148 research outputs found
Behavioral modeling of GaN-based power amplifiers: impact of electrothermal feedback on the model accuracy and identification
No full textIn this article, we discuss the accuracy of behavioral models in simulating the intermodulation distortion (IMD) of microwave GaN-based high-power amplifiers in the presence of strong electrothermal (ET) feedback. Exploiting an accurate self-consistent ET model derived from measurements and thermal finite-element method simulations, we show that behavioral models are able to yield accurate results, provided that the model identification is carried out with signals with wide bandwidth and large dynamics
Caulerpa taxifolia: an ecological problem transformed into a scientific information issue
No full text
Editorial: Image-based computational approaches for personalized cardiovascular medicine: improving clinical applicability and reliability through medical imaging and experimental data
No full textMedical Instruments & Bio-Inspired Technolog
Degree of irrationality of a very general Abelian variety
No full textConsider a very general abelian variety of dimension at least and an integer . We show that if the map has a -dimensional fiber then . This extends results of the second-named author which covered the cases . As a geometric application, we prove that any dominant rational map from a very general abelian -fold to has degree at least for , thus improving results of Alzati and the last-named author in the case of a very general abelian variety
Erratum: OncoScore: a novel, Internet-based tool to assess the oncogenic potential of genes
No full textScientific Reports 7: Article number: 46290; published online: 07 April 2017; updated: 22 May 2017 The original version of this Article incorrectly listed all author names in reverse. The author list now reads: Rocco Piazza, Daniele Ramazzotti, Roberta Spinelli, Alessandra Pirola, Luca De Sano, Pierangelo Ferrari, Vera Magistroni, Nicoletta Cordani, Nitesh Sharma & Carlo Gambacorti-Passerini.</jats:p
Subcanonical points on projective curves and triply periodic minimal surfaces in the Euclidean space
No full textA point p on a smooth complex projective curve C of genus g ≥ 3 is subcanonical if the divisor (2g-2)p is canonical. The subcanonical locus in the moduli space M_{g,1} described by pairs (C,p) as above has dimension 2g-1 and consists of three irreducible components. Apart from the hyperelliptic component, the other two components depend on the parity of h^0(C,(g-1)p), and their general points satisfy h^0(C,(g-1)p)=1 and 2, respectively. In this paper, we study the subloci of pairs (C,p) such that h^0(C,(g-1)p) ≥ r+1 and h^0(C,(g-1)p) has the same parity as r+1, for some non-negative integer r. In particular, we provide a lower bound on their dimension, and we prove its sharpness for r ≤ 3. As an application, we further give an existence result for triply periodic minimal surfaces immersed in the 3-dimensional Euclidean space, completing a previous result of the second author
Video-based Goniometer Applications for Measuring Knee Joint Angles during Walking in Neurological Patients: A Validity, Reliability and Usability Study
No full textEasy-to-use evaluation of Range Of Motion (ROM) during walking is necessary to make decisions during neurological rehabilitation programs and during follow-up visits in clinical and remote settings. This study discussed goniometer applications (DrGoniometer and Angles - Video Goniometer) that measure knee joint ROM during walking through smartphone cameras. The primary aim of the study is to test the inter-rater and intra-rater reliability of the collected measurements as well as their concurrent validity with an electro-goniometer. The secondary aim is to evaluate the usability of the two mobile applications. A total of 22 patients with Parkinson’s disease (18 males, age 72 (8) years), 22 post-stroke patients (17 males, age 61 (13) years), and as many healthy volunteers (8 males, age 45 (5) years) underwent knee joint ROM evaluations during walking. Clinicians and inexperienced examiners used the two mobile applications to calculate the ROM, and then rated their perceived usability through the System Usability Scale (SUS). Intraclass correlation coefficients (ICC) and correlation coefficients (corr) were calculated. Both applications showed good reliability (ICC > 0.69) and validity (corr > 0.61), and acceptable usability (SUS > 68). Smartphone-based video goniometers could be used to assess the knee ROM during walking in neurological patients, because of their acceptable degree of reliability, validity and usability
Aortic valve neocuspidization and bioprosthetic valves: Evaluating turbulence haemodynamics
No full textAortic valve disease is often treated with bioprosthetic valves. An alternative treatment is aortic valve neocuspidization which is a relatively new reparative procedure whereby the three aortic cusps are replaced with patient pericardium or bovine tissues. Recent research indicates that aortic blood flow is disturbed, and turbulence effects have yet to be evaluated in either bioprosthetic or aortic valve neocuspidization valve types in patient-specific settings. The aim of this study is to better understand turbulence production in the aorta and evaluate its effects on laminar and turbulent wall shear stress. Four patients with aortic valve disease were treated with either bioprosthetic valves (n=2) or aortic valve neocuspidization valvular repair (n=2). Aortic geometries were segmented from magnetic resonance images (MRI), and 4D flow MRI was used to derive physiological inlet and outlet boundary conditions. Pulsatile large-eddy simulations were performed to capture the full range of laminar, transitional and turbulence characteristics in the aorta. Turbulence was produced in all aortas with highest levels occurring during systolic deceleration. In the ascending aorta, turbulence production is attributed to a combination of valvular skew, valvular eccentricity, and ascending aortic dilation. In the proximal descending thoracic aorta, turbulence production is dependent on the type of arch-descending aorta connection (e.g., a narrowing or sharp bend) which induces flow separation. Laminar and turbulent wall shear stresses are of similar magnitude throughout late systolic deceleration and diastole, although turbulent wall shear stress magnitudes exceed laminar wall shear stresses between 27.3% and 61.1% of the cardiac cycle. This emphasises the significance of including turbulent wall shear stress to improve our comprehension of progressive arterial wall diseases. The findings of this study recommend that aortic valve treatments should prioritise minimising valvular eccentricity and skew in order to mitigate turbulence generation
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