1,611 research outputs found
The topological structure of scaling limits of large planar maps
We discuss scaling limits of large bipartite planar maps. If p is a fixed
integer strictly greater than 1, we consider a random planar map M(n) which is
uniformly distributed over the set of all 2p-angulations with n faces. Then, at
least along a suitable subsequence, the metric space M(n) equipped with the
graph distance rescaled by the factor n to the power -1/4 converges in
distribution as n tends to infinity towards a limiting random compact metric
space, in the sense of the Gromov-Hausdorff distance. We prove that the
topology of the limiting space is uniquely determined independently of p, and
that this space can be obtained as the quotient of the Continuum Random Tree
for an equivalence relation which is defined from Brownian labels attached to
the vertices. We also verify that the Hausdorff dimension of the limit is
almost surely equal to 4.Comment: 45 pages Second version with minor modification
The impact of in-season national team soccer play on injury and player availability in a professional club
This study investigated the impact of in-season national team duty on injury rates and player availability in a professional soccer club. Time-loss injuries and exposure time during club and national team duties were recorded prospectively over 5 seasons (2009–2014). A time-loss injury was sustained by 37.7% of squad members participating in national duty, all injuries occurring in match-play. The incidence (per 1000 h exposure) for national team player match-play injuries did not differ (P = 0.608) to that for all players in club competitions: 48.0 (95% CI 20.9–75.5) vs. 41.9 (95% CI 36.5–47.4), incidence rate ratio = 1.2 (CI: 0.8–2.4). The majority (58%) of national team injuries resulted in a layoff ≤1 week. Of all working days lost to injury generally, 5.2% were lost through injury on national duty. Injury incidence in the week following national duty was comparable (P = 0.818) in players participating or not: 7.8 (95% CI 3.6–12.0) vs. 7.1 (95% CI: 4.6–9.6), incidence rate ratio = 1.1 (CI: 0.7–2.7). While approximately 40% of participating players incurred a time-loss injury on national duty, no training injuries were sustained and injuries made up a negligible part of overall club working days lost to injury. Following duty, players had a similar injury risk to peers without national obligations
Secoviridae: a proposed family of plant viruses within the order Picornavirales that combines the families Sequiviridae and Comoviridae, the unassigned genera Cheravirus and Sadwavirus, and the proposed genus Torradovirus
The order Picornavirales includes several plant viruses that are currently classified into the families Comoviridae (genera Comovirus, Fabavirus and Nepovirus) and Sequiviridae (genera Sequivirus and Waikavirus) and into the unassigned genera Cheravirus and Sadwavirus. These viruses share properties in common with other picornavirales (particle structure, positive-strand RNA genome with a polyprotein expression strategy, a common replication block including type III helicase, a 3C-like cysteine proteinase and type I RNA-dependent RNA polymerase). However, they also share unique properties that distinguish them from other picornavirales. They infect plants and use specialized proteins or protein domains to move through their host. In phylogenetic analysis based on their replication proteins, these viruses form a separate distinct lineage within the picornavirales branch. To recognize these common properties at the taxonomic level, we propose to create a new family termed “Secoviridae” to include the genera Comovirus, Fabavirus, Nepovirus, Cheravirus, Sadwavirus, Sequivirus and Waikavirus. Two newly discovered plant viruses share common properties with members of the proposed family Secoviridae but have distinct specific genomic organizations. In phylogenetic reconstructions, they form a separate sub-branch within the Secoviridae lineage. We propose to create a new genus termed Torradovirus (type species, Tomato torrado virus) and to assign this genus to the proposed family Secoviridae
NP-hardness of decoding quantum error-correction codes
Though the theory of quantum error correction is intimately related to the
classical coding theory, in particular, one can construct quantum error
correction codes (QECCs) from classical codes with the dual containing
property, this does not necessarily imply that the computational complexity of
decoding QECCs is the same as their classical counterparts. Instead, decoding
QECCs can be very much different from decoding classical codes due to the
degeneracy property. Intuitively, one expect degeneracy would simplify the
decoding since two different errors might not and need not be distinguished in
order to correct them. However, we show that general quantum decoding problem
is NP-hard regardless of the quantum codes being degenerate or non-degenerate.
This finding implies that no considerably fast decoding algorithm exists for
the general quantum decoding problems, and suggests the existence of a quantum
cryptosystem based on the hardness of decoding QECCs.Comment: 5 pages, no figure. Final version for publicatio
Computing the Characteristic Polynomial of a Finite Rank Two Drinfeld Module
Motivated by finding analogues of elliptic curve point counting techniques,
we introduce one deterministic and two new Monte Carlo randomized algorithms to
compute the characteristic polynomial of a finite rank-two Drinfeld module. We
compare their asymptotic complexity to that of previous algorithms given by
Gekeler, Narayanan and Garai-Papikian and discuss their practical behavior. In
particular, we find that all three approaches represent either an improvement
in complexity or an expansion of the parameter space over which the algorithm
may be applied. Some experimental results are also presented
A simple proof of Duquesne's theorem on contour processes of conditioned Galton-Watson trees
We give a simple new proof of a theorem of Duquesne, stating that the
properly rescaled contour function of a critical aperiodic Galton-Watson tree,
whose offspring distribution is in the domain of attraction of a stable law of
index , conditioned on having total progeny , converges in
the functional sense to the normalized excursion of the continuous-time height
function of a strictly stable spectrally positive L\'evy process of index
. To this end, we generalize an idea of Le Gall which consists in using
an absolute continuity relation between the conditional probability of having
total progeny exactly and the conditional probability of having total
progeny at least . This new method is robust and can be adapted to establish
invariance theorems for Galton-Watson trees having vertices whose degrees
are prescribed to belong to a fixed subset of the positive integers.Comment: 16 pages, 2 figures. Published versio
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A review of tariff barriers and trade costs affecting the Creating Industries across European borders
Packing and Hausdorff measures of stable trees
In this paper we discuss Hausdorff and packing measures of random continuous
trees called stable trees. Stable trees form a specific class of L\'evy trees
(introduced by Le Gall and Le Jan in 1998) that contains Aldous's continuum
random tree (1991) which corresponds to the Brownian case. We provide results
for the whole stable trees and for their level sets that are the sets of points
situated at a given distance from the root. We first show that there is no
exact packing measure for levels sets. We also prove that non-Brownian stable
trees and their level sets have no exact Hausdorff measure with regularly
varying gauge function, which continues previous results from a joint work with
J-F Le Gall (2006).Comment: 40 page
Box-ball system: soliton and tree decomposition of excursions
We review combinatorial properties of solitons of the Box-Ball system
introduced by Takahashi and Satsuma in 1990. Starting with several definitions
of the system, we describe ways to identify solitons and review a proof of the
conservation of the solitons under the dynamics. Ferrari, Nguyen, Rolla and
Wang 2018 proposed a soliton decomposition of a configuration into a family of
vectors, one for each soliton size. Based on this decompositions, the authors
have proposed a family of measures on the set of excursions which induces
invariant distributions for the Box-Ball System. In this paper, we propose a
new soliton decomposition which is equivalent to a branch decomposition of the
tree associated to the excursion, see Le Gall 2005. A ball configuration
distributed as independent Bernoulli variables of parameter is in
correspondence with a simple random walk with negative drift and
infinitely many excursions over the local minima. In this case the authors have
proven that the soliton decomposition of the walk consists on independent
double-infinite vectors of iid geometric random variables. We show that this
property is shared by the branch decomposition of the excursion trees of the
random walk and discuss a corresponding construction of a Geometric branching
process with independent but not identically distributed Geometric random
variables.Comment: 47 pages, 33 figures. This is the revised version after addressing
referee reports. This version will be published in the special volume of the
XIII Simposio de Probabilidad y Procesos Estoc\'asticos, UNAM Mexico, by
Birkhause
Crise suicidaire et maladie d’Alzheimer débutante : intérêt d’une analyse neuropsychologique détaillée
RésuméIntroduction Le risque de développer une maladie d’Alzheimer augmente avec l’âge. Le rôle de celle-ci comme un facteur de risque indépendant de suicide n’est pas bien compris et demeure complexe et mal élucidé. L’objectif de cet article est d’envisager une compréhension neuropsychologique de la crise suicidaire dans le cas d’une maladie d’Alzheimer débutante. Méthode Une évaluation cognitive globale (Mini-Mental State Examination, Batterie Rapide d’Évaluation Frontale) complétée de l’exploration de l’inhibition cognitive selon ses fonctions d’accès (tâche de lecture en présence de distracteurs), de suppression (Trail Making Test), et de freinage (Stroop, Hayling, Go/No-Go) a été réalisée chez une femme souffrant d’une maladie d’Alzheimer (MMSE à 21/30) avant et après réalisation d’une tentative de suicide dans un contexte de dépression. Résultats L’échelle d’Hamilton était cotée à 24/52, l’échelle de dépression de Cornell à 21/38. L’intentionnalité suicidaire était modérée avec un score à 15/25 à l’échelle d’intentionnalité suicidaire de Beck. Initialement préservées, le déclin des fonctions exécutives a coïncidé avec l’émergence d’une crise suicidaire dans un contexte de dépression chez une patiente souffrant de maladie d’Alzheimer. Les fonctions de l’inhibition cognitive étaient altérées dans ses trois composantes, après ajustement des facteurs de confusion. Conclusion Une évaluation détaillée des fonctions exécutives et singulièrement de l’inhibition cognitive dans la population des patients atteints d’une maladie d’Alzheimer permettrait de détecter les personnes les plus à risque de passage à l’acte et de proposer une surveillance plus étroite dans le cadre des soins généraux de leur maladie. AbstractIntroduction The role of Alzheimer\u27s disease as a risk factor for suicide is unclear. The aim of this study was to understand neuropsychological component of the suicidal crisis in Alzheimer\u27s disease. Method Using an extensive neuropsychological battery, different aspects of cognitive inhibition were particularly examined: Access to relevant information (using the Reading with distraction task), suppression of no longer relevant information (Trail Making Test, Rule Shift Cards), and restraint of cognitive resources to relevant information (Stroop test, Hayling Sentence Completion test, Go/No-Go). One female Alzheimer depressed case was assessed before and after a suicide attempt. Results Ten days after the patient\u27s suicide attempt, dementia was still moderate with a MMSE score at 21/30 but with a worsening of executive functions (FAB at 8/18) in the context of depression and suicide. The Hamilton-Depression Rating Scale was at 24 (maximal score at 52), and the Cornell Scale for Depression was at 21 (maximal score at 38). Suicidal intent was moderate with a score of 9 on the Beck Suicide Intent Scale (maximal score at 25). The patient did not present a delirium, psychotic symptoms, or anosognosia. Her episodic memory was altered as shown by her semantic performance on verbal fluency (naming 12 animals in 120 seconds) and on lexical fluency (naming 8 words beginning with the letter P). Initially preserved, executive function declined during a suicidal crisis in a context of depression in Alzheimer\u27s disease case. Neuropsychological testing confirmed a dysexecutive syndrome (FAS at 8/18), with an impairment in her conceptualization capacity (MCST) and a deficit in cognitive inhibition and its access (reading task in the presence of distractors), deletion (TMT) and restraint (Stroop, Go/No-Go, Hayling) functions. Computed tomography has shown no signs of intracranial expansive process. Conclusion Assessing predictors of suicide and means of completion in patients with dementia may help the development of interventions to reduce risk of suicide among the growing population of individuals with dementia. Because of Alzheimer\u27s-related cognitive inhibition impairment, identification and intervention addressing the complex issues of depression, executive dysfunction and dementia may help clinicians to mitigate the risk of suicide in patients with Alzheimer\u27s disease
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