3,506 research outputs found
Increasing Geoheritage Awareness through Non-Formal Learning
Non-formal learning can have a crucial role in increasing citizens’ literacy to geoscience providing the opportunity to raise the public profile of geology and geomorphology. Starting from these remarks, the project presented here is one of the first attempts, at national level, aimed at achieving the territorial upgrading based on geoheritage enhancement. The project started thanks to a bottom-up input and involved the collaboration between scholars and local administrations and stakeholders for the valorization of a fluvial area within the Municipality of Castellarano (Emilia Apennines, Northern Italy). To achieve this aim of non-formal learning activities, based on the interpretation of the geoheritage, have been implemented. In fact, the investigated area includes valuable geological and geomorphological features which have been used, in the frame of the project here presented, to promote local geodiversity and geotourism. In particular, three geosites of regional significance were considered for the creation of EarthCaches, interpretative panels and guided excursions. Interpretative contents were designed to be educational, providing accurate but non-technical explanations. Attention was given in including illustrations playing an important role in the learning process. The results revealed that the implemented activities positively contribute to raising public awareness on the value of geoheritage
Resonant optical second harmonic generation in graphene-based heterostructures
An optical Second-Harmonic Generation (SHG) allows to probe various
structural and symmetry-related properties of materials, since it is sensitive
to the inversion symmetry breaking in the system. Here, we investigate the SHG
response from a single layer of graphene disposed on an insulating hexagonal
Boron Nitride (hBN) and Silicon Carbide (SiC) substrates. The considered
systems are described by a non-interacting tight-binding model with a mass
term, which describes a non-equivalence of two sublattices of graphene when the
latter is placed on a substrate. The resulting SHG signal linearly depends on
the degree of the inversion symmetry breaking (value of the mass term) and
reveals several resonances associated with the band gap, van Hove singularity,
and band width. The difficulty in distinguishing between SHG signals coming
from the considered heterostrusture and environment (insulating substrate) can
be avoided applying a homogeneous magnetic field. The latter creates Landau
levels in the energy spectrum and leads to multiple resonances in the SHG
spectrum. Position of these resonances explicitly depends on the value of the
mass term. We show that at energies below the band-gap of the substrate the SHG
signal from the massive graphene becomes resonant at physically relevant values
of the applied magnetic field, while the SHG response from the environment
stays off-resonant
CROSSalive: A web server for predicting the in vivo structure of RNA molecules
Motivation: RNA structure is difficult to predict in vivo due to interactions with enzymes and other molecules. Here we introduce CROSSalive, an algorithm to predict the single-and double-stranded regions of RNAs in vivo using predictions of protein interactions. Results: Trained on icSHAPE data in presence (m6a+) and absence of N6 methyladenosine modification (m6a-), CROSSalive achieves cross-validation accuracies between 0.70 and 0.88 in identifying high-confidence single-and double-stranded regions. The algorithm was applied to the long non-coding RNA Xist (17 900 nt, not present in the training) and shows an Area under the ROC curve of 0.83 in predicting structured regions
Zooming in on protein–RNA interactions: a multilevel workflow to identify interaction partners
Interactions between proteins and RNA are at the base of numerous cellular regulatory and functional phenomena. The investigation of the biological relevance of non-coding RNAs has led to the identification of numerous novel RNA-binding proteins (RBPs). However, defining the RNA sequences and structures that are selectively recognised by an RBP remains challenging, since these interactions can be transient and highly dynamic, and may be mediated by unstructured regions in the protein, as in the case of many non-canonical RBPs. Numerous experimental and computational methodologies have been developed to predict, identify and verify the binding between a given RBP and potential RNA partners, but navigating across the vast ocean of data can be frustrating and misleading. In this mini-review, we propose a workflow for the identification of the RNA binding partners of putative, newly identified RBPs. The large pool of potential binders selected by in-cell experiments can be enriched by in silico tools such as catRAPID, which is able to predict the RNA sequences more likely to interact with specific RBP regions with high accuracy. The RNA candidates with the highest potential can then be analysed in vitro to determine the binding strength and to precisely identify the binding sites. The results thus obtained can furthermore validate the computational predictions, offering an all-round solution to the issue of finding the most likely RNA binding partners for a newly identified potential RBP
Impact of partially bosonized collective fluctuations on electronic degrees of freedom
In this work we present a comprehensive analysis of collective electronic
fluctuations and their effect on single-particle properties of the Hubbard
model. Our approach is based on a standard dual fermion/boson scheme with the
interaction truncated at the two-particle level. Within this framework we
compare various approximations that differ in the set of diagrams (ladder vs
exact diagrammatic Monte Carlo), and/or in the form of the four-point
interaction vertex (exact vs partially bosonized). This allows to evaluate the
effect of all components of the four-point vertex function on the electronic
self-energy. In particular, we observe that contributions that are not
accounted for by the partially bosonized approximation for the vertex have only
a minor effect on electronic degrees of freedom in a broad range of model
parameters. In addition, we find that in the regime, where the ladder dual
fermion approximation provides an accurate solution of the problem, the leading
contribution to the self-energy is given by the longitudional bosonic modes.
This can be explained by the fact that contributions of transverse
particle-hole and particle-particle modes partially cancel each other. Our
results justify the applicability of the recently introduced dual triply
irreducible local expansion (D-TRILEX) method that represents one of the
simplest consistent diagrammatic extensions of the dynamical mean-field theory.
We find that the self-consistent D-TRILEX approach is reasonably accurate also
in challenging regimes of the Hubbard model, even where the dynamical
mean-field theory does not provide the optimal local reference point (impurity
problem) for the diagrammatic expansion
Extended regime of coexisting metallic and insulating phases in a two-orbital electronic system
We investigate the metal-to-insulator phase transition driven by electronic
interactions in the quarter-filled Hubbard-Kanamori model on a cubic lattice
with two orbitals split by a crystal field. We show that a systematic
consideration of the non-local collective electronic fluctuations strongly
affects the state-of-the-art picture of the phase transition provided by the
dynamical mean field theory. Our calculations reveal a region of phase
coexistence between the metallic and the Mott insulating states, which is
missing in the local approximation to electronic correlations. This coexistence
region is remarkably broad in terms of the interaction strength. It starts at a
critical value of the interaction slightly larger than the bandwidth and
extends to more than twice the bandwidth, where the two solutions merge into a
Mott insulating phase. Our results illustrate that non-local correlations can
have crucial consequences on the electronic properties in the strongly
correlated regime, even in the simplest multi-orbital systems
Multi-band D-TRILEX approach to materials with strong electronic correlations
We present the multi-band dual triply irreducible local expansion (D-TRILEX) approach to interacting electronic systems and discuss its numerical implementation. This method is designed for a self-consistent description of multi-orbital systems that can also have several atoms in the unit cell. The current implementation of the D-TRILEX approach is able to account for the frequency- and channel-dependent long-ranged electronic interactions. We show that our method is accurate when applied to small multi-band systems such as the Hubbard-Kanamori dimer. Calculations for the extended Hubbard, the two-orbital Hubbard-Kanamori, and the bilayer Hubbard models are also discussed
Geomorphology of the north-eastern coast of Gozo (Malta, Mediterranean Sea)
The paper presents a geomorphological map of the north-eastern coast of the Island of Gozo (Malta) integrating inland and offshore areas at the scale 1:15,000. The map derives from the integration of different methods, such as aerial photo interpretation, field surveys and analysis of seafloor bathymetry. The landforms identified on land were shaped by coastal, fluvial, karst and gravity-induced processes, and some of them prolong on the seafloor. Most of the submerged landforms appear to have been modelled in subaerial conditions during sea-level lowstands, having been sealed by the rising sea in post-glacial times. Two sketches accompany the Main Map showing the type and distribution of coastal geomorphotypes and the land cover of the area
Direct Observation of Incommensurate–Commensurate Transition in Graphene-hBN Heterostructures via Optical Second Harmonic Generation
Commensurability effects play a crucial role in the formation of electronic properties of novel layered heterostructures. The interest in these moiré superstructures has increased tremendously since the recent observation of a superconducting state (Nature 2018, 556, 43–50) and metal–insulator transition (Nature 2018, 556, 80–84) in twisted bilayer graphene. In this regard, a straightforward and efficient experimental technique for detection of the alignment of layered materials is desired. In this work, we use optical second harmonic generation, which is sensitive to the inversion symmetry breaking, to investigate the alignment of graphene/hexagonal boron nitride heterostructures. To achieve that, we activate a commensurate–incommensurate phase transition by a thermal annealing of the sample. We find that this structural change in the system can be directly observed via a strong modification of a nonlinear optical signal. Unambiguous interpretation of obtained results reveals the potential of a second harmonic generation technique for probing of structural changes in layered systems
New development: Directly elected mayors in Italy: creating a strong leader doesn’t mean creating strong leadership
More than 20 years after their introduction, directly elected mayors are key players in Italian urban governance. This article explains the main effects of this reform on local government systems and provides lessons for other countries considering directly elected mayors
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