86,889 research outputs found
Giuseppe Salvioli
No full textLa voce, pubblicata nell’ottava appendice dell’Enciclopedia italiana di scienze, lettere ed arti della Treccani, è dedicata a Giuseppe Salvioli (1857-1928), una delle figure più interessanti e complesse della cultura italiana di fine Ottocento primo Novecento. Professore di Storia del diritto italiano a Palermo e a Napoli, fu tra i più attenti osservatori della realtà economico-sociale, che egli considerò la base di partenza del suo metodo storicistico. Il primato dei fatti economici e la profondità dell’indagine storica rappresentano i punti fermi di un metodo che Salvioli andò elaborando in maniera via via più consapevole, derivandone quei motivi di ispirazione socialista, solidarista e riformista che avrebbero determinato gli indirizzi tematici della sua produzione scientifica
Jurisprudencia regional comparada de derechos humanos. El Tribunal Europeo y la Corte Interamericana
No full textStructural analysis of saposin C and B. Complete localization of disulfide bridges.
No full textSaposins A, B, C, and D are a group of homologous glycoproteins derived from a single precursor, prosaposin, and apparently involved in the stimulation of the enzymatic degradation of sphingolipids in lysosomes. All saposins have six cysteine residues at similar positions. In the present study we have investigated the disulfide structure of saposins B and C using advanced mass spectrometric procedures. Electrospray analysis showed that deglycosylated saposins B and C are mainly present as 79- and 80-residue monomeric polypeptides, respectively. Fast atom bombardment mass analysis of peptide mixtures obtained by a combination of chemical and enzymatic cleavages demonstrated that the pairings of the three disulfide bridges present in each saposin are Cys4-Cys77, Cys7-Cys71, Cys36-Cys47 for saposin B and Cys5-Cys78, Cys8-Cys72, Cys36-Cys47 for saposin C. We have recently shown that saposin C interacts with phosphatidylserine-containing vesicles inducing destabilization of the lipid surface (Vaccaro, A. M., Tatti, M., Ciaffoni, F., Salvioli, R., Serafino, A., and Barca, A. (1994) FEBS Lett. 349, 181-186); this perturbation promotes the binding of the lysosomal enzyme glucosylceramidase to the vesicles and the reconstitution of its activity. It was presently found that the effects of saposin C on phosphatidylserine liposomes and on glucosylceramidase activity are markedly reduced when the three disulfide bonds are irreversibly disrupted. These results stress the importance of the disulfide structure for the functional properties of the saposin
Globally optimal redundancy resolution with dynamic programming for robot planning: A ros implementation
No full textDynamic programming techniques have proven much more flexible than calculus of variations and other techniques in performing redundancy resolution through global optimization of performance indices. When the state and input spaces are discrete, and the time horizon is finite, they can easily accommodate generic constraints and objective functions and find Pareto-optimal sets. Several implementations have been proposed in previous works, but either they do not ensure the achievement of the globally optimal solution, or they have not been demonstrated on robots of practical relevance. In this communication, recent advances in dynamic programming redundancy resolution, so far only demonstrated on simple planar robots, are extended to be used with generic kinematic structures. This is done by expanding the Robot Operating System (ROS) and proposing a novel architecture meeting the requirements of maintainability, re-usability, modularity and flexibility that are usually required to robotic software libraries. The proposed ROS extension integrates seamlessly with the other software components of the ROS ecosystem, so as to encourage the reuse of the available visualization and analysis tools. The new architecture is demonstrated on a 7-DOF robot with a six-dimensional task, and topological analyses are carried out on both its state space and resulting joint-space solution
Globally-optimal whole body motion planning under nonholonomic constraints using dynamic programming
No full textRobotics is a key enabler for many applications in space including planetary exploration, On-Orbit Servicing (OOS), In-Space Manufacturing (ISM), Active Space Debris Removal (ADR) and deep space exploration. They are usually characterized by limited resources, which requires the robotic system to be controlled according to criteria of optimality. How to perform operations and plan the robot motion are then key factors to ensure feasibility and efficiency. This work analyzes and extends a recently proposed Dynamic Programming Optimization (DPO) algorithm for off-line motion planning in the context of planetary colonization, ranging from exploration, terrain preparation and construction. The algorithm is designed to be run on ground with the aim of (1) limiting spacecrafts cost and (2) optimally plan complex tasks with medium to long term time horizons before or during mission. The analysis is performed on a robotic system including a six degree of freedom manipulator mounted on a non-holonomic base which is exercised on tasks that leave more than one degree of redundancy. The planning tasks are resolved without decomposition, allowing the algorithm to optimize the motion of the whole kinematic structure. Redundancy is exploited to optimize the cost function of interest, while considering any constraint the robotic asset and the surrounding environment are characterized by. In our use case, the optimization is performed on a cost function associated to energy consumption, but the extreme flexibility of the algorithm leaves room for accommodation of generic requirements both in terms of functional minimization and constraints to be satisfied. A tradeoff analysis of the solution quality versus the computational resources requirements is provided. Finally, we highlight the advantages of the proposed algorithm with respect to a standard planning approach based on decomposition of the planning problem in two sub-problems: the first involving the planning of the mobile base according to some heuristics (e.g. reachability) and the second involving the planning of the manipulator
Globally-optimal whole body motion planning under nonholonomic constraints using dynamic programming
No full textRobotics is a key enabler for many applications in space including planetary exploration, On-Orbit Servicing (OOS), In-Space Manufacturing (ISM), Active Space Debris Removal (ADR) and deep space exploration. They are usually characterized by limited resources, which requires the robotic system to be controlled according to criteria of optimality. How to perform operations and plan the robot motion are then key factors to ensure feasibility and efficiency. This work analyzes and extends a recently proposed Dynamic Programming Optimization (DPO) algorithm for off-line motion planning in the context of planetary colonization, ranging from exploration to terrain preparation and construction. The algorithm is designed to be run on ground with the aim of (1) limiting spacecraft cost and (2) optimally plan complex tasks with medium to long term time horizons before or during mission. The analysis is performed on a robotic system including a six degree of freedom manipulator mounted on a nonholonomic base which is exercised on tasks that leave more than one degree of redundancy. The planning tasks are resolved without decomposition, allowing the algorithm to optimize the motion of the whole kinematic structure. Redundancy is exploited to optimize the cost function of interest, while considering any constraint the robotic asset and the surrounding environment are characterized by. In our use case, the optimization is performed on a cost function associated to energy consumption. A tradeoff analysis of the solution quality versus the computational resources requirements is provided. Finally, we highlight the advantages of the proposed algorithm with respect to a standard planning approach based on decomposition of the planning problem in two sub-problems: the first involving the planning of the mobile base according to some heuristics (e.g. reachability) and the second involving the planning of the manipulator
Optimal Whole Body Trajectory Planning for Mobile Manipulators in Planetary Exploration and Construction
No full textSpace robotics poses unique challenges arising from the limitation of energy and computational resources, and the complexity of the environment and employed platforms. At the control center, offline motion planning is fundamental in the computation of optimized trajectories accounting for the system's constraints. Smooth movements, collision and forbidden areas avoidance, target visibility and energy consumption are all important factors to consider to be able to generate feasible and optimal plans. When mobile manipulators (terrestrial, aerial) are employed, the base and the arm movements are often separately planned, ultimately resulting in suboptimal solutions. We propose an Optimal Whole Body Planner (OptiWB) based on discrete Dynamic Programming (DP) and optimal interpolation. Kinematic redundancy is exploited for collision and forbidden areas avoidance, and to improve target illumination and visibility from onboard cameras. The planner, implemented in ROS (Robot Operating System), interfaces 3DROCS, a mission planner used in several programs of the European Space Agency (ESA) to support planetary exploration surface missions and part of the ExoMars Rover's planning software. The proposed approach is exercised on a simplified version of the Analog-1 Interact rover by ESA, a 7-DOFs robotic arm mounted on a four wheels non-holonomic platform
STRUCTURAL-ANALYSIS OF SAPOSIN-C AND SAPOSIN-B - COMPLETE LOCALIZATION OF DISULFIDE BRIDGES
No full textSaposins A, B, C, and D are a group of homologous glycoproteins derived from a single precursor, prosaposin, and apparently involved in the stimulation of the enzymatic degradation of sphingolipids in lysosomes. All saposins have six cysteine residues at similar positions. In the present study we have investigated the disulfide structure of saposins B and C using advanced mass spectrometric procedures. Electrospray analysis showed that deglycosylated saposins B and C are mainly present as 79- and 80-residue monomeric polypeptides, respectively. Fast atom bombardment mass analysis of peptide mixtures obtained by a combination of chemical and enzymatic cleavages demonstrated that the pairings of the three disulfide bridges present in each saposin are Cys4-Cys77, Cys7-Cys71, Cys36-Cys47 for saposin B and Cys5-Cys78, Cys8-Cys72, Cys36-Cys47 for saposin C. We have recently shown that saposin C interacts with phosphatidylserine-containing vesicles inducing destabilization of the lipid surface (Vaccaro, A. M., Tatti, M., Ciaffoni, F., Salvioli, R., Serafino, A., and Barca, A. (1994) FEBS Lett. 349, 181-186); this perturbation promotes the binding of the lysosomal enzyme glucosylceramidase to the vesicles and the reconstitution of its activity. It was presently found that the effects of saposin C on phosphatidylserine liposomes and on glucosylceramidase activity are markedly reduced when the three disulfide bonds are irreversibly disrupted. These results stress the importance of the disulfide structure for the functional properties of the saposin
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