285 research outputs found

    Opening up innovation processes through contests in the food sector

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    Purpose: The purpose of this paper is to investigate how an adequate mix of technological, organisational and managerial tools might support Open Innovation (OI) processes achieved by contests in the food sector. Design/methodology/approach: The methodology of this paper is exploratory in nature. Data have been gathered about the 140 innovation contests launched by the best global food brands (2013 BusinessWeek/Interbrand Best Global Brands) over the last decade. Findings: The research highlights the main changes that have occurred over the last decade, showing that the choice of platform type for contest launches is often neglected or considered as an ancillary element. Indeed, it is a choice that embeds another set of technological, organisational and managerial tools that strongly influence the collaborative behaviour (and the participation itself) of partners throughout the innovation process. Research limitations/implications: Companies investigated in this paper consist exclusively of top brands in the sector. Future research should strive to obtain larger samples, develop a set of fine-grained hypotheses, and test them by using appropriate statistical techniques. Originality/value: This paper fills an inexplicable gap in academic literature due to the fact that food companies are those that mainly use contests in order to implement OI but they are scarcely researched regarding this issue

    Stability of Graph Convolutional Neural Networks through the lens of small perturbation analysis

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    In this work, we study the problem of stability of Graph Convolutional Neural Networks (GCNs) under random small perturbations in the underlying graph topology, i.e. under a limited number of insertions or deletions of edges. We derive a novel bound on the expected difference between the outputs of unperturbed and perturbed GCNs. The proposed bound explicitly depends on the magnitude of the perturbation of the eigenpairs of the Laplacian matrix, and the perturbation explicitly depends on which edges are inserted or deleted. Then, we provide a quantitative characterization of the effect of perturbing specific edges on the stability of the network. We leverage tools from small perturbation analysis to express the bounds in closed, albeit approximate, form, in order to enhance interpretability of the results, without the need to compute any perturbed shift operator. Finally, we numerically evaluate the effectiveness of the proposed bound.Comment: Accepted for publication in Proc. of 2024 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2024

    Theoretical and Numerical Hydromechanics Analysis of Self-Pitching Propellers

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    The development of design-oriented modelling techniques to predict Self-Pitching Propellers (SPP) hydrodynamic and dynamic behaviour is here addressed. Two hydrodynamics approaches are described and validated against literature data. Both Controllable-Pitch Propellers (CPP) and SPP test cases are considered. In addition, a general theoretical Reduced Order Model (ROM) for blade hydrodynamics unsteady loads is proposed to investigate blade equilibrium stability. Numerical results are shown in terms of performance, spindle moment and pitch setting equilibrium conditions. The proposed Blade Element Momentum Theory (BEMT) model shows to be well suited to capture SPP performance, spindle moment and blade equilibrium condition once a devoted tailoring process of model parameters is performed

    Cell Attention Networks

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    Since their introduction, graph attention networks achieved outstanding results in graph representation learning tasks. However, these networks consider only pairwise relationships among nodes and then they are not able to fully exploit higher-order interactions present in many real world data-sets. In this paper, we introduce Cell Attention Networks (CANs), a neural architecture operating on data defined over the vertices of a graph, representing the graph as the 1-skeleton of a cell complex introduced to capture higher order interactions. In particular, we exploit the lower and upper neighborhoods, as encoded in the cell complex, to design two independent masked self-attention mechanisms, thus generalizing the conventional graph attention strategy. The approach used in CANs is hierarchical and it incorporates the following steps: i) a lifting algorithm that learns {\it edge features} from {\it node features}; ii) a cell attention mechanism to find the optimal combination of edge features over both lower and upper neighbors; iii) a hierarchical {\it edge pooling} mechanism to extract a compact meaningful set of features. The experimental results show that CAN is a low complexity strategy that compares favorably with state of the art results on graph-based learning tasks.Comment: Preprint, under revie

    Generalized Simplicial Attention Neural Networks

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    The aim of this work is to introduce Generalized Simplicial Attention Neural Networks (GSANs), i.e., novel neural architectures designed to process data defined on simplicial complexes using masked self-attentional layers. Hinging on topological signal processing principles, we devise a series of self-attention schemes capable of processing data components defined at different simplicial orders, such as nodes, edges, triangles, and beyond. These schemes learn how to weight the neighborhoods of the given topological domain in a task-oriented fashion, leveraging the interplay among simplices of different orders through the Dirac operator and its Dirac decomposition. We also theoretically establish that GSANs are permutation equivariant and simplicial-aware. Finally, we illustrate how our approach compares favorably with other methods when applied to several (inductive and transductive) tasks such as trajectory prediction, missing data imputation, graph classification, and simplex prediction.Comment: arXiv admin note: text overlap with arXiv:2203.0748

    Geochemistry, stable isotopes and statistic tools to estimate threshold and source of nitrate in groundwater (Sardinia, Italy)

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    In the European Union, nitrate vulnerable zone (NVZ) should be designed for the mitigation of nitrate (NO3−) contamination caused by agricultural practices. Before establishing new NVZ, the sources of NO3− must be recognized. A geochemical and multiple stable isotopes approach (hydrogen, oxygen, nitrogen, sulfur and boron) and statistical tools were applied to define the geochemical characteristics of groundwater (60 samples), calculate the local NO3− threshold and assess potential sources of NO3− contamination in two study areas (hereafter Northern and Southern), located in a Mediterranean environment (Sardinia, Italy). Results of the integrated approach applied to two case study, permits to highlight the strengths of integrating geochemical and statistical methods to provide nitrate source identification as a reference by decision makers to remediate and mitigate nitrate contamination in groundwater. Hydrogeochemical features in the two study areas were similar: near neutral to slightly alkaline pH, electrical conductivity in the range of 0.3 to 3.9 mS/cm, and chemical composition ranging from Ca-HCO3− at low salinity to Na-Cl− at high salinity. Concentrations of NO3− in groundwater were in the range of 1 to 165 mg/L, whereas the nitrogen reduced species were negligible, except few samples having NH4+ up to 2 mg/L. Threshold values in the studied groundwater samples were between 4.3 and 6.6 mg/L NO3−, which was in agreement with previous estimates in Sardinian groundwater. Values of δ34S and δ18OSO4 of SO42− in groundwater samples indicated different sources of SO42−. Sulfur isotopic features attributed to marine SO42− were consistent with groundwater circulation in marine-derived sediments. Other source of SO42− were recognize due to the oxidation of sulfide minerals, to fertilizers, manure, sewage fields, and SO42− derived from a mix of different sources. Values of δ15N and δ18ONO3 of NO3− in groundwater samples indicated different biogeochemical processes and NO3− sources. Nitrification and volatilization processes might have occurred at very few sites, and denitrification was likely to occur at specific sites. Mixing among various NO3− sources in different proportions might account for the observed NO3− concentrations and the nitrogen isotopic compositions. The SIAR modeling results showed a prevalent NO3− source from sewage/manure. The δ11B signatures in groundwater indicated the manure to be the predominant NO3− source, whereas NO3− from sewage was recognized at few sites. Geographic areas showing either a predominant process or a defined NO3− source where not recognize in the studied groundwater. Results indicate widespread contamination of NO3− in the cultivated plain of both areas. Point sources of contamination, due to agricultural practices and/or inadequate management of livestock and urban wastes, were likely to occur at specific sites

    Silica-based mesoporous materials as drug delivery system for methotrexate release.

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    Antineoplastic methotrexate has been loaded through different soaking procedures on silica-based mesoporous materials and, successively, released mimicking an oral administration. The materials were prepared using a self-assembly mechanism in the presence of cationic surfactants with alkyl chain of 16, 12, and 10 carbon atoms in the synthesis mixture to obtain different pore diameter in the porous structure. Mesoporous materials were prepared as pure silica sample and in the presence of Al(OH)(3) in the synthesis mixture. Only alumina-silica samples were able to load methotrexate. The amounts of drug loaded and the in vitro release kinetics are a function of the pore size of the materials

    Exploring the role of e-waste management solutions and message framing in influencing consumer behaviours : the crowdfunding context

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    Electronics waste (e-waste) is the fastest growing category of hazardous solid waste in the world. While the generation of e-waste has recently attracted the attention of a number of researchers, currently, there is little awareness on its management, monitoring and control among the consumers of crowdfunding platforms. This is surprising because the supporters (backers) of crowdfunding are usually considered as disruptive innovators by other stakeholders. In this light, this research explores the role of e-waste management solutions and the formulation of “message framing” in influencing consumer behaviours in crowdfunding contexts. To do this, this study involves an in-depth investigation of fund-raising campaigns focused on e waste, that were promoted between 2009 and 2020, through Kickstarter’s reward-based crowdfunding platform. The results show that environmentally sustainable projects focused on waste reduction and pollution prevention are generating increased funds and triggering the interest of a number of crowd investors who are willing to finance such laudable initiatives. At the same time, the findings suggest that the fundraisers elaborate framing messages on environmental protection and on the preservation of the natural eco-systems can increase the likelihood of the success of their crowdfunding projects. This contribution contributes to both environmental management and to the crowdfunding literature. In conclusion, it offers practical implications for sustainable entrepreneurs who may resort to crowdfunding platforms to raise finance to decrease the accumulation of e-waste from the planet, as well as for other stakeholders including governments, policymakers, and public agencies.peer-reviewe

    HSP 27 aspossible prognostic factor in patients with oral squamous cell carcinoma.

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    Summary. HSP27 belongs to the Heat shock protein (HSP) family, which plays essential functions in cells under physiological conditions and prevents stressinduced cellular damage. The aim of this study was to investigate the biological role of HSP27 in oral tumorigenesis. Materials and methods: Seventy-nine cases of oral squamous cell carcinoma and 10 cases of normal mucosa were analysed for HSP27 expression by immunohistochemistry. Moreover, the western blot analysis was performed on two cases of normal mucosa and five cases of OSCC. Results: Normal oral mucosa showed a suprabasal expression of HSP27. Twenty-four cases of SCC (30.7%) showed a diffuse staining for HSP27, and 48 cases (60.3%) showed instead a decrease in staining, which was diffuse, homogeneous, or with alternation of positive and negative areas in a single tumor (“mosaic” pattern). Only 7 cases of OSCC (7.5%) were completely negative for HSP27. Frequency of lymph node metastases was higher in HSP27-negative tumours (3/7, 42.8%) than in HSP-reduced (16/48, 33.3%) or positive ones (5/26, 19.2%). Regard staging, stages I and II had a higher score than stages III and IV (stage I > stage II > stage III > stage IV). There was also a statistically significant correlation between HSP27 expression and grade: HSP27 expression was reduced in poorly differentiated tumours (P < 0.05). When analysed for prognostic significance, patients with negative/reduced HSP27 expression had poorer survival rates than the group with positive HSP27 expression (P < 0.05). The statistical analysis of these findings showed no significant correlation between HSP27 expression, sex, and tumour size. Conclusion: Cases with reduced expression were more aggressive and poorly differentiated. These data suggest that HSP27 expression may be useful in order to identify cases of oral squamous cell carcinoma with more aggressive and invasive phenotype providing novel diagnostic and prognostic information on individual patient survival with oral cancers

    Is expression of p120ctn in oral squamous cell carcinomas a prognostic factor?

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    Objectives p120ctn is a component of the catenin family. To date, there have only been two studies examining expression levels of p120ctn in oral squamous cell carcinoma (OSCC). Materials and methods Paraffined specimens of 113 OSCCs and 12 of normal mucosa were examined by immunohistochemistry. Frozen samples of 20 OSCCs and 5 of normal mucosa were examined by Western blot (WB). Results were correlated with clinicopathological parameters. Five cell lines were examined by immunofluorescence, immunocytochemistry, and WB to show immunoreactivity and cellular localization of p120ctn. Results Altered p120ctn expression was observed in 109/113 cases of OSCC. Heterogenous cytoplasmic/nuclear expression was associated with loss of membranous distribution (88/113 cases). Complete loss of expression was noted in 21/113 cases. Increased cytoplasmic expression was evident in all positive cases, without significant correlation among p120ctn staining/pattern and grading/stage. Reduction/absence of p120ctn expression was related to poor prognosis ( P Conclusion p120ctn delocalization/loss of expression could be an independent prognostic marker in OSCC
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