265 research outputs found

    Methods to Monitor and Quantify Autophagy in the Social Amoeba Dictyostelium discoideum

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    Autophagy is a eukaryotic catabolic pathway that degrades and recycles cellular components to maintain homeostasis. It can target protein aggregates, superfluous biomolecular complexes, dysfunctional and damaged organelles, as well as pathogenic intracellular microbes. Autophagy is a dynamic process in which the different stages from initiation to final degradation of cargo are finely regulated. Therefore, the study of this process requires the use of a palette of techniques, which are continuously evolving and whose interpretation is not trivial. Here, we present the social amoeba Dictyostelium discoideum as a relevant model to study autophagy. Several methods have been developed based on the tracking and observation of autophagosomes by microscopy, analysis of changes in expression of autophagy genes and proteins, and examination of the autophagic flux with various techniques. In this review, we discuss the pros and cons of the currently available techniques to assess autophagy in this organism

    Performance of soybean seedlings upon nutrient application by seed coating

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    The aim of this study was to evaluate the effect of different seed coatings consisting of various combinations of three nutrients (calcium, magnesium and silicon) on two soybean cultivars (BRS 243 RR and CD 233 RR). Dolomitic limestone and aluminum silicate were chosen as the nutrient sources. Leaf area, plant height, shoots dry matter, crop growth rate, relative growth rate and net assimilation rate were the studied variables, evincing that the seed coating that comprised calcium, magnesium and silicon led to better performance in terms of growth rates 30 days after emergence. Significant differences in the response to the seed coatings were also observed between the two studied soybean genotypes

    The High Cadence Transit Survey (HiTS): Compilation and Characterization of Light-curve Catalogs

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    Indexación: Scopus.J.M. acknowledges support from CONICYT-Chile through CONICYT-PCHA/Doctorado-Nacional/2014-21140892. J.M., F.F., G.C.V., and G.M. acknowledge support from the Ministry of Economy, Development, and Tourism’s Millennium Science Initiative through grant IC120009, awarded to the Millennium Institute of Astrophysics (MAS). F.F. acknowledges support from Conicyt through the Fondecyt Initiation into Research project No. 11130228. J.M., F.F., J.S.M., G.C.V., and S.G. acknowledge support from Basal Project PFB-03, Centro de Modelamiento Matemáico (CMM), Universidad de Chile. P.L. acknowledges support by Fondecyt through project #1161184. G.C.V. gratefully acknowledges financial support from CON-ICYT-Chile through FONDECYT postdoctoral grant number 3160747 and CONICYT-Chile and NSF through the Programme of International Cooperation project DPI201400090. P.H. acknowledges support from FONDECYT through grant 1170305. L.G. was supported in part by the US National Science Foundation under grant AST-1311862. G.M. acknowledges support from Conicyt through CONICYT-PCHA/Magís-terNacional/2016-22162353. Support for T.d.J. has been provided by US NSF grant AST-1211916, the TABASGO Foundation, and Gary and Cynthia Bengier. R.R.M. acknowledges partial support from BASAL Project PFB-06, as well as FONDECYT project N◦1170364. Powered@NLHPC: this research was supported by the High Performance Computing infrastructure of the National Laboratory for High Performance Computing (NLHPC), PIA ECM-02, CONICYT. This project used data obtained with the Dark Energy Camera (DECam), which was constructed by the Dark Energy Survey (DES) collaborating institutions: Argonne National Lab, the University of California Santa Cruz, the University of Cambridge, Centro de Investigaciones Energeticas, Medioambientales y Tecnologi-cas-Madrid, the University of Chicago, University College London, the DES-Brazil consortium, the University of Edinburgh, ETH-Zurich, the University of Illinois at Urbana-Champaign, Institut de Ciencies de l’Espai, Institut de Fisica d’Altes Energies, Lawrence Berkeley National Lab, Ludwig-Maximilians Universitat, the University of Michigan, the National Optical Astronomy Observatory, the University of Nottingham, Ohio State University, the University of Pennsylvania, the University of Portsmouth, SLAC National Lab, Stanford University, the University of Sussex, and Texas A&M University. Funding for DES, including DECam, has been provided by the U.S. Department of Energy, National Science Foundation, Ministry of Education and Science (Spain), Science and Technology Facilities Council (UK), Higher Education Funding Council (England), National Center for Supercomputing Applications, Kavli Institute for Cosmological Physics, Financia-dora de Estudos e Projetos, Fundação Carlos Chagas Filho de Amparo a Pesquisa, Conselho Nacional de Desenvolvimento Científico e Tecnológico and the Ministério da Ciência e Tecnologia (Brazil), the German Research Foundation-sponsored cluster of excellence “Origin and Structure of the universe,” and the DES collaborating institutions. Facility: CTIO:1.5 m (DECam).The High Cadence Transient Survey (HiTS) aims to discover and study transient objects with characteristic timescales between hours and days, such as pulsating, eclipsing, and exploding stars. This survey represents a unique laboratory to explore large etendue observations from cadences of about 0.1 days and test new computational tools for the analysis of large data. This work follows a fully data science approach, from the raw data to the analysis and classification of variable sources. We compile a catalog of ∼15 million object detections and a catalog of ∼2.5 million light curves classified by variability. The typical depth of the survey is 24.2, 24.3, 24.1, and 23.8 in the u, g, r, and i bands, respectively. We classified all point-like nonmoving sources by first extracting features from their light curves and then applying a random forest classifier. For the classification, we used a training set constructed using a combination of cross-matched catalogs, visual inspection, transfer/active learning, and data augmentation. The classification model consists of several random forest classifiers organized in a hierarchical scheme. The classifier accuracy estimated on a test set is approximately 97%. In the unlabeled data, 3485 sources were classified as variables, of which 1321 were classified as periodic. Among the periodic classes, we discovered with high confidence one δ Scuti, 39 eclipsing binaries, 48 rotational variables, and 90 RR Lyrae, and for the nonperiodic classes, we discovered one cataclysmic variable, 630 QSOs, and one supernova candidate. The first data release can be accessed in the project archive of HiTS (http://astro.cmm.uchile.cl/HiTS/). © 2018. The American Astronomical Society. All rights reserved.https://iopscience.iop.org/article/10.3847/1538-3881/aadfd

    Benchmark low-mass objects in Moving Groups

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    This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.In order to compile a sample of ultracool dwarfs that will serve as benchmarks for testing theoretical formation and evolutionary models, we selected low-mass cool (>M7) objects that are potentially members of five known young Moving Groups in the solar neighbourhood. We have studied the kinematics of the sample, finding that 49 targets belong to the young disk area, from which 36 are kinematic member of one of the five moving groups under study. Some of the identified low-mass members have been spectroscopically characterised (T-eff, log g) and confirmed as young members through a detailed study of age indicators

    Correlación entre la medida del color del fruto y la concentración de sólidos solubles totales en frutilla o fresa (Fragaria ananassa Duch.) = Correlation between fruit color measurement and total soluble solids concentration in strawberry (Fragaria ananassa Duch.)

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    La cuantificación de la calidad de la frutilla se realiza generalmente mediante la determinación de la cantidad de sólidos solubles totales (SST) utilizando técnicas refractométricas. El objetivo de este trabajo fue correlacionar estas medidas de calidad con los parámetros obtenidos durante la determinación del color de los frutos utilizando dos instrumentos colorimétricos distintos. El estudio se realizó en frutos de tres variedades de frutilla ('Camarosa', 'Florida Festival' y 'Camino Real') obtenidos durante la temporada 2013 en la Estación Experimental Agropecuaria Famaillá – INTA. En cada fruto se midió el contenido de SST y las colorimétricas en dos espacios de color diferentes. Se ajustaron distintos modelos para obtener la mejor correlación entre ambas medidas. Los ajustes mostraron que la mejor correlación se obtiene utilizando el espacio de color CIE L*a*b*. Además, el ajuste más significativo se obtuvo apelando a la variable a*, que codifica la cantidad de rojo del fruto. Sin embargo, los errores del ajuste no permiten obtener una predicción precisa de la calidad a partir de la determinación del color. El error se encuentra en el orden de ± 3 °Brix.Quality assessment in strawberries is generally performed through refractometric techniques to determine total soluble solids (TSS). The objective of this work was to establish the correlation between fruit quality and two different set of color parameters obtained through two colorimetric instruments. Three varieties of strawberries were harvested ('Camarosa', 'Florida Festival' and 'Camino Real') from the Estación Experimental Agropecuaria Famaillá – INTA, throughout the season 2013. In each fruit TSS content and colorimetric variables in two different color spaces were measured.We looked for the best correlating model within two color spaces and we found that the best correlation was reached with only the a* parameter from the CIE L*a*b* color space. However, the error in the prediction of fruit quality based on color measurement was in the order of ±3° Brix.EEA FamailláFil: Solórzano, A.C. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucuman. Instituto de Investigacion En Luz, Ambiente y Vision; ArgentinaFil: Martín, A. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucuman. Instituto de Investigacion En Luz, Ambiente y Vision; Argentina. UTN Regional Tucumán, ArgentinaFil: Salazar, Sergio Miguel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Famaillá; Argentina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Sandoval, J.S. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucuman. Instituto de Investigacion En Luz, Ambiente y Vision; Argentina. Universidad Nacional de Tucuman. Facultad de Cs.exactas y Tecnologia. Departamento de Luminotecnia, Luz y Vision; ArgentinaFil: Kirschbaum, Daniel Santiago. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Famaillá; Argentin

    Phase diagram of a superconductor / ferromagnet bilayer

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    The magnetic field (H) - temperature (T) phase diagram of a superconductor is significantly altered when domains are present in an underlying ferromagnet with perpendicular magnetic anisotropy. When the domains have a band-like shape, the critical temperature Tc of the superconductor in zero field is strongly reduced, and the slope of the upper critical field as a function of T is increased by a factor of 2.4 due to the inhomogeneous stray fields of the domains. Field compensation effects can cause an asymmetric phase boundary with respect to H when the ferromagnet contains bubble domains. For a very inhomogeneous domain structure, Tc~H^2 for low H and Tc~H for higher fields, indicating a dimensional crossover from a one-dimensional network-like to a two-dimensional behavior in the nucleation of superconductivity.Comment: 6 pages, 7 figure

    IgG anti-high density lipoprotein antibodies are elevated in abdominal aortic aneurysm and associated with lipid profile and clinical features

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    High-density lipoproteins cholesterol (HDLc) levels are decreased in abdominal aortic aneurysm (AAA), which is hallmarked by autoimmunity and lipid aortic deposits. To investigate whether IgG anti-HDL antibodies were present in AAA and their potential association with clinical features, IgG anti-HDL and total IgG along with HDLc plasma levels were measured in 488 AAA patients and 184 controls from the Viborg Vascular (VIVA) study, and in tissue-conditioned media from AAA intraluminal thrombus and media layer samples compared to control aortas. Higher IgG anti-HDL levels were found in AAA compared to controls, even after correcting for total IgG, and after adjusting for potential confounders. IgG anti-HDL levels were correlated with aortic diameter in univariate and adjusted multivariate analyses. IgG anti-HDL antibodies were negatively associated with HDLc levels before and after correcting for potential confounders. Increased anti-HDL antibodies were identified in tissue-conditioned media from AAA samples compared to healthy aortas, with higher levels being observed in the media layer. In conclusion, increased IgG anti-HDL levels (both in plasma and in tissue) are linked to AAA, associated with aortic diameter and HDLc levels. These data suggest a potential immune response against HDL in AAA and support an emerging role of anti-HDL antibodies in AAA

    Orientational pinning and transverse voltage: Simulations and experiments in square Josephson junction arrays

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    We study the dependence of the transport properties of square Josephson Junctions arrays with the direction of the applied dc current, both experimentally and numerically. We present computational simulations of current-voltage curves at finite temperatures for a single vortex in the array (Ha2/Φ0=f=1/L2Ha^2/\Phi_0=f=1/L^2), and experimental measurements in 100×1000100\times1000 arrays under a low magnetic field corresponding to f0.02f\approx0.02. We find that the transverse voltage vanishes only in the directions of maximum symmetry of the square lattice: the [10] and [01] direction (parallel bias) and the [11] direction (diagonal bias). For orientations different than the symmetry directions, we find a finite transverse voltage which depends strongly on the angle ϕ\phi of the current. We find that vortex motion is pinned in the [10] direction (ϕ=0\phi=0), meaning that the voltage response is insensitive to small changes in the orientation of the current near ϕ=0\phi=0. We call this phenomenon orientational pinning. This leads to a finite transverse critical current for a bias at ϕ=0\phi=0 and to a transverse voltage for a bias at ϕ0\phi\not=0. On the other hand, for diagonal bias in the [11] direction the behavior is highly unstable against small variations of ϕ\phi, leading to a rapid change from zero transverse voltage to a large transverse voltage within a few degrees. This last behavior is in good agreement with our measurements in arrays with a quasi-diagonal current drive.Comment: 9 pages, 9 figure

    Storm evolution characterization for analysing stone armour damage progression

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    Storm evolution is fundamental for analysing the damage progression of the different failure modes and establishing suitable protocols for maintaining and optimally sizing structures. However, this aspect has hardly been studied and practically the whole of the studies dealing with the subject adopt the Equivalent triangle storm. As against this approach, two new ones are proposed. The first is the Equivalent Triangle Magnitude Storm model (ETMS), whose base, the triangular storm duration, D, is established such that its magnitude (area describing the storm history above the reference threshold level which sets the storm condition),HT, equals the real storm magnitude. The other is the Equivalent Triangle Number of Waves Storm (ETNWS), where the base is referred in terms of the real storm's number of waves,Nz. Three approaches are used for estimating the mean period, Tm, associated to each of the sea states defining the storm evolution, which is necessary to determine the full energy flux withstood by the structure in the course of the extreme event. Two are based on the Jonswap spectrum representativity and the other uses the bivariate Gumbel copula (Hs, Tm), resulting from adjusting the storm peaks. The representativity of the approaches proposed and those defined in specialised literature are analysed by comparing the main armour layer's progressive loss of hydraulic stability caused by real storms and that relating to theoretical ones. An empirical maximum energy flux model is used for this purpose. The agreement between the empirical and theoretical results demonstrates that the representativity of the different approaches depends on the storm characteristics and point towards a need to investigate other geometrical shapes to characterise the storm evolution associated with sea states heavily influenced by swell wave components
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