Modélisation et prévision du taux de change canadien à l'aide du modèle ESTAR

Rapport de recherche présenté à la Faculté des arts et des sciences en vue de l'obtention du grade de Maîtrise en sciences économiques

Surface mixing and biological activity in the four Eastern Boundary Upwelling Systems

Eastern Boundary Upwelling Systems (EBUS) are characterized by a high productivity of plankton associated with large commercial fisheries, thus playing key biological and socio-economical roles. The aim of this work is to make a comparative study of these four upwelling systems focussing on their surface stirring, using the Finite Size Lyapunov Exponents (FSLEs), and their biological activity, based on satellite data. First, the spatial distribution of horizontal mixing is analysed from time averages and from probability density functions of FSLEs. Then we studied the temporal variability of surface stirring focussing on the annual and seasonal cycle. There is a global negative correlation between surface horizontal mixing and chlorophyll standing stocks over the four areas. To try to better understand this inverse relationship, we consider the vertical dimension by looking at the Ekman-transport and vertical velocities. We suggest the possibility of a changing response of the phytoplankton to sub/mesoscale turbulence, from a negative effect in the very productive coastal areas to a positive one in the open ocean.Comment: 12 pages. NPG Special Issue on "Nonlinear processes in oceanic and atmospheric flows". Open Access paper, available also at the publisher site: http://www.nonlin-processes-geophys.net/16/557/2009

Surrounding effects and sensitivity of the CODALEMA experiment

International audienceFuture autonomous systems of cosmic ray radiodetection will be installed over large areas, encountering various environmental and noise conditions. It is thus essential to check and evaluate the influence of the vicinity on the sensitivity of detection. In this paper, the main environmental influences on the performances of the CODALEMA experiment are presented. It will be shown that the performances and sensitivity of the detector are not affected by the environment, and that the new CODALEMA autonomous detection station can reach the ultimate accessible sensitivity even in a quite noisy environment. This allows deconvolving the detector's response and recovering the real spectral characteristics of the cosmic ray air showers

Effective field theory of the deuteron with dibaryon field

Pionless effective field theory with dibaryon fields is reexamined for observables involving the deuteron. The electromagnetic form factors of the deuteron and the total cross sections of radiative neutron capture on the proton, $np \to d\gamma$, are calculated. The low energy constants of vector(photon)-dibaryon-dibaryon vertices in the effective lagrangian are fixed primarily by the one-body vector(photon)-nucleon-nucleon interactions. This scheme for fixing the values of the low energy constants satisfactorily reproduces the results of the effective range theory. We also show that, by including higher order corrections, one can obtain results that are close to those of Argonne v18 potential model.Comment: 25 pages and 11 figures; 16 references added, Figure 6 and 7 replotted, text revised a lot. To be published in Phys. Rev.

Electromagnetic structure of the deuteron: review of recent theoretical and experimental results

This talk reviews recent theoretical and experimental results for elastic electron deuteron scattering (yielding the deuteron form factors), threshold electrodisintegration ($e+d\to e'+p+n$ where the mass of the final $np$ pair, $W$, is only a few MeV above the threshold value of $m_p+m_n$), and high energy deuteron photodisintegration ($\gamma+d\to p+n$). The talk is based on the complete reviews of Refs. [GVO,S,GG], with a few new results not previously reported.Comment: 6 pages, 10 figures, Invited talk for Workshop on Electron Nucleus Scattering VII, Elba, Italy, 200

Espacialização de indicadores socioeconômicos como subsídio ao macrozoneamento ecológico-econômico do Estado do Maranhão.

Macrozoneamentos ecológico-econômicos foram instituídos pelo governo federal e têm como finalidade identificar potencialidades e limitações de recursos naturais e da sociedade com base em um diagnóstico socioambiental e com o propósito de apoiar a formulação e execução de políticas de desenvolvimento regional . Indicadores socioeconômicos são instrumentos importantes em todas as fases do processo de formulação, implementação, monitoramento e avaliação das políticas públicas, e são elementos indispensáveis para a elaboração de macrozoneamentos ecológico-econômicos . O objetivo deste trabalho foi espacializar indicadores socioeconômicos que serão utilizados como subsídio para a elaboração do Macrozoneamento Ecológico-Econômico do Estado do Maranhão. Foram adotados, como unidade de referência territorial, os 217 municípios que compõem o estado e, como fonte de dados, a Produção Agrícola Municipal (PAM) do IBGE e o Censo Demográfico do IBGE. Foram selecionados os principais indicadores socioeconômicos, como saneamento básico, energia, água potável, saúde, educação, entre outros. O procedimento metodológico utilizado foi: definição e levantamento dos indicadores; criação e formatação das tabelas com auxílio do programa Excel; e, por fim, a utilização do software ArcGIS (ESRI), que, por meio das planilhas criadas, dos geocódigos municipais e dos shapefile disponibilizados pelo IBGE, possibilitou espacializar os dados e, assim, gerar os mapas temáticos. A espacialização dos indicadores pode contribuir para a formulação de políticas públicas em diferentes níveis de governo e, assim, para que sejam tomadas decisões mais adequadas

Sensitivity of ecosystem parameters to simulated satellite ocean colour data using a coupled physical-biological model of the North Atlantic

A means of assimilating simulated satellite ocean color data with a coupled physical-biological model of the North Atlantic Ocean is implemented, allowing the relative sensitivities of different biological parameters to those data to be investigated. The model consists of an eddy-permitting general circulation model derived from the WOCE Community Modeling Effort and a nitrogen-based, four-compartment NPZD marine ecosystem model. Many of the parameters in marine ecosystem models are poorly known and via assimilation, we hope to better constrain their values. The control parameters chosen for the variational assimilation are the model parameters involved in parameterizations of recycling as these are the most poorly known. Simulated observations are taken while following several floats seeded in varying dynamical biogeochemical provinces of the North Atlantic model domain over a six-month period. Twin experimental results show that, for the given functional forms of growth, mortality and grazing, the following parameters can be successfully recovered from simulated satellite ocean color data: nitrate and detrital recycling parameters in the trade wind domain, zooplankton parameters at higher latitudes (westerly wind and polar domains), and the phytoplankton mortality rate in all regions. By simultaneously assimilating ocean color data in different biological provinces, it becomes possible to successfully constrain all ecosystem parameters at once

Energy-Process Integration of the Gas-Cooled/Water-Cooled Fixed-Bed Reactor Network for Methanol Synthesis

The paper deals with the techno-economical assessment of the gas-cooled/water-cooled fixed-bed reactor network for methanol synthesis. The study is the extension of the first-principles model for the watercooled reactor already proposed in our prior work (Manenti et al., 2013). Here, the optimization is extended to the steam generation and the reactor length ratio. As a result, basing on the integrated optimization of energy and process yield, we propose to significantly revise the common design. The traditional water/gas cooling reactor length ratio could be significantly reduced with consequent simultaneous increase in methanol production and steam generation as well, however preserving safety and operational ranges. The economic benefit deriving from the proposed design for a medium-scale process is estimated in more than 1.7 M€/y

Variational Calculations using Low-Momentum Potentials with Smooth Cutoffs

Recent variational calculations of the deuteron and the triton illustrate that simple wave function ansatze become more effective after evolving the nucleon-nucleon potential to lower momentum (``V_lowk''). However, wave function artifacts from the use of sharp cutoffs in relative momentum decrease effectiveness for small cutoffs (< 2 fm^-1) and slow down convergence in harmonic oscillator bases. These sharp cutoff artifacts are eliminated when V_lowk is generated using a sufficiently smooth cutoff regulator.Comment: 11 pages, 4 figure