Modeling the electrooptic evolution in thermally poledgermanosilicate fibers

We formulate a simple quantitative three-species charge-carrier transport model, consisting of two distinct positive ions and a single negative ion, to describe the dynamics during thermal poling of a germanosilicate optical fiber. We numerically solved the equations and report one-dimensional space-time solutions for the electrooptic (EO) coefficient. In the two-cation model, our findings show the EO coefficient initially dips near the anode and then monotonically rises to a steady-state value, higher than that produced by the initial applied poling field. However, at the cathode, the electric field quickly dropped to zero where it remained zero for the poling duration. The introduction of a moving negative ion clearly shows the existence of a dead time characteristic appearing at the cathode, resulting in a gain in the initial EO coefficient. This model also reveals that the resulting EO evolution in a thermally poled germanium-boron codoped fiber can he attributed to the movement of just two ions of opposite polarity. To explain the increase in the EO coefficient in boron codoped germanosilicate fiber, we found it necessary to allow for an increase in the third-order susceptibility by a factor of ~3.4     

Landscape fragmentation and urban sprawl in the urban region of Milan

Spatial expansion of cities appears to be unavoidable. Despite concern around landscape alterations caused by urban expansion, the understanding of the amounts and patterns of this phenomenon is sorely lacking. In this study, we quantified the current pattern of landscape fragmentation in the urban region (UR) of Milan and analysed the trend of urban sprawl over more than 50 years. The UR of Milan was spatially defined using a standardised and repeatable methodology that combines land-use and population density data. Fragmentation was assessed using the effective mesh size (m_eff). The trend of sprawl was monitored between 1954 and 2012 and over different areas to detect the magnitude (amount and direction) and patterns of changes. Results revealed a positive trend and a high degree of sprawl over the whole study area.     

The HEPD particle detector of the CSES satellite mission for investigating seismo-associated perturbations of the Van Allen belts

CSES(China Seismo-Electromagnetic Satellite) is a mission developed by CNSA(Chinese National Space Administration) and ASI(Italian Space Agency), to investigate the near-Earth electromagnetic, plasma and particle environment, for studying the seismo-associated disturbances in the ionosphere-magnetosphere transition zone. The anthropogenic and electromagnetic noise,as well as the natural non-seismic electromagnetic emissions is mainly due to tropospheric activity. In particular, the mission aims to confirming the existence of possible temporal correlations between the occurrence of earthquakes for medium and strong magnitude and the observation in space of electromagnetic perturbations, plasma variations and precipitation of bursts with highenergy charged particles from the inner Van Allen belt. In this framework, the high energy particle detector(HEPD) of the CSES mission has been developed by the Italian LIMADOU Collaboration. HEPD is an advanced detector based on a tower of scintillators and a silicon tracker that provides good energy and angular resolution and a wide angular acceptance, for electrons of 3–100 Me V, protons of 30–200 Me V and light nuclei up to the oxygen. CSES satellite has been launched on February 2~(nd), 2018 from the Jiuquan Satellite Launch Center(China).     

A hybrid inductive learning-based and deductive reasoning-based 3-D path planning method in complex environments

Autonomous Robots - Traditional path planning methods, such as sampling-based and iterative approaches, allow for optimal path’s computation in complex environments. Nonetheless, environment...     

Multiphase Flow in Deforming Porous Media: A Review

In this work we present a general model for the analysis of multiphase flow in deforming porous media with particular regard to concrete and biological tissues. Such problems are typically multi-physics ones with overlapping domains where diffusion, advection, adsorption, phase change, deformation, chemical reactions and other phenomena take place in the porous medium. For the analysis of such a complex system, the model here proposed is obtained from microscopic scale by applying the thermodynamically constrained averaging theory which guarantees the satisfaction of the second law of thermodynamics for all constituents both at micro and macro-level. Furthermore, one can obtain some important thermodynamic restrictions for the evolution equations describing the material deterioration. Two specific forms of the general model adapted to the cases of cementitious and biological materials respectively are shown. Some numerical simulations aimed at proving the validity of the approach adopted, are also presented and discussed.     

Exploring the Role of Genetic Variability and Lifestyle in Oxidative Stress Response for Healthy Aging and Longevity

Oxidative stress is both the cause and consequence of impaired functional homeostasis characterizing human aging. The worsening efficiency of stress response with age represents a health risk and leads to the onset and accrual of major age-related diseases. In contrast, centenarians seem to have evolved conservative stress response mechanisms, probably derived from a combination of a diet rich in natural antioxidants, an active lifestyle and a favorable genetic background, particularly rich in genetic variants able to counteract the stress overload at the level of both nuclear and mitochondrial DNA. The integration of these factors could allow centenarians to maintain moderate levels of free radicals that exert beneficial signaling and modulator effects on cellular metabolism. Considering the hot debate on the efficacy of antioxidant supplementation in promoting healthy aging, in this review we gathered the existing information regarding genetic variability and lifestyle factors which potentially modulate the stress response at old age. Evidence reported here suggests that the integration of lifestyle factors (moderate physical activity and healthy nutrition) and genetic background could shift the balance in favor of the antioxidant cellular machinery by activating appropriate defense mechanisms in response to exceeding external and internal stress levels, and thus possibly achieving the prospect of living a longer life.     

The role of inventors’ networks and variety for breakthrough inventions

This paper studies the role of the inventors’ networks and the diversity of the local industrial structure for regional innovation, differentiating between regions' production of normal and breakthrough innovations. Our results suggest that, on the one hand, local related variety enhances the overall innovation rate, while unrelated variety supports the rate of breakthrough innovations. On the other hand, we find evidence that inventors’ networks are determinant for regions' patenting of normal and breakthrough innovations. To do so we constructed a unique database of Italian patenting activity at the United States Patent and Trademark Office (USPTO) dating back to 1972.