Nowadays, astronomers want to observe gaps in exozodiacal disks to confirmthe presence of exoplanets, or even make actual images of these companions.Four hundred and fifty years ago, Jean-Dominique Cassini did a similar study ona closer object: Saturn. After joining the newly created Observatoire de Parisin 1671, he discovered 4 of Saturn's satellites (Iapetus, Rhea, Tethys andDione), and also the gap in its rings. He made these discoveries observingthrough the best optics at the time, made in Italy by famous opticians likeGiuseppe Campani or Eustachio Divini. But was he really able to observe thisblack line in Saturn's rings? That is what a team of optical scientists fromObservatoire de Paris - LESIA with the help of Onera and Institut d'Optiquetried to find out, analyzing the lenses used by Cassini, and still preserved inthe collection of the observatory. The main difficulty was that even if thelenses have diameters between 84 and 239 mm, the focal lengths are between 6and 50 m, more than the focal lengths of the primary mirrors of future ELTs.The analysis shows that the lenses have an exceptionally good quality, with awavefront error of approximately 50 nm rms and 200 nm peak-to-valley, leadingto Strehl ratios higher than 0.8. Taking into account the chromaticity of theglass, the wavefront quality and atmospheric turbulence, reconstructions of hisobservations tend to show that he was actually able to see the division namedafter him.
Paraneoplastic pemphigus (PNP) is recognised in most cases after diagnosis of malignant and benign haematological tumours. PNP usually presents with severe and diffuse oral ulcerations, ocular lesions, lichen planus-like skin lesions and frequently genital ulcerations. We describe the uncommon case of a patient unaware of any neoplasia with a unique ulcerated oral lesion with histological (acantholysis of the basal epithelial layer, necrotic keratinocytes and pronounced regenerative hyperplasia) and immunofluorescent (direct immunofluorescence test exhibited immunoglobulin IgG, fibrinogen and C3 deposition in intercellular areas and along the basement membrane; indirect immunofluorescence test performed on rat bladder showed bright fluorescence) features suggestive of PNP. Diagnosis of PNP was strengthened by the subsequent discovery of monoclonal gammopathy. The reported case is quite unusual if we consider the clinical appearance of the oral lesions and the patient's negative medical history. Following serological examinations, the patient proved to have monoclonal gammopathy of undetermined significance (MGUS), one of the most common premalignant plasma cell disorders.
International audienceThis paper is concerned with the counting and random sampling of plane graphs (simple planar graphs embedded in the plane). Our main result is a bijection between the class of plane graphs with triangular outer face, and a class of oriented binary trees. The number of edges and vertices of the plane graph can be tracked through the bijection. Consequently, we obtain counting formulas and an efficient random sampling algorithm for rooted plane graphs (with arbitrary outer face) according to the number of edges and vertices. We also obtain a bijective link, via a bijection of Bona, between rooted plane graphs and 1342-avoiding permutations. 1 Introduction A planar graph is a graph that can be embedded in the plane (drawn in the plane without edge crossing). A pla-nar map is an embedding of a connected planar graph considered up to deformation. The enumeration of pla-nar maps has been the subject of intense study since the seminal work of Tutte in the 60's [20] showing that many families of planar maps have beautiful counting formulas. Starting with the work of Cori and Vauquelin [10] and then Schaeffer [18, 19], bijective constructions have been discovered that provide more transparent proofs of such formulas. The enumeration of planar graphs has also been the focus of a lot of efforts, culminating with the asymptotic counting formulas obtained by Giménez and Noy [16]. In this paper we focus on simple planar maps (planar maps without loops nor multiple edges), which are also called plane graphs. This family of planar maps has, quite surprisingly, not been considered until fairly recently. This is probably due to the fact that loops and multiple edges are typically allowed in studies about planar maps, whereas they are usually forbidden in studies about planar graphs. At any rate, the first result about plane graphs was an exact algebraic expressio
This paper addresses the problem of human action recognition. Typically, visual action recognition systems need visual training examples for all actions that one wants to recognize. However, the total number of possible actions is staggering as not only are there many types of actions but also many possible objects for each action type. Normally, visual training examples are needed for all actions of this combinatorial explosion of possibilities. To address this problem, this paper is a first attempt to propose a general framework for unseen action recognition in still images by exploiting both visual and language models. Based on objects recognized in images by means of visual features, the system suggests the most plausible actions exploiting off-the-shelf language models. All components in the framework are trained on universal datasets, hence the system is general, flexible, and able to recognize actions for which no visual training example has been provided. This paper shows that our model yields good performance on unseen action recognition. It even outperforms a state-of-the-art Bag-of-Words model in a realistic scenario where few visual training examples are available.
1.Introduction Direct formic acid fuel cells, DFAFCs, have been attracted much attention since they can generate higher power density than that of the other direct liquid fuel cells, such as direct methanol fuel cell and direct ethanol fuel cell. The intensive researches for the anode catalyst have been carried out, on the other hand, there has been little study for the cell structure and the cathode performance of the DFAFC. To generate higher power output, the optimization of the cell structure is quite important. Therefore, in this study, the effect of the membrane thickness on the power density and over potential behaviors of the anode and cathode was investigated to optimize the cell structure of the DFAFCs. 2. Experimental The membrane electrode assembly with a 4.84 cm active area was prepared. 8 mg/cm of Pd black was coated on the carbon cloth for the anode and 8 mg/cm Pt black was coated on the carbon paper for the cathode. 10 wt% of ionomer was contained in both electrodes. Nafion 117, 115 and NR 212 were used as an electrolyte membrane. The MEA was fabricated by sandwiching the membrane between the anode and cathode and hot pressing them at 408 K and 5 MPa for 3min. The DFAFCs were operated with active mode. Figure 1 shows the schematic diagrams of the active cell with reference electrode. Using reference electrodes, the electrode potentials of the anode and cathode were individually measured. Current-voltage, i-v, characteristics were measured using different MEA having different membranes with 7 M formic acid solution and 1 l/min of oxygen. The cell temperature was fixed at 30 C. The cell resistance was also measured using a digital fuel cell AC ohmic meter (FC-100R, CHINO) 3. Result and discussion Figure 2 shows the effect of the membrane thickness on the current-power, i.e., i-p, characteristics obtained from i-v measurement. The highest power density of 301 mW/cm was obtained when NR 212 was used. The ohmic resistances were 21 mΩ at NR 212, 46 mΩ at Nafion 115 and 57 mΩ at Nafion 117. Since the ohmic resistance of the NR 212 was lowest in the three membranes, the NR 212 showed highest performance. However, the performance difference between three membranes could not be explained by only the difference of the ohmic resistance. Figure 3 shows the electrode potentials during the i-v measurements when different membranes were used. A large difference in the anode potentials was observed between three membranes, and the over-potential of the anode increased with increasing the membrane thickness. From these results, NR 212 showed highest performance due to the lowest resistance and the anode over-potential in three membranes. Fig.1 Schematic diagrams of the active cell with reference electrode.
Observing the actions of others has been shown to affect motor learning, but does it have effects on sensory systems as well? It has been recently shown that motor learning that involves actual physical practice is also associated with plasticity in the somatosensory system. Here, we assessed the idea that observational learning likewise changes somatosensory function. We evaluated changes in somatosensory function after human subjects watched videos depicting motor learning. Subjects first observed video recordings of reaching movements either in a clockwise or counterclockwise force field. They were then trained in an actual force-field task that involved a counterclockwise load. Measures of somatosensory function were obtained before and after visual observation and also following force-field learning. Consistent with previous reports, video observation promoted motor learning. We also found that somatosensory function was altered following observational learning, both in direction and in magnitude, in a manner similar to that which occurs when motor learning is achieved through actual physical practice. Observation of the same sequence of movements in a randomized order did not result in somatosensory perceptual change. Observational learning and real physical practice appear to tap into the same capacity for sensory change in that subjects that showed a greater change following observational learning showed a reliably smaller change following physical motor learning. We conclude that effects of observing motor learning extend beyond the boundaries of traditional motor circuits, to include somatosensory representations.
A classical issue in many applied fields is to obtain an approximating surface to a given set of data points. This problem arises in Computer-Aided Design and Manufacturing (CAD/CAM), virtual reality, medical imaging, computer graphics, computer animation, and many others. Very often, the preferred approximating surface is polynomial, usually described in parametric form. This leads to the problem of determining suitable parametric values for the data points, the so-called surface parameterization. In real-world settings, data points are generally irregularly sampled and subjected to measurement noise, leading to a very difficult nonlinear continuous optimization problem, unsolvable with standard optimization techniques. This paper solves the parameterization problem for polynomial Bézier surfaces by applying the firefly algorithm, a powerful nature-inspired metaheuristic algorithm introduced recently to address difficult optimization problems. The method has been successfully applied to some illustrative examples of open and closed surfaces, including shapes with singularities. Our results show that the method performs very well, being able to yield the best approximating surface with a high degree of accuracy