307 research outputs found

    A variable delay integrated receiver for differential phase-shift keying optical transmission systems

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    An integrated variable delay receiver for DPSK optical transmission systems is presented. The device is realized in silicon-on-insulator technology and can be used to detect DPSK signals at any bit-rates between 10 and 15 Gbit/s

    Material type influences the abundance but not richness of colonising organisms on marine structures

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    Urbanisation of coastal areas and growth in the blue economy drive the proliferation of artificial structures in marine environments. These structures support distinct ecological communities compared to natural hard substrates, potentially reflecting differences in the materials from which they are constructed. We undertook a meta-analysis of 46 studies to compare the effects of different material types (natural or eco-friendly vs. artificial) on the colonising biota on built structures. Neither the abundance nor richness of colonists displayed consistent patterns of difference between artificial and natural substrates or between eco-friendly and standard concrete. Instead, there were differences in the abundance of organisms (but not richness) between artificial and natural materials, that varied according to material type and by functional group. When compared to biogenic materials and rock, polymer and metal supported significantly lower abundances of total benthic species (in studies assessing sessile and mobile species together), sessile invertebrates and corals (in studies assessing these groups individually). In contrast, non-indigenous species were significantly more abundant on wood than metal. Concrete supported greater abundances of the general community, including habitat-forming species, compared to wood. Our results suggest that the ecological requirements of the biological community, alongside economic, logistic and engineering factors should be considered in material selection for multifunctional marine structures that deliver both engineering and ecological (enhanced abundance and diversity) benefits

    Varespladib and cardiovascular events in patients with an acute coronary syndrome: the VISTA-16 randomized clinical trial

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    IMPORTANCE: Secretory phospholipase A2(sPLA2) generates bioactive phospholipid products implicated in atherosclerosis. The sPLA2inhibitor varespladib has favorable effects on lipid and inflammatory markers; however, its effect on cardiovascular outcomes is unknown. OBJECTIVE: To determine the effects of sPLA2inhibition with varespladib on cardiovascular outcomes. DESIGN, SETTING, AND PARTICIPANTS: A double-blind, randomized, multicenter trial at 362 academic and community hospitals in Europe, Australia, New Zealand, India, and North America of 5145 patients randomized within 96 hours of presentation of an acute coronary syndrome (ACS) to either varespladib (n = 2572) or placebo (n = 2573) with enrollment between June 1, 2010, and March 7, 2012 (study termination on March 9, 2012). INTERVENTIONS: Participants were randomized to receive varespladib (500 mg) or placebo daily for 16 weeks, in addition to atorvastatin and other established therapies. MAIN OUTCOMES AND MEASURES: The primary efficacy measurewas a composite of cardiovascular mortality, nonfatal myocardial infarction (MI), nonfatal stroke, or unstable angina with evidence of ischemia requiring hospitalization at 16 weeks. Six-month survival status was also evaluated. RESULTS: At a prespecified interim analysis, including 212 primary end point events, the independent data and safety monitoring board recommended termination of the trial for futility and possible harm. The primary end point occurred in 136 patients (6.1%) treated with varespladib compared with 109 patients (5.1%) treated with placebo (hazard ratio [HR], 1.25; 95%CI, 0.97-1.61; log-rank P = .08). Varespladib was associated with a greater risk of MI (78 [3.4%] vs 47 [2.2%]; HR, 1.66; 95%CI, 1.16-2.39; log-rank P = .005). The composite secondary end point of cardiovascular mortality, MI, and stroke was observed in 107 patients (4.6%) in the varespladib group and 79 patients (3.8%) in the placebo group (HR, 1.36; 95% CI, 1.02-1.82; P = .04). CONCLUSIONS AND RELEVANCE: In patients with recent ACS, varespladib did not reduce the risk of recurrent cardiovascular events and significantly increased the risk of MI. The sPLA2inhibition with varespladib may be harmful and is not a useful strategy to reduce adverse cardiovascular outcomes after ACS. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01130246. Copyright 2014 American Medical Association. All rights reserved

    Three-dimensional solid-state qubit arrays with long-lived spin coherence

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    Three-dimensional arrays of silicon transistors increase the density of bits. Solid-state qubits are much larger so could benefit even more from using the third dimension given that useful fault-tolerant quantum computing will require at least 100,000 physical qubits and perhaps one billion. Here we use laser writing to create 3D arrays of nitrogen-vacancy centre (NVC) qubits in diamond. This would allow 5 million qubits inside a commercially available 4.5x4.5x0.5 mm diamond based on five nuclear qubits per NVC and allowing (10ÎŒm)3 per NVC to leave room for our laser-written electrical control. The spin coherence times we measure are an order of magnitude longer than previous laser-written qubits and at least as long as non-laser-written NVC. As well as NVC quantum computing, quantum communication and nanoscale sensing could benefit from the same platform. Our approach could also be extended to other qubits in diamond and silicon carbide

    The Risk of Virologic Failure Decreases with Duration of HIV Suppression, at Greater than 50% Adherence to Antiretroviral Therapy

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    Background: We hypothesized that the percent adherence to antiretroviral therapy necessary to maintain HIV suppression would decrease with longer duration of viral suppression. Methodology: Eligible participants were identified from the REACH cohort of marginally housed HIV infected adults in San Francisco. Adherence to antiretroviral therapy was measured through pill counts obtained at unannounced visits by research staff to each participant's usual place of residence. Marginal structural models and targeted maximum likelihood estimation methodologies were used to determine the effect of adherence to antiretroviral therapy on the probability of virologic failure during early and late viral suppression. Principal Findings: A total of 221 subjects were studied (median age 44.1 years; median CD4+ T cell nadir 206 cells/mm3). Most subjects were taking the following types of antiretroviral regimens: non-nucleoside reverse transcriptase inhibitor based (37%), ritonavir boosted protease inhibitor based (28%), or unboosted protease inhibitor based (25%). Comparing the probability of failure just after achieving suppression vs. after 12 consecutive months of suppression, there was a statistically significant decrease in the probability of virologic failure for each range of adherence proportions we considered, as long as adherence was greater than 50%. The estimated risk difference, comparing the probability of virologic failure after 1 month vs. after 12 months of continuous viral suppression was 0.47 (95% CI 0.23–0.63) at 50–74% adherence, 0.29 (CI 0.03–0.50) at 75–89% adherence, and 0.36 (CI 0.23–0.48) at 90–100% adherence. Conclusions: The risk of virologic failure for adherence greater than 50% declines with longer duration of continuous suppression. While high adherence is required to maximize the probability of durable viral suppression, the range of adherence capable of sustaining viral suppression is wider after prolonged periods of viral suppression

    Coastal greening of grey infrastructure: an update on the state-of-the-art

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    \ua9 2023 Emerald Publishing Limited: All rights reserved.In the marine environment, greening of grey infrastructure (GGI) is a rapidly growing field that attempts to encourage native marine life to colonize marine artificial structures to enhance biodiversity, thereby promoting ecosystem functioning and hence service provision. By designing multifunctional sea defences, breakwaters, port complexes and off-shore renewable energy installations, these structures can yield myriad environmental benefits, in particular, addressing UN SDG 14: Life below water. Whilst GGI has shown great promise and there is a growing evidence base, there remain many criticisms and knowledge gaps, and some feel that there is scope for GGI to be abused by developers to facilitate harmful development. Given the surge of research in this field in recent years, it is timely to review the literature to provide an update update on the state-of-the-art of the field in relation to the many criticisms and identify remaining knowledge gaps. Despite the rapid and significant advances made in this field, there is currently a lack of science and practice outside of academic sectors in the developed world, and there is a collective need for schemes that encourage intersectoral and transsectoral research, knowledge exchange, and capacity building to optimize GGI in the pursuit of contributing to sustainable development
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