4,726 research outputs found
Mapping the Curricular Structure and Contents of Network Science Courses
As network science has matured as an established field of research, there are
already a number of courses on this topic developed and offered at various
higher education institutions, often at postgraduate levels. In those courses,
instructors adopted different approaches with different focus areas and
curricular designs. We collected information about 30 existing network science
courses from various online sources, and analyzed the contents of their syllabi
or course schedules. The topics and their curricular sequences were extracted
from the course syllabi/schedules and represented as a directed weighted graph,
which we call the topic network. Community detection in the topic network
revealed seven topic clusters, which matched reasonably with the concept list
previously generated by students and educators through the Network Literacy
initiative. The minimum spanning tree of the topic network revealed typical
flows of curricular contents, starting with examples of networks, moving onto
random networks and small-world networks, then branching off to various
subtopics from there. These results illustrate the current state of consensus
formation (including variations and disagreements) among the network science
community on what should be taught about networks and how, which may also be
informative for K--12 education and informal education.Comment: 17 pages, 11 figures, 2 tables; to appear in Cramer, C. et al.
(eds.), Network Science in Education -- Tools and Techniques for Transforming
Teaching and Learning (Springer, 2017, in press
On in situ Determination of Earth Matter Density in Neutrino Factory
We point out that an accurate in situ determination of the earth matter
density \rho is possible in neutrino factory by placing a detector at the magic
baseline, L = \sqrt{2} \pi / G_{F} N_{e} where N_{e} denotes electron number
density. The accuracy of matter density determination is excellent in a region
of relatively large theta_{13} with fractional uncertainty \delta \rho / \rho
of about 0.43%, 1.3%, and \lsim 3% at 1 sigma CL at sin^2 2theta_{13}=0.1,
10^{-2}, and 3 x 10^{-3}, respectively. At smaller theta_{13} the uncertainty
depends upon the CP phase delta, but it remains small, 3%-7% in more than 3/4
of the entire region of delta at sin^2 2theta_{13} = 10^{-4}. The results would
allow us to solve the problem of obscured CP violation due to the uncertainty
of earth matter density in a wide range of theta_{13} and delta. It may provide
a test for the geophysical model of the earth, or it may serve as a method for
stringent test of the MSW theory of neutrino propagation in matter once an
accurate geophysical estimation of the matter density is available.Comment: 21 pages, 4 figures, version to appear in PR
ORIGAMIX, a CdTe-based spectro-imager development for nuclear applications
The Astrophysics Division of CEA Saclay has a long history in the development
of CdTe based pixelated detection planes for X and gamma-ray astronomy, with
time-resolved imaging and spectrometric capabilities. The last generation,
named Caliste HD, is an all-in-one modular instrument that fulfills
requirements for space applications. Its full-custom front-end electronics is
designed to work over a large energy range from 2 keV to 1 MeV with excellent
spectroscopic performances, in particular between 10 and 100 keV (0.56 keV FWHM
and 0.67 keV FWHM at 13.9 and 59.5 keV). In the frame of the ORIGAMIX project,
a consortium based on research laboratories and industrials has been settled in
order to develop a new generation of gamma camera. The aim is to develop a
system based on the Caliste architecture for post-accidental interventions or
homeland security, but integrating new properties (advanced spectrometry,
hybrid working mode) and suitable for industry. A first prototype was designed
and tested to acquire feedback for further developments. In this study, we
particularly focused on spectrometric performances with high energies and high
fluxes. Therefore, our device was exposed to energies up to 700 keV (133Ba,
137Cs) and we measured the evolution of energy resolution (0.96 keV at 80 keV,
2.18 keV at 356 keV, 3.33 keV at 662 keV). Detection efficiency decreases after
150 keV, as Compton effect becomes dominant. However, CALISTE is also designed
to handle multiple events, enabling Compton scattering reconstruction, which
can drastically improve detection efficiencies and dynamic range for higher
energies up to 1408 keV (22Na, 60Co, 152Eu) within a 1-mm thick detector. In
particular, such spectrometric performances obtained with 152Eu and 60Co were
never measured before with this kind of detector.Comment: Nuclear Instruments and Methods in Physics Research Section A:
Accelerators, Spectrometers, Detectors and Associated Equipment. Available
online 9 January 2015, ISSN 0168-9002
(http://www.sciencedirect.com/science/article/pii/S0168900215000133).
Keywords: CdTe; X-ray; Gamma-ray; Spectrometry; Charge-sharing; Astrophysics
Instrumentation; Nuclear Instrumentation; Gamma-ray camera
La gestion des risques et analyse comportementale d’une pratique inversée : une exemple avec le risque pays
La gestion des risques, prĂ©sentĂ©e en thĂ©orie comme parfaitement scientifique, suit souvent enÂ
pratique un cycle inverse Ă celui prĂ©conisĂ©, la rĂ©alisation du risque conditionnant les dĂ©cisionsÂ
prises. L’application de la thĂ©orie des perspectives de Kahneman et Tversky permet deÂ
comprendre pourquoi « tout change » lorsqu’une catastrophe survient. Le point de vue, via leÂ
point de rĂ©fĂ©rence, n’est plus le mĂŞme. A titre d’exemple, ceci explique, les variations rapidesÂ
des notations dans l’analyse du risque pays
Mechanical Unfolding of a Simple Model Protein Goes Beyond the Reach of One-Dimensional Descriptions
We study the mechanical unfolding of a simple model protein. The Langevin
dynamics results are analyzed using Markov-model methods which allow to
describe completely the configurational space of the system. Using transition
path theory we also provide a quantitative description of the unfolding
pathways followed by the system. Our study shows a complex dynamical scenario.
In particular, we see that the usual one-dimensional picture: free-energy vs
end-to-end distance representation, gives a misleading description of the
process. Unfolding can occur following different pathways and configurations
which seem to play a central role in one-dimensional pictures are not the
intermediate states of the unfolding dynamics.Comment: 10 pages, 6 figure
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