1,595 research outputs found

    Increasing the representation accuracy of quantum simulations of chemistry without extra quantum resources

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    Proposals for near-term experiments in quantum chemistry on quantum computers leverage the ability to target a subset of degrees of freedom containing the essential quantum behavior, sometimes called the active space. This approximation allows one to treat more difficult problems using fewer qubits and lower gate depths than would otherwise be possible. However, while this approximation captures many important qualitative features, it may leave the results wanting in terms of absolute accuracy (basis error) of the representation. In traditional approaches, increasing this accuracy requires increasing the number of qubits and an appropriate increase in circuit depth as well. Here we introduce a technique requiring no additional qubits or circuit depth that is able to remove much of this approximation in favor of additional measurements. The technique is constructed and analyzed theoretically, and some numerical proof of concept calculations are shown. As an example, we show how to achieve the accuracy of a 20 qubit representation using only 4 qubits and a modest number of additional measurements for a simple hydrogen molecule. We close with an outlook on the impact this technique may have on both near-term and fault-tolerant quantum simulations

    UK National Audit of Early Syphilis Management. Clinics audit: screening for and management of early syphilis

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    Data were provided by 131 clinics, and 56% of cases were managed in clinics in the London regions in 2003. Three clinics (2%) do not routinely screen new patients for syphilis, and 28 clinics (21%) do not routinely screen ‘rebook’ patients who have had a new partner. More than 80% of clinics routinely conduct cardiovascular and neurological examinations, although chest radiography is only performed by 50% of clinics and lumbar puncture by 13%. Only 19 (14%) clinics indicated not routinely using the recommended procaine penicillin G (PPG) regimen or one- or two-dose benzathine penicillin G (BPG) regimens for early syphilis, with 57% providing two doses of BPG 2.4 g, 40% providing PPG 750 mg for 10 days, and 15% providing one dose of BPG 2.4 g. Only seven clinics (5%) indicated that they provided treatment for early syphilis with PPG that is inferior to that recommended in the national guidelines. Only 18 clinics specified using the recommended dose and duration (or in excess of this) of PPG for neurosyphilis for cases with HIV infection. Provision for management of severe penicillin reaction is good, although few patients are desensitized. All clinics report that contact tracing for early syphilis is provided, and is mainly the responsibility of health advisers. Compared with auditing outcomes, audit of management policies overestimated performance in contact tracing and provision of dark ground microscopy

    UK National Audit of Early Syphilis Management. Case notes audit: diagnosis and treatment

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    A national audit of 781 early syphilis cases presenting during 2002–03 in UK genitourinary medicine clinics was conducted in late 2004, organized through the Regional Audit Groups. Data were aggregated by region and National Health Service trust, allowing practice to be compared between regions, between trusts within regions, as well as to national averages and the UK National Guidelines. An enzyme immunoassay was used to diagnose 695 (89%) cases (regional range 18–100%). Use of a non-treponemal test was not recorded for 44 (6%) cases. Dark ground microscopy was used in the diagnosis of only 80 (29%) primary cases. Uptake of HIV testing was 77% (range 69–94%). Nationally, 527 (67%) treatments were parenteral, with almost equal use of benzathine penicillin G for 262 (50%, range 0–97%) cases and procaine penicillin G (PPG) for 260 cases (49%, range 3–100%). There were 14 (5%) treatments with less than the recommended 750 mg dose of PPG. One hundred and five (40%) PPG treatments were with greater than 750 mg and/or for longer than 10 days of which 76 (72%) were for early latent syphilis and/or cases with HIV infection. One hundred and ninety two (86%, range 0–100%) of all oral treatments were with doxycycline. The recommended regimen of 100 mg doxycycline twice daily for 14 days was used for 104 (53%) cases; the other 91 (47%) treatments were with a variety of regimens, mainly treatments with larger doses and/or longer treatment intervals and some combination treatments. Fourteen (2%) cases were not treated; treatment was not reported for seven (0.9%) and not known for 10 (1.3%) cases, who were treated at other centres

    The worldwide costs of marine protected areas

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    Declines in marine harvests, wildlife, and habitats have prompted calls at both the 2002 World Summit on Sustainable Development and the 2003 World Parks Congress for the establishment of a global system of marine protected areas (MPAs). MPAs that restrict fishing and other human activities conserve habitats and populations and, by exporting biomass, may sustain or increase yields of nearby fisheries. Here we provide an estimate of the costs of a global MPA network, based on a survey of the running costs of 83 MPAs worldwide. Annual running costs per unit area spanned six orders of magnitude, and were higher in MPAs that were smaller, closer to coasts, and in high-cost, developed countries. Models extrapolating these findings suggest that a global MPA network meeting the World Parks Congress target of conserving 20–30% of the world’s seas might cost between 5billionand5 billion and 19 billion annually to run and would probably create around one million jobs. Although substantial, gross network costs are less than current government expenditures on harmful subsidies to industrial fisheries. They also ignore potential private gains from improved fisheries and tourism and are dwarfed by likely social gains from increasing the sustainability of fisheries and securing vital ecosystem services

    A Systematic Review of the Acute Effects of Exercise on Immune and Inflammatory Indices in Untrained Adults

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    BACKGROUND: Cardiovascular disease (CVD) is the leading cause of global mortality. Although the incidence may be reduced with regular exercise, the health benefits of a single bout of exercise on selected CVD risk factors are not well understood. The primary objective of this review is to consider the transient effects of exercise on immune (neutrophil count) and inflammatory (interleukin-6 [IL-6], C-reactive protein [CRP]) markers in untrained adults. METHODS: MEDLINE, EMBASE, CINAHL, Sports Discus and Cochrane were searched for relevant studies published from January 1946 to May 2013. Randomised controlled or crossover studies which measured any of these parameters in untrained but otherwise healthy participants in the 48 h following about of exercise, less than 1 h in duration were included. RESULTS: Ten studies met the inclusion criteria. The results indicate a single bout of aerobic or resistance exercise of moderate to high intensity promotes an increase in IL-6 (145 %) and neutrophil counts (51 %). It appears that 30–60 min of moderate to high intensity exercise is necessary to elicit such changes although variables such as the mode, intensity and pattern of exercise also affect the response. The acute response of CRP within the included studies is equivocal. CONCLUSIONS: Although responses to CRP are inconsistent, a single bout of exercise can increase the activity of both circulating IL-6 and neutrophil counts in untrained adults. These immune and inflammatory responses to a single bout of exercise may be linked to a range of health benefits

    The effect of farming system on dairy cow cleanliness in the UK and implications to udder health

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    The cleanliness of dairy cows was assessed using a 20 point hygiene score system at different times in the year on 14 organic and 14 conventional farms in the UK. Overall, cows were dirtier during winter housing compared to summer grazing. Farming system had no effect on cow cleanliness when cows were at grass, but when housed in the winter, organic cows were more likely to be cleaner. There was a link between cow hygiene scores and milk hygiene, with herds having lower bulk tank somatic cell counts (BTSCC) tending to have cleaner cows. This relationship was strongest for the organic herds. There was no significant link between hygiene score and Bactoscan (BS) count or mastitis incidence

    An Optimal UAV Deployment Algorithm for Bridging Communication

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    This is the author accepted manuscript. The final version is available from IEEE via the DOI in this record.In recent years, Unmanned Aerial Vehicles (UAVs) have attracted the attention of both the military and civilians because of their deployment in situations where part of the communication infrastructure is destroyed due to bomb blast, earthquake, flood, military operations or landslides. Also UAVs can be used in operations such as search and rescue, surveillance, forest fire monitoring, and border patrolling. Deployment of a UAV in a position where it can provide maximum coverage and high throughput is one of the vital problem that needs to be addressed. In this paper, we have proposed an optimal UAV deployment algorithm (OUDA) in order to bridge communication between two static nodes on the ground. In the proposed algorithm the UAV deploys to a position where it can provide the best communication facilities to both the nodes based on the received signal strength (RSS), and distance between nodes and UAV. Simulation results showed that the algorithm provides maximum throughput and low bit error rate (BER) once the UAV is fixed to an optimal position

    Stable Gene Targeting in Human Cells Using Single-Strand Oligonucleotides with Modified Bases

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    Recent advances allow multiplexed genome engineering in E. coli, employing easily designed oligonucleotides to edit multiple loci simultaneously. A similar technology in human cells would greatly expedite functional genomics, both by enhancing our ability to test how individual variants such as single nucleotide polymorphisms (SNPs) are related to specific phenotypes, and potentially allowing simultaneous mutation of multiple loci. However, oligo-mediated targeting of human cells is currently limited by low targeting efficiencies and low survival of modified cells. Using a HeLa-based EGFP-rescue reporter system we show that use of modified base analogs can increase targeting efficiency, in part by avoiding the mismatch repair machinery. We investigate the effects of oligonucleotide toxicity and find a strong correlation between the number of phosphorothioate bonds and toxicity. Stably EGFP-corrected cells were generated at a frequency of \sim0.05% with an optimized oligonucleotide design combining modified bases and reduced number of phosphorothioate bonds. We provide evidence from comparative RNA-seq analysis suggesting cellular immunity induced by the oligonucleotides might contribute to the low viability of oligo-corrected cells. Further optimization of this method should allow rapid and scalable genome engineering in human cells
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