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See detailDetecting awareness in patients with disorders of consciousness using a hybrid brain–computer interface
Pan, Jiahui; Xie, Qiuyou; He, Yanbin et al

in Journal of Neural Engineering (2014)

Objective. The bedside detection of potential awareness in patients with disorders of consciousness (DOC) currently relies only on behavioral observations and tests; however, the misdiagnosis rates in ... [more ▼]

Objective. The bedside detection of potential awareness in patients with disorders of consciousness (DOC) currently relies only on behavioral observations and tests; however, the misdiagnosis rates in this patient group are historically relatively high. In this study, we proposed a visual hybrid brain–computer interface (BCI) combining P300 and steady-state evoked potential (SSVEP) responses to detect awareness in severely brain injured patients. Approach. Four healthy subjects, seven DOC patients who were in a vegetative state (VS, n = 4) or minimally conscious state (MCS, n = 3), and one locked-in syndrome (LIS) patient attempted a command-following experiment. In each experimental trial, two photos were presented to each patient; one was the patientʼs own photo, and the other photo was unfamiliar. The patients were instructed to focus on their own or the unfamiliar photos. The BCI system determined which photo the patient focused on with both P300 and SSVEP detections. Main results. Four healthy subjects, one of the 4 VS, one of the 3 MCS, and the LIS patient were able to selectively attend to their own or the unfamiliar photos (classification accuracy, 66–100%). Two additional patients (one VS and one MCS) failed to attend the unfamiliar photo (50–52%) but achieved significant accuracies for their own photo (64–68%). All other patients failed to show any significant response to commands (46–55%). Significance. Through the hybrid BCI system, command following was detected in four healthy subjects, two of 7 DOC patients, and one LIS patient. We suggest that the hybrid BCI system could be used as a supportive bedside tool to detect awareness in patients with DOC. [less ▲]

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See detailDetecting Awareness in the Vegetative State
Owen, Adrian; Coleman, Martin; Boly, Mélanie ULg et al

in Science (2006)

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See detailDetecting consciousness in a total Locked-in syndrome: an active event related paradigm
Schnakers, Caroline ULg; Perrin, Fabien; Schabus, Manuel et al

in Neurocase : Case Studies in Neuropsychology, Neuropsychiatry & Behavioural Neurology (2009), 25

Total locked-in syndrome is characterized by tetraplegia, anarthria and paralysis of eye motility. In this study, consciousness was detected in a 21-year-old woman who presented a total locked-in syndrome ... [more ▼]

Total locked-in syndrome is characterized by tetraplegia, anarthria and paralysis of eye motility. In this study, consciousness was detected in a 21-year-old woman who presented a total locked-in syndrome after a basilar artery thrombosis (49 days post-injury) using an active event-related paradigm. The patient was presented sequences of names containing the patient's own name and other names. The patient was instructed to count her own name or to count another target name. Similar to 4 age- and gender-matched healthy controls, the P3 response recorded for the voluntarily counted own name was larger than while passively listening. This P3 response was observed 14 days before the first behavioral signs of consciousness. This study shows that our active event-related paradigm allowed to identify voluntary brain activity in a patient who would behaviorally be diagnosed as comatose. [less ▲]

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See detailDetecting consciousness in minimally conscious patients
Vanhaudenhuyse, Audrey ULg; Schnakers, Caroline ULg; Boly, Mélanie ULg et al

in Réanimation (2007), 16

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See detailDetecting consciousness in severe brain injury
Noirhomme, Quentin ULg

Conference (2011, January 13)

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See detailDetecting Consciousness with a Brain-computer Interface
Noirhomme, Quentin ULg; Lesenfants, Damien ULg; Lehembre, Remy ULg et al

in Pons, J. L.; Torricelli, D.; Pajaro, M. (Eds.) Converging Clinical and Engineering Research on Neurorehabilitation (2012, November)

Recent electrophysiological and neuroimaging studies showed command-specific changes in EEG or fMRI signals of unresponsive patients providing motor-independent evidence of conscious thoughts. These ... [more ▼]

Recent electrophysiological and neuroimaging studies showed command-specific changes in EEG or fMRI signals of unresponsive patients providing motor-independent evidence of conscious thoughts. These promising results have paved the way for a new application for Brain-computer Interface (BCI): detecting consciousness in patients with disorders of consciousness (DOC). In the present abstract, we review the first results obtained by BCI-like applications in patients with DOC and discuss the challenges facing BCI research. We believe that patients with DOC may benefit from BCI based diagnosis. BCIs may detect changes in the signal in response to command and, in some cases, may permit communication. [less ▲]

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See detailDetecting consciousness with voluntary control of sniffing
Charland-Verville, Vanessa ULg; Lesenfants, Damien; Sela, Lee et al

Conference (2012)

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See detailDetecting correlated di-hadron pairs: about the extraction of transversity and beyond
Radici, Marco; Bacchetta, Alessandro; Courtoy, Aurore ULg

in World Scientific (2013)

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See detailDetecting faint companions with PIONIER
Absil, Olivier ULg

Conference (2011, October 25)

One of the main goals of the PIONIER visitor instrument at VLTI is to search for faint companions around relatively bright stars. In this talk, we present a general method to search for companions in ... [more ▼]

One of the main goals of the PIONIER visitor instrument at VLTI is to search for faint companions around relatively bright stars. In this talk, we present a general method to search for companions in PIONIER data, with a particular emphasis on the exploitation of closure phases. Our search method is illustrated on a few exemples, including the detection of companions at the ~1% contrast level, and non-detections showing upper limits of a few 0.1% on the contrast of any companion within the interferometric field-of-view. In particular, we demonstrate that the small near-infrared excesses previously reported around several main-sequence stars with precision near-infrared interferometry is not related to the presence of low-mass companions around the target stars. The current limitations of PIONIER are shortly discussed, and we derive some general guidelines on how to best use an interferometric array for faint companion detection. Finally, we discuss how the dynamic range and angular resolution provided by of PIONIER can serve various scientific goals, ranging from low-mass companions around main sequence stars to massive binaries. We show that PIONIER could detect objects at the brown dwarf / planet boundary for young low-mass stars residing in nearby associations. [less ▲]

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See detailDetecting large-scale diversity patterns in tropical trees: can we trust commercial forest inventories?
Réjou-Méchain, Maxime; Fayolle, Adeline ULg; Nasi, Robert et al

in Forest Ecology & Management (2011), 261(2), 187-194

In this paper we seek to identify the floristic determination biases contained in large-scale commercial inventories conducted by logging companies and to determine whether this impacts on the observed ... [more ▼]

In this paper we seek to identify the floristic determination biases contained in large-scale commercial inventories conducted by logging companies and to determine whether this impacts on the observed patterns of alpha and beta diversity. The study focused on floristic data recently collected by industrial timber companies in the tropical forests of the Central African Republic (28,229 0.5-ha plots spread over 14,000km2). A subset of these plots (n = 1107) was later re-sampled for controlling purposes by experienced botanists. The proportion of agreement between the two samplings was assessed for each species and independently for small and large trees, and at genus and family resolutions. Unsurprisingly, large trees and common species were more accurately identified than small trees and rare species. We found that the quality of the floristic determination increased slightly from species to families. We also detected a significant variation between concessions in the quality of the floristic determination that was more dependent on working conditions during forest inventories than on field workers. Contrary to a widespread belief, we did not find a strong bias toward commercial species, showing that commercial inventory data could also be valid for non-commercial species in ecological studies. Finally, we found that both alpha and beta diversity patterns in commercial inventories were highly consistent with those of the re-sampled inventory. This latter result shows that commercial inventories are well suited to detect large-scale patterns of floristic variation. Large-scale commercial inventories could thus play an important role in the identification of large-scale patterns in tropical tree diversity. This could enhance our ability to manage tropical forests by designing representative reserve networks and developing management plans that integrate diversity patterns at the landscape scale. [less ▲]

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See detailDetecting microbial patterns in relation to soil agricultural practices and the plant development stage
Degrune, Florine ULg; Dufrêne, Marc ULg; Taminiau, Bernard ULg et al

Poster (2014, December 02)

Agricultural practices have a strong impact on soil bacteria and fungi. Furthermore, microbial community composition can change with the stage of plant development. We are interested in exploring these ... [more ▼]

Agricultural practices have a strong impact on soil bacteria and fungi. Furthermore, microbial community composition can change with the stage of plant development. We are interested in exploring these effects in relation to changes induced by agriculture and plant stage in soil conditions. Some bacteria are influenced only by the plant stage, which induces changes in soil humidity, pH, nitrates, and carbon. We would thus expect these bacteria to be highly sensitive to these parameters. Other bacteria are affected only by the tillage practice applied. Further study is needed to identify the soil parameters responsible for this effect. The plant stage also has a great impact on fungal community composition. [less ▲]

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See detailDetecting natural canopy gaps in Amazonian rainforest.
Colson, F; Gond, V; Freycon, V et al

in Bois et Forêts des Tropiques (2006), 289(3), 69-79

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See detailDetecting patient subgroups using reduced set of disease-related markers with iterative pruning Principal Component Analysis (ipPCA)
Chaichoompu, Kridsadakorn ULg; Cleynen, Isabelle; Fouladi, Ramouna ULg et al

Poster (2015, October 03)

Genetic markers such as Single Nucleotide Polymorphisms (SNPs) can be used to find subgroups of populations or patients with carefully selected clustering algorithms. The iterative pruning principal ... [more ▼]

Genetic markers such as Single Nucleotide Polymorphisms (SNPs) can be used to find subgroups of populations or patients with carefully selected clustering algorithms. The iterative pruning principal component analysis (ipPCA) has been shown to be a powerful tool to identify fine substructures within general populations based on SNP profiles. Usually, SNPs contributing to such profiles have passed rigorous quality control procedures, similar to the ones used for GWAs. Alternatively, attention is restricted to a smaller subset such as PCA-correlated SNPs. Here, we applied ipPCA on real-life data consisting of the 163 known inflammatory-bowel disease (IBD) associated loci in 13,400 healthy individuals and 29,500 IBD (16,902 Crohn’s disease (CD), and 12,598 ulcerative colitis (UC)) patients from the IIBDGC. Prior to clustering by ipPCA, in each group separately, we regressed out the first five Principal Components (PCs) that were computed from a filtered panel of genome-wide SNPs, to account for general population strata. Next, we applied ipPCA on the healthy group, to learn about the presence of a population-specific partitioning in controls. Then we performed three subphenotype analyses: CD only, UC only and the combined group of CD and UC patients (IBD). For each patient subgroup analysis and for the ipPCA analysis on controls, we highlighted and compared the key SNP drivers. CD patients could be molecularly reclassified in two groups, and similar for UC patients. The combined patient group could be subdivided in four groups. Finally, we compared demographic and clinical features among the different groups and looked for meaningful characterizations of adjusted patient clusters by performing pathway analysis on driver genes. [less ▲]

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See detailDetecting population substructures
Chaichoompu, Kridsadakorn ULg

Scientific conference (2014, June 05)

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See detailDetecting preferential flow and transport in soils using electrical resistivity tomography
Vanderborght, Jan; Oberdoerster, Christoph; Garré, Sarah ULg et al

Conference (2009)

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See detailDetecting regional anthropogenic trends in ocean acidification against natural variability
Friedrich, T.; Timmermann, A.; Abe-Ouchi, A. et al

in Nature Climate Change (2012), 2

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See detailDetecting transition radiation from a magnetic moment
Ivanov, Igor ULg; Karlovets, Dmitry

in Physical Review Letters (2013), 110(26), 2648015

Electromagnetic radiation can be emitted not only by particle charges but also by magnetic moments and higher electric and magnetic multipoles. However, experimental proofs of this fundamental fact are ... [more ▼]

Electromagnetic radiation can be emitted not only by particle charges but also by magnetic moments and higher electric and magnetic multipoles. However, experimental proofs of this fundamental fact are extremely scarce. In particular, the magnetic moment contribution has never been observed in any form of polarization radiation. Here, we propose to detect it using vortex electrons carrying large orbital angular momentum ℓ. The relative contribution of the orbital angular momentum-induced magnetic moment, ℓℏω/Ee, becomes much larger than the spin-induced contribution ℏω/Ee, and it can be observed experimentally. As a particular example, we consider transition radiation from vortex electrons obliquely incident on an interface between a vacuum and a dispersive medium, in which the magnetic moment contribution manifests itself via a left-right angular asymmetry. For electrons with Ee=300  keV and ℓ=100–1000, we predict an asymmetry of the order of 0.1%–1%, which could be measured with existing technology. Thus, vortex electrons emerge as a new tool in the physics of electromagnetic radiation. [less ▲]

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See detailDetecting Triangle Inequality Violations in Internet Coordinate Systems
Kaafar, Mohamed Ali; Cantin, François ULg; Gueye, Cheikh Ahmadou Bamba ULg et al

in Future Networks 2009 (2009, June 18)

Internet Coordinate Systems (ICS) have been proposed as a method for estimating delays between hosts without direct measurement. However, they can only be accurate when the triangle inequality holds for ... [more ▼]

Internet Coordinate Systems (ICS) have been proposed as a method for estimating delays between hosts without direct measurement. However, they can only be accurate when the triangle inequality holds for Internet delays. Actually Triangle Inequality Violations (TIVs) are frequent and are likely to remain a property of the Internet due to routing policies or path inflation. In this paper we propose methods to detect TIVs with high confidence by observing various metrics such as the relative estimation error on the coordinates. Indeed, the detection of TIVs can be used for mitigating their impact on the ICS itself, by excluding some disturbing nodes from clusters running their own ICS, or more generally by improving their neighbor selection mechanism. [less ▲]

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See detailDetecting Triangle Inequality Violations in Internet Coordinate Systems by Supervised Learning
Liao, Yongjun ULg; Kaafar, Mohamed Ali; Gueye, Bamba et al

in Lecture Notes in Computer Science (2009, May 12), 5550

Internet Coordinates Systems (ICS) are used to predict Internet distances with limited measurements. However the precision of an ICS is degraded by the presence of Triangle Inequality Violations (TIVs ... [more ▼]

Internet Coordinates Systems (ICS) are used to predict Internet distances with limited measurements. However the precision of an ICS is degraded by the presence of Triangle Inequality Violations (TIVs). Simple methods have been proposed to detect TIVs, based e.g. on the empirical observation that a TIV is more likely when the distance is underestimated by the coordinates. In this paper, we apply supervised machine learning techniques to try and derive more powerful criteria to detect TIVs. We first show that (ensembles of) Decision Trees (DTs) learnt on our datasets are very good models for this problem. Moreover, our approach brings out a discriminative variable (called OREE), which combines the classical estimation error with the variance of the estimated distance. This variable alone is as good as an ensemble of DTs, and provides a much simpler criterion. If every node of the ICS sorts its neighbours according to OREE, we show that cutting these lists after a given number of neighbours, or when OREE crosses a given threshold value, achieves very good performance to detect TIVs. [less ▲]

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See detailDetecting urban road network accessibility problems using taxi GPS data
Cui, JianXun; Liu, Feng; Janssens, Davy et al

in Journal of Transport Geography (2016), 51

Urban population growth and economic development have led to the creation of new communities, jobs and services at places where the existing road network might not cover or efficiently handle traffic ... [more ▼]

Urban population growth and economic development have led to the creation of new communities, jobs and services at places where the existing road network might not cover or efficiently handle traffic. This generates isolated pockets of areas which are difficult to reach through the transport system. To address this accessibility problem, we have developed a novel approach to systematically examine the current urban land use and road network conditions as well as to identify poorly connected regions, using GPS data collected from taxis. This method is composed of four major steps. First, city-wide passenger travel demand patterns and travel times are modeled based on GPS trajectories. Upon this model, high density residential regions are then identified, and measures to assess accessibility of each of these places are developed. Next, the regions with the lowest level of accessibility among all the residential areas are detected, and finally the detected regions are further examined and specific transport situations are analyzed. By applying the proposed method to the Chinese city of Harbin, we have identified 20 regions that have the lowest level of accessibility by car among all the identified residential areas. A serious reachability problem to petrol stations has also been discovered, in which drivers from 92.6% of the residential areas have to travel longer than 30 min to refill their cars. Furthermore, the comparison against a baseline model reveals the capacity of the derived measures in accounting for the actual travel routes under divergent traffic conditions. The experimental results demonstrate the potential and effectiveness of the proposed method in detecting car-based accessibility problems, contributing towards the development of urban road networks into a system that has better reachability and more reduced inequity. [less ▲]

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