Drastic effects of damping mechanisms on the third-order optical nonlinearity

We have investigated the optical response of superradiant atoms, which undergoes three different damping mechanisms: radiative dissipation ($\gamma_r$), dephasing ($\gamma_d$), and nonradiative dissipation ($\gamma_n$). Whereas the roles of $\gamma_d$ and $\gamma_n$ are equivalent in the linear susceptibility, the third-order nonlinear susceptibility drastically depends on the ratio of $\gamma_d$ and $\gamma_n$: When $\gamma_d \ll \gamma_n$, the third-order susceptibility is essentially that of a single atom. Contrarily, in the opposite case of $\gamma_d \gg \gamma_n$, the third-order susceptibility suffers the size-enhancement effect and becomes proportional to the system size.Comment: 5pages, 2figure

Ultrafast spectroscopy of single molecules

We present a single-molecule study on femtosecond dynamics in multichromophoric systems, combining fs pump-probe, emission-spectra and fluorescence-lifetime analysis. At the single molecule level a wide range of exciton delocalisation lengths and energy redistribution times is revealed. Next, two color pump-probe experiments are presented as a step to addressing ultrafast energy transfer in individual complexes

VMXR: a EUD Environment for Virtual Merchandizing in XR

This paper presents the current development state of VMXR, a Proof of Concept (PoC) environment allowing people without programming experience to create and configure product showcases in a Virtual and eXtended reality setting. The aim of the PoC is to identify proper metaphors and workflows for supporting showcase designers in creating interactions with the virtual product representation or enhancing the physical environment through additional information and media

Exploration of sex differences in Rhes effects in dopamine mediated behaviors

Studies have shown that Ras homolog enriched in striatum (Rhes) proteins are highly expressed in areas of the central nervous system that have high dopaminergic innervation. In this study, we used Rhes mutant mice (Wild type, Rhes KO, Rhes Heterozygous) of both sexes to explore differences in the effects of Rhes protein levels in basal levels of activity, anxiety, and stereotypy, in relation to sex. Adult male and female mice were evaluated in an open field test for measuring basal levels of activity and anxiety for 5 consecutive days, and they were tested in the apomorphine-induced stereotypy paradigm. Rhes protein levels affected basal levels of activity but it was not found to be related to sex differences. Moreover, a decrease in Rhes protein levels was linked to a nonsignificant anxiolytic effect, mainly in female mice. Finally, a decrease in Rhes protein levels does not affect dopamine D1 and D2 receptor (D1/D2) synergism in female or male mice. Together, these results suggest that Rhes protein levels affect locomotion activity, and have an influence in anxiety depending on sex; Rhes protein levels do not affect D1/D2 synergism in both sexes

The role of intermolecular coupling in the photophysics of disordered organic semiconductors: Aggregate emission in regioregular polythiophene

We address the role of excitonic coulping on the nature of photoexcitations in the conjugated polymer regioregular poly(3-hexylthiophene). By means of temperature-dependent absorption and photoluminescence spectroscopy, we show that optical emission is overwhelmingly dominated by weakly coupled H-aggregates. The relative absorbance of the 0-0 and 0-1 vibronic peaks provides a powerfully simple means to extract the magnitude of the intermolecular coupling energy, approximately 5 and 30 meV for films spun from isodurene and chloroform solutions respectively.Comment: 10 pages, 4 figures, published in Phys. Rev. Let

High accuracy images and range based acquiring for artistic handworks 3D-models

The research topics and the applications in the Geomatic area are often connected to the land knowledge and management or to human artefacts usually studied and analyzed from expert of other areas. When these subjects are a part of the Cultural Heritage the survey methodology for the documentation and the knowledge need to consider the final users (belong to different disciplines), in order to realize correct descriptive products suitable for all the actors involved in the preservation and the safeguard of the Cultural Heritage. During the last decade one of the important aim related to the cooperation between the Geomatics group of Politecnico di Torino and the experts working on archaeological sites is to join the new Geomatic methodology and techniques in order to realize documents and products, usable by the specialists, aimed to the archaeological site knowledge and documentation. The past applications were focused on the ancient city, from the urban scale through the archaeological evidences up till the architectural elements. The paper deal with the last experiences of the research group relating to two important archaeological objects. In particular the archaeological artefacts are figurative relief featured by small dimension, carved in the marble and belonging to two architectural elements; the subjects are two theatrical masks, one comical featured and the other tragical. In order to aid and support other analyses involving restoration strategies one of the goals of the last expedition was the documentation, the survey and modelling of the artefacts. According to the complex shape of the theatrical masks, and in order to obtain all the information requested for a correct survey documentation, a triangulation-based LiDAR system was employed (HandyScan 3D- model HZ). Moreover, since the LiDAR survey was performed on the more complex decorated surface (theatrical masks) in order to achieve a complete 3D model of the marble blocks a photogrammetric survey was realized. In the paper some topics are going to be described, highlighting advantages coming from multi-sensor data fusion techniques, both for obtaining multi-scale models and for general accuracy improvement. Some discussed topics are: The acquisition phases and the obtained results of the 3D HandyScan survey, the photogrammetric processing steps and the realized products, the assembling and integration of the different kinds of data, the 3D representation and the photorealistic modeling phases

TiO2 nanoparticles may alleviate cadmium toxicity in co-treatment experiments on the model hydrophyte Azolla filiculoides

The hydrophyte Azolla filiculoides can be a useful model to assess if TiO2 NPs may in some way alleviate the Cd injuries and improve the ability of the plant to cope with this metal. With this mechanistic hypothesis, after a pre-treatment with TiO2 NPs, A. filiculoides plants were transferred to cadmium-contaminated water with or without TiO2 nanoparticles. After 5 days of treatment, cadmium uptake, morpho-anatomical, and physiological aspects were studied in plants. The continuous presence of TiO2 nanoparticles, though not increasing the uptake of cadmium in comparison with a priming treatment, induced a higher translocation of this heavy metal to the aerial portion. Despite the translocation factor was always well below 1, cadmium contents in the fronds, generally greater than 100 ppm, ranked A. filiculoides as a good cadmium accumulator. Higher cadmium contents in leaves did not induce damages to the photosynthetic machinery, probably thanks to a compartmentalization strategy aimed at confining most of this pollutant to less metabolically active peripheral cells. The permanence of NPs in growth medium ensured a better efficiency of the antioxidant apparatus (proline and glutathione peroxidase and catalase activities) and induced a decrease in H2O2 content, but did not suppress TBARS level

Dual process in the Two-parameter Poisson-Dirichlet diffusion

The two-parameter Poisson--Dirichlet diffusion takes values in the infinite ordered simplex and has a two-parameter Poisson-Dirichlet stationary distribution ${\cal PD}(\alpha, \theta)$ . The dual process is in terms of a line-of-descent process which tracks the evolution of non-mutant frequencies from time zero, and Remarkably does not depend on the parameter $\alpha$. Methods of proof use the sampling distributions associated to the two-parameter Poisson-Dirichlet process. We also exploit a connection between the sampling distribution and a generalized Blackwell and MacQueen P{\'o}lya urn model to obtain a direct derivation of the transition density