1,128 research outputs found

    Native-Migrant Differences in Trading Off Wages and Workplace Safety

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    Applying propensity score reweighting to Italian administrative data covering the period 1994-2012, we study the conditional distributions of injuries by wage of native and foreign workers and distinguish between the component that is explained by observable characteristics and the component that is instead attributable to the immigrant status. Our analyses highlight some stylized facts. Besides a substantial gap in wage and injury risk that cannot be attributed to differences in the characteristics, foreign workers face higher levels of risk by the same level of wages. The gap is significantly above the level predicted by their observable characteristics by remunerations that are close to the minimum wage level set by collective bargaining. After this threshold, injury rates decline, but less steeply for foreign workers than their observable characteristics would predict. We show that the hedonic wage model could explain the first result as a corner solution whereby workers with low wage potential are forced to accept higher levels of risk due to the lower bounds on minimum wage. The second results could simply be explained by assuming different utility functions for natives and foreigners. We also show that the hedonic wage model is compatible with the marked reduction in injury rates and in the gap that we observe in the recession years

    UN PERCORSO DI LEGITTIMAZIONE: DAL CIRUJEO ALL'ORGANIZZAZIONE COOPERATIVA

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    Si analizza l'attuale struttura economico-politica argentina in relazione alla storia del Paese, della quale si evidenziano i momenti più drammatici: dalle gravi problematiche economiche agli alti livelli di disoccupazione, dalle politiche pubbliche inefficienti agli effetti della crisi finanziaria, dagli anni del regime militare ai problemi sociali e ambientali dei giorni nostri. Viene inoltre studiata la nascita di un nuova fascia di attori sociali che ha trovato nella raccolta dei rifiuti riciclabili una vera e propria strategia di sopravvivenza: questa attività, svolta in un primo momento in modo informale, è stata in seguito regolarizzata e oggi, grazie alla diffusione del cooperativismo, sta gradualmente evolvendosi

    Impact assessment of an intelligent central tire inflation system for passenger cars

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    Tire inflation pressure affects vehicle energetic balance, as well as road safety. These issues are particularly critical due to the low attention paid by the drivers to tire maintenance. Tire pressure monitoring systems are used to alert the drivers in case of low pressure, but higher benefits could be obtained through a completely autonomous on-board system capable of setting the optimal tire pressure according to current working conditions and of automatically inflate or deflate tires. Basing on computer simulations on fuel economy of a reference mid-size diesel passenger car, and referring to statistical data on vehicle use, the potentialities of such a device is evaluated on an annual mission. The results are then extended to the whole European fleet to provide an estimation of the potential benefits that could be obtained through massive adoption of this solution. The impact is evaluated through an economical evaluation of: fuel savings, reduction of social cost of carbon emissions, increase of tire life and reduction of costs related to crashes produced by improper tire pressure

    Model-Based Calibration and Control of Tailpipe Nitrogen Oxide Emissions in a Light-Duty Diesel Engine and Its Assessment through Model-In-The-Loop

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    The present paper investigates two different strategies for model-based calibration and control of tailpipe nitrogen oxide emissions in a light-duty 3.0 L diesel engine equipped with an aftertreatment system (ATS). The latter includes a diesel oxidation catalyst (DOC), a diesel particulate filter (DPF), and an underfloor selective catalytic reduction (SCR) device, in which the injection of diesel exhaust fluid (DEF), marketed as ‘AdBlue’, is also taken into account. The engine was modeled in the GT-SUITE environment, and a previously developed model-based combustion controller was integrated in the model, which is capable of adjusting the start of injection of the main pulse and the total injected fuel mass, in order to achieve desired targets of engine-out nitrogen oxide emissions (NOx) and brake mean effective pressure (BMEP). First, a model-based calibration strategy consisting of the minimization of an objective function that takes into account fuel consumption and AdBlue injection was developed and assessed by exploring different weight factors. Then, a direct model-based controller of tailpipe nitrogen oxide emissions was designed, which exploits the real-time value of the SCR efficiency to define engine-out NOx emission targets for the combustion controller. Both strategies exploit the model-based combustion controller and were tested through a Model-in-the-Loop (MiL) under steady-state and transient conditions. The advantages in terms of tailpipe NOx emissions, fuel consumption, and AdBlue injection were finally discussed

    Results of medium seventeen years' follow-up after laparoscopic choledochotomy for ductal stones

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    INTRODUCTION: In a previously published article the authors reported the long-term follow-up results in 138 consecutive patients with gallstones and common bile duct (CBD) stones who underwent laparoscopic transverse choledochotomy (TC) with T-tube biliary drainage and laparoscopic cholecystectomy (LC). Aim of this study is to evaluate the results at up to 23 years of follow-up in the same series. METHODS: One hundred twenty-one patients are the object of the present study. Patients were evaluated by clinical visit, blood assay, and abdominal ultrasound. Symptomatic patients underwent cholangio-MRI, followed by endoscopic retrograde cholangiopancreatography (ERCP) as required. RESULTS: Out of 121 patients, 61 elderly patients died from unrelated causes. Fourteen patients were lost to follow-up. In the 46 remaining patients, ductal stone recurrence occurred in one case (2,1%) successfully managed by ERCP with endoscopic sphincterotomy. At a mean follow-up of 17.1 years no other patients showed signs of bile stasis and no patient showed any imaging evidence of CBD stricture at the site of choledochotomy. CONCLUSIONS: Laparoscopic transverse choledochotomy with routine T-tube biliary drainage during LC has proven to be safe and effective at up to 23 years of follow-up, with no evidence of CBD stricture when the procedure is performed with a correct technique

    Physics-Informed Extreme Theory of Functional Connections Applied to Data-Driven Parameters Discovery of Epidemiological Compartmental Models

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    In this work we apply a novel, accurate, fast, and robust physics-informed neural network framework for data-driven parameters discovery of problems modeled via parametric ordinary differential equations (ODEs) called the Extreme Theory of Functional Connections (X-TFC). The proposed method merges two recently developed frameworks for solving problems involving parametric DEs, 1) the Theory of Functional Connections (TFC) and 2) the Physics-Informed Neural Networks (PINN). In particular, this work focuses on the capability of X-TFC in solving inverse problems to estimate the parameters governing the epidemiological compartmental models via a deterministic approach. The epidemiological compartmental models treated in this work are Susceptible-Infectious-Recovered (SIR), Susceptible-Exposed-Infectious-Recovered (SEIR), and Susceptible-Exposed-Infectious-Recovered-Susceptible (SEIR). The results show the low computational times, the high accuracy and effectiveness of the X-TFC method in performing data-driven parameters discovery of systems modeled via parametric ODEs using unperturbed and perturbed data

    Is contrast-enhanced US alternative to spiral CT in the assessment of treatment outcome of radiofrequency ablation in hepatocellular carcinoma?

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    Purpose: The present study was conducted to assess the efficacy of contrast-enhanced ultrasound with low mechanical index in evaluating the response of percutaneous radiofrequency ablation treatment of hepatocellular carcinoma by comparing it with 4-row spiral computed tomography. Materials and Methods: 100 consecutive patients (65 men and 35 women; age range: 62 – 76 years) with solitary hepatocellular carcinomas (mean lesion diameter: 3.7cm± 1.1cm SD) underwent internally cooled radiofrequency ablation. Therapeutic response was evaluated at one month after the treatment with triple-phasic contrast-enhanced spiral CT and low-mechanical index contrast-enhanced ultrasound following bolus injection of 2.4 ml of Sonovue (Bracco, Milan). 60 out of 100 patients were followed up for another 3 months. Contrast-enhanced sonographic studies were reviewed by two blinded radiologists in consensus. Sensitivity, specificity, NPV and PPV of contrast-enhanced ultrasound examination were determined. Results: After treatment, contrast-enhanced ultrasound identified persistent signal enhancement in 24 patients (24%), whereas no intratumoral enhancement was detected in the remaining 76 patients (76%). Using CT imaging as gold standard, the sensitivity, specificity, NPV, and PPV of contrast enhanced ultrasound were 92.3% (95% CI = 75.9 – 97.9%), 100% (95% CI = 95.2 – 100%), 97.4% (95% CI = 91.1 – 99.3%), and 100% (95% CI = 86.2 – 100%). Conclusion: Contrast-enhanced ultrasound with low mechanical index using Sonovue is a feasible tool in evaluating the response of hepatocellular carcinoma to radiofrequency ablation. Accuracy is comparable to 4-row spiral CT
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