Bigot-Sazy M-A, Charlassier R, Hamilton J-Ch, Kaplan J, Zahariade G, . (2013). Self-calibration: an efficient method to control systematic effects in bolometric interferometry
. ASTRONOMY & ASTROPHYSICS, 550(A), 59.
Abstract: Context. The QUBIC collaboration is building a bolometric interferometer dedicated to the detection of B-mode polarization fluctuations in the cosmic microwave background.
Aims: We introduce a self-calibration procedure related to those used in radio-interferometry to control a wide range of instrumental systematic errors in polarization-sensitive instruments.
Methods: This procedure takes advantage of the need for measurements on redundant baselines to match each other exactly in the absence of systematic effects. For a given systematic error model, measuring each baseline independently therefore allows writing a system of nonlinear equations whose unknowns are the systematic error model parameters (gains and couplings of Jones matrices, for instance).
Results: We give the mathematical basis of the self-calibration. We implement this method numerically in the context of bolometric interferometry. We show that, for large enough arrays of horns, the nonlinear system can be solved numerically using a standard nonlinear least-squares fitting and that the accuracy achievable on systematic effects is only limited by the time spent on the calibration mode for each baseline apart from the validity of the systematic error model.
Programme: 915
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Bernard É, Friedt JM, Saintenoy A, Tolle F, Griselin M, Marlin C, . (2014). Where does a glacier end? GPR measurements to identify the limits between valley slopes and actual glacier body. Application to the Austre Lovénbreen, Spitsbergen . International Journal of Applied Earth Observation and Geoinformation, 27, Part A(A), 100–108.
Keywords: Ground penetrating Radar, Glacier limit, Arctic, Spitsbergen, Polar glacier,
Programme: 1108,1111
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. (2015). Winter use of sea ice and ocean water mass habitat by southern elephant seals: The length and breadth of the mystery
. Prog. Oceanogr., 137(A), 52–68.
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. (2013). Quality Assessment of the First Measurements of Tropospheric Water Vapor and Temperature by the HAMSTRAD Radiometer Over Concordia Station, Antarctica
. 0196-2892, PP(99), 1–23.
Keywords: Extraterrestrial measurements, Instruments, Microwave radiometry, Ocean temperature, Temperature measurement, Terrestrial atmosphere, Water, Antarctica, atmospheric measurements, humidity measurements, least squares methods, microwave measurements, microwave radiometry, temperature measurements, time series analysis,
Programme: 910,1013
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. (2022). Integument carotenoid-based colouration reflects contamination to perfluoroalkyl substances, but not mercury, in arctic black-legged kittiwakes (Vol. 10).
Abstract: Anthropogenic activities are introducing multiple chemical contaminants into ecosystems that act as stressors for wildlife. Perfluoroalkyl substances (PFAS) and mercury (Hg) are two relevant contaminants that may cause detrimental effects on the fitness of many aquatic organisms. However, there is a lack of information on their impact on the expression of secondary sexual signals that animals use for mate choice. We have explored the correlations between integument carotenoid-based colourations, blood levels of carotenoids, and blood levels of seven PFAS and of total Hg (THg) in 50 adult male black-legged kittiwakes (Rissa tridactyla) from the Norwegian Arctic during the pre-laying period, while controlling for other colouration influencing variables such as testosterone and body condition. Kittiwakes with elevated blood concentrations of PFAS (PFOSlin, PFNA, PFDcA, PFUnA, or PFDoA) had less chromatic but brighter bills, and brighter gape and tongue; PFOSlin was the pollutant with the strongest association with bill colourations. Conversely, plasma testosterone was the only significant correlate of hue and chroma of both gape and tongue, and of hue of the bill. Kittiwakes with higher concentrations of any PFAS, but not of THg, tended to have significantly higher plasma concentrations of the carotenoids astaxanthin, zeaxanthin, lutein, and cryptoxanthin. Our work provides the first correlative evidence that PFAS exposure might interfere with the carotenoid metabolism and the expression of integument carotenoid-based colourations in a free-living bird species. This outcome may be a direct effect of PFAS exposure or be indirectly caused by components of diet that also correlate with elevated PFAS concentrations (e.g., proteins). It also suggests that there might be no additive effect of THg co-exposure with PFAS on the expression of colourations. These results call for further work on the possible interference of PFAS with the expression of colourations used in mate choice.
Programme: 330
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Kenyon, S. L.; Lawrence, J. S.; Ashley, M. C. B.; Storey, J. W. V.; Tokovinin, A.; Fossat, E. (2006). Atmospheric Scintillation at Dome C, Antarctica: Implications for Photometryand Astrometry. The Publications of the Astronomical Society of the Pacific, 118(944), 924–932.
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. (2014). (Vol. 126).
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Sims, G., M. C. B. Ashley, X. Cui, J. R. Everett, L. Feng, X. Gong, S. Hengst, Z. Hu, C. Kulesa, J. S. Lawrence, D. M. Luong-Van, P. Ricaud, Z. Shang, J. W. V. Storey, L. Wang, H. Yang, J. Yang, X. Zhou, Z. Zhu. (2012). Precipitable Water Vapor above Dome A, Antarctica, Determined from Diffuse Optical Sky Spectra. Publications of the Astronomical Society of the Pacific, 124(911), 74–83.
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Krinner G. & Genthon C. (1998). GCM simulations of the Last Glacial Maximum surface climate of Greenland and Antarctica. Climate dynamics, 14(9), 741–758.
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Bondar T N, Golovkov V P, . (1992). IZMIRAN Candidate Models for DGRF 1985, IGRF 1990 and a Secular Variation Forecast Model for the 1990-1995 Period
. Journal of geomagnetism and geoelectricity, 44(9), 709–717.
Abstract: Two candidate main field models for 1985 and 1990 as well as a forecast for the secular variation are represented as a series of spherical harmonic coefficients up to n=m=10 and n=m=8, respectively. IZMSV, US/UK, USGS forecasting models are compared with extrapolated secular variation observations and with one another. The IZMSV and the USGS are shown to agree best.
Programme: 139
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