Globalización y competitividad económica en las ciudades de la región Centro Occidente de México en la última década del siglo XX

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Rho GTPases: regulation of cell polarity and growth in yeasts

11 páginas, 4 figuras, 1 tabla.-- El pdf del artículo es la versión post-print.Eukaryotic cells display a wide range of morphologies important for cellular function and development. A particular cell shape is made via the generation of asymmetry in the organization of cytoskeletal elements, usually leading to actin localization at sites of growth. The Rho family of GTPases is present in all eukaryotic cells, from yeast to mammals, and their role as key regulators in the signalling pathways that control actin organization and morphogenetic processes is well known. In the present review we will discuss the role of Rho GTPases as regulators of yeasts' polarized growth, their mechanism of activation and signalling pathways in Saccharomyces cerevisiae and Schizosaccharomyces pombe. These two model yeasts have been very useful in the study of the molecular mechanisms responsible for cell polarity. As in other organisms with cell walls, yeast's polarized growth is closely related to cell-wall biosynthesis, and Rho GTPases are critical modulators of this process. They provide the co-ordinated regulation of cell-wall biosynthetic enzymes and actin organization required to maintain cell integrity during vegetative growth.Work in the authors’ laboratory is supported by the Direcci-on General de Investigación, MICINN, Spain [grant number BFU2007-60675]; and the Junta de Castilla y León [grant number GR231].Peer reviewe

Integration of biophysical connectivity in the spatial optimization of coastal ecosystem services

Ecological connectivity in coastal oceanic waters is mediated by dispersion of the early life stages of marine organisms and conditions the structure of biological communities and the provision of ecosystem services. Integrated management strategies aimed at ensuring long-term service provision to society do not currently consider the importance of dispersal and larval connectivity. A spatial optimization model is introduced to maximise the potential provision of ecosystem services in coastal areas by accounting for the role of dispersal and larval connectivity. The approach combines a validated coastal circulation model that reproduces realistic patterns of larval transport along the coast, which ultimately conditions the biological connectivity and productivity of an area, with additional spatial layers describing potential ecosystem services. The spatial optimization exercise was tested along the coast of Central Chile, a highly productive area dominated by the Humboldt Current. Results show it is unnecessary to relocate existing management areas, as increasing no-take areas by 10% could maximise ecosystem service provision, while improving the spatial representativeness of protected areas and minimizing social conflicts. The location of protected areas was underrepresented in some sections of the study domain, principally due to the restriction of the model to rocky subtidal habitats. Future model developments should encompass the diversity of coastal ecosystems and human activities to inform integrative spatial management. Nevertheless, the spatial optimization model is innovative not only for its integrated ecosystem perspective, but also because it demonstrates that it is possible to incorporate time-varying biophysical connectivity within the optimization problem, thereby linking the dynamics of exploited populations produced by the spatial management regime.Comment: 30 pages, 5 figures, 2 tables; 1 graphical abstract. In this version: numbering of figures corrected, updated figure 2, typos corrected and references fixe

Spatial Regulation of Cdc42 During Cytokinesis

5 pages, 2 figures.-- PMID: 17637568 [PubMed].-- Printed version published on Jul 15, 2007.Cdc42 GTPase plays a critical role in the establishment of cell polarity in most eukaryotic organisms. Cdc42 active state, as that of other GTPases, depends on the bound nucleotide. The protein with GTP is active, and only in this state can it interact with different target effector proteins. The spatio-temporal control of Cdc42 activity is therefore necessary to generate growth polarity. In fission yeast cells, Cdc42 mainly localizes to the division area, and also to the growing tips and to some internal membranes. While the role of Cdc42 in apical growth is well defined, no role has been described for Cdc42 in the process of cell division. Fission yeast Cdc42 activity is regulated by two specific guanidine nucleotide exchange factors (GEFs), Scd1, and Gef1. We discuss here how Hob3, a BAR domain containing protein similar to human BIN3 and S. cerevisiae Rsv161, may be required to recruit Cdc42 to the cell division site as well as for the activation of this GTPase mediated by Gef1. We also discuss the possible role of Cdc42 in the contraction of the actomyosin ring necessary for cytokinesis.This work was supported by Grant BIO2004-0834 from the Comision Interministerial de Ciencia y Tecnología, Spain.Peer reviewe

Necesidades, intereses, barreras y atributos de un profesor investigador

Este trabajo da cuenta del proceso que se realizó durante un año, acerca de encontrar los elementos que constituyen a un profesor investigador, como las necesidades, intereses barreras y atributos, para lo cual se realizaron tres estudios de caso a tres profesoras de matemáticas de educación básica y media de Bogotá, realizando observaciones y entrevistas para recolectar información que posteriormente se analizarla y llegar a algunas conclusiones acerca de dichos elementos

David Wojnarowicz: la memoria y el peso del mundo

En el presente ensayo se aborda la dimensión política que pueden adquirir los géneros literarios de la autobiografía y el diario. Se analiza el caso particular del artista neoyorquino David Wojnarowicz, quien utilizó su práctica artística para cuestionar el manejo gubernamental de la crisis del VIH/SIDA durante los años ochenta y noventa en Estados Unidos. En el caso de Wojnarowicz el testimonio se convierte en una herramienta para renegociar la articulación de la memoria personal y la memoria colectiva y de igual manera confrontar la imposición de historias oficiales por parte de entramados institucionales. Desde una perspectiva interdisciplinaria, poniendo en contacto a la filosofía, las ciencias sociales, el arte y el análisis histórico, busco demostrar como la rememoración y la conmemoración son herramientas útiles para mantener una vigilancia constante ante las construcciones sociales que conllevan prácticas de estigmatización o que imponen prejuicios morales en contra de minorías

From downtown to the outskirts: A radio survey of the Orion Nebula Cluster

© The Author(s) 2021. Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.We present a newly enlarged census of the compact radio population towards the Orion Nebula Cluster (ONC) using high-sensitivity continuum maps (3-10 μ Jy beam-1) from a total of ∼30-h centimetre-wavelength observations over an area of ∼20 × 20 arcmin2 obtained in the C-band (4-8 GHz) with the Karl G. Jansky Very Large Array (VLA) in its high-resolution A-configuration. We thus complement our previous deep survey of the innermost areas of the ONC, now covering the field of view of the Chandra Orion Ultra-deep Project (COUP). Our catalogue contains 521 compact radio sources of which 198 are new detections. Overall, we find that 17 per cent of the (mostly stellar) COUP sources have radio counterparts, while 53 per cent of the radio sources have COUP counterparts. Most notably, the radio detection fraction of X-ray sources is higher in the inner cluster and almost constant for r > 3 arcmin (0.36 pc) from θ1 Ori C, suggesting a correlation between the radio emission mechanism of these sources and their distance from the most massive stars at the centre of the cluster, e.g. due to increased photoionisation of circumstellar discs. The combination with our previous observations 4 yr prior lead to the discovery of fast proper motions of up to ∼373 km s-1 from faint radio sources associated with ejecta of the OMC1 explosion. Finally, we search for strong radio variability. We found changes in flux density by a factor of ≲5 within our observations and a few sources with changes by a factor >10 on long time-scales of a few years.Peer reviewe

Using the equivalent material concept and the average strain energy density to analyse the fracture behaviour of structural materials

ABSTRACT: This paper provides a complete overview of the applicability of the Equivalent Material Concept in conjunction with the Average Strain Energy Density criterion, to provide predictions of fracture loads in structural materials containing U-notches. The Average Strain Density Criterion (ASED) has a linear-elastic nature, so in principle, it does not provide satisfactory predictions of fracture loads in those materials with nonlinear behaviour. However, the Equivalent Material Concept (EMC) is able to transform a physically nonlinear material into an equivalent linear-elastic one and, therefore, the combination of the ASED criterion with the EMC (EMC?ASED criterion) should provide good predictions of fracture loads in physically nonlinear materials. The EMC?ASED criterion is here applied to different types of materials (polymers, composites and metals) with different grades of nonlinearity, showing the accuracy of the corresponding fracture load predictions and revealing qualitatively the limitations of the methodology. It is shown how the EMC?ASED criterion provides good predictions of fracture loads in nonlinear materials as long as the nonlinear behaviour is mainly limited to the tensile behaviour, and how the accuracy decreases when the nonlinear behaviour is extended to the material behaviour in the presence of defectsFunding: This research was funded by the Spanish Ministry of Science, Innovation and Universities, grant number PGC2018-095400-B-I00 (MCIU/AEI/FEDER, UE)