302 research outputs found
A report on the workshop on complexity in linguistics: Developmental and evolutionary perspectives
published_or_final_versio
A computational simulation of the genesis and spread of lexical items in situations of abrupt language contact
The current study presents an agent-based model which simulates the innovation and competition among lexical items in cases of language contact. It is inspired by relatively recent historical cases in which the linguistic ecology and sociohistorical context are highly complex. Pidgin and creole genesis offers an opportunity to obtain linguistic facts, social dynamics, and historical demography in a highly segregated society. This provides a solid ground for researching the interaction of populations with different pre-existing language systems, and how different factors contribute to the genesis of the lexicon of a newly generated mixed language. We take into consideration the population dynamics and structures, as well as a distribution of word frequencies related to language use, in order to study how social factors may affect the developmental trajectory of languages. Focusing on the case of Sranan in Suriname, our study shows that it is possible to account for the composition of its core lexicon in relation to different social groups, contact patterns, and large population movements
Review of the 9th international conference on the evolution of language (Evolang9)
published_or_final_versio
Probing neutron-hidden neutron transitions with the MURMUR experiment
MURMUR is a new passing-through-walls neutron experiment designed to
constrain neutron/hidden neutron transitions allowed in the context of
braneworld scenarios or mirror matter models. A nuclear reactor can act as a
hidden neutron source, such that neutrons travel through a hidden world or
sector. Hidden neutrons can propagate out of the nuclear core and far beyond
the biological shielding. However, hidden neutrons can weakly interact with
usual matter, making possible for their detection in the context of low-noise
measurements. In the present work, the novelty rests on a better background
discrimination and the use of a mass of a material - here lead - able to
enhance regeneration of hidden neutrons into visible ones to improve detection.
The input of this new setup is studied using both modelizations and
experiments, thanks to tests currently performed with the experiment at the BR2
research nuclear reactor (SCKCEN, Mol, Belgium). A new limit on the
neutron swapping probability p has been derived thanks to the measurements
taken during the BR2 Cycle 02/2019A: at 95% CL.
This constraint is better than the bound from the previous passing-through-wall
neutron experiment made at ILL in 2015, despite BR2 is less efficient to
generate hidden neutrons by a factor 7.4, thus raising the interest of such
experiment using regenerating materials.Comment: 15 pages, 8 figures, final version, accepted for publication in
European Physical Journal
Image guidance in neurosurgical procedures, the "Visages" point of view.
This paper gives an overview of the evolution of clinical
neuroinformatics in the domain of neurosurgery. It shows how
image guided neurosurgery (IGNS) is evolving according to the integration of new imaging modalities before, during and after the surgical procedure and how this acts as the premise of the Operative Room of the future. These different issues, as addressed by the VisAGeS INRIA/INSERM U746 research team (http://www.irisa.fr/visages), are presented and discussed in order to exhibit the benefits of an integrated work between physicians (radiologists, neurologists and neurosurgeons) and computer scientists to give adequate answers toward a more effective use of
images in IGNS
Postnatal Growth after Intrauterine Growth Restriction Alters Central Leptin Signal and Energy Homeostasis
Intrauterine growth restriction (IUGR) is closely linked with metabolic diseases, appetite disorders and obesity at adulthood. Leptin, a major adipokine secreted by adipose tissue, circulates in direct proportion to body fat stores, enters the brain and regulates food intake and energy expenditure. Deficient leptin neuronal signalling favours weight gain by affecting central homeostatic circuitry. The aim of this study was to determine if leptin resistance was programmed by perinatal nutritional environment and to decipher potential cellular mechanisms underneath
Rounding and Chaining LLL: Finding Faster Small Roots of Univariate Polynomial Congruences
International audienceIn a seminal work at EUROCRYPT '96, Coppersmith showed how to find all small roots of a univariate polynomial congruence in polynomial time: this has found many applications in public-key cryptanalysis and in a few security proofs. However, the running time of the algorithm is a high-degree polynomial, which limits experiments: the bottleneck is an LLL reduction of a high-dimensional matrix with extra-large coefficients. We present in this paper the first significant speedups over Coppersmith's algorithm. The first speedup is based on a special property of the matrices used by Coppersmith's algorithm, which allows us to provably speed up the LLL reduction by rounding, and which can also be used to improve the complexity analysis of Coppersmith's original algorithm. The exact speedup depends on the LLL algorithm used: for instance, the speedup is asymptotically quadratic in the bit-size of the small-root bound if one uses the Nguyen-Stehlé L2 algorithm. The second speedup is heuristic and applies whenever one wants to enlarge the root size of Coppersmith's algorithm by exhaustive search. Instead of performing several LLL reductions independently, we exploit hidden relationships between these matrices so that the LLL reductions can be somewhat chained to decrease the global running time. When both speedups are combined, the new algorithm is in practice hundreds of times faster for typical parameters
The X-ray spectrum of NGC 7213 and the Seyfert--LINER connection
We present an XMM-Newton observation of the Seyfert-LINER galaxy NGC 7213.
The RGS soft X-ray spectrum is well fitted with a power law plus soft X-ray
collisionally ionised thermal plasma (kT = 0.18 +0.03/-0.01 keV). We confirm
the presence of Fe I, XXV and XXVI K-alpha emission in the EPIC spectrum and
set tighter constraints on their equivalent widths of 82 +10/-13, 24 +9/-11 and
24 +10/-13 eV respectively. We compare the observed properties together with
the inferred mass accretion rate of NGC 7213, to those of other Seyfert and
LINER galaxies. We find that NGC 7213 has intermediate X-ray spectral
properties lying between those of the weak AGN found in the LINER M81 and
higher luminosity Seyfert galaxies. There appears to be a continuous sequence
of X-ray properties from the Galactic Centre through LINER galaxies to
Seyferts, likely determined by the amount of material available for accretion
in the central regions.Comment: 8 pages, 3 figures. Accepted for MNRA
Are quasars accreting at super-Eddington rates?
In a previous paper, Collin & Hur\'e (2001), using a sample of Active
Galactic Nuclei (AGN) where the mass has been determined by reverberation
studies (Kaspi et al. 2000), have shown that if the optical luminosity is
emitted by a steady accretion disc, about half of the objects are accreting
close to or higher than the Eddington rate. We conclude here that this result
is unavoidable, unless the masses are strongly underestimated by reverberation
studies, which does not seem to be the case. There are three issues to the
problem: 1. Accretion proceeds at Eddington or super-Eddington rates through
thick discs. Several consequences follow: an anti-correlation between the line
widths of the lines and the Eddington ratios, and a decrease of the Eddington
ratio with an increasing black hole mass. Extrapolated to all quasars, these
results imply that the amount of mass locked in massive black holes should be
larger than presently thought. 2. The optical luminosity is not produced
directly by the gravitational release of energy, and super-Eddington rates are
not required. The optical luminosity has to be emitted by a dense and thick
medium located at large distances from the center (10 to
gravitational radii). It can be due to reprocessing of the X-ray photons from
the central source in a geometrically thin warped disc, or in dense "blobs"
forming a geometrically thick system, which can be a part of the accretion flow
or the basis of an outflow. 3. Accretion discs are completely "non standard".
Presently neither the predictions of models nor the observed spectral
distributions are sufficient to help choosing between these solutions.Comment: 16 pages, 11 figures, accepted in A&
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