10,640 research outputs found
Valutazione delle lesioni nell\u2019impatto ciclista adolescente -veicolo con simulazione multibody
Le situazioni di impatto e la dinamica di ciclista e pedone sono le informazioni fondamentali per lo sviluppo di soluzioni efficaci per migliorare la protezione del pedone e del ciclista in caso di urto con autovetture. La casistica degli incidenti a Palermo, negli ultimi anni, avvenuti su strade urbane (84%) che coinvolgono adolescenti (6,4%), mostra che i ciclisti hanno in genere una posizione di impatto superiore rispetto al pedone, con una quota maggiore di lesioni per urti nella zona del parabrezza. In questo lavoro \ue8 eseguita la simulazione dinamica per lo studio delle lesioni alla testa e al torace dell\u2019adolescente, tra una bicicletta generica e un modello di auto che presenta caratteristiche vantaggiose per la sicurezza del pedone o del ciclista. Il software SimWise (Visual Nastran) \ue8 stato usato per la simulazione multibody dell\u2019impatto; il modello antropomorfo, l'auto e le biciclette sono quelli utilizzati in lavori precedenti. L'attenzione \ue8 su un ciclista adolescente, perch\ue9 i relativi dati di lesione si trovano in letteratura con difficolt\ue0. I dodici test d\u2019impatto completo (auto contro ciclista) hanno come parametri principali: velocit\ue0 del veicolo (20, 30, 40 e 50 km/h), con tre diverse posizioni del ciclista rispetto al veicolo: frontale, laterale e posteriore. La posizione di impatto della testa (sopra il cofano, nel parabrezza), determinato dalla prova di crash, mostra che la protezione del ciclista dovrebbe essere migliorata nella zona pi\uf9 alta del parabrezza, rispetto a quelle pedonali. La ferita alla testa viene analizzata utilizzando il parametro HIC e la ferita al torace \ue8 analizzata secondo il criterio dei 3 ms; viene calcolata la probabilit\ue0 AIS 4 +, concludendo che la lesione alla testa \ue8 pi\uf9 pericolosa in caso di pedone adolescente, mentre la ferita della cassa toracica \ue8 pi\uf9 pericolosa nel caso di ciclista adolescente. Inoltre il ciclista adolescente ha una maggiore possibilit\ue0 di sopravvivenza rispetto al ciclista adulto. Incidentologia e simulazioni mostrano che il parabrezza \ue8 una posizione di impatto frequente per testa e torace
Development of a tool to optimize the performance of a Maui Cluster Scheduler
The use of Linux cluster computing in a scientific and heterogeneous environment has been growing very fast in the past years. The often conflicting user’s requests of shared resources are quite difficult to satisfy for the administrators, and, usually, lower the overall system efficiency. In this scenario a new tool to study and
optimize the Maui Cluster Scheduler has been developed together with a new set of metrics to evaluate any given configuration. The main idea is to use the Maui internal simulator, fed by workloads produced either by a real cluster than by an ad hoc one, to test several scheduler configurations and then, using a genetic algorithm, to choose the best solution. In this work the architecture of the proposed tool is described together with the first results
obesity weight loss and heart failure
Background The current scientific data controversially indicate obesity both as a risk factor for developing congestive heart failure (CHF) and a positive prognostic factor. Aims The present study evaluated the impact of weight loss on clinical and instrumental parameters in a selected group of obese patients with CHF. Methods An overall population of 560 HF patients was sub-grouped on the basis of the Body Mass Index (BMI): 8.2% were underweight (BMI 31). Of the 46 overweight and obese patients, 28 (55.2% men, age 51–80 years) accepted a tailored low-caloric dietary program for at least 4 months. The 28 patients belonged to both obese and overweight groups (BMI>27.8) and were in NYHA classes II–III. Mean follow-up was 5 months. Results The mean loss of body weight was 4 kg in 81.4% of patients, versus 3 kg mean increase in whole (560 patients) population (72.5–75.5 kg). In the 28 patients we recorded a significant ( p <0.05) improvement of NYHA class, better control of arterial blood pressure and statistically significant ( p <0.05) lowering of total cholesterol and triglyceride levels. Conclusions Tailored dietetic program may improve clinical and instrumental parameters in patients with CHF
Forest road planning, construction and maintenance to improve forest fire fighting: A review
Forest roads play a key-role in fire fighting activities. In fact, all ground-based activities are strictly related to the presence of forest roads as access to fire edge. In spite of this important role, forest roads are often planned and built without considering their use in fire fighting, and this also occurs in literature, where few studies are dedicated to the importance of forest roads in fire fighting. A well-developed and well-maintained forest road network is the answer to different needs in fire management. The objective of this review is to clarify basic principles for obtaining efficient road network also for fire fighting, collecting, defining and resuming the main roles, the most important aspects and the reported experiences to be taken into account in forest road network planning and maintenance in fire-prone areas. The most important themes treated are related to: i) the analysis of the functions of forest roads in fire prevention and suppression; ii) the importance of forest road planning and building also considering their importance for protecting forests against fires: iii) the construction and maintenance characteristics to be considered for building and maintaining an efficient forest road network against fires; iv) the importance of fire prevention and the related role of forest roads. Special attention has been dedicated to maintenance activities, because a not well-maintained forest road is a not efficient forest road, and it represents a useless economic and environmental cost
Stroboscopic Laser Diagnostics for Detection of Ordering in One-Dimensional Ion beam
A novel diagnostic method for detecting ordering in one-dimensional ion beams
is presented. The ions are excited by a pulsed laser at two different positions
along the beam and fluorescence is observed by a group of four
photomultipliers. Correlation in fluorescence signals is firm indication that
the ion beam has an ordered structure.Comment: 7 pages, REVTEX, fig3 uuencoded, figs 1-2 available upon request from
[email protected], to appear in Phys. Rev.
Biological effects of a software-controlled voltage pulse generator (PhyBack PBK-2C) on the release of vascular endothelial growth factor (VEGF)
Electrical stimulation (ES) may induce vascular permeability and physiological angiogenesis. ES of rat muscles significantly increases the microvessel density and vascular endothelial growth factor (VEGF) protein levels. Thus, a pilot study was designed to analyze the effects of low-voltage electric impulses on VEGF levels in patients with dystrophic ulcers
- …