Search results for " LAG"
showing 10 items of 280 documents
Prediction of germination rates of weed species: Relationships between germination speed parameters and species traits
2011
International audience; In fields, the timing of weed emergence flushes is mostly related to the timing and rate of seed germination, which depend on seed dormancy level, soil temperature and water potential conditions as well as soil tillage and crop sowing date. Seed germination parameters are essential in weed dynamics models to account for the effects of soil conditions on weed demography. Since these parameters are difficult to measure, our objective was to test the possibility of estimating them from easily accessible information. Seed germination parameters (germination lag-time, time to mid-germination and mid-germination rate) were measured or collected from the literature for 25 w…
Planktonic stages of small pelagic fishes (Sardinella aurita and Engraulis encrasicolus) in the central Mediterranean Sea: The key role of physical f…
2018
Abstract Multidisciplinary studies are recently aiming to define diagnostic tools for fishery sustainability by coupling ichthyoplanktonic datasets, physical and bio-geochemical oceanographic measurements, and ocean modelling. The main goal of these efforts is to understand those processes that control the dispersion and fate of fish larvae and eggs, and thus tuning the inter-annual variability of the biomass of small pelagic fish species. In this paper we analyse the distribution of eggs and larvae as well as the biological features of the two species of pelagic fish, Engraulis encrasicolus and Sardinella aurita in the north-eastern sector of the Sicily Channel (Mediterranean Sea) from ich…
Vegetated Habitats Trophically Support Early Development Stages of a Marine Migrant Fish in a Coastal Lagoon
2020
Understanding the trophic ecology of early developmental stages of commercial fish species migrating between sea and coastal lagoons is crucial to effective management of nursery habitats and resulting resources. While most information on diet shift of the gilthead seabream Sparus aurata comes from studies in experimental conditions, here we investigated the trophic niche dynamics of post-larvae, juveniles and sub-adults in natural environment, hypothesising that habitat and resources use of marine and lagoonal sites will exhibit strong relationship with ontogeny of the species. Carbon and nitrogen stable isotopes showed evidence of a clear shift in the trophic niche features, trophic posit…
Spatial variability of macrozoobenthic community and trophic structure of a subtropical lagoon on southeastern Brazil's Atlantic coast
2013
The objective of this study was to investigate the macrobenthic community of two compartments of the Maricá-Guarapina lagoon system, along the coast of Rio de Janeiro, Brazil, in relation to its abiotic sediment factors. An additional discrimination between sites was made, wherever the macrophyte Typha domingensis was found. This vegetation supposedly represents a potentially important food source for consumers. Furthermore, the trophic pathways were analyzed functionally by means of stable isotope analysis to assess the role of organic matter sources for consumers in the study area. In conclusion, the results showed differences between abiotic features in the compartments of the lagoon sys…
Spatial variability of stable carbon and nitrogen isotope ratios in a Mediterranean coastal lagoon
2005
Exploring the trophic pathway of organic matter within the Mauguio lagoon (southern France, western Mediterranean), we found spatial differences in the isotopic composition (both δ13C and δ15N values) of organic matter sources (primary producers, particulate and sedimentary organic matter), which were mirrored in the upper trophic levels (invertebrates and fish). On average, δ13C was heavier by about 1.5–2‰ in the location under marine influence than in the sites influenced by freshwater discharge. The opposite trend was found for δ15N, which attained maximum values in the north-central zone influenced by freshwater delivery. For both C and N stable isotope ratios, the highest spatial varia…
Optimality Conditions for Non-Qualified Parabolic Control Problems
1994
We consider parabolic state constrained optimal control problems where the usual Slater condition is not necessarily satisfied. Instead, a weaker interiority property is assumed. Optimality conditions with a Lagrange multiplier are given. As an application we present an augmented Lagrangian algorithm. Numerical test results are included.
Multisite field potential recordings and analysis of the impulse propagation pattern in cardiac cells culture
2007
To provide further insights into the impulse propagation between cardiac myocytes, we performed multiparametric studies of excitation spread with cellular resolution in confluent monolayers of cultured cardiomyocytes (CM). Simultaneous paired intracellular recordings of action potentials in two individual CM revealed slight periodic spontaneous advances/delays in the interspike time lag. Multisite field potential recordings performed with microelectrode arrays (MEA) confirmed random and iterative cycle-to-cycle changes in the direction of excitation spread. These local spontaneous variations in the cardiac impulse propagation pathways may be a safety process protecting against microscopical…
Análisis de la función de los espacios culturales en la redefinición de las políticas culturales de las ciudades. Un estudio de los casos de las área…
2021
Esta tesis aborda la relación entre los espacios culturales y las políticas culturales, específicamente en el ámbito urbano. Concretamente, en este proyecto de investigación argumentamos, en primer lugar, que las políticas culturales urbanas y las políticas de creación de espacios culturales están regidas por una misma lógica se articulan en un todo funcional al paradigma dominante de política cultural (en la que los espacios culturales son a la vez derivada y condición del modelo de democratización cultural). En segundo lugar, sostenemos que los espacios culturales son la clave de bóveda de las políticas de democratización cultural, en tanto que constituyen la herramienta principal de su m…
Fitoplancton de dos lagunas de los humedalesde Xeresa y Xeraco (Valencia, España).
2001
M.Jose.Villena@uv.es Susana.Romo@uv.es Se ha estudiado la composición fitoplanctónica de dos lagunas costeras mediterráneas, que corresponden a los marjales de Xeresa y Xeraco (Valencia). Estas zonas húmedas de la Comunidad Valenciana poseen un importante valor ecológico y botánico para nuestra Península, aunque actualmente se encuentran amenazadas por transformaciones de tipo turístico o agrícola. Las lagunas estudiadas se caracterizan por ser someras (Zmax: 3 m), oligohalinas, de aguas transparentes y mesotróficas, y por encontrarse sobre lechos de turba y con praderas de macrófitos sumergidos. El fitoplancton observado destaca por presentar una composición similar para ambas lagunas, con…
Development of objective non-invasive techniques for the assessment of the ocular surface and tear film dynamics acting as biomarkers for early diagn…
2019
La siguiente disertación supone un trabajo de largo alcance con el propósito de encontrar un nuevo biomarcador de tipo macro que podría ser determinado de forma objetiva y no invasiva como indicador de ojo seco (DED), específicamente en su estado temprano. Para lograr este objetivo, se proponen nuevas métricas de cuantificación de la dinámica lagrimal y se explora el papel fisiopatológico de biomarcadores potenciales en el DED incipiente, mediante el seguimiento visita a visita de tendencias longitudinales de estas medidas durante un periodo de tiempo de un año, en sujetos con sintomatología incipiente. La hipótesis tras el desarrollo de nuevos biomarcadores de tipo macro de DED es que la p…