Time resolved pattern evolution in a large aperture laser

We have measured quasi-instantaneous transverse patterns in a broad aperture laser. Non-ordered patterns yielding to boundary determined regular structures in progressive time-integrated recording are observed. The linear analysis and numerical integration of the full Maxwell-Bloch equations allow us to interpret the features of the experiment. We show that this system being far from threshold cannot be fully understood with a perturbative model.Comment: 7 pages, 5 GIF figures . To be published in Phys. Rev. Let

Winter precipitation over the Iberian peninsula and its relationship to circulation indices

International audienceWinter precipitation variability over the Iberian peninsula was investigated by obtaining the spatial and temporal patterns. Empirical Orthogonal Functions were used to describe the variance distribution and to compress the precipitation data into a few modes. The corresponding spatial patterns divide the peninsula into climatic regions according to precipitation variations. The associated time series were related to large scale circulation indices and tropical sea surface temperature anomalies by using lag cross-correlation and cross-spectrum. The major findings are: the most influential indices for winter precipitation were the North Atlantic Oscillation and the East Atlantic/West Russian pattern; coherent oscillations were detected at about eight years between precipitation and the North Atlantic Oscillation and some dynamic consequences of the circulation on precipitation over the Iberian peninsula were examined during drought and wet spells. In the end statistical methods have been proposed to downscale seasonal precipitation prediction. Keywords: Winter precipitation, circulation indices, Iberian peninsula climate, climate variations, precipitation tren

pH e condutividade elétrica da solução do solo em dendezais e floresta primária da Amazônia brasileira.

O estudo da solução do solo está relacionado ao fato de que as plantas, predominantemente, absorvem os nutrientes que estão na solução do solo, além de fornecer indicadores de fertilidade e do potencial de hidrogênio (pH). Com o objetivo de avaliar a dinâmica do pH e da condutividade elétrica da solução do solo em dendezais e na floresta primária, foi instalado um experimento no Campo experimental do Rio Urubu (CERU), município de Rio Preto da Eva, Estado do Amazonas, Brasil

Carregando dados na arquitetura data warehousing - armazém de dados de frutas.

Data warehouse / Data Mart. Arquiteturas. O processo ETT (Extração, Transformação e carga de dados).bitstream/CNPTIA/9176/1/COMNICADOTEC3_0.pdfAcesso em: 29 maio 2008

A Through-Life Cost Analysis Model to Support Investment Decision-Making in Concentrated Solar Power Projects

This research paper aims to propose a through-life cost analysis model for estimating the profitability of renewable concentrated solar power (CSP) technologies. The financial outputs of the model include net present value (NPV) and benefit-cost ratio (BCR) of the project, internal rate of return (IRR) and discounted payback period (DPBP) of the investment, and levelized cost of energy (LCoE) from the CSP technology. The meteorological data for a specific location in the city of Tucson in Arizona is collected from a network of automated weather stations, and the NREL System Advisor Model (SAM) is applied to simulate hourly energy output of the CSP plant. An Excel spreadsheet tool is designed to calculate, in a bottom-up approach, the financial metrics required for approval of CSP projects. The model is tested on a 50MW parabolic trough CSP plant and the results show an annual energy production of 456,351,232 kWh, NPV of over $64 million and LCoE of 0.16$/kWh. Finally, a sensitivity analysis is performed to identify the factors which have the most significant effect on the economic performance of CSP technologies. The proposed model can provide valuable guidance to support the strategic planning and investment decision-making in CSP projects

Dinâmica do carbono e nutrientes em solos sob floresta primária e em áreas com diferentes idades de reflorestamento na Província Petrolífera de Urucu, Coari - AM.

O objetivo deste estudo foi caracterizar e avaliar a dinâmica do carbono e dos nutrientes na camada superficial de solos sob floresta primária e em áreas com diferentes idades de reflorestamento na Província Petrolífera de Urucu, município de Coari - AM

The {\L}ojasiewicz exponent of a set of weighted homogeneous ideals

We give an expression for the {\L}ojasiewicz exponent of a set of ideals which are pieces of a weighted homogeneous filtration. We also study the application of this formula to the computation of the {\L}ojasiewicz exponent of the gradient of a semi-weighted homogeneous function (\C^n,0)\to (\C,0) with an isolated singularity at the origin.Comment: 15 page