The identification of multiple thrombophilic risk factors in an infant with cerebrovascular accident

We found 1 article: Rev Neurol. 2005 Apr 16-30;40(8):479-81. [The identification of multiple thrombophilic risk factors in an infant with cerebrovascular accident] [Article in Spanish] Neves J, Costa E, Branca R, Carrilho I, Barbot J, Barbot C. Servicio de Hematología, Hospital de Crianças Maria Pia, 4050-111 Porto, Portugal. Abstract INTRODUCTION: Neonatal stroke (NNS) incidence appears to be increasing over the last years. This is believed to be a consequence of diagnostic accuracy rather than a real amplification of this entity. Nowadays, NNS incidence is estimated to be 1:4000 full newborns. CASE REPORT: Child with left middle cerebral artery territory infarction in which several thromboembolic risk factors were documented both in the child (neonatal sepsis and factor V Leiden) and his mother (lupus anticoagulant, pre-eclampsy and factor V Leiden). CONCLUSIONS: This case supports the increasing evidence in recent reports that association of multiple prothrombotic risk factors (maternal and foetal) is present in NNS genesis. This way the authors agree that wide prothrombotic study may be of crucial interest in identifying subjacent thrombophilic disease, even when an exogenous risk factor is present. PMID: 15861329 [PubMed - indexed for MEDLINE

Event-Triggered Observers and Observer-Based Controllers for a Class of Nonlinear Systems

In this paper, we investigate the stabilization of a nonlinear plant subject to network constraints, under the assumption of partial knowledge of the plant state. The event triggered paradigm is used for the observation and the control of the system. Necessary conditions, making use of the ISS property, are given to guarantee the existence of a triggering mechanism, leading to asymptotic convergence of the observer and system states. The proposed triggering mechanism is illustrated in the stabilization of a robot with a flexible link robot.Comment: Proceedings of the 2015 American Control Conference - ACC 201

Utilização de sensores e dos sentidos humanos no apoioà transição do concretopara o abstrato

Apresentam-se e analisam-se os contributos de 4 estudos de caso para a compreensão do potencial da utilização sinérgica dos sentidos e de sensores no apoio à transição do pensamento concreto para o abstrato, em contextos de ensino experimental das ciências no 1º e 2º ciclo do ensino básico. Recolheram-se e analisaram-se evidências de desenvolvimento da abstração sobre tópicos de considerável complexidade, como os de biodiversidade, ser vivo, temperatura e frequência cardíaca

Second order sliding mode and adaptive observer for synchronization of a chaotic system: a comparative study

International audienceIn this paper two nonlinear observers for a chaotic system are compared. Moreover, the left invertible problem and the observability singularity are discussed. Thus, after a presentation of both observers, a comparison of the two proposed methods and a discussion are done on the basis of simulations results. The last part highlights the fact that the finite time observer is more sensible to the singularity observations, but less sensible to parameter uncertainties and noise in the output of the system

A robust sensorless output feedback controller of the induction motor drives: New design and experimental validation

International audienceIn this paper, a sensorless output feedback controller is designed in order to drive the Induction Motor IM without the use of flux and speed sensors. Firstly, an observer that uses only the measured stator currents is synthesized to estimate the mechanical variables (speed and load torque) and the magnetic variables (fluxes) by structurally taking into account the unobservability phenomena of the Sensorless IM (SIM) and the parametric uncertainties. Secondly, a current-based field oriented sliding mode control, that uses the flux and the speed estimates given by the former observer is developed so as to steer the estimated speed and flux magnitude to the desired references. Since the observer design is independent of the control and depends on theIM parametric uncertainties, a separation principle is introduced to guarantee the practical stability of the whole closed-loop system "observer -controller" ("O-C") according to observability and unobservability time variation. A significant benchmark taking into account the unobservability phenomena of the \textit{SIM} is presented to show the performances of the whole control scheme against experimental set-up

Collisions of particles in locally AdS spacetimes I. Local description and global examples

We investigate 3-dimensional globally hyperbolic AdS manifolds containing "particles", i.e., cone singularities along a graph $\Gamma$. We impose physically relevant conditions on the cone singularities, e.g. positivity of mass (angle less than $2\pi$ on time-like singular segments). We construct examples of such manifolds, describe the cone singularities that can arise and the way they can interact (the local geometry near the vertices of $\Gamma$). We then adapt to this setting some notions like global hyperbolicity which are natural for Lorentz manifolds, and construct some examples of globally hyperbolic AdS manifolds with interacting particles.Comment: This is a rewritten version of the first part of arxiv:0905.1823. That preprint was too long and contained two types of results, so we sliced it in two. This is the first part. Some sections have been completely rewritten so as to be more readable, at the cost of slightly less general statements. Others parts have been notably improved to increase readabilit

Atypical haemolytic-uraemic syndrome caused by factor H mutation: case report and new management strategies in children

Atypical haemolytic uraemic syndrome is causedby alternative complement pathway dysregulation. It has recently been recognised that most cases are due to genetic factors and a growing list of mutations has been described. Atypical haemolytic uraemic syndrome is associated with a dismal prognosis, a relapsing course, high acute mortality and frequent progression to end-stage renal disease. We describe a five-year-old boy admitted with a first recurrence of atypical haemolytic uraemic syndrome. The primary onset of the disease was at 15 months of age, following which there was complete recovery of haematological and renal parameters. His family history was significant in that his mother had died at the age of only 23 years of a stroke with associated thrombotic microangiopathy, suggesting a familial form of the disease. Sequencing of the gene encoding complement factor H revealed a heterozygous SCR20 mutation (3644G>T, Arg1215Leu), confirming the diagnosis. The patient was successfully treated with fresh frozen plasma infusions that induced disease remission. We also review currently evolving concepts about atypical haemolytic uraemic syndrome caused by factor H mutation, its diagnosis, the role of genetic testing and management strategies in children

Collisions of particles in locally AdS spacetimes II Moduli of globally hyperbolic spaces

We investigate 3-dimensional globally hyperbolic AdS manifolds containing "particles", i.e., cone singularities of angles less than $2\pi$ along a time-like graph $\Gamma$. To each such space we associate a graph and a finite family of pairs of hyperbolic surfaces with cone singularities. We show that this data is sufficient to recover the space locally (i.e., in the neighborhood of a fixed metric). This is a partial extension of a result of Mess for non-singular globally hyperbolic AdS manifolds.Comment: 29 pages, 3 figures. v2: 41 pages, improved exposition. To appear, Comm. Math. Phys. arXiv admin note: text overlap with arXiv:0905.182

Fuchsian convex bodies: basics of Brunn--Minkowski theory

The hyperbolic space \H^d can be defined as a pseudo-sphere in the $(d+1)$ Minkowski space-time. In this paper, a Fuchsian group $\Gamma$ is a group of linear isometries of the Minkowski space such that \H^d/\Gamma is a compact manifold. We introduce Fuchsian convex bodies, which are closed convex sets in Minkowski space, globally invariant for the action of a Fuchsian group. A volume can be associated to each Fuchsian convex body, and, if the group is fixed, Minkowski addition behaves well. Then Fuchsian convex bodies can be studied in the same manner as convex bodies of Euclidean space in the classical Brunn--Minkowski theory. For example, support functions can be defined, as functions on a compact hyperbolic manifold instead of the sphere. The main result is the convexity of the associated volume (it is log concave in the classical setting). This implies analogs of Alexandrov--Fenchel and Brunn--Minkowski inequalities. Here the inequalities are reversed

Spatially variable fault friction derived from dynamic modeling of aseismic afterslip due to the 2004 Parkfield earthquake

We investigate fault friction from dynamic modeling of fault slip prior to and following the Mw 6.0 earthquake which ruptured the Parkfield segment of the San Andreas Fault in 2004. The dynamic modeling assumes a purely rate-strengthening friction law, with a logarithmic dependency on sliding rate: μ=μ *+a-blnvv*. The initial state of stress is explicitly taken into account, and afterslip is triggered by the stress change induced by the earthquake source model given a priori. We consider different initial stress states and two coseismic models, and invert for the other model parameters using a nonlinear inversion scheme. The model parameters include the reference friction μ*, the friction rate dependency characterized by the quantity a-b, assumed to be either uniform or depth dependent. The model parameters are determined from fitting the transient postseismic geodetic signal measured at continuous GPS stations. Our study provides a view of frictional properties at the kilometers scale over the 0-15 km depth illuminated by the coseismic stress change induced by the Parkfield earthquake. The reference friction is estimated to be between 0.1 and 0.5. With independent a priori constraints on the amplitude of differential stress, the range of possible values narrows down to 0.1-0.17. The friction rate coefficient a-b is estimated to be � 10- 3 - 10- 2 with a hint that it increases upward from about 1-3 � 10-3 at 3-7 km depth to about 4-7 � 10-3 at 0-1 km depth. It is remarkable that our results are consistent with frictional properties measured on rock samples recovered from the fault zone thanks to the San Andreas Fault Observatory at Depth experiment. ©2013. American Geophysical Union. All Rights Reserved