Six glacial cover maps of Cordillera Blanca in Peru were prepared using the band ratio (TM4/TM5) of Landsat 5 TM, ETM+4/ ETM+5 of Landsat 7 ETM+ and OLI5/OLI 61 of Landsat 8 images. This cover varied between 618±60 km2 in 1987 and 449±56 km2 in 2016. In spite of differences in mapping methodologies, our glacial cover estimates are comparable with those of other studies, given an uncertainty margin of around ± 10 %. Since 1930, when the glaciers covered ca. 830 km2, the Cordillera Blanca has lost 46 % of its cover in 86 years. A nonlinear-, second-degree polynomial has been fitted to the glacier cover evolution overtime, showing that the negative rate of change has increased between the 80’s (5 km2 y-1) and 2016 (23 km2 y-1). Considering altitude, the decrease in cover is particularly notable between 4500-5000 m and 5000-5500 m, and changes in the latter altitude are becoming more dominant over time (over 60 %). To explain the minor fluctuations in glacier cover around the global trend, the yearly rate of cover change was regressed against the mean Oceanic Nino Index for six periods between 1987 and 2016. The inverse relationship shows a certain amount of dispersion, that has yet to be explained, but is nonetheless significant. Keywords : remote sensing; Landsat; Snow index; band ratio; Andes; climate change; glaciology; El Nino/La Nina.
Cet article etudie les conditions de la decouverte naturaliste du Mont-Blanc sous l’angle des echanges de materiel entre savants. A une epoque ou les frontieres entre le champ scientifique emergent sont encore floues, et ou subsistent des connexions avec les artistes, les hommes de lettres et les nobles voyageurs, certains de ces « objets intermediaires » combinent des fonctions scientifiques, culturelles et sociales. C’est notamment le cas des illustrations de montagnes et de glaciers, malgre les efforts de Saussure pour en faire des instruments au service de la geologie. En ce qui concerne les specimens, leur fonction et leur circulation varient d’un champ de recherche a l’autre et dependant aussi des intentions et des conceptions methodologiques de chaque chercheur. Certains cabinets d’histoire naturelle conservent ainsi une fonction sociale et ostentatoire, tandis que d’autres servent a l’instruction ou a la recherche. La plupart combinent ces fonctions dans des proportions variables. Ainsi, les specimens qu’ils contiennent peuvent etre spectaculaires ou pas. Ils peuvent etre bus par des collegues ou des touristes, ou etre presentes dans les societes locales, ou encore etre stockes a des fins personnelles. Ils peuvent circuler sous la forme d’illustrations dans des cercles plus larges ou etre mentionnes par des visiteurs. Des geologues et des naturalistes peuvent etre approvisionnes en objets d’etude envoyes sous la forme de specimens, d’illustrations ou de textes. Mais cette circulation d’objet intermediaires ne peut entierement remplacer l’experience de terrain, particulierement en geologie. En fin de compte, l’article compare les ouvrages de Saussure et de Deluc, montrant que leur circulation est largement conditionnee par leurs conceptions methodologiques respectives, et par la maniere dont ils concoivent leur propre contribution scientifique.
La plate-forme carbonatee urgonienne forme l’ossature des chaines subalpines septentrionales francaises et, plus modestement, souligne la morphologie jurassienne. Sa mise en place et son evolution sont actuellement l’objet de trois modeles inconciliables concus et publies par des «ecoles » differentes: ecole de Grenoble (avec H. Arnaud et co-auteurs) pour la premiere, ecole de Neuchâtel – Lausanne (avec K. Follmi et co-auteurs) pour la deuxieme, ecole de Geneve-Lyon (representee par les auteurs ci-dessus) pour la troisieme. Le rappel historique des travaux consacres a l’«Urgonien auct. » est suivi de la presentation de notre propre modele, esquisse il y a deja une trentaine d’annees a partir des donnees biostratigraphiques fournies par les ammonites et les echinides, developpe et precise depuis par l’etude des microfossiles (orbitolinides et dasycladales notamment). Sept coupes correlees du Jura vaudois au Vercors meridional et sept autres a travers le Vivarais permettent d’etablir deux transects, qui mettent en evidence la progradation de la plate-forme urgonienne du NNE au SSW pour le premier et du SW au NE pour le second; les ammonites et microfossiles qui assurent leur cadre biostratigraphique sont figures dans 27 planches. Leurs faunes d’orbitolinides sont comparees a celles de deux coupes situees en Provence et d’une coupe representative du domaine helvetique de Suisse centrale: ces dernieres sont illustrees en 5 planches. Les divers arguments – biostratigraphiques, geochimiques, sequentiels – invoques dans les trois differents modeles seront presentes a cette occasion et leurs conclusions confrontees aux realites du terrain.
We measured Action Potentials (APs) with extracellular wet recording electrodes at a sampling rate of 10 Hz (i.e. 10 Samples per second, 10 Ss). The touch stimulation of an adult Arabidopsis thaliana (col accession) leaf elicited a transient (~10 sec) depolarization (~-50 mV) potential (AP), moving away from the excitation zone to the petiole at a speed of ~1.5 mm s-1. These numbers are in average coherent with those reported in the literature. But some works have reported ultra fast APs in the ms duration range and with m s-1 propagation speed (i.e. thousands time shorter and with propagation speeds of thousands times faster). This kind of ultra fast APs can’t be measured at 10 Ss sampling rate. We undertook here to sample our touch elicited APs in Arabidopsis at different sampling rates (i.e comparing 10 Ss and 10000 Ss simultaneously and then at 100000 Ss). It is clearly demonstrated that touch elicited plant AP cannot result from higher frequency aliasing and a 10 Ss sampling rate is sufficient for a signal with ~10 s duration. At 100000 Ss sampling rate, it was possible to eventually observe some very fast electrical events. Their duration is from 10 μs (i.e. minimum sampling interval) to 200 μs. However, they occur simultaneously on 2 distant electrodes (Leaf – petiole) without any amplitude correlation, their median amplitude is not statistically different from the null value. There are no differences between different treatments on the leaf (i.e. none, water or H2SO4). It is very likely that these very fast electrical events don’t have a biological origin. It is proposed that they are electrical interferences arising from external plant sources.
Les recents progres de la chimie analytique instrumentale (chromatographie liquide couplee a la spectrometrie de masse en tandem ; LC MS-MS) permettent de mettre en evidence plusieurs composes xenobiotiques a l’etat de trace (du ng/L a quelques centaines de ng/L) dans les eaux du Leman ainsi que dans la chair des poissons. Ces substances proviennent en partie d’un usage medical, mais egalement d’une production industrielle dans le bassin versant, de leur utilisation en agriculture (phytosanitaires) ainsi que de l’emploi quotidien de formulations qui font appel a la chimie ; agents anticorrosion, antibacteriens, hydrofuge, retardateurs de flamme, cosmetiques, etc. L’interpretation des risques environnementaux ou humains lies a la presence indesirable de ces composes est delicate du fait du peu de donnees disponibles, d’evaluations ou d’etudes dans le domaine de ces micropolluants dits « emergents ». Les filieres de traitement de 11 stations de potabilisation de l’eau du Leman sont decrites. Les resultats montrent que l’ozone et la filtration sur lits de charbons actifs sont des traitements efficaces et deviendront imperatifs, dans le futur, pour eloigner ces substances etrangeres de l’eau potable meme si la legislation actuelle ne regule que les phytosanitaires. Une veille analytique soutenue dans le bassin versant et les eaux du lac suivie d’une information au public devrait etre mise en place pour que l’instauration de traitements appropries dans les STEP conjuguee a un usage plus raisonne de ces micropolluants reduise, a l’avenir, les quantites de ces composes indesirables dans notre environnement.
L’energie thermique des lacs est de plus en plus valorisee, principalement pour repondre aux demandes croissantes de climatisation des bâtiments. A partir du retour d’experience realise sur le systeme GLN a Geneve, les effets de telles infrastructures sur le milieu lacustre ont ete etudies et les impacts ont ete evalues comme tres faibles. La generalisation de tels systemes est principalement limitee par la demande de climatisation qui restera restreinte sous nos climats, plutot que par les limites physiques de la ressource. De plus, la comparaison des impacts sur l’environnement avec la filiere energetique traditionnellement utilisee (electricite thermique et groupe de froid) se montre favorable a ce type de systeme. Une utilisation correcte de cette ressource garantissant des impacts aussi faibles que possible necessite une meilleure connaissance scientifique du systeme lacustre lui-meme.
This study assesses the presence, fate and effects of five environmentally relevant pharmaceuticals and eight of their corresponding human metabolites in Lake Geneva. Over a 10-month period, lake samples were taken at various depths and locations in the Vidy Bay. Among the targeted metabolites, six were detected with concentrations ranging from 5 to > 100 ng∙L-1. The highest concentrations were detected above the wastewater treatment plant outfall, supporting the assumption that wastewater represents the main source of human metabolites to the lake. The metabolites were less recalcitrant to environmental degradation than their parent. Nevertheless, their presence in the aquatic environment may lead to an increase of the ecotoxicological risk.
Due to dynamic compaction, the structure of loess is changed and by increasing the number of dynamic blows, the soil is involved in axial deformation. This deformation is done as collapse and strain. To 6 blows, the axial strain rate is more and after that it is decreased to achieve a constant rate. Generally, due to the blows, cracks, grains bending, the torsion of grains, the break of grains, crush of peds and grains compaction are occurred. The severity, type and amount of soil strain depend upon the number of blows and the type of soil. In loess of Golestan, three different behavior is seen.The loess collapsing due to the structure blow. The other group in which axial deformation is created and the other group show the collapse and axial deformation.
Background: Customer satisfaction is one of the key success factors to the survival of any business organization. The aim of this study is to determine the effects of service recovery on customer satisfaction. Method: A cross sectional study was carried out among students and the general public in Tehran city, Iran, data was collected using validated questionnaire adopted for this study. A total of 384 students and general public that they have bought a cell phone before was selected. Result: Among respondents 193(50.3%) were male, 212 were university degree (55.2%) and 263(68.5%) were single. The results showed that distributive justice significantly affected on the complainants’ level of satisfaction with service recovery. Trust and loyalty were affected by their satisfaction with the service recovery. Based on the T-test the levels of trust, WOM and loyalty were sharply higher for respondents who were satisfied with the service recovery compared with those who were dissatisfied. Also, respondents who were satisfied with the service said lower trust, WOM and consumer loyalty compared with the satisfied complainants. Finally, the study indicates that dissatisfied non-complainants would exhibit a lower Conclusion: The findings in this paper confirmed the importance of perceived justice in service recovery. Also, this paper is useful in designing policies and procedures to gain higher satisfaction, trust and loyalty from customer.
Francois Alphonse Forel est non seulement le fondateur de la limnologie mais aussi le premier savant a aborder de maniere globale les palafittes du Leman. Un siecle apres sa disparition, nous proposons un bref bilan des connaissances accumulees sur les occupations prehistoriques riveraines de ce lac. Au-dela d’une synthese, toujours provisoire, cette contribution est surtout l’occasion de faire le point sur les nombreuses questions encore en suspens. Les recherches recentes sur les sites littoraux lemaniques ne totalisent qu’une trentaine d’annees d’investigations et d’analyses, mais avec des moyens tres modestes par rapport a ceux engages lors des grands chantiers de sauvetage, menes des les annees soixante sur les rives du lac de Neuchâtel et de Zurich. Les quatre periodes de peuplement littoral connues sur les autres lacs du plateau suisse sont identifiees dans le Leman: le Neolithique moyen II (39e et 38e siecles av. J.-C.), le Neolithique final (30e au milieu du 27e siecle av. J.-C.), l’âge du Bronze ancien (fin du 19e siecle a fin du 17e siecle av. J.-C.) et le Bronze final (debut du 11e siecle au milieu du 9e siecle av. J.-C.). Les bas niveaux du lac, correspondants a ces occupations se distribuent entre les altitudes 367 et 372 m (au plus cinq metres de profondeur par rapport au niveau moyen actuel). Les resultats obtenus permettent de proposer quelques elements de comprehension, qui fournissent l’ebauche d’un modele de peuplement, utile pour la poursuite des recherches dans le domaine.
Before any construction of retaining structures it is important to understand the behavior of the soil and the characteristic of the failure modes involved. All this basic information is to ensure no errors happens during the design and to provide efficient and economic solution. In the knowledge of soil mechanics there are no such site will have exactly the same condition and characteristic. Form the view of engineering, soil is a unique material which is form by continuous and complex process. According to Terzhagi and Peck, soil is composing of granular aggregate particles which can be extracted by mechanical action (Craig, 1997). Different soil condition will provide different magnitude of earth pressure against the slope stability and also the retaining structure. This research will highlight various techniques related to shear strength of soil, slope failure mechanisms, common slope failure, factor influencing the slope stability and the design concept of sheet pile wall and contiguous bored pile wall.
Hydrodynamic processes in Lake Geneva (Switzerland and France) have been studied since the pioneering work of F.A. FOREL who initiated the science of limnology as a branch of oceanography. Lake Geneva is characterized by a thermal stratification of the water column from spring to autumn and a homogenization from the end of winter to the beginning of spring. Lake Geneva is a « monomictic » lake according to theclassification of Hutchison. To obtain a better understanding of the hydrodynamics of Lake Geneva, a three-dimensional finite element model with the ability to simulate the temperature structure and water movement was applied. The finite element grid superimposed on the bathymetric data has a resolution of 8149 triangular elements different size ranging from 10 to 100 meter each side and 4553 nodes, covering the two lake basins : Petit-Lac and Grand-Lac. The model was run for a period of one year (2005) with continuously updated weather data. The model solves the equations for the conservation of mass transport, dynamics and temperature, which can simulate the water temperature, current velocity and direction. The annual thermal cycle begins with isothermal conditions in winter, followed by thorough mixing in late winter, and by stratification from May to October. The annual cycle of temperature distribution in the Grand-Lac shows strong seasonal trends. Depending on the difference in volume and morphology of the basin, cooling and warming during the transition periods (spring and fall) are slower in the Grand-Lac than in the Petit-Lac. Over much of the year, the waters of Grand-Lac circulate in a gyre turning counterclockwise. The size and lifetime of the vortex varies depending on weather conditions. Appendices of the main gyre are found in major bays of the northern shore, in Morges and Vidy (Lausanne). These are less stable than the main gyre and their direction may switch depending on wind direction. In the transitional area between the Grand-Lac and the Petit-Lac a gyre oriented clockwise is established. The western end of the Petit-Lac is characterized by a counterclockwise circulation system. In the Petit-Lac, flow towards the Rhone outlet mainly occurs in surface waters and along the borders of the basin, while the return currents to the Grand-Lac are deeper-water currents and found in the central part of the basin. In the Grand-Lac, the downstream flow from East to West follows the northern edge of the basin, while the return current, from the western to the eastern part of the basin, predominantlyfollows the southern border. Results of modelling are generally in good agreement with field data ; however systematic current surveys in the different parts of the lake basin are still missing for the model validation.
Trace metals (TMs) play a central role in the functioning of aquatic systems. Both essential and toxic trace metals are involved in different chemical, biological and physical processes that determine their concentration and chemical forms. The various TM chemical form include free hydrated ions ; metal complexes with various small inorganic and organic ligands as well as with ill-defined dissolved organic matter ; metals adsorbed on the surface of natural or anthropogenic colloids and particles. TMs reactivity, fate and impact on the organisms depend on the proportion of these different forms which in turn is influenced by the biophysicochemical conditions of the media. In this overview, dedicated to the father of the modern limnology Francois-Alphonse Forel, we present current concepts of chemical speciation, sorption processes and biological availability that play a key role in metal cycling and regulation occurring in the aquatic systems. These concepts are illustrated with examples of field case studies performed in the Riou-Mort stream in France and the plume of the Po River in the Northern Adriatic Sea. The necessity of more environmental realism as well as the exciting gaps and challenges in TM cycling in the aquatic systems are also discussed.
