On the construction of a finite Siegel space

In this note we construct a finite analogue of classical Siegel's Space. Our approach is to look at it as a non commutative Poincare's half plane. The finite Siegel Space is described as the space of Lagrangians of a $2n$ dimensional space over a quadratic extension $E$ of a finite base field $F$. The orbits of the action of the symplectic group $Sp(n,F)$ on Lagrangians are described as homogeneous spaces. Also, Siegel's Space is described as the set of anti-involutions of the symplectic group.2

Rapid kinetics of the interaction between daunomycin and drug-sensitive or drug-resistant P388 leukemia cells

AbstractThe initial stages of the interaction of daunomycin (DNM) with drug-sensitive (P388/S) and drug-resistant (P388/100) cells have been defined by a rapid kinetics stopped-flow procedure. The process can be described by two kinetic components. The faster component accounts for rapid occupation of cell surface sites by DNM, as supported by experiments with liposomes with different surface charge. On the other hand, the effect of verapamil in the assays, suggests that the slower component is involved in the transport of the drug into the cells. Our observations are consistent with a loss in the control of the passive permeability to the drugs in the drug-resistant tumor cells

Stationary and pulsating dissipative light bullets from a collective variable approach

A collective variable approach is used to map domains of existence for (3+1)-dimensional spatiotemporal soliton solutions of a complex cubic-quintic Ginzburg-Landau equation. A rich variety of evolution behaviors, which include stationary and pulsating dissipative soliton dynamics, is revealed. Comparisons between the results obtained by the semianalytical approach of collective variables, and those obtained by a purely numerical approach show good agreement for a wide range of equation parameters. This also demonstrates the relevance of the semianalytical method for a systematic search of stability domains for spatiotemporal solitons, leading to a dramatic reduction of the computation time

Aristonectes quiriquinensis, sp. nov., a new highly derived elasmosaurid from the upper Maastrichtian of central Chile

This paper describes a new species of elasmosaurid plesiosaur, Aristonectes quiriquinensis, sp. nov., based on a partial skeleton recovered from upper Maastrichtian beds of the Quiriquina Formation of central Chile. The material described here consists of two skeletons, one collected near the village of Cocholgue, and a second juvenile specimen from Quiriquina Island. Prior to these finds, Aristonectes was viewed as a monospecific genus, including only the enigmatic Aristonectes parvidens, the holotype of which consists of an incomplete skull and incomplete postcranium. Other material referred to the genus includes an incomplete juvenile skull and other postcranial material from the upper Maastrichtian of Antarctica, as well as a partial skull from the Quiriquina Formation of central Chile. The relationships of Aristonectes have been controversial, with competing theories assigning the genus to Cryptoclididae, Elasmosauridae, and Aristonectidae; however, there is a developing consensus that Aristonectes is a derived elasmosaurid, and this paper gives strong evidence for this view. Comparison of the specimen here studied with the holotype of A. parvidens demonstrates that A. quiriquinensis is a distinct species. The completeness of the adult skeleton allows the first confident size estimates for adult Aristonectes. It is a large plesiosaurian with a relatively large skull with numerous homodont teeth, a moderately long and laterally compressed neck, and relatively narrow trunk, with slender and elongate forelimbs. The two specimens are restricted to the upper Maastrichtian of central Chile, posing questions concerning the austral circumpolar distribution of different elasmosaurids towards the end of the Cretaceous.Fil: Otero, Rodrigo A.. Universidad de Chile; ChileFil: Soto Acuña, Sergio. Museo Nacional de Historia Natural de Santiago; Chile. Universidad de Chile; ChileFil: O'Keefe, Frank Robin. Marshall University; Estados UnidosFil: O'gorman, Jose Patricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; ArgentinaFil: Stinnesbeck, Wolfgang. Heidelberg University; AlemaniaFil: Suárez, Mario E.. Museo Nacional de Historia Natural de Santiago; Chile. Universidad de Chile; ChileFil: Rubilar-Rogers, David. Museo Nacional de Historia Natural de Santiago; Chile. Universidad de Chile; ChileFil: Salazar, Christian. Museo Nacional de Historia Natural de Santiago; Chile. Universidad de Chile; ChileFil: Quinzio Sinn, Luis Arturo. Universidad de Concepción; Chil

Fragility Curves for Thin-Walled Cold-Formed Steel Wall Frames Affected by Ground Settlements Due to Land Subsidence

Land subsidence phenomenon due to ground water withdrawal is a current problem in many places around the world, particularly in the shallows of Mexico. This causes ground differential settlements that affect structures, mainly dwellings and buildings based on reinforced concrete and masonry. Eventually, these structural materials do not exhibit an adequate performance beyond a certain level of angular distortion. This work presents the results about a study regarding the performance of thin-walled cold-formed steel wall frames with different sheathing systems affected by angular distortions simulating ground differential settlements due to land subsidence. The wall frames are composed by vertical (studs) and horizontal elements (tracks), with different sheathing systems: polystyrene, OSB, gypsum and calcium silicate. By means of experimental testing of wall frames subjected to monotonic lateral loads, the rotational stiffness was obtained for the wall frames with polystyrene. Likewise the rotational stiffness of the other wall frame systems was calculated based on the data provided by other author’s publications. On the other hand, by means of numerical simulation, all the wall frame systems were modeled in structural analysis software, calibrating them based on the rotational stiffness. Also, the moment-rotation curves were calculated for the studs and tracks based on the direct strength method. A non-linear static pull down analysis was performed producing several degrees of angular distortion simulating ground settlements for all the wall frames sheathing systems. With the data acquired fragility curves were calculated according three levels of damage for the wall frames with different sheathing system

The 2016 seismic series in the south Alboran Sea: Seismotectonics, Coulomb Failure Stress changes and implications for the active tectonics in the area

The Southern Alboran Sea, particularly the area offshore Al Hoceima Bay, presents moderate but continuous seismic activity since the Mw 6.0 1994 Al Hoceima earthquake. The maximum magnitude occurred in the area was a Mw 6.3 earthquake in the 2004 Al Hoceima – Tamasint seismic series. Since then, the seismicity in the Al Hoceima area has been usual, with maximum seismic magnitudes around 4. An increase in the seismic rate was registered during 2015, especially from May, culminating in the seismic series in January 2016. The mainshock occurred on January 25th 2016 with a magnitude Mw 6.3 and it was preceded by a Mw 5.1 foreshock on January 21st. The seismic series took place at the western end of the Alboran Ridge. Towards the northeast the Alboran Ridge bends, and seems to be connected with the NW-SE right-lateral transtensional Yusuf Fault. The recorded seismicity is mainly located in the Alboran Ridge area and along the N-S Al-Idrisi Fault that seems to continue southwards, towards the Al Hoceima Bay. The focal mechanisms calculated previously in the area showed a leftlateral strike-slip faulting with some normal component in the Alboran Ridge; but always within a complex system of diffuse deformation and high rupture type variability. We have used 41 computed focal mechanisms of this seismic series to analyze its seismotectonics and structural characteristics. To group the focal mechanisms we used a clustering algorithm using the spatial distribution of the events and also the type of rupture mechanism. For each cluster we have obtained the composed focal mechanism, associating it to a particular fault or family of structures. We have tested the mechanical compatibility of these structures by Coulomb Failure Stress transfer modeling. The mainshock of the series occurred in the Al Idrisi Fault intersecting the western Alboran Ridge. This event triggered aftershocks and independent series in left-lateral strike-slip faults associated with the Al Idrisi Fault System towards the south, but also in near pure reverse faults in the fault zone bounding the the Alboran Ridge. Both types of faults and rupture-mechanisms coexist, linked mechanically by stress transfer, being coeval the uplift of the Alboran Ridge and its northwestward displacement due to the left-lateral motion of the Al-Idrisi Fault. It is also discussed how the contrasting faulting processes and seismic ruptures are developed in two differentially oriented fault zones in the context the current NW-SE plate convergence between the African and Eurasian plates in the Westernmost Mediterranean

La producciòn académica como uno de los indicadores del desempeño de las universidades públicas colombianas desde la perspectiva del análisis envolvente de datos

Este articulo compara los resultados obtenidos por un modelo propuesto por la Subcomisión Técnica del Sistema de Universidades Estatales basado en la técnica multivariada “Análisis de Componentes Principales”, combinada con Regresión Lineal, y que fue usado para medir el desempeño en investigación y formación en las universidades publicas Colombianas versus la perspectiva resultante de aplicar a éste mismo problema la técnica del Análisis Envolvente de Datos-DEA. La compresión obtenida mediante la comparación de los dos modelos nos lleva a considerar como mas adecuado el enfoque DEA para valorar las eficiencias de la universidades con respecto al factor de producción

La producciòn académica como uno de los indicadores del desempeño de las universidades públicas colombianas desde la perspectiva del análisis envolvente de datos

Este articulo compara los resultados obtenidos por un modelo propuesto por la Subcomisión Técnica del Sistema de Universidades Estatales basado en la técnica multivariada “Análisis de Componentes Principales”, combinada con Regresión Lineal, y que fue usado para medir el desempeño en investigación y formación en las universidades publicas Colombianas versus la perspectiva resultante de aplicar a éste mismo problema la técnica del Análisis Envolvente de Datos-DEA. La compresión obtenida mediante la comparación de los dos modelos nos lleva a considerar como mas adecuado el enfoque DEA para valorar las eficiencias de la universidades con respecto al factor de producción

La producciòn académica como uno de los indicadores del desempeño de las universidades públicas colombianas desde la perspectiva del análisis envolvente de datos

Este articulo compara los resultados obtenidos por un modelo propuesto por la Subcomisión Técnica del Sistema de Universidades Estatales basado en la técnica multivariada “Análisis de Componentes Principales”, combinada con Regresión Lineal, y que fue usado para medir el desempeño en investigación y formación en las universidades publicas Colombianas versus la perspectiva resultante de aplicar a éste mismo problema la técnica del Análisis Envolvente de Datos-DEA. La compresión obtenida mediante la comparación de los dos modelos nos lleva a considerar como mas adecuado el enfoque DEA para valorar las eficiencias de la universidades con respecto al factor de producción