463 research outputs found

    Prioritized Repairing and Consistent Query Answering in Relational Databases

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    A consistent query answer in an inconsistent database is an answer obtained in every (minimal) repair. The repairs are obtained by resolving all conflicts in all possible ways. Often, however, the user is able to provide a preference on how conflicts should be resolved. We investigate here the framework of preferred consistent query answers, in which user preferences are used to narrow down the set of repairs to a set of preferred repairs. We axiomatize desirable properties of preferred repairs. We present three different families of preferred repairs and study their mutual relationships. Finally, we investigate the complexity of preferred repairing and computing preferred consistent query answers.Comment: Accepted to the special SUM'08 issue of AMA

    Characterizing and computing causes for query answers in databases from database repairs and repair programs

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    A correspondence between database tuples as causes for query answers in databases and tuple-based repairs of inconsistent databases with respect to denial constraints has already been established. In this work, answer-set programs that specify repairs of databases are used as a basis for solving computational and reasoning problems about causes. Here, causes are also introduced at the attribute level by appealing to a both null-based and attribute-based repair semantics. The corresponding repair programs are presented, and they are used as a basis for computation and reasoning about attribute-level causes

    Is post orthognathic maxillary sinusitis related to sino-nasal anatomical alterations?

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    Le Fort I osteotomies have been used for more than five decades, but their impact on nasal and paranasal cavities physiology, has not been studied deeply. In this paper we want to analyse the possible correlation between post-orthognathic findings and prevalence of sinusitis which require surgical treatment. A retrospective cohort study was designed in 2017; the study was designed and carried out in the Verona University maxillo-facial department, a referral centre for orthognathic surgery. The study population is made of 64 patients that underwent orthognathic surgery (To treat class II or III malocclusion) between 2010 and 2015. Inclusion criteria were the availability of a Cone Beam Computed Tomography (CBCT) before surgery and one between 12 and 24 months after orthognathic surgery. Exclusion criteria were smoking habit and previous orthognathic procedures. During follow-up time prevalence of sinusitis was 18.5% and some patients required a secondary surgery to treat sinusitis. Surgery induced anatomic alterations were frequent in patients with sinusitis, sings and symptoms of sinusitis show positive correlation with anatomic alterations

    Information sharing agents in a peer data exchange system

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    We present a semantics and answer set programs for relational peer data exchange systems. When a peer answers a query, it exchanges data with other peers in order to supplement or modify its own data source. The data exchange relationships between peers are specified by logical sentences called data exchange constraints and trust relationships, which together determine how data is moved around (in order to keep them satisfied). This process determines virtual, alternative instances for a peer that can be specified as the models of an answer set program. The peer consistent answers to a query that are returned by a peer are those that are invariant under all these instances. The logic program can be used to compute peer consistent answers

    The contribution of CXCL12-expressing radial glia cells to neuro-vascular patterning during human cerebral cortex development

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    This study was conducted on human developing brain by laser confocal and transmission electron microscopy (TEM) to make a detailed analysis of important features of blood-brain barrier (BBB) microvessels and possible control mechanisms of vessel growth and differentiation during cerebral cortex vascularization. The BBB status of cortex microvessels was examined at a defined stage of cortex development, at the end of neuroblast waves of migration, and before cortex lamination, with BBB-endothelial cell markers, namely tight junction (TJ) proteins (occludin and claudin-5) and influx and efflux transporters (Glut-1 and P-glycoprotein), the latter supporting evidence for functional effectiveness of the fetal BBB. According to the well-known roles of astroglia cells on microvessel growth and differentiation, the early composition of astroglia/endothelial cell relationships was analyzed by detecting the appropriate astroglia, endothelial, and pericyte markers. GFAP, chemokine CXCL12, and connexin 43 (Cx43) were utilized as markers of radial glia cells, CD105 (endoglin) as a marker of angiogenically activated endothelial cells (ECs), and proteoglycan NG2 as a marker of immature pericytes. Immunolabeling for CXCL12 showed the highest level of the ligand in radial glial (RG) fibers in contact with the growing cortex microvessels. These specialized contacts, recognizable on both perforating radial vessels and growing collaterals, appeared as CXCL12-reactive en passant, symmetrical and asymmetrical, vessel-specific RG fiber swellings. At the highest confocal resolution, these RG varicosities showed a CXCL12-reactive dot-like content whose microvesicular nature was confirmed by ultrastructural observations. A further analysis of RG varicosities reveals colocalization of CXCL12 with Cx43, which is possibly implicated in vessel-specific chemokine signaling

    ERBlox: Combining Matching Dependencies with Machine Learning for Entity Resolution

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    Entity resolution (ER), an important and common data cleaning problem, is about detecting data duplicate representations for the same external entities, and merging them into single representations. Relatively recently, declarative rules called matching dependencies (MDs) have been proposed for specifying similarity conditions under which attribute values in database records are merged. In this work we show the process and the benefits of integrating three components of ER: (a) Classifiers for duplicate/non-duplicate record pairs built using machine learning (ML) techniques, (b) MDs for supporting both the blocking phase of ML and the merge itself; and (c) The use of the declarative language LogiQL -an extended form of Datalog supported by the LogicBlox platform- for data processing, and the specification and enforcement of MDs.Comment: To appear in Proc. SUM, 201

    Aneurysmal bone cyst of the nasal bone: case report

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    The aneurysmal bone cyst (ABC) is a solitary, expansile, non-neoplastic bone lesion, described as a distinct clinicopathological entity by Jaffe and Lichtenstein. We report a case of an ABC arising from the nasal bone in a adult male patient treated with complete surgical excision
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