Asymmetric propagation of airblast from bench blasting

This paper investigates the propagation of airblast from quarry blasting. Peak overpressure is calculated as a function of blasting parameters (explosive mass per delay and velocity at which the detonation sequence proceeds along the bench) and polar coordinates of the point of interest (distance to the blast and azimuth with respect to the free face of the blast). The model is in the form of the product of a classical scaled distance attenuation law times a directional correction factor. The latter considers the influence of the bench face, and attenuates overpressure at the top level and amplifies it at the bottom. Such factor also accounts for the effect of the delay by amplifying the pressure in the direction of the initiation sequence if the velocity of initiation exceeds half the speed of sound and up to an initiation velocity in the range of the speed of sound. The model has been fitted to an empirical data set composed by 134 airblast records monitored in 47 blasts at two quarries. The measurements were made at distances to the blast less than 450 m. The model is statistically significant and has a determination coefficient of 0.869

Translocation and Functional Analysis of Pseudomonas savastanoi pv. savastanoi NCPPB 3335 Type III Secretion System Effectors Reveals Two Novel Effector Families of the Pseudomonas syringae Complex

Pseudomonas savastanoi pv. savastanoi NCPPB 3335 causes olive knot disease and is a model pathogen for exploring bacterial infection of woody hosts. The type III secretion system (T3SS) effector repertoire of this strain includes 31 effector candidates plus two novel candidates identified in this study which have not been reported to translocate into plant cells. In this work, we demonstrate the delivery of seven NCPPB 3335 effectors into Nicotiana tabacum leaves, including three proteins from two novel families of the P. syringae complex effector super-repertoire (HopBK and HopBL), one of which comprises two proteins (HopBL1 and HopBL2) that harbor a SUMO protease domain. When delivered by P. fluorescens heterologously expressing a P. syringae T3SS, all seven effectors were found to suppress the production of defense-associated reactive oxygen species. Moreover, six of these effectors, including the truncated versions of HopAA1 and HopAZ1 encoded by NCPPB 3335, suppressed callose deposition. The expression of HopAZ1 and HopBL1 by functionally effectorless P. syringae pv. tomato DC3000D28E inhibited the hypersensitive response in tobacco and, additionally, expression of HopBL2 by this strain significantly increased its competitiveness in N. benthamiana. DNA sequences encoding HopBL1 and HopBL2 were uniquely detected in a collection of 31 P. savastanoi pv. savastanoi strains and other P. syringae strains isolated from woody hosts, suggesting a relevant role of these two effectors in bacterial interactions with olive and other woody plants.