Spreading and shortest paths in systems with sparse long-range connections

Spreading according to simple rules (e.g. of fire or diseases), and shortest-path distances are studied on d-dimensional systems with a small density p per site of long-range connections (``Small-World'' lattices). The volume V(t) covered by the spreading quantity on an infinite system is exactly calculated in all dimensions. We find that V(t) grows initially as t^d/d for t>t^*$, generalizing a previous result in one dimension. Using the properties of V(t), the average shortest-path distance \ell(r) can be calculated as a function of Euclidean distance r. It is found that \ell(r) = r for r<r_c=(2p \Gamma_d (d-1)!)^{-1/d} log(2p \Gamma_d L^d), and \ell(r) = r_c for r>r_c. The characteristic length r_c, which governs the behavior of shortest-path lengths, diverges with system size for all p>0. Therefore the mean separation s \sim p^{-1/d} between shortcut-ends is not a relevant internal length-scale for shortest-path lengths. We notice however that the globally averaged shortest-path length, divided by L, is a function of L/s only.Comment: 4 pages, 1 eps fig. Uses psfi

Réadaptation et psychose : de l’enveloppe soignante à l’enveloppe sociale

International audienceAfter a theoretical reminder of main notions of readjustment, rehabilitation, reintegration, the authors broaden the thought on readjustment from clinical experience near chronic psychotic patients in therapeutic flats.They show how the patient converts his ties with his circle and social world, through a new psychic organization with moments of crisis: the patient must gradually free oneself from “nursing envelope” to invest others envelopes, before being able to integrate a new group which constitute “social envelope”.Après un rappel théorique des notions essentielles de réadaptation, réhabilitation et réinsertion, les auteurs ouvrent la réflexion sur la réadaptation à partir d’une expérience clinique auprès de patients psychotiques chroniques en appartements thérapeutiques. Ils montrent comment le patient réaménage ses liens à son entourage et au monde social, à travers une réorganisation psychique parsemée de moments de crise: le patient doit progressivement se détacher de l’«enveloppe soignante» pour investir des enveloppes substitutives, avant de pouvoir intégrer un nouveau groupe constitutif de l’«enveloppe sociale»

Réadaptation et psychose : de l'enveloppe soignante à l'enveloppe sociale

International audienceAfter a theoretical reminder of main notions of readjustment, rehabilitation, reintegration, the authors broaden the thought on readjustmentfrom clinical experience near chronic psychotic patients in therapeutic flats.They show how the patient converts his tieswith his circle and social world, through a new psychic organization with moments of crisis: the patient must gradually free oneselffrom “nursing envelope” to invest others envelopes, before being able to integrate a new group which constitute “social envelope”.Après un rappel théorique des notions essentielles de réadaptation,réhabilitation et réinsertion,les auteurs ouvrent la réflexion sur la réadaptation à partir d’une expérience clinique auprès de patients psychotiques chroniques en appartements thérapeutiques. Ils montrent comment le patient réaménage ses liens à son entourage et au monde social,à travers une réorganisation psychique par-semée de moments de crise:le patient doit progressivement se détacher de l’«enveloppe soignante» pour investir des enveloppes substitutives,avant de pouvoir intégrer un nouveau groupe constitutif de l’«enveloppe sociale

Targeting RyR Activity Boosts Antisense Exon 44 and 45 Skipping in Human DMD Skeletal or Cardiac Muscle Culture Models.

Systemic delivery of antisense oligonucleotides (AO) for DMD exon skipping has proven effective for reframing DMD mRNA, rescuing dystrophin expression, and slowing disease progression in animal models. In humans with Duchenne muscular dystrophy treated with AOs, low levels of dystrophin have been induced, and modest slowing of disease progression has been observed, highlighting the need for improved efficiency of human skipping drugs. Here, we demonstrate that dantrolene and Rycals S107 and ARM210 potentiate AO-mediated exon skipping of exon 44 or exon 45 in patient-derived myotube cultures with appropriate mutations. Further, dantrolene is shown to boost AO-mediated exon skipping in patient-derived, induced cardiomyocyte cultures. Our findings further validate the ryanodine receptors (RyR) as the likely target responsible for exon skip boosting and demonstrate potential applicability beyond exon 51 skipping. These data provide preclinical support of dantrolene trial as an adjuvant to AO-mediated exon-skipping therapy in humans and identify a novel Rycal, ARM210, for development as a potential exon-skipping booster. Further, they highlight the value of mutation-specific DMD culture models for basic discovery, preclinical drug screening and translation of personalized genetic medicines

Evolution of reference networks with aging

We study the growth of a reference network with aging of sites defined in the following way. Each new site of the network is connected to some old site with probability proportional (i) to the connectivity of the old site as in the Barab\'{a}si-Albert's model and (ii) to $\tau^{-\alpha}$, where $\tau$ is the age of the old site. We consider $\alpha$ of any sign although reasonable values are $0 \leq \alpha \leq \infty$. We find both from simulation and analytically that the network shows scaling behavior only in the region $\alpha < 1$. When $\alpha$ increases from $-\infty$ to 0, the exponent $\gamma$ of the distribution of connectivities ($P(k) \propto k^{-\gamma}$ for large $k$) grows from 2 to the value for the network without aging, i.e. to 3 for the Barab\'{a}si-Albert's model. The following increase of $\alpha$ to 1 makes $\gamma$ to grow to $\infty$. For $\alpha>1$ the distribution $P(k)$ is exponentional, and the network has a chain structure.Comment: 4 pages revtex (twocolumn, psfig), 5 figure

Plasticidad y evolutividad de los pacientes psicôticos en psicoterapia

International audienceThis writing maintains thé idea of change of psychic process with psychoticpatients. By proping up thé psychomerapy of a schizophrénie patient, thé authors show psychotic patient's évolution, byemphasizing thé modification of défensive mechanisms, of type of anguish, and thé transformation of status of deliriousideas. This évolution finds one of its expressions in thé relation with another ; so thé setting of therapeutic relation containsthé mark of it, as thé change of psychotic transfer and of clinician's psychic position bring out.Cet écrit soutient l'idée d'une plasticité du fonctionnement psychique des patients psychotiques. En s'étayant sur le suivid'un patient schizophrène, les auteurs montrent l'évolutivité du patient psychotique, en insistant sur la modification desmécanismes défensifs, du type d'angoisse et sur la transformation du statut des idées délirantes. Cette évolution trouve unede ses expressions dans la relation à un autre que soi ; le cadre de la relation psychothérapeutique en contient donc lamarque, comme le met en évidence le changement du transfert psychotique et du positionnement psychique du clinicien.El articule sostiene la idea de una plasticidad delfuncionamiento psfquico de los pacientes psicôticos. Basândose en el seguimiento de un paciente esquizofrénico, losautores muestran la evolutividad del paciente psicôtico, haciendo hincapié sobre la modificaciôn de los mécanismesdéfensives, del tipo de ansiedad y sobre la transformaciôn del estatuto de las ideas délirantes. Esta evoluciôn encuentra unade sus expresiones en la relaciôn a otro que a uno mismo; el marco de la relaciôn psicoterapéutica contiene la marca de ello,como lo demuestra el cambio de la transferencia psicôtica y el cambio del posicionamiento psfquico del terapeuta

Quantized conductance in a one-dimensional ballistic oxide nanodevice

Electric-field effect control of two-dimensional electron gases (2-DEG) has enabled the exploration of nanoscale electron quantum transport in semiconductors. Beyond these classical materials, transition metal-oxide-based structures have d-electronic states favoring the emergence of novel quantum orders absent in conventional semiconductors. In this context, the LaAlO3/SrTiO3 interface that combines gate-tunable superconductivity and sizeable spin-orbit coupling is emerging as a promising platform to realize topological superconductivity. However, the fabrication of nanodevices in which the electronic properties of this oxide interface can be controlled at the nanoscale by field-effect remains a scientific and technological challenge. Here, we demonstrate the quantization of conductance in a ballistic quantum point contact (QPC), formed by electrostatic confinement of the LaAlO3/SrTiO3 2-DEG with a split-gate. Through finite source-drain voltage, we perform a comprehensive spectroscopic investigation of the 3d energy levels inside the QPC, which can be regarded as a spectrometer able to probe Majorana states in an oxide 2-DEG

Low Momentum Scattering in the Dirac Equation

It is shown that the amplitude for reflection of a Dirac particle with arbitrarily low momentum incident on a potential of finite range is -1 and hence the transmission coefficient T=0 in general. If however the potential supports a half-bound state at k=0 this result does not hold. In the case of an asymmetric potential the transmission coefficient T will be non-zero whilst for a symmetric potential T=1.Comment: 12 pages; revised to include additional references; to be published in J Phys

Mean-field solution of the small-world network model

The small-world network model is a simple model of the structure of social networks, which simultaneously possesses characteristics of both regular lattices and random graphs. The model consists of a one-dimensional lattice with a low density of shortcuts added between randomly selected pairs of points. These shortcuts greatly reduce the typical path length between any two points on the lattice. We present a mean-field solution for the average path length and for the distribution of path lengths in the model. This solution is exact in the limit of large system size and either large or small number of shortcuts.Comment: 14 pages, 2 postscript figure