We say that a 0–1 matrix N of size a × b can be found in a collection of sets H if we can find sets H1, H2, . . . , Ha in H and elements e1, e2, . . . , eb in ∪H∈HH such that N is the incidence matrix of the sets H1, H2, . . . , Ha over the elements e1, e2, . . . , eb. We prove the following Ramsey-type result: for every n ∈ N, there exists a number S(n) such that in any collection of at least ...

Gene duplication enables the functional diversification in species. It is thought that duplicated genes may be able to compensate if the function of one of the gene copies is disrupted. This possibility is extensively debated with some studies reporting proteome-wide compensation, whereas others suggest functional compensation among only recent gene duplicates or no compensation at all. We repo...

Low birth weight is associated with postnatal physiological changes, including impaired glucose tolerance and increased cortisol secretion, that may predispose to disease in adulthood. Twins are born lighter than singletons, but there are conflicting data regarding the association between birth weight and postnatal physiology in twins. We studied glucose tolerance and ACTH and cortisol response...

Using data from the Missouri maternally linked files (1989-1997), the authors examined the association among maternal obesity, obesity subtypes, and spontaneous and medically indicated preterm (<37 weeks) and very preterm (<33 weeks) births in singletons and twins. Adjusted odds ratios were obtained with correction for intracluster correlation. The prevalence of obesity increased by 77% over th...

BACKGROUND The use of expensive infertility treatments is increasing rapidly. To compare the prenatal and neonatal health care costs after IVF and spontaneous conception, we conducted a study based on a cohort of IVF and control pregnancies and neonates. METHODS A cohort of 215 IVF mothers and 255 IVF neonates were compared with a cohort of 662 control mothers and 388 control children, random...

OBJECTIVES To estimate long term health service costs for hospital stays associated with singleton, twin, and higher order multiple births up to 5 years of age. DESIGN Costs from specialty based data from the English Department of Health's NHS Trust Financial Returns were applied to admissions recorded in the Oxford record linkage study during 1970-1993. SETTING Oxfordshire and West Berkshi...

OBJECTIVE To compare the growth and development of twins with normal control singletons and also with matched 'high risk' singletons, at one and four years of age. DESIGN A four year prospective follow up study. SETTING High risk clinic (HRC) of a referral hospital. SUBJECTS Twin pairs enrolled in the HRC; normal full term singleton controls; and high risk "matched" singletons enrolled in...

Twin registries around the globe have collected DNA samples from large numbers of monozygotic and dizygotic twins. The twin sample collections are frequently used as controls in disease-specific studies together with non-twins. This approach is unbiased under the hypothesis that twins and singletons are comparable in terms of allele frequencies; i.e. there are no genetic variants associated wit...

BACKGROUND It has been claimed that the risks to the child resulting from vitrification as compared with the slow-freezing technique, may be higher owing to the high concentrations of potentially toxic cryoprotectants. We therefore retrospectively compared the obstetric and neonatal outcomes in a cohort of children born after transfer of vitrified blastocysts, fresh blastocysts and slow-frozen ...

Fock module realization for the unitary singleton representations of the d − 1 dimensional conformal algebra o(d − 1, 2), which correspond to the spaces of single-particle states of massless scalar and spinor in d− 1 dimensions, is given. The pattern of the tensor product of a pair of singletons is analyzed in any dimension. It is shown that for d > 3 the tensor product of two boson singletons ...