Jerarquía funcional y urbana entre las zonas metropolitanas de la región Centro Occidente de México en el contexto de la globalización

Peer Reviewe

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

Peer Reviewe

Kernel PCA for multivariate extremes

We propose kernel PCA as a method for analyzing the dependence structure of multivariate extremes and demonstrate that it can be a powerful tool for clustering and dimension reduction. Our work provides some theoretical insight into the preimages obtained by kernel PCA, demonstrating that under certain conditions they can effectively identify clusters in the data. We build on these new insights to characterize rigorously the performance of kernel PCA based on an extremal sample, i.e., the angular part of random vectors for which the radius exceeds a large threshold. More specifically, we focus on the asymptotic dependence of multivariate extremes characterized by the angular or spectral measure in extreme value theory and provide a careful analysis in the case where the extremes are generated from a linear factor model. We give theoretical guarantees on the performance of kernel PCA preimages of such extremes by leveraging their asymptotic distribution together with Davis-Kahan perturbation bounds. Our theoretical findings are complemented with numerical experiments illustrating the finite sample performance of our methods

A Linear Time Algorithm for Counting #2SAT on Series-Parallel Formulas

Capítulo de libroAn O(m + n) time algorithm is presented for counting the number of models of a two Conjunctive Normal Form Boolean Formula whose constrained graph is represented by a Series-Parallel graph, where n is the number of variables and m is the number of clauses. To the best of our knowledge, no linear time algorithm has been developed for counting in this kind of formulas

Anthocyanins: Molecular Aspects on Their Neuroprotective Activity

Anthocyanins are a type of flavonoids that give plants and fruits their vibrant colors. They are known for their potent antioxidant properties and have been linked to various health benefits. Upon consumption, anthocyanins are quickly absorbed and can penetrate the blood-brain barrier (BBB). Research based on population studies suggests that including anthocyanin-rich sources in the diet lower the risk of neurodegenerative diseases. Anthocyanins exhibit neuroprotective effects that could potentially alleviate symptoms associated with such diseases. In this review, we compiled and discussed a large body of evidence supporting the neuroprotective role of anthocyanins. Our examination encompasses human studies, animal models, and cell cultures. We delve into the connection between anthocyanin bioactivities and the mechanisms underlying neurodegeneration. Our findings highlight how anthocyanins\u27 antioxidant, anti-inflammatory, and anti-apoptotic properties contribute to their neuroprotective effects. These effects are particularly relevant to key signaling pathways implicated in the development of Alzheimer\u27s and Parkinson\u27s diseases. In conclusion, the outcome of this review suggests that integrating anthocyanin-rich foods into human diets could potentially serve as a therapeutic approach for neurological conditions, and we identify promising avenues for further exploration in this area

La administración de los materiales en proyectos de edificación mediante modelos BIM

La construcción consiste en la transformación de materiales elaborados y semielaborados en cantidades relativamente grandes donde entre el 50 al 60% de los costos directos de las obras medianas y pequeñas de edificación corresponden a los materiales. La manera tradicional de gestionar los materiales se enfoca a las actividades en sitio y logística, dándole menos importancia a la información generada durante el proceso de gestión de materiales y la disponibilidad hacia las partes involucradas, existiendo deficiencias y problemas relacionados a la compra, suministro en tiempo y forma, logística en sitio, información actualizada y disponible del estado de los materiales, entre otros. Por otro lado, la tecnología Building Information Modeling (BIM por sus siglas en inglés; Modelado de la Información para la Edificación, en español) es una plataforma tecnológica que tiene la capacidad de asociar las características e información de los materiales a los elementos y componentes del proyecto, así como la fácil actualización del modelo BIM con respecto al desenvolvimiento de la edificación. BIM tiene el potencial de facilitar la gestión de los materiales mediante la integración de la información que se requiere a lo largo del proceso de gestión de los materiales. El objetivo general de esta investigación consiste en establecer un marco de referencia para la realización de la administración de los materiales en proyectos de edificación mediante modelos BIM

Improved diagnostics and surveillance identify novel reassortant swine influenza A viruses in Chile

Influenza A Virus (IAV) circulates endemically in nature, representing a constant concern to public health and animal production systems worldwide. The emergence of the 2009 H1N1 influenza A pandemic (A(H1N1)pdm09) highlighted the need of conducting systematic surveillance studies, and evidenced the significant gap of knowledge of the swine IAVs (SwIAV) circulating in pigs worldwide at the time of the outbreak. This also highlighted the role of swine as important reservoirs for the generation of endemic strains with zoonotic and pandemic potential. Despite this, comprehensive information of SwIAV circulating in Latin America is still lacking. While Chile has strong ecological barriers and high stringency controls regarding livestock trading, IAV is endemic and has been consistently detected in pigs. This has caused great concerns for the swine industry, because of the on-going clinical and production losses. Nevertheless, few surveillance efforts have been conducted in Chile and there is limited information regarding the genetic diversity and origin of swIAVs. Determining the viral subtypes and genotypes circulating in swine is key for the development of appropriate vaccine approaches and control measures for the swine industry, and it is crucial for identifying novel strains with pandemic potential. We developed improved diagnostic tools to detect endemic viruses and characterized the diversity and origin of SwAIV and its prevalence in Chilean swine production farms. From December 2013 to June 2015, we sampled 27 farms representative of intensive swine production systems located between the Valparaiso and Araucania administrative regions. Animals were mainly found to be susceptible to IAV infection at 50 to 110 days of age. Serological analysis of 718 serum samples obtained from 3 different farms showed 91-59% prevalence to SwIAV, with 18-67% positivity to A(H1N1)pdm09-like strains and 29-58% positivity to a novel SwH1N2 virus. We also obtained a total of 1016 nasal swabs (NS, 85%) and 176 oral fluids (OF, 15%) that were tested by Real-time RT-PCR (qPCR) and virus isolation. Of these, 295 samples (25%) were positive to swIAV (23% of NS and 38% of OF). A large number of farms (21 out of 27, 78%) were positive in at least one visit, and most farms showed temporal co-circulation of at least 2 viruses or mixed infections. We subtyped selected positive samples and sequenced 51 complete viral genomes using the Illumina platform. Nineteen additional hemagglutinins (HA) genes were sequenced by Sanger. We performed Bayesian Evolutionary Analyses to reconstruct the phylogenies of the viral segments. This identified the circulation of 2 predominant swIAV genotypes in Chile, the A(H1N1)pdm09-like (35%) strain and a novel SwH1N2 virus (45%). This H1N2 virus is unique to Chile since it is genetically distinct from the H1 virus clusters seen in North America and is not related to any previously reported IAV. The genome of this swH1N1 virus contains genes from 3 different human contemporary viruses. Its H1 and N2 genes are derived from human H1N1 and H3N2 viruses from the mid 90’s, respectively, suggesting that both of these human viruses were likely introduced into the Chilean swine population during that time. All the internal genes are from the A(H1N1)pdm09 strain, indicating that multiple and recent reassortment events gave rise to this novel reassortant virus. Of interest, we identified additional reassortant viruses that also contain the internal genes derived from the A(H1N1)pdm09 strain. These included an H1N1 containing the novel SwH1 and NA gene derived from the A(H1N1)pdm09-like strain, an H1N2 virus containing an H1 derived from the A(H1N1)pdm09 strain and the novel SwN2, a SwH3N2 virus and a human-like H3N2 virus, among others. Additionally, our analyses also revealed at least 3 independent human-to-swine introductions of the A(H1N1)pdm09 strain within the last 4 years in Chile. Overall this indicates that close human-swine interactions greatly contribute to the genetic diversity and emergence of IAVs in Chilean swine. This is the first comprehensive molecular epidemiological study of swIAV in Chile demonstrating the co-circulation of multiple viral strains in intensive swine production systems. Our data emphasizes the value of conducting long-term SwIAV surveillance in Latin America, a poorly studied region of the world. Acknowledgements: CEIRS program: HHSN266200700010C, HHSN272201400008C from NIH-NIAID, FONDEF IDeA Grant ID14I10201 and Proyecto Anillo de Investigación en Ciencia y Tecnología - PIA ACT1408, both from CONICYT Chile

The AGASA/SUGAR Anisotropies and TeV Gamma Rays from the Galactic Center: A Possible Signature of Extremely High-energy Neutrons

Recent analysis of data sets from two extensive air shower cosmic ray detectors shows tantalizing evidence of an anisotropic overabundance of cosmic rays towards the Galactic Center (GC) that ``turns on'' around $10^{18}$ eV. We demonstrate that the anisotropy could be due to neutrons created at the Galactic Center through charge-exchange in proton-proton collisions, where the incident, high energy protons obey an $\sim E^{-2}$ power law associated with acceleration at a strong shock. We show that the normalization supplied by the gamma-ray signal from EGRET GC source 3EG J1746-2851 -- ascribed to pp induced neutral pion decay at GeV energies -- together with a very reasonable spectral index of 2.2, predicts a neutron flux at $\sim 10^{18}$ eV fully consistent with the extremely high energy cosmic ray data. Likewise, the normalization supplied by the very recent GC data from the HESS air-Cerenkov telescope at \~TeV energies is almost equally-well compatible with the $\sim 10^{18}$ eV cosmic ray data. Interestingly, however, the EGRET and HESS data appear to be themselves incompatible. We consider the implications of this discrepancy. We discuss why the Galactic Center environment can allow diffusive shock acceleration at strong shocks up to energies approaching the ankle in the cosmic ray spectrum. Finally, we argue that the shock acceleration may be occuring in the shell of Sagittarius A East, an unusual supernova remnant located very close to the Galactic Center. If this connection between the anisotropy and Sagittarius A East could be firmly established it would be the first direct evidence for a particular Galactic source of cosmic rays up to energies near the ankle.Comment: 57 pages, 2 figure

Arouca Geopark: Geotourists are arriving!

1 página.-- IES-04 Geoparks and geotourism.The present work is being performed under the project "Identification, Characterization and Conservation of Geological Heritage: a Geoconservation strategy for Portugal" sponsored by the Portuguese Foundation of Science and Technology (PTDC/CTE-GEX/64966/2006, years 2007-2009), and is also part of the PATRIORSI project of the Spanish Ministry of Education and Science (CGL2006-07628/BTE, years 2006-2009).Peer reviewe

Optimal Nitrogen Fertilization to Reach the Maximum Grain and Stover Yields of Maize (Zea mays L.): Tendency Modeling

Utilization of maize stover to the production of meat and milk and saving the grains for human consumption would be one strategy for the optimal usage of resources. Variance and tendency analyses were applied to find the optimal nitrogen (N) fertilization dose (0, 100, 145, 190, 240, and 290 kg/ha) for forage (F), stover (S), cob (C), and grain (G) yields, as well as the optimal grain-to-forage, cob-to-forage, and cob-to-stover ratios (G:F, C:F, and C:S, respectively). The study was performed in central Mexico (20.691389° N and −101.259722° W, 1740 m a.m.s.l.; Cwa (Köppen), 699 mm annual precipitation; alluvial soils). N-190 and N-240 improved the individual yields and ratios the most. Linear and quadratic models for CDM, GDM, and G:F ratio had coefficients of determination (R2) of 0.20–0.46 (p < 0.03). Cubic showed R2 = 0.30–0.72 (p < 0.02), and the best models were for CDM, GDM, and the G:F, C:F, and C:S DM ratios (R2 = 0.60–0.72; p < 0.0002). Neither SHB nor SDM negatively correlated with CDM or GDM (r = 0.23–0.48; p < 0.0001). Excess of N had negative effects on forage, stover, cobs, and grains yields, but optimal N fertilization increased the proportion of the G:F, C:F, and C:S ratios, as well as the SHB and SDM yields, without negative effects on grain production