687 research outputs found
Non-parametric Estimation of Stochastic Differential Equations with Sparse Gaussian Processes
The application of Stochastic Differential Equations (SDEs) to the analysis
of temporal data has attracted increasing attention, due to their ability to
describe complex dynamics with physically interpretable equations. In this
paper, we introduce a non-parametric method for estimating the drift and
diffusion terms of SDEs from a densely observed discrete time series. The use
of Gaussian processes as priors permits working directly in a function-space
view and thus the inference takes place directly in this space. To cope with
the computational complexity that requires the use of Gaussian processes, a
sparse Gaussian process approximation is provided. This approximation permits
the efficient computation of predictions for the drift and diffusion terms by
using a distribution over a small subset of pseudo-samples. The proposed method
has been validated using both simulated data and real data from economy and
paleoclimatology. The application of the method to real data demonstrates its
ability to capture the behaviour of complex systems
Sphaerosporella brunnea (Alb. et Schwein.) Svrcek et Kubicka, un discomicete con incidencia en la truficultura e interés forestal
Sphaerosporella brunnea (Alb. et Schwein.) Svrcek et Kubicka, a cup-shaped
ascomycete related with truffle cultures and afforestation. A casual finding of Sphaerosporella brunnea in some greenhouses from Spain, growing in connection with several ectomycorrhizal
plants, is reported. These plants were experimentally inoculated with low level inoculum of Tuber melanosporum. Sphaerosporella brunnea is described and illustrated, and its negative role
in truffle cultures and its possible utilization in burned are as recovery is emphasized.Se da cuenta del hallazgo casual, en unos viveros españoles de Sphaerosporella brunnea, formando micorrizas con plantas diversas, las cuales habían sido inoculadas
experimentalmente con niveles bajos de Tuber melanosporum. Se describe e ilustra esta especie,
al tiempo que se destaca su papel negativo en la truficultura y su posible utilización en la recuperación de áreas incendiadas
Sphaerosporella brunnea (Alb. et Schwein.) Svrcek et Kubicka, un discomicete con incidencia en la truficultura e interés forestal
Se da cuenta del hallazgo casual, en unos viveros españoles de Sphaerosporella brunnea, formando micorrizas con plantas diversas, las cuales habían sido inoculadas
experimentalmente con niveles bajos de Tuber melanosporum. Se describe e ilustra esta especie,
al tiempo que se destaca su papel negativo en la truficultura y su posible utilización en la recuperación de áreas incendiadas.Sphaerosporella brunnea (Alb. et Schwein.) Svrcek et Kubicka, a cup-shaped
ascomycete related with truffle cultures and afforestation. A casual finding of Sphaerosporella brunnea in some greenhouses from Spain, growing in connection with several ectomycorrhizal
plants, is reported. These plants were experimentally inoculated with low level inoculum of Tuber melanosporum. Sphaerosporella brunnea is described and illustrated, and its negative role
in truffle cultures and its possible utilization in burned are as recovery is emphasized
A case of compatibility between quarrying of ornamental granite and forest exploitation
A particular development is proposed to mine some good quality out crops of granite found in a forest exploitation of eucalypts. The exploitation has been designed with a quarrying method, in which small open cast pits are opened and quarried sequentially, and later filled with the waste of the new open pit. Soil is finally used to cover this waste, so new growing tree areas are gaine
Positive and Negative Evidence Accumulation Clustering for Sensor Fusion: An Application to Heartbeat Clustering
In this work, a new clustering algorithm especially geared towards merging data arising from multiple sensors is presented. The algorithm, called PN-EAC, is based on the ensemble clustering paradigm and it introduces the novel concept of negative evidence. PN-EAC combines both positive evidence, to gather information about the elements that should be grouped together in the final partition, and negative evidence, which has information about the elements that should not be grouped together. The algorithm has been validated in the electrocardiographic domain for heartbeat clustering, extracting positive evidence from the heartbeat morphology and negative evidence from the distances between heartbeats. The best result obtained on the MIT-BIH Arrhythmia database yielded an error of 1.44%. In the St. Petersburg Institute of Cardiological Technics 12-Lead Arrhythmia Database database (INCARTDB), an error of 0.601% was obtained when using two electrocardiogram (ECG) leads. When increasing the number of leads to 4, 6, 8, 10 and 12, the algorithm obtains better results (statistically significant) than with the previous number of leads, reaching an error of 0.338%. To the best of our knowledge, this is the first clustering algorithm that is able to process simultaneously any number of ECG leads. Our results support the use of PN-EAC to combine different sources of information and the value of the negative evidenceThis research was funded by the Ministry of Science, Innovation and Universities of Spain, and the European Regional Development Fund of the European Commission, Grant Nos. RTI2018-095324-B-I00, RTI2018-097122-A-I00, and RTI2018-099646-B-I00S
The AMIGA sample of isolated galaxies. IV. A catalogue of neighbours around isolated galaxies
Studies of the effects of environment on galaxy properties and evolution
require well defined control samples. Such isolated galaxy samples have up to
now been small or poorly defined. The AMIGA project (Analysis of the
interstellar Medium of Isolated GAlaxies) represents an attempt to define a
statistically useful sample of the most isolated galaxies in the local (z <
0.05) Universe. A suitable large sample for the AMIGA project already exists,
the Catalogue of Isolated Galaxies (CIG, Karachentseva 1973; 1050 galaxies),
and we use this sample as a starting point to refine and perform a better
quantification of its isolation properties. Digitised POSS-I E images were
analysed out to a minimum projected radius R > 0.5 Mpc around 950 CIG galaxies
(those within Vr = 1500 km s-1 were excluded). We identified all galaxy
candidates in each field brighter than B = 17.5 with a high degree of
confidence using the LMORPHO software. We generated a catalogue of
approximately 54 000 potential neighbours (redshifts exist for 30% of this
sample). Six hundred sixty-six galaxies pass and two hundred eighty-four fail
the original CIG isolation criterion. The available redshift data confirm that
our catalogue involves a largely background population rather than physically
associated neighbours. We find that the exclusion of neighbours within a factor
of four in size around each CIG galaxy, employed in the original isolation
criterion, corresponds to Delta Vr ~ 18000 km s-1 indicating that it was a
conservative limit. Galaxies in the CIG have been found to show different
degrees of isolation. We conclude that a quantitative measure of this is
mandatory. It will be the subject of future work based on the catalogue of
neighbours obtained here.Comment: Accepted by A&A, 10 pages, 8 figures, 4 table
DISEÑO E IMPLEMENTACIÓN DE UN HEXÁPODO ROBÓTICO EMPLEANDO EL DRIVER “INTECMX14” PARA EL CONTROL PARALELO DE MOTORES
ResumenLos robots móviles por sus características requieren de estructuras estables y sistemas de control con las capacidades para lograr movimientos fluidos o naturales, proyecto propone un hexápodo con tres grados de libertad construido a base del uso de nylalloy como material principal, utilizando 18 servomotores distribuidos en juegos 3 por cada extremidad, con uso de una tarjeta FPGA atlys para el desarrollo de una programación paralela dentro de 4 rutinas de movimiento diferentes cuyas posiciones fueron calculadas por el método de cinemática de Denavit-Hartenberg y el método inverso haciendo uso de matrices Homogénea.Palabras clave: Denavit-Hartenberg, Hexápodo, Robot móvil. DESIGN AND IMPLEMENTATION OF A ROBOTIC HEXAPOD USING THE "INTECMX14" DRIVER FOR PARALLEL MOTOR CONTROL AbstractMobile robots by their characteristics require stable structures and control systems with the capabilities to achieve fluid or natural movements, proposes a game with three degrees of freedom built using nylalloy as the main material, using 18 servomotors distributed in games 3 for each tip, using an atlys FPGA card for the development of parallel programming within 4 different motion routines whose positions were calculated by the Denavit-Hartenberg direct kinematics method and the inverse method with the use of homogeneous matrix.Keywords: Denavit-Hartenberg, Hexapod, mobile robot
A gliclazide complex based on palladium towards Alzheimer's disease: Promising protective activity against Aβ-induced toxicity in: C. elegans
A new palladium coordination compound based on gliclazide with the chemical formula [Pd(glz)2] (where glz = gliclazide) has been synthesized and characterised. The structural characterization reveals that this material consists of mononuclear units formed by a Pd2+ ion coordinated to two molecules of the glz ligand, in which palladium ions exhibit a distorted plane-square coordination sphere. This novel material behaves like a good and selective inhibitor of butyrylcholinesterase, one of the most relevant therapeutic targets against Alzheimer's disease. Analysis of the enzyme kinetics showed a mixed mode of inhibition, the title compound being capable of interacting with both the free enzyme and the enzyme-substrate complex. Finally, the palladium compound shows promising protective activity against Aβ-induced toxicity in the Caenorhabditis elegans model, which has never been reported.he authors gratefully acknowledge funding support from the Spanish Ministry of Science, Innovation and Universities (PGC2018-102052-B-C21 and PID2020-116460RB-I00) and the Junta de Andalućıa (FQM-394 and FQM-134). The authors gratefully acknowledge the funding support of FEDER/Junta de Andalućıa Consejería de Economía y Conocimiento, Grant B-AGR-193-UGR18. O. L. and J. G. F. B. also thank Grant PID2020-116460RB-I00 funded by MCIN/AEI/10.13039/50110 0011033. S. R. acknowledge the Juan de la Cierva Fellowship (IJC2019-038894-I)
- …