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Context. The inner few au region of planet-forming disks is a complex environment. High angular resolution observations have a key role in understanding the disk structure and the dynamical processes at work. Aims. In this study we aim to characterize the mid-infrared brightness distribution of the inner disk of the young intermediate-mass star HD 163296, from VLTI/MATISSE observations. Methods. We use geometric models to fit the data. Our models include a smoothed ring, a flat disk with inner cavity, and a 2D Gaussian. The models can account for disk inclination and for azimuthal asymmetries as well. We also perform numerical hydro-dynamical simulations of the inner edge of the disk. Results. Our modeling reveals a significant brightness asymmetry in the L-band disk emission. The brightness maximum of the asymmetry is located at the NW part of the disk image, nearly at the position angle of the semimajor axis. The surface brightness ratio in the azimuthal variation is $3.5 \pm 0.2$. Comparing our result on the location of the asymmetry with other interferometric measurements, we confirm that the morphology of the $r, accepted for publication in A&A

The nature of circumstellar envelopes (CSE) around Cepheids is still a matter of debate. The physical origin of their infrared (IR) excess could be either a shell of ionized gas, or a dust envelope, or both. This study aims at constraining the geometry and the IR excess of the environment of the long-period Cepheid $\ell$ Car (P=35.5 days) at mid-IR wavelengths to understand its physical nature. We first use photometric observations in various bands and Spitzer Space Telescope spectroscopy to constrain the IR excess of $\ell$ Car. Then, we analyze the VLTI/MATISSE measurements at a specific phase of observation, in order to determine the flux contribution, the size and shape of the environment of the star in the L band. We finally test the hypothesis of a shell of ionized gas in order to model the IR excess. We report the first detection in the L band of a centro-symmetric extended emission around l Car, of about 1.7$R_\star$ in FWHM, producing an excess of about 7.0\% in this band. In the N band, there is no clear evidence for dust emission from VLTI/MATISSE correlated flux and Spitzer data. On the other side, the modeled shell of ionized gas implies a more compact CSE ($1.13\pm0.02\,R_\star$) and fainter (IR excess of 1\% in the L band). We provide new evidences for a compact CSE of $\ell$ Car and we demonstrate the capabilities of VLTI/MATISSE for determining common properties of CSEs. While the compact CSE of $\ell$ Car is probably of gaseous nature, the tested model of a shell of ionized gas is not able to simultaneously reproduce the IR excess and the interferometric observations. Further Galactic Cepheids observations with VLTI/MATISSE are necessary for determining the properties of CSEs, which may also depend on both the pulsation period and the evolutionary state of the stars., Comment: 13 pages, 8 figures, accepted in Astronomy and Astrophysics

The durability of commercial airplane structures is strongly influenced by build quality and the extent to which assembly processes can be controlled such that the fatigue quality is consistent with that assumed in the design throughout the production life of airplane programs. New developments in assembly technology and the continual quest for manufacturing cost reductions, as well as rising production rate pressures are translating into new, often non-traditional parts and build processes being applied to commercial airplane products. This technological evolution can only take place by exercising close coordination between the structural and manufacturing engineering functions in planning, evaluating, and bringing these parts and processes safely into production. Described in this paper are some of the new processes being used at Boeing Commercial Airplanes to produce metallic and hybrid (composite + metal) assemblies for large commercial transports, viewed from a broad structural engineering perspective. The discussion focuses on two specific mechanical joining technology thrusts: (1) One-up assembly (OUA) and process automation, and (2) assembly using pre-drilled holes at the part fabrication (detail) level. A number of case studies are outlined and considerations such as process selection, control, and qualification, and fatigue characterization are highlighted. This includes a discussion of the trade-offs in fatigue capability between traditional and new methods, including some quality issues that can arise with the new approaches.

Increasingly broader application of composite materials in commercial airplane primary structure has led to a renewed, more in-depth assessment of the effect composite elements in mechanical joints have on the durability of the metal structure to which they are mated. Thermal stresses, clamp-up loss due to composite creep, composite joint properties, and lightning and electrical grounding effects have been found to be some of the parameters most significantly affecting or limiting the fatigue performance of the metallic constituents within these hybrid joints, influencing the way joint design and analysis are approached.

Regulating risks in the face of scientific uncertainty poses a particular challenge to policy-makers. Such problems are amplified when decisions are taken in a multi-level framework of supranational governance. The genetically modified organism (GMO) regulation in the European Union constitutes an especially salient issue of risk governance in a multi-lateral arena, as the topic is politically highly visible and decision-making is slow and contested. Furthermore, as authority is dispersed among multiple actors, European risk governance is in need of adequate mechanisms ensuring that decision-makers justify and account for their behavior. While legitimacy aspects of GMO governance have widely been examined, accountability relations within the field of GMO risk governance have hitherto only weakly been explored. Hence, this paper analyzes the question of who can be held accountable under the complex system of supranational risk governance. This paper claims that mere adherence by actors to the regulatory procedures during the decision-making process does not necessarily imply that overall accountability can be secured, resulting in organized irresponsibility'. Although certain piecemeal accountability may exist, establishing overall accountability is complicated, precisely as a result of the complex system of interwoven rules.

Image formation with partially coherent radiation is evaluated with the Hopkins formula and then applied to x-ray microscopy. Image characteristics expected from instruments with circular and annular pupils in partially coherent conditions are considered for two-point objects and a knife-edge object. The theoretically expected values for image characteristics that are easy accessible by an experiment, such as the width of a knife edge, are given for various x-ray microscopes.

The IMaX Team IMaX is the Imaging Magnetograph eXperiment, an instrument part of the payload of SUNRISE, a stratospheric balloon mission in Antarctica. It is also the precursor of the Visible Imaging Magnetograph of the future ESA Solar Orbiter mission. It is essentially a diffraction-limited imager that carries out spectropolarimetric measurements of high resolution (bandwidth of < 100 mÅ at 525.02 nm), and relates the polarimetric properties of the incoming light through a telescope with magnetic fields in the Sun, via the Zeeman effect. At the core of the instrument there are the polarization modulation components, two Liquid Crystal Variable Retarders (LCVRs). A demodulation efficiency is defined and used as the figure of merit, and it serves to find the theoretical optimum states for the LCVRs as well as to judge the quality of the pre-flight calibration of the system. This calibration and the method used to optimize the actual efficiency is explained. Also, the space qualification of the LCVRs is presented, where ellipsometry played a major role in studying the effects of radiation, vacuum and temperature in the operation of the LCVRs. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) Peerreview

COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only. In this work, it is described the Imaging Magnetograph eXperiment, IMaX, one of the three postfocal instruments of the Sunrise mission. The Sunrise project consists on a stratospheric balloon with a 1 m aperture telescope, which will fly from the Antarctica within the NASA Long Duration Balloon Program. IMaX will provide vector magnetograms of the solar surface with a spatial resolution of 70 m. This data is relevant for understanding how the magnetic fields emerge in the solar surface, how they couple the photospheric base with the million degrees of temperature of the solar corona and which are the processes that are responsible of the generation of such an immense temperatures. To meet this goal IMaX should work as a high sensitivity polarimeter, high resolution spectrometer and a near diffraction limited imager. Liquid Crystal Variable Retarders will be used as polarization modulators taking advantage of the optical retardation induced by application of low electric fields and avoiding mechanical mechanisms. Therefore, the interest of these devices for aerospace applications is envisaged. The spectral resolution required will be achieved by using a LiNbO3 Fabry-Perot etalon in double pass configuration as spectral filter before the two CCDs detectors. As well phase-diversity techniques will be implemented in order to improve the image quality. Nowadays, IMaX project is in the detailed design phase before fabrication, integration, assembly and verification. This paper briefly describes the current status of the instrument and the technical solutions developed to fulfil the scientific requirements. Peerreview

13 pages, 8 figures.-- Published in: "Optical, Infrared, and Millimeter Space Telescopes" [Section: Solar], edited by John C. Mather.-- Contributed to the conference with same title, Glasgow, Jun 21, 2004., Final full-text version available Open Access at: http://www.iaa.es/~jti/publications/SPIE2Valentin.pdf, The SUNRISE balloon project is a high-resolution mission to study solar magnetic fields able to resolve the critical scale of 100 km in the solar photosphere, or about one photon mean free path. The Imaging Magnetograph eXperiment (IMaX) is one of the three instruments that will fly in the balloon and will receive light from the 1m aperture telescope of the mission. IMaX should take advantage of the 15 days of uninterrupted solar observations and the exceptional resolution to help clarifying our understanding of thesmall-scale magnetic concentrations that pervade the solar surface. For this, IMaX should act as a diffraction limited imager able to carry out spectroscopic analysis with resolutions in the 50.000-100.000 range and capable to perform polarization measurements. The solutions adopted by the project to achieve all these three demanding goals are explained in this article. They include the use of Liquid Crystal Variable Retarders for the polarization modulation, oneLiNbO3 etalon in double pass and two modern CCD detectors that allow for the application of phase diversity techniques by slightly changing the focus of one of the CCDs., This project is funded by the Spanish Programa Nacional del Espacio under project ESP2003-07735.

The Instituto de Astrofisica de Canarias (IAC), Spain, together with the Spanish company Tecdis Displays Iberica, S.A., are developing voltage tunable optical retarders using liquid crystals as phase retarding medium. The ROCLIs are built for being used in the Imaging Magnetograph eXperiment (IMaX), which is one of the instruments aboard of the SUNRISE balloon mission (details about IMaX are described in a different paper in this session). A big advantage of using voltage tuned retarder plates is that no mechanisms are needed, which reduces significantly failure risk, weight, power and cost, aspects of particular importance in the SUNRISE balloon mission and for many future space borne applications. A set of prototypes has already been fabricated by Tecdis S.A. and is being characterized in the IAC laboratories. The purpose of these prototypes is to evaluate and demonstrate conceptually the suitability of the chosen liquid crystal for our use in IMaX. First results are very promising. In this paper we will present a full technical description of the ROCLIs for IMaX together with the laboratory test and verification results.

The description of the Imaging Magnetograph eXperiment (IMaX) is presented in this contribution. This is a magnetograph which will fly by the end of 2006 on a stratospheric balloon, together with other instruments (to be described elsewhere). Especial emphasis is put on the scientific requirements to obtain diffraction-limited visible magnetograms, on the optical design and several constraining characteristics, such as the wavelength tuning or the crosstalk between the Stokes parameters.

X-ray microscopy, in comparison to all other microscopy techniques, has the advantage that one can observe unstained thick (up to 10µm) biological specimens in their natural wet environment. If such an object is imaged by a high resolution x-ray microscope, its thickness usually exceeds the focal depth of the micro zone plate. Therefore, the object must be considered to be three-dimensional, consisting of several two-dimensional planes. On the basis of this model one can record the three-dimensional structure of a thick object by taking focal series images. This stack of images can then be processed by some suitable reconstruction algorithms to get the final result. One most important processing step in our microscopes, which are all non-confocal, is to reduce the defocused overlays of neighbouring object planes. This processing step requires that the wave propagation in the x-ray microscope can be described by linear system theory [1]. This means that it is allowed to neglect multiple scattering within the object or else that the first Born approximation can be applied. Therefore, the validity of the first Born approximation for x-ray microscopy experiments has to be investigated.

A Biological X-ray Microscopy Resource Center is planned to be built at the Advanced Light Source (ALS) in Berkeley. The first instrument will be the High Resolution Zone Plate Microscope (XM-1) installed at the bending magnet beam line 6.12. It will be operational in August 1994. The optical setup of this x-ray microscope is analog to a conventional visible light microscope using critical illumination (Fig. 1). Fresnel zone plates are used for both condenser and high resolution objective. The condenser zone plate illuminates the sample, and at the same time, in combination with a pinhole, acts as a monochromator providing quasi monochromatic illumination. The high resolution objective zone plate is used to create an enlarged image of the sample on a back-illuminated CCD detector. Exposure times for images with 1000 by 1000 pixels are expected to be a few seconds. In order to permit examination of the sample before and after the x-ray imaging, the design of our instrument includes two visiblelight microscopes.

In Zusammarbeit mit der IBM Basel (Dr. M. Favre) wurde ein allgemein gehaltenes, ubiquitar einsetzbares Computerprogrammsystem entwickelt (FORTRAN, overlay, 124k) und fur Daten aus der Cytologie, Kolposkopie und Histopathologie adaptiert.

Observing a thick object by a x-ray microscope with a high spatial resolution, only a thin plane of this object will be in focus; the other object planes are defocused. In-creasing the depth of field by decreasing the aperture results in a reduced spatial resolution. The conflicting requirements for high spatial resolution and large depth of field are a fundamental problem in imaging microscopy. Therefore, the extension of depth of focus by digital image processing is of interest, especially in high resolution microscopy. In this paper, the local variance weighted averaging (LVWA) method, developed by S. A. Sugimoto and Y. Ichioka /1/ and its application at the Gottingen x-ray microscope is presented.

Since the Swiss Gynecological Society suggests that cervical smears be taken only from patients age 25 years or over, we have investigated the validity of an age limitation. Analyzing the patients at our dysplasia clinic, the following statistics emerged: of the 4255 patients in the period 1970-1980, 897 or 21.08% were under 25 years of age; 190 or 4.46% were under 20. Of these women, 153 had or developed (cytologically at least) serious dysplasia or carcinoma in situ. On the basis of the data presented and the literature we are obliged to concluded that an age limit is not medically meaningful and that every sexually active woman, regardless of age, should be accepted into the preventive examination program.

In collaboration with the IBM (Basel) a computer program was developed for the analysis of data from cytology, colposcopy and histopathology. Due to the general way of formulation the program-system is applicabel for every kind of problem in natural sciences as well as economics. It is written in FORTRAN. Until now 15 parametric and non-parametric statistical tests are available for the analysis of descriptive or analytical statistical questions. The amount of data to be analyzed is nearly unlimited. Several plot-routines incorporated in the program serve for graphical presentation of distributions of different variables, of scatter-diagrams and computed functions. The internal control of the statistical monitor including the report card-system and the syntax of the input orders (with generation of error messages) are shortly explained. In a sample of 251 random selected patients showing pathological signes of the portio uteri from the department of gynecology of the university Basel the way of working of some subroutines is demonstrated and some general principles of data-acquisition and data-management in medicine are outlined.