HIGH PRICE VOLATILITY AND SPILLOVER EFFECTS IN ENERGY MARKETS

Replaced with revised version of paper 07/22/11.Asymmetric shocks, energy markets, oil, spillover effects, volatility, Marketing, Resource /Energy Economics and Policy, GARCH,

Classifying continuous, real-time e-nose sensor data using a bio-inspired spiking network modelled on the insect olfactory system

In many application domains, conventional e-noses are frequently outperformed in both speed and accuracy by their biological counterparts. Exploring potential bio-inspired improvements, we note a number of neuronal network models have demonstrated some success in classifying static datasets by abstracting the insect olfactory system. However, these designs remain largely unproven in practical settings, where sensor data is real-time, continuous, potentially noisy, lacks a precise onset signal and accurate classification requires the inclusion of temporal aspects into the feature set. This investigation therefore seeks to inform and develop the potential and suitability of biomimetic classifiers for use with typical real-world sensor data. Taking a generic classifier design inspired by the inhibition and competition in the insect antennal lobe, we apply it to identifying 20 individual chemical odours from the timeseries of responses of metal oxide sensors. We show that four out of twelve available sensors and the first 30 s(10%) of the sensors’ continuous response are sufficient to deliver 92% accurate classification without access to an odour onset signal. In contrast to previous approaches, once training is complete, sensor signals can be fed continuously into the classifier without requiring discretization. We conclude that for continuous data there may be a conceptual advantage in using spiking networks, in particular where time is an essential component of computation. Classification was achieved in real time using a GPU-accelerated spiking neural network simulator developed in our group

Measurement of the neutron electric dipole moment via spin rotation in a non-centrosymmetric crystal

We have measured the neutron electric dipole moment using spin rotation in a non-centrosymmetric crystal. Our result is d_n = (2.5 +- 6.5(stat) +- 5.5(syst)) 10^{-24} e cm. The dominating contribution to the systematic uncertainty is statistical in nature and will reduce with improved statistics. The statistical sensitivity can be increased to 2 10^{-26} e cm in 100 days data taking with an improved setup. We state technical requirements for a systematic uncertainty at the same level.Comment: submitted to Phys. Lett.

Strong HI Lyman-α\alpha variations from the 11 Gyr-old host star Kepler-444: a planetary origin ?

Kepler-444 provides a unique opportunity to probe the atmospheric composition and evolution of a compact system of exoplanets smaller than the Earth. Five planets transit this bright K star at close orbital distances, but they are too small for their putative lower atmosphere to be probed at optical/infrared wavelengths. We used the Space Telescope Imaging Spectrograph instrument onboard the Hubble Space Telescope to search for the signature of the planet's upper atmospheres at six independent epochs in the Ly-$\alpha$ line. We detect significant flux variations during the transits of both Kepler-444e and f (~20%), and also at a time when none of the known planets was transiting (~40%). Variability in the transition region and corona of the host star might be the source of these variations. Yet, their amplitude over short time scales (~2-3 hours) is surprisingly strong for this old (11.2+-1.0Gyr) and apparently quiet main-sequence star. Alternatively, we show that the in-transits variations could be explained by absorption from neutral hydrogen exospheres trailing the two outer planets (Kepler-444e and f). They would have to contain substantial amounts of water to replenish such hydrogen exospheres, which would reveal them as the first confirmed ocean-planets. The out-of-transit variations, however, would require the presence of a yet-undetected Kepler-444g at larger orbital distance, casting doubt on the planetary origin scenario. Using HARPS-N observations in the sodium doublet, we derived the properties of two Interstellar Medium clouds along the line-of-sight toward Kepler-444. This allowed us to reconstruct the stellar Ly-$\alpha$ line profile and to estimate the XUV irradiation from the star, which would still allow for a moderate mass loss from the outer planets after 11.2Gyr. Follow-up of the system at XUV wavelengths will be required to assess this tantalizing possibility.Comment: Accepted for publication in A&A Name of the system added to the title in most recent versio

The long egress of GJ~436b's giant exosphere

The M dwarf GJ 436 hosts a transiting warm Neptune known to experience atmospheric escape. Previous observations revealed the presence of a giant hydrogen exosphere transiting the star for more than 5 h, and absorbing up to 56% of the flux in the blue wing of the stellar Lyman-{\alpha} line of neutral hydrogen (H i Ly{\alpha}). The unexpected size of this comet-like exosphere prevented observing the full transit of its tail. In this Letter, we present new Ly{\alpha} observations of GJ 436 obtained with the Space Telescope Imaging Spectrograph (STIS) instrument onboard the Hubble Space Telescope. The stability of the Ly{\alpha} line over six years allowed us to combine these new observations with archival data sets, substantially expanding the coverage of the exospheric transit. Hydrogen atoms in the tail of the exospheric cloud keep occulting the star for 10-25 h after the transit of the planet, remarkably confirming a previous prediction based on 3D numerical simulations with the EVaporating Exoplanet code (EVE). This result strengthens the interpretation that the exosphere of GJ 436b is shaped by both radiative braking and charge exchanges with the stellar wind. We further report flux decreases of 15 +/- 2% and 47 +/- 10% in the red wing of the Ly{\alpha} line and in the line of ionised silicon (Si iii). Despite some temporal variability possibly linked with stellar activity, these two signals occur during the exospheric transit and could be of planetary origin. Follow-up observations will be required to assess the possibility that the redshifted Ly{\alpha} and Si iii absorption signatures arise from interactions between the exospheric flow and the magnetic field of the star.Comment: 10 pages, 7 figures, published in A&

Impact of hypnosis on psychophysiological measures: A scoping literature review.

Exploring psychophysiological changes during hypnosis can help to better understand the nature and extent of the hypnotic phenomenon by characterizing its influence on the autonomic nervous system (ANS), in addition to its central brain effects. Hypnosis is thought to induce a relaxation response, yet studies using objective psychophysiological measures alongside hypnosis protocols show various results. We review this literature and clarify the effects of hypnosis on psychophysiological indices of ANS activity and more specifically of the stress/relaxation response, such as heart rate variability and electrodermal activity. Studies reporting psychophysical measures during hypnosis were identified by a series of Pubmed searches. Data was extracted with an interest for the influence of hypnotizability and effects of specific suggestions or tasks on the findings. We found 49 studies comprising 1315 participants, 45 concerning healthy volunteers and only 4 on patients. Sixteen compared high vs. low hypnotizable people; 30 measured heart rate, 18 measured heart rate variability, 25 electrodermal activity, and 23 respiratory signals as well as other physiological parameters. Globally, results converge to show reductions in sympathetic responses and/or increases in parasympathetic tone under hypnosis. Several methodological limitations are underscored, such as older studies (N = 16) using manual analyses, small sample sizes (<30, N = 31), as well as uncontrolled multiple comparisons. Nevertheless, we confirm that hypnosis leads to a physiological relaxation response and highlight promising avenues for this research. Suggestions are made for guiding future work in this field

Magnetic Fluctuations and Correlations in MnSi - Evidence for a Skyrmion Spin Liquid Phase

We present a comprehensive analysis of high resolution neutron scattering data involving Neutron Spin Echo spectroscopy and Spherical Polarimetry which confirm the first order nature of the helical transition and reveal the existence of a new spin liquid skyrmion phase. Similar to the blue phases of liquid crystals this phase appears in a very narrow temperature range between the low temperature helical and the high temperature paramagnetic phases.Comment: 11 pages, 16 figure

FRAPCON-2 Developmental Assessment

FRAPCON-2 calculations using all mechanical and gas release options are compared with well-characterized experimental data and with calculations of generic fuel rod response by FRAPCON-1. These comparisons indicate that FRAPCON-2 is capable of analyzing the fuel rod response for the wide range of cases for which the code was designed and compares well with experimental data

Diseño y fabricación de un prototipo a pequeña escala de una turbina de aire, para el aprovechamiento de la energía marina, a bajo coste mediante técnicas de prototipado rápido

Existen diferentes procedimientos para aprovechar la energía de las olas [1]. El procedimiento que cuenta con mayor rendimiento y menor coste de mantenimiento es el de Columna Oscilante de Agua (OWC). El sistema consiste en la generación del movimiento de una turbina con el aire generado por el vaivén de la olas, con el problema añadido de que el flujo de aire es bidireccional. Actualmente la única turbina que puede girar en un solo sentido independientemente del sentido del flujo de aire es la turbina Wells [2]. Existen pocos estudios teóricos publicados sobre este tipo de turbina. En este artículo se describe la metodología para desarrollar un prototipo de bajo coste (de aproximadamente 150€) de una turbina Wells, a escala, para poder contrastar los resultados obtenidos experimentalmente con los propuestos de forma teórica. Se analizarán de igual forma tanto las ecuaciones propuestas obtenidas de forma teórica como los resultados experimentales. En el diseño de la turbina se ha partido de unos parámetros fijos: álabes de perfil simétrico NACA 0018, las dimensiones del tubo y el caudal de aire previsto y se han calculado el resto de los parámetros a partir de ecuaciones de aerodinámica [3],[4]. Posteriormente se ha realizado el diseño gráfico con un CAD y se ha fabricado el prototipo mediante sinterizado láser y mecanizado de control numérico. Finalmente se ha montado un motor de corriente continua para determinar la potencia generada en vacío. Se ha construido el prototipo y se ha determinado la velocidad de giro y la potencia generada en función del caudal de aire circulante por el tubo.Peer Reviewe