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En este artículo se realiza el diseño e implementación de una plataforma de control simplificada para el control retroalimentado de un plotter CNC; se programa un controlador PID para el control de los servomotores el cual está basado en la programación a bloques en Simulink-Matlab. La retroalimentación se hace mediante la tarjeta de desarrollo del microcontrolador Atmel 2560 programado para adquirir los datos del encoder de un servomotor UNITEC. La validación experimental muestra que la integración de los diferentes módulos de muestreo en un bloque programado en Simulink-Matlab, simplifica el diseño electrónico de la conversión de señales, implementando por software muchas rutinas de conversión de señales, que antes no era posible de manera directa, facilitando a los investigadores el desarrollo y prueba de nuevos algoritmos de control en la plataforma de manera directa y en tiempo real.

Determining how ant colonies optimize foraging while mitigating pathogen and predator risks provides insight into how the ants have achieved ecological success. Ants must respond to changing resource conditions, but exploration comes at a cost of higher potential exposure to threats. Fungal infected cadavers surround the main foraging trails of the carpenter ant Camponotus rufipes, offering a system to study how foragers behave given the persistent occurrence of disease threats. Studies on social insect foraging behavior typically require many hours of human labor due to the high density of individuals. To overcome this, we developed deep learning based computer vision algorithms to track foraging ants, frame-by-frame, from video footage shot under the natural conditions of a tropical forest floor at night. We found that most foragers walk in straight lines overlapping the same areas as other ants, but there is a subset of foragers with greater exploration. Consistency in walking behavior may protect most ants from infection, while foragers that explore unique portions of the trail may be more likely to encounter fungal spores implying a trade-off between resource discovery and risk avoidance.

espanolEste articulo analiza el repertorio de practicas de asistencia a las victimas de violaciones a los derechos humanos llevado a cabo por asistentes sociales de la Vicaria de la Solidaridad durante la dictadura. En este repertorio, que transformo los saberes disciplinarios y tuvo implicancias eticas sin precedentes, se analiza aspectos relativos a una performatividad testimonial de la escucha, las acciones de resistencia mediante la creacion de alianzas colectivas y la conformacion de un acervo documental, cuya custodia concita practicas de mediacion y resguardo hereditarias de aquellas de asistencia conformadas en el pasado. EnglishThis article analyzes the repertoire of assistance practices for victims of human rights violations carried out by social workers of the Vicaria de la Solidaridad during the dictatorship. Within this repertoire, which transformed the disciplinary knowledge and had unprecedented ethical implications, we approach testimonial performativity through the listening that the social workers were willing to give to the victims, the actions of resistance through the creation of collective alliances and the creation of a documentary collection. At the same time the custody of the archives reproduces the practice of mediation and supporting practices from the past.

Obra ressenyada: Freddy TIMMERMANN, El Gran Terror. Miedo, emoción y discurso. Chile, 1973-1980 . Santiago de Chile: Copygraph., 2014.

Resumen: El presente artículo analiza la relación entre espacio geográfico y memoria en los testimonios de prisión política que relatan la experiencia de reclusión en el campo de prisioneros de isla Dawson, durante la dictadura cívico-militar chilena. El artículo propone que estos testimonios elaboran una memoria geográfica, manifiesta en el recuerdo del contacto y la relación que los prisioneros establecieron con el contexto geográfico en una de las zonas más australes del mundo. A la vez que, en el marco más amplio de las memorias del terrorismo de Estado, se constituye una memoria del presidio geográfico, en la que confluyen el recuerdo de la violencia con la cual colaboran las condiciones climáticas y topográficas de la isla, junto a experiencias de liberación subjetiva y discreta autonomía, manifiestas en el recuerdo de la contemplación de la naturaleza del entorno, advirtiendo una dimensión benéfica en aquella rememoración. Esto abre la posibilidad de ampliar la relación entre espacio y memoria, en la cual se encuentren el análisis espacial aportado por la geografía y el interés por los procesos de recuerdo propio del campo de estudio de las memorias colectivas. Abstract: This article analyzes the relationship between geographic space and memory in the testimonies of political prisoners, that relate the experience of detention in the prison camp of Dawson Island, during the Chilean civic-military dictatorship. The article proposes that these testimonies elaborate a geographical memory, manifested in memories of the contact and relationship that the prisoners established with the geographical context in one of the southernmost areas of the world. At the same time, within the broader framework of State terror memories, a memory of the geographic imprisonment is constituted. Here, memories of the violence, with which the climatic and topographic conditions of the island collaborate, appear alongside experiences of subjective liberation and discreet autonomy, manifest in memories of contemplation of nature, noticing a beneficial dimension in that remembrance. This opens the possibility of expanding the relationship between space and memory, where spatial analysis from geography works together with the interest in the processes of remembrance characteristic of the collective memory field of studies.

Significance Microbial parasites may behave collectively to manipulate their host’s behavior. We examine adaptations of a microbial parasite in its natural environment: the body of its coevolved and manipulated host. Electron microscopy and 3D reconstructions of host and parasite tissues reveal that this fungus invades muscle fibers throughout the ant’s body but leaves the brain intact, and that the fungal cells connect to form extensive networks. The connections are likened to structures that aid in transporting nutrients and organelles in several plant-associated fungi. These findings alter the current view of parasite-extended phenotypes by demonstrating that behavior control does not require the parasite to physically invade the host brain and that parasite cells may coordinate to change host behavior., Some microbes possess the ability to adaptively manipulate host behavior. To better understand how such microbial parasites control animal behavior, we examine the cell-level interactions between the species-specific fungal parasite Ophiocordyceps unilateralis sensu lato and its carpenter ant host (Camponotus castaneus) at a crucial moment in the parasite’s lifecycle: when the manipulated host fixes itself permanently to a substrate by its mandibles. The fungus is known to secrete tissue-specific metabolites and cause changes in host gene expression as well as atrophy in the mandible muscles of its ant host, but it is unknown how the fungus coordinates these effects to manipulate its host’s behavior. In this study, we combine techniques in serial block-face scanning-electron microscopy and deep-learning–based image segmentation algorithms to visualize the distribution, abundance, and interactions of this fungus inside the body of its manipulated host. Fungal cells were found throughout the host body but not in the brain, implying that behavioral control of the animal body by this microbe occurs peripherally. Additionally, fungal cells invaded host muscle fibers and joined together to form networks that encircled the muscles. These networks may represent a collective foraging behavior of this parasite, which may in turn facilitate host manipulation.

Some parasites have evolved the ability to adaptively manipulate host behavior. One notable example is the fungus Ophiocordyceps unilateralis sensu lato, which has evolved the ability to alter the behavior of ants in ways that enable fungal transmission and lifecycle completion. Because host mandibles are affected by the fungi, we focused on understanding changes in the metabolites of muscles during behavioral modification. We used High-Performance Liquid Chromatography-Mass/Mass (HPLC-MS/MS) to detect the metabolite difference between controls and O. unilateralis-infected ants. There was a significant difference between the global metabolome of O. unilateralis-infected ants and healthy ants, while there was no significant difference between the Beauveria bassiana treatment ants group compared to the healthy ants. A total of 31 and 16 of metabolites were putatively identified from comparisons of healthy ants with O. unilateralis-infected ants and comparisons of B. bassiana with O. unilateralis-infected samples, respectively. This result indicates that the concentrations of sugars, purines, ergothioneine, and hypoxanthine were significantly increased in O. unilateralis-infected ants in comparison to healthy ants and B. bassiana-infected ants. This study provides a comprehensive metabolic approach for understanding the interactions, at the level of host muscles, between healthy ants and fungal parasites.

There are numerous examples of parasites that manipulate the behavior of the hosts that they infect. One such host–pathogen relationship occurs between the ‘zombie-ant fungus’ Ophiocordyceps unilateralis sensu lato and its carpenter ant host. Infected ants climb to elevated locations and bite onto vegetation where they remain permanently affixed well after death. The mandibular muscles, but not the brain, of infected ants are extensively colonized by the fungus. We sought to investigate the mechanisms by which O. unilateralis s.l. may be able to influence mandibular muscle contraction despite widespread muscle damage. We found that infected muscles show evidence of hypercontraction. Despite the extensive colonization, both motor neurons and neuromuscular junctions appear to be maintained. Infection results in sarcolemmal damage, but this is not specific to the death grip. We found evidence of precise penetration of muscles by fungal structures and the presence of extracellular vesicle-like particles, both of which may contribute to mandibular hypercontraction.

RESUMEN Este artículo analiza el repertorio de prácticas de asistencia a las víctimas de violaciones a los derechos humanos llevado a cabo por asistentes sociales de la Vicaría de la Solidaridad durante la dictadura. En este repertorio, que transformó los saberes disciplinarios y tuvo implicancias éticas sin precedentes, se analiza aspectos relativos a una performatividad testimonial de la escucha, las acciones de resistencia mediante la creación de alianzas colectivas y la conformación de un acervo documental, cuya custodia concita prácticas de mediación y resguardo hereditarias de aquellas de asistencia conformadas en el pasado.

RESUMEN Este artículo analiza el repertorio de prácticas de asistencia a las víctimas de violaciones a los derechos humanos llevado a cabo por asistentes sociales de la Vicaría de la Solidaridad durante la dictadura. En este repertorio, que transformó los saberes disciplinarios y tuvo implicancias éticas sin precedentes, se analiza aspectos relativos a una performatividad testimonial de la escucha, las acciones de resistencia mediante la creación de alianzas colectivas y la conformación de un acervo documental, cuya custodia concita prácticas de mediación y resguardo hereditarias de aquellas de asistencia conformadas en el pasado. ABSTRACT This article analyzes the repertoire of assistance practices for victims of human rights violations carried out by social workers of the Vicaría de la Solidaridad during the dictatorship. Within this repertoire, which transformed the disciplinary knowledge and had unprecedented ethical implications, we approach testimonial performativity through the listening that the social workers were willing to give to the victims, the actions of resistance through the creation of collective alliances and the creation of a documentary collection. At the same time the custody of the archives reproduces the practice of mediation and supporting practices from the past.

Some parasites can manipulate the behavior of their animal hosts to increase transmission. An interesting area of research is understanding how host neurobiology is manipulated by microbes to the point of displaying such aberrant behaviors. Here, we characterize the metabolic profile of the brain of an insect at the moment of the behavioral manipulation by a parasitic microbe. Our model system are ants infected with the parasitic fungus Ophiocordyceps kimflemingiae (=unilateralis), which manipulates ants to climb and bite into plant substrates, before killing the host (i.e. zombie ants). At the moment of the behavioral manipulation by the fungus, the host's brain is not invaded by the fungus which is known to extensively invade muscle tissue. We found that, despite not being invaded by the parasite, the brains of manipulated ants are notably different, showing alterations in neuromodulatory substances, signs of neurodegeneration, changes in energy use, and antioxidant compound that signal stress reactions by the host. Ergothionine, a fungal derived compound with known neuronal cytoprotection functions was found to be highly elevated in zombie ant brains suggesting the fungus, which does not invade the central nervous system, is preserving the brain.

Determining how ant colonies optimize foraging while mitigating disease risk provides insight into how the ants have achieved ecological success. Fungal infected cadavers surround the main foraging trails of the carpenter antCamponotus rufipes, offering a system to study how foragers behave given the persistent occurrence of disease threats. Studies on social insect foraging behavior typically require many hours of human labor due to the high density of individuals. To overcome this, we developed deep learning based computer vision algorithms to track foraging ants, frame-by-frame, from video footage. We found foragers can be divided into behavioral categories based on how straight they walk across the trail. Eighty percent of ants walk directly across the trail, while 20% wander or circle when crossing the trail. Departure from the main trail encourages exploration of new areas and could enhance discovery of new food resources. Conversely, results from our agent-based model simulations suggest deviation from a straight path exposes foragers to more infectious fungal spores. Consistency in walking behavior may protect most ants from infection, while the foragers with increased exposure due to their mode of walking could be a sufficient number of new hosts to sustain disease in this environment.

Environmental conditions exert strong selection on animal behavior. We tested the hypothesis that the altered behavior of hosts due to parasitic manipulation is also subject to selection imposed by changes in environmental conditions over time. Our model system is ants manipulated by parasitic fungi to bite onto vegetation. We analyzed the correlation between forest type (tropical vs. temperate) and biting substrate (leaf vs. twigs), the time required for the fungi to reach reproductive maturity, and the phylogenetic relationship among specimens from tropical and temperate forests in different parts of the globe. We show that the fungal development in temperate forest is longer than the period of time leaves are present and the ants are manipulated to bite twigs. When biting twigs, 90% of the we examined dead ants had their legs wrapped around twigs, which appears to provide better attachment to the plant. Ancestral state character reconstruction suggests that the leaf biting is the ancestral trait and that twig biting is a convergent trait in temperate regions of the globe. These three lines of evidence suggest that changes in environmental conditions have shaped the manipulative behavior of the host by its parasite.

Parasites can manipulate the behavior of their hosts in ways that increase either their direct fitness or transmission to new hosts. The Kingdom Fungi have evolved a diverse array of strategies to manipulate arthropod behavior resulting in some of the most complex and impressive examples of behavioral manipulation by parasites. Here we provide an overview of these different interactions and discuss them from an evolutionary perspective. We discuss parasite manipulation within the context of Niko Tinbergen's four questions (function, phylogeny, causation, and ontogeny) before detailing the proximate mechanisms by which fungi control arthropod behavior and the evolutionary pathways to such adaptations. We focus on some systems for which we have recently acquired new knowledge (such as the zombie ant fungus, Ophiocordyceps unilateralis s.l.), but a major goal is also to highlight how many interesting examples remain to be discovered and investigated. With this in mind, we also discuss likely examples of manipulated spiders that are largely unexplored ("zombie spiders"). Armed with advanced tools in evolutionary biology (from serial block face SEM to RNAseq) we can discover how the fungi, a group of microbes capable of coordinated activity, have evolved the ability to direct animal behavior. In short, we have the ability to understand how the organism without the brain controls the one with the brain. We hope such a goal, coupled with the knowledge that many diverse examples of control exist, will inspire other organismal biologists to study the complex adaptations that have arisen from "so simple a beginning."

It is assumed that social life can lead to the rapid spread of infectious diseases and outbreaks. In ants, disease outbreaks are rare and the expression of collective behaviors is invoked to explain the absence of epidemics in natural populations. Here, we address the ecological approach employed by many studies that have notably focused (89% of the studies) on two genera of generalist fungal parasites (Beauveria and Metarhizium). We ask whether these are the most representative models to study the evolutionary ecology of ant-fungal parasite interactions. To assess this, we critically examine the literature on ants and their interactions with fungal parasites from the past 114years (1900-2014). We discuss how current evolutionary ecology approaches emerged from studies focused on the biological control of pest ants. We also analyzed the ecological relevance of the laboratory protocols used in evolutionary ecology studies employing generalist parasites, as well as the rare natural occurrence of these parasites on ants. After a detailed consideration of all the publications, we suggest that using generalist pathogens such as Beauveria and Metarhizium is not an optimal approach if the goal is to study the evolutionary ecology of disease in ants. We conclude by advocating for approaches that incorporate greater realism.

Parasites can manipulate the behavior of their hosts in ways that increase either their direct fitness or transmission to new hosts. The Kingdom Fungi have evolved a diverse array of strategies to manipulate arthropod behavior resulting in some of the most complex and impressive examples of behavioral manipulation by parasites. Here we provide an overview of these different interactions and discuss them from an evolutionary perspective. We discuss parasite manipulation within the context of Niko Tinbergen's four questions (function, phylogeny, causation, and ontogeny) before detailing the proximate mechanisms by which fungi control arthropod behavior and the evolutionary pathways to such adaptations. We focus on some systems for which we have recently acquired new knowledge (such as the zombie ant fungus, Ophiocordyceps unilateralis s.l.), but a major goal is also to highlight how many interesting examples remain to be discovered and investigated. With this in mind, we also discuss likely examples of manipulated spiders that are largely unexplored ("zombie spiders"). Armed with advanced tools in evolutionary biology (from serial block face SEM to RNAseq) we can discover how the fungi, a group of microbes capable of coordinated activity, have evolved the ability to direct animal behavior. In short, we have the ability to understand how the organism without the brain controls the one with the brain. We hope such a goal, coupled with the knowledge that many diverse examples of control exist, will inspire other organismal biologists to study the complex adaptations that have arisen from "so simple a beginning."

It is assumed that social life can lead to the rapid spread of infectious diseases and outbreaks. In ants, disease outbreaks are rare and the expression of collective behaviors is invoked to explain the absence of epidemics in natural populations. Here, we address the ecological approach employed by many studies that have notably focused (89% of the studies) on two genera of generalist fungal parasites ( Beauveria and Metarhizium ). We ask whether these are the most representative models to study the evolutionary ecology of ant–fungal parasite interactions. To assess this, we critically examine the literature on ants and their interactions with fungal parasites from the past 114 years (1900–2014). We discuss how current evolutionary ecology approaches emerged from studies focused on the biological control of pest ants. We also analyzed the ecological relevance of the laboratory protocols used in evolutionary ecology studies employing generalist parasites, as well as the rare natural occurrence of these parasites on ants. After a detailed consideration of all the publications, we suggest that using generalist pathogens such as Beauveria and Metarhizium is not an optimal approach if the goal is to study the evolutionary ecology of disease in ants. We conclude by advocating for approaches that incorporate greater realism.

Este artículo da cuenta de hallazgos de una investigación FONDECYT (N°1120425) que se propuso conocer cómo hombres y mujeres han experimentado y han sido parte de los cambios estructurales, sociales y culturales ocurridos en diferentes lugares de Chile Central a partir de la segunda mitad del siglo XX hasta la actualidad. Para ello se ha privilegiado técnicas cualitativas como entrevistas en profundidad a hombres y mujeres de distintas edades y la aplicación del método genealógico a tres generaciones en dos grupos de parentesco residentes en áreas de riego y secano. This paper presents discoveries of a FONDECYT (N° 1120425) investigation that intended to know how men and women have experienced and how they have been part of the structural, social and cultural changes occurred in different places of Central Chile in the last fifty years, giving priority to qualitative methods as interviews to men and women of different ages and the use of the genealogical method for three generations in two groups of relationship residents in irrigated and unirrigated land. Este artigo relata os resultados de uma pesquisa FONDECYT (No. 1120425), que é a de saber como os homens e mulheres têm experimentado e sido parte das mudanças estruturais, sociais e culturais acontecidos em diferentes partes do Chile Central desde a segunda metade do século XX até o presente. Para isso temos privilegiado técnicas qualitativas tais como entrevistas em profundidade com homens e mulheres de diferentes idades e a aplicação do método genealógico a três gerações em dois grupos de parentesco residentes em áreas irrigadas e sem irrigação.

Background Adaptive manipulation of animal behavior by parasites functions to increase parasite transmission through changes in host behavior. These changes can range from slight alterations in existing behaviors of the host to the establishment of wholly novel behaviors. The biting behavior observed in Carpenter ants infected by the specialized fungus Ophiocordyceps unilateralis s.l. is an example of the latter. Though parasitic manipulation of host behavior is generally assumed to be due to the parasite’s gene expression, few studies have set out to test this. Results We experimentally infected Carpenter ants to collect tissue from both parasite and host during the time period when manipulated biting behavior is experienced. Upon observation of synchronized biting, samples were collected and subjected to mixed RNA-Seq analysis. We also sequenced and annotated the O. unilateralis s.l. genome as a reference for the fungal sequencing reads. Conclusions Our mixed transcriptomics approach, together with a comparative genomics study, shows that the majority of the fungal genes that are up-regulated during manipulated biting behavior are unique to the O. unilateralis s.l. genome. This study furthermore reveals that the fungal parasite might be regulating immune- and neuronal stress responses in the host during manipulated biting, as well as impairing its chemosensory communication and causing apoptosis. Moreover, we found genes up-regulated during manipulation that putatively encode for proteins with reported effects on behavioral outputs, proteins involved in various neuropathologies and proteins involved in the biosynthesis of secondary metabolites such as alkaloids. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1812-x) contains supplementary material, which is available to authorized users.

The development of techniques capable of evaluating deterioration of reinforced concrete (RC) structures is instrumental to the advancement of techniques for the structural health monitoring (SHM) and service life estimate for constructed facilities. One of the main causes leading to degradation of RC is the corrosion of the steel reinforcement. This process can be modeled phenomenologically, while laboratory tests aimed at studying durability responses are typically accelerated in order to provide useful results within a realistic period of time. To assess the condition of damage in RC, a number of nondestructive methods have been recently studied. Acoustic emission (AE) is emerging as a nondestructive tool to detect the onset and progression of deterioration mechanisms. In this paper, the development of accelerated corrosion and continuous AE monitoring test set-up for RC specimens are presented. Relevant information are provided with regard to the characteristics of the corrosion circuit, continuous measurement and acquisition of corrosion potential, selection of AE sensors and AE parameter setting. The effectiveness of the setup in detecting and characterizing the initiation and progression of the corrosion phenomenon is discussed on the basis of preliminary results from small-scale, pre-cracked RC specimens, which are representative of areas near the clear cover in typical RC bridge members.

Despite the widely held position that the social insects have evolved effective ways to limit infectious disease spread, many pathogens and parasites do attack insect societies. Maintaining a disease-free nest environment is an important evolutionary feature, but since workers have to leave the nest to forage they are routinely exposed to disease. Here we show that despite effective social immunity, in which workers act collectively to reduce disease inside the nest, 100% of studied ant colonies of Camponotus rufipes in a Brazilian Rainforest were infected by the specialized fungal parasite Ophiocordyceps unilateralis s.l. Not only is disease present for all colonies but long-term dynamics over 20 months revealed disease is a permanent feature. Using 3D maps, we showed the parasite optimizes its transmission by controlling workers’ behavior to die on the doorstep of the colony, where susceptible foragers are predictable in time and space. Therefore, despite social immunity, specialized diseases of ants have evolved effective strategies to exploit insect societies.

Many studies have investigated how social insects behave when a parasite is introduced into their colonies. These studies have been conducted in the laboratory, and we still have a limited understanding of the dynamics of ant-parasite interactions under natural conditions. Here we consider a specialized parasite of ant societies (Ophiocordyceps camponoti-rufipedis infecting Camponotus rufipes) within a rainforest. We first established that the parasite is unable to develop to transmission stage when introduced within the host nest. Secondly, we surveyed all colonies in the studied area and recorded 100% prevalence at the colony level (all colonies were infected). Finally, we conducted a long-term detailed census of parasite pressure, by mapping the position of infected dead ants and foraging trails (future hosts) in the immediate vicinity of the colonies over 20 months. We report new dead infected ants for all the months we conducted the census – at an average of 14.5 cadavers/month/colony. Based on the low infection rate, the absence of colony collapse or complete recovery of the colonies, we suggest that this parasite represents a chronic infection in the ant societies. We also proposed a “terminal host model of transmission” that links the age-related polyethism to the persistence of a parasitic infection.

Trail-making ants lay pheromones on the substrate to define paths between foraging areas and the nest. Combined with the chemistry of these pheromone trails and the physics of evaporation, trail-laying and trail-following behaviours provide ant colonies with the quickest routes to food. In relatively uniform environments, such as that provided in many laboratory studies of trail-making ants, the quickest route is also often the shortest route. Here, we show that carpenter ants (Camponotus rufipes), in natural conditions, are able to make use of apparent obstacles in their environment to assist in finding the fastest routes to food. These ants make extensive use of fallen branches, twigs and lianas as bridges to build their trails. These bridges make trails significantly longer than their straight line equivalents across the forest floor, but we estimate that ants spend less than half the time to reach the same point, due to increased carriage speed across the bridges. We also found that these trails, mainly composed of bridges, are maintained for months, so they can be characterized as trunk trails. We suggest that pheromone-based foraging trail networks in field conditions are likely to be structured by a range of potentially complex factors but that even then, speed remains the most important consideration.

Despite the growing number of experimental studies on mechanisms of social immunity in ant societies, little is known about how social behavior relates to disease progression within the nests of ants. In fact, when empirically studying disease in ant societies, it is common to remove dead ants from experiments to confirm infection by the studied parasite. This unfortunately does not allow disease to progress within the nest as it may be assumed would happen under natural conditions. Therefore, the approach taken so far has resulted in a limited knowledge of diseases dynamics within the nest environment. Here we introduced a single infectious cadaver killed by the fungus Beauveria bassiana into small nests of the ant Camponotus castaneus. We then observed the natural progression of the disease by not removing the corpses of the ants that died following the first entry of the disease. Because some behaviors such as social isolation of sick individuals or the removal of cadavers by nestmates are considered social immune functions and thus adaptations at the colony level that reduce disease spread, we also experimentally confined some sub-colonies to one or two chamber nests to prevent the expression of such behaviors. Based on 51 small nests and survival studies in 1,003 ants we found that a single introduced infectious cadaver was able to transmit within the nest, and social immunity did not prevent the collapse of the small sub-colonies here tested. This was true whether ants did or did not have the option to remove the infectious cadaver. Therefore, we found no evidence that the typically studied social immunity behaviors can reduce disease spread in the conditions here tested.

In this work a Proportional Derivative (PD) image-based visual servoing scheme applied to planar robot manipulators with revolute joints is proposed. Damping is added at the joint level using the robot active joints. The proposed control law may be though as a velocity inner loop at the joint level implementing the derivative action and a visual outer loop at the task level performing the proportional action. Since it is assumed that velocity measurements are not available, velocity estimates are obtained from active joint position measurements using a linear filter. Another feature of the proposed approach is the fact that calibration procedures for the vision system are avoided since an image-based approach is adopted. Closed loop stability is studied using Lyapunov Stability Theory. Experimental results on a laboratory prototype validates the proposed approach, moreover, it is also experimentally shown that by using a vision system for measurement of the robot end effector, kinematics errors may be tolerated in contrast with control strategies making use of the direct kinematics where performance depends on the precise knowledge of the robot kinematics.

This paper proposes a stable Proportional Derivative Controller applied to redundantly actuated parallel robots with uncertainty in the kinematic parameters. It is shown that all the closed loop signals are uniformly ultimately bounded. Gravitational terms are approximated using a Radial Basis Function Neural Network with joint information feeding their activation functions and with on-line real-time learning. A depart from current approaches is the fact that damping is added at the joint level using the robot active joints and the fact that it does not require the exact knowledge of the kinematic parameters. The learning rule for the neural network weights is obtained from a Lyapunov stability analysis. Simulation results are reported and demonstrate the effectiveness of the proposed controller.

In this paper, we propose a stable neurovisual servoing algorithm for set-point control of planar robot manipulators in a fixed-camera configuration an show that all the closed-loop signals are uniformly ultimately bounded (UUB) and converge exponentially to a small compact set. We assume that the gravity term and Jacobian matrix are unknown. Radial basis function neural networks (RBFNNs) with online real-time learning are proposed for compensating both gravitational forces and errors in the robot Jacobian matrix. The learning rule for updating the neural network weights, similar to a back propagation algorithm, is obtained from a Lyapunov stability analysis. Experimental results on a two degrees of freedom manipulator are presented to evaluate the proposed controller.

This paper proposes a stable neurocontroller for set-point control of robot manipulators in task space without any a priori knowledge on the Jacobian matrix. A wavelet neural network (WNN) with task information feeding their activation functions and with on-line real-time learning is applied to approximate an unknown nonlinear function. The WNN generates control input signals designed using Lyapunov stability theory to guarantee that all the closed loop signals are uniformly ultimately bounded. Simulation results using a two degrees of freedom robot are presented to evaluate the proposed controller.

In this work a stable neuro PD controller for set point control of planar robot manipulators in task space is proposed. The gravity t erms and the robot Jacobian matrix are assumed unknown. Gravitational terms are approximated using Radial Basis Functions Neural Network with task or joint information feeding the activation functions and with on-line real-time learning. suacient c onditions for the bound on the estimated Jacobian matrix and stability c ondition far the feedback gains are presented to guarantee that all the closed loop signals are uniformly ultimately bounded. Experimental results in a two degrees of freedom robot are presented to evaluate the proposed contro I ler.

In this work a stable task space neuro algorithm for set-point control of robot manipulators with uncertain parameters is proposed. A depart from current approaches is the fact that a Wavelet Neural Network with on-line real-time learning seeks to explicitly compensate both the unknown gravity terms and the mismatch between the true and the estimated Jacobian matrix and the fact that it does not need velocity measurements. Linear position filtering is used to estimated the robot joint velocity in the control law and the properties of the Wavelet Neural Network are employed for avoiding velocity measurements in the learning rule. It is shown that all the closed loop signals are uniformly ultimately bounded. Experimental results in a two degrees of freedom robot are presented to evaluate the proposed controller.