60 research outputs found

    Irrevocable belief revision and epistemic entrenchment

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    In recent papers [10, 11] Krister Segerberg introduced Irrevocable Belief Revision, as closely related to AGM revision [2]. In this paper we present irrevocable belief revision in terms of an epistemic entrenchment relation.1info:eu-repo/semantics/publishedVersio

    An axiomatic characterization of ensconcement-based contraction

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    In this article, we propose an axiomatic characterization for ensconcement-based contraction functions, belief base functions proposed by Williams. We relate this function with other kinds of base contraction functions.info:eu-repo/semantics/publishedVersio

    Studies on brutal contraction and severe withdrawal

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    In this paper we present an axiomatic characterization for brutal contractions. Then we consider the particular case of the brutal contractions that are based on a bounded ensconcement and also the class of severe withdrawals which are based on bounded epis temic entrenchment relations that are defined by means of bounded ensconcements (using the procedure proposed by Mary-Anne Williams). We present axiomatic characterizations for each one of those classes of functions and investigate the interrelation among them.info:eu-repo/semantics/publishedVersio

    Decrement Operators in Belief Change

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    While research on iterated revision is predominant in the field of iterated belief change, the class of iterated contraction operators received more attention in recent years. In this article, we examine a non-prioritized generalisation of iterated contraction. In particular, the class of weak decrement operators is introduced, which are operators that by multiple steps achieve the same as a contraction. Inspired by Darwiche and Pearl's work on iterated revision the subclass of decrement operators is defined. For both, decrement and weak decrement operators, postulates are presented and for each of them a representation theorem in the framework of total preorders is given. Furthermore, we present two sub-types of decrement operators

    Chemotherapy followed by low dose radiotherapy in childhood Hodgkin's disease: retrospective analysis of results and prognostic factors

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    PURPOSE: To report the treatment results and prognostic factors of childhood patients with Hodgkin's disease treated with chemotherapy (CT) followed by low dose radiotherapy (RT). PATIENTS AND METHODS: This retrospective series analyzed 166 patients under 18 years old, treated from January 1985 to December 2003. Median age was 10 years (range 2–18). The male to female ratio was 2,3 : 1. Lymphonode enlargement was the most frequent clinical manifestation (68%), and the time of symptom duration was less than 6 months in 55% of the patients. In histological analysis Nodular Sclerosis was the most prevalent type (48%) followed by Mixed Celularity (34.6%). The staging group according Ann Arbor classification was: I (11.7%), II (36.4%), III (32.1%) and IV (19.8%). The standard treatment consisted of chemotherapy multiple drug combination according the period of treatment protocols vigent: ABVD in 39% (n-65) of the cases, by VEEP in 13 %(n-22), MOPP in 13 %(n-22), OPPA-13 %(n-22) and ABVD/OPPA in 22 %(n-33). Radiotherapy was device to all areas of initial presentation of disease. Dose less or equal than 21 Gy was used in 90.2% of patients with most part of them (90%) by involved field (IFRT) or mantle field. RESULTS: The OS and EFS in 10 years were 89% and 87%. Survival according to clinical stage as 94.7%, 91.3%, 82.3% and 71% for stages I to IV(p = 0,005). The OS was in 91.3% of patients who received RT and in 72.6% of patients who did not (p = 0,003). Multivariate analysis showed presence of B symptoms, no radiotherapy and advanced clinical stage to be associated with a worse prognosis. CONCLUSION: This data demonstrating the importance of RT consolidation with low dose and reduced volume, in all clinical stage of childhood HD, producing satisfactory ten years OS and EFS. As the disease is highly curable, any data of long term follow-up should be presented in order to better direct therapy, and to identify groups of patients who would not benefit from radiation treatment

    Parenthood in survivors of Hodgkin lymphoma: an EORTC-GELA general population case-control study.

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    Contains fulltext : 108966.pdf (publisher's version ) (Open Access)PURPOSE: We investigated the impact of Hodgkin lymphoma (HL) on parenthood, including factors influencing parenthood probability, by comparing long-term HL survivors with matched general population controls. PATIENTS AND METHODS: A Life Situation Questionnaire was sent to 3,604 survivors treated from 1964 to 2004 in successive clinical trials. Responders were matched with controls (1:3 or 4) for sex, country, education, and year of birth (10-year groups). Controls were given an artificial date of start of treatment equal to that of their matched case. The main end point was presence of biologic children after treatment, which was evaluated by using conditional logistic regression analysis. Logistic regression analysis was used to analyze factors influencing spontaneous post-treatment parenthood. RESULTS: In all, 1,654 French and Dutch survivors were matched with 6,414 controls. Median follow-up was 14 years (range, 5 to 44 years). After treatment, the odds ratio (OR) for having children was 0.77 (95% CI, 0.68 to 0.87; P < .001) for survivors compared with controls. Of 898 survivors who were childless before treatment, 46.7% achieved post-treatment parenthood compared with 49.3% of 3,196 childless controls (OR, 0.87; P = .08). Among 756 survivors with children before treatment, 12.4% became parents after HL treatment compared with 22.2% of 3,218 controls with children before treatment (OR, 0.49; P < .001). Treatment with alkylating agents, second-line therapy, and age older than 35 years at treatment appeared to reduce the chances of spontaneous post-treatment parenthood. CONCLUSION: Survivors of HL had slightly but significantly fewer children after treatment than matched general population controls. The difference concerned only survivors who had children before treatment and appears to have more personal than biologic reasons. The chance of successful post-treatment parenthood was 76%

    Credibility: limited functions for belief bases

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    Construction of system of spheres-based transitively relational partial meet multiple contractions: An impossibility result

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    © 2016 Elsevier B.V. All rights reserved. In this paper we show that, contrary to what is the case in what concerns contractions by a single sentence, there is not a system of spheres-based construction of multiple contractions which generates each and every transitively relational partial meet multiple contraction. Before proving the general result, we consider the class of system of spheres-based multiple contractions introduced in [17,5] and show that this class neither subsumes nor is subsumed by the class of transitively relational partial meet multiple contractions. Furthermore, we propose two system of spheres-based constructions of multiple contractions which generate (only) transitively relational partial meet multiple contractions. Therefore we can conclude that, although it is impossible to obtain a system of spheres-based definition of all the transitively relational partial meet multiple contractions, there are classes of system of spheres-based multiple contractions which are subsumed by the class of transitively relational partial meet multiple contractions

    Two axiomatic characterizations for the system of spheres-based (and the Epistemic Entrenchment-based) multiple contractions

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    © 2015, Springer International Publishing Switzerland. In some recent works (Reis 2011, Fermé and Reis, J. Philos. Log. 41, 29–52, 2012, Fermé and Reis, Rev. Symb. Log. 6, 460–487, 2013) two new kinds of multiple contraction functions have been proposed, namely the system of spheres-based multiple contractions and the epistemic entrenchment-based multiple contractions, as generalizations (to the case of multiple contraction) of the well-known classes of systems of spheres-based and of epistemic entrenchment-based (singleton) contractions. Additionally, a representation theorem for the class of epistemic entrenchment-based multiple contraction has been proposed, and it has been shown that the two newly proposed constructions are equivalent, in the sense that a multiple contraction function is a system of spheres-based multiple contraction if and only if it is an epistemic entrenchment-based multiple contraction. In this paper we present two axiomatic characterizations for those multiple contraction functions which differ from the one mentioned above and, in particular, make use of some more intuitive postulates
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