Radiation Pressure Induced Instabilities in Laser Interferometric Detectors of Gravitational Waves

The large scale interferometric gravitational wave detectors consist of Fabry-Perot cavities operating at very high powers ranging from tens of kW to MW for next generations. The high powers may result in several nonlinear effects which would affect the performance of the detector. In this paper, we investigate the effects of radiation pressure, which tend to displace the mirrors from their resonant position resulting in the detuning of the cavity. We observe a remarkable effect, namely, that the freely hanging mirrors gain energy continuously and swing with increasing amplitude. It is found that the `time delay', that is, the time taken for the field to adjust to its instantaneous equilibrium value, when the mirrors are in motion, is responsible for this effect. This effect is likely to be important in the optimal operation of the full-scale interferometers such as VIRGO and LIGO.Comment: 27 pages, 11 figures, RevTex styl

Utilização da ferramenta ?Socialização do Levantamento de Expectativas? (SLE) no desenvolvimento de Projetos, Programas e Cursos.

By contextualizing the ramifications of government public policies on planning, development and evaluation of capacity-building programs and projects and on technology transfer and dissemination, under Embrapa Strategic Studies and Training?s scope of action, and under the expansion of South-South dialogue, this article aims to explore the connection between the different contingencies to which such programs, projects and courses are subjected, and the development of educational solutions or even innovating educational technologies to increase effectiveness and efficiency of these capacity-building actions and thus of their impacts. Herein we specifically analyze the use of the tool "Socialization of the Survey of Expectations" (SSE) with stakeholders (participants, instructors and organizers) in one of these projects, treated here as a case study: the International Course "Sustainable Coconut Production System and Fruit and Vegetables Quality Classification", jointly held by the Ministry of Agriculture, the Brazilian Cooperation Agency of the Ministry of Foreign Affairs, Embrapa Coastal Tablelands and Embrapa Strategic Studies and Training

A high accuracy method for the simulation of non-ideal optical cavities

We present an algorithm able to represent with a high accuracy any kind of stable cavity, even when many static or dynamical defects are present, like misalignments, curvature errors, surface irregularities, substrate inhomogeneities... We first present the theory, giving ideas on its validity domain, and a discussion of its accuracy in terms of a RMS phase error, which is found to be negligible compared to the phase noise due to roughness of optical surfaces. Then we show that the well-known features of ideal resonant cavities are found by the algorithm with a good accuracy. This tool can help for designing laser cavities, mode cleaners, or passive Fabry-Perot standards ; as an example, some results are presented concerning the design of a very long cavity planned for interferometric purposes

Exercício parcial de avaliação de impactos de políticas públicas em cooperação técnica internacional Sul-Sul: um estudo de caso.

Neste artigo utilizou-se a metodologia ?Modelo de Quatro Níveis? de Kirkpatrick, em três de suas quatro dimensões, na avaliação de reação, avaliação de aprendizagens, e avaliação de impacto, em um exercício de análise finalística qualitativa do processo de desdobramento e aplicação da Política Pública (PP) de Cooperação Internacional (COOPTEC) Sul-Sul do Ministério das Relações Exteriores (MRE) do Governo Brasileiro, avaliando dois cursos ofertados através da Agência Brasileira de Cooperação (ABC), e executados pela Embrapa Estudos e Capacitação (EEC), em 2012. Apesar do restrito tamanho da amostra impedir ampla generalização dos resultados, ao final sugere-se que a PP de COOPTEC internacional adotada pelo Governo brasileiro seja mais bem avaliada e acompanhada no alcance de seu principal objetivo de gerar impactos em profundidade, capilaridade e em extensão aos países beneficiários, definindo novos horizontes e possibilidades de efetiva transformação social, colocando o Brasil efetivamente no rol de países doadores emergentes. Para isso, também constatou-se que, no contexto do Policy Cycle, avaliar impactos de PPs exige análises estruturais complexas, em várias dimensões, envolvendo métricas bem ajustadas, acompanhamento e melhoria contínua em realimentação do processo em curso, assim como análises políticas articuladas de forma dialética e dialógica frente às intencionalidades tácitas e explícitas da PP e dos seus programas, ampliando seus outputs e outcomes e, consequentemente, seus futuros impactos

Compensation of Strong Thermal Lensing in High Optical Power Cavities

In an experiment to simulate the conditions in high optical power advanced gravitational wave detectors such as Advanced LIGO, we show that strong thermal lenses form in accordance with predictions and that they can be compensated using an intra-cavity compensation plate heated on its cylindrical surface. We show that high finesse ~1400 can be achieved in cavities with internal compensation plates, and that the cavity mode structure can be maintained by thermal compensation. It is also shown that the measurements allow a direct measurement of substrate optical absorption in the test mass and the compensation plate.Comment: 8 page

Considerações estruturais sobre o exercício do cargo da presidência das comissões de ética do Sistema de Gestão da Ética do Poder Executivo Federal (SGEPEF).

Este artigo busca sistematizar conhecimentos advindos do exercício da presidência de comissão de ética de instituição pública de ciência e tecnologia, pivô de articulação e integração de inúmeros vetores, ao reunir aprendizagens, princípios e diretrizes, com o objetivo de delinear novas linhas de ação aos ocupantes desse cargo. Partindo do pressuposto de que a atuação no campo ético é práxis política em constante dinamismo e problematização, da utilização de uma abordagem metodológica estruturalista, na qual cada elemento dá significado e é, por sua vez, significado pelos demais, e da definição de quatro grandes dimensões de atuação no Policy Cycle, buscamos apontar diferentes efeitos sistêmicos e de estrutura da operacionalização do Sistema de Gestão da Ética do Poder Executivo Federal (SGEPEF), com seu marco legal e temporal em crescente institucionalização e legitimação. Concluímos indicando novas possibilidades sistêmicas e estruturais no campo ético para avanços e inovação na gestão pública, gerando, assim, ambiente de trabalho mais humanizado e saudável, com amplo desenvolvimento organizacional.Título em inglês: Structural considerations on the exercise of the presidency of the Ethics Commissions of the Ethics Management System of the Federal Executive Branch (SGEPEF)

About the detection of gravitational wave bursts

Several filtering methods for the detection of gravitational wave bursts in interferometric detectors are presented. These are simple and fast methods which can act as online triggers. All methods are compared to matched filtering with the help of a figure of merit based on the detection of supernovae signals simulated by Zwerger and Muller.Comment: 5 pages, proceedings of GWDAW99 (Roma, Dec. 1999), to appear in Int. J. Mod. Phys.

Detection of colistin resistance in Salmonella enterica using MALDIxin test on the routine MALDI Biotyper Sirius mass spectrometer

Resistance to polymyxins in most Gram-negative bacteria arises from chemical modifications to the lipid A portion of their lipopolysaccharide (LPS) mediated by chromosomally-encoded mutations or the recently discovered plasmid-encoded mcr genes that have further complicated the landscape of colistin resistance. Currently, minimal inhibitory concentration (MIC) determination by broth microdilution, the gold standard for the detection of polymyxin resistance, is time consuming (24 hours) and challenging to perform in clinical and veterinatryveterinary laboratories. Here we present the use of the MALDIxin to detect colistin resistant Salmonella enterica using the MALDxin test on the routine matrix-assisted laser desorption ionization (MALDI) Biotyper Sirius system

An efficient filter for detecting gravitational wave bursts in interferometric detectors

Typical sources of gravitational wave bursts are supernovae, for which no accurate models exist. This calls for search methods with high efficiency and robustness to be used in the data analysis of foreseen interferometric detectors. A set of such filters is designed to detect gravitational wave burst signals. We first present filters based on the linear fit of whitened data to short straight lines in a given time window and combine them in a non linear filter named ALF. We study the performances and efficiencies of these filters, with the help of a catalogue of simulated supernova signals. The ALF filter is the most performant and most efficient of all filters. Its performance reaches about 80% of the Optimal Filter performance designed for the same signals. Such a filter could be implemented as an online trigger (dedicated to detect bursts of unknown waveform) in interferometric detectors of gravitational waves