Decidability of the isomorphism and the factorization between minimal substitution subshifts

68 pagesClassification is a central problem for dynamical systems, in particular for families that arise in a wide range of topics, like substitution subshifts. It is important to be able to distinguish whether two such subshifts are isomorphic, but the existing invariants are not sufficient for this purpose. We first show that given two minimal substitution subshifts, there exists a computable constant R such that any factor map between these sub-shifts (if any) is the composition of a factor map with a radius smaller than R and some power of the shift map. Then we prove that it is decid-able to check whether a given sliding block code is a factor map between two prescribed minimal substitution subshifts. As a consequence of these two results, we provide an algorithm that, given two minimal substitution subshifts, decides whether one is a factor of the other and, as a straightforward corollary, whether they are isomorphic

Transition ordre-désordre induite thermiquement dans les systèmes cellulaires fluides bidimensionnels

International audienceMany systems, including biological tissues and foams, are made of highly packed units having high deformability but low compressibility. At two dimensions, these systems offer natural tesselations of plane with fixed density, in which transitions from ordered to disordered patterns are often observed, in both directions. Using a modified Cellular Potts Model algorithm that allows rapid thermalization of extensive systems, we numerically explore the order-disorder transition of monodisperse, two-dimensional cellular systems driven by thermal agitation. We show that the transition follows most of the predictions of Kosterlitz-Thouless-Halperin-Nelson-Young (KTHNY) theory developed for melting of 2D solids, extending the validity of this theory to systems with many-body interactions. In particular, we show the existence of an intermediate hexatic phase, which preserves the orientational order of the regular hexagonal tiling, but looses its positional order. In addition to shedding light on the structural changes observed in experimental systems, our study shows that soft cellular systems offer macroscopic systems in which KTHNY melting scenario can be explored, in the continuation of Bragg's experiments on bubble rafts

Decidability of the isomorphism and the factorization between minimal substitution subshifts

Classification is a central problem for dynamical systems, in particular for families that arise in a wide range of topics, like substitution subshifts. It is important to be able to distinguish whether two such subshifts are isomorphic, but the existing invariants are not sufficient for this purpose. We first show that given two minimal substitution subshifts, there exists a computable constant $R$ such that any factor map between these subshifts (if any) is the composition of a factor map with a radius smaller than $R$ and some power of the shift map. Then we prove that it is decidable to check whether a given sliding block code is a factor map between two prescribed minimal substitution subshifts. As a consequence of these two results, we provide an algorithm that, given two minimal substitution subshifts, decides whether one is a factor of the other and, as a straightforward corollary, whether they are isomorphic.Comment: 54 page

Relation between respiratory variations in pulse oximetry plethysmographic waveform amplitude and arterial pulse pressure in ventilated patients.

IntroductionRespiratory variation in arterial pulse pressure is a reliable predictor of fluid responsiveness in mechanically ventilated patients with circulatory failure. The main limitation of this method is that it requires an invasive arterial catheter. Both arterial and pulse oximetry plethysmographic waveforms depend on stroke volume. We conducted a prospective study to evaluate the relationship between respiratory variation in arterial pulse pressure and respiratory variation in pulse oximetry plethysmographic (POP) waveform amplitude.MethodThis prospective clinical investigation was conducted in 22 mechanically ventilated patients. Respiratory variation in arterial pulse pressure and respiratory variation in POP waveform amplitude were recorded simultaneously in a beat-to-beat evaluation, and were compared using a Spearman correlation test and a Bland-Altman analysis.ResultsThere was a strong correlation (r2 = 0.83; P < 0.001) and a good agreement (bias = 0.8 +/- 3.5%) between respiratory variation in arterial pulse pressure and respiratory variation in POP waveform amplitude. A respiratory variation in POP waveform amplitude value above 15% allowed discrimination between patients with respiratory variation in arterial pulse pressure above 13% and those with variation of 13% or less (positive predictive value 100%).ConclusionRespiratory variation in arterial pulse pressure above 13% can be accurately predicted by a respiratory variation in POP waveform amplitude above 15%. This index has potential applications in patients who are not instrumented with an intra-arterial catheter

Intra-parenchymal brainstem haemorrhage secondary to iatrogenic needle injury after a parenteral injection in a cat

Case summary A 6-month-old female domestic shorthair cat was presented with acute onset non-ambulatory right hemiparesis and horizontal nystagmus following an injection attempt in the neck, during which the cat did not cooperate. Magnetic resonance imaging (MRI) revealed a well-defined intra-axial lesion on the right side of the myelencephalon. The lesion was T2-weighted hypointense and T1-weighted hypointense to isointense to grey matter, non-contrast enhancing, with perilesional oedema and signal void on T2*-weighted images. A linear hyperintense lesion in the muscles of the right dorsolateral aspect of the neck on short tau inversion recovery images was also observed. These MRI findings were consistent with iatrogenic brainstem haemorrhage and a muscle needle tract. The cat made a good recovery with just mild residual neurological deficits 6 weeks after the injury. Relevance and novel information To our knowledge, this is the first report of an iatrogenic brainstem needle injury in a cat and the first report of a central nervous system iatrogenic trauma after a parenteral injection. Care should be taken with neck parenteral injections, especially in the cranial cervical area

La Formation Professionnelle Continue et les risques liés à l'emploi : une analyse exploratoire sur données longitudinales des liens entre la FPC et les changements de PCS

Cet article traite du lien entre la récurrence du passage en formation professionnelle continue (FPC) et le type de trajectoire professionnelle à partir de l'appariement des enquêtes emplois 98, 99 et 2000 et de l'enquête FC2000. Les corrélations entre le nombre de FPC et le type de trajectoires professionnelles ont montré que les ouvriers non-qualifiés ayant suivi des formations sont plus sur des trajectoires ascendantes que ceux qui n'ont pas suivi de formation. Pour les professions intermédiaires, le passage en formation continue joue sur la stabilité plutôt que sur la progression. Le fait d'appartenir à une professions et catégories socioprofessionnelles (PCS) qui a peu recours à la FPC augmente la probabilité d'avoir une trajectoire ascendante par rapport à une PCS où le taux d'accès à la FPC est fort. Cette corrélation est plus ou moins forte en fonction du degré de rareté d'accès à la formation dans chaque PCS. Autrement dit, il existe un effet différentiel de la FPC en fonction de la PCS de départ de l'individu. La formation n'est pas utilisée de manière identique suivant les différentes catégories professionnelles. Ces résultats laissent penser que la formation aurait une fonction de promotion sociale chez les PCS de type ouvriers ou employés, alors qu'elle pourrait être du domaine du maintien dans l'emploi (donc un effet lié au cumul) pour les catégories plus élevées. En d'autres termes, dans un contexte où la formation est rare, elle pourrait encore être corrélée à la notion de promotion sociale, ce qui ne serait pas le cas dans des environnements où elle est présente de manière plus importante.Risques de l'emploi; FPC - Formation professionnelle continue; Accès à la FPC; Transition professionnelle; Risque de l'emploi et du travail; trajectoire d'emploi; Enquête longitudinale; France

Towards a statement of the S-adic conjecture through examples

The $S$-adic conjecture claims that there exists a condition $C$ such that a sequence has a sub-linear complexity if and only if it is an $S$-adic sequence satisfying Condition $C$ for some finite set $S$ of morphisms. We present an overview of the factor complexity of $S$-adic sequences and we give some examples that either illustrate some interesting properties or that are counter-examples to what could be believed to be "a good Condition $C$".Comment: 2

Experimental validation of a CFD-based air quality sensor placement strategy to localize indoor source emissions

Building Simulation 2019, Rome, Italie, 02-/09/2019 - 04/09/2019Some woodborers such as termites have harmful effects on the safety of structures. As the woodborers produce some specic Volatile Organic Compounds (VOC), they can be used as an indicator to early detect their presence. Thus, innovative solutions combining gaz sensors outputs and Computational Fluid Dynamics (CFD) are studied to localize indoor source emissions. These strategies can also be applied to localize noxious indoor pollutants like formaldehyde. In this paper, we focus on the optimal placement of air quality sensors in view of localizing a maximum of source emissions on the environment surfaces. We propose an adjoint-based numerical strategy taking into account the sensor features such as the Limit Of Detection (LOD). This strategy is applied to a real 3D room and validated by an experimental campaign

In vitro screening of probiotic lactic acid bacteria and prebiotic glucooligosaccharides to select effective synbiotics

Probiotics and prebiotics have been demonstrated to positively modulate the intestinal microflora and could promote host health. Although some studies have been performed on combinations of probiotics and prebiotics, constituting synbiotics, results on the synergistic effects tend to be discordant in the published works. The first aim of our study was to screen some lactic acid bacteria on the basis of probiotic characteristics (resistance to intestinal conditions, inhibition of pathogenic strains). Bifidobacterium was the most resistant genus whereas Lactobacillus farciminis was strongly inhibited. The inhibitory effect on pathogen growth was strain dependent but lactobacilli were the most effective, especially L. farciminis. The second aim of the work was to select glucooligosaccharides for their ability to support the growth of the probiotics tested. We demonstrated the selective fermentability of oligodextran and oligoalternan by probiotic bacteria, especially the bifidobacteria, for shorter degrees of polymerisation and absence of metabolism by pathogenic bacteria. Thus, the observed characteristics confer potential prebiotic properties on these glucooligosaccharides, to be further confirmed in vivo, and suggest some possible applications in synbiotic combinations with the selected probiotics. Furthermore, the distinctive patterns of the different genera suggest a combination of lactobacilli and bifidobacteria with complementary probiotic effects in addition to the prebiotic ones. These associations should be further evaluated for their synbiotic effects through in vitro and in vivo models