53,986 research outputs found
P2GP - Proportionality-based 2-phase Gradient Projection method
No full textP2GP is a MATLAB code for the solution of Quadratic Programming problems with a Single Linear constraint and Bounds on the variables (SLBQPs). The problems are not required to be strictly convex. The code implements the Proportionality-based 2-phase Gradient Projection method proposed in
D. di Serafino, G. Toraldo, M. Viola, J. Barlow, A two-phase gradient method for quadratic programming problems with a single linear constraint and bounds on the variables, SIAM Journal on Optimization, 28 (4), pp. 2809-2838, ISSN: 1052-6234, doi: 10.1137/17M1128538.
It also includes SLBQPgen, a generator of SLBQPs (and BQPs), described in Section 5.1 of the aforementioned article
Metamaterial-based Toraldo pupils for super-resolution at millimetre wavelengths
No full textUsing the long-established Cardiff metal-mesh filter technology, we have exploited our ability to artificially manipulate the phase of a wavefront across a device in order to produce a dielectric-based Toraldo pupil working at millimeter wavelengths. The use of a Toraldo pupil to push the angular resolution of an optical imaging system beyond the classical diffraction limit is yet to be realized in the millimeter regime, but is an exciting prospect. Here we present the design and measured performance of a prototype Toraldo pupil, based on a 5 annuli design
Using gradient directions to get global convergence of Newton-type methods
No full textThe renewed interest in Steepest Descent (SD) methods following the work of Barzilai and Borwein [2] has driven us to consider a globalization strategy based on SD, which is applicable to any line-search method. In particular, we combine Newton-type directions with scaled SD steps to have suitable descent directions. Scaling the SD directions with a suitable step length makes a significant difference with respect to similar globalization approaches, in terms of both theoretical features and computational behavior. We apply our strategy to Newton's method and the BFGS method, with computational results that appear interesting compared with the results of well-established globalization strategies devised ad hoc for those methods
A Novel Methodology for Planning Urban Road Safety Interventions
No full textImproving road safety is a major challenge for urban administrations due to the high frequency of accidents and their associated social costs. This study presents a methodology that combines historical accident data analysis with a proactive risk assessment approach to enhance decision-making in road safety planning. Using the International Road Assessment Programme (iRAP) and Geographic Information Systems (GIS), the proposed framework identifies high-risk locations and estimates the benefits of planned safety interventions. A key innovation of this methodology is the integration of cost–benefit analysis to prioritize interventions, ensuring optimal resource allocation. The approach was tested in a medium-sized Italian city where it helped identify critical areas and assess the potential impact of various safety measures, such as intersection redesign and traffic-calming strategies. The results demonstrated a significant potential to reduce accidents and associated social costs, offering a scalable model for urban road safety planning. By integrating data-driven insights with proactive evaluation, this methodology supports urban administrations in implementing effective, targeted interventions that contribute to Vision Zero goals
Obstructive Sleep Apnoea (OSA) and early atherosclerosis: The role of microbiota and EVs
No full textGut–lung Microbiota Interactions in Chronic Obstructive Pulmonary Disease (COPD): Potential Mechanisms Driving Progression to COPD and Epidemiological Data
No full textThis paper focuses on the gut–lung axis in the context of Inflammatory Bowel Disease (IBD) and Chronic Obstructive Pulmonary Disease (COPD), highlighting the key role played by microbial dysbiosis and the impact of environmental and genetic factors on the innate and acquired immune system and on chronic inflammation in the intestinal and pulmonary tracts. Recent evidence indicates that Antigen-Presenting Cells (APCs) perform regulatory activity influencing the composition of the microbiota. APCs (macrophages, dendritic cells, B cells) possess membrane receptors known as Pattern Recognition Receptors (PRRs), a category of toll-like receptors (TLRs). PRRs recognise distinct microbial structures and microbial metabolites called Signals, which modulate the saprophytic microbial equilibrium of the healthy microbiota by recognising molecular profiles associated with commensal microbes (Microbe-Associated Molecular Patterns, MAMPs). During dysbiosis, pathogenic bacteria can prompt an inflammatory response, producing PAMPs (Pathogen-Associated Molecular Patterns) thereby activating the proliferation of inflammatory response cells, both local and systemic. This series of regulatory and immune-response events is responsible (together with chronic infection, incorrect diet, obesity, etc.) for the systemic chronic inflammation (SCI) known as “low-grade inflammation” typical of COPD and IBD. This review looks at immunological research and explores the role of the microbiota, looking at two recent clinical studies, SPIROMICS and AERIS. There is a need for further clinical studies to characterize the pulmonary microbiota and to obtain new information about the pathogenesis of lung disease to improve our knowledge and treatment strategies and identify new therapeutic targets
Neuropsychological and socio–cognitive deficits in patients with obstructive sleep apnea
No full textIntroduction: Patients with obstructive sleep apnea (OSA) suffer from several neurocognitive deficits. We investigated the cognitive and socio-cognitive profiles of patients with severe OSA, controlling for potentially relevant mediating variables (i.e. age, body-mass index, cognitive reserve and depression). Moreover, we studied the neuropsychological profile of a high-risk OSA phenotype characterized by severe OSA and severe nocturnal hypoxemia. Method: We assessed 29 previously untreated severe OSA patients with a mean age of 55.6 (± 9.9 years) and a mean apnea-hypopnea index (AHI) of 53.1 (± 17.4). A control group of 34 healthy participants was also enrolled. Participants completed an extensive neuropsychological battery that included social cognition, a relatively new investigation area among OSA patients. Data analysis: Data were analyzed with a Bayesian approach. Specifically, Bayesian ANCOVA was used to investigate whether the grouping variable could predict test performance. Age, body-mass index, cognitive reserve and state of depression were added as covariates to the null model to weight the effects of these potential confounding factors. Three groups were analyzed: healthy controls (H), OSA with severe apnea and severe nocturnal oxygen desaturation (D+), and OSA with severe apnea non-desaturators (D−). Performances on the various neuropsychological tests were treated as the dependent variables. Results: The results indicate that non-verbal reasoning, the theory of mind skills, and mental shifting ability were impaired in OSA patients. Patients with severe nocturnal hypoxemia underperformed compared to patients with the same severity of apnea but non-desaturators. Additionally, we observed a trend toward a worse performance among OSA desaturator patients in the following abilities: constructional ability, short term verbal memory, phonological fluency, and the ability to inhibit automatic and dominant responses. Conclusion: The data suggest a key role of hypoxemia in affecting cognitive functioning in OSA patients. Executive functions and the concomitant involvement of social cognition are particularly affected
Obstructive sleep apnea syndrome in the pediatric age: The role of the pneumologist
No full textOBJECTIVE: This review paper aims to summarize the current state of knowledge on the role of the pneumologist in the diagnosis and respiratory treatment of children affected by obstructive Sleep Disordered Breathing (SDB). MATERIALS AND METHODS: A literature review has been performed on the following topics: obstructive SDB and its clinical entities, indications for respiratory treatment of pediatric SDB, and Continuous Positive Airway Pressure (CPAP) and Noninvasive Positive Pressure Ventilation (NIPPV) treatment approach to obstructive SDB. RESULTS: OSDB is related to obesity, craniofacial pathologies, neuromuscular disorders and, most commonly, adenotonsillar hypertrophy. Adenotonsillectomy is the first-choice treatment in children with obstructive apnea secondary to adenotonsillar hypertrophy. CPAP and NIPPV are recommended in cases where Obstructive Sleep Apnea (OSA) persists after surgery or when surgery is contraindicated. Treatment interventions are usually implemented gradually by separately addressing each abnormality that would predispose to obstructive SDB, then reevaluating after each intervention to detect any residual disease and to assess the need for additional treatment. CONCLUSIONS: Many pediatric patients continue to experience problems and symptoms such as hypersomnia and apnea after adenotonsillectomy and need CPAP/NIPPV treatment. Current knowledge is still incomplete, especially with regard to the mechanisms of pathogenesis of pediatric OSA, the factors affecting pediatric OSA, and the phenotypic variability of the disease. A better understanding of these aspects would contribute to the development of new therapies
Current Classification Algorithms for Biomedical Applications
No full textIn this study we report the advances in supervised learning methods that have been devised to analyze medical data sets. As mining of data sets produced by medical equipments is becoming an increasingly challenging task, due to the size of the databases and the gradient of their update, new methods need to provide classification models that can handle the complexity of the problems. We start describing standard methods and we show how kernel methods, incremental learning algorithms and feature reduction techniques, applied to standard classification techniques, can be successfully used to discriminate biological and medical data sets. Among existing methods, we describe those that have their foundations in the statistical learning theory and have been successfully applied to the field. We provide numerical experiments based on publicly available data sets, and discuss results in terms of classification accuracy. Finally, we draw conclusions and outline future research direction
Obstructive sleep apnea syndrome in the pediatric age: the role of the otorhinolaryngologist
No full textOBJECTIVE: Obstructive sleep apnea (OSA) is the primary indication for tonsillectomy, one of the most common pediatric surgical procedures, commonly performed in association with adenoidectomy. The objective of this review article is to evaluate the role of the otorhinolaryngologist in pediatric OSA. MATERIALS AND METHODS: A literature review has been performed on the following topics: peculiarities of sleep-disordered breathing in pediatric age; discrimination of sleep disorders; adenotonsillar hypertrophy; surgical techniques; adjuvant surgical procedures. RESULTS: The role of the otorhinolaryngologist in pediatric OSA is important for the evaluation of the upper airways and of essential biometric and polysomnographic data and for indication and execution of appropriate surgical treatment. In the majority of healthy children, adenotonsillectomy for OSA results in a dramatic improvement in respiratory parameters as measured by polysomnography. When post-surgical residual OSA occurs, it is essential to monitor patients by means of drug-induced sleep endoscopy (DISE). CONCLUSIONS: Otolaryngologic assessment is of paramount importance to correctly classify a child with OSA. Correct inspection of the upper airway and quantification of the quality of sleep through polysomnography lead to the right therapeutic choice. Knowledge of different surgical techniques helps to deal with residual OSA after studying the obstruction sites by drug-induced sedation endoscopy
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