The weight of time: gravitational force enhances discrimination of visual motion duration

In contrast with the anisotropies in spatial and motion vision, anisotropies in the perception of motion duration have not been investigated to our knowledge. Here, we addressed this issue by asking observers to judge the duration of motion of a target accelerating over a fixed length path in one of different directions. Observers watched either a pictorial or a quasi-blank scene, while being upright or tilted by 45° relative to the monitor and Earth's gravity. Finally, observers were upright and we tilted the scene by 45°. We found systematic anisotropies in the precision of the responses, the performance being better for downward motion than for upward motion relative to the scene both when the observer and the scene were upright and when either the observer or the scene were tilted by 45°, although tilting decreased the size of the effect. We argue that implicit knowledge about gravity force is incorporated in the neural mechanisms computing elapsed time. Furthermore, the results suggest that the effects of a virtual gravity can be represented with respect to a vertical direction concordant with the visual scene orientation and discordant with the direction of Earth's gravity

All-Optical Reinforcement Learning in Solitonic X-Junctions

L'etologia ha dimostrato che gruppi di animali o colonie possono eseguire calcoli complessi distribuendo semplici processi decisionali ai membri del gruppo. Ad esempio, le colonie di formiche possono ottimizzare le traiettorie verso il cibo eseguendo sia un rinforzo (o una cancellazione) delle tracce di feromone sia spostarsi da una traiettoria ad un'altra con feromone più forte. Questa procedura delle formiche possono essere implementati in un hardware fotonico per riprodurre l'elaborazione del segnale stigmergico. Presentiamo qui innovative giunzioni a X completamente integrate realizzate utilizzando guide d'onda solitoniche in grado di fornire entrambi i processi decisionali delle formiche. Le giunzioni a X proposte possono passare da comportamenti simmetrici (50/50) ad asimmetrici (80/20) utilizzando feedback ottici, cancellando i canali di uscita inutilizzati o rinforzando quelli usati.Ethology has shown that animal groups or colonies can perform complex calculation distributing simple decision-making processes to the group members. For example ant colonies can optimize the trajectories towards the food by performing both a reinforcement (or a cancellation) of the pheromone traces and a switch from one path to another with stronger pheromone. Such ant's processes can be implemented in a photonic hardware to reproduce stigmergic signal processing. We present innovative, completely integrated X-junctions realized using solitonic waveguides which can provide both ant's decision-making processes. The proposed X-junctions can switch from symmetric (50/50) to asymmetric behaviors (80/20) using optical feedbacks, vanishing unused output channels or reinforcing the used ones

Archeologia delle aree montane europee: metodi, problemi e casi di studio

Negli ultimi anni, a livello europeo, si \ue8 assistito a un rinnovato interesse per le \u201cquestioni ambientali\u201d che ha investito tutte le scienze sociali. In questo contesto, la montagna e, pi\uf9 in generale, le aree interne sono al centro dell\u2019attenzione di specialisti di varie discipline. Tale interesse sta producendo, anche in archeologia, una corposa bibliografia dalla quale emergono, da un lato, la variet\ue0 degli approcci e delle metodologie messe in campo dai diversi gruppi di ricerca e, dall\u2019altro, le notevoli potenzialit\ue0 informative di queste aree, che hanno meno risentito delle conseguenze distruttive dei processi di urbanizzazione successivi al secondo dopoguerra. Il numero monografico 13 de \u201cIl Capitale Culturale\u201d accoglie sia studi di carattere metodologico e teorico, sia resoconti articolati di ricerche in corso in Europa, senza alcuna limitazione di carattere cronologico o di approccio, sui seguenti temi: \u2022 Approcci metodologici e teorici allo studio delle aree montane e/o interne; \u2022 Survey nelle aree montane; \u2022 Archeologia delle risorse ambientali; \u2022 Visibilit\ue0/ invisibilit\ue0 dei paesaggi montani nelle diverse fonti; \u2022 I paesaggi montani e i sistemi di gestione delle risorse ambientali; \u2022 Economie della montagna ed economie nella montagna; \u2022 Caratteri delle produzioni ceramiche; \u2022 Archeologia della produzione ed eventuali peculiarit\ue0 dei cicli produttivi; \u2022 Archeologia dell'edificato rurale storico; \u2022 Archeologia pubblica, valorizzazione dei Beni Archeologici e archeologia preventiva nelle aree montane

A Differential Mechatronic Device: Design, Simulation and Experimental Results

Differential mechanisms are widely studied in literature, from a theoretical viewpoint and for applicative reasons. A differential mechanism is a mechanical system with one or more output motions resulting from the combination of different input motions acting on the same degree of freedom. In this work, we point the attention on planar differential systems (a monoaxis and a Cartesian device) composed by belts and pulleys. Particularly the Vernier effect is used to realize high-speed and highaccuracy devices with low-cost components. Simplified models of these two systems are presented to show the main kinematic and dynamic features. An advanced model is then realized for the Cartesian device with the aid of the Dymola software and simulation results are compared with the expected ones from the simplified model. The control of the system is realized with three PI systems (proportionalintegrative) optimized via an adaptive logic. Finally early experimental results are presented only for the monoaxis system

Bibliografia

Abstract

Endocytic pathways and membrane recycling involve the actin filaments in tobacco pollen tubes

The pollen tube is a tip growing cell that plays a fundamental role in the fertilization process of higher plants. Pollen tube growth is based on transport and accumulation of secretory vesicles. The incorporation of new segments of PM largely exceeds the quantity of membrane required for the extension, so the excess of PM must be removed by endocytosis. Recent studies showed internalization of subapical PM domains that were mainly recycled to exocytosis through the Golgi apparatus and a second mainly degradative pathway involving PM retrieval at the tip. The movements of the endomembrane system during the pollen tube growth depends on the concerted action and integrity of the cytoskeleton. In this study we disturb the system of cortical actin filaments using Latrunculin B to verify modifications in endocytosis, using specific FM dyes in time-lapse experiments and by ultrastructural experiments using charged Nanogold. Our results demonstrate that the system of cortical microfilaments determines a strong reduction of endocytosis in the subapical regions and consequently the alteration of recycling through the Golgi and the inhibition of the degradative pathways

Magnetic and ground penetrating radar for the research of Medieval buried structures in Marche Region

A magnetic and Ground Penetrating Radar joint survey was carried out in the framework of the R.I.M.E.M. project that has the aim of supporting the archaeological prospections and drive the selection of the excavation areas related to the Late Roman Period and Early Middle Ages in the Central and Southern Italy. In particular, this papers deals with the magnetic surveys acquired near “Madonna della Valle” and GPR and magnetic joint surveys carried out in “Monastero”site. Most of magnetic maps carried out in “Madonna della Valle” site shown the absence of structured magnetic anomalies, despite of the presence of archaeological signs. Several hypothesis were given to explain this evidence. Joint interpretation performed in “Monastero” site shown more intense magnetic anomalies related with shallower reflections due to probably to buried pipes. Other reflections are related with magnetic anomalies compatible with archaeological targets, but some significant reflections do not correspond to any magnetic anomaly, indicating magnetic method could be “blind” respect the archaeological target. New field surveys including the electrical resistivity tomography could be carried out in order to overcome these acquisition and interpretation difficulties

The Change in Fingertip Contact Area as a Novel Proprioceptive Cue

Humans, many animals, and certain robotic hands have deformable fingertip pads [1, 2]. Deformable pads have the advantage of conforming to the objects that are being touched, ensuring a stable grasp for a large range of forces and shapes. Pad deformations change with finger displacements during touch. Pushing a finger against an external surface typically provokes an increase of the gross contact area [3], potentially providing a relative motion cue, a situation comparable to looming in vision [4]. The rate of increase of the area of contact also depends on the compliance of the object [5]. Because objects normally do not suddenly change compliance, participants may interpret an artificially induced variation in compliance, which coincides with a change in the gross contact area, as a change in finger displacement, and consequently they may misestimate their finger’s position relative to the touched object. To test this, we asked participants to compare the perceived displacements of their finger while contacting an object varying pseudo-randomly in compliance from trial to trial. Results indicate a bias in the perception of finger displacement induced by the change in compliance, hence in contact area, indicating that participants interpreted the altered cutaneous input as a cue to proprioception. This situation highlights the capacity of the brain to take advantage of knowledge of the mechanical properties of the body and of the external environment

Magnetic and ground penetrating radar for the research of Medieval buried structures in Marche Region

A magnetic and Ground Penetrating Radar joint survey was carried out in the framework of the R.I.M.E.M. project that has the aim of supporting the archaeological prospections and drive the selection of the excavation areas related to the Late Roman Period and Early Middle Ages in the Central and Southern Italy. In particular, this papers deals with the magnetic surveys acquired near \u201cMadonna della Valle\u201d and GPR and magnetic joint surveys carried out in \u201cMonastero\u201dsite. Most of magnetic maps carried out in \u201cMadonna della Valle\u201d site shown the absence of structured magnetic anomalies, despite of the presence of archaeological signs. Several hypothesis were given to explain this evidence. Joint interpretation performed in \u201cMonastero\u201d site shown more intense magnetic anomalies related with shallower reflections due to probably to buried pipes. Other reflections are related with magnetic anomalies compatible with archaeological targets, but some significant reflections do not correspond to any magnetic anomaly, indicating magnetic method could be \u201cblind\u201d respect the archaeological target. New field surveys including the electrical resistivity tomography could be carried out in order to overcome these acquisition and interpretation difficulties

Functionalized lactic acid macromonomers polycondensation

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