Kineto-dynamic modeling of human upper limb for robotic manipulators and assistive applications

The sensory-motor architecture of human upper limb and hand is characterized by a complex inter-relation of multiple elements, such as ligaments, muscles, and joints. Nonetheless, humans are able to generate coordinated and meaningful motor actions to interact-and eventually explore-the external environment. Such a complexity reduction is usually studied within the framework of synergistic control, whose focus has been mostly limited on human grasping and manipulation. Little attention has been devoted to the spatio-temporal characterization of human upper limb kinematic strategies and how the purposeful exploitation of the environmental constraints shapes human execution of manipulative actions. In this chapter, we report results on the evidence of a synergistic control of human upper limb and during manipulation with the environment. We propose functional analysis to characterize main spatio-temporal coordinated patterns of arm joints. Furthermore, we study how the environment influences human grasping synergies. The effect of cutaneous impairment is also evaluated. Applications to the design and control of robotic and assistive devices are finally discussed

A technical framework for human-like motion generation with autonomous anthropomorphic redundant manipulators

The need for users' safety and technology accept-ability has incredibly increased with the deployment of co-bots physically interacting with humans in industrial settings, and for people assistance. A well-studied approach to meet these requirements is to ensure human-like robot motions. Classic solutions for anthropomorphic movement generation usually rely on optimization procedures, which build upon hypotheses devised from neuroscientific literature, or capitalize on learning methods. However, these approaches come with limitations, e.g. limited motion variability or the need for high dimensional datasets. In this work, we present a technique to directly embed human upper limb principal motion modes computed through functional analysis in the robot trajectory optimization. We report on the implementation with manipulators with redundant anthropomorphic kinematic architectures - although dissimilar with respect to the human model used for functional mode extraction - via Cartesian impedance control. In our experiments, we show how human trajectories mapped onto a robotic manipulator still exhibit the main characteristics of human-likeness, e.g. low jerk values. We discuss the results with respect to the state of the art, and their implications for advanced human-robot interaction in industrial co-botics and for human assistance

Discovery of a Hard X-Ray Source, SAX J0635+0533, in the Error Box of the Gamma-Ray Source 2EG 0635+0521

We have discovered an x-ray source, SAX J0635+0533, with a hard spectrum within the error box of the GeV gamma-ray source in Monoceros, 2EG J0635+0521. The unabsorbed x-ray flux is 1.2*10^-11 erg cm^-2 s^-1 in the 2-10 keV band. The x-ray spectrum is consistent with a simple powerlaw model with absorption. The photon index is 1.50 +/- 0.08 and we detect emission out to 40 keV. Optical observations identify a counterpart with a V-magnitude of 12.8. The counterpart has broad emission lines and the colors of an early B type star. If the identification of the x-ray/optical source with the gamma-ray source is correct, then the source would be a gamma-ray emitting x-ray binary.Comment: Accepted to the Astrophysical Journal, 8 page

Robotic Monitoring of Habitats: the Natural Intelligence Approach

In this paper, we first discuss the challenges related to habitat monitoring and review possible robotic solutions. Then, we propose a framework to perform terrestrial habitat monitoring exploiting the mobility of legged robotic systems. The idea is to provide the robot with the Natural Intelligence introduced as the combination of the environment in which it moves, the intelligence embedded in the design of its body, and the algorithms composing its mind. This approach aims to solve the challenges of deploying robots in real natural environments, such as irregular and rough terrains, long-lasting operations, and unexpected collisions, with the final objective of assisting humans in assessing the habitat conservation status. Finally, we present examples of robotic monitoring of habitats in four different environments: forests, grasslands, dunes, and screes

Analysis of agronomic and chemical-nutritional variability of fruits in Amazon germplasm of Capsicum chinense

Fruits of Capsicum chinense, a native species of Amazon Basin, express high levels of bioactive components such as vitamin C and carotenoids; some of them with pronounced pro-vitamin A activity such as β-carotene, which confers high economic potential to this species. The characterization of C. chinense germplasm helps in its management and conservation. Therefore, this practice is considered crucial for the identification of genotypes with superior characteristics, especially in relation to agronomic aspects and chemical-nutritional characteristics of fruits. This study aimed to characterize 55 C. chinense accessions collected from the Brazilian Amazon in terms of their agronomic and chemical-nutritional descriptors aiming to identify superior genotypes for these traits. The characterization was performed in a completely randomized design with 5 replications in non-heated environment. There was significant difference for all descriptors, confirming the variability among accessions. High heritability estimates for descriptors, such as fruit yield (95.1%) and vitamin C content of fruit (92.4%), was found to be associated with high CVg/CVe ratios of these traits, indicating a favorable condition for the selection of superior genotypes for these characteristics. A considerable part of the accessions expressed averages higher than the checks, notably for the fruit yield and the content of vitamin C. The cluster analysis resulted in the formation of 11 groups, corroborating the high variability of accessions for the agronomic and chemical-nutritional aspects of fruits. The evaluated C. chinense germplasm thus expressed high fruit yield and vitamin C content in the fruits, which makes it a promising source for the selection of superior genotypes

mGlu2 metabotropic glutamate receptors restrain inflammatory pain and mediate the analgesic activity of dual mGlu2/mGlu3 receptor agonists

Group II metabotropic glutamate receptors (mGluRs) couple to the inhibitory G-protein Gi. The group II mGluRs include two subtypes, mGlu2 and mGlu3, and their pharmacological activation produces analgesic effects in inflammatory and neuropathic pain states. However, the specific contribution of each one of the two subtypes has not been clarified due to the lack of selective orthosteric ligands that can discriminate between mGlu2 and mGlu3 subtypes

Processing of Retinal Signals in Normal and HCN Deficient Mice

This study investigates the role of two different HCN channel isoforms in the light response of the outer retina. Taking advantage of HCN-deficient mice models and of in vitro (patch-clamp) and in vivo (ERG) recordings of retinal activity we show that HCN1 and HCN2 channels are expressed at distinct retinal sites and serve different functions. Specifically, HCN1 operate mainly at the level of the photoreceptor inner segment from where, together with other voltage sensitive channels, they control the time course of the response to bright light. Conversely, HCN2 channels are mainly expressed on the dendrites of bipolar cells and affect the response to dim lights. Single cell recordings in HCN1−/− mice or during a pharmacological blockade of Ih show that, contrary to previous reports, Ikx alone is able to generate the fast initial transient in the rod bright flash response. Here we demonstrate that the relative contribution of Ih and Ikx to the rods' temporal tuning depends on the membrane potential. This is the first instance in which the light response of normal and HCN1- or HCN2-deficient mice is analyzed in single cells in retinal slice preparations and in integrated full field ERG responses from intact animals. This comparison reveals a high degree of correlation between single cell current clamp data and ERG measurements. A novel picture emerges showing that the temporal profile of the visual response to dim and bright luminance changes is separately determined by the coordinated gating of distinct voltage dependent conductances in photoreceptors and bipolar cells

High-Pass Filtering of Input Signals by the Ih Current in a Non-Spiking Neuron, the Retinal Rod Bipolar Cell

Hyperpolarization–activated cyclic nucleotide–sensitive (HCN) channels mediate the If current in heart and Ih throughout the nervous system. In spiking neurons Ih participates primarily in different forms of rhythmic activity. Little is known, however, about its role in neurons operating with graded potentials as in the retina, where all four channel isoforms are expressed. Intriguing evidence for an involvement of Ih in early visual processing are the side effects reported, in dim light or darkness, by cardiac patients treated with HCN inhibitors. Moreover, electroretinographic recordings indicate that these drugs affect temporal processing in the outer retina. Here we analyzed the functional role of HCN channels in rod bipolar cells (RBCs) of the mouse. Perforated–patch recordings in the dark–adapted slice found that RBCs exhibit Ih, and that this is sensitive to the specific blocker ZD7288. RBC input impedance, explored by sinusoidal frequency–modulated current stimuli (0.1–30 Hz), displays band–pass behavior in the range of Ih activation. Theoretical modeling and pharmacological blockade demonstrate that high–pass filtering of input signals by Ih, in combination with low–pass filtering by passive properties, fully accounts for this frequency–tuning. Correcting for the depolarization introduced by shunting through the pipette–membrane seal, leads to predict that in darkness Ih is tonically active in RBCs and quickens their responses to dim light stimuli. Immunohistochemistry targeting candidate subunit isoforms HCN1–2, in combination with markers of RBCs (PKC) and rod–RBC synaptic contacts (bassoon, mGluR6, Kv1.3), suggests that RBCs express HCN2 on the tip of their dendrites. The functional properties conferred by Ih onto RBCs may contribute to shape the retina's light response and explain the visual side effects of HCN inhibitors

Cosmic ray oriented performance studies for the JEM-EUSO first level trigger

JEM-EUSO is a space mission designed to investigate Ultra-High Energy Cosmic Rays and Neutrinos (E > 5 ⋅ 1019 eV) from the International Space Station (ISS). Looking down from above its wide angle telescope is able to observe their air showers and collect such data from a very wide area. Highly specific trigger algorithms are needed to drastically reduce the data load in the presence of both atmospheric and human activity related background light, yet retain the rare cosmic ray events recorded in the telescope. We report the performance in offline testing of the first level trigger algorithm on data from JEM-EUSO prototypes and laboratory measurements observing different light sources: data taken during a high altitude balloon flight over Canada, laser pulses observed from the ground traversing the real atmosphere, and model landscapes reproducing realistic aspect ratios and light conditions as would be seen from the ISS itself. The first level trigger logic successfully kept the trigger rate within the permissible bounds when challenged with artificially produced as well as naturally encountered night sky background fluctuations and while retaining events with general air-shower characteristics