Numerical modeling of Mach-stem formation in high-amplitude time-reversal focusing.

In acoustics, time-reversal processing is commonly used to exploit multiple scatterings in reverberant environments to focus sound to a specific location. Recently, the nonlinear characteristics of time-reversal focusing at amplitudes as high as 200 dB have been reported [Patchett and Anderson, J. Acoust.

Oxygen impact and reactivity trials: A new perspective on emergency response precautions.

The objective of this research was to verify and qualify what has been traditionally taught as fact during first responder's hazardous materials training regarding response precautions to and the likely behaviors of liquid oxygen (LOx) during a release. Subject matter experts disagreed that these precautions were well-founded in precedent or science. Findings showed that impact pressure causes a reaction in LOx and asphalt under specific conditions.

Allergic Polysensitization Clusters: Newly Recognized Severity Marker in Urban Asthmatic Adults.

Introduction: While reliable, quantitative in vitro testing for sensitivity to aeroallergens has been available for decades, such information has largely been ignored in clustering analyses of asthma. Our aim is to explore allergic polysensitization as a possible marker of asthma severity and, as such, to be considered as an integral marker in future asthma clustering analyses.

Methods: We constructed a database of sensitizations to the 25 aeroallergens in our geographic area (zone 1, Northeastern US) using the ImmunoCAP® in vitro assay.

Nonlinear characteristics of high amplitude focusing using time reversal in a reverberation chamber.

Time reversal (TR) signal processing is an effective tool to exploit a reverberant environment for the intentional focusing of airborne, audible sound. A previous room acoustics TR study found preliminary evidence that above a certain focal amplitude the focal waveform begins to display signs of nonlinearity [Willardson, Anderson, Young, Denison, and Patchett, J. Acoust.

The impact of room location on time reversal focusing amplitudes.

Time reversal (TR) is a signal processing technique often used to generate focusing at selected positions within reverberant environments. This study investigates the effect of the location of the focusing, with respect to the room wall boundaries, on the amplitude of the focusing and the uniformity of this amplitude when focusing at various room locations. This is done experimentally with eight sources and two reverberation chambers.

and fungal endophyte associations: host status for and nematotoxic plant extracts.

hybrids are forage grasses used worldwide in temperate climates. They are associated with the fungal endophyte , which aids in nutrient uptake, drought tolerance, and production of metabolites that protect against parasites and herbivores. produces loline alkaloids, which can deter insect pests.

Time reversal focusing of high amplitude sound in a reverberation chamber.

Time reversal (TR) is a signal processing technique that can be used for intentional sound focusing. While it has been studied in room acoustics, the application of TR to produce a high amplitude focus of sound in a room has not yet been explored. The purpose of this study is to create a virtual source of spherical waves with TR that are of sufficient intensity to study nonlinear acoustic propagation.

Epichloë uncinata Infection and Loline Content Protect Festulolium Grasses From Crickets (Orthoptera: Gryllidae).

Experiments with artificial diets demonstrated that black field cricket (Teleogryllus commodus (Walker)) and Lepidogryllus sp. were highly responsive to presence of lolines in their diet-quantities of diet consumed declined exponentially with increasing loline concentration. Amount consumed by black field cricket and Lepidogryllus sp.

Excretion of loline alkaloids in urine and faeces of sheep dosed with meadow fescue (Festuca pratensis) seed containing high concentrations of loline alkaloids.

Aim: To determine the effect of oral dosing of sheep with loline alkaloids on their excretion in urine and faeces, and to monitor for any toxic effects.

Methods: In Experiment 1, six 9-month-old ewe lambs were given a single oral dose of loline alkaloids (52 mg/kg bodyweight (BW); acute exposure) as a suspension of ground meadow fescue (Festuca pratensis) seed in water. In Experiment 2, on six consecutive days, six ewe lambs were given three doses of loline (68 mg/kg BW/day; chronic exposure).