<p>La caña de azúcar es una de las más importante actividades productivas en la región Huasteca de México y que requiere de planes para incrementar la productividad y disminuir la incertidumbre ante las limitaciones y el mercado. Mediante la zonificación productiva potencial del cultivo a través de una evaluación multicriterio AHP (proceso de jerarquías analíticas) en un ambiente SIG (Imgenes Lansat 7 ETM+), se generaron mapas temáticos (climáticos y edafológicos) relacionados con las variables del cultivo de caña empleando ILWIS y ESRI ArcGis 9.2. La metodología AHP proporcionó el marco de evaluación y la zonificación del cultivo al sintetizar la interacción entre las variables que determinan la productividad del cultivo y representan el punto clave del manejo agronómico espacial en Huasteca. Los resultados demostraron que la metodología de percepción remota, AHP y SIG, pueden servir además como herramienta efectiva, de bajo costo.</p><p> </p><p><strong>Multicriteria evaluation and agro-climatic suitability of growing sugar cane in the Huasteca region of Mexico</strong></p><p>Sugarcane production is one of the most important activities in the Huasteca region of Mexico, which requires plans to increase productivity and reduce uncertainty caused by limitations and the market. By zoning the crop using a multi-criteria evaluation AHP (analytic hierarchy process) in GIS (Landsat 7 ETM+), thematic maps (climate and soil) were generated associated with the variables of cane using ILWIS and ESRI ArcGIS 9.2. The AHP methodology provides a framework for assessing and zoning the crop in order to synthesize the interaction between the variables that determine crop productivity and represent the key point of agronomic management of space in Huasteca. The results showed that the methodology of remote sensing, GIS and AHP, can also serve as an effective, low cost tool.</p>

Las especies del género Dendroctonus son parásitos específicos de bosques de coníferas (Pinaceae- Coniferales), de tal forma que su distribución geográfica está asociada con estas comunidades boscosas. La coexistencia natural entre las especies de Dendroctonus normalmente ocurre entre aquellas que presentan diferencias ecológicas, morfológicas y reproductivas evidentes; sin embargo, algunas observaciones realizadas en condiciones naturales, sugieren la coexistencia en espacio y tiempo entre algunas especies con atributos biológicos semejantes. El objetivo del presente trabajo fue determinar las zonas de sobreposición de las especies de Dendroctonus en México, por medio de registros de colecta obtenidos de las principales colecciones entomológicas del país. Se elaboraron mapas de distribución geográfica por estado, y a partir de ellos se delimitaron las áreas de sobreposición por el método de la propincuidad media. Los resultados muestran la presencia de 27 áreas de sobreposición de dos a cinco especies, las que coinciden en latitud, longitud, altitud y huésped. La presencia de estas zonas sugiere que la posible coexistencia de especies de Dendroctonus con atributos biológicos semejantes puede ser común y que debería considerarse en los programas de control de estos insectos. Además, plantea la posibilidad de estudiar diversos fenómenos ecológico- evolutivos que pueden presentarse en éstas especies en estos sitios.

In this work, the effect of the chemical modification of titanium dioxide particles on the non-isothermal crystallization process of polylactic acid (PLA) was studied. Cold crystallization in some polymers occurs above the glass transition temperature (Tg) when the polymer chains gain sufficient mobility to organize themselves into the ordered structure (i.e. the crystal structure) by folding the chains. Cold crystallization in general is caused by the ordering of the molecular chains in the crystalline PLA due to the increased mobility during heating. Through an analysis of the cool crystallization process in DSC at different cooling rates, it was observed that the behavior of PLA and its composites made with titanium dioxide, neat and functionalized with dicarboxylic acids, can be described through the models used for crystallization of the polymer carrying out during cooling, such as Mo’s and Jeziorny’s model. In addition, it was determined that the chemical modification of TiO2 performed with silane increases the crystallization rate in the last step of the process; while the chemical modification with dicarboxylic acid has an accelerated effect on the crystal formation process attributed to the affinity between the aliphatic part of this group and the polymer chains. Also, it was shown that the inclusion of the silanized particles has no effect on the energy requirement compared to the pure PLA process; however, the addition of particles with the dicarboxylic acid decreases the energy value required to complete the crystalline state due to affinity at the surface to immobilize the polymer chains. Finally, it is emphasized that the activation energy required to perform the crystallization of PLA and its composites has positive values, which is an indicator that the crystallization was performed while heating, after reaching and passing the glass transition temperature and before melting.

Carriers of the FMR1 premutation (PM) allele are at risk of one or more clinical conditions referred to as FX premutation-associated conditions (FXPAC). Since the FMR1 gene is on the X chromosome, the activation ratio (AR) may impact the risk, age of onset, progression, and severity of these conditions. The aim of this study was to evaluate the reliability of AR measured using different approaches and to investigate potential correlations with clinical outcomes. Molecular and clinical assessments were obtained for 30 PM female participants, and AR was assessed using both Southern blot analysis (AR-Sb) and methylation PCR (AR-mPCR). Higher ARs were associated with lower FMR1 transcript levels for any given repeat length. The higher AR-Sb was significantly associated with performance, verbal, and full-scale IQ scores, confirming previous reports. However, the AR-mPCR was not significantly associated (p > 0.05) with these measures. Similarly, the odds of depression and the number of medical conditions were correlated with higher AR-Sb but not correlated with a higher AR-mPCR. This study suggests that AR-Sb may be a more reliable measure of the AR in female carriers of PM alleles. However, further studies are warranted in a larger sample size to fully evaluate the methylation status in these participants and how it may affect the clinical phenotype.

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