98 research outputs found
Pairwise Well-Formed Modes and Transformations
One of the most significant attitudinal shifts in the history of music
occurred in the Renaissance, when an emerging triadic consciousness moved
musicians towards a new scalar formation that placed major thirds on a par with
perfect fifths. In this paper we revisit the confrontation between the two
idealized scalar and modal conceptions, that of the ancient and medieval world
and that of the early modern world, associated especially with Zarlino. We do
this at an abstract level, in the language of algebraic combinatorics on words.
In scale theory the juxtaposition is between well-formed and pairwise
well-formed scales and modes, expressed in terms of Christoffel words or
standard words and their conjugates, and the special Sturmian morphisms that
generate them. Pairwise well-formed scales are encoded by words over a
three-letter alphabet, and in our generalization we introduce special positive
automorphisms of , the free group over three letters.Comment: 12 pages, 3 figures, paper presented at the MCM2017 at UNAM in Mexico
City on June 27, 2017, keywords: pairwise well-formed scales and modes,
well-formed scales and modes, well-formed words, Christoffel words, standard
words, central words, algebraic combinatorics on words, special Sturmian
morphism
Critical connectedness of thin arithmetical discrete planes
An arithmetical discrete plane is said to have critical connecting thickness
if its thickness is equal to the infimum of the set of values that preserve its
-connectedness. This infimum thickness can be computed thanks to the fully
subtractive algorithm. This multidimensional continued fraction algorithm
consists, in its linear form, in subtracting the smallest entry to the other
ones. We provide a characterization of the discrete planes with critical
thickness that have zero intercept and that are -connected. Our tools rely
on the notion of dual substitution which is a geometric version of the usual
notion of substitution acting on words. We associate with the fully subtractive
algorithm a set of substitutions whose incidence matrix is provided by the
matrices of the algorithm, and prove that their geometric counterparts generate
arithmetic discrete planes.Comment: 18 pages, v2 includes several corrections and is a long version of
the DGCI extended abstrac
The finite index basis property
We describe in this paper a connection between bifix codes, symbolic dynamical systems and free groups. This is in the spirit of the connection established previously for the symbolic systems corresponding to Sturmian words. We introduce a class of sets of factors of an infinite word with linear factor complexity containing Sturmian sets and regular interval exchange
sets, namely the class of tree sets. We prove as a main result that for a uniformly recurrent tree set S, a finite bifix code X on the alphabet A is S-maximal of S-degree d if and only if it is the basis of a subgroup of index d of the free group on
AbcÚs de la prostate de découverte fortuite : A propos de deux cas
Introduction : lâabcĂšs prostatique est une pathologie de plus en plus rare. Sa symptomatologie nâest pas spĂ©cifique. LâĂ©chographie endorectale et le scanner pelvien occupent une place de choix dans le diagnostic. Le traitement repose sur lâantibiothĂ©rapie adaptĂ©e et sur le drainage percutanĂ© par voie transpĂ©rinĂ©ale, transrectale ou endoscopique. Observation : nous rapportons deux cas dâabcĂšs de prostate, lâun des patients est ĂągĂ© de 47 ans et lâautre 61 ans. Dans les deux cas, le diagnostic a Ă©tĂ© de dĂ©couverte fortuite en per opĂ©ratoire. Le scanner abdominopelvien a posĂ© le diagnostic de kyste de prostate chez lâun et une hypertrophie bĂ©nigne de la prostate chez lâautre par une Ă©chographie rĂ©no-vĂ©sico-prostatique. Le traitement a consistĂ© en un drainage par chirurgie ouverte avec une antibiothĂ©rapie adaptĂ©e. LâĂ©volution a Ă©tĂ© favorable dans les deux cas. Conclusion : lâabcĂšs prostatique est une pathologie rare et sa symptomatologie clinique nâest pas spĂ©cifique. Dans notre cas, le diagnostic nâa pu ĂȘtre confirmĂ© quâen peropĂ©ratoire et le traitement par chirurgie ouverte avec un bon rĂ©sultat
Order in glassy systems
A directly measurable correlation length may be defined for systems having a
two-step relaxation, based on the geometric properties of density profile that
remains after averaging out the fast motion. We argue that the length diverges
if and when the slow timescale diverges, whatever the microscopic mechanism at
the origin of the slowing down. Measuring the length amounts to determining
explicitly the complexity from the observed particle configurations. One may
compute in the same way the Renyi complexities K_q, their relative behavior for
different q characterizes the mechanism underlying the transition. In
particular, the 'Random First Order' scenario predicts that in the glass phase
K_q=0 for q>x, and K_q>0 for q<x, with x the Parisi parameter. The hypothesis
of a nonequilibrium effective temperature may also be directly tested directly
from configurations.Comment: Typos corrected, clarifications adde
DĂ©pistage du VIH en salle dâaccouchement Ă la maternitĂ© du Centre de SantĂ© de RĂ©fĂ©rence de la commune V Bamako
Objectifs : Evaluer lâimpact du counseling pour le dĂ©pistage VIH en salle de travail chez les patientes nâayant pas bĂ©nĂ©ficiĂ© de cette activitĂ© lors des CPN. MĂ©thodes et matĂ©riels : LâĂ©tude sâest dĂ©roulĂ©e au CSRĂ©f de la commune v de Bamako du 1er janvier au 31dĂ©cembre 2014. LâĂ©chantillonnage Ă©tait systĂ©matique, portait sur toutes les parturientes admises en salle de travail avec une dilatation cervicale Ă 4cm ou plus et dans le post- partum immĂ©diat avec un Ăąge gestationnel â„ 28SA ou un poids fĆtal â„1000g. Le test par bandelette a Ă©tĂ© utilisĂ© aprĂšs consentement Ă©clairĂ© des patientes .La confirmation a Ă©tĂ© faite avec lâimmunocomb II VIH1 et 2 Bi spot. RĂ©sultats :LâĂ©tude a rapportĂ© que 4,34% (380) des parturientes nâont pas fait le dĂ©pistage VIH lors du suivi prĂ©natal. En salle dâaccouchement, ces 380 parturientes ont bĂ©nĂ©ficiĂ© toutes dâun conseil dĂ©pistage volontaire au VIH. Nous avons enregistrĂ© 11 cas de refus. Sur les 369 parturientes ayant fait le test, 37 Ă©taient positifs au VIH soit 10%. LâĂąge moyen Ă©tait de 27ans ±07 ; non instruite (58,9%) vivant dans un rĂ©gime polygamique (65,9) ; un suivi prĂ©natal fait (95,12%) ; 93% suivi dans les structures citĂ©es PTME. Les antirĂ©troviraux ont Ă©tĂ© administrĂ©s Ă toutes les mĂšres et aux nouveau- nĂ©s vivants. Conclusion : Au regard de la frĂ©quence Ă©levĂ©e (10%) des cas positifs dans notre Ă©tude, il est nĂ©cessaire de poursuivre les activitĂ©s de Conseil et DĂ©pistage Volontaire en salle dâaccouchement pour permettre Ă lâensemble des femmes enceintes qui accouchent dans nos structures sanitaires de bĂ©nĂ©ficier des interventions de la PTM
Generic Continuous Spectrum for Ergodic Schr"odinger Operators
We consider discrete Schr"odinger operators on the line with potentials
generated by a minimal homeomorphism on a compact metric space and a continuous
sampling function. We introduce the concepts of topological and metric
repetition property. Assuming that the underlying dynamical system satisfies
one of these repetition properties, we show using Gordon's Lemma that for a
generic continuous sampling function, the associated Schr"odinger operators
have no eigenvalues in a topological or metric sense, respectively. We present
a number of applications, particularly to shifts and skew-shifts on the torus.Comment: 14 page
A chemical survey of exoplanets with ARIEL
Thousands of exoplanets have now been discovered with a huge range of masses, sizes and orbits: from rocky Earth-like planets to large gas giants grazing the surface of their host star. However, the essential nature of these exoplanets remains largely mysterious: there is no known, discernible pattern linking the presence, size, or orbital parameters of a planet to the nature of its parent star. We have little idea whether the chemistry of a planet is linked to its formation environment, or whether the type of host star drives the physics and chemistry of the planetâs birth, and evolution. ARIEL was conceived to observe a large number (~1000) of transiting planets for statistical understanding, including gas giants, Neptunes, super-Earths and Earth-size planets around a range of host star types using transit spectroscopy in the 1.25â7.8 ÎŒm spectral range and multiple narrow-band photometry in the optical. ARIEL will focus on warm and hot planets to take advantage of their well-mixed atmospheres which should show minimal condensation and sequestration of high-Z materials compared to their colder Solar System siblings. Said warm and hot atmospheres are expected to be more representative of the planetary bulk composition. Observations of these warm/hot exoplanets, and in particular of their elemental composition (especially C, O, N, S, Si), will allow the understanding of the early stages of planetary and atmospheric formation during the nebular phase and the following few million years. ARIEL will thus provide a representative picture of the chemical nature of the exoplanets and relate this directly to the type and chemical environment of the host star. ARIEL is designed as a dedicated survey mission for combined-light spectroscopy, capable of observing a large and well-defined planet sample within its 4-year mission lifetime. Transit, eclipse and phase-curve spectroscopy methods, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allow us to measure atmospheric signals from the planet at levels of 10â100 part per million (ppm) relative to the star and, given the bright nature of targets, also allows more sophisticated techniques, such as eclipse mapping, to give a deeper insight into the nature of the atmosphere. These types of observations require a stable payload and satellite platform with broad, instantaneous wavelength coverage to detect many molecular species, probe the thermal structure, identify clouds and monitor the stellar activity. The wavelength range proposed covers all the expected major atmospheric gases from e.g. H2O, CO2, CH4 NH3, HCN, H2S through to the more exotic metallic compounds, such as TiO, VO, and condensed species. Simulations of ARIEL performance in conducting exoplanet surveys have been performed â using conservative estimates of mission performance and a full model of all significant noise sources in the measurement â using a list of potential ARIEL targets that incorporates the latest available exoplanet statistics. The conclusion at the end of the Phase A study, is that ARIEL â in line with the stated mission objectives â will be able to observe about 1000 exoplanets depending on the details of the adopted survey strategy, thus confirming the feasibility of the main science objectives.Peer reviewedFinal Published versio
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