 3 entrenadores participantes) y se registraron 1196 conductas tras lanzamiento. El instrumento utilizado para la recogida de datos procede de una adaptación del Coach Behavioral Assessment System (Smith, Smoll y Hunt, 1977; Cruz, 1989) y del Sistema de Observación de las Conductas del Entrenador (Montero, 2004). Tras los resultados obtenidos,se puede afirmar que las conductas de inhibición (“ignorar el error” y “no reforzar”) son las más frecuentes y que el resultado en el marcador está asociado a cambios en el comportamiento de los entrenadores

Occupational exposure to endocrine-disrupting chemicals and other parental risk factors in hypospadias and cryptorchidism development: a case–control study

Aim of the study: Endocrine-disrupting chemicals (EDCs) are exogenous agents that are capable of altering the endocrine system functions, including the regulation of developmental processes. The aim of this study was to investigate the association between EDC exposure and other parental factors in the etiology of hypospadias and cryptorchidism. Methods: A case–control study was conducted. Cases (n = 210) were infants aged between 6 months and 14 years diagnosed with hypospadias or cryptorchidism who attended the authors' hospital over a period of 18 months, and controls (n = 210) were infants within the same range of age and without any urological disorders who attended the outpatient clinic of the same hospital during the same time period. Their selection was independent of exposures. Data on parental occupational exposure to EDCs and other sociodemographic variables were collected through face-to-face interviews and systematically for both cases and controls. Crude and adjusted odds ratios (ORs) were estimated to control for confounding with their 95% confidence interval (CI) by means of logistic regressions. Specifically, three final models of a dichotomous outcome were constructed: one for cryptorchidism, one for hypospadias, and the third considering both malformations together. The Hosmer-Lemeshow test was used to assess the goodness of fit of the models. Their discriminatory accuracy (DA) was ascertained by estimating their areas under the receiver operating characteristic curves area under the curve (AUC) along with their 95% CI. Results: Associations were found between advanced maternal age (OR adjusted = 1.82; 95% CI: 1.14–2.92), mother's consumption of anti-abortives (OR = 5.40; 95% CI: 1.40–38.5) and other drugs (OR = 2.02; 95% CI: 1.31–3.16) during pregnancy, maternal and paternal occupational exposure to EDCs (OR = 4.08; 95% CI: 2.03–8.96 and OR = 3.90; 95% CI: 2.41–6.48, respectively), fathers smoking (OR = 2.0; 95% CI: 1.33–2.99), and fathers with urological disorders (OR = 2.31; 95% CI: 1.15–4.90). Maternal and paternal high educational level could be protective of cryptorchidism (OR = 0.47; 95% CI: 0.28–0.76 and OR = 0.63; 95% CI: 0.42–0.93, respectively). The DA of the models for the whole sample (AUC = 0.75; 95% CI: 0.70–0.79) for cryptorchidism (AUC = 0.76; 95% CI: 0.71–0.82) and for hypospadias (AUC = 0.75; 95% CI: 0.69–0.81) was moderately high. Conclusions: Advanced age, some parental occupational exposure to EDCs, some drug consumption, smoking, and the father's history of urological disorders may increase risk and predict the developments of these malformations. Studies with higher samples sizes are needed to assess associations between individual EDC occupational exposures and drugs and these malformations. [Table presented