Functional characterization of generalized Langevin equations

We present an exact functional formalism to deal with linear Langevin equations with arbitrary memory kernels and driven by any noise structure characterized through its characteristic functional. No others hypothesis are assumed over the noise, neither the fluctuation dissipation theorem. We found that the characteristic functional of the linear process can be expressed in terms of noise's functional and the Green function of the deterministic (memory-like) dissipative dynamics. This object allow us to get a procedure to calculate all the Kolmogorov hierarchy of the non-Markov process. As examples we have characterized through the 1-time probability a noise-induced interplay between the dissipative dynamics and the structure of different noises. Conditions that lead to non-Gaussian statistics and distributions with long tails are analyzed. The introduction of arbitrary fluctuations in fractional Langevin equations have also been pointed out

Composts que es produeixen a Catalunya: caracterització i viabilitat del seu ús com a substrat

A Catalunya es produeixen quantitats considerables de compost. Una de les aplicacions d'aquests productes és la del seu ús en barreges de substrats. Aquest estudi pretén caracteritzar diferents tipologies de compost provinents de diferents plantes de compostatge de Catalunya. Les tipologies que s'han considerat són: el compost de la fracció orgànica dels residus municipals, el compost de residus vegetals de jardineria, el compost d'escorça de pi (o a base d'escorça) i el compost de fems. Se n'han determinat les propietats físiques, fisicoquímiques, químiques i biològiques. Els resultats mostren que les propietats físiques dels diferents materials són prou adequades. Les propietats fisicoquímiques (pH i salinitat) són bastant limitadores per a l'aplicació del compost que es pretén. A més, la composició iònica de l'extracte aquós dels materials és, sovint, desequilibrada pel que fa als macronutrients principals (N, P i K). Els residus vegetals de jardineria compostats amb matèries primeres riques en nitrogen poden ser un material amb possibilitats reals de ser incorporats de manera habitual en barreges per a la preparació de substrats.En Cataluña se producen cantidades considerables de compost. Una de las aplicaciones de estos productos es su uso en mezclas de sustratos. Este estudio tiene como objetivo caracterizar diferentes tipologías de compost de diferentes plantas de compostaje de Cataluña. Las tipologías que se han considerado son: el compost de la fracción orgánica de los residuos municipales, el compost de residuos vegetales de jardinería, el compost de corteza de pino (o a base de este material) y el compost de estiércol. Se han determinado sus propiedades físicas, fisicoquímicas, químicas y biológicas. Los resultados muestran que las propiedades físicas de los diferentes materiales son adecuadas. Las propiedades fisicoquímicas (pH y salinidad) son bastante limitantes para la aplicación que se persigue. Además, la composición iónica del extracto acuoso de los materiales suele ser desequilibrada respecto a los macronutrientes principales (N, P y K). Los residuos vegetales de jardinería compostados con otras materias primas ricas en nitrógeno podrían ser un material con posibilidades reales de ser incorporados de forma habitual en mezclas para la preparación de sustratos.Large amounts of compost are produced in Catalonia. The use of compost in substrate mixtures is a potential use of this material. The main goal of this study is to characterize different kinds of compost produced in composting plants in Catalonia. The following types have been considered: municipal waste organic fraction compost, green waste compost, pine bark compost (or compost based on pine bark) and manure compost. Physical, physico-chemical, chemical and biological properties were examined. Results show that the physical properties of the different materials are appropriate. However, the physico-chemical properties (pH and salinity) showed inadequate values for the specific use of compost as a substrate.Moreover, the ionic composition of the aqueous solution with respect to its main nutrients (N, P and K) is unbalanced. If composted properly with other supplementary materials rich in nitrogen, green waste would be a suitable product to use in substrate mixtures

Minimum Path Cover: The Power of Parameterization

Computing a minimum path cover (MPC) of a directed acyclic graph (DAG) is a fundamental problem with a myriad of applications, including reachability. Although it is known how to solve the problem by a simple reduction to minimum flow, recent theoretical advances exploit this idea to obtain algorithms parameterized by the number of paths of an MPC, known as the width. These results obtain fast [M\"akinen et al., TALG] and even linear time [C\'aceres et al., SODA 2022] algorithms in the small-width regime. In this paper, we present the first publicly available high-performance implementation of state-of-the-art MPC algorithms, including the parameterized approaches. Our experiments on random DAGs show that parameterized algorithms are orders-of-magnitude faster on dense graphs. Additionally, we present new pre-processing heuristics based on transitive edge sparsification. We show that our heuristics improve MPC-solvers by orders-of-magnitude

Beach profile evolution towards equilibrium from varying initial morphologies

The evolution of different initial beach profiles towards the same final beach configuration is investigated based on large-scale experimental data. The same wave condition was performed three times, each time starting from a different initial profile morphology. The three different initial profiles are an intermediate energy profile with an offshore bar and a small swash berm, a plane profile and a low energy profile with a large berm. The three cases evolve towards the same final (equilibrium) profile determined by the same wave condition. This implies that the same wave condition generates different sediment transport patterns. Largest beach changes and differences in hydrodynamics occur in the beginning of the experimental cases, highlighting the coupling between morphology and hydrodynamics for beach evolution towards the same profile. The coupling between morphology and hydrodynamics that leads to the same final beach profile is associated with differences in sediment transport in the surf and swash zone, and is explained by the presence of bar and berm features. A large breaker bar and concave profile promote wave energy dissipation and reduce the magnitudes of the mean near-bed flow velocity close to the shoreline limiting shoreline erosion. In contrast, a beach profile with reflective features, such as a large berm and a small or no bar, increases negative velocity magnitudes at the berm toe promoting shoreline retreat. The findings are summarised in a conceptual model that describes how the beach changes towards equilibrium from two different initial morphologies

Estudio histórico y socio-económico del sector campesino del distrito de Atalaya : de 1970-2000

Objetivos generales: Valorar los elementos geográficos, históricos y socio-culturales que han incidido directa e indirectamente en la situación económica del sector campesino del distrito de Atalaya. Conocer la evolución histórica de las actividades productivas, las formas de organización y los patrones tradicionales del campesino y campesina del distrito de Atalaya en el periodo 1970-2000. Evaluar las políticas y programas estatales ejecutadas en el sector campesino del distrito (1970-2000. Objetivos específicos: Analizar la influencia de las características geográficas y del aspecto social en las actividades realizadas por el campesino, en el distrito de Atalaya. Describir el desarrollo de las actividades productivas y la conformación de los patrones tradicionales de la población de Atalaya. Describir las condiciones socio-económicas de la población campesina, periodo 1970-2000. Analizar los intereses comunes que motivaron a la población campesina de Atalaya a conformar asociaciones de diversos tipos en el periodo (1970-2000)

Bed level motions and sheet flow processes in the swash zone: Observations with a new conductivity-based concentration measuring technique (CCM+)

Detailed measurements of bed level motions and sheet flow processes in the lower swash are presented. The measurements are obtained during a large-scale wave flume experiment focusing on swash zone sediment transport induced by bichromatic waves. A new instrument (CCM+) provides detailed phase-averaged measurements of sheet flow concentrations, particle velocities, and bed level evolution during a complete swash cycle. The bed at the lower swash location shows a clear pattern of rapid erosion during the early uprush and progressive accretion during the middle backwash phase. Sheet flow occurs during the early uprush and mid and late backwash phases. Sheet flow sediment fluxes during these instances are highest in the pick-up layer. Sediment entrainment from the pick-up layer occurs not only during instances of high horizontal shear velocities but also in occurrence of wave–backwash interactions. As opposed to oscillatory sheet flow, the pivot point elevation of the sheet flow layer is time-varying during a swash event. Moreover, the upper sheet flow layer concentrations do not mirror the concentrations in the pick-up layer. Both differences suggest that in the lower swash zone the dynamics of the upper sheet flow layer are not only controlled by vertical sediment exchange (such as in oscillatory sheet flows) but are strongly affected by horizontal advection processes induced by the non-uniformity of the flow

Improving RNA Assembly via Safety and Completeness in Flow Decompositions

Extended version of RECOMB 2022 paperDecomposing a network flow into weighted paths is a problem with numerous applications, ranging from networking, transportation planning, to bioinformatics. In some applications we look for a decomposition that is optimal with respect to some property, such as the number of paths used, robustness to edge deletion, or length of the longest path. However, in many bioinformatic applications, we seek a specific decomposition where the paths correspond to some underlying data that generated the flow. In these cases, no optimization criteria guarantee the identification of the correct decomposition. Therefore, we propose to instead report the safe paths, which are subpaths of at least one path in every flow decomposition. In this work, we give the first local characterization of safe paths for flow decompositions in directed acyclic graphs, leading to a practical algorithm for finding the complete set of safe paths. In addition, we evaluate our algorithm on RNA transcript data sets against a trivial safe algorithm (extended unitigs), the recently proposed safe paths for path covers (TCBB 2021) and the popular heuristic greedy-width. On the one hand, we found that besides maintaining perfect precision, our safe and complete algorithm reports a significantly higher coverage (≈50 compared with the other safe algorithms. On the other hand, the greedy-width algorithm although reporting a better coverage, it also reports a significantly lower precision on complex graphs (for genes expressing a large number of transcripts). Overall, our safe and complete algorithm outperforms (by ≈20 greedy-width on a unified metric (F-score) considering both coverage and precision when the evaluated data set has a significant number of complex graphs. Moreover, it also has a superior time (4−5×) and space performance (1.2−2.2×), resulting in a better and more practical approach for bioinformatic applications of flow decomposition.Peer reviewe

Adolescentes chilenos de estratos sociales superiores con baja competencia lectora

El artículo analiza un fenómeno poco estudiado: la existencia de estudiantes de las capas sociales favorecidas que tienen deficientes resultados de aprendizaje. Se argumenta su interés teórico y se proponen algunos elementos para su comprensión a partir de datos empíricos. Mediante regresiones logísticas, se analizan los factores asociados a los estudiantes chilenos de nivel socio-económico alto que obtuvieron bajos resultados en la prueba de competencia lectora del estudio PISA 2009. El modelo de variables de los estudiantes tuvo mayor poder predictivo que el de las escuelas; se discute hasta qué punto estos resultados dejan entrever la acción de las familias.The article examines a little studied phenomenon: the existence of students from privileged social strata who have poor learning outcomes. We argue their theoretical interest and proposes some elements for understanding from empirical data. Using logistic regression, we analyze the factors associated with Chilean students of high socio-economic status, who scored low on the test of reading achievement from PISA 2009. The model variables of students had greater predictive power than the school. We discuss how these results hint at the action of the families

Implementación de un sistema de escenarios futuros sobre el mapa de usos de suelo de Andalucía.

La Consejería de Medio Ambiente (CMA) ha puesto en marcha un estudio para la generación de cartografía prospectiva de usos de suelo en la Andalucía del siglo XXI. El objeto de este proyecto es explorar y analizar la posible evolución a medio-largo plazo de los usos del suelo y sus implicaciones ambientales, en un contexto de cambio global según diferentes escenarios. Los estudios prospectivos tales como, la construcción de escenarios, permiten iluminar la toma de decisiones. La distribución de los usos de suelo influye en el crecimiento y desarrollo de nuestra sociedad y representa un elemento importante para predecir los impactos ambientales. Actualmente la CMA dispone de una cartografía con los más elevados niveles de detalle y precisión espacial, que cumple los estándares cartográficos internacionales, y que cubre los últimos 50 años en la evolución de los usos del suelo en nuestra región. El poder anticipar, bajo diferentes supuestos de desarrollo socioeconómico, la evolución y la distribución de los usos del suelo en el futuro, supondría avanzar y complementar esta línea de trabajo. La integración de estos factores se ha llevado a cabo mediante autómatas celulares utilizados para modelar los cambios de uso y el desarrollo urbano.The Environmental Ministry of the Andalusian Regional Government has initiated a study to generate prospective mapping of land uses in Andalusia in the XXI century. The goal of this project is to explore and analyze medium to long- term land uses changes and their environmental implications according to different scenarios in the context of global change. Predicting land use change under such scenarios will provide valuable information to decision makers. The distribution of the land uses influences in the growth and development of our society and thus represents a crucial element to predict future environmental impacts. The Environmental Ministry of Andalusia currently has maps available that depict land use changes in the region over the past 50 years and contain the highest level of detail and spatial precision according to international cartographic standards. The power to predict the growth and distribution of future land uses under different assumptions of socioeconomic development will advance and complement this work. The integration of these factors is carried out based on cellular automata applied to model land use changes and urban development

Families of Halo-like invariant tori around L2 in the Earth-Moon Bicircular Problem

The Bicircular Problem (BCP) is a periodic time dependent perturbation of the Earth-Moon Restricted Three-Body Problem that includes the direct gravitational effect of the Sun. In this paper we use the BCP to study the existence of Halo-like orbits around $L_{2}$ in the Earth-Moon system taking into account the perturbation of the Sun. By means of computing families of 2D invariant tori, we show that there are at least two different families of Halo-like quasi-periodic orbits around $L_{2}$