The gene cluster gspCDEFGHIJKLM codes for various structural components of the type II secretion pathway which is responsible for the secretion of heat-labile enterotoxin by enterotoxigenic Escherichia coli (ETEC). In this work, we used a variety of molecular approaches to elucidate the transcriptional organization of the ETEC type II secretion system and to unravel the mechanisms by which the ...

Cyber-Physical Systems (CPSs) are getting increasingly complex and interconnected. Consequently, their inherent safety risks security so intertwined that the conventional analysis approaches which address them separately may be rendered inadequate. STPA (Systems-Theoretic Process Analysis) is a top-down hazard technique has been incorporated into several recently proposed integrated Safety Secu...

Traditional hazard analysis techniques are grounded in reliability theory and analyze the human controller-if at all-in terms of estimated or calculated probabilities of failure. Characterizing sub-optimal human performance as "human error" offers limited explanation for accidents and is inadequate in improving the safety of human control in complex, automated systems such as today's aerospace ...

Traditional approaches to hazard analysis and safety-related risk management are based on an accident model that focuses on failure events in static engineering designs and linear notions of causality. They are therefore limited in their ability to include complex human decision-making, software errors, system accidents (versus component failure accidents), and organizational risk factors in th...

The genome DNA of Escherichia coli is associated with about 10 DNA-binding structural proteins, altogether forming the nucleoid. The nucleoid proteins play some functional roles, besides their structural roles, in the global regulation of such essential DNA functions as replication, recombination, and transcription. Using a quantitative Western blot method, we have performed for the first time ...

Agile development methodologies are becoming a tendency in today’s changing software development. However, due to a lack of safety assurance activities, especially safety analysis, agile methods are criticized for being inadequate for the development of safe software. In this paper, we introduce an agile ”Safe Scrum” by mapping a novel systematic safety analysis method, called STPA (System-Theo...

We report that the H-NS nucleoid protein plays a positive role in the expression of stringently regulated genes in Escherichia coli. Bacteria lacking both H-NS and the paralog StpA show reduced growth rate. Colonies displaying an increased growth rate were isolated, and mapping of a suppressor mutation revealed a base pair substitution in the spoT gene. The spoT(A404E) mutant showed low ppGpp s...

Human and non-human primates are able to perceive three-dimensional structure from motion displays. Three-dimensional structure-from-motion (object-motion) displays were used to test the hypothesis that neurons in the anterior division of the superior temporal polysensory area (STPa) of monkeys can selectively respond to three-dimensional structure-from-motion. Monkeys performed a reaction time...

Increased safety has been advocated as one of the major benefits introduction Automated Driving Systems (ADSs). Incorporation ADSs in vehicles means that associated software critical application, thus requiring exhaustive testing. To prove are safer than human drivers, some work suggested they will need to be driven for over 11 billion miles. The number test miles is not, by itself, a meaningfu...

The histone-like nucleoid structuring protein (H-NS) has played a key role in shaping the evolution of Shigella spp., and provides the backdrop to the regulatory cascade that controls virulence by silencing many genes found on the large virulence plasmid. H-NS and its paralogue StpA are present in all four Shigella spp., but a second H-NS paralogue, Sfh, is found in the Shigella flexneri type s...