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TNO Science and Industry has designed and is currently developing the Basic Angle Monitoring Opto-Mechanical Assembly (BAM OMA) [1], which is part of the GAIA spacecraft. In GAIA two telescopes mounted on a slowly spinning satellite will measure the position of the stars with an accuracy much higher as ever done before. Crucial in the system is that the relative angle between the two telescopes should remain stable in the μrad range. The GAIA BAM-OMA system is equipped with two off-axis parabolic mirrors that have to be polished to a high shape accuracy.

In this work we report on micromechanically tunable Fabry-Perot filter concepts for wavelength division multiplexing (WDM) systems. The optical resonator is designed for a cavity length around 30mum in order to increase the filter selectivity while relaxing the demands on the required mirror reflectance. The introduction of micromechanical actuators, utilizing electrothermal and electrostatic principles, allows wavelength tuning of the filter over a range of more than 40nm in the 1.55mum wavelength regime. The movable Bragg mirror, designed as suspended membrane and fabricated with an InP bulk-micromachining technology, consists of a molecular beam epitaxy-grown InAlGaAs quarter-wavelength multilayer stack. The influence of micromechanical actuation and the effect of intrinsic mechanical stress on the mirror deformation has been investigated systematically to optimize the optical filter performance. Filter losses induced by the light absorption within the epitaxial Bragg mirror have been minimized using a highly doped InGaAs/InAlAs composition. Furthermore, low-loss Fabry-Perot filters have been fabricated using InAlGaAs/InAlAs Bragg mirrors. The measured full-width at half-maximum (FWHM) is 0.24nm and a filter insertion loss of 2.8dB has been observed. The FWHM is kept below 0.35nm over an entire tuning range of 40nm for an actuation power of 1.3mW. The bulk-micromachining technology presented here is open for the future development of WDM components, e.g. tunable receivers or laser diodes.

It is assumed that the mental representation of the causal structure of environmental risks, i.e., the type of cause and the type of potential consequence, determines which sort of action tendencies are formed. We propose a model of risk evaluation that includes consequentialist and deontological judgments as well as specific emotions as mediators of action tendencies. Four hundred participants took part in an experiment which presented scenario information about environmental risks. The scenarios differed with respect to (a) causation (human vs. natural cause; single vs. aggregate causation), (b) consequence (harm to self vs. harm to other people vs. harm to nature), and (c) geographical distance (proximate vs. distant). Participants indicated how much they preferred each of 31 prospective behaviors. Factor analyses yielded five types of action tendencies: help, aggression, escape, political action, and self-focus. The causal structure of the risks was systematically r elated to action tendencies, e.g., environmental risks that are caused by humans, and in particular those caused by a single human agent, elicit aggressive action tendencies. The findings confirm that the perceived causal structure of a specific risk determines whether the focus is upon consequentialist or deontological judgments, which, in turn, elicit specific types of action tendency, mediated by emotions.

The associations among daily counts of intrauterine mortality and pollutant concentrations (NO2, SO2, CO, O3, and particulate matter (3/4)10 microm) were investigated for the period ranging from January 1991 to December 1992 in the city of São Paulo, Brazil. We used Poisson regression techniques, adjusted for season and weather. The association between intrauterine mortality and air pollution was strong for NO2 (coefficient = 0.0013/ microg/m3; p