1,868 research outputs found
Exciting polaritons with quantum light
We discuss the excitation of polaritons---strongly-coupled states of light
and matter---by quantum light, instead of the usual laser or thermal
excitation. As one illustration of the new horizons thus opened, we introduce
Mollow spectroscopy, a theoretical concept for a spectroscopic technique that
consists in scanning the output of resonance fluorescence onto an optical
target, from which weak nonlinearities can be read with high precision even in
strongly dissipative environments.Comment: 5 pages, 3 figure
T-fold sequential-validation technique for out-of-distribution generalization with financial time series data
The temporal structure in financial time series (FTS) data demands non-trivial considerations in the use of cross-validation (CV). Such frequently used technique is based on statistical learning theory, which is founded on the assumption that training samples are i.i.d. Although there is progress in studying fundamental phenomenons in certain learning methods such as feature selection imbalance during the learning stage, it is currently widely accepted that there will be no reason to expect good out of sample results from a learning process without such strong assumption. In FTS, there are conditions under which sub-sampling data leads to overshadow the effect of non-deterministic relationships between features and the target variable among different samples. Such effect remains unnoticed given the use of the additivity property in the decomposition of objective functions for the Learning Process. Moreover, it reduces to a particular operation the relationship among samples without information attribution. We present a technique that controls information leakage and decomposes the global probability distribution into local probability distributions, providing identification of each sample contribution to the learning process, maintaining information sparsity, therefore, relaxing the effects of the i.i.d. assumption. Parametric stability, as a result, is presented for exchange rate prediction using different predictive models.ITESO, A.C
Identification of the optical and near-infrared counterpart of GRS 1758-258
Context. Understood to be a microquasar in the Galactic center region, GRS
1758-258 has not yet been unambiguously identified to have an
optical/near-infrared counterpart, mainly because of the high absorption and
the historic lack of suitable astrometric stars, which led to the use of
secondary astrometric solutions. Although it is considered with 1E 1740.7-2942
as the prototypical microquasar in the Galactic center region, the Galactic
origin of both sources has not yet been confirmed. Aims. We attempt to improve
previous astrometry to identify a candidate counterpart to GRS 1758-258. We
present observations with the Gran Telescopio de Canarias (GTC), in which we
try to detect any powerful emission lines that would infer an extragalactic
origin of this source. Methods. We use modern star catalogues to reanalyze
archival images of the GRS 1758-258 field in the optical and near-infrared
wavelengths, and compute a new astrometric solution. We also reanalyzed
archival radio data of GRS 1758-258 to determine a new and more accurate radio
position. Results. Our improved astrometric solution for the GRS 1758-258 field
represents a significant advancement on previous works and allows us to
identify a single optical/near-infrared source, which we propose as the
counterpart of GRS 1758-258. The GTC spectrum of this source is however of low
signal-to-noise ratio and does not rule out a Galactic origin. Hence, new
spectral observations are required to confirm or discard a Galactic nature.Comment: 4 pages, 3 figures, accepted by Astronomy and Astrophysic
Energy evaluation of extruded compound foods for dogs by near-infrared spectroscopy
Near-infrared reflectance spectroscopy (NIRS) was used to predictthe chemical composition, the apparent digestibility and the content ofdigestible nutrients and energy of commercial extruded compoundfoods fordogs
Cortes compensados para la deformación principal alpina en el borde sur oriental del Sistema Central español (Zona de Tamajón, Guadalajara)
Las estructuras alpinas principales del borde sur oriental del Sistema Central Español (zona de Tamajón) resultan ser dos cabalgamientos de dirección N70oE, con dirección de transporte hacia el SE, con retrocabalgamientos y fallas de transferencia asociadas. La dirección de transporte de
los cabalgamientos es coherente con la dirección de acortamiento horizontal de la "etapa Guadarrama" (N1500E), a la cual están asociados genéticamente. El efecto de los cabalgamientos en la cobertera mesozoica es el desarrollo de diferentes tipos de pliegues asimétricos. El acortamiento, deducido de la restauración de cortes geológicos, es de 17-19
Estimación de la inteligencia y valores en adolescentes
En este estudio adolescentes españoles del primer ciclo de la ESO (N=218) hicieron estimaciones de su propia inteligencia general y múltiple así como de las de su familia. Contestaron asimismo a un cuestionario relacionado con valores de autoritarismo. Los resultados están en línea con los de otros muchos estudios confirmando el efecto de género. Obteniendo las niñas valores inferiores en cuanto a la estimación de su propia inteligencia y, tanto chicos como chicas una menor estimación hacia las mujeres. El segundo aspecto analizado ha sido si aquellos que realizan sobre sí mismos una estimación superior tienen una mayor tendencia hacia al autoritarismo y las diferencias encontradas en chicos y chicas.peerReviewe
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