Evaluación experimental de un concentrador parabólico compuesto para aplicaciones de baja y mediana temperatura

Se presenta la evaluación de un concentrador parabólico compuesto (CPC) diseñado y construido en el Centro de Investigación en Energía de la Universidad Nacional Autónoma de México. El CPC tiene un área de apertura de 1.33 m2, una concentración real de 3.5 y ángulo medio de aceptación de 15°. Se utilizó un tubo receptor de acero al carbón con diámetro externo de 0.06 m cubierto con una superficie selectiva. En los resultados experimentales se presenta el incremento de temperatura, la curva de rendimiento térmico y la caída de presión que fueron obtenidos y comparados con un modelo numérico desarrollado. Los resultados experimentales del CPC muestran que puede aprovecharse en diversas aplicaciones que trabajen en rangos de baja y mediana temperatura con un buen desempeño térmico.An evaluation of a compound parabolic concentrator (CPC) designed and built at the Centro de Investigación en Energía of the Universidad Nacional Autónoma de México is presented. The CPC has an aperture area of 1.33 m2, a real concentration of 3.5 and acceptance half angle of 15 °. Tubular receiver with an outer diameter of 0.06 m and coated with a selective surface was used. In the experimental results the increment of temperature, the thermal performance curve and pressure drop were obtained and compared with a numerical simulation model developed. The experimental results of the CPC shows that it can be used in various applications that work in low and middle ranges of temperature with good thermal performance.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Modelación y simulación en TRNSYS de un concentrador solar cilíndrico parabólico a partir de datos experimentales

En este trabajo se presenta la modelación dinámica de un concentrador solar cilíndrico parabólico (CCP), con un área de apertura de 1.184 m2 y un factor de concentración de 23.73, construido en la Universidad del Istmo Campus Tehuantepec en función de datos experimentales. La geometría del colector solar, las propiedades físicas, ópticas de la superficie reflectora y del absorbedor así como los datos meteorológicos fueron utilizados para modelar en TRNSYS, se simularon dinámicamente los datos teóricos para hacer la comparación contra los datos experimentales y comprobar que el modelo fue adecuado. El objetivo principal fue el de poder extrapolar de un solo flujo al que fueron recabados los datos de operación del CCP a diferentes flujos con el modelo obtenido, así como estudiar una posible aplicación en un sistema de calentamiento solar para futuros trabajos

Evaluación experimental de un concentrador parabólico compuesto para aplicaciones de baja y mediana temperatura

Se presenta la evaluación de un concentrador parabólico compuesto (CPC) diseñado y construido en el Centro de Investigación en Energía de la Universidad Nacional Autónoma de México. El CPC tiene un área de apertura de 1.33 m2, una concentración real de 3.5 y ángulo medio de aceptación de 15°. Se utilizó un tubo receptor de acero al carbón con diámetro externo de 0.06 m cubierto con una superficie selectiva. En los resultados experimentales se presenta el incremento de temperatura, la curva de rendimiento térmico y la caída de presión que fueron obtenidos y comparados con un modelo numérico desarrollado. Los resultados experimentales del CPC muestran que puede aprovecharse en diversas aplicaciones que trabajen en rangos de baja y mediana temperatura con un buen desempeño térmico.An evaluation of a compound parabolic concentrator (CPC) designed and built at the Centro de Investigación en Energía of the Universidad Nacional Autónoma de México is presented. The CPC has an aperture area of 1.33 m2, a real concentration of 3.5 and acceptance half angle of 15 °. Tubular receiver with an outer diameter of 0.06 m and coated with a selective surface was used. In the experimental results the increment of temperature, the thermal performance curve and pressure drop were obtained and compared with a numerical simulation model developed. The experimental results of the CPC shows that it can be used in various applications that work in low and middle ranges of temperature with good thermal performance.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

ANTIMICROBIAL ACTIVITY OF MEDICINAL PLANTS FROM THE HUAUTLA SIERRA BIOSPHERE RESERVE IN MORELOS (MÉXICO)

Twenty-two extracts from nine Mexicanmedicinal plants of eight different familiesused for people neighbor to Huautla SierraBiosphere Reserve (REBIOSH) in differentinfectious diseases were assayed in vitro todetermine their antibacterial activity againstStaphylococcus aureus, Streptococcus faecalis; Escherichia coli; Proteus mirabilis;Salmonella typhi and the yeast Candidaalbicans. Most plants showed antibacterialactivity, while two plants showed activityagainst range 0.25 a 4 mg/mL almost onemicroorganism used. The extracts showedminimum inhibitory concentration (MIC)against S. aureus and S. faecalis, representsmicroorganisms Gram-positive were hexanic and acetonic extracts of Bursera copallifera and hexanic extract of B. grandifolia.The ethanol extract of Lippia graveolensshowed a MIC value of 1 mg/mL againstyeast Candida albicans.Se determinó la actividad antimicrobianade veintidós extractos orgánicos de nueveespecies vegetales medicinales de ochodiferentes familias, que son comúnmenteempleadas por los habitantes de las comunidades vecinas a la reserva de la biosferaSierra de Huautla (REBIOSH), Morelos,para tratar diferentes padecimientos infecciosos. Los microorganismos empleadosfueron: Staphylococcus aureus; Streptococcus faecalis; Escherichia coli; Proteusmirabilis; Salmonella typhi y la levaduraCandida albicans. La mayoría de los extractos de las plantas probadas inhibieronel crecimiento microbiano en un rango de0.25 a 4 mg/mL de al menos uno de losmicroorganismos utilizados. Los extractosque mostraron las menores concentracionesmínimas inhibitorias (CMI) frente a losmicroorganismos S. aureus y S. faecalis,representativos de Gram-positivos fueron el extracto hexánico y acetónico de Burseracopallifera y el hexánico de B. grandifolia.El extracto etanólico de Lippia graveolenslogró inhibir a C. albicans con una CMIde 1 mg/mL

Stress related epigenetic changes may explain opportunistic success in biological invasions in Antipode mussels

Different environmental factors could induce epigenetic changes, which are likely involved in the biological invasion process. Some of these factors are driven by humans as, for example, the pollution and deliberate or accidental introductions and others are due to natural conditions such as salinity. In this study, we have analysed the relationship between different stress factors: time in the new location, pollution and salinity with the methylation changes that could be involved in the invasive species tolerance to new environments. For this purpose, we have analysed two different mussels’ species, reciprocally introduced in antipode areas: the Mediterranean blue mussel Mytilus galloprovincialis and the New Zealand pygmy mussel Xenostrobus securis, widely recognized invaders outside their native distribution ranges. The demetylathion was higher in more stressed population, supporting the idea of epigenetic is involved in plasticity process. These results can open a new management protocols, using the epigenetic signals as potential pollution monitoring tool. We could use these epigenetic marks to recognise the invasive status in a population and determine potential biopollutants

Electrodepósito de níquel negro sobre aletas de cobre para aplicaciones en colectores solares planos

CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia SolarRESUMEN: En este trabajo se reporta el desempeño de colectores solares construidos con aletas de cobre recubiertas con níquel/níquel negro con y sin SiO2. Los recubrimientos de níquel y níquel negro fueron obtenidos mediante electrodepósito y la capa de SiO2 por sol-gel y roció pirolítico, los resultados se comparan con un colector construido con un recubrimiento selectivo comercial TiNOX. Los resultados muestran que el níquel negro con SiO2 tiene una curva de desempeño cercana al colector construidos con el recubrimiento comercial. El recubrimiento de níquel negro con SiO2 fue obtenido por técnicas de bajo costo lo cual pudiera ser atractivo para las empresas dedicadas a la construcción de colectores solares.ABSTRACT: This work reports the performance of solar collectors built with nickel / black nickel coated copper fins with and without SiO2. The nickel and black nickel coatings were obtained by electrodeposition, the SiO2 layer by sol-gel and spray pyrolysis methods, the results are compared with a collector built with a commercial selective coating TiNOX. The results show that black nickel with SiO2 have a near performance curve than the collector built with the commercial coating. The black nickel coating with SiO2 was obtained by low cost techniques which could be attractive for companies dedicated to the construction of solar collectors.info:eu-repo/semantics/publishedVersio

Natural selection on cork oak: allele frequency reveals divergent selection in cork oak populations along a temperature cline

A recent study of population divergence at neutral markers and adaptive traits in cork oak has observed an association between genetic distances at locus QpZAG46 and genetic distances for leaf size and growth. In that study it was proposed that certain loci could be linked to genes encoding for adaptive traits in cork oak and, thus, could be used in adaptation studies. In order to investigate this hypothesis, here we (1) looked for associations between molecular markers and a set of adaptive traits in cork oak, and (2) explored the effects of the climate on among-population patterns in adaptive traits and molecular markers. For this purpose, we chose 9-year-old plants originating from thirteen populations spanning a broad range of climatic conditions. Plants established in a common garden site were genotyped at six nuclear microsatellites and phenotypically characterized for six functional traits potentially related to plant performance. Our results supported the proposed linkage between locus QpZAG46 and genes encoding for leaf size and growth. Temperature caused adaptive population divergence in leaf size and growth, which was expressed as differences in the frequencies of the alleles at locus QpZAG46

Response of the photosynthetic apparatus to a flowering-inductive period by water stress in Citrus

The photosynthetic responses to a flowering-inductive water-stress period and recovery were studied and compared in two Citrus species. Under greenhouse conditions, Fino lemon and Owari satsuma trees were subjected to moderate (-2 MPa at predawn) and severe (-3 MPa) water stress levels and were re-watered after 60 days. Vegetative growth was inhibited during the stress assays, and strong defoliation levels were reported, especially in Fino lemon. In both species, bud sprouting was induced after re-watering. Flowers and vegetative shoots developed in Owari satsuma after a drought period, and the development was independent of the stress level. In Fino lemon, vegetative shoots and flowers were primarily formed after moderate and severe stress, respectively. The photosynthetic rate and stomatal conductance were reduced by water stress, and a marked increase in water-use efficiency at the moderate water deficit level was observed. Nevertheless, the photosynthetic apparatus was not damaged, since the maximum quantum yield, photosynthetic pigment concentrations and Rubisco level and activity did not change. Furthermore, the measured malonyldialdehyde (MDA) and peroxidase activity indicated that oxidative stress was not specifically triggered by water stress in our study. Therefore, the gas exchange, fluorescence and biochemical parameters suggested that diffusional limitations to photosynthesis predominated in both of the studied Citrus species, and explained the rapid recovery of the photosynthetic parameters after rehydration. The net CO 2 fixation rate and stomatal conductance were recovered within 24 h in Fino lemon, whereas 3 days were required in Owari satsuma. This suggests the presence of some metabolic limitations in the latter species. Furthermore, the sensibility of the defoliation rates, the accumulation of proline and the stomatal behaviour in response to water stress indicated a higher drought tolerance of Fino lemon, according to its better acclimation to hot climates. © 2011 Springer-Verlag.The authors thank Dr. J. Moreno and co-workers from the Departamento de Bioquimica of the Universidad de Valencia for his help and support in the Rubisco assays, and Dr. F. Fornes, Dr. A. Calatayud and Dr. E. Primo-Millo for the critical review of the manuscript. This work was funded by the Universitat Politecnica de Valencia, Spain (Ayudas para primeros proyectos de investigacion PAID06-06).Ávila Reséndiz, C.; Guardiola Barcena, JL.; González Nebauer, S. (2012). Response of the photosynthetic apparatus to a flowering-inductive period by water stress in Citrus. Trees - Structure and Function. 26(3):833-840. https://doi.org/10.1007/s00468-011-0657-4S833840263Addicott FT (1982) Abscission. University of California Press, BerkeleyBajji M, Kinet JM, Lutts S (1998) Salt stress effects on roots and leaves of Atriplex halimus L. and their corresponding callus. Plant Sci 137:131–142Barbera G, Fatta-del-Bosco G, Lo-Cascio B (1985) Effect of water stress on lemon summer bloom: the Forzatura technique in the Sicilian citrus industry. Acta Hortic 171:391–397Bates LS, Waldren RP, Teare ID (1973) Rapid determination of free proline for water stress studies. Plant Soil 39:205–207Bota J, Medrano H, Flexas J (2004) Is photosynthesis limited by decreased Rubisco activity and RuBP content under progressive water stress? New Phytol 162:671–681Bradford MM (1976) A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem 72:248–254Cassin J, Bourdeaut A, Fougue V, Furon V, Gaillard JP, LeBourdelles J, Montagut G, Moreuil C (1969) The influence of climate upon blooming of Citrus in tropical areas. Proc Int Soc Citrus 1:315–323Castel JR, Buj A (1990) Response of Salustiana oranges to high frequency deficit irrigation. Irrig Sci 11:121–127Chaikiatitiyos S, Menzel CM, Rasmussen TS (1994) Floral induction in tropical fruit trees: effects of temperature and water supply. J Hortic Sci 69:397–415Chaves MM, Flexas J, Pinheiro C (2009) Photosynthesis under drought and salt stress: regulation mechanisms from whole plant to cell. Ann Bot 103:551–560Costa JM, Ortuño MF, Chaves M (2007) Deficit irrigation as a strategy to save water: physiology and potential application to horticulture. J Integr Plant Biol 49:1421–1434Davenport TL (1990) Citrus flowering. Hortic Rev 12:249–408Davies FS, Albrigo LG (1994) Citrus. CAB International, Wallingford, pp 126–134Domingo R, Ruiz-Sánchez MC, Sánchez-Blanco MJ, Torrecillas A (1996) Water relations, growth and yield of Fino lemon trees under regulated deficit irrigation. Irrig Sci 16:115–123Erismann ND, Machado EC, Tucci MLS (2008) Photosynthetic limitation by CO2 diffusion in drought stressed orange leaves on three rootstocks. Photosynth Res 96:163–172Flexas J, Bota J, Galmés J, Medrano H, Ribas-Carbó M (2006) Keeping a positive carbon balance under adverse conditions: responses of photosynthesis and respiration to water stress. Physiol Plant 127:343–352Gallé A, Florez-Sarasa I, Tomas M, Pou A, Medrano H, Ribas-Carbó M, Flexas J (2009) The role of mesophyll conductance during water stress and recovery in tobacco (Nicotiana sylvestris): acclimation or limitation? J Exp Bot 60:2379–2390Galmés J, Medrano H, Flexas J (2007) Photosynthetic limitations in response to water stress and recovery in Mediterrenean plants with different growth forms. New Phytol 175:81–93García-Luis A, Kanduser M, Santamarina P, Guardiola JL (1992) Low temperature influence on flowering in Citrus. The separation of inductive and bud dormancy releasing effects. Physiol Plant 86:648–652García-Sánchez F, Syvertsen JP, Gimeno V, Botía P, Pérez-Pérez JG (2007) Responses to flooding and drought stress by two citrus rootstock seedlings with different water-use efficiency. Physiol Plant 130:532–542Genty B, Briantais JM, Baker NR (1989) The relationship between quantum yield of photosynthetic electron transport and quenching of chlorophyll fluorescence. Biochim Biophys Acta 990:87–92Gómez-Cadenas A, Tadeo FR, Talon M, Primo-Millo E (1996) Leaf abscission induced by ethylene in water-stressed intact seedlings of Cleopatra mandarin requires previous abscisic acid accumulation in roots. Plant Physiol 112:401–408Gordo O, Sanz JJ (2010) Impact of climate change on plant phenology in Mediterranean ecosystems. Glob Chang Biol 16:1082–1106Heath RL, Packer L (1968) Photoperoxidation in isolated chloroplasts. I. Kinetics and stoichiometry of fatty acid peroxidation. Arch Biochem Biophys 125:189–190Hoagland DR, Arnon DI (1950) The water culture method for growing plants without soil. California Agricultural Experiment Station Circular no. 347, p 32IPCC (2001) Climate change 2001. In: Houghton JT (ed) The scientific basis. Cambridge University Press, CambridgeLawlor DW (1995) The effects of water deficit on photosynthesis. In: Smirnoff N (ed) Environment and plant metabolism. Bios Scientific Publishers, Oxford, pp 129–160Lichtenthaler HK, Buschmann C (2001) Current protocols in food analytical chemistry, F4.2.1 and F4.3.1. John Wiley and Sons, Inc, NJLorimer GH, Badger MR, Andrews TJ (1977) D-Ribulose-1, 5-bisphosphate carboxilase-oxigenase. Improved methods for activation and assay of catalytic activities. Anal Biochem 78:66–75Miyashita K, Tanakamaru S, Maitani T, Kimura K (2005) Recovery responses of photosynthesis, transpiration, and stomatal conductance in kidney bean following drought stress. Environ Exp Bot 53:205–214Nir I, Leshem B, Goren R (1972) Effects of water stress, gibberellic acid and 2-chloroethylammoniumchloride (CCC) ob flower differentiation in Eureka lemon trees. J Am Soc Hortic Sci 97:774–778Peñarrubia L, Moreno J (1988) Ribulose 1, 5-bisphosphate carboxylase oxygenase from citrus leaves. Phytochemistry 27:1999–2004Pérez-Pérez JG, Syvertsen JP, Botía P, García-Sánchez F (2007) Leaf water relations and net gas exchange responses of salinized carrizo citrange seedlings during drought stress and recovery. Ann Bot 100:335–345Pérez-Pérez JG, Robles JM, Tovar JC, Botía P (2009) Response to drought and salt stress of lemon ‘Fino 49’ under field conditions: water relations, osmotic adjustment and gas Exchange. Sci Hortic 122:83–90Reynolds M, Tuberosa R (2008) Translational research impacting on crop productivity in drought-prone environments. Curr Opin Plant Biol 11:171–179Ruiz-Sánchez MC, Domingo R, Savé R, Biel C, Torrecillas A (1997) Effects of water stress and rewatering on leaf water relations of lemon plants. Biol Plant 39:623–631Sarris D, Christodoulakis D, Körner C (2007) Recent decline in precipitation and tree growth in the eastern Mediterranean. Glob Chang Biol 13:1187–1200Sharkey TD (1990) Water-stress effects on photosynthesis. Photosynthetica 24:651Southwick SM, Davenport TL (1986) Characterization of water stress and low temperature effects on flower induction in Citrus. Plant Physiol 81:26–29Spiegel-Roy P, Goldschmidt EE (1996) Biology of Citrus. Cambridge University Press, Cambridge, pp 131–136Syvertsen JP, Lloyd J (1994) Citrus. In: Schaffer BA, Andersen PC (eds) Handbook of environmental physiology of fruit crops. Vol II Subtropical and tropical crops. CRC Press, Boca Raton, pp 65–99Syvertsen JP (1996) Water stress and carbon budgets. Proc Int Soc Citrus 1:46–50Valladares F, Arrieta S, Aranda I, Lorenzo D, Sánchez-Gómez D, Tena D, Suarez F, Pardos JA (2005) Shade tolerance, photoinhibition sensitivity and phenotypic plasticity of Illex aquifolium in continental Mediterranean sites. Tree Physiol 25:1041–1052Vu JCV, Yelenosky G (1988) Solar irradiance and drought stress effects on the activity and concentration of ribulose bisphosphate carboxylase in ‘Valencia’ orange leaves. Isr J Bot 37:245–25

‘No hay más que un mundo’: Globalización y conexiones en los territorios ultramarinos de los Hasburgos españoles (1581-1640)

The study of the overseas empire of the Spanish Habsburgs during the period when the Crown of Portugal was incorporated to this politico-economic structure and the study of their encounters, exchanges and contributions at all levels are increasingly being perceived as a plausible and original alternative within the current historiographical debate evolving around the configuration of the new European political order produced during the Early Modern period and characterised by the so-called ‘crisis of the State’ and the economic ‘decadence’ of the territories of southern Europe. This article offers some observations concerning this interesting subject, as well as some insight into the implications that this process carried in the Spanish and Portuguese cases.Dentro del vigente debate historiográfico sobre la configuración del orden político europeo que se produjo durante la Edad Moderna, caracterizado por la llamada “crisis del Estado” y por la “decadencia” económica en los territorios del sur de Europa, el estudio de las posesiones de Ultramar de los Habsburgo españoles durante el momento de agregación de la Corona de Portugal a la Monarquía Hispánica (1581-1640), con sus encuentros, sus intercambios y sus mixturas a todos los niveles, se insinúa como una posible y original alternativa de trabajo y reflexión. En el presente artículo se ofrecen algunas consideraciones sobre esta interesante cuestión, destacando además las implicaciones que dicho proceso tuvo en los casos español y portugués

New insights into the genetic etiology of Alzheimer's disease and related dementias.

Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele