Improving image contrast in fluorescence microscopy with nanostructured substrates

Metallic and dielectric nanostructures can show sharp contrastedresonances, sensitive to the environment, and high field enhancement insub-wavelength volumes. For this reason, these structures are commonlyused as molecular sensors. Only few works have focused on theirapplication in optical microscopy, in particular in superresolution. In thiswork we have designed, fabricated and optically tested a nanostructuredTiO2 substrate, fabricated by direct embossing of TiO2 derived film, as asubstrate for fluorescence microscopy. Moreover, using numericalsimulations, we have compared the signal to background noise with respectto other metallo-dielectric structures. We show that the TiO2 structure is agood candidate for reducing the thickness of the fluorescence excitationdown to ~100 nm. Therefore, this substrate can be used to obtain TotalInternal Reflection (TIRF) axial resolution without a TIRF-Microscopysystem.Fil: Brunstein, Maia. Centre National de la Recherche Scientifique; Francia. Université Paris-Saclay; FranciaFil: Cattoni, Andrea. Centre National de la Recherche Scientifique; Francia. Université Paris-Saclay; FranciaFil: Estrada, Laura Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Yacomotti, Alejandro M.. Centre National de la Recherche Scientifique; Francia. Université Paris-Saclay; Franci

Atmospheric drying as the main driver of dramatic glacier wastage in the southern Indian Ocean

This study was funded by IPEV-1048 GLACIOCLIM-KESAACO and LEFE-INSU KCRuMBLE programs, and the Agence Nationale de la Recherche through contract ANR-14-CE01-0001-01 (ASUMA).The ongoing retreat of glaciers at southern sub-polar latitudes is particularly rapid and widespread. Akin to northern sub-polar latitudes, this retreat is generally assumed to be linked to warming. However, no long-term and well-constrained glacier modeling has ever been performed to confirm this hypothesis. Here, we model the Cook Ice Cap mass balance on the Kerguelen Islands (Southern Indian Ocean, 49°S) since the 1850s. We show that glacier wastage during the 2000s in the Kerguelen was among the most dramatic on Earth. We attribute 77% of the increasingly negative mass balance since the 1960s to atmospheric drying associated with a poleward shift of the mid-latitude storm track. Because precipitation modeling is very challenging for the current generation of climate models over the study area, models incorrectly simulate the climate drivers behind the recent glacier wastage in the Kerguelen. This suggests that future glacier wastage projections should be considered cautiously where changes in atmospheric circulation are expected.Publisher PDFPeer reviewe

Exploring alternative symmetry breaking mechanisms at the LHC with 7, 8 and 10 TeV total energy

In view of the annnouncement that in 2012 the LHC will run at 8 TeV, we study the possibility of detecting signals of alternative mechanisms of ElectroWeak Symmetry Breaking, described phenomenologically by unitarized models, at energies lower than 14 TeV. A complete calculation with six fermions in the final state is performed using the PHANTOM event generator. Our results indicate that at 8 TeV some of the scenarios with TeV scale resonances are likely to be identified while models with no resonances or with very heavy ones will be inaccessible, unless the available luminosity will be much higher than expected

Adolescents’ viewing of suicide-related web content and psychological problems: differentiating the roles of cyberbullying involvement

Possible links of cyberbullying with suicide and psychological problems have recently received considerable attention. Suicide-related behaviours have also been linked with viewing of associated web-content. Studies on traditional bullying indicate that the roles of bullying involvement (bullies, victims and bully-victims) matter in terms of associations with specific suicide-related behaviours and psychological problems. Yet, related research in the area of cyberbullying is lacking. The current study investigates the association of cyberbullying roles with viewing of specific suicide-related web-content and psychological problems. Data from N = 19,406 (50% girls) 11-16 year olds (M = 13.54, SD = 1.68) of a representative sample of internet using children in Europe were analysed. Self- reports were obtained for cyberbullying role, viewing of web-content related to self-harm and suicide as well as the emotional, peer and conduct problems subscales of the Strength and Difficulties Questionnaire (SDQ). Multi-nomial logistic regression analyses revealed that compared to those not involved in cyberbullying, viewing of web-content related to suicide was higher for cybervictims and cyberbully-victims but not for cyberbullies. Viewing of web-content related to self-harm was higher for all cyberbullying roles but especially for cyberbully-victims. Rates of emotional problems were higher among cybervictims and cyberbully-victims, rates of peer problems were higher for cybervictims, and rates of conduct problems were higher for all cyberbullying roles. Moreover, the links between cyberbullying role and viewing of suicide-related web-content were independent of psychological problems. The results can be useful to more precisely target efforts towards the specific problems of each cyberbullying role. The outcomes on viewing of web-content also indicate an opportunity to enhance the presence of health service providers on internet platforms

Corrections to Scaling for the Two-dimensional Dynamic XY Model

With large-scale Monte Carlo simulations, we confirm that for the two-dimensional XY model, there is a logarithmic correction to scaling in the dynamic relaxation starting from a completely disordered state, while only an inverse power law correction in the case of starting from an ordered state. The dynamic exponent $z$ is $z=2.04(1)$.Comment: to appear as a Rapid commu. in Phys. Rev.