QRAT+: Generalizing QRAT by a More Powerful QBF Redundancy Property

The QRAT (quantified resolution asymmetric tautology) proof system simulates virtually all inference rules applied in state of the art quantified Boolean formula (QBF) reasoning tools. It consists of rules to rewrite a QBF by adding and deleting clauses and universal literals that have a certain redundancy property. To check for this redundancy property in QRAT, propositional unit propagation (UP) is applied to the quantifier free, i.e., propositional part of the QBF. We generalize the redundancy property in the QRAT system by QBF specific UP (QUP). QUP extends UP by the universal reduction operation to eliminate universal literals from clauses. We apply QUP to an abstraction of the QBF where certain universal quantifiers are converted into existential ones. This way, we obtain a generalization of QRAT we call QRAT+. The redundancy property in QRAT+ based on QUP is more powerful than the one in QRAT based on UP. We report on proof theoretical improvements and experimental results to illustrate the benefits of QRAT+ for QBF preprocessing.Comment: preprint of a paper to be published at IJCAR 2018, LNCS, Springer, including appendi

Cyclosporin in atopic dermatitis: A multicentre placebo-controlled study

The efficacy of cyclosporin (Sandimmun®) given in a daily dose of 5 mg/kg for 6 weeks in severe atopic dermatitis was confirmed in this double-blind, placebo-controlled, short-term study. Of the 46 patients included in the study, 23 were randomized to receive cyclosporin and 23 to receive placebo. Four of the 23 patients (17%) on cyclosporin, and 14 of the 23 patients (61%) who received placebo, discontinued the trial because of inefficacy. All patients who discontinued the trial were assessed following the principle the principle of ‘intention to treat’. Compared with the baseline, the mean scores for disease severity [6-area, total body severity assessment (TBSA)] improved by 55%, and the mean scores for extent of disease [rule-of-nines area assessment (RoNAA)] improved by 40%, in patients treated with cyclosporin. Nine of the patients who received cyclosporin and completed the study (n=14) had an individual reduction of disease severity (TBSA) of 75% or more, and in three patients this reduction was nearly 100%. In the placebo group, a mean worsening of disease severity (4%) and of extent of the disease (25%), compared with the baseline, was observed al week 6. Patients' and investigators' mean scores for the overall efficacy were similar, and showed a statistically significant difference in favour of cyclosporin. Two patients on cyclosporin developed hypertension during therapy, and one of these withdrew from the study. At the end of the trial, no statistically significant differences in the systolic or diastolic blood pressures were observed between the two groups. In the cyclosporin group, the increases in the values of serum creatinine and bilirubin at week 6, compared with the respective values at the baseline, were statistically significantly different from those in the placebo group, but all values normalized in the post-treatment period. Cyclosporin can be a safe and very effective treatment in episodes of severe atopic dermatitis, provided that the recommended guidelines for its administration are strictly observed

Somatostatin receptor scintigraphy in cutaneous malignant lymphomas

Background: Lymphoid cells may express somatostatin receptors (SS-Rs) on their cell surface. Therefore radiolabeled somatostalin analogues may be used to visualize SS-R-positive lymphoid neoplasms in vivo. Exact staging is the basis for treatment decisions in cutaneous malignant lymphoma. We considered the possibility that SS-R scintigraphy might offer a clinically useful method of diagnostic imaging in patients with cutaneous malignant lymphoma. Objective: We evaluated SS-R scintigraphy in comparison with conventional staging methods in the staging of cutaneous malignant lymphoma. Methods: We conducted a prospective study in 14 consecutive patients with histologically proven cutaneous malignant lymphoma. SS-R scintigraphy was compared with physical, radiologic, and bone marrow examinations. Lymph node excisions were performed in patients with palpable lymph nodes. Results: SS-R scintigraphy was positive in the lymph nodes in all four patients with malignant lymph node infiltration and negative in the three patients with dermatopathic lymphadenopathy. In two patients, previously unsuspected lymphoma localizations were visualized by SS-R scintigraphy. In only three patients all skin lesions were visualized by SS-R scintigraphy; these three patients had not been treated with topical corticosteroids. SS-R scintigraphy failed to detect an adrenal mass in one patient and bone marrow infiltration in two patients. Conclusion: SS-R scintigraphy may help distinguish dermatopathic lymphadenopathy from malignant lymph node infiltration in patients with cutaneous malignant lymphoma

On QBF Proofs and Preprocessing

QBFs (quantified boolean formulas), which are a superset of propositional formulas, provide a canonical representation for PSPACE problems. To overcome the inherent complexity of QBF, significant effort has been invested in developing QBF solvers as well as the underlying proof systems. At the same time, formula preprocessing is crucial for the application of QBF solvers. This paper focuses on a missing link in currently-available technology: How to obtain a certificate (e.g. proof) for a formula that had been preprocessed before it was given to a solver? The paper targets a suite of commonly-used preprocessing techniques and shows how to reconstruct certificates for them. On the negative side, the paper discusses certain limitations of the currently-used proof systems in the light of preprocessing. The presented techniques were implemented and evaluated in the state-of-the-art QBF preprocessor bloqqer.Comment: LPAR 201

DepQBF 6.0: A Search-Based QBF Solver Beyond Traditional QCDCL

We present the latest major release version 6.0 of the quantified Boolean formula (QBF) solver DepQBF, which is based on QCDCL. QCDCL is an extension of the conflict-driven clause learning (CDCL) paradigm implemented in state of the art propositional satisfiability (SAT) solvers. The Q-resolution calculus (QRES) is a QBF proof system which underlies QCDCL. QCDCL solvers can produce QRES proofs of QBFs in prenex conjunctive normal form (PCNF) as a byproduct of the solving process. In contrast to traditional QCDCL based on QRES, DepQBF 6.0 implements a variant of QCDCL which is based on a generalization of QRES. This generalization is due to a set of additional axioms and leaves the original Q-resolution rules unchanged. The generalization of QRES enables QCDCL to potentially produce exponentially shorter proofs than the traditional variant. We present an overview of the features implemented in DepQBF and report on experimental results which demonstrate the effectiveness of generalized QRES in QCDCL.Comment: 12 pages + appendix; to appear in the proceedings of CADE-26, LNCS, Springer, 201

Evaluation of Sensititre Broth Microdilution Plate for determining the susceptibility of carbapenem-resistant Klebsiella pneumoniae to polymyxins

Colistin and polymyxin B MICs were determined for 106 carbapenem-resistant Klebsiella pneumoniae (CR-Kp) isolates using Sensititre Research Use Only GNX2F plates (Thermo Fisher) and compared to CLSI broth macrodilution (BMD) as the reference method. For colistin, EUCAST breakpoints were applied and testing of isolates with very major (VM) errors was repeated in duplicate by both methods to determine a majority result. Essential agreement (MIC ± one dilution) of GNX2F with the reference method was 97.1% for polymyxin B and 92.5% for colistin (7 VM errors, 22.6%). After discrepancy testing, there were 28 colistin resistant isolates by BMD and essential agreement was 94.3% with 4 VM errors (14.3%). Colistin and polymyxin B GNX2F results showed acceptable essential agreement with BMD for MICS without interpretation. Colistin VM errors with EUCAST breakpoints were due to MIC variability in the 2 to 4 μg/mL range that could be addressed by establishing an intermediate category

Musée archéologique Liégeois : guide sommaire /

Boven de titel: Ville de Liege

From Cliques to Colorings and Back Again

We present an exact algorithm for graph coloring and maximum clique problems based on SAT technology. It relies on four sub-algorithms that alternatingly compute cliques of larger size and colorings with fewer colors. We show how these techniques can mutually help each other: larger cliques facilitate finding smaller colorings, which in turn can boost finding larger cliques. We evaluate our approach on the DIMACS graph coloring suite. For finding maximum cliques, we show that our algorithm can improve the state-of-the-art MaxSAT-based solver IncMaxCLQ, and for the graph coloring problem, we close two open instances, decrease two upper bounds, and increase one lower bound