606 research outputs found

    III-V semiconductor waveguides for photonic functionality at 780 nm

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    Photonic integrated circuits based on III-V semiconductor polarization-maintaining waveguides were designed and fabricated for the first time for application in a compact cold-atom gravimeter1,2 at an operational wavelength of 780 nm. Compared with optical fiber-based components, semiconductor waveguides achieve very compact guiding of optical signals for both passive functions, such as splitting and recombining, and for active functions, such as switching or modulation. Quantum sensors, which have enhanced sensitivity to a physical parameter as a result of their quantum nature, can be made from quantum gases of ultra-cold atoms. A cloud of ultra-cold atoms may start to exhibit quantum-mechanical properties when it is trapped and cooled using laser cooling in a magneto-optical trap, to reach milli-Kelvin temperatures. The work presented here focuses on the design and fabrication of optical devices for a quantum sensor to measure the acceleration of gravity precisely and accurately. In this case the cloud of ultra-cold atoms consists of rubidium (87Rb) atoms and the sensor exploits the hyperfine structure of the D1 transition, from an outer electronic state of 5 2S ½ to 5 2P3/2 which has an energy of 1.589 eV or 780.241 nm. The short wavelength of operation of the devices dictated stringent requirements on the Molecular Beam Epitaxy (MBE) and device fabrication in terms of anisotropy and smoothness of plasma etch processes, cross-wafer uniformities and alignment tolerances. Initial measurements of the optical loss of the polarization-maintaining waveguide, assuming Fresnel reflection losses only at the facets, suggested a loss of 8 dB cm-1, a loss coefficient, α, of 1.9 (±0.3) cm-1

    Cost-effectiveness modeling of abatacept versus other biologic agents in DMARDS and anti-TNF inadequate responders for the management of moderate to severe rheumatoid arthritis

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    To assess the cost-effectiveness of abatacept compared to different biologic treatment strategies for moderate to severe rheumatoid arthritis based on current medical practices in Canada. A model was constructed to assess the cost-effectiveness of various biologic treatments over a 2-year time horizon, using two effectiveness endpoints: "low disease activity state” (LDAS) and "remission”. Abatacept, as first biologic agent after an inadequate response to DMARDs, provides greater treatment success rate for achieving LDAS (29.4% versus 15.6%) and remission (14.8% versus 5.2%), and appears significantly more cost-effective compared to the sequential use of anti-TNF agents (p < 0.001). Abatacept, as second biologic agent after an inadequate response to one anti-TNF agent, provides greater treatment success rate for achieving LDAS (17.1% versus 10.2%) and remission (7.4% versus 3.9%) and appears significantly more cost-effective compared to the sequential use of anti-TNF agents (p < 0.001). Abatacept is a cost-effective strategy in patients with an inadequate response to DMARDs or to one anti-TNF agen

    Effects of transcutaneous electric acupoint stimulation on drug use and responses to cue-induced craving: a pilot study

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    Background: Transcutaneous electric acupoint stimulation (TEAS) avoids the use of needles, and instead delivers a mild electric current at traditional acupoints. This technique has been used for treating heroin addiction, but has not been systematically tested for other drugs of abuse. This study aims to investigate the effects of TEAS on drug addiction. Methods: Volunteers who were either cocaine-dependent (n = 9) or cannabis-dependent (n = 11) but were not seeking treatment for their dependence participated in a within-subject, single-blind study. Treatment consisted of twice daily 30-minute sessions of TEAS or sham stimulation for 3.5 days. The active TEAS levels were individually adjusted to produce a distinct twitching response in the fingers, while the sham stimulation involved 2 minutes of stimulation at threshold levels followed by 28 minutes of stimulation below the detection levels. The participants recorded their drug use and drug cravings daily. At 1 hour after the last morning session of TEAS or sham stimulation, a cue-induced craving EEG evaluation was conducted. Event-related P300 potentials (ERPs) were recorded, sorted, and analyzed for specific image types (neutral objects, non-drug-related arousing images, or drug-related images). Results: TEAS treatment did not significantly reduce the drug use or drug cravings, or significantly alter the ERP peak voltage or latency to peak response. However, the TEAS treatment did significantly modulate several self-reported measures of mood and anxiety. Conclusion: The results of this pilot study with a limited sample size suggest that the acupoint stimulation techniques and protocol used in this trial alone do not significantly reduce cravings for or use of cocaine or cannabis. The findings that TEAS modulates mood and anxiety suggest that TEAS could be used as an adjunct in a multimodal therapy program to treat cocaine and cannabis dependence if confirmed in a full randomized controlled clinical trial

    Recommendation report for the implementation of research data management policy and for a sustainable research data management service at the University of Exeter

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    This is the Open Access and Research Data Management Policy Task and Finish Group's recommendation report for the implementation of research data management policy and a sustainable research data management service at the University of Exeter.JIS

    Linear tracks and restricted temperature ranges characterise penguin foraging pathways

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    Marine predators are thought to follow sophisticated scale-dependent search strategies when seeking patchy and unpredictable prey. However, fine-scale information about these strategies has hitherto been difficult to obtain for diving predators that often remain at the sea surface for only limited periods of time. Using ARGOS telemetry and novel, low-powered, archival GPS, we followed the fine-scale at-sea behaviour of king penguins breeding on South Georgia. Results revealed that foraging pathways were generally linear, except at the finest scale, where movements probably reflected either fine-scale searching behaviour, or fine-scale random movements associated with having found prey. King penguins focused 45% of their foraging effort in waters with a specific surface temperature (5.0 to 5.5 degrees C) - an environmental cue potentially important in helping them locate prey, thereby reducing their need to expend energy in area-restricted search patterns. Within these waters, penguins slowed down and increased their dive effort and degree of meandering. First Passage Time analysis revealed that penguins focused much of their effort at local scales, generally in areas with a radius of 2 km. In these areas, penguins dived marginally deeper and targeted waters that, were significantly warmer at the bottom of their dives. Such information about fine-scale foraging behaviour will help increase our understanding of the environmental correlates that characterise areas where marine predators exploit their prey. The scale of these behavioural processes is better resolved using the fine-scale temporal and spatial resolution of GPS tracking data

    Leaving no-one behind? Informal economies, economic inclusion, and Islamic extremism in Nigeria

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    This article examines how the Post-2015 commitment to economic inclusion affects informal economic actors in developing countries. It highlights the selective dynamics of inclusive market models which generate new processes of exclusion in which the most vulnerable continue to be left behind. The case of Nigeria reveals how inclusive market initiatives reinforce parallel processes of informalization, poverty and Islamic extremism in the north of the country. Fieldwork in northern Nigeria shows that inclusive initiatives are intensifying competitive struggles within the informal economy in which stronger actors are crowding out poorer, less educated and migrant actors, exacerbating disaffection and vulnerability to radicalization

    Real-time In-Situ Passive Acoustic Array Beamforming from the AutoNaut Wave-Propelled Uncrewed Surface Vessel

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    This article presents the first demonstration of beamforming, detection, and bearing estimation of an underwater acoustic source from an eight-element thin line hydrophone array towed behind the AutoNaut wave-propelled uncrewed surface vessel. This has been achieved in situ and in real time during an experimental sea trial off the coast of Plymouth, U.K. A controlled acoustic source was towed from a support vessel while emitting seven tonals with frequencies between 480&amp;#x2013;1630&amp;#x00A0;Hz and source levels between 93&amp;#x2013;126&amp;#x00A0;dB. This allowed the detection performance of the array to be assessed and demonstrated for an acoustic source with known bearing and range. In postprocessing, the shape of the array was estimated using a cubic spline model, exploiting measurements from pressure and three-axis compass sensors integrated at each end of the array. The beamforming was repeated using the estimated array shape to infer the hydrophone positions, which resulted in a median improvement of 0.38&amp;#x00A0;dB and maximum of 5.8&amp;#x00A0;dB in the MUSIC beamforming output, and a potential reduction in the left/right bearing estimation ambiguities. The outcomes of this work demonstrate that the AutoNaut is an effective platform for towed array passive acoustic monitoring.</p

    21st Century Cures Act: Patient Perceptions on Open Information Sharing in Vermont Primary Care Clinics

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    Introduction: The 21st Century Cures Act federally mandated the release of progress notes, laboratory test results, and radiology/pathology reports to the patient’s electronic health record (EHR) portal. This study investigates patient perspectives on shared notes and addresses provider concerns about patient uptake due to potential factors like worry, confusion, and distress at the University of Vermont Medical Center. Materials and Methods: An electronic cross-sectional survey was designed and distributed to 7,240 eligible patients, adults who logged into MyChart on Epic and had an outpatient/telemedical visit at either the Colchester Family Medicine and South Burlington Primary Care locations in Vermont within one year prior to the study. Results: The survey response rate was 4.6%. Of the respondents, 90% agreed that the use of shared notes is a good idea, 76% found accessing notes easy, and 2% felt more worried about their health because of shared notes. 89%, 85%, and 82% of respondents found visit notes important for understanding their health, remembering their care plan, and feeling in control of their care, respectively. Conclusions: Based on this survey, provider concerns about patient stress may be overstated, as patients appear to benefit from shared notes through increased engagement with their health, communication with providers, and adherence to care plans
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