2,997 research outputs found
Injection-suction control for Navier-Stokes equations with slippage
We consider a velocity tracking problem for the Navier-Stokes equations in a
2D-bounded domain. The control acts on the boundary through a injection-suction
device and the flow is allowed to slip against the surface wall. We study the
well-posedness of the state equations, linearized state equations and adjoint
equations. In addition, we show the existence of an optimal solution and
establish the first order optimality condition.Comment: 23 page
Expression of homoeologous molecular systems in wheat alloploids
Allopolyploidy is widespread in the plant kingdom, where it has been of considerable evolutionary significance. Although the existence of heterotic interactions between the genomes that make up an alloploid have been generally assumed, the precise nature of these interactions has not been extensively investigated. Presently available evidence about metabolic integration of the wheat genomes is examined in search of new insights about the different modes of genome interaction. Although additive expression seems to be the case for many homoeologous systems, more complex patterns of integration have become evident. Examples of enzyme subunit complementation, gene compensation and other dosage effects, holoprotein completion, and complementation of metabolic pathways are discussed
Assessment of the Sustainability of Extensive Livestock Farms on the Common Grasslands of the Natural Park Sierra de Grazalema
The communal pastures of the Natural Park Sierra de Grazalema are grazed by a total of 23 extensive herds, of which 75% are certified as organic, although only 39% are subsidized for being organic. In a previous research work, these farms were characterized and classified into four typologies: group 1 (farms of intermediate size and without sheep), group 2 (large and very extensive farms), group 3 (farms with sheep suitable for both meat and milk) and group 4 (farms with dairy goat milk and without cattle). In this article, the sustainability of these farms is evaluated and compared based on their organic orientation (whether they are organic or conventional) and their typology (the four typologies indicated), as a tool for decision-making in the management of this natural protected area. To do so, 49 sustainability indexes have been generated, grouped into five attributes: adaptability, self-management, equity, stability, and productivity. The results indicate that, at the global level, there are no significant differences in sustainability between the organic and conventional farms studied. In contrast, depending on the typologies, the results indicate that group 3 is the most sustainable, followed by groups 1 and 4, with group 2 being the one with the lowest level of sustainability. Taking into account that there are a reduced number of herds grazing in this natural park, it is essential to solve the weaknesses of these farms in order to guarantee that they continue to maintain environmental equilibrium in the grasslands
A Typological Characterization of Organic Livestock Farms in the Natural Park Sierra de Grazalema Based on Technical and Economic Variables
This paper describes the typological characterization of the Natural Park Sierra de Grazalema (NPSG) livestock farms using its communal pastures (N = 23, 100% of population) in order to study their sustainability from 160 technical, economic and social variables (from direct on-farm data collection). A principal components analysis (PCA) produced four principal components related to size, livestock species, main productions and intensification level, explaining 73.6% of the variance. The subsequent cluster analysis classified the farms into four groups: C1 (medium size farms without sheep), C2 (large size and very extensive farms), C3 (farms with multipurpose sheep) and C4 (farms with dairy goat and without cattle). Forty-eight-point-seven percent of the surface was registered as organic but none of the farms’ commercialized products were organic. C2 and C3 (both having three ruminant species) are those farms that have more economic differences, the former generating the lowest profit, and the latter generating the highest; however, there is a risk to grasslands conservation from the current tendency that leads dairy farms to rapid intensification. Nevertheless, the very extensive farms are the most interesting for NPSG conservation and the administration should help to maintain the profitability of this sustainable traditional activity, which is necessary to conserve communal pastures
Top-down cascading effects driven by the odontocetes in the Gulf of Taranto (Northern Ionian Sea, Central Mediterranean Sea)
An investigation of the marine food web in the Gulf of Taranto (Northern Ionian Sea, Central Mediterranean Sea) was carried out to explore the top-down cascading effects driven by the Odontocetes. The food web was analysed by a mass-balance model using 51 functional groups and detailing the trophic impacts of the striped and common bottlenose dolphins, the Risso's dolphin and the sperm whale during the period 2010-2014. Odontocetes resulted top-predators with the highest TL estimated for the Risso's dolphin (TL=5.40) and the lowest for the common bottlenose dolphin (TL=4.47). The striped dolphin played the highest top-down control, showing cascading effects up to the 3rd TL. The Risso's dolphin and the sperm whale played similar cascading effects, but weaker than the striped dolphin. Understanding pattern and strengthen of trophic controls played by the Odontocetes within the food web could contribute to identify the basal mechanisms involved in the ecosystem functioning
Fokker-Planck type equations with Sobolev diffusion coefficients and BV drift coefficients
In this paper we give an affirmative answer to an open question mentioned in
[Le Bris and Lions, Comm. Partial Differential Equations 33 (2008),
1272--1317], that is, we prove the well-posedness of the Fokker-Planck type
equations with Sobolev diffusion coefficients and BV drift coefficients.Comment: 11 pages. The proof has been modifie
Nitrogen sources on growth, production and quality of essential oil in cymbopogon citratus and cymbopogon flexuosus.
Poster 009. SBOE 2015
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