Cosmological black holes and the direction of time

Macroscopic irreversible processes emerge from fundamental physical laws of reversible character. The source of the local irreversibility seems to be not in the laws themselves but in the initial and boundary conditions of the equations that represent the laws. In this work we propose that the screening of currents by black hole event horizons determines, locally, a preferred direction for the flux of electromagnetic energy. We study the growth of black hole event horizons due to the cosmological expansion and accretion of cosmic microwave background radiation, for different cosmological models. We propose generalized McVittie co-moving metrics and integrate the rate of accretion of cosmic microwave background radiation onto a supermassive black hole over cosmic time. We find that for flat, open, and closed Friedmann cosmological models, the ratio of the total area of the black hole event horizons with respect to the area of a radial co-moving space-like hypersurface always increases. Since accretion of cosmic radiation sets an absolute lower limit to the total matter accreted by black holes, this implies that the causal past and future are not mirror symmetric for any spacetime event. The asymmetry causes a net Poynting flux in the global future direction; the latter is in turn related to the ever increasing thermodynamic entropy. Thus, we expose a connection between four different "time arrows": cosmological, electromagnetic, gravitational, and thermodynamic.Comment: 13 pages, 2 figures in Foundations of Science (2017

Limit cycles in the Holling-Tanner model

This paper deals with the following question: does the asymptotic stability of the positive equilibrium of the Holling-Tanner model imply it is also globally stable? We will show that the answer to this question is negative. The main tool we use is the computation of Poincaré-Lyapunov constants in case a weak focus occurs. In this way we are able to construct an example with two limit cycles

A logical study of local and global graded similarities

In this work we study the relationship between global and local similarities in the graded framework of fuzzy class theory (FCT), in which there already exists a graded notion of similarity. In FCT we can express the fact that a fuzzy relation is reflexive, symmetric, or transitive up to a certain degree, and similarity is defined as a first-order sentence, which is the fusion of three sentences corresponding to the graded notions of reflexivity, symmetry, and transitivity. This allows us to speak in a natural way of the degree of similarity of a relation. We consider global similarities defined from local similarities using t-norms as aggregation operators, and we obtain some results in the framework of FCT that, adequately interpreted, allow us to say that when we take a t-norm as an aggregation operator, the properties of reflexivity, symmetry, and transitivity of fuzzy binary relations are inherited from the local to the global level, and that the global similarity is a congruence if some of the local similarities are congruence

Global periodicity conditions for maps and recurrences via Normal Forms

We face the problem of characterizing the periodic cases in parametric families of (real or complex) rational diffeomorphisms having a fixed point. Our approach relies on the Normal Form Theory, to obtain necessary conditions for the existence of a formal linearization of the map, and on the introduction of a suitable rational parametrization of the parameters of the family. Using these tools we can find a finite set of values p for which the map can be p-periodic, reducing the problem of finding the parameters for which the periodic cases appear to simple computations. We apply our results to several two and three dimensional classes of polynomial or rational maps. In particular we find the global periodic cases for several Lyness type recurrences.Comment: 25 page

Identification of inoculum sources of Fusicladium eriobotryae in loquat orchards in Spain

[EN] Fusicladium eriobotryae is the causal agent of loquat scab, the main disease damaging fruit, leaves and young twigs of this crop. A two-growing season study (2015¿2016 and 2016¿2017) was carried out in two loquat orchards (cv ¿Algerie¿) to determine the inoculum sources of F. eriobotryae by direct observation of conidia, pathogen isolation on culture media and detection using a new real time PCR protocol developed in this study. One-year-old twigs, fruit peduncles and fruit mummies were randomly sampled three times per growing season on each orchard, and inflorescences only at flowering. Conidia of F. eriobotryae were not found and the isolation of the pathogen was neither possible from any sample in both seasons. Specific primers FUG2F and FUG2R, were designed to detect and quantify DNA of F. eriobotryae on plant material, with a limit of detection (LOD) established at 48.6 fg/¿l. The DNA of the pathogen was not detected by real time PCR in fruit mummies nor inflorescences. It was detected in fruit peduncles and twigs in the season 2016¿2017 with concentrations ranging from 50 to 2742 fg/¿l, confirming that this two loquat organs might act as potential inoculum sources for F. eriobotryae. The detection of F. eriobotryae only in this season agrees with the predictions of an epidemiological model for this pathogen. Our results indicate that in years with a high disease pressure, fruit twigs and peduncles might act as a source of inoculum of new infections the following year.This study was funded by Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA) grant number RTA2013-00004-C03-03, and FEDER Funds. G. Elena was supported by the Spanish post-doctoral grant Juan de la Cierva-Formación. We thank the E. Soler from the Cooperativa Agrícola de Callosa d En Sarrià (Alicante, Spain) for his collaboration during orchard sampling, and A. Ramón-Albalat and V. Serra for their technical assistance.Elena-Jiménez, G.; Berbegal Martinez, M.; González Domínguez, E.; Armengol Fortí, J. (2020). Identification of inoculum sources of Fusicladium eriobotryae in loquat orchards in Spain. European Journal of Plant Pathology. 156:425-436. https://doi.org/10.1007/s10658-019-01892-yS425436156Acuña, R. P. (2010). Compendio de bacterias y hongos de frutales y vides en Chile. Santiago de Chile: Servicio Agrícola y Ganadero.Bilodeau, G. J., Koike, S. T., Uribe, P., & Martin, F. N. (2012). Development of an assay for rapid detection and quantification of Verticillium dahliae in soil. Phytopathology, 102, 331–343.Bustin, S. A., Benes, V., Garson, J. A., Hellemans, J., Huggett, J., Kubista, M., Mueller, R., Nolan, T., Pfaffl, M. W., Hipley, G. L., Vandesompele, J., & Wittwer, C. T. (2009). The MIQE guidelines: Minimum information for publication of quantitative real-time PCR experiments. Clinical Chemistry, 55, 611–622.Caballero, P., & Fernández, M. A. (2002). Loquat, production and market. Options Méditerranéennes Serie A, 58, 11–20.Ciliberti, N., Fermaud, M., Languasco, L., & Rossi, V. (2015). Influence of fungal strain, temperature, and wetness duration of infection of grapevine inflorescences and young berry clusteres by Botrytis cinerea. Phytopathology, 105, 325–333.Cullen, D. W., Lees, A. K., Toth, I. K., & Duncan, J. M. (2001). Conventional PCR and real-time quantitative PCR detection of Helminthosporium solani in soil and on potato tubers. European Journal of Plant Pathology, 107, 387–398.Daniëls, B., De Landtsheer, A., Dreesen, R., Davey, M. W., & Keulemans, J. (2012). Real-time PCR as a promising tool to monitor growth of Venturia spp. in scab-susceptible and -resistant apple leaves. European Journal of Plant Pathology, 134, 821–833.Demaree, J. (1924). Pecan scab with special reference to sources of the early spring infections. Journal of Agriculture Research, 28, 321–330.Ghasemkhani, M., Holefors, A., Marttila, S., Dalman, K., Zborowska, A., Rur, M., Rees-George, J., Nybom, H., Everett, K. R., Scheper, R. W. A., & Garkava-Gustavsson, L. (2016). Real-time PCR for detection and quantification, and histological characterization of Neonectria ditissima in apple trees. Trees, 30, 1111–1125.Gisbert, A. D., Besoain, X., Llácer, G., & Badenes, M. L. (2006). Protección de cultivo II, Enfermedades. In M. Agustí, C. Reig, & P. Undurraga (Eds.), El Cultivo del Níspero Japonés (pp. 227–246). Valencia: Gráficas Alcoy.Gladieux, P., Caffier, V., Devaux, M., & Le Cam, B. (2010). Host specific differentiation among populations of Venturia inaequalis causing scab on apple, pyracantha and loquat. Fungal Genetics and Biology, 47, 511–521.González-Domínguez, E., Rossi, V., Armengol, J., & García-Jiménez, J. (2013). Effect of environmental factors on mycelial growth and conidial germination of Fusicladium eriobotryae, and the infection of loquat leaves. Plant Disease, 97, 1331–1338.González-Domínguez, E., Armengol, J., & Rossi, V. (2014a). Development and validation of a weather-based model for predicting infection of loquat fruit by Fusicladium eriobotryae. PLoS One, 9, e107547.González-Domínguez, E., Rossi, V., Michereff, S. J., García-Jiménez, J., & Armengol, J. (2014b). Dispersal of conidia of Fusicladium eriobotryae and spatial patterns of scab in loquat orchards in Spain. European Journal of Plant Pathology, 139, 849–861.González-Domínguez, E., León, M., Armengol, J., & Berbegal, M. (2015). A nested polymerase chain reaction protocol for in planta detection of Fusicladium eriobotryae, causal agent of loquat scab. Journal of Phytopathology, 163, 415–418.González-Domínguez, E., Armengol, J., & Rossi, V. (2017). Biology and epidemiology of Venturia species affecting fruit crops: A review. Frontiers in Plant Science, 8, 1496.Graniti, A. (1993). Olive scab: A review. EPPO Bulletin, 23, 377–384.Gusberti, M., Patocchi, A., Gessler, C., & Broggini, G. A. L. (2012). Quantification of Venturia inaequalis growth in Malus × domestica with quantitative real-time polymerase chain reaction. Plant Disease, 96, 1791–1797.Janick, J. (2011). Predictions for loquat improvement in the next decade. Acta Horticulturae, 887, 25–30.Kumar, S., Stecher, G., & Tamura, K. (2016). MEGA7: Molecular evolutionary genetics analysis version 7.0 for bigger datasets. Molecular Biology and Evolution, 33, 1870–1874.Lalancette, N., McFarland, K., & Burnett, L. (2012). Modelling sporulation of Fusicladium carpophilum on nectarine twig lesions: Relative humidity and temperature effects. Phytopathology, 102, 421–428.Lin, S. Q. (2007). World loquat production and research with special reference to China. Acta Horticulturae, 750, 37–44.Martínez-Calvo, B. J., Badenes, M. L., Llacer, G., Bleiholder, H., Hack, H., & Meier, U. (1999). Phenological growth stages of loquat tree (Eriobotrya japonica (Thunb) Lindl.). Annals of Applied Biology, 134, 353–357.Pilotti, M., Lumia, V., Di Lernia, G., & Brunetti, A. (2012). Development of real-time PCR for in wood-detection of Ceratocystis platani, the agent of canker stain of Platanus spp. European Journal of Plant Pathology, 134, 61–79.Prota, U. (1960). Ricerche sulla «ticchiolatura del Nespolo del Giappone e sul suo agente (Fusicladium eriobotryae Cav.). I. Observazioni sull’epidemiologia della malattia e sui caratteri morfo-biologici del parassita in Sardegna. Studi di Sassari, 8, 175–196.Ptskialadze, L. (1968). The causal agent of loquat scab and its biological characteristics. Review of Applied Mycology, 47, 268.Raabe, R., & Gardner, M. W. (1972). Scab of pyracantha, loquat, Toyon and Kageneckia. Phytopathology, 62, 914–916.Rodríguez, A. (1983). El cultivo del níspero en el valle del Algar-Guadalest. Sociedad Cooperativa de Crédito de. Alicante: Callosa d’En Sarrià.Salerno, M., Somma, V., & Rosciglione, B. (1971). Ricerche sull’epidemiologia della ticchiolatura del nespolo del giappone. Technology Agriculture, 23, 947–956.Sánchez-Torres, P., Hinarejos, R., & Tuset, J. J. (2007a). Fusicladium eriobotryae: hongo causante del moteado del níspero en el Mediterráneo español. Boletín de Sanidad Vegetal. Plagas, 33, 89–98.Sánchez-Torres, P., Hinarejos, R., & Tuset, J. J. (2007b). Identification and characterization of Fusicladium eriobotryae: Fungal pathogen causing mediterranean loquat scab. Acta Horticulturae, 750, 343–347.Sánchez-Torres, P., Hinarejos, R., & Tuset, J. J. (2009). Characterization and pathogenicity of Fusicladium eriobotryae, the fungal pathogen responsible for loquat scab. Plant Disease, 93, 1151–1157.Schena, L., Li Destri Nicosia, M. G., Sanzani, S. M., Faedda, R., Ippolito, A., & Cacciola, S. O. (2013). Development of quantitative PCR detection methods for phytopathogenic fungi and oomycetes. Journal of Plant Pathology, 95, 7–24.Scherm, H., Savelle, A. T., Boozer, R. T., & Foshee, W. G. (2008). Seasonal dynamics of conidial production potential of Fusicladium carpophilum on twig lesions in south eastern peach orchards. Plant Disease, 92, 47–50.Schrader, C., Schielke, A., Ellerbroek, L., & Johne, R. (2012). PCR inhibitors – Occurrence, properties and removal. Journal of Applied Microbiology, 113, 1014–1026.Schubert, K. S., Ritschel, A. R., & Braun, U. B. (2003). A monograph of Fusicladium s. lat. (Hyphomycetes). Schlechtendalia, 9, 1–132.Soler, E., Martínez-Calvo, J., Llácer, G., & Badenes, M. L. (2007). Loquat in Spain: Production and marketing. Acta Horticulturae, 750, 45–47.van Leeuwen, G. C. M., Holb, I. J., & Jeger, M. J. (2002). Factors affecting mummification and sporulation of pome fruit infected by Monilinia fructigena in Dutch orchards. Plant Pathology, 51, 787–793.Villarino, M., Melgarejo, P., Usall, J., Segarra, J., & De Cal, A. (2010). Primary inoculum sources of Monilinia spp. in Spanish peach orchards and their relative importance in brown rot. Plant Disease, 94, 1048–1054.Viruega, J. R., Moral, J., Roca, L. F., Navarro, N., & Trapero, A. (2013). Spilocaea oleagina in olive groves of southern Spain: Survival, inoculum production, and dispersal. Plant Disease, 97, 1549–1556

Elemental ratios in sediments as indicators of ecological processes in Spanish reservoirs

Reservoir sediments are important archives of biogeochemical data, reflecting ecological processes that occur at the watershed system. In this paper, a preliminary study of the limnological significance of major element composition and element ratios in sediments of Spanish reservoirs is presented, by analysing two data-sets from different limnological regions. Reservoirs from Eastern and Western Spain present significant differences in the chemical composition of their sediments: higher average values for calcium and magnesium appear in the Eastern reservoirs, while, in Western Spain, higher mean values are found for alumino-silicate elements (i.e. silicon, aluminium, and potassium), iron and phosphorus. Meaningful ratios are Si/Al and Si/K, that are closely related to energy transport in sedimentary catchments, whereas in siliceous catchments Si/Al is an indicator of chemical weathering. Ca/Al ratio appears related to water mineralization, and, in the Eastern Region, the slope of the regression line between Ca/Al and conductivity reflects catchment mineralogy. In superficial sediments from both Eastern and Western regions, Fe/Al is linked to the authigenic precipitation of iron oxides and appears closely related to sedimentary phosphorus accumulation above background levels.El sedimento de los embalses constituye un importante registro de datos biogeoquímicos, ya que refleja los procesos ecológicos que tienen lugar en el conjunto de la cuenca hidrográfica. A partir del análisis de dos conjuntos de datos obtenidos en distintas regiones limnológicas, se presenta una aproximación preliminar al significado limnológico de la composición química y los cocientes elementales en el sedimento de los embalses españoles. Las regiones Este y Oeste de la Península muestran diferencias significativas en cuanto a composición química del sedimento: los mayores valores promedio en la región Este corresponden a la concentración de calcio y magnesio, mientras que en la región Oeste, los mayores valores medios corresponden a los elementos asociados a los alumino-silicatos (aluminio, silicio y potasio), hierro y fósforo. Los cocientes elementales con mayor significado son: Si/K y Si/Al estrechamente relacionados con la energía de transporte en la región calcárea, mientras que en la región silícica Si/Al es un indicador del proceso de meteorización química. Ca/Al se encuentra asociado a la mineralización del agua, y en la región Este la pendiente de la recta de regresión entre Ca/Al y la conductividad del agua refleja la mineralogía de la cuenca. En ambas regiones, el cociente Fe/Al en el sedimento superficial indica la precipitación endógena de óxidos de hierro y aparece estrechamente asociado a la acumulación de fósforo sedimentario por encima del nivel basal

Nutrient fluxes through boundaries in the hypolimnion of Sau reservoir : expected patterns and unanticipated processes

By contrast to many natural lakes, the summer hypolimnion in advection-dominated systems like canyon-shaped reservoirs is not isolated from direct inputs from the river. This has important implications in the evolution of limnological features of the hypolimnion through the stratified period, especially if the river water directly plunges as a density current into the hypolimnion as a consequence of temperature differences. Taking the Sau Reservoir (Spain) as a prototype for this kind of systems, we present data from 11 years of monitoring to show how the river water entering the reservoir during summer is the main factor determining hypolimnetic nutrient concentrations. The empirical regression approach used all through the paper also stressed the effect of the improvement in water quality experienced by the river during the studied period on the improvement of the water quality stored in the summer hypolimnion of the reservoir. Since the change in river water quality was the consequence of the implementation of remediation measures at the basin scale, we advocate these solutions to manage reservoir eutrophication problems in this type of systems, which, in addition, had other unexpected benefits for the hypolimnetic water quality in Sau Reservoir.A diferencia de muchos lagos naturales, el hipolimnion que se forma en verano en sistemas dominados por la advección, como los embalses que inundan valles profundos y estrechos, no está aislado de las entradas directas desde el río. Esto tiene importantes implicaciones en la evolución de las características limnológicas del hipolimnion durante el periodo de estratificación, especialmente si el agua del río entra al embalse como una corriente de densidad directamente en el hipolimnion debido a diferencias de temperatura. Tomando el Embalse de Sau (España) como prototipo de este tipo de sistemas, mostramos 11 años de datos de un programa de monitoreo para ejemplificar cómo el agua del río que entra en verano al embalse es el factor determinante de la concentración de nutrientes en el hipolimnion. La aproximación de regresión empírica utilizada en el artículo también puso de manifiesto el efecto de la mejora en la calidad del agua que sufrió el río durante el periodo de estudio en la mejora del agua del agua embalsada en el hipolimnion. Ya que esta mejora en el río fue consecuencia de la implementación de medidas de restauración a nivel de la cuenca, promovemos estas soluciones para la gestión de problemas de eutrofización en este tipo de sistemas, que por otra parte mostraron ventajas inesperadas en el caso del hipolimnion del Embalse de Sau

Alkaloids Analysis of Habranthus cardenasianus (Amaryllidaceae), Anti-Cholinesterase Activity and Biomass Production by Propagation Strategies

Plants in the Amaryllidaceae family synthesize a diversity of bioactive alkaloids. Some of these plant species are not abundant and have a low natural multiplication rate. The aims of this work were the alkaloids analysis of a Habranthus cardenasianus bulbs extract, the evaluation of its inhibitory activity against cholinesterases, and to test several propagation strategies for biomass production. Eleven compounds were characterized by GC-MS in the alkaloid extract, which showed a relatively high proportion of tazettine. The known alkaloids tazettine, haemanthamine, and the epimer mixture haemanthidine/6-epi-haemanthidine were isolated and identified by spectroscopic methods. Inhibitory cholinesterases activity was not detected. Three forms of propagation were performed: bulb propagation from seed, cut-induced bulb division, and micropropagated bulbs. Finally, different imbibition and post-collection times were evaluated in seed germination assays. The best propagation method was cut-induced bulb division with longitudinal cuts into quarters (T1) while the best conditions for seed germination were 0-day of post-collection and two days of imbibition. The alkaloids analyses of the H. cardenasianus bulbs showed that they are a source of anti-tumoral alkaloids, especially pretazettine (tazettine) and T1 is a sustainable strategy for its propagation and domestication to produce bioactive alkaloids. Keywords: Amaryllidaceae; bioactive alkaloids; GC-MS; propagation methods; biomass productio

Uso de fitosanitarios naturales en el control ecológico del minador de los cítricos en plantones de mandarino

En este trabajo se compara la eficacia de cuatro productos naturales, tres derivados de plantas (extracto de neem, azadiractina y extracto de ajo), y uno de origen mineral (aceite parafínico), en el control del minador de las hojas de los cítricos, en plantones de mandarinas Beatriz y Orogrande conducidos de forma ecológica. A la vista de los resultados, el control más efectivo fue ejercido por la azadiractina, aunque el resto tenía un comportamiento similar en cuanto a la reducción del daño foliar. Se puede afirmar que cualquiera de los cuatro tratamientos fueron suficientes para controlar la población del insecto, aunque el daño no parece haber reducido la capacidad de crecimiento en los plantones testigo

High-throughput amplicon sequencing-based analysis of active fungal communities inhabiting grapevine after hot-water treatments reveals unexpectedly high fungal diversity

[EN] The ecology of total fungal communities in grapevine is so far largely derived from studies on culture-dependent methods or cultivation-independent rDNA approaches. Sequencing the ribosomal RNA transcripts (rRNA) would rather reveal the functionally and metabolically active important taxa of the fungal community and provide insights into its activity in the wood. The present study investigated changes in the potentially active fungal communities of internal grapevine wood after Hot-Water Treatment (HWT) in planting material from Czech Republic and Spain at two different times during the propagation process and from two plant zones. We examined fungal communities using both traditional isolation into culture and high-throughput amplicon sequencing (HTAS) of the internal transcribed spacer 2 (ITS2) region in extracted total RNA. HTAS from metatranscriptomic RNA increased the resolution of the fungal community analysis and revealed a highly diverse mycobiota of grapevine wood compared to the traditional method. Fungal diversity differed between grapevine genotypes and showed a temporal variation over the vegetative period. Grapevine planting materials exhibited high fungal diversity after HWT, which demonstrates that the HWT process does not sterilize the internal wood of grapevine. HWT reduced the infection caused by fungal trunk disease pathogens but was not completely effective in eliminating their growth. This study provides important and practically useful insights into the dynamics of active fungal communities in hot-water treated plants, and represents the first study of active fungal communities on grapevine grafted plants by comparing traditional and next-generation sequencing methods. (C) 2018 Elsevier Ltd and British Mycological Society. All rights reserved.This work was supported by Projects No. LD14051 from the Ministry of Education, Youth and Sports, Czech Republic covered by COST Action FA1303, and No. CZ.02.1.01/0.0/0.0/16_025/0007314 "Multidisciplinary research to increase application potential of nanomaterials in agricultural practice" from EFRR (Grant provider: Ministerstvo Skolstvi, mladeze a telovychovy Ceske republiky (MSMT). Access to computing and storage facilities owned by parties and projects contributing to the National Grid Infrastructure MetaCentrum provided under the programme "Projects of Large Research, Development, and Innovations Infrastructures" (CESNET LM2015042), is greatly appreciated. David Gramaje was supported by the DOC-INIA program from the National Institute for Agronomic Research (INIA), co-funded by the European Social Fund. The authors are grateful for the technical assistance of Jesus Alfonso Crespo and Aitor Gavara Vidal.Eichmeier, A.; Pecenka, J.; Penazova, E.; Baranek, M.; Català, S.; León Santana, M.; Armengol Fortí, J.... (2018). High-throughput amplicon sequencing-based analysis of active fungal communities inhabiting grapevine after hot-water treatments reveals unexpectedly high fungal diversity. Fungal Ecology. 36:26-38. https://doi.org/10.1016/j.funeco.2018.07.011S26383