High frequency protection scheme for multi-terminal HVDC overhead lines

This paper proposes a novel protective relaying technique for multi-terminal HVDC system based on the high frequency components in the current signals received at each end of the DC transmission line. A simple model of a mono-pole, ground return, MTDC system is built in ATP draw using a distributed parameter, frequency dependent overhead line model. For this system, the high frequency content in the current signal directly following a fault (at approximately 0.2 kHz) is shown to vary significantly with fault location but not fault resistance. The protection algorithm is then validated in real time using an RTDS system, where both the ATP primary system model and the MATLAB developed algorithm are demonstrated in a real time context

Urban development and visual culture: Commodifying the gaze in the regeneration of Tigné Point, Malta

This paper explores some of the hitherto under-researched intersections between urban (re)development, urban planning and visual culture. What emerges is an academic context that, to date, has largely compartmentalised discrete literatures on ‘view’, ‘value of the view’ and cityscape change, (re)Imagineering and (re)scripting). It shows how materialising processes associated with the commodification of a panoramic view in politico-economic and cultural terms can be used to transform and regenerate along neoliberal lines. It demonstrates how panoramas, when treated as a commodity within the context of neoliberal capitalism, are appropriated, (re)imagined and (re)scripted by architects and property developers to create high status, residential and commercial space for an affluent élite. As such, panoramas are a mechanism for the acceleration of capital accumulation that inherently create new and reinforce existing spatial inequalities. This study draws on research into the commodification of the view of the historic city of Valletta in the redevelopment of Tigné Point, the largest, most comprehensive regeneration scheme in Malta in recent years

Spatiotemporal predictions of soil properties and states in variably saturated landscapes

Understanding greenhouse gas (GHG) fluxes from landscapes with variably saturated soil conditions is challenging given the highly dynamic nature of GHG fluxes in both space and time, dubbed hot spots, and hot moments. On one hand, our ability to directly monitor these processes is limited by sparse in situ and surface chamber observational networks. On the other hand, remote sensing approaches provide spatial data sets but are limited by infrequent imaging over time. We use a robust statistical framework to merge sparse sensor network observations with reconnaissance style hydrogeophysical mapping at a well‐characterized site in Ohio. We find that combining time‐lapse electromagnetic induction surveys with empirical orthogonal functions provides additional environmental covariates related to soil properties and states at high spatial resolutions (~5 m). A cross‐validation experiment using eight different spatial interpolation methods versus 120 in situ soil cores indicated an ~30% reduction in root‐mean‐square error for soil properties (clay weight percent and total soil carbon weight percent) using hydrogeophysical derived environmental covariates with regression kriging. In addition, the hydrogeophysical derived environmental covariates were found to be good predictors of soil states (soil temperature, soil water content, and soil oxygen). The presented framework allows for temporal gap filling of individual sensor data sets as well as provides flexible geometric interpolation to complex areas/volumes. We anticipate that the framework, with its flexible temporal and spatial monitoring options, will be useful in designing future monitoring networks as well as support the next generation of hyper‐resolution hydrologic and biogeochemical models

Urban Biodiversity and Landscape Ecology: Patterns, Processes and Planning

Effective planning for biodiversity in cities and towns is increasingly important as urban areas and their human populations grow, both to achieve conservation goals and because ecological communities support services on which humans depend. Landscape ecology provides important frameworks for understanding and conserving urban biodiversity both within cities and considering whole cities in their regional context, and has played an important role in the development of a substantial and expanding body of knowledge about urban landscapes and communities. Characteristics of the whole city including size, overall amount of green space, age and regional context are important considerations for understanding and planning for biotic assemblages at the scale of entire cities, but have received relatively little research attention. Studies of biodiversity within cities are more abundant and show that longstanding principles regarding how patch size, configuration and composition influence biodiversity apply to urban areas as they do in other habitats. However, the fine spatial scales at which urban areas are fragmented and the altered temporal dynamics compared to non-urban areas indicate a need to apply hierarchical multi-scalar landscape ecology models to urban environments. Transferring results from landscape-scale urban biodiversity research into planning remains challenging, not least because of the requirements for urban green space to provide multiple functions. An increasing array of tools is available to meet this challenge and increasingly requires ecologists to work with planners to address biodiversity challenges. Biodiversity conservation and enhancement is just one strand in urban planning, but is increasingly important in a rapidly urbanising world

Prognostic model to predict postoperative acute kidney injury in patients undergoing major gastrointestinal surgery based on a national prospective observational cohort study.

Background: Acute illness, existing co-morbidities and surgical stress response can all contribute to postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. The aim of this study was prospectively to develop a pragmatic prognostic model to stratify patients according to risk of developing AKI after major gastrointestinal surgery. Methods: This prospective multicentre cohort study included consecutive adults undergoing elective or emergency gastrointestinal resection, liver resection or stoma reversal in 2-week blocks over a continuous 3-month period. The primary outcome was the rate of AKI within 7 days of surgery. Bootstrap stability was used to select clinically plausible risk factors into the model. Internal model validation was carried out by bootstrap validation. Results: A total of 4544 patients were included across 173 centres in the UK and Ireland. The overall rate of AKI was 14·2 per cent (646 of 4544) and the 30-day mortality rate was 1·8 per cent (84 of 4544). Stage 1 AKI was significantly associated with 30-day mortality (unadjusted odds ratio 7·61, 95 per cent c.i. 4·49 to 12·90; P < 0·001), with increasing odds of death with each AKI stage. Six variables were selected for inclusion in the prognostic model: age, sex, ASA grade, preoperative estimated glomerular filtration rate, planned open surgery and preoperative use of either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. Internal validation demonstrated good model discrimination (c-statistic 0·65). Discussion: Following major gastrointestinal surgery, AKI occurred in one in seven patients. This preoperative prognostic model identified patients at high risk of postoperative AKI. Validation in an independent data set is required to ensure generalizability

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Importance and controls of anaerobic ammonium oxidation influenced by riverbed geology

Rivers are an important global sink for excess bioavailable nitrogen: they convert approximately 40% of terrestrial N runoff per year (∼47 Tg) to biologically unavailable N 2 gas and return it to the atmosphere. At present, riverine N 2 production is conceptualized and modelled as denitrification. Anaerobic ammonium oxidation, known as anammox, is an alternative pathway of N 2 production important in marine environments, but its contribution to riverine N 2 production is not well understood. Here we use in situ and laboratory measurements of anammox activity using 15 N tracers and molecular analyses of microbial communities to evaluate anammox in clay-, sand-and chalk-dominated river beds in the Hampshire Avon catchment, UK during summer 2013. Abundance of the hzo gene, which encodes an enzyme central to anammox metabolism, varied across the contrasting geologies. Anammox rates were similar across geologies but contributed different proportions of N 2 production because of variation in denitrification rates. In spite of requiring anoxic conditions, anammox, most likely coupled to partial nitrification, contributed up to 58% of in situ N 2 production in oxic, permeable riverbeds. In contrast, denitrification dominated in low-permeability clay-bed rivers, where anammox contributes roughly 7% to the production of N 2 gas. We conclude that anammox can represent an important nitrogen loss pathway in permeable river sediments