GavaghanCommunications | Science for scientists. Issue 4: 1 - 6.9.10.

Item 1: Keywords.
HapMap 3,

Initial analysis of expanded HapMap (HapMap 3) database with attention to the quality of imputation across populations.

Haplotype is defined in Genome by TA Brown (1999), Bios Scientific Publishing, as a collection of alleles that are usually inherited together.

The HapMap 3 consortium gives in Nature, 2.9.10, a report of population genetic data analysis (some comparative) from 11 population groups from Asia, Africa, Europe and admixed groups from the US. They characterised single nucleotide polymorphisms and copy number polymorphisms (with deletions and duplications) from existing microarray data and additional new raw data obtained by sequencing PCR amplified 100 kb regions. SNPs detected from sequence data give a direct measure, they write, of the alleles with a minor frequency (minor allele frequency - MAF - less than or equal to 5 per cent). 77 per cent of the alleles (correction within 24 hours of publishing, this should read SNPs not alleles) discovered were not in the SNP database, and of these 99 per cent were associated with a MAF.

Proof reading correction: The previous sentence should say 77 per cent of SNPs were not in the SNP database, not of alleles. This was a proof reading error not an error in understanding. HG.

The consortium observed that copy number polymorphisms with an allele frequency greater than or equal to 10 per cent were similar across populations but differed considerably at lower frequencies.

To explore the effectiveness of imputation of missing data the consortium explored the haplotype background of alleles and found that imputation worked well for common alleles across closely related populations but not for low frequency alleles. Published 3.9.10.

Based on a paper published in Nature 2.9.10: Intergrating common and rare genetic variations in diverse human populations by The International HapMap 3 Consortium. DOI:10.1038/nature09298.

15th September 2010: Leeds City Library to host 9 'til 1 an open,
free event which Patent Office staff and patent attornies will attend.
Useful websites.,

Item 2: Keywords.
Quantum communication,
quantum repeaters,
megahertz transmission.

A bilateral linear design for quantum communication by entanglement swapping that demonstrates the potential feasibility for quantum communication networks with megahertz transmission rates.

Entanglement swapping at nodes between leftmost and rightmost nodes having established entanglement, coupled with error correction at nodes for such observed phenomena as deviations from a Pauli frame, suggest the possibility of a rate of 2500 entangled pairs per second and hint at megahertz rates. The design lessens the time for which a qubit needs to be held in a quantum memory, interpreted by the authors as possibly decreasing the technical demands of memory in distributed quantum information processing. In the scheme discussed in this paper transmission between nodes rather than over the whole network is the limiting parameter for entanglement generation, and the authors presented discussion built around nodal separations of 40 km. Published by GavaghanCommunications 2.9.10.

Based on the paper: "From quantum multiplexing to high-performance quantum networking", by W.J.Munro et al. DOI:10.1038/NPHOTON.2010.213.Nature Photonics, 29th August, 2010.

Useful inhouse references owned by Science, People and Politics Ltd.: An introduction to quantum mechanics, by P.T.Matthews FRS. Third edition. 1974. McGraw-Hill Book Company (UK) Ltd. and Statistical Physics, by Arthur Brown. 1968. Edinburgh University Press. Science, People and Politics Ltd. does not own the title Snippets of science.

Snippets of science by Helen Gavaghan©