5,472 research outputs found

    Report of AhG on Exploration in Wavelet Video Coding

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    The AHG on Exploration in Wavelet Video Coding [1] was established at the 73rd MPEG meeting in Poznan, Poland, with the following mandates: 1. To identify and describe new applications of wavelet video coding; 2. For such applications, define coding conditions and plan a performance comparison with other codecs; 3. Conduct the exploration experiments; 4. Maintain and validate the exploration reference software; 5. Maintain and edit the wavelet codec reference document. All discussions took place over the reflector, [email protected], i.e., ~ 100 emails have been exchanged. AhG meeting: Saturday October 24th, 14:30-18:30, Nice Acropolis AhG meeting agenda: 1.- review of conducted exploration experiments on wavelet video coding; 2.- review 74th ISO/MPEG meeting input documents of interest to this AhG; 3.- review this AhG mandates and prepare AhG report, includine recommendation

    Ultrathin silicon nanowires for optical and electrical nitrogen dioxide detection

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    The ever-stronger attention paid to enhancing safety in the workplace has led to novel sensor development and improvement. Despite the technological progress, nanostructured sensors are not being commercially transferred due to expensive and non-microelectronic compatible materials and processing approaches. In this paper, the realization of a cost-effective sensor based on ultrathin silicon nanowires (Si NWs) for the detection of nitrogen dioxide (NO2 ) is reported. A modification of the metal-assisted chemical etching method allows light-emitting silicon nanowires to be obtained through a fast, low-cost, and industrially compatible approach. NO2 is a well-known dangerous gas that, even with a small concentration of 3 ppm, represents a serious hazard for human health. We exploit the particular optical and electrical properties of these Si NWs to reveal low NO2 concentrations through their photoluminescence (PL) and resistance variations reaching 2 ppm of NO2 . Indeed, these Si NWs offer a fast response and reversibility with both electrical and optical transductions. Despite the macro contacts affecting the electrical transduction, the sensing performances are of high interest for further developments. These promising performances coupled with the scalable Si NW synthesis could unfold opportunities for smaller sized and better performing sensors reaching the market for environmental monitoring

    Comparing the performance of the novel FAMCAT algorithms and established case-finding criteria for familial hypercholesterolaemia in primary care

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    OBJECTIVE: Familial hypercholesterolaemia (FH) is a common inherited disorder causing premature coronary heart disease (CHD) and death. We have developed the novel Familial Hypercholesterolaemia Case Ascertainment Tool (FAMCAT 1) case-finding algorithm for application in primary care, to improve detection of FH. The performance of this algorithm was further improved by including personal history of premature CHD (FAMCAT 2 algorithm). This study has evaluated their performance, at 95% specificity, to detect genetically confirmed FH in the general population. We also compared these algorithms to established clinical case-finding criteria. METHODS: Prospective validation study, in 14 general practices, recruiting participants from the general adult population with cholesterol documented. For 260 participants with available health records, we determined possible FH cases based on FAMCAT thresholds, Dutch Lipid Clinic Network (DLCN) score, Simon-Broome criteria and recommended cholesterol thresholds (total cholesterol >9.0 mmol/L if ≄30 years or >7.5 mmol/L if <30 years), using clinical data from electronic and manual extraction of patient records and family history questionnaires. The reference standard was genetic testing. We examined detection rate (DR), sensitivity and specificity for each case-finding criteria. RESULTS: At 95% specificity, FAMCAT 1 had a DR of 27.8% (95% CI 12.5% to 50.9%) with sensitivity of 31.2% (95% CI 11.0% to 58.7%); while FAMCAT 2 had a DR of 45.8% (95% CI 27.9% to 64.9%) with sensitivity of 68.8% (95% CI 41.3% to 89.0%). DLCN score ≄6 points yielded a DR of 35.3% (95% CI 17.3% to 58.7%) and sensitivity of 37.5% (95% CI 15.2% to 64.6%). Using recommended cholesterol thresholds resulted in DR of 28.0% (95% CI 14.3% to 47.6%) with sensitivity of 43.8% (95% CI 19.8% to 70.1%). Simon-Broome criteria had lower DR 11.3% (95% CI 6.0% to 20.0%) and specificity 70.9% (95% CI 64.8% to 76.5%) but higher sensitivity of 56.3% (95% CI 29.9% to 80.2%). CONCLUSIONS: In primary care, in patients with cholesterol documented, FAMCAT 2 performs better than other case-finding criteria for detecting genetically confirmed FH, with no prior clinical review required for case finding. TRIAL REGISTRATION NUMBER: NCT03934320

    Potential of wickerhamomyces anomalus in glycerol valorization

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    Five-carbons polyalcohols, such as xylitol and arabitol, and microbial oils are important targets for biotechnological industries. Polyalcohols can find application as low-calories sweeteners and as building block in the synthesis of valuable compounds, while lipids are interesting for both biofuel and food industry. The osmophilic yeast Wickerhamomyces anomalus WC 1501 was preliminary known to produce arabitol from glycerol. Production kinetics were investigated in this study. Production was not growth-associated and occurred during a nitrogen-limited stationary phase, in presence of an excess of carbon source. Typical bioreactor batch cultures, carried out with 160 g/L glycerol, yielded 16.0 g/L arabitol in 160 h. A fed-batch process was developed, in which growth is carried out batchwise in a balanced medium containing 20 g/L glycerol, and arabitol production is induced at the entrance into the stationary phase with a pulse of concentrated glycerol to provide the remaining 140 g/L carbon source. At the end of the process 18.0 g/L arabitol were generated. Under these conditions, the yeast also accumulated intracellular triacylglycerols, with fatty acids of 16-18 carbons bearing 0 to 2 unsaturations, reaching up the 23% of biomass dry weight. Therefore, W. anomalus WC 1501 is a good candidate for the development of a fermentative process yielding arabitol and has potential also as oleaginous yeast for producing lipids, further improving the interest in this strain for glycerol biorefinery. The utilization of a fed-batch process allows to carry out distinct growth and production phases and thus allows the optimization of both phases separately, in order to achieve the highest concentration of catalytic biomass during growth and the maximum efficiency during production. This strain deserves further investigation to better exploit its biotechnological potential in the valorization of glycerol

    Approximately efficient two-sided combinatorial auctions

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    We develop and extend a line of recent work on the design of mechanisms for two-sided markets. e markets we consider consist of buyers and sellers of a number of items, and the aim of a mechanism is to improve the social welfare by arranging purchases and sales of the items. A mechanism is given prior distributions on the agents’ valuations of the items, but not the actual valuations; thus the aim is to maximise the expected social welfare over these distributions. As in previous work, we are interested in the worst-case ratio between the social welfare achieved by a truthful mechanism, and the best social welfare possible. Our main result is an incentive compatible and budget balanced constant-factor approximation mechanism in a setting where buyers have XOS valuations and sellers’ valuations are additive. This is the rst such approximation mechanism for a two-sided market setting where the agents have combinatorial valuation functions. To achieve this result, we introduce a more general kind of demand query that seems to be needed in this situation. In the simpler case that sellers have unit supply (each having just one item to sell), we give a new mechanism whose welfare guarantee improves on a recent one in the literature. We also introduce a more demanding version of the strong budget balance (SBB) criterion, aimed at ruling out certain “unnatural” transactions satised by SBB. We show that the stronger version is satised by our mechanisms

    Applications of Microscopy in the Paper Industry: Case Histories of the Mead Corporation

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    Microscopial application in the Mead Corporation are herein discussed: 1) defining proper starch cook for maintaining paper quality, 2) microbial degradation of paperboard used for beverage cartons, and 3) examination of high oxygen barrier plastic cups for hermetic seal and barrier construction. Visualization of the cooked starch by iodine staining and polarized light (PL) microscopy is a quick diagnostic aid to Mead mills. Scanning electron microscopy (SEM) and particularly PL proved useful in examining fiber biodegration by fungi on Coated Natural Kraft beverage cartons. Nomarski differential interference contrast (DIC), PL, and SEM aided in qualifying lid materials for Mead\u27s Crosscheck Food Packaging System, defining hermetic seals, and examining container construction. Further, DIC optics have enhanced the observation of possible abnormalities in container construction used on Cross-check over conventional Kohler optics and/or SEM. Integrative microscopy was thus a valuable technique in problem resolution for the defined applications

    Phase field approach to optimal packing problems and related Cheeger clusters

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    In a fixed domain of RN\Bbb{R}^N we study the asymptotic behaviour of optimal clusters associated to α\alpha-Cheeger constants and natural energies like the sum or maximum: we prove that, as the parameter α\alpha converges to the "critical" value (N−1N)+\Big (\frac{N-1}{N}\Big ) _+, optimal Cheeger clusters converge to solutions of different packing problems for balls, depending on the energy under consideration. As well, we propose an efficient phase field approach based on a multiphase Gamma convergence result of Modica-Mortola type, in order to compute α\alpha-Cheeger constants, optimal clusters and, as a consequence of the asymptotic result, optimal packings. Numerical experiments are carried over in two and three space dimensions
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