Servo-Stabilization of Low-Frequency Oscillations in a Liquid Bipropellant Rocket Motor

The recent work of H. S. Tsien concerning the servostabilization of rocket motors is extended to the liquid bipropellant rocket motor. It is shown that by use of a feedback system containing a device to sense the combustion chamber pressure, a suitably designed amplifier, and a servomechanism which governs the propellant How, the low-frequency oscillations which occur in the rocket configuration may be stabilized for any value of combustion time lag. A method is given for determining a transfer function of the feedback loop which will assure stable operation. The technique of the Satche diagram is employed in stability analysis

Enterotoxigenic Escherichia coli induce pro-inflammatory responses in porcine intestinal epithelial cells

F4+ enterotoxigenic Escherichia coli (ETEC) cause severe diarrhoea in both neonatal and weaning piglets, resulting in morbidity and mortality. F4 fimbriae are a key virulence factor involved in the attachment of F4+ ETEC to the intestinal epithelium. Intestinal epithelial cells (IEC) are recently being recognized as important regulators of the intestinal immune system through the secretion of cytokines, however, data on how F4+ ETEC affect this cytokine secretion are scarce. By using ETEC strains expressing either polymeric, monomeric or F4 fimbriae with a reduced polymeric stability, we demonstrated that polymeric fimbriae are essential for the adhesion of ETEC to porcine IEC as well as for the secretion of IL-6 and IL-8 by ETEC-stimulated intestinal epithelial cells. Remarkably, this cytokine secretion was not abrogated following stimulation with an F4-negative strain. As this ETEC strain expresses flagellin, TLR5 mediated signalling could be involved. Indeed, porcine IEC express TLR5 and purified flagellin induced IL-6 and IL-8 secretion, indicating that, as for other pathogens, flagellin seems to be the dominant virulence factor involved in the induction of proinflammatory responses in IEC upon ETEC infection. These results indicate a potential mucosal adjuvant capacity of ETEC-derived flagellin and may improve rational vaccine design against F4+ ETEC infections

Introduction: Professor Randall Thomas’s Depolarizing and Neutral Approach to Shareholder Rights

Like Gaul, corporate law scholarship can be divided into three overflowing buckets: pro-manager, pro-shareholder, and empirical. We classify empirical scholarship as a separate category, in significant part because of Professor Randall Thomas. In the pre-Thomas era, much of the literature fell into the first two buckets, with empirical researchers deploying data collection and analysis to support their particular bent. Then Professor Thomas emerged as a distinctive empiricist. Throughout his career, he has published scores of path breaking studies while maintaining relative neutrality as to the normative implications. He does not deploy data and its analysis to advocate for particular positions, but instead maps the terrain in which policy can then be considered. Thus, Professor Thomas’s category of scholarship is the third way—a balanced approach to generating and assessing evidence, without a particular viewpoint. We focus here on two areas of empirical exploration of the shareholder franchise, shareholder rights to sue and vote, where Professor Thomas has contributed richly and without polemics—as a neutral umpire calling balls and strikes. We show how his work has helped depolarize the division between managerialists and shareholder rights advocates

Data Note: WIA Employment Outcomes and Trends

This data note focuses on employment outcomes for individuals served by the One-Stop system through the Workforce Investment Act (WIA) Adult funding stream. Outcomes data include the rate of WIA customers entering employment and their employment retention rate. This data note compares outcomes among adults with reported disabilities to those without reported disabilities

The possibility of positive selection for both F18(+) Escherichia coli and stress resistant pigs opens new perspectives for pig breeding

International audienc