947 research outputs found
Radioscience simulations in General Relativity and in alternative theories of gravity
In this communication, we focus on the possibility to test GR with
radioscience experiments. We present a new software that in a first step
simulates the Range/Doppler signals directly from the space time metric (thus
in GR and in alternative theories of gravity). In a second step, a
least-squares fit of the involved parameters is performed in GR. This software
allows one to get the order of magnitude and the signature of the modifications
induced by an alternative theory of gravity on radioscience signals. As
examples, we present some simulations for the Cassini mission in
Post-Einsteinian gravity and with the MOND External Field Effect.Comment: 4 pages; Proceedings of "Les Rencontres de Moriond 2011 - Gravitation
session
Heavy ion irradiation of crystalline water ice
Under cosmic irradiation, the interstellar water ice mantles evolve towards a
compact amorphous state. Crystalline ice amorphisation was previously monitored
mainly in the keV to hundreds of keV ion energies. We experimentally
investigate heavy ion irradiation amorphisation of crystalline ice, at high
energies closer to true cosmic rays, and explore the water-ice sputtering
yield. We irradiated thin crystalline ice films with MeV to GeV swift ion
beams, produced at the GANIL accelerator. The ice infrared spectral evolution
as a function of fluence is monitored with in-situ infrared spectroscopy
(induced amorphisation of the initial crystalline state into a compact
amorphous phase). The crystalline ice amorphisation cross-section is measured
in the high electronic stopping-power range for different temperatures. At
large fluence, the ice sputtering is measured on the infrared spectra, and the
fitted sputtering-yield dependence, combined with previous measurements, is
quadratic over three decades of electronic stopping power. The final state of
cosmic ray irradiation for porous amorphous and crystalline ice, as monitored
by infrared spectroscopy, is the same, but with a large difference in
cross-section, hence in time scale in an astrophysical context. The cosmic ray
water-ice sputtering rates compete with the UV photodesorption yields reported
in the literature. The prevalence of direct cosmic ray sputtering over
cosmic-ray induced photons photodesorption may be particularly true for ices
strongly bonded to the ice mantles surfaces, such as hydrogen-bonded ice
structures or more generally the so-called polar ices.Comment: 22pages, 11 figures, accepted in A&
Determination of the branching ratios and
Improved branching ratios were measured for the decay in a
neutral beam at the CERN SPS with the NA31 detector: and .
From the first number an upper limit for and transitions in neutral kaon decay is derived. Using older results for the
Ke3/K3 fraction, the 3 branching ratio is found to be , about a factor three more
precise than from previous experiments
Communication Design and Space Narratives
The experience with space is achieved through projects developed according to a design perspective. In addition to collaborating on the creation of spatial narratives by promoting the experience, the design also acts in the sense of enhancing accessibility in both the physical and cognitive domain. Wayfinding systems as well as informational technological systems are informative elements that communicate with citizens, fostering experiences of greater accessibility and the creation of social space. This paper discusses the concept of space from its social dimension, questioning on how spatial narratives, places, and paths can create individual or collective experiences within urban space through Communication Design by the use of technology
Nation States, Cities, and People: Alternative Ways to Measure Globalization
In the last decade, attempts to measure globalization have multiplied, and they have led to the devising of diverse globalisation indexes. Besides other important similarities, the main feature shared by the most notable of these indexes is the fact that they use the same unit of analysis: the nation-state. This is a paradoxical situation, if one considers that one of the most distinctive characteristics of globalization is that its dynamics extend beyond the state.
Gives this premise, the aim of the article is, on the one hand, to justify in any case the use of instruments that seek to measure globalization on the basis of states, and, on the other, to propose alternative approaches to such measurement.
The paper\u2019s underlying assumption is that different approaches to the measurement of globalization are not mutually exclusive. Rather, such a plurality of perspectives is opportune given the complexity and multidimensionality of the concept of globalization
Papery Graveyards: Sense and Silence With Archives
This article seeks to explore the problematics of engaging with archives. In exploring how nonexperts may come to a new topic and area to ask pertinent questions, this article seeks to put to work the authorâs own reflexive engagements with an archive. The archives drew the author in both material and bodily senses and invited thinking about how we might reuse data or at least reengage with materials. The article challenges notions that reflexivity is circular or upholds sameness and proposes that the movement is iterative and one which seeks critical engagement with difference
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