788 research outputs found
Urban Planning in the First Unfortified Spanish Colonial Town: The Orientation of the Historic Churches of San Cristóbal de La Laguna
The city of San Cristóbal de La Laguna in the Canary Island of Tenerife (Spain) is of exceptional value as the first unfortified colonial city to follow regular plan - a grid, outlined by straight streets that form squares - in the overseas European expansion. It constitutes a historical example of the so-called "Town of Peace", the archetype of a city-republic in a new land that employed its own natural boundaries to delimit and defend itself. Founded in 1496, the historical centre of the old city was declared a World Heritage Site by UNESCO in 1999 (UNESCO World Heritage Committee, n.d.). We analyse the exact spatial orientation of 21 historic Christian churches currently existing in the old part of La Laguna, which we take as a good indicator of the original layout of the urban lattice. We find a clear orientation pattern that, if correlated with the rising or setting Sun, singles out an absolute-value astronomical declination slightly below 20°, which, within the margin of error of our study, might be associated with the 25th July feast day of San Cristóbal de Licia, the saint to whom the town was originally dedicated. We also discuss at some length some recent proposals which invoke somewhat far-fetched hypotheses for the planimetry of the old city and conclude with some comments on one of its outstanding features, namely its Latin-cross structure, which is apparent in the combined layout of some of its most emblematic churches.Fil: Gangui, Alejandro. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Belmonte, Juan Antonio. Instituto de Astrofísica de Canarias; Españ
The development of a Utopian city? Comparing land-and skyscapes in Santa Cruz de Tenerife and San Cristobal de la Laguna
We discuss the peculiar planning of the city of San Cristóbal de La Laguna, in the Canary Island of Tenerife (Spain), when compared to the nearby and essentially contemporary Santa Cruz de Tenerife, which served as a maritime port of the former city. For this we review our previous study of the exact spatial orientation of twenty-one historic Christian churches currently existing in the old part of La Laguna, which we compare with the analysis of six similar buildings located in Santa Cruz, and presented here for the first time. In both cities, we take the spatial orientation of historic churches as good indicators of the original layout of the respective urban lattices. Although we find a clear orientation pattern for La Laguna, which singles out an absolute-value astronomical declination slightly below 20°, pointing to a preferred date close to the July 25th feast-day of San Cristóbal de Licia, in the case of Santa Cruz this trend is not followed. On the contrary, the pattern we find for Santa Cruz, within the uncertainties due to the low statistics, and apart from one equinoctial and one solstitial oriented churches, is consistent with an orographic orientation within the canonic limits of sunrise. This result highlights the uniqueness of the city of La Laguna, and supports the idea suggesting its deliberate planning in the early 16th century.Fil: Gangui, Alejandro. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Belmonte, Juan Antonio. Instituto de Astrofísica de Canarias; Españ
Which could be the role of Hybrid Fibre Coax in Next Generation Access networks?
Next generation access networks (NGAN) will support a renewed communication structure where opportunities lie in the provision of ubiquitous broadband connectivity, a wide variety of new applications, appealing contents and a general support to the sustainable growth of diverse sectors. From their deployment it is expected a wealth of innovations, jobs creation and a new wave of economic growth. In this paper we discuss which could be the role of Hybrid Fibre Coax (HFC) in the Next Generation Access Network (NGAN) roadmap. Thus, we propose a simplified model for making approximate cost calculations for HFC deployment based on the geographic and sociodemographic characteristics of Spain. Considering the latest evolution of HFC based on DOCSIS 3.0 from integrated (I-CMTS) towards modular (M-CMTS), the results from the model are compared with the most competitive NGAN for ultrabroadband speeds: Fibre to the Home (FTTH) based on Gigabitcapable Passive Optical Networks (GPON
La opinión de los españoles ante las nuevas biotecnologías
Las nuevas biotecnologías representan una gran esperanza para el ser humano. Sin embargo, la gente tiene una percepción respecto a ellas ambivalente, donde el bien y el mal que suponen están juntos. El presente artículo trata de esta ambivalencia en España. Para ello, he analizado cuatro estudios de opinión con diferentes metodologías: grupos de discusión, entrevistas y encuestas. El trabajo de análisis realizado permite hacer una evaluación comprehensiva del conocimiento, la información, el interés, la aceptación, la percepción, la demanda de control, el conocimiento de la normativa, la participación social reclamada, la percepción del riesgo, etc. Todos ellos aspectos muy importantes para legitimar las nuevas biotecnologías, y para que ellas tengan la aceptación del público.The new biotechnologies represent a great hope for the human being, although people have a perception respect they ambivalent, where the good and the bad that suppose are join. The present article treats this ambivalence in the Spain people. For that I have analysed four public opinion studies with different methodologies: discussion groups, interviews, and inquiries. The analysis work realized permit do a comprehensive evaluation for the knowledge, information, interest, acceptation, perception, control demand, normative knowledge, social participation claims, risk perception, etc. All these items are very important for legitimate the new biotechnologies, and for that they have the public acceptation
Recent advances to understand morphology stability of organic photovoltaics
Organic photovoltaic devices are on the verge of commercialization with power conversion efficiencies
exceeding 10 % in laboratory cells and above 8.5 % in modules. However, one of the main limitations hindering their mass
scale production is the debatable inferior stability of organic photovoltaic devices in comparison to other technologies.
Adequate donor/acceptor morphology of the active layer is required to provide carrier separation and transport to the
electrodes. Unfortunately, the beneficial morphology for device performance is usually a kinetically frozen state which has
not reached thermodynamic equilibrium. During the last 5 years, special efforts have been dedicated to isolate the effects
related to morphology changes taking place within the active layer and compare to those affecting the interfaces with the
external electrodes. The current review discusses some of the factors affecting the donor/acceptor morphology evolution as
one of the major intrinsic degradation pathways. Special attention is paid to factors in the nano- and microscale domain.
For example, phase segregation of the polymer and fullerene domains due to Ostwald ripening is a major factor in the
microscale domain and is affected by the presence of additives, glass transition temperature of the polymers or use of
crosslinkers in the active layer. Alternatively, the role of vertical segregation profile toward the external electrodes is key
for device operation, being a clear case of nanoscale morphology evolution. For example, donor and acceptor molecules
actually present at the external interfaces will determine the leakage current of the device, energy-level alignment, and
interfacial recombination processes. Different techniques have been developed over the last few years to understand its
relationship with the device efficiency. Of special interest are those techniques which enable in situ analysis being nondestructive
as they can be used to study accelerated degradation experiments and some will be discussed here.This work was partially supported by FP7
European collaborative project SUNFLOWER (FP7-ICT-2011-7-
contract No. 287594), the Spanish Ministerio de Economı´a y Competitividad
(project MAT2013-47192-C3-1-R), and Generalitat
Valenciana (project ISIC/2012/008 Institute of Nanotechnologies for
Clean Energies). A.G. would like to thank the Spanish Ministerio de
Economı´a y Competitividad for a Ramo´n y Cajal Fellowship (RYC-
2014-16809)
La Arqueoastronomía en Europa: la singularidad del caso español
La arqueoastronomía es una disciplina científica relativamente joven en España. A caballo entre las ciencias sociales y la astronomía, se sirve de las poderosas herramientas de ésta para ponerse al servicio de aquellas a la hora de entender la visión del cosmos de nuestros antepasados. En el presente ensayo analizaremos el estatus de esta disciplina y estudiaremos parte de su epistemología y fundamentos. Finalmente, seguiremos de forma breve su evolución histórica en España situándola en el marco más amplio de la arqueoastronomía europea.Archaeoastronomy is a scientific discipline with a relatively short history in Spain. Straddling social sciences and astronomy, it uses the powerful tools of the latter at the service of the former in an attempt to approach the vision of the cosmos of our ancestors. In the present essay, we will analyze the current status of the discipline and will study part of its foundations and epistemology. Finally, a brief historical sketch of its development in Spain will be presented within the wider framework of European archaeoastronomy
Indoor Positioning for Monitoring Older Adults at Home: Wi-Fi and BLE Technologies in Real Scenarios
This paper presents our experience on a real case of applying an indoor localization system formonitoringolderadultsintheirownhomes. Sincethesystemisdesignedtobeusedbyrealusers, therearemanysituationsthatcannotbecontrolledbysystemdevelopersandcanbeasourceoferrors. This paper presents some of the problems that arise when real non-expert users use localization systems and discusses some strategies to deal with such situations. Two technologies were tested to provide indoor localization: Wi-Fi and Bluetooth Low Energy. The results shown in the paper suggest that the Bluetooth Low Energy based one is preferable in the proposed task
Elucidating Operating Modes of Bulk-Heterojunction Solar Cells from Impedance Spectroscopy Analysis
We discuss the progress and challenges in the application of impedance spectroscopy analysis to determine key processes and parameters in organic bulk-heterojunction solar cells. When carrier transport or outer interface extraction do not severely influence the solar cell performance, a simple method to quantify the open-circuit voltage loss caused by the kinetics of charge carrier recombination is provided, based on the determination of chemical capacitance and recombination resistance. This easily allows distinguishing between energetic and kinetic effects on photovoltage, and establishes a benchmark for the performance comparison of a set of different cells. A brief discussion of impedance analysis in the much less studied case of collection-limited solar cells is introduced.We acknowledge the financial support from Ministerio de Educacion y Ciencia (Spain) under Project HOPE CSD2007-00007 (Consolider-Ingenio 2010), and Generalitat Valenciana (Prometeo/2009/058, and ISIC/2012/008 Institute of Nanotechnologies for Clean Energies)
- …