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In birds, the magnitude of the adrenocortical stress response can be down‐regulated during specific life‐history stages. Such modulation likely occurs when the effects of mounting robust corticosterone (Cort) elevations interfere with the normal progression of critical lifecycle activities (e.g. development, molt, migration, reproduction). The Developmental Hypothesis posits that altricial birds should display a “Stress Hyporesponsive Period” during the early post‐natal life stages, characterized by reduced adrenocortical stress responses compared to adult birds and a gradual age‐related increase. Such modulation would allow avoiding the potential deleterious effects that long‐term elevations of circulating Cort might exert on growth and development, when the physiological and behavioral abilities to cope with disturbance are limited. Two proximate hypotheses have been proposed to explain this age‐dependent pattern of Cort secretion. The Maturation Hypothesis proposes a progressive age‐related growth, maturation and enhanced sensitivity to sensory input of the Hypothalamic‐Pituitary‐Adrenal (HPA) axis tissues, whereas the Negative Feedback Attenuation Hypothesis proposes a gradual attenuation in the intensity of the negative feedback in the HPA axis. Here we tested these hypotheses by experimentally inducing negative feedback on the HPA axis via dexamethasone (DEX) treatment in nestling white storks Ciconia ciconia. Nestling age positively affected stress‐induced plasma Cort (STRESS‐Cort) levels during experimental handling and restraint, thus supporting the Developmental Hypothesis. DEX treatment significantly reduced STRESS‐Cort levels compared to saline (SAL) treatment, thus eliciting the expected negative feedback on the HPA axis. However, inter‐ and intra‐individual comparisons indicated no age effects on the intensity of the negative feedback exerted by DEX. Our results do not support the Negative Feedback Attenuation Hypothesis and suggest that progressive Maturation of the HPA axis tissues is the proximate mechanism responsible for age‐related changes in the stress response during avian post‐natal development. We encourage further tests of the proposed proximate mechanisms during migration, breeding and molt., This work was supported by the Spanish Ministry of Economy and Competitiveness and European funds (project CGL2012-32544 to J.B.) and the Spanish Ministry of Agriculture, Food and the Environment (Organismo Autónomo de Parques Nacionales, grant 511/2012 to J.B.), the University of Saskatchewan (Isabel Maria Lopez Martinez Memorial Scholarship to F.T-M), and the Spanish Council of Science CSIC (CSIC Projects 201730I011 and i-link 0564 to J.B.).

Nowadays, robotics education programs are used to promote the skills of students in STEM content at different levels of education for a wide variety of studies, not just engineering. This paper describes an educational program of robotics, applied precisely to the laboratory sessions of a robotics initiation course taught in the first year of a degree in Robotic Engineering, as well as the results of the application of that program in different academic years. The educational program contemplates that the students, grouped in work teams, have to design, assemble, and program a small mobile robot, destined to a final competition in which all the teams participate.

In birds, the use of corticosterone (Cort) implants is a frequent tool aimed at simulating systemic elevations of this hormone and studying effects on biological traits (e.g. physiology, morphology, behavior). This manipulation may alter adrenocortical function, potentially changing both baseline (Cort) and stress-induced (Cort) plasma Cort levels. However, implant effects on the latter trait are rarely measured, disregarding downstream consequences of potentially altered stress responses. Here, we analyzed the effects of Cort implants on both Cort and Cort in nestling and adult European white storks, Ciconia ciconia. In addition, we performed a review of 50 studies using Cort implants in birds during the last two decades to contextualize stork results, assess researchers' patterns of use and infer current study biases. High and low doses of Cort implants resulted in a decrease of both Cort (31-71% below controls) and Cort (63-79% below controls) in storks. Our literature review revealed that Cort generally increases (72% of experiments) whereas Cort decreases (78% of experiments) following implant treatment in birds. Our results challenge and expand the prevailing assumption that Cort implants increase circulating Cort levels because: (i) Cort levels show a quadratic association with implant dose across bird species, and decreased levels may occur at both high and low implant doses, and (ii) Cort implants also decrease Cort levels, thus producing stresshyporesponsive phenotypes. It is time to work towards a better understanding of the effects of Cort implants on adrenocortical function, before addressing downstream links to variation in other biological traits.

In birds, the use of corticosterone (Cort) implants is a frequent tool aimed at simulating systemic elevations of this hormone and studying effects on biological traits (e.g. physiology, morphology, behavior). This manipulation may alter adrenocortical function, potentially changing both baseline (BAS-Cort) and stress-induced (STRESS-Cort) plasma Cort levels. However, implant effects on the latter trait are rarely measured, disregarding downstream consequences of potentially altered stress responses. Here we analyzed the effects of Cort implants on both BAS-Cort and STRESS-Cort in nestling and adult European white storks Ciconia ciconia. In addition, we performed a review of 50 studies using Cort implants in birds during the last two decades to contextualize stork results, assess researchers' patterns of use and infer current study biases. High and low doses of Cort implants resulted in a decrease of both BAS-Cort (31-71% below controls) and STRESS-Cort (63-79% below controls) in storks. Our review revealed that BAS-Cort generally increases (72% of experiments) while STRESS-Cort decreases (78% of experiments) following implant treatment in birds. Our results challenge and expand the prevailing assumption that CORT implants increase circulating BAS-Cort levels because: (i) BAS-Cort levels show a quadratic association with implant dose across bird species, and decreased levels may occur at both high and low implant doses, and (ii) Cort implants also decrease STRESS-Cort levels, thus producing stress hyporesponsive phenotypes. It is time to work towards a better understanding of the effects of Cort implants on adrenocortical function, before addressing downstream links to variation in other biological traits.

Comunicacion presentada en IFAC International Workshops Intelligent Assembly and Disassembly (IAD'07), Intelligent Manufacturing Systems (IMS'07), 23-25 May 2007, Campus of San Vicente del Raspeig, Alicante, Spain

In this paper, a visual servoing for the tracking of objects in a plane using a fixed camera system is shown. The method proposed of tracking makes use of a variable number of trackers determined automatically. The integration of the predictions of each of them affords a flexible and robust system of tracking. The studies of efficiency carried out reflect that the delays produced are suitable for use in visual servoing. The proposed system can be generalized to tracking three-dimensional objects with movable cameras.

This paper presents a novel planner for dexterous manipulation with a multi-fingered robotic hand. This planner receives as input an initial grasp of the object and a desired trajectory of the object in task space (position and orientation). The planner computes the movements of the fingers which are required to move the object along this trajectory without breaking contacts. It uses a triangle mesh representation of the surfaces of the fingers and the object and a new contact evolution graph in order to compute all the possible transitions between the contact primitives of their surfaces. This planner have been implemented as a program which communicates with a five-fingered hand in order to test them in real manipulation tasks.

This paper presents a non-destructive disassembly method. It tries to make up for limitations of other methods based on contact surfaces. It uses a contact surfaces graph and shows an algorithm to obtain the movement sequence needed for the disassembly of two objects, using a composition of transfer movement. It performs a second filter to obtain the exact disassembly direction from the group of directions obtained from the contact surfaces. The filter employs a mobile robotic heuristic to feedback the contact surface graph throughout the disassembly process. The heuristic generates an environment map to infer the region where the probability of collision with the other objects is lower. To achieve the disassembly the paper presents a method for modeling the elements implied in the disassembly process. This virtual model of the environment allows us to quickly process the elements and the simulation of the movements for disassembly. This model can be used to either schedule the disassembly process or to test, during the design stage, whether the products can be easily disassembled.

Disassembly problem is a current issue for industrial companies. Governments of different countries promote research in this field. This paper presents the following points. First a brief state of the art in disassembly planning. Next it exposes a solution for the disassembly problem of industrial products. It uses a combination between direct and indirect graph representation for the product, all components that have physical entity are considered as vertices of the graph. Edges of the graph represent the relationships between vertices. There are three different types of edges. First corresponds with accessibility and fastener restrictions. Second corresponds with direct relations between components without fasteners. Last one corresponds with contact relationships, which represent an indifferent choice of the vertices. Based on that representation the paper exposed a method to find the best sequence to disassemble a component. Costs of disassembling each component and of changing tool between each pair of vertices and different sequences of the disassembly are taken into consideration. This method consists in a function minimization defined in the graph domain. In the last point of the paper this method is tested with a remote control disassembly. This method gives a solution to the problem, if several solutions, with the same cost, exist then it gives all of them, and any one of these disassemble sequences could be used to achieve to the target component.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The use of a robot arm for industry is a very common problem. A great quantity of these robots have to have a remote human controller to achieve its task successfully. The user knows what is happening with the robot arm through sensors. This information has to arrive to the user and if it consists of a video then the system needs a high bandwidth to carry it to the user in real-time. The present system uses a simulation feedback instead of video information; this type of feedback gets as much information as a video with a lower bandwidth. The simulation of the system is based on virtual reality modeling feedback language (VRML) to model the robot arm which reproduces the movements of the real robot. This method of feedback has the advantage of required little information to afford the user a real approach to the system. The proposed system lets the user move the robot arm with different point-to-point trajectories and different possibilities of movement. The aim of this kind of laboratory is to facilitate the access for students and professionals in the field of robotics. This system is used for teaching university students the themes of robotics. It improves the training of the students permitting them access to a real robot which would be impossible for universities to afford if each student needed his own robot to practice. This paper presents a remote laboratory approach for experimentation with a real robot, which uses the communication techniques of the web.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

An algorithm for allocating and scheduling tasks in multiprocessor environments is presented. Its main characteristic is its orientation towards machine vision applications. In this sense it deals with the peculiarities of systems which combine generic-type processors with Image Acquisition and Processing Boards. The main goal of the algorithm is total processing time reduction; such are the requirements when we deal with automated industrial inspection applications. By simultaneously tackling the phases of allocation and scheduling, the results obtained are better than those offered by traditional algorithms. The system is applied to a process of citrus fruit inspection, and its performances are also evaluated over randomly generated task graphs.

In this paper, we present the results of the extension of the mathematical morphology to color images by treating multi-channel data as vectors. The approach presented here uses the HSI and related color spaces (intuitives). A modification of the lexicographical order for vectorial processing is developed. The importance of this new method lies on automatic selection of elements of the HSI and related color spaces to form an ordering structure. The achievement of the algorithm is realized through the introduction of a weight factor to reduce the high preference of the first component of the classic lexicographical order. Experimental results demonstrate the improvement of this new method.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

This paper describes a vergence control algorithm for a 3D stereo recovery system. This work has been developed within framework of the project ROBTET. This project has the purpose of designing a Teleoperated Robotic System for live power lines maintenance. The tasks involved suppose the automatic calculation of path for standard tasks, collision detection to avoid electrical shocks, force feedback and accurate visual data, and the generation of collision free real paths. To accomplish these tasks the system needs an exact model of the environment that is acquired through an active stereoscopic head. A cooperative algorithm using vergence and stereo correlation is shown. The proposed system is carried out through an algorithm based on the phase correlation, trying to keep the vergence on the interest object. The sharp vergence changes produced by the variation of the interest objects are controlled through an estimation of the depth distance generated by a stereo correspondence system. In some elements of the scene, those aligned with the epipolar plane, large errors in the depth estimation as well as in the phase correlation, are produced. To minimize these errors a laser lighting system is used to help fixation, assuring an adequate vergence and depth extraction.

A fully integrated development tool for computer vision systems has been built in the framework of this paper. There are many applications that help the user in the design of such systems, using graphical interfaces and function libraries. Even in some cases, the final source code can be generated by these applications. This paper goes a step beyond; it allows the development of computer vision systems from a distributed environment. Besides, and as a distinctive characteristic with regard to other similar utilities, the system is able to automatically optimize task scheduling and assignment, depending on the available hardware.

In the last years aperture synthesis interferometric radiometers have received a special attention by space agencies as a feasible solution to passive monitoring of the Earth at low frequencies (L-band), where classical total power radiometers would require heavy steerable antennas to meet the spatial resolution requirements (10 - 20 Km), from a low polar orbit. While the performance of such instruments is well known in the radioastronomy field, its application to Earth remote sensing is quite new. The study of different array structures, system errors, calibration and inversion methods and instrument global performance requires the implementation of a simulator of a two-dimensional space borne interferometric radiometer. It allows us to analyze not only its snap shot radiometric accuracy, but also its improvement by means of pixel averaging, that is, the averaging of the common pixels recovered in a sequence of consecutive brightness temperature images. The simulations performed use the system parameters of the planned MIRAS (microwave imaging radiometer by aperture synthesis) instrument, a Y-shaped array with 43 antennas per arm spaced 0.89 lambda, currently under study by the European Space Agency.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Many inspection methods using computer vision have been developed, although in many of them the results obtained do not have the desired accuracy. In order to increase the system precision, two different solutions can be considered: the use of a more powerful image acquisition equipment and a solution that consists in developing algorithms that allow us to increase the accuracy of certain characteristics of the image. This paper is focused on setting a model that takes into account all the different signals involved in the image processing. It also defines the basis for the reconstruction of images in those areas with high content of information, such as edges, and more specifically those edges with a high change of intensity. In the image acquisition process, the input information is perfectly defined in a continuous domain and a discrete image is obtained as output, although distorted by the effects of the lenses, electrical sensor and the digitizer. This paper defines the conditions that the sampling process must satisfy in order to make possible the reconstruction of step edges using non-linear reconstruction filters in gray level images.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

This paper presents a method for minimizing the total elapsed time spent by n tasks running on m differents processors working in parallel. The developed algorithm not only minimizes the total elapsed time but also reduces the idle time and waiting time of in-process tasks. This condition is very important in some applications of computer vision in which the time to finish the total process is particularly critical -- quality control in industrial inspection, real- time computer vision, guided robots. The scheduling algorithm is based on the use of two matrices, obtained from the precedence relationships between tasks, and the data obtained from the two matrices. The developed scheduling algorithm has been tested in one application of quality control using computer vision. The results obtained have been satisfactory in the application of different image processing algorithms.

This paper presents a novel algorithm which registers pressure information from tactile sensors installed over the fingers of a robotic hand in order to perform manipulation tasks with objects. This algorithm receives as an input the joint trajectories of the fingers which have to be executed and adapts it to the real contact pressure of each finger in order to guarantee that undesired slippage or contact‐breaking is avoided during the execution of the manipulation task. This algorithm has been applied not only for the manipulation of normal rigid bodies but also for bodies whose centre of mass can be changed during the execution of the manipulation task. The research leading to the results presented in this paper has been funded by the research projects DPI2008‐02647and DPI2011‐22766 of the Spanish Ministry of Science and Innovation and by the research project GRE10‐16 of the University of Alicante. This research has also received funding from the European Community’s Seventh Framework Programme (FP7/2007‐2013) under Grant Agreement no. 231640 and the research project HANDLE.