21,097 research outputs found
Duality theory and optimal transport for sand piles growing in a silos
We prove existence and uniqueness of solutions for a system of PDEs which
describes the growth of a sandpile in a silos with flat bottom under the action
of a vertical, measure source. The tools we use are a discrete approximation of
the source and the duality theory for optimal transport (or Monge-Kantorovich)
problems
The \infty eigenvalue problem and a problem of optimal transportation
The so-called eigenvalues and eigenfunctions of the infinite Laplacian
are defined through an asymptotic study of that of the usual
-Laplacian , this brings to a characterization via a non-linear
eigenvalue problem for a PDE satisfied in the viscosity sense. In this paper,
we obtain an other characterization of the first eigenvalue via a problem of
optimal transportation, and recover properties of the first eigenvalue and
corresponding positive eigenfunctions
On the consistency of universally non-minimally coupled theories
We discuss the consistency of a recently proposed class of theories described
by an arbitrary function of the Ricci scalar, the trace of the energy-momentum
tensor and the contraction of the Ricci tensor with the energy-momentum tensor.
We briefly discuss the limitations of including the energy-momentum tensor in
the action, as it is a non fundamental quantity, but a quantity that should be
derived from the action. The fact that theories containing non-linear
contractions of the Ricci tensor usually leads to the presence of pathologies
associated with higher-order equations of motion will be shown to constrain the
stability of this class of theories. We provide a general framework and show
that the conformal mode for these theories generally has higher-order equations
of motion and that non-minimal couplings to the matter fields usually lead to
higher-order equations of motion. In order to illustrate such limitations we
explicitly study the cases of a canonical scalar field, a K-essence field and a
massive vector field. Whereas for the scalar field cases it is possible to find
healthy theories, for the vector field case the presence of instabilities is
unavoidable.Comment: Minor changes, version published matching Phys. Rev. D 91 (2015)
104003. 15 pages, no figure
Does local financing make primary schools more efficient : the Philippine case
In the highly centralized system of the Philippines, local funding provides the only source of flexibility to meet specific and urgent needs. The government in Manila, which pays all teacher salaries, finds it easier politically in times of fiscal belt-tightening to cut recurrent costs. Although local funds are a relatively small percentage of the education budget, they make an important contribution to covering maintenence and operating costs. The total cost of education per student also appears to lower in schools with greater local financing. Administrators and teachers have greater incentive to be cost-effective when forced to consider the effect of their behavior on the people who live and work in the local community. The policy implications of these findings for the Philippines, as well as other developing countries, are important. They strongly suggest that decentralization will increase efficiency. Without an increase in local funding, the quality of primary education will suffer.Teaching and Learning,Gender and Education,Primary Education,Health Monitoring&Evaluation,Business in Development
Student performance and school costs in the Philippines'high schools
A key consideration in the policy debate on the appropriate role of private schools in predominantly public school systems is cost effectiveness. The questions are: Do private school students learn more than their counterparts, and is it more or less expensive to educate students in private schools? Taking selectivity into account, the private schools show a significant edge over public schools in both English and Pilipino. Public schools, on the other hand, had a slight advantage in mathematics. A comparison of cost per student reveals a substantial advantage for private schools: public schools in the Philippines spend on average roughly twice as much as private schools. These findings strongly suggest that private schools are an efficient purveyor of secondary education in the formulation of policy measures that could threaten the existence of such schools.Teaching and Learning,Health Monitoring&Evaluation,Gender and Education,Primary Education,Educational Sciences
A network-based approach for predicting key enzymes explaining metabolite abundance alterations in a disease phenotype
<p>Background
The study of metabolism has attracted much attention during the last years due to its relevance in various diseases. The advance in metabolomics platforms allows us to detect an increasing number of metabolites in abnormal high/low concentration in a disease phenotype. Finding a mechanistic interpretation for these alterations is important to understand pathophysiological processes, however it is not an easy task. The availability of genome scale metabolic networks and Systems Biology techniques open new avenues to address this question.</p>
<p>Results
In this article we present a novel mathematical framework to find enzymes whose malfunction explains the accumulation/depletion of a given metabolite in a disease phenotype. Our approach is based on a recently introduced pathway concept termed Carbon Flux Paths (CFPs), which extends classical topological definition by including network stoichiometry. Using CFPs, we determine the Connectivity Curve of an altered metabolite, which allows us to quantify changes in its pathway structure when a certain enzyme is removed. The influence of enzyme removal is then ranked and used to explain the accumulation/depletion of such metabolite. For illustration, we center our study in the accumulation of two metabolites (L-Cystine and Homocysteine) found in high concentration in the brain of patients with mental disorders. Our results were discussed based on literature and found a good agreement with previously reported mechanisms. In addition, we hypothesize a novel role of several enzymes for the accumulation of these metabolites, which opens new strategies to understand the metabolic processes underlying these diseases.</p>
<p>Conclusions
With personalized medicine on the horizon, metabolomic platforms are providing us with a vast amount of experimental data for a number of complex diseases. Our approach provides a novel apparatus to rationally investigate and understand metabolite alterations under disease phenotypes. This work contributes to the development of Systems Medicine, whose objective is to answer clinical questions based on theoretical methods and high-throughput “omics” data.</p>
La musealización del patrimonio natural para su conservación, Museo Luis Mario Schneider, Malinalco, México
El presente artículo desarrolla la importancia del patrimonio natural mediante el trabajo realizado por la Universidad Autónoma del Estado de México, la cual comprende que la educación forma parte esencial en la preservación del entorno natural; es por esta razón que contribuye de manera activa en impulsar la responsabilidad social, al promover el cuidado de éste y otros patrimonios mediante la musealización. El texto resalta el trabajo realizado en el Museo Universitario Dr. Luis Mario Schneider, ubicado en Malinalco, Estado de México, en donde se mencionan aspectos importantes como su arquitectura, guión museográfico, museografía, exposiciones temporales y las diversas áreas que conforman un diseño integral, con el objetivo de considerar este museo como un ejemplo en la generación de nuevos espacios culturales que favorezcan el cuidado del medioambiente. Cabe mencionar el esfuerzo realizado en el proceso de diseño, así como la labor que se realiza cada día para transmitir con calidez el mensaje del museo mediante las visitas guiadas. Lo anterior ha dado como resultado una aceptación que se evidencia en los comentarios del cuaderno dispuesto a los visitantes para compartir sus opiniones sobre el museo, así como en la donación de piezas por parte de los pobladores. El libro de Registro ubicado en el acceso del inmueble, indica un promedio de 27 000 visitantes por año
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