54 research outputs found

    Foundations of uncertainty in evaluation of nominal properties

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    Measurement uncertainty is a key component of metrology but, as it is defined, it does not apply to nominal properties. The possibility to define, evaluate, and express the uncertainty in the examination of nominal properties is then a critical prerequisite for a harmonized treatment of nominal properties in metrology. The assumption at the basis of this paper is that examination uncertainty can be understood in analogy with and as a generalization of measurement uncertainty. To this aim a foundational framework is introduced, grounded on a generic concept of evaluation uncertainty that applies equally to quantitative and non-quantitative evaluations. Based on this, a concept of examination uncertainty is presented and some examples of mathematical functions of examination uncertainty are proposed

    Accurate hemodynamic response estimation by removal of stimulus-evoked superficial response in fNIRS signals

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    Objective. We address the problem of hemodynamic response (HR) estimation when task-evoked extra-cerebral components are present in functional near-infrared spectroscopy (fNIRS) signals. These components might bias the HR estimation; therefore, careful and accurate denoising of data is needed. Approach. We propose a dictionary-based algorithm to process each single event-related segment of the acquired signal for both long separation (LS) and short separation (SS) channels. Stimulus-evoked components and physiological noise are modeled by means of two distinct waveform dictionaries. For each segment, after removal of the physiological noise component in each channel, a template is employed to estimate stimulus-evoked responses in both channels. Then, the estimate from the SS channel is employed to correct the evoked superficial response and refine the HR estimate from the LS channel. Main results. Analysis of simulated, semi-simulated and real data shows that, by averaging single-segment estimates over multiple trials in an experiment, reliable results and improved accuracy compared to other methods can be obtained. The average estimation error of the proposed method for the semi-simulated data set is 34% for oxy-hemoglobin (HbO) and 78% for deoxy-hemoglobin (HbR), considering 40 trials. The proposed method outperforms the results of the methods proposed in the literature. While still far from the possibility of single-trial HR estimation, a significant reduction in the number of averaged trials can also be obtained. Significance. This work proves that dedicated dictionaries can be successfully employed to model all different components of fNIRS signals. We demonstrate the effectiveness of a specifically designed algorithm structure in dealing with a complex denoising problem, enhancing the possibilities of fNIRS-based HR analysis

    Revisiting the multiscaling hypothesis at medium timescales

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    Les lois d'invariance d'échelle décrivent l'absence d'une échelle de temps caractéristique particulière contrôlant un processus stochastique. Un consensus existe dans la littérature concernant un modèle du trafic qui serait monofractal Gaussien auto-similaire aux échelles de temps plus grandes qu'un délai aller-retour des segments du protocole de transport TCP. Dans cet article, nous donnons des indices qui laissent penser qu'un comportement multifractal pourrait être présent à ces échelles de temps. Nous présentons des résultats qui diffèrent de la littérature, et prétendons qu'un modèle multifractal stationnaire doit être envisagé pour modéliser le trafic aux échelles de temps typiquement plus grandes que quelques centaines de millisecondes

    Development and Performance of RFD Crab Cavity Prototypes for HL-LHC AUP

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    The US will be contributing to the HL-LHC upgrade at CERN with the fabrication and qualification of RFD crabbing cavities in the framework of the HL-LHC Accelerator Upgrade Project (AUP) managed by Fermilab. AUP received Critical Decision 3 (CD-3) approval by DOE in December 2020 launching the project into the production phase. The electro-magnetic design of the cavity was inherited from the LHC Accelerator Research Program (LARP) but needed to be revised to meet new project requirements and to prevent issues encountered during beam tests performed at CERN in the R&D phase. Two prototype cavities were manufactured in industry and cold tested. Challenges specific to the RFD cavity were the stringent interface tolerances, the pole symmetry, and the higher-order-mode impedance spectrum. Chemical processing and heat treatments were performed initially at FNAL/ANL and are now being transferred to industry for the production phase. HOM dampers are manufactured and validated by JLAB. A summary of cold test results with and without HOM dampers is presented.Comment: 21st International Conference on RF Superconductivity (SRF23

    Development and Performance of RFD Crab Cavity Prototypes for HL-LHC AUP

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    The US will be contributing to the HL-LHC upgrade at CERN with the fabrication and qualification of RFD crabbing cavities in the framework of the HL-LHC Accelerator Upgrade Project (AUP) managed by Fermilab. AUP received Critical Decision 3 (CD-3) approval by DOE in December 2020 launching the project into the production phase. The electro-magnetic design of the cavity was inherited from the LHC Accelerator Research Program (LARP) but needed to be revised to meet new project requirements and to prevent issues encountered during beam tests performed at CERN in the R&D phase. Two prototype cavities were manufactured in industry and cold tested. Challenges specific to the RFD cavity were the stringent interface tolerances, the pole symmetry and the higher-order-mode impedance spectrum. Chemical processing and heat treatments were performed initially at FNAL/ANL and are now being transferred to industry for the production phase. HOM dampers are manufactured and validated by JLAB. A summary of cold test results with and without HOM dampers is presented

    Association of kidney disease measures with risk of renal function worsening in patients with type 1 diabetes

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    Background: Albuminuria has been classically considered a marker of kidney damage progression in diabetic patients and it is routinely assessed to monitor kidney function. However, the role of a mild GFR reduction on the development of stage 653 CKD has been less explored in type 1 diabetes mellitus (T1DM) patients. Aim of the present study was to evaluate the prognostic role of kidney disease measures, namely albuminuria and reduced GFR, on the development of stage 653 CKD in a large cohort of patients affected by T1DM. Methods: A total of 4284 patients affected by T1DM followed-up at 76 diabetes centers participating to the Italian Association of Clinical Diabetologists (Associazione Medici Diabetologi, AMD) initiative constitutes the study population. Urinary albumin excretion (ACR) and estimated GFR (eGFR) were retrieved and analyzed. The incidence of stage 653 CKD (eGFR < 60 mL/min/1.73 m2) or eGFR reduction > 30% from baseline was evaluated. Results: The mean estimated GFR was 98 \ub1 17 mL/min/1.73m2 and the proportion of patients with albuminuria was 15.3% (n = 654) at baseline. About 8% (n = 337) of patients developed one of the two renal endpoints during the 4-year follow-up period. Age, albuminuria (micro or macro) and baseline eGFR < 90 ml/min/m2 were independent risk factors for stage 653 CKD and renal function worsening. When compared to patients with eGFR > 90 ml/min/1.73m2 and normoalbuminuria, those with albuminuria at baseline had a 1.69 greater risk of reaching stage 3 CKD, while patients with mild eGFR reduction (i.e. eGFR between 90 and 60 mL/min/1.73 m2) show a 3.81 greater risk that rose to 8.24 for those patients with albuminuria and mild eGFR reduction at baseline. Conclusions: Albuminuria and eGFR reduction represent independent risk factors for incident stage 653 CKD in T1DM patients. The simultaneous occurrence of reduced eGFR and albuminuria have a synergistic effect on renal function worsening

    Genomic ancestry estimation quantifies use of wild species in grape breeding

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    BACKGROUND: Grapes are one of the world’s most valuable crops and most are made into wine. Grapes belong to the genus Vitis, which includes over 60 inter-fertile species. The most common grape cultivars derive their entire ancestry from the species Vitis vinifera, but wild relatives have also been exploited to create hybrid cultivars, often with increased disease resistance. RESULTS: We evaluate the genetic ancestry of some of the most widely grown commercial hybrids from North America and Europe. Using genotyping-by-sequencing (GBS), we generated 2482 SNPs and 56 indels from 7 wild Vitis, 7 V. vinifera, and 64 hybrid cultivars. We used a principal component analysis (PCA) based ancestry estimation procedure and verified its accuracy with both empirical and simulated data. V. vinifera ancestry ranged from 11 % to 76 % across hybrids studied. Approximately one third (22/64) of the hybrids have ancestry estimates consistent with F1 hybridization: they derive half of their ancestry from wild Vitis and half from V. vinifera. CONCLUSIONS: Our results suggest that hybrid grape breeding is in its infancy. The distribution of V. vinifera ancestry across hybrids also suggests that backcrosses to wild Vitis species have been more frequent than backcrosses to V. vinifera during hybrid grape breeding. This pattern is unusual in crop breeding, as it is most common to repeatedly backcross to elite, or domesticated, germplasm. We anticipate our method can be extended to facilitate marker-assisted selection in order to introgress beneficial wild Vitis traits, while allowing for offspring with the highest V. vinifera content to be selected at the seedling stage. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12864-016-2834-8) contains supplementary material, which is available to authorized users

    Ten-year incidence of hypertension in a Swiss population-based sample Incidence of hypertension in Switzerland.

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    Few studies assessed incidence and determinants of hypertension. We assessed the incidence and determinants of hypertension in a cohort of healthy adults aged 35-75 years living in Lausanne, Switzerland. Baseline data were collected from 2003 to 2006. Follow-ups were conducted in 2009-2012 and 2014-2017. Incident hypertension, defined as a systolic BP ≥140 mm Hg or a diastolic BP ≥90 mm Hg or anti-hypertensive medication, was assessed at 1) second follow-up only; 2) first and/or second follow-up. After 10.9 years, incident hypertension was 26.8% (analysis 1, N = 3299) and 30.3% (analysis 2, N = 3728). After multivariate adjustment, the variables associated with increased hypertension incidence were male gender [incident-rate ratio (IRR) and (95% confidence interval)]: 1.20 (1.07-1.35) and 1.24 (1.13-1.37) for analyses 1 and 2, respectively; increasing age (p for trend < 0.001) and body mass index (p for trend < 0.001) and history of cardiovascular disease (CVD). Being physically active was negatively associated with incident hypertension: 0.88 (0.78-0.98) and 0.92 (0.83-1.01) for analyses 1 and 2, respectively. Except for male gender, these associations remained after adjusting for baseline BP levels, with incident rate ratios for physical activity of 0.86 (0.77-0.96) and 0.91 (0.83-0.99) for analyses 1 and 2, respectively. No association was found for education, alcohol consumption or smoking status. We conclude that over 10.9 years, between 1/4 and 1/3 of the Swiss population aged 35-75 developed hypertension. Male gender, history of CVD, increasing age and higher BMI increase the risk of hypertension, while being physically active reduces the risk

    Application of a phase measurement algorithm to digitizing oscilloscope characterization

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    A phase measurement algorithm based on Fourier analysis is presented in this paper. Its application to oscilloscope characterization is discussed showing how a simple measurement setup can be employed to accurately analyze phase response and trigger timing. Experimental results are reported both to support the accuracy analysis and to provide actual data in a few practical cases
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