The ECORS-Truc Vert’08 nearshore field experiment: presentation of a three-dimensional morphologic system in a macro-tidal environment during consecutive extreme storm conditions

A large multi-institutional nearshore field experiment was conducted at Truc Vert, on the Atlantic coast of France in early 2008. Truc Vert’08 was designed to measure beach change on a long, sandy stretch of coast without engineering works with emphasis on large winter waves (offshore significant wave height up to 8 m), a three-dimensional morphology, and macro-tidal conditions. Nearshore wave transformation, circulation and bathymetric changes involve coupled processes at many spatial and temporal scales thus implying the need to improve our knowledge for the full spectrum of scales to achieve a comprehensive view of the natural system. This experiment is unique when compared with existing experiments because of the simultaneous investigation of processes at different scales, both spatially (from ripples to sand banks) and temporally (from single swash events to several spring-neap tidal cycles, including a major storm event). The purpose of this paper is to provide background information on the experiment by providing detailed presentation of the instrument layout and snapshots of preliminary results.     

Allometric relations between fluvial impulse and morphometric parameters of floodplain lakes

The general role of river water input in shaping the basic morphometric parameters of floodplain lakes has been previously investigated. However, the process has not been quantitatively described in detail. This study is the first attempt in the literature to determine the allometric relation between fluvial impulse, expressed as Fluvial Connectivity Quotient, and morphometric parameters of six floodplain lakes of Bug River valley in the period 1952–2014. This relationship is given by Y = aX^b, from which the value of b exponent was analysed to determine the strength of the allometric relation. Extreme values of allometric compounds during the time period under study ranged from 5.99 to ?4.91. Volume was the morphometric parameter showing the highest variability in all the lakes. General similarity in allometric relations was observed in the lakes under study. During analysis, no long‐term trends were observed in the relationship between the Fluvial Connectivity Quotient and morphometric parameters. The results obtained show that fluvial impulse was the factor determining the variability of morphometric parameters of the lakes. Direct catchments topography of lake has periodically (during limnophase periods) played a significant role in shaping the morphometry of floodplain lakes. The most stable allometric relations occurred in a confluent lake, with a low limnological effective rise value and consequently, relatively long potamophase periods.Copyright © 2015 John Wiley & Sons, Ltd.     

European Venus Explorer (EVE): an in-situ mission to Venus

The European Venus Explorer (EVE) mission was proposed to the European Space Agency in 2007, as an M-class mission under the Cosmic Vision Programme. Although it has not been chosen in the 2007 selection round for programmatic reasons, the EVE mission may serve as a useful reference point for future missions, so it is described here. It consists of one balloon platform floating at an altitude of 50–60 km, one descent probe provided by Russia, and an orbiter with a polar orbit which will relay data from the balloon and descent probe, and perform science observations. The balloon type preferred for scientific goals is one which oscillates in altitude through the cloud deck. To achieve this flight profile, the balloon envelope contains a phase change fluid, which results in a flight profile which oscillates in height. The nominal balloon lifetime is 7 days—enough for one full circumnavigation of the planet. The descent probe’s fall through the atmosphere takes 60 min, followed by 30 min of operation on the surface. The key measurement objectives of EVE are: (1) in situ measurement from the balloon of noble gas abundances and stable isotope ratios, to study the record of the evolution of Venus; (2) in situ balloon-borne measurement of cloud particle and gas composition, and their spatial variation, to understand the complex cloud-level chemistry; (3) in situ measurements of environmental parameters and winds (from tracking of the balloon) for one rotation around the planet, to understand atmospheric dynamics and radiative balance in this crucial region. The portfolio of key measurements is complemented by the Russian descent probe, which enables the investigation of the deep atmosphere and surface.     

Derivatives of silicic acids as model compounds for silicates

Silicon-29 chemical shifts of methyl, ethyl, chloro and trimethylsilyl derivatives of silicic acids are compared to those of silicic acid anions found in aqueous solutions. Although the chemical shifts of the silicate anions vary with pH and concentration, a good correlation is obtained for the chloro and alkoxi derivatives. The chemical shifts of the trimethylsilyl esters are of limited comparability to the data of the silicates only.     

Die häufigsten Cyanophyceen der Litoralzone in Seen mit verschiedenem Kalkgehalt

Ohne Zusammenfassung     

The photospheric barium spectrum: Solar abundance and collision broadening of Baii lines by hydrogen

A study of the solar Ba ii spectrum leads to a solar abundance of barium of log ba = = 2.11±0.12, on the scale log h = 12. The observed asymmetry of the resonance line 4554 is consistent with an isotopic abundance ratio equal to the terrestrial one. The meteoritic Ba/Si abundance ratio found in carbonaceous chondrites appears to exceed the solar ratio by 0.1 to 0.2 dex (Section 5).The broadening by collisions with hydrogen atoms is determined from the solar spectrum (Section 4). Damping half-widths, h, of the three stronger Ba ii lines turn out to be larger by a factor of about 3.0 than predicted from pure van der Waals interaction of dipoles. Departures from LTE appear to be present in the cores of the resonance lines and of the lines arising from the metastable 5D levels (Section 6). The equivalent widths, however, remain practically unaffected.Equivalent widths of neutral barium lines are predicted and some new identifications of photospheric Ba i lines are suggested (Section 7).     

Structure of Molecular Clouds

This review, far from exhaustive, focuses on the specific properties of molecular clouds in their least condensed phase. Emphasis is placed on their connection with the diffuse medium, their multi-fractal characteristics and the diversity of their small-scale structure, where cold and dense gas may coexist with dilute and warm gas. Stuctures of essentially pure velocity origin are uncovered and seen as a possible signature of the intermittency of turbulence dissipation.     

In situ and nondestructive characterization of mechanical properties of heritage stone masonry

The necessity of conserving and preserving the heritage is nowadays a developing study line for several researchers. From a civil engineering perspective, one of the most important issues for the conservation of historical buildings is to ensure the structural stability. For this purpose, it is necessary to determine the mechanical properties of the ancient construction materials. However, these structures cannot be evaluated by destructive tests due to politics and restrictions for preserving the heritage built. As a consequence, new methods that do not put in risk the integrity of the materials and the structure are becoming useful tools for researchers who work on structural engineering of heritage buildings. This paper presents a nondestructive method (NDM) that has been used to characterize the mechanical properties of different constructive systems of the San Antonio de Padua Temple, which is a religious icon in Aguascalientes, Mexico. This method includes the measuring of seismic waves’ travel time in order to obtain shear and compressional velocity waves. Results show that with this method mechanical properties of masonry can be obtained such as Young’s modulus, Poisson ratio and bulk density, which are needed for the structural analysis using numerical simulation models.