La collaborazione digitale: un’analisi dei requisiti tecnologici e dei requisiti degli utenti

La digital collaboration è un modo di lavorare e interagire, tra operatori (knowledge workers) tra loro distanti, che si incontra in molti scenari applicativi e, frequentemente, nel campo della formazione. L’adozione di un regime di digital collaboration, tuttavia, non sempre corrisponde, negli stakeholders, a una consapevolezza dei vincoli e requisiti di questo tipo di approccio. La bontà di un’iniziativa di digital collaboration dipende sia dalle specifiche qualità dello strumento tecnologico adottato, sia dalla preparazione degli utenti. In questo lavoro, viene definito un insieme di requisiti essenziali per il design di tali spazi virtuali, ispirato alle soluzioni più avanzate. Parallelamente vengono analizzate alcune capacità essenziali (virtual interaction skills) che i partecipanti a questi spazi devono possedere per agire efficacemente. Ambedue questi insiemi di requisiti sono destinati a diventare sempre più stringenti ed estesi con l’evoluzione delle nuove tecnologie

Evaluation of lumbar pain with weight-bearing MRI: Preliminary experience.

PURPOSE/INTRODUCTION: To assess the usefulness of weight-bearing examination of the lumbar spine performed with a dedicated MRI scanner in the evaluation of patients with clinical evidence of lumbar pain. MATERIALS AND METHODS: Between August 2008 and July 2009, 40 patients with clinical evidence of lumbar pain (group A) and a similar number of healthy volunteers (group B) were submitted to MRI examination of lumbar spine. Spin echo T1w and fast spin echo T2w images were acquired with a 0.25 Tesla scanner (G-Scan, Esaote Spa, Genoa, Italy) in both weight-bearing position and conventional supine position. A dedicated receiving coil for the lumbar spine was used. Three radiologists, blinded on history and clinical examination of subjects, assessed, in consensus, variations of lumbar lordosis angle and presence of pathology on images acquired in both positions, in different sequences and in different planes. RESULTS: In group A, conventional supine MRI was positive for pathology in 30/40 cases while weight-bearing MRI was positive in 39/40 cases. In all cases of group B, no signs of pathology was found in both positions. Weight-bearing MRI showed modifications of lumbar lordosis angle in all cases of both groups in respect to conventional supine MRI. DISCUSSION/CONCLUSION: Imaging the lumbar spine in weight-bearing position with a dedicated MRI scanner and a dedicated coil could allow identification of pathology which could be overlooked if imaging patients only in the supine position

Digital collaboration: forme sociali in evoluzione

La collaborazione digitale, nel contesto di un’incalzante presenza di tutta una gamma di tecnologie digitali nella vita di tutti i giorni, è l’argomento del Capitolo 3 del libro “Orizzonti di conoscenza. Strumenti digitali, metodi e prospettive per l’uomo del terzo millennio” di Fortunato Sorrentino e Maria Chiara Pettenati, edito da Firenze University Press, 2014. Mantenendo fisso il punto focale del libro – la conoscenza nelle sue nuove forme, la sua creazione e condivisione nel mondo contemporaneo – questa modalità di collaborazione, sempre più adottata dal knowledge worker moderno, viene discussa nei vari scenari d’uso e osservata da molteplici punti di vista. Ricevono particolare attenzione gli strumenti per la collaborazione digitale, una generazione di applicazioni software innovative, i cosiddetti “spazi di lavoro virtuali condivisi”, insieme alla discussione delle abilità e delle attitudini richieste per avvalersi efficacemente di tali dispositivi

Parametric multi-objective optimization of an Organic Rankine Cycle with thermal energy storage for distributed generation

Abstract This paper focuses on the thermodynamic modelling and parametric optimization of an Organic Rankine Cycle (ORC) which recovers the heat stored in a thermal energy storage (TES). A TES with two molten-salt tanks (one cold and one hot) is selected since it is able to operate in the temperature range useful to recover heat from different sources such as exhaust gas of Externally Fired Gas Turbine (EFGT) or Concentrating Solar Power (CSP) plant, operating in a network for Distributed Generation (DG). The thermal storage facilitates a flexible operation of the power system operating in the network of DG, and in particular allows to compensate the energy fluctuations of heat and power demand, increase the capacity factor of the connected plants, increase the dispatchability of the renewable energy generated and potentially operate in load following mode. The selected ORC is a regenerative cycle with the adoption of a Heat Recovery Vapour Generator (HRVG) that recovers heat from molten salts flowing from the Hot Tank to the Cold Tank of the TES. By considering the properties of molten salt mixtures, a ternary mixture able to operate between 200 and 400 °C is selected. The main ORC parameters, namely the evaporating pressure/temperature and the evaporator/condenser pinch point temperature differences, are selected as variables for the thermodynamic ORC optimization. An automatic optimization procedure is set up by means of a genetic algorithm (GA) coupled with an in-house code for the ORC calculation. Firstly, a mono-objective optimization is carried out for two working fluids of interest (Toluene and R113) by maximization of the cycle thermal efficiency. Afterwards, a multi-objective optimization is carried out for the fluid with the best performance by means of a Non-dominated Sorting Genetic Algorithm (NSGA) in order to evaluate the cycle parameters which maximize the thermal efficiency and minimise the heat exchanger surface areas. Toluene results able to give the best trade-off between efficiency and heat exchanger dimensions for the present application, showing that by with respect to the best efficiency point, the heat exchange area can be reduced by 36% with only a penalty of 1% for the efficiency

Plantar fascia evaluation with a dedicated magnetic resonance scanner in weight-bearing position: our experience in patients with plantar fasciitis and in healthy volunteers.

Purpose. This study assessed the usefulness of upright weight-bearing examination of the ankle/hind foot performed with a dedicated magnetic resonance (MR)imaging scanner in the evaluation of the plantar fascia in healthy volunteers and in patients with clinical evidence of plantar fasciitis. Materials and methods. Between January and March 2009, 20 patients with clinical evidence of plantar fasciitis (group A) and a similar number of healthy volunteers (group B) underwent MR imaging of the ankle/hind foot in the upright weight-bearing and conventional supine position. A 0.25-Tesla MR scanner (G-Scan, Esaote SpA, Genoa, Italy) was used with a dedicated receiving coil for the ankle/hind foot. Three radiologists, blinded to patients’ history and clinical findings, assessed in consensus morphological and dimensional changes and signal intensity alterations on images acquired in both positions, in different sequences and in different planes.Results. In group A, MR imaging confirmed the diagnosis in 15/20 cases; in 4/15 cases, a partial tear of the plantar fascia was identified in the upright weight-bearing position alone. In the remaining 5/20 cases in group A and in all cases in group B, the plantar fascia showed no abnormal signal intensity. Because of the increased stretching of the plantar fascia, in all cases in group A and B, thickness in the proximal third was significantly reduced (p<0.0001) under upright weight-bearing compared with the supine position Conclusions. Imaging the ankle/hind foot in the upright weight-bearing position with a dedicated MR scanner and a dedicated coil might enable the identification of partial tears of the plantar fascia, which could be overlooked in the supine position

Community structure in real-world networks from a non-parametrical synchronization-based dynamical approach

This work analyzes the problem of community structure in real-world networks based on the synchronization of nonidentical coupled chaotic R\"{o}ssler oscillators each one characterized by a defined natural frequency, and coupled according to a predefined network topology. The interaction scheme contemplates an uniformly increasing coupling force to simulate a society in which the association between the agents grows in time. To enhance the stability of the correlated states that could emerge from the synchronization process, we propose a parameterless mechanism that adapts the characteristic frequencies of coupled oscillators according to a dynamic connectivity matrix deduced from correlated data. We show that the characteristic frequency vector that results from the adaptation mechanism reveals the underlying community structure present in the network.Comment: 21 pages, 7 figures; Chaos, Solitons & Fractals (2012

Effect of correlations on network controllability

A dynamical system is controllable if by imposing appropriate external signals on a subset of its nodes, it can be driven from any initial state to any desired state in finite time. Here we study the impact of various network characteristics on the minimal number of driver nodes required to control a network. We find that clustering and modularity have no discernible impact, but the symmetries of the underlying matching problem can produce linear, quadratic or no dependence on degree correlation coefficients, depending on the nature of the underlying correlations. The results are supported by numerical simulations and help narrow the observed gap between the predicted and the observed number of driver nodes in real networks

Emergence of structural patterns out of synchronization in networks with competitive interactions

Synchronization is a collective phenomenon occurring in systems of interacting units, and is ubiquitous in nature, society and technology. Recent studies have enlightened the important role played by the interaction topology on the emergence of synchronized states. However, most of these studies neglect that real world systems change their interaction patterns in time. Here, we analyze synchronization features in networks in which structural and dynamical features co-evolve. The feedback of the node dynamics on the interaction pattern is ruled by the competition of two mechanisms: homophily (reinforcing those interactions with other correlated units in the graph) and homeostasis (preserving the value of the input strength received by each unit). The competition between these two adaptive principles leads to the emergence of key structural properties observed in real world networks, such as modular and scale–free structures, together with a striking enhancement of local synchronization in systems with no global order

The Kuramoto model in complex networks

181 pages, 48 figures. In Press, Accepted Manuscript, Physics Reports 2015 Acknowledgments We are indebted with B. Sonnenschein, E. R. dos Santos, P. Schultz, C. Grabow, M. Ha and C. Choi for insightful and helpful discussions. T.P. acknowledges FAPESP (No. 2012/22160-7 and No. 2015/02486-3) and IRTG 1740. P.J. thanks founding from the China Scholarship Council (CSC). F.A.R. acknowledges CNPq (Grant No. 305940/2010-4) and FAPESP (Grants No. 2011/50761-2 and No. 2013/26416-9) for financial support. J.K. would like to acknowledge IRTG 1740 (DFG and FAPESP).Peer reviewedPreprin

Bowel preparation for elective colorectal resection: multi-treatment machine learning analysis on 6241 cases from a prospective Italian cohort

background current evidence concerning bowel preparation before elective colorectal surgery is still controversial. this study aimed to compare the incidence of anastomotic leakage (AL), surgical site infections (SSIs), and overall morbidity (any adverse event, OM) after elective colorectal surgery using four different types of bowel preparation. methods a prospective database gathered among 78 Italian surgical centers in two prospective studies, including 6241 patients who underwent elective colorectal resection with anastomosis for malignant or benign disease, was re-analyzed through a multi-treatment machine-learning model considering no bowel preparation (NBP; No. = 3742; 60.0%) as the reference treatment arm, compared to oral antibiotics alone (oA; No. = 406; 6.5%), mechanical bowel preparation alone (MBP; No. = 1486; 23.8%), or in combination with oAB (MoABP; No. = 607; 9.7%). twenty covariates related to biometric data, surgical procedures, perioperative management, and hospital/center data potentially affecting outcomes were included and balanced into the model. the primary endpoints were AL, SSIs, and OM. all the results were reported as odds ratio (OR) with 95% confidence intervals (95% CI). results compared to NBP, MBP showed significantly higher AL risk (OR 1.82; 95% CI 1.23-2.71; p = .003) and OM risk (OR 1.38; 95% CI 1.10-1.72; p = .005), no significant differences for all the endpoints were recorded in the oA group, whereas MoABP showed a significantly reduced SSI risk (OR 0.45; 95% CI 0.25-0.79; p = .008). conclusions MoABP significantly reduced the SSI risk after elective colorectal surgery, therefore representing a valid alternative to NBP