The low mass end of the neutral gas mass and velocity width functions of galaxies in Λ\LambdaCDM

We use the high-resolution Aquarius cosmological dark matter simulations coupled to the semi-analytic model by Starkenburg et al. (2013) to study the HI content and velocity width properties of field galaxies at the low mass end in the context of $\Lambda$CDM. We compare our predictions to the observed ALFALFA survey HI mass and velocity width functions, and find very good agreement without fine-tuning, when considering central galaxies. Furthermore, the properties of the dark matter halos hosting galaxies, characterised by their peak velocity and circular velocity at 2 radial disk scalelengths overlap perfectly with the inferred values from observations. This suggests that our galaxies are placed in the right dark matter halos, and consequently at face value, we do not find any discrepancy with the predictions from the $\Lambda$CDM model. Our analysis indicates that previous tensions, apparent when using abundance matching models, arise because this technique cannot be straightforwardly applied for objects with masses $M_{vir} < 10^{10} M_{\odot}$.Comment: Accepted for publication in MNRAS, 9 pages, 8 figure

Actividad antagónica de una cepa de Bacillus sp. aislada en Córdoba, Argentina contra Macrophomina phaseolina (Tassi) Goid

The antifungal activity of Bacillus spp.strains has been already reported against a different number of phytopathogenicfungi3. Some species belonging to thisgenus (i.e. B. subtilis, B. pumilus and B. licheniformis) are considered GRAS (generally regarding as safe) microorganisms and exhibit potential to enhance plant growth by the production of an amplenumber of beneficial substances1,portraying these species as an environmentally friendly alternative tochemical fungicides. Macrophomina phaseolina (Tassi) Goid is a wide range soil-bornephytopathogenic fungus causing charcoal rot to several significant plant crops in Argentina (i.e. soybean, common bean,peanuts and corn)5,6 and is also capableto affect more than five hundred plant species worldwide4. Its ability to infect these hostplants is commonly correlated to the production of viable sclerotia, anon-sporic resistance structure constituted by a mass of densely packed hyphae, in the field5. In this work, we report theisolation of a Bacillus sp. strain 11.1 obtained from soil samples from Córdoba Province,Argentina2exhibiting a strongantagonistic activity against M. phaseolina. In order to analyse thepotential antagonistic effect of strain 11.1, both microorganisms were grown on dual culture platescontained potato dextrose agar (PDA) and tryptone soya agar (TSA) (1:1 v/v) and incubated for 48-72hours at 28ºC (Figure 1). An important and irreversible inhibition of the fungal growth was showed (Figure1A). In addition, the fungal mycelium located at the edge of the inhibited region was analysed bymicroscopic examination. The most evident antagonistic effect over the fungus was depicted by the lack ofblack pigmentation and the reduced size of formed sclerotiain comparison with the control (Figure 1B and C).Fil: Felipe, Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones y Transferencia de Villa María. Universidad Nacional de Villa María. Centro de Investigaciones y Transferencia de Villa María; ArgentinaFil: Palma, Leopoldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones y Transferencia de Villa María. Universidad Nacional de Villa María. Centro de Investigaciones y Transferencia de Villa María; ArgentinaFil: Yaryura, Pablo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones y Transferencia de Villa María. Universidad Nacional de Villa María. Centro de Investigaciones y Transferencia de Villa María; Argentin

Xanthan pyruvilation is essential for the virulence of Xanthomonas campestris pv. campestris

Xanthan, the main exopolysaccharide (EPS) synthesized by Xanthomonas spp., contributes to bacterial stress tolerance and enhances attachment to plant surfaces by helping in biofilm formation. Therefore, xanthan is essential for successful colonization and growth in planta and has also been proposed to be involved in the promotion of pathogenesis by calcium ion chelation and, hence, in the suppression of the plant defense responses in which this cation acts as a signal. The aim of this work was to study the relationship between xanthan structure and its role as a virulence factor. We analyzed four Xanthomonas campestris pv. campestris mutants that synthesize structural variants of xanthan. We found that the lack of acetyl groups that decorate the internal mannose residues, ketal-pyruvate groups, and external mannose residues affects bacterial adhesion and biofilm architecture. In addition, the mutants that synthesized EPS without pyruvilation or without the external mannose residues did not develop disease symptoms in Arabidopsis thaliana. We also observed that the presence of the external mannose residues and, hence, pyruvilation is required for xanthan to suppress callose deposition as well as to interfere with stomatal defense. In conclusion, pyruvilation of xanthan seems to be essential for Xanthomonas campestris pv. campestris virulence.Fil: Bianco, María Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencia y Tecnología "Dr. César Milstein". Fundación Pablo Cassará. Instituto de Ciencia y Tecnología ; ArgentinaFil: Toum, Laila. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencia y Tecnología "Dr. César Milstein". Fundación Pablo Cassará. Instituto de Ciencia y Tecnología ; ArgentinaFil: Yaryura, Pablo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones y Transferencia de Villa María. Universidad Nacional de Villa María. Centro de Investigaciones y Transferencia de Villa María; ArgentinaFil: Mielnichuk, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencia y Tecnología "Dr. César Milstein". Fundación Pablo Cassará. Instituto de Ciencia y Tecnología ; ArgentinaFil: Gudesblat, Gustavo Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencia y Tecnología "Dr. César Milstein". Fundación Pablo Cassará. Instituto de Ciencia y Tecnología ; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Roeschlin, Roxana Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Marano, María Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Ielpi, Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Vojnov, Adrián Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencia y Tecnología "Dr. César Milstein". Fundación Pablo Cassará. Instituto de Ciencia y Tecnología ; Argentin

Implementación de encuestas en línea como herramienta para el análisis del mantenimiento industrial en España y otros temas afines

[ES] El presente trabajo tiene el objetivo de investigar y analizar el Mantenimiento en España. El método de toma de datos es a través de la encuesta El Mantenimiento en España. Edición 2020 , la cual, se ejecuta en colaboración con la Asociación Española de Mantenimiento (AEM). La plataforma para gestionar y extraer los datos es el programa Limesurvey, la cual permite realizar la encuesta en línea (on-line) y almacenar los datos en una nube particular. La encuesta esta dirigida a los responsables de Mantenimiento o personal que esté involucrado directamente en las funciones del área y son agrupados en los siguientes sectores: Alimentación, automóvil e industria auxiliar, construcción, construcciones electromecánicas, edificios, empresas diversas, energía, química y proceso, siderometalurgia y transporte e infraestructura. Los temas tratados en la encuesta van desde la propia organización del Mantenimiento, sus costes, el Mantenimiento contratado, así como información acerca de la informatización del Mantenimiento, formación del personal, dirección de Mantenimiento, gestión de activos. De manera particular, en esta edición se introducen como novedad temas como: Facility Management , digitalización, fiabilidad y la participación de la mujer en el Mantenimiento. Se realiza el análisis de las preguntas en conjunto y agrupadas por sector y en función del tamaño expresado por el número de empleados. No obstante, se realiza una comparación con los resultados de las versiones anteriores para verificar las tendencias de los resultados.[EN] The work has been focused to research and analyze the Maintenance status in Spain. The method of data collection is a survey El Mantenimiento en España. Edición 2020 . The survey is carried out in collaboration with the Spanish Maintenance Association (AEM). The platform to manage and collect the results is the program Limesurvey. This program allows to perform the survey online and storage the information in the cloud. The survey is addressed to the Maintenance managers or personnel that is directly involved in the area, and it is grouped on the following sectors: Automotive, buildings, chemical and process, construction, miscellanea companies, electromechanics constructions, energy, food, metallurgy and transportation. The topics considered in the survey are: Maintenance organization, costs, externalized maintenance, computerization, personnel training, Maintenance management and asset management. Also, for this new issue there are some topics that have been introduced for the first time: women involvement on industrial Maintenance, facility management, digitalization and reliability. Results obtained are analyzed in general and also by the different sectors considered or company size expressed by the number of employees. After such study, the results are compared with those obtained on previous editions to verify it there is any change of the tendency or a meaning behavior that must be studied particularly.Yaryura Paulino, YR. (2020). Implementación de encuestas en línea como herramienta para el análisis del mantenimiento industrial en España y otros temas afines. Universitat Politècnica de València. http://hdl.handle.net/10251/153081TFG

Calibration of semi-analytic models of galaxy formation using Particle Swarm Optimization

We present a fast and accurate method to select an optimal set of parameters in semi-analytic models of galaxy formation and evolution (SAMs). Our approach compares the results of a model against a set of observables applying a stochastic technique called Particle Swarm Optimization (PSO), a self-learning algorithm for localizing regions of maximum likelihood in multidimensional spaces that outperforms traditional sampling methods in terms of computational cost. We apply the PSO technique to the SAG semi-analytic model combined with merger trees extracted from a standard $\Lambda$CDM N-body simulation. The calibration is performed using a combination of observed galaxy properties as constraints, including the local stellar mass function and the black hole to bulge mass relation. We test the ability of the PSO algorithm to find the best set of free parameters of the model by comparing the results with those obtained using a MCMC exploration. Both methods find the same maximum likelihood region, however the PSO method requires one order of magnitude less evaluations. This new approach allows a fast estimation of the best-fitting parameter set in multidimensional spaces, providing a practical tool to test the consequences of including other astrophysical processes in SAMs.Comment: 11 pages, 4 figures, 1 table. Accepted for publication in ApJ. Comments are welcom

The brightest group galaxies and their large-scale environment

We use a sample of galaxy groups in SDSS data to study their brightestgalaxies (BGG), separating groups according to their large scale environment. The statistical properties of the BGG depend on the surrounding environment on large scales, characterized by the high density peaks within Future Virialized Structures (FVS). We also find that the luminosity, colour, stellar masses and concentration index of the BGG hosted by groups in superstructures are different, with statistical significance, from the corresponding properties of BGG hosted by groups elsewhere. Moreover, this signal is strongly dominated by disk-type galaxies.The results reveal connections between the large scale environment and the accretion process onto the brightest group galaxies.Estudiamos las galaxias más luminosas (del inglés Brightest Group Galaxy, BGG) de una muestra de grupos de galaxias en el SDSS, discriminando submuestras de grupos según su estructura circundante en gran escala. Encontramos que las propiedades de las BGG dependen del ambiente en gran escala, caracterizado por su pertenencia a los picos de densidad dentro de estructuras virializadas en el futuro (del inglés Future Virialized Structures, FVS). Los valores de luminosidad, índice de color, masa estelar e índice de concentración de las BGG alojadas en grupos en FVS difieren con significancia estadística de aquellas que no se encuentran en superestructuras. Esta señal está dominada por galaxias tipo disco. Estos resultados revelan conexiones entre la estructura en gran escala y los procesos de aglomeración de masa en grupos de galaxias.http://adsabs.harvard.edu/abs/2015BAAA...57...67LpublishedVersionFil: Luparello, Heliana E. Conicet. Instituto de Astronomía Teórica y Experimental; Argentina.Fil: Lares Harbin Latorre, Marcelo. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Fil: Luparello, Heliana E. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Fil: Lares Harbin Latorre, Marcelo. Conicet. Instituto de Astronomía Teórica y Experimental; Argentina.Fil: Paz, Dante Javier. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Fil: Paz, Dante Javier. Conicet. Instituto de Astronomía Teórica y Experimental; Argentina.Fil: Yaryura, Claudia Yamila. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Fil: Yaryura, Claudia Yamila. Conicet. Instituto de Astronomía Teórica y Experimental; Argentina.Fil: Lambas, Diego García. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Fil: Lambas, Diego García. Conicet. Instituto de Astronomía Teórica y Experimental; Argentina.Astronomía (incluye Astrofísica y Ciencias del Espacio

Environmental effects on associations of dwarf galaxies

We study the properties of associations of dwarf galaxies and their dependence on the environment. Associations of dwarf galaxies are extended systems composed exclusively of dwarf galaxies, considering as dwarf galaxies those galaxies less massive than $M_{\star, \rm max} = 10^{9.0}$ ${\rm M}_{\odot}\,h^{-1}$. We identify these particular systems using a semi-analytical model of galaxy formation coupled to a dark matter only simulation in the $\Lambda$ Cold Dark Matter cosmological model. To classify the environment, we estimate eigenvalues from the tidal field of the dark matter particle distribution of the simulation. We find that the majority, two thirds, of associations are located in filaments ($\sim 67$ per cent), followed by walls ($\sim 26$ per cent), while only a small fraction of them are in knots ($\sim 6$ per cent) and voids ($\sim 1$ per cent). Associations located in more dense environments present significantly higher velocity dispersion than those located in less dense environments, evidencing that the environment plays a fundamental role in their dynamical properties. However, this connection between velocity dispersion and the environment depends exclusively on whether the systems are gravitational bound or unbound, given that it disappears when we consider associations of dwarf galaxies that are gravitationally bound. Although less than a dozen observationally detected associations of dwarf galaxies are currently known, our results are predictions on the eve of forthcoming large surveys of galaxies, which will enable these very particular systems to be identified and studied.Comment: 13 pages, 9 figures. Accepted for publication in MNRA

Extreme value statistics of smooth random Gaussian fields

We consider the Gumbel or extreme value statistics describing the distribution function p_G(x_max) of the maximum values of a random field x within patches of fixed size. We present, for smooth Gaussian random fields in two and three dimensions, an analytical estimate of p_G which is expected to hold in a regime where local maxima of the field are moderately high and weakly clustered. When the patch size becomes sufficiently large, the negative of the logarithm of the cumulative extreme value distribution is simply equal to the average of the Euler Characteristic of the field in the excursion x > x_max inside the patches. The Gumbel statistics therefore represents an interesting alternative probe of the genus as a test of non Gaussianity, e.g. in cosmic microwave background temperature maps or in three-dimensional galaxy catalogs. It can be approximated, except in the remote positive tail, by a negative Weibull type form, converging slowly to the expected Gumbel type form for infinitely large patch size. Convergence is facilitated when large scale correlations are weaker. We compare the analytic predictions to numerical experiments for the case of a scale-free Gaussian field in two dimensions, achieving impressive agreement between approximate theory and measurements. We also discuss the generalization of our formalism to non-Gaussian fields.Comment: 10 pages, 2 figures, accepted for publication in MNRA