Pattern formation in a predator-prey system characterized by a spatial scale of interaction

We describe pattern formation in ecological systems using a version of the classical Lotka-Volterra model characterized by a spatial scale which controls the predator-prey interaction range. Analytical and simulational results show that patterns can emerge in some regions of the parameters space where the instability is driven by the range of the interaction. The individual-based implementation captures realistic ecological features. In fact, spatial structures emerge in an erratic oscillatory regime which can contemplate predators' extinction.Comment: 5 pages, 4 figure

Filogenia molecular y estimación del tiempo de divergencia en pennatuláceos (Cnidaria: Octocorallia: Pennatulacea)

Pennatulaceans are an important component of benthic marine communities usually related to soft bottoms. Despite their important ecological role, as yet little is known about their origin and divergence time. The first attempts to establish phylogenetic relationships among genera date from the early 20th century, when only morphological characters were available. In the last decade, phylogenetic analyses based on mitochondrial DNA sequences from a selected number of species have proposed a different hypothetical ancestor for this group, but their intergeneric relationships remain obscure. The present study is based on a combination of mitochondrial and nuclear markers (mtMutS, Cox1 and 28S rDNA), adding new molecular information about the phylogenetic relationships among the pennatulacean genera, including 38 new sequences belonging to 13 different species. Some of the phylogenetic relationships inferred in the present study question the current classification of sea pens based on morphology (at different taxonomic levels), clearly indicating that the two main groups Sessiliflorae and Subselliflorae, some of their main families (e.g. Pennatulidae, Umbellulidae, Virgulariidae) and some genera (e.g. Umbellula, Veretillum) are non-monophyletic. In addition, the veretillids, traditionally considered the most primitive pennatulaceans, are not shown as the earliest-diverging taxon. Moreover, an analysis of divergence time performed here suggested that the origin of the pennatulaceans dates from the Lower Cretaceous (Berriasian, ~144 Ma), in agreement with their sparsely known fossil record, while the initial divergence of most extant genera occurred in the Oligocene and Miocene times.Los pennatuláceos son un componente importante de las comunidades bentónicas marinas generalmente relacionados con fondos blandos. A pesar de su importante papel ecológico, la información sobre su origen y tiempo de divergencia es aún escasa. Los primeros intentos de establecer relaciones filogenéticas entre géneros datan de principios del siglo XX, cuando sólo estaban disponibles caracteres morfológicos. En la última década, los análisis filogenéticos basados en secuencias de ADN mitocondrial procedentes de un limitado número de especies han propuesto un ancestro hipotético diferente para este grupo, pero sus relaciones intergenéricas permanecen oscuras. La presente investigación está basada en una combinación de marcadores mitocondriales y nuclear (mtMutS, Cox1 y ADNr 28S), aportando nueva información molecular sobre las relaciones filogenéticas entre los géneros de pennatuláceos, incluyendo 38 nuevas secuencias pertenecientes a 13 especies. Algunas de las relaciones filogenéticas inferidas en el presente estudio cuestionan la actual clasificación de las plumas de mar basada en la morfología (a diferentes niveles taxonómicos), indicando claramente que los dos grupos principales Sessiliflorae y Subselliflorae, algunas de sus principales familias (por ejemplo Pennatulidae, Umbellulidae, Virgulariidae) y algunos géneros (por ejemplo Umbellula, Veretillum) son no-monofiléticos. Asimismo, los veretílidos, tradicionalmente considerados los pennatuláceos más primitivos, no se muestran como el taxón divergente más antiguo. Además, un análisis del tiempo de divergencia realizado en este trabajo sugirió que el origen de los pennatuláceos data del Cretácico Inferior (Berriasiano, ~ 144 Ma), de acuerdo con su escasamente conocido registro fósil, mientras que la divergencia inicial de la mayoría de los géneros existentes ocurrió en tiempos del Oligoceno y Mioceno

Tratamiento quirúrgico de las roturas del tendón de Aquiles

El objetivo del trabajo fue valorar los resultados y complicaciones obtenidos tras tratamiento quirúrgico de las rupturas subcutáneas del tendón de Aquiles. Se revisaron 26 pacientes, con un seguimiento mínimo de 1 año. Detallamos nuestra metodología en cuanto a técnica quirúrgica y manejo postoperatorio. Se valoró el resultado clínico según los siguientes parámetros: movilidad de tobillo, potencia muscular tríceps, engrosamiento tendinoso, claudicación a la marcha, atrofia gemelar, incorporación a actividades deportivas y alteraciones residuales. Los resultados fueron muy buenos en 21 casos (80,7%); buenos en 5 (19,3%), y ningún caso con resultado regular o malo. Destacamos 5 complicaciones postoperatorias inmediatas y 1 caso de reruptura, con resultado final satisfactorio. Dados los buenos resultados obtenidos, recomendamos el tratamiento quirúrgico en pacientes activos, con buen estado general, independientemente de la edad.The objective of this work was to asess the clinical results and complications with the surgical treatment for subcutaneous Achilles tendon ruptures. Twenty six patients were clinically revised with a minimal follow up of one year. We detailed the surgical technique and postoperative management of the patients. Clinical results were assessed with the next parameters: ankle joint motion; triceps muscle strength; Achilles tendinous thickened; walking limp; triceps muscle atrophy, possibility of sports practice and definitive changes. We had excellent results in 21 cases (80,7%); good results in 5 cases (19,3%) and none with fair or poor results. We detached 5 cases with immediate postoperative complications and one case of relapse, all of them with good clinical result. Our excellent and good clinical results with the surgical technique for the Achilles tendon ruptures allow us to recommend this treatment in active patients, with appropriate health conditions in spite of the age

A novel growth method to improve the quality of GaAs nanowires grown by Ga-assisted chemical beam epitaxy

The successful synthesis of high crystalline quality and high aspect ratio GaAs nanowires (NWs) with a uniform diameter is needed to develop advanced applications beyond the limits established by thin film and bulk material properties. Vertically aligned GaAs NWs have been extensively grown by Ga-assisted vapor–liquid–solid (VLS) mechanism on Si(111) substrates, and they have been used as building blocks in photovoltaics, optoelectronics, electronics, and so forth. However, the nucleation of parasitic species such as traces and nanocrystals on the Si substrate surface during the NW growth could affect significantly the controlled nucleation of those NWs, and therefore the resulting performance of NW-based devices. Preventing the nucleation of parasitic species on the Si substrate is a matter of interest, because they could act as traps for gaseous precursors and/or chemical elements during VLS growth, drastically reducing the maximum length of grown NWs, affecting their morphology and structure, and reducing the NW density along the Si substrate surface. This work presents a novel and easy to develop growth method (i.e., without using advanced nanolithography techniques) to prevent the nucleation of parasitic species, while preserving the quality of GaAs NWs even for long duration growths. GaAs NWs are grown by Ga-assisted chemical beam epitaxy on oxidized Si(111) substrates using triethylgallium and tertiarybutylarsine precursors by a two-step-based growth method presented here; this method includes a growth interruption for an oxidation on air between both steps of growth, reducing the nucleation of parasitic crystals on the thicker SiOx capping layer during the second and longer growth step. VLS conditions are preserved overtime, resulting in a stable NW growth rate of around 6 μm/h for growth times up to 1 h. Resulting GaAs NWs have a high aspect ratio of 85 and average radius of 35 nm. We also report on the existence of characteristic reflection high-energy electron diffraction patterns associated with the epitaxial growth of GaAs NWs on Si(111) substrates, which have been analyzed and compared to the morphological characterization of GaAs NWs grown for different times under different conditions

A survey of the genera Sarcodictyon Forbes, 1847, and rolandia Lacaze-Duthiers, 1900, (anthozoa: octocorallia) in the North-eastern Atlantic and the Mediterranean

Sarcodictyon catenatum Forbes, 1847, is a common species in the Atlantic and the Mediterranean. However, often it has been mistaken for Rolandia coralloides Lacaze-Duthiers, 1900. On the basis of British and Mediterranean material we studied the main characters for distinguishing S. catenatum. We consider Rolandia coralloides Lacaze-Duthiers, 1900, to be a valid species and we assign to it all the material named Rolandia rosea by S. Weinberg (1978). Furthermore, a histological study confirmed that R. coralloides typically forms groups of polyps embedded in a common coenenchyme. Therefore, the possibility of transferring R. coralloides from Stolonifera to Alcyonacea is discussed. Evagorgia rosea Philippi, 1842, is here considered to be a nomen dubium

Psychometric properties and factor structure of the brief Wisconsin Inventory of Smoking Dependence Motives among Spanish smokers from the general population

Introduction: The brief version of the Wisconsin Inventory of Smoking Dependence Motives (B-WISDM) is a well-established instrument to measure the multidimensional nature of nicotine dependence. However, no previous research has assessed its psychometric properties in the Spanish context. The aim of the present study was to analyze the factor structure and measurement invariance across gender of this instrument among Spanish smokers from the general population. Methods: This cross-sectional study assessed 480 smokers through an online questionnaire including information on tobacco use and several nicotine dependence measures. Confirmatory Factor Analysis was used to assess the factorial structure of the Spanish B-WISDM, its internal consistency, measurement invariance across gender and convergent validity with the Fagerstr¨om Test for Nicotine Dependence (FTND) and the Glover-Nilsson Smoking Behavioral Questionnaire (GN-SBQ) scores. Results: Results indicate that the eleven correlated factors solution had a better fit when compared to the other tested models (two correlated factors and two second-order factors with eleven first-order correlated factors solution), remaining such structure invariant across gender. Internal consistency of the scale was high (α =0.950; dimension α values ranged between 0.657 and 0.921). Overall scores and dimensions of the scale significantly and positively correlated with other nicotine dependence measures (except for Social/Environmental Goads and FTND). Conclusions: This is the first version of the B-WISDM validated to assess nicotine dependence with a multidimensional perspective within the Spanish culture. Results show adequate psychometric properties regarding its factor structure and measurement invariance across gender, supporting its utility to evaluate the motives driving tobacco use among Spanish smokers from the general population

Gestión para el cambio de la cultura docente a partir del proceso de la planeación didáctica

El presente trabajo es una propuesta de gestión que busca favorecer el cambio de cultura en la función docente, específicamente en relación a la planeación didáctica. El proyecto se orientó a fortalecer el desempeño docente a través de un proceso personal y colaborativo de trabajo colegiado entre los miembros del equipo docente de la institución donde se elaboró. La metodología empleada fue la de intervención educativa, la cual nos permitió reconocer al sujeto en relación con el contexto y la dinámica de la interacción social, de tal modo que desde la perspectiva de la gestión, responda a las necesidades específicas del centro educativo

Rotura traumática del tendón del supraespinoso en un niño de seis años

Presentamos un caso de un niño de seis años que sufrió un traumatismo por caída sobre su hombro derecho, con rotura completa del tendón del supraespinoso. Comprobado con Resonancia Magnética. Se operó para efectuar una reinserción transósea del tendón mediante cirugía abierta. Después de un mes de inmovilización se comenzaron los ejercicios activos progresivos con recuperación completa a los tres meses de la intervención.A six year old boy sustained a right shoulder injury after a causal fall. Magnetic Resonance Imaging showed a complete rupture of the supraespinatus tendon. Open surgery was indicated by transosseus reinsertion of the tendon on the humeral head. After one month of shoulder immobilization, the patient physical therapy with progressive active exercises. The patient achivied complete joint motion and function three months after surgery

Tratamiento quirúrgico de la fractura de acetábulo con luxación posterior de cadera: análisis retrospectivo de 20 casos

Entre 1985 y 1990 fueron intervenidos en nuestro servicio 20 pacientes con fractura acetabular y luxación posterior de cadera, con edades desde 22 a 53 años, 18 (90%) eran varones. Los accidentes de tráfico fueron la causa de 18 (90%) de las lesiones. Diez (50%) presentaron lesiones asociadas de importancia. Se estudió su evolución con un seguimiento medio de 5 años (rango de 3.5 a 8.1). La fractura de pared posterior ha sido la que con mayor frecuencia se ha asociado a la luxación (50%), seguida de la transversa y de pared posterior (30%). Hemos obtenido 14 (70%) resultados satisfactorios; 2 pacientes precisaron artroplastia total a los 3 años. No se observó peor evolución en los casos de mayor edad, pero sí en aquéllos que fueron intervenidos pasadas las 3 semanas del accidente. Se comentan aspectos de la evaluación preoperatoria.Between 1985 and 1990, 20 patients aged from 22 to 53 years with fracture of the acetabulum and posterior dislocation of the femoral head were treated surgically. Eighteen (90%) were male. Eighteen (90%) of the fractures were sustained in a motor-vehicle accident. Ten (50%) patients had multiple associated injuries. The average duration of the follow-up period was 5 years (range from 3.5 to 8.1). Ten (50%) of the dislocations were associated with posterior wall fracture. We observed 14 (70%) satisfactory results; 2 patients needed a THA 3 years later. Best results were achieved with early treatment. Aspects of the preoperative evaluation are commented