Probing cosmological parameters with GRBs

In light of the recent finding of the narrow clustering of the geometrically-corrected gamma-ray energies emitted by Gamma Ray Bursts (GRBs), we investigate the possibility to use these sources as standard candles to probe cosmological parameters such as the matter density Omega_m and the cosmological constant energy density Omega_Lambda. By simulating different samples of gamma-ray bursts, based on recent observational results, we find that Omega_m (with the prior Omega_m + Omega_Lambda = 1) can be determined with accuracy ~7% with data from 300 GRBs, provided a local calibration of the standard candles be achieved.Comment: 4 pages, 2 figures, to appear in the Proceedings of the Conference "30 Years of GRB Discovery", Santa Fe, New Mexico, USA, September 8-12, 200

Nellix endovascular aortic sealing endoprosthesis late explantation for concomitant type I endoleak and stent frames proximal caudal migration

Endovascular aneurysm sealing (EVAS) using the Nellix™ System was introduced in clinical practice with the aim of reducing the incidence of complications such as migration, endoleaks, and reinterventions after conventional endovascular aneurysm repair (EVAR). Although, initial efficacy data on this device have been encouraging, EVAS has also demonstrated to undergo adverse events. Herein, we report a case of Nellix graft explant due to endobags shrinkage after air bubble reabsorption leading to proximal type I A endoleak and stent migration. The focus of this article is on the importance of a more assiduous surveillance of this new device, in particular in those cases with air into the endobags immediately after the procedure; this surveillance should be aimed to timely identify complications which can otherwise lead to consequences that require open conversion

The Historical Development of the Port of Livorno (Italy) and Its New Port Plan 2010 in Advanced Stage of Elaboration

The geographical location makes the port of Livorno one of the most important in Italy. The port, in fact, benefits of an extended network of roads and rails connecting it with the rest of Italy, and central and southern Europe as well. The history of Livorno and its port is inextricably linked to that of Pisa and Florence, and to the complexity of events that determined the political set-up of the region along several centuries. Looking at the new port plan of Livorno has made it necessary an extensive overview of the history of both the port, and of its planning. This analysis has allowed: to understand the reason for the different choices made in the past for the development of the port, highlighting, when necessary, the errors made; to identify the strengths and weaknesses of the existing port infrastructure; to identify the works needed to boost the port in the European context. The purpose of this paper is to provide a summary of the analysis performed for the implementation of the new Livorno port plan 2010 and show how the port planning in Italy is often conditioned by hundreds of centuries of history

Numerical and Physical Modeling of Ponte Liscione (Guardialfiera, Molise) Dam Spillways and Stilling Basin

Issues such as the design or reauditing of dams due to the occurrence of extreme events caused by climatic change are mandatory to address to ensure the safety of territories. These topics may be tackled numerically with Computational Fluid Dynamics and experimentally with physical models. This paper describes the 1:60 Froude-scaled numerical model of the Liscione (Guardialfiera, Molise, Italy) dam spillway and the downstream stilling basin. The k-omega SST turbulence model was chosen to close the Reynolds-averaged Navier-Stokes equations (RANS) implemented in the commercial software Ansys Fluent(R). The computation domain was discretized using a grid with hexagonal meshes. Experimental data for model validation were gathered from the 1:60 scale physical model of the Liscione dam spillways and the downstream riverbed of the Biferno river built at the Laboratory of Hydraulic and Maritime Constructions of the Sapienza University of Rome. The model was scaled according to the Froude number and fully developed turbulent flow conditions were reproduced at the model scale (Re > 10,000). From the analysis of the results of both the physical and the numerical models, it is clear that the stilling basin is undersized and therefore insufficient to manage the energy content of the fluid output to the river, with a significant impact on the erodible downstream river bottom in terms of scour depths. Furthermore, the numerical model showed that a less vigorous jet-like flow is obtained by removing one of the sills the dam is supplied with

Surface doping in T6/ PDI-8CN2 Heterostructures investigated by transport and photoemission measurements

In this paper, we discuss the surface doping in sexithiophene (T6) organic field-effect transistors by PDI-8CN2. We show that an accumulation heterojunction is formed at the interface between the organic semiconductors and that the consequent band bending in T6 caused by PDI-8CN2 deposition can be addressed as the cause of the surface doping in T6 transistors. Several evidences of this phenomenon have been furnished both by electrical transport and photoemission measurements, namely the increase in the conductivity, the shift of the threshold voltage and the shift of the T6 HOMO peak towards higher binding energies.Comment: 5 pages, 5 figure

In silico analysis of TTR gene (coding and non-coding regions, and interactive network) and its implications in transthyretin-related amyloidosis.

Introduction: Transthyretin (TTR)-related amyloidosis is a life-threatening disease. Currently, several questions about the pathogenic mechanisms of TTR-related amyloidosis remain unanswered. Methods: We have investigated various TTR-related issues using different in silico approaches. Results: Using an amino acid similarity-based analysis, we have indicated the most relevant TTR secondary structures in determining mutation impact. Our amyloidogenic propensity analysis of TTR missense substitutions has highlighted a similar pattern for wild-type and mutated TTR amino b acid sequences. However, some mutations present differences with respect to the general distribution. We have identified non-coding variants in cis-regulatory elements of the TTR gene, and our analysis on V122I-related haplotypes has indicated differences in non-coding regulatory variants, suggesting differences among V122I carriers. The analysis of methylation status indicated CpG sites that may affect TTR expression. Finally, our interactive network analysis revealed functional partners of TTR that may play a modifier role in the pathogenesis of TTR-related amyloidosis. Discussion and conclusion: Our data provided new insights into the pathogenesis of TTR-related amyloidosis that, if they were to be confirmed through experimental investigations, could significantly improve our understanding of the disease

Improvement in workability of terminals placed along the inner side of port vertical breakwaters by means of recurved parapet walls

The function of main port breakwaters is to protect harbour basins from incoming waves and currents. In the event that a maritime terminal is placed on the inner side of a main breakwater, it is extremely important to limit waves overtopping the structure, because the overtopping flows may be very dangerous for the safety of the operations taking place in the terminal. Very often during storms if the overtopping discharges are severe, the terminal is temporarily closed, reducing its average annual workability accordingly. Wave overtopping is normally limited by using high parapet walls (crownwalls) which are not well considered from an environmental point of view due to their visual impact. A good solution to reduce wave overtopping limiting the increasing of the crownwalls height, is to use recurved parapet walls. The paper presents a new formula for recurved walls which can be used to estimate the overtopping flow rates reduction compared to normal vertical parapets. The formula has been obtained for vertical breakwaters by using numerical computations. The recurved parapet has the shape of a circumference sector, characterized by a radius and an opening angle. The numerical computations were performed applying OpenFOAM® which solves the 3D RANS equations for multiphase flows (air and water). The results show the high hydraulic efficiency of recurved walls in reducing overtopping rates compared to traditional vertical parapets

Lidar in Space Technology Experiment correlative measurements by lidar in Potenza, southern Italy.

An intensive lidar measurement campaign was carried out in Potenza (40°36′N-15°44′E, 820 m above sea level (asl)) in conjunction with the Lidar in Space Technology Experiment (LITE) mission and primarily aimed at the validation of LITE stratospheric aerosol measurements. Potenza lidar measurements in coincidence with all five nighttime overpasses near southern Italy (September 11, 12, 17, and 18, 1994) are compared with simultaneous LITE data. Potenza lidar data appear to be highly correlated with LITE data both at 355 and 532 nm. Potenza lidar versus LITE measurements of the aerosol-scattering ratio show a correlation coefficient of 0.72–0.81 at 355 nm and 0.88–0.93 at 532 nm, with an average calibration coefficient of 0.92 ± 0.19 at 355 nm and 1.02 ± 0.07 at 532 nm. Comparisons are also made in terms of the average Angstrom coefficient, whose values are consistent with submicrometer aerosol particles. Finally, Potenza lidar measurements of the aerosol layer base and top heights, the peak aerosol-scattering ratio and peak height, as well as of the aerosol scattering ratio at the cloud base appear to be consistent with measurements performed by other ground lidar stations in Europe during the LITE campaign as well as with the LITE data

Role of surface microgeometries on electron escape probability and secondary electron yield of metal surfaces

The influence of microgeometries on the Secondary Electron Yield (SEY) of surfaces is investigated. Laser written structures of different aspect ratio (height to width) on a copper surface tuned the SEY of the surface and reduced its value to less than unity. The aspect ratio of microstructures was methodically controlled by varying the laser parameters. The results obtained corroborate a recent theoretical model of SEY reduction as a function of the aspect ratio of microstructures. Nanostructures - which are formed inside the microstructures during the interaction with the laser beam - provided further reduction in SEY comparable to that obtained in the simulation of structures which were coated with an absorptive layer suppressing secondary electron emission