Search results for "UNIVERSE"
showing 10 items of 2171 documents
Gaia -ESO Survey: Analysis of pre-main sequence stellar spectra
2015
This paper describes the analysis of UVES and GIRAFFE spectra acquired by the Gaia-ESO Public Spectroscopic Survey in the fields of young clusters whose population includes pre-main sequence (PMS) stars. Both methods that have been extensively used in the past and new ones developed in the contest of the Gaia-ESO survey enterprise are available and used. The internal precision of these quantities is estimated by inter-comparing the results obtained by such different methods, while the accuracy is estimated by comparison with independent external data, like effective temperature and surface gravity derived from angular diameter measurements, on a sample of benchmarks stars. Specific strategi…
Geochemistry of REE, Zr and HF in a wide range of pH and water composition: The Nevado del Ruiz volcano hydrothermal system (Colombia)
2015
International audience; The geochemical behaviour of Rare Earth Elements, Zr and Hf was investigated in the thermal waters of Nevado del Ruiz volcano system. A wide range of pH, between 1.0 and 8.8, characterizes these fluids. The acidic waters are sulphate dominated with different Cl/SO4 ratios. The important role of the pH and the ionic complexes for the distribution of REE, Zr and Hf in the aqueous phase was evidenced. The pH rules the precipitation of authigenic Fe and Al oxyhydroxides producing changes in REE, Zr, Hf amounts and strong anomalies of Cerium. The precipitation of alunite and jarosite removes LREE from the solution, changing the REE distribution in acidic waters.Y–Ho and Z…
Measurement of acoustic attenuation in South Pole ice
2010
Using the South Pole Acoustic Test Setup (SPATS) and a retrievable transmitter deployed in holes drilled for the IceCube experiment, we have measured the attenuation of acoustic signals by South Pole ice at depths between 190 m and 500 m. Three data sets, using different acoustic sources, have been analyzed and give consistent results. The method with the smallest systematic uncertainties yields an amplitude attenuation coefficient alpha = 3.20 \pm 0.57 km^(-1) between 10 and 30 kHz, considerably larger than previous theoretical estimates. Expressed as an attenuation length, the analyses give a consistent result for lambda = 1/alpha of ~1/300 m with 20% uncertainty. No significant depth or …
Correlation of the highest-energy cosmic rays with nearby extragalactic objects.
2007
Using data collected at the Pierre Auger Observatory during the past 3.7 years, we demonstrated a correlation between the arrival directions of cosmic rays with energy above ~ 6x10^{19} electron volts and the positions of active galactic nuclei (AGN) lying within ~ 75 megaparsecs. We rejected the hypothesis of an isotropic distribution of these cosmic rays with at least a 99% confidence level from a prescribed a priori test. The correlation we observed is compatible with the hypothesis that the highest energy particles originate from nearby extragalactic sources whose flux has not been substantially reduced by interaction with the cosmic background radiation. AGN or objects having a similar…
The “chimney forest” of the deep Montenegrin margin, south-eastern Adriatic Sea
2015
A spectacular field of columnar carbonates has been discovered on the Montenegrin margin in the southern Adriatic Sea at a depth of about 450 m. The site exposes many columnar carbonates protruding from the substrate or abated on the bottom. Such carbonates attain maximum visible lengths of ca. 60 cm with diameters up to 20 cm; display an annular growth, and are either hollow or plugged by indurated sediment. Petrographic and geochemical analyses document the pervasive presence of dolomite, and delta C-13 values as low as -30%(0) VPDB. These 'chimneys' are therefore interpreted as former conduits related to hydrocarbon expulsion in this sector of the Adriatic basin. However, available data …
Tap water consumers differ from non-consumers in chlorine flavor acceptability but not sensitivity
2010
International audience; Unpleasant taste and especially chlorine flavor is one of the most common reasons advocated for choosing tap water alternatives as drinking water. As a consequence, the putative link between sensitivity to chlorine flavor and tap water consumption is an issue in drinking water habits studies. In the present study, we set out to examine such a link following a strategy in which we measured chlorine flavor perception at threshold and supra-threshold level for two groups of participants selected on their drinking water consumption habits. The first group included exclusive tap water consumers and the second group included exclusive bottled water consumers. In a first ex…
Montagnes d’Afrique tropicale : marqueurs de la variabilité climatique ou isolats climatiques ?
2011
6 pages; International audience; Les montagnes tropicales sont souvent perçues comme des sentinelles des changements climatiques. Pour autantles variations climatiques interannuelles à décennales sont-elles le reflet de celles des espaces environnants ? A l’échelle del’Afrique au sud du Sahara, une analyse de la variabilité des pluies entre 1941 et 2000 montre une cohérence spatiale peudiminuée par les reliefs. Des exemples sont présentés de reliefs constituant même des révélateurs de la dynamiqueatmosphérique et de la variabilité climatique d’échelles larges.
Etude diagnostique de nouvelles données climatiques : les réanalyses. Exemples d'application aux précipitations en Afrique tropicale
2000
This study establishes an objective diagnosis of NCEP/NCAR reanalysis data reliability over tropical Africa at intra-seasonal to interannuel space scale. The reanalysis data are an original database available over 1958-1998 period which combines observations and atmospheric model outputs and allows us to better understand global scale atmospheric dynamics. The study of data reliability allows us to identify a great number of recommendations for using them. Over tropical Africa, the homogeneous period which should be extracted goes from 1968 to 1998. Before this year, reanalysed datasets should be used with greatest caution. However, during this period, the SMWDA, a statistical method used t…
Etude des interactions dans la formation d'agrégats thermiques mixtes entre globulines de pois et béta-lactoglobuline : application à l'élaboration d…
2016
In the context of protein source diversification, pea protein is a promising ingredient and may be associated with milk proteins such as whey proteins in the production of new food products. In the present work, the thermal aggregation (85°C - 1 h) of pea globulins (Glob) alone and in admixture with β-lactoglobulin (βlg), prior to acid gelation, was studied as a function of total protein concentration, βlg/Glob weight ratio and ionic strength. The characterization of soluble aggregates was carried out by combining different analytical methods such as surface hydrophobicity determination, disulfide bridge quantification, dynamic light scattering (DLS), size exclusion chromatography (SEC-HPLC…
On Inductive Generalization in Monadic First-Order Logic With Identity
1966
Publisher Summary The chapter examines the results obtained by means of a system when the relation of identity is used in addition to monadic predicates. The chapter compares the new system of inductive logic sketched by Jaakko Hintikka with Carnap's system. The main advantage of Hintikka's system is that it gives natural degrees of confirmation to inductive generalizations, whereas Carnap's confirmation function c * enables one to deal satisfactorily with singular inductive inference only. According to Carnap's system, general sentences that are not logically true receive nonnegligible degrees of confirmation only if the evidence contains a large part of the individuals in the whole univer…