918 research outputs found
Earthquake Early Warning System for Structural Drift Prediction Using Machine Learning and Linear Regressors
In this work, we explored the feasibility of predicting the structural drift from the first seconds of P-wave signals for On-site Earthquake Early Warning (EEW) applications. To this purpose, we investigated the performance of both linear least square regression (LSR) and four non-linear machine learning (ML) models: Random Forest, Gradient Boosting, Support Vector Machines and K-Nearest Neighbors. Furthermore, we also explore the applicability of the models calibrated for a region to another one. The LSR and ML models are calibrated and validated using a dataset of âŒ6,000 waveforms recorded within 34 Japanese structures with three different type of construction (steel, reinforced concrete, and steel-reinforced concrete), and a smaller one of data recorded at US buildings (69 buildings, 240 waveforms). As EEW information, we considered three P-wave parameters (the peak displacement, Pd, the integral of squared velocity, IV2, and displacement, ID2) using three time-windows (i.e., 1, 2, and 3 s), for a total of nine features to predict the drift ratio as structural response. The Japanese dataset is used to calibrate the LSR and ML models and to study their capability to predict the structural drift. We explored different subsets of the Japanese dataset (i.e., one building, one single type of construction, the entire dataset. We found that the variability of both ground motion and buildings response can affect the drift predictions robustness. In particular, the predictions accuracy worsens with the complexity of the dataset in terms of building and event variability. Our results show that ML techniques perform always better than LSR models, likely due to the complex connections between features and the natural non-linearity of the data. Furthermore, we show that by implementing a residuals analysis, the main sources of drift variability can be identified. Finally, the models trained on the Japanese dataset are applied the US dataset. In our application, we found that the exporting EEW models worsen the prediction variability, but also that by including correction terms as function of the magnitude can strongly mitigate such problem. In other words, our results show that the drift for US buildings can be predicted by minor tweaks to models
Paleoecology of benthic foraminifera from the upper Burdigalian-lower Langhian la Vedova section (CĂČnero Riviera, Marche Region, Italy).
Manufacturing and Validation of a Novel Composite Component for Aircraft Main Landing Gear Bay
Composite materials may reduce the final weight of the aircraft structural components, in addition to
improve fatigue performance and corrosion resistance. In order to achieve the optimization of air transport
systems, making them increasingly sustainable, the structural design must be surely reviewed, starting to
follow the ââcomposite thinkingââ philosophy. The present research provides some relevant outcomes concerning
the design of a composite sample for the main landing gear bay of a large commercial airplane
(EASA CS25 category), within ITEMB (integrated full composite main landing gear bay concept) project, a
program of Clean Sky 2 EU research framework. The most ambitious goal is to develop a new generation of
lower center fuselage (LCF) with an innovative integrated landing system in the fuselage, which is considered
the next frontier in the development of landing systems for medium-haul aircraft, such as the
Airbus A320 aircraft family. The development of a different architecture, with the landing gear integrated
within the related fuselage bay, could lead to a simplification of the whole subassembly with potential
advantage in terms of construction and assembly times. Final target of the project is the manufacturing of
an innovative monolithic composite structure that will replace the actual configuration (a mixed structure of
metal and composite subassemblies) reducing or actually removing all the cost of assembly and increasing
the production rate. This paper presents the main results of the work, introducing the main processing steps
and prototype results; in the last part of the work, also some experimental tests on significant element are
introduced as the first assessment of the technology readiness level that has been achieved
Kinematics and Timing Constraints in a TranspressiveTectonic Regime: The Example of the Posada-AsinaraShear Zone (NE Sardinia, Italy)
The Impact of Precipitation and Sublimation Processes on Snow Accumulation: Preliminary Results
The need for climate change prediction has focused attention on the Surface Mass Balance (SMB) of the Antarctic continent and on how it influences the sea level. The SMB of the Antarctic plateau is governed by the equilibrium between precipitation and ablation processes such as sublimation and wind-borne snow redistribution. At scales of hundreds of kilometres snowfall variability dominates the snow accumulation process (Dery and Yau, 2002); at smaller scales, postdepositional process such as wind-borne redistribution, surface sublimation and
snowdrift sublimation becomes more important. In recent years the sublimation phenomenon has received much attention from the glacial-meteorological community, and some theoretical studies have tried to model it (Bintanja, 1998; Dery & Yau, 2001b; Frezzotti, 2004). There are two different types of sublimation: surface sublimation and blowing snow sublimation. Surface sublimation is mostly determined by the continual exchange of water between the air (in the vapour phase) and the snow pack (in the solid phase) due to solar irradiance. Blowing snow sublimation is possibly the more effective of the two sublimation processes. It occurs when snow particles at the surface are blown by winds exceeding a certain threshold value. Particles suspended in the sub saturated Atmospheric Boundary Layer (ABL) sublimate at a relatively fast rate, cooling air mass transported by the wind and increasing the local atmospheric moisture content. When the first few meters of the ABL are completely saturated, the process is dumped. It takes a
long time to meet this condition because katabatic winds transport saturated air
masses to the coast, thereby reactivating sublimation. The role of sublimation in snow accumulation and its high variability at local scales are not fully understood due to the few available measurements in Antarctica.
Further study and field experiments are required
Evaluation of corneal distortion characteristics in different eyes using Scheimpflug camera device
Objective. To study the correlations between corneal distortion and morphological features in different kinds of eyes such as healthy ones (HE), ones previously undergone myopic PRK (PRKE), ones affected by keratoconus (KCE) and keratoconus eyes previously undergone corneal collagen crosslinking (CCCE). Materials and Methods. In this retrospective comparative study, a total of 106 HE of 106 patients, 58 PRKE of 58 patients, 33 KCE of 33 patients, 28 CCCE of 28 patients were included. A complete examination of all eyes was followed by tomographic (Pentacam, Oculus, Wetzlar, Germany) and biomechanical (Corvis ST, Oculus, Wetzlar, Germany) evaluation. Differences among Corvis ST (CST) parameters in the different groups have been analyzed. Linear regressions between central corneal thickness (CCT), intraocular pressure (IOP) and anterior corneal curvature measured with Simulated Keratometry (SK), versus corneal deformation parameters measured with Corvis ST in the different groups, have been run using SPSS software version 18.0. Results, HE showed a significant correlation between main curvature power of the cornea within the central 3 mm expressed in Diopters (KM) and 6 CST parameters; between CCT and 4 CST parameters and between IOP and 5 CST parameters. PRKE showed a significant correlation between KM and 3 CST parameters; between IOP and 4 CST parameters and none between CCT and CST parameters. KCE showed a significant correlation between SK and 3 CST parameters; between IOP and 3 CST parameters and none between CCT and CST parameters. CCCE showed a significant correlation between KM and 5 CST parameters; between CCT and 1 CST parameters and between IOP and 5 CST parameters. Discussion. Data of this study suggest that both corneal curvature and IOP could have a greater influence on the corneal deformation, compared to central corneal thickness (CCT). These results should be taken into account by further studies aiming to assess biomechanical corneal characteristics
Delayed Effect of Dendritic Cells Vaccination on Survival in Glioblastoma: A Systematic Review and MetaâAnalysis
Background: Dendritic cell vaccination (DCV) strategies, thanks to a complex immune response, may flare tumor regression and improve patientsâ longâterm survival. This metaâanalysis aims to assess the efficacy of DCV for newly diagnosed glioblastoma patients in clinical trials. Meth-ods: The study databases, including PubMed, Web of Knowledge, Google Scholar, Scopus, and Cochrane, were searched by two blinded investigators considering eligible studies based on the following keywords: âglioblastoma multiformeâ, âdendritic cellâ, âvaccinationâ, âimmunother-apyâ, âimmune systemâ, âimmune responseâ, âchemotherapyâ, ârecurrenceâ, and âte-mozolomideâ. Among the 157 screened, only 15 articles were eligible for the final analysis. Results: Regimens including DCV showed no effect on 6âmonth progressionâfree survival (PFS, HR = 1.385, 95% CI: 0.822â2.335, p = 0.673) or on 6âmonth overall survival (OS, HR = 1.408, 95% CI: 0.882â2.248, p = 0.754). In contrast, DCV led to significantly longer 1âyear OS (HR = 1.936, 95% CI: 1.396â2.85, p = 0.001) and longer 2âyear OS (HR = 3.670, 95% CI: 2.291â5.879, p = 0.001) versus control groups. Hence, introducing DCV could lead to increased 1 and 2âyear survival of patients by 1.9 and 3.6 times, respectively. Conclusion: Antitumor regimens including DCV can effectively improve mid-term survival in patients suffering glioblastoma multiforme (GBM), but its impact emerges only after one year from vaccination. These data indicate the need for more time to achieve an antiâGBM immune response and suggest additional therapeutics, such as checkpoint inhibitors, to empower an earlier DCV action in patients affected by a very poor prognosis
[Myositis specific and myositis associated autoantibodies in idiopathic inflammatory myopathies: a serologic study of 46 patients]
Objective. To characterize serum autoantibody profiles of patients with idiopathic inflammatory myopathies (IIM) by searching for myositis-specific (MSA) and myositis-associated (MAA) antibodies with sensitive and specific laboratory tests. Methods. We tested the sera from 46 Caucasian patients diagnosed as affected with IIM at the Division of Rheumatology of Padova University (21 polimyositis, PM; 22 dermatomyositis, DM; 3 myositis overlap syndrome). All patients had definite IIM according to the criteria of Bohan-Peter. MSA including anti-tRNA synthetase (anti-Jo-1 and others) and anti-Mi-2 were determined by RNA immunoprecipitation and a modified immunoblot test, respectively. MAA (-U1RNP, -U2RNP, RoRNP, PM/Scl, Ku) were detected by counterimmunoelectrophoresis and immunoblot. Results. Serum MSA and/or MAA were found in 30/46 (65%) patients with IIM. Twenty-three patients (50%) were positive for at least one MSA: anti-Jo-1 in 15 (33%), anti-Mi-2 in 6 (13%), and other anti-tRNA synthetase in 3 (6%).One patient was anti-Jo-1/Mi-2 positive. Moreover, 18 patients (39%) were positive for at least one MAA: anti-Ro/SSA in 13 (28%), anti-U1RNP in 4 (9%), anti-PM/Scl in 1 (2%) and anti-Ku in 1 (2%). Coexisting MSA and MAA were observed in 8 patients (17%), anti-Jo-1/SSA positive in most cases. Anti-Jo-1 was predominantly associated with PM (57% in PM vs 14% in DM), whereas anti-Mi-2 was exclusively found in DM patients (27%). Anti-synthetase antibodies were closely associated with interstitial lung disease and polyarthritis; anti-Mi-2 positive DM patients did not have lung involvement. Notably, anti-Ro/SSA antibody was frequently observed and almost equally detected in either PM or DM (about 30%): in more than 50% of cases the antibody was associated with one MSA. Conclusions. By means of analytically reliable methods, MSA was detected in 50% of our IIM patients. Searching for MSA in patients with IIM is recommended because of its diagnostic and prognostic value
Emergency Department as an epidemiological observatory of Human Mobility: the experience of the Moroccan population
We conducted a retrospective study of the accesses to the Emergency Department registered from January 2000 to December 2014 in 5 major hospitals in the Metropolitan Area of Rome. We extrapolated data relating to patients of Moroccan origin from about 5 million total accesses, so we compared with Italians data which, in the same period, came to ED.
The Moroccan population is distinguished by a larger number of diagnoses belonging to the ICD-9 code of Infectious Diseases and, more precisely, to Respiratory Infectious Diseases. There are also no differences in the assignment of such diagnoses to Moroccans with Italian citizenship, and this led to think that this could play an important role in the use of the ED and moreover that enrollment to the National Health Service may reduce its inappropriate use.
Regarding to Degenerative Disorders, the result of our analysis is quite emblematic, showing that the accesses to the ED is due to Cardiovascular Diseases: 6.33% of Italians' accesses against 1.81% of Moroccans and 2.36% of Moroccans with Italian citizenship. The main explanation for this difference is, obviously, due to the age of the population: about 60% of Moroccans who accessed to ED was less than 40 years old.
It is interesting how, in the field of ââCardiovascular Diseases, Moroccans have a lower percentage of diagnosis compared to Italians for acute diseases and a greater percentage of diagnoses for chronic diseases, suggesting once again that accesses to ED for migrants often is due to the inability to use the general services of the National Health Service.
In conclusion, from the point of view of the Emergency Department, Migration Medicine still has Infectious Diseases as the main reason for access. Degenerative Disorders remain a prerogative of the Italians, but we could certainly assume that the Moroccan population would develop at some point with the aging
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