An Update on the 0Z Project

We give an update on our 0Z Survey to find more extremely metal poor (EMP) stars with [Fe/H] < -3 dex through mining the database of the Hamburg/ESO Survey. We present the most extreme such stars we have found from ~1550 moderate resolution follow up spectra. One of these, HE1424-0241, has highly anomalous abundance ratios not seen in any previously known halo giant, with very deficient Si, moderately deficient Ca and Ti, highly enhanced Mn and Co, and low C, all with respect to Fe. We suggest a SNII where the nucleosynthetic yield for explosive alpha-burning nuclei was very low compared to that for the hydrostatic alpha-burning element Mg, which is normal in this star relative to Fe. A second, less extreme, outlier star with high [Sc/Fe] has also been found. We examine the extremely metal-poor tail of the HES metallicity distribution function (MDF). We suggest on the basis of comparison of our high resolution detailed abundance analyses with [Fe/H](HES) for stars in our sample that the MDF inferred from follow up spectra of the HES sample of candidate EMP stars is heavily contaminated for [Fe/H](HES) < -3 dex; many of the supposed EMP stars below that metallicity are of substantially higher Fe-metallicity, including most of the very C-rich stars, or are spurious objects.Comment: to appear in conference proceedings "First Stars III", ed. B. O'Shea, A. Heger & T.Abel, 4 pages, 2 figure

The Evolution of Oxygen and Magnesium in the Bulge and Disk of the Milky Way

We show that the Galactic bulge and disk share a similar, strong, decline in [O/Mg] ratio with [Mg/H]. The similarity of the [O/Mg] trend in these two, markedly different, populations suggests a metallicity-dependent modulation of the stellar yields from massive stars, by mass loss from winds, and related to the Wolf-Rayet phenomenon, as proposed by McWilliam & Rich (2004). We have modified existing models for the chemical evolution of the Galactic bulge and the solar neighborhood with the inclusion of metallicity-dependent oxygen yields from theoretical predictions for massive stars that include mass loss by stellar winds. Our results significantly improve the agreement between predicted and observed [O/Mg] ratios in the bulge and disk above solar metallicity; however, a small zero-point normalization problem remains to be resolved. The zero-point shift indicates that either the semi-empirical yields of Francois et al. (2004) need adjustment, or that the bulge IMF is not quite as flat as found by Ballero et al. (2007); the former explanation is preferred. Our result removes a previous inconsistency between the interpretation of [O/Fe] and [Mg/Fe] ratios in the bulge, and confirms the conclusion that the bulge formed more rapidly than the disk, based on the over-abundances of elements produced by massive stars. We also provide an explanation for the long-standing difference between [Mg/Fe] and [O/Fe] trends among disk stars more metal-rich than the sun.Comment: 22 pages including 5 figures. Submitted to the Astronomical Journa

Hydrogen bonding in substituted nitroanilines : isolated nets in 1,3-diamino-4-nitrobenzene and continuously interwoven nets in 3,5-dinitroaniline

Peer reviewedPublisher PD

Coordinates and 2MASS and OGLE identifications for all stars in Arp's 1965 finding chart for Baade's Window

Aims: We seek to provide 2MASS and OGLE identifications and coordinates for all stars in the finding chart published by Arp\,(1965). This chart covers the low extinction area around NGC 6522, also known as Baade's window, at coordinates (l,b)=(1.02,-3.92). Methods: A cross correlation, using numerical techniques, was performed between a scan of the original finding chart from Arp (1965) and 2MASS and OGLE-II images and stellar coordinates. Results: We provide coordinates for all stars in Arp's finding chart and 2MASS and OGLE identifications wherever possible. Two identifications in quadrant II do not appear in the original finding chart.Comment: 30 pages, accepted by A&A as a Research Not

Characterisation and application of a bovine U6 promoter for expression of short hairpin RNAs

BackgroundThe use of small interfering RNA (siRNA) molecules in animals to achieve double-stranded RNA-mediated interference (RNAi) has recently emerged as a powerful method of sequence-specific gene knockdown. As DNA-based expression of short hairpin RNA (shRNA) for RNAi may offer some advantages over chemical and in vitro synthesised siRNA, a number of vectors for expression of shRNA have been developed. These often feature polymerase III (pol. III) promoters of either mouse or human origin.ResultsTo develop a shRNA expression vector specifically for bovine RNAi applications, we identified and characterised a novel bovine U6 small nuclear RNA (snRNA) promoter from bovine sequence data. This promoter is the putative bovine homologue of the human U6-8 snRNA promoter, and features a number of functional sequence elements that are characteristic of these types of pol. III promoters. A PCR based cloning strategy was used to incorporate this promoter sequence into plasmid vectors along with shRNA sequences for RNAi. The promoter was then used to express shRNAs, which resulted in the efficient knockdown of an exogenous reporter gene and an endogenous bovine gene.ConclusionWe have mined data from the bovine genome sequencing project to identify a functional bovine U6 promoter and used the promoter sequence to construct a shRNA expression vector. The use of this native bovine promoter in shRNA expression is an important component of our future development of RNAi therapeutic and transgenic applications in bovine species.<br /

Multiple primary tumours in a population-based series of patients with histopathologically peer-reviewed sarcomas.

Multiple primary tumours occurring in a three-year population-based series of patients with histopathologically peer-reviewed sarcomas from North West England were ascertained in order to look at the patterns of neoplasms seen. A total of 30 out of the 310 patients entered in the study had additional primary tumours. Very few patients were aged under 60 years at diagnosis of both their malignancies. The youngest was a known case of neurofibromatosis and, although seven patients were diagnosed with a sarcoma and carcinoma of the breast--a combination of cancers characteristic of the Li-Fraumeni cancer family syndrome--no other patients could directly be identified as suffering from any other cancer predisposition syndrome

Sarcomas in north west England: II. Incidence.

Incidence data on a population-based series of bone, soft tissue and visceral sarcomas from the North West of England are presented. The data are derived mainly from a total of 429 cases registered with the North Western Regional Cancer Registry and diagnosed during the period 1982-84, 76% of which were confirmed as sarcomas by a panel of five pathologists. Overall incidence of confirmed sarcomas per million person years was slightly higher in females (26.81) than in males (24.71) but there was no sex difference when 38 non-reviewed cases were taken into consideration (females 29.07, males (28.83). After exclusion of tumours of female genital tract, incidence of soft tissue tumours was very similar in both sexes (females 18.25, males 18.70). Bone tumours were almost twice as frequent in males (6.01) as in females (3.55)

Sarcomas in north west England: III. Survival.

Survival data on a population-based series of bone, soft tissue and visceral sarcomas diagnosed in the North West of England between 1982-84 and subjected to histopathological peer review are presented. Five-year crude survival for all cases was 34%. Survival in males and females did not differ significantly (P = 0.6, 5-year survival 32% vs 36%) but was markedly worse for patients diagnosed over the median age of 60 years, even when allowance was made for underlying mortality (P = 0.03, 34% vs 44%). Five-year survival rates for the major site groups were: bone 44%; soft tissues of head, neck and trunk 36%; soft tissues of extremities 35%; female genital tract 35%; retroperitoneum 15%; gastro-intestinal tract 13%. Analysis by the major histological types revealed the following survival rates: leiomyosarcoma--female genital tract 25%, gastro-intestinal tract 14%, non-visceral soft tissue 21%; malignant fibrous histiocytoma of soft tissue 29%; liposarcoma 52%; osteosarcoma of bone 46%; and chondrosarcoma of bone 50%

Damselfishes alleviate the impacts of sediments on host corals

Mutualisms play a critical role in ecological communities; however, the importance and prevalence of mutualistic associations can be modified by external stressors. On coral reefs, elevated sediment deposition can be a major stressor reducing the health of corals and reef resilience. Here, we investigated the influence of severe sedimentation on the mutualistic relationship between small damselfishes (Pomacentrus moluccensis and Dascyllus aruanus) and their coral host (Pocillopora damicornis). In an aquarium experiment, corals were exposed to sedimentation rates of approximately 100 mg cm−2 d−1, with and without fishes present, to test whether: (i) fishes influence the accumulation of sediments on coral hosts, and (ii) fishes moderate partial colony mortality and/or coral tissue condition. Colonies with fishes accumulated much less sediment compared with colonies without fishes, and this effect was strongest for colonies with D. aruanus (fivefold less sediment than controls) as opposed to P. moluccensis (twofold less sediment than controls). Colonies with symbiont fishes also had up to 10-fold less sediment-induced partial mortality, as well as higher chlorophyll and protein concentrations. These results demonstrate that fish mutualisms vary in the strength of their benefits, and indicate that some mutualistic or facilitative interactions might become more important for species health and resilience at high-stress levels