84 research outputs found

    El linaje K´ulub cambia de estrategia. Diversificación productiva en la zona cafetalera de Oxchuc, Chiapas.

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     Se analiza un caso de innovación socioambiental exitosa en un contexto de deterioro generalizado de las condiciones de vida y de trabajo de los campesinos mexicanos. Se describe la lógica aplicada por los miembros del linaje K´ulub (Oxchuc, Chiapas), para lograr un cambio en su estrategia de vida. Se aplicó el método de estudios de caso para observar el comportamiento del linaje K´ulub durante el periodo 2007-2014. El marco de Medios de Vida permitió analizar el proceso de cambio de estrategia del linaje. El estudio de los ciclos de la política pública permitió comprender la forma en que el líder del linaje K´ulub interactúa con las dependencias gubernamentales. Los resultados muestran que el gestor del linaje (Wolwanej) participó en diversos talleres que le permitieron hacer el diagnóstico de su situación, buscar y elegir alternativas de solución deseables, movilizar sus propios recursos y gestionar los faltantes (principalmente capital físico y financiero), y ejecutar su idea de proyecto, con un éxito notable. Aunque en el proceso se involucraron varias dependencias y actores locales, el Wolwanej siempre mantuvo su autonomía. Se concluye que en las comunidades indígenas existen formas de organización y prácticas organizativas que permiten la introducción y persistencia de innovaciones socioambientales

    Edible films based on black chia (Salvia hispanica l.) seed mucilage containing Rhus microphylla fruit phenolic extract

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    Functional films based on black chia (Salvia hispanica L.) seed mucilage (BCm) containing Rhus microphylla (Rm) fruit phenolic extract were built and characterized. A hydro-alcohol extract (HAE) of Rm was incorporated as the bioactive agent due to its noteworthy phenolic profile, and good antioxidant and antifungal activities. The effects of the BCm concentration (0.2% and 0.4%, w/v), HAE incorporation, and their interaction with glycerol (1.0%, w/v) and calcium chloride (0.05%, w/v) on the films physicochemical properties were evaluated. The filmogenic solutions successfully fitted to the HerschelBulkley model (R2 0.05) changed by the HAE addition, but their surface tension was enhanced (p < 0.05), which could favor their coating ability. The polyanionic nature of the systems (zeta potential-Zp values from 26.9 to 33.3 mV) allowed them to interact with Ca2+ cations, thus forming stable and resistant films. All the films showed low water solubility (15.0% to 22.3%) and high permeability (3.7 to 4.0 × 1010 g m1 s1 Pa1), as well as high biodegradability (moisture content from 66.0% to 80.9%); although the moisture content was reduced (p < 0.05) with HAE addition. The combination of higher BCm ratio and HAE addition (BCm0.4+Rm) led to a more resistant, thick, opaque, and dark film compared with the others obtained. This study reveals the BCm-based films potential, highlighting those with HAE, representing a novel alternative to improve the quality of food products.Financial support from Universidad Autónoma Agraria Antonio Narro (UAAAN) is gratefully acknowledged by the authors. Zlatina Genisheva thanks to Foundation for Science and Technology (FCT) for the financial support (ref. SFRH/BPD/108868/2015) and to the project COMPETE 2020 (POCI-01-0145-FEDER-029145). This study was supported by FCT under the scope of the strategic funding of UIDB/04469/2020 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. The authors would also like to thank to Pablo Virgen of Biocampo S.A. de C.V. and MSc Fidel Peña-Ramos from UAAAN, for their assistance during this study.info:eu-repo/semantics/publishedVersio

    Tuning intermolecular charge transfer in donor-acceptor two-dimensional crystals on metal surfaces

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    Organic charge transfer (CT) compounds display a wide range of exotic electronic properties (charge-density wave stabilization, Peierls transitions, etc.) depending on the amount of charge transferred from the donor (D) to the acceptor (A) species. A complete exploration of the complex electronic phase diagrams for such compounds would thus require methods to systematically tune the amount of charge exchanged in the CT process. This has proven however challenging in the past: chemical functionalization of the constituent molecules can also affect the packing of the molecular units in the crystal, whereas changing D:A stoichiometry is often not possible in the bulk. Interestingly, it was recently found that multiple stoichiometries can actually be achieved by codeposition of different amounts of D and A molecules on metal surfaces. The question, however, of whether CT processes between D and A molecules can be tuned with the D:A ratio in such mixtures has not yet been studied, and it is no trivial matter, since competing CT processes between the metal surface and the organic adsorbates might hinder interadsorbate charge transfer. Here we demonstrate that the CT process from the organic donor tetrathiafulvalene (TTF) to the acceptor tetracyanoquino-p-dimethane (TCNQ) can be tuned with exquisite accuracy (∼0.1 e) by controlling the stoichiometry of D:A cocrystals deposited on Ag(111). This control opens new avenues to explore the complex phase diagrams of organic CT compounds and to tailor their electronic properties.The authors acknowledge financial support from the Spanish Ministry for Economy and Competitiveness (Grants FIS2012-33011, FIS2015-67367-C2-1-P, FIS2013-42002-R, FIS2016-77889-R, CTQ2013-43698-P, CTQ2016-76061-P), the regional government of Comunidad de Madrid (Grants S2009/MAT1726 and S2013/MIT-3007), Universidad Autónoma de Madrid (UAM/48) and IMDEA Nanoscience. L.F. acknowledges financial support from MIUR (PRIN-2010BNZ3F2, Project DESCARTES), S.D.-T. acknowledges the ‘“Ramón y Cajal”’ program of the MINECO (RYC-2010-07019), and the María de Maeztu Programme for Units of Excellence in R&D of the MINECO (MDM-2014-0377)

    Neuroprotective Natural Molecules, From Food to Brain

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    The prevalence of neurodegenerative disorders is increasing; however, an effective neuroprotective treatment is still remaining. Nutrition plays an important role in neuroprotection as recently shown by epidemiological and biochemical studies which identified food components as promising therapeutic agents. Neuroprotection includes mechanisms such as activation of specific receptors, changes in enzymatic neuronal activity, and synthesis and secretion of different bioactive molecules. All these mechanisms are focused on preventing neuronal damage and alleviating the consequences of massive cell loss. Some neuropathological disorders selectively affect to particular neuronal populations, thus is important to know their neurochemical and anatomical properties in order to design effective therapies. Although the design of such treatments would be specific to neuronal groups sensible to damage, the effect would have an impact in the whole nervous system. The difficult overcoming of the blood brain barrier has hampered the development of efficient therapies for prevention or protection. This structure is a physical, enzymatic, and influx barrier that efficiently protects the brain from exogenous molecules. Therefore, the development of new strategies, like nanocarriers, that help to promote the access of neuroprotective molecules to the brain, is needed for providing more effective therapies for the disorders of the central nervous system (CNS). In order both to trace the success of these nanoplatforms on the release of the bioactive cargo in the CNS and determinate the concentration at trace levels of targets biomolecules by analytical chemistry and concretely separation instrumental techniques, constitute an essential tool. Currently, these techniques are used for the determination and identification of natural neuroprotective molecules in complex matrixes at different concentration levels. Separation techniques such as chromatography and capillary electrophoresis (CE), using optical and/or mass spectrometry (MS) detectors, provide multiples combinations for the quantitative and qualitative analysis at basal levels or higher concentrations of bioactive analytes in biological samples. Bearing this in mind, the development of food neuroprotective molecules as brain therapeutic agents is a complex task that requires the intimate collaboration and engagement of different disciplines for a successful outcome. In this sense, this work reviews the new advances achieved in the area toward a better understanding of the current state of the art and highlights promising approaches for brain neuroprotection

    The Pierre Auger Observatory III: Other Astrophysical Observations

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    Astrophysical observations of ultra-high-energy cosmic rays with the Pierre Auger ObservatoryComment: Contributions to the 32nd International Cosmic Ray Conference, Beijing, China, August 201

    Operations of and Future Plans for the Pierre Auger Observatory

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    Technical reports on operations and features of the Pierre Auger Observatory, including ongoing and planned enhancements and the status of the future northern hemisphere portion of the Observatory. Contributions to the 31st International Cosmic Ray Conference, Lodz, Poland, July 2009.Comment: Contributions to the 31st ICRC, Lodz, Poland, July 200

    Measurement of the Depth of Maximum of Extensive Air Showers above 10^18 eV

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    We describe the measurement of the depth of maximum, Xmax, of the longitudinal development of air showers induced by cosmic rays. Almost four thousand events above 10^18 eV observed by the fluorescence detector of the Pierre Auger Observatory in coincidence with at least one surface detector station are selected for the analysis. The average shower maximum was found to evolve with energy at a rate of (106 +35/-21) g/cm^2/decade below 10^(18.24 +/- 0.05) eV and (24 +/- 3) g/cm^2/decade above this energy. The measured shower-to-shower fluctuations decrease from about 55 to 26 g/cm^2. The interpretation of these results in terms of the cosmic ray mass composition is briefly discussed.Comment: Accepted for publication by PR

    The exposure of the hybrid detector of the Pierre Auger Observatory

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    The Pierre Auger Observatory is a detector for ultra-high energy cosmic rays. It consists of a surface array to measure secondary particles at ground level and a fluorescence detector to measure the development of air showers in the atmosphere above the array. The "hybrid" detection mode combines the information from the two subsystems. We describe the determination of the hybrid exposure for events observed by the fluorescence telescopes in coincidence with at least one water-Cherenkov detector of the surface array. A detailed knowledge of the time dependence of the detection operations is crucial for an accurate evaluation of the exposure. We discuss the relevance of monitoring data collected during operations, such as the status of the fluorescence detector, background light and atmospheric conditions, that are used in both simulation and reconstruction.Comment: Paper accepted by Astroparticle Physic
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