How can ten fingers shape a pot? Evidence for equivalent function in culturally distinct motor skills

Behavioural variability is likely to emerge when a particular task is performed in different cultural settings, assuming that part of human motor behaviour is influenced by culture. In analysing motor behaviour it is useful to distinguish how the action is performed from the result achieved. Does cultural environment lead to specific cultural motor skills? Are there differences between cultures both in the skills themselves and in the corresponding outcomes? Here we analyse the skill of pottery wheel-throwing in French and Indian cultural environments. Our specific goal was to examine the ability of expert potters from distinct cultural settings to reproduce a common model shape (a sphere). The operational aspects of motor performance were captured through the analysis of the hand positions used by the potters during the fashioning process. In parallel, the outcomes were captured by the geometrical characteristics of the vessels produced. As expected, results revealed a cultural influence on the operational aspects of the potters' motor skill. Yet, the marked cultural differences in hand positions used did not give rise to noticeable differences in the shapes of the vessels produced. Hence, for the simple model form studied, the culturally-specific motor traditions of the French and Indian potters gave rise to an equivalent outcome, that is shape uniformity. Further work is needed to test whether such equivalence is also observed in more complex ceramic shapes

Adsorption in non interconnected pores open at one or at both ends: A reconsideration of the origin of the hysteresis phenomenon

We report on an experimental study of adsorption isotherme of nitrogen onto porous silicon with non interconnected pores open at one or at both ends in order to check for the first time the old (1938) but always current idea based on Cohan's description which suggests that the adsorption of gaz should occur reversibly in the first case and irreversibly in the second one. Hysteresis loops, the shape of which is usually associated to interconnections in porous media, are observed whether the pores are open at one or at both ends in contradiction with Cohan's model.Comment: 5 pages, 4 EPS figure

Toepasssing van Aquanox in de glastuinbouw

Wageningen UR Glastuinbouw heeft samen met Reinders Vernevelings- en Ontsmettingstechniek het project uitgevoerd naar Toepassingen van Aquanox in de glastuinbouw. Gefinancierd door Productschap Tuinbouw en Ministerie EL&I. Screeningstesten onder laboratoriumcondities geven aan dat er een brede werking is tegen schimmels en bacteriën. Virusdeeltjes in plantensap werden echter nog onvoldoende gedood door geactiveerd water. Screening van het gedrag van insecten op overleving na 24 uur in een vernevelingsbehandeling met Aquanox gaf geen doding op natuurlijke plaagbestrijders. Een lichte bestrijdende werking werd gevonden op witte vlieg, spintmijt en Californische trips. De proeven met tomaat, komkommer, roos, Poinsettia en gerbera geven aan dat er een bestrijdend effect is van geactiveerd water tegen echte meeldauw en Botrytis. Het vervolgonderzoek zal gericht zijn op vermindering van corrosierisico’s en vermindering van risico op gewasschade binnen diverse toepassingen in de teel

Bestrijding van rouwmuggen en oevervliegen

Rouwmuggen zijn zeer algemeen in kassen, en meestal talrijker dan de typische plaag-insecten. De meeste soorten voeden zich met schimmels en met organisch materiaal, en zijn onschadelijke voor planten. Enkele soorten kunnen schadelijk zijn in zaaibedden, aan stekmateriaal en aan jonge planten. Veel breedwerkende insecticiden hebben een effect op de muggen en hun larven, maar het probleem blijft dat de populaties zich echter snel herstellen. Van de twintig geteste producten gaven Trigard (cyromazine), Nomolt (teflubenzuron) en de nematode Steinernema feltiae de beste resultaten. Geen van de insectenpathogene schimmels en ook niet de kortschildkever Atheta coriaria en de nematode Heterorhabditis bacteriophora hadden effect op het aantal rouwmuggen. Bodemroofmijten waren op korte termijn niet effectief

Adsorption-Induced Deformation in Nanopores: Unexpected Results Obtained by Molecular Simulations

International audienceThe adsorption of a fluid in a nanoporous material induces deformations of the solid. The saturating regime, where the solid is filled with liquid, generally exhibits a linear relationship between the liquid pressure and the solid strain. This provides an experimental way to measure the elastic moduli of the solid walls. For large pores, the strain is determined by the pressure of the liquid saturating the pores and the mechanical properties of the porous solid. What happens at the nanometric scale, where liquid/matrix interfacial effects dominate? We have performed molecular simulations of a simple Lennard-Jones fluid confined between deformable nanoplatelets. The simulations provide the deformation of the nanopore as a function of the liquid pressure, in a way similar to what is done experimentally. The results show unexpected interface effects, which could be relevant to experimental data analysis

Advanced calibration of a 3D masonry arch bridge model using non-destructive testing and numerical optimisation

Historical masonry arch bridges constitute the backbone of many existing transportation networks in different countries in Europe and worldwide. They represent valuable cultural heritage assets and play an essential social and economic role. Since construction, old masonry bridges have accumulated structural damage from traffic and environmental actions. Furthermore, depending on their geometrical and mechanical characteristics, they may be particularly vulnerable to extreme events like earthquakes. Thus, accurate structural assessment under different loading conditions is critical for the conservation of these structures. Realistic assessment requires suitable numerical models to represent the characteristic 3D behaviour. The complexity of this task is further compounded by the practical difficulty in obtaining essential information on the internal bridge structure and the masonry mechanical parameters, which are vital to achieve accurate response predictions against service and extreme actions. This paper presents an advanced calibration procedure for a refined macroscale bridge model, allowing for the anisotropic nature of the masonry material. The proposed calibration approach is applied to an actual multi-span masonry viaduct, where sonic, ultrasonic, and ground penetrating radar tests are conducted to investigate the internal structure of the viaduct and determine the elastic properties of the masonry materials. In addition, the dynamic characteristics of the bridge are evaluated through in-situ measurements under environmental vibrations and used for model validation. The results from a standard simplified model calibration and an enhanced calibration are compared considering the vibration modes of the bridge. Simplified calibration is carried out using the results from in-situ tests, while a statistic inference procedure and numerical optimisation are adopted in the refined calibration to achieve improved accuracy. Although the paper focuses on a specific case study, the adopted methodology can be easily applied to studying other masonry bridges and cultural heritage masonry structures