Search results for "Geta"
showing 10 items of 3789 documents
Protocolo de propagación de helechos
2015
En el Jardín Botánico de la Universitat de València estudiamos protocolos específicos para diversas especies. Este artículo pretende dar unas pautas básicas para propagar los helechos en general, utilizando materiales fácilmente accesibles y sin un instrumental especifico.
Automatic analyzis of droplet impact by high speed imaging
2012
International audience; The impact of agricultural activities on the water quality is the consequence of the loss of fertilisers (chemical fertilisers, livestock effluent, also referred to as farm fertiliser, food-processing effluent and sludge) and crop treatment products (phytosanitary products). This pollution may prevent certain uses of water, notably its use for human and animal food (groundwater and surface water), and leads to a deterioration in aquatic environments. In the domain of vineyard precision spraying research, one of the most important objectives is to minimize the volume of phytosanitary products. It is also to be more environmentally respectful with more effective vine l…
Modeling the hydrological and mechanical effect of roots in shallow landslide analysis
2015
The additional cohesion exercised by vegetation roots (cr) provides an important contribution to the slope stability. This study proposes a methodology for estimating the cr term in a hillslope landslide analysis within a coupled ecohydrological-stability model. The coupled model simulates the spatial distribution and temporal dynamics of the Factor of Safety (FS) as a function of soil moisture dynamics, by taking into account the hydrological effects of vegetation through the root water uptaking. The additional mechanical root cohesion is estimated in a Fiber Bundle Model framework that allows for the evaluation of the root strength as a function of stress-strain relationships of populatio…
Hydrological and mechanical effects of roots in shallow landslide analysis: A physically-based approach
2015
This study provides the first insights of a methodology for estimating the additional cohesion exercised by vegetation roots in a hillslope landslide analysis within a coupled ecohydrological-stability model. The existing coupled system is able to simulate the spatial distribution and temporal dynamics of Factor of Safety (FS) as a function of soil moisture dynamics. The model takes into account the hydrological effects of vegetation which, through the root water uptaking, contributes in reducing the soil water content and, thus, in increasing the slope stability. The additional mechanical root cohesion is estimated in a Fiber Bundle Model (FBM) framework that allows for the evaluation of t…
El parasitismo en la obra de José Eugenio Olavide : dermatología general y clínica iconográfica de enfermedades de la piel o dermatosis (1871)
1985
En el siglo XIX, la idea de un pathsito vegetal como origen de alguna enfermedad comenzó a cristalizar en torno a la década dé los 30. Su inicio puede fijarse en los trabajos que sobre la muscardina del gusano de seda realizó Agostino Bassi, quien descubrió que dicha enfermedad era causada por un hongo parà.sito. Este hecho le llevo a formular la teoría del origen parasitario de las enfermedades infecciosas. Desde entonces, y hasta los arios 50, se aceptó la etiología fúngica de algunas enfermedades, pero no la teoría de los gérmenes como causa del resto de las enfermedades infecciosas.
Patrones estructurales y funcionales de las comunidades de procariotas en humedales mediterráneos y su relación con el ciclo del carbono
2023
Las zonas húmedas mediterráneas juegan un papel muy importante en los ciclos biogeoquímicos, ya que la presencia de agua, de forma constante o transitoria, favorece unas altas tasas metabólicas. Respecto al ciclo del carbono, los humedales mediterráneos se ven activamente involucrados en la captación o en la emisión de gases de efecto invernadero carbonados (C-GEI) hacia la atmósfera, concretamente el dióxido de carbono y el metano. Esta relevancia de los humedales en el ciclo del carbono se debe, en parte, a la actividad de las comunidades de procariotas que habitan en el agua y en el sedimento de las zonas húmedas, puesto que la abundancia y versatilidad metabólica de los procariotas les …
Short-term effects of potassium fertilization on the hydraulic conductance of Laurus nobilis L.
2011
This study reports experimental evidence on the effect of short term potassium fertilization on potassium uptake, tissue concentration and hydraulic conductance of pot-grown laurel plants. Potassium uptake and loading into the xylem of laurel seedlings increased within 24 h from fertilization. Potassium was not accumulated in roots and leaves, but the [K+] of xylem sap was 80% higher in fertilized plants (+K) than in potassium starved plants (-K), likely as a result of recirculation between xylem and phloem. This increase in xylem sap [K+] resulted in a 45% increase in transpiration rate, a 30% increase in plant hydraulic conductance (Kplant) and a 120% increase in leaf specific conductivit…
Hydrophytic vegetation aspects in the Nebrodi mountains (Sicily)
2009
The vegetation of damp areas in the Nebrodi Natural Park was already surveyed in some studies (Brullo et al. 1994). In particular, the various hygro and hydrophytic aspects were referred to associations belonging to the Phragmitetea and the Potamogetonetea classes respectively. Small lacustrine habitats in Sicily have disappeared almost everywhere and are conserved still today only in the Nebrodi Mountains. They host widely distributed hydrophytes. Some of these plants are rather localized in Sicily, e.g. Potamogeton polygonifolius Pourr. and Utricularia australis R. Br. The latter occurs also in the Madonie Mountains. Recent analyses revealed some hollows characterized by an accentuated re…
Pattern formation in hyperbolic reaction-transport systems and applications to dryland ecology
2023
Pattern formation and modulation is an active branch of mathematics, not only from the perspective of fundamental theory but also for its huge applications in many fields of physics, ecology, chemistry, biology, and other sciences. In this thesis, the occurrence of Turing and wave instabilities, giving rise to stationary and oscillatory patterns, respectively, is theoretically investigated by means of two-compartment reaction-transport hyperbolic systems. The goal is to elucidate the role of inertial times, which are introduced in hyperbolic models to account for the finite-time propagation of disturbances, in stationary and transient dynamics, in supercritical and subcritical regimes. In p…
The classification of submerged vegetation using hyperspectral MIVIS data
2009
The aim of this research is to use hyperspectral MIVIS data to map the Posidonia oceanica prairies in a coastal lagoon (Stagnone di Marsala). It is approximately 12 km long and 2 km wide and is linked to the open sea by two shallow openings. This environment is characterised by prairies of phanerogams, the most common of which is Posidonia oceanica, an ideal habitat for numerous species of fish, molluscs and crustaceans. A knowledge of the distribution of submerged vegetation is useful to monitor the health of the lagoon. In order to classify the MIVIS imagery, the attenuation effects of the water column have been removed from the signal using Lyzenga’s technique. A comparison between class…