1,046 research outputs found
A genetic algorithm for the design of a fuzzy controller for active queue management
Active queue management (AQM) policies are those
policies of router queue management that allow for the detection of network congestion, the notification of such occurrences to the
hosts on the network borders, and the adoption of a suitable control
policy. This paper proposes the adoption of a fuzzy proportional
integral (FPI) controller as an active queue manager for Internet
routers. The analytical design of the proposed FPI controller is
carried out in analogy with a proportional integral (PI) controller,
which recently has been proposed for AQM. A genetic algorithm is
proposed for tuning of the FPI controller parameters with respect
to optimal disturbance rejection. In the paper the FPI controller
design metodology is described and the results of the comparison
with random early detection (RED), tail drop, and PI controller
are presented
Common fixed points of generalized Mizoguchi-Takahashi type contractions in partial metric spaces
We give some common fixed point results for multivalued mappings in the setting of complete
partial metric spaces. Our theorems extend and complement analogous results in the existing literature
on metric and partial metric spaces. Finally, we provide an example to illustrate the new theory
genetic diversity and relationship among the three autochthonous sicilian donkey populations assessed by microsatellite markers
AbstractIn the developed countries donkey has lost its main function as draft animal because of the mechanization in agri-culture; as a consequence donkey population was greatly reduced. According to SAVE monitoring institute, three of the eight Italian endangered donkey breeds are native of Sicily (Ragusano, Pantesco, Grigio Siciliano). Urgent safeguard plans are required. The aim of this work is to investigate the distribution of genetic diversity and the relationships among the three Sicilian autochthonous donkey breeds using a set of microsatellite markers. A total of 116 blood samples (61 Ragusano, 39 Pantesco, 16 Grigio Siciliano) were collected in 9 herds all over Sicily. Representative samples of Ragusano and Grigio donkey populations consist of unrelated individuals, whereas the sample of Pantesco represents nearly the entire studbook-registered population managed by "Ispettorato Ripartimentale delle Foreste di Erice (TP)" in the "Azienda S. Matteo". Genomic DNA was amplified at 11 microsatellite..
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Psychometric analysis and validation of the Italian Bergen Facebook Addiction Scale
Social media use, and specifically Facebook use, has become increasingly popular over the past decade. Despite the many benefits of social networking, a small minority of individuals appear to develop issues surrounding social media use, and more specifically Facebook use. It has, therefore, led some scholars to describe such problematic activity as a behavioral addiction. Such problematic behaviors have been reported in many countries including Italy. The present study validated and examined the reliability and validity of the Italian version of the Bergen Facebook Addiction Scale (BFAS) by conducting a psychometric examination among an Italian sample of adults (n = 217; aged 18 to 68 years). Internal reliability was examined using various indicators, including Cronbach’s α, which was excellent (α = 0.94). Results indicated that Facebook addiction was significantly correlated with social media addiction, smartphone addiction, narcissism, depression, and self-esteem. The results of the present study support the use of the Italian version of the BFAS in research and confirms the uni-dimensional nature of the single factor proposed by the original authors
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Validation and psychometric evaluation of the Italian version of the Fear of COVID-19 Scale
Background: The advent of COVID-19 worldwide has led to consequences for people’s health, both physical and psychological, such as fear and anxiety. This is the case in Italy, one of the countries most affected by the pandemic. Given the heightened fear concerning COVID-19 in Italy., the present study analyzed the psychometric properties of the Italian version of the Fear of COVID-19 Scale (FCV-19S).
Methods: The sample comprised 250 Italian participants who were administered Italian versions of the FCV-19S, the Hospital Anxiety and Depression Scale (HADS), and the Severity Measure for Specific Phobia–Adult (SMSP-A). Several psychometric tests were performed to investigate the validity and reliability of the test including confirmatory factor analysis.
Results: Analysis of the data showed satisfactory psychometric characteristics and confirmed the scale’s unidimensional properties. The seven FCV-19S items had acceptable correlations with the test total (from .443 to .784). Furthermore, the loadings on the factor were significant and strong (from .684 to .897). The internal consistency was very good (α = .871). Construct validity for the FCV-19S was supported by significant and positive correlations with the HADS (r=.649) and SMSP-A (r=.703).
Conclusions: The Italian version of the Fear of COVID-19 Scale is valid and reliable in assessing fear of COVID-19 among the general Italian population
Autonomic nervous system responses to strength training in top-level weight lifters
In athletes, spectral analysis of HR variability (HRV) has been shown capable to detect the adaptational changes in sympatho-vagal control attending physical training. So far, studies investigated autonomic nervous system (ANS) changes occurring with endurance training, whereas adaptations to markedly different exercise modes, for example, strength training, have never been investigated. We assessed the changes in cardiac ANS parameters during long-term training in weight lifters of the Italian team preparing for the European Championship, where athletes competed for obtaining the pass for Olympic Games. We investigated nine athletes. Subject trained 3 sessions/day, 6 days a week. The intensity of strength exercises varied from 70% to 95% 1 RM. Training load (TL) was calculated as: volume (min)
7 intensity (%1RM).All ANS parameters were significantly and highly correlated on an individual basis to the dose of exercise with a second-order regression model (r2 ranged from 0.96 to 0.99; P < 0.001). The low-frequency (LF) component of HRV and LF/HF ratio showed an initial increase with the progression of TL and then a decrease, resembling a bell-shaped curve with a minimum at the highest TL. The high-frequency (HF) component of HRV and R-R interval showed a reciprocal pattern, with an initial decrease with progression of TL followed by an increase, resembling an U-shaped curve with a maximum at the highest TL. These adaptations were at the opposite to those previously reported in endurance athletes. These results suggest that in Olympic weight lifters, ANS adaptations to training are dose-related on individual basis and that ANS adaptations are mainly sport-specific
One-hundred aortic valve replacements in octogenarians: Outcomes and risk factors for early mortality
Background and aim of the study: Today, ageing of the western population is causing aortic valve surgery to be performed in elderly patients with increasing frequency. The study aim was to evaluate surgical outcome in octogenarian patients undergoing aortic valve replacement (AVR). Methods: A total of 100 patients (mean age 82.1 +/- 2.7 years; range: 80-95 years) who underwent AVR over a three-year period was reviewed. Concomitant coronary artery bypass grafting was performed in 34% of cases, and a bioprosthesis was implanted in 80%. The mean logistic EuroSCORE was 13.3%. Results: Operative mortality was 8.0%. In multivariate analysis, a logistic EuroSCORE >= 13.5% (p = 0.02), cross-clamp time >= 75 min (p = 0.02) and postoperative acute renal failure were predictors for in-hospital mortality. Follow up was 100% complete; the mean follow up period was 10.6 months. At one year after surgery, the actuarial survival rate of those patients who survived surgery was 86.1%. Postoperative dyspnea at one month (p = 0.004) was the only predictor of short-term mortality. Conclusion: Age in itself should not contraindicate surgery, and healthcare systems should be prepared to accommodate elderly patients who may require special resources
Mitochondrial DNA control region variation in Sanfratellano horse and two other Sicilian autochthonous breeds
Mitochondrial D-loop hypervariable region was analysed in 20 Sanfratellano and two other Sicilian autochthonous horse breeds (20 Sicilian Oriental Purebred and 20 Sicilian Indigenous) in order to investigate matrilineal genetic diversity. A total of 20 different haplotypes were identified sequencing a fragment of 397 bp; overall, haplotypes showed 31 polymorphic sites (7.8%). High diversity was detected in Sanfratellano (11 haplotypes) and Sicilian Indigenous (13 haplotypes), whereas only one haplotype was found in Sicilian Oriental Purebred. Sanfratellano sequences were compared with those belonging to the other Sicilian autochthonous horses and 118 sequences selected from the GenBank database in order to calculate the statistics of molecular diversity. Six haplotypes were exclusive of Sanfratellano which shares haplotype C, D, H, and O with the Sicilian Indigenous and haplotype U with the Sicilian Oriental Purebred; not significant differentiation was found between Sanfratellano and Sicilian Indigenous. BLAST search showed Sicilian haplotypes overlap with the database sequences but for three. Phylogenetic analysis did not show monophyletic group for Sanfratellano samples or the other breeds included in this analysis
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