7,485 research outputs found
Magnetic flux in the inter-network quiet Sun from comparison with numerical simulations
Khomenko et al. estimate the mean magnetic field strength of the quiet Sun to
be 20 G. The figure is smaller than several existing estimates, and it comes
from the comparison between observed Zeeman polarization signals and synthetic
signals from numerical simulations of magneto-convection. The numerical
simulations require an artificially large magnetic diffusivity, which smears
out magnetic structures smaller than the grid scale. Assuming a turbulent
cascade for the unresolved artificially smeared magnetic fields, we find that
their unsigned magnetic flux is at least as important as that explicitly shown
in the simulation. The unresolved fields do not produce Zeeman polarization but
contribute to the unsigned flux.Since they are not considered by Khomenko et
al., their mean magnetic field strength has to be regarded as a lower limit.
This kind of bias is not specific of a particular numerical simulation or a
spectral line. It is to be expected when observed quiet Sun Zeeman signals are
compared with synthetic signals from simulations.Comment: Accepted A&A. 4 pages, 0 figure
Large Amplitude Harmonic Driving of Highly Coherent Flux Qubits
The device for the Josephson flux qubit (DJFQ) can be considered as a solid
state artificial atom with multiple energy levels. When a large amplitude
harmonic excitation is applied to the system, transitions at the energy levels
avoided crossings produce visible changes in the qubit population over many
driven periods that are accompanied by a rich pattern of interference
phenomena. We present a Floquet treatment of the periodically time-dependent
Schr\"odinger equation of the strongly driven qubit beyond the standard two
levels approach. For low amplitudes, the average probability of a given sign of
the persistent current qubit exhibits, as a function of the static flux
detuning and the driving amplitude, Landau-Zener-St\"uckelberg interference
patterns that evolve into complex diamond-like patterns for large amplitudes.
In the case of highly coherent flux qubits we find that the higher order
diamonds can not be simply described relying on a two-level approximations. In
addition we propose a new spectroscopic method based on starting the system in
the first excited state instead of in the ground state, which can give further
information on the energy level spectrum and dynamics in the case of highly
coherent flux qubits. We compare our numerical results with recent experiments
that perform amplitude spectroscopy to probe the energy spectrum of the
artificial atom.Comment: 12 Pages and 12 Figures Phys. Rev. B (in press
Micciché, Calogero: Mesogheia. Archeologia e Storia della Sicilia centro-meridionale dal VII al IV sec. a.C. (reseña)
Estudio de las urgencias en un medio rural. Adecuación de las consultas
Se pretende averiguar la demanda asistencial fuera de las horas de consulta habitual en Andratx, el grado de adecuación de las consultas y hacer varias recomendaciones para el buen funcionamiento de los P.A.C. en el medio rural. El estudio comprende 376 pacientes atendidos en uno de los tres turnos del servicio de urgencias durante seis meses. Poco más de la mitad son mujeres. Los menores de 5 años son quienes consultan más. Las urgencias representan el 59,04 % de las cuales el 34,68 % son traumatismos, heridas y efectos adversos. Las enfermedades respiratorias son la primera causa de la patología no urgente así como del total de la asistencia solicitada. El 9,04 % de pacientes precisaron envío a hospital. La mitad por traumatismos, heridas y efectos adversos. Se insiste en el inadecuado uso del servicio de urgencias. En la necesidad de estudiar el grado de adecuación de las consultas. Se propone la sustitución del término «P.A.C.» por «Servicio General de Urgencias », punto de partida para una deseable educación para la salud de la población
A multiwavelength consensus on the main sequence of star-forming galaxies at z similar to 2
We compare various star formation rate (SFR) indicators for star-forming galaxies at 1.4 < z < 2.5 in the COSMOS field. The main focus is on the SFRs from the far-IR (PACS-Herschel data) with those from the ultraviolet, for galaxies selected according to the BzK criterion. FIR-selected samples lead to a vastly different slope of the SFR-stellar mass (M-*) relation, compared to that of the dominant main-sequence population as measured from the UV, since the FIR selection picks predominantly only a minority of outliers. However, there is overall agreement between the main sequences derived with the two SFR indicators, when stacking on the PACS maps the BzK-selected galaxies. The resulting logarithmic slope of the SFR-M-* relation is similar to 0.8-0.9, in agreement with that derived from the dust-corrected UV luminosity. Exploiting deeper 24 mu m Spitzer data, we have characterized a subsample of galaxies with reddening and SFRs poorly constrained, as they are very faint in the B band. The combination of Herschel with Spitzer data has allowed us to largely break the age/reddening degeneracy for these intriguing sources, by distinguishing whether a galaxy is very red in B-z because of being heavily dust reddened, or whether because star formation has been (or is being) quenched. Finally, we have compared our SFR(UV) to the SFRs derived by stacking the radio data and to those derived from the H alpha luminosity of a sample of star-forming galaxies at 1.4 < z < 1.7. The two sets of SFRs are broadly consistent as they are with the SFRs derived from the UV and by stacking the corresponding PACS data in various mass bins
Changes and Continuity in Syracusian Democracy during the Middle of the 4th Century BC
Tradicionalmente se ha entendido la expulsión de Dionisio II de Siracusa como el inicio de un proceso de cambio orientado hacia la implantación de un sistema democrático en dicha polis que posteriormente se exportó al resto de poleis de tradición helena de Sicilia. El estudio de este sistema de gobierno, en comparación con los que le precedieron, nos permite el cuestionamiento de la visión democrática defendida tradicionalmente por los especialistas de este proceso y nos muestra una serie de pautas más similares a los gobiernos de los Dinoménidas y los Dionisios que a los ordenamientos republicanos precedentes.The expulsion of Dionysius II of Syracuse has traditionally been understood as the starting point that marked the beginning of a political change that brought the implantation of a democratic system in this polis, change that subsequently expanded to the rest of the poleis of Hellenic tradition in Sicily. The study of this political system, in comparison with those that preceded it, has allowed us to question the traditional vision withheld by specialists in the study of this democratic process, revealing a series of patterns that are more similar to the administrations lead by Dinomenids and Dionysians than to the previous republican legal systems
Reestructuración de la enseñanza superior. Postmodernidad ideológica, profesionalización liberal y mercado desregulado de la educación
La clave del modelo implícito en la actual reestructuración educativa reside en la correlación existente entre una epistemología postmoderna que cuestiona todo anclaje epistemológico, la nueva gestión de la cultura organizativa, la reconceptualización del trabajo docente en términos de una nueva profesionalización y por último, el discurso de la calidad y la excelencia que proporciona cobertura ideológica a todo ello. La financiación de la demanda que ha transformado a las universidades en PYME, obligadas a reducir sus costes para alcanzar la autosuficiencia financiera e incluso obtener ganancias, cierra en términos neoliberales la ubicación de las enseñanzas superiores en un modelo económico del saber que se sitúa fuera del control de las instituciones educativas.The key of the implied model of the present educational restructuring is based on the correlation between a postmodern epistemology which questions all of the epistemological roots, the new management of the organizational culture, the reconceptualization of the educational work by means of a new professionalization and at least, by the discourse of the quality and excellence which proportionate an ideological covering for all this process. The funding of the demand which has transformed the Universities in PYME's, which are forced to reduce its costs in order to achieve the self-funding and even to obtain benefits, it closes in neoliberal terms the location of higher universities in an economical model of knowledge which is situated outside of the educational institutions
Intelectual, político y académico. La élite de Podemos
Depto. de Sociología: Metodología y TeoríaFac. de Ciencias Políticas y SociologíaTRUEpu
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