Experimental analysis of the addition of rice husk ash to the clayey subgrade of a road stabilized with lime

There are many studies about how the addition of lime and rice husk ash (RHA) gives the soil a better mechanical behavior, particularly on clayey soils, where usually fine particles reach more than 75%. However, the soils with a small presence of fine particles (59-60%) do not have much research. This analysis evaluates the influence that RHA has on this kind of soil stabilized with 3% of lime. After the initial mix of soil-lime, CBR increased 11.2 times its initial value; within the addition of the ash, the CBR averaged between 45-50% up until 28% of RHA was added, where the results decreased considerably. Soil workability improved and the specimens with more ash resulted in a more granular material, with a group index value 0 following the AASHTO standards. The greatest CBR record was obtained with the specimen of 16% RHA, 3% lime and soil, reaching a 51.3% CBR, 1.58g/cm3 of MDD and 16.5% of OMC. Yet, it only showed a 1.55% more resistance than the lime-soil specimen. The CBR with more presence of RHA tends to decrease its value, therefore for silica-rich clayey soils, the addition of lime by itself should be enough for an adequate performance

Spire stimulates nucleation by Cappuccino and binds both ends of actin filaments.

The actin nucleators Spire and Cappuccino synergize to promote actin assembly, but the mechanism of their synergy is controversial. Together these proteins promote the formation of actin meshes, which are conserved structures that regulate the establishment of oocyte polarity. Direct interaction between Spire and Cappuccino is required for oogenesis and for in vitro synergistic actin assembly. This synergy is proposed to be driven by elongation and the formation of a ternary complex at filament barbed ends, or by nucleation and interaction at filament pointed ends. To mimic the geometry of Spire and Cappuccino in vivo, we immobilized Spire on beads and added Cappuccino and actin. Barbed ends, protected by Cappuccino, grow away from the beads while pointed ends are retained, as expected for nucleation-driven synergy. We found that Spire is sufficient to bind barbed ends and retain pointed ends of actin filaments near beads and we identified Spire's barbed-end binding domain. Loss of barbed-end binding increases nucleation by Spire and synergy with Cappuccino in bulk pyrene assays and on beads. Importantly, genetic rescue by the loss-of-function mutant indicates that barbed-end binding is not necessary for oogenesis. Thus, increased nucleation is a critical element of synergy both in vitro and in vivo

Modelo Interno para el cálculo del capital de solvencia obligatorio para el riesgo de mortalidad en Solvencia II

Solvencia II ofrece a las compañías de seguros la posibilidad de utilizar distintos métodos para calcular el capital de solvencia obligatorio; éstos se basan en los denominados modelo estándar y modelo interno. En este trabajo se propone un modelo interno para el cálculo del capital de solvencia obligatorio que cuantifica el riesgo de mortalidad, para una cartera formada por seguros de vida, en el que la compañía de seguros garantiza un único pago al beneficiario en caso de fallecimiento del asegurado. Se asume la interpretación del capital de solvencia obligatorio como el valor en riesgo, al 99,5%, de la diferencia entre el valor actualizado de los activos menos los pasivos de dos años consecutivos. La metodología propuesta para su cálculo se basa en simular por el método de Monte Carlo la evolución de siniestralidad de la cartera. Por último se compara, para una misma cartera, el capital de solvencia obligatorio obtenido por modelo interno propuesto con el que resulta de utilizar el modelo estándar

Reaseguro Finite Risk en ambiente financiero estocástico

Una de las características del reaseguro finite risk es la existencia de una cuenta de experiencia, que está formada por las primas que cobra el reasegurador, junto con su rendimiento financiero,y su finalidad es financiar los siniestros que éste ha de satisfacer a la cedente en el plazo establecido. El objetivo de este trabajo es diseñar un modelo que permita determinar el saldo estimado o reserva que debe de tener en cada periodo anual la cuenta de experiencia para garantizar su solvencia dinámica, teniendo en cuenta la experiencia de siniestralidad de la cartera del reasegurador y de cada cedente. Para el cálculo de la prima de reaseguro y del saldo de la cuenta de experiencia se asumirá ambiente financiero estocástico, de modo que la prima de reaseguro dependerá también de otros parámetros como la volatilidad del tipo de interés o de la aversión al riesgo

Amb quin esport escolar somien les famílies?

En aquest article es recullen les opinions de les famílies de tres centres escolars (Azkue ikastola de Lekeitio, Betiko ikastola de Leioa i Seber Altube ikastola de Gernika), pertanyents a la Federació d’Ikastoles de Bizkaia (FIB/BIE). Les opinions recollides es troben relacionades amb una forma pròpia d’entendre l’esport escolar, que es veurà materialitzada en l’expressió dels seus somnis. Aquestes opinions han estat recollides pels coordinadors dels centres, a través dels debats que es desenvolupaven en els grups de discussió, convocats amb aquest objectiu, amb diferents audiències (escolars, famílies, monitors, professors i direccions dels centres). El procés d’investigació seguit en el seminari se centra en processos d’interpel·lació, interrogació, contrastació i redefinició, per la qual cosa s’ajusta a un estudi qualitatiu que se centra en la construcció conjunta del coneixement (Pérez Gómez, 1994, Imbernon, 1994)

Deconvolution of pro- and antiviral genomic responses in Zika virus-infected and bystander macrophages.

Genome-wide investigations of host-pathogen interactions are often limited by analyses of mixed populations of infected and uninfected cells, which lower sensitivity and accuracy. To overcome these obstacles and identify key mechanisms by which Zika virus (ZIKV) manipulates host responses, we developed a system that enables simultaneous characterization of genome-wide transcriptional and epigenetic changes in ZIKV-infected and neighboring uninfected primary human macrophages. We demonstrate that transcriptional responses in ZIKV-infected macrophages differed radically from those in uninfected neighbors and that studying the cell population as a whole produces misleading results. Notably, the uninfected population of macrophages exhibits the most rapid and extensive changes in gene expression, related to type I IFN signaling. In contrast, infected macrophages exhibit a delayed and attenuated transcriptional response distinguished by preferential expression of IFNB1 at late time points. Biochemical and genomic studies of infected macrophages indicate that ZIKV infection causes both a targeted defect in the type I IFN response due to degradation of STAT2 and reduces RNA polymerase II protein levels and DNA occupancy, particularly at genes required for macrophage identity. Simultaneous evaluation of transcriptomic and epigenetic features of infected and uninfected macrophages thereby reveals the coincident evolution of dominant proviral or antiviral mechanisms, respectively, that determine the outcome of ZIKV exposure

Effects of experimental lightgaps and topography on enrichment plantings in a central Amazonian secondary forest

Enrichment plantings into secondary forest are an important option in restoring species diversity and ecosystem services. However, little attention has been given to environmental requirements for species performance. This study evaluated the effects of lightgaps and topographic position on the growth and survival of four native tree species (Pouteria caimito, Garcinia macrophylla, Dipteryx odorata and Cynometra bauhiniaefolia) planted into a 26-year old secondary forest originating from abandoned pastures in the central Amazon Basin. Artificial lightgaps and control plots under closed canopy were uniformly distributed on plateaus and bottomlands near water bodies. Seedlings were planted randomly into the plots and monitored for 28 months. Seedling survival rate was high (93%) and did not differ among species. Overall, lightgaps produced a 38% increase in seedling height relative to the controls. Although the four species naturally occur in mature forest, two of the four grew significantly more in lightgaps than in dosed canopy secondary forest. Overall, bottomlands facilitated greater seedling growth in height (38%) relative to plateaus, but only one species exhibited a significant increase. This study shows the importance of the environmental variability generated with canopy openings along the topographic gradient, suggesting that both the selection of species and microsite conditions of planting sites have to be considered important criteria in the recovery of degraded areas