The Hartree-Fock triplet instability: influence of conformation and substitution
; Dive, Georges ; Dehareng, Dominique
in Journal of Molecular Structure-theochem (2006), 760(1-3), 75-85
The triplet Hartree-Fock (HF) instability is investigated through the examples of substituted ethylenes and the small linear conjugated systems butadiene, hexatriene, octatetraene. A statistical analysis ... [more ▼]
The triplet Hartree-Fock (HF) instability is investigated through the examples of substituted ethylenes and the small linear conjugated systems butadiene, hexatriene, octatetraene. A statistical analysis is performed for several conformations of the latters. The second eigenvalue of the instability matrix appears to be able to discriminate the groups of unsaturated compounds. The HF instability is largely influenced by conjugation and mesomeric effects and thus by the geometry. The number of pi electrons is also an important factor. The electronic correlation related to the HF instability is not quantified by the energy difference between the post-HF and HF levels. (c) 2005 Elsevier B.V. All rights reserved. [less ▲]Detailed reference viewed: 44 (3 ULg)
Has disinfection of endoscopes by automatic machines become obligatory?
Delwaide, Jean ; ; et al
in Revue Médicale de Bruxelles (1999), 20(1), 49-50Detailed reference viewed: 4 (0 ULg)
Has oxygen depletion an impact on nutrients and macrofauna in a highly dynamic macrophytodetritus accumulation?
Remy, François ; Mascart, Thibaud ; Dauby, Patrick et al
Poster (2014, May 06)
Posidonia oceanica is an endemic Mediterranean highly productive seagrass. Depending on the ability of the primary consumers to digest it alive, a generally important part of its foliar primary production ... [more ▼]
Posidonia oceanica is an endemic Mediterranean highly productive seagrass. Depending on the ability of the primary consumers to digest it alive, a generally important part of its foliar primary production falls in autumn, to decay inside the meadow or to be exported to sand patches to form “exported litter accumulations”. These accumulations are highly dynamic depending on hydrodynamics and seafloor geomorphology. Literature says that low O2 conditions might occur inside litter accumulations, but the annual oxygen dynamics or its impact on the litter-associated macrofauna has never been measured. We focused on 2 exported litter accumulations in Calvi Bay (Corsica), during 2 years for a total of 8 seasons. For each season, we collected water samples (n=6) from 3 different strata: Water Column (WC), Water Just Above the litter (WJA) and Water Inside the litter (WI). Oxygen was measured for each replicate using a Winkler-based automated routine for oxygen concentration measurements on micro-volumes. At the same time, nutrients concentrations (PO4, NH4, and NO2+NO3) were measured in WC, WJA and WI, but also in the Interstitial Water (IW) using a spectrophotometric continuous flow analyzer (adapted for low nutrients level in an oligotrophic environment). In parallel, macrofaunal (size >500µm) samples (n=3-6) were also collected, counted and identified to the specific level. Our results show significant differences between O2 concentrations/saturation from WI and the two other strata. Significant differences were detected between seasons, sites and years for WI which is the only stratum where really low O2 conditions can be observed. Significant differences were also detected between seasons for both WC and WJA but no differences between sites and years. On the other hand no significant differences were detected between WC and WJA. A similar observation was made for the nutrients at the annual, seasonal and spatial level. Moreover differences are also observed between the nutrients themselves. Our data shows no correlation between WI O2 concentrations and saturation, and global macrofauna abundance or biodiversity. Results are more contrasting at an individual specific level for the 4 most dominant species. For two amphipod species, Gammarella fucicola (55% of the global abundance) and Gammarus aequicauda, no significant correlations were detected between their abundance and O2. For the leptostracan species, Nebalia strausi, a significant negative correlation with O2 concentration was detected. For the last amphipod species, Melita hergensis, a significant positive correlation was observed. Our analyses also show significant correlations between WI O2 concentration/saturation, and WI / IW nutrients concentration. To conclude, this work shows that WI is a very particular and dynamic environment considering O2 concentration and saturation. Low O2 conditions can be observed in WI but never in WC or WJA showing that internal processes and relations with the sediment determine the O2 dynamics in WI and showing a potential “barrier” effect between WI and WC. Moreover O2 dynamics and its consequences may play a role in the nutrients dynamics and cycles. It is clear that faunal responses to low O2 conditions are not identifiable at a global community level. At a specific level, we show a more complex situation: some species do not seem to be impacted by low O2 conditions, but some present a significant positive, or a significant negative response. This shows the existence and complexity of species-dependent low O2 tolerance/adaptation, and the importance of a specific level data analyses to detect responses of dominant litter associated macro- invertebrates to O2 concentration and saturation variations. [less ▲]Detailed reference viewed: 19 (5 ULg)
Has the fight against international terrorism undermined European data protection standards? A special regard to the perspectives of the transatlantic relationship
Doctoral thesis (2013)
Il s’agit d'une analyse des accords PNR (Passenger Name Records) entre l’Union Européenne et les Etats Unis et plus en général des changements aux lois de protection de la vie privée qui sont intervenus ... [more ▼]
Il s’agit d'une analyse des accords PNR (Passenger Name Records) entre l’Union Européenne et les Etats Unis et plus en général des changements aux lois de protection de la vie privée qui sont intervenus dans les dernières années, surtout à la suite des événements du onze septembre 2001. La réflexion porte donc sur l’évolution du concept de protection des données personnelles vis à vis des nouveaux instruments de collecte d’informations et d’enquête. [less ▲]Detailed reference viewed: 36 (7 ULg)
Has the final countdown to wildlife extinction in Northern Central African Republic begun ?
Bouché, Philippe ; ; Lejeune, Philippe et al
in African Journal of Ecology (2010), 48(4), 1-10
The wildlife populations of Northern Central African Republic experienced precipitous declines during the 1970s and 1980s. While anecdotes coming out of the region indicate that the wildlife populations ... [more ▼]
The wildlife populations of Northern Central African Republic experienced precipitous declines during the 1970s and 1980s. While anecdotes coming out of the region indicate that the wildlife populations remain under serious threat, little is known about their status. An aerial sample count was carried out in the Northern Central African Republic at the end of the dry season in June 2005 and covered an 85,000 km2 complex landscape containing national parks, hunting reserves and community hunting areas. Results show a dramatic decline of wildlife since the previous survey in 1985. In 20 years, large mammals’ numbers decreased by 65%, probably <br />because of poaching and diseases brought by illegal cattle transhumance. Elephant (Loxodonta africana) and Buffon kob (Kobus kob) populations showed the greatest decline (over 80% each), while buffalo (Syncerus caffer), roan antelope (Hippotragus equinus) and Giant Lord’s Derby Eland (Taurotragus derbianus) populations seem stable or increasing over these last 20 years. The analysis of the wildlife population distribution by status of the different types of protected areas (national parks, hunting areas) showed that individual encounter rates of elephant and buffalo were lower in national parks than in neighbouring hunting areas, while those for roan, giraffe (Giraffa camelopardalis) and Buffon kob were higher in the national parks. [less ▲]Detailed reference viewed: 179 (62 ULg)
Has the world economy reached its globalization limit?
; Ausloos, Marcel
in Physica A: Statistical Mechanics and its Applications (2010), 389(4), 797-806
The economy globalization measure problem is discussed. Four macroeconomic indices of twenty among the "richest" countries are examined. Four types of "distances" are calculated. Two types of networks are ... [more ▼]
The economy globalization measure problem is discussed. Four macroeconomic indices of twenty among the "richest" countries are examined. Four types of "distances" are calculated. Two types of networks are next constructed for each distance measure definition. It is shown that the globalization process can be best characterised by an entropy measure, based on entropy Manhattan distance. It is observed that a globalization maximum was reached during the interval 1970-2000. More recently a deglobalization process has been observed. (C) 2009 Elsevier B.V. All rights reserved. [less ▲]Detailed reference viewed: 4 (0 ULg)
Hasard. Der Spieler in der deutschsprachigen Literaturgeschichte.
Gerrekens, Louis ; Küpper, Achim
Book published by Königshausen & Neumann (2012)Detailed reference viewed: 24 (9 ULg)
Hasselbachtal, the section best displaying the Devonian-Carboniferous Boundary beds in the Rhenish Massif (Rheinisches Schifergebirge).
; ; et al
in Courier Forschungsinstitut Senckenberg (1984), 67Detailed reference viewed: 8 (0 ULg)
Hâtez-vous lentement, et sans perdre courage. Vingt fois sur le métier remettez votre ouvrage... - l'exemple de la réforme de l'impôt des non-résidents par la loi du 13 décembre 2012
in Tijdschrift voor Fiscaal Recht (2013)Detailed reference viewed: 24 (1 ULg)
Haubanage et gestion du risque: possibilités et limites des méthodes appliquées actuellement en Wallonie.
Campanella, Bruno ; Dumont, Benjamin
Conference (2010, June 03)
Cette présentation orale avait pour objectif de ressituer le haubanage des arbres dans le cadre général de la gestion des risques et de présenter les résultats de recherches dans ce domaine. L ... [more ▼]
Cette présentation orale avait pour objectif de ressituer le haubanage des arbres dans le cadre général de la gestion des risques et de présenter les résultats de recherches dans ce domaine. L'amortissement des mouvements de branches, notamment, a été étudié avec et sans haubans. Les liens entre contraintes mécaniques et conditions de vent ont également été mesurés. [less ▲]Detailed reference viewed: 34 (4 ULg)
Haussmann et Phèdre. L'abolition de la distinction privé/public dans l'imaginaire de l'espace des Rougon-Macquart
Master's dissertation (1996)Detailed reference viewed: 17 (1 ULg)