Reseña de "Fronteras e identidades en Patagonia Central (1885-2007)"

Reseña de "Fronteras e identidades en Patagonia Central (1885-2007)", de Brígida Baeza, Rosario, Prohistoria ediciones, 2009. Colección Historia Argentina, 260 pp

Intrinsic noise profoundly alters the dynamics and steady state of morphogen-controlled bistable genetic switches

During tissue development, patterns of gene expression determine the spatial arrangement of cell types. In many cases, gradients of secreted signaling molecules - morphogens - guide this process. The continuous positional information provided by the gradient is converted into discrete cell types by the downstream transcriptional network that responds to the morphogen. A mechanism commonly used to implement a sharp transition between two adjacent cell fates is the genetic toggle switch, composed of cross-repressing transcriptional determinants. Previous analyses emphasize the steady state output of these mechanisms. Here, we explore the dynamics of the toggle switch and use exact numerical simulations of the kinetic reactions, the Chemical Langevin Equation, and Minimum Action Path theory to establish a framework for studying the effect of gene expression noise on patterning time and boundary position. This provides insight into the time scale, gene expression trajectories and directionality of stochastic switching events between cell states. Taking gene expression noise into account predicts that the final boundary position of a morphogen-induced toggle switch, although robust to changes in the details of the noise, is distinct from that of the deterministic system. Moreover, stochastic switching introduces differences in patterning time along the morphogen gradient that result in a patterning wave propagating away from the morphogen source. The velocity of this wave is influenced by noise; the wave sharpens and slows as it advances and may never reach steady state in a biologically relevant time. This could explain experimentally observed dynamics of pattern formation. Together the analysis reveals the importance of dynamical transients for understanding morphogen-driven transcriptional networks and indicates that gene expression noise can qualitatively alter developmental patterning

FT-ICR-MS approach to monitor asparagine deamidation and its isomers products in collagen from ancient bones

This project investigates the use of ultrahigh resolution mass spectrometry along with fragmentation techniques such as electron capture dissociation (ECD) and collisionally activated dissociation (CAD) to study deamidation of ancient bone, by using potential deamidation markers present in bovine collagen standards. With the application of these techniques, several marker peptides present in the digested protein standard of bovine collagen were successfully assigned. The sequences of these peptides correlated well with the reported sequences for bovine collagen in the literature. FT-ICR-MS was used to monitor deamidation of collagen by following a shift of +0.948 Da in the spectrum, resulting in a mass difference of 19 mDa from the 13C of the non-deamidated form and the 12C of the deamidated form, which can be difficult to assign due to overlap with the 13C isotopic distribution in peptides. The rate constants for the deamidation reaction were calculated, and the extent of deamidation before sample handling was determined. The methodology developed was then applied to collagen extracted from real bone samples, both modern and ancient, proving to be a useful method for monitoring asparagine deamidation before sample preparation. Differentiation of the isomers products of deamidation (aspartic and isoaspartic acid) were successfully assigned (where possible) using the diagnostic ions originated from their ECD spectra

El uso de herramientas lexicográficas ante problemas terminológicos: estrategias de profesores y estudiantes de ELE/EL2

Con el objetivo de contribuir al desarrollo de las estrategias de búsqueda lexicográfica de los estudiantes de español LE/L2, se realizó un estudio empírico para averiguar el uso concreto de recursos lexicográficos por parte tanto de profesores como de estudiantes. Con tal finalidad se observaron y anotaron los recursos usados, el orden de consulta y también las estrategias aplicadas por ambos grupos al realizar una traducción técnica del alemán al español. El análisis de los datos revela que existen pocas diferencias entre las estrategias de ambos grupos de usuarios: si bien los estudiantes realizan un mayor número de consultas y usan más recursos, no necesitan más tiempo que los profesores y además llegan a resultados similares respecto a la corrección de las traducciones. Todo ello apunta a que, antes de entrenar a los estudiantes de ELE en el manejo de recursos lexicográficos, es necesario capacitar al profesorado en su uso

Academic patents and entrepreneurial intention. To what extent are other knowledge transfer mechanisms affected in a Mexican university?

This research aims to expand the explanations about the debate on academic entrepreneurship and other knowledge transfer mechanisms, to respond to what extent entrepreneurial intention affects the diffusion and dissemination of knowledge in a Mexican university. The lack of indicators of commercial activity, leads us to propose the analysis of a pre-commercial stage of technology that we call entrepreneurial intention. After the literature review, we present a database of academic inventors in patents granted to the university, identifying patenting with an entrepreneurial intention, following Lomas (1993) knowledge transfer taxonomy. Data about publications and received citations by academic inventors is also considered for knowledge diffusion; as well as the supervision of end-of-degree projects in undergraduate and graduate studies; before and after the patent was granted, for knowledge dissemination. Using a binomial model, we estimated two data sets, one for the period 1984-2000 and the second for 2001-2020. Our findings reveal, an average increase of 60% in the number of patents obtained. We also found that the characteristics of the research group are significant in both models, but in the 2001-2020 period it is more important to integrate foreign inventors than patenting with firms, the dissemination of knowledge is more significant and has greater importance in the model. To respond to what extent entrepreneurial intention affects the diffusion and dissemination of knowledge, greater attention should be paid to the diffusion of knowledge since in both models the variable that represents publications after patenting is not significant. The explanation about the dissemination of knowledge improves substantially from one period to another

Trichogramma (Hymenoptera: Trichogrammatidae) Species, Egg Parasitoids of Diatraea saccharalis (Lepidoptera: Crambidae) on Sugarcane (Poales: Poaceae) in Argentina

The aim of this study was to identify egg parasitoids of Diatrea saccharalis F., sensu Guenée (Lepidoptera: Crambidae) in sugarcane in Tucumán, Argentina. We report a new host-parasitoid association of Trichogramma atopovirilia Oatman & Platner (Hymenoptera: Trichogrammatidae) attacking D. saccharalis and the first record of Trichogramma galloi Zucchi from Argentina. Additionally, Trichogramma pretiosum Riley was recorded in this survey.Fil: Isas, Marcos Gerardo. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Instituto de Tecnología Agroindustrial del Noroeste Argentino; ArgentinaFil: Luft Albarracin, Erica Beatriz. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; ArgentinaFil: Perez, Maria Lucia del Pilar. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Instituto de Tecnología Agroindustrial del Noroeste Argentino; ArgentinaFil: Salvatore, Analía. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; Argentin

Minimum Action Path theory reveals the details of stochastic biochemical transitions out of oscillatory cellular states

Cell state determination is the outcome of intrinsically stochastic biochemical reactions. Tran- sitions between such states are studied as noise-driven escape problems in the chemical species space. Escape can occur via multiple possible multidimensional paths, with probabilities depending non-locally on the noise. Here we characterize the escape from an oscillatory biochemical state by minimizing the Freidlin-Wentzell action, deriving from it the stochastic spiral exit path from the limit cycle. We also use the minimized action to infer the escape time probability density function

Characterization of attenuation parameters at a variety of scales in volcanic rocks

Seismic imaging through heterogeneous structures is especially challenging in volcanic environments, in which an important portion of the seismic data is attenuated by scattering and absorption. This thesis explores the connection between attenuation and scattering parameters with volcanic rock properties (petrophysical/mineralogical) and lays down the use of these parameters to develop new imaging techniques. The findings show the relevance of including stochastic attenuation parameters in the characterization of heterogeneous settings as a necessary step to interpret observations in the field

Flood lamination strategy based on a three-flood-diversion-area system management

The flood lamination has for principal objective to maintain a downstream flow at a fixed lamination level. For this goal, it is necessary to proceed to the dimensioning of the river system capacity and to make sure of its management by taking into account socio-economic and environmental constraints. The use of flood diversion areas on a river has for main interest to protect inhabited downstream areas. In this paper, a flood lamination strategy aiming at deforming the wave of flood at the entrance of the zone to be protected is presented. A transportation network modeling and a flow optimization method are proposed. The flow optimization method, is based on the modeling of a Min-Cost-Max-flow problem with a linear programming formulation. The optimization algorithm used in this method is the interior-point algorithm which allows a relaxation of the solution of the problem and avoids some non feasibility cases due to the use of constraints based on real data. For a forecast horizon corresponding to the flood episode, the management method of the flood volumes is evaluated on a 2D simulator of a river equipped with a three-flood-diversion- area system. Performances show the effectiveness of the method and its ability to manage flood lamination with efficient water storage