MAGELLAN/M2FS SPECTROSCOPY of the RETICULUM 2 DWARF SPHEROIDAL GALAXY

We present results from spectroscopic observations with the Michigan/Magellan Fiber System (M2FS) of 182 stellar targets along the line of sight to the newly-discovered `ultrafaint' object Reticulum 2 (Ret 2). For 38 of these targets, the spectra are sufficient to provide simultaneous estimates of line-of-sight velocity ($v_{\rm los}$, median random error $\delta_{v_{\rm los}}=1.3$ km s$^{-1}$), effective temperature ($T_{\rm eff}$, $\delta_{T_{\rm eff}}=464$ K), surface gravity ($\log g$, $\delta_{\rm logg}=0.54$ dex) and iron abundance ([Fe/H], $\delta_{\mathrm{[Fe/H]}}=0.45$ dex). We use these results to confirm 18 stars as members of Ret 2. From the member sample we estimate a velocity dispersion of $\sigma_{v_{\rm los}}=3.6_{-0.6}^{+0.9}$ km s$^{-1}$ about a mean of $\langle v_{\rm los}\rangle =64.8_{-1.0}^{+1.1}$ km s$^{-1}$ in the solar rest frame ($\sim -90.9$ km s$^{-1}$ in the Galactic rest frame), and a metallicity dispersion of $\sigma_{\rm [Fe/H]}=0.50_{-0.13}^{+0.17}$ dex about a mean of $\langle \mathrm{[Fe/H]} \rangle =-2.67_{-0.34}^{+0.34}$. These estimates marginalize over possible velocity and metallicity gradients, which are consistent with zero. Our results place Ret 2 on chemodynamical scaling relations followed by the Milky Way's dwarf-galactic satellites. Under assumptions of dynamic equilibrium and negligible contamination from binary stars---both of which must be checked with deeper imaging and repeat spectroscopic observations---the estimated velocity dispersion suggests a dynamical mass of $M(R_{\rm h})\approx 5R_{\rm h}\sigma_{v_{\rm los}}^2/(2G)=2.4_{-0.8}^{+1.3}\times 10^5$ $M_{\odot}$ enclosed within projected halflight radius $R_{\rm h}\sim 32$ pc, with mass-to-light ratio $\approx 2M(R_{\rm h})/L_{\rm V}=462_{-157}^{+264}$ in solar units

The test accuracy of antenatal ultrasound definitions of fetal macrosomia to predict birth injury: A systematic review.

OBJECTIVES: To determine which ultrasound measurement for predicted fetal macrosomia most accurately predicts adverse delivery and neonatal outcomes. STUDY DESIGN: Four biomedical databases searched for studies published after 1966. Randomised trials or observational studies of women with singleton pregnancies, resulting in a term birth who have undergone an index test of interest measured and recorded as predicted fetal macrosomia ≥28 weeks. Adverse outcomes of interest included shoulder dystocia, brachial plexus injury (BPI) and Caesarean section. RESULTS: Twenty-five observational studies (13,285 participants) were included. For BPI, the only significant positive association was found for Abdominal Circumference (AC) to Head Circumference (HC) difference > 50 mm (OR 7.2, 95 % CI 1.8-29). Shoulder dystocia was significantly associated with abdominal diameter (AD) minus biparietal diameter (BPD) ≥ 2.6 cm (OR 4.2, 95 % CI 2.3-7.5, PPV 11 %) and AC > 90th centile (OR 2.3, 95 % CI 1.3-4.0, PPV 8.6 %) and an estimated fetal weight (EFW) > 4000 g (OR 2.1 95 %CI 1.0-4.1, PPV 7.2 %). CONCLUSIONS: Estimated fetal weight is the most widely used ultrasound marker to predict fetal macrosomia in the UK. This study suggests other markers have a higher positive predictive value for adverse outcomes associated with fetal macrosomia

Simulating carbon capture by enhanced weathering with global croplands: an overview of key processes highlighting areas of future model development

Enhanced weathering (EW) aims to amplify a natural sink for CO2 by incorporating powdered silicate rock with high reactive surface area into agricultural soils. The goal is to achieve rapid dissolution of minerals and release of alkalinity with accompanying dissolution of CO2 into soils and drainage waters. EW could counteract phosphorus limitation and greenhouse gas (GHG) emissions in tropical soils, and soil acidification, a common agricultural problem studied with numerical process models over several decades. Here, we review the processes leading to soil acidification in croplands and how the soil weathering CO2 sink is represented in models. Mathematical models capturing the dominant processes and human interventions governing cropland soil chemistry and GHG emissions neglect weathering, while most weathering models neglect agricultural processes. We discuss current approaches to modelling EW and highlight several classes of model having the potential to simulate EW in croplands. Finally, we argue for further integration of process knowledge in mathematical models to capture feedbacks affecting both longer-term CO2 consumption and crop growth and yields

The role of primary healthcare professionals in oral cancer prevention and detection

AIM: To investigate current knowledge, examination habits and preventive practices of primary healthcare professionals in Scotland, with respect to oral cancer, and to determine any relevant training needs. SETTING: Primary care. METHOD: Questionnaires were sent to a random sample of 357 general medical practitioners (GMPs) and 331 dental practitioners throughout Scotland. Additionally, focus group research and interviews were conducted amongst primary healthcare team members. RESULTS: Whilst 58% of dental respondents reported examining regularly for signs of oral cancer, GMPs examined patients' mouths usually in response to a complaint of soreness. The majority of GMPs (85%) and dentists (63%) indicated that they felt less than confident in detecting oral cancer, with over 70% of GMPs identifying lack of training as an important barrier. Many practitioners were unclear concerning the relative importance of the presence of potentially malignant lesions in the oral cavity. A high proportion of the GMPs indicated that they should have a major role to play in oral cancer detection (66%) but many felt strongly that this should be primarily the remit of the dental team. CONCLUSION: The study revealed a need for continuing education programmes for primary care practitioners in oral cancer-related activities. This should aim to improve diagnostic skills and seek to increase practitioners' participation in preventive activities

The central image of a gravitationally lensed quasar

A galaxy can act as a gravitational lens, producing multiple images of a background object. Theory predicts there should be an odd number of images but, paradoxically, almost all observed lenses have 2 or 4 images. The missing image should be faint and appear near the galaxy's center. These ``central images'' have long been sought as probes of galactic cores too distant to resolve with ordinary observations. There are five candidates, but in one case the third image is not necessarily a central image, and in the others, the central component might be a foreground source rather than a lensed image. Here we report the most secure identification of a central image, based on radio observations of PMN J1632-0033, one of the latter candidates. Lens models incorporating the central image show that the mass of the lens galaxy's central black hole is less than 2 x 10^8 M_sun, and the galaxy's surface density at the location of the central image is more than 20,000 M_sun per square parsec, in agreement with expectations based on observations of galaxies hundreds of times closer to the Earth.Comment: Nature, in press [7 pp, 2 figs]. Standard media embargo applies before publicatio

Carbon Nanotubes Enhance Cytotoxicity Mediated by Human Lymphocytes In Vitro

With the expansion of the potential applications of carbon nanotubes (CNT) in biomedical fields, the toxicity and biocompatibility of CNT have become issues of growing concern. Since the immune system often mediates tissue damage during pathogenesis, it is important to explore whether CNT can trigger cytotoxicity through affecting the immune functions. In the current study, we evaluated the influence of CNT on the cytotoxicity mediated by human lymphocytes in vitro. The results showed that while CNT at low concentrations (0.001 to 0.1 µg/ml) did not cause obvious cell death or apoptosis directly, it enhanced lymphocyte-mediated cytotoxicity against multiple human cell lines. In addition, CNT increased the secretion of IFN-γ and TNF-α by the lymphocytes. CNT also upregulated the NF-κB expression in lymphocytes, and the blockage of the NF-κB pathway reduced the lymphocyte-mediated cytotoxicity triggered by CNT. These results suggest that CNT at lower concentrations may prospectively initiate an indirect cytotoxicity through affecting the function of lymphocytes

Economics methods in Cochrane systematic reviews of health promotion and public health related interventions.

Peer reviewedPublisher PD

The effectiveness of interventions to change six health behaviours: a review of reviews

Background: Several World Health Organisation reports over recent years have highlighted the high incidence of chronic diseases such as diabetes, coronary heart disease and cancer. Contributory factors include unhealthy diets, alcohol and tobacco use and sedentary lifestyles. This paper reports the findings of a review of reviews of behavioural change interventions to reduce unhealthy behaviours or promote healthy behaviours. We included six different health-related behaviours in the review: healthy eating, physical exercise, smoking, alcohol misuse, sexual risk taking (in young people) and illicit drug use. We excluded reviews which focussed on pharmacological treatments or those which required intensive treatments (e. g. for drug or alcohol dependency). Methods: The Cochrane Library, Database of Abstracts of Reviews of Effectiveness (DARE) and several Ovid databases were searched for systematic reviews of interventions for the six behaviours (updated search 2008). Two reviewers applied the inclusion criteria, extracted data and assessed the quality of the reviews. The results were discussed in a narrative synthesis. Results: We included 103 reviews published between 1995 and 2008. The focus of interventions varied, but those targeting specific individuals were generally designed to change an existing behaviour (e. g. cigarette smoking, alcohol misuse), whilst those aimed at the general population or groups such as school children were designed to promote positive behaviours (e. g. healthy eating). Almost 50% (n = 48) of the reviews focussed on smoking (either prevention or cessation). Interventions that were most effective across a range of health behaviours included physician advice or individual counselling, and workplace- and school-based activities. Mass media campaigns and legislative interventions also showed small to moderate effects in changing health behaviours. Generally, the evidence related to short-term effects rather than sustained/longer-term impact and there was a relative lack of evidence on how best to address inequalities. Conclusions: Despite limitations of the review of reviews approach, it is encouraging that there are interventions that are effective in achieving behavioural change. Further emphasis in both primary studies and secondary analysis (e.g. systematic reviews) should be placed on assessing the differential effectiveness of interventions across different population subgroups to ensure that health inequalities are addressed.</p

Novel Role of Phosphorylation-Dependent Interaction between FtsZ and FipA in Mycobacterial Cell Division

The bacterial divisome is a multiprotein complex. Specific protein-protein interactions specify whether cell division occurs optimally, or whether division is arrested. Little is known about these protein-protein interactions and their regulation in mycobacteria. We have investigated the interrelationship between the products of the Mycobacterium tuberculosis gene cluster Rv0014c-Rv0019c, namely PknA (encoded by Rv0014c) and FtsZ-interacting protein A, FipA (encoded by Rv0019c) and the products of the division cell wall (dcw) cluster, namely FtsZ and FtsQ. M. smegmatis strains depleted in components of the two gene clusters have been complemented with orthologs of the respective genes of M. tuberculosis. Here we identify FipA as an interacting partner of FtsZ and FtsQ and establish that PknA-dependent phosphorylation of FipA on T77 and FtsZ on T343 is required for cell division under oxidative stress. A fipA knockout strain of M. smegmatis is less capable of withstanding oxidative stress than the wild type and showed elongation of cells due to a defect in septum formation. Localization of FtsQ, FtsZ and FipA at mid-cell was also compromised. Growth and survival defects under oxidative stress could be functionally complemented by fipA of M. tuberculosis but not its T77A mutant. Merodiploid strains of M. smegmatis expressing the FtsZ(T343A) showed inhibition of FtsZ-FipA interaction and Z ring formation under oxidative stress. Knockdown of FipA led to elongation of M. tuberculosis cells grown in macrophages and reduced intramacrophage growth. These data reveal a novel role of phosphorylation-dependent protein-protein interactions involving FipA, in the sustenance of mycobacterial cell division under oxidative stress

The hidden giant: Discovery of an enormous Galactic dwarf satellite in Gaia DR2

We report the discovery of a Milky Way satellite in the constellation of Antlia. The Antlia 2 dwarf galaxy is located behind the Galactic disc at a latitude of b ~ 11° and spans 1.26°, which corresponds to ~2.9 kpc at its distance of 130 kpc. While similar in spatial extent to the Large Magellanic Cloud, Antlia 2 is orders of magnitude fainter at MV = −9 mag, making it by far the lowest surface brightness system known (at ∼31.9 mag arcsec−2), ~100 times more diffuse than the so-called ultra diffuse galaxies. The satellite was identified using a combination of astrometry, photometry, and variability data from Gaia Data Release 2, and its nature confirmed with deep archival DECam imaging, which revealed a conspicuous BHB signal. We have also obtained follow-up spectroscopy using AAOmega on the AAT, identifying 159 member stars, and we used them to measure the dwarf’s systemic velocity, 290.9 ± 0.5 km s−1, its velocity dispersion, 5.7 ± 1.1 km s−1, and mean metallicity, [Fe/H] = −1.4. From these properties we conclude that Antlia 2 inhabits one of the least dense dark matter (DM) haloes probed to date. Dynamical modelling and tidal-disruption simulations suggest that a combination of a cored DM profile and strong tidal stripping may explain the observed properties of this satellite. The origin of this core may be consistent with aggressive feedback, or may even require alternatives to cold dark matter (such as ultra-light bosons).Includes STFC