664 research outputs found
Risorse geotermiche in Etruria
No full textLe conoscenze tecniche alla base dello sfruttamento dei gacimenti metalliferi e la capacità di governare con vantaggio i corsi d'acqua come chiave per capire lo sviluppo della civiltà etrusca
Il caso dei Campi Flegrei : rappresentazioni della Terra nell'antichità
No full textLa varietà di fenomeni geotermici dei Campi Flegrei e le interpretazioni fornite nell'antichità sulla base delle diverse interpretazioni di fenomeni tellurici, bradisismo e eruzioni vulcaniche
Implementation and Performance Evaluation of LT and Raptor Codes for Multimedia Applications
No full textDigital fountains have changed the standard transmission paradigm. A digital fountain can encode and transmit an unlimited number of data packets until every user gets enough information to guarantee correct decoding. Multimedia broadcasting, emerging peer-to-peer applications are only two examples of many other scenarios where digital fountains can be successfully applied. In this paper practical implementation issues of two class of digital fountain codes, namely LT and Raptor codes, are analyzed. Moreover, the performance in terms of coding and decoding complexity is measured experimentally
The Role of Na+/Ca2+ Countertransport and Other Na+-Entry Routes in the Pathophysiology of Stroke.
No full textNa+ has a crucial role in neuronal osmoregulation and, therefore, its intracellular concentrations are strictly controlled by several homeostatic systems, the most important of which is the Na+/K+ ATPase. A marked increase in [Na+]i takes place after ischemic insults in neurons where it has a crucial role in triggering necrotic and, perhaps, also apoptotic cell death. While the impairment in Na+/K+ ATPase activity contributes to this process, it is not sufficient per se to cause the massive intracellular Na+ overload observed after ischemia which requires, instead, also a significant increase in Na+ influx into the cell or an impairment of Na+ efflux. Traditionally, the increase in Na+ permeability occurring in ischemic neurons was ascribed to the activation of voltage-gated Na+ channels and/or of glutamate receptors, and their pharmacological blockade was proposed as a therapeutic strategy in stroke but did not meet the expectations. More recently, the spotlight was turned on NCX, ASICs, NHE, and NKCC, a group of ion channels and transporters, which, because of their specific mechanisms of activation, could represent a preferential Na+ influx or efflux route in ischemic neurons. Evidence suggesting their involvement in stroke and the possible benefits of their pharmacological modulation in this condition are reviewed in the present chapter
Sliding-window Raptor codes for efficient scalable wireless video broadcasting with unequal loss protection
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