475 research outputs found

    A comparative analysis of rule-based, model-agnostic methods for explainable artificial intelligence

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    The ultimate goal of Explainable Artificial Intelligence is to build models that possess both high accuracy and degree of explainability. Understanding the inferences of such models can be seen as a process that discloses the relationships between their input and output. These relationships can be represented as a set of inference rules which are usually not explicit within a model. Scholars have proposed several methods for extracting rules from data-driven machine-learned models. However, limited work exists on their comparison. This study proposes a novel comparative approach to evaluate and compare the rulesets produced by four post-hoc rule extractors by employing six quantitative metrics. Findings demonstrate that these metrics can actually help identify superior methods over the others thus are capable of successfully modelling distinctively aspects of explainability

    The laminA/NF-Y protein complex reveals an unknown transcriptional mechanism on cell proliferation

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    Lamin A is a component of the nuclear matrix that also controls proliferation by largely unknown mechanisms. NF-Y is a ubiquitous protein involved in cell proliferation composed of three subunits (-YA -YB -YC) all required for the DNA binding and transactivation activity. To get clues on new NF-Y partner(s) we performed a mass spectrometry screening of proteins that co-precipitate with the regulatory subunit of the complex, NF-YA. By this screening we identified lamin A as a novel putative NF-Y interactor. Co-immunoprecipitation experiments and confocal analysis confirmed the interaction between the two endogenous proteins. Interestingly, this association occurs on euchromatin regions, too. ChIP experiments demonstrate lamin A enrichment in several promoter regions of cell cycle related genes in a NF-Y dependent manner. Gain and loss of function experiments reveal that lamin A counteracts NF-Y transcriptional activity. Taking advantage of a recently generated transgenic reporter mouse, called MITO-Luc, in which an NF-Y–dependent promoter controls luciferase expression, we demonstrate that lamin A counteracts NF-Y transcriptional activity not only in culture cells but also in living animals. Altogether, our data demonstrate the occurrence of lamin A/NF-Y interaction and suggest a possible role of this protein complex in regulation of NF-Y function in cell proliferatio

    Corrections to the Bethe lattice solution of Anderson localization

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    We study numerically Anderson localization on lattices that are tree-like except for the presence of one loop of varying length LL. The resulting expressions allow us to compute corrections to the Bethe lattice solution on i) Random-Regular-Graph (RRG) of finite size NN and ii) euclidean lattices in finite dimension. In the first case we show that the 1/N1/N corrections to to the average values of observables such as the typical density of states and the inverse participation ratio have prefactors that diverge exponentially approaching the critical point, which explains the puzzling observation that the numerical simulations on finite RRGs deviate spectacularly from the expected asymptotic behavior. In the second case our results, combined with the MM-layer expansion, predict that corrections destroy the exotic critical behavior of the Bethe lattice solution in any finite dimension, strengthening the suggestion that the upper critical dimension of Anderson localization is infinity. This approach opens the way to the computation of non-mean-field critical exponents by resumming the series of diverging diagrams through the same recipes of the field-theoretical perturbative expansion

    Autothermal biochar production and characterization at pilot scale

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    The present work reports on the results from the validation campaign of an autothermal pilot carbonization unit (CarbON) and on the characterization of the produced biochar and pyrolysis vapors. The proposed pilot plant leverages the simplicity and effectiveness of autothermal operations together with open top, downdraft design, to bring to the small scale the performance of larger installations. In autothermal operation, heat for the process is internally provided by combusting part of the feedstock and evolved volatiles inside the reactor, the so called “oxidative pyrolysis”. Please click on the file below for full content of the abstract

    Can MRI biomarkers predict triple-negative breast cancer?

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    The purpose of this study was to investigate MRI features of triple-negative breast cancer (TNBC) compared with non-TNBC, to predict histopathological results. In the study, 26 patients with TNBC and 24 with non-TNBC who underwent multiparametric MRI of the breast on a 3 T magnet over a 10-months period were retrospectively recruited. MR imaging sets were evaluated by two experienced breast radiologists in consensus and classified according to the 2013 American College of Radiology (ACR) BI-RADS lexicon. The comparison between the two groups was performed using the Chi-square test and followed by logistic regression analyses. We found that 92% of tumors presented as mass enhancements (p = 0.192). 41.7% of TNBC and 86.4% of non-TNBC had irregular shape (p = 0.005); 58.3% of TNBC showed circumscribed margins, compared to 9.1% of non-TNBC masses (p = 0.001); 75% of TNBC and 9.1% of non-TNBC showed rim enhancement (p < 0.001). Intralesional necrosis was significantly associated with TNBC (p = 0.016). Rim enhancement and intralesional necrosis risulted to be positive predictors at univariate analysis (OR = 29.86, and 8.10, respectively) and the multivariate analysis confirmed that rim enhancement is independently associated with TNBC (OR = 33.08). The mean ADC values were significantly higher for TNBC (p = 0.011). In conclusion, TNBC is associated with specific MRI features that can be possible predictors of pathological results, with a consequent prognostic value

    Coexistence of supersymmetric and supersymmetry-breaking states in spherical spin-glasses

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    The structure of states of the perturbed p-spin spherical spin-glass is analyzed. At low enough free energy metastable states have a supersymmetric structure, while at higher free energies the supersymmetry is broken. The transition between the supersymmetric and the supersymmetry-breaking phase is triggered by a change in the stability of states

    Aqueous phase reforming of lignin-rich hydrothermal liquefaction by-products: a study on catalyst deactivation

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    The water fraction derived from the hydrothermal liquefaction of a lignin-rich feedstock was subjected to aqueous phase reforming to produce hydrogen. Deactivation of the catalyst was observed, and it was ascribed to fouling phenomena caused by phenolic oligomers. Simple aromatics like guaiacol and phenol, as well as in-organics, were proved not to be the cause of the deactivation thanks to the use of a multi-component synthetic mixture. The influence of using activated carbon as a pretreatment was studied, leading to a strong improvement of the performance when it was carried out at high temperature. The extent of deactivation was assessed using aqueous phase reforming of glycolic acid as a model reaction test. The results were found to be correlated with the surface area of the catalyst. A thermal regeneration in inert conditions was evaluated as a mode of catalyst regeneration. While the textural properties were partially recovered, the performance of the catalyst only slightly improved. A spectroscopic analysis of the solids in the aqueous solution was carried out, highlighting the structural similarities between their nature and the lignin residue. The results obtained in this study helped to enlarge the knowledge on the aqueous phase reforming of real complex mixtures, looking at indicators of paramount importance for a possible industrial application such as the stability of the catalyst

    Lab-scale pyrolysis and hydrothermal carbonization of biomass digestate: Characterization of solid products

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    The aim of the present study is to investigate the production of biochar from anaerobic digestion (AD) digestate. Re-Cord selected digestate from real and representative (regarding the scale and the process technology) anaerobic digestion plant. Please click on the file below for full content of the abstract
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