19,672 research outputs found
Hemispheric specialization in selective attention and short-term memory: a fine-coarse model of left- and right-ear disadvantages.
Serial short-term memory is impaired by irrelevant sound, particularly when the sound changes acoustically. This acoustic effect is larger when the sound is presented to the left compared to the right ear (a left-ear disadvantage). Serial memory appears relatively insensitive to distraction from the semantic properties of a background sound. In contrast, short-term free recall of semantic-category exemplars is impaired by the semantic properties of background speech and is relatively insensitive to the sound’s acoustic properties. This semantic effect is larger when the sound is presented to the right compared to the left ear (a right-ear disadvantage). In this paper, we outline a speculative neurocognitive fine-coarse model of these hemispheric differences in relation to short-term memory and selective attention, and explicate empirical directions in which this model can be critically evaluated
Tune Determination of Strongly Coupled Betatron Oscillations in a Fast-Ramping Synchrotron
Tune identification - i.e. attribution of the spectral peak to a particular
normal mode of oscillations - can present a significant difficulty in the
presence of strong transverse coupling when the normal mode with a lower
damping rate dominates spectra of Turn-by-Turn oscillations in both planes. The
introduced earlier phased sum algorithm helped to recover the weaker normal
mode signal from the noise, but by itself proved to be insufficient for
automatic peak identification in the case of close phase advance distribution
in both planes. To resolve this difficulty we modified the algorithm by taking
and analyzing Turn-by-Turn data for two different ramps with the beam
oscillation excited in each plane in turn. Comparison of the relative
amplitudes of Fourier components allows for automatic correct tune
identification. The proposed algorithm was implemented in the Fermilab Booster
B38 console application and successfully used in tune, coupling and
chromaticity measurements.Comment: 3 pp. 3rd International Particle Accelerator Conference (IPAC 2012)
20-25 May 2012, New Orleans, Louisian
L’Affaire Galmot: Colonialism on Trial in 1931
Between 9 March and 21 March 1931 twelve men and two women, all French citizens from Guyane, were put on trial at an extraordinary session of the cour d’assises in Nantes. All were accused of looting and murder during riots which had taken place on 6 and 7 August 1928 in Cayenne; all were acquitted. Despite being one of the largest trials of the interwar period in France, the event was largely forgotten until a major exhibition staged in Nantes in 2011. Examining the public reaction to the trial in 1931, this article has two key aims. First, it will explore attitudes towards colonialism and republicanism in the provinces and metropolitan France. Second, it will use the exhibition of 2011 as a means of addressing the memorial debate to show how such recoveries of forgotten events, however laudable and necessary, risk perpetuating an image of an idealized republicanism based upon universalism
‘La Nouvelle Activité des Trafiquants de Femmes’: France, Le Havre and the Politics of Trafficking, 1919–1939
This article examines how the ‘moral panic’ about sex trafficking during the interwar years manifested itself in Le Havre, a French port which, at the beginning of the twentieth century, had become synonymous with the illegal trade. Interrogating hitherto neglected material in departmental archives, it explores how the problem of the trafficking of women (la traite des femmes) changed after 1919, how the administrative consequences of directives by the League of Nations could influence behaviours in everyday life and how an episode of female migration from Eastern Europe interacted with French political agendas to magnify and, in some cases, generate a problem
Sub-femtosecond electron bunches created by direct laser acceleration in a laser wakefield accelerator with ionization injection
In this work, we will show through three-dimensional particle-in-cell
simulations that direct laser acceleration in laser a wakefield accelerator can
generate sub-femtosecond electron bunches. Two simulations were done with two
laser pulse durations, such that the shortest laser pulse occupies only a
fraction of the first bubble, whereas the longer pulse fills the entire first
bubble. In the latter case, as the trapped electrons moved forward and
interacted with the high intensity region of the laser pulse, micro-bunching
occurred naturally, producing 0.5 fs electron bunches. This is not observed in
the short pulse simulation.Comment: AAC 201
The Future is Now: the Formation of Single Low Mass White Dwarfs in the Solar Neighborhood
Low mass helium-core white dwarfs (M < 0.45 Msun) can be produced from
interacting binary systems, and traditionally all of them have been attributed
to this channel. However, a low mass white dwarf could also result from a
single star that experiences severe mass loss on the first ascent giant branch.
A large population of low mass He-core white dwarfs has been discovered in the
old metal-rich cluster NGC 6791. There is therefore a mechanism in clusters to
produce low mass white dwarfs without requiring binary star interactions, and
we search for evidence of a similar population in field white dwarfs. We argue
that there is a significant field population (of order half of the detected
systems) that arises from old metal rich stars which truncate their evolution
prior to the helium flash from severe mass loss. There is a consistent absence
of evidence for nearby companions in a large fraction of low mass white dwarfs.
The number of old metal-rich field dwarfs is also comparable with the
apparently single low mass white dwarf population, and our revised estimate for
the space density of low mass white dwarfs produced from binary interactions is
also compatible with theoretical expectations. This indicates that this channel
of stellar evolution, hitherto thought hypothetical only, has been in operation
in our own Galaxy for many billions of years. One strong implication of our
model is that single low mass white dwarfs should be good targets for planet
searches because they are likely to arise from metal-rich progenitors. We also
discuss other observational tests and implications, including the potential
impact on SN Ia rates and the frequency of planetary nebulae.Comment: ApJ published versio
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