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

Design artefacts as exploratory tools of Urban Biodiversity debates: eight case studies on Milan

The poster demonstrates methods to map and communicate debates about urban biodiversity in Milan. Advocating for urban biodiversity through dedicated policies has become a necessity in our increasingly urbanized environment. However, this process is not without its challenges: What happens when these policies impact a relatively small area and group of people? What reactions do they provoke? How can we gauge the extent of the debate? The research was guided by the theoretical framework of Digital Methods and Issue Mapping. We used various web platforms as a lens to delve into the dynamics of a portion of the debate. This included analyzing the most viewed YouTube videos, images used by online media outlets, comments on Facebook, and transcripts of municipal meetings. The research focused on eight hyper-local debates in the city of Milan: the construction of the Olympic village; the redevelopment of La Goccia, a former industrial area north of Milan; the future of Piazza d'Armi in Baggio; the maintenance of Milan parks; the Forestami reforestation project; the regeneration of via Pacini; the wisteria of Piazza Baiamonti; and the wood of via Falck. Information design and data visualization approaches were employed to develop informative artifacts that were later displayed in a public exhibition. The research allowed for an analysis of how various debates are structured around the theme of urban biodiversity: the most used terms, citizens' fears and expectations, the linguistic variety of different political positions on the issue, and the identification of the role of urban biodiversity in collective perception

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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