9,742 research outputs found
Seasonal dynamic factor analysis and bootstrap inference : application to electricity market forecasting
Year-ahead forecasting of electricity prices is an important issue in the current context of electricity markets. Nevertheless, only one-day-ahead forecasting is commonly tackled up in previous published works. Moreover, methodology developed for the short-term does not work properly for long-term forecasting. In this paper we provide a seasonal extension of the Non-Stationary Dynamic Factor Analysis, to deal with the interesting problem (both from the economic and engineering point of view) of long term forecasting of electricity prices. Seasonal Dynamic Factor Analysis (SeaDFA) allows to deal with dimensionality reduction in vectors of time series, in such a way that extracts common and specific components. Furthermore, common factors are able to capture not only regular dynamics (stationary or not) but also seasonal one, by means of common factors following a multiplicative seasonal VARIMA(p,d,q)×(P,D,Q)s model. Besides, a bootstrap procedure is proposed to be able to make inference on all the parameters involved in the model. A bootstrap scheme developed for forecasting includes uncertainty due to parameter estimation, allowing to enhance the coverage of forecast confidence intervals. Concerning the innovative and challenging application provided, bootstrap procedure developed allows to calculate not only point forecasts but also forecasting intervals for electricity prices.Dynamic factor analysis, Bootstrap, Forecasting, Confidence intervals
Revealing a geographical distribution of several strains of Coconut Lethal Yellowing phytoplasmas associated with different patterns of dispersal in Cuba
An exponential chemorheological model for viscosity dependence on degree-of-cure of a polyfurfuryl alcohol resin during the post-gel curing stage
Situation actuelle des hémoparasitoses bovines en Martinique (Antilles françaises)
Une enquête sérologique par immunofluorescence indirecte pour les babésioses bovines (Babesia bovis et B. bigemina) et par agglutination pour l'anaplasmose bovine, indique que ces hémoparasitoses sont largement répandues en Martinique. Les séroprévalences élevées (62 p. 100 pour B. bovis, 52 p. 100 pour B. bigemina et 43 p. 100 pour Anaplasma marginale) font penser à une situation épizootiologique instable pour ces trois hémoparasitoses mais le faible nombre de frottis observés ne permet pas d'apprécier leur incidence clinique. Les deux Card tests américain et cubain donnent des résultats pratiquement identiques dans la détection d'anticorps anti-A. marginale. Theileria mutans est signalé pour la première fois en Martinique. Quant à la trypanosomose à Trypanosoma vivax, elle a disparu de l'île cliniquement et sérologiquemen
The Infrared Astronomical Characteristics of Roque de los Muchachos Observatory: precipitable water vapor statistics
The atmospheric water vapor content above the Roque de los Muchachos
Observatory (ORM) obtained from Global Positioning Systems (GPS) is presented.
GPS measurements have been evaluated by comparison with 940nm-radiometer
observations. Statistical analysis of GPS measurements points to ORM as an
observing site with suitable conditions for infrared (IR) observations, with a
median column of precipitable water vapor (PWV) of 3.8 mm. PWV presents a clear
seasonal behavior, being Winter and Spring the best seasons for IR
observations. The percentage of nighttime showing PWV values smaller than 3 mm
is over 60% in February, March and April. We have also estimated the temporal
variability of water vapor content at the ORM. A summary of PWV statistical
results at different astronomical sites is presented, recalling that these
values are not directly comparable as a result of the differences in the
techniques used to recorded the data.Comment: The paper contains 10 figures and 5 tables (28 pages) Accepted by
MNRA
Confirmation of an exoplanet using the transit color signature: Kepler-418b, a blended giant planet in a multiplanet system
We announce confirmation of Kepler-418b, one of two proposed planets in this
system. This is the first confirmation of an exoplanet based primarily on the
transit color signature technique. We used the Kepler public data archive
combined with multicolor photometry from the Gran Telescopio de Canarias and
radial velocity follow-up using FIES at the Nordic Optical Telescope for
confirmation. We report a confident detection of a transit color signature that
can only be explained by a compact occulting body, entirely ruling out a
contaminating eclipsing binary, a hierarchical triple, or a grazing eclipsing
binary. Those findings are corroborated by our radial velocity measurements,
which put an upper limit of ~1 Mjup on the mass of Kepler-418b. We also report
that the host star is significantly blended, confirming the ~10% light
contamination suspected from the crowding metric in the Kepler light curve
measured by the Kepler team. We report detection of an unresolved light source
that contributes an additional ~40% to the target star, which would not have
been detected without multicolor photometric analysis. The resulting
planet-star radius ratio is 0.110 +/- 0.0025, more than 25% more than the 0.087
measured by Kepler, leading to a radius of 1.20 +/- 0.16 Rjup instead of the
0.94 Rjup measured by the Kepler team. This is the first confirmation of an
exoplanet candidate based primarily on the transit color signature,
demonstrating that this technique is viable from ground for giant planets. It
is particularly useful for planets with long periods such as Kepler-418b, which
tend to have long transit durations. Additionally, multicolor photometric
analysis of transits can reveal unknown stellar neighbors and binary companions
that do not affect the classification of the transiting object but can have a
very significant effect on the perceived planetary radius.Comment: accepted by Astronomy & Astrophysic
How Prosecutors and Defense Attorneys Differ in Their Use of Neuroscience Evidence
Much of the public debate surrounding the intersection of neuroscience and criminal law is based on assumptions about how prosecutors and defense attorneys differ in their use of neuroscience evidence. For example, according to some commentators, the defense’s use of neuroscience evidence will abdicate criminals of all responsibility for their offenses. In contrast, the prosecution’s use of that same evidence will unfairly punish the most vulnerable defendants as unfixable future dangers to society. This “double- edged sword” view of neuroscience evidence is important for flagging concerns about the law’s construction of criminal responsibility and punishment: it demonstrates that the same information about the defendant can either be mitigating or aggravating depending on who is raising it. Yet empirical assessments of legal decisions reveal a far more nuanced reality, showing that public beliefs about the impact of neuroscience on the criminal law can often be wrong. This Article takes an evidence-based and multidisciplinary approach to examining how courts respond to neuroscience evidence in capital cases when the defense presents it to argue that the defendant’s mental state at the time of the crime was below the given legal requisite due to some neurologic or cognitive deficiency
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