Age Verification as a Shield for Minors on the Internet: A Quixotic Search?

This article examines the issues raised by the use of the Internet by minors and children. In addition to being an outstanding source of information and a tool for connecting people in numerous affinity networks, the Internet has a dark side. Its resources may be abused for many bad deeds, including cyber bullying or facilitating encounters with child predators. One way to protect minors is to ensure that their age and identity is verified. However, this is not technically feasible without infringing on the privacy of these children as well as that of the adults who might have to be screened as well, if only to prove that there are not minors. After looking at the current problems, the existing laws, and comparing with developments in other countries, the article identifies some of legal and technical hurdles before stressing the important role of parents, guardians and education. While legislators are playing whack-a-mole, chasing child pornography, child predators, and cyber bullying, parents cannot let their children venture on the Internet unprepared and unsupervised. Despite its friendly face and its very approachable demeanor, the Internet is not a nanny. Rather, it is a reflection of the world, a combination of the good, the bad and the ugly

Spatial mode estimation for functional random fields with application to bioturbation problem

This work provides a useful tool to study the effects of bioturbation on the distribution of oxygen within sediments. We propose here heterogeneity measurements based on functional spatial mode. To obtain the mode, one usually needs to estimate the spatial probability density. The approach considered here consists in looking each observation as a curve that represents the history of the oxygen concentration at a fixed pixel

Quantification à partir d'images microtomographiques 3D de la structure des mousses solides

L'objectif de ce travail est de proposer une méthode de quantification des structures poreuses de mousses solides à partir d'images tomographiques à très haute résolution. Nous avons imagé des mousses polymères directement en 3D grâce à une technique de microtomographie par rayonnement synchrotron avec une résolution spatiale de 6.65 microns. Après la phase d'acquisition, des paramètres quantitatifs tels que l'épaisseur des parois de la matrices et le diamètre des bulles d'air doivent être mesurés. Nous comparons pour cela trois approches différentes : par ouverture, par épaisseur locale et par la méthode des sécantes (MIL). Ceci permet de valider les résultats des différentes méthodes. Cette quantification a été appliquée à la mesure sur image 3D des variations dues au changement de température dans le procédé de fabrication des mousses polymères

Palaeogenomic insights into the origins of French grapevine diversity

Ramos-Madrigal, Jazmín, Runge, Anne Kathrine Wiborg, Bouby, Laurent, Lacombe, Thierry, Castruita, José Alfredo Samaniego, Adam-Blondon, Anne-Françoise, Figueiral, Isabel, Hallavant, Charlotte, Martínez-Zapater, José M., Schaal, Caroline, Töpfer, Reinhard, Petersen, Bent, Sicheritz-Pontén, Thomas, This, Patrice, Bacilieri, Roberto, Gilbert, M. Thomas P., Wales, Nathan (2019): Palaeogenomic insights into the origins of French grapevine diversity. Nature Plants 5: 595-603, DOI: 10.1038/s41477-019-0437-

Polychromatic guide star: feasibility study

International audienceAdaptive optics at astronomical telescopes aims at correcting in real time the phase corrugations of incoming wavefronts caused by the turbulent atmosphere, as early proposed by Babcock. Measuring the phase errors requires a bright source located within the isoplanatic patch of the program source. The probability that such a reference source exists is a function of the wavelength, of the required image quality (Strehl ratio), of the turbulence optical properties, and of the direction of the observation. It turns out that the sky coverage is disastrously low in particular in the visible wavelength range where, unfortunately, the gain in spatial resolution brought by adaptive optics is the largest. Foy and Labeyrie have proposed to overcome this difficulty by creating an artificial point source in the sky in the direction of the observation relying on the backscattered light due to a laser beam. This laser guide star (hereinafter referred to as LGS) can be bright enough to allow us to accurately measure the wavefront phase errors, except for two modes which are the piston (not relevant in this case) and the tilt. Pilkington has emphasized that the round trip time of the laser beam to the mesosphere, where the LGS is most often formed, is significantly shorter than the typical tilt coherence time; then the inverse-return-of-light principle causes deflections of the outgoing and the ingoing beams to cancel. The apparent direction of the LGS is independent of the tilt. Therefore the tilt cannot be measured only from the LGS. Until now, the way to overcome this difficulty has been to use a natural guide star to sense the tilt. Although the tilt is sensed through the entire telescope pupil, one cannot use a faint source because $APEX 90% of the variance of the phase error is in the tilt. Therefore, correcting the tilt requires a higher accuracy of the measurements than for higher orders of the wavefront. Hence current adaptive optics devices coupled with a LGS face low sky coverage. Several methods have been proposed to get a partial sky coverage for the tilt. The only one providing us with a full sky coverage is the polychromatic LGS (hereafter referred to as PLGS). We present here a progress report of the R&D; program Etoile Laser Polychromatique et Optique Adaptative (ELP-OA) carried out in France to develop the PLGS concept. After a short recall of the principles of the PLGS, we will review the goal of ELP-OA and the steps to get over to bring it into play. We finally shortly described the effort in Europe to develop the LGS

Cholecystokinin B Receptor from Human Jurkat Lymphoblastic T Cells Is Involved in Activator Protein-1-Responsive Gene Activation

SUMMARY The aim of this study was to analyze the role of cholecystokinin (CCK B ) receptor in human lymphoblastic Jurkat T cells. We investigated the trophic effect resulting from activation of such a receptor by using the reporter gene strategy. For this purpose, we transiently transfected Jurkat T cells with the reporter plasmid p[(TRE)3-tk-Luc] and found that CCK-8 was able to dose-dependently induce luciferase expression related to activator protein-1 (AP-1) activation with a maximal response identical to that obtained with compounds known to activate AP-1 complex (quantitatively, the same level of induction was obtained with 1 nM 12-O-tetradecanoylphorbol-13-acetate, 100 M diacylglycerol, or 4 nM epidermal growth factor). The involvement of the CCK B receptor in such a stimulation was demonstrated by the inhibiting effect of the selective CCK B receptor antagonist 158. This effect was confirmed in COS-7 cells transfected with the cDNA of CCK B receptor cloned from Jurkat T cells. To better understand the AP-1-dependent luciferase expression in Jurkat T cells, we tested two specific inhibitors of serine/threonine phosphatases-1 and -2A: okadaic acid and calyculin A. These compounds strongly increased the phorbol-12-myristate-13-acetate response, whereas we have not observed a contribution of phosphatase inhibitors on a CCK-8-induced luciferase activity. To confirm that CCK B receptors are involved in AP-1 response, we investigated the CCK-8 effect on interleukin-2 expression, a natural endogenous gene regulated by several factors, including AP-1. In Jurkat T cells activated by phorbol-12-myristate-13-acetate and phytohemagglutinin, CCK-8 induced IL-2 expression. This induction was abolished by PD-135,158. Our results indicate that CCK-8 exerts a trophic effect in Jurkat T cells through stimulation of CCK B receptors by modulation of expression of AP-1-regulated genes. Several studies have shown that various gastrointestinal peptides may be involved in the control of proliferation of various tissues and neoplastic cells (1). For example, CCK was shown to increase growth of tumors in nude mice bearing transplanted pancreatic cancer tissues (2). CCK is also known to increase the number of animals developing nitrosamine-induced pancreatic cancers (3), and CCK was shown to increase the rate of growth of cultured pancreatic cancer cells (2). Similar observations were described for bombesin/ gastrin-releasing peptide in human glioblastoma in vitro and in vivo in small-cell lung carcinoma, prostatic, mammary, and pancreatic cancer cell lines (1). In addition, gastrointestinal peptides can function as autocrine growth factors in neoplastic tissues as shown for bombesin/gastrin-releasing peptide in small-cell lung carcinoma cells, for gastrin an

Polychromatic guide star: feasibility study

International audienceAdaptive optics at astronomical telescopes aims at correcting in real time the phase corrugations of incoming wavefronts caused by the turbulent atmosphere, as early proposed by Babcock. Measuring the phase errors requires a bright source located within the isoplanatic patch of the program source. The probability that such a reference source exists is a function of the wavelength, of the required image quality (Strehl ratio), of the turbulence optical properties, and of the direction of the observation. It turns out that the sky coverage is disastrously low in particular in the visible wavelength range where, unfortunately, the gain in spatial resolution brought by adaptive optics is the largest. Foy and Labeyrie have proposed to overcome this difficulty by creating an artificial point source in the sky in the direction of the observation relying on the backscattered light due to a laser beam. This laser guide star (hereinafter referred to as LGS) can be bright enough to allow us to accurately measure the wavefront phase errors, except for two modes which are the piston (not relevant in this case) and the tilt. Pilkington has emphasized that the round trip time of the laser beam to the mesosphere, where the LGS is most often formed, is significantly shorter than the typical tilt coherence time; then the inverse-return-of-light principle causes deflections of the outgoing and the ingoing beams to cancel. The apparent direction of the LGS is independent of the tilt. Therefore the tilt cannot be measured only from the LGS. Until now, the way to overcome this difficulty has been to use a natural guide star to sense the tilt. Although the tilt is sensed through the entire telescope pupil, one cannot use a faint source because $APEX 90% of the variance of the phase error is in the tilt. Therefore, correcting the tilt requires a higher accuracy of the measurements than for higher orders of the wavefront. Hence current adaptive optics devices coupled with a LGS face low sky coverage. Several methods have been proposed to get a partial sky coverage for the tilt. The only one providing us with a full sky coverage is the polychromatic LGS (hereafter referred to as PLGS). We present here a progress report of the R&D; program Etoile Laser Polychromatique et Optique Adaptative (ELP-OA) carried out in France to develop the PLGS concept. After a short recall of the principles of the PLGS, we will review the goal of ELP-OA and the steps to get over to bring it into play. We finally shortly described the effort in Europe to develop the LGS