376 research outputs found
Sobre la biología del águila calzada Hieraëtus pennatus (Gmelin, 1788) en Navarra
Trata el presente trabajo de aspectos de la Biología del Águila calzada (Hieraétus
pennatus) durante el período reproductor según observaciones realizadas en unos parajes de
la zona media de Navarra.
Comienza con la descripción del sistema de trabajo y posteriormente, se describe la
especie, su habitat, distribución geográfica y estatus en Navarra.
Según fechas de observación de los autores se trata de la fenología de migración. Un
capítulo más extenso describe el comportamiento territorial y nupcial de la especie y se
dan todos los datos básicos relativos a fechas de puesta de huevos, nacimiento de los
pollos, período de dependencia con sus padres etc. Se citan observaciones originales
relativas a la agresividad entre los pollos en varias especies de rapaces. Se dan datos
sobre alimentación de las especies y el trabajo acaba describiendo los cambios de los
individuos que compusieron una pareja de águilas calzadas que nidificó en el mismo bosque
durante 17 años, pudiéndose estudiar, por ello, la productividad de tal pareja en dicho
período de tiempo
Lineal perspective estimation on monocular images
Depth estimation from monocular images can be retrieved from the perspective distortion. One major e ect of this distortion is that a set of parallel lines in the real world converges into a single point in the image plane. The estimation of the coordinates of the vanishing point can be retrieved directly by di erent ways, like Hough Transform and First derivative approaches. Many of them work on speci c real scene characteristics and often lead to spurious vanishing points.
Technology and computational advances suggest that some re nements to these simple techniques or a combination of them could lead to more con dent vanishing point detection than modelling and developing a new complicated ones.
In this paper we study the behaviour of two classical approaches, introduce them some improvements and propose a new combinational technique to estimate the location of the vanishing point in an image. The solutions will be described and compared, also through the discussion of the results obtained from their application to real images.Presentado en el VIII Workshop Computación Gráfica, Imágenes y Visualización (WCGIV)Red de Universidades con Carreras en Informática (RedUNCI
Modeling flocks with perceptual agents from a dynamicist perspective
Computational simulations of flocks and crowds have typically been processed by a set of logic or syntactic rules. In recent decades, a new generation of systems has emerged from dynamicist approaches in which the agents and the environment are treated as a pair of dynamical systems coupled informationally and mechanically. Their spontaneous interactions allow them to achieve the desired behavior. The main proposition assumes that the agent does not need a full model or to make inferences before taking actions; rather, the information necessary for any action can be derived from the environment with simple computations and very little internal state. In this paper, we present a simulation framework in which the agents are endowed with a sensing device, an oscillator network as controller and actuators to interact with the environment. The perception device is designed as an optic array emulating the principles of the animal retina, which assimilates stimuli resembling optic flow to be captured from the environment. The controller modulates informational variables to action variables in a sensory-motor flow. Our approach is based on the Kuramoto model that describes mathematically a network of coupled phase oscillators and the use of evolutionary algorithms, which is proved to be capable of synthesizing minimal synchronization strategies based on the dynamical coupling between agents and environment. We carry out a comparative analysis with classical implementations taking into account several criteria. It is concluded that we should consider replacing the metaphor of symbolic information processing by that of sensory-motor coordination in problems of multi-agent organizations
Estudio ornitológico de los parques y alrededores de Pamplona
Se ha estudiado la ornitofauna de 5 parques de Pamplona y 4
áreas de su periferia. Respecto al estudio cualitativo, se ha
realizado una clasificación fenológica de las aves observadas,
habiéndose catalogado 110 especies. En relación al estudio
cuantitativo, se ha procedido a la comparación de las distintas
áreas muestreadas mediante métodos estadísticos, habiéndose
encontrado gran similitud entre los parques de mayor extensión
incluidos en el casco de la ciudad. De igual modo se encuentra una
más estrecha relación entre las áreas ribereñas del río
Arga, que la existente entre otras zonas de la periferia
Lineal perspective estimation on monocular images
Depth estimation from monocular images can be retrieved from the perspective distortion. One major e ect of this distortion is that a set of parallel lines in the real world converges into a single point in the image plane. The estimation of the coordinates of the vanishing point can be retrieved directly by di erent ways, like Hough Transform and First derivative approaches. Many of them work on speci c real scene characteristics and often lead to spurious vanishing points.
Technology and computational advances suggest that some re nements to these simple techniques or a combination of them could lead to more con dent vanishing point detection than modelling and developing a new complicated ones.
In this paper we study the behaviour of two classical approaches, introduce them some improvements and propose a new combinational technique to estimate the location of the vanishing point in an image. The solutions will be described and compared, also through the discussion of the results obtained from their application to real images.Presentado en el VIII Workshop Computación Gráfica, Imágenes y Visualización (WCGIV)Red de Universidades con Carreras en Informática (RedUNCI
8-PropargylaminoBODIPY: unprecedented blue-emitting pyrromethene dye. Synthesis, photophysics and laser properties
Highly emitting 8-propargylaminoBODIPY (8-PAB) 2 was
prepared in 94% yield. Unlike any other BODIPY structure
hitherto described in the literature, 2 displays efficient emission in
the blue region of the visible spectrum with a fluorescence
quantum yield up to 0.94 and high laser efficiency (35%) at
483 nm.Grants GTO-2007-C02-69094 (CONCyTEG) (Mexico),
MAT2007-65778-C02-01 and -02 of the Spanish MICINN
are gratefully acknowledged. V. Martin thanks CSIC for her
JAE-postdoctoral contract.Peer reviewe
Bichromatic laser emission from dipyrromethene dyes incorporated into solid polymeric media
9 pages, 9 figures.Bichromatic laser emission from dipyrromethene-based solid-state dye lasers is reported. The dependence of this dual emission on different factors and its origin and causes are discussed in the light of different models proposed in the literature. Our experimental results indicate that the long-wavelength emission can be explained in terms of reabsorption/reemission effects and inhomogeneous broadening of the S0-S1 transition. The short-wavelength emission corresponds to the usual S0-S1 transition and dominates at low dye concentration.This work was supported by Project Nos. MAT2004-04643-C03-01 and MAT2004-04643-C03-02 of the Spanish CICYT. One of the authors (M.Á.) thanks Ministerio de Ciencia y Tecnología (MCT) for a predoctoral grant. Another author (M.L.) thanks Comunidad Autónoma de Madrid for a postdoctoral grant and MCT for a Juan de la Cierva contract.Peer reviewe
Reconstrucción del ligamento cruzado anterior en pacientes mayores de 40 años
Aim. Assess the results of the reconstruction of the anterior cruciate ligament (ACL) in patients over 40 years after a minimum follow-up of 24 months. Material and Methods. Retrospective review of 37 patients undergoing surgery for ACL reconstruction between 2002-2013, over 40 years with a minimum follow-up of 24 months. 25 patients were available for clinical review, which consisted of physical examination, radiographic and arthrometric KT-1000 studies, functional tests and subjective assessment of the knee through surveys (International Knee Documentation Committee (IKDC), Tegner and Lysholm-Tegner). Results. At follow-up, at least 2 of the 3 knee instability maneuvers (Pivot-shift, Lachman, Anterior drawer test) were positive in 6 of 25 patients (24%). The difference of antero-posterior laxity compared with the healthy knee using KT-1000 arthrometer to 89N was greater than 3mm in 5 patients (20%). None had a greater difference of 5mm. Only 6 patients recovered their previous level of activity, according to the Tegner test. However, the average score on the Lysholm test was 81,40 ± 19,56 points, with good or excellent results in 15 patients (60%). IKDC test results were less conspicuous, with good or excellent results in 7 patients (28%). Conclusions. The results after ACL reconstruction in patients older than 40 years old are good, with a high degree of satisfaction and are comparable to those in younger patients. Although return to previous activity level is less than in younger groups, age should not be a limiting to indicate an ACL reconstruction factor in an unstable knee
Rotura no traumática de componente cerámica-cerámica en PTC: presentación de un caso y revisión de la literatura.
Las fracturas de los componentes cerámicos empleados en artroplastia total de cadera (ATC) son
infrecuentes. El objetivo de nuestro trabajo es presentar un caso de rotura precoz no traumática de componente ce
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rámica-cerámica en ATC y revisar la literatura en relación con esta complicación. Se trata de un paciente de 58
años diagnosticado de necrosis avascular de cabeza femoral, fue intervenido mediante ATC, implantándosele un par
cerámica-cerámica. A los 4 meses de la intervención, sin antecedente traumático previo, se observó fractura de la
cúpula de cerámica de la prótesis. El paciente precisó de recambio protésico, utilizándose el par cerámica-polietileno.
La fractura de los componentes del par cerámica- cerámica es poco frecuente. El fallo puede ser debido a un defecto
de fabricación o en la colocación del implante. Los pacientes deben ser informados sobre la posibilidad de sufrir esta
complicación antes de la implantación de una PTC con par cerámica-cerámica.Fractures of ceramic components used in total hip replacement (THR) are uncommon. To report
a case of early non-traumatic rupture ceramic-ceramic component in THR and review the literature regarding this
complication. A 58 years diagnosed with avascular necrosis of the femoral head, was operated by THR, a ceramic-on
-ceramic. At 4 months after surgery, without previous trauma, fracture was observed ceramic dome of the prosthesis.
The patient required replacement, using the ceramic-on-polyethylene. The fracture of ceramic components is rare.
The failure may be due to a manufacturing defect or implant placement. Patients should be informed about the possi
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bility of having this complication before implantation of a THR ceramic-on-ceramic
The mechanisms used by enteropathogenic Escherichia coli to control filopodia dynamics
Enteropathogenic Escherichia coli (EPEC) subverts actin dynamics in eukaryotic cells by injecting effector proteins via a type III secretion system. First, WxxxE effector Map triggers transient formation of filopodia. Then, following recovery from the filopodial signals, EPEC triggers robust actin polymerization via a signalling complex comprising Tir and the adaptor proteins Nck. In this paper we show that Map triggers filopodia formation by activating Cdc42; expression of dominant-negative Cdc42 or knock-down of Cdc42 by siRNA impaired filopodia formation. In addition, Map binds PDZ1 of NHERF1. We show that Map–NHERF1 interaction is needed for filopodia stabilization in a process involving ezrin and the RhoA/ROCK cascade; expression of dominant-negative ezrin and RhoA or siRNA knock-down of RhoA lead to rapid elimination of filopodia. Moreover, we show that formation of the Tir-Nck signalling complex leads to filopodia withdrawal. Recovery from the filopodial signals requires phosphorylation of a Tir tyrosine (Y474) residue and actin polymerization pathway as both infection of cells with EPEC expressing TirY474S or infection of Nck knockout cells with wild-type EPEC resulted in persistence of filopodia. These results show that EPEC effectors modulate actin dynamics by temporal subverting the Rho GTPases and other actin polymerization pathways for the benefit of the adherent pathogen
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