317 research outputs found
Anonymity for practical quantum networks
Quantum communication networks have the potential to revolutionise
information and communication technologies. Here we are interested in a
fundamental property and formidable challenge for any communication network,
that of guaranteeing the anonymity of a sender and a receiver when a message is
transmitted through the network, even in the presence of malicious parties. We
provide the first practical protocol for anonymous communication in realistic
quantum networks.Comment: 5 pages, published versio
O-band electrically injected quantum dot micro-ring lasers on on-axis (001) GaP/Si and V-groove Si
We report statistical comparisons of lasing characteristics in InAs quantum dot (QD) micro-rings directly grown on on-axis (001) GaP/Si and V-groove (001) Si substrates. CW thresholds as low as 3 mA and high temperature operation exceeding 80 degrees C were simultaneously achieved on the GaP/Si template template with an outer-ring radius of 50 mu m and a ring width of 4 mu m, while a sub-milliamp threshold of 0.6 mA was demonstrated on the V-groove Si template with a smaller cavity size of 5-mu m outer-ring radius and 3-mu m ring width. Evaluations were also made with devices fabricated simultaneously on native GaAs substrates over a significant sampling analysis. The overall assessment spotlights compelling insights in exploring the optimum epitaxial scheme for low-threshold lasing on industry standard Si substrates. (C) 2017 Optical Society of Americ
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The moral foundations of liberal modernity in Hegel's political philosophy
Hegel’s political philosophy is a defense of the modern liberal social and political world. Yet in defending the world of liberal modernity, Hegel departs from the arguments of the early modern political philosophers. Hegel argues that true freedom consists in doing duty for duty’s sake, not in the enjoyment of the goods of a limited private sphere free from others’ infringement. Hegel’s philosophy thus aims to defend morality and serious participation in a political community as ends in themselves, not as merely instrumental. But his philosophy is not a return to antiquity. Rather, Hegel defends morality and membership in the political community on new, distinctively modern grounds. Above all, he views as central to the characteristically modern worldview the elevation and liberation of the individual from the bonds of tradition and revelation. This dissertation articulates the distinctively new principles of the modern state as they appear in Hegel’s political philosophy and shows how those new principles change the character and content of modern man’s duties, as well as how those principles bring new problems. Most important among these problems is the delicate balance between individual liberation and rational, universally valid, moral and political principles as they exist in the modern world and as they are articulated in Hegel’s own works. This dissertation shows how Hegel treats the new principles and problems of modernity, and how he understands them to animate and shape all facets of modern social and political life.Governmen
Improving the normalization of complex interventions: measure development based on normalization process theory (NoMAD): study protocol
<b>Background</b> Understanding implementation processes is key to ensuring that complex interventions in healthcare are taken up in practice and thus maximize intended benefits for service provision and (ultimately) care to patients. Normalization Process Theory (NPT) provides a framework for understanding how a new intervention becomes part of normal practice. This study aims to develop and validate simple generic tools derived from NPT, to be used to improve the implementation of complex healthcare interventions.<p></p>
<b>Objectives</b> The objectives of this study are to: develop a set of NPT-based measures and formatively evaluate their use for identifying implementation problems and monitoring progress; conduct preliminary evaluation of these measures across a range of interventions and contexts, and identify factors that affect this process; explore the utility of these measures for predicting outcomes; and develop an online users’ manual for the measures.<p></p>
<b>Methods</b> A combination of qualitative (workshops, item development, user feedback, cognitive interviews) and quantitative (survey) methods will be used to develop NPT measures, and test the utility of the measures in six healthcare intervention settings.<p></p>
<b>Discussion</b> The measures developed in the study will be available for use by those involved in planning, implementing, and evaluating complex interventions in healthcare and have the potential to enhance the chances of their implementation, leading to sustained changes in working practices
Genetic risk prediction of atrial fibrillation
Background—Atrial fibrillation (AF) has a substantial genetic basis. Identification of individuals at greatest AF risk could minimize the incidence of cardioembolic stroke.
Methods—To determine whether genetic data can stratify risk for development of AF, we examined associations between AF genetic risk scores and incident AF in five prospective studies comprising 18,919 individuals of European ancestry. We examined associations between AF genetic risk scores and ischemic stroke in a separate study of 509 ischemic stroke cases (202 cardioembolic [40%]) and 3,028 referents. Scores were based on 11 to 719 common variants (≥5%) associated with AF at P-values ranging from <1x10-3 to <1x10-8 in a prior independent genetic association study.
Results—Incident AF occurred in 1,032 (5.5%) individuals. AF genetic risk scores were associated with new-onset AF after adjusting for clinical risk factors. The pooled hazard ratio for incident AF for the highest versus lowest quartile of genetic risk scores ranged from 1.28 (719 variants; 95%CI, 1.13-1.46; P=1.5x10-4) to 1.67 (25 variants; 95%CI, 1.47-1.90; P=9.3x10-15). Discrimination of combined clinical and genetic risk scores varied across studies and scores (maximum C statistic, 0.629-0.811; maximum ΔC statistic from clinical score alone, 0.009-0.017). AF genetic risk was associated with stroke in age- and sex-adjusted models. For example, individuals in the highest versus lowest quartile of a 127-variant score had a 2.49-fold increased odds of cardioembolic stroke (95%CI, 1.39-4.58; P=2.7x10-3). The effect persisted after excluding individuals (n=70) with known AF (odds ratio, 2.25; 95%CI, 1.20-4.40; P=0.01).
Conclusions—Comprehensive AF genetic risk scores were associated with incident AF beyond associations for clinical AF risk factors, though offered small improvements in discrimination. AF genetic risk was also associated with cardioembolic stroke in age- and sex-adjusted analyses. Efforts are warranted to determine whether AF genetic risk may improve identification of subclinical AF or help distinguish between stroke mechanisms
Nightly treatment of primary insomnia with prolonged release melatonin for 6 months: a randomized placebo controlled trial on age and endogenous melatonin as predictors of efficacy and safety
<p>Background: Melatonin is extensively used in the USA in a non-regulated manner for sleep disorders. Prolonged release melatonin (PRM) is licensed in Europe and other countries for the short term treatment of primary insomnia in patients aged 55 years and over. However, a clear definition of the target patient population and well-controlled studies of long-term efficacy and safety are lacking. It is known that melatonin production declines with age. Some young insomnia patients also may have low melatonin levels. The study investigated whether older age or low melatonin excretion is a better predictor of response to PRM, whether the efficacy observed in short-term studies is sustained during continued treatment and the long term safety of such treatment.</p>
<p>Methods: Adult outpatients (791, aged 18-80 years) with primary insomnia, were treated with placebo (2 weeks) and then randomized, double-blind to 3 weeks with PRM or placebo nightly. PRM patients continued whereas placebo completers were re-randomized 1:1 to PRM or placebo for 26 weeks with 2 weeks of single-blind placebo run-out. Main outcome measures were sleep latency derived from a sleep diary, Pittsburgh Sleep Quality Index (PSQI), Quality of Life (World Health Organzaton-5) Clinical Global Impression of Improvement (CGI-I) and adverse effects and vital signs recorded at each visit.</p>
<p>Results: On the primary efficacy variable, sleep latency, the effects of PRM (3 weeks) in patients with low endogenous melatonin (6-sulphatoxymelatonin [6-SMT] ≤8 μg/night) regardless of age did not differ from the placebo, whereas PRM significantly reduced sleep latency compared to the placebo in elderly patients regardless of melatonin levels (-19.1 versus -1.7 min; P = 0.002). The effects on sleep latency and additional sleep and daytime parameters that improved with PRM were maintained or enhanced over the 6-month period with no signs of tolerance. Most adverse events were mild in severity with no clinically relevant differences between PRM and placebo for any safety outcome.</p>
<p>Conclusions: The results demonstrate short- and long-term efficacy and safety of PRM in elderly insomnia patients. Low melatonin production regardless of age is not useful in predicting responses to melatonin therapy in insomnia. The age cut-off for response warrants further investigation.</p>
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In Vitro Fermentation of NUTRIOSE® FB06, a wheat dextrin soluble fibre, in a continuous culture human colonic model system
Wheat dextrin soluble fibre may have metabolic and health benefits, potentially acting via mechanisms governed by the selective modulation of the human gut microbiota. Our aim was to examine the impact of wheat dextrin on the composition and metabolic activity of the gut microbiota. We used a validated in vitro three-stage continuous culture human colonic model (gut model) system comprised of vessels simulating anatomical regions of the human colon. To mimic human ingestion, 7 g of wheat dextrin (NUTRIOSE® FB06) was administered to three gut models, twice daily at 10.00 and 15.00, for a total of 18 days. Samples were collected and analysed for microbial composition and organic acid concentrations by 16S rRNA-based fluorescence in situ hybridisation and gas chromatography approaches, respectively. Wheat dextrin mediated a significant increase in total bacteria in vessels simulating the transverse and distal colon, and a significant increase in key butyrate-producing bacteria Clostridium cluster XIVa and Roseburia genus in all vessels of the gut model. The production of principal short-chain fatty acids, acetate, propionate and butyrate, which have been purported to have protective, trophic and metabolic host benefits, were increased. Specifically, wheat dextrin fermentation had a significant butyrogenic effect in all vessels of the gut model and significantly increased production of acetate (vessels 2 and 3) and propionate (vessel 3), simulating the transverse and distal regions of the human colon, respectively. In conclusion, wheat dextrin NUTRIOSE® FB06 is selectively fermented in vitro by Clostridium cluster XIVa and Roseburia genus and beneficially alters the metabolic profile of the human gut microbiota
The Diagnostic Potential of Fe Lines Applied to Protostellar Jets
We investigate the diagnostic capabilities of iron lines for tracing the physical conditions of shock-excited gas in jets driven by pre-main sequence stars. We have analyzed the 3000-25000 \uc5, X-shooter spectra of two jets driven by the pre-main sequence stars ESO-H\u3b1 574 and Par-Lup 3-4. Both spectra are very rich in [Fe II] lines over the whole spectral range; in addition, lines from [Fe III] are detected in the ESO-H\u3b1 574 spectrum. Non-local thermal equilibrium codes solving the equations of the statistical equilibrium along with codes for the ionization equilibrium are used to derive the gas excitation conditions of electron temperature and density and fractional ionization. An estimate of the iron gas-phase abundance is provided by comparing the iron lines emissivity with that of neutral oxygen at 6300 \uc5. The [Fe II] line analysis indicates that the jet driven by ESO-H\u3b1 574 is, on average, colder (T e 3c 9000 K), less dense (n e 3c 2
7 104 cm-3), and more ionized (x e 3c 0.7) than the Par-Lup 3-4 jet (T e 3c 13,000 K, n e 3c 6
7 104 cm-3, x e < 0.4), even if the existence of a higher density component (n e 3c 2
7 105 cm-3) is probed by the [Fe III] and [Fe II] ultra-violet lines. The physical conditions derived from the iron lines are compared with shock models suggesting that the shock at work in ESO-H\u3b1 574 is faster and likely more energetic than the Par-Lup 3-4 shock. This latter feature is confirmed by the high percentage of gas-phase iron measured in ESO-H\u3b1 574 (50%-60% of its solar abundance in comparison with less than 30% in Par-Lup 3-4), which testifies that the ESO-H\u3b1 574 shock is powerful enough to partially destroy the dust present inside the jet. This work demonstrates that a multiline Fe analysis can be effectively used to probe the excitation and ionization conditions of the gas in a jet without any assumption on ionic abundances. The main limitation on the diagnostics resides in the large uncertainties of the atomic data, which, however, can be overcome through a statistical approach involving many line
Wi-Fi Channel Saturation as a Mechanism to Improve Passive Capture of Bluetooth Through Channel Usage Restriction
Bluetooth is a short-range wireless technology that provides audio and data links between personal smartphones and playback devices, such as speakers, headsets and car entertainment systems. Since its introduction in 2001, security researchers have suggested that the protocol is weak, and prone to a variety of attacks against its authentication, link management and encryption schemes. Key researchers in the field have suggested that reliable passive sniffing of Bluetooth traffic would enable the practical application of a range of currently hypothesised attacks. Restricting Bluetooth's frequency hopping behaviour by manipulation of the available channels, in order to make brute force attacks more effective has been a frequently proposed avenue of future research from the literature. This paper has evaluated the proposed approach in a series of experiments using the software defined radio tools and custom hardware developed by the Ubertooth project. The work concludes that the mechanism suggested by previous researchers may not deliver the proposed improvements, but describes an as yet undocumented interaction between Bluetooth and Wi-Fi technologies which may provide a Denial of Service attack mechanism
Recruiting people with severe mental illness through community pharmacies:real-world experiences from a UK study
BACKGROUND: Proxy recruitment of patient participants through community pharmacies may be a valuable strategy to maximise participation. This paper focuses on the feasibility of such a recruitment strategy for research involving people who experience severe mental illness. METHODS: Fifty-three community pharmacies, including 50 'Research Ready' pharmacies, were asked to recruit people with severe mental illness for participation in research. Pharmacists were asked to provide participant information to anyone presenting a prescription meeting specific criteria. RESULTS: Thirteen recruitment sites (25%) (from 4 distinct organisations) were approved to recruit patient participants. Eighty-five percent (n = 11) failed to recruit any potential participants. CONCLUSIONS: Proxy recruitment of people with severe mental illness through community pharmacies was challenging with challenges in both pharmacy- and participant-recruitment. Further investigation into supporting community pharmacists' engagement with recruiting patients with SMI as research participants is required
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