Cycle classes and the syntomic regulator

Let $V=Spec(R)$ and $R$ be a complete discrete valuation ring of mixed characteristic $(0,p)$. For any flat $R$-scheme $X$ we prove the compatibility of the de Rham fundamental class of the generic fiber and the rigid fundamental class of the special fiber. We use this result to construct a syntomic regulator map $r:CH^i(X/V,2i-n)\to H^n_{syn}(X,i)$, when $X$ is smooth over $V$, with values on the syntomic cohomology defined by A. Besser. Motivated by the previous result we also prove some of the Bloch-Ogus axioms for the syntomic cohomology theory, but viewed as an absolute cohomology theory.Comment: 23 pages, improved expositio

Postharvest 1-methylcyclopropene application in ripening control of ‘Stark Red Gold’ nectarines: Temperature-dependent effects on ethylene production and biosynthetic gene expression, fruit quality, and polyamine levels

Stark Red Gold nectarines were harvested at 30 N of flesh firmness (FF) and 1 nl g-1 h-1 of ethylene production, and treated in sealed plastic containers with 1 µl l-1 (1 ppm) 1-methylcyclopropene (1-MCP) for 12 h at 25°C. Treated and control fruit were then transferred either to a growth chamber at 25°C or to a cold room at 4°C for 3 days. At the end of treatment with 1-MCP, ethylene production in control fruit had increased relative to production at harvest; and this rise was abolished by the presence of the chemical. Moreover, treated fruit showed lower soluble solids content (SSC) and higher FF and titratable acidity (TA) as compared to control ones, and putrescine and spermine levels were moderately enhanced in the mesocarp at the end of treatment. In contrast with the inhibition of ethylene production, 1-aminocyclopropane-1-carboxylate synthase (ACS) and especially 1-aminocyclopropane-1-carboxylate oxidase (ACO1 and ACO2) transcript levels were enhanced relative to controls. During storage, 1-MCP affected ethylene production and biosynthetic gene expression, fruit softening and other quality parameters in a temperature-dependent manner: in fruit held at 25°C a strong decrease in ethylene production, a delay in ripening and lower ACS and ACO1/ACO2 levels were recorded; while in fruit held at 4°C an opposite trend was observed. Resuts suggest that 1-MCP application followed by storage at 25°C appears effective in controlling postharvest ripening. The lack of efficacy of the chemical in cold-stored fruit is discussed in relation to changes in SAMDC gene expression and putrescine accumulation in treated fruit relative to controls, which may be part of a stress response

La redefinición del espacio público: el caso de las escuelas autogestionadas en Argentina Redefining the public sphere: self-managed schools in Argentina

El Proyecto de las Escuelas Experimentales o Autogestionadas de la Provincia de San Luis adquiere sentido en el marco de la denominada Transformación Educativa y de las políticas desarrolladas en las últimas décadas en Argentina, que, al igual que en gran parte de los países latinoamericanos, han estado orientadas por discursos y prácticas tendientes a legitimar un nuevo modelo económico, social, político, cultural y educativo. La reforma educativa argentina de la década del '90 puede analizarse como una respuesta frente a la crisis de la matriz estado-céntrica que caracterizó la institucionalización y expansión del sistema educativo. El Proyecto de las Escuelas Experimentales en la Provincia de San Luis, inspirado en el modelo de las charter schools de Estados Unidos, es presentado por el Gobierno de la Provincia como un caso precursor en nivel regional en el marco de lo que caracterizan como la "necesaria e imperante reforma de los sistemas educativos". En este sentido, el objetivo de este trabajo es analizar la lógica que orienta el modelo de estas escuelas así como presentar algunas problemáticas centrales vinculadas con el proceso de implementación de la propuesta.<br>The educational reform that took place in Argentina during the '90s was an answer to the crisis of the state-centered model that fostered the expansion of the school system in the XXth. Century. This reform assumed that the solution to improve the quality of education should focus on such issues as: reducing the role of the state in the system assessment; profoundly reforming the school organization; considering new forms of demand-side financing; introducing incentives; giving autonomy to individual schools; involving non-state institutions in policy management; producing information in order to guarantee the freedom of choice; offering new career for teachers based on merit and derogation of the labor statute. Nevertheless, the educational reform should be analyzed in the context of a broader reform process implemented in the whole Latin America in the '90s, aimed at legitimating a new economic, social, political and cultural model. Inspired in the "charter schools" model, the Experimental Schools Project in the Province of San Luis is a leading case in the region of what is characterized as the "necessary and imperative reform of the educational systems". In this context, the aim of this article is both to analyze the logic behind this model and to discuss the main issues of its implementation process