Search results for " artifacts"
showing 10 items of 31 documents
Flexible multi-beam light-sheet fluorescence microscope for live imaging without striping artifacts
2018
The development of light-sheet fluorescence microscopy (LSFM) has greatly expanded the experimental capabilities in many biological and biomedical research fields, enabling for example live studies of murine and zebrafish neural activity or of cell growth and division. The key feature of the method is the selective illumination of a sample single plane, providing an intrinsic optical sectioning and allowing direct 2D image recording. On the other hand, this excitation scheme is more affected by absorption or scattering artifacts in comparison to point scanning methods, leading to un-even illumination. We present here an easily implementable method, based on acousto-optical deflectors (AOD),…
Unsupervised Eye Blink Artifact Identification in Electroencephalogram
2018
International audience; The most prominent type of artifact contaminating electroencephalogram (EEG) signals is the eye blink (EB) artifact. Hence, EB artifact detection is one of the most crucial pre-processing step in EEG signal processing before this artifact can be removed. In this work, an approach that identifies EB artifacts without human supervision and automated varying threshold setting is proposed and evaluated. The algorithm functions on the basis of correlation between two EEG electrodes, Fp1 and Fp2, followed by EB artifact threshold determination utilizing the amplitude displacement from the mean. The proposed approach is validated and evaluated in terms of accuracy and error…
The Application of the Essential Oils of Thymus vulgaris L. and Crithmum maritimum L. as Biocidal on Two Tholu Bommalu Indian Leather Puppets
2021
The chemical profile of the Thymus vulgaris (Lamiaceae) essential oil (EO) was investigated in order to evaluate its biological properties against microorganisms affecting two Tholu Bommalu, typical Indian leather puppets stored at the International Puppets Museum “Antonio Pasqualino” of Palermo, Italy. A GC–MS analysis, using both polar and apolar columns, was used to determine the chemical composition of the essential oil. The aim of this study was to evaluate the antimicrobial effectiveness of the Thymus vulgaris and Crithmum maritimum essential oils in vapor phase to disinfect heritage leather puppets. Pieces of leather artifacts that were affected by different bacterial colonies were e…
Stones, Bones, and Hillfort: Radiocarbon Dating of Ķivutkalns Bronze-Working Center
2013
The Bronze Age site of ķivutkalns with its massive amount of archaeological artifacts and human remains is considered the largest bronze-working center in Latvia. The site is a unique combination of cemetery and hillfort believed to be built on top of each other. This work presents new radiocarbon dates on human and animal bone collagen that somewhat challenge this interpretation. Based on analyses using a Bayesian modeling framework, the present data suggest overlapping calendar year distributions for the contexts within the 1st millennium BC. The carbon and nitrogen isotopic ratios indicate mainly terrestrial dietary habits of studied individuals and nuclear family remains buried in one o…
Poggetti Vecchi (Tuscany, Italy): A late Middle Pleistocene case of human-elephant interaction
2019
Abstract A paleosurface with a concentration of wooden-, bone-, and stone-tools interspersed among an accumulation of fossil bones, largely belonging to the straight-tusked elephant Palaeoloxodon antiquus, was found at the bottom of a pool, fed by hot springs, that was excavated at Poggetti Vecchi, near Grosseto (Tuscany, Italy). The site is radiometrically dated to the late Middle Pleistocene, around 171,000 years BP. Notable is the association of the artifacts with the elephant bones, and in particular the presence of digging sticks made from boxwood (Buxus sp.). Although stone tools show evidence of use mainly on animal tissues, indicating some form of interaction between hominins and an…
Tractional Motion Machines: Tangent-Managing Planar Mechanisms as Analog Computers and Educational Artifacts
2012
Concrete and virtual machines play a central role in the both Unconventional Computing (machines as computers) and in Math Education (influence of artifacts on reaching/producing abstract thought). Here we will examine some fallouts in these fields for the Tractional Motion Machines, planar mechanisms based on some devices used to plot the solutions of differential equations by the management of the tangent since the late 17th century.
EMG artifacts removal during electrical stimulation, a CWT based technique
2014
International audience; A technique of artifacts removal based on the continuous wavelet transform is presented. It uses common mother wavelets to find the temporal localization of stimulation artifacts on electromyogram (EMG) signal during an electrically evoked contraction of a muscle. This method can be used with standard stimulation pulse waveforms like monophasics or biphasics ones. It uses a histogram representation to find the best threshold to apply on the CWT domain. The algotithm is presented with Haar wavelet and then it is used with common wavelet famillies such as Daubechies or Symlets.
Online Detection and Removal of Eye Blink Artifacts from Electroencephalogram
2020
The most prominent type of artifact contaminating electroencephalogram (EEG)signals are the eyeblink (EB) artifacts, which could potentially lead tomisinterpretation of the EEG signal. Online detection and removal of eyeblink artifacts from EEG signals are essential in applications such a Brain-Computer Interfaces (BCI), neurofeedback and epilepsy diagnosis. In this thesis, algorithms that combine unsupervised eyeblink artifact detection (eADA) with enhanced Empirical Mode Decomposition (FastEMD) and Canonical Correlation Analysis (CCA) are proposed,i.e. FastEMD-CCA2 and FastCCA, to automatically identify eyeblink artifacts andremove them in an online setting. FastEMD-CCA2 and FastCCA have …
Effect of Motion Artifact on Digital Camera Based Heart Rate Measurement
2017
International audience; Depression is one of the most prevalent mental disorders, burdening many people world-wide. A system with the potential of serving as a decision support system is proposed, based on novel features extracted from facial expression geometry and speech, by interpreting non-verbal manifestations of depression. The proposed system has been tested both in gender independent and gender based modes, and with different fusion methods. The algorithms were evaluated for several combinations of parameters and classification schemes, on the dataset provided by the Audio/Visual Emotion Challenge of 2013 and 2014. The proposed framework achieved a precision of 94.8% for detecting p…
L'albero di Persefone. Una nota introduttiva
2022
Il saggio discute il documentario di O. Cavalcanti, Persefone rivisitata, accurata e partecipata indagine sull’originale rito della Domenica delle Palme di Bova. In questa occasione sono recati processionalmente dei peculiari artefatti cerimoniali le pupazze, complessi intrecci di listelli di canna e di rami e foglie d’ulivo, rivestiti di fiori e di frutti. Intesi a rappresentare delle figure femminili, le pupazze sono destinate, al termine del rito processionale, ad essere smembrate e distribuite tra i fedeli affinché essi possano portare con sé, nelle proprie dimore, nei luoghi di lavoro una parte della potenza sacrale in esse racchiusa. In tutta evidenza le peculiari forme del rito e dei…