721 research outputs found
New approach to the visualization of international scientific collaboration
Chinchilla-RodrĂguez, Z., Vargas-Quesada, B., Hassan-Montero, Y., GonzĂĄlez-Molina, A., Moya-AnegĂłn, F. New approach to the visualization of international scientific collaboration. Information Visualization, 9 (4): 277-287, Winter 2010. DOI: 10.1057/ivs.2009.31In this study, visual representations are created in order to analyze different aspects of scientific collaboration at the international level. The main objective is to identify the international facet of research by following the flow of knowledge as expressed by the number of scientific publications, and then establishes the main geographical axes of output, showing the interrelationships of the domain, the intensity of these relations, and how the different types of collaboration are reflected in terms of visibility. Thus, the methodology has a twofold application, allowing us to detect significant differences that help characterize patterns of behaviour of a geographical system of output, along with the generation of representations that serve as interfaces for domain analysis and information retrieval.Peer reviewe
Hamiltonian Cycles on a Random Three-coordinate Lattice
Consider a random three-coordinate lattice of spherical topology having 2v
vertices and being densely covered by a single closed, self-avoiding walk, i.e.
being equipped with a Hamiltonian cycle. We determine the number of such
objects as a function of v. Furthermore we express the partition function of
the corresponding statistical model as an elliptic integral.Comment: 10 pages, LaTeX, 3 eps-figures, one reference adde
The chromosphere: gateway to the corona, or the purgatory of solar physics?
I argue that one should attempt to understand the solar chromosphere not only
for its own sake, but also if one is interested in the physics of: the corona;
astrophysical dynamos; space weather; partially ionized plasmas; heliospheric
UV radiation; the transition region. I outline curious observations which I
personally find puzzling and deserving of attention.Comment: To appear in the proceedings of the 25th NSO Workshop "Chromospheric
Structure and Dynamics. From Old Wisdom to New Insights", Memorie della
Societa' Astronomica Italiana, Eds. Tritschler et a
The Generation of Fullerenes
We describe an efficient new algorithm for the generation of fullerenes. Our
implementation of this algorithm is more than 3.5 times faster than the
previously fastest generator for fullerenes -- fullgen -- and the first program
since fullgen to be useful for more than 100 vertices. We also note a
programming error in fullgen that caused problems for 136 or more vertices. We
tabulate the numbers of fullerenes and IPR fullerenes up to 400 vertices. We
also check up to 316 vertices a conjecture of Barnette that cubic planar graphs
with maximum face size 6 are hamiltonian and verify that the smallest
counterexample to the spiral conjecture has 380 vertices.Comment: 21 pages; added a not
Future multimodal mobility scenarios within Europe
The European transport system faces multiple pressing challenges, including the need for significant emissions reduction in the sector and the provision of a seamless, multimodal journey to travellers. In order to address these challenges, a thorough understanding and assessment of different development pathways are required. This paper elaborates on four different scenarios developed within the scope of the Modus project. Based on these as well as additional insights from experts of the air and rail sector, initial implications for emissions reduction potential, travel times, or technological options are discussed
Dual-Band Transmitter and Receiver with Bowtie-Antenna in 0.13 ÎŒm SiGe BiCMOS for Gas Spectroscopy at 222 - 270 GHz
This paper presents a transmitter (TX) and a receiver (RX) with bowtie-antenna and silicon lens for gas spectroscopy at 222-270 GHz, which are fabricated in IHPâs 0.13 ÎŒm SiGe BiCMOS technology. The TX and RX use two integrated local oscillators for 222 â 256 GHz and 250 â 270 GHz, which are switched for dual-band operation. Due to its directivity of about 27 dBi, the single integrated bowtie-antenna with silicon lens enables an EIRP of about 25 dBm for the TX, and therefore a considerably higher EIRP for the 2-band TX compared to previously reported systems. The double sideband noise temperature of the RX is 20,000 K (18.5 dB noise figure) as measured by the Y-factor method. Absorption spectroscopy of gaseous methanol is used as a measure for the performance of the gas spectroscopy system with TX- and RX-modules
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