Search results for " Threshold"

2005

In this report we re-examine some recent experiments with digital organisms to test some predictions of quasispecies theory. These experiments revealed that under high mutation rates populations of less fit organisms previously adapted to such high mutation rates were able to outcompete organisms with higher average fitness but adapted to low mutation rates. We have verified that these results do hold in the original conditions and, by extending the set of initial parameters, we have also detected that the critical mutation rate was independent of population size, a result that we have found to be dependent on a different, contingent factor, the initial fitness vector. Furthermore, in all b…

Are smartphone applications (App) useful to improve hearing?

2020

Le App per smartphone possono essere utili per migliorare l’udito?L’obiettivo dello studio è quello valutare l’efficacia di un’App per smartphone creata con lo scopo di migliorare le performance uditive sia in soggetti normoudenti che in pazienti affetti da ipoacusia da lieve a severa. Si tratta di uno studio analitico multicentrico, eseguito tra giugno e dicembre 2017, che ha analizzato un campione di 68 pazienti di cui 55 ipoacusici e 13 normoudenti; a tutti i pazienti sono stati somministrati test audiologici specifici sia durante l’utilizzo della suddetta App che in assenza di ausili uditivi. Il protocollo di valutazione audiologica prevedeva l’esecuzione di un’audiometria tonale limina…

Digestive vacuole of Plasmodium falciparum released during erythrocyte rupture dually activates complement and coagulation.

2012

Abstract Severe Plasmodium falciparum malaria evolves through the interplay among capillary sequestration of parasitized erythrocytes, deregulated inflammatory responses, and hemostasis dysfunction. After rupture, each parasitized erythrocyte releases not only infective merozoites, but also the digestive vacuole (DV), a membrane-bounded organelle containing the malaria pigment hemozoin. In the present study, we report that the intact organelle, but not isolated hemozoin, dually activates the alternative complement and the intrinsic clotting pathway. Procoagulant activity is destroyed by phospholipase C treatment, indicating a critical role of phospholipid head groups exposed at the DV surfa…

Water structure in water/AOT/n-heptane microemulsions by FT-IR spectroscopy

1992

Abstract FT-IR spectra in the OH stretching region of water/sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/n-heptane microemulsions as a function of the water/AOT molar ratio (R) and of the weight fraction (φ) of the micellar phase have been recorded at 25°C. After elimination of the unwanted CH contribution and correction for the water concentration, the shape of the normalized OH bands has been found to be dependent on R and practically independent of φ. The analysis of these bands in terms of “bound” and “bulk” water (representing, as a first approximation, the two water domains within the water pool) allowed the evaluation of the fraction (α) of the “bound” water as a function of R. A…

Refractive index of water-AOT-n-heptane microemulsions

1993

Refractive index measurements on water/AOT/n-heptane microemulsions as a function of the volume fraction ϕ of the dispersed phase (water plus AOT) and of the water/AOT molar ratio R have been performed at 25°C. The refractive index was found to vary monotonically with ϕ without any change in rate during the crossover of the percolation threshold. Such a behavior suggested that, well above the percolation threshold, the water-AOT-n-heptane microemulsions are still formed by water-containing AOT reversed micelles dispersed in the oil phase. The analysis of the experimental data allowed an evaluation the fraction of the water molecules bonded to the AOT head group as a function of R.

2015

Objective Dopamine is an endogenous neuromodulator in cortical circuits and the basal ganglia. In animal models of temporal lobe epilepsy (TLE), seizure threshold is modulated to some extent by dopamine, with D1-receptors having a pro- and D2-receptors an anticonvulsant effect. We aimed to extend our previously reported results on decreased D2/D3 receptor binding in the lateral epileptogenic temporal lobe and to correlate them with demographic and seizure variables to gain a more comprehensive understanding of the underlying involvement of the dopaminergic system in the epileptogenesis of TLE. Methods To quantify D2/D3 receptor binding, we studied 21 patients with TLE and hippocampal sclero…

Class-B two-photon Fabry–Pérot laser

1998

Abstract We study the stationary operation and stability properties of a class-B two-photon Fabry–Perot laser. We show that, differently from the one-photon laser, the intensity emitted by the two-photon laser is larger in a Fabry–Perot than in a ring cavity. The lasing solution loses stability through a subcritical Hopf bifurcation, as it occurs in the unidirectional ring laser. The stability domain in the parameter space is larger in the Fabry–Perot than in the ring cavity configuration.

Progress in Modelling Coherently Pumped Far-Infrared Laser Dynamics

1990

Coherently pumped lasers (CPL) operating in the far-infrared spectral region shown a wealth of instabilities1, including a behavior remarkably similar2,3 with the predictions of the paradigmatic Lorenz-Haken model of a single-mode homogeneously broadened laser4,5. The qualitative agreement; between theory and experiments2,3 was rather surprising, for the model4,5 refers to a two-level system whereas the CPL operate on a three-level scheme, where the pumping and lasing transitions share a common upper level. Dupertuis et al.6 have identified conditions for the mathematical reduction of the CPL equations to the Lorenz-Haken equations4, but these conditions were not all fulfilled in the experi…

La casa Ipertestuale - Stanze e spazio-soglia

2010

Stanze e spazio soglia Il saggio descrive i risultati di un'esperienza di seminario/workshop extracurriculare, svoltosi a Palermo nel 2005 (dal titolo: “Futura. Come abiteremo domani”). La metafora dell’ipertesto, spesso utilizzata da architetti, filosofi e urbanisti come metafora significativa per descrivere la condizione metropolitana contemporanea, risulta particolarmente efficace quale rappresentazione sintetica dell’idea di casa che abbiamo inteso indagare, per alcune sue qualità essenziali che trovano immediato riscontro nelle nuove modalità dell’abitare. All’interno del tema più generale della casa “ipertestuale”, la sperimentazione diretta dal Emanuele Palazzotto ha inteso esplorare…

LA QUESTIONE ABITATIVA TRA SOSTENIBILITÀ SOCIALE E DINAMICHE IMMOBILIARI

2017

Questo studio si propone di delineare una metodologia di valutazione dell’housing affordability alla scala territoriale, intesa come accessibilità finanziaria all’abitazione, in modo da ottenere un sistema di informazioni da impiegare a supporto del processo decisionale pubblico sulle politiche abitative. L’obiettivo, in particolare, è quello di individuare la domanda locale e i bisogni sociali corrispondenti alla distribuzione territoriale dei gap reddituali che impediscono l’accesso all’abitazione, in modo da intervenire con tutti gli strumenti che consentono di raggiungere una maggiore equità sociale. La metodologia procede attraverso lo studio della distribuzione territoriale della ricc…