La visione a venire. Sul materialismo di Lucrezio e Spinoza

This paper investigates Lucretius and Spinoza’s materialism like a perspective oriented on the problem of the event. The first part, in particular, is dedicated to the discussion of the physical and ethical aspects of the Lucretian concept of clinamen, intended as the expression of an event that breaks the continuity of the uniform rectilinear motion of matter. The last part attempts to trace, within the Lucretian theory of simulacra, a path of emancipation of our ability to imagine, on the model of the theory of knowledge formulated by Spinoza in Ethics. The aim is to outline an idea of vision as an event in which the viewer takes shape together with what he sees

La creazione immaginaria

Dall'antichità ai giorni nostri il tema della creazione umana rimane un grande impensato nella storia della filosofia. L'elemento immaginario è la raccolta di quei saggi in cui Castoriadis ha cercato di riportare alla luce questo tema, vedendo nel tratto più essenziale, e al contempo oscuro dell'immaginazione, un potere di porre contenuti sensibili e intelligibili nuovi. Definire questo campo - progetto che in Castoriadis rimarrà incompiuto - implicherà il confronto con quegli autori che per primi riuscirono a scorgere le dinamiche creative, "radicali", dell'immaginazione umana. In tal senso, la concezione aristotelica dei phantasmata, i paradossi interni allo schematismo trascendentale di Kant e la teoria della fantasmatizzazione in Freud costituiscono il terreno da cui il filosofo greco propone di partire per pensare l’immaginazione come fonte di creazione

Furore Istituente. L'infinita rinascita del politico

In this text Giordano Bruno's philosophy is compared with aristotelian tradition and Thomas Hobbes' thought in a metapolitical perspective. The final part investigates the possibility of defining Bruno's political conception on the basis of the Deleuzian paradigm of institution

Perceptual learning improves contrast sensitivity, visual acuity, and foveal crowding in amblyopia

BACKGROUND: Amblyopic observers present abnormal spatial interactions between a low-contrast sinusoidal target and high-contrast collinear flankers. It has been demonstrated that perceptual learning (PL) can modulate these low-level lateral interactions, resulting in improved visual acuity and contrast sensitivity. OBJECTIVE: We measured the extent and duration of generalization effects to various spatial tasks (i.e., visual acuity, Vernier acuity, and foveal crowding) through PL on the target's contrast detection. METHODS: Amblyopic observers were trained on a contrast-detection task for a central target (i.e., a Gabor patch) flanked above and below by two high-contrast Gabor patches. The pre- and post-learning tasks included lateral interactions at different target-to-flankers separations (i.e., 2, 3, 4, 8λ) and included a range of spatial frequencies and stimulus durations as well as visual acuity, Vernier acuity, contrast-sensitivity function, and foveal crowding. RESULTS: The results showed that perceptual training reduced the target's contrast-detection thresholds more for the longest target-to-flanker separation (i.e., 8λ). We also found generalization of PL to different stimuli and tasks: contrast sensitivity for both trained and untrained spatial frequencies, visual acuity for Sloan letters, and foveal crowding, and partially for Vernier acuity. Follow-ups after 5-7 months showed not only complete maintenance of PL effects on visual acuity and contrast sensitivity function but also further improvement in these tasks. CONCLUSION: These results suggest that PL improves facilitatory lateral interactions in amblyopic observers, which usually extend over larger separations than in typical foveal vision. The improvement in these basic visual spatial operations leads to a more efficient capability of performing spatial tasks involving high levels of visual processing, possibly due to the refinement of bottom-up and top-down networks of visual areas

Independent sets in Line of Sight networks

Line of Sight (LoS) networks provide a model of wireless communication which incor-porates visibility constraints. Vertices of such networks can be embedded onto the cube{(x1,x2,...,xd):xi∈{1,...,n},1≤i≤d}so that two vertices are adjacent if and onlyif their images lay on a line parallel to one of the cube edges and their distance is lessthan a given range parameterω. In this paper we study large independent sets in LoSnetworks.Weprovethatthecomputationalproblemoffindingamaximumindependentset can be solved optimally in polynomial time for one dimensional LoS networks.However, ford≥2, the (decision version of) the problem becomes NP-complete for anyfixedω≥3. In addition, we show that the problem is APX-hard whenω=nford≥3.On the positive side, we show that LoS networks generalize chordal graphs. This impliesthat there exists a simpled-approximation algorithm for the maximum independent setproblem in LoS networks. Finally, we describe a polynomial time approximation schemefor the maximum independent set problem in LoS networks for the case whenωis aconstantandpresentanimprovedheuristicalgorithmfortheprobleminthecaseω=

It's not always varicocele: A strange case of Zinner syndrome

A 42-year-old man presented with a huge varicocele. The patient was completely asymptomatic and he did not complain of dysuria, perineal discomfort, or ejaculatory pain. During the visit, the mass mimicked a varicocele and during the Valsalva maneuver a reflux was documented by colour Doppler ultrasound and an abdominal ultrasound revealed an agenesis of the right kidney and a 4.5-cm diameter intra-prostatic cyst. An abdominal and pelvis magnetic resonance imaging was then performed, which confirmed the right renal agenesis, with an epididymal enlargement in the body and tail. This is a unique case of Zinner syndrome in which the patient presented with a paratesticular mass mimicking a varicocele. \ua9 2015 Canadian Urological Association

Separate motion-detecting mechanisms for first-and second-order patterns revealed by rapid forms of visual motion priming and motion aftereffect

Fast adaptation biases the perceived motion direction of a subsequently presented ambiguous test pattern (R. Keywords: rapid visual motion priming, rapid motion aftereffect, perceptual sensitization, first-order motion, second-order motion, cross-order motion, VMP, MAE Citation: Pavan, A., Campana, G., Guerreschi, M., Manassi, M., & Casco, C. (2009). Separate motion-detecting mechanisms for first-and second-order patterns revealed by rapid forms of visual motion priming and motion aftereffect

Dynamic Programming Optimization in Line of Sight Networks

Line of Sight (LoS) networks were designed to model wireless communication in settings which may contain obstacles. For fixed positive integer d, and positive integer ω, a graph is a (d-dimensional) LoS network with range parameter ω if it can be embedded in a finite cube of the d-dimensional integer grid so that each pair of vertices in V are adjacent if and only if their embedding coordinates differ only in one position and such difference is less than ω. In this paper we investigate a dynamic programming (DP) approach which can be used to obtain efficient algorithmic solutions for various combinatorial problems in LoS networks. In particular DP solves the Maximum Independent Set (MIS) problem in LoS networks optimally, for any ω, on narrow LoS networks (i.e. networks which can be embedded in a region, for some fixed k independent of n). In the unrestricted case it has been shown that the (decision version of the) problem is NP-hard when , for fixed . We describe how DP can be used as a building block in the design of good approximation algorithms in this case. In particular we present a semi-online polynomial-time approximation scheme for the MIS problem in narrow d-dimensional LoS networks, as well as a polynomial-time 2-approximation algorithm and a fast polynomial time approximation scheme for the MIS problem in arbitrary d-dimensional LoS networks. Finally we comment on how the approach can be adapted to prove similar results for a number of important optimization problems in LoS networks