Workers of the world and workers of a single industry : communist strike policy on the waterfront, Le Havre 1920-1970

International audienceCommunists, always a minority in the face of a libertarian, apolitical or broad left majority in the dockers union, through the study of five strike conjunctures with different international and national configurations

Fluid evolution in an Oceanic Core Complex: a fluid inclusion study from IODP hole U1309 D - Atlantis Massif, 30°N, Mid-Atlantic Ridge

In the detachment mode of slow seafloor spreading, convex-upward detachment faults take up a high proportion of the plate separation velocity exposing gabbro and serpentinized peridotite on the seafloor. Large, long-lived hydrothermal systems such as TAG are situated off axis and may be controlled by fluid flow up a detachment fault, with the source of magmatic heat being as deep as 7 kmbsf. The consequences of such deep circulation for the evolution of fluid temperature and salinity have not previously been investigated. Microthermometry on fluid inclusions trapped in diabase, gabbro, and trondjhemite, recovered at the Atlantis Massif Oceanic Core Complex (30°N, Mid-Atlantic Ridge), reveals evidence for magmatic exsolution, phase separation, and mixing between hydrothermal fluids and previously phase-separated fluids. Four types of fluid inclusions were identified, ranging in salinity from 1.4 to 35 wt % NaCl, although the most common inclusions have salinities close to seawater (3.4 wt % NaCl). Homogenization temperatures range from 160 to >400°C, with the highest temperatures in hypersaline inclusions trapped in trondjhemite and the lowest temperatures in low-salinity inclusions trapped in quartz veins. The fluid history of the Atlantis Massif is interpreted in the context of published thermochronometric data from the Massif, and a comparison with the inferred circulation pattern beneath the TAG hydrothermal field, to better constrain the pressure temperature conditions of trapping and when in the history of exhumation of the rocks sampled by IODP Hole U1309D fluids have been trapped

Producción de sedimentos y nutrientes en dos cuencas agrícolo-ganaderas del centro de la Provincia de Buenos Aires (Argentina)

Se utilizaron 22 muestras obtenidas entre febrero de 2013 y marzo de 2014 para evaluar la producción de sedimentos y nutrientes en dos cuencas agrícolo-ganaderas del centro de la provincia de Buenos Aires. Se midió la Concentración de Sólidos Suspendidos (CSS) por gravimetría; la fracción gruesa por sedimentación en 48-72hs, y la fracción fina por filtración del sobrenadante por fibra de vidrio (capacidad de retención: 0,5μm). Las muestras del arroyo Videla (135km2) fueron tomadas con caudales entre 0,27 y 1,10m3/s. La CSS media fue de 28g/m3, y el caudal sólido medio fue de 1280kg/día, siendo el 95% material grueso. La producción media de fósforo y nitrógeno fue de 4,43 y 239kg/día respectivamente, el 88% en forma de nitrato. Las muestras del arroyo Santa Catalina (121km2) fueron tomadas con caudales entre 0,09 y 0,61m3/s. La CSS media fue de 93g/m3, y el caudal sólido medio fue de 2118kg/día, siendo el 90% material grueso. La producción media de fósforo y nitrógeno fueron de 7,09 y 78kg/día respectivamente, el 69% en forma de nitrato. Se observaron diferencias significativas en la CSS, y la concentración de fósforo y nitrógeno entre ambas cuencas (α>0,95; test de Wilcoxon).Twenty two samples collected between February 2013 and March 2014 were used to evaluate the production of sediments and nutrients of two basins located in the center of Buenos Aires province. Total Suspended Solids (TSS) was measured by gravimetry; the coarse fraction by sedimentation on 48-72 hours, and the fine fraction by filtering the supernatant through glass fiber filter (0,5μm retention capacity). Samples from Videla stream (135km2) were collected during 0,27 to 1,10m3/s water flowrate. Average TSS was 28g/m3, and the average solid load was 1280kg/day, 95% coarser material. Average production of phosphorus and nitrogen were 4,43 and 239kg/day respectively, 88% as nitrate. Samples from Santa Catalina stream (121km2) were collected during 0,09 to 0,61m3/s water flowrate. Average TSS was 93g/m3, and the average solid load was 2118kg/day, 90% as coarser material. Average production of phosphorus and nitrogen were 7,09 and 78kg/day respectively, 69% as nitrate. Significant differences in TSS, nitrogen and phosphorus concentration were observed between these two basins (α>0,95; Wilcoxon test)

Quien contamina, paga: ¿avance legislativo?

Aside from higly developed countries, it was not until few years back that some efforts were devoted to meet the goals of economical growth and natural resources quality preservation. Because of that, their rules or laws do not address what today emerges as demands by the society: a rather high living standard and the enjoyment of a non-polluted environment. Such rules deem proper to apply economical fines to those who pollute the environment. Thus, a situation is set up so that contamination is virtually allowed as long as the national treasure gets its share. That is known as the “pollutant-payer” principle (PPP). This paper seeks the juridical validity of such principle, and finds it unfear, ethically questionable, and weak as a law-making thought. It is seen, at the most, as a complement of an action aimed at the restoration of the damaged system to its original status. Given such a lack of juridical support, the second part of this paper explores the limiting factors and characteristics of water resources (surface and groundwater) which may have incidence in looking for an updated set of rules or laws to address the above mentioned demands of the societies in the verge of the XX century.Salvo en países de avanzada, hasta no hace muchos años pocos esfuerzos se volcaban a la compatibilización del crecimiento económico con la conservación de la calidad de los recursos naturales. Por la misma razón, las legislaciones o normas no reflejan adecuadamente lo que hoy se presentan como demandas de la sociedad: el alcance de un buen pasar económico y el disfrute de un medio ambiente no contaminado. Las legislaciones aludidas, cuando lo hacen, juzgan que es procedente aplicar sanciones económicas a aquellos que degradan el medio. Se establece, de hecho, una situación que permite contaminar en tanto se aporte al estado. Se lo conoce como el principio del contaminador-pagador (PCP). Este trabajo analiza la validez jurídica de ese precepto, y lo encuentra inequitativo, falto de ética, y por ende endeble en cuanto a derecho. Se lo concibe, en todo caso, como un complemento a la restitución de lo dañado o alterado a su situación original. Aceptando dicha falta de sustento jurídico, la segunda parte del trabajo explora los condicionantes y características de las aguas superficiales y subterráneas que podrían incidir llegado el momento de buscar una salida jurídica más acorde con los tiempos y las arriba aludidas demandas de las sociedades de fin del siglo XX

Bacteriología de aguas subterráneas: metodología para el diseño de muestreo en áreas urbanas

El propósito de esta comunicación es presentar un método objetivo para la planificación del muestreo bacteriológico del agua subterránea en sectores urbanos, relacionando la intensidad de muestreo con una estimación expeditiva del riesgo sanitario por consumo humano de agua de baja calidad