Manganese abundances in mercury-manganese stars

We use exact curve-of-growth analysis and spectral synthesis to deduce the abundance of Mn from high signal-to-noise ratio visible-region echelle spectra of selected Mn i and MnII lines in 24 HgMn stars. The results are compared with the Mn abundances derived from UV resonance lines by Smith & Dworetsky. We find excellent agreement for several unblended Mn lines and confirm the temperature dependence of the Mn abundance found by Smith & Dworetsky. The MnII lines at λλ 4206 and 4326 are much stronger than one would predict from the mean Mn abundances. The lack of agreement is greatest for stars with the strongest MnII lines. Using ad hoc multicomponent fits to the profiles of sharp-lined stars, we show that most of the discrepancies can be explained by hyperfine structure that desaturates the lines, with full widths of the order of 0.06--0.09 Å

Expressiveness of Temporal Query Languages: On the Modelling of Intervals, Interval Relationships and States

Storing and retrieving time-related information are important, or even critical, tasks on many areas of Computer Science (CS) and in particular for Artificial Intelligence (AI). The expressive power of temporal databases/query languages has been studied from different perspectives, but the kind of temporal information they are able to store and retrieve is not always conveniently addressed. Here we assess a number of temporal query languages with respect to the modelling of time intervals, interval relationships and states, which can be thought of as the building blocks to represent and reason about a large and important class of historic information. To survey the facilities and issues which are particular to certain temporal query languages not only gives an idea about how useful they can be in particular contexts, but also gives an interesting insight in how these issues are, in many cases, ultimately inherent to the database paradigm. While in the area of AI declarative languages are usually the preferred choice, other areas of CS heavily rely on the extended relational paradigm. This paper, then, will be concerned with the representation of historic information in two well known temporal query languages: it Templog in the context of temporal deductive databases, and it TSQL2 in the context of temporal relational databases. We hope the results highlighted here will increase cross-fertilisation between different communities. This article can be related to recent publications drawing the attention towards the different approaches followed by the Databases and AI communities when using time-related concepts

The Road to Quantum Computational Supremacy

We present an idiosyncratic view of the race for quantum computational supremacy. Google's approach and IBM challenge are examined. An unexpected side-effect of the race is the significant progress in designing fast classical algorithms. Quantum supremacy, if achieved, won't make classical computing obsolete.Comment: 15 pages, 1 figur

Panarchy use in environmental science for risk and resilience planning

Environmental sciences have an important role in informing sustainable management of built environments by providing insights about the drivers and potentially negative impacts of global environmental change. Here, we discuss panarchy theory, a multi-scale hierarchical concept that accounts for the dynamism of complex socio-ecological systems, especially for those systems with strong cross-scale feedbacks. The idea of panarchy underlies much of system resilience, focusing on how systems respond to known and unknown threats. Panarchy theory can provide a framework for qualitative and quantitative research and application in the environmental sciences, which can in turn inform the ongoing efforts in sociotechnical resilience thinking and adaptive and transformative approaches to managemen

Evidence of Recent Active Volcanism in the Balleny Islands (Antarctica) From Ice Core Records

Abstract: Volcanism can play a key role in modulating climate; however, a lack of historical records has limited our comprehension of Antarctic volcanism and its role on the cryosphere. Remote sensing can provide insight into active volcanism in Antarctica during the satellite era, although the evidence is often inconclusive. Here, we use independent evidence from ice cores to validate one such potential volcanic eruption from the sub‐Antarctic Balleny Islands in 2001 CE. Multiple ice cores from downwind of the eruption site, record elevated input of sulfate, microparticles, and the presence of tephra, coincident with the eruption. In‐phase deposition of volcanic products confirmed a rapid tropospheric transport of volcanic emissions from a small‐to‐moderate, local eruption during 2001. Air mass trajectories demonstrated some air parcels were transported over the West Antarctic ice sheet from the Balleny Islands to ice core sites at the time of the potential eruption, establishing a route for transport and deposition of volcanic products over the ice sheet. The data presented here validate previous remote sensing observations and confirms a volcanic event in the Balleny Islands during 2001 CE. This newly identified eruption provides a case study of recent Antarctic volcanism

Time to go global: a consultation on global health competencies for postgraduate doctors

BACKGROUND: Globalisation is having profound impacts on health and healthcare. We solicited the views of a wide range of stakeholders in order to develop core global health competencies for postgraduate doctors. METHODS: Published literature and existing curricula informed writing of seven global health competencies for consultation. A modified policy Delphi involved an online survey and face-to-face and telephone interviews over three rounds. RESULTS: Over 250 stakeholders participated, including doctors, other health professionals, policymakers and members of the public from all continents of the world. Participants indicated that global health competence is essential for postgraduate doctors and other health professionals. Concerns were expressed about overburdening curricula and identifying what is 'essential' for whom. Conflicting perspectives emerged about the importance and relevance of different global health topics. Five core competencies were developed: (1) diversity, human rights and ethics; (2) environmental, social and economic determinants of health; (3) global epidemiology; (4) global health governance; and (5) health systems and health professionals. CONCLUSIONS: Global health can bring important perspectives to postgraduate curricula, enhancing the ability of doctors to provide quality care. These global health competencies require tailoring to meet different trainees' needs and facilitate their incorporation into curricula. Healthcare and global health are ever-changing; therefore, the competencies will need to be regularly reviewed and updated

Joining the conspiracy? Negotiating ethics and emotions in researching (around) AIDS in southern Africa

AIDS is an emotive subject, particularly in southern Africa. Among those who have been directly affected by the disease, or who perceive themselves to be personally at risk, talking about AIDS inevitably arouses strong emotions - amongst them fear, distress, loss and anger. Conventionally, human geography research has avoided engagement with such emotions. Although the ideal of the detached observer has been roundly critiqued, the emphasis in methodological literature on 'doing no harm' has led even qualitative researchers to avoid difficult emotional encounters. Nonetheless, research is inevitably shaped by emotions, not least those of the researchers themselves. In this paper, we examine the role of emotions in the research process through our experiences of researching the lives of 'Young AIDS migrants' in Malawi and Lesotho. We explore how the context of the research gave rise to the production of particular emotions, and how, in response, we shaped the research, presenting a research agenda focused more on migration than AIDS. This example reveals a tension between universalised ethics expressed through ethical research guidelines that demand informed consent, and ethics of care, sensitive to emotional context. It also demonstrates how dualistic distinctions between reason and emotion, justice and care, global and local are unhelpful in interpreting the ethics of research practice

Annual 30 m dataset for glacial lakes in High Mountain Asia from 2008 to 2017

Atmospheric warming is intensifying glacier melting and glacial-lake development in High Mountain Asia (HMA), and this could increase glacial-lake outburst flood (GLOF) hazards and impact water resources and hydroelectric-power management. There is therefore a pressing need to obtain comprehensive knowledge of the distribution and area of glacial lakes and also to quantify the variability in their sizes and types at high resolution in HMA. In this work, we developed an HMA glacial-lake inventory (Hi-MAG) database to characterize the annual coverage of glacial lakes from 2008 to 2017 at 30 m resolution using Landsat satellite imagery. Our data show that glacial lakes exhibited a total area increase of 90.14 km2 in the period 2008–2017, a +6.90 % change relative to 2008 (1305.59±213.99 km2). The annual increases in the number and area of lakes were 306 and 12 km2, respectively, and the greatest increase in the number of lakes occurred at 5400 m elevation, which increased by 249. Proglacial-lake-dominated areas, such as the Nyainqêntanglha and central Himalaya, where more than half of the glacial-lake area (summed over a 1∘ × 1∘ grid) consisted of proglacial lakes, showed obvious lake-area expansion. Conversely, some regions of eastern Tibetan mountains and Hengduan Shan, where unconnected glacial lakes occupied over half of the total lake area in each grid, exhibited stability or a slight reduction in lake area. Our results demonstrate that proglacial lakes are a main contributor to recent lake evolution in HMA, accounting for 62.87 % (56.67 km2) of the total area increase. Proglacial lakes in the Himalaya ranges alone accounted for 36.27 % (32.70 km2) of the total area increase. Regional geographic variability in debris cover, together with trends in warming and precipitation over the past few decades, largely explains the current distribution of supraglacial- and proglacial-lake area across HMA. The Hi-MAG database is available at https://doi.org/10.5281/zenodo.4275164 (Chen et al., 2020), and it can be used for studies of the complex interactions between glaciers, climate and glacial lakes, studies of GLOFs, and water resources

The spatial structure of the 128 ka Antarctic sea ice minimum

We compare multi-ice core data with δ18O model output for the early last interglacial Antarctic sea-ice minimum. The spatial pattern of δ18O across Antarctica is sensitive to the spatial pattern of sea-ice retreat. Local sea ice retreat increases the proportion of winter precipitation, depleting δ18O at ice core sites. However, retreat also enriches δ18O because of the reduced source to-site distance for atmospheric vapour. The joint overall effect is for δ18O to increase as sea ice is reduced. Our data-model comparison indicates a winter sea-ice retreat of 67, 59 and 43 % relative to pre-industrial in the Atlantic, Indian and Pacific sectors of the Southern Ocean. A compilation of Southern Ocean sea-ice proxy data provides weak support for this reconstruction. However, most published marine core sites are located too far north of the 128,000 years BP sea ice edge, preventing independent corroboration for this sea ice reconstruction.This work was funded by NERC grant numbers NE/P009271/1, NE/P013279/1 and NE/K004514/1. MH was also supported by the EPSRC-funded Past Earth Network (Grant number EP/M008363/1). EW is supported by a Royal Society Professorship