Evaluation of atlas-based segmentation of hippocampi in healthy humans

Introduction and aim: Region of interest (ROI)-based functional magnetic resonance imaging (fMRI) data analysis relies on extracting signals from a specific area which is presumed to be involved in the brain activity being studied. The hippocampus is of interest in many functional connectivity studies for example in epilepsy as it plays an important role in epileptogenesis. In this context, ROI may be defined using different techniques. Our study aims at evaluating the spatial correspondence of hippocampal ROIs obtained using three brain atlases with hippocampal ROI obtained using an automatic segmentation algorithm dedicated to the hippocampus. Material and methods: High-resolution volumetric T1-weighted MR images of 18 healthy volunteers (five females) were acquired on a 3T scanner. Individual ROIs for both hippocampi of each subject were segmented from the MR images using an automatic hippocampus and amygdala segmentation software called SACHA providing the gold standard ROI for comparison with the atlas-derived results. For each subject, hippocampal ROIs were also obtained using three brain atlases: PickAtlas available as a commonly used software toolbox; automated anatomical labeling (AAL) atlas included as a subset of ROI into PickAtlas toolbox and a frequency-based brain atlas by Hammers et al. The levels of agreement between the SACHA results and those obtained using the atlases were assessed based on quantitative indices measuring volume differences and spatial overlap. The comparison was performed in standard Montreal Neurological Institute space, the registration being obtained with SPM5 (http://www.fil.ion.ucl.ac.uk/spm/). Results: The mean volumetric error across all subjects was 73% for hippocampal ROIs derived from AAL atlas; 20% in case of ROIs derived from the Hammers atlas and 107% for ROIs derived from PickAtlas. The mean false-positive and false-negative classification rates were 60% and 10% respectively for the AAL atlas; 16% and 32% for the Hammers atlas and 6% and 72% for the PickAtlas. Conclusion: Though atlas-based ROI definition may be convenient, the resulting ROIs may be poor representations of the hippocampus in some studies critical to under- or oversampling. Performance of the AAL atlas was inferior to that of the Hammers atlas. Hippocampal ROIs derived from PickAtlas are highly significantly smaller, and this results in the worst performance out of three atlases. It is advisable that the defined ROIs should be verified with knowledge of neuroanatomy before using it for further data analysis

Competitive segmentation of the hippocampus and the amygdala from MRI scans

The hippocampus and the amygdala are two brain structures which play a central role in several fundamental cognitive processes. Their segmentation from Magnetic Resonance Imaging (MRI) scans is a unique way to measure their atrophy in some neurological diseases, but it is made difficult by their complex geometry. Their simultaneous segmentation is considered here through a competitive homotopic region growing method. It is driven by relational anatomical knowledge, which enables to consider the segmentation of atrophic structures in a straightforward way. For both structures, this fast algorithm gives results which are comparable to manual segmentation with a better reproducibility. Its performances regarding segmentation quality, automation and computation time, are amongst the best published data.L’hippocampe et l’amygdale sont deux structures cérébrales intervenant dans plusieurs fonctions cognitives fondamentales. Leur segmentation, à partir de volumes d’imagerie par résonance magnétique (IRM), est un outil essentiel pour mesurer leur atteinte dans certaines pathologies neurologiques, mais elle est rendue difficile par leur géométrie complexe. Nous considérons leur segmentation simultanée par une méthode de déformation homotopique compétitive de régions. Celle-ci est guidée par des connaissances anatomiques relationnelles ; ceci permet de considérer directement des structures atrophiées. Rapide, l’algorithme donne, pour les deux structures, des résultats comparables à la segmentation manuelle avec une meilleure reproductibilité. Ses performances, concernant la qualité de la segmentation, le degré d’automatisation et le temps de calcul, sont parmi les meilleures de la littérature

Роль автотранспорта в обеспечении международной торговли стран ЕАЭС

Regionalization and digitalization are significant factors in the development of international transport, including road transport. Liberalization of mutual trade, creation of a single customs territory and gradual elimination of non-tariff barriers within integration unions have generally led to an increase in the speed of international movement of goods. Today the EAEU is the most advanced integration project in the post-Soviet space. Transport as an area of Eurasian integration occupies a special place in the integration process due to the spatial characteristics of the association and its transit potential. It is expected that the common transport space (CTS) will be created without exceptions and limitations by 2025. Trade relations of EAEU member states are provided by all modes of transport (including pipeline transport, but this study focuses only on long-distance modes of transport). In terms of countries, road transport plays the largest role in transport support of foreign trade in the Kyrgyz Republic, and the smallest role in the Russian Federation, where other modes of transport are more involved, mainly sea and rail transport. At the same time, the Russian and Kazakh segments account for more than 95 % of the freight transportations of the EAEU countries carried out by road transport, which determined the relevance of the research topic. This investigation presents the role of road transport in ensuring the international transport of goods of the EAEU countries. The results of the study, aimed at determining the role of road transport in the provision of international freight transportation of EAEU countries, were obtained through an empirical analysis of the road transport industry. The analysis identified the key features of the development of this segment in the EAEU countries. In turn, the assessment of the place of road transport in ensuring foreign trade of EAEU countries was carried out on the basis of two quantitative indicators of transport as an industry - the volume of freight traffic and cargo turnover.Регионализация и цифровизация являются значимыми факторами развития международного транспорта, в том числе автомобильного. Либерализация взаимной торговли, создание единой таможенной территории и постепенное устранение нетарифных барьеров внутри интеграционных объединений в целом привели к повышению скорости международного товародвижения. На сегодняшний день ЕАЭС - наиболее продвинутый интеграционный проект на постсоветском пространстве. Транспорт как направление евразийской интеграции занимает особое место в интеграционном процессе ввиду пространственных характеристик объединения и его транзитного потенциала. Ожидается, что единое транспортное пространство (ЕТП) без изъятий и ограничений будет создано к 2025 г. Торговые связи стран - участниц ЕАЭС обеспечиваются всеми видами транспорта (в частности трубопроводным, однако данное исследование фокусируется только на магистральных видах транспорта). В страновом разрезе наибольшую роль в транспортном обеспечении внешней торговли автомобильный транспорт играет в Кыргызской Республике, наименьшую - в Российской Федерации, где более задействованы другие виды транспорта - главным образом морской и железнодорожный. При этом на российский и казахстанский сегменты приходится более 95 % грузоперевозок стран ЕАЭС, осуществляемых автомобильным транспортом, что и определило актуальность темы исследования. Представлена роль автотранспорта в обеспечении международных перевозок грузов стран ЕАЭС. Результаты исследования, направленного на определение роли автотранспорта в обеспечении международных перевозок грузов стран ЕАЭС, были получены путем эмпирического анализа отрасли автотранспортных перевозок. Анализ определил ключевые особенности развития данного сегмента в странах ЕАЭС. В свою очередь, оценка места автомобильного вида транспорта в обеспечении внешней торговли стран ЕАЭС проведена на основе двух количественных показателей работы транспорта как отрасли - объема грузоперевозок и грузооборота

Atomic fountains and optical clocks at SYRTE: status and perspectives

In this article, we report on the work done with the LNE-SYRTE atomic clock ensemble during the last 10 years. We cover progress made in atomic fountains and in their application to timekeeping. We also cover the development of optical lattice clocks based on strontium and on mercury. We report on tests of fundamental physical laws made with these highly accurate atomic clocks. We also report on work relevant to a future possible redefinition of the SI second

Drug related problems and pharmacist interventions in a geriatric unit employing electronic prescribing

Background Computerised physician order entry (CPOE) and the integration of a pharmacist in clinical wards have been shown to prevent drug related problems (DRPs). Objectives The primary objective was to make an inventory of the DRPs and resident pharmacist on-ward interventions (PIs) identified in a geriatric acute care unit using CPOE system. The secondary objective was to evaluate the physicians\u27 acceptance of the proposed interventions. Setting A 26-bed geriatric ward of a 1,300-bed teaching hospital. Method A 6-month descriptive study with prescription analysis and recommendations to physicians by a resident pharmacist during five half days a week. Main outcome measures Patients\u27 characteristics, number of prescribed drugs per patient, nature and frequency of DRPs and PIs, physicians\u27 acceptance and drugs questioned. Results Resident pharmacist reviewed 311 patients and identified 241 DRPs. One hundred and fifty-two patients (49 %) had at least one DRP (mean +/- A SD age 87 +/- A 6 years, mean +/- A SD number of prescribed drugs 10.7 +/- A 3.4). Most frequent DRPs were: untreated indication (n = 58, 24.1 %), dose too high (n = 46, 19.1 %), improper administration (n = 31, 12.9 %) and drug interactions (n = 23, 9.5 %). The rate of physicians\u27 acceptance was 90.0 % (7.5 % refusals, 2.5 % not assessable). DRPs related to CPOE system misuse (n = 35, 14.5 %) appeared as a worrying phenomenon (e.g., errors in selecting dosage or unit, or duplication of therapy). Conclusion A resident pharmacist detected various DRPs. Most PIs were accepted. DRPs related to the misuse of the CPOE system appeared potentially dangerous and need particular attention by healthcare professionals. The description of the DRPs is an essential step for implementation of targeted clinical pharmacy services in order to optimize pharmacists\u27 job time

The FENE dumbbell polymer model: existence and uniqueness of solutions for the momentum balance equation

We consider the FENE dumbbell polymer model which is the coupling of the incompressible Navier-Stokes equations with the corresponding Fokker-Planck-Smoluchowski di ffusion equation. We show global well-posedness in the case of a 2D bounded domain. We assume in the general case that the initial velocity is sufficiently small and the initial probability density is sufficiently close to the equilibrium solution; moreover an additional condition on the coeffcients is imposed. In the corotational case, we only assume that the initial probability density is sufficiently close to the equilibrium solution

Segmentation compétitive de l'hippocampe et de l'amygdale à partir de volumes IRM

L'hippocampe et l'amygdale sont deux structures cérébrales intervenant dans plusieurs fonctions cognitives fondamentales. Leur segmentation est un outil essentiel pour mesurer leur atteinte dans certaines pathologies neurologiques, mais elle est rendue difficile par leur complexité. Nous considérons leur segmentation simultanée par une méthode de déformation homotopique compétitive de régions. celle-ci est guidée par des connaissances anatomiques relationnelles, et non des a priori statistiques, pour pouvoir considérer des structures atrophiées. Rapide, l'algorithme donne des résultats satisfaisants pour les deux structures par rapport à la segmentation manuelle et à la littérature

Nouméa: a new multi-mission calibration and validation site for past and future altimetry missions?

Today, monitoring the evolution of sea level in coastal areas is of importance, since almost 11 % of the world's population lives in low-lying areas. Reducing uncertainties in sea level estimates requires a better understanding of both altimetry measurements and local sea level dynamics. In New Caledonia, the Nouméa lagoon is an example of this challenge, as altimetry, coastal tide gauge, and vertical land motions from global navigation satellite systems (GNSSs) do not provide consistent information. The GEOCEAN-NC 2019 field campaign addresses this issue with deployments of in situ instruments in the lagoon (GNSS buoy, pressure gauge, etc.), with a particular focus on the crossover of one Jason-series track and two Sentinel-3A missions tracks. In this study, we propose a method to virtually transfer the Nouméa tide gauge at the altimetry crossover point, using in situ data from the field campaign. Following the philosophy of calibration and validation (Cal/Val) studies, we derive absolute altimeter bias time series over the entire Jason and Sentinel-3A periods. Overall, our estimated altimeter mean biases are slightly larger by 1–2 cm compared to Corsica and Bass Strait results, with inter-mission biases in line with those of Bass Strait site. Uncertainties still remain regarding the determination of our vertical datum, only constrained by the three days of the GNSS buoy deployment. With our method, we are able to re-analyse about 20 years of altimetry observations and derive a linear trend of −0.2 ± 0.1 mm yr−1 over the bias time series. Compared to previous studies, we do not find any significant uplift in the area, which is more consistent with the observations of inland permanent GNSS stations. These results support the idea of developing Cal/Val activities in the lagoon, which is already the subject of several experiments for the scientific calibration phase of the SWOT wide-swath altimetry mission.</p

Performance of the Scintillator System Prototype of the NUCLEON Space Experiment

Abstract The NUCLEON space experiment has been proposed to perform direct measurements of CR energy spectrum and composition up to E ∼ 10 15 eV. The NUCLEON detector consists of layers of different detectors: scintillator detectors with WLS fibers and silicon pad and microstrip ones. The results of beam and space qualification tests of the scintillator detectors are presented