521 research outputs found
Coordinated transportation with minimal explicit communication between robots
PreprintWe propose and demonstrate how attractor dynamics can be used to
design and implement a distributed dynamic control architecture that enables
a team of two robots, without force/torque sensors and equipped solely with
low-level sensors, to carry a long object and simultaneously avoid obstacles. The
explicit required communication between robots is minimal. The robots have no
prior knowledge of their environment. Experimental results in indoor environments
show that if parameter values are chosen within reasonable ranges then the overall
system works quite well even in cluttered environments. The robotsâ behavior is
stable and the generated trajectories are smooth
Determinants of merger and acquisition activity in the renewable energy industry in the United States of America
For the past few decades, the renewable energy industry has grown and expanded its influence and competitiveness in global markets. This thesis analysis whether certain factors related to the energy industry are conducive to mergers and acquisitions. Using regression analysis, it concludes that solar industry growth, power industry growth, and crude oil prices have no impact on M&A activity on the given timeframe
Integrating verbal and nonverbal communication in a dynamic neural field architecture for humanârobot interaction
How do humans coordinate their intentions, goals and motor behaviors when performing joint action tasks? Recent experimental evidence suggests that resonance processes in the observerâs motor system are crucially involved in our ability to understand actions of othersâ, to infer their goals and even to comprehend their action-related language. In this paper, we present a control architecture for humanârobot collaboration that exploits this close perception-action linkage as a means to achieve more natural and efficient communication grounded in sensorimotor experiences. The architecture is formalized by a coupled system of dynamic neural fields representing a distributed network of neural populations that encode in their activation patterns goals, actions and shared task knowledge. We validate the verbal and nonverbal communication skills of the robot in a joint assembly task in which the humanârobot team has to construct toy objects from their components. The experiments focus on the robotâs capacity to anticipate the userâs needs and to detect and communicate unexpected events that may occur during joint task execution.Fundação para a CiĂȘncia e a Tecnologia (FCT) - Bolsa POCI/V.5/A0119/2005 and CONC-REEQ/17/2001European Commission through the project JAST (IP-003747
Brazilian economy and real estate: a synthesis of the last decades
Como desdobramento da pesquisa realizada para obtenção do tĂtulo de mestre por um dos autores, ambos os autores discorrem nesse artigo sobre os principais eventos econĂŽmicos e marcos regulatĂłrios que ocorreram nas Ășltimas dĂ©cadas no Brasil e em SĂŁo Paulo e o desenvolvimento do mercado imobiliĂĄrio face a esses acontecimentos.A partir da criação do Banco Nacional da Habitação, na dĂ©cada de 1960, atĂ© o recente ĂȘxito produtivo do Programa Minha Casa, Minha Vida; considerando, nesse Ănterim, eventos econĂŽmicos nacionais e polĂticas federais e municipais (na cidade de SĂŁo Paulo), esses acontecimentos sĂŁo sintetizados em ordem cronolĂłgica, com o intuito de ressaltar a importĂąncia da economia sobre a produção urbana residencial, particularmente a realizada pela iniciativa privada.As a result of the research carried out to obtaining the title of master by one of the authors, both the authors comment in this article on the major economic events and regulatory systems, which occurred in recent decades paragraph Brazil and Sao Paulo, and the development of the real estate, in the face of these events.From the creation of the Bank National Housing (BNH), in the 1960s, to the recent production success of Program My House, My Life (PMHML); whereas in the interim, economic events national and federal and municipal policies (in the city of Sao Paulo), these events are summarized in chronological order, in order to highlight the importance of the economy on residential urban production, particularly carried out by private initiative.Â
A dynamic field approach to goal inference and error monitoring for human-robot interaction
In this paper we present results of our ongoing research on non-verbal human-robot interaction that is heavily inspired by recent experimental findings about the neuro-cognitive mechanisms supporting joint action in humans. The robot control architecture implements the joint coordination of actions and goals as a dynamic process that integrates contextual cues, shared task knowledge and the predicted outcome of the userâs motor behavior. The architecture
is formalized by a coupled system of dynamic neural fields representing
a distributed network of local but connected neural populations with specific functionalities. We validate the approach in a task in which a robot and a human user jointly construct a toy âvehicleâ. We show that the context-dependent mapping from action observation onto appropriate complementary actions allows the robot to cope with dynamically changing joint action situations. This includes a basic form of error monitoring and compensation.Fundação para a CiĂȘncia e a Tecnologia (FCT) - POCI/V.5/A0119/2005, CONC-REEQ/17/200
The Role of Saliva in Food Sensory Perception: Relevant Knowledge to Design Healthy Foods
Food choices and consumption are determined by a range of factors that contribute to aversion or pleasure and guide to
final intake. Among these, the sensorial characteristics of food have a major and decisive role in choice behaviour.
Although some of the mechanisms involved in oral food perception, namely in taste and astringency perception, are
considerable known, many questions remains, particularly in what concerns variations among individuals in their
sensitivity for food sensorial aspects. The understanding of the mechanisms leading to different responses for the same
sensorial stimulus is particularly important to understand food choices.
Bitter has been the basic taste most studied for variations among individuals in perception and in how this influences food
behaviour and nutritional status. The observation, at several years ago, that some individuals are very sensitive to the
bitterness of the compounds phenyl thiocarbamide (PTC) or 6-n-propylthyouracil (PROP), whereas others are almost
insensitive, triggered the emergence of diverse studies about the motif for that, resulting in the identification of gene
polymorphisms for the bitter taste receptor TAS2R38. Subsequently to that, polymorphisms for other receptors and taste
qualities have been identified. Even so, these genetic variations are not able to explain the total diversity in taste/oral
sensations responses. In recent years, it has begun to become apparent that saliva has a relevant role in taste recognition
mechanisms. Apart from astringency, which is well known to depend on salivary proteins to develop and being perceived,
basic tastes started to be related with saliva composition. Some salivary proteins, among which carbonic anhydrase VI,
cystatins, amylase and others, have been observed to relate with taste perception. However, saliva secretion changes with
taste stimulation and according dietary habits. Moreover, body weight condition, metabolic status or diverse pathologies
are responsible for changes in saliva composition. Being this fluid important in modulating oral food perception, to know
individualsâ saliva composition becomes of interest for modulating or directing choices. Based on the literature and recent
scientific results, the role of saliva in food sensory perception will be discussed according to these two angles. The
question of the high between-subject variability in view of saliva properties and its consequence on perception will be
emphasized.Acknowledgements This article was funded by FCT-Science and Technology Foundation as part of Project UID/AGR/00115/2013.
Funding was additionally provided by the FCT-Portuguese Science Foundation: research contract IF/01778/2013-Elsa Lamy, while
FCT was not involved in carrying out this study or submitting it for publication
Endothelial dysfunction in type 2 diabetes: effect of antioxidants
Individuals with insulin resistance and diabetes mellitus have increased cardiovascular morbidity and mortality, caused in part by vascular complications. Endothelial dysfunction has been implicated in the pathogenesis of vascular diabetic disease. This abnormal function of the vasculature precedes cardiovascular disease and is associated with impaired endothelium-dependent vasorelaxation. The main etiology of the increased mortality and morbidity of type 2 diabetic patients is atherosclerosis. Increased production of free radicals is associated with the pathophysiology of diabetes, resulting in oxidative damage to lipids and proteins. Reduction of oxidative stress in diabetic patients may delay the onset of atherogenesis and the appearance of micro- and macrovascular complications. Alpha-lipoic acid (LA) is a multifunctional antioxidant that has been shown to have beneficial effects on polyneuropathy and on markers of oxidative stress in various tissues. This study was conducted to investigate the effects of LA on endothelial function in diabetic and hyperlipidemic animal models. Carbohydrate and lipid metabolism, endothelial function, plasma malondialdehyde (MDA) and urinary 8-hydroxydeoxyguanosine (8-OHdG) were assessed in non-diabetic controls (Wistar rats), untreated diabetic Goto-Kakizaki (GK) rats and, atherogenic diet (AD)-fed GK rats (fed with atherogenic diet only, treated with alpha-lipoic acid and treated with vehicle, for 3 months). AD resulted in a 3-fold increase in both total and non-HDL serum cholesterol levels and in a 2-fold increase triglyceride levels while endothelial function was significantly reduce MDA and 8-OHdG levels were higher in the GK and GK hyperlipidemic groups and were completely reversed by the antioxidant. Hyperlipidemic GK diabetic rats showed significantly reduced endothelial function that was partially improved with LA. Furthermore, lipoic acid significantly reduced serum cholesterol levels, without lowering HDL cholesterol. Alpha-lipoic acid supplementation represents an achievable adjunct therapy to improve endothelial function and reduce oxidative stress, factors that are implicated in the pathogenesis of atherosclerosis in diabetes
Neuro-cognitive mechanisms of decision making in joint action: A human-robot interaction study
In this paper we present a model for action preparation and decision making in cooperative tasks that is inspired by recent experimental findings about the neurocognitive mechanisms supporting
joint action in humans. It implements the coordination of actions
and goals among the partners as a dynamic process that integrates
contextual cues, shared task knowledge and predicted outcome of
othersâ motor behavior. The control architecture is formalized by a
system of coupled dynamic neural fields representing a distributed
network of local but connected neural populations. Different pools
of neurons encode task-relevant information about action means,
task goals and context in the form of self-sustained activation pat-
terns. These patterns are triggered by input from connected populations and evolve continuously in time under the influence of
recurrent interactions. The dynamic model of joint action is evaluated in a task in which a robot and a human jointly construct a toy
object. We show that the highly context sensitive mapping from
action observation onto appropriate complementary actions allows
coping with dynamically changing joint action situations.The present research was conducted in the context of the fp6-IST2 EU-IP Project JAST (Project No. 003747) and partly financed by the FCT grants POCl/V.5/A0119/2005 and CONC-REEQ/17/2001. We would like to thank Profs. Harold Bekkering and Ruud Meulenbroek for the numerous discussions, and Emanuel Sousa, Flora Ferreira, Nzoji Hipolito, Rui Silva and Toni Machado for their help during the robotic experiments. We also thank the anonymous reviewers for their insightful comments and feedback on how to improve the manuscript
Learning a musical sequence by observation : a robotics implementation of a dynamic neural field model
We tested in a robotics experiment a dynamic neural
field model for learning a precisely timed musical sequence.
Based on neuro-plausible processing mechanisms, the model
implements the idea that order and relative timing of events
are stored in an integrated representation whereas the onset of
sequence production is controlled by a separate process. Dynamic
neural fields provide a rigorous theoretical framework to analyze
and implement the necessary neural computations that bridge
gaps between sensation and action in order to mediate working
memory, action planing, and decision making. The robot first
memorizes a short musical sequence performed by a human
teacher by watching color coded keys on a screen, and then
tries to execute the piece of music on a keyboard from memory
without any external cues. The experimental results show that
the robot is able to correct in very few demonstration-execution
cycles initial sequencing and timing errors.The work received financial support from FCT - Fundação
para a CiĂȘncia e Tecnologia within the Project Scope: PEst-
OE/EEI/UI0319/2014, the Research Centers for Mathematics
and Algoritmi through the FCT Pluriannual Funding Program,
PhD and Post-doctoral Grants (SFRH/BD/41179/2007,
SFRH/BD/48529/2008 and SFRH/BPD/71874/2010, financed
by POPH-QREN-Type 4.1-Advanced Training, co-funded by
the European Social Fund and national funds from MEC), and
Project NETT: Neural Engineering Transformative Technologies,
EU-FP7 ITN (nr.289146)
Antioxidant responses of edible and model plant species subjected to subtoxic zinc concentrations
Zinc (Zn) is a common heavy metal in polluted soils, as it is a widespread pollutant deriving both from natural sources and anthropogenic activities. The antioxidant tolerance/defence mechanisms against oxidative stress induced by subtoxic concentrations of Zn (50 and 150 ÎŒM ZnSO4) were studied in a widespread edible plant (lettuce; Lactuca sativa L.) and in an important model plant (Arabidopsis thaliana (L.) Heynh.). After 10 days (Arabidopsis) and 20 days (lettuce) of Zn exposure, Zn uptake/translocation was evaluated in both roots and shoots, while indicators of oxidative stress and stress intensity, total antioxidant capacity, and enzymatic and non-enzymatic antioxidative defence were measured in leaves. From an overall comparison of the two species, Zn root uptake in Arabidopsis subjected to 50 and 150 ÎŒM ZnSO4 was approximately 3- and 5-fold lower than in lettuce, while Zn translocation from roots to apical leaves was more efficient in Arabidopsis (23.7 vs 21.3% at 50 ÎŒM ZnSO4 and 19.3 vs 12.9% at 150 ÎŒM ZnSO4). Generally, a higher degree of Zn-induced oxidative stress (863.8 vs 21.3 ÎŒg gâ1 FW H2O2 and 1.33 vs 0.75 ÎŒMgâ1 FW MDAeq at 150 ÎŒM ZnSO4) and antioxidant response (441.2 vs 258.5mMgâ1 FW TEAC and 91.0 vs 54.9% RSA at 150 ÎŒM ZnSO4) were found in lettuce. The aim of this study is understanding (a) if subtoxic Zn levels can affect Zn uptake and translocation in the studied species and (b) if this eventual Zn absorption can influence plant oxidative status/antioxidant response. Considering that soil contamination by Zn can affect crop production and quality, the results of this research could be important for environmental, nutritional and human health issues
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