3,893 research outputs found
Random attractors for stochastic 2D-Navier-Stokes equations in some unbounded domains
We show that the stochastic flow generated by the Stochastic Navier-Stokes
equations in a 2-dimensional Poincar\'e domain has a unique random attractor.
This result complements a recent result by Brze\'zniak and Li [10] who showed
that the flow is asymptotically compact and generalizes a recent result by
Caraballo et al. [12] who proved existence of a unique pullback attractor for
the time-dependent deterministic Navier-Stokes equations in a 2-dimensional
Poincar\'e domain
Participatory Plant Breeding in Uruguay
The introduction of forage legumes into the native pastures of Uruguay is considered an environmentally safe method with which to increase the level of production through the addition of biologically fixed nitrogen. An integrated plant breeding programme was initiated at INIA (National Agricultural Research Institute), Uruguay, with the aim of developing forage legumes able to persist and produce in co-existence with the native (grass dominant) vegetation under cattle and sheep grazing. The programme was conducted in parallel with rhizobial strain selection. During 1998 to 2001 at Glencoe Research Station (32o 01\u2732 S lat; 57o 00o 39 W long), 326 temperate and subtropical forage legume species were evaluated in the basaltic region of Uruguay. This study provided a set of data with which the legume species could be ranked according to their performance (Real et al., 2004) so that the best 10% could be selected for further evaluation and breeding. The best species according to objectively measured characters (i.e. forage and seed yield) could be very valuable to certain farming systems and farmers, but might be of little value for other farmers and their systems. A significant relationship between the farm decision making unit and the farming systems has been reported for this region (Ferreira, 1997). Participatory research has proved to be an effective way to include farmers\u27 local knowledge in plant breeding programmes (Dusseldorp & Box, 1993).Therefore, to aid the conventional plant breeding approach, a farmer participatory breeding group was formed
Phylogeographic Triangulation: Using Predator-Prey-Parasite Interactions to Infer Population History from Partial Genetic Information
Phylogeographic studies, which infer population history and dispersal movements from intra-specific spatial genetic
variation, require expensive and time-consuming analyses that are not always feasible, especially in the case of rare or
endangered species. On the other hand, comparative phylogeography of species involved in close biotic interactions may
show congruent patterns depending on the specificity of the relationship. Consequently, the phylogeography of a parasite
that needs two hosts to complete its life cycle should reflect population history traits of both hosts. Population movements
evidenced by the parasite’s phylogeography that are not reflected in the phylogeography of one of these hosts may thus be
attributed to the other host. Using the wild rabbit (Oryctolagus cuniculus) and a parasitic tapeworm (Taenia pisiformis) as an
example, we propose comparing the phylogeography of easily available organisms such as game species and their specific
heteroxenous parasites to infer population movements of definitive host/predator species, independently of performing
genetic analyses on the latter. This may be an interesting approach for indirectly studying the history of species whose
phylogeography is difficult to analyse directly
Structuring targeted surveillance for monitoring disease emergence by mapping observational data onto ecological process
An efficient surveillance system is a crucial factor in identifying, monitoring and tackling outbreaks of infectious diseases. Scarcity of data and limited amounts of economic resources require a targeted effort from public health authorities. In this paper, we propose a mathematical method to identify areas where surveillance is critical and low reporting rates might leave epidemics undetected. Our approach combines the use of reference-based susceptible-exposed-infectious models and observed reporting data;We propose two different specifications, for constant and time-varying surveillance, respectively. Our case study is centred around the spread of the raccoon rabies epidemic in the state of New York, using data collected between 1990 and 2007. Both methods offer a feasible solution to analyse and identify areas of intervention
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