4,076 research outputs found

    Testing statics-dynamics equivalence at the spin-glass transition in three dimensions

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    The statics-dynamics correspondence in spin glasses relate non-equilibrium results on large samples (the experimental realm) with equilibrium quantities computed on small systems (the typical arena for theoretical computations). Here we employ statics-dynamics equivalence to study the Ising spin-glass critical behavior in three dimensions. By means of Monte Carlo simulation, we follow the growth of the coherence length (the size of the glassy domains), on lattices too large to be thermalized. Thanks to the large coherence lengths we reach, we are able to obtain accurate results in excellent agreement with the best available equilibrium computations. To do so, we need to clarify the several physical meanings of the dynamic exponent close to the critical temperature.Comment: Version to appear in Physical Review

    Deep learning phase picking of large-N experiments

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    The popularisation of the use of large-N arrays of seismometers has resulted in a significant increase of the size of the datasets recorded during these experiments. Therefore, new challenges have arisen on how to process all these data efficiently, and in an automated fashion. This is particularly true in the case of induced seismicity monitoring, where often a large number of number of events are recorded at high frequency sampling rates. Several methods of automatic picking have been developed during recent years, from triggering algorithms (e.g. STA/LTA) to higher order statistics or waveform similarity. Latest development in computational power and the popularization of GPUs have made possible to apply machine learning methods to several problems, from arrival picking and phase detection to earthquake location. We have developed a deep neural network to detect the arrivals of seismic body waves, using an architecture based on convolutional layers. This type of models are widely used in computer vision applications, which is the most similar case to the phase picking by an operator. Trained with the data of the Southern California Seismic Network, this network is able to differentiate P and S waves from background noise with a precision higher than 98%. We have applied this neural network to other large-N experiments in other regions (Europe and Asia) and found that the network localizes the events with a precision comparable or superior to an human operator, even in the case of low signal-noise ratio and superposition of earthquakes.This research has been funded by MICINN Project CGL2017-88864-

    Application of Deadlock Risk Evaluation of Architectural Models

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    Software architectural evaluation is a key discipline used to identify, at early stages of a real-time system (RTS) development, the problems that may arise during its operation. Typical mechanisms supporting concurrency, such as semaphores, mutexes or monitors, usually lead to concurrency problems in execution time that are difficult to be identified, reproduced and solved. For this reason, it is crucial to understand the root causes of these problems and to provide support to identify and mitigate them at early stages of the system lifecycle. This paper aims to present the results of a research work oriented to the development of the tool called ‘Deadlock Risk Evaluation of Architectural Models’ (DREAM) to assess deadlock risk in architectural models of an RTS. A particular architectural style, Pipelines of Processes in Object-Oriented Architectures–UML (PPOOA) was used to represent platform-independent models of an RTS architecture supported by the PPOOA –Visio tool. We validated the technique presented here by using several case studies related to RTS development and comparing our results with those from other deadlock detection approaches, supported by different tools. Here we present two of these case studies, one related to avionics and the other to planetary exploration robotics. Copyright © 2011 John Wiley & Sons, Ltd

    Applying Deadlock Risk Assessment in Architectural Models of Real-Time Systems

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    Software Architectural Assessment is a key discipline to identify at early stages of a real-time system (RTS) synthesis the problems that may become critical in its operation. Typical mechanisms supporting concurrency, such as semaphores or monitors, usually lead to concurrency problems in execution time difficult to identify, reproduce and solve. For this reason it is crucial to understand the root causes of these problems and to provide support to identify and mitigate them at early stages of the system lifecycle. This paper aims to present the results of a research work oriented to the creation of a tool to assess deadlock risk in architectural models of a RTS. A concrete architectural style (PPOOA-UML) was used to represent PIM (Platform Independent Models) of a RTS architecture supported by the PPOOA-Visio CASE tool. A case study was used to validate the deadlock assessment tool created. In the context of one of the functions of a military transport aircraft, the auto-tuning function of the communications system was selected for the assessment of the deadlock risk. According to the results obtained some guidelines are outlined to minimize the deadlock risk of the system architecture

    Distribución y Aspectos Poblacionales del Lobo Ibérico en la Provincia de Ourense / Distribution and Population Aspects of the Iberian Wolf in the Province of Ourense, Spain

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    Para determinar el área de distribución del lobo en la provincia de Ourense (noroeste de España) se realizaron prospecciones de campo consistentes en itinerarios de muestreo para localizar indicios y se enviaron cuestionarios a los Agentes del Servicio de Conservación de la Naturaleza de la Xunta de Galicia y a las Sociedades de Cazadores del área de estudio. Los resultados se registraron sobre cuadrículas U.T.M. 10x10 Km. Se constata presencia del lobo en el 79,2% de las cuadrículas estudiadas, estimando el área de distribución en la provincia en 6.400 km2. Para la localización de los grupos familiares inicialmente se prospectó el territorio a nivel de cuadrículas U.T.M. 10x10 Km y en función de los resultados y la información recibida se eligieron determinadas zonas para realizar estaciones de escucha y espera. Determinamos durante el periodo de estudio la existencia de 25 grupos familiares. La densidad estimada en la provincia es de 2,10 – 3,28 lobos /100 km2. De los casos de mortalidad conocidos entre enero de 1999 y abril de 2002 (n=37), un elevado porcentaje se debió a atropellos (70,27%) principalmente en dos vías concretas y un 8,10% correspondió a envenenamientos. Actualmente la densidad del lobo en Ourense es superior a la obtenida en provincias limítrofes, pero amenazas de origen antrópico tanto directas (veneno, persecución ilegal...) como indirectas (incendios forestales, grandes infraestructuras viales, parques eólicos...) pueden estar condicionando la existencia de grupos familiares e incluso la presencia de la especie en determinadas zonas

    Soil moisture increment as a controlling variable of the Birch effect . Interactions with the pre-wetting soil moisture and litter addition

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    The Birch effect is a pulse in soil C and N mineralization caused by the wetting of dry soils, but the role of the soil moisture increment (Delta SWC) is still poorly understood. We quantified the relationship between Delta SWC and the Birch effect, and its interactions with pre-wetting soil moisture (preSWC) and substrate supply. Two soils (clay loam and sandy loam) under a Pinus halepensis forest were subjected to rewetting in laboratory treatments combining different Delta SWC and preSWC values, with or without additional substrate (5 mg g(-1) P. halepensis needles). Respiration flush (Delta R), changes in microbial biomass C (MBC) and net N mineralization (NMIN) were measured. Overall, we found a relationship with the form: Delta R = a Delta SWC + b, where the slope (a) was significant only when pre-wetting water potential was below a threshold value in the range of -100 to -1,200 kPa. However, the threshold alone does not fully describe the role of preSWC in slope variability. Substrate addition modified the Delta SWC sensitivity of Birch effect, enhancing it in the clay loam and suppressing it in the sandy loam. The intensity of the wetting is a dominant factor regulating Birch effect, and Delta SWC is useful for its quantification.This work was supported by a fellowship from Generalitat Valenciana, Conselleria de Educacion, Formacion y Empleo awarded to L. Lado-Monserrat (BFPI/2008/041). Thanks are due to Antonio del Campo for help in data analyses and to Antonio Lloret for laboratory work. The authors wish to thank Joana Oliver for invaluable laboratory support. The authors also thank two anonymous reviewers and Professor Stephan Glatzel from the University of Rostock, Germany, for the critical review of the manuscript.Lado Monserrat, L.; Lull Noguera, C.; Bautista Carrascosa, MI.; Lidón Cerezuela, AL.; Herrera Fernandez, R. (2014). Soil moisture increment as a controlling variable of the Birch effect . Interactions with the pre-wetting soil moisture and litter addition. Plant and Soil. 379(1-2):21-34. https://doi.org/10.1007/s11104-014-2037-5S21343791-2Austin AT, Yahdjian L, Stark JM, Belnap J, Porporato A, Norton U, Ravetta DA, Schaeffer SM (2004) Water pulses and biogeochemical cycles in arid and semiarid ecosystems. Oecologia 141:221–235Berryman E, Marshall JD, Rahn T, Litvak M, Butnor J (2013) Decreased carbon limitation of litter respiration in a mortality-affected piñon-juniper woodland. Biogeosciences 10:1625–1634Birch HF (1958) The effect of soil drying on humus decomposition and nitrogen. Plant soil 10:9–31Borken W, Matzner E (2009) Reappraisal of drying and wetting effects on C and N mineralization and fluxes in soils. Global Change Biol 15:808–824Bottner P (1985) Response of microbial biomass to alternate moist and dry conditions in a soil incubated with C-14-labeled and N-15-labeled plant material. Soil Biol Biochem 17:329–337Butterly CR, Bünemann EK, McNeill AM, Baldock JA, Marschner P (2009) Carbon pulses but not phosphorus pulses are related to decreases in microbial biomass during repeated drying and rewetting of soils. Soil Biol Biochem 41:1406–1416Cable JM, Ogle K, Williams DG, Weltzin JF, Huxman TE (2008) Soil texture drives responses of soil respiration to precipitation pulses in the Sonoran Desert: implications for climate change. Ecosystems 11:961–979Campbell GS (1974) A simple method for determining unsaturated conductivity from moisture retention data. Soil Sci 117:311–314Carbone MS, Still CJ, Ambrose AR, Dawson TE, Williams AP, Boot CM, Schaeffer SM, Schimel JP (2011) Seasonal and episodic moisture controls on plant and microbial contributions to soil respiration. Oecologia 167:265–278Chatterjee A, Jenerette GD (2011) Changes in soil respiration Q10 during drying-rewetting along a semi-arid elevation gradient. Geoderma 163:171–177Chowdhury N, Burns RG, Marschner P (2011a) Recovery of soil respiration after drying. Plant Soil 348:269–279Chowdhury N, Nakatani AS, Setia R, Marschner P (2011b) Microbial activity and community composition in saline and non-saline soils exposed to multiple drying and rewetting events. Plant Soil 348:103–113Cobos D, Campbell C (2007) Correcting temperature sensitivity of ECH2O soil moisture sensors. Application note. Decagon Devices Inc., PullmanDaly E, Palmroth S, Stoy P, Siqueira M, Oishi AC, Juang JY, Oren R, Porporato A, Katul GG (2009) The effects of elevated atmospheric CO2 and nitrogen amendments on subsurface CO2 production and concentration dynamics in a maturing pine forest. Biogeochemistry 94:271–287Denef K, Six J, Bossuyt H, Frey SD, Elliott ET, Merckx R, Paustian K (2001) Influence of dry-wet cycles on the interrelationship between aggregate, particulate organic matter, and microbial community dynamics. Soil Biol Biochem 33:1599–1611Fernandez C, Lelong B, Vila B, Mévy JP, Robles C, Greff S, Dupouyet S, Bousquet-Mélou A (2006) Potential allelopathic effect of Pinus halepensis in the secondary succession: an experimental approach. Chemoecology 16:97–105Fierer N, Schimel JP (2002) Effects of drying-rewetting frequency on soil carbon and nitrogen transformations. Soil Biol Biochem 34:777–787Fischer T (2009) Substantial rewetting phenomena on soil respiration can be observed at low water availability. Soil Biol Biochem 41:1577–1579Franzluebbers AJ, Haney RL, Honeycutt CW, Schomberg HH, Hons FM (2000) Flush of carbon dioxide following rewetting of dried soils relates to active organic pools. Soil Sci Soc Am J 64:613–623García-Plé C, Vanrell P, Morey M (1995) Litter fall and decomposition in a Pinus halepensis forest on Mallorca. J Veg Sci 6:17–22GVA (1995) Mapa de Suelos de la Comunidad Valenciana. Chelva (666). Proyecto LUCDEME (Icona), Centro de Investigaciones sobre Desertificación y Conselleria d’Agricultura i Mig Ambient. Generalitat Valenciana. Valencia, Spain. (Original in Spanish).Halverson LJ, Jones TM, Firestone MK (2000) Release of intracellular solutes by four soil bacteria exposed to dilution stress. Soil Sci Soc Am J 64:1630–1637Harrison-Kirk T, Beare MH, Meenken ED, Condron LM (2013) Soil organic matter and texture affect responses to dry/wet cycles: Effects on carbon dioxide and nitrous oxide emissions. Soil Biol Biochem 57:43–55Harris RF (1981) Effect of water potential on microbial growth and activity. In: Parr JF, Gardner WR, Elliott LF (eds) Water potential relations in soil microbiology. Am Soc Agron, Madison, pp 23–95Haynes RJ, Swift RS (1990) Stability of soil aggregates in relation to organic constituents and soil water content. J Soil Sci 41:73–83Jarvis P, Rey A, Petsikos C, Wingate L, Rayment M, Pereira J, Banza J, David J, Miglietta F, Borghetti M, Manca G, Valentini R (2007) Drying and wetting of Mediterranean soils stimulates decomposition and carbon dioxide emission: the “Birch effect”. Tree Physiol 27:929–940Kieft TL, Soroker E, Firestone MK (1987) Microbial biomass response to a rapid increase in water potential when dry soil is wetted. Soil Biol Biochem 19:119–126Kim D, Mu S, Kang S, Lee D (2010) Factors controlling soil CO2 effluxes and the effects of rewetting on effluxes in adjacent deciduous, coniferous, and mixed forests in Korea. Soil Biol Biochem 42:576–585Manzoni S, Schimel JP, Porporato A (2012) Responses of soil microbial communities to water stress: results from a meta-analysis. Ecology 93:930–938McIntyre RES, Adams MA, Ford DJ, Grierson PF (2009) Rewetting and litter addition influence mineralisation and microbial communities in soils from a semi-arid intermittent stream. Soil Biol Biochem 41:92–101Miller AE, Schimel JP, Meixner T, Sickman JO, Melack JM (2005) Episodic rewetting enhances carbon and nitrogen release from chaparral soils. Soil Biol Biochem 37:2195–2204Muhr J, Franke J, Borken W (2010) Drying-rewetting events reduce C and N losses from a Norway spruce forest floor. Soil Biol Biochem 42:1303–1312Navarro-García F, Casermeiro MA, Schimel JP (2012) When structure means conservation: Effect of aggregate structure in controlling microbial responses to rewetting events. Soil Biol Biochem 44:1–8Rey A, Petsikos C, Jarvis PG, Grace J (2005) Effect of temperature and moisture on rates of carbon mineralization in a Mediterranean oak forest soil under controlled and field conditions. Eur J Soil Sci 56:589–599Richards LA (1965) Physical condition of water in soil. In: Black CA, Evans DD, White JL, Ensminger LE, Clark FE (eds) Methods of soil analysis part 1. Agronomy series n°9. American Society of Agronomy, MadisonScanlon BR, Andraski BJ, Bilskie J (2002) Miscellaneous methods for measuring matric or water potential. In: Dane JH, Topp GC (Eds) Methods of Soil Analysis. Part 4: Physical Methods. Soil Sci Soc Am, Madison. Wisconsin, pp: 643–670.Schmitt A, Glaser B, Borken W, Martzner E (2010) Organic matter quality of a forest soil subjected to repeated drying and different re-wetting intensities. Eur J Soil Sci 61:243–254Sponseller RA (2007) Precipitation pulses and soil CO2 flux in a Sonoran Desert ecosystem. Global Change Biol 13:426–436Unger S, Máguas C, Pereira JS, David TS, Werner C (2010) The influence of precipitation pulses on soil respiration – Assessing the “Birch effect” by stable carbon isotopes. Soil Biol Biochem 42:1800–1810Vance ED, Brookes PC, Jenkinson DS (1987) Microbial biomass measurements in forest soils: The use of the chloroform fumigation-incubation method in strongly acid soils. Soil Biol Biochem 19:697–702Van Gestel M, Merckx R, Vlassak K (1993) Microbial biomass responses to soil drying and rewetting – the fate of fast-growing and slow-growing microorganisms in soils from different climates. Soil Biol Biochem 25:109–123Wu J, Joergensen RG, Pommerening B, Chaussod R, Brookes PC (1990) Measurement of soil microbial biomass C by fumigation-extraction - an automated procedure. Soil Biol Biochem 22:1167–1169Wu H, Lee X (2011) Short-term effects of rain on soil respiration in two New England forests. Plant Soil 338:329–342Xiang SR, Doyle A, Holden PA, Schimel JP (2008) Drying and rewetting effects on C and N mineralization and microbial activity in surface and subsurface California grassland soils. Soil Biol Biochem 40:2281–2289Xu LK, Baldocchi DD, Tang JW (2004) How soil moisture, rain pulses, and growth alter the response of ecosystem respiration to temperature. Global Biogeochem Cyc 18, GB4002. doi: 10.1029/2004GB002281Xu X, Luo X (2012) Effect of wetting intensity on soil GHG fluxes and microbial biomass under a temperate forest floor during dry season. Geoderma 170:118–126Yuste JC, Janssens IA, Ceulemans R (2005) Calibration and validation of an empirical approach to model soil CO2 efflux in a deciduous forest. Biogeochemistry 73:209–23

    Maximum equilibrium prevalence of mosquito-borne microparasite infections in humans.

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    To determine the maximum equilibrium prevalence of mosquito-borne microparasitic infections, this paper proposes a general model for vector-borne infections which is flexible enough to comprise the dynamics of a great number of the known diseases transmitted by arthropods. From equilibrium analysis, we determined the number of infected vectors as an explicit function of the model's parameters and the prevalence of infection in the hosts. From the analysis, it is also possible to derive the basic reproduction number and the equilibrium force of infection as a function of those parameters and variables. From the force of infection, we were able to conclude that, depending on the disease's structure and the model's parameters, there is a maximum value of equilibrium prevalence for each of the mosquito-borne microparasitic infections. The analysis is exemplified by the cases of malaria and dengue fever. With the values of the parameters chosen to illustrate those calculations, the maximum equilibrium prevalence found was 31% and 0.02% for malaria and dengue, respectively. The equilibrium analysis demonstrated that there is a maximum prevalence for the mosquito-borne microparasitic infections
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