Tracking the oxygen isotopic signature from the rainfall to the speleothems in Ortigosa de Cameros caves (La Rioja, Spain)

A one-year monitoring survey has been carried out in La Paz and La Viña Caves in the Ortigosa de Cameros Cave System (NE Iberian Peninsula), in order to track the oxygen isotope signal from rainfall to speleothem calcite, assessing the ability of this signal to retain environmental information. Oxygen isotope signals of rainfall events, drip water —sampled every three months—, and speleothem calcite, precipitated over three-months, are compared. Water dripping follows precipitation events in winter, spring and summer, more closely in the near-surface drip points than in the deeper ones. In autumn, dripping is delayed with respect to rainfall, suggesting that water stays in the epikarst before dripping resumes after summer. This delay causes a deviation of the total drip water signal (average δ¹⁸O=−8.39‰ V-SMOW) from the rainfall signal (average δ¹⁸O=−7.41‰ V-SMOW). On the contrary, in winter the isotopic signal of drip water keeps the rainfall signal. Calcite isotopic signal (total average δ¹⁸O=−6.83‰ V-PDB) shows a small offset (0.62–0.75%) with respect to the signal predicted by drip water oxygen composition; this points to a limited kinetic effect in calcite precipitation, therefore calcite retains the signal of rainfall, especially in winter.<br><br>Durante un año se han monitorizado las cuevas de La Paz y La Viña en el Sistema de Cuevas de Ortigosa de Cameros (NE de la Península Ibérica) para rastrear la señal isotópica del oxígeno desde la lluvia a la calcita espeleotémica, y así valorar la capacidad de esta señal para conservar información medioambiental. Se han comparado las señales isotópicas del oxígeno de los eventos de la lluvia, el agua de goteo (muestreada trimestralmente) y la calcita espeleotémica, precipitada también durante cada trimestre. El goteo en las cuevas responde a la precipitación en invierno, primavera y verano, más estrechamente en los puntos más próximos a la superficie que en los profundos. En otoño hay un retraso entre la lluvia y el goteo, lo que sugiere que el agua permanece por un tiempo en el epikarst, antes de que se reanude el goteo después del verano. Este retraso provoca que la señal isotópica del agua de goteo (media total de δ¹⁸O=−8.39‰ V-SMOW) se desvíe de la señal de la lluvia (media de δ¹⁸O=−7,41‰ V-SMOW). Por el contrario, en invierno la señal isotópica del agua de goteo es muy semejante a la de la lluvia. La composición isotópica de la calcita espeleotémica (media total de δ¹⁸O=−6,83‰ V-PDB) presenta un pequeño desfase (0,62–0,75%) respecto al valor que le correspondería por la composición isotópica del agua de goteo; esto indica que los efectos cinéticos durante la precipitación de la calcita son limitados, por lo que ésta conserva la señal de la lluvia, especialmente en invierno

Dise?o e implementaci?n del mundo caim?n del videojuego jaguares, que da a conocer la morfolog?a, uso y significado de la cer?mica de los ancestros del Tolima.

98 p. Recurso Electr?nicoDurante d?cadas, el Museo Antropol?gico de la Universidad del Tolima y el grupo GRAPA (Grupo de Investigaci?n en Arqueolog?a y Patrimonio Regional) han realizado investigaciones arqueol?gicas a lo largo del territorio tolimense, logrando hallazgos f?siles de animales y vegetales, adem?s de elementos cer?micos que datan desde 10.000 a.C. hasta la conquista y colonia espa?ola. Sin embargo, las nuevas generaciones se muestran indiferentes ante los conocimientos obtenidos. Este proyecto busca crear un videojuego para ense?ar de manera novedosa, a ni?os con edades entre ocho a catorce a?os sobre las cer?micas tolimenses. Se implementa sobre Unity v5.5.1f1, aplicando la metodolog?a de desarrollo ?gil SUM que se adapta para la creaci?n de videojuegos utilizando roles de SCRUM, e incorpora seis fases consecutivas que son: concepto, planificaci?n, elaboraci?n, beta, cierre y gesti?n de riesgos que se realiza de manera continua durante la ejecuci?n del desarrollo. Durante la fase de concepto se realiza una investigaci?n amplia sobre la cer?mica tolimense, que posteriormente sirve como insumo para crear una propuesta detallada y s?lida en la etapa de planificaci?n. En la fase de elaboraci?n se aplica la metodolog?a de Arquitectura Dirigida por Modelos (MDA) orientada a la elaboraci?n de videojuegos. Esta fase se realiza de manera iterativa y en conjunto con las pruebas Beta que permiten evaluar el cumplimiento de los objetivos planteados a medida que se avanza en el desarrollo. Por ?ltimo en la fase de cierre se generan los productos finales y se eval?an las lecciones aprendidas. Palabras claves: Unity, Videojuego 2D, Videojuego Educativo, Metodolog?a SUM, Museo Antropol?gico, Cer?mica tolimense.For decades, the Anthropological Museum of the University of Tolima and the group GRAPA (Research Group in Archeology and Regional Heritage) have carried out archaeological research throughout the territory of Tolima, finding fossil of animals and plants, as well as ceramic elements dating back to from 10,000 BC until the Spanish conquest and colony. However, the new generations are indifferent to the knowledge obtained. This project seeks to create a video game to teach in a novel way, to children aged between eight and fourteen years old, about the ceramics of Tolima. It is implemented on Unity v5.5.1f1, applying the agile development methodology SUM that is adapted for the creation of video games using SCRUM roles, and incorporates six consecutive phases that are: concept, planning, preparation, beta, closure and risk management that is done continuously during the execution of the development. During the concept phase, a comprehensive investigation is carried out on ceramic of Tolima, which later serves as an input to create a detailed and solid proposal in the planning stage. In the elaboration phase, the methodology of Model-Directed Architecture (MDA), oriented to the elaboration of videogames is applied. This phase is carried out iteratively and in conjunction with Beta tests that allow evaluating compliance with the objectives set as progress is made in development. Finally, in the closing phase, the final products are generated and the lessons learned are evaluated. Keywords: Unity, 2D Videogame, Educational Videogame, SUM Methodology, Anthropological Museum, Tolima?s Ceramics

Diagn?stico de la situaci?n de convivencia escolar de la instituci?n educativa

138 P?ginasRecurso Electr?nicoEsta investigaci?n se realiza con el objeto de diagnosticar la situaci?n de convivencia escolar en la instituci?n educativa colegio de San Sim?n teniendo en cuenta las particularidades del clima escolar y de las caracter?sticas familiares, sociales, econ?micas y culturales externas que inciden en las relaciones interpersonales del grado sexto. El estudio se realiz? a partir de tres dimensiones que afectan la convivencia escolar. La primera son las caracter?sticas propias del estudiante y la disposici?n que tienen para vivir en sociedad bajo condiciones de respeto, solidaridad, tolerancia e inclusi?n. La segunda dimensi?n tiene que ver con las condiciones particulares de la instituci?n educativa y los aspectos relacionados con las situaciones sucedidas al interior del colegio, agresiones f?sicas, verbales, ofensas, golpes, pelea, armas, robos, vandalismos e incidentes de tipo sexual. Por ?ltimo, el entorno familiar y de barrio en donde se incluyen los amigos y situaciones de riesgo presentes, pandillas, alcohol y drogas e incidentes de ida y vuelta al colegio. Siguiendo ?ste an?lisis, se presentan los resultados de la investigaci?n, iniciando con la estructura y caracterizaci?n de la poblaci?n de estudio. Se contin?a con las circunstancias que podr?an afectar el clima escolar y que se encuentran relacionadas con el colegio, finalmente se exponen los factores asociados al entorno de barrio que inciden directamente en la convivencia escolar.ABSTRACT. The study was conducted from three dimensions affect school life. The first are the characteristics of the student and the willingness they have to live in society under conditions of respect, solidarity, tolerance and inclusion. The second dimension has to do with the particular conditions of the educational stablishment and aspects events situations within the school, physical aggression, verbal insults, beatings, fights, weapons, theft, vandalism and incidents of a sexual nature. Finally, the family and neighborhood environment where friends and present risk situations, gangs, alcohol and drugs, incidents and from the school are included. In order to identify the risk of occurrence of the most common conditions affecting school life , from the particularities of the school climate and family , economic and external cultural characteristics that affect relationships sixth grade. Following this analysis, the results of the research are presented, starting with the structure and characterization of the study population. It continues with the circumstances that could affect school climate and that are related to school factors associated finally exposed to neighborhood environment that directly affect school life.INTRODUCCI?N 14 1. PLANTEAMIENTO DEL PROBLEMA 19 2. JUSTIFICACI?N 22 2.1 PREGUNTAS DE INVESTIGACION 24 3. OBJETIVOS 25 3.1 OBJETIVO GENERAL 25 3.2 OBJETIVOS ESPEC?FICOS 25 4. MARCO DE REFERENCIA 26 4.1 CONVIVENCIA 26 4.2 CONVIVENCIA ESCOLAR 28 4.3 CLIMA ESCOLAR 30 4.3.1 Violencia y conflicto escolar 31 4.4 FACTORES DE RIESGO DE CONVIVENCIA 35 4.5 FACTORES DE RIESGO PERSONAL 37 4.6 FACTOR DE RIESGO FAMILIAR 39 4.7 FACTORES DE RIESGOS DE CONTEXTO 41 4.8 CONDUCTAS QUE AFECTAN LA CONVIVENCIA ESCOLAR. 46 4.9 LOS VALORES Y LAS NORMAS 48 4.10 MARCO LEGAL 51 5. DISE?O METODOL?GICO 57 5.1 CARACTER?STICAS GENERALES DE LA INVESTIGACI?N 57 5.2 POBLACI?N Y MUESTRA 57 5.3 TAMA?O DE LA MUESTRA 58 5.3.1 Composici?n de estudiantes por grados, jornada ma?ana y tarde 58 5.4 INSTRUMENTOS 59 6. RESULTADOS 62 6.1 OFENSAS Y GOLPES EN EL COLEGIO 62 6.1.2 Peleas en el colegio. 68 6.1.3 Porte de armas de fuego. 70 6.1.4 Robos y vandalismo en el colegio. 72 6.1.5 Agresiones repetidas en el colegio. 73 6.1.6 Incidentes de tipo sexual en el colegio. 75 6.1.7 Armas de fuego 78 6.1.8 Armas en el colegio 79 6.1.9 Incidentes en el camino de Ida o vuelta de tu Colegio. 81 6.1.10 Entornos 85 6.1.11 Pandillas 92 6.1.12 Alcohol y drogas 96 6.1.13 Seguridad y confianza 102 6.1.14 Actitudes y competencias 104 6.1.15 Actitudes y competencias 105 6.1.16 Entorno familiar 116 7. CONCLUSIONES 119 7.1 ESTRATEGIAS 123 7.1.1 Estrategias para prevenir el conflicto y la violencia escolar 123 7.2 APORTES CONCEPTUALES 126 7.2.1 Riesgo de convivencia. 127 7.2.2 Factor de riesgo de convivencia 127 7.2.3 Factor de riesgo personal 127 7.2.4 Factor de riesgo interno 127 7.2.5 Factor de riesgo externo 128 7.2.5.1 Valoraci?n de riesgo 128 7.2.5.2 Mapa de factores de riesgo 128 RECOMENDACIONES 129 REFERENCIAS 13

El Catatumbo: estrategia militar por encima de desarrollo rural. Estudio de caso: Víctor Ramón Navarro Serrano, alias Megateo

The Catatumbo region is linked to the history of military conflict and coca plant cultivation in&nbsp;Colombia. This reflection paper carries out a case study on the socio-economic influence of&nbsp;Víctor Ramón Navarro Serrano, alias Megateo, a commander of the Ejército Popular de&nbsp;Liberación, EPL, (Popular Liberation Army) in the region. His persecution and death were tied&nbsp;to a militaristic strategy, consistent with the distinguishing type of State’s presence, this&nbsp;demonstrates that the warlike approach has greater relevance than the territorial rural development. Governments’ actions have focused on major deployment of public force, by&nbsp;unknown the complex realities and basic needs of the population. Dynamics in Catatumbo region&nbsp;has been a barrier to develop territorial rural development policies, on account of this requires&nbsp;presence of state institutions which support the initiatives of local stakeholders. It can be&nbsp;observed that the militarization of the region has had as a result the stigmatization of actors and&nbsp;social organizations as well as ruptures between them and the State, which prevents the&nbsp;generation of real alternatives for replacement of coca cultivation.La región del Catatumbo está ligada a la historia del conflicto militar y el cultivo de coca en&nbsp;Colombia. El artículo de reflexión realiza un estudio de caso sobre la influencia socio-económica de Víctor Ramón Navarro Serrano, alias Megateo, mando del Ejército Popular de&nbsp;Liberación (EPL) en la región. Su persecución y muerte estuvieron atadas a una estrategia&nbsp;militarista, acorde con la presencia de tipo diferencial del Estado; esto demuestra que elenfoque bélico presenta mayor relevancia que el desarrollo rural territorial. Las acciones de los&nbsp;gobiernos se han centrado en un mayor despliegue de la fuerza pública y han desconocido las&nbsp;realidades complejas y las necesidades básicas de la población. Las dinámicas del Catatumbo&nbsp;han sido una barrera para desarrollar políticas de desarrollo rural territorial, debido a que&nbsp;estas requieren presencia de las instituciones estatales que apoyen las iniciativas de los actores&nbsp;sociales locales. Se puede observar que la militarización de la región ha tenido como&nbsp;consecuencia la estigmatización de actores y organizaciones sociales, así como rupturas entreestos y el Estado, lo que impide la generación de alternativas reales para la sustitución del&nbsp;cultivo de la coca

Interactions Between the Serotonergic and Other Neurotransmitter Systems in the Basal Ganglia: Role in Parkinson's Disease and Adverse Effects of L-DOPA

Parkinson's disease (PD) is characterized by the progressive loss of dopaminergic neurons in the substantia nigra. However, other non-dopaminergic neuronal systems such as the serotonergic system are also involved. Serotonergic dysfunction is associated with non-motor symptoms and complications, including anxiety, depression, dementia, and sleep disturbances. This pathology reduces patient quality of life. Interaction between the serotonergic and other neurotransmitters systems such as dopamine, noradrenaline, glutamate, and GABA controls the activity of striatal neurons and are particularly interesting for understanding the pathophysiology of PD. Moreover, serotonergic dysfunction also causes motor symptoms. Interestingly, serotonergic neurons play an important role in the effects of L-DOPA in advanced PD stages. Serotonergic terminals can convert L-DOPA to dopamine, which mediates dopamine release as a "false" transmitter. The lack of any autoregulatory feedback control in serotonergic neurons to regulate L-DOPA-derived dopamine release contributes to the appearance of L-DOPA-induced dyskinesia (LID). This mechanism may also be involved in the development of graft-induced dyskinesias (GID), possibly due to the inclusion of serotonin neurons in the grafted tissue. Consistent with this, the administration of serotonergic agonists suppressed LID. In this review article, we summarize the interactions between the serotonergic and other systems. We also discuss the role of the serotonergic system in LID and if therapeutic approaches specifically targeting this system may constitute an effective strategy in PD

Pancreatic Exocrine Insufficiency as a Complication of Gastrointestinal Surgery and the Impact of Pancreatic Enzyme Replacement Therapy

BACKGROUND: Pancreatic exocrine insufficiency (PEI) is characterized by inadequate production, insufficient secretion, and/or inactivation of pancreatic enzymes, resulting in maldigestion. The aim of this review was to analyze the prevalence and pathophysiology of PEI resulting from gastrointestinal (GI) surgery and to examine the use of pancreatic enzyme replacement therapy (PERT) for effectively managing PEI. SUMMARY: A targeted PubMed search was conducted for studies examining the prevalence and pathophysiology of PEI in patients following GI surgery and for studies assessing the effects of PERT in these patients. PEI is a common complication following GI surgery that can lead to nutritional deficiencies, which may contribute to morbidity and mortality in patients. Timely treatment of PEI with PERT can prevent malnutrition, increase quality of life, and possibly reduce the associated mortality. Treatment of PEI should aim not only to alleviate symptoms but also to achieve significant improvements in nutritional parameters. Dose optimization of PERT is required for effective management of PEI, in addition to regular assessment of nutritional status, appropriate patient education, and reassessment if symptoms return. Key Messages: Difficulties in detecting PEI following GI surgery can result in undiagnosed and untreated maldigestion, leading to metabolic complications and increased morbidity. Both are preventable by early administration and monitoring for optimal doses of PERT

Herramienta pedag?gica para la ense?anza de las ciencias naturales

48 P?ginasRecurso Electr?nicoEl presente proyecto est? basado en la implementaci?n de una Herramienta Pedag?gica en el ?rea de las Ciencias Naturales en el grado s?ptimo (A, B y C) de la Instituci?n Escuela Normal Superior Santa Teresita. Esta instituci?n no cuenta con proyectos sobre las herramientas pedag?gicas, pero es de resaltar que la instituci?n es netamente pedag?gica y que se fundamenta en el pedagogo Celestin Freinet, el cual plantea el texto libre y la UAI. Teniendo en cuenta los Lineamientos curriculares, los cuales proponen ejes fundamentales como son los procesos de pensamiento y acci?n y conocimiento cient?fico b?sico, se realiza la Cartilla ?EXPLOREMOS 7?? ?La C?lula?, con el fin de que los estudiantes participen de un aprendizaje activo y significativo. Para la realizaci?n de este proyecto, las investigadoras se centraron en varios autores como Koock, Ville, Helena Curt?s, Sneider y Chowan, quienes dieron aportes significativos a esta tesis de grado. Con esta Herramienta Pedag?gica se busca mejorar los procesos de aprendizaje de los estudiantes, mejorando la actividad educativa evidenciando mediante la pr?ctica resultados positivos de aprendizaje.ABSTRACT. This project is based on the implementation of a Pedagogical Tool in the area of natural science in seventh grade (A, B and C) of the Superior Normal School Institution Theresa. This institution has no projects on educational tools, but it is noteworthy that the institution is purely educational and is based on the pedagogue Celestin Freinet, which raises the free text and IAU. Given the curriculum guidelines, which are proposed as the cornerstones of thought and action processes and basic scientific knowledge, the Primer is done "EXPLORATIONS 7th" "The Cell" in order to engage students in learning active and meaningful. For this project, the researchers focused on several authors as Koock, Ville, Helena Curtis, Sneider and Chowan, who gave significant contributions to this thesis. This pedagogical tool is to improve the learning processes of students, improving the educational activity showing positive results through practical learning.INTRODUCCI?N 11 1. MARCO CONTEXTUAL 12 2. ANTECEDENTES 13 3. FORMULACI?N DEL PROBLEMA 15 4. PREGUNTA PROBLEMATIZADORA 16 5. JUSTIFICACI?N 17 6. OBJETIVOS 18 6.1 OBJETIVO GENERAL 18 6.2 OBJETIVOS ESPEC?FICOS 18 7. MARCO TE?RICO 19 7.1 LEY GENERAL DE EDUCACI?N 19 7.2 LINEAMIENTOS Y EST?NDARES CURRICULARES 19 7.2.1 Procesos de pensamiento y acci?n grado s?ptimo 20 7.2.2 Conocimiento de procesos biol?gicos 20 7.3 CONSTRUCTIVISMO 21 7.4 DID?CTICA 21 7.5 ESTRATEGIA 22 7.6 ESTRATEGIAS DID?CTICAS 23 7.7 APRENDIZAJE SIGNIFICATIVO 23 7.8 ENSE?ANZA 26 7.9 PEDAGOG?AS ACTIVAS 26 7.10 CELESTIN FREINET 27 7.11 HELENA CURTIS 29 7.12 N. SUE BARNES 30 7.13 ADRIANA SCHNEK 30 8. DISE?O METODOL?GICO 31 8.1 TIPO DE INVESTIGACI?N 31 8.2 FASES DE LA INVESTIGACI?N 32 8.3 POBLACI?N 33 8.4 MUESTRA 33 8.5 CATEGOR?AS 33 8.6 INSTRUMENTOS PARA LA RECOLECCI?N DE INFORMACI?N 33 8.6.1 Observaci?n participativa 34 8.6.2 Taller 34 9. CRONOGRAMA DE ACTIVIDADES 35 10. AN?LISIS DE RESULTADOS 36 10.1 PRE-T?S TALLER DE DIAGN?STICO 36 10.2 POST-TEST. PRUEBA FINAL 37 10.3 AN?LISIS COMPARATIVO 39 10.3.1 Diferencias de la c?lula animal y la c?lula vegetal 39 10.3.2 Funciones de la c?lula animal y vegetal 39 11. CONCLUSIONES 41 RECOMENDACIONES 42 REFERENCIAS 43 ANEXOS 4

Differences in In Vitro Properties of Pancreatin Preparations for Pancreatic Exocrine Insufficiency as Marketed in Russia and CIS

BACKGROUND: Pancreatic enzyme-replacement therapy (PERT), provided as pancreatin to patients with pancreatic exocrine insufficiency (PEI), is considered an essential substitute for the pivotal physiological function the pancreas fulfills in digestion. PEI involves a reduction in the synthesis and secretion of pancreatic enzymes (lipase, protease, amylase), which leads to an inadequate enzymatic response to a meal and consequently to maldigestion and malabsorption of nutrients. The efficacy of PERT is strongly dependent on enzyme activity, dissolution, and pancreatin particle size. OBJECTIVE: The physiological properties of eight pancreatin preparations (nine batches; five different brands) available in Russia and CIS (Commonwealth of Independent States: Armenia, Azerbaijan, Belarus, Kazakhstan, Kyrgyzstan, Moldova, Russia, Tajikistan, Uzbekistan) were investigated. METHODS: The lipase activity, dissolution, and particle size distribution of samples from multiple batches of pancreatin of different strengths were measured. RESULTS: Regarding lipase activities, all pancreatin preparations except Micrazim(R) matched the labeled content. Considerable differences were observed in particle size and dissolution. CONCLUSION: Pancreatin preparations available in Russia and CIS demonstrate product-to-product and batch-to-batch variability regarding the measured properties of lipase activity, dissolution, and particle size. This may impact the efficacy of PERT and therefore clinical outcomes

Proceso de construcci?n de una cultura de paz en los ni?os de transici?n de la instituci?n educativa Armando Romero Lozano de Sevilla Valle, a trav?s de estrategias did?cticas sensibilizadoras

121 p. Recurso Electr?nicoEl presente proyecto de investigaci?n ?proceso de construcci?n de una cultura de paz en los ni?os de preescolar, a trav?s de estrategias did?cticas sensibilizadoras? consiste en visibilizar los alcances en la mejora de las habilidades de resoluci?n de conflictos a trav?s de actividades l?dicas y art?sticas en los ni?os de preescolar de Instituci?n Educativa Armando Romero Lozano del municipio de Sevilla valle. Todo esto se realiz? partiendo del planteamiento de los objetivos, los cuales permitir?n lograr su cometido; en primer lugar, identificar a partir de los resultados qu? problem?ticas de comportamiento tienen los ni?os, en segundo lugar, implementar un plan de intervenci?n orientado a mejorar las relaciones interpersonales de los ni?os y en tercer lugar, evaluar el impacto generado con el plan de intervenci?n propuesto para tal fin. En cuanto al marco te?rico, se busc? el soporte en los postulados de diferentes autores, los cuales resultaron pertinentes para el abordaje conceptual de este, ya que hablan del desarrollo de la capacidad creadora, principios, normas y valores que hacen un clima escolar acorde para una educaci?n para la paz y una participaci?n democr?tica, como aspectos importantes a tener en cuenta en esta investigaci?n. Respecto a la metodolog?a, se desarroll? en base a la investigaci?n la investigaci?n acci?n-participativa y cooperativa, con un enfoque etnogr?fico, dentro del paradigma cualitativo. Tras esto, el resultado que se obtendr? del proceso estudiado, que junto a referentes te?ricos ayuda a explicar los procesos de la pr?ctica escolar estudiada.This research project process of building a culture of peace in preschool children through teaching strategies visible sensitizer is the scope in improving the skills of conflict resolution through recreational and artistic activities preschoolers educational institution Armando Romero Lozano the municipality of Seville valley. All this was done based on the approach of objectives, which will allow achieve its mission; first identified from the results which problematic behavior have children, secondly, implement an intervention plan aimed at improving interpersonal relationships of children and thirdly, to assess the impact generated with the intervention plan proposed for this purpose. As for the theoretical framework, support the propositions of different authors, which were relevant to the conceptual approach to this is sought, as they speak of the development of creativity, principles, norms and values that make a chord school climate for education for peace and democratic participation, as important aspects to consider in this research. Reading methodology was developed based on the research-participatory and cooperative action with an ethnographic approach, within the qualitative research paradigm. After this, the result you get the process under study, which together with theoretical framework helps explain the processes studied school practice Keywords: skills, peace, transition, norms, values and family

Generic two-phase coexistence in nonequilibrium systems

Gibbs' phase rule states that two-phase coexistence of a single-component system, characterized by an n-dimensional parameter-space, may occur in an n-1-dimensional region. For example, the two equilibrium phases of the Ising model coexist on a line in the temperature-magnetic-field phase diagram. Nonequilibrium systems may violate this rule and several models, where phase coexistence occurs over a finite (n-dimensional) region of the parameter space, have been reported. The first example of this behaviour was found in Toom's model [Toom,Geoff,GG], that exhibits generic bistability, i.e. two-phase coexistence over a finite region of its two-dimensional parameter space (see Section 1). In addition to its interest as a genuine nonequilibrium property, generic multistability, defined as a generalization of bistability, is both of practical and theoretical relevance. In particular, it has been used recently to argue that some complex structures appearing in nature could be truly stable rather than metastable (with important applications in theoretical biology), and as the theoretical basis for an error-correction method in computer science (see [GG,Gacs] for an illuminating and pedagogical discussion of these ideas).Comment: 7 pages, 6 figures, to appear in Eur. Phys. J. B, svjour.cls and svepj.clo neede