Application of a Simple, Spiking, Locally Competitive Algorithm to Radionuclide Identification

Many radionuclide identification algorithms use statistical inference to collect a variety of features from gamma-ray spectra to deduce the presence of particular radionuclides. More modern algorithms require large amounts of data to learn and use latent features from spectra for classification. Both approaches are computationally expensive, which is reflected in their power consumption, and require large amounts of user intervention to prepare. In this paper we introduce a low power, neuromorphic algorithm for the real-time identification of radionuclides which simultaneously considers the entire shape of a gamma-ray spectrum. Utilizing the output of a traditional gamma-ray detector, our spiking, locally competitive algorithm uses sparse coding optimization to compare global patterns in a gamma-ray spectrum with a dictionary of radionuclide templates. This approach allows us to model informative global features resulting from both photoelectric absorption and Compton scattering. For the purpose of radiation threat reduction, the dictionary consists of data from the Nuclear Wallet Cards, a list of radionuclides and their properties compiled by the National Nuclear Data Center. To test our algorithm we use a variety of gamma-ray spectra created using radionuclides measured under laboratory conditions with varying durations, distances, activity levels, and backgrounds, resulting in a wide range of signal to noise ratios. We have created test sets for three different gamma-ray detector types, with 57Co, 137Cs, 152Eu, 60Co, 239Pu, and 235U sources, to quantify the effect of resolution, efficiency, and background on the accuracy of the algorithm. We demonstrate a true positive accuracy of 91% with a high resolution detector and 89% with a low resolution detector on the corresponding test sets. Experimenting with the same radionuclides included in the test sets in a variety of special nuclear material (SNM) masking configurations, we show that our algorithm is capable of correctly identify both SNM and mask even when the activity level of the mask is several times higher than that of the SNM. We also determine that our algorithm achieves over a 99% reduction in power consumption over other radionuclide identification software applications, which is critical for long term, independent monitoring and is the goal of this research

L’occupazione anglo-americana e la ‘questione triestina’: Cinegiornali e documentari italiani del secondo dopoguerra.

Tra il 1945 e il 1954 Trieste e una parte dei territori della Venezia Giulia furono amministrati dall’Allied Military Government of Occupied Territories (AMGOT). La produzione documentaria e cinegiornalistica che racconta quel particolare periodo storico si offre oggi come strumento importante per analizzare e individuare le diverse forme di costruzione di una memoria nazionale condivisa. In particolare, la ricerca pone l’attenzione sui cinegiornali prodotti da La Settimana Incom e Nuova Luce, nonché sui documentari realizzati sotto l’egida dello United States Information Service, con lo scopo di individuare le caratteristiche principali del racconto storico offerto. I testi filmici presi in esame mostrano come, attraverso un processo selettivo e parziale del trascorso storico, venga definito e ridefinito il recente contesto bellico, favorendo un oblio dialogico ed estromettendo dal discorso qualsiasi senso di responsabilità nazionale. Inoltre, la ricostruzione storiografica e narrativa offerta dalle opere oggetto della ricerca se, da un lato, rafforza e promuove l’identità nazionale, dall’altro accentua la contrapposizione politica e ideologica tra il blocco occidentale e i paesi del Patto di Varsavia. In conclusione, la ricerca mostra il ruolo assunto da queste opere nella descrizione delle vicende del confine orientale, evidenziandone la natura politica e sottolineando la funzione svolta dalla produzione audiovisiva del secondo dopoguerra nel promuovere la costruzione di una “memoria istituzionale”

Long-term Outcomes after Islet Transplantation

Remarkable progress has occurred in clinical islet transplantation, and with over 1000 patients treated in the past 12 years, this therapy has moved from status of curiosity to realistic treatment for selected patients with type 1 diabetes complicated by refractory glycemic lability. The current chapter discusses indications for the procedure, provides a practical approach to optimal immunosuppressive and adjunctive management, discusses potential risks, long‐term outcomes and advances in post‐transplant treatment aimed at further moving this treatment closer to a potential cure, or at the very least, more widely available therapy, for diabetes