Economic Evaluation and Biodiversity Conservation of Animal Genetic Resources

Rapidly declining biodiversity has made international and national policies focus on the question of how best to protect genetic resources. Loss of biodiversity does not only concern wildlife, but equally affects agriculturally used species. These species, of foremost importance for the subsistence of humankind, are subject to pressures sometimes similar and sometimes very distinct from those of their wild counterparts. And so are the losses implied by this decline in diversity. This handbook was conceived within the project Sustainable conservation of animal genetic resources in marginal rural areas: Integrating molecular genetics, socio-economics and geostatistical approaches (ECONOGENE – EC-QLK5-CT-2001-02461) to review and design methods that can serve as a basis to guide conservation policies for livestock breeds at risk of extinction. It is part of the broader effort of a multidisciplinary research team assessing the diversity of European sheep and goat breeds. The final goal of the project is to assess the impact of current and future policies on these breeds. --

Augmented fluid-structure interaction systems for viscoelastic pipelines and blood vessels

[EN] In this work, innovative 1D hyperbolic models able to predict the behavior of the fluid-structure interaction mechanism that underlies the dynamics of flows in different compliant ducts are presented. Starting from the study of plastic water pipelines, the proposed tool is then applied to the biomathematical field to reproduce the mechanics of blood flow in both arteries and veins. With this aim, various different viscoelastic models have been applied and extended to obtain augmented fluid-structure interaction systems in which the constitutive equation of the material is directly embedded into the system as partial differential equation. These systems are solved recurring to Finite Volume Methods that take into account the recent evolution in the computational literature of hyperbolic balance laws systems. To avoid the loss of accuracy in the stiff regimes of the proposed systems, asymptotic-preserving Implicit-Explicit Runge-Kutta schemes are considered for the time discretization, which are able to maintain the consistency and the accuracy in the diffusive limit, without restrictions due to the scaling parameters.Bertaglia, G. (2022). Augmented fluid-structure interaction systems for viscoelastic pipelines and blood vessels. En Proceedings of the YIC 2021 - VI ECCOMAS Young Investigators Conference. Editorial Universitat Politècnica de València. 431-438. https://doi.org/10.4995/YIC2021.2021.13450OCS43143

Asymptotic-Preserving Neural Networks for hyperbolic systems with diffusive scaling

With the rapid advance of Machine Learning techniques and the deep increase of availability of scientific data, data-driven approaches have started to become progressively popular across science, causing a fundamental shift in the scientific method after proving to be powerful tools with a direct impact in many areas of society. Nevertheless, when attempting to analyze dynamics of complex multiscale systems, the usage of standard Deep Neural Networks (DNNs) and even standard Physics-Informed Neural Networks (PINNs) may lead to incorrect inferences and predictions, due to the presence of small scales leading to reduced or simplified models in the system that have to be applied consistently during the learning process. In this Chapter, we will address these issues in light of recent results obtained in the development of Asymptotic-Preserving Neural Networks (APNNs) for hyperbolic models with diffusive scaling. Several numerical tests show how APNNs provide considerably better results with respect to the different scales of the problem when compared with standard DNNs and PINNs, especially when analyzing scenarios in which only little and scattered information is available.Comment: arXiv admin note: text overlap with arXiv:2206.1262

Nonconforming Virtual Element basis functions for space-time Discontinuous Galerkin schemes on unstructured Voronoi meshes

We introduce a new class of Discontinuous Galerkin (DG) methods for solving nonlinear conservation laws on unstructured Voronoi meshes that use a nonconforming Virtual Element basis defined within each polygonal control volume. The basis functions are evaluated as an L2 projection of the virtual basis which remains unknown, along the lines of the Virtual Element Method (VEM). Contrarily to the VEM approach, the new basis functions lead to a nonconforming representation of the solution with discontinuous data across the element boundaries, as typically employed in DG discretizations. To improve the condition number of the resulting mass matrix, an orthogonalization of the full basis is proposed. The discretization in time is carried out following the ADER (Arbitrary order DERivative Riemann problem) methodology, which yields one-step fully discrete schemes that make use of a coupled space-time representation of the numerical solution. The space-time basis functions are constructed as a tensor product of the virtual basis in space and a one-dimensional Lagrange nodal basis in time. The resulting space-time stiffness matrix is stabilized by an extension of the dof-dof stabilization technique adopted in the VEM framework, hence allowing an element-local space-time Galerkin finite element predictor to be evaluated. The novel methods are referred to as VEM-DG schemes, and they are arbitrarily high order accurate in space and time. The new VEM-DG algorithms are rigorously validated against a series of benchmarks in the context of compressible Euler and Navier-Stokes equations. Numerical results are verified with respect to literature reference solutions and compared in terms of accuracy and computational efficiency to those obtained using a standard modal DG scheme with Taylor basis functions. An analysis of the condition number of the mass and space-time stiffness matrix is also forwarded

Multiscale constitutive framework of 1D blood flow modeling: Asymptotic limits and numerical methods

In this paper, a multiscale constitutive framework for one-dimensional blood flow modeling is presented and discussed. By analyzing the asymptotic limits of the proposed model, it is shown that different types of blood propagation phenomena in arteries and veins can be described through an appropriate choice of scaling parameters, which are related to distinct characterizations of the fluid-structure interaction mechanism (whether elastic or viscoelastic) that exist between vessel walls and blood flow. In these asymptotic limits, well-known blood flow models from the literature are recovered. Additionally, by analyzing the perturbation of the local elastic equilibrium of the system, a new viscoelastic blood flow model is derived. The proposed approach is highly flexible and suitable for studying the human cardiovascular system, which is composed of vessels with high morphological and mechanical variability. The resulting multiscale hyperbolic model of blood flow is solved using an asymptotic-preserving Implicit-Explicit Runge-Kutta Finite Volume method, which ensures the consistency of the numerical scheme with the different asymptotic limits of the mathematical model without affecting the choice of the time step by restrictions related to the smallness of the scaling parameters. Several numerical tests confirm the validity of the proposed methodology, including a case study investigating the hemodynamics of a thoracic aorta in the presence of a stent

Hyperbolic models for the spread of epidemics on networks: kinetic description and numerical methods

We consider the development of hyperbolic transport models for the propagation in space of an epidemic phenomenon described by a classical compartmental dynamics. The model is based on a kinetic description at discrete velocities of the spatial movement and interactions of a population of susceptible, infected and recovered individuals. Thanks to this, the unphysical feature of instantaneous diffusive effects, which is typical of parabolic models, is removed. In particular, we formally show how such reaction-diffusion models are recovered in an appropriate diffusive limit. The kinetic transport model is therefore considered within a spatial network, characterizing different places such as villages, cities, countries, etc. The transmission conditions in the nodes are analyzed and defined. Finally, the model is solved numerically on the network through a finite-volume IMEX method able to maintain the consistency with the diffusive limit without restrictions due to the scaling parameters. Several numerical tests for simple epidemic network structures are reported and confirm the ability of the model to correctly describe the spread of an epidemic

Integrated Pest Management Portfolios in UK Arable Farming: Results of a Farmer Survey

BACKGROUND. Farmers are faced with a wide range of pest management (PM) options which can be adopted in isolation or alongside complement or substitute strategies. This paper presents the results of a survey of UK cereal producers focusing on the character and diversity of PM strategies currently used by, or available to, farmers. In addition, the survey asked various questions pertaining to agricultural policy participation, attitude toward environmental issues, sources of PM advice and information and the important characteristics of PM technologies. RESULTS. The results indicate that many farmers do make use of a suite of PM techniques and that their choice of integrated PM (IPM) portfolio appears to be jointly dictated by farm characteristics and Government policy. Results also indicate that portfolio choice does affect the number of subsequent insecticide applications per crop. CONCLUSIONS. These results help to identify the type of IPM portfolios considered adoptable by farmers and highlight the importance of substitution in IPM portfolios. As such, these results will help to direct R&D effort toward the realisation of more sustainable PM approaches and aid the identification of potential portfolio adopters. These findings highlight the opportunity a revised agri-environmental policy design could generate in terms of by enhancing coherent IPM portfolio adoption.Pest management; pesticide alternatives; technology and portfolio approaches;

Atrial high-rate episodes: prevalence, stroke risk, implications for management, and clinical gaps in evidence

Self-terminating atrial arrhythmias are commonly detected on continuous rhythm monitoring, e.g. by pacemakers or defibrillators. It is unclear whether the presence of these arrhythmias has therapeutic consequences. We sought to summarize evidence on the prevalence of atrial high-rate episodes (AHREs) and their impact on risk of stroke. We performed a comprehensive, tabulated review of published literature on the prevalence of AHRE. In patients with AHRE, but without atrial fibrillation (AF), we reviewed the stroke risk and the potential risk/benefit of oral anticoagulation. Atrial high-rate episodes are found in 10-30% of AF-free patients. Presence of AHRE slightly increases stroke risk (0.8% to 1%/year) compared with patients without AHRE. Atrial high-rate episode of longer duration (e.g. those >24 h) could be associated with a higher stroke risk. Oral anticoagulation has the potential to reduce stroke risk in patients with AHRE but is associated with a rate of major bleeding of 2%/year. Oral anticoagulation is not effective in patients with heart failure or survivors of a stroke without AF. It remains unclear whether anticoagulation is effective and safe in patients with AHRE. Atrial high-rate episodes are common and confer a slight increase in stroke risk. There is true equipoise on the best way to reduce stroke risk in patients with AHRE. Two ongoing trials (NOAH-AFNET 6 and ARTESiA) will provide much-needed information on the effectiveness and safety of oral anticoagulation using non-vitamin K antagonist oral anticoagulants in patients with AHRE.info:eu-repo/semantics/publishedVersio