Search for direct pair production of the top squark in all-hadronic final states in proton-proton collisions at √s=8 TeV with the ATLAS detector

The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of 20.1fb−1 of proton-proton collision data at s√=8 TeV recorded with the ATLAS detector at the LHC are reported. The top squark is assumed to decay via t~→tχ~01 or t~→bχ~±1→bW(∗)χ~01, where χ~01 (χ~±1) denotes the lightest neutralino (chargino) in supersymmetric models. The search targets a fully-hadronic final state in events with four or more jets and large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits are reported in terms of the top squark and neutralino masses and as a function of the branching fraction of t~→tχ~01. For a branching fraction of 100%, top squark masses in the range 270-645 GeV are excluded for χ~01 masses below 30 GeV. For a branching fraction of 50% to either t~→tχ~01 or t~→bχ~±1, and assuming the χ~±1 mass to be twice the χ~01 mass, top squark masses in the range 250-550 GeV are excluded for χ~01 masses below 60 GeV.

A duplication in the canine beta-galactosidase gene GLB1 causes exon skipping and GM1-gangliosidosis in Alaskan huskies

GM(1)-gangliosidosis is a lysosomal storage disease that is inherited as an autosomal recessive disorder, predominantly caused by structural defects in the beta-galactosidase gene (GLB1). The molecular cause of GM(1)-gangliosidosis in Alaskan huskies was investigated and a novel 19-bp duplication in exon 15 of the GLB1 gene was identified. The duplication comprised positions +1688-+1706 of the GLB1 cDNA. It partially disrupted a potential exon splicing enhancer (ESE), leading to exon skipping in a fraction of the transcripts. Thus, the mutation caused the expression of two different mRNAs from the mutant allele. One transcript contained the complete exon 15 with the 19-bp duplication, while the other transcript lacked exon 15. In the transcript containing exon 15 with the 19-bp duplication a premature termination codon (PTC) appeared, but due to its localization in the last exon of canine GLB1, nonsense-mediated RNA decay (NMD) did not occur. As a consequence of these molecular events two different truncated GLB1 proteins are predicted to be expressed from the mutant GLB1 allele. In heterozygous carrier animals the wild-type allele produces sufficient amounts of the active enzyme to prevent clinical signs of disease. In affected homozygous dogs no functional GLB1 is synthesized and G(M1)-gangliosidosis occurs.