Characteristics of Lawn and Garden Equipment Sound: A Community Pilot Study.

More than 11 million gas powered leaf blowers (GLB) operate in the US. Most are powered by inefficient 2-stroke engines. The noise is intolerable to some and many communities have enacted ordinances restricting their use. This pilot study aimed to characterize the low, medium, and high frequency sound components from commercial grade GLBs over distance, evaluate the adequacy of the A-weighted decibel (dB [A]) to describe this sound, and discuss the impact of GLB sound in a community setting. In a field experiment with 2 leaf blowers and a hose vacuum, the time averaged A-weighted dB(A) (LAEQ) and un-weighted dB (LEQ) metrics, and low, mid, and high frequency GLB sound components were evaluated at intervals out to 800 feet from point of operation (centroid). Sound levels at 50 feet for each GLB were consistent with manufacturer ratings. The sound from the 2 GLBs and hose vacuum exceeded 100 decibels for both LEQ and LAEQ at the centroid. At all distance intervals, LEQ was 11.2-12.5 decibels higher compared with LAEQ. With the exception of the high frequency dB, all sound metrics emitted from this equipment were found to exceed WHO outdoor daytime standards (55 dB) up to 800 feet away from the centroid. The dominance of the low frequency component over distance indicates that a dB-based metric is a more appropriate descriptor of this sound compared with a dB(A)-based metric. The loudness of GLB sound at point of operation is especially concerning for the auditory and non-auditory health of workers and others regularly exposed in close proximity. The ability of this sound - in particular its lower frequency components - to travel over long distances suggests that GLB sound has a wide ranging impact on surrounding communities and raises concerns over its adverse health impacts.

Measuring the cost-effectiveness of midwife-led versus physician-led intrapartum teams in developing countries.

International agencies have advocated scaling-up of midwifery resources as an important method for improving maternal health and reducing maternal mortality rates (MMR). The cost-effectiveness of midwife-led versus physician-led intrapartum care is an important consideration in the human resource planning required to reduce MMR. Studies suggest that midwife-led teams can achieve comparable effectiveness and outcomes using less medically intensive care compared with physician-led teams. In the absence of adequate medical cost data, decision makers should consider the substantially lower average costs for three main drivers: salaries, benefits and incentives (≥two-times lower); preservice training (three-times lower) and attrition (two-times lower) necessary to deliver intrapartum care at the level of midwife competencies. This suggests that scale-up of midwifery resources is a less expensive and more cost-effective way to reduce MMRs and could potentially increase access to skilled intrapartum care.

Outcomes validity and reliability of the modified Rankin scale: implications for stroke clinical trials: a literature review and synthesis.

BACKGROUND AND PURPOSE: The modified Rankin scale (mRS), a clinician-reported measure of global disability, is widely applied for evaluating stroke patient outcomes and as an end point in randomized clinical trials. Extensive evidence on the validity of the mRS exists across a large but fragmented literature. As new treatments for acute ischemic stroke are submitted for agency approval, an appreciation of the mRS's attributes, specifically its relationship to other stroke evaluation scales, would be valuable for decision-makers to properly assess the impact of a new drug on treatment paradigms. The purpose of this report is to assemble and systematically assess the properties of the mRS to provide decision-makers with pertinent evaluative information. METHODS: A Medline search was conducted to identify reports in the peer-reviewed medical literature (1957-2006) that provide information on the structure, validation, scoring, and psychometric properties of the mRS and its use in clinical trials. The selection of articles was based on defined criteria that included relevance, study design and use of appropriate statistical methods. RESULTS: Of 224 articles identified by the literature search, 50 were selected for detailed assessment. Inter-rater reliability with the mRS is moderate and improves with structured interviews (kappa 0.56 versus 0.78); strong test-re-test reliability (kappa=0.81 to 0.95) has been reported. Numerous studies demonstrate the construct validity of the mRS by its relationships to physiological indicators such as stroke type, lesion size, perfusion and neurological impairment. Convergent validity between the mRS and other disability scales is well documented. Patient comorbidities and socioeconomic factors should be considered in properly applying and interpreting the mRS. Recent analyses suggest that randomized clinical trials of acute stroke treatments may require a smaller sample size if the mRS is used as a primary end point rather than the Barthel Index. CONCLUSIONS: Multiple types of evidence attest to the validity and reliability of the mRS. The reported data support the view that the mRS is a valuable instrument for assessing the impact of new stroke treatments.