Search results for "35"

Reliable numerical solution of a class of nonlinear elliptic problems generated by the Poisson-Boltzmann equation

2020

We consider a class of nonlinear elliptic problems associated with models in biophysics, which are described by the Poisson-Boltzmann equation (PBE). We prove mathematical correctness of the problem, study a suitable class of approximations, and deduce guaranteed and fully computable bounds of approximation errors. The latter goal is achieved by means of the approach suggested in [S. Repin, A posteriori error estimation for variational problems with uniformly convex functionals. Math. Comp., 69:481-500, 2000] for convex variational problems. Moreover, we establish the error identity, which defines the error measure natural for the considered class of problems and show that it yields computa…

Effect of a Service-Learning Program on the Active Lifestyle of Children with Autism Spectrum Disorder: A Pilot Study

2020

Background: active lifestyles and Physical Activity (PA) are closely related to health. Healthy habits such as being physically active should be consolidated during childhood. Children with Autism Spectrum Disorders (ASD) present fewer opportunities to be involved in PA. For this reason, we conducted a Service-Learning (SL) program to enhance the possibility of participating ASD children enjoying PA sessions. The aim of this study was to analyze and describe the evolution in terms of the frequency and intensity of PA performed by ASD children who participated in the SL program. Methods: we used a quasi-experimental design. The sample was formed by 26 children with ASD (Experimental group: n…

Geostatistical computing of acoustic maps in the presence of barriers

2009

Acoustic maps are the main diagnostic tools used by authorities for addressing the growing problem of urban acoustic contamination. Geostatistics models phenomena with spatial variation, but restricted to homogeneous prediction regions. The presence of barriers such as buildings introduces discontinuities in prediction areas. In this paper we investigate how to incorporate information of a geographical nature into the process of geostatistical prediction. In addition, we study the use of a Cost-Based distance to quantify the correlation between locations.

Identifiability problem for recovering the mortality rate in an age-structured population dynamics model

2014

In this article is studied the identifiability of the age-dependent mortality rate of the Von Foerster–Mc Kendrick model, from the observation of a given age group of the population. In the case where there is no renewal for the population, translated by an additional homogeneous boundary condition to the Von Foerster equation, we give a necessary and sufficient condition on the initial density that ensures the mortality rate identifiability. In the inhomogeneous case, modelled by a non-local boundary condition, we make explicit a sufficient condition for the identifiability property, and give a condition for which the identifiability problem is ill-posed. We illustrate this latter case wit…

Sustainability Assessment of Agricultural Systems in Paraguay: A Comparative Study Using FAO’s SAFA Framework

2019

Sustainability is a topic that is at the center of current discussions in the political, economic, social, and environmental fields. For its analysis, an integral and multidisciplinary vision is needed. This work aims to assess the sustainability of agricultural systems in Paraguay through a comparison applying SAFA (Sustainability Assessment of Food and Agriculture Systems) indicators. The research focuses on 15 case studies on the territory of the Eastern Region of Paraguay divided into five classes of agricultural systems: agribusiness, conventional peasant family farming, agroecological peasant family farming, neo-rural farming, and indigenous agriculture. Data were collected through in…

Managing biotic interactions for ecological intensification of agroecosystems.

2014

9 pages; International audience; Agriculture faces the challenge of increasing food production while simultaneously reducing the use of inputs and delivering other ecosystem services. Ecological intensification of agriculture is a paradigm shift, which has recently been proposed to meet such challenges through the manipulation of biotic interactions. While this approach opens up new possibilities, there are many constraints related to the complexity of agroecosystems that make it difficult to implement. Future advances, which are essential to guide agricultural policy, require an eco-evolutionary framework to ensure that ecological intensification is beneficial in the long term.

The importance of social value in agroecological farms: adjusting the common good balance sheet to improve their sustainable management

2021

Organic farming offers the producers the possibility of focusing on their business while obtaining a competitive advantage. Nevertheless, this is centered in specific activities of the production process, thus only creating environmental value. Therefore, it is not an approach based on sustainability. As a consequence of this, it becomes necessary to enlarge this approach toward people (social value) and profitability (economic value). The objective of this work is to describe a tool based on the Economy for the Common Good model applied to the agroecological sector. We propose to adapt the Common Good Matrix to the characteristics of agroecological farms to offer a useful tool to manage an…

Juuresta suurpuuhun : Jyväskylän puutyöläisten ammattiyhdistystoiminta vuosina 1899-1999

1999

Respirometric Index and Biogas Potential of Different Foods and Agricultural Discarded Biomass

2016

The biological stability of biomass is an important parameter for treatment plant design, process control or compost use. Measuring the biological reactivity of waste with the help of indicators such as respirometric indexes (RI) becomes an important tool to prevent the significant environmental impact of biodegradable wastes in accordance with European legislation. The aim of this paper is to show the importance of the RI technique as a tool to establish further uses of biomass such as fertilizer or biogas. The respirometric process length for different types of biomass (grape marc, apple pomace and olive pomace) was quantified. Higher moisture content seemed to favor the biological activi…

Angiokeratoma: decision-making aid for the diagnosis of Fabry disease

2012

Isolated angiokeratomas are common benign cutaneous lesions, generally deemed unworthy of further investigation. In contrast, diffuse angiokeratomas should alert the physician to a possible diagnosis of Fabry disease, a rare X-linked lysosomal storage disorder, characterized by a-galactosidase deficiency. Glycosphingolipids accumulate in cells throughout the body resulting in progressive multi-organ failure. Difficulties are encountered when trying to interpret the significance of angiokeratomas because they may also occur in other lysosomal storage disorders and rarely in an isolated manner in Fabry disease. We present an algorithm for the classification of angiokeratomas which might prove…