Resolved-sideband laser cooling in a penning trap

We report the laser cooling of a single $^{40}\text{Ca}^+$ ion in a Penning trap to the motional ground state in one dimension. Cooling is performed in the strong binding limit on the 729-nm electric quadrupole $S_{1/2}\leftrightarrow D_{5/2}$ transition, broadened by a quench laser coupling the $D_{5/2}$ and $P_{3/2}$ levels. We find the final ground state occupation to be $98\pm1\%$. We measure the heating rate of the trap to be very low with $\dot{\bar{n}}\approx 0.3\pm0.2\textrm{s}^{-1}$ for trap frequencies from $150-400\textrm{kHz}$, consistent with the large ion-electrode distance.Comment: 4 pages, 6 figures. Accepted: Phys. Rev. Lett. (2016) http://journals.aps.org/prl/accepted/b6074YefH1115b5881f77975417a6ae0bc9f652a

Annotation of Medieval Music Facsimiles Using ‘Good Enough’ OMR

The Clausula Archive of the Notre Dame Repertory (CANDR) is an in-progress PhD project with the aim of cataloguing, transcribing and analysing digital facsimiles of the thirteenth-century repertory commonly termed Notre Dame polyphony, and a secondary aim of providing new datasets and analytical tools for studying medieval polyphony. This poster highlights the use in the project of (a) a new methodology for de-skewing facsimile images, and (b) average symbol masks in an OMR–enhanced workflow with an emphasis on creating an OMR workflow that is ‘good enough’ to accelerate the annotation of an image dataset of particularly transitional notation

Comment on : 'multi-element signatures of stream sediments and sources under moderate to low flow conditions' by M.I. Stutter, S.J. Langan, D.G. Lumsdon, L.M. Clark

In a recent paper on ‘Multi-element signatures of stream sediments and sources under moderate to low flow conditions’, Stutter et al., 2009 M.I. Stutter, S.J. Langan, D.G. Lumsdon and L.M. Clark, Multi-element signatures of stream sediments and sources under moderate to low flow conditions, Appl. Geochem. 24 (2009), pp. 800–809. Article | PDF (392 K) | View Record in Scopus | Cited By in Scopus (2)Stutter et al. (2009) presented results of a simple sediment source tracing method based on major and trace elements for a small agricultural catchment in NE Scotland. The authors reported statistically significant, larger concentrations of four trace elements (Ce, Nd, Th and Y) in bank subsoils (n = 5) and stream bed sediments (n = 3) compared to topsoils from both pasture (n = 5) and arable (n = 5) land. They used these differences to aid discrimination between topsoil and subsoil (stream bank erosion) contributions to bed sediment. These elements may be more depleted in topsoil compared to subsoil because the former have been subject to more intense weathering over a longer period. If these naturally occurring trace elements could be used to understand the relative proportions of topsoil and subsoil contributions to headwater bed sediments this approach might be applied more widely to elucidate transport pathways for the transfer of agricultural contaminants such as particulate phosphorus to streams (Walling et al., 2008). This approach warrants further investigation across a range of catchments at different scales with contrasting land use and bedrock types. This can be undertaken using data from regional-scale geochemical surveys (Johnson et al., 2005) which include analyses of both stream bed sediments and subsoil samples. Previous studies have shown that much of lowland central England is at risk of topsoil transfer to watercourses via land drains (Chapman et al., 2003). A geochemical survey across part of central England covering 15 400 km2 was recently undertaken and these data are well-suited to testing whether three of the four trace elements identified by Stutter et al. (2009) might be used to discriminate between topsoil and subsoil in sediments more widely. Specifically, if the concentrations of these elements are significantly smaller in stream bed sediments than in the subsoil, this may be due to mixing with topsoils which have lower concentrations of these elements. Below the regional-scale survey, the methods the author used to compare the geochemical data in subsoil and bed sediments described, and the findings and their implications discussed

The musical, notational and codicological evidence of W1 for an oral transmission of Notre Dame polyphony to Scotland

The repertory of thirteenth–century polyphony commonly known as the Notre Dame school has traditionally been thought of as one of the first repertories of music to have emerged through composition rather than improvisation. Often conceived of as a product of the work of two men, Léonin and Pérotin, who each contributed to the creation of a ‘Magnus Liber Organi’ and began this tradition, Notre Dame polyphony is frequently discussed as the first polyphonic music to have been conceived in writing. Of the central manuscripts that contain this supposed ‘Magnus Liber Organi’, D-W Cod. Guelf. 628 Helmst. (W1) is the most difficult to fit into the standard view of the repertory, as its provenance from St Andrews in Scotland places it far beyond the Parisian milieu that is usually associated with the repertory. The question of how this music came to be transmitted from Paris to St Andrews has never been satisfactorily answered, leaving open questions as to who, how, and why the music was transmitted to and written down in Scotland. Reframing the discussion as an issue of cultural phenomena rather than literate music composition, I argue that indications of Notre Dame polyphony being transmitted orally rather than through exemplar manuscripts are not as far–fetched as many believe. This is due in part to our modern distrust of oral transmission, a conception of the Notre Dame repertory as a prototype of the Western art music tradition, as well as an academic failure to move beyond the flawed assumptions of much twentieth–century scholarship. Analysing the music and notation of W1 in comparison to concordant settings in other manuscripts, I bring to the forefront those large and small divergences between the music and its notation that indicate aspects of an oral tradition present in the writing of W1. I argue that these differences provide evidence to support a theory that Notre Dame polyphony was transmitted orally and was not likely to have been transmitted by direct manuscript transmission between far–flung liturgical institutions such as Notre Dame and St Andrews; rather, that Notre Dame polyphony was a pan-European cultural and musical phenomenon that spread gradually throughout Europe through oral–formulaic processes

Catchment Typologies Workshop report, Feb 2017, Edinburgh

This report summarises the discussion and outcomes of a workshop held in Edinburgh in February 2017 to further an area of work on catchment typologies under the Scottish Government’s strategic research programme area on waters. The workshop was organised and facilitated by a project team from the James Hutton Institute and Centre for Ecology & Hydrology. Key stakeholders were invited that represented regulatory and academic interests that are developing and using typology based approaches, and other aspects of spatial data synthesis, for determining grouped behaviours among catchment functions, especially in relation to risks of waterbody responses. The aims of the workshop were to: i) introduce the context of catchment typologies and gain a common understanding; ii) share experiences and establish gaps and opportunities; iii) explore the practicalities of developing typology based approaches; and iv) share next steps in this area of work with key stakeholders. The following synthesis and conclusions result from a set of introductory talks and a two way dialogue with stakeholders. Typologies can be a useful approach to representing grouped behaviours across spatial data relating to catchment functions and waterbody (i.e. receptor) impacts. As such, they can represent commonalities in susceptibilities to multiple interacting stressors. This was thought to be especially useful when combined with risk based approaches that facilitate transfer from data rich to data poor areas or from present to future. There remains a need, however, to communicate the concept of typologies (or our distinct use of them) and terminology such as ‘catchment families’ in a simple way. This may prove useful to non-specialists as a way of conveying grouped behaviours and underlying common ‘ancestry’ within change trajectories. Scaling of typology based approaches to address specific research and operational needs was considered especially important, for input data and outputs, and for different spatial and temporal scales (including, for example, longer-term changes and ‘shocks’ due to extreme events in waterbodies). Satisfying data requirements will constrain the development of typologies and the group acknowledged a role for modelling in filling data gaps, with a need to communicate uncertainty. Good examples of community based approaches to data acquisition, sharing, online and statistical tools were shown from the United States (National Stream Internet project, USDA) and the group recognised that softening institutional barriers and promoting better sharing of data and resources would accelerate the typologies approaches and lead to better outcomes. Finally, specific areas of application of typologies were discussed in relation to a set of case studies. These are detailed in the conclusions to this report

Trapped-ion quantum error-correcting protocols using only global operations

Quantum error-correcting codes are many-body entangled states that are prepared and measured using complex sequences of entangling operations. Each element of such an entangling sequence introduces noise to delicate quantum information during the encoding or reading out of the code. It is important therefore to find efficient entangling protocols to avoid the loss of information. Here we propose an experiment that uses only global entangling operations to encode an arbitrary logical qubit to either the five-qubit repetition code or the five-qubit code, with a six-ion Coulomb crystal architecture in a Penning trap. We show that the use of global operations enables us to prepare and read out these codes using only six and ten global entangling pulses, respectively. The proposed experiment also allows the acquisition of syndrome information during readout. We provide a noise analysis for the presented protocols, estimating that we can achieve a six-fold improvement in coherence time with noise as high as $\sim 1\%$ on each entangling operation.Comment: 7 pages, 4 figures, published version, comments are welcom

Dissolved organic carbon dynamics in a UK podzolic moorland catchment: linking storm hydrochemistry, flow path analysis and sorption experiments

Better knowledge of spatial and temporal delivery of dissolved organic carbon (DOC) in small catchments is required to understand the mechanisms behind reported long-term changes in C fluxes from some peatlands. We monitored two storms with contrasting seasons and antecedent conditions in a small upland UK moorland catchment. We examined DOC concentrations and specific UV absorbance (SUVA at 285 nm), together with solute concentrations required to undertake end-member mixing analyses to define dominant flow paths contributing to streamflow. This was combined with laboratory soil-solution equilibrations. We aimed to resolve how seasonal biogeochemical processing of DOC and flowpath changes in organo-mineral soils combine to affect DOC exported via the stream. An August storm following a dry period gave maximum DOC concentration of 10 mg l<sup>−1</sup>. Small DOC:DON ratios (16–28) and SUVA (2.7–3.6 l mg<sup>−1</sup> m<sup>−1</sup>) was attributed to filtration of aromatic compounds associated with up to 53% B horizon flow contributions. This selective filtration of high SUVA DOC was reproduced in the experimental batch equilibration system. For a November storm, wetter antecedent soil conditions led to enhanced soil connectivity with the stream and seven times greater DOC stream-load (maximum concentration 16 mg l<sup>−1</sup>). This storm had a 63% O horizon flow contribution at its peak, limited B horizon buffering and consequently more aromatic DOC (SUVA 3.9–4.5 l mg<sup>−1</sup> m<sup>−1</sup> and DOC:DON ratio 35–43). We suggest that simple mixing of waters from different flow paths cannot alone explain the differences in DOC compositions between August and November and biogeochemical processing of DOC is required to fully explain the observed stream DOC dynamics. This preliminary evidence is in contrast to other studies proposing hydrological controls on the nature of DOC delivered to streams. Although our study is based only on two storms of very different hydrological and biogeochemical periods, this should promote wider study of DOC biogeochemical alteration in headwaters so that this be better incorporated in modelling to predict the impacts of changes in DOC delivery to, and fate in, aquatic systems

The social life of street food: exploring the social sustainability of street food in Hanoi, Vietnam

This research explores the social life of street food in Hanoi, Vietnam, using a conceptual framework of social sustainability. Although the economic benefits of street vending are widely recognised, little attention has previously been paid to the social aspects. Focusing specifically on the selling of street food through the lens of social sustainability, this research develops a conceptual framework from the literature. The framework comprised eight key themes: social justice, quality of life and well-being, participation, safety and security, social interactions and social networks, social inclusion, sense of place and cultural heritage and was applied empirically to the street food environment of Hanoi. The themes used in the framework were identified as the most pertinent in the literature and were grouped under three broad ideas – social justice, social relations and culture – and used to frame the thesis. The application of the social sustainability framework revealed important details about the social life and social function of the street food environment. It highlighted key areas where street food in Hanoi can be shown to contribute to the principles of social sustainability, such as regarding social relations, cultural heritage and sense of place. It also drew attention to areas that require improvement, including some aspects of social justice, for example, participation, safety and security and food hygiene. The findings of this research suggest the challenges identified that prevent the social sustainability of street food in Hanoi, often manifested themselves through the inequalities experienced between the different types of street food vendors, specifically itinerant or migrant vendors compared to local vendors with fixed selling locations. The thesis argues that the approach adopted in the research offers a useful tool for understanding the social functions of street vending which can be applied and adapted to examine the social sustainability of street food vending in other economic and political contexts

A tool for cost-effectiveness analysis of field scale sediment-bound phosphorus mitigation measures and application to analysis of spatial and temporal targeting in the Lunan Water catchment, Scotland

This work was funded by the Scottish Government Rural Environment and Rural Affairs (RESAS) department as part of their strategic research programme for 2011–2016 Theme 2: Water and Renewable Energy.Peer reviewedPublisher PD