197,278 research outputs found
Efficient NIZK Arguments with Straight-Line Simulation and Extraction
No full textNon-interactive zero-knowledge (NIZK) arguments allow a prover to convince a verifier about the truthfulness of an NP -statement by sending just one message, without disclosing any additional information. In several practical scenarios, the Fiat-Shamir transform is used to convert an efficient constant-round public-coin honest-verifier zero-knowledge proof system into an efficient NIZK argument system. This approach is provably secure in the random oracle model, crucially requires the programmability of the random oracle and extraction works through rewinds. The works of Lindell [TCC 2015] and Ciampi et al. [TCC 2016] proposed efficient NIZK arguments with non-programmable random oracles along with a programmable common reference string. In this work we show an efficient NIZK argument with straight-line simulation and extraction that relies on features that alone are insufficient to construct NIZK arguments (regardless of efficiency). More specifically we consider the notion of quasi-polynomial time simulation proposed by Pass in [EUROCRYPT 2003] and combine it with simulation and extraction with non-programmable random oracles thus obtaining a NIZK argument of knowledge where neither the zero-knowledge simulator, nor the argument of knowledge extractor needs to program the random oracle. Still, both the simulator and the extractor are straight-line. Our construction uses as a building block a modification of the Fischlin’s transform [CRYPTO 2005] and combines it with the concept of dense puzzles introduced by Baldimtsi et al. [ASIACRYPT 2016]. We also argue that our NIZK argument system inherits the efficiency features of Fischlin’s transform, which represents the main advantage of Fischlin’s protocol over existing schemes
Features of the Rho-dependent transcription termination polar element within the hisG cistron of Salmonella typhimurium
No full textPrevious genetic analysis showed that the polar effects of mutations in the hisG cistron of Salmonella typhimurium are dependent on the presence of a single putative transcription termination element within the hisG gene. In fact, all proximal mutations causing translation termination are strongly polar, whereas distal ones are not. The element was mapped by isolating mutations able to relieve the polar phenotype, and they were found to be small deletions in the region downstream of the translational stop codon (M. S. Ciampi and J. R. Roth, Genetics 118:193-202, 1988). In this study, we analyzed the his-specific RNAs synthesized in vivo in different strains harboring the polar frameshift hisG2148 mutation. The nature of the polarity effects is clearly transcriptional, since shorter RNA molecules were produced. When the hisG2148 mutation was transferred in a rho background or in strains harboring the small distal deletions, an increase in readthrough transcription was observed. The transcriptional termination element was characterized in more detail by performing high-resolution S1 nuclease mapping experiments. This analysis showed that (i) termination or exonucleolytic degradation following termination produced transcripts with heterogeneous 3' ends; (ii) this process is dependent on the transcription termination factor Rho, since relief of termination occurs in a rho background; and (iii) the element appears to function as a transcription terminator, at least to some extent, even in the course of active translation of the hisG cistron
Tipologie di mobilità a Roma: una cluster analysis
No full textTra i principali obiettivi che le città del futuro dovranno porsi vi è senza dubbio quello della mobilità sostenibile, intesa non come mero concetto di trasporto e movimento fisico, ma come vision alternativa, capace di favorire nuovi habitus finalizzati alla “decongestione urbana”, con il conseguente miglioramento della qualità della vita collettiva. Per rispondere alle istanze di maggiore vivibilità provenienti dalle comunità sociali, le nostre politiche urbane – nel solco di quelle sperimentate soprattutto nel nord Europa - dovranno prevedere e realizzare progetti innovativi, potenziare le performance delle realtà urbane e creare spazi di relazione, oltre che di scorrimento. In uno scenario ecosostenibile così prefigurato migliorerebbero non solo le condizioni di fruibilità degli spazi pubblici urbani, ma anche gli stili di vita e lo stato di salute dei cittadini.
Da queste premesse muove l’indagine empirica qui presentata e che afferisce al Progetto Prin “La città come cura e la cura della città. Salute e benessere: scenari della trasformazione urbana”, il cui obiettivo interdisciplinare è di comprendere in quali modi lo spazio urbano possa sollecitare comportamenti e abitudini diversi nel cittadino, incoraggiandone o meno il naturale movimento negli spostamenti quotidiani, con indubbi effetti in termini sanitari. La ricerca si rivolge alla popolazione attiva della Sapienza, per indagarne i comportamenti attinenti alla mobilità e poi riconnetterli agli stili di vita e allo stato di salute individuali. La popolazione analizzata, per quanto specifica, costituisce un campione e un settore urbano di indubbio interesse sul piano comunitario. Fin dai primi risultati emerge infatti un’evidente propensione alla mobilità sostenibile, a fronte della complessa morfologia territoriale di una città come Roma
Burn performance of fast ignited, tritium-poor ICF fuels
No full textThe potentials of fuels that are predominantly deuterium, with a small tritium content (tritium-poor deuterium), are examined in the context of the inertial confinement fusion (ICF) scheme known as 'fast ignitor', which is based on external heating of a portion of a precompressed target. For this purpose, the burn performance of compressed spheres of pure or nearly pure deuterium with an off-centre deuterium-tritium (DT) seed, ignited by an ultrapowerful external beam, has been studied using two dimensional (2-D) numerical simulations. The dependences of the fuel energy gain on the fuel mass and energy, and on the tritium fractional content F-T, have been studied; Limiting gain curves have been obtained for fixed values of F-T and of the isentrope parameter a. It is found that assemblies with F-T = 0.5-1%, fuel mass m approximate to 20 mg, compressed at density rho approximate to 1000 g/cm(3), can achieve tritium self-sufficiency (i.e. net tritium production). At alpha approximate to 1.5, the corresponding fuel energy at ignition is of the order of 1 MJ and the fuel energy gain can be about 1000. The potentials of tritium-poor configurations are also compared with those of equimolar DT fuels with different ignition configurations
Forme dell'abitare. Un'analisi sociologica dello spazio borghese
No full textLo studio sulle Forme dell’abitare parte dal presupposto che tra il corpo e lo spazio vi sia una relazione di coappartenenza e si attivi una comunicazione che diviene fortemente significativa nella casa, luogo dell’identità e della memoria, dell’esperienza personale e intersoggettiva. L’autrice analizza i modelli abitativi che accompagnano la borghesia in ascesa dell’Ottocento e quella avanzata del Novecento; essi, infatti, restituiscono fedelmente e processualmente il “volto” dell’individuo e della classe sociale di appartenenza. Nella casa del borghese si collocano e si cristallizzano i valori in cui egli si identifica e che caratterizzano la sua vita privata e pubblica: razionalità, ordine, solidità familiare, relazione con Alter, definizione dei ruoli e condivisione dello status. Quello della casa è un bisogno individuale e collettivo che mobilita e contiene dinamiche fisiche, psichiche, antropologiche, sociali e culturali: l’abitazione garantisce – a livello simbolico e materiale – la “fissità” necessaria ad allontanare il senso di spaesamento e sradicamento che caratterizza l’individuo-flâneur contemporaneo
A mathematical model for the behaviour of buildings subject to thermal field with stochastic component
No full textEquilibrium Based Iterative Solutions for the Nonlinear Beam Problem
No full textThe paper describes a procedure for the non-linear analysis of structures which are an assemblage of beams
with material non-linearities of general type; the approach uses the equilibrium integrals and a consistent
iterative formulation at the element level, within the general framework of the displacement method for the
solution of the global structural problem. The application of dierent approaches to the non-linear beam
problem is presented and discussed including the traditional stiness and
exibility approach and some mixed
formulations. The proposed equilibrium-based approach is shown to be more accurate and more robust than
the traditional compatibility-based approach, on which most of the non-linear beam elements available today
are based. Similar advantages are also found with respect to an approach based on the three-eld mixed
assumed strain method
- …
