571 research outputs found

    Quantum mechanical ab-initio simulation of the electron screening effect in metal deuteride crystals

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    In antecedent experiments the electron screening energies of the d+d reactions in metallic environments have been determined to be enhanced by an order of magnitude in comparison to the case of gaseous deuterium targets. The analytical models describing averaged material properties have not been able to explain the experimental results so far. Therefore, a first effort has been undertaken to simulate the dynamics of reacting deuterons in a metallic lattice by means of an ab-initio Hartree-Fock calculation of the total electrostatic force between the lattice and the successively approaching deuterons via path integration. The calculations have been performed for Li and Ta, clearly showing a migration of electrons from host metallic to the deuterium atoms. However, in order to avoid more of the necessary simplifications in the model the utilization of a massive parallel supercomputer would be required.Comment: 11 pages, 12 figures, svjour class. To be published in Eur. Phys. J.

    Comparative analysis between subjective and instrumental quality assessment through advanced technology: a pilot study on tennis serve

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    The purpose of this study in the first instance is to evaluate objectively, with data provided by latest-generation inertial sensors, the dynamic qualities of the technical-sporting gestures such as serve in tennis. Furthermore, the possible correlation between the aforementioned data and the evaluation monitoring of the specialized technical staff (Italian Tennis Federation qualified Coach) was assessed, in essence, a comparison between objective instrumental data and quality technical analysis. The study is not based on probative statistical numbers, five athletes, but the interest of the research is focused on establishing the validity, reliability and reproducibility of the information deriving from the acquisition with inertial instrumentation in the sport of tennis. The work seemed useful also by virtue of the fact that in the literature not many works have been produced on the subject at the moment, and in any case not with the latest technologies as in our case (K-Track, K-Sport Universal, Stats Perform, Montecchio PU, Italy). As mentioned, the research took into consideration the technical fundamental of the serve, an element that has taken on more and more importance in modern tennis in the achievement of the point and therefore in the result of the game. The serve is the stroke that marks the beginning of each point and that can influence the continuance of the same. Moreover, due to the speed of the surfaces of the fields and the game, the serve became in effect a substantial percentage of the final victory of the match. This is the basic motivation that led us to analyse this fundamental and its biomechanical composition, however, highlighting those elements that best qualify the gesture in a performative sense, trying to establish parameters that can be considered helpful for the technical staff and for the tennis player,in order to improve their performance. Keywords: IMU, tennis serve, comparative analysis, technical evaluation, professional evaluation, physical dat

    The physical effort required from professional football players in different playing positions

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    The purpose of this study is to examine the physical effort required at professional football players (Italian Championship) in relation to the examination of a series of friendly matches at different times of the year, compared to their role, using the technology of GPS, for finalizing the training to improve the sport performance. The activities of players were monitored using GPS technology with a sampling rate of 10 Hz. The total distance covered, distances with different speed and accelerations were analyzed in relation to five different roles: (CD) central defenders, (FB) full-backs, (M) midfielders, (AM) advanced midfielders and (A) attackers. Players activities were monitored using GPS technology with a sampling rate of 10 Hz. Total distance covered, distance at different speeds and accelerations were analyzed in relation in five different roles: (CD) central defenders, (FB) full-backs, (M) midfielders, (AM) advanced midfielders and (A) attackers. The maximum covered distance (over 10 km) during a friendly match was reached by the third (FB), midfielders (M) and advanced midfielders (AM); The same ones have covered, too, the greatest distances in high-intensity running (> 16 km/h); instead, the attackers and central defenders covered the distance in high power. The full-backs (FB) and Advanced Midfielders (AM) have producted high acceleration and deceleration compared to other roles, while midfielders (M) have developed greater metabolic power. Finally, the end-of-season results were compared with the data gained at the beginning of the year and important differences between the various roles were noted

    ASSESSMENT OF FUTURE EMPLOYMENT AND COMPETENCY SKILLS IN BUILDING INFORMATION MODELING: A DELPHI STUDY

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    Many mainstream architecture, engineering, and construction (AEC) professionals are using Building Information Modeling (BIM). Although more and more firms are using BIM and this trend is forecast to continue, it is unclear what skills and competencies a construction manager will need in five years related to BIM. This research aims to answer that question through the use of a Delphi panel comprised of AEC professionals. The panel consists of members with the following qualifications: a minimum of eight years industry or academic experience or a combination of the two, a minimum of three years BIM experience, and membership in a nationally recognized professional organization. The results of the three round Delphi study identified skills and competencies in the following areas related to construction management: cost estimating (78 skills and competencies), scheduling and control (85 skills and competencies), project administration (71 skills and competencies), contract documents (29 skills and competencies), and other skills that were not in other categories (20 skills and competencies). In addition, this study reached consensus on descriptors that individual firms (24 descriptors) and construction mangers (22 descriptors) will need to possess to maintain or increase BIM usage in five-years. Although the panel identified many “new” BIM related construction management skills and competencies, “traditional” skills and competencies are a top response in each respective category. Within these “traditional” skills was the reinforcement of soft skills. BIM is a collaborative project management system so many soft skills are more important than with traditional project management systems. BIM requires some efficient communication along with strong soft skills, an area reinforced by the findings of this research. Furthermore, this research concluded that as BIM diffuses into the construction community, social systems interested in increasing BIM usage should augment “traditional” skill sets with the “new” BIM related skills and competencies. Any academic programs seeking to implement BIM related topics into existing courses should do so in a careful manner. This research revealed in five-years BIM will continue to enter the mainstream. Building Information Modeling theory suggests that AEC industry will completely change because of BIM. However, this is not the entirely the case. This research discovered that soft skills are more important because of BIM diffusion. This research will be of particular interest to industry and academic programs seeking to increase BIM usage, or begin development of curriculum that incorporates BIM. The results include a consensus of the most important skills and competencies related to BIM for a construction manager to possess, as ranked by mean and standard deviation

    STUDY ON PHYSICAL EDUCATION AND SPORT

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    MIUR enacted last year the new Guidelines of Physical Education and Sport to improve the sport activity into the school through the sport school association and gives, for this aim, only 33% of amount of economical resources that, in the past years, allocated for extra activity of physical education and sport. From a case study to compare data between 2 years of a sample of 10 schools of Naples, 6 schools decreased sports activity, 4 schools increased little bit and only 1 increased because had added own economical resource. Furthermore this one also deliberated a school sport association in collaboration to sport association as suggests new Guidelines. The aim of this study is to know which process the school adopted. Method is case study to describe the process and steps. All 10 schools confirm the past sport activities in different forms with several percentages among the schools are very good in consideration of the bad actual context of public school. But the significant decrease of number of students, which are generally distributed in every school, must do a reflection on general situation of high sport left. The 7 schools utilized only the economical ministerial resource and only 2 schools utilized economical ministerial resources is the demonstration of low culture in physical education and sport into school. Furthermore, the low additional own economical resources is relevant to demonstrate the gravity of situation. The datum of only 1 school added own economical resource in congruent amount means that just the 10% of schools understand the spirit of change according to the new Guidelines of Physical Education and Sport. The study suggests to start an investigation on public sport education service offered by school and by sport association and to establish a specific committee to research on this phenomenon to carry out the data to know every aspect of it

    Small oligonucleotides detection in three-dimensional polymer network of dna-peg hydrogels

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    The control of the three-dimensional (3D) polymer network structure is important for permselective materials when specific biomolecule detection is needed. Here we investigate conditions to obtain a tailored hydrogel network that combines both molecular filtering and molecular capture capabilities for biosensing applications. Along this line, short oligonucleotide detection in a displacement assay is set within PEGDA hydrogels synthetized by UV radical photopolymerization. To provide insights on the molecular filter capability, diffusion studies of several probes (sulforho-damine G and dextrans) with different hydrodynamic radii were carried out using NMR technique. Moreover, fluorometric analyses of hybridization of DNA oligonucleotides inside PEGDA hydrogels shed light on the mechanisms of recognition in 3D, highlighting that mesh size and crowding effect greatly impact the hybridization mechanism on a polymer network. Finally, we found the best probe density and diffusion transport conditions to allow the specific oligonucleotide capture and detection inside PEGDA hydrogels for oligonucleotide detection and the filtering out of higher molecular weight molecules

    Anomalous enhancements of low-energy fusion rates in plasmas: the role of ion momentum distributions and inhomogeneous screening

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    Non-resonant fusion cross-sections significantly higher than corresponding theoretical predictions are observed in low-energy experiments with deuterated matrix target. Models based on thermal effects, electron screening, or quantum-effect dispersion relations have been proposed to explain these anomalous results: none of them appears to satisfactory reproduce the experiments. Velocity distributions are fundamental for the reaction rates and deviations from the Maxwellian limit could play a central role in explaining the enhancement. We examine two effects: an increase of the tail of the target Deuteron momentum distribution due to the Galitskii-Yakimets quantum uncertainty effect, which broadens the energy-momentum relation; and spatial fluctuations of the Debye-H\"{u}ckel radius leading to an effective increase of electron screening. Either effect leads to larger reaction rates especially large at energies below a few keV, reducing the discrepancy between observations and theoretical expectations.Comment: 6 pages, 3 figure

    Physical Efficiency Index (PEI) and injuries after return to play post Covid-19 in Italian Serie A.

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    The aim of this study is analyze physical performance in Italian Serie A 2019-2020, after return to play post Covid-19, in the 20 club participants in the championship (n=567 players, age 27.2±1.1, value: 8.12 mln), to understand the causes of injuries that occurred during the last 12 match for the conclusion of the Serie A and variation in high intensity production. The analysis of physical performance is analyzed with SPORTVU OPTICAL TRACKING (STATS PERFORM, CHICAGO, USA) during each football match, from 27 match day (June 2020, after lockdown) to 38 match day (August 2020). Using a semiautomatic video analysis system that has incorporated new parameters able to measure physical efficiency (“Method for game analysis”, patented in 2010, PCT/IB2010/002593, K-SPORT UNIVERSAL, MONTELABBATE, ITALY). At the same time we analyzed players absence from each match day for all teams (n=20), to better understand how many injuries the lockdown (3 and a half months) caused over time. Our research relates with a professional Top Level Championship, physical efficiency index and injuries occured during a post Covid-19 period. The championship was suspended due to the Covid-19 emergency on matchday 26 and restart from matchday 27a in June 2020. The percentage of absences due to injury by comparing matchday 27 (post lockdown) and matchday 38 (last season) has showed a statistically significant increase 26% (n=20; p<0.05). Negative correlations was found between PEI (Physical Efficiency Index) and number of injuries occured post lockdown respectively, (n=20, r = -0.25, p > 0.05). For the 2019-20 season there is a total number of absences equal to 2213; compared with the data of the last thirteen seasons , an increase of 6%, statistical meaningfulness, (n=20; p<0.05) is observed compared to the previous season (2018-19). Key performance indicators in this research not predict injuries and they have a low correlation with them. Future studies it’s necessary to have more information on absence of injuires and their relation with performance and techinical/tactical game intelligence. Of course, PEI (Physical Efficiency Index), it’s a good indicator of physical team condition

    Screening enhancement factors for laboratory CNO and rp astrophysical reactions

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    Cross sections of laboratory CNO and rp astrophysical reactions are enhanced due to the presence of the multi-electron cloud that surrounds the target nuclei. As a result the relevant astrophysical factors are overestimated unless corrected appropriately. This study gives both an estimate of the error committed if screening effects are not taken into account and a rough profile of the laboratory energy thresholds at which the screening effect appears. The results indicate that, for most practical purposes, screening corrections to past relevant experiments can be disregarded. Regarding future experiments, however, screening corrections to the CNO reactions will certainly be of importance as they are closely related to the solar neutrino fluxes and the rp process. Moreover, according to the present results, screening effects will have to be taken into account particularly by the current and future LUNA experiments, where screened astrophysical factors will be enhanced to a significant degree.Comment: 6 RevTex pages + 2 ps figures. (Revised version). Accepted for publication in Journal of Physics

    Motor imagery, perspective taking and gender differences: A VVIQ2-based study

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    Scientific literature highlighted gender differences in spatial orientation. In particular, men and women differ in terms of the navigational processes they use in daily life. Scientific literature highlighted that women use analytical strategies while men tend to use holistic strategies. Furthermore, studies exploring gender differences in self-reported dream perspectives reported that women dream mainly in first person and men mainly in third person. This work used Vividness of Movement Imagery Questionnaire-2 to verify if gender differences in perspective taking last also in motor imagery practice. The aim of VVIQ2 questionnaire is to determine the vividness of movement imagery. In the VVIQ2, the image can be obtained watching oneself while performing the movement from an external point of view (External Visual Imagery), or from an internal point of view, as if you were looking out through your own eyes while performing the movement (Internal Visual Imagery). The Questionnaire was administered to students of Sports Sciences Degree from University of Salern
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