Homoclinic organization in the Hindmarsh-Rose model: A three parameter study

Bursting phenomena are found in a wide variety of fast-slow systems. In this article, we consider the Hindmarsh-Rose neuron model, where, as it is known in the literature, there are homoclinic bifurcations involved in the bursting dynamics. However, the global homoclinic structure is far from being fully understood. Working in a three-parameter space, the results of our numerical analysis show a complex atlas of bifurcations, which extends from the singular limit to regions where a fast-slow perspective no longer applies. Based on this information, we propose a global theoretical description. Surfaces of codimension-one homoclinic bifurcations are exponentially close to each other in the fast-slow regime. Remarkably, explained by the specific properties of these surfaces, we show how the Hindmarsh-Rose model exhibits isolas of homoclinic bifurcations when appropriate two-dimensional slices are considered in the three-parameter space. On the other hand, these homoclinic bifurcation surfaces contain curves corresponding to parameter values where additional degeneracies are exhibited. These codimension-two bifurcation curves organize the bifurcations associated with the spike-adding process and they behave like the "spines-of-a-book, " gathering "pages" of bifurcations of periodic orbits. Depending on how the parameter space is explored, homoclinic phenomena may be absent or far away, but their organizing role in the bursting dynamics is beyond doubt, since the involved bifurcations are generated in them. This is shown in the global analysis and in the proposed theoretical scheme

Kin discrimination in cannibalistic tadpoles of the Green Poison Frog, Dendrobates auratus (Anura, Dendrobatidae)

O consumo de indivíduos aparentados pode reduzir a aptidão inclusiva do canibal. Assim, mecanismos que permitam que um girino reconheça seus relativos e modifique seu comportamento pode reduzir os custos do canibalismo. Alternativamente, fatores ecológicos podem tornar o tratamento preferencial dos relativos custoso demais para que seja favorecido pela seleção natural. Testamos essas duas previsões no dendrobatídeo Dendrobates auratus. O efeito do parentesco sobre o canibalismo larval foi examinado por meio de uma série de tentativas de discriminação de parentes. Observamos o comportamento de girinos de grande porte diante de dois girinos menores imobilizados, um irmão e outro não-aparentado. Nesses testes de apresentação simultânea, os girinos mostraram uma preferência significativa por atacar irmãos. Em outra série de tentativas, pares de girinos de tamanhos diferentes foram colocados juntos em aquários. A maioria dos girinos de grande porte (70%) consumiu o girino menor em menos de 24 horas. O parentesco não afetou o tempo de sobrevivência do girino pequeno. Nossos resultados são consistentes com as observações de que D. auratus é um predador indiscriminado. Como os co-específicos podem ser fortes competidores, sua eliminação rápida poderia ser vantajosa, particularmente nas pequenas poças pobres em nutrientes utilizadas por essa espécie.Cannibalizing a related individual can reduce the inclusive fitness of the cannibal. Hence, mechanisms that allow a tadpole to recognize and modify its behavior toward kin may reduce the inclusive fitness costs of cannibalism. Alternatively, ecological factors may cause preferential treatment of kin to be too costly to be favored by selection. We tested these two predictions in the Green Poison Frog, Dendrobates auratus. The effect of kinship on larval cannibalism was examined through a series of kin-discrimination trials. The behavior of large tadpoles was observed when presented with two small, tethered tadpoles, one a clutchmate and one an unrelated tadpole. In these simultaneous presentation tests, tadpoles displayed a significant preference for attacking kin. In a series of timed trials, pairs of unequally sized tadpoles were placed together in containers. The majority (70%) of large tadpoles took less than 24 hr to consume the small tadpole. Kinship did not affect the survival time of the small tadpole. Our results are consistent with observations that D. auratus is an indiscriminate predator. As conspecifics may be serious competitors, their swift elimination would be an advantage, particularly in the small, nutrient-poor pools used by this species

Instalación eléctrica para fábrica de conservas vegetales

En este proyecto fin de carrera se va a describir la instalación eléctrica en baja tensión de una nave industrial dedicada a la elaboración de conservas vegetales. La instalación eléctrica constará de: - Instalación de alumbrado general y de emergencia; - Instalación de fuerza y tomas de corriente; - Centro de transformación propio de media a baja tensión; - Protección eléctrica de las líneas que alimentan todas las instalaciones; - Puestas a tierra del centro de transformación, y de la instalación eléctrica de la nave; - Corrección del factor de potencia con batería de condensadores de la instalación eléctrica de la nave.Ingeniería Técnica IndustrialIndustria Ingeniaritza Tekniko

Implementación de juegos usando algoritmos evolutivos

El objetivo de este proyecto, ha sido implementar juegos convencionales aplicando las técnicas de los algoritmos evolutivos. Los algoritmos evolutivos son un grupo de algoritmos de búsqueda basados en la evolución y selección natural de las especies en el mundo real. Estas técnicas incluyen algoritmos genéticos, los cuales trabajan con estructuras binarias para representar a los individuos de una población. Los juegos son una parte muy interesante dentro del campo de la programación evolutiva, ya que en ellos se pueden aplicar muchas de las características típicas de los algoritmos evolutivos. En este proyecto hemos implementado un gran número de juegos como el mastermind, puzzles… y otros juegos donde el contrincante ha sido el ordenador. Para cada juego hemos elegido la representación de los individuos y la funciónde aptitud más apropiadas para conseguir juegos que devolvieran soluciones óptimas, finalidad primera de los algoritmos evolutivos. [ABSTRACT] The objective of this project, has been to implement conventional games applying the techniques of the evolutionary algorithms.. The evolutionary algorithms are a group of algorithms search based on the evolution and natural selection of the species in the real world. These techniques include genetic algorithms, which work with binary structures to represent the individuals of a population. The games are a very interesting part within the field of the evolutionary programming, since in them many of the typical characteristics of the evolutionary algorithms can be applied. In this project we have implemented a great number of games like mastermind, puzzles, labyrinths... and other games where the opponent has been the computer. For each game we have chosen the representation of the individuals and the more appropriate function of aptitude to obtain games that gave back optimal solutions, purpose first of the evolutionary algorithms

A neural networks approach to aerofoil noise prediction

A neural network noise prediction model for a turbulent boundary layer noise mechanism has been created using a feed forward multilayer perceptron and a noise spectrum database collected from a family of NACA 0012 areofoils. The results of the neural network model were compared against the Brooks model and it was found that the quality of the prediction was improved was improved over the entire range of the data. The model was also validated against experimental data not utilized the training of the neural, with positive results.Preprin

A striking new species of Anolis lizard (Squamata, Iguania) from Panama

Aquí describimos una especie nueva de lagartija Anolis de Panamá. Esta forma nueva es más similar a Anolis mirus y A. parilis de América del Sur, pero difiere en caracteres del patrón de color y de escamas. La especie nueva parece ser un pariente cercano de otras Anolis Alfa grandes de tierra firme (grupo latifrons; Dactyloa).Here we describe a new Anolis lizard from Panama. The new form is most similar to South American Anolis mirus and Anolis parilis but differs in characters of color pattern and scalation. The new species appears to be a close relative of other large mainland Alpha Anolis (latifrons group; "Dactyloa")

Hematology, Biochemistry and Serum Protein Analyses of Antarctic and non-Antarctic Skuas

Determination of hematological and biochemical parameters provides important data to assess the physiological condition in wild birds. Therefore, to carry out ecophysiology or conservation studies it is essential to establish baseline physiological parameters and how these change with age and life history events. Hematological (hematocrit, hemoglobin and erythrocyte sedimentation) and biochemical (glucose, total lipids and proteins, aspartate and alanine aminotransferase activities and electrolyte concentration) reference values were determined in two Antarctic migratory bird species, the Brown Skua (Stercorarius antarcticus) and South Polar Skua (S. maccormicki), from South Shetland Island during breeding season. Also, hematological data (hematocrit) were determined for non-Antarctic skuas, with Chilean (S. chilensis) and Falkland (S. antarcticus antarcticus) skuas sampled in the Beagle Channel islands (Tierra del Fuego Province) and Viana Island (Chubut Province), Argentina, respectively. Differences between adult Antarctic skua species were observed in hemoglobin, erythrocyte sedimentation, total lipids and aspartate aminotransferase activity. In addition, age-related differences in Antarctic skuas in hematocrit, hemoglobin, glucose and total protein values were observed. Serum reference protein fractions (Albumin, α1, α2, and globulins) were assessed by electrophoresis for Antarctic and non-Antarctic skuas. Similar protein patterns were observed between South Polar and Chilean skuas as well between Falkland Skua and Brown Skua. The differences between adult sympatric Antarctic skuas may be related to their nutritional status and species-specific migrations, feeding habits and the differential use of the breeding niches, while the age variation may be related to physiological development processes in chicks or to the energy expenditure in adults during breeding.Facultad de Ciencias Naturales y Muse

Determination of thermal conductivity variation through Modified Transient Plane Source (MTPS), and its relationship with porosity variation on thermally treated Prada limestone

In this research, the variation of thermal conductivity with temperature of a limestone and its relationship with porosity is studied. Samples from Prada formation, a lower Cretaceous limestone from the Catalan Pyrenees (Spain), obtained from the Tres Ponts road tunnel were subjected to temperatures of 105, 300, and 600 °C and then cooled at a slow rate by air-cooling to laboratory temperature. Open porosity tests were determined before and after heating to evaluate the porosity increase and the micro-cracks growth. Complementarity, thermal conductivity was measured in the rock samples before and after the application of a thermal treatment by means of C-Therm TCi device, a Modified Transient Plane Source (MTPS). This is a non-invasive, quick, and precise method, when compared with other steady-state laboratory alternatives, widely used to directly determine thermal properties of rock samples. A clear decrease in the thermal conductivity of above 10% was observed for samples heated at 600 °C, probably due to a dramatic increase in porosity. The obtained results could be of great interest for the incorporation of the effect of temperature on rock in numerical models, to evaluate the potential impacts induced by eventual fires developed inside the Tres Ponts tunnel.This work was supported by the Department of Geological and Geotechnical Engineering, Universitat Politècnica de València

A numerical investigation of wind tunnel model deformations caused by the twin-sting support system

This work presents a wing deformation analysis of a twin-sting-mounted commercial aircraft model. Twin-sting arrangements minimize flow disturbances around the model fuselage and tail; on the other hand, they cause important changes in the flow field around the wing and also increase aerodynamic interference at the wing and aeroplastic effects on the wing. In some cases, these effects can alter the normal downwash developed behind the wing, modifying the flow pattern at the tail. Consequently, when tail aerodynamics is a major concern, this kind of support interference should be carefully evaluated. The methodology developed in this work employs an unstructured FEM-based flow solver for computing aerodynamic loads. These loads are then transferred to a finite element structural model in order to assess the geometrical deformation of the wing caused by the torsional moment exerted by the supporting mechanism. The analysis described involves there different twin-sting support configurations taking into account angle of attack variations and Mach numbers spanning from subsonic to high transonic ranges.Preprin