657 research outputs found
Road Safety Review: critical aspects of powered two wheelers
No full textPowered two wheelers (PTW) differ in their use of the road in a number of ways from other vehicles and they have different needs. Predictable road geometry, good visibility, obstacle free zones and good quality road surface with high levels of skid resistance are some major examples. While important for all road users, they are essential for PTW.
So the design of safe infrastructures for all travellers categories, included the motorcyclists, becomes a primary requirement. To obtain these results, Road Safety Audits and Road Safety Reviews are very useful tools. In this way, in fact, it is possible to examine a project or existing road, reporting its crash potential and safety performances and detecting its deficiencies without waiting for accidents accumulation.
In this paper the author, starting from data collected in numerous Road Safety Reviews on urban streets, provide significant results regarding roads project and maintenance in according to safety needs of all users, included the PTW drivers
Impact of vitamin D deficiency on the clinical and biochemical phenotype in women with sporadic primary hyperparathyroidism
No full textThe purpose of the study was to evaluate the relationship between serum 25(OH)D and the clinical phenotype in 215 consecutive Italian Caucasian women with sporadic primary hyperparathyroidism (PHPT) not taking vitamin D supplements. The study was performed at a single Italian tertiary center. PHPT-related manifestations, serum 25(OH)D, and other parameters of calcium metabolism and bone mineral density (BMD) by DXA were recorded. Serum 25(OH)D was negatively correlated with age (r = −0.18; P = 0.006), BMI (r = −0.20; P = 0.002), PTH (r = −0.21; P = 0.001), bone-specific alkaline phosphatase (BSAP) (r = −0.27; P < 0.001), and eGFR (r = −0.22; P = 0.01), and positively with serum creatinine and 1/3 distal radius BMD (R-BMD; r = 0.17; P = 0.015). In a multivariate regression analysis, serum 25(OH)D remained significantly correlated with age (r = −0.18; P = 0.005), BMI (r = −0.23; P = 0.049), serum PTH (r = −0.01; P = 0.023), BSAP (r = −0.01; P = 0.023) and eGFR (r = −0.09; P = 0.001), but not with R-BMD. Serum 25(OHD) was higher in patients with nephrolithiasis than in those without nephrolithiasis (18.5 ± 8.8 vs. 15.6 ± 8.0 ng/ml; P = 0.029), whereas no difference was found between fractured and unfractured patients (16.8 ± 9.3 vs. 16.0 ± 7.7; P = 0.663). There was a statistically significant inverse correlation between vitamin D status [defined by quartiles of measured values as well as commonly accepted cutoffs of serum 25(OH)D] and severity of the disease, as reflected by higher PTH and BSAP, but not by meeting the latest guidelines for parathyroidectomy. In conclusion, a low vitamin D status is associated with some features reflecting a more severe biochemical and clinical phenotype of PHPT in Italian women not taking vitamin D supplements
My perpetual cycle: from student to researcher to teacher to student ...
No full textThis contribution stems from the personal experience of the author regarding how he became acquainted with embryology and how he finally entered the field of developmental biology. It reports his feelings as a student of the Histology and Embryology course as it was taught in the late 1970s, and his present efforts in teaching developmental biology to university students. In the Developmental Biology course at Pisa University today, students are taught the tissue, molecular and genetic mechanisms that regulate development of several model systems. Drosophila is introduced at the beginning, because of the great knowledge that it has brought to the unraveling of the molecular aspects of development and because it allows several basic concepts to be introduced, and vertebrate systems follow. Other topics include the classic experiments on amphibian systems, which are explained in the light of recent molecular advances, as well as the genetically more versatile vertebrate systems such as the mouse
Il cimitero monumentale della Villetta di Parma. Guida per la manutenzione dei beni sepolcrali
No full textIl cimitero monumentale della Villetta di Parma. Guida per la manutenzione dei beni sepolcrali
No full textI materiali della memoria. Degrado e conservazione dei beni sepolcrali del cimitero monumentale della Villetta di Parma
No full textI MATERIALI DELLA MEMORIADegrado e conservazione dei beni sepolcrali del cimitero monumentale della Villetta di Parma
No full textI sepolcri e gli archi del Cimitero Monumentale La Villetta di Parma: guida pratica di manutenzione e restauro
No full textMicromechanical modelling of aggregate–aggregate interactions with distinct particle element method for virtual laboratory simulation
No full textRoad pavement performances are still not fully understood because it has been
necessary to simplify its materials behavior, modeling them as continuous. In reality, however, they
exhibit discontinuous performances, which do not always fit for the advanced continuum models
based on non-linear behavior very well.
To overcome this limitation, the Distinct Particle Elements Method (DEM), which schematizes a
granular material by particles that displace independently from one another and interact only at
contact points, becomes a good answer. In this way, in fact, is possible to analyze the discrete
character of mixes through a microscopic approach.
The author in a previous study have confirmed the DEM potentialities in the investigation of the
fatigue performances of asphalt mixes and have observed the great influence of particles geometry
on the materials response. So, in this paper, in order to deepen the effects of aggregate shape and
dimensions on the fatigue behavior of a road pavement, several triaxial laboratory compression tests
on specimens of steel particles have been simulated and the numerical results have been compared
with the lab ones
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