Formation of Common Investment Networks by Project Establishment between Agents

We present an investment model integrated with trust-reputation mechanisms where agents interact with each other to establish investment projects. We investigate the establishment of investment projects, the influence of the interaction between agents in the evolution of the distribution of wealth, as well as the formation of common investment networks and some of their properties. Simulation results show that the wealth distribution presents a power law in its tail. Also, it is shown that the trust and reputation mechanism presented leads to the establishment of networks among agents, which present some of the typical characteristics of real-life networks like a high clustering coefficient and short average path length

Phenomenological High Precision Neutron-Proton Delta-Shell Potential

We provide a successful fit for proton-neutron scattering below pion production threshold up to LAB energies of 350 MeV. We use seven high-quality fits based on potentials with different forms as a measure of the systematic uncertainty. We represent the interaction as a sum of delta-shells in configuration space below the 3fm and a charge dependent one pion exchange potential above 3fm together with magnetic and vacuum polarization effects. Special attention is paid to estimate the errors of the phenomenological interaction.Comment: 5 pages, 2 figures. Comments and one figure with differential observables adde

Higher codimension braneworlds from intersecting branes

We study the matching conditions of intersecting brane worlds in Lovelock gravity in arbitrary dimension. We show that intersecting various codimension 1 and/or codimension 2 branes one can find solutions that represent energy-momentum densities localized in the intersection, providing thus the first examples of infinitesimally thin higher codimension braneworlds that are free of singularities and where the backreaction of the brane in the background is fully taken into account.Comment: 20 pages; v2. references and comments added to match the published versio

Nontrival Cosmological Constant in Brane Worlds with Unorthodox Lagrangians

In self-tuning brane-world models with extra dimensions, large contributions to the cosmological constant are absorbed into the curvature of extra dimensions and consistent with flat 4d geometry. In models with conventional Lagrangians fine-tuning is needed nevertheless to ensure a finite effective Planck mass. Here, we consider a class of models with non conventional Lagrangian in which known problems can be avoided. Unfortunately these models are found to suffer from tachyonic instabilities. An attempt to cure these instabilities leads to the prediction of a positive cosmological constant, which in turn needs a fine-tuning to be consistent with observations.Comment: 17 pages, 1 figur

Resolving the Azimuthal Ambiguity in Vector Magnetogram Data with the Divergence-Free Condition: Application to Discrete Data

We investigate how the divergence-free property of magnetic fields can be exploited to resolve the azimuthal ambiguity present in solar vector magnetogram data, by using line-of-sight and horizontal heliographic derivative information as approximated from discrete measurements. Using synthetic data we test several methods that each make different assumptions about how the divergence-free property can be used to resolve the ambiguity. We find that the most robust algorithm involves the minimisation of the absolute value of the divergence summed over the entire field of view. Away from disk centre this method requires the sign and magnitude of the line-of-sight derivatives of all three components of the magnetic field vector.Comment: Solar Physics, in press, 20 pages, 11 figure

Incidencia de la podredumbre radical causada por "Phytophthora cinnamomi" en masas de "Quercus" en Andalucía

Entre los factores bióticos implicados en la Seca de los Quercus destaca la podredumbre radical causada por Phytophthora cinnamomi. En este trabajo se ha estudiado la incidencia de P. cinnamomi en masas de Quercus afectadas de Seca en Andalucía. El estudio se ha llevado a cabo en ocho fincas situadas en las cuatro provincias andaluzas más afectadas por este decaimiento forestal. En la mayor parte de las fincas P. cinnamomi ha sido el principal agente fitopatógeno asociado, aunque no el único. Se han observado diferencias morfológicas entre los aislados de P. cinnamomi obtenidos de encina y los procedentes de alcornoque, mientras que las temperaturas óptimas de crecimiento fueron similares para todos los aislados. Además, se ha estudiado la correlación entre la presencia del hongo en árboles afectados y las variables meteorológicas. Se ha establecido que el aislamiento de P. cinnamomi no presenta buena correlación con la lluvia acumulada, humedad del suelo o temperaturas registradas en las fincas antes de la toma de muestras, aunque le favorecieron las temperaturas mínimas y medias elevadas. The root rot caused by Phytophthora cinnamomi is one of the biotic factors frequently associated with Mediterranean oak decline. The aim of this work has been to study the incidence of P. cinnamomi in declining Quercus forests in southern Spain. It was carried out in eight forests located in the provinces most affected by oak decline. The fungus P. cinnamomi has been the main pathogen associated with decline symptoms, but other diseases and insect pests have also been detected. Morphological differences have been observed between the isolates of P. cinnamomi from Quercus ilex and those from Quercus suber. In contrast, optimal growth temperatures were similar for all the isolates. In addition, the presence of P. cinnamomi in infected trees has been correlated with some climatic variables. Fungal isolation did not result correlated with rain, soil humidity and temperature registered before sampling. However, isolation appeared as favoured by high minimum and average temperatures

Elevated atmospheric CO2 modifies responses to water-stress and flowering of Mediterranean desert truffle mycorrhizal shrubs

Predicted increases in atmospheric concentration of carbon dioxide (CO2) coupled with increased temperatures and drought are expected to strongly influence the development of most of the plant species in the world, especially in areas with high risk of desertification like the Mediterranean basin. Helianthemum almeriense is an ecologically important Mediterranean shrub with an added interest because it serves as the host for the Terfezia claveryi mycorrhizal fungus, which is a desert truffle with increasingly commercial interest. Although both plant and fungi are known to be well adapted to dry conditions, it is still uncertain how the increase in atmospheric CO2 will influence them. In this article we have addressed the physiological responses of H. almeriense × T. claveryi mycorrhizal plants to increases in atmospheric CO2 coupled with drought and high vapor pressure deficit. This work reports one of the few estimations of mesophyll conductance in a drought deciduous Mediterranean shrub and evaluates its role in photosynthesis limitation. High atmospheric CO2 concentrations help desert truffle mycorrhizal plants to cope with the adverse effects of progressive drought during Mediterranean springs by improving carbon net assimilation, intrinsic water use efficiency and dispersal of the species through increased flowering events

Inestabilidad lateral crónica de tobillo: hallazgos artroscópicos y resultados tras reparación mediante técnica de Karlsson

ObjetivoRecoger los resultados obtenidos asociando la artroscopia diagnóstico-terapéutica a la técnica propuesta por Karlsson.Material y métodoSe revisaron retrospectivamente 11 casos tratados entre diciembre de 2004 y julio de 2009 mediante cirugía artroscópica de tobillo asociada a la técnica de Karlsson. La media de edad fue de 25 años (rango 13-45). Primero se realizó la artroscopia y posteriormente el abordaje lateral para la reparación ligamentosa. El ligamento peroneo-calcáneo se reparó en los 4 casos en que se objetivó su lesión. Se valoró la funcionalidad según la escala de la American Orthopaedic Foot and Ankle Society (AOFAS) y el grado de satisfacción subjetiva. Se recogieron las complicaciones.ResultadosTras un seguimiento medio de 11 meses, valoramos 11 pacientes cuya puntuación media según la AOFAS fue de 84 puntos. La valoración subjetiva fue excelente en 7 casos, buena en 2 y mala en 2. Como complicaciones, hubo 2 casos de síndrome de dolor regional complejo (SDRC) y un paciente tuvo que ser reintervenido con técnica de Castaing II.ConclusionesConsideramos que la asociación de la artroscopia previa a la realización de la reconstrucción para el tratamiento de la inestabilidad crónica constituye una maniobra útil para el diagnóstico de patologías articulares asociadas, aportando información importante para el pronóstico funcional de la articulación.AimsThe purpose of this study is to evaluate the result of diagnostic and therapeutic arthroscopy in association with Karlsson technique.Material And MethodsBetween 2004 and 2009, 11 patients were operated by ankle arthroscopic surgery associated with Karlsson technique. The mean age was 25 years (range 13-45). Arthroscopy was performed first and secondly the lateral approach to ligament repair. Peroneal-calcaneal ligament wasn injuried and repaired in 4 cases. AOFAS scale was used for clinical and functional evaluation, and patients were asked about subjective satisfaction. Complications were recorded.ResultsAt a mean follow-up of 11 months the mean final score was 84 points on the AOFAS scale. The subjective assessment was excellent in 7 cases, good in 2 and poor in 2. There were 2 cases of CRPS and one patient was reoperated by Castaing II technique.ConclusionsWe believe that the association of arthroscopy prior to the reconstruction is useful for associated joint lesion diagnosis, providing important information for the functional prognosis of the joint

A Low-Cost IoT-Based System to Monitor the Location of a Whole Herd

Animal location technologies have evolved considerably in the last 60 years. Nowadays, animal tracking solutions based on global positioning systems (GPS) are commercially available. However, existing devices have several constraints, mostly related to wireless data transmission and financial cost, which make impractical the monitorization of all the animals in a herd. The main objective of this work is to develop a low-cost solution to enable the monitorization of a whole herd. An IoT-based system, which requires some animals of the herd being fitted with GPS collars connected to a Sigfox network and the rest with low-cost Bluetooth tags, has been developed. Its performance has been tested in two commercial farms, raising sheep and beef cattle, through the monitorization of 50 females in each case. Several collar/tag ratios, which define the cost per animal of the solution, have been simulated. Results demonstrate that a low collar/tag ratio enable the monitorization of a whole sheep herd. A larger ratio is needed for beef cows because of their grazing behavior. Nevertheless, the optimal ratio depends on the purpose of location data. Large variability has been observed for the number of hourly and daily messages from collars and tags. The system effectiveness for the monitorization of all the animals in a herd has been certainly proved

Scalar brane backgrounds in higher order curvature gravity

We investigate maximally symmetric brane world solutions with a scalar field. Five-dimensional bulk gravity is described by a general lagrangian which yields field equations containing no higher than second order derivatives. This includes the Gauss-Bonnet combination for the graviton. Stability and gravitational properties of such solutions are considered, and we particularily emphasise the modifications induced by the higher order terms. In particular it is shown that higher curvature corrections to Einstein theory can give rise to instabilities in brane world solutions. A method for analytically obtaining the general solution for such actions is outlined. Genericaly, the requirement of a finite volume element together with the absence of a naked singularity in the bulk imposes fine-tuning of the brane tension. A model with a moduli scalar field is analysed in detail and we address questions of instability and non-singular self-tuning solutions. In particular, we discuss a case with a normalisable zero mode but infinite volume element.Comment: published versio