Pseudo-critical clusterization in nuclear multifragmentation

In this contribution we show that the biggest fragment charge distribution in central collisions of Xe+Sn leading to multifragmentation is an admixture of two asymptotic distributions observed for the lowest and highest bombarding energies. The evolution of the relative weights of the two components with bombarding energy is shown to be analogous to that observed as a function of time for the largest cluster produced in irreversible aggregation for a finite system. We infer that the size distribution of the largest fragment in nuclear multifragmentation is also characteristic of the time scale of the process, which is largely determined by the onset of radial expansion in this energy range.Comment: 4 pages, 3 figures, Contribution to conference proceedings of the 25th International Nuclear Physics Conference (INPC 2013

Mesure des durées de vie des premiers niveaux excités du molybdène 93

Les durées de vie des six premiers niveaux excités du 93Mo ont été mesurées en utilisant l'effet Doppler associé à la réaction 93Nb(p, nγ)93Mo. Deux nouvelles durées de vie ont été obtenues et la précision des quatre autres a été améliorée

Why sharecropping? : explaining its presence and absence in Europe's vineyards, 1750-1950

The traditional view that sharecropping was a cause of low productivity in European agriculture prior to the Second World War has been challenged by economic historians, and today the contact is often considered as efficient at reducing the monitoring costs associated with labour and allocation of risk between landowners and farmers, especially when capital markets were weak for working capital. Yet if sharecropping was a relatively efficient contract, why was it not found more often? This paper looks at the vine, a crop that was widespread in Europe and that has been central to the current debates. It argues that while the literature has been right to emphasise the importance of the high monitoring costs, it has ignored the equally important costs associated with dividing the harvest. These were sufficiently large to make the contract unattractive, except in the few cases where the landowner was prepared to be actively involved in wine making and its sale, such as was found in Beaujolais or Tuscany

Why sharecropping? : explaining its presence and absence in Europe's vineyards, 1750-1950

The traditional view that sharecropping was a cause of low productivity in European agriculture prior to the Second World War has been challenged by economic historians, and today the contact is often considered as efficient at reducing the monitoring costs associated with labour and allocation of risk between landowners and farmers, especially when capital markets were weak for working capital. Yet if sharecropping was a relatively efficient contract, why was it not found more often? This paper looks at the vine, a crop that was widespread in Europe and that has been central to the current debates. It argues that while the literature has been right to emphasise the importance of the high monitoring costs, it has ignored the equally important costs associated with dividing the harvest. These were sufficiently large to make the contract unattractive, except in the few cases where the landowner was prepared to be actively involved in wine making and its sale, such as was found in Beaujolais or Tuscany.

Pratiques des jeunes et participation à la vie locale : regards croisés France - Irlande

National audienceDans la société actuelle, la recherche d’un repli domestique trouve dans les campagnes de faible densité un support de plus en plus sollicité. Le désir de se retirer y est rendu possible par la configuration de l’habitat — dispersé — et par la quantité d’espaces disponibles. J.-D. Urbain (2002) explique à propos des individus ayant une résidence secondaire dans les espaces ruraux de faible densité qu’ils recherchent la « vacance sociale ». L’isolement social s’y transforme en droit à la solitude, on n’est plus obligé d’y subir autrui. Ce contexte correspond à une tendance commune à l'ensemble des jeunes, celle du repli sur soi (Gambino, 2008). Cela laisse en effet penser que les espaces ruraux de faible densité offrent aux jeunes qui y vivent la possibilité de s’absenter du monde. Pourquoi en viennent-ils à exercer un droit de retrait qui rend invisible leur participation à la vie locale et leur attachement discret mais bien réel à leur lieu de vie ? Pour mieux comprendre ce phénomène, cet article propose une lecture des pratiques plurielles des jeunes ruraux, c'est-à-dire de « l’ensemble des comportements plus ou moins intériorisés et des activités domestiques et/ou sociales qui construisent l’identité sociale d’un individu (ou d’un groupe) » (de Certeau, 1990). Dans le cas des jeunes ruraux, elles sont encore peu connues et mal comprises, et trop souvent interprétées comme la preuve d’une désaffection pour l’espace rural

Dipturus argentinensis, argentine skate

The Argentine Skate (Dipturus argentinensis) occurs in the Southwest Atlantic from central Chubut to southern Santa Cruz, Argentina and off the northwest Falkland Islands (Malvinas). It inhabits continental and insular shelves and slopes at depths of 85–400 m. Maximum size is unknown as only immature specimens have been caught (up to 125 cm total length) and there is some question as to where the adult population occurs. This skate is captured in commercial demersal trawl fisheries, which are intense across its entire known geographic and bathymetric range. It is captured in the target trawl fishery for skates off the Falkland Islands (Malvinas). Identification is an issue, and it may be captured more than is perceived. More information is needed to determine the level of overlap with fisheries and this species' catchability and sensitivity to fishing. Research is needed on distribution, life history, population size and trends, and threats. Since it is unknown whether fishing is causing a population reduction, there is currently inadequate information available to assess the Argentine Skate beyond Data Deficient.Fil: Pollom, R.. University Fraser Simon; CanadáFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cuevas, J. M.. Wildlife Conservation Society; Estados UnidosFil: Pompert, J.. Georgia Seafoods; Países BajosFil: Herman, K.. Georgia Aquarium; Estados Unido

Comment [on "Origin of the Chichibu Sea, Japan: Middle Paleozoic to Early Mesozoic plate construction in the northern margin of the Gondwana continent" by S. Otoh, S. Yamakita, and S. Yanai]

International audienceComment [on "Origin of the Chichibu Sea, Japan: Middle Paleozoic to Early Mesozoic plate construction in the northern margin of the Gondwana continent" by S. Otoh, S. Yamakita, and S. Yanai

Explicit expressions for the minimum efficiency and most penetrating particle size of Nuclepore filters

Nuclepore filters are capillary pore membrane filters with an array of microscopic cylindrical holes of uniform diameters. Their structure is suitable for particle collection and ensuing offline analyses, therefore they are being widely used for exposure assessment of engineered nanoparticles, ambient PM2.5, virus, bacteria, asbestos, etc., as well as in powder manufacturing industries. However, there exists a particle size range in which all the filtration capture mechanisms are not effective. This size is the most penetrating particle size (MPPS), which corresponds to the minimum efficiency (ME) of the filter. Both MPPS and ME are important parameters for a user to select an adequate Nuclepore filter and preferred operating conditions. For rapid estimation of the MPPS and ME, we derived their explicit expressions by simplifying the formulas for the impaction, diffusion and interception deposition and differentiating the combined efficiency with respect to the particle size. The comparison between the experimental data and the prediction from the explicit expressions shows the explicit expressions can provide MPPS for a wide range of filter properties (pore radius, porosity and length) and filtration conditions (particle density, face velocity and temperature). The ME can also be estimated satisfactorily when a simplified term of filter surface diffusion deposition is further considered. By the explicit expressions of MPPS and ME, a quick screening for selecting a Nuclepore filter with the proper properties and suitable filtration conditions can be easily achieved. From the theoretical point of view, the explicit expressions facilitate better understanding of the effects of filter properties and conditions on the filtration characteristic