A C++11 implementation of arbitrary-rank tensors for high-performance computing

This article discusses an efficient implementation of tensors of arbitrary rank by using some of the idioms introduced by the recently published C++ ISO Standard (C++11). With the aims at providing a basic building block for high-performance computing, a single Array class template is carefully crafted, from which vectors, matrices, and even higher-order tensors can be created. An expression template facility is also built around the array class template to provide convenient mathematical syntax. As a result, by using templates, an extra high-level layer is added to the C++ language when dealing with algebraic objects and their operations, without compromising performance. The implementation is tested running on both CPU and GPU.Comment: 21 pages, 6 figures, 1 tabl

A machine learning approach for fighting the curse of dimensionality in global optimization

Finding global optima in high-dimensional optimization problems is extremely challenging since the number of function evaluations required to sufficiently explore the search space increases exponentially with its dimensionality. Furthermore, multimodal cost functions render local gradient-based search techniques ineffective. To overcome these difficulties, we propose to trim uninteresting regions of the search space where global optima are unlikely to be found by means of autoencoders, exploiting the lower intrinsic dimensionality of certain cost functions; optima are then searched over lower-dimensional latent spaces. The methodology is tested on benchmark functions and on multiple variations of a structural topology optimization problem, where we show that we can estimate this intrinsic lower dimensionality and based thereon obtain the global optimum at best or superior results compared to established optimization procedures at worst.Comment: Main text 36 pages, 6 figures, currently submitted to science advance

Imperfect Vertical Transmission of the Endophyte Neotyphodium in Exotic Grasses in Grasslands of the Flooding Pampa

Fil: Gundel, Pedro E. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas vinculadas a la Agricultura; Argentina.Fil: Garibaldi, Lucas Alejandro. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio Ecotono; Argentina.Fil: Tognetti, Pedro M. Universidad de Buenos Aires (UBA). Facultad de Agronomía; Argentina.Fil: Aragón, Roxana. Universidad de Buenos Aires (UBA). Facultad de Agronomía; Argentina.Fil: Ghersa, Claudio M. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas vinculadas a la Agricultura; Argentina.Fil: Omacini, Marina. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas vinculadas a la Agricultura; Argentina.Fil: Gundel, Pedro E. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Argentina.Fil: Garibaldi, Lucas Alejandro. Universidad de Buenos Aires (UBA). Facultad de Agronomía; Argentina.Fil: Ghersa, Claudio M. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Argentina.Fil: Omacini, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Argentina.Cool-season grasses establish symbioses with vertically transmitted Neotyphodium endophytes widespread in nature. The frequency of endophyte-infected plants in closed populations (i.e., without migrations) depends on both the differential fitness between infected and non-infected plants, and the endophyte-transmission efficiency. Most studies have been focused on the first mechanism ignoring the second. Infection frequency and endophyte transmission from vegetative tissues to seeds were surveyed in two grasses growing in vegetation units that differ in flood and grazing regimes, and soil salinity. Transmission efficiency and infection frequency for tall fescue did not vary significantly and were 0.98 and 1.00, respectively. For Italian ryegrass, transmission efficiency and infection frequency were 0.88 and 0.57 in humid prairies, and 0.96 and 0.96 in the other vegetation units. Only in humid mesophytic meadows, the observed pattern was irrespective of the presence or absence of grazers. Our results suggest that selection forces for endophyte infection are different for both species. Imperfect transmission was only compensated in tall fescue through an increased fitness of infected plants. Interpreting variations of infection frequency only in terms of differential fitness can be misleading, considering that endophyte transmission can be imperfect and variable in nature. Therefore, this study highlights the importance of measuring transmission efficiency

A 3-D indoor analysis of path loss modeling using kriging techniques

This study proposes a novel measurement-based method to predict and model three-dimensional (3-D) path loss in indoor scenarios, which first regresses 28 GHz measurements via median path loss modeling and then includes ordinary Kriging to interpolate shadowing. The performance of this method is evaluated by investigating the spatial structure that follows shadowing through the semivariogram, covariance function, and correlogram as variography tools. It is shown that semivariogram outperforms the other statistics to describe shadowing spatial continuity in path loss modeling in terms of the mean absolute error.This work was supported by the National Council of Science and Technology CONACYT, through the student scholarship number 746015, under Project RTI2018-095499-B-C31, funded by the Ministerio de Ciencia, Innovación y Universidades, Gobierno de España (MCIU/AEI/FEDER, UE)

Identification of α-Amylase and α-Glucosidase Inhibitors and Ligularoside A, a New Triterpenoid Saponin from Passiflora ligularis Juss (Sweet Granadilla) Leaves, by a Nuclear Magnetic Resonance-Based Metabolomic Study

Author accepted manuscript[Abstract] The leaves of Passiflora ligularis Juss (known as sweet granadilla for its edible fruits) are a crop byproduct that is discarded. With the aim of contributing to give value-added products from these crop by-side products to farmers of Colombian Andes, we carried out a 1H-NMR-metabolomics analysis of polar extracts from leaves collected in three locations and stored in two conditions in order to identify glucosyl-hydrolase inhibitors. Variations in the metabolic profile and the bioactivity among samples were analyzed by orthogonal partial least square discriminant analysis. Thus, 1H-NMR signals related to polyphenolic compounds, saponins, and amino acids were correlated with higher inhibitory activities. Moreover, a targeted NMR and HPLC–MS/MS analysis allowed the identification of 14 polyphenolic compounds and the structural characterization of a new triterpenoid saponin, ligularoside A. The measurements of IC50 values for α-amylase and α-glycosidase inhibitors allowed the identification of quercetin-3-O-β-glucoside, kaempferol-3-O-β-glucoside, and ligularoside A as the most active compounds. These results suggest that P. ligularis leaves are a source of glucosyl-hydrolase inhibitors and lay the foundation for exploring additional applications.This research was financially supported by the Colombia Department of Science, Technology and Innovation COLCIENCIAS through the project “Estudio de la actividad antidiabética de un extracto nanovehículizado de hojas de Passiflora ligularis (granadilla)” contract 836/2017. This work was also supported by grant RTI2018-093634-B-C22 (AEI/FEDER, EU) from the State Agency for Research (AEI) of Spain, co-funded by the FEDER Programme from the European Union, and BLUEBIOLAB (0474_BLUEBIOLAB_1_E), Programme INTERREG V A of Spain-Portugal (POCTEP)Colombia.Colciencias; 836/201

Influencia del enfriamiento en las propiedades de titanatos de lantano y litio

Se ha estudiado el efecto de los tratamientos a alta temperatura sobre la estructura y la movilidad del litio para la solución sÛlida Li3xLa2/3-xTiO3 (0.03<x<0.167) con difracciÛn de rayos X a alta temperatura (DRXAT), espectroscopia Raman, RMN y de impedancias. Los patrones de difracción de rayos X (DRX) a temperatura ambiente de muestras enfriadas lentamente muestran una estructura tipo perovskita doblada en el eje c con simetrÌas tetragonales u ortorrómbicas, mientras que las muestras con un enfriamiento r·pido muestran una estructura tipo perovskita c ̇bica simple. Sin embargo, el espectro Raman de las muestras analizadas se interpreta, en todos los casos, con una simetrÌa tetragonal en la que el desorden catiónico se incrementa con el contenido de litio y el tratamiento de enfriamiento. La existencia de microdominios de maclado, orientados a lo largo de las tres direcciones de la perovski- ta, favorece la detecciÛn de la fase c ̇bica en los patrones de DRX. A partir de la espectroscopia de RMN del 7Li, se ha detectado un movimiento bidi- mensional del litio en las muestras ordenadas, el cual se convierte progresivamente en un movimiento tridimensional conforme se incrementa el desorden catiÛnico. Asimismo, la presencia de microdominios hace disminuir la conductividad dc de muestras con contenidos bajos de litio

Erosivity of precipitations in Tandil, province of Buenos Aires

The objective of this paper was to evaluate the utility of a short period pluviografic data for the estimation of the monthly and annual erosivity in Dique Seco, Tandil, Buenos Aires, Argentina. The methodology used by the Universal Soil Loss Equation (USLE) for calculation of the R factor was applied to a 1972-1977 serie, and the results compared with other published data. A close relationship between the product of the total volume of a storm by the maximum intensity in 30 minutes and the R factor was confirmed. The coefficients of adjustment Bi was applied. A higher rain erosivity was confirmed for the spring and summer months.Facultad de Ciencias Agrarias y Forestale

Edible mechanical metamaterials with designed fracture for mouthfeel control

Metamaterials can display unusual and superior properties that come from their carefully designed structure rather than their composition. Metamaterials have permeated large swatches of science, including electromagnetics and mechanics. Although metamaterials hold the promise for realizing technological advances, their potential to enhance interactions between humans and materials has largely remained unexplored. Here, we devise a class edible mechanical metamaterials with tailored fracture properties to control mouthfeel sensory experience. Using chocolate as a model material, we first demonstrate how to create and control the fracture anisotropy, and the number of cracks, and demonstrate that these properties are captured in mouthfeel experience. We further use topology optimization to rationally design edible metamaterials with maximally anisotropic fracture strength. Our work opens avenues for the use of metamaterials to control fracture and to enhance human-matter interactions

Erosivity of precipitations in Tandil, province of Buenos Aires

The objective of this paper was to evaluate the utility of a short period pluviografic data for the estimation of the monthly and annual erosivity in Dique Seco, Tandil, Buenos Aires, Argentina. The methodology used by the Universal Soil Loss Equation (USLE) for calculation of the R factor was applied to a 1972-1977 serie, and the results compared with other published data. A close relationship between the product of the total volume of a storm by the maximum intensity in 30 minutes and the R factor was confirmed. The coefficients of adjustment Bi was applied. A higher rain erosivity was confirmed for the spring and summer months.Facultad de Ciencias Agrarias y Forestale