On the geometric interpretation of the Polynomial Lie Bracket for nonlinear time-delay systems

Time-delay systems are infinite dimensional, thus standard differential geometric tools can not be applied in a straightforward way. Though, thanks to a suitable extended Lie Bracket - or Polynomial Lie Bracket - which has been introduced recently, it is still possible to build up a geometric framework to tackle the analysis and synthesis problems for nonlinear time delay systems. The major contribution herein is to show that those geometric generalizations are not just formal, but are interpreted in terms of successive forward and backward flows similarly to the Lie Bracket of delay free vector fields

Observability of nonlinear time–delay systems and its application to their state realization

In this paper, it is shown that the two notions of weak observability and strong observability may not be sufficient to describe the link between the input/output equation associated to the behaviour of a system and its state space realization. A new notion, called regular observability, is introduced, which is shown to capture essential features of nonlinear time delay systems and the existence of some realization

Occurrence of HIV eradication for preexposure prophylaxis treatment with a deterministic HIV model

The authors examine the human immunodeficiency virus (HIV) eradication in this study using a mathematical model and analyse the occurrence of virus eradication during the early stage of infection. To this end they use a deterministic HIV-infection model, modify it to describe the pharmacological dynamics of antiretroviral HIV drugs, and consider the clinical experimental results of preexposure prophylaxis HIV treatment. They also use numerical simulation to model the experimental scenario, thereby supporting the clinical results with a model-based explanation. The study results indicate that the protocol employed in the experiment can eradicate HIV in infected patients at the early stage of the infection

Video guidance, landing, and imaging systems

The adaptive potential of video guidance technology for earth orbital and interplanetary missions was explored. The application of video acquisition, pointing, tracking, and navigation technology was considered to three primary missions: planetary landing, earth resources satellite, and spacecraft rendezvous and docking. It was found that an imaging system can be mechanized to provide a spacecraft or satellite with a considerable amount of adaptability with respect to its environment. It also provides a level of autonomy essential to many future missions and enhances their data gathering ability. The feasibility of an autonomous video guidance system capable of observing a planetary surface during terminal descent and selecting the most acceptable landing site was successfully demonstrated in the laboratory. The techniques developed for acquisition, pointing, and tracking show promise for recognizing and tracking coastlines, rivers, and other constituents of interest. Routines were written and checked for rendezvous, docking, and station-keeping functions

Balloon launched Viking decelerator test program

Four BLDT flights were conducted during the summer of 1972. The purpose of these tests was to qualify the Viking parachute system behind the full-scale Viking entry vehicle over the maximum range of entry conditions anticipated in the Viking '75 soft landing on Mars. A summary of the test series is presented. Test conditions ranged from a Mach number of 2.0 to 0.5 and dynamic pressure from 11.7 to 4.4 psf. This range of conditions covers the uncertainty in entry conditions at Mars due to atmospheric and entry performance uncertainties. Emphasis is placed on parachute performance and simulated Mars entry vehicle motions as influenced by the parachute performance. Conclusions are presented regarding the ability of the parachute to perform within the operational parameters required for a successful soft Martian landing. A list of references which covers all reports in the qualification test program is included

Modulation of HIV-1 replication in primary dendritic cells in contact with autologous CD4 T-lymphocytes

International audienc

P04-36. HIV-1-speficic antibody dependant cellular cytotoxicity (ADCC) médiated by primary NK cells

International audiencen.

P11-16. Transfer of HIV-1 from Langerhans and interstitial dendritic cells to T lymphocytes: protection mediated by antibodies?

International audiencen.