936 research outputs found
Two-photon finite-pulse model for resonant transitions in attosecond experiments
We present an analytical model capable of describing two-photon ionization of
atoms with attosecond pulses in the presence of intermediate and final isolated
autoionizing states. The model is based on the finite-pulse formulation of
second-order time-dependent perturbation theory. It approximates the
intermediate and final states with Fano's theory for resonant continua, and it
depends on a small set of atomic parameters that can either be obtained from
separate \emph{ab initio} calculations, or be extracted from few selected
experiments. We use the model to compute the two-photon resonant photoelectron
spectrum of helium below the N=2 threshold for the RABITT (Reconstruction of
Attosecond Beating by Interference of Two-photon Transitions) pump-probe
scheme, in which an XUV attosecond pulse train is used in association to a weak
IR probe, obtaining results in quantitative agreement with those from accurate
\emph{ab initio} simulations. In particular, we show that: i) Use of finite
pulses results in a homogeneous red shift of the RABITT beating frequency, as
well as a resonant modulation of the beating frequency in proximity of
intermediate autoionizing states; ii) The phase of resonant two-photon
amplitudes generally experiences a continuous excursion as a function of the
intermediate detuning, with either zero or overall variation.Comment: 23 pages, 13 figure
Identification and Characterization of White Grape Varieties Autochthonous of aWarm Climate Region (Andalusia, Spain)
The high sensitivity of one of the most important crops in the world, such as vine (Vitis vinifera L.), to particular changes caused by the phenomena associated with global warming, is encouraging the wine industry to place value on grape varieties that are autochthonous to each production area. These are generally conserved in germplasm banks and may pose a useful tool to counteract the effects of climate change. In order to determine the actual resource that such varieties constitute, this research has carried out a genetic identification, a morphological characterization, and an analysis of the grape musts obtained from four autochthonous varieties (Cañocazo, Castellano, Mantúo de Pilas, and Palomino Fino). This genetic analysis has allowed the identification of autochthonous varieties with different genotypes. However, all of them had similar phenotypic characteristics in terms of high hair density in adult leaves. With respect to the physicochemical composition of the musts, significant differences have been observed between the autochthonous varieties, with respect to the control variety of Palomino Fino. Nevertheless, all of them have exhibited an adequate physicochemical composition to produce quality white wines. For all of the above reasons, these local varieties should be considered suitable for cultivation in areas with warmer and drier climates, such as Andalusia (Spain)
Números cromosomáticos de plantas occidentales, 261-269
Se indican los números cromosomáticos de nueve táxones estudiados en botones florales procedentes de plantas silvestres. El material se fijó con cloroformo, etanol y ácido acético (4:3:1) efectuándose la tinción según la técnica de SNOW (1963). Los pliegos testigo se conservan en el herbario del Departamento de Botánica de la Facultad de Ciencias, Universidad de Córdoba (COFC)
The soft-photon approximation in infrared-laser-assisted atomic ionization by extreme-ultraviolet attosecond-pulse trains
We use the soft-photon approximation, formulated for finite pulses,
to investigate the effects of the dressing pulse duration and intensity on simulated
attosecond pump–probe experiments employing trains of attosecond extremeultraviolet
pulses in conjunction with an IR probe pulse.We illustrate the validity
of the approximation by comparing the modelled photoelectron distributions for
the helium atom, in the photon energy region close to the N = 2 threshold, to
the results from the direct solution of the time-dependent Schr¨odinger equation
for two active electrons. Even in the presence of autoionizing states, the
model accurately reproduces most of the background features of the ab initio
photoelectron spectrum in the 1s channel. A splitting of the photoelectron
harmonic signal along the polarization axis, in particular, is attributed to the
finite duration of the probe pulse. Furthermore, we study the dependence of the
sideband integrated signal on the pump–probe time delay for increasing IR field
strengths. Starting at IR intensities of the order of 1TWcm−2, overtones in the
sideband oscillations due to the exchange of three or more IR photons start to
appear. We derive an analytical expression in the frequency-comb limit of the soft-photon model for the amplitude of all the sideband frequency components
and show that these amplitudes oscillate as a function of the intensity of the IR
field. In particular, we predict that the amplitude of the fundamental component
with frequency 2!IR, on which the rabitt optical reconstruction technique is
based, changes sign periodicallyWe thank Mare Nostrum BSC and CCC-UAM (Centro de Computación Científica,
Universidad Autónoma de Madrid) for allocation of computer time. The research leading
to these results has received funding from the European Research Council under the
European Union’s Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement
number 290853, the European COST Actions CM0702 and CM1204, the ERA-Chemistry
project number PIM2010EEC-00751, the Marie Curie ITN CORINF and the MICINN projects
numbers FIS2010-15127 and CSD 2007-00010 (Spain
Coordinating heterogeneous IoT devices by means of the centralized vision of the SDN controller
The IoT (Internet of Things) has become a reality during recent years. The desire of having everything connected to the Internet results in clearly identified benefits that will impact on socio economic development. However, the exponential growth in the number of IoT devices and their heterogeneity open new challenges that must be carefully studied. Coordination among devices to adapt them to their users' context usually requires high volumes of data to be exchanged with the cloud. In order to reduce unnecessary communications and network overhead, this paper proposes a novel network architecture based on the Software-Defined Networking paradigm that allows IoT devices coordinate and adapt them within the scope of a particular context.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Estudio palinológico de Zygohyllaceae L. en la Península Ibérica
En es te trabajo se estudia la palinologla de los t axones de Zygoph,r llaceae representados en la Península Ib6rica, medi ante micr oscopía o pt ica y electrónica de barridoIn t hls paper thc palynology of the lbcrian Zygophyl l aceae are studied by r.1ean of optic and scanni ng electron mieros cop
Nueva Ley de protección de menores
En el presente trabajo se analiza la nueva Ley Orgánica 8/2021, de 4 de junio, de protección integral a la infancia y la adolescencia frente a la violencia, situándola en el contexto de la evolución seguida hasta llegar a ella. Además, se estudia especialmente el concepto del interés superior del menor, ya que es el presupuesto esencial que justifica las modificaciones legislativas efectuadas, y por ello adquiere una gran relevancia en esta norma. Asimismo, se estudian sus aspectos más relevantes, entre los que se incluye el concepto de protección integral, que sirve para dar una mayor protección a los menores al otorgarles protección antes de que sucedan los hechos que les puedan dañar. De igual modo, se determinan los niveles y ámbitos de actuación que se establecen en la Ley. Finalmente, se examinan todas las modificaciones que dicha ley ha realizado en otras normativas.The present work analyzed the new Ley Orgánica 8/2021, de 4 de junio, de protección integral a la infancia y la adolescencia frente a la violencia, placing it in the context of the evolution that led to it. In addition, the concept of the higher interest of the minor is studied, since it is the essential assumption that justifies the legeslative modifications made and for this reason it acquires great relevance in this regulation. Likewise, the most relevant aspects are studied, among which is included the concept of comprehensive protection, which serves to give a greater protection to minors by granting them protection before the events that may harm them occur. In the same way, the levels and scopes of action are established in the Law are determined. Finally, all the modifications that said law has made in other regulations are examined.Máster Universitario en Acceso a la Profesión de Abogado (M155
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