Modelo analítico para sistema de descarga de calor en techos

En el presente trabajo, se propone un modelo analítico que describe el comportamiento térmico de un sistema de descarga de calor en techo. Para validarlo, se empleó un prototipo experimental al cual se le realizó una prueba con exposición al sol y se comparó los resultados medidos con los calculados por un modelo analítico propuesto por lo autores. Se encontró variaciones de error entre los datos tomados en la prueba experimental y en el modelo analítico de 6.5 ºC como máximo para la placa de aluminio (o almacenadora de calor) y de 4.6 ºC como máximo para la temperatura en la superficie del vidrio. Se considera que el modelo analítico propuesto puede ser empleado para conocer el comportamiento de un sistema de descarga de calor en techos definiendo las dimensiones del sistema para las condiciones ambientales del lugar donde se va a utilizar.Fil: Hernández G., Víctor. Universidad Nacional Autónoma de México; MéxicoFil: Fernández Z., José. Universidad Nacional Autónoma de México; MéxicoFil: Morillón Galvez, David. Universidad Nacional Autónoma de México; MéxicoFil: Mesa, Nestor Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; Argentin

Broomrape (Orobanche Cumana Wallr.) resistance breeding utilizing wild Helianthus species

Wild Helianthus species possess valuable resistance genes for sunflower broomrape (Orobanche cumana Wallr.), especially the 39 largely underutilized perennial species. Resistance to race F has been transferred into a cultivated background via bridging of interspecific amphiploids. More recently, a single dominant gene resistant to race G was identified in annual H. debilis ssp. tardi-florus and transferred into cultivated HA 89. Interspecific crosses between wild annual Helianthus species and cultivated lines are relatively easy compared to those involving wild perennial species, which were made easier only after the development of embryo rescue techniques. Interspecific amphiploids resulting from colchicine treatment of F1 hybrids provide bridging materials for transferring genes without relying on embryo rescue. Among the diploid, tetraploid, and hexaploid perennial species, the speed of gene utilization follows the ploidy level of diploids, tetraploids, and hexaploids due to the time-consuming backcrosses required to eliminate the extra chromosomes in the latter two groups. In the development of pre-breeding materials, the retention rate of genetic material of the wild species is another concern with each additional backcross. For crosses involving tetraploid and hexaploid wild perennials, the use of 2n=51 chromosome F1 or BC1F1 generation, as pollen source, could accelerate chromosome reduction to 2n=34 in BC1F1 or BC2F1, resulting in useful materials with fewer backcrosses for trait selection.This work is partially funded by a National Sclerotinia Grant awarded to C.C. Jan.Peer Reviewe

Correlation between magnetic and transport properties in nanocrystalline Fe thin films: A grain-boundary magnetic disorder effect

We report on transport and magnetic measurements of islanded Fe(110) thin films. The electrical resistivity exhibits an anomalous increase at low temperatures, which disappears under the action of a magnetic field. Since such an anomaly completely disappears under the action of a magnetic field, it is inferred that it originates from spin-dependent scattering. We interpret the strong changes in the spin-dependent scattering in our films to be due to a low-temperature spin freezing of the island boundary magnetic regions that impedes ferromagnetic exchange between islands. A consequence of this magnetic behavior is the random arrangement of the individual magnetization, determined by the magnetocrystalline anisotropy of each island, resulting in an increase of the resistivity below the freezing temperature.Z.S. and J.L.M. acknowledge the Comunidad de Madrid for financial support. Work was performed under the financial support of the Comunidad de Madrid and the Spanish Commission of Science and Technology.Peer reviewe

Simulating Rainfall, Water Evaporation and Groundwater Flow in Three-Dimensional Satellite Images with Cellular Automata

Remote sensing has been used in numerous environmental simulations with the aim of solving and improving many different kinds of problems, e.g., meteorology applications, soil quality studies, water resource exploration, and environmental protection. Besides, cellular automata have been widely used in the field of remote sensing for simulating natural phenomena over two-dimensional satellite images. However, simulations on Digital Elevation Models (DEM), or three-dimensional (3D) satellite images, are scarce. This paper presents a study of modeling and simulation of the weather phenomena of rainfall, water evaporation and groundwater flow in 3D satellite images through a new algorithm, developed by the authors, named RACA (Rainfall with Cellular Automata). The purpose of RACA is to obtain, from the simulation, numerical and 3D results related to the total cumulative flow and maximum level of water that allow us to make decisions on important issues such as analyzing how climate change will affect the water level in a particular area, estimating the future water supply of a population, establishing future construction projects and urban planning away from locations with high probability of flooding, or preventing the destruction of property and human life from future natural disasters in urban areas with probability of flooding

TEMPORAL TRENDS OF HEAVY METAL CONCENTRATIONS IN BROWN MACROALGAE FROM COASTAL ENVIRONMENTS

Heavy metals are one of the major drivers of ecological changes in coastal ecosystems. Macroalgae are primary producers of great relevance for ecosystem structure and functioning in these environments, and play a key role in the trophic transfer of these contaminants in the food web. Here, we present the most extensive assessment until now (>3500 records) of heavy metal concentrations in brown macroalgae (Class Phaeophyceae) sampled between 1933 and 2020 worldwide. The study compiles this information from 420 peer reviewed articles to be used as a proxy of global long-term changes in metal concentrations. We report the first detailed multi-decadal time series of Cd, Co, Cr, Cu, Fe, Hg, Mn, Pb and Zn in algae using generalized additive models (GAMs), confirming a significant decrease in metal contamination in the world’s coastal environments since ca. the 1970s for Pb (84% reduction), Zn (79%), Cd (77%) and Cu (72%), since the 1980s for Mn (75%) and Hg (65%), and since the 1990s for Cr (66%), Fe (64%) and Co (60%). Important environmental consequences for the whole aquatic ecosystem, even for human health, may be expected from these changes. The present results provide a building block for the overall evaluation of the status and trends of marine metal contamination, and will help researchers and policy makers to promote new legal regulations and environmental goals against pollution

Reaction of the Halo Nucleus 11Be on Heavy Targets at Energies Around the Coulomb Barrier

New data for the reaction 11Be on 197Au at Elab=31.9 MeV are presented. The angular distributions of the inelastically scattered 11Be and the 10Be fragments coming from the 11Be dissociation have been extracted and compared with semiclassical and coupled-channels calculations in an angular range θlab=13∘–46∘ for the detected Be fragment.Ministerio de Ciencia e Innovación FPA2009-07387, FPA2009-07653, FPA2009-08848, FPA2012-32443 and CPAN CSD2007-00042Nuclear Astrophysics Virtual Institute (VH-VI-417

Scattering of the Halo Nucleus 11Be on 197Au at Energies around the Coulomb Barrier

Angular distributions of the elastic, inelastic, and breakup cross sections of the halo nucleus 11Be on197 Au were measured at energies below (Elab =31.9 MeV) and around (39.6 MeV) the Coulomb barrier. These three channels were unambiguously separated for the first time for reactions of 11Be on a high-Z target at low energies. The experiment was performed at TRIUMF (Vancouver, Canada). The differential cross sections were compared with three different calculations: semiclassical, inert-core continuum-coupled-channels and continuum-coupled-channels ones with including core deformation. These results show conclusively that the elastic and inelastic differential cross sections can only be accounted for if core-excited admixtures are taken into account. The cross sections for these channels strongly depend on the β (E1) distribution in 11Be, and the reaction mechanism is sensitive to the entanglement of core and halo degrees of freedom in 11Be.Ministerio de Economía y Competitividad FPA2015-64969-P, FIS2014-53448-C2-1-P, FPA2013-47327-c02-01-R, FPA2012-32443, FIS2013-41994-PCentro Nacional de Física de Partículas, Astropartículas y Nuclear CSD2007- 00042European Collaborative Research EUI-2009-04162European Unions 654002Nuclear Astrophysics Virtual Institute VH-VI-417European Commission, Seventh Framework Program 60037

Aerogel-based metasurfaces for perfect acoustic energy absorption

[EN] The unusual viscoelastic properties of silica aerogel plates are efficiently used to design subwavelength perfect sound absorbers. We theoretically, numerically and experimentally report a perfect absorbing metamaterial panel made of periodically arranged resonant building blocks consisting of a slit loaded by a clamped aerogel plate backed by a closed cavity. The impedance matching condition is analyzed using the Argand diagram of the reflection coefficient, i.e., the trajectory of the reflection coefficient as a function of frequency in the complex plane. The lack or excess of losses in the system can be identified via this Argrand diagram in order to achieve the impedance matching condition. The universality of this tool can be further exploited to design more complex metasurfaces for perfect sound absorption, thus allowing the rapid design of novel and efficient absorbing metamaterials.This work was funded by the RFI Le Mans Acoustique, Region Pays de la Loire. This article is based upon work from COST Action DENORMS CA15125, supported by COST (European Cooperation in Science and Technology). N.J. acknowledges financial support from Generalitat Valenciana through Grant No. APOSTD/2017/042. J.-P.G and V.R.G. gratefully acknowledge the ANR-RGC METARoom (No. ANR-18-CE08-0021) project and the HYPERMETA project funded under the program Etoiles Montantes of the Region Pays de la Loire. J.S-D. acknowledges the support of the Ministerio de Economia y Competitividad of the Spanish government and the European Union FEDER through Project No. TEC2014-53088-C3-1-RFernandez-Marin, AA.; Jimenez, N.; Groby, J.; Sánchez-Dehesa Moreno-Cid, J.; Romero García, V. (2019). Aerogel-based metasurfaces for perfect acoustic energy absorption. Applied Physics Letters. 115(6):061901-1-061901-5. https://doi.org/10.1063/1.5109084S061901-1061901-51156Gesser, H. D., & Goswami, P. C. (1989). Aerogels and related porous materials. Chemical Reviews, 89(4), 765-788. doi:10.1021/cr00094a003Herrmann, G., Iden, R., Mielke, M., Teich, F., & Ziegler, B. (1995). On the way to commercial production of silica aerogel. Journal of Non-Crystalline Solids, 186, 380-387. doi:10.1016/0022-3093(95)90076-4Fricke, J., Lu, X., Wang, P., Büttner, D., & Heinemann, U. (1992). Optimization of monolithic silica aerogel insulants. International Journal of Heat and Mass Transfer, 35(9), 2305-2309. doi:10.1016/0017-9310(92)90073-2Gerlach, R., Kraus, O., Fricke, J., Eccardt, P.-C., Kroemer, N., & Magori, V. (1992). Modified SiO2 aerogels as acoustic impedance matching layers in ultrasonic devices. Journal of Non-Crystalline Solids, 145, 227-232. doi:10.1016/s0022-3093(05)80461-2Gibiat, V., Lefeuvre, O., Woignier, T., Pelous, J., & Phalippou, J. (1995). Acoustic properties and potential applications of silica aerogels. Journal of Non-Crystalline Solids, 186, 244-255. doi:10.1016/0022-3093(95)00049-6Ma, G., Yang, M., Xiao, S., Yang, Z., & Sheng, P. (2014). Acoustic metasurface with hybrid resonances. Nature Materials, 13(9), 873-878. doi:10.1038/nmat3994Yang, M., Meng, C., Fu, C., Li, Y., Yang, Z., & Sheng, P. (2015). Subwavelength total acoustic absorption with degenerate resonators. Applied Physics Letters, 107(10), 104104. doi:10.1063/1.4930944Romero-García, V., Theocharis, G., Richoux, O., Merkel, A., Tournat, V., & Pagneux, V. (2016). Perfect and broadband acoustic absorption by critically coupled sub-wavelength resonators. Scientific Reports, 6(1). doi:10.1038/srep19519Li, Y., & Assouar, B. M. (2016). Acoustic metasurface-based perfect absorber with deep subwavelength thickness. Applied Physics Letters, 108(6), 063502. doi:10.1063/1.4941338Jiménez, N., Huang, W., Romero-García, V., Pagneux, V., & Groby, J.-P. (2016). Ultra-thin metamaterial for perfect and quasi-omnidirectional sound absorption. Applied Physics Letters, 109(12), 121902. doi:10.1063/1.4962328Peng, X., Ji, J., & Jing, Y. (2018). Composite honeycomb metasurface panel for broadband sound absorption. The Journal of the Acoustical Society of America, 144(4), EL255-EL261. doi:10.1121/1.5055847Yang, M., Ma, G., Yang, Z., & Sheng, P. (2013). Coupled Membranes with Doubly Negative Mass Density and Bulk Modulus. Physical Review Letters, 110(13). doi:10.1103/physrevlett.110.134301Yang, Z., Mei, J., Yang, M., Chan, N. H., & Sheng, P. (2008). Membrane-Type Acoustic Metamaterial with Negative Dynamic Mass. Physical Review Letters, 101(20). doi:10.1103/physrevlett.101.204301Lee, S. H., Park, C. M., Seo, Y. M., Wang, Z. G., & Kim, C. K. (2010). Composite Acoustic Medium with Simultaneously Negative Density and Modulus. Physical Review Letters, 104(5). doi:10.1103/physrevlett.104.054301Zhang, J., Romero-García, V., Theocharis, G., Richoux, O., Achilleos, V., & Frantzeskakis, D. (2016). Second-Harmonic Generation in Membrane-Type Nonlinear Acoustic Metamaterials. Crystals, 6(8), 86. doi:10.3390/cryst6080086Zhang, J., Romero-García, V., Theocharis, G., Richoux, O., Achilleos, V., & Frantzeskakis, D. J. (2017). Bright and gap solitons in membrane-type acoustic metamaterials. Physical Review E, 96(2). doi:10.1103/physreve.96.022214Stinson, M. R. (1991). The propagation of plane sound waves in narrow and wide circular tubes, and generalization to uniform tubes of arbitrary cross‐sectional shape. The Journal of the Acoustical Society of America, 89(2), 550-558. doi:10.1121/1.400379Kergomard, J., & Garcia, A. (1987). Simple discontinuities in acoustic waveguides at low frequencies: Critical analysis and formulae. Journal of Sound and Vibration, 114(3), 465-479. doi:10.1016/s0022-460x(87)80017-2M. J. Powell , in Numerical Analysis ( Springer, 1978) pp. 144–157.Groby, J.-P., Huang, W., Lardeau, A., & Aurégan, Y. (2015). The use of slow waves to design simple sound absorbing materials. Journal of Applied Physics, 117(12), 124903. doi:10.1063/1.4915115Jiménez, N., Groby, J.-P., Pagneux, V., & Romero-García, V. (2017). Iridescent Perfect Absorption in Critically-Coupled Acoustic Metamaterials Using the Transfer Matrix Method. Applied Sciences, 7(6), 618. doi:10.3390/app706061

Platelet count and Interleukin 6 Gene polymorphism in healthy subjects

BACKGROUND: Interleukin 6 (IL-6) is thought to play important roles in the development of reactive thrombocytosis caused by inflammation by its stimulatory effect on megakaryocytopoiesis. A G/C polymorphism of the IL-6 gene at position -174 has been found to be associated to different transcription rates. Specifically, subjects with the CC genotype showed lower plasma IL-6 levels compared with GC or GG subjects. Given this difference in transcription rates of IL-6 we speculated on different platelet count according to this IL-6 polymorphism. METHODS: The G/C polymorphism of the IL-6 gene at position -174, serum IL-6 concentration and platelet count were prospectively analyzed in 59 (25 women) consecutive healthy subjects. RESULTS: Subjects who were homozygotes for the C allele at position -174 of the IL-6 gene (Sfa NI genotype) showed significantly lower platelet count than carriers of the G allele, despite similar age, sex, body mass index and proportion of smokers (205400 ± 44088 vs 239818 ± 60194, p = 0.047). This was in parallel to differences in peripheral white blood cell count (5807 ± 1671 vs 6867 ± 1192 × 10(9)/ml, p = 0.01). CONCLUSION: This is the first description, to our knowledge, of a genetical influence on basal platelet counts, which appears to be partially dependent on a polymorphism of the IL-6 gene, even in the absence of inflammation

First experiment: Fragmentation of ions relevant for space and therapy

Nuclear fragmentation processes are relevant in different fields of basic research and applied physics and are of particular interest for tumor therapy and for space radiation protection applications. The FIRST (Fragmentation of Ions Relevant for Space and Therapy) experiment at SIS accelerator of GSI laboratory in Darmstadt, has been designed for the measurement of different ions fragmentation cross sections at different energies between 100 and 1000 MeV/nucleon. The experiment is performed by an international collaboration made of institutions from Germany, France, Italy and Spain. The experimental apparatus is partly based on an already existing setup made of the ALADIN magnet, the MUSIC IV TPC, the LAND2 neutron detector and the TOFWALL scintillator TOF system, integrated with newly designed detectors in the interaction Region (IR) around the carbon removable target: a scintillator Start Counter, a Beam Monitor drift chamber, a silicon Vertex Detector and a Proton Tagger for detection of light fragments emitted at large angles (KENTROS). The scientific program of the FIRST experiment started on summer 2011 with the study of the 400 MeV/nucleon 12C beam fragmentation on thin (8mm) carbon target