Gender homophily from spatial behavior in a primary school: a sociometric study

We investigate gender homophily in the spatial proximity of children (6 to 12 years old) in a French primary school, using time-resolved data on face-to-face proximity recorded by means of wearable sensors. For strong ties, i.e., for pairs of children who interact more than a defined threshold, we find statistical evidence of gender preference that increases with grade. For weak ties, conversely, gender homophily is negatively correlated with grade for girls, and positively correlated with grade for boys. This different evolution with grade of weak and strong ties exposes a contrasted picture of gender homophily

Tomographic reconstruction of neopterous Carboniferous insect nymphs

Two new polyneopteran insect nymphs from the Montceau-les-Mines Lagerstätte of France are presented. Both are preserved in three dimensions, and are imaged with the aid of X-ray micro-tomography, allowing their morphology to be recovered in unprecedented detail. One–Anebos phrixos gen. et sp. nov.–is of uncertain affinities, and preserves portions of the antennae and eyes, coupled with a heavily spined habitus. The other is a roachoid with long antennae and chewing mouthparts very similar in form to the most generalized mandibulate mouthparts of extant orthopteroid insects. Computer reconstructions reveal limbs in both specimens, allowing identification of the segments and annulation in the tarsus, while poorly developed thoracic wing pads suggest both are young instars. This work describes the morphologically best-known Palaeozoic insect nymphs, allowing a better understanding of the juveniles’ palaeobiology and palaeoecology. We also consider the validity of evidence from Palaeozoic juvenile insects in wing origin theories. The study of juvenile Palaeozoic insects is currently a neglected field, yet these fossils provide direct evidence on the evolution of insect development. It is hoped this study will stimulate a renewed interest in such work

Influence of Workload on Auditory Evoked Potentials in a Single-stimulus Paradigm

Mental workload can be assessed via neurophysiological markers. Temporal features such as event related potentials (ERPs) are one of those which are very often described in the literature. However, most of the studies that evaluate their sensitivity to workload use secondary tasks. Yet potentials elicited by ignored stimuli could provide mental state monitoring systems with less intrusive probing methods. For instance, auditory probing systems could be used in adaptive driving or e-learning applications. This study evaluates how workload influences auditory evoked potentials (AEPs) elicited by a single-stimulus paradigm when probes are to be ignored. Ten participants performed a Sternberg memory task on a touchpad with three levels of difficulty plus a view-only condition. In addition, they performed two ecological tasks of their choice, one deemed easy (e.g. reading novels), and the other difficult (e.g. programming). AEPs were elicited thanks to pure tones presented during the memory task retention period, and during the whole extent of the external tasks. Performance and AEPs were recorded and analyzed. Participants’ accuracy decreased linearly with increasing workload, whereas the difference in amplitude between the P3 and its adjacent components, N2 and SW, increased. This reveals the relevance of this triphasic sequence for mental workload assessment

Relationship between casting modulus and grain size in cast A356 aluminium alloys

Microstructure of Al-Si alloy castings depends most generally on melt preparation and on the cooling rate imposed by the thermal modulus of the component. In the case of Al-Si alloys, emphasis is put during melt preparation on refinement of pro-eutectic (Al) grains and on modification of the Al-Si eutectic. Thermal analysis has been used since long to check melt preparation before casting, i.e. by analysis of the cooling curve during solidification of a sample cast in an instrumented cup. The conclusions drawn from such analysis are however valid for the particular cooling conditions of the cups. It thus appeared of interest to investigate how these conclusions could extrapolate to predict microstructure in complicated cast parts showing local changes in the solidification conditions. For that purpose, thermal analysis cups and instrumented sand and die castings with different thermal moduli and thus cooling rates have been made, and the whole set of cooling curves thus recorded has been analysed. A statistical analysis of the characteristic features of the cooling curves related to grain refinement in sand and die castings allowed determining the most significant parameters and expressing the cube of grain size as a polynomial of these parameters. After introduction of a further parameter quantifying melt refining an excellent correlation, with a R2 factor of 0.99 was obtained

SlideImages: A Dataset for Educational Image Classification

In the past few years, convolutional neural networks (CNNs) have achieved impressive results in computer vision tasks, which however mainly focus on photos with natural scene content. Besides, non-sensor derived images such as illustrations, data visualizations, figures, etc. are typically used to convey complex information or to explore large datasets. However, this kind of images has received little attention in computer vision. CNNs and similar techniques use large volumes of training data. Currently, many document analysis systems are trained in part on scene images due to the lack of large datasets of educational image data. In this paper, we address this issue and present SlideImages, a dataset for the task of classifying educational illustrations. SlideImages contains training data collected from various sources, e.g., Wikimedia Commons and the AI2D dataset, and test data collected from educational slides. We have reserved all the actual educational images as a test dataset in order to ensure that the approaches using this dataset generalize well to new educational images, and potentially other domains. Furthermore, we present a baseline system using a standard deep neural architecture and discuss dealing with the challenge of limited training data.Comment: 8 pages, 2 figures, to be presented at ECIR 202

A motion capture study to measure the feeling of synchrony in romantic couples and in professional musicians

The feeling of synchrony is fundamental for most social activities and prosocial behaviors. However, little is known about the behavioral correlates of this feeling and its modulation by intergroup differences. We previously showed that the subjective feeling of synchrony in subjects involved in a mirror imitation task was modulated by objective behavioral measures, as well as contextual factors such as task difficulty and duration of the task performance. In the present study, we extended our methodology to investigate possible interindividual differences. We hypothesized that being in a romantic relationship or being a professional musician can modulate both implicit and explicit synchronization and the feeling of synchrony as well as the ability to detect synchrony from a third person perspective. Contrary to our hypothesis, we did not find significant differences between people in a romantic relationship and control subjects. However, we observed differences between musicians and control subjects. For the implicit synchrony (spontaneous synchronization during walking), the results revealed that musicians that had never met before spontaneously synchronized their movements earlier among themselves than control subjects, but not better than people sharing a romantic relationship. Moreover, in explicit behavioral synchronization tasks (mirror game), musicians reported earlier feeling of synchrony and had less speed errors than control subjects. This was in interaction with tasks difficulty as these differences appeared only in tasks with intermediate difficulty. Finally, when subjects had to judge synchrony from a third person perspective, musicians had a better performance to identify if they were present or not in the videos. Taken together, our results suggest that being a professional musician can play a role in the feeling of synchrony and its underlying mechanisms

The “Mirage” Sensor in a Industrial Environment: Optical and Thermal Losses Determinations

Since the first “Mirage” experiment run in the laboratory of ESPCI in 1979 [1], this method has been used by many other laboratories for the determination of optical and thermal properties and for non destructive evaluation [2] [3] [4]

Terrestrial groundwater and nutrient discharge along the 240-km-long Aquitanian coast

We collected samples from sea water, runnel water, beach pore waters, water from the unconfined surficial aquifer discharging at the beach face, groundwater, and rainwater from the Aquitanian coast in order to determine the flux of dissolved inorganic nitrogen (DIN), phosphorus and silica from terrestrial submarine groundwater discharge (SGD). The flux of fresh groundwater was obtained from a water balance calculation based on precipitation and evapotranspiration and assessment of the coastal watershed from hydrograph separation. Waters with intermediate salinities between sea water and freshwaters are found all along the 240-km-long coast, indicating that SGD is ubiquitous. The estimated fresh water flux is 2.25 m3 d− 1 m− 1 longshore. Terrestrial SGD provides a DIN flux of 9·106 mol each year to the adjacent coastal zone. This flux is about four times lower than the release of DIN due to tidally driven saline SGD. The freshwater DIN flux is low because the upland land use consists almost exclusively of pine forest. Dissolved organic nitrogen represents more than 60% of the total dissolved nitrogen flux. Dissolved iron, phosphorus and silica have much higher concentrations in the anoxic forest aquifer than in the fresh-water end-member of the subterranean estuary sampled in the upper beach aquifer. This suggests that the salinity gradient of the estuary does not correspond to a redox gradient. The redox front between anoxic groundwater and fresh oxic waters occurs below the soil-depleted foredune/yellow dune. Anoxic P- and Si-rich waters seep directly on the beach face only in the north Gironde, where the foredunes are eroded. This study reveals the role of the sandy foredune aquifer in biogeochemical fluxes from SGD, which is to dilute and oxidize waters from the unconfined surficial upland aquifer

The Subjective Sensation of Synchrony: an Experimental Study

People performing actions together have a natural tendency to synchronize their behavior. Consistently, people doing a task together build internal representations not only of their actions and goals, but also of the other people performing the task. However, little is known about which are the behavioral mechanisms and the psychological factors affecting the subjective sensation of synchrony, or "connecting" with someone else. In this work, we sought to find which factors induce the subjective sensation of synchrony, combining motion capture data and psychological measures. Our results show that the subjective sensation of synchrony is affected by performance quality together with task category, and time. Psychological factors such as empathy and negative subjective affects also correlate with the subjective sensation of synchrony. However, when people estimate synchrony as seen from a third person perspective, their psychological factors do not affect the accuracy of the estimation. We suggest that to feel this sensation it is necessary to, first, have a good joint performance and, second, to assume the existence of an attention monitoring mechanism that reports that the attention of both participants (self and other) is focused on the task

Weak Lensing Mass Reconstruction using Wavelets

This paper presents a new method for the reconstruction of weak lensing mass maps. It uses the multiscale entropy concept, which is based on wavelets, and the False Discovery Rate which allows us to derive robust detection levels in wavelet space. We show that this new restoration approach outperforms several standard techniques currently used for weak shear mass reconstruction. This method can also be used to separate E and B modes in the shear field, and thus test for the presence of residual systematic effects. We concentrate on large blind cosmic shear surveys, and illustrate our results using simulated shear maps derived from N-Body Lambda-CDM simulations with added noise corresponding to both ground-based and space-based observations.Comment: Accepted manuscript with all figures can be downloaded at: http://jstarck.free.fr/aa_wlens05.pdf and software can be downloaded at http://jstarck.free.fr/mrlens.htm