CODEX, a high resolution, super-stable spectrograph to be fed by the E-ELT, the most powerful telescope ever conceived, will for the first time provide the possibility of directly measuring the ...change of the expansion rate of the Universe with time and much more, from the variability of fundamental constants to the search for other earths. A study for the implementation at the VLT of a precursor of CODEX, dubbed ESPRESSO, is presently carried out by a collaboration including ESO, IAC, INAF, IoA Cambridge and Observatoire de Geneve. The present talk is focused on the cosmological aspects of the experiment.
The adaptive optics MACAO has been implemented in 6 focii of the VLT
observatory, in three different flavors. We present in this paper the results
obtained during the commissioning of the last of ...these units, MACAO-CRIRES.
CRIRES is a high-resolution spectrograph, which efficiency will be improved by
a factor two at least for point-sources observations with a NGS brighter than
R=15. During the commissioning, Strehl exceeding 60% have been observed with
fair seeing conditions, and a general description of the performance of this
curvature adaptive optics system is done.
Astron.Nachr. 88 (2006) 789-811 We describe and summarize the optical challenges for future instrumentation
for Extremely Large Telescopes (ELTs). Knowing the complex instrumental
requirements is ...crucial for the successful design of 30-60m aperture
telescopes. After all, the success of ELTs will heavily rely on its
instrumentation and this, in turn, will depend on the ability to produce large
and ultra-precise optical components like light-weight mirrors, aspheric
lenses, segmented filters, and large gratings. New materials and manufacturing
processes are currently under study, both at research institutes and in
industry. In the present paper, we report on its progress with particular
emphasize on volume-phase-holographic gratings, photochromic materials,
sintered silicon-carbide mirrors, ion-beam figuring, ultra-precision surfaces,
and free-form optics. All are promising technologies opening new degrees of
freedom to optical designers. New optronic-mechanical systems will enable
efficient use of the very large focal planes. We also provide exploratory
descriptions of "old" and "new" optical technologies together with suggestions
to instrument designers to overcome some of the challenges placed by ELT
instrumentation.
The World Health Organization recommends pre-exposure prophylaxis (PrEP) for all populations at substantial risk of HIV infection, including women. However, data regarding PrEP interest among women ...is lacking, particularly in Europe. Factors associated with interest in using PrEP were assessed among women respondents to the Flash! PrEP in Europe (FPIE) survey. This community-based cross-sectional study, conducted in 12 European countries, aimed to assess PrEP knowledge and interest. "High objective risk" (HOR) was assessed using established risk criteria following EACS and CDC guidelines. Factors associated with interest in using PrEP were assessed in univariable and multivariable logistic regression models. Among 678 women, 12.5% (n = 85) were considered at HOR, 46.8% (n = 317) indicated prior PrEP knowledge and 18.0% (n = 122) reported interest in using PrEP. Among women at HOR, 40.0% (n = 34) were interested in PrEP. Factors significantly associated with PrEP interest in the final multivariable model were: younger age (18-29 years) (aOR 1.9195CI: 1.07; 3.41), bad self-perceived financial status (1.841.09; 3.11), migrant status (south to north) (2.871.05; 7.89), single or dating relationship status (1.931.23; 3.03), sexual abuse history (1.861.17; 2.97), "rather high"/ "high" self-perceived HIV risk (3.211.32; 7.81), and HOR (2.491.42; 4.35). These results show that women at HOR and those who perceived themselves to be at high risk are interested in using PrEP. There is a critical need for targeted information and improved access to PrEP to increase uptake of this HIV prevention tool to meet PrEP interest among women.
As they enter mitosis, animal cells undergo profound actin-dependent changes in shape to become round. Here we identify the Cdk1 substrate, Ect2, as a central regulator of mitotic rounding, thus ...uncovering a link between the cell-cycle machinery that drives mitotic entry and its accompanying actin remodeling. Ect2 is a RhoGEF that plays a well-established role in formation of the actomyosin contractile ring at mitotic exit, through the local activation of RhoA. We find that Ect2 first becomes active in prophase, when it is exported from the nucleus into the cytoplasm, activating RhoA to induce the formation of a mechanically stiff and rounded metaphase cortex. Then, at anaphase, binding to RacGAP1 at the spindle midzone repositions Ect2 to induce local actomyosin ring formation. Ect2 localization therefore defines the stage-specific changes in actin cortex organization critical for accurate cell division.
► Ect2 drives dynamic changes in cell shape throughout mitosis ► Ect2 induces actin-dependent changes in cortical mechanics at mitotic onset ► Ect2's distinct functions are achieved through changes in subcellular localization ► Actin remodeling for animal cell division begins at mitotic entry
Cell division is accompanied by dramatic changes in cell shape, which Matthews et al. show are regulated by the Cdk1 substrate Ect2. At mitotic onset, Ect2 leaves the nucleus to activate RhoA and cortical actomyosin, driving mitotic rounding. It is then repositioned at mitotic exit to drive actomyosin ring formation.
In this paper we present the final design and the status report of the MAD module that will be installed at one of the VLT unit telescope in Paranal to perform on-sky observations. MAD is a prototype ...MCAO system performing wide field of view (FoV) AO correction over 2 arcmin on the sky by using bright (m/sub v/ < 14) natural guide stars (NGS). Multiconjugate adaptive optics aims at performing wide field of view atmospheric turbulence correction using many guide stars (GSs) surrounding the observed target. The light coming from the GSs is analyzed through wavefront sensors whose signals are used to reconstruct the atmospheric turbulence at the different heights which some deformable mirrors are conjugated to. The European Southern Observatory in collaboration with external research institutes is building an instrument prototype, the MCAO demonstrator (MAD), to prove on the sky the feasibility of the MCAO technique using both reconstruction approaches in the view of the future 2nd generation of the VLT instrumentation and the 100-meters telescope OWL.
The Multi Unit Spectroscopic Explorer (MUSE) is a second-generation VLT
panoramic integral-field spectrograph under preliminary design study. MUSE has
a field of 1x1 arcmin**2 sampled at 0.2x0.2 ...arcsec**2 and is assisted by the
VLT ground layer adaptive optics ESO facility using four laser guide stars. The
simultaneous spectral range is 465-930 nm, at a resolution of R~3000. MUSE
couples the discovery potential of a large imaging device to the measuring
capabilities of a high-quality spectrograph, while taking advantage of the
increased spatial resolution provided by adaptive optics. This makes MUSE a
unique and tremendously powerful instrument for discovering and characterizing
objects that lie beyond the reach of even the deepest imaging surveys. MUSE has
also a high spatial resolution mode with 7.5x7.5 arcsec**2 field of view
sampled at 25 milli-arcsec. In this mode MUSE should be able to obtain
diffraction limited data-cubes in the 600-930 nm wavelength range. Although the
MUSE design has been optimized for the study of galaxy formation and evolution,
it has a wide range of possible applications; e.g. monitoring of outer planets
atmosphere, environment of young stellar objects, super massive black holes and
active nuclei in nearby galaxies or massive spectroscopic surveys of stellar
fields in the Milky Way and nearby galaxies.
High resolution spectroscopy made an important step ahead 10 years ago, leading for example to the discovery of numerous exoplanets. But the IR did not benefit from this improvement until very ...recently. CRIRES will provide a dramatic improvement in the 1-5 micron region in this field. Adaptive optics will allow us increasing both flux and angular resolution on its spectra. This paper describes the adaptive optics of CRIRES, its main limitations, its main components, the principle of its calibration with an overview of the methods used and the very first results obtained since it is installed in the laboratory.
The adaptive optics MACAO has been implemented in 6 focii of the VLT observatory, in three different flavors. We present in this paper the results obtained during the commissioning of the last of ...these units, MACAO-CRIRES. CRIRES is a high-resolution spectrograph, which efficiency will be improved by a factor two at least for point-sources observations with a NGS brighter than R=15. During the commissioning, Strehl exceeding 60% have been observed with fair seeing conditions, and a general description of the performance of this curvature adaptive optics system is done.
Proc.SPIE Int.Soc.Opt.Eng. 4841 (2003) 1548-1561 SINFONI is an adaptive optics assisted near-infrared integral field
spectrometer for the ESO VLT. The Adaptive Optics Module (built by the ESO
...Adaptive Optics Group) is a 60-elements curvature-sensor based system, designed
for operations with natural or sodium laser guide stars. The near-infrared
integral field spectrometer SPIFFI (built by the Infrared Group of MPE)
provides simultaneous spectroscopy of 32 x 32 spatial pixels, and a spectral
resolving power of up to 3300. The adaptive optics module is in the phase of
integration; the spectrometer is presently tested in the laboratory. We provide
an overview of the project, with particular emphasis on the problems
encountered in designing and building an adaptive optics assisted spectrometer.
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