95 research outputs found
Temporal properties of higher-order interactions in social networks
Human social interactions in local settings can be experimentally detected by
recording the physical proximity and orientation of people. Such interactions,
approximating face-to-face communications, can be effectively represented as
time varying social networks with links being unceasingly created and destroyed
over time. Traditional analyses of temporal networks have addressed mostly
pairwise interactions, where links describe dyadic connections among
individuals. However, many network dynamics are hardly ascribable to pairwise
settings but often comprise larger groups, which are better described by
higher-order interactions. Here we investigate the higher-order organizations
of temporal social networks by analyzing three publicly available datasets
collected in different social settings. We find that higher-order interactions
are ubiquitous and, similarly to their pairwise counterparts, characterized by
heterogeneous dynamics, with bursty trains of rapidly recurring higher-order
events separated by long periods of inactivity. We investigate the evolution
and formation of groups by looking at the transition rates between different
higher-order structures. We find that in more spontaneous social settings,
group are characterized by slower formation and disaggregation, while in work
settings these phenomena are more abrupt, possibly reflecting pre-organized
social dynamics. Finally, we observe temporal reinforcement suggesting that the
longer a group stays together the higher the probability that the same
interaction pattern persist in the future. Our findings suggest the importance
of considering the higher-order structure of social interactions when
investigating human temporal dynamics
Il voto italiano all'estero
The novelties brought in by the legislature on the Italian vote abroad marked a turning point both for Italian politics, with the introduction of foreign representation, and for the communities of Italians abroad. But what opinion do our expatriate co-nationals have of the Italian vote? And has voting from abroad brought our global co-nationals closer (or not) to Italian politics, Italy and/or their Italian heritage? And then, who are the Italians in the world? How many are there and where are they concentrated? This book offers an up-to-date reading of the experiences of the Italian vote in the world from 2003 to date, analysis of the results of a survey into the participation of Italians abroad in the 2006 political elections, as well as cues, reflections and considerations on the topic of Italian emigration and the Italian vote abroad
Temporal clustering of social interactions trades-off disease spreading and knowledge diffusion
Non-pharmaceutical measures such as preventive quarantines, remote working,
school and workplace closures, lockdowns, etc. have shown effectivenness from
an epidemic control perspective; however they have also significant negative
consequences on social life and relationships, work routines, and community
engagement. In particular, complex ideas, work and school collaborations,
innovative discoveries, and resilient norms formation and maintenance, which
often require face-to-face interactions of two or more parties to be developed
and synergically coordinated, are particularly affected. In this study, we
propose an alternative hybrid solution that balances the slowdown of epidemic
diffusion with the preservation of face-to-face interactions. Our approach
involves a two-step partitioning of the population. First, we tune the level of
node clustering, creating "social bubbles" with increased contacts within each
bubble and fewer outside, while maintaining the average number of contacts in
each network. Second, we tune the level of temporal clustering by pairing, for
a certain time interval, nodes from specific social bubbles. Our results
demonstrate that a hybrid approach can achieve better trade-offs between
epidemic control and complex knowledge diffusion. The versatility of our model
enables tuning and refining clustering levels to optimally achieve the desired
trade-off, based on the potentially changing characteristics of a disease or
knowledge diffusion process
Deformed Boost Transformations That Saturate at the Planck Scale
We derive finite boost transformations based on the Lorentz sector of the
bicross-product-basis -Poincare' Hopf albegra. We emphasize the role of
these boost transformations in a recently-proposed new relativistic theory. We
find that when the (dimensionful) deformation parameter is identified with the
Planck length, which together with the speed-of-light constant has the status
of observer-independent scale in the new relativistic theory, the deformed
boosts saturate at the value of momentum that corresponds to the inverse of the
Planck length.Comment: 6 pages, LaTex (revtex
Spin-1 resonance contributions to the weak Chiral Lagrangian: the vector field formulation
We use the Vector formulation to evaluate vector and axial-vector exchange
contributions to the O(p^4) weak Chiral Lagrangian. We recover in this
framework the bulk of the contributions found previously by Ecker et al. in the
antisymmetric formulation of vectors and axial-vectors, but new interesting
features arise: i) most of our results are independent of Factorization and ii)
novel contributions to non-leptonic kaon decays, proper of this formulation and
phenomenologically interesting, are found. The phenomenological implications
for K -> pi pi (pi) and radiative (anomalous and non-anomalous) non-leptonic
kaon decays are thus investigated and found particularly relevant.Comment: 34 pages, plain LaTeX file, uses rotating.sty also include
Venous Graft-Derived Cells Participate in Peripheral Nerve Regeneration
Background: Based on growing evidence that some adult multipotent cells necessary for tissue regeneration reside in the walls of blood vessels and the clinical success of vein wrapping for functional repair of nerve damage, we hypothesized that the repair of nerves via vein wrapping is mediated by cells migrating from the implanted venous grafts into the nerve bundle. Methodology/Principal Findings: To test the hypothesis, severed femoral nerves of rats were grafted with venous grafts from animals of the opposite sex. Nerve regeneration was impaired when decellularized or irradiated venous grafts were used in comparison to untreated grafts, supporting the involvement of venous graft-derived cells in peripheral nerve repair. Donor cells bearing Y chromosomes integrated into the area of the host injured nerve and participated in remyelination and nerve regeneration. The regenerated nerve exhibited proper axonal myelination, and expressed neuronal and glial cell markers. Conclusions/Significance: These novel findings identify the mechanism by which vein wrapping promotes nerve regeneration. © 2011 Lavasani et al
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