A Cascade Neural Network Architecture investigating Surface Plasmon Polaritons propagation for thin metals in OpenMP

Surface plasmon polaritons (SPPs) confined along metal-dielectric interface have attracted a relevant interest in the area of ultracompact photonic circuits, photovoltaic devices and other applications due to their strong field confinement and enhancement. This paper investigates a novel cascade neural network (NN) architecture to find the dependance of metal thickness on the SPP propagation. Additionally, a novel training procedure for the proposed cascade NN has been developed using an OpenMP-based framework, thus greatly reducing training time. The performed experiments confirm the effectiveness of the proposed NN architecture for the problem at hand

Measurements of the Complex Conductivity of NbxSi1-x Alloys on the Insulating Side of the Metal-Insulator Transition

We have conducted temperature and frequency dependent transport measurements in amorphous Nb_x Si_{1-x} samples in the insulating regime. We find a temperature dependent dc conductivity consistent with variable range hopping in a Coulomb glass. The frequency dependent response in the millimeter-wave frequency range can be described by the expression $sigma(omega) \propto (-\imath omega)^alpha$ with the exponent somewhat smaller than one. Our ac results are not consistent with extant theories for the hopping transport.Comment: 4 pages with 3 figures; published version has a different title from original (was: "Electrodynamics in a Coulomb glass"

Polaronic optical absorption in electron-doped and hole-doped cuprates

Polaronic features similar to those previously observed in the photoinduced spectra of cuprates have been detected in the reflectivity spectra of chemically doped parent compounds of high-critical-temperature superconductors, both $n$-type and $p$-type. In Nd$_2$CuO$_{4-y}$ these features, whose intensities depend both on doping and temperature, include local vibrational modes in the far infrared and a broad band centered at $\sim$ 1000 cm$^{-1}$. The latter band is produced by the overtones of two (or three) local modes and is well described in terms of a small-polaron model, with a binding energy of about 500 cm$^{-1}$. Most of the above infrared features are shown to survive in the metallic phase of Nd$_{2-x}$Ce$_x$Cu0$_{4-y}$, Bi$_2$Sr$_2$CuO$_6$, and YBa$_2$Cu$_3$O$_{7-y}$, where they appear as extra-Drude peaks. The occurrence of polarons is attributed to local modes strongly coupled to carriers, as shown by a comparison with tunneling results.Comment: File latex, 31 p., submitted to Physical Review B. Figures may be faxed upon reques

Analysis of HVSR Data Using a Modified Centroid-Based Algorithm for Near-Surface Geological Reconstruction

Recently, the use of microtremor techniques for subsoil investigation has increased significantly. The HVSR (Horizontal to Vertical Spectral Ratio) technique allows, in many cases, to obtain a seismo-stratigraphic reconstruction of the subsoil and to identify areas with similar seismic behavior. However, the stratigraphic interpretation of the HVSR peaks still remains a subjective choice and linked to a priori information. A non-hierarchical centroid-based algorithm was modified to group HVSR peaks of different measurements that can be attributed to the same generating seismic discontinuity. Some tests performed have shown that the proposed algorithm produces valid results even in the absence of a priori information to evaluate the choice of the optimal grouping. The results obtained for HVSR measurements acquired in the city of Modica (Italy) are presented. The cluster analysis of these data and the information on the lithologies outcropping in the area made it possible to reconstruct a 3D model of the main seismo-stratigraphic discontinuities

Whole-brain histogram and voxel-based analyses of apparent diffusion coefficient and magnetization transfer ratio in celiac disease, epilepsy, and cerebral calcifications syndrome

BACKGROUND AND PURPOSE: Diffusion and magnetization transfer (MT) techniques have been applied to the investigation with MR of epilepsy and have revealed changes in patients with or without abnormalities on MR imaging. We hypothesized that also in the coeliac disease (CD), epilepsy and cerebral calcifications (CEC) syndrome diffusion and MT techniques could reveal brain abnormalities undetected by MR imaging and tentatively correlated to epilepsy. MATERIALS AND METHODS: Diffusion and MT weighted images were obtained in 10 patients with CEC, 8 patients with CD without epilepsy and 17 healthy volunteers. The whole brain apparent diffusion coefficient (ADC) and MT ratio (MTR) maps were analyzed with histograms and the Statistical Parametric Mapping 2 (SPM2) software. We employed the non-parametric Mann-Whitney U test to assess differences for ADC and MTR histogram metrics. Voxel by voxel comparison of the ADC and MTR maps was performed with 2 tails t-test corrected for multiple comparison. RESULTS: A significantly higher whole brain ADC value as compared to healthy controls was observed in CEC (P = 0.006) and CD (P = 0.01) patients. SPM2 showed bilateral areas of significantly decreased MTR in the parietal and temporal subcortical white matter (WM) in the CEC patients. CONCLUSION: Our study indicates that diffusion and MT techniques are also capable of revealing abnormalities undetected by MR imaging. In particular patients with CEC syndrome show an increase of the whole brain ADC histogram which is more pronounced than in patients with gluten intolerance. IN CEC patients, voxel-based analysis demonstrates a localized decrease of the MTR in the parieto-temporal subcortical WM

The role of venture capital and private equity for innovation and development of SMEs : evidence from Italian puzzle

Numerous studies have discussed that even if fundamental for innovation and economic growth, SMEs are often financially more constrained than large firms. Therefore, venture capitalists are often the only available sources of financing to small and young companies. Through the analysis of a database that includes 160 funding deals signed in Italy, we research for empirical evidence of the determinants and effects of VC and PE investments. We find that VC and PE funds are more likely to finance younger and smaller firms. We confirm the presence of the certification effect under new circumstances applying to SMEs

Does corporate governance really matter for firms performance? Evidence from Italian IPOS market

During recent years, corporate governance has received an increasing attention in the academic debate due to several scandals in financial world and consequent changes in the regulatory framework. Through this paper, we aim to take part in the stimulating debate about the relation between corporate governance and performance. Previous literature on this topic provided a solid theoretical framework for our research. This paper contributes to this investigation with an analysis of the Italian market, by the examination of the relation between the market performance of Italian IPOs and their governance structure. In particular, we find evidence of a positive relation between governance, which we measured by a new and original governance index made by 40 provisions, and IPOs performance occurred in the Italian market during period 1998-2008

Investigating the Internal Deterioration of the Auriga Statue of Mozia Island, Sicily, through Ultrasonic and Ground-Penetrating Radar Studies

The Greek marble statue of the Auriga of Mozia Island, in Sicily, is the most important artwork displayed at the Whitaker Foundation Archaeological Museum. It underwent geophysical investigations twice, in 2012 and 2021, to assess the marble’s degradation. The 2012 investigation prepared the statue for transfer to the Paul Getty Museum in New York and repositioning on an anti-seismic pedestal. The 2021 investigation evaluated potential new damage before another transfer. Both investigations utilized 3D ultrasonic tomography (UST) to detect degraded marble areas and ground-penetrating radar (GPR) to identify internal discontinuities, such as fractures or lesions, and locate metal pins that were previously inserted to reassemble the statue and its pedestal. Results from the UST indicate an average marble velocity of approximately 4700 m/s, suggesting good mechanical strength, with some areas showing lower velocities (~3000 m/s) within the material’s variability range. The GPR profiles demonstrated internal signal homogeneity, excluding internal fracture surfaces or lesions, and confirmed the presence of metallic pins. This study highlights the effectiveness of integrating UST and GPR for non-invasive diagnostics of marble sculptures, providing detailed insights into the marble’s condition and identifying hidden defects or damage

Estimating rodent losses to stored rice as a means to assess efficacy of rodent management

Context: Post-harvest losses by rodents have traditionally been calculated by estimates of consumption determined in the laboratory. Methods for assessing storage losses by rodents under smallholder conditions will help farmers and policy makers understand the impact rodents may have on food security, nutrition and health. Stored product loss assessment methods could also be used to monitor the effects of rodent control in villages. Aims: The present study examined a method to measure the amount of rice eaten by rodents in household granaries. The effects of trapping and better hygiene around granaries to reduce rodent populations were investigated using the post-harvest monitoring method to determine whether the program was successful in lowering rodent numbers sufficiently to reduce post-harvest losses. Methods: Baskets with known quantities of rice were placed within household granaries and monitored periodically for moisture content, weight loss, faecal contamination and percentage of rodent-damaged grains. Using an empirical treatment–control study, rodent management was performed at the community level through daily trapping in two Bangladesh villages and in Myanmar at the granary storehouse level. Post-harvest losses were monitored in granaries in villages with rodent management and in similar granaries in villages where there was no management. Key results: Estimates of household losses in the absence of rodent control were 2.5% in Bangladesh and 17% in Myanmar. These losses were reduced when rodent control was implemented, down to 0.5% in Bangladesh and 5% in Myanmar. Conclusions: The impact of rodents on smallholder storage can be accurately assessed in the field under realistic conditions. Intensive daily trapping at the community level together with improved hygiene practices can successfully reduce rodent numbers, and this can significantly reduce stored grain losses and rodent contamination and damage levels. Implications: In addition to the threat of rodent pests during crop production, rodents are a major threat to food security after harvest and have, as of yet, unquantified impacts on household nutrition and health through potential transmission of gastroenteric diseases and zoonoses to householders and domestic livestock. Trapping and environmental management are affordable and effective tools to reduce rodent impacts on stored grain within communities and are viable alternatives to rodenticides