Thermal conductivity through the nineteenth century

As a material property and as a metaphor, thermal conductivity occupies an important position in physical, biological and geological sciences. Yet, its precise measurement is dependent on using electricity as a proxy because flowing heat cannot directly be measured.Comment: Submitted to Physics Today. 4,500 words, 4 figure

Face or building superiority in peripheral vision reversed by task requirements

Peripheral vision has been the topic of few studies compared with central vision. Nevertheless, given that visual information covers all the visual field and that relevant information can originate from highly eccentric positions, the understanding of peripheral vision abilities for object perception seems essential. The poorer resolution of peripheral vision would first suggest that objects requiring large-scale feature integration such as buildings would be better processed than objects requiring finer analysis such as faces. Nevertheless, task requirements also determine the information (coarse or fine) necessary for a given object to be processed. We therefore investigated how task and eccentricity modulate object processing in peripheral vision. Three experiments were carried out requiring finer or coarser information processing of faces and buildings presented in central and peripheral vision. Our results showed that buildings were better judged as identical or familiar in periphery whilst faces were better categorised. We conclude that this superiority for a given stimulus in peripheral vision results (a) from the available information, which depends on the decrease of resolution with eccentricity, and (b) from the useful information, which depends on both the task and the semantic category

Le système manorial d'agriculture au 14e siècle en Angleterre

The centre of the manorial system was the manor whose major function was of a judicial order. Its court set the rules of organization of the open-field. On the manor, the passants bore different names : «villeins», «nativi», «neifs», «virga- ters», «demi-virgaters» tended their own land and next to them one found «liberi homines». Everything rested on the productivity of ploughing. For the tenant- farmers and the servants of the estate ploughing was the most important corvee. The system started to decay with the Black Plague and the manorial tenant- farmers' corvées progressively disappeared. The change took place earlier in the south than in the rest of the country.Le centre du système manorial était le manoir dont la fonction principale était d'ordre judiciaire. Sa cour fixait les règles d'organisation de l'open-field. Sur le manoir les paysans portaient des noms différents : villeins, nativi, neifs, virgaters, demi-virgaters, acremen, bordiers, cottiers. Virgaters ou demi-virgaters exploitaient leur propre terre et à côté d'eux on rencontrait des liberi homines. Tout reposait sur la productivité des labours. Pour les tenanciers et les domestiques du domaine les labours étaient la corvée la plus importante. Le système périclita avec la Peste Noire et les corvées des tenanciers manoriaux disparurent progressivement. Le changement s'opéra plus vite dans le sud qu'ailleurs.Het centrum van het pachtsysteem was de heerlijkheid met, vooral, een bevoegdheid op rechtskundig gebied. Het hof bepaalde het règlement voor het open field. Op het pachthof droegen de boeren verschillende namen : villeins, nativei, neifs, virgaters, half-virgaters, acremen, bordiers en cottiers (pachters). De virgaters en half-virgaters bewerkten hun eigen grond en men treft daarnaast liberi homines aan. De grondslag was de produktiviteit van de ploeger, wat ook de voornaamste taak was van de onderhorigen in het domein. De Zwarte Pest bracht het einde van dis systeem mee en daarna verdween geleidelijk de herendienst van de pachters. Dit gebeurde eerder in het zuiden dan elders.Despretz Claude. Le système manorial d'agriculture au 14e siècle en Angleterre. In: Revue du Nord, tome 72, n°287, Juillet-septembre 1990. Hommage à Guy Fourquin. pp. 483-493