| 1. |
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| 2. |
- Niemi, MEK, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 3. |
- Kanai, M, et al.
(författare)
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- 2023
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swepub:Mat__t
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| 4. |
- Schael, S, et al.
(författare)
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Precision electroweak measurements on the Z resonance
- 2006
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Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
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Forskningsöversikt (refereegranskat)abstract
- We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
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| 5. |
- Thomas, HS, et al.
(författare)
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- 2019
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swepub:Mat__t
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| 6. |
- Acharya, B. S., et al.
(författare)
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Introducing the CTA concept
- 2013
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Ingår i: Astroparticle physics. - : Elsevier BV. - 0927-6505 .- 1873-2852. ; 43, s. 3-18
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The Cherenkov Telescope Array (CTA) is a new observatory for very high-energy (VHE) gamma rays. CTA has ambitions science goals, for which it is necessary to achieve full-sky coverage, to improve the sensitivity by about an order of magnitude, to span about four decades of energy, from a few tens of GeV to above 100 TeV with enhanced angular and energy resolutions over existing VHE gamma-ray observatories. An international collaboration has formed with more than 1000 members from 27 countries in Europe, Asia, Africa and North and South America. In 2010 the CTA Consortium completed a Design Study and started a three-year Preparatory Phase which leads to production readiness of CTA in 2014. In this paper we introduce the science goals and the concept of CTA, and provide an overview of the project. (C) 2013 Elsevier B.V. All rights reserved.
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| 7. |
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| 8. |
- Actis, M., et al.
(författare)
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Design concepts for the Cherenkov Telescope Array CTA : an advanced facility for ground-based high-energy gamma-ray astronomy
- 2011
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Ingår i: Experimental astronomy. - : Springer. - 0922-6435 .- 1572-9508. ; 32:3, s. 193-316
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Tidskriftsartikel (refereegranskat)abstract
- Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA.
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| 9. |
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| 10. |
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| 11. |
- Abreu, P., et al.
(författare)
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Measurement of the gluon fragmentation function and a comparison of the scaling violation in gluon and quark jets
- 2000
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 13:4, s. 573-589
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Tidskriftsartikel (refereegranskat)abstract
- The fragmentation functions of quarks and gluons are measured in various three-jet topologies in Z decays from the full data set collected with the DELPHI detector at the Z resonance between 1992 and 995. The results at different values of transverse momentum-like scales are compared. A parameterization of the quark and gluon fragmentation functions at a fixed reference scale is given. The quark and gluon fragmentation functions show the predicted pattern of scaling violations. The scaling violation for quark jets as a function of a transverse momentum-like scale is in a good agreement with that observed in lower energy e+e- annihilation experiments. For gluon jets it appears to be significantly stronger. The scale dependences of the gluon and quark fragmentation functions agree with the prediction of the DGLAP evolution equations from which the colour factor ratio CA/CF is measured to be: CA/CF = 2.26 ± 0.09stat. ± 0.06sys. ± 0.12clus.,scale..
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| 12. |
- Abreu, P., et al.
(författare)
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Study of dimuon production in photon-photon collisions and measurement of QED photon structure functions at LEP
- 2001
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 19:1, s. 15-28
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Tidskriftsartikel (refereegranskat)abstract
- Muon pair production in the process e+e- → e+e- μ+μ- is studied using the data taken at LEP1 (√s ≃ mz) with the DELPHI detector during the years 1992-1995. The corresponding integrated luminosity is 138.5 pb-1. The QED predictions have been tested over the whole Q2 range accessible at LEP1 (from several GeV2/c4 to several hundred GeV2/c4) by comparing experimental distributions with distributions resulting from Monte Carlo simulations using various generators. Selected events are used to extract the leptonic photon structure function Fγ 2. Azimuthal correlations are used to obtain information on additional structure functions, Fγ A and Fγ B, which originate from interference terms of the scattering amplitudes. The measured ratios Fγ A/Fγ 2 and FγB/Fγ 2 are significantly different from zero and consistent with QED predictions.
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| 13. |
- Ageron, M., et al.
(författare)
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ANTARES : The first undersea neutrino telescope
- 2011
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 656:1, s. 11-38
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Tidskriftsartikel (refereegranskat)abstract
- The ANTARES Neutrino Telescope was completed in May 2008 and is the first operational Neutrino Telescope in the Mediterranean Sea. The main purpose of the detector is to perform neutrino astronomy and the apparatus also offers facilities for marine and Earth sciences. This paper describes the design, the construction and the installation of the telescope in the deep sea, offshore from Toulon in France. An illustration of the detector performance is given. (C) 2011 Elsevier B.V. All rights reserved.
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| 14. |
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| 15. |
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| 16. |
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| 17. |
- Abe, O, et al.
(författare)
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Effects of chemotherapy and hormonal therapy for early breast cancer on recurrence and 15-year survival: an overview of the randomised trials
- 2005
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Ingår i: The Lancet. - 1474-547X. ; 365:9472, s. 1687-1717
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Tidskriftsartikel (refereegranskat)abstract
- Background Quinquennial overviews (1985-2000) of the randomised trials in early breast cancer have assessed the 5-year and 10-year effects of various systemic adjuvant therapies on breast cancer recurrence and survival. Here, we report the 10-year and 15-year effects. Methods Collaborative meta-analyses were undertaken of 194 unconfounded randomised trials of adjuvant chemotherapy or hormonal therapy that began by 1995. Many trials involved CMF (cyclophosphamide, methotrexate, fluorouracil), anthracycline-based combinations such as FAC (fluorouracil, doxombicin, cyclophosphamide) or FEC (fluorouracil, epirubicin, cyclophosphamide), tamoxifen, or ovarian suppression: none involved taxanes, trastuzumab, raloxifene, or modem aromatase inhibitors. Findings Allocation to about 6 months of anthracycline-based polychemotherapy (eg, with FAC or FEC) reduces the annual breast cancer death rate by about 38% (SE 5) for women younger than 50 years of age when diagnosed and by about 20% (SE 4) for those of age 50-69 years when diagnosed, largely irrespective of the use of tamoxifen and of oestrogen receptor (ER) status, nodal status, or other tumour characteristics. Such regimens are significantly (2p=0 . 0001 for recurrence, 2p<0 . 00001 for breast cancer mortality) more effective than CMF chemotherapy. Few women of age 70 years or older entered these chemotherapy trials. For ER-positive disease only, allocation to about 5 years of adjuvant tamoxifen reduces the annual breast cancer death rate by 31% (SE 3), largely irrespective of the use of chemotherapy and of age (<50, 50-69, &GE; 70 years), progesterone receptor status, or other tumour characteristics. 5 years is significantly (2p<0 . 00001 for recurrence, 2p=0 . 01 for breast cancer mortality) more effective than just 1-2 years of tamoxifen. For ER-positive tumours, the annual breast cancer mortality rates are similar during years 0-4 and 5-14, as are the proportional reductions in them by 5 years of tamoxifen, so the cumulative reduction in mortality is more than twice as big at 15 years as at 5 years after diagnosis. These results combine six meta-analyses: anthracycline-based versus no chemotherapy (8000 women); CMF-based versus no chemotherapy (14 000); anthracycline-based versus CMF-based chemotherapy (14 000); about 5 years of tamoxifen versus none (15 000); about 1-2 years of tamoxifen versus none (33 000); and about 5 years versus 1-2 years of tamoxifen (18 000). Finally, allocation to ovarian ablation or suppression (8000 women) also significantly reduces breast cancer mortality, but appears to do so only in the absence of other systemic treatments. For middle-aged women with ER-positive disease (the commonest type of breast cancer), the breast cancer mortality rate throughout the next 15 years would be approximately halved by 6 months of anthracycline-based chemotherapy (with a combination such as FAC or FEC) followed by 5 years of adjuvant tamoxifen. For, if mortality reductions of 38% (age <50 years) and 20% (age 50-69 years) from such chemotherapy were followed by a further reduction of 31% from tamoxifen in the risks that remain, the final mortality reductions would be 57% and 45%, respectively (and, the trial results could well have been somewhat stronger if there had been full compliance with the allocated treatments). Overall survival would be comparably improved, since these treatments have relatively small effects on mortality from the aggregate of all other causes. Interpretation Some of the widely practicable adjuvant drug treatments that were being tested in the 1980s, which substantially reduced 5-year recurrence rates (but had somewhat less effect on 5-year mortality rates), also substantially reduce 15-year mortality rates. Further improvements in long-term survival could well be available from newer drugs, or better use of older drugs.
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| 18. |
- Aguilar, J. A., et al.
(författare)
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First results of the instrumentation line for the deep-sea ANTARES neutrino telescope
- 2006
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Ingår i: Astroparticle physics. - : Elsevier. - 0927-6505 .- 1873-2852. ; 26:4-5, s. 314-324
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Tidskriftsartikel (refereegranskat)abstract
- In 2005, the ANTARES Collaboration deployed and operated at a depth of 2500 m a so-called Mini Instrumentation Line equipped with Optical Modules (MILOM) at the ANTARES site. The various data acquired during the continuous operation from April to December 2005 of the MILOM confirm the satisfactory performance of the Optical Modules, their front-end electronics and readout system. as well as the calibration devices of the detector. The in situ measurement of the Optical Module time response yields a resolution better than 0.5 ns. The performance of the acoustic positioning system, which enables the spatial reconstruction of the ANTARES detector with a precision of about 10 cm, is verified. These results demonstrate that with the full ANTARES neutrino telescope the design angular resolution of better than 0.3 degrees can be realistically achieved.
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| 19. |
- Aguilar, J. A., et al.
(författare)
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The data acquisition system for the ANTARES neutrino telescope
- 2007
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 570:1, s. 107-116
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Tidskriftsartikel (refereegranskat)abstract
- The ANTARES neutrino telescope is being constructed in the Mediterranean Sea. It consists of a large three-dimensional array of photo-multiplier tubes. The data acquisition system of the detector takes care of the digitisation of the photo-multiplier tube signals, data transport, data filtering, and data storage. The detector is operated using a control program interfaced with all elements. The design and the implementation of the data acquisition system are described. (c) 2006 Elsevier B.V. All rights reserved.
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| 20. |
- Ageron, M., et al.
(författare)
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Studies of a full-scale mechanical prototype line for the ANTARES neutrino telescope and tests of a prototype instrument for deep-sea acoustic measurements
- 2007
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 581:3, s. 695-708
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Tidskriftsartikel (refereegranskat)abstract
- full-scale mechanical prototype line was deployed to a depth of 2500 m to test the leak tightness of the electronics containers and the pressure-resistant properties of an electromechanical cable under evaluation for use in the ANTARES deep-sea neutrino telescope. During a month-long immersion study, line parameter data were taken using miniature autonomous data loggers and shore-based optical time domain reflectometry. Details of the mechanical prototype line, the electromechanical cable and data acquisition are presented. Data taken during the immersion study revealed deficiencies in the pressure resistance of the electromechanical cable terminations at the entry points to the electronics containers. The improvements to the termination, which have been integrated into subsequent detection lines, are discussed. The line also allowed deep-sea acoustic measurements with a prototype hydrophone system. The technical setup of this system is described, and the first results of the data analysis are presented. (c) 2007 Elsevier B.V. All rights reserved.
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| 21. |
- Ageron, M., et al.
(författare)
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The ANTARES optical beacon system
- 2007
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 578:3, s. 498-509
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Tidskriftsartikel (refereegranskat)abstract
- ANTARES is a neutrino telescope being deployed in the Mediterranean Sea. It consists of a three-dimensional array of photomultiplier tubes that can detect the Cherenkov light induced by charged particles produced in the interactions of neutrinos with the surrounding medium. High angular resolution can be achieved, in particular, when a muon is produced, provided that the Cherenkov photons are detected with sufficient timing precision. Considerations of the intrinsic time uncertainties stemming from the transit time spread in the photomultiplier tubes and the mechanism of transmission of light in sea water lead to the conclusion that a relative time accuracy of the order of 0.5 ns is desirable. Accordingly, different time calibration systems have been developed for the ANTARES telescope. In this article, a system based on Optical Beacons, a set of external and well-controlled pulsed light sources located throughout the detector, is described. This calibration system takes into account the optical properties of sea water, which is used as the detection volume of the ANTARES telescope. The design, tests, construction and first results of the two types of beacons, LED and laser-based, are presented. (C) 2007 Elsevier B.V. All rights reserved.
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| 22. |
- Fernandez, D., et al.
(författare)
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Experimental study of high-energy fission and quasi-fission dynamics with fusion-induced fission reactions at VAMOS(++)
- 2023
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Ingår i: 15TH INTERNATIONAL CONFERENCE ON NUCLEAR DATA FOR SCIENCE AND TECHNOLOGY, ND2022. - 2100-014X. ; 284
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Konferensbidrag (refereegranskat)abstract
- During the last decade, the use of inverse kinematics in the experimental study of fission is bringing a wealth of new observables obtained in single measurements, allowing their analysis and their correlations. An ongoing application of this technique is the basis of a series of experiments performed with the variable -mode, large -acceptance VAMOS++ spectrometer at GANIL. A recent experiment has been focused on the survival of the nuclear structure effects at high excitation energy in fission and quasi-fission. The full isotopic identification of fragments, the fission dynamics and the ratio between the production of fragments with even and odd atomic numbers, the so-called proton even -odd effect, are shown. The latter shows a different mechanism for fission and quasi -fission that could be used to separate fission from quasi-fission.
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| 23. |
- Ramos, D., et al.
(författare)
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First Direct Measurement of Isotopic Fission-Fragment Yields of 239U
- 2019
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Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 123:9
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Tidskriftsartikel (refereegranskat)abstract
- A direct and complete measurement of isotopic fission-fragment yields of U-239 has been performed for the first time. The U-239 fissioning system was produced with an average excitation energy of 8.3 MeV in one-neutron transfer reactions between a U-239 beam and a Be-9 target at Coulomb barrier energies. The fission fragments were detected and isotopically identified using the VAMOS++ spectrometer at the GANIL facility. The measurement allows us to directly evaluate the fission models at excitation energies of fast neutrons, which are relevant for next-generation nuclear reactors. The present data, in agreement with model calculations, do not support the recently reported anomaly in the fission-fragment yields of U-239, and they confirm the persistence of spherical shell effects in the Sn region at excitation energies exceeding the fission barrier by a few mega-electron volts.
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| 24. |
- Ramos, D., et al.
(författare)
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Scission configuration of U-239 from yields and kinetic information of fission fragments
- 2020
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Ingår i: Physical Review C. - 2469-9985 .- 2469-9993. ; 101:3
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Tidskriftsartikel (refereegranskat)abstract
- The simultaneous measurement of the isotopic fission-fragment yields and fission-fragment velocities of U-239 has been performed for the first time. The U-239 fissioning system was produced in one-neutron transfer reactions between a U-238 beam at 5.88 MeV/nucleon and a Be-9 target. The combination of inverse kinematics at low energy and the use of the VAMOS + + spectrometer at the GANIL facility allows the isotopic identification of the full fission-fragment distribution and their velocity in the reference frame of the fissioning system. The proton and neutron content of the fragments at scission, their total kinetic and total excitation energy, as well as the neutron multiplicity were determined. Information from the scission point configuration is obtained from these observables and the correlation between them. The role of the octupole-deformed proton and neutron shells in the fission-fragment production is discussed.
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| 25. |
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| 26. |
- Gerotziafas, GT, et al.
(författare)
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Guidance for the Management of Patients with Vascular Disease or Cardiovascular Risk Factors and COVID-19: Position Paper from VAS-European Independent Foundation in Angiology/Vascular Medicine
- 2020
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Ingår i: Thrombosis and haemostasis. - : Georg Thieme Verlag KG. - 2567-689X .- 0340-6245. ; 120:12, s. 1597-1628
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Tidskriftsartikel (refereegranskat)abstract
- COVID-19 is also manifested with hypercoagulability, pulmonary intravascular coagulation, microangiopathy, and venous thromboembolism (VTE) or arterial thrombosis. Predisposing risk factors to severe COVID-19 are male sex, underlying cardiovascular disease, or cardiovascular risk factors including noncontrolled diabetes mellitus or arterial hypertension, obesity, and advanced age. The VAS-European Independent Foundation in Angiology/Vascular Medicine draws attention to patients with vascular disease (VD) and presents an integral strategy for the management of patients with VD or cardiovascular risk factors (VD-CVR) and COVID-19. VAS recommends (1) a COVID-19-oriented primary health care network for patients with VD-CVR for identification of patients with VD-CVR in the community and patients' education for disease symptoms, use of eHealth technology, adherence to the antithrombotic and vascular regulating treatments, and (2) close medical follow-up for efficacious control of VD progression and prompt application of physical and social distancing measures in case of new epidemic waves. For patients with VD-CVR who receive home treatment for COVID-19, VAS recommends assessment for (1) disease worsening risk and prioritized hospitalization of those at high risk and (2) VTE risk assessment and thromboprophylaxis with rivaroxaban, betrixaban, or low-molecular-weight heparin (LMWH) for those at high risk. For hospitalized patients with VD-CVR and COVID-19, VAS recommends (1) routine thromboprophylaxis with weight-adjusted intermediate doses of LMWH (unless contraindication); (2) LMWH as the drug of choice over unfractionated heparin or direct oral anticoagulants for the treatment of VTE or hypercoagulability; (3) careful evaluation of the risk for disease worsening and prompt application of targeted antiviral or convalescence treatments; (4) monitoring of D-dimer for optimization of the antithrombotic treatment; and (5) evaluation of the risk of VTE before hospital discharge using the IMPROVE-D-dimer score and prolonged post-discharge thromboprophylaxis with rivaroxaban, betrixaban, or LMWH.
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| 27. |
- Mantovani, G., et al.
(författare)
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Study of High-Energy Fission in Inverse Kinematics
- 2019
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Ingår i: IV INTERNATIONAL CONFERENCE ON NUCLEAR STRUCTURE AND DYNAMICS (NSD2019). - : EDP Sciences. - 2100-014X. - 9782759890842 ; 223
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Konferensbidrag (refereegranskat)abstract
- Fission at low excitation energy, is a process in which both macroscopic and microscopic aspects are involved. Some features in the total kinetic energy and in the N/Z distributions of the fragments, commonly associated with shell effects, came out in a series of recent experiments with high excitation energy fusion fission reactions in inverse kinematics. In the latest experiment of this campaign, a study of high-energy fission and quasi-fission between a U-238 beam and a series of light targets was carried out by using the aforementioned technique, in order to probe the role of the shell structure in these processes.
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| 28. |
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| 29. |
- Forgetta, V., et al.
(författare)
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Development of a polygenic risk score to improve screening for fracture risk: A genetic risk prediction study
- 2020
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Ingår i: PLoS medicine. - : Public Library of Science (PLoS). - 1549-1277 .- 1549-1676. ; 17:7
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Tidskriftsartikel (refereegranskat)abstract
- Background Since screening programs identify only a small proportion of the population as eligible for an intervention, genomic prediction of heritable risk factors could decrease the number needing to be screened by removing individuals at low genetic risk. We therefore tested whether a polygenic risk score for heel quantitative ultrasound speed of sound (SOS)-a heritable risk factor for osteoporotic fracture-can identify low-risk individuals who can safely be excluded from a fracture risk screening program. Methods and findings A polygenic risk score for SOS was trained and selected in 2 separate subsets of UK Biobank (comprising 341,449 and 5,335 individuals). The top-performing prediction model was termed "gSOS", and its utility in fracture risk screening was tested in 5 validation cohorts using the National Osteoporosis Guideline Group clinical guidelines (N= 10,522 eligible participants). All individuals were genome-wide genotyped and had measured fracture risk factors. Across the 5 cohorts, the average age ranged from 57 to 75 years, and 54% of studied individuals were women. The main outcomes were the sensitivity and specificity to correctly identify individuals requiring treatment with and without genetic prescreening. The reference standard was a bone mineral density (BMD)-based Fracture Risk Assessment Tool (FRAX) score. The secondary outcomes were the proportions of the screened population requiring clinical-risk-factor-based FRAX (CRF-FRAX) screening and BMD-based FRAX (BMD-FRAX) screening. gSOS was strongly correlated with measured SOS (r(2)= 23.2%, 95% CI 22.7% to 23.7%). Without genetic prescreening, guideline recommendations achieved a sensitivity and specificity for correct treatment assignment of 99.6% and 97.1%, respectively, in the validation cohorts. However, 81% of the population required CRF-FRAX tests, and 37% required BMD-FRAX tests to achieve this accuracy. Using gSOS in prescreening and limiting further assessment to those with a low gSOS resulted in small changes to the sensitivity and specificity (93.4% and 98.5%, respectively), but the proportions of individuals requiring CRF-FRAX tests and BMD-FRAX tests were reduced by 37% and 41%, respectively. Study limitations include a reliance on cohorts of predominantly European ethnicity and use of a proxy of fracture risk. Conclusions Our results suggest that the use of a polygenic risk score in fracture risk screening could decrease the number of individuals requiring screening tests, including BMD measurement, while maintaining a high sensitivity and specificity to identify individuals who should be recommended an intervention. Author summaryWhy was this study done? Osteoporosis screening identifies only a small proportion of the screened population to be eligible for intervention. The prediction of heritable risk factors using polygenic risk scores could decrease the number of screened individuals by reassuring those with low genetic risk. We investigated whether the genetic prediction of heel quantitative ultrasound speed of sound (SOS)-a heritable risk factor for osteoporotic fracture-could be incorporated into an established screening guideline to identify individuals at low risk for osteoporosis. What did the researchers do and find? Using UK Biobank, we developed a polygenic risk score (gSOS) consisting of 21,717 genetic variants that was strongly correlated with SOS ( = 23.2%). Using the National Osteoporosis Guideline Group clinical assessment guidelines in 5 validation cohorts, we estimate that reassuring individuals with a high gSOS, rather than doing further assessments, could reduce the number of clinical-risk-factor-based Fracture Risk Assessment Tool (FRAX) tests and bone-density-measurement-based FRAX tests by 37% and 41%, respectively, while maintaining a high sensitivity and specificity to identify individuals who should be recommended an intervention. What do these findings mean? We show that genetic pre-screening could reduce the number of screening tests needed to identify individuals at risk of osteoporotic fractures. Therefore, the potential exists to improve the efficiency of osteoporosis screening programs without large losses in sensitivity or specificity to identify individuals who should receive an intervention. Further translational studies are needed to test the clinical applications of this polygenic risk score; however, our work shows how such scores could be tested in the clinic.
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| 30. |
- Ademuyiwa, Adesoji O., et al.
(författare)
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Determinants of morbidity and mortality following emergency abdominal surgery in children in low-income and middle-income countries
- 2016
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Ingår i: BMJ Global Health. - : BMJ Publishing Group Ltd. - 2059-7908. ; 1:4
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Tidskriftsartikel (refereegranskat)abstract
- Background: Child health is a key priority on the global health agenda, yet the provision of essential and emergency surgery in children is patchy in resource-poor regions. This study was aimed to determine the mortality risk for emergency abdominal paediatric surgery in low-income countries globally.Methods: Multicentre, international, prospective, cohort study. Self-selected surgical units performing emergency abdominal surgery submitted prespecified data for consecutive children aged <16 years during a 2-week period between July and December 2014. The United Nation's Human Development Index (HDI) was used to stratify countries. The main outcome measure was 30-day postoperative mortality, analysed by multilevel logistic regression.Results: This study included 1409 patients from 253 centres in 43 countries; 282 children were under 2 years of age. Among them, 265 (18.8%) were from low-HDI, 450 (31.9%) from middle-HDI and 694 (49.3%) from high-HDI countries. The most common operations performed were appendectomy, small bowel resection, pyloromyotomy and correction of intussusception. After adjustment for patient and hospital risk factors, child mortality at 30 days was significantly higher in low-HDI (adjusted OR 7.14 (95% CI 2.52 to 20.23), p<0.001) and middle-HDI (4.42 (1.44 to 13.56), p=0.009) countries compared with high-HDI countries, translating to 40 excess deaths per 1000 procedures performed.Conclusions: Adjusted mortality in children following emergency abdominal surgery may be as high as 7 times greater in low-HDI and middle-HDI countries compared with high-HDI countries. Effective provision of emergency essential surgery should be a key priority for global child health agendas.
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| 31. |
- Durand, M., et al.
(författare)
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An intercomparison of remote sensing river discharge estimation algorithms from measurements of river height, width, and slope
- 2016
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Ingår i: Water resources research. - 0043-1397 .- 1944-7973. ; 52:6, s. 4527-4549
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Tidskriftsartikel (refereegranskat)abstract
- The Surface Water and Ocean Topography (SWOT) satellite mission planned for launch in 2020 will map river elevations and inundated area globally for rivers >100 m wide. In advance of this launch, we here evaluated the possibility of estimating discharge in ungauged rivers using synthetic, daily remote sensing measurements derived from hydraulic models corrupted with minimal observational errors. Five discharge algorithms were evaluated, as well as the median of the five, for 19 rivers spanning a range of hydraulic and geomorphic conditions. Reliance upon a priori information, and thus applicability to truly ungauged reaches, varied among algorithms: one algorithm employed only global limits on velocity and depth, while the other algorithms relied on globally available prior estimates of discharge. We found at least one algorithm able to estimate instantaneous discharge to within 35% relative root-mean-squared error (RRMSE) on 14/16 nonbraided rivers despite out-of-bank flows, multichannel planforms, and backwater effects. Moreover, we found RRMSE was often dominated by bias; the median standard deviation of relative residuals across the 16 nonbraided rivers was only 12.5%. SWOT discharge algorithm progress is therefore encouraging, yet future efforts should consider incorporating ancillary data or multialgorithm synergy to improve results.
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| 32. |
- Grundy, Myriam M.L., et al.
(författare)
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INFOGEST inter-laboratory recommendations for assaying gastric and pancreatic lipases activities prior to in vitro digestion studies
- 2021
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Ingår i: Journal of Functional Foods. - : Elsevier BV. - 1756-4646. ; 82
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Tidskriftsartikel (refereegranskat)abstract
- In vitro digestion studies often use animal digestive enzyme extracts as substitutes of human gastric and pancreatic secretions. Pancreatin from porcine origin is thus commonly used to provide relevant pancreatic enzymes such as proteases, amylase and lipase. Rabbit gastric extracts (RGE) have been recently introduced to provide gastric lipase in addition to pepsin. Before preparing simulated gastric and pancreatic extracts with targeted enzyme activities as described in in vitro digestion protocols, it is important to determine the activities of enzyme preparations using validated methods. The purpose of this inter-laboratory study within the INFOGEST network was to test the repeatability and reproducibility of lipase assays using the pH-stat technique for measuring the activities of gastric and pancreatic lipases from various sources. Twenty-one laboratories having different pH-stat devices received the same protocol with identical batches of RGE and two pancreatin sources. Lipase assays were performed using tributyrin as a substrate and three different amounts (50, 100 and 200 µg) of each enzyme preparation. The repeatability results within individual laboratories were satisfactory with coefficients of variation (CVs) ranging from 4 to 8% regardless of the enzyme amount tested. However, the inter-laboratory variability was high (CV > 15%) compared to existing standards for bioanalytical assays. We identified and weighted the contributions to inter-laboratory variability of several parameters associated with the various pH-stat equipment used in this study (e.g. reaction vessel volume and shape, stirring mode and rate, burette volume for the automated delivery of sodium hydroxide). Based on this, we established recommendations for improving the reproducibility of lipase assays using the pH-stat technique. Defining accurate and complete recommendations on how to correctly quantify activity levels of enzyme preparations is a gateway to promising comparison of in vitro data obtained from different laboratories following the same in vitro digestion protocol.
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| 33. |
- Laskar, Ruhina S, et al.
(författare)
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Sex specific associations in genome wide association analysis of renal cell carcinoma.
- 2019
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Ingår i: European Journal of Human Genetics. - : Springer Science and Business Media LLC. - 1018-4813 .- 1476-5438. ; 27:10, s. 1589-1598
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Tidskriftsartikel (refereegranskat)abstract
- Renal cell carcinoma (RCC) has an undisputed genetic component and a stable 2:1 male to female sex ratio in its incidence across populations, suggesting possible sexual dimorphism in its genetic susceptibility. We conducted the first sex-specific genome-wide association analysis of RCC for men (3227 cases, 4916 controls) and women (1992 cases, 3095 controls) of European ancestry from two RCC genome-wide scans and replicated the top findings using an additional series of men (2261 cases, 5852 controls) and women (1399 cases, 1575 controls) from two independent cohorts of European origin. Our study confirmed sex-specific associations for two known RCC risk loci at 14q24.2 (DPF3) and 2p21(EPAS1). We also identified two additional suggestive male-specific loci at 6q24.3 (SAMD5, male odds ratio (ORmale) = 0.83 [95% CI = 0.78-0.89], Pmale = 1.71 × 10-8 compared with female odds ratio (ORfemale) = 0.98 [95% CI = 0.90-1.07], Pfemale = 0.68) and 12q23.3 (intergenic, ORmale = 0.75 [95% CI = 0.68-0.83], Pmale = 1.59 × 10-8 compared with ORfemale = 0.93 [95% CI = 0.82-1.06], Pfemale = 0.21) that attained genome-wide significance in the joint meta-analysis. Herein, we provide evidence of sex-specific associations in RCC genetic susceptibility and advocate the necessity of larger genetic and genomic studies to unravel the endogenous causes of sex bias in sexually dimorphic traits and diseases like RCC.
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| 34. |
- Ledoux, X, et al.
(författare)
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Spallation neutron production by 0.8, 1.2, and 1.6 GeV protons on Pb targets
- 1999
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Ingår i: PHYSICAL REVIEW LETTERS. - : AMERICAN PHYSICAL SOC. - 0031-9007. ; 82:22, s. 4412-4415
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Spallation neutron production in proton induced reactions on Pb targets at 0.8, 1.2, and 1.6 GeV has been measured at the SATURNE accelerator. Double-differential cross sections were obtained over a broad angular range from which averaged neutron multipli
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| 35. |
- Scelo, Ghislaine, et al.
(författare)
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Genome-wide association study identifies multiple risk loci for renal cell carcinoma.
- 2017
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Previous genome-wide association studies (GWAS) have identified six risk loci for renal cell carcinoma (RCC). We conducted a meta-analysis of two new scans of 5,198 cases and 7,331 controls together with four existing scans, totalling 10,784 cases and 20,406 controls of European ancestry. Twenty-four loci were tested in an additional 3,182 cases and 6,301 controls. We confirm the six known RCC risk loci and identify seven new loci at 1p32.3 (rs4381241, P=3.1 × 10-10), 3p22.1 (rs67311347, P=2.5 × 10-8), 3q26.2 (rs10936602, P=8.8 × 10-9), 8p21.3 (rs2241261, P=5.8 × 10-9), 10q24.33-q25.1 (rs11813268, P=3.9 × 10-8), 11q22.3 (rs74911261, P=2.1 × 10-10) and 14q24.2 (rs4903064, P=2.2 × 10-24). Expression quantitative trait analyses suggest plausible candidate genes at these regions that may contribute to RCC susceptibility.
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| 36. |
- Ainsworth, Elizabeth A., et al.
(författare)
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Next generation of elevated [CO2] experiments with crops: a critical investment for feeding the future world
- 2008
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Ingår i: Plant, Cell and Environment. - : Wiley. - 0140-7791 .- 1365-3040. ; 31:9, s. 1317-1324
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Tidskriftsartikel (refereegranskat)abstract
- A rising global population and demand for protein-rich diets are increasing pressure to maximize agricultural productivity. Rising atmospheric [CO2] is altering global temperature and precipitation patterns, which challenges agricultural productivity. While rising [CO2] provides a unique opportunity to increase the productivity of C-3 crops, average yield stimulation observed to date is well below potential gains. Thus, there is room for improving productivity. However, only a fraction of available germplasm of crops has been tested for CO2 responsiveness. Yield is a complex phenotypic trait determined by the interactions of a genotype with the environment. Selection of promising genotypes and characterization of response mechanisms will only be effective if crop improvement and systems biology approaches are closely linked to production environments, that is, on the farm within major growing regions. Free air CO2 enrichment (FACE) experiments can provide the platform upon which to conduct genetic screening and elucidate the inheritance and mechanisms that underlie genotypic differences in productivity under elevated [CO2]. We propose a new generation of large-scale, low-cost per unit area FACE experiments to identify the most CO2-responsive genotypes and provide starting lines for future breeding programmes. This is necessary if we are to realize the potential for yield gains in the future.
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| 37. |
- Castoldi, F, et al.
(författare)
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Autophagy-mediated metabolic effects of aspirin
- 2020
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Ingår i: Cell death discovery. - : Springer Science and Business Media LLC. - 2058-7716. ; 6:1, s. 129-
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Tidskriftsartikel (refereegranskat)abstract
- Salicylate, the active derivative of aspirin (acetylsalicylate), recapitulates the mode of action of caloric restriction inasmuch as it stimulates autophagy through the inhibition of the acetyltransferase activity of EP300. Here, we directly compared the metabolic effects of aspirin medication with those elicited by 48 h fasting in mice, revealing convergent alterations in the plasma and the heart metabolome. Aspirin caused a transient reduction of general protein acetylation in blood leukocytes, accompanied by the induction of autophagy. However, these effects on global protein acetylation could not be attributed to the mere inhibition of EP300, as determined by epistatic experiments and exploration of the acetyl-proteome from salicylate-treated EP300-deficient cells. Aspirin reduced high-fat diet-induced obesity, diabetes, and hepatosteatosis. These aspirin effects were observed in autophagy-competent mice but not in two different models of genetic (Atg4b−/− or Bcln1+/−) autophagy-deficiency. Aspirin also improved tumor control by immunogenic chemotherapeutics, and this effect was lost in T cell-deficient mice, as well as upon knockdown of an essential autophagy gene (Atg5) in cancer cells. Hence, the health-improving effects of aspirin depend on autophagy.
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| 38. |
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| 39. |
- Dujon, B, et al.
(författare)
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The nucleotide sequence of Saccharomyces cerevisiae chromosome XV
- 1997
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 387:6632, s. 98-102
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Tidskriftsartikel (refereegranskat)abstract
- Chromosome XV was one of the last two chromosomes of Saccharomyces cerevisiae to be discovered(1). It is the third-largest yeast chromosome after chromosomes XII and IV, and is very similar in size to chromosome VII. It alone represents 9% of the yeast genome (8% if ribosomal DNA is included). When systematic sequencing of chromosome XV was started, 93 genes or markers were identified, and most of them were mapped(2). However, very little else was known about chromosome XV which, in contrast to shorter chromosomes, had not been the object of comprehensive genetic or molecular analysis. It was therefore decided to start sequencing chromosome XV only in the third phase of the European Yeast Genome Sequencing Programme, after experience was gained on chromosomes III, XI and II (refs 3-5). The sequence of chromosome XV has been determined from a set of partly overlapping cosmid clones derived from a unique yeast strain, and physically mapped at 3.3-kilobase resolution before sequencing. As well as numerous new open reading frames (ORFs) and genes encoding tRNA or small RNA molecules, the sequence of 1,091,283 base pairs confirms the high proportion of orphan genes and reveals a number of ancestral and successive duplications with other yeast chromosomes.
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| 40. |
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| 41. |
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| 42. |
- Goubet, AG, et al.
(författare)
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Prolonged SARS-CoV-2 RNA virus shedding and lymphopenia are hallmarks of COVID-19 in cancer patients with poor prognosis
- 2021
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Ingår i: Cell death and differentiation. - : Springer Science and Business Media LLC. - 1476-5403 .- 1350-9047. ; 28:12, s. 3297-3315
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Tidskriftsartikel (refereegranskat)abstract
- Patients with cancer are at higher risk of severe coronavirus infectious disease 2019 (COVID-19), but the mechanisms underlying virus–host interactions during cancer therapies remain elusive. When comparing nasopharyngeal swabs from cancer and noncancer patients for RT-qPCR cycle thresholds measuring acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in 1063 patients (58% with cancer), we found that malignant disease favors the magnitude and duration of viral RNA shedding concomitant with prolonged serum elevations of type 1 IFN that anticorrelated with anti-RBD IgG antibodies. Cancer patients with a prolonged SARS-CoV-2 RNA detection exhibited the typical immunopathology of severe COVID-19 at the early phase of infection including circulation of immature neutrophils, depletion of nonconventional monocytes, and a general lymphopenia that, however, was accompanied by a rise in plasmablasts, activated follicular T-helper cells, and non-naive Granzyme B+FasL+, EomeshighTCF-1high, PD-1+CD8+ Tc1 cells. Virus-induced lymphopenia worsened cancer-associated lymphocyte loss, and low lymphocyte counts correlated with chronic SARS-CoV-2 RNA shedding, COVID-19 severity, and a higher risk of cancer-related death in the first and second surge of the pandemic. Lymphocyte loss correlated with significant changes in metabolites from the polyamine and biliary salt pathways as well as increased blood DNA from Enterobacteriaceae and Micrococcaceae gut family members in long-term viral carriers. We surmise that cancer therapies may exacerbate the paradoxical association between lymphopenia and COVID-19-related immunopathology, and that the prevention of COVID-19-induced lymphocyte loss may reduce cancer-associated death.
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| 43. |
- Hogan, C. J., et al.
(författare)
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Fission yeast Iec1-Ino80-mediated nucleosome eviction regulates nucleotide and phosphate metabolism
- 2010
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Ingår i: Molecular and Cellular Biology. - 0270-7306 .- 1098-5549. ; 30:3, s. 657-674
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Tidskriftsartikel (refereegranskat)abstract
- Ino80 is an ATP-dependent nucleosome-remodeling enzyme involved in transcription, replication, and the DNA damage response. Here, we characterize the fission yeast Ino80 and find that it is essential for cell viability. We show that the Ino80 complex from fission yeast mediates ATP-dependent nucleosome remodeling in vitro. The purification of the Ino80-associated complex identified a highly conserved complex and the presence of a novel zinc finger protein with similarities to the mammalian transcriptional regulator Yin Yang 1 (YY1) and other members of the GLI-Krüppel family of proteins. Deletion of this Iec1 protein or the Ino80 complex subunit arp8, ies6, or ies2 causes defects in DNA damage repair, the response to replication stress, and nucleotide metabolism. We show that Iec1 is important for the correct expression of genes involved in nucleotide metabolism, including the ribonucleotide reductase subunit cdc22 and phosphate- and adenineresponsive genes. We find that Ino80 is recruited to a large number of promoter regions on phosphate starvation, including those of phosphate- and adenine-responsive genes that depend on Iec1 for correct expression. Iec1 is required for the binding of Ino80 to target genes and subsequent histone loss at the promoter and throughout the body of these genes on phosphate starvation. This suggests that the Iec1-Ino80 complex promotes transcription through nucleosome eviction.
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| 44. |
- Makhani, Naila, et al.
(författare)
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The diagnostic workup of children with the radiologically isolated syndrome differs by age and by sex
- 2024
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Ingår i: Journal of Neurology. - : Springer. - 0340-5354 .- 1432-1459.
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Tidskriftsartikel (refereegranskat)abstract
- Background: Cerebrospinal fluid (CSF) and spinal MRIs are often obtained in children with the radiologically isolated syndrome (RIS) for diagnosis and prognosis. Factors affecting the frequency and timing of these tests are unknown.Objective: To determine whether age or sex were associated with (1) having CSF or spinal MRI obtained or (2) the timing of these tests.Methods: We analyzed children (≤ 18 y) with RIS enrolled in an international longitudinal study. Index scans met 2010/2017 multiple sclerosis (MS) MRI criteria for dissemination in space (DIS). We used Fisher's exact test and multivariable logistic regression (covariates = age, sex, MRI date, MRI indication, 2005 MRI DIS criteria met, and race).Results: We included 103 children with RIS (67% girls, median age = 14.9 y). Children ≥ 12 y were more likely than children < 12 y to have CSF obtained (58% vs. 21%, adjusted odds ratio [AOR] = 4.9, p = 0.03). Pre-2017, girls were more likely than boys to have CSF obtained (n = 70, 79% vs. 52%, AOR = 4.6, p = 0.01), but not more recently (n = 30, 75% vs. 80%, AOR = 0.2, p = 0.1; p = 0.004 for interaction). Spinal MRIs were obtained sooner in children ≥ 12 y (median 11d vs. 159d, p = 0.03).Conclusions: Younger children with RIS may be at continued risk for misdiagnosis and misclassification of MS risk. Consensus guidelines are needed.
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| 45. |
- Malbet, F., et al.
(författare)
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High precision astrometry mission for the detection and characterization of nearby habitable planetary systems with the Nearby Earth Astrometric Telescope (NEAT)
- 2012
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Ingår i: Experimental Astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 34:2, s. 385-413
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Tidskriftsartikel (refereegranskat)abstract
- A complete census of planetary systems around a volume-limited sample of solar-type stars (FGK dwarfs) in the Solar neighborhood (d a parts per thousand currency signaEuro parts per thousand 15 pc) with uniform sensitivity down to Earth-mass planets within their Habitable Zones out to several AUs would be a major milestone in extrasolar planets astrophysics. This fundamental goal can be achieved with a mission concept such as NEAT-the Nearby Earth Astrometric Telescope. NEAT is designed to carry out space-borne extremely-high-precision astrometric measurements at the 0.05 mu as (1 sigma) accuracy level, sufficient to detect dynamical effects due to orbiting planets of mass even lower than Earth's around the nearest stars. Such a survey mission would provide the actual planetary masses and the full orbital geometry for all the components of the detected planetary systems down to the Earth-mass limit. The NEAT performance limits can be achieved by carrying out differential astrometry between the targets and a set of suitable reference stars in the field. The NEAT instrument design consists of an off-axis parabola single-mirror telescope (D = 1 m), a detector with a large field of view located 40 m away from the telescope and made of 8 small movable CCDs located around a fixed central CCD, and an interferometric calibration system monitoring dynamical Young's fringes originating from metrology fibers located at the primary mirror. The mission profile is driven by the fact that the two main modules of the payload, the telescope and the focal plane, must be located 40 m away leading to the choice of a formation flying option as the reference mission, and of a deployable boom option as an alternative choice. The proposed mission architecture relies on the use of two satellites, of about 700 kg each, operating at L2 for 5 years, flying in formation and offering a capability of more than 20,000 reconfigurations. The two satellites will be launched in a stacked configuration using a Soyuz ST launch vehicle. The NEAT primary science program will encompass an astrometric survey of our 200 closest F-, G- and K-type stellar neighbors, with an average of 50 visits each distributed over the nominal mission duration. The main survey operation will use approximately 70% of the mission lifetime. The remaining 30% of NEAT observing time might be allocated, for example, to improve the characterization of the architecture of selected planetary systems around nearby targets of specific interest (low-mass stars, young stars, etc.) discovered by Gaia, ground-based high-precision radial-velocity surveys, and other programs. With its exquisite, surgical astrometric precision, NEAT holds the promise to provide the first thorough census for Earth-mass planets around stars in the immediate vicinity of our Sun.
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| 46. |
- Ougazzaden, A., et al.
(författare)
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Growth of GaN by metal organic vapor phase epitaxy on ZnO-buffered c-sapphire substrates
- 2008
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Ingår i: Journal of Crystal Growth. - : Elsevier BV. - 0022-0248 .- 1873-5002. ; 310:5, s. 944-947
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Tidskriftsartikel (refereegranskat)abstract
- The materials quality and availability of large-area bulk GaN substrates is currently considered a key problem for the continuing development of improved GaN-based devices. Since industrial fabrication of bulk GaN substrates with suitable materials quality has proven very difficult, the opto-GaN industry is currently based on heteroepitaxy using either c-sapphire or 6H SiC substrates. ZnO is promising as a substrate material for GaN because it has the same wurtzite structure and a relatively small lattice mismatch (similar to 1.8%). In this study, we have successfully grown GaN by MOVPE on ZnO-buffered c-sapphire. The growth conditions required to both prevent ZnO degradation and grow monocrystal thin film of GaN have been obtained. SEM, HRXRD and micro-Raman characterizations underlined the presence of the two layers GaN and ZnO with high structural quality.
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| 47. |
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| 48. |
- Tison, J.-L., et al.
(författare)
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Retrieving the paleoclimatic signal from the deeper part of the EPICA Dome C ice core
- 2015
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Ingår i: The Cryosphere. - : Copernicus GmbH. - 1994-0416 .- 1994-0424. ; 9:4, s. 1633-1648
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Tidskriftsartikel (refereegranskat)abstract
- An important share of paleoclimatic information is buried within the lowermost layers of deep ice cores. Because improving our records further back in time is one of the main challenges in the near future, it is essential to judge how deep these records remain unaltered, since the proximity of the bedrock is likely to interfere both with the recorded temporal sequence and the ice properties. In this paper, we present a multiparametric study (delta D-delta O-18(ice), delta O-18(atm), total air content, CO2, CH4, N2O, dust, high-resolution chemistry, ice texture) of the bottom 60 m of the EPICA (European Project for Ice Coring in Antarctica) Dome C ice core from central Antarctica. These bottom layers were subdivided into two distinct facies: the lower 12 m showing visible solid inclusions (basal dispersed ice facies) and the upper 48 m, which we will refer to as the basal clean ice facies. Some of the data are consistent with a pristine paleoclimatic signal, others show clear anomalies It is demonstrated that neither large-scale bottom refreezing of subglacial water, nor mixing (be it internal or with a local basal end term from a previous/initial ice sheet configuration) can explain the observed bottom-ice properties. We focus on the high-resolution chemical profiles and on the available remote sensing data on the subglacial topography of the site to propose a mechanism by which relative stretching of the bottom-ice sheet layers is made possible, due to the progressively confining effect of subglacial valley sides. This stress field change, combined with bottom-ice temperature close to the pressure melting point, induces accelerated migration recrystallization, which results in spatial chemical sorting of the impurities, depending on their state (dissolved vs. solid) and if they are involved or not in salt formation. This chemical sorting effect is responsible for the progressive build-up of the visible solid aggregates that therefore mainly originate from within, and not from incorporation processes of debris from the ice sheet's substrate. We further discuss how the proposed mechanism is compatible with the other ice properties described. We conclude that the paleoclimatic signal is only marginally affected in terms of global ice properties at the bottom of EPICA Dome C, but that the timescale was considerably distorted by mechanical stretching of MIS20 due to the increasing influence of the subglacial topography, a process that might have started well above the bottom ice. A clear paleoclimatic signal can therefore not be inferred from the deeper part of the EPICA Dome C ice core. Our work suggests that the existence of a flat monotonic ice bedrock interface, extending for several times the ice thickness, would be a crucial factor in choosing a future oldest ice drilling location in Antarctica.
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| 49. |
- Tremblin, P., et al.
(författare)
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Site testing for submillimetre astronomy at Dome C, Antarctica
- 2011
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 535:A112
-
Tidskriftsartikel (refereegranskat)abstract
- Aims. Over the past few years a major effort has been put into the exploration of potential sites for the deployment of submillimetre astronomical facilities. Amongst the most important sites are Dome C and Dome A on the Antarctic Plateau, and the Chajnantor area in Chile. In this context, we report on measurements of the sky opacity at 200 mu m over a period of three years at the French-Italian station, Concordia, at Dome C, Antarctica. We also present some solutions to the challenges of operating in the harsh polar environment.Methods. The 200-mu m atmospheric opacity was measured with a tipper. The forward atmospheric model MOLIERE (Microwave Observation LIne Estimation and REtrieval) was used to calculate the atmospheric transmission and to evaluate the precipitable water vapour content (PWV) from the observed sky opacity. These results have been compared with satellite measurements from the Infrared Atmospheric Sounding Interferometer (IASI) on Metop-A, with balloon humidity sondes and with results obtained by a ground-based microwave radiometer (HAMSTRAD). In addition, a series of experiments has been designed to study frost formation on surfaces, and the temporal and spatial evolution of thermal gradients in the low atmosphere.Results. Dome C offers exceptional conditions in terms of absolute atmospheric transmission and stability for submillimetre astronomy. Over the austral winter the PWV exhibits long periods during which it is stable and at a very low level (0.1 to 0.3 mm). Higher values (0.2 to 0.8 mm) of PWV are observed during the short summer period. Based on observations over three years, a transmission of around 50% at 350 mu m is achieved for 75% of the time. The 200-mu m window opens with a typical transmission of 10% to 15% for 25% of the time.Conclusions. Dome C is one of the best accessible sites on Earth for submillimetre astronomy. Observations at 350 or 450 mu m are possible all year round, and the 200-mu m window opens long enough and with a sufficient transparency to be useful. Although the polar environment severely constrains hardware design, a permanent observatory with appropriate technical capabilities is feasible. Because of the very good astronomical conditions, high angular resolution and time series (multi-year) observations at Dome C with a medium size single dish telescope would enable unique studies to be conducted, some of which are not otherwise feasible even from space.
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| 50. |
- Borne, F, et al.
(författare)
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Spallation neutron spectra measurements .1. Time-of-flight technique
- 1997
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Ingår i: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT. - : ELSEVIER SCIENCE BV. - 0168-9002. ; 385:2, s. 339-344
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- We present an experimental method based on a time-of-flight technique between the tagged incident particles and a thick liquid NE213 scintillator to measure neutron energy spectra from 3 to 400 MeV at the Saturne synchrotron of Saclay. Efficiency measurem
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