Managing Insect and Mite Pests of Texas Corn.

20 p

Direct data-driven state-feedback control of general nonlinear systems

Through the use of the Fundamental Lemma for linear systems, a direct data-driven state-feedback control synthesis method is presented for a rather general class of nonlinear (NL) systems. The core idea is to develop a data-driven representation of the so-called velocity-form, i.e., the time-difference dynamics, of the NL system, which is shown to admit a direct linear parameter-varying (LPV) representation. By applying the LPV extension of the Fundamental Lemma in this velocity domain, a state-feedback controller is directly synthesized to provide asymptotic stability and dissipativity of the velocity-form. By using realization theory, the synthesized controller is realized as a NL state-feedback law for the original unknown NL system with guarantees of universal shifted stability and dissipativity, i.e., stability and dissipativity w.r.t. any (forced) equilibrium point, of the closed-loop behavior. This is achieved by the use of a single sequence of data from the system and a predefined basis function set to span the scheduling map. The applicability of the results is demonstrated on a simulation example of an unbalanced disc

Direct data-driven state-feedback control of general nonlinear systems

Through the use of the Fundamental Lemma for linear systems, a direct data-driven state-feedback control synthesis method is presented for a rather general class of nonlinear (NL) systems. The core idea is to develop a data-driven representation of the so-called velocity-form, i.e., the time-difference dynamics, of the NL system, which is shown to admit a direct linear parameter-varying (LPV) representation. By applying the LPV extension of the Fundamental Lemma in this velocity domain, a state-feedback controller is directly synthesized to provide asymptotic stability and dissipativity of the velocity-form. By using realization theory, the synthesized controller is realized as a NL state-feedback law for the original unknown NL system with guarantees of universal shifted stability and dissipativity, i.e., stability and dissipativity w.r.t. any (forced) equilibrium point, of the closed-loop behavior. This is achieved by the use of a single sequence of data from the system and a predefined basis function set to span the scheduling map. The applicability of the results is demonstrated on a simulation example of an unbalanced disc

Convex Incremental Dissipativity Analysis of Nonlinear Systems

Efficiently computable stability and performance analysis of nonlinear systems becomes increasingly more important in practical applications. An important notion connecting stability and performance is dissipativity. However, this property is usually only valid around an equilibrium point of the nonlinear system and usually involves cumbersome computations to find a valid storage function. Analyzing stability using the trajectories of the nonlinear system, i.e. incremental stability analysis, has shown to solve the first issue. However, how stability and performance characterizations of nonlinear systems in the incremental framework are linked to dissipativity, and how general performance characterization beyond the $\mathcal{L}_2$-gain concept can be understood in the incremental framework is largely unknown. By systematically establishing the missing links, this paper presents a matrix inequality based convex dissipativity analysis with the use of quadratic storage and supply functions, for a rather general class of systems with smooth nonlinearities. The proposed dissipativity analysis links the notions of differential, incremental and general dissipativity by a chain of implications. We show that through differential dissipativity, we give guarantees on incremental and general dissipativity of the nonlinear system. Using the results from the aforementioned chain of implications, incremental extensions for the analysis of $\mathcal{L}_2$-gain, the generalized $\mathcal{H}_2$-norm, $\mathcal{L}_\infty$-gain and passivity of a nonlinear system are presented. Moreover, we give a convex computation method to solve the obtained conditions. The effectiveness of the analysis tools are demonstrated by means of an academic example

Hypoxanthine production by ischemic heart demonstrated by high pressure liquid chromatography of blood purine nucleosides and oxypurines

An isocratic high pressure liquid chromatographic system was developed for the estimation of purine nucleosides and oxypurines in blood. Use was made of a reversed-phase column. Nucleotides derived from erythrocytes affected the separation; these compounds were removed with A12O3. The recovery of the whole clean-up procedure exceeded 75%, and the lower detection limit of the assay for blood metabolites was 0.1 mumol/l. In 6 healthy volunteers, non-resting, the following blood concentrations (mean values +/- S.D. in mumol/l) were observed: adenosine (less than 0.1), inosine (0.2 +/- 0.1), hypoxanthine (2.2 +/- 1.3) and xanthine (0.2 +/- 0.1). In plasma and serum the total amount of these compounds was 1.9 and 5.4 times higher, respectively, presumably due to nucleotide breakdown during blood processing. The myocardial arterial-venous differences of blood purine nucleosides, oxypurines and lactate were subsequently measured in blood samples from 13 patients with angiographically documented ischemic heart disease, undergoing an atrial pacing stress test. No significant release of adenosine, inosine and xanthine by the heart was detectable in this stu

Ho Chi Minh Ville : de la migration à l'emploi

L'agglomération de Ho Chi Minh Ville est le principal pôle de développement du Viêtnam. La politique de libéralisation économique mise en oeuvre depuis 1986 est en train de bouleverser l'économie de la ville, ce qui entraîne notamment une forte croissance économique, un accroissement des disparités ville-campagne, une augmentation des flux migratoires, un développement du secteur privé, un élargissement des disparités sociales en ville. Parallèlement, le contrôle de l'immigration en ville, depuis longtemps strict, avec l'instauration d'un permis de résidence, est devenu beaucoup plus lâche. Dans ce contexte, les principales caractéristiques de la migration et de l'emploi en ville sont analysées à partir des résultats d'une enquête menée en 1994. Certaines données sont semblables à ce que l'on rencontre dans d'autres pays de l'Asie du Sud-Est, telle que la prépondérance des femmes parmi les migrants. D'autres résultats sont plus originaux, comme l'éducation assez élevée du migrant, le maintien du chômage à un niveau inférieur à ce qu'on aurait pu craindre, l'insertion limitée du migrant dans le secteur informel, le revenu relativement élevé du migrant... Cependant, l'évolution en cours laisse présager une modification très rapide de la situation avec une très forte croissance urbaine à venir, même si les données démographiques récentes manquent cruellement, le dernier recensement datant de 1989. Cette urbanisation sera très difficile à maîtriser et ses conséquences risquent d'être négatives à terme. Une des solutions serait le développement des centres urbains secondaires destinés à faire "tampon" sur les axes de migration de la campagne vers la grande ville. (Résumé d'auteur

Myocardial malondialdehyde and uric acid release after short-lasting coronary occlusion during coronary angioplasty: potential mechanisms for free radical generation

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Urate production by human heart

Xanthine oxidoreductase has been demonstrated in the heart of various species. However, its presence in human heart is still debated. In the literature, high to undetectable levels have been reported. We studied the arterial-venous urate difference across the heart of patients undergoing both routine cardiac catheterization and percutaneous transluminal coronary angioplasty. Urate is the end product of the reaction catalysed by xanthine oxidoreductase. In 10 patients, studied before angioplasty, the plasma urate level in the great cardiac vein exceeded the arterial one by 26 +/- 10 nmol/ml (P = 0.028). In a further 13 patients, urate production was maximal immediately after the last of four consecutive occlusions (23 +/- 8 nmol/ml, P = 0.018) and concomitant with increased coronary sinus hypoxanthine levels. We conclude that xanthine oxidoreductase is probably present in the heart of patients, suffering from ischemic heart disease, and responsible for the increase in urate production during transient myocardial ischemia

Toward a Rapid Production of Multivirus-Specific T Cells Targeting BKV, Adenovirus, CMV, and EBV from Umbilical Cord Blood

Umbilical cord blood (CB) has emerged as an effective alternative donor source for hematopoietic stem cell transplantation. Despite this success, the prolonged duration of immune suppression following CB transplantation and the naiveté of CB T cells leave patients susceptible to viral infections. Adoptive transfer of ex vivo-expanded virus-specific T cells from CB is both feasible and safe. However, the manufacturing process of these cells is complicated, lengthy, and labor-intensive. We have now developed a simplified method to manufacture a single culture of polyclonal multivirus-specific cytotoxic T cells in less than 30 days. It eliminates the need for a live virus or transduction with a viral vector, thus making this approach widely available and GMP-applicable to target multiple viruses. The use of overlapping PepMixes as a source of antigen stimulation enable expansion of the repertoire of the T cell product to any virus of interest and make it available as a third party “off the shelf” treatment for viral infections following transplantation