Adaptability and possibilistic combination: application to multi-cameras vision

This paper presents the problem of uncertain information combination through the framework of possibility theory. Three aggregation behaviours exist according to available information are in conflict or not : conjunction, trade-off and disjunction. Although this classification is attractive, it is not satisfying because it is too coarse ; indeed, the sudden change from a combination mode to another one creates some discontinuities for the computation of resulting distributions . This is not desirable ; to overcome this problem, Dubois and Prade have exhibited four adaptive combination rules . Their combination mode adapts itself to the amount of conflict existing between different data. The most elaborate of these four rules allows to combine from conjunction to disjunction . We present a behavioural study of this rule and we apply it to a problem of computer vision . Finally, we establish some properties concerning its sensitivity to corrupt values ; in particular we highlight an hysteresis phenomenon, that is a memory ofpast conflicts .Cet article présente le problème de la combinaison d'informations incertaines à travers le cadre de la théorie des possibilités. Trois comportements de combinaison existent suivant que les informations disponibles sont en conflit ou non: la conjonction, le compromis et la disjonction. Bien que cette classification soit séduisante, elle n'est pas satisfaisante car trop grossière; en effet, le passage soudain d'un mode de combinaison à un autre engendre des discontinuités dans le calcul des distributions résultantes. Cela n'est pas souhaitable; pour surmonter ce problème, Dubois et Prade ont proposé quatre règles de combinaison adaptative. Leur mode d'agrégation s'adapte automatiquement à la quantité de conflit présente entre les différentes données. La plus élaborée de ces quatre règles permet de combiner de la conjonction et la disjonction. Nous présentons une étude comportementale de cette règle et nous l'appliquons à un problème de vision artificielle. Enfin, nous établissons quelques proprietés concernant sa sensibilité face à des mesures aberrantes; en particulier, nous mettons en évidence un phénomène d'hystérésis, c'est-à-dire une mémoire des conflits passé

Recognition of 2D modelized objects by a discrete relaxation method

In this paper, a discrete relaxation method is described . The aim of this method is the recognition of 2D objects, a model of which having prealably be established. The model is based on two kinds of features : straight segments and circles . The approach is both forward and backward ; so, it is not necessary to detect all the primitives at the beginning of the procedure new primitives may be detected, if necessary, during the relaxation procedure .L'article présente une méthode de relaxation discrète pour la reconnaissance d'objets plans dont on a effectué une modélisation préalable . Cette modélisation est réalisée à l'aide de primitives du type segments de droite ou cercles . L'approche est descendante et ascendante, permettant, par un retour au niveau de l'image pour détecter de nouvelles primitives, d'éviter un prétraitement exhaustif de l'image

Responses of substantia gelatinosa neurons to putative neurotransmitters in an in vitro preparation of the adult rat spinal cord

Extracellular recordings were performed from neurons of the substantia gelatinosa (SG) in an in vitro preparation obtained from the spinal cord of adult rats. About 40% of neurons were spontaneously active. They could be synaptically influenced by low and high threshold fiber input entering the spinal cord through dorsal and ventral and ventral roots. Repetitive low threshold stimulation led to a transient increase in activity of a number of these neurons, whereas high intensity stimulation predominantly reduced excitability. The majority of non-spontaneously active neurons responded to an increase of stimulus intensity covariantly with an increase in firing rate. The excitatory effect of phoretically administeredl-glutamate as well as synaptically induced and spontaneous activity was reduced or abolished by phoretically administered GABA, glycine or the enkephalin-analogued-Ala2-d-Leu5-enkephalin. The actions of the enkephalin analogue were blocked by phoretically applied naloxone. The findings are consistent with the notion from in vivo investigations of a structurally and functionally heterogeneous population of neurons which display a responsiveness to microtopically applied putative neurotransmitters resembling dorsal horn neurons in deeper layers

Cloud thermodynamic phase inferred from merged POLDER and MODIS data

International audienceThe global spatial and diurnal distribution of cloud properties is a key issue for understanding the hydrological cycle, and critical for advancing efforts to improve numerical weather models and general circulation models. Satellite data provides the best way of gaining insight into global cloud properties. In particular, the determination of cloud thermodynamic phase is a critical first step in the process of inferring cloud optical and microphysical properties from satellite measurements. It is important that cloud phase be derived together with an estimate of the confidence of this determination, so that this information can be included with subsequent retrievals (optical thickness, effective particle radius, and ice/liquid water content). In this study, we combine three different and well documented approaches for inferring cloud phase into a single algorithm. The algorithm is applied to data obtained by the MODIS (MODerate resolution Imaging Spectroradiometer) and POLDER3 (Polarization and Directionality of the Earth Reflectance) instruments. It is shown that this synergistic algorithm can be used routinely to derive cloud phase along with an index that helps to discriminate ambiguous phase from confident phase cases. The resulting product provides a semi-continuous confidence index ranging from confident liquid to confident ice instead of the usual discrete classification of liquid phase, ice phase, mixed phase (potential combination of ice and liquid particles), or simply unknown phase clouds. This approach is expected to be useful for cloud assimilation and modeling efforts while providing more insight into the global cloud properties derived from satellite data

Cloud information content analysis of multi-angular measurements in the oxygen A-band: application to 3MI and MSPI

The vertical distribution of cloud cover has a significant impact on a large number of meteorological and climatic processes. Cloud top altitude and cloud geometrical thickness are then essential. Previous studies established the possibility of retrieving those parameters from multi-angular oxygen A-band measurements. Here we perform a study and comparison of the performances of future instruments. The 3MI (Multi-angle, Multi-channel and Multi-polarization Imager) instrument developed by EUMETSAT, which is an extension of the POLDER/PARASOL instrument, and MSPI (Multi-angles Spectro-Polarimetric Imager) develoloped by NASA's Jet Propulsion Laboratory will measure total and polarized light reflected by the Earth's atmosphere–surface system in several spectral bands (from UV to SWIR) and several viewing geometries. Those instruments should provide opportunities to observe the links between the cloud structures and the anisotropy of the reflected solar radiation into space. Specific algorithms will need be developed in order to take advantage of the new capabilities of this instrument. However, prior to this effort, we need to understand, through a theoretical Shannon information content analysis, the limits and advantages of these new instruments for retrieving liquid and ice cloud properties, and especially, in this study, the amount of information coming from the A-Band channel on the cloud top altitude (CTOP) and geometrical thickness (CGT). We compare the information content of 3MI A-Band in two configurations and that of MSPI. Quantitative information content estimates show that the retrieval of CTOP with a high accuracy is possible in almost all cases investigated. The retrieval of CGT seems less easy but possible for optically thick clouds above a black surface, at least when CGT > 1–2 km

Anaesthetic management of people with multiple sclerosis.

There is a lack of published guidelines on the management of patients with multiple sclerosis (MS) undergoing procedures that require anaesthesia and respective advice is largely based on retrospective studies or case reports. The aim of this paper is to provide recommendations for anaesthetists and neurologists for the management of patients with MS requiring anaesthesia. This review covers issues related to the anaesthetic management of patients with MS, with a focus on preoperative assessment, choice of anaesthetic techniques and agents, side-effects of drugs used during anaesthesia and their potential impact on the disease evolution, drug interactions that may occur, and the need to use monitoring devices. A systematic PubMed research was performed to retrieve relevant articles

Intestinal adhesion due to previous uterine surgery as a risk factor for delayed diagnosis of uterine rupture: a case report

<p>Abstract</p> <p>Introduction</p> <p>Uterine rupture is a life-threatening condition both to mothers and fetuses. Its early diagnosis and treatment may save their lives. Previous myomectomy is a high risk factor for uterine rupture. Intestinal adhesion due to previous myomectomy may also prevent early diagnosis of uterine rupture.</p> <p>Case presentation</p> <p>A 38-year-old primiparous non-laboring Japanese woman with a history of myomectomy was admitted in her 34^thweek due to lower abdominal pain. Although the pain was slight and her vital signs were stable, computed tomography revealed massive fluid collection in her abdominal cavity, which led us to perform a laparotomy. Uterine rupture had occurred at the site of the previous myomectomy; however, the small intestine was adhered tightly to the rupture, thus masking it. The baby was delivered through a low uterine segment transverse incision. The ruptured uterine wall was reconstructed.</p> <p>Conclusion</p> <p>Intestinal adhesion due to a prior myomectomy occluded a uterine rupture, possibly masking its symptoms and signs, which may have prevented early diagnosis.</p

Human influence on growing-period frosts like the early April 2021 in Central France

International audienceAbstract. In early April 2021 several days of harsh frost affected central Europe. This led to very severe damage in grapevine and fruit trees in France, in regions where young leaves had already unfolded due to unusually warm temperatures in the preceding month (March 2021). We analysed with observations and 172 climate model simulations how human-induced climate change affected this event over central France, where many vineyards are located. We found that, without human-caused climate change, such temperatures in April or later in spring would have been even lower by 1.2 ∘C (0.75 to 1.7 ∘C). However, climate change also caused an earlier occurrence of bud burst that we characterized in this study by a growing degree day index value. This shift leaves young leaves exposed to more winter-like conditions with lower minimum temperatures and longer nights, an effect that overcompensates the warming effect. Extreme cold temperatures occurring after the start of the growing season such as those of April 2021 are now 2 ∘C colder (0.5 to 3.3 ∘C) than in preindustrial conditions, according to observations. This observed intensification of growing-period frosts is attributable, at least in part, to human-caused climate change with each of the five climate model ensembles used here simulating a cooling of growing-period annual temperature minima of 0.41 ∘C (0.22 to 0.60 ∘C) since preindustrial conditions. The 2021 growing-period frost event has become 50 % more likely (10 %–110 %). Models accurately simulate the observed warming in extreme lowest spring temperatures but underestimate the observed trends in growing-period frost intensities, a fact that yet remains to be explained. Model ensembles all simulate a further intensification of yearly minimum temperatures occurring in the growing period for future decades and a significant probability increase for such events of about 30 % (20 %–40 %) in a climate with global warming of 2 ∘C

Synergistic use of Lagrangian dispersion and radiative transfer modelling with satellite and surface remote sensing measurements for the investigation of volcanic plumes: the Mount Etna eruption of 25–27 October 2013

Abstract. In this paper we combine SO2 and ash plume dispersion modelling with satellite and surface remote sensing observations to study the regional influence of a relatively weak volcanic eruption from Mount Etna on the optical and micro-physical properties of Mediterranean aerosols. We analyse the Mount Etna eruption episode of 25–27 October 2013. The evolution of the plume along the trajectory is investigated by means of the FLEXible PARTicle Lagrangian dispersion (FLEXPART) model. The satellite data set includes true colour images, retrieved values of volcanic SO2 and ash, estimates of SO2 and ash emission rates derived from MODIS (MODerate resolution Imaging Spectroradiometer) observations and estimates of cloud top pressure from SEVIRI (Spinning Enhanced Visible and InfraRed Imager). Surface remote sensing measurements of aerosol and SO2 made at the ENEA Station for Climate Observations (35.52° N, 12.63° E; 50 m a.s.l.) on the island of Lampedusa are used in the analysis. The combination of these different data sets suggests that SO2 and ash, despite the initial injection at about 7.0 km altitude, reached altitudes around 10–12 km and influenced the column average aerosol particle size distribution at a distance of more than 350 km downwind. This study indicates that even a relatively weak volcanic eruption may produce an observable effect on the aerosol properties at the regional scale. The impact of secondary sulfate particles on the aerosol size distribution at Lampedusa is discussed and estimates of the clear-sky direct aerosol radiative forcing are derived. Daily shortwave radiative forcing efficiencies, i.e. radiative forcing per unit AOD (aerosol optical depth), are calculated with the LibRadtran model. They are estimated between −39 and −48 W m−2 AOD−1 at the top of the atmosphere and between −66 and −49 W m−2 AOD−1 at the surface, with the variability in the estimates mainly depending on the aerosol single scattering albedo. These results suggest that sulfate particles played a large role in the transported plume composition and radiative forcing, while the contribution by ash particles was small in the volcanic plume arriving at Lampedusa during this event