177,975 research outputs found
Editorial: The metabolic challenges of immune cells in health and disease
No full textCopyright: © 2015 Frezza and Mauro. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.CM is supported by the British Heart Foundation Fellowship FS/12/38/29640. CF is funded by the UK Medical Research Council
A virtual motorcycle driver for closed-loop simulation
No full textMULTIBODY TOOLS
FOR EVALUATING
SYSTEM
PERFORMANC
Crossovers between epigenesis and epigenetics. A multicenter approach to the history of epigenetics (1901-1975)
No full textThe origin of epigenetics has been traditionally traced back to Conrad Hal Waddington's foundational work in 1940s. The aim of the present paper is to reveal a hidden history of epigenetics, by means of a multicenter approach. Our analysis shows that genetics and embryology in early XX century--far from being non-communicating vessels--shared similar questions, as epitomized by Thomas Hunt Morgan's works. Such questions were rooted in the theory of epigenesis and set the scene for the development of epigenetics. Since the 1950s, the contribution of key scientists (Mary Lyon and Eduardo Scarano), as well as the discussions at the international conference of Gif-sur-Yvette (1957) paved the way for three fundamental shifts of focus: 1. From the whole embryo to the gene; 2. From the gene to the complex extranuclear processes of development; 3. From cytoplasmic inheritance to the epigenetics mechanisms
Aircraft maneuver regulation: a receding horizon backstepping approach
No full textCoordinated flight is a nonholonomic constraint that implies no sideslip of an aircraft. The equations of motion in coordinated flight are kinematically reducible. This property simplifies the maneuver regulation problem because under such assumption it is possible to write a lateral controller for the transverse dynamics independent of velocity. Assuming coordinated flight, the maneuver regulator consists of a model predictive controller based on the kinematic model. Since, in reality the coordinated flight assumption is seldom satisfied, the kinematic control action is back-stepped into dynamics to compute the actuation of the control surfaces. The proposed control law is tested on a multi-body SW model of an aircraft on various maneuvers, including some aggressive ones
Motion on constrained submanifolds for a kinematic control system evolving on a matrix Lie group
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Motion on submanifolds of noninvariant holonomic constraints for a kinematic control system evolving on a matrix Lie group
No full textor a control system on a matrix Lie group with one or more configuration constraints that are not left/right invariant, finding the combinations of (kinematic) control inputs satisfying the motion constraints is not a trivial problem. Two methods, one coordinate-dependent and the other coordinate-free are suggested. The first is based on the Wei-Norman formula; the second on the calculation of the annihilator of the coadjoint action of the constraint one-form at each point of the group manifold. The results are applied to a control system on SE(3) with a holonomic inertial constraint involving the noncommutative part in a nontrivial way. The difference in terms of compactness of the result between the two methods is considerable
Trajectory reconstruction by integration of GPS and a swarm of MEMS accelerometers: model and analysis of observability
No full textWe consider the problem of trajectory reconstruction for the mobile mapping system Davide. Davide is equipped with a custom GPS/INS system and a number of dead-reckoning sensors, such as odometers, inclinometers, etc. We investigate the possibility of substituting the INS with a swarm of low cost MEMS accelerometers located in various positions on board the vehicle. An observability analysis shows the feasibility of the solution and the need of integrating the distributed MEMS sensing architecture with a positioning sensor such as the GPS
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