Fungal microbiota from rain water and pathogenicity of Fusarium species isolated from atmospheric dust and rainfall dust

In order to determine the presence of Fusarium spp. in atmospheric dust and rainfall dust, samples were collected during September 2007, and July, August, and October 2008. The results reveal the prevalence of airborne Fusarium species coming from the atmosphere of the South East coast of Spain. Five different Fusarium species were isolated from the settling dust: Fusarium oxysporum, F. solani, F. equiseti, F. dimerum, and F. proliferatum. Moreover, rainwater samples were obtained during significant rainfall events in January and February 2009. Using the dilution-plate method, 12 fungal genera were identified from these rainwater samples. Specific analyses of the rainwater revealed the presence of three species of Fusarium: F. oxysporum, F. proliferatum and F. equiseti. A total of 57 isolates of Fusarium spp. obtained from both rainwater and atmospheric rainfall dust sampling were inoculated onto melon (Cucumis melo L.) cv. Piñonet and tomato (Lycopersicon esculentum Mill.) cv. San Pedro. These species were chosen because they are the main herbaceous crops in Almeria province. The results presented in this work indicate strongly that spores or propagules of Fusarium are able to cross the continental barrier carried by winds from the Sahara (Africa) to crop or coastal lands in Europe. Results show differences in the pathogenicity of the isolates tested. Both hosts showed root rot when inoculated with different species of Fusarium, although fresh weight measurements did not bring any information about the pathogenicity. The findings presented above are strong indications that long-distance transmission of Fusarium propagules may occur. Diseases caused by species of Fusarium are common in these areas. They were in the past, and are still today, a problem for greenhouses crops in Almería, and many species have been listed as pathogens on agricultural crops in this region. Saharan air masses dominate the Mediterranean regions. The evidence of long distance dispersal of Fusarium spp. by atmospheric dust and rainwater together with their proved pathogenicity must be taken into account in epidemiological studies.

FMECA application to Rainfall Hazard prevention

This paper presents a System Safety application to reduce the economical impact hazards in growings produced by Rainfall. System Safety is an engineering subdiscipline oriented to identify and mitigate the possible hazards to a system under study. Inside the System Safety area, the FMECA (Failure Mode, Effects and Criticallity Analysis) is a popular tool to analyze and identify the failures and weaknesses points of any system. Basically, it consist on identifying systematically the failure modes of a system to mitigate them as much as possible. The idea is to study three different kind of growings (stone fruits in the south of Spain, wheat production in Castilla Leon and Olive trees production in Andalucia) using this methodology in order to identify all the hazardous situations produced by rainfall. Applying the state of the art weather forecast techniques, this information would help farmers to prevent and mitigate the identified hazardous situations. The aim of the work is to prevent the economical hazards as are defined in the System Safety area: "Any real or potential condition that can cause injury, illness, or death to personnel; damage to or loss of a system, equipment or property; or damage to the environment", so the study is not reduced to the analysis of catastrophical situations but aboutany kind of economical damage produced by rainfall.

LHPP, the light-harvesting NADPH:protochlorophyllide (Pchlide) oxido¬reductase:Pchlide complex of etiolated plants, is developmentally expressed across the barley leaf gradient

NADPH:protochlorophyllide oxidoreductase is a key enzyme for the light-induced greening of etiolated angiosperm plants. In barley, two POR proteins exist termed PORA and PORB that have previously been proposed to structurally and functionally cooperate in terms of a higher molecular mass light-harvesting complex named LHPP, in the prolamellar body of etioplasts [Nature 397 (1999) 80]. In this study we examined the expression pattern of LHPP during seedling etiolation and de-etiolation under different experimental conditions. Our results show that LHPP is developmentally expressed across the barley leaf gradient. We further provide evidence that LHPP operates both in plants that etiolate completely before being exposed to white light and in plants that etiolate only partially and begin light-harvesting as soon as traces of light become available in the uppermost parts of the soil. As a result of light absorption, in either case LHPP converts Pchlide a to chlorophyllide (Chlide) a and in turn disintegrates. The released Chlide a, as well as Chlide b produced upon LHPP’s light-dependent dissociation, which leads to the activation of the PORA as a Pchlide b-reducing enzyme, then bind to homologs of water-soluble chlorophyll proteins of Brassicaceae. We propose that these proteins transfer Chlide a and Chlide b to the thylakoids, where their esterification with phytol and assembly into the photosynthetic membrane complexes ultimately takes place. Presumably due to the tight coupling of LHPP synthesis and degradation, as well as WSCP formation and photosynthetic membrane assembly, efficient photo-protection is conferred onto the plant.

Hybrid topological derivative and gradient-based methods for electrical impedance tomography

We present a technique to reconstruct the electromagnetic properties of a medium or a set of objects buried inside it from boundary measurements when applying electric currents through a set of electrodes. The electromagnetic parameters may be recovered by means of a gradient method without a priori information on the background. The shape, location and size of objects, when present, are determined by a topological derivative-based iterative procedure. The combination of both strategies allows improved reconstructions of the objects and their properties, assuming a known background.

Diffusion Gradient Temporal Difference for Cooperative Reinforcement Learning with Linear Function Approximation

We introduce a diffusion-based algorithm in which multiple agents cooperate to predict a common and global statevalue function by sharing local estimates and local gradient information among neighbors. Our algorithm is a fully distributed implementation of the gradient temporal difference with linear function approximation, to make it applicable to multiagent settings. Simulations illustrate the benefit of cooperation in learning, as made possible by the proposed algorithm.

Design of spherical symmetric gradient index lenses

Spherical symmetric refractive index distributions also known as Gradient Index lenses such as the Maxwell-Fish-Eye (MFE), the Luneburg or the Eaton lenses have always played an important role in Optics. The recent development of the technique called Transformation Optics has renewed the interest in these gradient index lenses. For instance, Perfect Imaging within the Wave Optics framework has recently been proved using the MFE distribution. We review here the design problem of these lenses, classify them in two groups (Luneburg moveable-limits and fixed-limits type), and establish a new design techniques for each type of problem.

On the design of spherical gradient index lenses

Classical spherical gradient index (GRIN) lenses (such as Maxwell Fish Eye lens, Eaton lens, Luneburg lens, etc.) design procedure using the Abel integral equation is reviewed and reorganized. Each lens is fully defined by a function called the angle of flight which describes the ray deflection through the lens. The radial refractive index distribution is obtained by applying a linear integral transformation to the angle of flight. The interest of this formulation is in the linearity of the integral transformation which allows us to derive new solutions from linear combinations of known lenses. Beside the review of the classical GRIN designs, we present a numerical method for GRIN lenses defined by the Abel integral equation with fixed limits, which is an ill-posed problem.

Instabilities in two-liquid layers subject to a horizontal temperature gradient

We study theoretically the stability of two superposed fluid layers heated laterally. The fluids are supposed to be immiscible, the interface undeformable and of infinite horizontal extension. Combined thermocapillary and buoyancy forces give rise to a basic flow when a temperature difference is applied. The calculations are performed for a melt of GaAs under a layer of molten B2 O3 , a configuration of considerable technological importance. Four dif- ferent flow patterns and five temperature configurations are found for the basic state in this system. A linear stability analysis shows that the basic state may be destabilized by oscilla- tory motions leading to the so-called hydrothermal waves. Depending on the relative height of the two layers these hydrothermal waves propagate parallel or perpendicular to the temperature gradient. This analysis reveals that these perturbations can alter significantly the liquid flow in the liquid-encapsulated crystal growth techniques.

Effect of reservoir tillage on rainwater harvesting and soil erosion control under a developed rainfall simulator.

Soil erosion is a serious environmental threat in the Mediterranean region due to torrential rainfalls, and it contributes to the degradation of agricultural land. Techniques such as rainwater harvesting may improve soil water storage and increase agricultural productivity, which could result in more effective land usage. Reservoir tillage is an effective system of harvesting rainwater, but it has not been scientifically evaluated like other tillage systems. Its suitability for the conditions in Spain has not been determined. To investigate and quantify water storage from reservoir tillage and how it could be adapted to improve infiltration of harvested rainwater, a laboratory-scale rainfall simulator was developed. Rainfall characteristics, including rainfall intensity, spatial uniformity and raindrop size, confirm that natural rainfall conditions are simulated with sufficient accuracy. The simulator was auto-controlled by a solenoid valve and three pressure nozzles were used to spray water corresponding to five rainfall intensities ranging from 36 to 112 mm h-1 for 3 to 101-year return period with uniformity coefficients between 83 and 94%. In order to assess the reservoir tillage method under surface slopes of 0, 5, and 10%, three soil scooping devices with identical volume were used to make depressions in the following forms: a) truncated square pyramid, b) triangular prism, and c) truncated cone. These depressions were compared to a control soil surface with no depression. For the loam soil used in this study, results show that reservoir tillage was able to reduce soil erosion and surface runoff and significantly increase infiltration. There was significant difference between the depressions and the control. Compared to the control, depression (a) reduced surface runoff by about 61% and the sediment yield concentration by about 79%.

The application of inverse-dispersion and gradient methods to estimate ammonia emissions from a penguin colony.

Penguin colonies represent some of the most concentrated sources of ammonia emissions to the atmosphere in the world. The ammonia emitted into the atmosphere can have a large influence on the nitrogen cycling of ecosystems near the colonies. However, despite the ecological importance of the emissions, no measurements of ammonia emissions from penguin colonies have been made. The objective of this work was to determine the ammonia emission rate of a penguin colony using inverse-dispersion modelling and gradient methods. We measured meteorological variables and mean atmospheric concentrations of ammonia at seven locations near a colony of Adélie penguins in Antarctica to provide input data for inverse-dispersion modelling. Three different atmospheric dispersion models (ADMS, LADD and a Lagrangian stochastic model) were used to provide a robust emission estimate. The Lagrangian stochastic model was applied both in ‘forwards’ and ‘backwards’ mode to compare the difference between the two approaches. In addition, the aerodynamic gradient method was applied using vertical profiles of mean ammonia concentrations measured near the centre of the colony. The emission estimates derived from the simulations of the three dispersion models and the aerodynamic gradient method agreed quite well, giving a mean emission of 1.1 g ammonia per breeding pair per day (95% confidence interval: 0.4–2.5 g ammonia per breeding pair per day). This emission rate represents a volatilisation of 1.9% of the estimated nitrogen excretion of the penguins, which agrees well with that estimated from a temperature-dependent bioenergetics model. We found that, in this study, the Lagrangian stochastic model seemed to give more reliable emission estimates in ‘forwards’ mode than in ‘backwards’ mode due to the assumptions made.

A gradient-enhanced continuum damage model for fibre-reinforced materials

Modelo de daño no local definido a materiales fibrados. Este modelo se aplica al estudio de problemas típicos en la biomecánica de los tejidos blandos, como las paredes arteriales.

Summer rainfall variability in European Mediterranean mountains from the sixteenth to the twentieth century reconstructed from tree rings.

En este trabajo se utilizan dendrocronologías para reconstruir la precipitación estival.

Surveillance of habitats and plant diversity indicators across a regional gradient in the Iberian Peninsula

Dentro del Proyecto EBONE (Red de Observación de la Biodiversidad Europea) se analizan diferentes tipos de paisaje en varias zonas de Madrid y norte de Portugal. Se realiza un estudio de los habitats y la diversidad de especies con el objetivo principal de preservarlos y conservalos.

Grain size gradient length scale in ballistic properties optimization of functionally graded nanocrystalline steel plates

The last few years have highlighted the existence of two relevant length scales in the quest to ultrahigh-strength polycrystalline metals. Whereas the microstructural length scale – e.g. grain or twin size – has mainly be linked to the well-established Hall–Petch relationship, the sample length scale – e.g. nanopillar size – has also proven to be at least as relevant, especially in microscale structures. In this letter, a series of ballistic tests on functionally graded nanocrystalline plates are used as a basis for the justification of a “grain size gradient length scale” as an additional ballistic properties optimization parameter.

Cálculo de la recarga natural en grandes áreas, en función de la litología y la precipitación = Calculation of natural recharge in large areas, as a function of lithology and rainfall

En una región amplia como España se demuestra —mediante inferencias estadísticas sobre una muestra completa de 875 manantiales en los que se conoce su caudal medio y la litología de su área de alimentación y que han sido agrupados en regiones de distinta pluviometría— que la recarga media anual es una fracción fija de la precipitación media para cada litología. Se han establecido así unas tasas de recarga respecto de la precipitación para seis grupos litológicos de diferente permeabilidad: arenas, gravas y formaciones aluviales en general, 8.3%; conglomerados, 5.6%; areniscas, 7.3%; calizas y dolomías, 34.3%; margas, margocalizas, limos y arcillas, 3.3%; otras rocas, 1.3%. Teniendo en cuenta la representatividad de España, la cual tiene una gran variabilidad de litología, pluviometría, topografía, etcétera, estas tasas de recarga respecto de la precipita-ción son probablemente valores cuasi universales que pueden ser utilizados para estimar la recarga media o los recursos hídricos subterráneos medios de regiones amplias en cualquier parte del mundo, salvo en regiones especiales, como las que tienen permafrost, por ejemplo. En todo caso, estas tasas de recarga podrían ser retocadas para cada región según sus particulares características. Los datos de precipitación y litología son muy corrientes, por lo que el método puede ser ampliamente utilizado para completar balances hidráulicos.In a region as large as Spain, annual mean recharge is shown to be a fixed proportion of the mean rainfall for each lithology. This determination is based on statistical inferences from a complete sample of 875 springs for which mean flow and catchment areas are known and which have been grouped into distinct rainfall regions. Recharge rates have thus been established with respect to rainfall for six lithological groups with different permeability: sands, gravels and generally alluvial formations, 8.3%; conglomerates, 5.6%; sandstones, 7.3%; limestone and dolomite 34.3%; marls, marly limestones, silts and clays, 3.3%; and hard rocks, 1.3%. Considering the representativeness of Spain, which is large in size and has a highly varied lithology, topography and rainfall, these recharge rates for rainfall are probably quasi-universal values that can be used to estimate average recharge or average groundwater resources of large regions in any part of the world (except in special cases such as areas with permafrost, for example). For any case, these recharge rates can be adapted to each region according to its particular characteristics. Rainfall and lithology data are very common, and so the method can be widely used to calculate hydraulic balances.