The Space Optical Clocks Project: Development of high-performance transportable and breadboard optical clocks and advanced subsystems

The use of ultra-precise optical clocks in space ("master clocks") will allow for a range of new applications in the fields of fundamental physics (tests of Einstein's theory of General Relativity, time and frequency metrology by means of the comparison of distant terrestrial clocks), geophysics (mapping of the gravitational potential of Earth), and astronomy (providing local oscillators for radio ranging and interferometry in space). Within the ELIPS-3 program of ESA, the "Space Optical Clocks" (SOC) project aims to install and to operate an optical lattice clock on the ISS towards the end of this decade, as a natural follow-on to the ACES mission, improving its performance by at least one order of magnitude. The payload is planned to include an optical lattice clock, as well as a frequency comb, a microwave link, and an optical link for comparisons of the ISS clock with ground clocks located in several countries and continents. Undertaking a necessary step towards optical clocks in space, the EU-FP7-SPACE-2010-1 project no. 263500 (SOC2) (2011-2015) aims at two "engineering confidence", accurate transportable lattice optical clock demonstrators having relative frequency instability below 1\times10^-15 at 1 s integration time and relative inaccuracy below 5\times10^-17. This goal performance is about 2 and 1 orders better in instability and inaccuracy, respectively, than today's best transportable clocks. The devices will be based on trapped neutral ytterbium and strontium atoms. One device will be a breadboard. The two systems will be validated in laboratory environments and their performance will be established by comparison with laboratory optical clocks and primary frequency standards. In this paper we present the project and the results achieved during the first year.Comment: Contribution to European Frequency and Time Forum 2012, Gothenburg, Swede

An H4-6 chondrite: Motta di Conti

The mineralogical and chemical compositions of meteorites from the Motta di Conti, Vercelli, Italy, shower (February 29, 1868) have been determined. Microprobe analyses of olivine (Fa19.6) and orthopyroxene (Fs17.8) and the bulk chemical composition, particularly the ratios of SiO2/MgO (1.50), Fe°/Ni° (11.03), Fetotal/SiO2 (0.81), Fe°/Fetotal(0.70)and the content of Fetotal (28.60%) classify the meteorite as an H-group chondrite. The percentage of total metallic nickel-iron (22.06 percent) is somewhat higher than the average in H-group chondrites. The texture of our stone shows evidence of metamorphism. The integration between matrix and chondrules is advanced and may suggest a high petrographic grade, but the identification of several microscopic features (e.g. small grains of monoclinic twinned pyroxene, FeNi-FeS intergrowths, globules and mosaic) leads to the conclusion that a variety of petrographic types (4-6) are present. Metamorphic equilibration in chondrites is discussed and a preliminary hypothesis for H4-6 chondrites is suggested

Novel Chlamydia species isolated from snakes are temperature-sensitive and exhibit decreased susceptibility to azithromycin.

Chlamydia species have recently been recognized as emerging pathogens in snakes. However, isolation of novel snake chlamydiae is critical and their growth characteristics are largely unknown. In this study, two novel chlamydial species are described: Chlamydia serpentis and Chlamydia poikilothermis, isolated after attempts on 23 cloacal and choanal swabs from 18 PCR-positive captive snakes originating from different Swiss snake collections. Isolation success, growth curve and infectivity rates over a 48-hour time period were dependent on temperature (37 °C for C. serpentis, 28 °C for C. poikilothermis). C. serpentis and C. poikilothermis were sensitive to tetracycline and moxifloxacin during evaluation by in vitro antibiotic susceptibility assay but intermediate to resistant (2-4 μg/ml) to azithromycin. Whole genome sequencing of the isolates provided proof of the novel species status, and gives insights into the evolution of these branches of genus Chlamydia

Activity of synthetic peptides against Chlamydia.

The in vitro activity of six synthetic peptides against 36 strains of Chlamydia from different origins was investigated. Clavanin MO proved to be the most active peptide, reducing the inclusion number of all Chlamydia strains from 8 different species tested by 6550% at 10 \ub5g.ml-1 . Mastoparan L showed an equal activity against C. trachomatis, C. pneumoniae, C. suis and C. muridarum, but did not exert any inhibitory effect against C. psittaci, C. pecorum, C. abortus and C. avium even at 80 \ub5g.ml-1 . These data suggest that clavanin MO could be a promising compound in the prevention and treatment of chlamydial infections. This article is protected by copyright. All rights reserved