The statistics of catalogued quadruple stars consisting of two binaries (hierarchy 2+2) is studied in comparison with triple stars, with respective sample sizes of 81 and 724. Seven representative quadruple systems are discussed in greater detail. The main conclusions are: (i) Quadruple systems of ε Lyr type with similar masses and inner periods are common, in 42% of the sample the outer mass r...

Aims: Preterm labor (PTL) is one of the most important medical community problems and the main cause of infant morbidity and mortality after congenital anomalies. Several studies have shown a significant association between the abnormal levels of quadruple test with PTL. However, there is no general agreement on the value of quadruple tests for predicting complications among studies. This study...

Quadruple primary malignancies occur with an incidence of less than 0.1%. Only less than hundred cases have been published until today. The number of multiple malignancies reported is gradually increasing. Here, we present a female patient with a multiple sclerosis and quadruple cancers from different embryological origin. The patient had medullary thyroid carcinoma (stage III-T3, N1a, M0) and ...

Abstract As generalizations and alternatives of classical algebraic structures there have been introduced in 2019 the NeutroAlgebraic (or NeutroAlgebras) AntiAlgebraic AntiAlgebras). Unlike structures, where all operations are well defined axioms totally true, NeutroAlgebras AntiAlgebras, may be partially true or, respectively, outer-defined false. These AntiAlgebras form a new field research, ...

For various quadruple systems F , we give asymptotically sharp lower bounds on the number of copies of F in a quadruple system with a prescribed number of vertices and edges. Our results extend those of Füredi, Keevash, Pikhurko, Simonovits and Sudakov who proved under the same conditions that there is one copy of F . Our proofs use the hypergraph removal Lemma and stability results for the cor...