1,111 research outputs found

    Coyuntura agraria y desigualdad en Guatemala, un contrato social postergado Agrarian conjuncture and inequality in Guatemala, a postponed social contract

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    La mirada de la larga duración ofrece la coherencia diacrónica para un análisis teórico de las continuidades agrarias de la realidad guatemalteca, desde una perspectiva metodológica inspirada en la ecología política. Se parte de los principios agrarios coloniales propuestos por Severo Martínez Peláez y de sus equivalentes contemporáneos, en una sociedad cuya estructura agraria presenta síntomas agudos de injusticia social, deterioro medioambiental y conflictividad rural. El acaparamiento de tierras en este contexto es un fenómeno arraigado que perpetúa las causas estructurales de la pobreza rural. Se evidencia, de hecho, una estructuración de lo agrario inspirada en un ethos señorial heredado de un pasado colonial y de las prácticas liberales puestas en marcha a finales del siglo XIX. Por otro lado, este trabajo rescata los instantes de humanidad benjamianos asociados a los esfuerzos contrahegemónicos encabezados por un sujeto colectivo en resistencia y, en definitiva, por una lógica coherente con una ética de la tierra. Finalmente, las continuidades identificadas se describen en el marco de una realidad contemporánea profundamente contradictoria, en la que asistimos a la disputa por el relato de un mundo agrario abocado al colapso de la agricultura campesina, como resultado de la reificación generalizada de la vida rural. Avances de este estudio fueron presentados como comunicación en el II Congreso Internacional: Transiciones en la Agricultura y la Sociedad Rural, Los desafíos globales de la Historia Rural, en junio de 2018 en la Universidad de Santiago de Compostela, Galicia, España

    A simple mathematical model that describes the growth of the area and the number of total and viable cells in yeast colonies

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    We propose a model, based on the Gompertz equation, to describe the growth of yeasts colonies on agar medium. This model presents several advantages: (i) one equation describes the colony growth, which previously needed two separate ones (linear increase of radius and of the squared radius); (ii) a similar equation can be applied to total and viable cells, colony area or colony radius, because the number of total cells in mature colonies is proportional to their area; and (iii) its parameters estimate the cell yield, the cell concentration that triggers growth limitation and the effect of this limitation on the specific growth rate. To elaborate the model, area, total and viable cells of 600 colonies of Saccharomyces cerevisiae, Debaryomyces fabryi, Zygosaccharomyces rouxii and Rhodotorula glutinis have been measured. With low inocula, viable cells showed an initial short exponential phase when colonies were not visible. This phase was shortened with higher inocula. In visible or mature colonies, cell growth displayed Gompertz-type kinetics. It was concluded that the cells growth in colonies is similar to liquid cultures only during the first hours, the rest of the time they grow, with near-zero specific growth rates, at least for 3 weeks

    5G Visualization: The METIS-II Project Approach

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    [EN] One of the main objectives of the METIS-II project was to enable 5G concepts to reach and convince a wide audience from technology experts to decision makers from non-ICT industries. To achieve this objective, it was necessary to provide easy-to-understand and insightful visualization of 5G. This paper presents the visualization platform developed in the METIS-II project as a joint work of researchers and artists, which is a 3D visualization tool that allows viewers to interact with 5G-enabled scenarios, while permitting simulation driven data to be intuitively evaluated. The platform is a game-based customizable tool that allows a rapid integration of new concepts, allows real-time interaction with remote 5G simulators, and provides a virtual reality-based immersive user experience. As a result, the METIS-II visualization platform has successfully contributed to the dissemination of 5G in different fora and its use will be continued after METIS-II.This work has been performed in the framework of the H2020/5G-PPP project METIS-II cofunded by the EU. The authors wish to thank the rest of METIS-II colleagues who contributed to the development of the METIS-II visualization platform.Martín-Sacristán, D.; Herranz Claveras, C.; Monserrat Del Río, JF.; Szczygiel, A.; Kuruvatti, NP.; Garcia-Roger, D.; Prado-Alvarez, D.... (2018). 5G Visualization: The METIS-II Project Approach. Mobile Information Systems. 1-8. https://doi.org/10.1155/2018/2084950S18Zyda, M. (2005). From visual simulation to virtual reality to games. Computer, 38(9), 25-32. doi:10.1109/mc.2005.297Johnson, C. (2004). Top scientific visualization research problems. IEEE Computer Graphics and Applications, 24(4), 13-17. doi:10.1109/mcg.2004.20Tullberg, H., Popovski, P., Li, Z., Uusitalo, M. A., Hoglund, A., Bulakci, O., … Monserrat, J. F. (2016). The METIS 5G System Concept: Meeting the 5G Requirements. IEEE Communications Magazine, 54(12), 132-139. doi:10.1109/mcom.2016.1500799cmLee, B., Riche, N. H., Isenberg, P., & Carpendale, S. (2015). More Than Telling a Story: Transforming Data into Visually Shared Stories. IEEE Computer Graphics and Applications, 35(5), 84-90. doi:10.1109/mcg.2015.99Yi, J. S., Kang, Y. ah, & Stasko, J. (2007). Toward a Deeper Understanding of the Role of Interaction in Information Visualization. IEEE Transactions on Visualization and Computer Graphics, 13(6), 1224-1231. doi:10.1109/tvcg.2007.70515Campbell, B. D. (2016). Immersive Visualization to Support Scientific Insight. IEEE Computer Graphics and Applications, 36(3), 17-21. doi:10.1109/mcg.2016.6

    Dark Matter and Higgs Sector

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    The inert doublet model is an extension of the Standard Model of Elementary Particles that is defined by the only addition of a second Higgs doublet without couplings to quarks or leptons. This minimal framework has been studied for many reasons. In particular, it has been suggested that the new degrees of freedom contained in this doublet can account for the Dark Matter of the Universe.Comment: 6 pages, 3 figures,To appear in the Proceedings of the sixth International Workshop on the Dark Side of the Universe (DSU2010) Leon, Guanajuato, Mexico 1-6 June 201

    Impact of perineural invasion on the outcome of patients with synchronous colorectal liver metastases treated with neoadjuvant chemotherapy and surgery

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    Purpose: To analyze the prognostic value of variables of the primary tumor in patients with synchronous liver metastases in colorectal cancer (CLRMs) treated with neoadjuvant chemotherapy and surgery. Methods/patients: From a prospective database, we retrospectively identified all patients with synchronous CLRMs who were treated with neoadjuvant chemotherapy and liver resection. Using univariate and multivariate analyses, we identified the variables associated with tumor recurrence. Overall survival and disease-free survival were calculated using the Kaplan-Meier method with differences determined by the Cox multiple hazards model. Results were compared using the log-rank test. Results: Ninety-eight patients with synchronous CLRMs were identified. With a median follow-up of 39.8 months, overall survival and disease-free survival at 5 and 10 years were 53%, 41.7%, 29% and 29%, respectively. Univariate analysis identified three variables associated with tumor recurrence: location in the colon (p = 0.025), lymphovascular invasion (p = 0.011) and perineural invasion (p = 0.005). Multivariate analysis identified two variables associated with worse overall survival: perineural invasion (HR 2.36, 95% CI 1.162-4.818, p = 0.018) and performing frontline colectomy (HR 3.286, 95% CI 1.256-8.597, p = 0.015). Perineural invasion remained as the only variable associated with lower disease-free survival (HR 1.867, 95% CI 1.013-3.441, p = 0.045). Overall survival at 5 and 10 years in patients with and without perineural invasion was 68.2%, 54.4% and 29.9% and 21.3%, respectively (HR 5.920, 95% CI 2.241-15.630, p < 0.001). Conclusions: Perineural invasion in the primary tumor is the variable with most impact on survival in patients with synchronous CLRMs treated with neoadjuvant chemotherapy and surgery

    Measurement Invariance of the Meaning in Life Questionnaire Across 17 Countries

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    The Meaning in Life Questionnaire assesses presence of and search for meaning in life. Although the questionnaire has shown promising psychometric properties in samples from different countries, the scale’s measurement invariance across a large number of nations has yet to be assessed. This study is aimed at addressing this gap, providing insight into how meaning in life is constructed and experienced across countries and into the extent to which cross-country comparisons can be made. A total of 3867 adult participants from 17 countries, aged 30–60, balanced by gender, and with at least secondary education, completed the questionnaire as part of the Eudaimonic and Hedonic Happiness Investigation. Single sample confirmatory factor analysis, multigroup confirmatory factor analysis, and alignment optimization were applied to investigate the scale’s performance across the samples. Good psychometric properties and high levels of approximate measurement invariance emerged for the Presence subscale after removal of item 9, the only reverse-phrased item. Performance of the Search subscale varied more across samples, suggesting caution in interpreting related results supporting approximate measurement invariance. The conceptualization of presence of meaning operationalized in the corresponding subscale (without item 9) appears consistent across countries, whereas search for meaning seems to be less universally homogenous and requires further exploration. Moreover, the Meaning in Life Questionnaire does not reflect the conceptual distinction between “purpose” and “meaning” currently acknowledged by researchers. This issue should be further explored in studies addressing the scale’s performance across cultures

    Towards an applied metaecology

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    The complexity of ecological systems is a major challenge for practitioners and decision-makers who work to avoid, mitigate and manage environmental change. Here, we illustrate how metaecology - the study of spatial interdependencies among ecological systems through fluxes of organisms, energy, and matter - can enhance understanding and improve managing environmental change at multiple spatial scales. We present several case studies illustrating how the framework has leveraged decision-making in conservation, restoration and risk management. Nevertheless, an explicit incorporation of metaecology is still uncommon in the applied ecology literature, and in action guidelines addressing environmental change. This is unfortunate because the many facets of environmental change can be framed as modifying spatial context, connectedness and dominant regulating processes - the defining features of metaecological systems. Narrowing the gap between theory and practice will require incorporating system-specific realism in otherwise predominantly conceptual studies, as well as deliberately studying scenarios of environmental change. (C) 2019 Associacao Brasileira de Ciencia Ecologica e Conservacao. Published by Elsevier Editora Ltda.Peer reviewe

    Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

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    The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

    Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

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    We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file
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