506 research outputs found
Préface
No full textProbst J.L. Préface. In: Sciences Géologiques. Bulletin, tome 49, n°1-4, 1996. Fleuves et érosion, sous la direction de Jean-Luc Probst . pp. 3-5
Préface
No full textProbst J.L. Préface. In: Sciences Géologiques. Bulletin, tome 49, n°1-4, 1996. Fleuves et érosion, sous la direction de Jean-Luc Probst . pp. 3-5
Préface
No full textDedieu Gérard, Probst J.L. Préface. In: Sciences Géologiques. Bulletin, tome 50, n°1-4, 1997. The global carbon cycle in the terrestrial biosphere, sous la direction de Gérard Dedieu et Jean-Luc Probst. pp. 3-5
Préface
No full textDedieu Gérard, Probst J.L. Préface. In: Sciences Géologiques. Bulletin, tome 50, n°1-4, 1997. The global carbon cycle in the terrestrial biosphere, sous la direction de Gérard Dedieu et Jean-Luc Probst. pp. 3-5
George E. Probst Papers
No full textGeorge E. Probst (1917-1986) held many positions in both broadcasting and education from 1944 to 1983: Executive Director, Office of Radio and Television, University of Chicago (1944-1954); Founder, director and Producer, University of Chicago Roundtable (NBC) (1944-1954); Chairman, committee that presented before the Federal Communications Commission (FCC) the case for assigning television channels for education (1949-1950): Chairman, finance committee, Joint Committee on Educational Television (JCET) (1950-1952); Chairman, Committee of all educational institutions, Chicago Metropolitan Area Educational Television (1951-1953; Chairman, Adult Education Committee administering Fund for Adult Education grant for production of radio series The Jefferson Heritage (co-author), Ways of Mankind, People Under Communism, Voice of Europe(1951-1953); Director, radio and television programming, WGBH (Boston, MA) (1954); Co-founder, President, Broadcast Foundation of America (1955-1983); Producer, director, writer,Democracy in America, a series based on Alexis de Tocqueville's observations of American life and politics (1958); Director, National Educational Television and Radio Center (1960-1966); Executive Director, National Commission for Cooperative Education (1966-1976); Consultant, U.S. Office of Education (1968-1976). The collection documents Probst's participation in National Conference on Citizens Rights in Broadcasting, October 1970 as well as the public television programms: Tocqueville's America and The University of Chicago Roundtable
Heavy metals partioning in three French forest soils by sequential extraction procedure
No full textTo know the concentration of heavy metal associated to chemical compounds is important to evaluate the environmental risks on soils, particularly regarding ion bioavailability. The relative mobility and strength of binding of heavy metals to the soil components can be studied using a sequential extraction procedure which provides a meaningful comparison between different soil profiles. The heavy metals partitioning bas been identified in three different french forest soils : one cambic podzol, one calcaric cambisol and one mollic andosol, using a new sequential extraction method. Results show that metal fractionation is metal and site specific. The water leaching phase does not contain any metals. The proportion of heavy metal leached in the exchangeable and the acid — soplhuabslee is significant for Cd. The residual
phase is important for Cr, Pb, and to a lesser extend for Ni. The organic matter fraction is dominant for Zn and Cu. Thus, the considered heavy metals are mainly bounded to iron oxides, to the organic matter and to the mineral residue. The order of heavy metals availability in the three soils would be : Zn>Cd>Cu>Pb>NiL&egatd;C r.i sotopes in some extracts of the extraction procedure corroborate the anthropogenic inputs for two soils. These both infomations allow to trace the origin, the mobility and the distribution of Pb in the soil
The contribution of weathering of the main Alpine rivers on the global carbon cycle
No full textOn geological time-scales the carbon fluxes from the solid Earth to the atmosphere mainly result from volcanism and metamorphic-decarbonation processes, whereas the carbon fluxes from atmosphere to solid Earth mainly depend on weathering of silicates and carbonates, biogenic precipitation and removal of CaCO3 in the oceans and volcanic gases – seawater interactions. Quantifying each contribution is critical. In this work, we estimate the atmospheric CO2 uptake by weathering in the Alps, using results of the study of the dissolved loads transported by 33 main Alpine rivers. The chemical composition of river water in unpolluted areas is a good indicator of surface weathering processes (Garrels and Mackenzie, 1971; Drever, 1982; Meybeck, 1984; Tardy, 1986; Berner and Berner, 1987; Probst et al., 1994). The dissolved load of streams originates from atmospheric input, pollution, evaporite dissolution, and weathering of carbonate and silicate rocks, and the application of mass balance calculations allows quantification of the different contributions. In this work, we applied the MEGA (Major Element Geochemical Approach) geochemical code (Amiotte Suchet, 1995; Amiotte Suchet and Probst, 1996) to the chemical compositions of the selected rivers in order to quantify the atmospheric CO2 consumed by weathering in Alpine region. The drainage basins of the main Alpine rivers were sampled near the basin outlets during dry and flood seasons. The application of the MEGA geochemical consisted in several steps. First, we subtracted the rain contribution in river waters knowing the X/Cl (X = Na, K, Mg, Ca) ratios of the rain. Next, we considered that all (Na+K) came from silicate weathering. The average molar ratio Rsil = (Na+K)/(Ca+Mg) for rivers draining silicate terrains was estimated from unpolluted French stream waters draining small monolithological basins (Meybeck, 1986; 1987). For the purpose, we prepared a simplified geo-lithological map of Alps according to the lithological classification of Meybeck (1986, 1987). Then for each basin we computed Rsil weighted average considering the surface and the mean precipitation for the surface area of each lithology. Lastly, we estimated the (Ca+Mg) originating from carbonate weathering as the remaining cations after silicate correction. Depending on time-scales of the phenomena (shorter than about 1 million year i.e. correlated to the short term carbon cycle, or longer than about 1 million years i.e. correlated to the long-term carbon cycle), we considered different equations for the quantification of the atmospheric CO2 consumed by weathering (Huh, 2010). The results show the net predominance of carbonate weathering on fixing atmospheric CO2 and that, considering the long-term carbon cycle, the amount of atmospheric CO2 uptake by weathering is about one order of magnitude lower than considering the short-term carbon cycle. Moreover, considering the short-term carbon cycle, the mean CO2 consumed by Alpine basins is of the same order of magnitude of the mean CO2 consumed by weathering by the 60 largest rivers of the world estimated by Gaillardet et al. (1999)
Happytime Series #24
No full textThis booklet presents two irregularities or anomalies. First, it is missing four pages at its center. WL seems just to have ended, and we find ourselves suddenly on the last page of The Wolf Who Became a Shepherd. The second anomaly grows out of the fact that this edition acknowledges that it is a translation by arrangement with Librairie Hachette. The book in question seems to be La Fontaine: Fables from Hachette in 1953. Three of that book's four stories are presented here, including the exact same pictures. The anomaly is that that book proclaims Imagées par Romain Simon, while this has Pictures by Pierre Probst. The texts for what we have here follow La Fontaine's versions. As I say concerning that book, of the simple, lively colored illustrations, two stand out for me. Both illustrate MSA. The former, on the title-page, shows a disgruntled father with a happy child as both sit on the beast. The latter, on the last page, pictures the two flanking the beast and walking arm-in-arm with it. Now all three are happy!Traduit du Latin par E. Panckouck
Significance of floods in metal dynamics and export in a small agricultural catchment
No full textHigh-resolution monitoring of water discharge and water sampling were performed between early October 2006 and late September 2007 in the Montoussé River, a permanent stream draining an experimental agricultural catchment in Gascogne region (SW France). Dissolved and particulate concentrations of major elements and trace metals (i.e. Al, Fe, Mn, As, Cd, Cr, Cu, Ni, Pb, Sc and Zn) were examined. Our results showed that contamination levels were deficient to moderate, as a result of sustainable agricultural practices. Regarding dynamics, metal partitioning between particulate and dissolved phases was altered during flood conditions: the particulate phase was diluted by coarser and less contaminated particles from river bottom and banks, whereas the liquid phase was rapidly enriched owing to desorption mechanisms. Soluble/reactive elements were washed-off from soils at the beginning of the rain episode. The contribution of the flood event of May 2007 (by far the most significant episode over the study period) to the annual metal export was considerable for particulate forms (72–82%) and moderate for dissolved elements (0–20%). The hydrological functioning of the Montoussé stream poses dual threat on ecosystems, the consequences of which differ from both temporal and spatial scales: (i) desorption processes at the beginning of floods induce locally a rapid enrichment (up to 3.4-fold the pre-flood signatures on average for the event of May 2007) of waters in bioavailable metals, and (ii) labile metals – enriched by anthropogenic sources – associated to particles (mainly via carbonates and Fe/Mn oxides), were predominantly transferred during floods into downstream-connected rivers
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