Highway traffic monitoring on medium resolution satellite images

International audienceThese last years, earth observation imagery has significantly improved. Public satellites such as WorldView-3 can now produce images with a Ground Sample Distance of 31cm, reaching an equivalent resolution than aerial images. Perhaps more importantly, the revisit frequency has also been greatly enhanced: providers such as Planet can now acquire images of an area on a daily basis. These major improvements are fueled by an increasing demand for frequent objects detection. An application generating a particular interest is vehicle detection. Indeed, vehicle detection can give to public and private actors valuable data such as traffic monitoring and parking occupancy rate estimations. Several datasets, such as DOTA or VehSat, already exist, allowing researchers to train machine learning algorithms to detect vehicles. However, these datasets focus on relatively high definition and expensive aerial and satellite images. In this paper, we will present a method for detecting vehicles on medium resolution satellite images, with a GSD comprised between 1 and 5 meters. This approach can notably be used on Planet images, allowing to monitor traffic of an area on a daily basis

Foreword

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Revising consensus in portal hypertension

Portal hypertension is associated with the most severe complications of cirrhosis, including ascites, hepatic encephalopathy, and bleeding from gastro-esophageal varices. Despite the progress achieved over the last decades, the 6-week mortality associated with variceal bleeding is still in the order of 10–20%. Awareness of the difficulty inherent to the evaluation of diagnostic tools and the design and conduct of good clinical trials for the treatment of portalhypertensionhas led to theorganization, since1986,of a series of consensus meetings. The first one was organized by Andrew Burroughs in Groningen, The Netherlands [1]. After Groningen, other meetings followed, in Baveno in 1990 (Baveno I) [2] and in 1995 (Baveno II) [3,4], in Milan in 1992 [5], in Reston, USA, in 1996 [6], in Stresa in 2000 (Baveno III) [7,8], again in Baveno in 2005 (Baveno IV) [9,10], and in Atlanta in 2007 [11]. The aims of these meetings were to develop definitions of key events in portal hypertension and variceal bleeding, to review the existing evidence on the natural history, the diagnosis and the therapeutic modalities of portal hypertension, and to issue evidence-based recommendations for the conduct of clinical trials and the management of patients. All these meetings were successful and produced consensus statements on some important points, although some issues remained unsettled. To continue the work of the previous meetings, a Baveno V workshop was held on May 21–22, 2010. The workshop was attended by many of the experts responsible for most of the major achievements of the last years in this field. Many of them had attended the previous meetings as well. The main fields of discussion of the Baveno V workshop were the same as in Baveno I–IV, i.e. the definitions of key events concerning the bleeding episode and the therapeutic options in patients with portal hypertension. For each of these topics, a series of consensus statements were discussed and agreed upon. As in Baveno IV, whenever applicable, the level of existing evidence was evaluated and the recommendations were ranked according to the Oxford System [12] (i.e.: level of evidence from 1 = highes

Thrombin regulates the ability of Schwann cells to support neuritogenesis and to maintain the integrity of the nodes of Ranvier

Schwann cells (SC) are characterized by a remarkable plasticity that enables them to promptly respond to nerve injury promoting axonal regeneration. In peripheral nerves after damage SC convert to a repair-promoting phenotype activating a sequence of supportive functions that drive myelin clearance, prevent neuronal death, and help axon growth and guidance. Regeneration of peripheral nerves after damage correlates inversely with thrombin levels. Thrombin is not only the key regulator of the coagulation cascade but also a protease with hormone-like activities that affects various cells of the central and peripheral nervous system mainly through the protease-activated receptor 1 (PAR1). Aim of the present study was to investigate if and how thrombin could affect the axon supportive functions of SC. In particular, our results show that the activation of PAR1 in rat SC cultures with low levels of thrombin or PAR1 agonist peptides induces the release of molecules, which favor neuronal survival and neurite elongation. Conversely, the stimulation of SC with high levels of thrombin or PAR1 agonist peptides drives an opposite effect inducing SC to release factors that inhibit the extension of neurites. Moreover, high levels of thrombin administered to sciatic nerve ex vivo explants induce a dramatic change in SC morphology causing disappearance of the Cajal bands, enlargement of the Schmidt-Lanterman incisures and calcium-mediated demyelination of the paranodes. Our results indicate thrombin as a novel modulator of SC plasticity potentially able to favor or inhibit SC pro-regenerative properties according to its level at the site of lesion

The thrombin/PAR1 axis as regulator of Schwann cell functions in health and disease

Thrombin, the key eff ector protease of the coagulation cascade, mediates hemostasis, throm bosis, and infl ammatory responses to vascular injury predominantly acting through its main receptor, protease-activated receptor 1 (PAR1). PAR1 is a member of a family of four G-protein coupled receptors which are activated by proteolytic cleavage of their N-terminal extracellular domains. The expression and role of PAR1 in peripheral nervous system is still poorly inves tigated, although high PAR1 expression was found in the dorsal root ganglia and in the non compacted Schwann cell myelin microvilli at the nodes of Ranvier. Our previous results indicate that rat Schwann cell plasticity can be widely modulated by thrombin acting through PAR1 (Pompili et al., Mol and Cell Neurosci 2017; Pompili et al., Eur J Histochem 2020). Here we extend those previous data showing that thrombin regulates prolifer ation and survival of human Schwann cells increasing the expression of factors, such as matrix metalloprotease 2 (MMP2) and macrophage migration inhibitory factor (MIF), which are key in modulating nerve regeneratio

Rôle actuel de la capsule endoscopique dans la détection des tumeurs néoplasiques de l’intestin grêle

Although small-bowel tumors are a small proportion of gastrointestinal neoplasms recent studies suggest that the incidence of these diseases is increasing. In fact, using new diagnostic modalities, their frequency has been shown to be slightly superior than previously thought. Until recently, diagnosis and management of these tumors were delayed by the difficult of access to the small bowel and the poor diagnostic capabilities of the available diagnostic techniques. An array of new methods has recently been developed, increasing the possibility of detecting these tumors at an earlier stage. In this particular subset of patients capsule endoscopy, despite its possible limitations, may provide crucial information changing the subsequent patient management and possibly influencing the long-term clinical outcome.Bien que les tumeurs de l’intestin grêle ne représentent qu’une faible proportion des lésions néoplasiques du tractus digestif, de récentes études ont mis en évidence une légère augmentation de leur incidence. En fait, grâce aux nouvelles modalités diagnostiques, leur fréquence s’est avérée légèrement supérieure à ce qui était précédemment rapporté. Jusqu’à très récemment, le diagnostic et la prise en charge de ces tumeurs étaient retardés en raison d’un accès difficile à l’intestin grêle et aux faibles capacités diagnostiques des moyens techniques disponibles. Tout un éventail de nouvelles méthodes ont récemment été mises au point, améliorant la possibilité de détecter ces lésions à un stade plus précoce. Pour cette catégorie spécifique de patients avec lésions de l’intestin grêle, la capsule endoscopique, en dépit de ses limites, peut fournir une information cruciale influant par conséquent sur la prise en charge du patient et sur les résultats cliniques au long cours

Hyperhomocysteinemia in premature arterial disease: examination of cystathionine β-synthase alleles at the molecular level

Hyperhomocysteinemia occurs in approximately 30% of the patients with premature occlusive arterial disease (POAD). Some of these exhibit significantly reduced fibroblast cystathionine β-synthase (CBS) activities, suggesting that they may be heterozygous for CBS deficiency. To test this possibility, we studied cDNA derived from four well characterized patients with POAD, exhibiting hyperhomocysteinemia and reduced CBS activities, from four normal controls, and from four obligatory heterozygotes for CBS deficiency. Lysates of individual colonies of E.coli, containing full-length PCR-amplification products in the expression vector, pKK388.1, were tested for CBS activity. cDNA from at least seven of the eight possible independent POAD alleles encoded catalytically active, stable CBS which exhibited normal response to both PLP and AdoMet. The sequences of all 3'-untranslated regions of all seven isolated POAD alleles were identical to the normal, wild-type CBS sequences. The results of the expression studies were confirmed for one POAD patient by determining the full-length cDNA sequences for both alleles; these were entirely normal over the complete length of the cDNA. In contrast, the screening method correctly distinguished mutant from normal alleles in all four obligatory heterozygotes studied. We conclude that CBS mRNAs from POAD individuals are free from inactivating mutations, including all 33 previously identified in heterozygous carriers and homocystinuric patient