7,177 research outputs found
La cuestión religiosa en la Segunda República española. Iglesia y carlismo. [Reseña]
Reseña de: Antonio Manuel Moral Roncal, La cuestión religiosa
en la Segunda República española. Iglesia y carlismo,
Biblioteca Nueva, Madrid, 2009, 263 pp
Remote, informal, and ephemeral communities for testing technologies
Nowadays our world is more connected than ever, and as a consequence, truly isolated places on planet Earth are very rare. This is perhaps because humankind has always travelled beyond frontiers to explore faraway places, and also because technology enables the application of science and skills, and the extraction or collection of resources from new regions. Some technologies can change the current view and future expectations of our societies, and the way that people interact within their immediate environment. Remote communities offer the opportunity to research the next step in the evolution of technologies. Through the study of narratives, this paper investigates the remote, informal, and ephemeral communities of practices (RIE-CoP) that undertake the brief use of some technologies. The use of additive manufacturing technologies for improvised repairs, rapid tooling, the study of potential efficiency energetic measures, and previous tests in the Spanish Antarctic Base provide short-term benefits such as reducing emissions and logistics costs, and making life more sustainable on the frozen continent. Furthermore, these technology tests offer action-based research about the management and future of RIE-CoP under extreme conditions across four Antarctic missions (from December 2015 to March 2019). The experiences provide narrative foresight for the future RIE-CoP, and the results are valuable in sectors such as military and humanitarian assistance, construction, and space missions
Convective motions and net circular polarization in sunspot penumbrae
We have employed a penumbral model, that includes the Evershed flow and
convective motions inside penumbral filaments, to reproduce the azimuthal
variation of the net circular polarization (NCP) in sunspot penumbrae at
different heliocentric angles for two different spectral lines. The theoretical
net circular polarization fits the observations as satisfactorily as penumbral
models based on flux-tubes. The reason for this is that the effect of
convective motions on the NCP is very small compared to the effect of the
Evershed flow. In addition, the NCP generated by convective upflows cancels out
the NCP generated by the downflows. We have also found that, in order to fit
the observed NCP, the strength of the magnetic field inside penumbral filaments
must be very close to 1000 G. In particular, field-free or weak-field filaments
fail to reproduce both the correct sign of the net circular polarization, as
well as its dependence on the azimuthal and heliocentric angles.Comment: Accepted for publication in the Astrophysical Journal. 10 pages, 7
figures (3 in color). Uses emulatedap
Integral field spectroscopy of type-II QSOs at z=0.3-0.4
We present and analyse integral-field observations of six type-II QSOs with
z=0.3-0.4, selected from the Sloan Digital Sky Survey (SDSS). Two of our sample
are found to be surrounded by a nebula of warm ionized gas, with the largest
nebula extending across 8" (40 kpc). Some regions of the extended nebulae show
kinematics that are consistent with gravitational motion, while other regions
show relatively perturbed kinematics: velocity shifts and line widths too large
to be readily explained by gravitational motion. We propose that a ~20 kpc x20
kpc outflow is present in one of the galaxies. Possible mechanisms for
triggering the outflow are discussed. In this object, we also find evidence for
ionization both by shocks and the radiation field of the AGN.Comment: 6 pages, 5 figures, accepted by MNRAS Letter
Reconstructing the impact of human activities in a NW Iberian Roman mining landscape for the last 2500 years
This article was made available through the Brunel Open Access Publishing Fund.Little is known about the impact of human activities during Roman times on NW Iberian mining landscapes beyond the geomorphological transformations brought about by the use of hydraulic power for gold extraction. We present the high-resolution pollen record of La Molina mire, located in an area intensely used for gold mining (Asturias, NW Spain), combined with other proxy data from the same peat core to identify different human activities, evaluate the strategies followed for the management of the resources and describe the landscape response to human disturbances. We reconstructed the timing and synchronicity of landscape changes of varying intensity and form occurred before, during and after Roman times. An open landscape was prevalent during the local Late Iron Age, a period of relatively environmental stability. During the Early Roman Empire more significant vegetation shifts took place, reflected by changes in both forest (Corylus and Quercus) and heathland cover, as mining/metallurgy peaked and grazing and cultivation increased. In the Late Roman Empire, the influence of mining/metallurgy on landscape change started to disappear. This decoupling was further consolidated in the Germanic period (i.e., Visigothic and Sueve domination of the region), with a sharp decrease in mining/metallurgy but continued grazing. Although human impact was intense in some periods, mostly during the Early Roman Empire, forest regeneration occurred afterwards: clearances were local and short-lived. However, the Roman mining landscape turned into an agrarian one at the onset of the Middle Ages, characterized by a profound deforestation at a regional level due to a myriad of human activities that resulted in an irreversible openness of the landscape. © 2014 The Authors
Potential of Supercritical Carbon Dioxide Power Cycles to Reduce the Levelised Cost of Electricity of Contemporary Concentrated Solar Power Plants
This paper provides an assessment of the expected Levelised Cost of Electricity enabled by
Concentrated Solar Power plants based on Supercritical Carbon Dioxide (sCO2) technology. A global
approach is presented, relying on previous results by the authors in order to ascertain whether these
innovative power cycles have the potential to achieve the very low costs of electricity reported in the
literature. From a previous thermodynamic analysis of sCO2 cycles, three layouts are shortlisted and
their installation costs are compared prior to assessing the corresponding cost of electricity. Amongst
them, the Transcritical layout is then discarded due to the virtually impossible implementation in
locations with high ambient temperature. The remaining layouts, Allam and Partial Cooling are then
modelled and their Levelised Cost of Electricity is calculated for a number of cases and two different
locations in North America. Each case is characterised by a different dispatch control scheme and
set of financial assumptions. A Concentrated Solar Power plant based on steam turbine technology
is also added to the assessment for the sake of comparison. The analysis yields electricity costs
varying in the range from 8 to over 11 g/kWh, which is near but definitely not below the 6 g/kWh
target set forth by different administrations. Nevertheless, in spite of the results, a review of the
conservative assumptions adopted in the analysis suggests that attaining costs substantially lower
than this is very likely. In other words, the results presented in this paper can be taken as an upper
limit of the economic performance attainable by Supercritical Carbon Dioxide in Concentrated Solar
Power applications.Unión Europea (Programa Horizonte 2020) 81498
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