Catálogo de los braquiópodos españoles del Jurásico inferior depositados en el Museo Geominero (ITGE, Madrid)

Se revisan desde el punto de vista taxonómico y bioestratigráfico los braquiópodos españoles del Jurásico Inferior que constituyen la colección del Museo Geominero. La colección está compuesta por 1102 ejemplares procedentes de 98 localidades diferentes repartidas fundamentalmente por el sector nororiental de la Península Ibérica. Se han identificado 23 géneros (10 de rinconélidos, 3 de espiriféridos y 10 de terebratúlidos) y 59 especies (24 de rinconélidos, 5 de espiriféridos y 30 de terebratúlidos)

Interface optical phonons in spheroidal dots: Raman selection rules

The contribution of interface phonons to the first order Raman scattering in nanocrystals with non spherical geometry is analyzed. Interface optical phonons in the spheroidal geometry are discussed and the corresponding Frohlich-like electron-phonon interaction is reported in the framework of the dielectric continuum approach. It is shown that the interface phonon modes are strongly dependent on the nanocrystal geometry, particularly on the ellipsoid's semi-axis ratio. The new Raman selection rules have revealed that solely interface phonon modes with even angular momentum are allowed to contribute to the first order phonon-assisted scattering of light. On this basis we are able to give an explanation for the observed low frequency shoulders present in the Raman cross-section of several II-VI semiconductor nanostructures.Comment: 8 pages, 2 figure

Inclusion In, and Exclusion From, Open Education Communities

This special issue is the fifth devoted to Open Educational Resources (OER) and the fourth to be drawn from papers presented at the annual UK-based OER conference. For this special issue, the editors selected papers from the OER14 conference, held in Newcastle in April 2014. The main conference theme was ‘Building communities of open practice’ with further themes on MOOCs and open courses; academic practice, development and pedagogy; open policy, research, scholarship and access; and students as users and co-creators. As open education matures it will be the communities we develop that make a difference to the success (or failure) of transforming education through openness. The five chosen papers in this special issue exemplify one facet of building communities of open practice – how people may, in theory and in practice, be included in or excluded from such communities despite the potential of the openness on offer

Evolución de las actitudes hacia la estadística en estudiantes de psicología

La Estadística se ha incorporado en forma generalizada al currículum de la mayoría de estudios universitarios como fruto del importante papel que desempeña en la formación científica y técnica de profesionales de muy variado perfil. Su estudio ayuda al desarrollo personal, fomentando un razonamiento crítico, basado en la valoración de la evidencia objetiva; así hemos de ser capaces de usar los datos para controlar nuestros juicios e interpretar los de los demás

Electron-phonon interaction in quantum-dot/quantum-well semiconductor heterostructures

Polar optical phonons are studied in the framework of the dielectric continuum approach for a prototypical quantum-dot/quantum-well (QD/QW) heterostructure, including the derivation of the electron-phonon interaction Hamiltonian and a discussion of the effects of this interaction on the electronic energy levels. The particular example of the CdS/HgS QD/QW is addressed and the system is modelled according to the spherical geometry, considering a core sphere of material "1" surrounded by a spherically concentric layer of material "2", while the whole structure is embedded in a host matrix assumed as an infinite dielectric medium. The strength of the electron-LO phonon coupling is discussed in details and the polaronic corrections to both ground state and excited state electron energy levels are calculated. Interesting results concerning the dependence of polaronic corrections with the QD/QW structure size are analyzed.Comment: 8 pages, 5 figure

Interband electron Raman scattering in a quantum wire in a transverse magnetic field

Electron Raman scattering (ERS) is investigated in a parabolic semiconductor quantum wire in a transverse magnetic field neglecting by phonon-assisted transitions. The ERS cross-section is calculated as a function of a frequency shift and magnetic field. The process involves an interband electronic transition and an intraband transition between quantized subbands. We analyze the differential cross-section for different scattering configurations. We study selection rules for the processes. Some singularities in the Raman spectra are found and interpreted. The scattering spectrum shows density-of-states peaks and interband matrix elements maximums and a strong resonance when scattered frequency equals to the "hybrid" frequency or confinement frequency depending on the light polarization. Numerical results are presented for a GaAs/AlGaAs quantum wire.Comment: 8 pages, 5 figure

Premartensitic transition driven by magnetoelastic interaction in bcc ferromagnetic Ni2MnGaNi_{2}MnGa

We show that the magnetoelastic coupling between the magnetization and the amplitude of a short wavelength phonon enables the existence of a first order premartensitic transition from a bcc to a micromodulated phase in $Ni_{2}MnGa$. Such a magnetoelastic coupling has been experimentally evidenced by AC susceptibility and ultrasonic measurements under applied magnetic field. A latent heat around 9 J/mol has been measured using a highly sensitive calorimeter. This value is in very good agreement with the value predicted by a proposed model.Comment: 4 pages RevTex, 3 Postscript figures, to be published in Physical Review Letter

Using WWW to improve software development and maintenance: application of the LIGHT system to ALEPH programs

Programmers who develop, use, maintain, modify software and faced with the problem of scanning and understanding large amounts of documents, ranging from source code to requirements, analysis and design diagrams, user and reference manuals etc. This task is non trivial and time consuming LIGHT, LIfe cycle Global HyperText is an attempt to solve the problem using WWW technology. The basic idea is to make all the software documents, including code, available and cross-connected on the WWW. The first application of this concept to go in production is JULIA?LIGHT, a system to convert and publish on WWW the software documentation of the JULIA reconstruction program of the ALEPH experiment at CERN European Organisation for Particle Physics, Geneva