Identification of the Kna/Knb polymorphism and a method for Knops genotyping

BACKGROUND: DNA mutations resulting in the McCoy and Swain-Langley polymorphisms have been identified on complement receptor 1 (CR1)—a ligand for rosetting of Plasmodium falciparum-infected RBCs. The molecular identification of the Kn(a)/Kn(b) polymorphism was sought to develop a genotyping method for use in the study of the Knops blood group and malaria. STUDY DESIGN AND METHODS: CR1 deletion constructs were used in inhibition studies of anti-Kn(a). PCR amplification of Exon 29 was followed by DNA sequencing. A PCR-RFLP was developed with NdeI, BsmI, and MfeI for the detection of Kn(a)/Kn(b), McC(a)/McC(b), and Sl1/Sl2, respectively. Knops phenotypes were determined with standard serologic techniques. RESULTS: A total of 310 Malian persons were phenotyped for Kn(a) with 200 (64%) Kn(a+) and 110 (36%) Kn(a−). Many of the Kn(a−) exhibited the Knops-null phenotype, that is, Helgeson. The Kn(a/b) DNA polymorphism was identified as a V1561M mutation with allele frequencies of Kn(a) (V1561) 0.9 and Kn(b) (M1561) 0.1. CONCLUSION: The high frequency (18%) of Kn(b) in West African persons suggests that it is not solely a Caucasian trait. Furthermore, because of the high incidence of heterozygosity as well as amorphs, accurate Knops typing of donors of African descent is best accomplished by a combination of molecular and serologic techniques

The monotonicity of f-vectors of random polytopes

Let K be a compact convex body in Rd, let Kn be the convex hull of n points chosen uniformly and independently in K, and let fi(Kn) denote the number of i-dimensional faces of Kn. We show that for planar convex sets, E(f0(Kn)) is increasing in n. In dimension d>=3 we prove that if lim(E((f[d -1](Kn))/(An^c)->1 when n->infinity for some constants A and c > 0 then the function E(f[d-1](Kn)) is increasing for n large enough. In particular, the number of facets of the convex hull of n random points distributed uniformly and independently in a smooth compact convex body is asymptotically increasing. Our proof relies on a random sampling argument

Final report on the force key comparison CCM.F-K3

In the Force Key Comparison CCM.F-K3 the measurand force was compared at the two force steps 500 kN and 1 MN. 12 laboratories participated in this comparison which was organised by PTB as the pilot laboratory in two laboratory groups (group A and B). In group A, the comparison was carried out with two 1 MN compression force transducers at the two force steps 500 kN and 1 MN (CCM.F-K3a) and with 6 participating laboratories. In group B, the comparison was carried out with two 500 kN compression force transducers at one force step of 500 kN (CCM.F-K3b) and with 9 participating laboratories. The key comparison reference values were determined as the weighted mean of all results for the two force steps and set to 500 kN and 1 MN, respectively, with the associated uncertainties. The degrees of equivalence were determined for all 12 laboratories for 500 kN compression force and for 6 laboratories for 1 MN compression force

Second Order Approximations for Slightly Trimmed Sums

We investigate the second order asymptotic behavior of trimmed sums T_n=\frac 1n \sum_{i=\kn+1}^{n-\mn}\xin, where \kn, \mn are sequences of integers, 0\le \kn < n-\mn \le n, such that \min(\kn, \mn) \to \infty, as \nty, the \xin's denote the order statistics corresponding to a sample $X_1,...,X_n$ of $n$ i.i.d. random variables. In particular, we focus on the case of slightly trimmed sums with vanishing trimming percentages, i.e. we assume that \max(\kn,\mn)/n\to 0, as \nty, and heavy tailed distribution $F$, i.e. the common distribution of the observations $F$ is supposed to have an infinite variance. We derive optimal bounds of Berry -- Esseen type of the order $O\bigl(r_n^{-1/2}\bigr)$, r_n=\min(\kn,\mn), for the normal approximation to $T_n$ and, in addition, establish one-term expansions of the Edgeworth type for slightly trimmed sums and their studentized versions. Our results supplement previous work on first order approximations for slightly trimmed sums by Csorgo, Haeusler and Mason (1988) and on second order approximations for (Studentized) trimmed sums with fixed trimming percentages by Gribkova and Helmers (2006, 2007).Comment: 37 pages, to appear in Theory Probab. App