Global Tracking Passivity--based PI Control of Bilinear Systems and its Application to the Boost and Modular Multilevel Converters

This paper deals with the problem of trajectory tracking of a class of bilinear systems with time--varying measurable disturbance. A set of matrices {A,B_i} has been identified, via a linear matrix inequality, for which it is possible to ensure global tracking of (admissible, differentiable) trajectories with a simple linear time--varying PI controller. Instrumental to establish the result is the construction of an output signal with respect to which the incremental model is passive. The result is applied to the boost and the modular multilevel converter for which experimental results are given.Comment: 9 pages, 10 figure

Desempenho de feijão-caupi de porte ereto e semi-ereto na região Ecótono Cerrado-Pantanal.

No Estado de Mato Grosso do Sul as cultivares e linhagens de feijão-caupi apresentam ampla variabilidade o que justifica a realização de ensaios regionalizados com o intuito de se definir aquelas com maior potencial produtivo. O presente trabalho teve por objetivo avaliar o desempenho de 16 genótipos de feijão-caupi desenvolvidos pela Embrapa Meio Norte (Teresina-PI), entre linhagens avançadas e cultivares comerciais, na região ?ecótono cerrado-pantanal? do Estado de Mato Grosso do Sul. O experimento foi conduzido na área experimental da Universidade Estadual do Mato Grosso do Sul, Unidade de Aquidauana, na safra da seca do período agrícola 2010/2011.CONAC 2012. Disponível em: http://www.conac2012.org/resumos/pdf/050g.pdf. Acesso em: 03 jul. 2013

An investigation on corrosion protection layers in pipelines transporting hydrocarbons

Chemical reactions between carbon steel, water and chemical species produce corrosion layers (scales) on the internal surface of pipelines transporting hydrocarbons. Scales act as a diffusion barrier and prevent the progress of corrosion, a dangerous failure initiator. The protective film (10-100 m thickness) can be removed locally by the action of the internal flow, or by other mechanisms. Adhesion with the substrate and the failure modes of the corrosion layer can be tested by indentation. Some results are presented of experiments performed on specimens with scales grown in a controlled environment

SISTEMI DI ACCUMULO DI IDROGENO AD IDRURI DI MAGNESIO: VERIFICA SPERIMENTALE DEGLI EFFETTI DI SCALA

CESI RICERCA ha in corso un programma di ricerca per valutare le potenzialità di sistemi di accumulo di idrogenobasati su idruri di magnesio in applicazioni stazionarie. L’attività è effettuata con la collaborazione del GruppoIdrogeno dell’Università di Padova e con Venezia Tecnologie. A partire da materiali sviluppati da UNIPD e VETEC,CESI RICERCA ha progettato, realizzato e sperimentato serbatoi di accumulo di capacità diversa al fine di valutare leprestazioni del sistema in termini di capacità totale di accumulo, cinetica di absorbimento e desorbimento di idrogenoed analizzare l’eventuale degrado a valle di cicli di carica e scarica di idrogeno. In particolare, per valutare gli effettidi scala (scale-up), che sono della massima importanza in applicazioni industriali, CESI RICERCA ha progettatoe sperimentato in differenti condizioni operative un sistema di accumulo contenente 0.5 kg di idruro di magnesio.La sperimentazione sull’accumulatore ha riguardato l’attivazione delle polveri e l’esecuzione di una serie di ciclidi absorbimento e desorbimento di idrogeno; i dati sperimentali sono stati confrontati con risultati di laboratorio.L’accumulatore ha presentato una capacità massima di accumulo di idrogeno in peso del 5.35%; gli effetti di scalasono stati evidenziati da una cinetica più lenta, da sensibili effetti termici locali e da un degrado delle prestazionidopo alcuni cicli di carica e scarica di idrogeno. Al fine di identificare le cause del degrado delle prestazioni, sono stateeffettuate ulteriori attività sperimentali su accumulatori di taglia ridotta (circa 30 grammi di polvere) sviluppandoe testando nuove configurazioni degli accumulatori tali da minimizzare gli effetti negativi legati allo scale-up delsistema

Longitudinal changes in acylated versus unacylated ghrelin levels may be involved in the underlying mechanisms of the switch in nutritional phases in Prader-Willi syndrome

Introduction: Prader-Willi syndrome (PWS) is characterized by a switch from failure to thrive to excessive weight gain and hyperphagia in early childhood. An elevated, more unfavorable ratio between acylated and unacylated ghrelin (AG/UAG ratio) might play a role in the underlying mechanisms of this switch. We aimed to assess the evolution of the appetite-regulating hormones acylated ghrelin (AG) and unacylated ghrelin (UAG) and the AG/UAG ratio and their association with the change in eating behavior in children with PWS, compared to healthy age-matched controls. Methods: A longitudinal study was conducted in 134 children with PWS and 157 healthy controls, from the Netherlands, France, and Belgium. Levels of AG and UAG and the AG/UAG ratio were measured and nutritional phases as reported for PWS were scored. Results: The AG/UAG ratio was lower in the first years of life in PWS than in controls and started to increase from the age of 3 years, resulting in a high-normal AG/UAG ratio compared to controls. The AG levels remained stable during the different nutritional phases (p = 0.114), while the UAG levels decreased from 290 pg/mL in phase 1a to 137 pg/mL in phase 2b (p < 0.001). The AG/UAG ratio increased significantly from 0.81 in phase 2a to 1.24 in phase 2b (p = 0.012). Conclusions: The change from failure to thrive to excessive weight gain and hyperphagia in infants and children with PWS coincides with an increase in AG/UAG ratio. The increase in AG/UAG ratio occurred during phase 2a, thus before the onset of hyperphagia

Single-cell delineation of lineage and genetic identity in the mouse brain

During neurogenesis, mitotic progenitor cells lining the ventricles ofthe embryonic mouse brain undergo their final rounds of cell division, giving rise to a wide spectrum of postmitotic neurons and glia(1,2). The link between developmental lineage and cell-type diversity remains an open question. Here we used massively parallel tagging of progenitors to track clonal relationships and transcriptomic signatures during mouse forebrain development. We quantified clonal divergence and convergence across all major cell classes postnatally, and found diverse types of GABAergic neuron that share a common lineage. Divergence of GABAergic clones occurred during embryogenesis upon cell-cycle exit, suggesting that differentiation into subtypes is initiated as a lineage-dependent process at the progenitor cell level

LEPRA LEPROMATOSA PENEAL EN PACIENTE CON ENFERMEDAD DE CHAGAS. REPORTE DE UN CASO

Se presenta el caso de un paciente masculino de 52 años con fimosis secundaria a una masa pseudotumoral prepucial. El paciente presentaba una historia de enfermedad de Hansen con afectación de piel, laringe y bronquios. Previa a la circuncisión, el examen físico revelaba, además de las alteraciones lepromatosas, un mega esófago secundario a estenosis en la porción distal. El análisis laboratorial mediante la técnica de ELISA dio positivo para Trypanosoma cruzi, patógeno responsable de la enfermedad de Chagas. Sólo pudimos encontrar un caso previo reportado de lepra lepromatosa con afectación prepucial. La coexistencia de lepra y miocardiopatía chagásica es inusual pero bien conocida por casos reportados en Brasil e India. Sin embargo, de acuerdo a nuestros conocimientos, éste es el primer caso reportado de una sociación entre lepra lepromatosa y mega esófago chagásico en un paciente con fimosis

Peritoneal changes due to laparoscopic surgery

Item does not contain fulltextBACKGROUND: Laparoscopic surgery has been incorporated into common surgical practice. The peritoneum is an organ with various biologic functions that may be affected in different ways by laparoscopic and open techniques. Clinically, these alterations may be important in issues such as peritoneal metastasis and adhesion formation. METHODS: A literature search using the Pubmed and Cochrane databases identified articles focusing on the key issues of laparoscopy, peritoneum, inflammation, morphology, immunology, and fibrinolysis. Results : Laparoscopic surgery induces alterations in the peritoneal integrity and causes local acidosis, probably due to peritoneal hypoxia. The local immune system and inflammation are modulated by a pneumoperitoneum. Additionally, the peritoneal plasmin system is inhibited, leading to peritoneal hypofibrinolysis. CONCLUSION: Similar to open surgery, laparoscopic surgery affects both the integrity and biology of the peritoneum. These observations may have implications for various clinical conditions.1 januari 201

Elevated ratio of acylated to unacylated ghrelin in children and young adults with Prader–Willi syndrome

Prader–Willi syndrome (PWS) is characterized by a switch from failure to thrive to excessive weight gain and hyperphagia in early childhood. Hyperghrelinemia may be involved in the underlying mechanisms of the switch. The purpose of this study is to evaluate acylated ghrelin (AG) and unacylated ghrelin (UAG) levels in PWS and investigate their associations with hyperphagia. This is a cross-sectional clinical study conducted in three PWS expert centers in the Netherlands and France. Levels of AG and UAG and the AG/UAG ratio were determined in 138 patients with PWS (0.2–29.4 years) and compared with 50 age-matched obese subjects (4.3–16.9 years) and 39 healthy controls (0.8–28.6 years). AEBSF was used to inhibit deacylation of AG. As a group, PWS patients had higher AG but similar UAG levels as healthy controls (AG 129.1 vs 82.4 pg/ml, p = 0.016; UAG 135.3 vs 157.3 pg/ml, resp.), resulting in a significantly higher AG/UAG ratio (1.00 vs 0.61, p = 0.001, resp.). Obese subjects had significantly lower AG and UAG levels than PWS and controls (40.3 and 35.3 pg/ml, resp.), but also a high AG/UAG ratio (1.16). The reason for the higher AG/UAG ratio in PWS and obese was, however, completely different, as PWS had a high AG and obese a very low UAG. PWS patients without weight gain or hyperphagia had a similar AG/UAG ratio as age-matched controls, in contrast to those with weight gain and/or hyperphagia who had an elevated AG/UAG ratio. The switch to excessive weight gain in PWS seems to coincide with an increase in the AG/UAG ratio, even prior to the start of hyperphagia