Clay mineralogy of South Atlantic surface sediments

Surface samples, mostly from abyssal sediments of the South Atlantic, from parts of the equatorial Atlantic, and of the Antarctic Ocean, were investigated for clay content and clay mineral composition. Maps of relative clay mineral content were compiled, which improve previous maps by showing more details, especially at high latitudes. Large-scale relations regarding the origin and transport paths of detrital clay are revealed. High smectite concentrations are observed in abyssal regions, primarily derived from southernmost South America and from minor sources in Southwest Africa. Near submarine volcanoes of the Antarctic Ocean (South Sandwich, Bouvet Island) smectite contents exhibit distinct maxima, which is ascribed to the weathering of altered basalts and volcanic glasses. The illite distribution can be subdivided into five major zones including two maxima revealing both South African and Antarctic sources. A particularly high amount of Mg- and Fe-rich illites are observed close to East Antarctica. They are derived from biotite-bearing crystalline rocks and transported to the west by the East Antarctic Coastal Current. Chiorite and well-crystallized dioctaedral illite are typical minerals enriched within the Subantarctic and Polarfrontal-Zone but of minor importance off East Antarctica. Kaolinite dominates the clay mineral assemblage at low latitudes, where the continental source rocks (West Africa, Brazil) are mainly affected by intensive chemical weathering. Surprisingly, a slight increase of kaolinite is observed in the Enderby Basin and near the Filchner-Ronne Ice shelf. The investigated area can be subdivided into ten, large-scale clay facies zones with characteristic possible source regions and transport paths. Clay mineral assemblages of the largest part of the South Atlantic, especially of the western basins are dominated by chlorite and illite derived from the Antarctic Peninsula and southernmost South America and supported by advection within the Circumantarctic Deep Water flow. In contrast, the East Antarctic provinces are relatively small. Assemblages of the eastern basins north of 30°S are strongly influenced by African sources, controlled by weathering regimes on land and by a complex interaction of wind, river and deep ocean transport. The strong gradient in clay mineral composition at the Brazilian slope indicate a relatively low contribution of tropically derived assemblages to the western basins.

Los más pequeños toman la palabra: La Escuela Infantil que a ellos les gustaría

El derecho a ser escuchado y participar en aquellos asuntos que afectan a los niños es un derecho fundamental de la infancia escasamente respetado por el adulto, quien tiende a silenciar su voz, infravalorando su visión y posible aportación. Ante esta realidad, la Escuela Infantil se erige como un marco privilegiado para la escucha y la participación de la infancia en aquellos temas que les afectan, contribuyendo a la formación de ciudadanos democráticos. A partir de un marco de escucha donde se concibe al pequeño como un sujeto activo, competente y experto en su propia vida, se ha llevado a cabo una investigación que ha adoptado el formato de estudio de caso, en la que se ha recogido a través de las técnicas del dibujo y de las conversaciones con niños, la visión que poseen los más pequeños sobre la Escuela Infantil, analizando el bienestar del niño en el contexto escolar, el sentido y finalidad que los niños otorgan a la escuela; el grado de satisfacción con la misma; sus gustos y preferencias en el contexto escolar; la autonomía y libertad que dicen poseer en la escuela; su visión sobre los aspectos organizativos que rigen el funcionamiento del centro y su perspectiva sobre cómo es y cómo les gustaría que fuera la participación de las familias en la escuela. Finalmente, se recogen sus propuestas de mejora para hacer de la Escuela Infantil a la que asisten su escuela ideal. Los resultados del estudio ponen de manifiesto la demanda de los niños de una Escuela Infantil diferente a la que conocen y la existencia de un pensamiento divergente del pensamiento adulto que es necesario escuchar y tener en consideración, siendo sus aportaciones de gran valía para poder iniciar procesos de innovación y mejora educativa.

Contraprestaciones por los servicios financieros del Consulado de México y sus miembros: los fondos extraordinarios para la guerra contra Gran Bretaña, 1779-1783

Nueva España aportó la mayor parte de los recursos que sostuvieron a las fuerzas armadas españolas durante la guerra contra Gran Bretaña que se desarrolló en el Caribe entre 1779 y 1783. En el artículo se analizan las medidas a las que recurrieron las autoridades reales para obtener recursos extraordinarios del Consulado y varios mercaderes de la ciudad de México. Asimismo se exponen algunas de las contraprestaciones que negociaron a cambio de dichos servicios financieros y se plantean diversas hipótesis acerca de los motivos económicos, sociales y políticos que los llevaron a colaborar con el monarca, teniendo en cuenta los negocios que realizaban durante el conflicto bélico y la forma en que eran afectados por la reciente apertura comercial.

Who are you?

[EN]Most automatic recognition systems are focused on recognizing, given a single mug-shot of an individual, any new image of that individual. Most verification systems are designed to authenticate an identity provided by the user. However, the previous work rarely focus on the problem of detecting when a new individual, i.e., an unknown one, is present. The goal of the work presented in this paper deals with the possibility of providing the system with basic tools to detect when a new individual starts an interactive session, in order to allow the system to add or improve an identity model in the database. Experiments carried out with a set of 36 different individuals show promising results.

Graja - Autobewerter für Java-Programme

In diesem Bericht wird der Autobewerter Graja für Java-Programme vorgestellt. Wir geben einen Überblick über die unterstützten Bewertungsmethoden sowie die beteiligten Nutzerrollen. Wir gehen auf technische Einzelheiten und Randbedingungen der in Graja eingesetzten Bewertungsmethoden ein und zeigen die Einbindung von Graja in eine technische Gesamtarchitektur. An einem durchgehenden Beispiel stellen wir die Struktur einer Programmieraufgabe sowie die von Graja unterstützten Feedback-Möglichkeiten dar. Informationen zum bisherigen Einsatz des Graders runden den Bericht ab.

Gateway National Recreation Area, New York-New Jersey /

"*GPO: 1988--201-941/8002[5?]. Reprint 1988."

The Becker-Döring equations with monomer input, competition and inhibition

We investigate the Becker-Döring model of nucleation with three generalisations; an input of monomer, an input of inhibitor and finally, we allow the monomers to form two morphologies of cluster. We assume size-independent aggregation and fragmentation rates. Initially we consider the problem of constant monomer input and determine the steady-state solution approached in the large-time limit, and the manner in which it is approached. Secondly, in addition to a constant input of monomer we allow a constant input of inhibitor, which prevents clusters growing any larger and this removes them from the kinetics of the process; the inhibitor is consumed in the action of poisoning a cluster. We determine a critical ratio of poison to monomer input below which the cluster concentrations tend to a non-zero steady-state solution and the poison concentration tends to a finite value. Above the critical input ratio, the concentrations of all cluster sizes tend to zero and the poison concentration grows without limit. In both cases the solution in the large-time limit is determined. Finally we consider a model where monomers form two morphologies, but the inhibitor only acts on one morphology. Four cases are identified, depending on the relative poison to monomer input rates and the relative thermodynamic stability. In each case we determine the final cluster distribution and poison concentration. We find that poisoning the less stable cluster type can have a significant impact on the structure of the more stable cluster distribution; a counter-intuitive result. All results are shown to agree with numerical simulation.

Improvement of the oral praziquantel anthelmintic effect by cyclodextrin complexation

Schistosomiasis is a parasitic disease which kills a half million people per year, a I I over the world. Praziquantel (PZQ) is the drug-of-choice for schistosomiasis because of its effectiveness, ease of administration, and low cost. However, poor solubility restricts its delivery, especially via the oral route. In this study, we describe beta-cyclodextrin (beta-CD) complexation as an alternative to improve the PZQ bioavailability. Physicochemical analysis were performed to characterize the inclusion complex formed between PZQ and beta-CD. Differential scanning calorimetry (DSC) thermograms and morphological analysis using scanning electronic microscopy (SEM) gave evidences of the complex formation. Diffusion NMR experiments allowed determination of the fraction of PZQ bound to beta-CD (37%) and the association constant (941 +/- 47 M(-1)). The in vivo evaluation of the complexation on the effect of PZQ was performed on mice infected with Schistosoma mansoni (BH strain); after 15 days of treatment with the PZQ:beta-CD complex the efficacy, evaluated by the number of remaining alive worms, was 99%, against 59% elicited by plain PZQ.