Chiapas : entre el autoritarismo y la transición democrática, desde Acteal hasta el diálogo EZLN y sociedad civil

Obra cuya intención es dar cuenta de los diversos actores sociales involucrados en el conflicto de Chiapas, a nivel político, económico y sociocultural. El texto recupera un taller de análisis de coyuntura sobre el tema, realizado en agosto de 1998.ITESO, A.C

Estudio físico, químico y microestructural de geopolímeros base ceniza volante

En este trabajo se analizó el comportamiento físico, químico y microestructural de la ceniza volante activada alcalinamente. Para ello fueron utilizados diferentes tamaños de partícula de ceniza volante (CV), obtenidos por molienda manual, mezcladas con NaOH y curadas durante 7, 14 y 28 días. Las técnicas de caracterización utilizadas fueron: TGA, FTIR, MEB, adsorción física de gases y pruebas de resistencia a compresión, además del software NIVision Assistant. Los resultados muestran que la disminución de tamaño de partículas, favoreció la geopolimerización del gel N-A-S-H y mejoró las propiedades cementantes en los geopolímeros, logrando resistencias a compresión hasta de 23 MPa, por otro lado, se indica mediante análisis de imagen, que los porcentajes de porosidad en cada uno de los morteros evaluados disminuyen conforme se alejan de la zona de transición interfacial (ZTI), los cuales se corroboran con los resultados de porosimetría. (ANGLÈS) In this paper was analyzed the physical, chemical and microstructural behavior of alkali activated fly ash. This comparison was used with different particle sizes of fly ash (CV), obtained by manual milling, mixed with NaOH and cured for 7, 14 and 28 days. The characterization techniques used: TGA, FTIR, SEM, physical adsorption of gases and compressive strength tests, as well NIVision Assistant software. The results show that decreasing particle size favored NASH gel Geopolymerization and improved cementitious properties in geopolymer, achieving compressive strengths up to 23 MPa. On the other hand, indicated by image analysis, the percentages of porosity in each of the mortars evaluated decrease as they move away from the interfacial transition zone (ZTI), these results are corroborated by porosimetry method.Peer ReviewedPostprint (published version

The Galaxy Activity, Torus, and Outflow Survey (GATOS): III. Revealing the inner icy structure in local active galactic nuclei

We use JWST/MIRI MRS spectroscopy of a sample of six local obscured type 1.9/2 active galactic nuclei (AGN) to compare their nuclear mid-IR absorption bands with the level of nuclear obscuration traced by X-rays. This study is the first to use subarcsecond angular resolution data of local obscured AGN to investigate the nuclear mid-IR absorption bands with a wide wavelength coverage (4.9–28.1 μm). All the nuclei show the 9.7 μm silicate band in absorption. We compare the strength of the 9.7 and 18 μm silicate features with torus model predictions. The observed silicate features are generally well explained by clumpy and smooth torus models. We report the detection of the 6 μm dirty water ice band (i.e., a mix of water and other molecules such as CO and CO2) at subarcsecond scales (∼0.26″ at 6 μm; inner ∼50 pc) in a sample of local AGN with different levels of nuclear obscuration in the range log NHX-Ray (cm−2)∼22 − 25. We find good correlation between the 6 μm water ice optical depths and NHX-Ray. This result indicates that the water ice absorption might be a reliable tracer of the nuclear intrinsic obscuration in AGN. The weak water ice absorption in less obscured AGN (log NHX-ray (cm−2)≲23.0 cm−2) might be related to the hotter dust temperature (> TsubH2O ∼ 110 K) expected to be reached in the outer layers of the torus due to their more inhomogeneous medium. Our results suggest it might be necessary to include the molecular content, such as H2O, aliphatic hydrocarbons (CH−), and more complex polycyclic aromatic hydrocarbon (PAH) molecules, in torus models to better constrain key parameters such as the torus covering factor (i.e., nuclear obscuration)

Minimising Mortality in Endangered Raptors Due to Power Lines: The Importance of Spatial Aggregation to Optimize the Application of Mitigation Measures

Electrocution by power lines is one of the main causes of non-natural mortality in birds of prey. In an area in central Spain, we surveyed 6304 pylons from 333 power lines to determine electrocution rates, environmental and design factors that may influence electrocution and the efficacy of mitigation measures used to minimise electrocution cases. A total of 952 electrocuted raptors, representing 14 different species, were observed. Electrocuted raptors were concentrated in certain areas and the environmental factors associated with increased electrocution events were: greater numbers of prey animals; greater vegetation cover; and shorter distance to roads. The structural elements associated with electrocutions were shorter strings of insulators, one or more phases over the crossarm, cross-shaped design and pylon function. Of the 952 carcasses found, 148 were eagles, including golden eagle (Aquila chrysaetos), Spanish imperial eagle (Aquila adalberti) and Bonelli's eagle (Aquila fasciata). Electrocuted eagles were clustered in smaller areas than other electrocuted raptors. The factors associated with increased eagle electrocution events were: pylons function, shorter strings of insulators, higher slopes surrounding the pylon, and more numerous potential prey animals. Pylons with increased string of insulators had lower raptor electrocution rates than unimproved pylons, although this technique was unsuccessful for eagles. Pylons with cable insulation showed higher electrocution rates than unimproved pylons, both for raptors and eagles, despite this is the most widely used and recommended mitigation measure in several countries. To optimize the application of mitigation measures, our results recommend the substitution of pin-type insulators to suspended ones and elongating the strings of insulators

A PSTOL-like gene, TaPSTOL, controls a number of agronomically important traits in wheat

Background Phosphorus (P) is an essential macronutrient for plant growth, and is required in large quantities by elite varieties of crops to maintain yields. Approximately 70% of global cultivated land suffers from P deficiency, and it has recently been estimated that worldwide P resources will be exhausted by the end of this century, increasing the demand for crops more efficient in their P usage. A greater understanding of how plants are able to maintain yield with lower P inputs is, therefore, highly desirable to both breeders and farmers. Here, we clone the wheat (Triticum aestivum L.) homologue of the rice PSTOL gene (OsPSTOL), and characterize its role in phosphate nutrition plus other agronomically important traits. Results TaPSTOL is a single copy gene located on the short arm of chromosome 5A, encoding a putative kinase protein, and shares a high level of sequence similarity to OsPSTOL. We re-sequenced TaPSTOL from 24 different wheat accessions and (3) three T. durum varieties. No sequence differences were detected in 26 of the accessions, whereas two indels were identified in the promoter region of one of the durum wheats. We characterised the expression of TaPSTOL under different P concentrations and demonstrated that the promoter was induced in root tips and hairs under P limiting conditions. Overexpression and RNAi silencing of TaPSTOL in transgenic wheat lines showed that there was a significant effect upon root biomass, flowering time independent of P treatment, tiller number and seed yield, correlating with the expression of TaPSTOL. However this did not increase PUE as elevated P concentration in the grain did not correspond to increased yields. Conclusions Manipulation of TaPSTOL expression in wheat shows it is responsible for many of the previously described phenotypic advantages as OsPSTOL except yield. Furthermore, we show TaPSTOL contributes to additional agronomically important traits including flowering time and grain size. Analysis of TaPSTOL sequences from a broad selection of wheat varieties, encompassing 91% of the genetic diversity in UK bread wheat, showed that there is very little genetic variation in this gene, which would suggest that this locus may have been under high selection pressure

How to move ionized gas: an introduction to the dynamics of HII regions

This review covers the dynamic processes that are important in the evolution and structure of galactic HII regions, concentrating on an elementary presentation of the physical concepts and recent numerical simulations of HII region evolution in a non-uniform medium. The contents are as follows: (1) The equations (Euler equations; Radiative transfer; Rate equations; How to avoid the dynamics; How to avoid the atomic physics). (2) Physical concepts (Static photoionization equilibrium; Ionization front propagation; Structure of a D-type front; Photoablation flows; Other ingredients - Stellar winds, Radiation pressure, Magnetic fields, Instabilities). (3) HII region evolution (Early phases: hypercompact and ultracompact regions; Later phases: compact and extended regions; Clumps and turbulence).Comment: To be published as a chapter in 'Diffuse Matter from Star Forming Regions to Active Galaxies' - A volume Honouring John Dyson. Eds. T. W. Harquist, J. M. Pittard and S. A. E. G. Falle. 25 pages, 7 figures. Some figures degraded to meet size restriction. Full-resolution version available at http://www.ifront.org/wiki/Dyson_Festschrift_Chapte

Analysis of changes in the association of income and the utilization of curative health services in Mexico between 2000 and 2006

<p>Abstract</p> <p>Background</p> <p>A common characteristic of health systems in most developing countries is unequal access to health services. As a result, members of the poorest population groups often do not receive formal attention for health services, because they cannot afford it. In 2001 in Mexico, to address income-related differences in the use of health services, the government launched a major healthcare reform, which includes a health insurance program called <it>Seguro Popular</it>, aimed at improving healthcare access among poor, uninsured residents. This paper analyzes the before and after changes in the demand for curative ambulatory health services focusing on the association of income-related characteristics and the utilization of formal healthcare providers vs. no healthcare service utilization.</p> <p>Methods</p> <p>By using two nationally representative health surveys (ENSA-2000 and ENSANUT-2006), we modeled an individual's decision when experiencing an illness to use services provided by the (1) Ministry of Health (MoH), (2) social security, (3) private entities, or (4) to not use formal services (no healthcare service utilization).</p> <p>Results</p> <p>Poorer individuals were more likely in 2006 than in 2000 to respond to an illness by using formal healthcare providers. Trends in provider selection differed, however. The probability of using public services from the MoH increased among the poorest population, while the findings indicated an increase in utilization of private health services among members of low- and middle-income groups. No significant change was seen among formal workers -covered by social security services-, regardless of socioeconomic status.</p> <p>Conclusions</p> <p>Overall, for 2006 the Mexican population appears less differentiated in using healthcare across economic groups than in 2000. This may be related, in part, to the implementation of <it>Seguro Popular</it>, which seems to be stimulating healthcare demand among the poorest and previously uninsured segment of the population. Still, public health authorities need to address the remaining income-related healthcare utilization differences, the differences in quality between public and private health services, and the general perception that MoH facilities offer inferior services.</p

New records of ray-finned fishes (Actinopterygii) from Puerto Morelos Reef National Park (Mexican Caribbean)

We documented the nearshore ray-finned fishes in Puerto Morelos Reef National Park (PMRNP) by sampling 57 localities, including rocky intertidal pools, sandy bottoms, Thalassia beds, coral reefs, artificial reefs, karstic-slab bottoms, demersal-pelagic areas, and sessile-Sargassum patches. We recorded seven species new to Caribbean Mexican waters and one hundred and six species new to the PMRNP, most of which are small cryptobenthic reef fish. The resultant checklist includes 349 species, and specimens of 285 of which (81.7%) have been deposited in an ichthyological museum collection. These include both voucher organisms and with tissue samples for genetic analysis. A comparison with inventories at other localities of the Greater Caribbean indicates that more targeted sampling for cryptobenthic and deep-reef fishes is needed to provide a complete inventory. We also comment on the local use of some species as fishery resources