Ground state and excitation dynamics in Ag doped helium clusters

We present a quantum Monte Carlo study of the structure and energetics of silver doped helium clusters AgHe$_n$ for $n$ up to 100. Our simulations show the first solvation shell of the Ag atom to be composed by roughly 20 He atoms, and to possess a structured angular distribution. Moreover, the electronic $^2$P$_{1/2}\leftarrow ^2$S$_{1/2}$ and $^2$P$_{3/2}\leftarrow ^2$S$_{1/2}$ electronic transitions of the embedded silver impurity have been studied as a function of the number ofhelium atoms. The computed spectra show a redshift for $n\leq 15$ and an increasing blueshift for larger clusters, a feature attributed to the effect of the second solvation shell of He atoms. For the largest cluster, the computed excitation spectrum is found in excellent agreement with the ones recorded in superfluid He clusters and bulk. No signature of the direct formation of proposed AgHe$_2$ exciplex is present in the computed spectra of AgHe$_{100}$.Comment: 4 Pages, 3 Figures, submitted to Phys. Rev. Let

The earnest platform : U.S. presidential candidates, COVID-19, and social issues on Instagram

Increasingly, Instagram is discussed as a site for misinformation, inauthentic activities, and polarization, particularly in recent studies about elections, the COVID-19 pandemic and vaccines. In this study, we have found a different platform. By looking at the content that receives the most interactions over two time periods (in 2020) related to three U.S. presidential candidates and the issues of COVID-19, healthcare, 5G and gun control, we characterize Instagram as a site of earnest (as opposed to ambivalent) political campaigning and moral support, with a relative absence of polarizing content (particularly from influencers) and little to no misinformation and artificial amplification practices. Most importantly, while misinformation and polarization might be spreading on the platform, they do not receive much user interaction

Visual Geolocations. Repurposing online data to design alternative views

Data produced by humans and machines is more and more heterogeneous, visual, and location based. This availability inspired in the last years a number of reactions from researchers, designers, and artists that, using different visual manipulations techniques, have attempted at repurposing this material to add meaning and design new perspectives with specific intentions. Three different approaches are described here: the design of interfaces for exploring satellite footage in novel ways, the analysis of urban esthetics through the visual manipulation of collections of user-generated contents, and the enrichment of geo-based datasets with the selection and rearrangement of web imagery

Un-indexing forest media: repurposing search query results to reconsider forest-society relations

Geographical research is increasingly focused on how digital technology shapes human-nature relations. This article explores how internet search engines and their associated algorithms and indexing technologies order and produce homogenising accounts of forest places. We put forward ‘un-indexing’ as a critical and inventive method for un-ordering and re-ordering search engine results to complicate digital perspectives on forest-society relations. We present Everything at the Forest Park, a series of four speculative catalogues we created to invite collective inquiries into the digital mediation of a forested area in Scotland – Queen Elizabeth Forest Park. Fostering a slower form of engagement with web material, the catalogues suggest how geographers and other scholars might critically repurpose, reappropriate and interrogate the algorithmically curated and advertising-oriented orderings of search engines to foster more careful and convivial forest-society relations

Thermal boundary resistance from transient nanocalorimetry: a multiscale modeling approach

The Thermal Boundary Resistance at the interface between a nanosized Al film and an Al_{2}O_{3} substrate is investigated at an atomistic level. A room temperature value of 1.4 m^{2}K/GW is found. The thermal dynamics occurring in time-resolved thermo-reflectance experiments is then modelled via macro-physics equations upon insertion of the materials parameters obtained from atomistic simulations. Electrons and phonons non-equilibrium and spatio-temporal temperatures inhomo- geneities are found to persist up to the nanosecond time scale. These results question the validity of the commonly adopted lumped thermal capacitance model in interpreting transient nanocalorimetry experiments. The strategy adopted in the literature to extract the Thermal Boundary Resistance from transient reflectivity traces is revised at the light of the present findings. The results are of relevance beyond the specific system, the physical picture being general and readily extendable to other heterojunctions.Comment: 12 pages, 8 figure

L'ITALIANO PER CAPIRE

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L'ITALIANO PER CAPIRE

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Mapping of Asbestos Cement Roofs and Their Weathering Status Using Hyperspectral Aerial Images

and (ii) the development of a spectral index related to the roof weathering status. Aerial images were collected through the Multispectral Infrared and Visible Imaging Spectrometer (MIVIS) sensor, which acquires data in 102 channels from the visible to the thermal infrared spectral range. An image based supervised classification was performed using the Spectral Angle Mapper (SAM) algorithm. The SAM was trained through a set of pixels selected on roofs of different materials. The map showed an average producer's accuracy (PA) of 86% and a user's accuracy (UA) of 89% for the asbestos cement class. A novel spectral index, the "Index of Surface Deterioration" (ISD), was defined based on measurements collected with a portable spectroradiometer on asbestos cement roofs that were characterized by different weathering statuses. The ISD was then calculated on the MIVIS images, allowing the distinction of two weathering classes (i.e., high and low). The asbestos cement map was handled in a Geographic Information System (GIS) in order to supply the municipalities with the cadastral references of each property having an asbestos cement roof. This tool can be purposed for municipalities as an aid to prioritize asbestos removal, based on roof weathering status