The Search for an Intelligible Principle: Setting Air Quality Standards under the Clean Air Act

Heather L. Ross weighs in on the controversy surrounding the EPA's setting of National Ambient Air Quality Standards. She forcefully argues that balancing costs and benefits is the only intelligible principle that comports with common sense.

Precursor Analysis for Offshore Oil and Gas Drilling: From Prescriptive to Risk-Informed Regulation

The Oil Spill Commission’s chartered mission—to “develop options to guard against … any oil spills associated with offshore drilling in the future” (National Commission 2010)—presents a major challenge: how to reduce the risk of low-frequency oil spill events, and especially high-consequence events like the Deepwater Horizon accident, when historical experience contains few oil spills of material scale and none approaching the significance of the Deepwater Horizon. In this paper, we consider precursor analysis as an answer to this challenge, addressing first its development and use in nuclear reactor regulation and then its applicability to offshore oil and gas drilling. We find that the nature of offshore drilling risks, the operating information obtainable by the regulator, and the learning curve provided by 30 years of nuclear experience make precursor analysis a promising option available to the U.S. Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE) to bring cost-effective, risk-informed oversight to bear on the threat of catastrophic oil spills.catastrophic oil spills, quantitative risk analysis, risk-informed regulation

Exchange Rate and Income Effects on South Korean Exports: The US Case

This paper analyzes econometrically the effects of direct and cross exchange rates as well as US income and Korean supply developments on the volume of Korean exports to the US. The results suggest that US demand has been the most important factor in the growth of Korean exports to the US in recent years. However, direct exchange rate effects are also important; the estimates suggest that for 1989-90, a yearly 10% real appreciation of the won against the dollar would have lowered export volume by about 10% per year relative to a baseline case. Cross exchange rate effects run counter to expectations

The dissociation of NO–Ar(A) from around threshold to 200 cm−1 above threshold

We report an investigation of the dissociation of A state NO–Ar at energies from 23 cm−1 below the dissociation energy to 200 cm−1 above. The NO product rotational distributions show population in states that are not accessible with the energy available for excitation from the NO ground state. This effect is observed at photon energies from below the dissociation energy up to approximately 100 cm−1 above it. Translational energy distributions, extracted from velocity map images of individual rotational levels of the NO product, reveal contributions from excitation of high energy NO–Ar X states at all the excess energies probed, although this diminishes with increasing photon energy and is quite small at 200 cm−1, the highest energy studied. These translational energy distributions show that there are contributions arising from population in vibrational levels up to the X state dissociation energy. We propose that the reason such sparsely populated levels contribute to the observed dissociation is a considerable increase in the transition moment, via the Franck–Condon factor associated with these highly excited states, which arises because of the quite different geometries in the NO–Ar X and A states. This effect is likely to arise in other systems with similarly large geometry changes

The binding energies of NO–Rg (Rg = He, Ne, Ar) determined by velocity map imaging

We report velocity map imaging measurements of the binding energies, D0, of NO–Rg (Rg = He, Ne, Ar) complexes. The X state binding energies determined are 3.0 ± 1.8, 28.6 ± 1.7, and 93.5 ± 0.9 cm−1 for NO–He, –Ne, and –Ar, respectively. These values compare reasonably well with ab initio calculations. Because the A–X transitions were unable to be observed for NO–He and NO–Ne, values for the binding energies in the A state of these complexes have not been determined. Based on our X state value and the reported A–X origin band position, the A state binding energy for NO–Ar was determined to be 50.6 ± 0.9 cm−1

A protocol for a systematic review of clinical guidelines and published systematic reviews on the early detection of oral cancer

Background: The predicted increase in incidence of oral cavity cancer (OCC) coupled with high mortality and poor prognosis – particularly when diagnosed at a late/advanced stage – highlights the need for prevention and early detection/screening to reverse these trends. Dental healthcare professionals in primary care settings have a pivotal role in this effort. Aim: The aim of this protocol is to detail the process for assessing the evidence for the best practice and methods of early detection/screening for OCC in primary care dental settings by undertaking a systematic review of global clinical guidelines and published systematic reviews. Method: Searches for clinical guidelines and systematic reviews will be conducted in the following databases: Cochrane library, Medical Literature Analysis and Retrieval System Online (Ovid), Excerpta Medical dataBASE, PubMed, Turning Research into Practice, SCOPUS and Web of Science Core Collection. Our search will extend to include Google Scholar and international professional organizations/associations websites. In addition, we will handsearch the bibliographies and undertake citation searches of the selected papers. Quality appraisal will be undertaken using the Appraisal of Guidelines for Research and Evaluation version II instrument for the clinical guidelines and both A MeaSurement Tool to Assess Systematic Reviews and Risk of Bias in Systematic Reviews tools for the systematic reviews. A narrative synthesis approach will be used to assess the evidence of extracted data, primarily taking account of quality appraisal and recency of publication. Discussion: The synthesis of evidence will determine best practice for OCC early detection/screening by primary care dental healthcare professionals and will evaluate the relationship between clinical guidelines and the evidence base available from systematic reviews in this area