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We present a proposal for the construction and development of a new instrument for radio astronomical observations based on interferometric techniques, that will provide high angular resolution in the 21 cm band, with the intention of improving and extending the current performance of the instruments used at the Argentine Institute of Radio Astronomy. This will allow internationally competitive scientific research and the acquisition of cutting-edge scientific and technological know-how in the aforementioned techniques, enabling interferometric measurements and the development of very long baseline or VLBI techniques. This project is called MIA, an acronym for "Multipurpose Interferometric Array".

Recently, it has been considering robotics to face world population aging. According to the WHO, in 2050 there will be about 2.1 billion people over 60 years old worldwide causing a persistent growing need of assistance and a shortage of manpower for delivering congruous assistance. Therefore, seniors' QoL is continuously threatened. Socially Assistive Robotics proposes itself as a solution. To improve SARs acceptability, it is necessary to tailor the system's characteristics with respect to the target needs and issues through the analysis of previous and current studies in the HRI field. Through the examination of the state of the art of social robotics in elderly care, past case studies and paper research about SARs' efficiency, it has been proposed two potential solution examples for two different scenarios, applying two different SARs: Pepper and Nao robots.

Fabrication of ordered structures at the nanoscale limit poses a cornerstone challenge for modern technologies. In this work we show how naturally occurring moir\'e patterns in Ir(111)-supported graphene template the formation of 2D ordered arrays of substitutional boron species. A complementary experimental and theoretical approach provides a comprehensive description of the boron species distribution, bonding configurations, interfacial interaction with Ir(111) and the impact on graphene's electronic structure. Atomically-resolved scanning tunnelling microscopy images and density functional theory calculations reveal that boron preferably forms small aggregates of substitutional defects in geometrically low regions of the moir\'e superlattice of graphene, by inducing local bending of graphene towards the underlying Ir(111). Surprisingly, calculations reveal that the incorporation of electron deficient boron does not lead to an enhanced p-type doping, as the local rippling of the graphene layer prompts electron uptake from the iridium substrate that compensates the initial electron loss due to substitutional boron. Scanning tunnelling spectroscopy and angle-resolved photoemission spectroscopy measurements corroborate that the arrays of boron species do not modify the electronic structure of graphene near the Fermi level, hence preserving the slight p-type doping induced by Ir(111)., Comment: For Supplementary materials, see https://doi.org/10.1016/j.carbon.2022.09.087

High-quality nitrogen-doped graphene on nickel is prepared by exploiting both the catalytic properties of nickel and the solubility of nitrogen atoms into its bulk. Following the standard chemical vapor deposition procedure, a previously nitrogen-doped nickel substrate is exposed to carbon-containing precursors so that nitrogen atoms, segregating to the surface, remain trapped in the growing graphene network. Morphological and chemical characterization by scanning tunneling microscopy and X-ray photoelectron spectroscopy demonstrates that the process yields a flat, wide, continuous nitrogen-doped graphene layer. Experimental results are combined with a thorough density functional theory investigation of possible structural models, to obtain a clear description at the atomic scale of the various configurations of the nitrogen atoms observed in the graphene mesh. This growth method is potentially scalable and suitable for the production of high-performance nano-devices with well-defined nitrogen centers, to be exploited as metal-free carbon-based catalysts in several applicative fields such as electrochemistry, energy storage, gas storage/sensing or wastewater treatment., Comment: 21 pages, including 4 figures, plus SI

The dynamic behavior of bundles of actin filaments growing against a loaded obstacle is investigated through a generalized version of the standard multi filaments Brownian Ratchet model in which the (de)polymerizing filaments are treated not as rigid rods but as semi-flexible discrete wormlike chains with a realistic value of the persistence length. By stochastic dynamic simulations we study the relaxation of a bundle of $N_f$ filaments with staggered seed arrangement against a harmonic trap load in supercritical conditions. Thanks to the time scale separation between the wall motion and the filament size relaxation, mimiking realistic conditions, this set-up allows us to extract a full load-velocity curve from a single experiment over the trap force/size range explored. We observe a systematic evolution of steady non-equilibrium states over three regimes of bundle lengths $L$. A first threshold length $\Lambda$ marks the transition between the rigid dynamic regime ($L<\Lambda$), characterized by the usual rigid filament load-velocity relationship $V(F)$, and the flexible dynamic regime ($L>\Lambda$), where the velocity $V(F,L)$ is an increasing function of the bundle length $L$ at fixed load $F$, the enhancement being the result of an improved level of work sharing among the filaments induced by flexibility. A second critical length corresponds to the beginning of an unstable regime characterized by a high probability to develop escaping filaments which start growing laterally and thus do not participate anymore to the generation of the polymerization force. This phenomenon prevents the bundle from reaching at this critical length the limit behavior corresponding to Perfect Load Sharing., Comment: 26 pages, 11 figures

In various cellular processes, biofilaments like F-actin and F-tubulin are able to exploit chemical energy associated to polymerization to perform mechanical work against an external load. The force-velocity relationship quantitatively summarizes the nature of this process. By a stochastic dynamical model, we give, together with the evolution of a staggered bundle of $N_f$ rigid living filaments facing a loaded wall, the corresponding force--velocity relationship. We compute systematically the simplified evolution of the model in supercritical conditions $\rho_1=U_0/W_0>1$ at $\epsilon=d^2W_0/D=0$, where $d$ is the monomer size, $D$ is the obstacle diffusion coefficient, $U_0$ and $W_0$ are the polymerization and depolymerization rates. Moreover, we see that the solution at $\epsilon=0$ is valid for a good range of small non-zero $\epsilon$ values. We consider two classical protocols: the bundle is opposed either to a constant load or to an optical trap set-up, characterized by a harmonic restoring force. The constant force case leads, for each $F$ value, to a stationary velocity $V^{stat}(F;N_f,\rho_1)$ after a relaxation with characteristic time $\tau_{micro}(F)$. When the bundle (initially taken as an assembly of filament seeds) is subjected to a harmonic restoring force (optical trap load), the bundle elongates and the load increases up to stalling (equilibrium) over a characteristic time $\tau^{OT}$. Extracted from this single experiment, the force-velocity $V^{OT}(F;N_f,\rho_1)$ curve is found to coincide with $V^{stat}(F;N_f,\rho_1)$, except at low loads. We show that this result follows from the adiabatic separation between $\tau_{micro}$ and $\tau^{OT}$, i.e. $\tau_{micro}\ll\tau^{OT}$., Comment: 19 pages, 5 figures

We establish the Statistical Mechanics framework for a bundle of Nf living and uncrosslinked actin filaments in a supercritical solution of free monomers pressing against a mobile wall. The filaments are anchored normally to a fixed planar surface at one of their ends and, because of their limited flexibility, they grow almost parallel to each other. Their growing ends hit a moving obstacle, depicted as a second planar wall, parallel to the previous one and subjected to a harmonic compressive force. The force constant is denoted as trap strength while the distance between the two walls as trap length to make contact with the experimental optical trap apparatus. For an ideal solution of reactive filaments and free monomers at fixed free monomers chemical potential, we obtain the general expression for the grand potential from which we derive averages and distributions of relevant physical quantities, namely the obstacle position, the bundle polymerization force and the number of filaments in direct contact with the wall. The grafted living filaments are modeled as discrete Wormlike chains, with Factin persistence length, subject to discrete contour length variations to model single monomer (de)polymerization steps. Rigid filaments, either isolated or in bundles, all provide average values of the stalling force in agreement with Hill's predictions, independent of the average trap length. Flexible filaments instead, for values of the trap strength suitable to prevent their lateral escape, provide an average bundle force and an average trap length slightly larger than the corresponding rigid cases (few percents). Still the stalling force remains nearly independent on the average trap length, but results from the product of two strongly L dependent contributions: the fraction of touching filaments and the single filament buckling force., Comment: 21 pages, 8 figures