Buckling Cascade of Thin Plates: Forms, Constraints and Similarity

We experimentally study compression of thin plates in rectangular boxes with variable height. A cascade of buckling is generated. It gives rise to a self-similar evolution of elastic reaction of plates with box height which surprisingly exhibits repetitive vanishing and negative stiffness. These features are understood from properties of Euler's equation for elastica

Évaluation de l'écocompatibilité de déchets mis en dépôts ou valorisés en travaux publics : une méthode pluridisciplinaire pour une approche " en scénario"

Fondée sur le concept de l'écocompatibilité des déchets et élaborée à l'issue d'un programme de recherche de 5 ans, la méthode présentée nécessite une étroite collaboration entre chercheurs ou experts provenant de disciplines variées (physico-chimie, hydrogéologie, géotechnique, biologie, microbiologie,...) et travaillant sur divers milieux (déchets, sol de surface, sous-sol et eau). Elle comprend une procédure d'évaluation stricto sensu, suivie d'une procédure de décision au cours de laquelle on se prononce sur l'écocompatibilité (ou non) des scénarios de stockage ou de valorisation des déchets étudiés (ex : valorisation en technique routière). L'évaluation est effectuée selon une approche dite " en scénario ", inspirée de la norme expérimentale européenne ENV 12 920 " Caractérisation des déchets - Méthodologie pour la détermination du comportement à la lixiviation d'un déchet dans des conditions spécifiées ". Elle repose sur l'étude successive des flux de polluants émis par le dépôt ou l'ouvrage contenant les déchets (terme source), du transport de ces flux vers les milieux récepteurs (terme transport) et de l'impact des flux de polluants atteignant les milieux récepteurs (terme impact). Elle comprend une étape préalable d'analyse visant à décrire finement chacun de ces trois termes fondamentaux (source, transport et impact), de manière à identifier et à hiérarchiser les différents paramètres ayant une influence déterminante sur leur comportement. Cette analyse, qui correspond à la description du déchet et du scénario de stockage ou de valorisation des déchets, permet ensuite d'effectuer une sélection pertinente des essais à mettre en œuvre pour procéder à l'évaluation de chacun des trois termes et donc de l'écocompatibilité du scénario étudié. Les grands principes de la méthode et les principaux résultats obtenus lors du programme relatif à sa mise au point ayant fait l'objet de précédentes publications, le présent document porte sur le caractère fondamentalement pluridisciplinaire de l'application de cette méthode.The disposal and reuse of waste (e.g., reuse of waste material for civil engineering or construction) are subjected to regulations that are mainly based on the best available technologies. They usually do not directly take into account the impact on human health and on the environment due to a lack of technical data in this field. Recent emphasis on the need to evaluate this impact has resulted in the necessity for new evaluation tools.The ADEME (the French Agency for Environment and Energy Management) launched a research programme in 1995 called "Waste Ecocompatibility" to define a reliable methodology for measuring the impact of waste storage or reuse scenarios. This method could be used as a decision tool for environmental policy makers. It can also be used to determine what the acceptable levels of waste dumping or waste-based civil works are, while still being ecocompatible. The approach to set up this methodology is based on the concept of ecocompatibility. This is now defined as the situation where the pollutant flux from waste, either disposed of or reused, under specified conditions (physical, hydrogeological, chemical and biological conditions), is compatible with the environmental acceptance of the concerned receptor mediums. This definition integrates the evaluation of the pollutants emitted from the waste, the transport of these pollutants from the waste to the receptor media and their impact on the target receptor media.An introduction to the research program was proposed by Mayeux and Perrodin (1996) and Gobbey and Perrodin (1999) in previous papers. The experimental sections were taken from Barna et al. (2000a), Barna et al. (2000b) and Ferrari (2000) concerning the emission pollutant term and the assessment of waste ecotoxicological properties. Experimentation dealing with the environmental impact on the soil and aquatic media was developed by Canivet (2001) and Poly (2000). This program led to an operational methodology introduced by the ADEME (2000). The general steps in conducting the ecocompatibility assessment of waste disposal or reuse scenarios are: 1) the preliminary description of the studied scenario; 2) the implementation of tests and measurements; and 3) the assessment of the global waste scenario ecocompatibility.Ecocompatibility assessment is a multidisciplinary approach requiring researchers in biology, ecotoxicology, ecology, chemistry, hydrogeology, geology, etc. Some of them are specialists in the study of waste characterisation and waste leaching behaviour, especially with respect to investigations on long-term predictions. Researchers in charge of the impact term are skilled in the environmental impact assessment of complex effluents on soil, plants, micro-organisms, soil fauna and benthic invertebrates. In this paper, we stress the critical role of the scientific manager in the multidisciplinary work of an ecocompatibility assessment. The scientific manager must make the general problems understandable for each researcher involved. It is necessary to translate the general question into a series of specific questions related to each term of the methodology. To take advantage of a multidisciplinary study it is necessary to encourage and facilitate communication and discussion. If this is not efficient, each team will focus on its specific objective without taken into account data from the other teams. A lack of effective interactions between the involved researchers and the scientific manager will lead to a series of individual studies that are not of interest with regards to the general question. Similarly, it is essential that the various results lead to a joint discussion to draw a common conclusion

Seafloor seismicity, Antarctic ice-sounds, cetacean vocalizations and long-term ambient sound in the Indian Ocean basin

This paper presents the results from the Deflo-hydroacoustic experiment in the Southern Indian Ocean using three autonomous underwater hydrophones, complemented by two permanent hydroacoustic stations. The array monitored for 14 months, from November 2006 to December 2007, a 3000 x 3000 km wide area, encompassing large segments of the three Indian spreading ridges that meet at the Indian Triple Junction. A catalogue of 11 105 acoustic events is derived from the recorded data, of which 55 per cent are located from three hydrophones, 38 per cent from 4, 6 per cent from five and less than 1 per cent by six hydrophones. From a comparison with land-based seismic catalogues, the smallest detected earthquakes are m[subscript]b 2.6 in size, the range of recorded magnitudes is about twice that of land-based networks and the number of detected events is 5-16 times larger. Seismicity patterns vary between the three spreading ridges, with activity mainly focused on transform faults along the fast spreading Southeast Indian Ridge and more evenly distributed along spreading segments and transforms on the slow spreading Central and ultra-slow spreading Southwest Indian ridges; the Central Indian Ridge is the most active of the three with an average of 1.9 events/100 km/month. Along the Sunda Trench, acoustic events mostly radiate from the inner wall of the trench and show a 200-km-long seismic gap between 2 °S and the Equator. The array also detected more than 3600 cryogenic events, with different seasonal trends observed for events from the Antarctic margin, compared to those from drifting icebergs at lower (up to 50°S) latitudes. Vocalizations of five species and subspecies of large baleen whales were also observed and exhibit clear seasonal variability. On the three autonomous hydrophones, whale vocalizations dominate sound levels in the 20-30 and 100 Hz frequency bands, whereas earthquakes and ice tremor are a dominant source of ambient sound at frequencies < 20 Hz.Keywords: Mid-ocean ridge processes, Indian Ocean, Hydrogeophysics, Acoustic propertie

The British Lexicon Project: Lexical decision data for 28,730 monosyllabic and disyllabic English words

We present a new database of lexical decision times for English words and nonwords, for which two groups of British participants each responded to 14,365 monosyllabic and disyllabic words and the same number of nonwords for a total duration of 16 h (divided over multiple sessions). This database, called the British Lexicon Project (BLP), fills an important gap between the Dutch Lexicon Project (DLP; Keuleers, Diependaele, & Brysbaert, Frontiers in Language Sciences. Psychology, 1, 174, 2010) and the English Lexicon Project (ELP; Balota et al., 2007), because it applies the repeated measures design of the DLP to the English language. The high correlation between the BLP and ELP data indicates that a high percentage of variance in lexical decision data sets is systematic variance, rather than noise, and that the results of megastudies are rather robust with respect to the selection and presentation of the stimuli. Because of its design, the BLP makes the same analyses possible as the DLP, offering researchers with a new interesting data set of word-processing times for mixed effects analyses and mathematical modeling. The BLP data are available at http://crr.ugent.be/blp and as Electronic Supplementary Materials

Rectal Transmission of Transmitted/Founder HIV-1 Is Efficiently Prevented by Topical 1% Tenofovir in BLT Humanized Mice

Rectal microbicides are being developed to prevent new HIV infections in both men and women. We focused our in vivo preclinical efficacy study on rectally-applied tenofovir. BLT humanized mice (n = 43) were rectally inoculated with either the primary isolate HIV-1(JRCSF) or the MSM-derived transmitted/founder (T/F) virus HIV-1(THRO) within 30 minutes following treatment with topical 1% tenofovir or vehicle. Under our experimental conditions, in the absence of drug treatment we observed 50% and 60% rectal transmission by HIV-1(JRCSF) and HIV-1(THRO), respectively. Topical tenofovir reduced rectal transmission to 8% (1/12; log rank p = 0.03) for HIV-1(JRCSF) and 0% (0/6; log rank p = 0.02) for HIV-1(THRO). This is the first demonstration that any human T/F HIV-1 rectally infects humanized mice and that transmission of the T/F virus can be efficiently blocked by rectally applied 1% tenofovir. These results obtained in BLT mice, along with recent ex vivo, Phase 1 trial and non-human primate reports, provide a critically important step forward in the development of tenofovir-based rectal microbicides