Antibias in Clusters: The Dependence of M/L on Cluster Temperature

We show that the observed mass-to-light ratio of galaxy clusters increases with cluster temperature as expected from cosmological simulations. Contrary to previous observational suggestions, we find a mild but robust increase of M/L from poor (T = 1 - 2 keV) to rich (T = 12 keV) clusters; over this range, the mean M/L_V increases by a factor of about 2. The best fit relation satisfies M/L_V = (170 +- 30) T(keV)^(0.3 +- 0.1) h at z=0, with a large scatter. This trend confirms predictions from cosmological simulations which show that the richest clusters are antibiased, with a higher ratio of mass per unit light than average. The antibias increases with cluster temperature. The effect is caused by the relatively older age of the high-density clusters, where light has declined more significantly than average since their earlier formation time. Combining the current observations with simulations, we find a global value of M/L_V = 240 +- 50 h, and a corresponding mass density of the universe of Omega_m = 0.17 +- 0.05.Comment: 12 pages, 3 figs, minor changes, to be published in ApJL, Vol. 565 (Jan. 20, 2002

Controls on geothermal heat recovery from a hot sedimentary aquifer in Guardbridge, Scotland:Field measurements, modelling and long term sustainability

Geothermal heat from Hot Sedimentary Aquifers represents a promising intermediate (30°C) resource for district heating systems. A key control on the geothermal productivity of these aquifers is the architecture of faults, which can significantly enhance or reduce the natural permeability of these systems. We present the first three-dimensional coupled groundwater flow and heat transport numerical model, combining multiple data from field mapping and fracture surveys, of two intersecting major fault systems in Central-East Scotland. This includes fault-zone fracture permeability modelling, depth-dependent permeability modelling, geo-mechanical facies assessment and heat productivity estimates for single well and multiple well extraction scenarios. Simulations indicate that with careful location of extraction wells within permeable fault systems, production is sustainable for over 50 years for multiple-well extraction scenarios in this region

Testing hydrostatic equilibrium in galaxy cluster MS 2137

We test the assumption of strict hydrostatic equilibrium in galaxy cluster MS2137.3-2353 (MS 2137) using the latest CHANDRA X-ray observations and results from a combined strong and weak lensing analysis based on optical observations. We deproject the two-dimensional X-ray surface brightness and mass surface density maps assuming spherical and spheroidal dark matter distributions. We find a significant, 40%-50%, contribution from non-thermal pressure in the core assuming a spherical model. This non-thermal pressure support is similar to what was found by Molnar et al. (2010) using a sample of massive relaxed clusters drawn from high resolution cosmological simulations. We have studied hydrostatic equilibrium in MS 2137 under the assumption of elliptical cluster geometry adopting prolate models for the dark matter density distribution with different axis ratios. Our results suggest that the main effect of ellipticity (compared to spherical models) is to decrease the non-thermal pressure support required for equilibrium at all radii without changing the distribution qualitatively. We find that a prolate model with an axis ratio of 1.25 (axis in the line of sight over perpendicular to it) provides a physically acceptable model implying that MS 2137 is close to hydrostatic equilibrium at about 0.04-0.15 Rvir and have an about 25% contribution from non-thermal pressure at the center. Our results provide further evidence that there is a significant contribution from non-thermal pressure in the core region of even relaxed clusters, i.e., the assumption of hydrostatic equilibrium is not valid in this region, independently of the assumed shape of the cluster.Comment: 11 pages, 4 figures, accepted for publication in Ap

Developing a timeline for evaluating public health nutrition policy interventions: what are the outcomes and when should we expect to see them?

Objective: To develop a timeline for evaluating public health nutrition policy interventions. Design: Concept mapping, a stakeholder-driven approach for developing an evaluation framework to estimate the ‘time to impact’ for policy interventions. The Schools (Health Promotion and Nutrition) (Scotland) Act 2007 was used as the model to develop the evaluation timeline as it had typical characteristics of government policy. Concept mapping requires stakeholders to generate a list of the potential outcomes, sort and rate the outcomes. Multidimensional scaling and hierarchical cluster data analysis were used to develop an anticipated timeline to impact for the policy. Setting: United Kingdom. Subjects: One hundred and eleven stakeholders representing nutrition, public health, medicine, education and catering in a range of sectors: research, policy, local government, National Health Service and schools. Results: Eighty-five possible outcomes were identified and grouped into thirteen clusters describing higher-level themes (e.g. long-term health, food literacy, economics, behaviour, diet, education). Negative and unintended consequences were anticipated relatively soon after implementation of the policy, whereas positive outcomes (e.g. dietary changes, health benefits) were thought likely to take longer to emerge. Stakeholders responsible for implementing the legislation anticipated that it would take longer to observe changes than those from policy or research. Conclusions: Developing an anticipated timeline provides a realistic framework upon which to base an outcome evaluation for policy interventions and identifies positive and negative outcomes as well as considering possible unintended consequences. It offers benefit to both policy makers and researchers in mapping the progress expected towards long-term health goals and outcomes

Quadratic equations over free groups are NP-complete

We prove that the problems of deciding whether a quadratic equation over a free group has a solution is NP-complete

PI3Kgamma drives priming and survival of autoreactive CD4(+) T cells during experimental autoimmune encephalomyelitis

The class IB phosphoinositide 3-kinase γ enzyme complex (PI3Kc) functions in multiple signaling pathways involved in leukocyte activation and migration, making it an attractive target in complex human inflammatory diseases including MS. Here, using pik3cg2/2 mice and a selective PI3Kc inhibitor, we show that PI3Kc promotes development of experimental autoimmune encephalomyelitis (EAE). In pik3cg2/2 mice, EAE is markedly suppressed and fewer leukocytes including CD4+ and CD8+ T cells, granulocytes and mononuclear phagocytes infiltrate the CNS. CD4+ T cell priming in secondary lymphoid organs is reduced in pik3cg2/2 mice following immunisation. This is attributable to defects in DC migration concomitant with a failure of full T cell activation following TCR ligation in the absence of p110c. Together, this results in suppressed autoreactive T cell responses in pik3cg2/2 mice, with more CD4+ T cells undergoing apoptosis and fewer cytokineproducing Th1 and Th17 cells in lymphoid organs and the CNS. When administered from onset of EAE, the orally active PI3Kc inhibitor AS605240 caused inhibition and reversal of clinical disease, and demyelination and cellular pathology in the CNS was reduced. These results strongly suggest that inhibitors of PI3Kc may be useful therapeutics for MS.Iain Comerford, Wendel Litchfield, Ervin Kara and Shaun R. McCol

Relationship between Tibial conformation, cage size and advancement achieved in TTA procedure

Previous studies have suggested that there is a theoretical discrepancy between the cage size and the resultant tibial tuberosity advancement, with the cage size consistently providing less tibial tuberosity advancement than predicted. The purpose of this study was to test and quantify this in clinical cases. The hypothesis was that the advancement of the tibial tuberosity as measured by the widening of the proximal tibia at the tibial tuberosity level after a standard TTA, will be less than the cage sized used, with no particular cage size providing a relative smaller or higher under-advancement, and that the conformation of the proximal tibia will have an influence on the amount of advancement achieved

In vivo dual RNA-seq reveals that neutrophil recruitment underlies differential tissue tropism of Streptococcus pneumoniae.

Streptococcus pneumoniae is a genetically diverse human-adapted pathogen commonly carried asymptomatically in the nasopharynx. We have recently shown that a single nucleotide polymorphism (SNP) in the raffinose pathway regulatory gene rafR accounts for a difference in the capacity of clonally-related strains to cause localised versus systemic infection. Using dual RNA-seq, we show that this SNP affects expression of bacterial genes encoding multiple sugar transporters, and fine-tunes carbohydrate metabolism, along with extensive rewiring of host transcriptional responses to infection, particularly expression of genes encoding cytokine and chemokine ligands and receptors. The data predict a crucial role for differential neutrophil recruitment (confirmed by in vivo neutrophil depletion and IL-17 neutralization) indicating that early detection of bacteria by the host in the lung environment is crucial for effective clearance. Thus, dual RNA-seq provides a powerful tool for understanding complex host-pathogen interactions and reveals how a single bacterial SNP can drive differential disease outcomes

A comparison of the strong lensing properties of the Sersic and the NFW profiles

We investigate the strong lensing properties of the Sersic profile as an alternative to the NFW profile, focusing on applications to lens modelling of clusters. Given an underlying Sersic dark matter profile, we study whether an NFW profile can provide an acceptable fit to strong lensing constraints in the form of single or multiple measured Einstein radii. We conclude that although an NFW profile that fits the lensing constraints can be found in many cases, the derived parameters may be biased. In particular, we find that for n~2, which corresponds to massive clusters, the mass at r_200 of the best fit NFW is overestimated (by a factor of ~2) and the concentration is very low (c~2). The differences are important enough to warrant the inclusion of Sersic profile for future analysis of strong lensing clusters.Comment: 19 pages (single column format), 11 figures. Accepted for publication by JCA

Multiple functions of CXCL12 in a syngeneic model of breast cancer

BACKGROUND: A growing body of work implicates chemokines, in particular CXCL12 and its receptors, in the progression and site-specific metastasis of various cancers, including breast cancer. Various agents have been used to block the CXCL12-CXCR4 interaction as a means of inhibiting cancer metastasis. However, as a potent chemotactic factor for leukocytes, CXCL12 also has the potential to enhance anti-cancer immunity. To further elucidate its role in breast cancer progression, CXCL12 and its antagonist CXCL12(P2G) were overexpressed in the syngeneic 4T1.2 mouse model of breast carcinoma. RESULTS: While expression of CXCL12(P2G) significantly inhibited metastasis, expression of wild-type CXCL12 potently inhibited both metastasis and primary tumor growth. The effects of wild-type CXCL12 were attributed to an immune response characterized by the induction of CD8+ T cell activity, enhanced cell-mediated cytotoxicity, increased numbers of CD11c+ cells in the tumor-draining lymph nodes and reduced accumulation of myeloid-derived suppressor cells in the spleen.CONCLUSIONS: This study highlights the need to consider carefully therapeutic strategies that block CXCL12 signaling. Therapies that boost CXCL12 levels at the primary tumor site may prove more effective in the treatment of metastatic breast cancer.Sharon A Williams, Yuka Harata-Lee, Iain Comerford, Robin L Anderson, Mark J Smyth and Shaun R McCol