12,699 research outputs found

    Long-lived quantum memory with nuclear atomic spins

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    We propose to store non-classical states of light into the macroscopic collective nuclear spin (101810^{18} atoms) of a 3^3He vapor, using metastability exchange collisions. These collisions, commonly used to transfer orientation from the metastable state 23S_12^{3}S\_1 to the ground state state of 3^3He, can also transfer quantum correlations. This gives a possible experimental scheme to map a squeezed vacuum field state onto a nuclear spin state with very long storage times (hours).Comment: 4 page

    Commissioning of the CMS Cryogenic System After Final Installation in the Underground Cavern

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    After having served for the surface tests of the Compact Muon Solenoid (CMS) magnet, the cold box and ancillaries of the CMS helium refrigerator have been dismantled, moved and re-installed in the USC55 cavern in 2007. The full re-commissioning in the cavern has been followed by several tests of the refrigerator to confirm its nominal performance before it was used for the magnet and detector tests in 2008. During these tests the safety modes of the refrigeration system have been tested and improved. After a nine-year project both, the magnet and the refrigeration system are now ready for the CMS operation

    Probing vortices in 4He nanodroplets

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    We present static and dynamical properties of linear vortices in 4He droplets obtained from Density Functional calculations. By comparing the adsorption properties of different atomic impurities embedded in pure droplets and in droplets where a quantized vortex has been created, we suggest that Ca atoms should be the dopant of choice to detect vortices by means of spectroscopic experiments.Comment: Typeset using Revtex4, 4 pages and 2 Postscript file

    Temperature dependent characterization of optical fibres for distributed temperature sensing in hot geothermal wells

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    This study was performed in order to select a proper fibre for the application of a distributed temperature sensing system within a hot geothermal well in Iceland. Commercially available high temperature graded index fibres have been tested under in-situ temperature conditions. Experiments have been performed with four different polyimide coated fibres, a fibre with an aluminum coating and a fibre with a gold coating. To select a fibre, the relationship between attenuation, temperature, and time has been analyzed together with SEM micrographs. On the basis of these experiments, polyimide fibres have been chosen for utilisation. Further tests in ambient and inert atmosphere have been conducted with two polyimide coated fibres to set an operating temperature limit for these fibres. SEM micrographs, together with coating colour changes have been used to characterize the high temperature performance of the fibres. A novel cable design has been developed, a deployment strategy has been worked out and a suitable well for deployment has been selected.Comment: PACS: 42.81.Pa, 93.85.Fg, 47.80.Fg, 91.35.Dc, 07.20.Dt, 07.60.V

    Human Health Effects Assays

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    Discussion of the exponential increase in environmental toxicological information and an approach for organizing and using the information was presented by Lu and Wassom.1 A user\u27s guide to the Registry of Toxic Effects of Chemical Substances (RTECS) was published by NIOSH2 that defines the record layouts and describes the types of data contained in the computer tape version of the 1984 Edition of the RTECS.3 A text summarizing information on approximately 800 toxic chemicals was edited by Sittig.4 Milestone publications concerning fundamentals of toxicology with environmental applications included the works of Gentile,5 Ashby,6 Mortel mans,7 Thacker,8 and Ruppert.9 Brusick and Auletta10 discussed the developmental status of bioassays in genetic toxicology reviewed by the U. S. Environmental Protection Agency (EPA) Gene-Tox Work Groups

    Towards improved socio-economic assessments of ocean acidificationā€™s impacts

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    Ocean acidification is increasingly recognized as a component of global change that could have a wide range of impacts on marine organisms, the ecosystems they live in, and the goods and services they provide humankind. Assessment of these potential socio-economic impacts requires integrated efforts between biologists, chemists, oceanographers, economists and social scientists. But because ocean acidification is a new research area, significant knowledge gaps are preventing economists from estimating its welfare impacts. For instance, economic data on the impact of ocean acidification on significant markets such as fisheries, aquaculture and tourism are very limited (if not non-existent), and non-market valuation studies on this topic are not yet available. Our paper summarizes the current understanding of future OA impacts and sets out what further information is required for economists to assess socio-economic impacts of ocean acidification. Our aim is to provide clear directions for multidisciplinary collaborative research

    Adsorption of a PEOā€“PPOā€“PEO triblock copolymer on metal oxide surfaces with a view to reducing protein adsorption and further biofouling

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    Biomolecule adsorption is the first stage of biofouling. The aim of this work was to reduce the adsorption of proteins on stainless steel (SS) and titanium surfaces by modifying them with a poly(ethylene oxide) (PEO)ā€“poly(propylene oxide) (PPO)ā€“PEO triblock copolymer. Anchoring of the central PPO block of the copolymer is known to be favoured by hydrophobic interaction with the substratum. Therefore, the surfaces of metal oxides were first modified by self-assembly of octadecylphosphonic acid. PEOā€“PPOā€“PEO preadsorbed on the hydrophobized surfaces of titanium or SS was shown to prevent the adsorption of bovine serum albumin (BSA), fibrinogen and cytochrome C, as monitored by quartz crystal microbalance (QCM). Moreover, X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry were used to characterize the surfaces of the SS and titanium after competitive adsorption of PEOā€“PPOā€“PEO and BSA. The results show that the adsorption of BSA is well prevented on hydrophobized surfaces, in contrast to the surfaces of native metal oxides
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