Global controllability tests for geometric hybrid control systems

Hybrid systems are characterized by having an interaction between continuous dynamics and discrete events. The contribution of this paper is to provide hybrid systems with a novel geometric formulation so that controls can be added. Using this framework we describe some new global controllability tests for hybrid control systems exploiting the geometry and the topology of the set of jump points, where the instantaneous change of dynamics take place. Controllability is understood as the existence of a feasible trajectory for the system joining any two given points. As a result we describe examples where none of the continuous control systems are controllable, but the associated hybrid system is controllable because of the characteristics of the jump set.Comment: 27 pages, 5 figure

Stochastic amplification of fluctuations in cortical up-states

Supporting Information: Appendix S1-S7Cortical neurons are bistable; as a consequence their local field potentials can fluctuate between quiescent and active states, generating slow 0.5-2 Hz oscillations which are widely known as transitions between Up and Down States. Despite a large number of studies on Up-Down transitions, deciphering its nature, mechanisms and function are still today challenging tasks. In this paper we focus on recent experimental evidence, showing that a class of spontaneous oscillations can emerge within the Up states. In particular, a non-trivial peak around 20 Hz appears in their associated power-spectra, what produces an enhancement of the activity power for higher frequencies (in the 30-90 Hz band). Moreover, this rhythm within Ups seems to be an emergent or collective phenomenon given that individual neurons do not lock to it as they remain mostly unsynchronized. Remarkably, similar oscillations (and the concomitant peak in the spectrum) do not appear in the Down states. Here we shed light on these findings by using different computational models for the dynamics of cortical networks in presence of different levels of physiological complexity. Our conclusion, supported by both theory and simulations, is that the collective phenomenon of >stochastic amplification of fluctuations> - previously described in other contexts such as Ecology and Epidemiology - explains in an elegant and parsimonious manner, beyond model-dependent details, this extra-rhythm emerging only in the Up states but not in the Downs. © 2012 Hidalgo et al.Funding provided by Spanish MICINN-FEDER under project FIS2009-08451 and Junta de Andalucia Proyecto de Excelencia P09FQM-4682. L.S. acknowledges the financial support of Fundacion P. Barrie de la Maza and funding grant 01GQ1001A.Peer Reviewe

What knowledge and conceptions mobilize future teachers analyzing a classroom video?

El uso del vídeo de sesiones de clase de Educación Primaria (EP) en la formación inicial del maestro aporta realismo a las discusiones teóricas de las aulas de magisterio, contribuyendo a la vinculación entre la teoría y la práctica sobre la base de procesos reflexivos que ayudan a trascender los habituales comentarios genéricos de los estudiantes para maestro (EPM). El objetivo de este estudio es identificar las concepciones sobre la enseñanza y el aprendizaje de las matemáticas así como el conocimiento matemático para la enseñanza (particularmente el conocimiento de matemáticas y la enseñanza y el conocimiento de matemáticas y los estudiantes) que un grupo de EPM pone en juego cuando observa un vídeo de EP. Mediante un diseño de investigación consistente con un experimento de enseñanza (Steffe y Thompson, 2000) (en el que un diseño instruccional, orientado a los EPM, acerca de la introducción del concepto de división, se va refinando a través de sucesivos ciclos de implementación y análisis), se pone de relieve cómo el análisis de situaciones de enseñanza en EP promueve el cuestionamiento de los EPM.The use of the Primary Education (PE) class sessions video in the initial training of teachers provides realism to the theoretical discussions of Master’s degree classrooms, contributing to the link between theory and practice on the basis of reflective processes that help to transcend the normal general comments of teacher students (TS). The objective of this study is to identify the conceptions for the teaching and learning of mathematics, as well as the mathematical knowledge for teaching (particularly the knowledge of mathematics and the teaching and knowledge of mathematics and students) that a group of TS use when observing a PE video. Using a research design consistent with a teaching experiment (Steffe and Thompson, 2000) (in which an instructional design, aimed at TS, regarding the introduction of the concept of division, is refined by means of successive cycles of implementation and analysis), the way the analysis of teaching situations in PE promotes the questioning of TS is highlighted.O uso de vídeos de sessões de aula de Educação Primária (EP) na formação inicial do professor oferece realismo às discussões teóricas sobre as aulas de magistério, contribuindo para a vinculação entre a teoria e a prática sobre a base de processos reflexivos que ajudam a transcender os habituais comentários genéricos dos estudantes para professores (EPM). O objetivo deste estudo é identificar as concepções sobre o ensino e a aprendizagem da matemática, assim como o conhecimento matemático para o ensino (particularmente o conhecimento de matemática e o ensino e o conhecimento de matemática e dos estudantes) que um grupo de EPM põe em jogo quando observa a um vídeo de EP. Através de uma criação de pesquisa consistente com um experimento de ensino (Steffe e Thompson, 2000), destaca-se como a análise de situações de ensino em EP promove o questionamento dos EPM.L’utilisation de la vidéo pour une classe d’élèves en école primaire (EP) durant la formation des futurs instituteurs confère un certain réalisme aux discussions théoriques qui ont lieu dans les cours de formation des instituteurs (l’équivalent en France des IUFM) en contribuant à la création de liens entre théorie et pratique basés sur des processus réflexifs qui permettent aux étudiants d’aller au-delà des habituels commentaires généraux. L’objectif de la présente étude consiste à identifier les conceptions sur l’enseignement et l’apprentissage des mathématiques ainsi qu’à s’interroger sur la connaissance mathématique pour l’enseignement (en particulier, la connaissance des mathématiques et l’enseignement des mathématiques et les étudiants) qu’un groupe de futurs instituteurs utilise lorsqu’il observe une vidéo conçue pour l’école primaire. Grâce à un travail de recherche qui va de pair avec une expérience sur l’enseignement (Steffe et Thompson, 2000) (dans lequel un travail propre à l’enseignement conçu pour les futurs instituteurs portant sur l’introduction du concept de division s’affine de plus en plus au fur et à mesure que des cycles successifs de mises en oeuvre et d’analyse sont utilisés), on montre comment l’analyse de situations en école primaire suscite le questionnement des futurs instituteurs

Allelic Diversity at Abiotic Stress Responsive Genes in Relationship to Ecological Drought Indices for Cultivated Tepary Bean, Phaseolus acutifolius A. Gray, and Its Wild Relatives

Some of the major impacts of climate change are expected in regions where drought stress is already an issue. Grain legumes are generally drought susceptible. However, tepary bean and its wild relatives within Phaseolus acutifolius or P. parvifolius are from arid areas between Mexico and the United States. Therefore, we hypothesize that these bean accessions have diversity signals indicative of adaptation to drought at key candidate genes such as: Asr2, Dreb2B, and ERECTA. By sequencing alleles of these genes and comparing to estimates of drought tolerance indices from climate data for the collection site of geo-referenced, tepary bean accessions, we determined the genotype x environmental association (GEA) of each gene. Diversity analysis found that cultivated and wild P. acutifolius were intermingled with var. tenuifolius and P. parvifolius, signifying that allele diversity was ample in the wild and cultivated clade over a broad sense (sensu lato) evaluation. Genes Dreb2B and ERECTA harbored signatures of directional selection, represented by six SNPs correlated with the environmental drought indices. This suggests that wild tepary bean is a reservoir of novel alleles at genes for drought tolerance, as expected for a species that originated in arid environments. Our study corroborated that candidate gene approach was effective for marker validation across a broad genetic base of wild tepary accessions

Bgs1p is responsible for primary septum formation

[EN]Cytokinesis is a crucial event in the cell cycle of all living cells. In fungal cells, it requires coordinated contraction of an actomyosin ring and synthesis of both plasmatic membrane and a septum structure that will constitute the new cell wall end. Schizosaccharomyces pombe contains four essential putative (1,3)β-D-glucan synthase catalytic subunits, Bgs1p to Bgs4p. Here we examined the function of Bgs1p in septation by studying the lethal phenotypes of bgs1 + shut-off and bgs1 Δ cells and demonstrated that Bgs1p is responsible and essential for linear (1,3)β-D-glucan and primary septum formation. bgs1 + shut-off generates a more than 300-fold Bgs1p reduction, but the septa still present large amounts of disorganized linear (1,3)β-D-glucan and partial primary septa. Conversely, both structures are absent in bgs1 Δ cells, where there is no Bgs1p. The septum analysis of bgs1+-repressed cells indicates that linear (1,3)β-D-glucan is necessary but not sufficient for primary septum formation. Linear (1,3)β-D-glucan is the polysaccharide that specifically interacts with the fluorochrome Calcofluor white in fission yeast. We also show that in the absence of Bgs1p abnormal septa are formed, but the cells cannot separate and eventually die

Intravitreal, retinal, and central nervous system foscarnet concentrations after rapid intravenous administration to rabbits

Retinal, vitreous humor, brain, and cerebrospinal fluid (CSF) foscarnet levels were measured by high-performance liquid chromatography after administration of an intravenous dose of 120 mg/kg of body weight to 32 pigmented rabbits. A pharmacokinetic analysis was done using a two- compartment model. The penetration ratios, defined as ratios of retinal, vitreous humor, brain, and CSF areas under the concentration-time curve from 0 to 2 h were 110% ± 1%, 12.3% ± 0.7%, 118% ± 1%, and 20.2% ± 2.2%, respectively. These results suggest a good penetration of foscarnet into the retinal and brain tissues, reaching higher concentrations than those estimated from vitreous humor and CSF levels.Comisóión Interministerial de Ciencia y Tecnología SAF97-0012Consejería de Salud Junta de Andalucía 64/9

The materials production and processing facility at the Spanish National Centre for fusion technologies (TechnoFusión)

Proceedings of : The 26th Symposium of Fusion Technology (SOFT-26), Porto (Portugal),- 27 september - 1 october 2010.In response to the urgent request from the EU Fusion Program, a new facility (TechnoFusion) for research and development of fusion materials has been planned with support from the Regional Government of Madrid and the Ministry of Science and Innovation of Spain. TechnoFusion, the National Centre for Fusion Technologies, aims screening different technologies relevant for ITER and DEMO environments while promoting the contribution of international companies and research groups into the Fusion Programme. For this purpose, the centre will be provided with a large number of unique facilities for the manufacture, testing (a triple-beam multi-ion irradiation, a plasma-wall interaction device, a remote handling for under ionizing radiation testing) and analysis of critical fusion materials. Particularly, the objectives, semi-industrial scale capabilities and present status of the TechnoFusion Materials Production and Processing (MPP) facility are presented. Previous studies revealed that the MPP facility will be a very promising infrastructure for the development of new materials and prototypes demanded by the fusion technology and therefore some of them will be here briefly summarized.This work has been supported by Madrid Community through the project TECHNOFUSION (S2009/ENE/1679).Publicad