1,686 research outputs found
Capabilities of an Underwater Detector as a Neutrino Telescope and for the Neutrino Oscillation Search
No full textWe report on the results of a Monte Carlo simulation study of a km3 scale deep underwater Cherenkov detector aimed at detecting neutrinos of astrophysical origin. This analysis has been undertaken as part of the NEMO R&D project to develop such an experiment close to the Southern Italian coasts. We have studied the reconstruction capabilities of various arrays of phototubes in order to determine the detector geometries which optimize performance and cost. We have also investigated the possibility of designing a detector with characteristics suited to an experiment on atmospheric neutrino oscillations
Nutrition, activity behavior and body constitution in primary school children
No full textChild and adolescent obesity currently affects at least 10-25�0of the paediatric population in most developed countries. The BMI value is one of the most appropriate method of defining obesity and has a strong association with body fatness and health risk. Two main environmental factors, nutrition and physical activity, could influence paediatric obesity development. This paper studies the relationship between sedentariness, snack and soft drink intake and overweight or obesity in children. 1194 primary school children (age 8-10) participated in the study. For all the subjects we measured the anthropometric data to calculate the BMI. The overweight and obesity prevalence was estimated using age-specific BMI cutoffs. A questionaire was also submitted to all the children by a single interviewer to obtain data about: a) Weekly Physical Activity, b) Weekly Sedentary Activity, c) Alimentary Style. Spearman rank correlation and the Student’s t-test were used. The data demonstrated that 23.2�0of the children is overweight and the 4.8�0obese. BMI is inversely correlated to the physical activity, while there is positive correlation between BMI and number of double portions. Statistically significant positive correlation is present among eating snacks and hours of sedentariness, while there is a negative correlation between physical activity and TV hours. Physical activity in the childhood could be an important tool to prevent obesity development and adult-onset chronic diseases. It is important to encourage an active lifestyle in order to reduce sedentariness
Maxillary Transverse Deficit: A Retrospective Study of Two Biologically Oriented Devices through a Digital Workflow
No full textThe aim of this retrospective study was to compare the efficiency of two biologically oriented devices in achieving maxillary expansion: Rapid Palatal Expander (RPE) and Nitanium Palatal Expander-2 (NPE-2). Thirty-six subjects, divided in two equal groups, were included in this study. Maxillary dental arches were scanned using Trios 3 shape®, in order to perform a digital analysis of 3D models. The models were analyzed using Autodesk Fusion 360® and Meshmixer®. All data obtained from analysis of pre-treatment and post-treatment models were processed using Prism® software. The anterior arch width, the posterior arch width, the palate height, and palatal surface were measured to evaluate differences between the devices. A D’Agostino–Pearson normality test was done to check the data. A non-parametric t-test was used to compare the anterior and posterior arch width between the two groups, while a parametric t-test was used to compare the palatal height measurements between the two groups. The p-value was calculated. The limit value fixed was 0.05. Palatal width and surface showed a significant increase in both groups, but no significant changes in palatal height were found. The data processed showed that there were no significant differences between the devices (ΔREP−ΔNPE) in variation of anterior arch width, there were no significant differences in variation of posterior arch width and there were no significant differences in variation of palatal height. The comparison between the two groups showed that both methods were equally effective in correcting transverse defect
Methods for point source analysis in high energy neutrino telescopes
No full textNeutrino telescopes are moving steadily toward the goal of detecting astrophysical neutrinos from the most powerful galactic and extragalactic sources. Here we describe analysis methods to search for high energy point-like neutrino sources using detectors deep in the ice or sea. We simulate an ideal cubic kilometer detector based on real world performance of existing detectors such as AMANDA, IceCube, and ANTARES. An unbinned likelihood ratio method is applied, making use of the point spread function and energy distribution of simulated neutrino signal events to separate them from the background of atmospheric neutrinos produced by cosmic ray showers. The unbinned point source analyses are shown to perform better than binned searches and, depending on the source spectral index, the use of energy information is shown to improve discovery potential by almost a factor of two. (C) 2008 Elsevier B.V. All rights reserved
Changes in implant stability using different site preparation techniques: osseodensification drills versus piezoelectric surgery. A multi-center prospective randomized controlled clinical trial
No full textIntroduction: Implant stability is influenced by bone density, implant design, and site preparation characteristics. Piezoelectric implant site preparation (PISP) has been demonstrated to improve secondary stability compared with conventional drilling techniques. Osseodensification drills (OD) have been recently introduced to enhance both bone density and implant secondary stability. The objective of the present multi-center prospective randomized controlled trial was to monitor implant stability changes over the first 90 days of healing after implant bed preparation with OD or PISP.
Methods: Each patient received two identical, adjacent or contralateral implants in the posterior maxilla. Following randomization, test sites were prepared with OD and control sites with PISP. Resonance frequency analysis was performed immediately after implant placement and after 7, 14, 21, 28, 60, and 90 days. Implants were then restored with single screw-retained metal-ceramic crowns and followed for 12 months after loading.
Results: Twenty-seven patients (15 males and 12 females; mean age 63.0 ± 11.8 years) were included in final analysis. Each patient received two identical implants in the posterior maxilla (total = 54 implants). After 1 year of loading, 53 implants were satisfactorily in function (one failure in test group 28 days after placement). Mean peak insertion torque (40.7 ± 12.3 Ncm and 39.5 ± 10.2 Ncm in test and control group, respectively) and mean implant stability quotient (ISQ) value at baseline (71.3 ± 6.9 and 69.3 ± 7.6 in test and control group, respectively) showed no significant differences between the two groups. After an initial slight stability decrease, a shift to increasing ISQ values occurred after 14 days in control group and after 21 days in test group, but with no significant differences in ISQ values between the two groups during the first 90 days of healing.
Conclusion: No significant differences in either primary or secondary stability or implant survival rate after 1 year of loading were demonstrated between implants inserted into sites prepared with OD and PISP
Physical activity and dietary habits in 9-10-year-old children : a study in the province of Milan = Attività fisica e Stile alimentare in bambini di 9-10 anni : indagine nella provincia di Milano
No full textAim. The aim of this study was to evaluate the relationship between sedentary behavior, snacks and soft drink intake and overweight/obesity in 9-10-year-old children. Methods. The study population was 1 194 elementary school children residing in communities in the province of Milan. Body-mass index (BMI, kg/m2) was calculated and overweight and obesity rates were estimated using age-specific BMI cut-off values. A questionnaire administrated by the same interviewer investigated for weekly physical activity, weekly sedentary activity and dietary habits; specifically, the number of hours of weekly physical and sedentary activity and the number of extra helpings and soft drinks and snacks. Results. Spearman's rank correlation and Student's t-test were used to test correlations between the variables and BMI values. More physically active children had lower BMI values. Sedentary behavior at home correlated statistically with more hours watching TV, using the computer and playing videogames and with greater snack and soft drink intake. Increasing the amount of time spent in physical activity, because it increases energy expenditure and distracts children from consuming unnecessary food, couid be a useful way to prevent childhood obesity and adult-onset chronic diseases. Conclusion. Parents and teachers can play an instrumental role in encouraging a more active and healthy lifestyle in children by proposing extracurricular physical activity programs appropriate for this age group
Physical activity and dietary habits in 9-10 years old children : a study in the province of Milan
No full textObiettivo. Scopo di questa indagine è valutare le relazioni esistenti tra sedentarietà, consumo di merendine e bibite zuccherate e la presenza di sovrappeso e obesità nei bambini di 9-10 anni. Hanno partecipato allo studio 1194 bambini delle Scuole Elementari della provincia di Milano.
Metodi. I bambini sono stati sottoposti a misurazione di altezza e peso ed è stato valutato l’indice di massa corporea (body mass index, BMI): la presenza di sovrappeso e obesità è stata valutata considerando il punto di cut-off del BMI relativo all’età media del campione. Un unico esaminatore ha sottoposto ogni bambino alla compilazione guidata di un questionario, per ottenere informazioni riguardanti l’attività fisica settimanale, l’attività sedentaria settimanale e lo stile alimentare. Si sono così ottenuti dei valori numerici relativi al numero di ore di attività fisica e di attività sedentaria settimanale e alla quantità di porzioni extra e/o di bibite zuccherate e merendine, posti in relazione ai valori di BMI.
Risultati. Per la valutazione dei dati sono stati utilizzati il test t di Student e la correlazione dei ranghi secondo Spearman. I bambini più attivi fisicamente presentano valori di BMI più bassi. La sedentarietà durante il periodo di permanenza a casa è correlata statisticamente al fatto che i bambini guardano la TV e giocano con il computer o con i videogiochi, e questo comporta un maggior consumo di snack e bibite zuccherate. È risultato così evidente che una maggiore quan-tità di tempo dedicato all’attività fisica nei bambini ottiene il doppio scopo di aumentare il consumo calorico e di distoglierli dal consumo di alimenti non necessari, rappresentando così un valido mezzo per prevenire lo sviluppo di obesità e di malattie croniche in età adulta.
Conclusioni. Genitori e insegnanti dovrebbero motivare i bambini verso uno stile di vita più dinamico e salutare, riducendone i momenti di sedentarietà e proponendo programmi di attività motoria extracurricolare adeguati all’età
Cosmic-ray discrimination capabilities of DE/dx silicon nuclear telescopes using neural networks
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