Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set

We report a measurement of the bottom-strange meson mixing phase \beta_s using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays in which the quark-flavor content of the bottom-strange meson is identified at production. This measurement uses the full data set of proton-antiproton collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity. We report confidence regions in the two-dimensional space of \beta_s and the B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2, -1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in agreement with the standard model expectation. Assuming the standard model value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +- 0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +- 0.009 (syst) ps, which are consistent and competitive with determinations by other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012

Blombos Cave, Southern Cape, South Africa: Preliminary Report on the 1992–1999 Excavations of the Middle Stone Age Levels

The Later- and Middle Stone Age levels at Blombos Cave (BBC) were excavated over four field seasons between 1992 and 1999. Here we report on the results from the Middle Stone Age (MSA) levels. The taphonomy and depositional history of the MSA levels is complex due to faulting, folding and spalling. Careful observations during excavation have assisted in understanding some of these taphonomic and site formation processes; microstratigraphic analysis, currently in progress, will add to this information. The uppermost MSA level, the Still Bay phase, contains high densities of bifacial points, the fossile directeur of the Still Bay Industry. Placing the Still Bay within the MSA culture sequence has been problematic in the past because Still Bay assemblages are rarely found in situ and previous excavations were inadequately recorded. However with the regional data discussed in the text, the Still Bay can be securely placed before the Howiesons Poort dated at 65–70 ka. Flaked stone makes up the greatest proportion of all artefacts with the highest incidence of retouch and use of fine grained, non-local materials found in the Still Bay levels. The ochre assemblage is remarkable for the mass of material compared to other MSA sites. Finds uncommon in an MSA context are two pieces of ochre from the Still Bay phase engraved with a geometric design; a fragment of deliberately engraved bone; also, 28 shaped and polished bone tools recovered mainly from a phase just below the Still Bay. Blombos Cave is the first site where well preserved faunal remains have been recovered in association with the Still Bay allowing for unique insights into human subsistence behaviour and palaeoenvironmental reconstruction. Large fish bones, marine shells, seals and dolphins attest to extensive exploitation of aquatic resources and a wide range of terrestrial animals were hunted and gathered. The few human teeth recovered are heavily worn and damaged thus the issue of morphological modernity cannot be addressed. The BBC findings are a useful ad

Stable carbon isotope analysis of the diets of West African bovids in Pendjari Biosphere Reserve, Northern Benin

Bovid diets have been studied for decades, but debate still exists about the diets of many species, in part because of geographical or habitat-related dietary variations. In this study we used stable carbon isotope analyses of faeces to explore the seasonal dietary preferences of 11 bovid species from a West African savanna, the Pendjari Biosphere Reserve (PBR), along the browser/grazer (or C3/C4) continuum.We compare our carbon isotope values with those for eastern and southern African bovids, as well as with dietary predictions based on continent-wide averages derived from field studies. Oribi and reedbuck, expected to be grazers were found to be predominantly C3-feeders (browsers) in the PBR. Bushbuck, common duiker and red-flanked duiker consumed more C4 grass than reported in previous studies. When comparing wet and dry season diets, kob, roan and oribi showed the least variation in C3 and C4 plant consumed proportions, while red-flanked duiker, bushbuck, reedbuck and waterbuck showed the most marked shifts. This study shows that animals in the better studied eastern and southern African savannas do not exhibit the full range of possible dietary adaptations. Inclusion of data from a wider geographical area to include less well-studied regions will inform our overall picture of bovid dietary ecology

The zebrafish reference genome sequence and its relationship to the human genome

Zebrafish have become a popular organism for the study of vertebrate gene function. The virtually transparent embryos of this species, and the ability to accelerate genetic studies by gene knockdown or overexpression, have led to the widespread use of zebrafish in the detailed investigation of vertebrate gene function and increasingly, the study of human genetic disease. However, for effective modelling of human genetic disease it is important to understand the extent to which zebrafish genes and gene structures are related to orthologous human genes. To examine this, we generated a high-quality sequence assembly of the zebrafish genome, made up of an overlapping set of completely sequenced large-insert clones that were ordered and oriented using a high-resolution high-density meiotic map. Detailed automatic and manual annotation provides evidence of more than 26,000 protein-coding genes, the largest gene set of any vertebrate so far sequenced. Comparison to the human reference genome shows that approximately 70% of human genes have at least one obvious zebrafish orthologue. In addition, the high quality of this genome assembly provides a clearer understanding of key genomic features such as a unique repeat content, a scarcity of pseudogenes, an enrichment of zebrafish-specific genes on chromosome 4 and chromosomal regions that influence sex determination