Resumen Una vez finalizada la conquista, la paz no resultó estable ni su horizonte homogéneo. Y el período colonial da cuenta fundamentalmente de esa inestabilidad y, en él, particularmente la obra de Carlos de Sigüenza y Góngora (1645-1700). La inquietud en dicha obra por la violencia original, por su representación y, sobre todo, por su remanencia han sido leídas muchas veces como una preocupación criolla por la continuidad (o ruptura) entre pasado y presente o por la elaboración de una historia capaz de proyectar o sostener algún futuro cierto. No obstante, y como suele suceder con la literatura de Sigüenza y Góngora, otra parece ser la pregunta que desvela una y otra vez su multiforme escritura, desplazando el problema de la continuidad (o ruptura) y organizando, paralelamente, su archivo: ¿cómo reunir lo que ya se encuentra junto?, ¿cómo contar la contigüidad de presente y pasado? El siguiente ensayo pretende rastrear, siguiendo las distintas obras de Sigüenza y Góngora, la forma que su escritura adopta para dar lugar a dichas cuestiones.

Abstract Once finalized the conquest, peace was not constant, nor was not stable nor its horizon homogeneous. The colonial period expounds this instability and the works of Carlos de Sigüenza y Góngora (1645-1700) show it especially. The inquisitiveness of Sigüenza’s works about the original violence and its representation and persistence has been interpreted as a creole preoccupation with the continuity (or rupture) between past and present or as the elaboration of a history capable of projecting or sustaining some certain future. However, as it is usual in Sigüenza y Góngora’s literature, another question appears in his singular writing and shifts the continuity (or rupture) problem, organizing his archive: how to gather what is already together? How to express the adjacency of past and present? The following essay aims to trace, in the different works of Sigüenza y Góngora, how these issues take form in his writing.

Resumo A obra e a figura de Carlos de Sigüenza y Góngora (1645-1700) apresentam repetidamente um duplo problema de inscrição na literatura latino-americana: em termos críticos, ambas são percebidas e concebidas no vasto e diversificado campo histórico definido pelas crónicas de Indias, já no espaço ainda difuso, mas revolucionário, de uma ciência da suposta modernidade; em termos históricos, a obra e a figura de Sigüenza y Góngora foram colocadas, curiosamente, mas não por acaso, em séries que as afastam do século XVII e de seu barroco, tão urbano quanto letrado. O presente artigo propõe estudar aquela inscrição e indicar como ela adquire importância fundamental na edição de seus textos, na concepção e prática de sua literatura e na capacidade de tudo isso para articular, na América, redes agentes, eventos e ideias distintos e renovados que surgem hoje sob o signo do arquivo.

Abstract The work and figure of Carlos de Sigüenza y Góngora (1645-1700) recurrently appear doubly inscribed in Latin American literature: firstly, in critical terms, work and figure are perceived and conceived within the vast and diverse historical field that defined the crónicas de Indias, and in the still vague but revolutionary space of a presumably modern science; secondly, in historical terms, work and figure are also curiously but not casually placed in different series that distance them from the 17th century and its Baroque, which was both urban and literate. Besides studying this last inscription, this article also seeks to point out how this inscription gains fundamental importance in the edition of his texts, in the conception and practice of his literature and in the capacity these elements generate to articulate, in Latin America, diverse and renewed networks of agents, events and ideas that today appear under the guise of the archive.

Resumen La obra y la figura de Carlos de Sigüenza y Góngora (1645-1700) presentan recurrentemente un problema doble de inscripción en la literatura de América: en términos críticos, obra y figura son percibidas y concebidas, ya en el vasto y diverso campo histórico que definieran las crónicas de Indias, ya en el todavía difuso pero revolucionario espacio de una ciencia de presunta modernidad; en términos históricos, son puestas, curiosa pero no casualmente, en series que las alejan del siglo XVII y su barroco, tan urbano como letrado. El presente artículo se propone, además de estudiar dicha inscripción, señalar cómo es ella la que adquiere fundamental importancia en la edición de sus textos, en la concepción y práctica de su literatura y en la capacidad de todo ello para articular, en América, redes diversas y renovadas de agentes, acontecimientos e ideas que hoy surgen bajo el signo del archivo.

ABSTRACT The interaction of silver nanoparticles with Tomato seeds (Solanum Lycopersicum L.) was studied; the amount of silver uptake by tomato seeds was quantified by using flame atomic absorption. The absorption analysis was carried out according to the performance study of the method to estimate the detection and quantification limits as well as the accuracy. The seeds were exposed at different silver concentrations and different times. A simple method has been developed for the determination of silver content in aqueous matrices by acid digestion followed by atomic absorption spectroscopy flame; it was found that the acid digestion is efficient for extraction of the analyte in a single step. The limits of quantification achieved in the analytical method allow the determination of silver on plant tissue, the highest silver uptake in the tomato seeds was obtained with the treatment using the highest silver concentration (10 mM) and longer exposition time (48 h).

RESUMEN Se estudió la interacción de nanopartículas de plata con semillas de tomate (Solanum Lycopersicum L.); la cantidad de plata absorbida por las semillas se cuantificó usando absorción atómica de flama. Se realizó un estudio de rendimiento del método para determinar los límites de detección y de cuantificación así como la reproducibilidad. Las semillas se expusieron a diferentes concentraciones de plata y diferentes tiempos. Se desarrolló un método simple para la determinación del contenido de plata en matrices acuosas mediante digestión ácida seguida de espectroscopia de absorción atómica de flama; encontrándose que la digestión ácida es eficiente para la extracción del analito. Los límites de cuantificación obtenidos en el método analítico permiten la determinación de la plata en muestras de tejido vegetal, obtienendo la mayor absorción de plata en las semillas de tomate con el tratamiento de mayor concentración (10 mM) y mayor tiempo (48 h).

Abstract Due to its antimicrobial properties, silver has been used in many areas of medicine and today silver nanoparticles have been incorporated into different biomaterials. The objective of this study was to implement a simple method for the incorporation of silver nanoparticles in polymethyl methacrylate substrates, to determine their mechanical properties, antimicrobial functionality and the solubility of silver incorporated. Using this approach an antimicrobial material can be obtained; the surface of a commercial polymethyl methacrylate (Opti-cryl®) was impregnated with silver nanoparticles (AgNps) using a spray deposition method (0.03% by weight). The antimicrobial activity of the material was evaluated using the Japanese industrial standard (JIS Z 2801) against Escherichia coli and Staphylococcus aureus. Inductively coupled plasma optical spectrometry (ICP-OES) was used to measure the solubility of the incorporated silver nanoparticles. Mechanical tests of flexural strength were performed to observe changes in mechanical properties. The antimicrobial results show that PMMA / AgNps has significant antimicrobial activity, showing better results for Escherichia coli. ICP -OES analysis suggests low solubility in silver nanoparticles. Mechanical tests showed a 1.6% increase in flexural strength for PMMA added with silver nanoparticles. The method presented for incorporating silver nanoparticles into PMMA and producing an acrylic antimicrobial substrate is easy and has the advantage of improving its mechanical properties.

Why should we ask ourselves about Baroque-s meaning? In fact, ¿can we define it? During the 20th century -and specially for the last thirty years- Baroque has been one of the most studied and discussed issues. It remains an inevitable topic when thinking about Latin-American literary and critical history. Two questions have driven, mainly but unequally, its interest: one referred to its concept, the other to its corpus. Thus, the relations between concept and corpus -be they understated or self-evident- remain frequently unattended or implicit. This paper aims to reexamine and clarify the concept of Baroque following its critical drifts, specially the literary ones and mostly for Latin America. It also aims to thoughtfully analyze several excerpts from the work of sor Juana Inés de la Cruz (Mexico, 1648-1695) and from Juan de Espinosa Medrano (Peru, ¿1630?-1688) that makes it possible to properly analyze the relationship between concept and corpus. Finally, it aims to clarify this relationship and the critical conditions in which it emerged in order to think a possible distinction between the seventeenth Baroque and the twentieth (Neo)Baroque.

¿Tiene sentido preguntarse qué es el barroco? Y en cualquier caso, ¿puede definírselo? El barroco ha sido a lo largo del siglo XX y, con renovado impulso, en los últimos treinta años, un problema muy estudiado y discutido, e incluso inevitable a la hora de pensar la historia literaria y crítica latinoamericana. Dos cuestiones han guiado, central pero desigualmente, su interés: una, referente a su concepto; otra, pertinente a su corpus. Y así, es frecuente que la relación entre concepto y corpus, ya por sobreentendida ya por autoevidente, resulte desatendida o permanezca implícita. En este sentido, el presente trabajo se propone: revisar y precisar el concepto de barroco, atendiendo sus derivas críticas (especialmente literarias y principalmente para América Latina); analizar reflexivamente ciertos pasajes de la obra de sor Juana Inés de la Cruz (México, 1648-1695) y de Juan de Espinosa Medrano (Perú, ¿1630?-1688) que permitan una relación adecuada entre concepto y corpus; y por último, explicitar dicha relación y sus condiciones críticas de aparición a fin de pensar una posible distinción entre el barroco del siglo XVII y el (neo)barroco del XX.

Water soluble CdS nanoparticles were synthesized using a simple aqueous method that enables us to obtain functionalized nanoparticles with different sizes, optical absorption and emission features. These differences were reached using several Cd²+ to S2- molar ratios and various capping agents. The size of the nanoparticles ranges were from 2.6 to 3.88 nm depending on the synthesis conditions. CdS nanoparticles prepared could be used as biolabels because their nanometric dimensions, luminescence signal and most important to their functionalization with organic molecules, which have functional groups that can attach them to biomolecules or cells.

By using the theoretical model proposed by Mandelis et al. and a numerical simulations. We have analysed the generation of photoinduced black body radiation (photothermal radimometry signal) on monocrystalline silicon wafers. We report the particular role of each one of the main parameters involved on the phototermal signal. The parameter values were taken of the reported values for industrial silicon wafers. We show a discuss the obtained results.

Utilizando el modelo teórico propuesto por Mandelis et al. y mediante simulación numérica, se analiza detalladamente la generación de radiación de cuerpo negro foto-inducida (señal de radiometría fototérmica) en obleas de silicios monocristalino. Se reporta la influencia particular de dicha radiación en cada uno de los principales parámetros físicos involucrados. Los valores utilizados para estos parámetros están dentro de los rangos reportados para obleas de silicio industriales. Se presentan y discuten los resultados obtenidos.

We use a variation of the Rietveld refinement method to calculate the amorphous content of composites formed by a silica xerogel amorphous matrix and iron particles embedded into. In order to apply the Rietveld refinement to amorphous structures an initial crystalline model is assumed with the same composition as the material to be modelled. In this work we try to refine the structure of compounds using the program MAUD. It is shown how this program can be used to determine the amorphous and crystalline fractions in composites consisting of an amorphous matrix and incorporated iron oxide particles. The analysed compounds underwent different thermal treatments.

Se usa una variación del método de refinamiento Rietveld para calcular el porcentaje amorfo de compuestos formados por óxidos de fierro embebidos en una matriz amorfa de silica xerogel. Para refinar la estructura amorfa, se parte de un modelo cristalino con la misma composición del material que se va a modelar. En este trabajo se pretende refinar la estructura de los compuestos usando el programa MAUD. Se muestra que el programa puede ser usado para determinar las fracciones amorfas y cristalinas en compuestos que consisten de una matriz amorfa con incorporación de partículas de óxido de fierro. El análisis de fases se realiza en muestras con diferentes tratamientos térmicos.