60 research outputs found

    Una primera reflexión sobre la reforma energética

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    De cara a la reforma energética era difícil pensar en una reestructuración de Pemex o del sector de energía en México. Una verdadera reestructuración hubiera exigido, y exige todavía, un aliento continuo, fundamental, vigoroso, radical hacia nuevos patrones de resolución de las necesidades de transporte de personas y mercancías; nuevos patrones de construcción con iluminación natural creciente y, en general, de todas las formas útiles de energía. Es una de las tareas impostergables y más urgentes de la sociedad.ITESO, A.C

    Una primera reflexión sobre la reforma energética

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    De cara a la reforma energética era difícil pensar en una reestructuración de Pemex o del sector de energía en México. Una verdadera reestructuración hubiera exigido, y exige todavía, un aliento continuo, fundamental, vigoroso, radical hacia nuevos patrones de resolución de las necesidades de transporte de personas y mercancías; nuevos patrones de construcción con iluminación natural creciente y, en general, de todas las formas útiles de energía. Es una de las tareas impostergables y más urgentes de la sociedad.ITESO, A.C

    La constitución y la reforma energética. Notas para un debate

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    La discusión en México sobre la denominada reforma energética tiene como antecedente más de 20 años de deliberación nacional e internacional en torno a la naturaleza y función del estado frente a la promoción del desarrollo económico. Se trata de un debate que ha abrevado sus principales ideas de los cuestionamientos globales del estado de bienestar; de objetar, aunque la mayoría de las veces atacar, el sistema económico, social y político en el cual la promoción de ese bienestar compete a la administración pública, lo que, como señalan muchos autores, supone formas específicas de articulación y organización institucional y territorial a través de las que se ejerce y cumple esa responsabilidad. El autor aporta a la discusión desde el análisis de lo que establece la Constitución mexicana.ITESO, A.C

    Winter diet of the long-eared owl Asio otus (Strigiformes: Strigidae) in the grasslands of Janos, Chihuahua, Mexico

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    Abstract Background: The long-eared owl (Asio otus) has a Holarctic distribution, including much of North America. This nocturnal species is considered to be extremely secretive, and poorly known in the Great Plains of the United States and Canada, as well as to México, where no previous studies on its diet have been conducted. Findings: We analyzed 120 pellets collected during January 2007 in roosts in a 2–3 m height mesquite scrub within a grassland area of Reserva Ecológica El Uno, located in the Natural Protected Area Janos. We registered and identified three orders, four families, eight genera and ten species of mammals and two orders and one family of insects. Winter diet is dominated by mammals, especially rodents in both frequency and biomass. Cricetidae and Perognathus flavus were the most frequent family and species, respectively. On the other hand, when analyzing biomass, Sigmodon species were dominant, achieving almost 70% of the consumed biomass. Levin's standardized niche breath based on frequency was calculated as 0.40, while based on biomass was 0.38. Also, two previously unrecorded rodent species were identified as long-eared owl prey. Conclusion: Although 18 different types of items were identified, the long-eared owl tends to be selective, with a single genera (Sigmodon) comprising almost 70% of its consumed biomass during winter. Perognathus flavus was also important in frequency (21%); however, it barely constitutes 2% of the consumed biomass. Keywords: Winter diet, Long-eared owl, Grasslands, Janos, México Resumen El búho orejas largas es una especie Holártica, que se distribuye en gran parte de Norteamérica y que ha sido poco estudiada, especialmente en las Grandes Planicies de Estados Unidos y en México, donde no existe un estudio previo sobre su dieta invernal. Se colectaron y analizaron 120 egagrópilas en la Reserva Ecológica El Uno, dentro del Área Natural Protegida Reserva de la Biósfera Janos. Se identificaron un total de 18 tipos de presa, pero la especie mostró selectividad por dos géneros/especies, ya que cerca del 70% de la biomasa consumida fueron especies del género Sigmodon, mientras que el 21% de las muestras contenían Perognathus flavus. Además, dos especies de roedores identificadas constituyen nuevos registros de presa para la especie

    Building and surroundings: thermal coupling

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    Energy building performance can be different according to outdoor conditions or urban environment, at the same time that this last assess, buildings are also affected by the building envelope, as obvious consequence of the thermal and Aeraulic coupling existing between the indoor and outdoor conditions in buildings. Thus, in this coupling is fundamental to typify the transmission phenomenon through the building envelope. Doing this, it is possible to estimate transmission heating losses and gains and also the superficial temperatures of the envelope. In order to assess the transient behaviour of the building envelope it is necessary to develop a predictive model, precise enough, to be integrated in a simulating tool. Detailed and multidimensional models, based in numerical methods, like Finite Element Method (FEM), has a high precision, but its complexity imply resources consumption and computational time, too high to be integrated in these kind of tools. On the contrary, simplified methods are good enough because they are simple and fast, with an acceptable precision in almost all the situations. The present work is focused: (a) Firstly, to develop a simplified RC-network model. The aim of the model is to characterize and to implement with precision the behaviour of a wall in a simulating software tool based on urban environment, (b) secondly, to express in form of equivalences, the different indoor and outdoor excitations that can exist in the building envelope, and (c) finally, to calibrate the simplified model through its characteristic parameters. For a homogeneous wall and two types of excitations, it has been obtained the characteristic parameters of the model that represent the better adjustment to the real wall. In a first step, it has been obtained the results of the proposal model and a reference model based on FEM, in terms of wall external surface heat flow. Results of both models have been compared, and the resultant characteristic parameters of the model have been obtained through an optimisation method. Results for the wall and for the excitations under analysis show: (1) Characteristic longitude ec, or capacitive node position, it is determined according to a certain value of Fo equal to 2 for both excitations, this value remains constant in time, (2) useful wall thickness, on the contrary, vary as time function, according to a logarithmic law for both excitations, although this function is different depending on the considered excitation, (3) using a constant excitation, coefficients from the previous logarithmic function depends on the range of the excitation, while these are practically independent of the lineal excitation gradient

    Transiciones, conflictos y democracia : estudios de coyuntura

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    México ha vivido un largo proceso de transición que ha desencadenado dinamismos económicos, culturales y políticos. En la actual coyuntura, estos dinamismos muestran toda su complejidad, su inevitable articulación y la tensión entre las fuerzas que intentan sostener un viejo modelo de gobernar y decidir el rumbo del país, y aquellas que buscan abrirse a un espectro mucho más amplio y diversificado de actores. En ellos se conjuntan las aspiraciones más legítimas de los mexicanos por avanzar en el reconocimiento y respeto de la pluralidad étnica, de género y entre generaciones, y por impulsar una dinámica en la que —en medio de los procesos de mundialización— los distintos grupos e intereses de los mexicanos puedan ser incluidos. La transición mexicana tiende a centrarse en la dimensión política. La intensidad que cobran los procesos políticos y el énfasis que importantes analistas ponen en dichos procesos, contribuyen a que esta asociación vaya cobrandoíuerza. En este sentido, es necesario advertir que en las transiciones la tendencia privatizadora, la reducción del gasto social, así como la necesidad de pactos sociales que sean respetados, la participación creciente de la sociedad civil, etc. son factores importantes que, en medio de contradicciones, van generando nuevos esquemas de relación entre gobierno y sociedad.ITESO, A.C

    Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

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    The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

    Contributions of mean and shape of blood pressure distribution to worldwide trends and variations in raised blood pressure: A pooled analysis of 1018 population-based measurement studies with 88.6 million participants

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    © The Author(s) 2018. Background: Change in the prevalence of raised blood pressure could be due to both shifts in the entire distribution of blood pressure (representing the combined effects of public health interventions and secular trends) and changes in its high-blood-pressure tail (representing successful clinical interventions to control blood pressure in the hypertensive population). Our aim was to quantify the contributions of these two phenomena to the worldwide trends in the prevalence of raised blood pressure. Methods: We pooled 1018 population-based studies with blood pressure measurements on 88.6 million participants from 1985 to 2016. We first calculated mean systolic blood pressure (SBP), mean diastolic blood pressure (DBP) and prevalence of raised blood pressure by sex and 10-year age group from 20-29 years to 70-79 years in each study, taking into account complex survey design and survey sample weights, where relevant. We used a linear mixed effect model to quantify the association between (probittransformed) prevalence of raised blood pressure and age-group- and sex-specific mean blood pressure. We calculated the contributions of change in mean SBP and DBP, and of change in the prevalence-mean association, to the change in prevalence of raised blood pressure. Results: In 2005-16, at the same level of population mean SBP and DBP, men and women in South Asia and in Central Asia, the Middle East and North Africa would have the highest prevalence of raised blood pressure, and men and women in the highincome Asia Pacific and high-income Western regions would have the lowest. In most region-sex-age groups where the prevalence of raised blood pressure declined, one half or more of the decline was due to the decline in mean blood pressure. Where prevalence of raised blood pressure has increased, the change was entirely driven by increasing mean blood pressure, offset partly by the change in the prevalence-mean association. Conclusions: Change in mean blood pressure is the main driver of the worldwide change in the prevalence of raised blood pressure, but change in the high-blood-pressure tail of the distribution has also contributed to the change in prevalence, especially in older age groups

    Repositioning of the global epicentre of non-optimal cholesterol

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    High blood cholesterol is typically considered a feature of wealthy western countries(1,2). However, dietary and behavioural determinants of blood cholesterol are changing rapidly throughout the world(3) and countries are using lipid-lowering medications at varying rates. These changes can have distinct effects on the levels of high-density lipoprotein (HDL) cholesterol and non-HDL cholesterol, which have different effects on human health(4,5). However, the trends of HDL and non-HDL cholesterol levels over time have not been previously reported in a global analysis. Here we pooled 1,127 population-based studies that measured blood lipids in 102.6 million individuals aged 18 years and older to estimate trends from 1980 to 2018 in mean total, non-HDL and HDL cholesterol levels for 200 countries. Globally, there was little change in total or non-HDL cholesterol from 1980 to 2018. This was a net effect of increases in low- and middle-income countries, especially in east and southeast Asia, and decreases in high-income western countries, especially those in northwestern Europe, and in central and eastern Europe. As a result, countries with the highest level of non-HDL cholesterol-which is a marker of cardiovascular riskchanged from those in western Europe such as Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland and Malta in 1980 to those in Asia and the Pacific, such as Tokelau, Malaysia, The Philippines and Thailand. In 2017, high non-HDL cholesterol was responsible for an estimated 3.9 million (95% credible interval 3.7 million-4.2 million) worldwide deaths, half of which occurred in east, southeast and south Asia. The global repositioning of lipid-related risk, with non-optimal cholesterol shifting from a distinct feature of high-income countries in northwestern Europe, north America and Australasia to one that affects countries in east and southeast Asia and Oceania should motivate the use of population-based policies and personal interventions to improve nutrition and enhance access to treatment throughout the world.Peer reviewe
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