Desiderio e libertà: risposte ai miei critici

I argue that the two commentators, moving from different disciplinary backgrounds, deepen the comprehension of techo-nihilism and its relationships with contemporary social theory. From a philosophical point of view, P. Gomarasca offers a remarkable contribution in clarifying similarities and differences with respect to G.Deleuze's position, while Porta recovers two notions forgotten by the economic theory such as brotherhood and gift

Computational modelling to characterize dendrimer nanocarriers for siRNA delivery in chronic obstructive pulmonary disease

La Broncopneumopatia Cronica Ostruttiva (BPCO) è un’infiammazione polmonare progressiva caratterizzata da limitazione di flusso espiratorio. Ad oggi a livello mondiale si stima che 328 milioni di persone siano affette da BPCO e si prevede che diventi la quarta causa di morte entro il 2030 con più di 65 milioni di casi l’anno. Il successo dei trattamenti medici mediante acidi nucleici, come DNA e silencing interference RNA è fortemente legato al design di efficienti tecnologie di rilascio. I dendrimeri cationici rappresentano un’interessante possibilità come vettori grazie a noti vantaggi di efficienza, di basso costo, di produzione e di versatilità d’applicazione nel trattamento di molteplici malattie e disturbi. Il presente lavoro di tesi, svolto presso l’Istituto Dalle Molle di Studi sull’Intelligenza Artificiale di Lugano (CH), ha avuto lo scopo di investigare a livello computazionale su scala atomica il meccanismo di legame di diversi dendrimeri con un modello di siRNA, per l’ottenimento di efficienti sistemi di rilascio per il trattamento di BPCO. In primo luogo sono stati realizzati i modelli di tre dendrimeri con differente funzionalizzazione ed è stato eseguito uno studio preliminare di caratterizzazione in acqua. In seguito, mediante la dinamica molecolare è stato analizzato il complesso, esplorandone le caratteristiche di legame in termini energetici e strutturali. Si è evidenziato come i cambiamenti conformazionali e la presenza di cariche sulla superficie dei dendrimeri condizionassero il legame con il siRNA. La diversa funzionalizzazione dei dendrimeri infatti influisce fortemente sulla topologia e sulle proprietà fisico-chimiche che guidano l’interazione con gli agenti terapeutici e l’ambiente. I risultati di questo lavoro apportano un contributo significativo al futuro design di vettori di acidi nucleici selettivi, caratterizzati dal miglior compromesso tra stabilità del complesso e abilità di rilascio del sistema

Backscattering Differential Ghost Imaging in Turbid Media

In this Letter we present experimental results concerning the retrieval of images of absorbing objects immersed in turbid media via differential ghost imaging (DGI) in a backscattering configuration. The method has been applied, for the first time to our knowledge, to the imaging of small thin black objects located at different depths inside a turbid solution of polystyrene nanospheres and its performances assessed via comparison with standard imaging techniques. A simple theoretical model capable of describing the basic optics of DGI in turbid media is proposed.Comment: 5 pages, 6 figure

Three-dimensional coherence of light speckles: Experiment

We provide an experimental detailed study of the three-dimensional coherence properties of light speckles produced by different tunable pseudothermal sources. Our findings confirm the theoretical prediction of the companion article [A. Gatti et al., Phys. Rev. A 78, 063806 (2008)], according to which the longitudinal coherence of the speckles is ruled by ordinary diffraction laws only in the deep-Fresnel zone close to the source, deviates from this behavior in the Fresnel zone, and tends to become infinite when approaching the Fraunhofer zone. A quantitative comparison with theory is presented for Gaussian speckles in all the three regimes and for Airy speckles in the deep-Fresnel zone. Potential applications to three-dimensional imaging techniques are briefly discussed.We provide an experimental detailed study of the three-dimensional coherence properties of light speckles produced by different tunable pseudothermal sources. Our findings confirm the theoretical prediction of the companion article [A. Gatti , Phys. Rev. A 78, 063806 (2008)], according to which the longitudinal coherence of the speckles is ruled by ordinary diffraction laws only in the deep-Fresnel zone close to the source, deviates from this behavior in the Fresnel zone, and tends to become infinite when approaching the Fraunhofer zone. A quantitative comparison with theory is presented for Gaussian speckles in all the three regimes and for Airy speckles in the deep-Fresnel zone. Potential applications to three-dimensional imaging techniques are briefly discussed

Three-dimensional coherence of light speckles: Theory

We provide a detailed analysis of the three-dimensional spatial coherence properties of light speckles, based on very general assumptions. We show that, while in the deep Fresnel region close to the source the longitudinal coherence of speckles is ruled by the laws of ordinary diffraction, on approach to the Fraunhofer zone the longitudinal coherence length tends to become infinite. We offer both a quantitative and a qualitative description of the emergence of these different behaviors.We provide a detailed analysis of the three-dimensional spatial coherence properties of light speckles, based on very general assumptions. We show that, while in the deep Fresnel region close to the source the longitudinal coherence of speckles is ruled by the laws of ordinary diffraction, on approach to the Fraunhofer zone the longitudinal coherence length tends to become infinite. We offer both a quantitative and a qualitative description of the emergence of these different behaviors. \ua9 2008 The American Physical Society

Image transfer through a chaotic channel by intensity correlations

The three-wave mixing processes in a second-order nonlinear medium can be used for imaging protocols, in which an object field is injected into the nonlinear medium together with a reference field and an image field is generated. When the reference field is chaotic, the image field is also chaotic and does not carry any information about the object. We show that a clear image of the object be extracted from the chaotic image field by measuring the spatial intensity correlations between this field and one Fourier component of the reference. We experimentally verify this imaging protocol in the case of frequency downconversion.Comment: 17 pages, 7 figure

Differential Ghost Imaging

We present a new technique, differential ghost imaging (DGI), which dramatically enhances the signal-to-noise ratio (SNR) of imaging methods based on spatially correlated beams. DGI can measure the transmission function of an object in absolute units, with a SNR that can be orders of magnitude higher than the one achievable with the conventional ghost imaging (GI) analysis. This feature allows for the first time, to our knowledge, the imaging of weakly absorbing objects, which represents a breakthrough for GI applications. Theoretical analysis and experimental and numerical data assessing the performances of the technique are presented

Experimental evidence of high-resolution ghost imaging and ghost diffraction with classical thermal light

High-resolution ghost image and ghost diffraction experiments are performed by using a single source of thermal-like speckle light divided by a beam splitter. Passing from the image to the diffraction result solely relies on changing the optical setup in the reference arm, while leaving untouched the object arm. The product of spatial resolutions of the ghost image and ghost diffraction experiments is shown to overcome a limit which was formerly thought to be achievable only with entangled photons.Comment: 5 pages, 4 figure

Longitudinal coherence in thermal ghost imaging

We show theoretically and experimentally that lensless ghost imaging with thermal light is fully interpretable in terms of classical statistical optics. The disappearance of the ghost image when the object and the reference planes are located at different distances from the source is due to the fading out of the intensity-intensity cross correlation between the two planes. Thus the visibility and the resolution of the ghost image are determined by the longitudinal coherence of the speckle beam, and no quantum explanation is necessary.We show theoretically and experimentally that lensless ghost imaging with thermal light is fully interpretable in terms of classical statistical optics. The disappearance of the ghost image when the object and the reference planes are located at different distances from the source is due to the fading out of the intensity-intensity cross correlation between the two planes. Thus the visibility and the resolution of the ghost image are determined by the longitudinal coherence of the speckle beam, and no quantum explanation is necessary. \ua9 2008 American Institute of Physics