Noise Weighting in the Design of {\Delta}{\Sigma} Modulators (with a Psychoacoustic Coder as an Example)

A design flow for {\Delta}{\Sigma} modulators is illustrated, allowing quantization noise to be shaped according to an arbitrary weighting profile. Being based on FIR NTFs, possibly with high order, the flow is best suited for digital architectures. The work builds on a recent proposal where the modulator is matched to the reconstruction filter, showing that this type of optimization can benefit a wide range of applications where noise (including in-band noise) is known to have a different impact at different frequencies. The design of a multiband modulator, a modulator avoiding DC noise, and an audio modulator capable of distributing quantization artifacts according to a psychoacoustic model are discussed as examples. A software toolbox is provided as a general design aid and to replicate the proposed results.Comment: 5 pages, 18 figures, journal. Code accompanying the paper is available at http://pydsm.googlecode.co

Output Filter Aware Optimization of the Noise Shaping Properties of {\Delta}{\Sigma} Modulators via Semi-Definite Programming

The Noise Transfer Function (NTF) of {\Delta}{\Sigma} modulators is typically designed after the features of the input signal. We suggest that in many applications, and notably those involving D/D and D/A conversion or actuation, the NTF should instead be shaped after the properties of the output/reconstruction filter. To this aim, we propose a framework for optimal design based on the Kalman-Yakubovich-Popov (KYP) lemma and semi-definite programming. Some examples illustrate how in practical cases the proposed strategy can outperform more standard approaches.Comment: 14 pages, 18 figures, journal. Code accompanying the paper is available at http://pydsm.googlecode.co

Should {\Delta}{\Sigma} Modulators Used in AC Motor Drives be Adapted to the Mechanical Load of the Motor?

We consider the use of {\Delta}{\Sigma} modulators in ac motor drives, focusing on the many additional degrees of freedom that this option offers over Pulse Width Modulation (PWM). Following some recent results, we show that it is possible to fully adapt the {\Delta}{\Sigma} modulator Noise Transfer Function (NTF) to the rest of the drive chain and that the approach can be pushed even to a fine adaptation of the NTF to the specific motor loading condition. We investigate whether and to what extent the adaptation should be pursued. Using a representative test case and extensive simulation, we conclude that a mild adaptation can be beneficial, leading to Signal to Noise Ratio (SNR) improvements in the order a few dB, while the advantage pushing the adaptation to the load tracking is likely to be minimal.Comment: Sample code available at http://pydsm.googlecode.co

A sudden onset of parossistic atrial fibrillation

A 67 years old woman with a medical history notable for arterial hypertension presented with sudden onset of parossistic atrial fibrillation and shortness of breath. On examination, she appeared in good health condition. The blood pressure was 155/85 mm Hg, the pulse 125 beats per minute and the axillary temperature 36.5°C; the respirations were 24 breaths per minute. There was a grade 3/6 holosystolic murmur above the cardiac apex radiating posteriorly. Electrocardiography confirmed the presence of parossistic atrial fibrillation (Figure 1); a transthoracic echocardiography revealed a mass (3.4 by 7.8 cm) (Figure 2) attached to the left atrial septum and protruding through the mitral valve into the left ventricle, suggestive of a myxoma. Given the risk of systemic embolization and sudden syncope, the patient underwent prompt surgical resection of the mass (Figure 3). Pathological evaluation revealed a benign myxoma (Figure 4). The patient had a postoperative good course and was discharged home on the seventh postoperative day

Role of SIRT3 in Microgravity Response: A New Player in Muscle Tissue Recovery

Life on Earth has evolved in the presence of a gravity constraint. Any change in the value of such a constraint has important physiological effects. Gravity reduction (microgravity) alters the performance of muscle, bone and, immune systems among others. Therefore, countermeasures to limit such deleterious effects of microgravity are needed considering future Lunar and Martian missions. Our study aims to demonstrate that the activation of mitochondrial Sirtuin 3 (SIRT3) can be exploited to reduce muscle damage and to maintain muscle differentiation following microgravity exposure. To this effect, we used a RCCS machine to simulate microgravity on ground on a muscle and cardiac cell line. During microgravity, cells were treated with a newly synthesized SIRT3 activator, called MC2791 and vitality, differentiation, ROS and, autophagy/mitophagy were measured. Our results indicate that SIRT3 activation reduces microgravity-induced cell death while maintaining the expression of muscle cell differentiation markers. In conclusion, our study demonstrates that SIRT3 activation could represent a targeted molecular strategy to reduce muscle tissue damage caused by microgravity

Bone and body composition analyzed by Dual-energy X-ray Absorptiometry (DXA) in clinical and nutritional evaluation of young patients with Cystic Fibrosis: a cross-sectional study

<p>Abstract</p> <p>Background</p> <p>the improved general therapy has led to reduced morbidity and mortality from Cystic Fibrosis (CF), and bone status may have a potentially greater clinical impact.</p> <p>We investigated the correlation between the severity of the clinical condition, bone status and body composition parameters, in a group of children and young adults with CF.</p> <p>Methods</p> <p>we measured lumbar spine bone density and total body composition by dual energy x-ray absorptiometry (DXA) in 82 consecutive CF patients (42 males; median age: 13 years - range: 5-30). Eighty-two healthy subjects, matched for age, gender, height and pubertal stage were recruited as a control group.</p> <p>Results</p> <p>37 patients (45.1%) had a normal bone mineral density (BMD). A BMD reduction were observed in 45 (54.8%) patients. Lumbar spine Z score was positively related to Body Mass Index (BMI) and a higher Shwachman-Kulczycki score, and negatively related to Crispin-Norman score. A positive and significant correlation was also observed between lumbar spine Z score and total body composition.</p> <p>Conclusion</p> <p>a significant BMD reduction can be present early in CF children and adolescents. A careful follow up of bone status is required starting in childhood.</p

Progettazione e sviluppo di un gelato industriale

Iniziando nel 2016 come operaio miscelatore di un’industria alimentare fui trasferito poco dopo al reparto di R&D; da qui attraverso l’applicazione delle nozioni apprese durante il periodo universitario passai da tecnico di reparto fino a ricoprire il ruolo di responsabile del reparto di Ricerca & Sviluppo. Questa tesi pertanto affronta la tematica riguardante la progettazione di un prodotto alimentare usando sempre come caposaldo le nozioni di chimica necessarie anche allo svolgimento della professione del farmacista preparatore. La tesi prende in esame ogni singolo aspetto dello sviluppo di un nuovo gelato, a partire dall’analisi delle normative vigenti e delle certificazioni volontarie di un’industria atte alla produzione di prodotti destinati al consumo alimentare, al riconoscimento di prassi igienico sanitarie a livello mondiale, alle certificazioni ottenute, che oltre ad essere delle vere e proprie garanzie di gestione della qualità, sono necessarie per l’ingresso in mercati di nicchia. Successivamente si discute dal punto di vista chimico ogni singolo ingrediente che compone la miscela, con particolare riferimento alle caratteristiche fisiche ed organolettiche, alla funzione e all’utilizzo, per poi passare ai processi produttivi necessari alla produzione di un prodotto funzionale, ma soprattutto microbiologicamente idoneo al consumo. Affrontate queste tematiche, applicheremo queste nozioni allo sviluppo di un gelato vero e proprio studiando tutta la procedura, dalle motivazioni che spingono a sviluppare il nuovo prodotto alle problematiche affrontate. In questi capitoli vedremo, oltre allo sviluppo della ricetta in sé, tutti gli aspetti che riguardano il processo dello sviluppo di un nuovo prodotto e che quindi variano dalla stesura dell’etichetta, con lista ingredienti e tabella nutrizionale, allo studio del miglior confezionamento e pancalizzazione possibile; tutti questi parametri sono poi trasferiti all’interno di un modulo che permetterà di fornire un costo indicativo di produzione, che sarà la base da cui il reparto Commerciale analizzerà i possibili prezzi di uscita sul mercato del prodotto. Tutti questi passaggi sono una prassi per qualsiasi nuovo prodotto sviluppato. Successivamente analizzeremo le possibilità di consumo di questo gelato ideato appositamente per gli allergici al latte e per gli intolleranti al lattosio, parlando quindi sommariamente di queste due reazioni avverse all’alimento. Andremo a conoscere e spiegare le analisi necessarie alla conferma dell’assenza vera e propria dell’allergene indicato e illustreremo i prodotti di sanificazione usati per la produzione di un alimento microbiologicamente pulito

Teaching ΔΣ modulators with PyDSM and scientific Python

This paper reports on the introduction in circuits and systems education of a software toolbox named PyDSM, dedicated to the experimentation on ΔΣ modulators with particular emphasis on their noise shaping features, digital implementations and simulation. The toolbox has been tried on field for a half day tutorial at the ICECS 2014 conference, and is being gently proposed to students of the Master Degree in Electronics and Telecommunications Engineering at the University of Bologna. In addition to the value that the toolbox has in itself, it is also the premise to test, on a restricted topic, the potential of scientific Python in circuits and systems education

Teaching \u394\u3a3 modulators with PyDSM and scientific Python

This paper reports on the introduction in circuits and systems education of a software toolbox named PyDSM, dedicated to the experimentation on \u394\u3a3 modulators with particular emphasis on their noise shaping features, digital implementations and simulation. The toolbox has been tried on field for a half day tutorial at the ICECS 2014 conference, and is being gently proposed to students of the Master Degree in Electronics and Telecommunications Engineering at the University of Bologna. In addition to the value that the toolbox has in itself, it is also the premise to test, on a restricted topic, the potential of scientific Python in circuits and systems education