Search results for "35"
showing 10 items of 2413 documents
Compactness of Fourier integral operators on weighted modulation spaces
2019
Using the matrix representation of Fourier integral operators with respect to a Gabor frame, we study their compactness on weighted modulation spaces. As a consequence, we recover and improve some compactness results for pseudodifferential operators.
On global solutions of the Maxwell-Dirac equations
1987
We prove, for the Maxwell-Dirac equations in 1+3 dimensions, that modified wave operators exist on a domain of small entire test functions of exponential type and that the Cauchy problem, inR+×R3, has a unique solution for each initial condition (att=0) which is in the image of the wave operator. The modification of the wave operator, which eliminates infrared divergences, is given by approximate solutions of the Hamilton-Jacobi equation, for a relativistic electron in an electromagnetic potential. The modified wave operator linearizes the Maxwell-Dirac equations to their linear part.
Negociación, guerra y "asientos". Financiar el elército de Flandes en el último tercio del reinado de Felipe II (1577-1596)
2019
El periodo comprendido entre 1575 y 1596 fue enormemente complejo a nivel político en los Países Bajos y no lo fue menos a nivel financiero para el ejército de Flandes. Estos años estuvieron enmarcados entre dos suspensiones de pagos en los que las negociaciones financieras fueron determinantes para la guerra en los Países Bajos, donde se dirimió la hegemonía hispánica en la Europa del siglo xVI. Estas negociaciones, que se dieron tanto a nivel global como a nivel local, fueron esenciales pagar conseguir aprovisionar al ejército de Flandes y mantener, por extensión, el dominio político y militar en los Países Bajos. Monarquía, ?asientos? y hombres de negocios crearon un cuerpo indivisible q…
Small genomes and the difficulty to define minimal translation and metabolic machineries
2015
The notion of minimal life has sparked the interest of scientists in different fields, ranging from the origin-of-life research to biotechnology-oriented synthetic biology. Whether the interest is focused on the emergence of protocells out of prebiotic systems or the design of a cell chassis ready to incorporate new devices and functions, proposing minimal combinations of genes for life is not a trivial task. Using comparative genomics and biochemistry of endosymbionts (i.e., intracellular mutualistic symbionts) and intracellular parasites, a decade ago we proposed the core of a minimal gene set for a simple heterotrophic cell adapted to a chemically complex environment. In this work, we di…
Communicating Medical Information Online: The Case of Adolescent Health Websites
2020
In recent times, our understanding and practice of public health has been increasingly guided by technological advances generally based on governmental decisions (Green et al. 2009). Not only does the growth of a public system for protecting health hinge upon scientific discovery and dissemination of medical knowledge, but also the World Wide Web has considerably changed the health communication environment. This paper considers the online health information addressed to adolescents. Given that young people have difficulty accessing traditional health services, in theory, the Internet might offer them a more confidential and convenient access to an unprecedented level of information about a…
IL12A, MPHOSPH9/CDK2AP1 and RGS1 are novel multiple sclerosis susceptibility loci
2010
A recent meta-analysis identified seven single-nucleotide polymorphisms (SNPs) with suggestive evidence of association with multiple sclerosis (MS). We report an analysis of these polymorphisms in a replication study that includes 8,085 cases and 7,777 controls. A meta-analysis across the replication collections and a joint analysis with the discovery data set were performed. The possible functional consequences of the validated susceptibility loci were explored using RNA expression data. For all of the tested SNPs, the effect observed in the replication phase involved the same allele and the same direction of effect observed in the discovery phase. Three loci exceeded genome-wide significa…
Global, regional, and national burden of mortality associated with non-optimal ambient temperatures from 2000 to 2019: a three-stage modelling study
2021
Background: Exposure to cold or hot temperatures is associated with premature deaths. We aimed to evaluate the global, regional, and national mortality burden associated with non-optimal ambient temperatures. Methods: In this modelling study, we collected time-series data on mortality and ambient temperatures from 750 locations in 43 countries and five meta-predictors at a grid size of 0·5° × 0·5° across the globe. A three-stage analysis strategy was used. First, the temperature–mortality association was fitted for each location by use of a time-series regression. Second, a multivariate meta-regression model was built between location-specific estimates and meta-predictors. Finally, the gri…
Application of DPSIR framework to analyze the groundwater pollution threats of municipal solid waste: Case study Médiouna Landfill, Morocco
2021
This study addresses the issue of groundwater resources quality affected by solid waste disposed of in the Médiouna dumping site. In this order, we applied the Driving forcePressureStateImpact Response model (DPSIR) model combined with external factors of SWOT analysis (Opportunities and Threats) to assess the environmental impact of waste from Médiouna landfill on groundwater. The analysis study revealed that the continuous demographic expansion and economic growth made solid waste a complex problem. The study highlights the urgent need for implementing new strategies and redesigning more effective, operational and realizable management projects to rehabilitate the Médiouna landfill. In ad…
Estimation of the Amount of Disposed Antibiotics
2019
The impact of the antibiotics in the environment is not well understood yet. Moreover, the total amount of antibiotics that are ending up in the environment as solid waste is not known and cannot be rigorously determined as many variables are influencing the determination of their concentration. The present article is focused on the estimation of the amount of non-prescribed antibiotics that are used in different European countries. Particular attention is paid to the class of beta-lactams, as they are responsible for a considerate share of the antimicrobial resistance. The primary purpose was the estimation of the quantity of non-prescribed antibiotics that might reach the environment as s…
The effect of genetic robustness on evolvability in digital organisms
2008
Abstract Background Recent work has revealed that many biological systems keep functioning in the face of mutations and therefore can be considered genetically robust. However, several issues related to robustness remain poorly understood, such as its implications for evolvability (the ability to produce adaptive evolutionary innovations). Results Here, we use the Avida digital evolution platform to explore the effects of genetic robustness on evolvability. First, we obtained digital organisms with varying levels of robustness by evolving them under combinations of mutation rates and population sizes previously shown to select for different levels of robustness. Then, we assessed the abilit…