Excitable optical waves in semiconductor microcavities

4 pages, 4 figures.-- PACS nrs.: 05.45.-a, 42.65.Sf, 42.65.Tg.-- PMID: 15783966 [PubMed].We demonstrate experimentally and theoretically the existence of excitable optical waves in semiconductor microcavities. Although similar to those observed in biological and chemical systems, these excitable optical waves are self-confined. This is due to a new dynamical scenario, where a stationary Turing pattern controls the propagation of waves in an excitable medium, thus bringing together the two paradigms of dynamical behavior (waves and patterns) in active media.We acknowledge financial support from MCYT (Spain) through project TIC2002-04255-C04-03 and European project VISTA.Peer reviewe

Snow avalanche susceptibility in the eastern hillside of the Aramo Range (Asturian Central Massif, Cantabrian Mountains, NW Spain)

A detailed snow avalanche susceptibility map of the eastern hillside in the Aramo Range (Cantabrian Mountains) is presented at a scale of 1:25,000. The Aramo Range is one of the major middle-altitude mountains of the Asturian Central Massif. Although it has of moderate height (maximum altitude of 1791 m a.s.l.), its eastern slope presents unusual snow avalanche activity. Specifically, a hundred of snow avalanche tracks have been mapped based on meticulous fieldwork and supported by interviews with local people, searches in newspaper archives, photointerpretation, and calculations based on the digital terrain model and geographic information system. As a result, a susceptibility map has been elaborated, which shows the suitability of combining fieldwork and geographic information technology. The composition consists of two maps that detail how the susceptibility mapping is obtained. The section analysed is limited to the eastern slope of the Aramo Range, whose total surface area is 1555.62 ha

Chaotically spiking canards in an excitable system with 2D inertial fast manifolds

PACS:05.45.−a, 42.65.−k, 42.65.SfWe introduce a new class of excitable systems with two-dimensional fast dynamics that includes inertia. A novel transition from excitability to relaxation oscillations is discovered where the usual Hopf bifurcation is followed by a cascade of period doubled and chaotic small excitable attractors and, as they grow, by a new type of canard explosion where a small chaotic background erratically but deterministically triggers excitable spikes. This scenario is also found in a model for a nonlinear Fabry-Perot cavity with one pendular mirror.This work was partially funded by the European Union ILIAS Project (No. RII3-CT-2003-506222), the CSIC— Spain Grant HIELOCRIS (No. 200530F0052).Peer reviewe

Dynamical mechanism of anticipating synchronization in excitable systems

We analyze the phenomenon of anticipating synchronization of two excitable systems with unidirectional delayed coupling which are subject to the same external forcing. We demonstrate for different paradigms of excitable system that, due to the coupling, the excitability threshold for the slave system is always lower than that for the master. As a consequence the two systems respond to a common external forcing with different response times. This allows to explain in a simple way the mechanism behind the phenomenon of anticipating synchronization.Comment: 4 pages including 7 figures. Submitted for publicatio

El patrimonio vegetal en los Arribes del Duero zamoranos: las formaciones de enebral Juniperus oxycedrus L. subsp. badia (H. Gay) Debeaux

Se analiza el patrimonio vegetal de los Arribes del Duero zamoranos, en concreto, las diferentes formaciones que componen el tapiz vegetal, empleando una metodología que combina el trabajo de campo (inventarios de vegetación, encuestas, localización y delimitación vía GPS y cartografía in situ), la fotointerpretación y la implementación de un Sistema de Información Geográfica. De todas las comunidades del paisaje vegetal sobresalen, por su singularidad, los enebrales de Juniperus oxycedrus L. subsp. badia (H. Gay) Debeaux, por cuanto que configuran inusuales masas muy densas y de porte arbóreo. Se trata, en efecto, de verdaderas manchas boscosas situadas en Cozcurrita y Mámoles (municipio de Fariza), que ocupan una superficie de 42,9 ha acompañadas de masas arborescentes en clara expansión colonizadora (252 ha), merced a la tendencia xerotérmica del clima y el abandono de las actividades agrosilvopastoriles tradicionales. En definitiva,los Arribes del Duero zamoranos disponen de un rico patrimonio vegetal que se concreta en 4 hábitats forestales de interés comunitario que abarcan una extensión de 1.795 ha, la cual representa el 30,1% del territorio. De esta categoría quedan fuera los enebrales de Juniperus oxycedrus subsp. badia, incluidos, sin embargo, en el tipo 5210 de matorrales arborescentes de Juniperus spp., pese a tratarse de bosques de alto valor natural y cultural

El paisaje vegetal y los hábitats forestales de interés comunitario en la Montaña Central Asturiana

Se estudia el paisaje vegetal y los hábitats forestales de interés comunitario en dos sectores de la Montaña Central Asturiana: el Alto Pajares, un valle de alta montaña que ha experimentado importantes transformaciones paisajísticas debido al declive del modelo de sociedad rural y a la construcción de equipamientos e infraestructuras como la estación de esquí Valgrande-Pajares y la autopista del Huerna; y la Sierra del Aramo, una alineación calcárea de media montaña, de vocación tradicional ganadera, que configura desde el punto de vista biogeográfico, a tenor de criterios florísticos y atendiendo a las comunidades y series de vegetación presentes, una bisagra biogeográfica entre las subprovincias Cantabro-atlántica y Orocantábrica dentro de la provincia Atlántica-Europea de la región Eurosiberiana. Sendas zonas de montaña se caracterizan por su elevado patrimonio vegetal, en concreto, la Sierra del Aramo cuenta con 7 hábitats de interés comunitario que abarcan una superficie de 2.235 ha, esto es, más del 28% de su superficie forestal; mientras que el Alto Pajares, si bien sólo dispone de 3 hábitats, no obstante, alcanzan una extensión de 1.105,49 ha, lo que representa más del 70% de su área boscosa

Rethinking Schizophrenia in the Context of the Person and Their Circumstances: Seven Reasons

We know a great deal about schizophrenia, but the current state of the art is one of uncertainty. Researchers are confused, and patients feel misunderstood. This situation has been identified as due largely to the fact that the dominant neurobiological perspective leaves out the person. The aim of the present article is to review and integrate a series of clinical, phenomenological, historical, cultural, epidemiological, developmental, epigenetic and therapeutic phenomena in support of a suggestion that schizophrenia is above all a disorder of the person rather than of the brain. Specifically, we review seven phenomena, beginning with the conception of schizophrenia as a particular disorder of the self. We continue by looking at its recent origin, as a modern phenomenon, its juvenile onset, related to the formation of the self, the better prognosis in developing countries compared to developed countries, and the high incidence of the disorder among migrants. In the context of these phenomena of a marked socio-cultural nature, we consider the so-called genetic myth, according to which schizophrenia would have a genetic origin. On reviewing the current genetic emphasis in the light of epigenetics, it emerges that the environment and behaviour recover their prominent role in the vicissitudes of development. The seventh reason, which closes the circle of the argument, concerns the role of interpersonal chemistry in recovery of the sense of self

Capacitor voltage balance limits in a multilevel-converter-based energy storage system

This paper studies an energy storage system based on a three-level DC-DC converter and a gridconnected neutral-point-clamped inverter. The main advantages of this multilevel power conversion system are highlighted and the neutral-point voltage oscillations are analyzed. A modulation algorithm for the DC-DC converter which includes the neutral-point voltage balance control is used to improve the voltage balancing capabilities of the inverter. Some figures are presented to show the extended operating areas without neutral-point voltage oscillations thanks to the contribution of the DC-DC converter to the voltage balance. Finally, some guidelines to size the DC-link capacitors are given for a practical application.Peer ReviewedPostprint (published version

Piezoelectric Nanomaterials Activated by Ultrasound: The Pathway from Discovery to Future Clinical Adoption

Electrical stimulation has shown great promise in biomedical applications, such as regenerative medicine, neuromodulation, and cancer treatment. Yet, the use of electrical end effectors such as electrodes requires connectors and batteries, which dramatically hamper the translation of electrical stimulation technologies in several scenarios. Piezoelectric nanomaterials can overcome the limitations of current electrical stimulation procedures as they can be wirelessly activated by external energy sources such as ultrasound. Wireless electrical stimulation mediated by piezoelectric nanoarchitectures constitutes an innovative paradigm enabling the induction of electrical cues within the body in a localized, wireless, and minimally invasive fashion. In this review, we highlight the fundamental mechanisms of acoustically mediated piezoelectric stimulation and its applications in the biomedical area. Yet, the adoption of this technology in a clinical practice is in its infancy, as several open issues, such as piezoelectric properties measurement, control of the ultrasound dose in vitro, modeling and measurement of the piezo effects, knowledge on the triggered bioeffects, therapy targeting, biocompatibility studies, and control of the ultrasound dose delivered in vivo, must be addressed. This article explores the current open challenges in piezoelectric stimulation and proposes strategies that may guide future research efforts in this field toward the translation of this technology to the clinical scene

Aplicación de la terapia contextual basada en la persona a un caso complejo de esquizofrenia

Antecedentes: las terapias psicológicas están siendo cada vez más importantes en la esquizofrenia, y no como meras adjuntas a la medicación. La psicoterapia de la esquizofrenia está cobrando nueva vida a la luz de desarrollos fenomenológicos y psicológicos centrados en la persona. Método: se presenta un caso complejo, de abigarrada sintomatología y larga duración, sin que hasta ahora la medicación produjera cambios clínicos significativos. La formulación del caso de acuerdo con la terapia cognitiva basada en la persona permitió entender los síntomas psicóticos en el contexto biográfico y llevar a cabo una terapia centrada en la recuperación del sentido del yo y de la vida. Resultados: al final de la terapia y en el seguimiento de un año las experiencias psicóticas habían desaparecido prácticamente o dejado de ser perturbadoras y la paciente se había reintegrado en la vida social. Conclusiones: los síntomas psicóticos cobran sentido en el contexto biográfico. Esto puede servir a la explicación psicopatológica y a una ayuda terapéutica significativa, más centrada en la recuperación que en el mero sostenimiento, que fácilmente termina en "abandono" asistencial y existencial. La terapia psicológica muestra ser viable en casos complejos atendidos en dispositivos públicos.Background: Psychological therapies are becoming more and more important in schizophrenia, and not as mere adjuncts to medication. The psychotherapy of schizophrenia is taking on a new lease of life in the wake of person-based phenomenological and psychological developments. Method: The case in question was a complex one, with variegated symptomatology that had persisted over many years. Approaching the case from the perspective of person-based cognitive therapy allowed us to understand the psychotic symptoms in the biographical context and to apply a therapy focused on the patient's recovery of her sense of self and of life. Results: At the end of the therapy and throughout the 12-month follow-up, the psychotic experiences had practically disappeared, or ceased to be disturbing, and the patient had become re-integrated in social life. Conclusions: Psychotic symptoms take on meaning in the biographical context. Adopting this perspective can aid the psychopathological explanation of the disorder and provide significant therapeutic help, more focused on recovery. Psychological therapy has shown itself to be viable in complex cases treated within the public-sector healthcare context