A replica free evaluation of the neuronal population information with mixed continuous and discrete stimuli: from the linear to the asymptotic regime

Recent studies have explored theoretically the ability of populations of neurons to carry information about a set of stimuli, both in the case of purely discrete or purely continuous stimuli, and in the case of multidimensional continuous angular and discrete correlates, in presence of additional quenched disorder in the distribution. An analytical expression for the mutual information has been obtained in the limit of large noise by means of the replica trick. Here we show that the same results can actually be obtained in most cases without the use of replicas, by means of a much simpler expansion of the logarithm. Fitting the theoretical model to real neuronal data, we show that the introduction of correlations in the quenched disorder improves the fit, suggesting a possible role of signal correlations-actually detected in real data- in a redundant code. We show that even in the more difficult analysis of the asymptotic regime, an explicit expression for the mutual information can be obtained without resorting to the replica trick despite the presence of quenched disorder, both with a gaussian and with a more realistic thresholded-gaussian model. When the stimuli are mixed continuous and discrete, we find that with both models the information seem to grow logarithmically to infinity with the number of neurons and with the inverse of the noise, even though the exact general dependence cannot be derived explicitly for the thresholded gaussian model. In the large noise limit lower values of information were obtained with the thresholded-gaussian model, for a fixed value of the noise and of the population size. On the contrary, in the asymptotic regime, with very low values of the noise, a lower information value is obtained with the gaussian model.Comment: 34 pages, 5 figure

Does fairness matter? Consumers' perception of fairness in the agro-food chain

IntroductionDefining 'fairness' in the agro-food sector is a challenging task. There is no single definition of fairness and the literature does not provide a complete conceptualization from the consumer's point of view. The current research seeks to explore the consumers' interest in fairness and ethics in the agro-food chain by exploring (i) a comprehensive theoretical framework to conceptualize fairness from a consumer perspective, and (ii) the consumers' perceived importance of different food attributes as fairness-related aspects. MethodLiterature review and focus groups allowed for the creation of the final survey to be submitted to consumers. 529 valid responses from a predominantly Italian female sample were collected. Data were elaborated with Exploratory Factor Analysis and ANOVA test. ResultsThe research identified five dimensions of fairness: Fair price, environment, networking, short chain, and working condition. Also, it emerged that age influences consumers' perceived importance of products with fair attributes. DiscussionThis research contributes to the development of a fairer and more sustainable food system by identifying perceptions of agro-food chain fairness and establishing a link with food shopping intentions. The research provides companies with suggestions on how to expand sales by reaching a greater number of consumers

Chocolate consumption and purchasing behaviour review: Research issues and insights for future research

Chocolate is consumed all over the world. Since its origin, it has undergone many transformations to meet changing market demand. A better understanding of consumer behaviour is a key objective of any business, and so it is for chocolate businesses. In order to fulfil this aim, the current study presents a systematic literature review of consumers' consumption and purchasing behaviour towards cocoa and chocolate. Two databases have been used to collect the literature: Scopus andWeb of Science. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram was used to identify the articles through the process of data screening and extractions. A total of sixty-four scientific articles have been selected. Research topics, methodological approach and data collection method were identified for each article selected. Then, the identified topics were grouped into four categories in order to obtain a model of major determinants in chocolate consumption: personal preferences, product attributes, socio-demographic factors and economic attributes. Results show that there is a strong focus on Fair Trade in chocolate. Moreover, the current literature review supports the fact that the price and promotion are under-investigated issues. This research represents a valuable tool, especially from a marketing point of view, by creating new channels and new sales opportunities for chocolate products

Sheet metal forming optimization methodology for servo press process control improvement

In sheet metal forming manufacturing operations the use of servo presses is gaining more interest due to the opportunity to improve process performance (quality, productivity, cost reduction, etc.). It is not yet clear how to proceed in the engineering process when this type of operating machine is used to achieve the maximum possible potential of this technology. Recently, several press builders have developed gap‐ and straight‐sided metal forming presses adopting the mechanical servo‐drive technology. The mechanical servo‐drive press offers the flexibility of a hydraulic press with the speed, accuracy and reliability of a mechanical press. Servo drive presses give the opportunity to improve the productivity of process conditions and improve the quality of stamped parts. Forming simulation and numerical optimization can be useful tools to define beforehand the optimal process parameter set‐up in terms of servo press downward curve properties. This is done by carrying out a sensitivity analysis of the forming parameters having influence on said curve. The authors have developed a numerical methodology able to analyze the influence factors, for comparison with the degrees of freedom made available by the usage of a servo press, in terms of stroke profile management, to obtain an optimized process parameters combination

Optimization of Machining Fixture for Aeronautical Thin-walled Components☆

Abstract The aim of this work has been the optimization of the fixtures performance used in thin-walled workpiece machining depending on the local rigidity characteristics of the component to be machined. An extensive topology optimization activity has been performed both on fixture-workpiece systems modelled with shell elements and on fixture-workpiece systems modelled with solid elements, varying the topology design variables and/or optimization constraints for each optimization problem, in order to provide a new design of fixture. Finally, a new blended Solid-Lattice design of the fixture, starting by the design topologically optimized, has been created. In this way, it has been possible to identify void regions in the design space, where the material can be removed, regions where solid material is needed, and regions where lattice structure is required. This has allowed to generate the optimal hybrid or blended solid-lattice design based on desired functionality of the part having as natural consequence the definition of a new method for fixtures design

Numerical Simulation of Machining Nickel-Based Alloy

none3The phenomenological models for material flow stress and fracture, typically used in the Finite Element simulations of machining Nickel-based alloys, are often deemed to represent only certain metallurgical material states. In contrast, these models are not suitable to describe the constitutive behavior of the workpiece for different metallurgical states (i.e., annealed, aged, etc.) and, consequently, different hardness values. Since the description of the material behavior requires correct formulation of the constitutive law, new flow stress models which include also the hardness effect should be developed and used, for computer simulation of machining Nickel-based alloys. This paper describes the development of a hardness-based flow stress and fracture models for machining Inconel 718 alloy which can be applied for a wide range of work material hardness. These models have been implemented in a non-isothermal viscoplastic numerical model to simulate the influence of work material hardness on the chip formation process. The predicted results are being validated with experimental results properly carried out for this research. They are found to satisfactory predict the cutting forces, the temperature and the chip morphology from continuous to segmented chip as the hardness values changeopenDel Prete A.; Filice L.; Umbrello D.;DEL PRETE, Antonio; Filice, L.; Umbrello, D

Functional needs, emotions, and perceptions of coffee consumers and non-consumers

Coffee is one of the most consumed beverages worldwide. Over the last decades coffee has become a specialty product. Drinking a coffee beverage entails several mixed factors, such as pleasure, experience, lifestyle, and social status. It can also provide an emotional pick-up, both mentally and physically. Only a few studies have explored the motives and emotions of coffee consumption and not consumption. There is limited understanding of consumers' emotional approach towards coffee, and what influences a positive and negative inclination towards coffee consumption. This research fills the current research gaps by addressing three main questions: (i) What are the emotions and habits of coffee consumption? (ii) What are the motives of coffee consumption and non-consumption? and (iii) How relevant is the coffee health impact perception of consuming or not consuming coffee? The research activities include 467 face-to-face interviews with consumers. Interviews are performed in two different countries, Italy and Portugal. Data elaboration includes a principal component analysis carried out to identify latent factors on motives and emotions of consumption in both national groups, and to explore the relationship between the main emotions and consumers' habits and socio-economic characteristics. Results support that consumers have positive emotions from coffee consumption. Perceived emotions are energy, satisfaction, and pleasure. Non-consumption is mainly driven by taste and fear of coffee's health impacts. There are limited differences in the countries analysed. Socio-economic characteristics limitedly influence perceived emotions and consumption motives. To conclude, consumers are increasingly interested in new coffee products. Understanding the functional and emotional factors of coffee consumption contributes to supporting new coffee product development and commercialisation