Stabilisers as a design tool for new forms of Lechner-Hauke-Zoller Annealer

In a recent paper Lechner, Hauke and Zoller (LHZ) described a means to translate a Hamiltonian of $N$ spin-$\frac{1}{2}$ particles with 'all-to-all' interactions into a larger physical lattice with only on-site energies and local parity constraints. LHZ used this mapping to propose a novel form of quantum annealing. Here we provide a stabiliser-based formulation within which we can describe both this prior approach and a wide variety of variants. Examples include a triangular array supporting all-to-all connectivity, and moreover arrangements requiring only $2N$ or $N\log N$ spins but providing interesting bespoke connectivities. Further examples show that arbitrarily high order logical terms can be efficiently realised, even in a strictly 2D layout. Our stabilisers can correspond to either even-parity constraints, as in the LHZ proposal, or as odd-parity constraints. Considering the latter option applied to the original LHZ layout, we note it may simplify the physical realisation since the required ancillas are only spin-$\frac{1}{2}$ systems (i.e. qubits, rather than qutrits) and moreover the interactions are very simple. We make a preliminary assessment of the impact of this design choices by simulating small (few-qubit) systems; we find some indications that the new variant may maintain a larger minimum energy gap during the annealing process.Comment: A dramatically expanded revision: we now show how to use our stabiliser formulation to construct a wide variety of new physical layouts, including ones with fewer than Order N^2 spins but custom connectivities, and a means to achieve higher order coupling even in 2

Genetic factors affecting establishment during invasions : the introduction of the topmouth gudgeon (Pseudorasbora parva) and the rainbow trout (Oncorhynchus mykiss) in Europe

The study of biological invasions is a major research topic, both because of the ecological and economical damage caused by invasive species and also as a great natural experiment to study evolutionary responses of non-native populations to their new environment, and the factors influencing invasions. Introduced species often evolve rapidly, despite the assumed loss of genetic variation associated with bottlenecks during the invasion process. In order examine the processes and mechanisms affecting the outcome invasions I studied two non-native fish species, the topmouth gudgeon (Pseudorasbora parva) is an Asian cyprinid that is found in most European countries as a result of accidental introductions. Rainbow trout (Oncorhynchus mykiss) has been introduced from the United States for aquaculture and angling, however, despite numerous introductions, it has only been able to establish in few European waters. I used mitochondrial DNA and microsatellite markers to understand the invasion history of these species and the factors that influence their establishment success/failure. Part of the cytochrome b gene was analysed in European and native Asian P. parva populations and microsatellite markers were used to investigate the source populations of the species. The analyses elucidated the colonisation pattern of P. parva in Europe and supported the hypothesis that the species spread through long-distance and stepping-stone methods and originate from admixed source populations. In O. mykiss, part of the d-loop region of the mitochondrial genome was analysed to compare the phylogeographic structure of native US and introduced European populations to examine the spread of the species outside its native range, as well as to find out whether the resistant Hofer strain is the source population of the European rainbow trout populations. I found that European populations are likely to originate from various sources, mainly from California. The Hofer strain is likely to have contributed to some of the wild European populations. Assessing the role of these processes is fundamental in understanding invasive species and finding suitable management practices to control them. From an evolutionary point of view, I was able to detect some of the processes that are important during invasions, in these studies particularly the role of multiple introductions and introduction from genetically admixed source populations

Acidified and ultrafiltered recovered coagulants from water treatment works sludge for removal of phosphorus from wastewater

This study used a range of treated water treatment works sludge options for the removal of phosphorus (P) from primary wastewater. These options included the application of ultrafiltration for recovery of the coagulant from the sludge. The treatment performance and whole life cost (WLC) of the various recovered coagulant (RC) configurations have been considered in relation to fresh ferric sulphate (FFS). Pre-treatment of the sludge with acid followed by removal of organic and particulate contaminants using a 2kD ultrafiltration membrane resulted in a reusable coagulant that closely matched the performance FFS. Unacidified RC showed 53% of the phosphorus removal efficiency of FFS, at a dose of 20 mg/L as Fe and a contact time of 90 min. A longer contact time of 8 h improved performance to 85% of FFS. P removal at the shorter contact time improved to 88% relative to FFS by pre-acidifying the sludge to pH 2, using an acid molar ratio of 5.2:1 mol H+:Fe. Analysis of the removal of P showed that rapid phosphate precipitation accounted for >65% of removal with FFS. However, for the acidified RC a slower adsorption mechanism dominated; this was accelerated at a lower pH. A cost-benefit analysis showed that relative to dosing FFS and disposing waterworks sludge to land, the 20 year WLC was halved by transporting acidified or unacidified sludge up to 80 km for reuse in wastewater treatment. A maximum inter-site distance was determined to be 240 km above the current disposal route at current prices. Further savings could be made if longer contact times were available to allow greater P removal with unacidified RC

Coagulant recovery and reuse for drinking water treatment

Coagulant recovery and reuse from waterworks sludge has the potential to significantly reduce waste disposal and chemicals usage for water treatment. Drinking water regulations demand purification of recovered coagulant before they can be safely reused, due to the risk of disinfection by-product precursors being recovered from waterworks sludge alongside coagulant metals. While several full-scale separation technologies have proven effective for coagulant purification, none have matched virgin coagulant treatment performance. This study examines the individual and successive separation performance of several novel and existing ferric coagulant recovery purification technologies to attain virgin coagulant purity levels. The new suggested approach of alkali extraction of dissolved organic compounds (DOC) from waterworks sludge prior to acidic solubilisation of ferric coagulants provided the same 14:1 selectivity ratio (874 mg/L Fe vs. 61 mg/L DOC) to the more established size separation using ultrafiltration (1285 mg/L Fe vs. 91 mg/L DOC). Cation exchange Donnan membranes were also examined: while highly selective (2555 mg/L Fe vs. 29 mg/L DOC, 88:1 selectivity), the low pH of the recovered ferric solution impaired subsequent treatment performance. The application of powdered activated carbon (PAC) to ultrafiltration or alkali pre-treated sludge, dosed at 80 mg/mg DOC, reduced recovered ferric DOC contamination to <1 mg/L but in practice, this option would incur significant costs. The treatment performance of the purified recovered coagulants was compared to that of virgin reagent with reference to key water quality parameters. Several PAC-polished recovered coagulants provided the same or improved DOC and turbidity removal as virgin coagulant, as well as demonstrating the potential to reduce disinfection byproducts and regulated metals to levels comparable to that attained from virgin material

Heart failure nursing in Australia: Challenges, strengths, and opportunities

Australia has a land mass similar to the United States of America, supporting a population of just over 20 million, which is distributed predominantly across the coastal perimeter. The Australian society is rich in cultural diversity fostered by decades of migration. Both these factors present challenges for health care. First, because resources are scare in rural and remote regions, health outcomes are poorer in these regions, especially among indigenous populations. Second, the cultural diversity of Australians is a challenge to providing evidence-based treatment recommendations. In Australia, in parallel with international trends, there is a strong association between socioeconomic status, chronic conditions, and health outcomes

eHealth and the Internet of Things

To respond to an ageing population, eHealth strategies offer significant opportunities in achieving a balanced and sustainable healthcare infrastructure. Advances in technology both at the sensor and device levels and in respect of information technology have opened up other possibilities and options. Of significance among these is what is increasingly referred to as the Internet of Things, the interconnection of physical devices to an information infrastructure. The paper therefore sets out to position the Internet of Things at the core of future developments in eHealt

Reuse of recovered coagulants in water treatment: An investigation on the effect coagulant purity has on treatment performance

Coagulant recovery offers many potential benefits to water treatment, by reducing chemical demand and waste production. The key obstacle to successful implementation is achieving the same levels of treatment quality and process economics as commercial coagulants. This study has evaluated the selectivity of pressure-filtration in the role of a low-cost coagulant recovery technology from waterworks sludge. The treatment performance of the purified recovered coagulant was directly compared to fresh and raw recovered coagulants. DOC and turbidity removal by recovered coagulants was close to that of commercial coagulants, indicating that coagulant can be successfully recovered and regenerated by acidifying waterworks sludge. However, performance was less consistent, with a much narrower optimum charge neutralisation window and 10–30% worse removal performance under optimum conditions. This inferior performance was particularly evident for recovered ferric coagulants. The impact of this was confirmed by measuring THM formation potential and residual metals concentrations, showing 30–300% higher THMFPs when recovered coagulants were used. This study confirms that pressure-filtration can be operated on an economically viable basis, in terms of mass flux and fouling. However, the selectivity currently falls short of the purity required for potable treatment, due to incomplete rejection of sludge contaminants