1,268 research outputs found

    La Necropoli a domus de janas di Ena Cuada-Villanova Monteleone (SS)

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    La necropoli di Ena Cuada consta di dieci ipogei situati nella parte N-O del territorio di Villanova Monteleone, non lontano dal confine comunale con Ittiri. Delle dieci sepolture conosciamo lo sviluppo planimetrico di nove; l'ultima, a causa del riempimento, è inaccessibile. Le domus de janas presentano generalmente planimetria atipica: solo tre di esse, la II, la III e la VIII, pare avessero, nel primo impianto, sviluppo a "T", variato, in seguito, dall'aggiunta di altri ambienti, creati, probabilmente, per sopraggiunte necessità

    Combining mitigation treatments against biases in personalized rankings: Use case on item popularity

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    Historical interactions leveraged by recommender systems are often non-uniformly distributed across items. Though they are of interest for consumers, certain items end up therefore being biasedly under-recommended. Existing treatments for mitigating these biases act at a single step of the pipeline (either pre-, in-, or post-processing), and it remains unanswered whether simultaneously introducing treatments throughout the pipeline leads to a better mitigation. In this paper, we analyze the impact of bias treatments along the steps of the pipeline under a use case on popularity bias. Experiments show that, with small losses in accuracy, the combination of treatments leads to better trade-offs than treatments applied separately. Our findings call for treatments rooting out bias at different steps simultaneously

    Robust reputation independence in ranking systems for multiple sensitive attributes

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    Ranking systems have an unprecedented influence on how and what information people access, and their impact on our society is being analyzed from different perspectives, such as users’ discrimination. A notable example is represented by reputation-based ranking systems, a class of systems that rely on users’ reputation to generate a non-personalized item-ranking, proved to be biased against certain demographic classes. To safeguard that a given sensitive user’s attribute does not systematically affect the reputation of that user, prior work has operationalized a reputation independence constraint on this class of systems. In this paper, we uncover that guaranteeing reputation independence for a single sensitive attribute is not enough. When mitigating biases based on one sensitive attribute (e.g., gender), the final ranking might still be biased against certain demographic groups formed based on another attribute (e.g., age). Hence, we propose a novel approach to introduce reputation independence for multiple sensitive attributes simultaneously. We then analyze the extent to which our approach impacts on discrimination and other important properties of the ranking system, such as its quality and robustness against attacks. Experiments on two real-world datasets show that our approach leads to less biased rankings with respect to multiple users’ sensitive attributes, without affecting the system’s quality and robustness

    ARE SUSCEPTIBILITY to INFECTIVE ENDOCARDITIS and EFFECTIVENESS of ANTIBIOTIC PROPHYLAXIS LINKED to FLUCTUATIONS of the IMMUNE SYSTEM? A NOVEL HYPOTHESIS

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    Introduction: An amendment incorporated into the 2007 AHA and 2009 ESC guidelines on infective endocarditis led to a substantial restriction in indications for the administration of antibiotic prophylaxis. This may have resulted in a subsequent steady increase in the number of cases of infective endocarditis worldwide. Methods: It has been hypothesised that susceptibility to infective endocarditis, together with effectiveness of antibiotic prophylaxis, may be linked to fluctuations of the immune system. Throughout a person’s lifetime, individual susceptibility to infective endocarditis may vary in an identical situation of risk. As a consequence, a personalised targeted approach should be adopted when prescribing antibiotic prophylaxis to prevent onset of endocarditis, taking into account a series of factors including age, comorbidities, cortisol levels, and ethnicity. Children affected by bicuspid aortic valve and injection drug users are amongst the newly-emerging higher risk populations. Conclusion: This up-to-dated narrative review summarizes all the available scientific evidence concerning the variable influence of the immune system on susceptibility to infective endocarditis

    Recency, Popularity, and Diversity of Explanations in Knowledge-based Recommendation

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    Modern knowledge-based recommender systems enable the end-to-end generation of textual explanations. These explanations are created from learnt paths between an already experience product and a recommended product in a knowledge graph, for a given user. However, none of the existing studies has investigated the extent to which properties of a single explanation (e.g., the recency of interaction with the already experience product) and of a group of explanations for a recommended list (e.g., the diversity of the explanation types) can influence the perceived explanation quality. In this paper, we summarize our previous work on conceptualizing three novel properties that model the quality of the explanations (linking interaction recency, shared entity popularity, and explanation type diversity) and proposing re-ranking approaches able to optimize for these properties. Experiments on two public data sets showed that our approaches can increase explanation quality according to the proposed properties, while preserving recommendation utility. Source code and data: https://github.com/giacoballoccu/explanation-quality-recsys

    XRecSys: A framework for path reasoning quality in explainable recommendation

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    There is increasing evidence that recommendations accompanied by explanations positively impact on businesses in terms of trust, guidance, and persuasion. This advance has been made possible by traditional models representing user–product interactions augmented with external knowledge modeled as knowledge graphs. However, these models produce textual explanations on top of reasoning paths extracted from the knowledge graph without considering relevant properties of the path entities. In this paper, we present XRecSys, a Python framework for the optimization of the reasoning path selection process according to properties deemed relevant by users (e.g., time relevance of the linking interaction or popularity of the entity linked to the explanation). Our framework leads to a higher reasoning path quality in terms of the considered properties and, consequently, textual explanations more relevant for the users

    Post Processing Recommender Systems with Knowledge Graphs for Recency, Popularity, and Diversity of Explanations

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    Existing explainable recommender systems have mainly modeled relationships between recommended and already experienced products, and shaped explanation types accordingly (e.g., movie "x"starred by actress "y"recommended to a user because that user watched other movies with "y"as an actress). However, none of these systems has investigated the extent to which properties of a single explanation (e.g., the recency of interaction with that actress) and of a group of explanations for a recommended list (e.g., the diversity of the explanation types) can influence the perceived explaination quality. In this paper, we conceptualized three novel properties that model the quality of the explanations (linking interaction recency, shared entity popularity, and explanation type diversity) and proposed re-ranking approaches able to optimize for these properties. Experiments on two public data sets showed that our approaches can increase explanation quality according to the proposed properties, fairly across demographic groups, while preserving recommendation utility. The source code and data are available at https: //github.com/giacoballoccu/explanation-quality-recsys

    I Monumenti e i dati morfologici e altimetrici

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    Con la presente analisi s'intende inquadrare i monumenti presenti nel territorio del comune di Sedilo, distinti per classe monumentale ed in fasce altimetriche. La 1. fascia (0-299 m s.l.m.) copre una superficie di kmq 58,8 e l'85,4% dell'intero territorio; la 2. fascia (300-599 m s.l.m.) ha una superficie di kmq 10 (14,5%;). L'analisi morfologica tiene conto delle unità di paesaggio individuate nel territorio comprendente settandue monumenti d'età prenuragica (domus de janas, dolmen, allés couvertes), una quarantina tra nuraghi a corridoi e a tholos, alcuni villaggi di capanne circolari, diverse tombe di giganti, cinque pozzi e una fonte sacra (Puntanarcu). Risalenti all'età preistorica sono invece delle strutture megalitiche nei siti di S'Isposu e Filigorri, mentre per l'età storica sono da annoverare sedici siti di età romana, tra cui un ponte, una strada e sei necropoli

    Growth of Listeria Monocytogenes in ready to eat salads at different storage temperatures and valuation of virulence genes expression

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    BACKGROUND: Vegetables are major components of a healthy and balanced diet. However, 25% of foodborne diseases are linked to the consumption of vegetables. STUDY DESIGN: The aim of this work was to assess the microbiological risks associated with consumption of ready to eat salads (RTE). METHODS: Microbiological challenge tests were carried out for the evaluation of the L. monocytogenes growth potential in RTE salads stored at different temperatures. RESULTS: The results indicate that L.monocytogenes was able to grow (δ ≥ 0.5) in all storage conditions considered at the end of shelf life. In order to evaluate the virulence role of L. monocytogenes, the temperature-dependent transcription of major virulence genes was also investigated by RT-PCR. CONCLUSIONS: The microbiological challenge test allowed us to confirm, as also demonstrated by other authors, that RTE salads are able to support the growth of L. monocytogenes strains (d δ≥ 0.5) stored under different temperatures
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