Studio sperimentale di un motore monocilindrico con iniezione diretta a due stadi di idrogeno

Il presente lavoro di tesi si colloca all'interno di un'attività di ricerca finalizzata allo sviluppo di un innovativo sistema di iniezione diretta di idrogeno a bassa pressione ideato e svolto presso il Dipartimento di Energetica “L. Poggi” della Facoltà di Ingegneria di Pisa sotto la supervisione del Prof. Ing. Roberto Gentili. In particolare, il presente elaborato ha avuto come obiettivo principale lo studio sperimentale di un motore monocilindrico equipaggiato con il suddetto sistema di iniezione diretta a due stadi di idrogeno

Read my Feed – from RSS to SIP

Abstract: RRS web feeds are read by a synthetic voice, trough a SIP VoIP call, offering eye-free access to huge amount of classified textual content available on the Web. DTMF browsing allows to choose in between different RSS providers, and to cycle trough RRS titles, until the desired full article is selected, and read. The main content in the page is located by explicit parsing for known feeds, or by heuristic reasoning for new feeds and pages, which can be directly accessed by passing their URI as a SIP address parameter. Scalability is attained by caching of network and audio data instances, and expressivity improved by generation of SSML markup on the basis of the original HTML and CSS code. The whole system is made of a collection of Open Source components and public W3C standards, and the use of Festival for Speech Synthesis makes the service available for any supported language

Sistemi di telecomunicazione

Vengono studiate le tecniche di modulazione analogica e numerica alla base dei sistemi di telecomunicazione, assieme alle tecniche di codifica dell'informazione e della trasmissione dei segnali su cavo, fibra ottica e onda radio, approfondendo quindi l'analisi del caso delle comunicazioni mobili e quello delle trasmissioni multi-antenna o MIMO, a cui è dedicato un intero nuovo capitolo. Sono affrontati gli aspetti della rappresentazione dei segnali passa-banda mediante inviluppo complesso, l'effetto dei fenomeni di distorsione lineare (e non) sulle prestazioni in presenza di rumore, la modulazione OFDM ed a spettro espanso. Si approfondisce quindi la teoria dell'informazione definendo la capacità di canale ed analizzando le tecniche di codifica a blocco, convoluzionale ed iterativa. Imposteremo quindi un modello circuitale in grado di caratterizzare la rumorosità di apparati e ripetitori, ed affronteremo una rassegna delle tecniche di equalizzazione adottate a contrasto degli effetti filtranti. Infine, è inclusa la trattazione della teoria del traffico e delle reti a commutazione di pacchetto (inclusa Internet) e di circuito

Teoria dei segnali

Il testo tratta argomenti alla base dell'ingegneria delle telecomunicazioni, i cui aspetti sistemistici vengono approfonditi in un diverso volume. Affronteremo quindi l'analisi spettrale di Fourier e le proprietà associate, assieme al suo impiego nell'analisi dei sistemi lineari quando attraversati da segnali certi od aleatori. Dopo aver affrontato gli aspetti legati al processo di campionamento e quantizzazione dei segnali analogici vengono introdotte le metodologie di elaborazione digitale e filtraggio numerico, mentre lo studio della correlazione tra valori di segnale presi ad istanti diversi, e delle sue applicazioni alla analisi spettrale ed al filtraggio di segnali aleatori, è preceduto da un capitolo su probabilità e statistica. Sono quindi definiti ed analizzati i peggioramenti della qualità di un segnale causati da distorsione lineare (e non) e da disturbi additivi, a cui segue un capitolo riguardante la basi della teoria dell'informazione e della codifica di sorgente, per concludere con il capitolo che illustra le tecniche ed i formati in uso per la codifica numerica di segnali multimediali

L’agire pedagogico e la “comunicazione formativa” per prevenire il burnout

Il presente contributo ha l’obiettivo di identificare come la comunicazione possa essere indirizzata in un’ottica costruttiva al fine di preservare ed arricchire le relazioni personali e fungere così da fattore protettivo rispetto alle condizioni di burnout. La comunicazione, se opportunamente gestita, ha, infatti, un ruolo essenziale nella prevenzione e nella gestione di situazioni conflittuali all’interno del contesto lavorativo, tanto che si può parlare di comunicazione preventiva. L’arte di essere con l’altro (cioè la capacità di ascoltare, di essere empatici e di dare e ricevere feedback) diviene allora un’arte di cui tutti dovremmo disporre e di cui la formazione deve farsi carico

In vitro protein-DNA interactions at the human lamin B2 replication origin.

The complexity of mammalian origins of DNA replication has prevented, so far, the in vitro studies of the modalities of initiator protein binding and origin selection. We approached this problem by utilizing the human lamin B2 origin, wherein the precise start sites of replication initiation have been identified and known to be bound in vivo by the origin recognition complex (ORC). In order to analyze the in vitro interactions occurring at this origin, we have compared the DNA binding requirements and patterns of the human recombinant Orc4 with those of preparations of HeLa nuclear proteins containing the ORC complex. Here we show that both HsOrc4 alone and HeLa nuclear proteins recognize multiple sites within a 241-bp DNA sequence encompassing the lamin B2 origin. The DNA binding activity of HeLa cells requires the presence of ORC and can be reproduced in the absence of all the other proteins known to be recruited to origins by ORC. Both HsOrc4 alone and HeLa nuclear proteins exhibit cooperative and ATP-independent binding. This binding covers nucleotides 3853-3953 and then spreads outward. Because this region contains the start sites of DNA synthesis as well as the area protected in vivo and preserves protein binding capacity in vitro after removal of a fraction of the protected region, we suggest that it could contain the primary binding site. Thus the in vitro approach points to the sequence requirements for ORC binding as a key element for origin recognition

Characterization of the DNA-unwinding activity of human RECQ1, a helicase specifically stimulated by human replication protein A.

The RecQ helicases are involved in several aspects of DNA metabolism. Five members of the RecQ family have been found in humans, but only two of them have been carefully characterized, BLM and WRN. In this work, we describe the enzymatic characterization of RECQ1. The helicase has 3' to 5' polarity, cannot start the unwinding from a blunt-ended terminus, and needs a 3'-single-stranded DNA tail longer than 10 nucleotides to open the substrate. However, it was also able to unwind a blunt-ended duplex DNA with a "bubble" of 25 nucleotides in the middle, as previously observed for WRN and BLM. We show that only short DNA duplexes (30 bp) can be unwound by RECQ1 alone, but the addition of human replication protein A (hRPA) increases the processivity of the enzyme (100 bp). Our studies done with Escherichia coli single-strand binding protein (SSB) indicate that the helicase activity of RECQ1 is specifically stimulated by hRPA. This finding suggests that RECQ1 and hRPA may interact also in vivo and function together in DNA metabolism. Comparison of the present results with previous studies on WRN and BLM provides novel insight into the role of the N- and C-terminal domains of these helicases in determining their substrate specificity and in their interaction with hRPA

Virtual dissection table in diagnosis and classification of Le Fort fractures: A retrospective study of feasibility

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Stochastic association of neighboring replicons creates replication factories in budding yeast

Peer reviewedPublisher PD

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London