189 research outputs found

    A low-energy rate-adaptive bit-interleaved passive optical network

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    Energy consumption of customer premises equipment (CPE) has become a serious issue in the new generations of time-division multiplexing passive optical networks, which operate at 10 Gb/s or higher. It is becoming a major factor in global network energy consumption, and it poses problems during emergencies when CPE is battery-operated. In this paper, a low-energy passive optical network (PON) that uses a novel bit-interleaving downstream protocol is proposed. The details about the network architecture, protocol, and the key enabling implementation aspects, including dynamic traffic interleaving, rate-adaptive descrambling of decimated traffic, and the design and implementation of a downsampling clock and data recovery circuit, are described. The proposed concept is shown to reduce the energy consumption for protocol processing by a factor of 30. A detailed analysis of the energy consumption in the CPE shows that the interleaving protocol reduces the total energy consumption of the CPE significantly in comparison to the standard 10 Gb/s PON CPE. Experimental results obtained from measurements on the implemented CPE prototype confirm that the CPE consumes significantly less energy than the standard 10 Gb/s PON CPE

    The preparation and properties of lanthanum-promoted nickel-alumina catalysts:Structure of the precipitates

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    Precursors of La-promoted Ni-alumina catalysts have been prepared by precipitation from their nitrate solutions at pH 7 using solutions of NH4HCO3, Na2CO3 or K2CO3. The preparation was carried out either by coprecipitation from a mixed salt solution or by sequential precipitation of Al3+, La3+ and Ni2+ in succession. In the absence of promoter, the precipitate with Ni/Al ratio of 2.5 is of the pyroaurite structure and has the composition Ni5Al2(OH)14CO3.4H2O. Two types of lanthanum-containing precipitate were made in which either extra La was added (Ni/Al kept constant at 2.5) or the proportion Ni/(Al+La) was kept constant at 2.5. The majority of these precipitates were single compounds which also had the pyroaurite structure. At high La contents, the series in which La is added gives separation of the compounds La2O(CO3)2 and LaONO3 in addition to the layer structure; with the series in which the La is substituted for Al, all the samples appeared to have the pyroaurite structure, even one in which no Al was present. The sequential precipitation route yields smaller crystallites than does coprecipitation. Materials precipitated with NH4HCO3 in all cases contained NH4NO3 while those precipitated with Na2CO3 gave inclusion of NaNO3. In both cases, the presence of the nitrates causes a decrease of crystallinity of the layer compound. Potassium is not included in the precipitate in any of the samples examined. A model is presented for the structure of the lanthanum-containing precipitates

    Diffusing Aviation Innovations in a Hospital in the Netherlands

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    Background: Many authors have advocated the diffusion of innovations from other high-risk industries into health care to improve safety. The aviation industry is comparable to health care because of its similarities in (a) the use of technology, (b) the requirement of highly specialized professional teams, and (c) the existence of risk and uncertainties. For almost 20 years, The Rotterdam Eye Hospital (Rotterdam, the Netherlands) has been engaged in diffusing several innovations adapted from aviation. Methods: A case-study methodology was used to assess the application of innovations in the hospital, with a focus on the context and the detailed mechanism for each innovation. Data on hospital performance outcomes were abstracted from the hospital information data management system, quality and safety reports, and the incident reporting system. Information on the innovations was obtained from a document search; observations; and semistructured, face-to-face interviews. Innovations: Aviation industry-based innovations diffused into patient care processes were as follows: patient planning and booking system, taxi service/valet parking, risk analysis (as applied to wrong-site surgery), time-out procedure (also for wrong-site surgery), Crew Resource Management training, and black box. Observations indicated that the innovations had a positive effect on quality and safety in the hospital: Waiting times were reduced, work processes became more standardized, the number of wrong-site surgeries decreased, and awareness of patient safety was heightened. Conclusion: A near-20-year experience with aviation-based innovation suggests that hospitals start with relatively simple innovations and use a systematic approach toward the goal of improving safety

    Potential Retinal Biomarkers in Alzheimer's Disease

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    Alzheimer’s disease (AD) represents a major diagnostic challenge, as early detection is crucial for effective intervention. This review examines the diagnostic challenges facing current AD evaluations and explores the emerging field of retinal alterations as early indicators. Recognizing the potential of the retina as a noninvasive window to the brain, we emphasize the importance of identifying retinal biomarkers in the early stages of AD. However, the examination of AD is not without its challenges, as the similarities shared with other retinal diseases introduce complexity in the search for AD-specific markers. In this review, we address the relevance of using the retina for the early diagnosis of AD and the complex challenges associated with the search for AD-specific retinal biomarkers. We provide a comprehensive overview of the current landscape and highlight avenues for progress in AD diagnosis by retinal examination

    Children with severe acute asthma admitted to Dutch PICUs: A changing landscape

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    The number of children requiring pediatric intensive care unit (PICU) admission for severe acute asthma (SAA) around the world has increased. Objectives: We investigated whether this trend in SAA PICU admissions is present in the Netherlands. Methods: A multicenter retrospective cohort study across all tertiary care PICUs in the Netherlands. Inclusion criteria were children (2-18 years) hospitalized for SAA between 2003 and 2013. Data included demographic data, asthma diagnosis, treatment, and mortality. Results: In the 11-year study period 590 children (660 admissions) were admitted to a PICU with a threefold increase in the number of admissions per year over time. The severity of SAA seemed unchanged, based on the first blood gas, length of stay and mortality rate (0.6%). More children received highflow nasal cannula (P<0.001) and fewer children needed invasive ventilation (P<0.001). In 58% of the patients the maximal intravenous (IV) salbutamol infusion rate during PICU admission was 1mcg/kg/min. However, the number of patients treated with IV salbutamol in the referring hospitals increased significantly over time (P=0.005). The proportion of steroid-naïve patients increased from 35% to 54% (P=0.004), with a significant increase in both age groups (2-4 years [P=0.026] and 5-17 years [P=0.036]). Conclusions: The number of children requiring PICU admission for SAA in the Netherlands has increased. We speculate that this threefold increase is explained by an increasing number of steroid-naïve children, in conjunction with a lowered threshold for PICU admission, possibly caused by earlier use of salbutamol IV in the referring hospitals

    Patient profiled data for treatment decision-making:valuable as an add-on to hepatitis C clinical guidelines?

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    Background and Aims: Systematic reviews and medical guidelines are widely used in clinical practice. However, these are often not up-to-date and focussed on the average patient. We therefore aimed to evaluate a guideline add-on, TherapySelector (TS), which is based on monthly updated data of all available high-quality studies, classified in specific patient profiles. Methods: We evaluated the TS for the treatment of hepatitis C (HCV) in an international cohort of patients treated with direct-acting antivirals between 2015 and 2020. The primary outcome was the number of patients receiving one of the two preferred treatment options of the HCV TS, based on the highest level of evidence, cure rate, absence of ribavirin-associated adverse effects, and treatment duration. Results: We enrolled 567 patients. The number of patients treated with one of the two preferred treatment options according to the HCV TS ranged between 27% (2015) and 60% (2020; p &lt; 0.001). Most of the patients received a regimen with a longer treatment-duration (up to 34%) and/or addition of ribavirin (up to 14%). The effect on the expected cure-rate was minimal (1–6% higher) when the first preferred TherapySelector option was given compared to the actual treatment.Conclusions: Medical decision-making can be optimised by a guideline add-on; in HCV its use appears to minimise adverse effects and cost. The use of such an add-on might have a greater impact in diseases with suboptimal cure-rates, high costs or adverse effects, for which treatment options rely on specific patient characteristics.</p
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