Environmental dependence of underwater sound propagation resulting from percussive pile driving [abstract]

Environmental dependence of underwater sound propagation resulting from percussive pile driving [abstract

Dynamic behaviour of laser nucleated bubbles in a focused ultrasound field

A reference facility to control the cavitation of single bubbles and bubble clouds, using optical and acoustic fields, has been designed and developed at the National Physical Laboratory, UK. The facility consists of a cuboid acoustic chamber, with optical windows on four sides and four transducers mounted on a truncated tetrahedron cap, a Q-switched laser, and an optical beam splitting system able to form either single or multiple beams. This work presents a characterization of this facility: the acoustic pressure field inside the acoustic chamber was measured with a combination of laser refractometry and hydrophone scans, to determine the locations where cavitation can be studied, while the optical threshold was quantified by observing nucleation as a function of the beam parameters. This work also presents some preliminary acoustic emission data and high-speed observations of bubble dynamics

Protocol for in-situ underwater measurement of explosive ordnance disposal for UXO

This document provides guidance on best practice for in-situ measurement of underwater sound generated from underwater explosions undertaken during disposal of unexploded ordnance in the ocean. In recent years there has been an increasing need to measure and report levels of underwater sound generated by these explosions, partly driven by the need to conform to regulatory requirements with regard to assessment of the environmental impact. Attempts to report measured noise levels are sometimes difficult to compare if different methodologies and acoustic metrics are used. This good practice guide aims to provide guidance on best practice for measurement and for reporting the results using common methodology. The work to prepare this document was funded in the UK by the Department for Business, Energy and Industrial Strategy through its Offshore Strategic Environmental Assessment programme.</p

Characterisation of acoustic fields generated by UXO removal phase 5 quarry trials of bubble curtain mitigation

This report describes part 1 of the work undertaken in the project Characterisation of acoustic fields generated by UXO removal - Phase 5. The aim was to investigate the effectiveness of small bubble curtains used as a barrier mitigation for the acoustic output from UXO during low-order disposal by conducting controlled experimental trials in a quarry facility. This work was funded by the UK Government’s Department for Business, Energy and Industrial Strategy (BEIS) through the Offshore Energy Strategic Environmental Assessment programme (OESEA), Sub-Contract OESEA-22-142. A total of nine explosive tests were undertaken during a two-day trial at the Limehillock Quary test facility in order to assess the attenuation of bubble curtain on the acoustic signal generated by underwater explosions. Three charge sizes were used of 45 g, 250 g and 465 g respectively, these being typical values in the range of charge sizes used on low-order techniques such as deflagration. Three air flow rates were used to generate a two-layer bubble curtain, with results presented for flows of 4.2 m3/min, 2.1 m3/min and no flow (no bubble curtain). The results demonstrate that, under the conditions of the experimental trial, the bubble curtains can achieve a reduction in peak sound pressure level of between 13 dB and 17 dB, and in Sound Exposure Level of between 7 dB and 8 dB. The results show promise for use of a small bubble curtain to provide additional mitigation during low-order deflagration disposals, and suggest that further work may be justified to optimise the technique. </p

Characterisation of acoustic fields generated by UXO removal Phase 5 quarry trials of ECS low-order technology

This report describes the work undertaken in the project Characterisation of acoustic fields generated by UXO removal: Phase 5. The aim was to investigate the effectiveness of low-order shaped charge technology supplied by ECS to reduce the acoustic output from UXO disposal compared to high-order detonation by conducting controlled experimental trials in a flooded quarry test facility (Limehillock Quarry). This work was funded by the UK Government’s Department for Business, Energy and Industrial Strategy (BEIS) through the Offshore Energy Strategic Environmental Assessment programme (OESEA), Sub-Contract OESEA-22-142. A total of 7 explosive tests were successfully conducted. These comprised two high-order tests on two sizes of surrogate munition (2.5 kg and 5.0 kg), two small shaped charges alone (35 g), and three small shaped charges (35 g) used as low-order deflagration charges against the larger surrogate munitions (two of 5.0 kg, one of 2.5 kg). All charges were detonated successfully and the acoustic radiated noise measured. The results show that the use of the low order technique is beneficial due to the significant reduction of acoustic levels. The results demonstrate that the low order charges used can achieve a reduction in peak sound pressure level of between 14 dB and 19 dB and in Sound Exposure Level of between 14 dB and 22 dB compared to high order detonation for charge sizes of 2.5 kg and 5.0 kg. Post-shot observations and weight measurements suggest that only a modest amount of the surrogate munition charge was consumed during the deflagration shots on the larger surrogates. </p

Screening Mammography Changes for Women <40 and 40–49.

<p>The mean number of screening mammograms per month performed in the health system from 2008 through 2012. Arrows indicate the times of new screening recommendations and implementation of the Affordable Care Act. Recommendations were associated with decreased screening for women <50, while the Affordable Care Act had no statistically significant associations.</p

Associations of Screening Recommendations and Affordable Care Act Implementation on Volume of Screening Mammography.

<p>^a2008 baseline estimation from each model. Although the sub-groups do not sum to the overall baseline estimate numerically, they are essentially the same when the uncertainty (SE) of the estimation is taken into account.</p><p>Associations of Screening Recommendations and Affordable Care Act Implementation on Volume of Screening Mammography.</p

Screening Mammograms by Age, n (row %).

<p>^aOther sources include self-pay and charity care.</p><p>Screening Mammograms by Age, n (row %).</p

Additional file 2: of Percutaneous closure versus medical therapy for stroke with patent foramen Ovale: a systematic review and meta-analysis

Figure S1. Flow diagram of study selection. Table S1. Main inclusion and exclusion criteria of included randomized trials. Table S2. Definitions of degree of shunting and atrial septal aneurysm in randomized trials. Table S3. Primary and secondary endpoints of included randomized trials. Table S4. Definitions of composite outcome, major bleeding, recurrent stroke and TIA in randomized trials. Table S5. Risk of bias of included randomized trials. Table S6. Study quality of included comparative observational studies using the Newcastle-Ottawa scale. Figure S2. The composite outcome of recurrent stroke, TIA and all-cause death with device closure versus medical therapy from randomized controlled trials and adjusted observational studies. Table S7. Subgroup analysis of the major outcomes based on study designs, number of patients and duration of follow-up. Table S8. Subgroup analysis of the composite outcome in randomized trials. Table S9. Subgroup analysis of recurrent ischemic stroke in randomized trials. Table S10. Meta-regression analysis in randomized trials exploring the potential for effect modification by multiple variables, including Moderate to severe PFO, atrial septal aneurysm, index event of stroke, and anticoagulation in medical treatment. (DOCX 594 kb

Additional file 1: of Percutaneous closure versus medical therapy for stroke with patent foramen Ovale: a systematic review and meta-analysis

PRISMA 2009 Checklist. (DOCX 29 kb