14th International Benchmark Workshop on Numerical Analysis of Dams

The Janneh dam is a 162-meter high Roller Compacted Concrete arch-gravity dam under construction in the Nahr Ibrahim Valley of Lebanon. The impounded reservoir will supply water, irrigate agricultural areas and generate hydropower . The dam will serve the Northern areas of Greater Beirut Mount Lebanon . The project site is located in high- seismicity region. The Peak Ground Accelerations are 0.37g and 0.51g respectively for OBE and SEE. Under favorable conditions (shape of the valley, strength of the bedrock, availability of construction materials), the construction of an arch-gravity dam is a more and more interesting alternative. The construction stages are simulated in ABAQUS environment in order to perform both linear and non-linear analyses

Estimates of new and total productivity in central Long Island Sound from in situ measurements of nitrate and dissolved oxygen

Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Estuaries and Coasts 36 (2013): 74-97, doi:10.1007/s12237-012-9560-5.Biogeochemical cycles in estuaries are regulated by a diverse set of physical and biological variables that operate over a variety of time scales. Using in situ optical sensors, we conducted a high-frequency time-series study of several biogeochemical parameters at a mooring in central Long Island Sound from May to August 2010. During this period, we documented well-defined diel cycles in nitrate concentration that were correlated to dissolved oxygen, wind stress, tidal mixing, and irradiance. By filtering the data to separate the nitrate time series into various signal components, we estimated the amount of variation that could be ascribed to each process. Primary production and surface wind stress explained 59% and 19%, respectively, of the variation in nitrate concentrations. Less frequent physical forcings, including large-magnitude wind events and spring tides, served to decouple the relationship between oxygen, nitrate, and sunlight on about one-quarter of study days. Daytime nitrate minima and dissolved oxygen maxima occurred nearly simultaneously on the majority (> 80%) of days during the study period; both were strongly correlated with the daily peak in irradiance. Nighttime nitrate maxima reflected a pattern in which surface-layer stocks were depleted each afternoon and recharged the following night. Changes in nitrate concentrations were used to generate daily estimates of new primary production (182 ± 37 mg C m-2 d-1) and the f-ratio (0.25), i.e., the ratio of production based on nitrate to total production. These estimates, the first of their kind in Long Island Sound, were compared to values of community respiration, primary productivity, and net ecosystem metabolism, which were derived from in situ measurements of oxygen concentration. Daily averages of the three metabolic parameters were 1660 ± 431, 2080 ± 419, and 429 ± 203 mg C m-2 d-1, respectively. While the system remained weakly autotrophic over the duration of the study period, we observed very large day-to-day differences in the f-ratio and in the various metabolic parameters.This work was supported by the Yale Institute for Biospheric Studies, the Sounds Conservancy of the Quebec-Labrador Foundation, and the Yale School of Forestry and Environmental Studies Carpenter-Sperry Fund.2014-01-0

Ecology of Marine Protozoa

viii,366 hal,;ill,;29 c

Insulin modulation of ATP-sensitive K+ channel of rat skeletal muscle is impaired in the hypokalaemic state

In the present work, we examined the effects of in vivo administration of insulin to rats made hypokalaemic by feeding a K+-free diet. The i.p. injection of insulin in the hypokalaemic rats provoked muscle paralysis within 3-5 h. Consistent with this observation, the skeletal muscle fibres of the paralysed rats were depolarized. In contrast, in the normokalaemic animals, insulin neither provoked paralysis nor produced significant fibre hyperpolarization. In the hypokalaemic rats, insulin almost completely abolished the sarcolemma adenosine triphosphate (ATP)-sensitive K+ currents without altering the sensitivity of the channels to ATP or glibenclamide. In contrast, in the normokalaemic rats, insulin enhanced ATP-sensitive K+ currents that became also resistant to ATP and glibenclamide. Our experiments indicate that the modulation of the sarcolemma ATP-sensitive K+ channels by insulin is impaired in the hypokalaemic state. This phenomenon appears to be related to the fibre depolarization and paralysis observed in the same animals

Static and seismic analysis of an arch-gravity dam

The Janneh dam is a 162-meter high Roller Compacted Concrete arch-gravity dam under construction in the Nahr Ibrahim Valley of Lebanon. The impounded reservoir will supply water, irrigate agricultural areas and generate hydro-power . The dam will serve the Northern areas of Greater Beirut Mount Lebanon . The project site is located in high- seismicity region. The Peak Ground Accelerations are 0.37g and 0.51g respectively for OBE and SEE. Under favorable conditions (shape of the valley, strength of the bedrock, availability of construction materials), the construction of an arch-gravity dam is a more and more interesting alternative. The construction stages are simulated in ABAQUS environment in order to perform both linear and non-linear analysis

A compression-shear fracture growing on an arch-gravity dam

In the case of a narrow valley, characterized by a strong rock mass, the excavation can be designed according to the so called convergent way. In this case, the mean value of the compression stresses at the dam-foundation joint increases as the dam moves towards down-stream under the action of the water pressure applied to the up-stream side. During this slip settlement, the stress level in both materials, concrete and rock, remains allowable. It is true that the seismic load is able to increase such a slip displacement, nevertheless, since the structure is designed for horizontal hydrostatic loads, the stress level remains allowable even in such a seismic condition. The above mentioned issue was discussed during the 14th Benchmark Workshop on the Numerical Analysis of Dams organized by the International Commission on Large Dams (Stockholm, 6–9 September 2017). The theme B of the above mentioned Workshop was the static and seismic analysis of the Janneh dam. It is an arc-gravity dam, 157 meters high, now under construction in Lebanon, a high-seismicity region. The ten participants compared their results, obtained independently from each other and through different numerical models. In this paper the contribution of the authors is presented and the mechanical hypotheses at the base of the three-dimensional evolution of the crack path, at the dam-foundation joint, are discussed

Involvement of K(Ca2+)channels in the local abnormalities and hyperkalemia following the ischemia-reperfusion injury of rat skeletal muscle

Patch-clamp technique was used to investigate the proper-ties of the muscular Ca2+-activated K+ channel (KCa2+) in the ischemic and ischemic-reperfused rat muscle fibers and the possible involvement of this ion channel in the reperfusion-dependent hyperkalemic state. The properties of the muscular KCa2+ channel were unaltered following 4 h of ischemia of the lower limbs and that the serum K+ level did not change following ischemia. In contrast, after 3 h of reperfusion an over-activation of KCa2+ channel was observed which was related to the increase in the number of functional channels per patch area. Currents from cation aselective channels were also routinely detected in these muscles and ion channel abnormalities similar to those observed in the ischemic-reperfused muscles were also found in the contralateral muscles. Significant hyperkalemia was observed following 3 h of reperfusion. Administration of L-NAME (10 mg.kg(-1)), a nitric-oxide synthase (NOS) inhibitor, during reperfusion prevented the increase of KCa2+ channel activity and the activation of the cation aselective channel. The L-NAME treatment also partially antagonised the characteristic hyperkalemia observed following reperfusion. In contrast, D-NAME (20 mg.kg(-1)), the inactive antipode on NOS enzyme administered to the rats during reperfusion failed to prevent the overactivation of the KCa2+ channel or the hyperkalemia. Our results indicate that overactivation of KCa2+ channel found in the muscles following reperfusion is either directly or indirectly related to NOS activation, and contributes to the hyperkalemia. Moreover, the discovery of abnormalities similar to those of the ischemic-reperfused muscles in the contralaterals suggests that proinflammatory molecules were released from the ischemic area, accentuating the pathological state