Search results for "libration"
showing 10 items of 901 documents
Non-Matrix-Matched Calibration for the Multi-Element Analysis of Geological and Environmental Samples Using 200 nm Femtosecond LA-ICP-MS: A Compariso…
2014
LA-ICP-MS is one of the most promising techniques for in situ analysis of geological and environmental samples. However, there are some limitations with respect to measurement accuracy, in particular for volatile and siderophile/chalcophile elements, when using non-matrix-matched calibration. We therefore investigated matrix-related effects with a new 200 nm femtosecond (fs) laser ablation system (NWRFemto200) using reference materials with different matrices and spot sizes from 10 to 55 μm. We also performed similar experiments with two nanosecond (ns) lasers, a 193 nm excimer (ESI NWR 193) and a 213 nm Nd:YAG (NWR UP-213) laser. The ion intensity of the 200 nm fs laser ablation was much l…
The problem of spatial homogeneity in an LCoS projector
2019
Abstract Video projectors allow interesting applications in vision sciences since they provide a large projection area. We have colorimetrically characterized a LCoS projector using a mathematical model requiring additivity and constancy of the primaries -a sigmoid function in our case. Significant differences in chromaticity in the CIELAB space, but not in lightness, were found between the center and the corners of the screen. The lack of spatial homogeneity led us to estimate the parameters of the model as a function of spatial position, using different strategies. The best result was obtained by interpolating the values of the parameters of the model determined from experimental measurem…
Molecular phylogeny of the Notostraca
2012
Abstract We used a combined analysis of one nuclear (28S rDNA) and three mitochondrial markers (COI, 12S rDNA, 16S rDNA) to infer the molecular phylogeny of the Notostraca, represented by samples from the six continents that are inhabited by this group of branchiopod crustaceans. Our results confirm the monophyly of both extant notostracan genera Triops and Lepidurus with good support in model based and maximum parsimony analyses. We used branchiopod fossils as a calibration to infer divergence times among notostracan lineages and accounted for rate heterogeneity among lineages by applying relaxed-clock models. Our divergence date estimates indicate an initial diversification into the gener…
Estimation of the size of liposomes by modified HDC
1991
Internal calibration in modified hydrodynamic chromatography has been realized by the approach of Prieve and Hoysan, i.e. the use of polystyrene monodisperse latexes to evaluate the equivalent capillary radius, R. The value obtained has been used to estimate the average sizes of a variety of liposome samples from egg yolk lecithin.
Measurement of the Generalized Polarizabilities of the Proton at Intermediate $Q^2$
2021
Background: Generalized polarizabilities (GPs) are important observables to describe the nucleon structure, and measurements of these observables are still scarce. Purpose: This paper presents details of a virtual Compton scattering (VCS) experiment, performed at the A1 setup at the Mainz Microtron by studying the $e p \to e p \gamma$ reaction. The article focuses on selected aspects of the analysis. Method: The experiment extracted the $P_{LL} -P_{TT} / \epsilon$ and $P_{LT}$ structure functions, as well as the electric and magnetic GPs of the proton, at three new values of the four-momentum transfer squared $Q^2$: 0.10, 0.20 and 0.45 GeV$^2$. Results: We emphasize the importance of the ca…
Initial results of NEXT-DEMO, a large-scale prototype of the NEXT-100 experiment
2013
NEXT-DEMO is a large-scale prototype of the NEXT-100 detector, an electroluminescent time projection chamber that will search for the neutrinoless double beta decay of Xe-136 using 100-150 kg of enriched xenon gas. NEXT-DEMO was built to prove the expected performance of NEXT-100, namely, energy resolution better than 1% FWHM at 2.5MeV and event topological reconstruction. In this paper we describe the prototype and its initial results. A resolution of 1.75% FWHM at 511 keV (which extrapolates to 0.8% FWHM at 2.5 MeV) was obtained at 10 bar pressure using a gamma-ray calibration source. Also, a basic study of the event topology along the longitudinal coordinate is presented, proving that it…
Precise measurement of 1H 90° pulse in solid-state NMR spectroscopy for complex and heterogeneous molecular systems
2007
The 90 degrees pulse calibration is essential in NMR spectroscopy to prevent artefacts in the liquid state or to enhance cross-polarization efficiency in the solid state. We verified pulse-angle (PA) errors due to circuit impedances in solid-state NMR and suggested a possible solution to prevent the inconvenience of PA errors. The classic pulse sequences used to calibrate (1)H 90 degrees pulse lengths by direct detection of protons or by cross-polarization were modified in order to replace single (1)H pulses with (1)H pulse trains. Pulse trains were found to decrease the effect of PA imperfections in the calibration of basic pulses (i.e. 90 degrees and 180 degrees ) for a number of organic …
Inferring heterozygosity from ancient and low coverage genomes
2016
Abstract While genetic diversity can be quantified accurately from high coverage sequencing data, it is often desirable to obtain such estimates from data with low coverage, either to save costs or because of low DNA quality, as is observed for ancient samples. Here, we introduce a method to accurately infer heterozygosity probabilistically from sequences with average coverage <1× of a single individual. The method relaxes the infinite sites assumption of previous methods, does not require a reference sequence, except for the initial alignment of the sequencing data, and takes into account both variable sequencing errors and potential postmortem damage. It is thus also applicable to …
A Tunable Digital Ishihara Plate for Pre-School Aged Children
2016
Colors play a fundamental role for children, both in the everyday life and in education. They recognize the surrounding world, and play games making a large use of colors. They learn letters and numbers by means of colors. As a consequence, early diagnosis of color blindness is an crucial to support an individual affected by this visual perception alteration at the initial phase of his/her life. The diagnosis of red-green color deficiencies (protanopia or deuteranopia) is commonly accomplished by means of the Ishihara test, which consists of plates showing dots with different sizes where some of them compose numbers within a gamut of colors while the ones composing the background have diffe…
Choice of CTO scores to predict procedural success in clinical practice. A comparison of 4 different CTO PCI scores in a comprehensive national regis…
2021
Background We aimed to compare the performance of the recent CASTLE score to J-CTO, CL and PROGRESS CTO scores in a comprehensive database of percutaneous coronary intervention of chronic total occlusion procedures. Methods Scores were calculated using raw data from 1,342 chronic total occlusion procedures included in REBECO Registry that includes learning and expert operators. Calibration, discrimination and reclassification were evaluated and compared. Results Mean score values were: CASTLE 1.60±1.10, J-CTO 2.15±1.24, PROGRESS 1.68±0.94 and CL 2.52±1.52 points. The overall percutaneous coronary intervention success rate was 77.8%. Calibration was good for CASTLE and CL, but not for J-CTO…