Kooperativer Bibliotheksverbund

Berlin Brandenburg


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  • 1
    Language: French
    In: Quaternaire, 01 September 2011, pp.261-271
    Description: L’étalonnage de l’échelle des temps du radiocarbone repose sur la datation de chronologies absolues de cernes (chronologies de référence). L’incision récente des dépôts alluviaux tardiglaciaires du torrent des Barbiers (région de la Moyenne Durance, Alpes du Sud) a fourni un gisement de pins sylvestres subfossiles, datés au radiocarbone de la transition entre l’Alleröd et le Dryas Récent. Leur analyse dendrochronologique a permis de construire deux chronologies flottantes (BARBA et BARBB). Par la méthode du wiggle matching, ces chronologies permettent de couvrir le hiatus temporel existant entre le début de la chronologie de référence européenne (12 594 cal. BP, Schaub, 2008a ; Hua et al., 2009) et la fin de la longue chronologie flottante suisse (Kaiser et al., 2010), fournissant ainsi un calendrier continu du temps du radiocarbone pour les derniers 14 300 ans. Malheureusement les chronologies suisses et françaises ne sont pas encore interdatées.
    Keywords: Bois Subfossile ; Chronologie Absolue ; Chronologies Flottantes ; Pinus Sylvestris ; Radiocarbone ; Tardiglaciaire ; Wiggle Matching ; Absolute Chronologies ; Floating Chronology ; Lateglacial ; Radiocarbon ; Scots Pines ; Subfossil Wood ; Wiggle Matching ; Geology
    ISSN: 1142-2904
    E-ISSN: 1965-0795
    Source: OpenEdition Journals
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  • 2
  • 3
    Language: English
    In: Humic Substances in Terrestrial Ecosystems, Chapter 3, pp.101-170
    Description: This chapter studies the organic matter dynamics in the forest soils of temperate and tropical ecosystems by detailed morphological observations, including micromorphology, and a combination of spectroscopic and chemical degradation methods. It discusses the primary resources like plant debris that are related to the parent materials of humification. Research is conducted to elucidate the role of secondary resources like microbial and animal residues, and of black carbon as a possible source of humic materials. The pathways of humification differ according to the chemical composition of the resources. Microbial resynthesis is important for proteins and carbohydrates, but protection of polysaccharides by recalcitrant molecules may occur. Mineralization of carbohydrates is responsible for the decline of O-alkyl C from the soil surface down to the deepest forest soil A subhorizon. Within the forest soil profiles, lignin is altered by side-chain oxidation, demethoxylation, and loss of phenolic structures. The evident increase of aryl C in humus-rich mineral soils is the result of a relative accumulation of the stable nonlignin structures. The chapter also discusses the dynamics of alkyl-C compounds.
    ISBN: 978-0-444-81516-3
    Source: ScienceDirect (Elsevier B.V.)
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  • 4
    Language: French
    In: Revue medicale suisse, 19 September 2018, Vol.14(619), pp.1660-1664
    Description: Negative symptoms in schizophrenia can be categorized in the symptom-dimensions of apathy (avolition, anhedonia and social withdrawal) and reduced expression (blunted affect and alogia). Based on the strong relevance for the quality of life and functional outcome during the course of an illness, a differentiated diagnostic and therapeutic approach is of high importance. Such a differentiation specifies primary negative symptoms (regarded as an integral part of schizophrenia) and secondary negative symptoms (regarded as a result of positive symptoms, comorbid depression, effects of antipsychotic medication, substance abuse or social deprivation). The following overview will summarize the various aspects of negative symptoms and discuss current diagnostic and therapeutic recommendations.
    ISSN: 1660-9379
    Source: MEDLINE/PubMed (U.S. National Library of Medicine)
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  • 5
    Language: English
    In: Annales Des Télécommunications, 2003, Vol.58(9), pp.1424-1431
    Description: We present first results of the investigations of the quantum noise properties of resonant-cavity light-emitting diodes ( rcled s). We obtain a quantum noise of up to −0.07dB below the shot noise quantum limit already at moderate pump levels and when being pumped by a quiet current source. This amount of observed sub-shot noise emission is in accordance with the quantum efficiency of the devices. This Sub-Poisson intensity noise of rcled s together with their narrow beam characteristics make them very attractive for applications in photonics and metrology. Nous présentons les premiers résultats des études du bruit quantique des diodes électroluminescentes à cavité résonante. Nous obtenons un bruit jusqu’à — 0,07 dB au-dessous de la limite quantique du bruit de grenaille même à des niveaux de pompe modérés et avec pompage par une source calme. La valeur observée de ce bruit sous-poissonnien est en accord avec le rendement quantique des diodes électroluminescentes. Finalement, ces résultats démontrent que les diodes électroluminescentes à cavité résonante seront très intéressantes pour des applications en métrologie spectroscopique et en photonique.
    Keywords: Light-emitting diode ; Cavity resonator ; Quantum noise ; Quantum effect
    ISSN: 0003-4347
    E-ISSN: 1958-9395
    Source: Springer Science & Business Media B.V.
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