Human-robot collaboration for safe object transportation using force feedback

[EN] This work presents an approach based on multi-task, non-conventional sliding mode control and admittance control for human-robot collaboration aimed at handling applications using force feedback. The proposed robot controller is based on three tasks with different priority levels in order to cooperatively perform the safe transportation of an object with a human operator. In particular, a high-priority task is developed using non-conventional sliding mode control to guarantee safe reference parameters imposed by the task, e.g., keeping a load at a desired orientation (to prevent spill out in the case of liquids, or to reduce undue stresses that may compromise fragile items). Moreover, a second task based on a hybrid admittance control algorithm is used for the human operator to guide the robot by means of a force sensor located at the robot tool. Finally, a third low-priority task is considered for redundant robots in order to use the remaining degrees of freedom of the robot to achieve a pre-set secondary goal (e.g., singularity avoidance, remaining close to a homing configuration for increased safety, etc.) by means of the gradient projection method. The main advantages of the proposed method are robustness and low computational cost. The applicability and effectiveness of the proposed approach are substantiated by experimental results using a redundant 7R manipulator: the Sawyer collaborative robot. (C) 2018 Elsevier B.V. All rights reserved.This work was supported in part by the Spanish Government under Project DPI2017-87656-C2-1-R, and the Generalitat Valenciana under Grants VALi+d APOSTD/2016/044 and BEST/2017/029.Solanes Galbis, JE.; Gracia Calandin, LI.; Muñoz-Benavent, P.; Valls Miro, J.; Carmichael, MG.; Tornero Montserrat, J. (2018). Human-robot collaboration for safe object transportation using force feedback. Robotics and Autonomous Systems. 107:196-208. https://doi.org/10.1016/j.robot.2018.06.003S19620810

Molecular solids of actinide hexacyanoferrate: Structure and bonding

The hexacyanometallate family is well known in transition metal chemistry because the remarkable electronic delocalization along the metal-cyano-metal bond can be tuned in order to design systems that undergo a reversible and controlled change of their physical properties. We have been working for few years on the description of the molecular and electronic structure of materials formed with [Fe(CN)6]n- building blocks and actinide ions (An = Th, U, Np, Pu, Am) and have compared these new materials to those obtained with lanthanide cations at oxidation state +III. In order to evaluate the influence of the actinide coordination polyhedron on the three- dimensional molecular structure, both atomic number and formal oxidation state have been varied : oxidation states +III, +IV. EXAFS at both iron K edge and actinide LIII edge is the dedicated structural probe to obtain structural information on these systems. Data at both edges have been combined to obtain a three-dimensional model. In addition, qualitative electronic information has been gathered with two spectroscopic tools : UV-Near IR spectrophotometry and low energy XANES data that can probe each atom of the structural unit : Fe, C, N and An. Coupling these spectroscopic tools to theoretical calculations will lead in the future to a better description of bonding in these molecular solids. Of primary interest is the actinide cation ability to form ionic – covalent bonding as 5f orbitals are being filled by modification of oxidation state and/or atomic number

Detection of Helicobacter pylori Microevolution and Multiple Infection from Gastric Biopsies by Housekeeping Gene Amplicon Sequencing

Despite the great efforts devoted to research on Helicobacter pylori, the prevalence of single-strain infection or H. pylori mixed infection and its implications in the mode of transmission of this bacterium are still controversial. In this study, we explored the usefulness of housekeeping gene amplicon sequencing in the detection of H. pylori microevolution and multiple infections. DNA was extracted from five gastric biopsies from four patients infected with distinct histopathological diagnoses. PCR amplification of six H. pylori-specific housekeeping genes was then assessed on each sample. Optimal results were obtained for the cgt and luxS genes, which were selected for amplicon sequencing. A total of 11,833 cgt and 403 luxS amplicon sequences were obtained, 2042 and 112 of which were unique sequences, respectively. All cgt and luxS sequences were clustered at 97% to 9 and 13 operational taxonomic units (OTUs), respectively. For each sample from a different patient, a single OTU comprised the majority of sequences in both genes, but more than one OTU was detected in all samples. These results suggest that multiple infections with a predominant strain together with other minority strains are the main way by which H. pylori colonizes the human stomach

Combined surgical approach for sarcoma lung metastasis with atrial involvement

A 20-year-old patient, who had been treated for a femur sarcoma with pulmonary metastases 8 years before, arrived at our institution with a new metastatic hilar lung nodule. During the standard lobectomy procedure an unexpected atrial invasion by the tumor was discovered. Intraoperative transesophageal echocardiography (TEE) showed a big pediculated tumor in the atrium. Cardiopulmonary bypass (CPB) was required in order to safely resect the atrial wall with the tumor. The atrial defect was repaired with a pericardial patch. Postoperative course was uneventful. After 14 months, the patient is asymptomatic and free of disease

Tear fluid biomarkers in ocular and systemic disease: potential use for predictive, preventive and personalised medicine

In the field of predictive, preventive and personalised medicine, researchers are keen to identify novel and reliable ways to predict and diagnose disease, as well as to monitor patient response to therapeutic agents. In the last decade alone, the sensitivity of profiling technologies has undergone huge improvements in detection sensitivity, thus allowing quantification of minute samples, for example body fluids that were previously difficult to assay. As a consequence, there has been a huge increase in tear fluid investigation, predominantly in the field of ocular surface disease. As tears are a more accessible and less complex body fluid (than serum or plasma) and sampling is much less invasive, research is starting to focus on how disease processes affect the proteomic, lipidomic and metabolomic composition of the tear film. By determining compositional changes to tear profiles, crucial pathways in disease progression may be identified, allowing for more predictive and personalised therapy of the individual. This article will provide an overview of the various putative tear fluid biomarkers that have been identified to date, ranging from ocular surface disease and retinopathies to cancer and multiple sclerosis. Putative tear fluid biomarkers of ocular disorders, as well as the more recent field of systemic disease biomarkers, will be shown

TBK1: a potential therapeutic target in RA

This is a pre-copy-editing, author-produced PDF of an article accepted for publication in Rheumatology following peer review. The definitive publisher-authenticated version Rheumatology, 51 (4), art. no. ker207, pp. 588-589. is available online at: http://dx.doi.org/10.1093/rheumatology/ker207

Complex Evolutionary History of the Aeromonas veronii Group Revealed by Host Interaction and DNA Sequence Data

Aeromonas veronii biovar sobria, Aeromonas veronii biovar veronii, and Aeromonas allosaccharophila are a closely related group of organisms, the Aeromonas veronii Group, that inhabit a wide range of host animals as a symbiont or pathogen. In this study, the ability of various strains to colonize the medicinal leech as a model for beneficial symbiosis and to kill wax worm larvae as a model for virulence was determined. Isolates cultured from the leech out-competed other strains in the leech model, while most strains were virulent in the wax worms. Three housekeeping genes, recA, dnaJ and gyrB, the gene encoding chitinase, chiA, and four loci associated with the type three secretion system, ascV, ascFG, aexT, and aexU were sequenced. The phylogenetic reconstruction failed to produce one consensus tree that was compatible with most of the individual genes. The Approximately Unbiased test and the Genetic Algorithm for Recombination Detection both provided further support for differing evolutionary histories among this group of genes. Two contrasting tests detected recombination within aexU, ascFG, ascV, dnaJ, and gyrB but not in aexT or chiA. Quartet decomposition analysis indicated a complex recent evolutionary history for these strains with a high frequency of horizontal gene transfer between several but not among all strains. In this study we demonstrate that at least for some strains, horizontal gene transfer occurs at a sufficient frequency to blur the signal from vertically inherited genes, despite strains being adapted to distinct niches. Simply increasing the number of genes included in the analysis is unlikely to overcome this challenge in organisms that occupy multiple niches and can exchange DNA between strains specialized to different niches. Instead, the detection of genes critical in the adaptation to specific niches may help to reveal the physiological specialization of these strains

Financial sector development and economic growth: evidence from Cameroon

For decades, African economies have embarked on financial sector reforms. However, the empirical implications of these reforms have been divergent. This paper investigates the impact of financial development on Economic growth using time series data in Cameroon. This investigation was carried out using three common indicators of financial development (broad money, deposit/GDP and domestic credit to private sector). Using the Auto Regressive Distributive Lag (ARDL) technique of estimation, it was discovered that there exist a short-run positive relationship between monetary mass (M2), government expenditure and economic growth, a short run negative relationship between bank deposits, private investment and economic growth equally exists. However in the long run, all indicators of financial development show a positive and significant impact on economic growth. This paper thus confirms the existence of a positive and long-term impact of all the indicators of financial development on economic growth through bound test. It is therefore proposed that the financial reforms in Cameroon should be pushed forward in order to boost the development of the financial sector thus an increase in its role on economic growth

A Money Multiplier Model for a Developing Economy: The Venezuelan Case (Un modèle du multiplicateur monétaire appliqué à une économie en voie de développement: le cas du Venezuela) (Un modelo del multiplicador monetario para una economía en vías de desarrollo: El caso de Venezuela)

This paper analyzes the determinants of the money multiplier in an open developing economy with a fixed exchange rate, using that of Venezuela as an illustration. The openness of the Venezuelan economy, in which investment activity can be financed either by domestic or by foreign borrowing without much impediment, implies that the foreign interest rate is the main relevant opportunity cost of holding domestic financial assets--rather than the domestic interest rate, because sufficient domestic money market instruments have not been developed. An annual model of the money multiplier is estimated for the sample periods 1950-70 (Model A) and 1950-72 (Model B). Model A is used to test the forecasting performance outside the sample period for the years 1971 and 1972. It is shown that the forecast for the excess reserves ratio is well on track, with only a slight underestimation in 1972, while underestimation of the currency-deposit ratio is somewhat more serious (with the result that the money multiplier is overestimated in 1971 and 1972 but is well within the error of estimate of the model). A simple simulation for the years 1971 and 1972 concerning the effect on the money multiplier of a change in the required reserve ratio is also performed. As expected, this shows that an increase in the required reserve ratio reduces the value of the multiplier in both years. /// La présente étude est consacrée à l'analyse des déterminants du multiplicateur monétaire dans une économie en développement qui est ouverte et utilise une monnaie dont le taux de change est fixe; l'exemple retenu est celui du Venezuela. L'ouverture de l'économie vénézuélienne, dont les opérations d'investissement peuvent être financées presque aussi librement au moyen d'emprunts à l'étranger qu'à l'aide de ressources locales, implique que le coût d'option relatif à la détention d'actifs financiers intérieurs est le taux d'intérêt en vigueur à l'étranger -- au lieu du taux d'intérêt local qu'un marché monétaire trop peu développé ne permet pas d'établir facilement. Un modèle du multiplicateur monétaire est estimé à partir de données annuelles relatives à deux périodes: 1950-70 (Modèle A) et 1950-72 (Modèle B). Les prévisions établies à l'aide du Modèle A pour les années 1971 et 1972 sont ensuite utilisées pour vérifier la valeur du modèle comme instrument de prévision en dehors de la période servant d'échantillon. Il ressort qu'abstraction faite d'une très légère différence en moins du chiffre prévu pour 1972, les prévisions relatives au rapport entre les réserves excédentaires et les dépôts sont généralement conformes aux résultats effectifs; en revanche, le modèle sous-estime dans des proportions plus inquiétantes le rapport entre la monnaie en circulation et les dépôts (il en résulte que le multiplicateur monétaire est surestimé en 1971 et en 1972, sans aller pour autant audelà de la marge d'erreur prévue pour le modèle). L'analyse comporte également une simulation simple de l'incidence d'une modification du coefficient de réserves obligatoires sur le multiplicateur monétaire pour les années 1971 et 1972. Comme prévu, cette opération fait ressortir qu'un relèvement du coefficient de réserves obligatoires réduit la valeur du multiplicateur monétaire dans chacune des deux années. /// Se analizan en este artículo los determinantes del multiplicador monetario en una economía en vías de desarrollo, abierta al exterior y con un tipo de cambio fijo, tomándose como ejemplo el caso de Venezuela. La apertura al exterior de una economía como la venezolana, donde la inversión puede financiarse con préstamos internos o externos sin gran obstáculo, implica que el principal costo de oportunidad de mantener activos financieros nacionales es el tipo de interés extranjero, no el interno, porque no se han desarrollado suficientemente los instrumentos del mercado monetario nacional. Se estima un modelo anual del multiplicador monetario para los períodos muestrales 1950-70 (Modelo A) y 1950-72 (Modelo B). El Modelo A se utiliza para verificar la eficiencia predictiva fuera del período muestral en los años 1971 y 1972. Los resultados indican que la predicción de la razón del exceso de reservas es bastante precisa, con una pequeña subestimación en 1972, mientras que la subestimación de la razón caja-depósitos es algo más grave (resultando en una sobrestimación del multiplicador monetario en 1971 y 1972 que, sin embargo, cae dentro del error de estimación del modelo). También se efectúa una simulación simple del efecto de una modificación del coeficiente de reserva obligatoria sobre el multiplicador monetario en los años 1971 y 1972. Como podría esperarse, los resultados indican que un incremento del coeficiente de reserva obligatoria reduce el valor del multiplicador en ambos años.