Ein SAT-Ansatz zur Cliquenweite von Digraphen und eine Anwendung auf das Zählen von Modellen

Zusammenfassung in deutscher SpracheAbweichender Titel nach Übersetzung der Verfasserin/des VerfassersIntroduced by Courcelle, Engelfriet, and Rozenberg, clique-width is a fundamental graph invariant that has been widely studied in discrete mathematics and computer science. Many hard problems on graphs and digraphs become tractable when restricted to graphs and digraphs of small clique-width, indeed solvable in linear time when restricted to classes of bounded clique-width. Clique-width is more general than treewidth, in the sense that algorithms parameterized by clique-width are effective on larger classes of instances than algorithms parameterized by treewidth (as there are graph classes of bounded clique-width where treewidth is unbounded, whereas small treewidth implies small clique-width). Typically algorithms for graphs of small clique-width require as input a certificate for small clique-width, which is already computationally hard to compute. In recent work Heule and Szeider presented a method for computing the clique-width of graphs based on an encoding to propositional satisfiability (SAT), which is then evaluated by a SAT solver, managing to discover the exact clique-width of various small graphs, previously unknown. Our main contribution is a generalization of the method by Heule and Szeider to directed graphs. Namely we present and implement an algorithm that, by invoking a SAT solver on a suitable instance, certifies the clique-width of a given directed graph. We exploit this implementation in two ways. First, we find the exact clique-width of various small directed graphs. Second, we implement an algorithm by Fischer, Makowsky, and Ravve and combine this and the aforementioned to an algorithm that counts models of CNFformulas of small directed incidence clique-width.4

A rare presentation of atretic parietal cephalocele

[Cukurova Med J 2016; 41(0.100): 132-133

Characteristics and outcomes of COVID-19 patients with IPF: A multi-center retrospective study.

BACKGROUND: : There are few data on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (COVID-19) infection in patients with idiopathic pulmonary fibrosis (IPF). The objective of this study is to describe the characteristics and outcomes of IPF patients confirmed COVID-19 infection. METHODS: : In this retrospective, multi-center, cohort study, patients from 4 hospital medical records with known IPF and a COVID-19 diagnosis were identified. Demographic and clinical outcome data were abstracted through a review of electronic medical records. RESULTS: : Records for 46 patients with IPF and COVID-19 were abstracted. The mean age was 65±10 years. The most common symptom was dyspnea, followed by fever and cough. Ground-glass opacities (n=35, 83.3%) and consolidations (n=11, 26.1%) were the main imaging features of the disease in thorax computed tomography (CT). Twenty-four patients (52.1%) required hospitalization. Among the hospitalized patients, 16 (66.6%) were admitted to the intensive care unit (ICU), and 10 (41.6%) underwent invasive mechanical ventilation. Thirteen patients (28.2%) died of COVID-19 complications. Mortality rate was significantly associated with lower DLCO/VA, long term oxygen therapy and consolidation finding on CT of thorax (p<0.05). On multivariable analysis, neither factor was associated with hospitalization or mortality. CONCLUSIONS: : IPF patients represent a vulnerable population for COVID-19, according to the high rate of hospitalization, ICU requirement and mortality rate. Measures to minimize the risk of COVID-19 infection remain key to protect IPF patients

The Prognostic Value Of Uhrf-1 And P53 In Gastric Cancer

Background/Aims: This study aimed to examine whether UHRF-1 and p53 overexpression is a prognostic marker for gastric cancer. Patients and Methods: Sixty-four patients with gastric cancer (study group) and 23 patients with gastritis (control group) were evaluated. Immunohistochemistry was used to examine expression of UHRF-1 and p53 in gastric cancers and a control group diagnosed with gastritis. Results: The median age was 63 years (18-83 years) in the study group. UHRF-1 was positive in 15 (23%) patients with gastric cancer and five (21.7%) patients with gastritis (P = 0.559). UHRF1 expression level in gastric cancer is more powerful than in gastritis (P = 0.046). Thirty-seven (61%) patients with gastric cancer and only one patient with gastritis were p53 positive (P < 0.001). After a median follow-up of 12 months (1–110), the 2-year overall survival rates were 55% and 30% in negative and positive p53, respectively (P = 0.084). Also, the 2-year overall survival rates were 45% and 53% in negative and positive UHRF-1, respectively (P = 0.132). Conclusion: According to this study, UHRF-1and p53 were not prognostic factors for gastric cancer, whereas they may have a diagnostic value for differantiating between gastric cancer and gastritis.PubMedWoSScopu