Search results for "Spectrum"
showing 10 items of 2043 documents
Surface plasmon interference excited by tightly focused laser beams
2007
International audience; We show that interfering surface plasmon polaritons can be excited with a focused laser beam at normal incidence to a plane metal film. No protrusions or holes are needed in this excitation scheme. Depending on the axial position of the focus, the intensity distribution on the metal surface is either dominated by interferences between counterpropagating plasmons or by a two-lobe pattern characteristic of localized surface plasmon excitation. Our experiments can be accurately explained by use of the angular spectrum representation and provide a simple means for locally exciting standing surface plasmon polaritons.
Gas sensors arrays (electronic noses) : a study about the speed/accuracy ratio
2000
Abstract New Fingerprint Mass Spectra (FMS) systems claim for a higher precision, a reduced analysis time, and a lower drift, compared with Gas Sensors Arrays ‘Electronic Noses’. We demonstrated in this study that metal oxide gas sensors may have highly improved performances for both accuracy and run time, when used in optimum conditions. The different noise components were quantified referring to popular words (equivalent of ethanol concentration) using the transfer function of the sensor. It was pointed out that sample surrounding greatly affects the noise level, and that the signal-to-noise ratio may be dramatically increased, reducing the distortion generally assessed between sensor and…
Phase-Noise and Amplitude-Noise Measurement of DACs and DDSs
2019
This article proposes a method for the measurement of Phase Noise (PN, or PM noise) and Amplitude Noise (AN, or AM noise) of Digital-to-Analog Converters (DAC) and Direct Digital Synthesizers (DDS) based on modulation-index amplification. The carrier is first reduced by a controlled amount (30-40 dB) by adding a reference signal of nearly equal amplitude and opposite in phase. Then, residual carrier and noise sidebands are amplified and sent to a conventional PN analyzer. The main virtues of our method are: (i) the noise specs of the PN analyzer are relaxed by a factor equal to the carrier suppression ratio; and, (ii) the capability to measure the AN using a PN analyzer, with no need for th…
Searches for anisotropies in the arrival directions of the highest energy cosmic rays detected by the Pierre Auger Observatory
2015
We analyze the distribution of arrival directions of ultra-high energy cosmic rays recorded at the Pierre Auger Observatory in 10 years of operation. The data set, about three times larger than that used in earlier studies, includes arrival directions with zenith angles up to $80^\circ$, thus covering from $-90^\circ$ to $+45^\circ$ in declination. After updating the fraction of events correlating with the active galactic nuclei (AGNs) in the V��ron-Cetty and V��ron catalog, we subject the arrival directions of the data with energies in excess of 40 EeV to different tests for anisotropy. We search for localized excess fluxes and for self-clustering of event directions at angular scales up t…
Effect of a Service-Learning Program on the Active Lifestyle of Children with Autism Spectrum Disorder: A Pilot Study
2020
Background: active lifestyles and Physical Activity (PA) are closely related to health. Healthy habits such as being physically active should be consolidated during childhood. Children with Autism Spectrum Disorders (ASD) present fewer opportunities to be involved in PA. For this reason, we conducted a Service-Learning (SL) program to enhance the possibility of participating ASD children enjoying PA sessions. The aim of this study was to analyze and describe the evolution in terms of the frequency and intensity of PA performed by ASD children who participated in the SL program. Methods: we used a quasi-experimental design. The sample was formed by 26 children with ASD (Experimental group: n…
Autisma iezīmes, agresivitāte un vecāku – bērnu mijiedarbība bērniem vecumā no 22 līdz 30 mēnešiem
2018
Pētījuma ietvaros tika apzinātas sakarības starp autiskā spektra iezīmēm, agresivitāti un audzināšanas pieejām vecāku-bērnu mijiedarbībā bērniem 22-30 mēnešu vecumā, un noskaidrots, vai pastāv statistiski nozīmīgas atšķirības agresivitātes rādījumos bērniem ar un bez autiskā spektra traucējumu iezīmēm. Pētāmo izlase: 115 bērni vecumā no 22 līdz 30 mēnešiem, apakšizlasē 18 bērni. Tika izmantota bērna uzvedības novērtējuma anketa (Achenbach & Rescorla, 2000), adaptēta un pielietota „AS Detect” aptauja (Barbaro, 2016), Ģentes audzināšanas aptauja - vecāku versija (Van Leeuwen et.al., 2004), vecāku - bērnu mijiedarbības video novērojumi (Eyberg, 2002). Pētījuma rezultāti norāda uz statistiski n…
For a real job? : Views on the teaching of competence in working life by students with Autism Spectrum Disorder (ASD)
2021
In this study, twelve young students on the autism spectrum were interviewed on preparation for working life, employment guidance, the challenges and strengths of the autism spectrum, and suitable teaching methods. Interviews were supported by a structured and illustrated questionnaire. The data were analysed using key statistics. The results showed that, from the students’ perspective, the most important issues in preparation for work are familiarisation with different jobs, guidance in searching for a suitable job, evaluation of the suitability of the working environment, integration of occupational safety into work skills, and acquiring conversational skills in the workplace. The selecti…
Search for low-energy neutrinos from astrophysical sources with Borexino
2019
We report on searches for neutrinos and antineutrinos from astrophysical sources performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso in Italy. Electron antineutrinos ($\bar{\nu}_e$) are detected in an organic liquid scintillator through the inverse $\beta$-decay reaction. In the present work we set model-independent upper limits in the energy range 1.8-16.8 MeV on neutrino fluxes from unknown sources that improve our previous results, on average, by a factor 2.5. Using the same data set, we first obtain experimental constraints on the diffuse supernova $\bar{\nu}_e$ fluxes in the previously unexplored region below 8 MeV. A search for $\bar{\nu}_e$ in the solar ne…
Characterization of Food Packaging Films with Blackcurrant Fruit Waste as a Source of Antioxidant and Color Sensing Intelligent Material
2021
Chitosan and pectin films were enriched with blackcurrant pomace powder (10 and 20% (w/w)), as bio-based material, to minimize food production losses and to increase the functional properties of produced films aimed at food coatings and wrappers. Water vapor permeability of active films increased up to 25%, moisture content for 27% in pectin-based ones, but water solubility was not significantly modified. Mechanical properties (tensile strength, elongation at break and Young’s modulus) were mainly decreased due to the residual insoluble particles present in blackcurrant waste. FTIR analysis showed no significant changes between the film samples. The degradation temperatures, determined by D…
Clinical and MRI measures to identify non-acute MOG-antibody disease in adults
2022
Abstract MRI and clinical features of myelin oligodendrocyte glycoprotein (MOG)-antibody disease may overlap with those of other inflammatory demyelinating conditions posing diagnostic challenges, especially in non-acute phases and when serologic testing for MOG antibodies is unavailable or shows uncertain results. We aimed to identify MRI and clinical markers that differentiate non-acute MOG-antibody disease from aquaporin 4 (AQP4)-antibody neuromyelitis optica spectrum disorder and relapsing remitting multiple sclerosis, guiding in the identification of patients with MOG-antibody disease in clinical practice. In this cross-sectional retrospective study, data from 16 MAGNIMS centres were i…