Resonant nonlinear magneto-optical effects in atoms

In this article, we review the history, current status, physical mechanisms, experimental methods, and applications of nonlinear magneto-optical effects in atomic vapors. We begin by describing the pioneering work of Macaluso and Corbino over a century ago on linear magneto-optical effects (in which the properties of the medium do not depend on the light power) in the vicinity of atomic resonances, and contrast these effects with various nonlinear magneto-optical phenomena that have been studied both theoretically and experimentally since the late 1960s. In recent years, the field of nonlinear magneto-optics has experienced a revival of interest that has led to a number of developments, including the observation of ultra-narrow (1-Hz) magneto-optical resonances, applications in sensitive magnetometry, nonlinear magneto-optical tomography, and the possibility of a search for parity- and time-reversal-invariance violation in atoms.Comment: 51 pages, 23 figures, to appear in Rev. Mod. Phys. in Oct. 2002, Figure added, typos corrected, text edited for clarit

Stakeholder perspectives on shale gas fracking: A Q-method study of environmental discourses

The rapid expansion of shale gas exploration worldwide is a significant source of environmental controversy. Successful shale gas policymaking is dependent upon a clear understanding of the dynamics of competing stakeholder perspectives on these issues, and so methods are needed to delineate the areas of agreement and conflict that emerge. This empirical study, based in the United Kingdom, examines emergent perspectives on a range of environmental, health and socio-economic impacts associated with shale gas fracking using Q- methodology: a combined qualitative-quantitative approach. The analysis reveals three typologies of perspectives amongst key industry, civil society and non-affiliated citizen stakeholders; subsequently contextualised in relation to Dryzek’s typology of environmental discourses. These are labelled A) “Don’t trust the fossil fuels industry: campaign for renewables” (mediating between sustainable development and democratic pragmatism discourses); B) “Shale gas is a bridge fuel: economic growth and environmental scepticism” (mediating between economic rationalism and ecological modernisation discourses); and C) “Take place protective action and legislate in the public interest” (reflecting a discourse of administrative rationalism). The implications of these competing discourses for nascent shale gas policy in the UK are discussed in light of recent Government public consultation on changes to national planning policy

Evolving Discourses on Water Resource Management and Climate Change in the Equatorial Nile Basin

Transboundary water resources management in the Equatorial Nile Basin (EQNB) is a politically contested issue. There is a growing body of literature examining water-related discourses which identifies the ability of powerful actors and institutions to influence policy. Concern about the effects of future climate change has featured strongly in research on the Nile River for several decades. It is therefore timely to consider whether and how these concerns are reflected in regional policy documents and policy discourse. This study analyzes discourse framings of water resources management and climate change in policy documents (27, published between 2001 and 2013) and as elicited in interviews (38) with water managers in the EQNB. Three main discursive framings are identified which are present in the discourses on both subjects: a problem-oriented environmental risk frame and two solution-oriented frames, on governance and infrastructure development. Climate change discourse only emerges as a common topic around 2007. The framings found in the water resources management discourse and the climate change discourse are almost identical, suggesting that discursive framings were adopted from the former for use in the latter. We infer that the climate change discourse may have offered a less politically sensitive route to circumvent political sensitivities around water allocation and distribution between riparian countries in the EQNB. However, the climate change discourse does not offer a lasting solution to the more fundamental political dispute over water allocation. Moreover, in cases where the climate change discourse is subsumed within a water resources management discourse, there are dangers that it will not fully address the needs of effective adaptation

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Existing heavy liquid metal facilities for experimental applications

The use of the heavy liquid metals (HLM), lead-bismuth eutectic (LBE) and lead (Pb) as cooling mediums and spallation material has been envisaged for accelerator-driven systems (ADS), which are devoted to transmutation, thus reducing the burden of nuclear waste. An increasing interest in HLM has also been identified in other research and industrial fields, for instance energy production with advanced nuclear systems, e.g. the lead-cooled fast reactor (LFR), hydrogen production and the development of spallation neutron sources for medical applications and materials studies. Moreover, HLM might also play a future role in the development of concentrated solar power plants. Therefore, scientific and technological activities focused on materials compatibility, thermal fluid dynamics characterisation and technology issues have been launched. In this framework a great effort has been made in Europe, Japan, Korea and the United States since the late 1990s to build and operate HLM test facilities in support of the previously mentioned applications. In the following paragraphs updated descriptions of the HLM facilities available at the laboratories of the expert groups participating in the realisation of this handbook are given. An updated list of the facilities is also given in Table 12.4.1 at the end of this chapter. The update has been done with respect to the 2007 version of the HLM handbook, as new facilities have been built and existing facilities have been refurbished or dismantled. In particular, the new and existing facilities built in Europe as well as the future needs have been analysed within the Advanced Reactor Initiative and Network Arrangement (ADRIANA) project. The outcomes of this project and the input received from the experts have been used to update the chapter. As far as the dismantled facilities are concerned, these have been removed from this edition of the handbook.JRC.E-Institute for Transuranium Elements (Karlsruhe