Cortical free association dynamics: distinct phases of a latching network

A Potts associative memory network has been proposed as a simplified model of macroscopic cortical dynamics, in which each Potts unit stands for a patch of cortex, which can be activated in one of S local attractor states. The internal neuronal dynamics of the patch is not described by the model, rather it is subsumed into an effective description in terms of graded Potts units, with adaptation effects both specific to each attractor state and generic to the patch. If each unit, or patch, receives effective (tensor) connections from C other units, the network has been shown to be able to store a large number p of global patterns, or network attractors, each with a fraction a of the units active, where the critical load p_c scales roughly like p_c ~ (C S^2)/(a ln(1/a)) (if the patterns are randomly correlated). Interestingly, after retrieving an externally cued attractor, the network can continue jumping, or latching, from attractor to attractor, driven by adaptation effects. The occurrence and duration of latching dynamics is found through simulations to depend critically on the strength of local attractor states, expressed in the Potts model by a parameter w. Here we describe with simulations and then analytically the boundaries between distinct phases of no latching, of transient and sustained latching, deriving a phase diagram in the plane w-T, where T parametrizes thermal noise effects. Implications for real cortical dynamics are briefly reviewed in the conclusions

Thermomechanical properties of amorphous metallic tungsten-oxygen and tungsten-oxide coatings

In this work, we investigate the correlation between morphology, composition, and the mechanical properties of metallic amorphous tungsten-oxygen and amorphous tungsten-oxide films deposited by Pulsed Laser Deposition. This correlation is investigated by the combined use of Brillouin Spectroscopy and the substrate curvature method. The stiffness of the films is strongly affected by both the oxygen content and the mass density. The elastic moduli show a decreasing trend as the mass density decreases and the oxygen-tungsten ratio increases. A plateaux region is detected in correspondence of the transition between metallic and oxide films. The compressive residual stresses, moderate stiffness and high local ductility that characterize compact amorphous tungsten-oxide films make them promising for applications involving thermal or mechanical loads. The coefficient of thermal expansion is quite high (i.e. 8.9 $\cdot$ 10$^{-6}$ K$^{-1}$), being strictly correlated to the amorphous structure and stoichiometry of the films. Under thermal treatments they show a quite low relaxation temperature (i.e. 450 K). They crystallize into the $\gamma$ monoclinic phase of WO$_3$ starting from 670 K, inducing an increase by about 70\% of material stiffness.Comment: The research leading to these results has also received funding from the European Research Council Consolidator Grant ENSURE (ERC-2014-CoG No. 647554). The views and opinions expressed herein do not necessarily reflect those of the European Commissio

Drying kinetics and physico-chemical quality of mango slices

Mango (Mangifera indica L.) is an important tropical fruit consumed worldwide and grown in Italy only in Sicily, where the areas of the Tyrrhenian coast have proved to be suitable to produce valuable fruits. Mango fruit has a pleasant aroma and taste, which are important qualities for consumer’s sensorial acceptance. However, they are highly perishable, prone to progressive undesired changes if stored untreated, resulting in around 25% postharvest losses, which is further increased during storage and transportation. An alternative for reducing the above-mentioned undesired changes is the dehydration of the cut fruit, which reduce the fruit water activity, thereby avoiding the deteriorative process and extending the shelf-life. This study investigates the effect of dehydration at different temperatures (50, 60 and 70°C) on drying kinetics and volatile compounds of two cultivars (Keitt and Osteen) of mango fruits cultivated in Sicily. Significant losses of volatile constituents of fresh mango occurred at higher temperature, especially for the Osteen cultivar. A diffusion model including the effect of shrinkage is also proposed, which may be used to describe drying behaviour of fruits and to define the optimal drying conditions.. Experimental data of the moisture ratio during drying were well predicted by the model

accuracy of cultural heritage 3d models by rpas and terrestrial photogrammetry

The combined use of high-resolution digital images taken from ground as well as from RPAS (Remotely Piloted Aircraft Systems) have significantly increased the potential of close range digital photogrammetry applications in Cultural Heritage surveying and modeling. It is in fact possible, thanks to SfM (Structure from Motion), to simultaneously process great numbers of aerial and terrestrial images for the production of a dense point cloud of an object. In order to analyze the accuracy of results, we started numerous tests based on the comparison between 3D digital models of a monumental complex realized by the integration of aerial and terrestrial photogrammetry and an accurate TLS (Terrestrial Laser Scanner) reference model of the same object. A lot of digital images of a renaissance castle, assumed as test site, have been taken both by ground level and by RPAS at different distances and flight altitudes and with different flight patterns. As first step of the experimentation, the images were previously processed with Agisoft PhotoScan, one of the most popular photogrammetric software. The comparison between the photogrammetric DSM of the monument and a TLS reference one was carried out by evaluating the average deviation between the points belonging to the two entities, both globally and locally, on individual façades and architectural elements (sections and particular). In this paper the results of the first test are presented. A good agreement between photogrammetric and TLS digital models of the castle is pointed out

Analisi cluster delle caratteristiche socio-economiche dei comuni dell'Emilia-Romagna: un confronto tra comuni dentro e fuori dal cratere del sisma

The socio-economic features of the area hit by the 2012 earthquake in Emilia-Romagna (Italy) represents a first step in building a more comprehensive framework, which could help in better interpreting earthquake effects in both short and medium period. Actually, this analysis falls under that broader field of research, which is aimed at providing counterfactual evaluations of both natural disasters’ impacts and the adoption of public policies to support reconstruction. This paper moves from the idea that those municipalities, which lie close to the epicentre of 2012 Emilia-Romagna earthquake, are not particularly homogenous in terms of socio-economic features. Analysing those major differences is a key element in order to assess the way human activities and other specific economic features at municipality level may either increase or limit the effects of an earthquake. Firstly, this paper tackles the problem of properly identifying the boundaries of the area directly hit by the 2012 earthquake. Indeed, different acts have provided different definitions of those boundaries. Eventually, a cluster analysis has been performed covering all municipalities in Emilia-Romagna, according to a set of demographic and economic variables, available at municipality level. This analysis highlights the existence of different typologies of municipalities, even in the area hit by the earthquake. In particular, these results are of particular interest, allowing further assessments on the effects of the earthquake. Actually, according to cluster analysis results, specific counterfactual examples (not hit by the earthquake) will be identified

Documentare e comunicare l'attività di trasferimento tecnologico. Analisi testuale della comunicazione dei poli di innovazione

There is an increasing attention on the needs to support SMEs in enhancing their innovation opportunities and capabilities. Through a policy measure to foster the regional innovation system, 12 innovation poles were active in Tuscany in the period 2011-2014 to provide to their members (affiliation is needed) a range of knowledge-intensive services such as knowledge and technology mapping, R&D partnership formation, technical assistance in R&D projects, technology transfer. Each pole was created as a consortium of organizations operating as public or private research centres and service centres (universities, innovation centres or technology transfer centres and firms). In this paper we adopt a statistical analysis of textual content produced by the innovation poles to identify distinctive or common elements in the various texts they produced in three years of activity and to draw some assessment of their communication on their activities. Documents under analysis are of different types: designed as written texts (on Smart Specialization Strategy and monitoring the activities of the poles), transcripts of spoken language (the recordings of interviews); web communication. Through and automatic analysis we propose a systematic comparison of all these documents that would not be possible through direct reading of texts: on the whole it is over 56,000 graphic forms, for a total of over two million occurrences. To compare both the intra diversity across the same type of document and across the different types of documents, first we analyse each of the four body separately, in order to identify the specific content and the four languages used by the poles of innovation: "report", texts structured in the format of the monitoring; "design", the documents on smart specialization strategy; "reflection and analysis", in the transcription of interviews; and "communication", that characterizes the web sites. For this analysis, each document is associated with one or more categories (such as, for example, pole' band category, date of the document) that allow us to group or isolate relevant content in different contexts. In this work we first introduce the set of processing of texts aimed at the selection of graphic forms on which we focus our analysis. Then, we present for each corpus the description of the analysed documents, the results of calculations performed for the treatment of the text and the analysis of the main components that explain the variability of language within each corpus. These analyses (represented by the factorial of two main components) interpret the selection of graphic forms being analysed with respect to categorical variables, defined for each document in each of the corpora. The analysis concludes with some ideas for the modelling of regional system of innovation clusters in Tuscany

Documentare e comunicare l'attività di trasferimento tecnologico. Analisi testuale della comunicazione dei poli di innovazione

There is an increasing attention on the needs to support SMEs in enhancing their innovation op-portunities and capabilities. Through a policy measure to foster the regional innovation system, 12 innovation poles were active in Tuscany in the period 2011-2014 to provide to their members (af-filiation is needed) a range of knowledge-intensive services such as knowledge and technology mapping, R&D partnership formation, technical assistance in R&D projects, technology transfer. Each pole was created as a consortium of organizations operating as public or private research cen-tres and service centres (universities, innovation centres or technology transfer centres and firms). In this paper we adopt a statistical analysis of textual content produced by the innovation poles to identify distinctive or common elements in the various texts they produced in three years of activi-ty and to draw some assessment of their communication on their activities. Documents under analysis are of different types: designed as written texts (on Smart Specializa-tion Strategy and monitoring the activities of the poles), transcripts of spoken language (the re-cordings of interviews); web communication. Through and automatic analysis we propose a sys-tematic comparison of all these documents that would not be possible through direct reading of texts: on the whole it is over 56,000 graphic forms, for a total of over two million occurrences. To compare both the intra diversity across the same type of document and across the different types of documents, first we analyse each of the four body separately, in order to identify the specific con-tent and the four languages used by the poles of innovation: "report", texts structured in the format of the monitoring; "design", the documents on smart specialization strategy; "reflection and analy-sis", in the transcription of interviews; and "communication", that characterizes the web sites. For this analysis, each document is associated with one or more categories (such as, for example, pole' band category, date of the document) that allow us to group or isolate relevant content in different contexts. In this work we first introduce the set of processing of texts aimed at the selection of graphic forms on which we focus our analysis. Then, we present for each corpus the description of the analysed documents, the results of calculations performed for the treatment of the text and the analysis of the main components that explain the variability of language within each corpus. These analyses (represented by the factorial of two main components) interpret the selection of graphic forms be-ing analysed with respect to categorical variables, defined for each document in each of the corpo-ra. The analysis concludes with some ideas for the modelling of regional system of innovation clusters in Tuscany