A self-consistent, absolute isochronal age scale for young moving groups in the solar neighbourhood

This is a pre-copyedited, author-produced PDF of an article accepted for publication in MNRAS following peer review. The version of record is available online at: http://mnras.oxfordjournals.org/content/454/1/593.We present a self-consistent, absolute isochronal age scale for young (< 200 Myr), nearby (< 100 pc) moving groups in the solar neighbourhood based on homogeneous fitting of semi-empirical pre-main-sequence model isochrones using the tau^2 maximum-likelihood fitting statistic of Naylor & Jeffries in the M_V, V-J colour-magnitude diagram. The final adopted ages for the groups are: 149+51-19 Myr for the AB Dor moving group, 24+/-3 Myr for the {\beta} Pic moving group (BPMG), 45+11-7 Myr for the Carina association, 42+6-4 Myr for the Columba association, 11+/-3 Myr for the {\eta} Cha cluster, 45+/-4 Myr for the Tucana-Horologium moving group (Tuc-Hor), 10+/-3 Myr for the TW Hya association, and 22+4-3 Myr for the 32 Ori group. At this stage we are uncomfortable assigning a final, unambiguous age to the Argus association as our membership list for the association appears to suffer from a high level of contamination, and therefore it remains unclear whether these stars represent a single population of coeval stars. Our isochronal ages for both the BPMG and Tuc-Hor are consistent with recent lithium depletion boundary (LDB) ages, which unlike isochronal ages, are relatively insensitive to the choice of low-mass evolutionary models. This consistency between the isochronal and LDB ages instills confidence that our self-consistent, absolute age scale for young, nearby moving groups is robust, and hence we suggest that these ages be adopted for future studies of these groups. Software implementing the methods described in this study is available from http: //www.astro.ex.ac.uk/people/timn/tau-squared/.University of Rochester School of Arts and SciencesNational Science Foundation (NSF

Functional network changes and cognitive control in schizophrenia

Cognitive control is a cognitive and neural mechanism that contributes to managing the complex demands of day-to-day life. Studies have suggested that functional impairments in cognitive control associated brain circuitry contribute to a broad range of higher cognitive deficits in schizophrenia. To examine this issue, we assessed functional connectivity networks in healthy adults and individuals with schizophrenia performing tasks from two distinct cognitive domains that varied in demands for cognitive control, the RiSE episodic memory task and DPX goal maintenance task. We characterized general and cognitive control-specific effects of schizophrenia on functional connectivity within an expanded frontal parietal network (FPN) and quantified network topology properties using graph analysis. Using the network based statistic (NBS), we observed greater network functional connectivity in cognitive control demanding conditions during both tasks in both groups in the FPN, and demonstrated cognitive control FPN specificity against a task independent auditory network. NBS analyses also revealed widespread connectivity deficits in schizophrenia patients across all tasks. Furthermore, quantitative changes in network topology associated with diagnostic status and task demand were observed. The present findings, in an analysis that was limited to correct trials only, ensuring that subjects are on task, provide critical insights into network connections crucial for cognitive control and the manner in which brain networks reorganize to support such control. Impairments in this mechanism are present in schizophrenia and these results highlight how cognitive control deficits contribute to the pathophysiology of this illness

Public perceptions of cancer: a qualitative study of the balance of positive and negative beliefs

Objectives: Cancer's insidious onset and potentially devastating outcomes have made it one of the most feared diseases of the 20th century. However, advances in early diagnosis and treatment mean that death rates are declining, and there are more than 30 million cancer survivors worldwide. This might be expected to result in more sanguine attitudes to the disease. The present study used a qualitative methodology to provide an in-depth exploration of attitudes to cancer and describes the balance of negative and positive perspectives. Design: A qualitative study using semistructured interviews with thematic analysis. Setting: A university in London, UK. Participants: 30 participants (23–73 years), never themselves diagnosed with cancer. Results: Accounts of cancer consistently incorporated negative and positive views. In almost all respondents, the first response identified fear, trauma or death. However, this was followed—sometimes within the same sentence—by acknowledgement that improvements in treatment mean that many patients can survive cancer and may even resume a normal life. Some respondents spontaneously reflected on the contradictions, describing their first response as a ‘gut feeling’ and the second as a more rational appraisal—albeit one they struggled to believe. Others switched perspective without apparent awareness. Conclusions: People appear to be ‘in two minds’ about cancer. A rapid, intuitive sense of dread and imminent death coexists with a deliberative, rational recognition that cancer can be a manageable, or even curable, disease. Recognising cancer's public image could help in the design of effective cancer control messages

How bias correction goes wrong: measurement of X_(CO_2) affected by erroneous surface pressure estimates

All measurements of X_(CO_2) from space have systematic errors. To reduce a large fraction of these errors, a bias correction is applied to X_(CO_2) retrieved from GOSAT and OCO-2 spectra using the ACOS retrieval algorithm. The bias correction uses, among other parameters, the surface pressure difference between the retrieval and the meteorological reanalysis. Relative errors in the surface pressure estimates, however, propagate nearly 1:1 into relative errors in bias-corrected X_(CO_2). For OCO-2, small errors in the knowledge of the pointing of the observatory (up to ∼130 arcsec) introduce a bias in X_(CO_2) in regions with rough topography. Erroneous surface pressure estimates are also caused by a coding error in ACOS version 8, sampling meteorological analyses at wrong times (up to 3 h after the overpass time). Here, we derive new geolocations for OCO-2's eight footprints and show how using improved knowledge of surface pressure estimates in the bias correction reduces errors in OCO-2's v9 X_(CO_2) data

Variability in the immune response to Theiler's Murine Encephalomyelitis Virus in different strains of mice

Theiler's Murine Encephalomyelitis Virus (TMEV) has been a favoured model for Multiple Sclerosis (MS) since 1975 when Lipton first reported that infection with TMEV caused a biphasic Central Nervous System (CNS) disease leading to demyelination. TMEV is a picornavirus belonging to the cardiovirus genus and is a natural enteric pathogen of mice which can occasionally initiate a chronic persistent infection of the CNS. This depends on the strain and dose of virus and the strain, age and sex of the mouse. Intracerebral infection of all mouse strains with the avirulent BeAn strain of TMEV results in an acute encephalomyelitis which in susceptible mouse strains, is followed by a persistent CNS infection with lesions of inflammatory demyelination or in resistant mouse strains eradication of the virus. On the other hand i.e. infection with the neurovirulent GDVII strain of Theiler's virus results in a fulminant encephalitis in mice of all genetic backgrounds.The main aim of this study was to determine the cytokine and immunoglobulin profiles elicited in different mouse strains during the acute phase of infection. mRNA transcript levels for numerous cytokines were studied in the brains and spinal cords in Balb/c (resistant), CBA (intermediately susceptibility) and SJL/J (susceptible) mice, during the acute phase of disease, using the technique of RNase protection assay (RPA). The RPA included analysis of transcripts for TNFp, TNFa, TGFp, IFNy, IL-la, ILip, IL-2, IL-4, IL-5, IL-6, IL-7, IL-10, IL-13, IL-12p40 and IL-12p35. There were similarities between the strains in the levels of pro-inflammatory cytokines expressed including TNFa, TNFp and ILla. However, there were several fundamental differences between the strains including the inability of susceptible SJL/J mice to express IL-ip in the brain and the spinal cord when compared to Balb/c and CBA mice. SJL/J mice had an increase in expression of IL-4 and IL-10 and a decrease in expression of IL-2 and IFNy when compared to Balb/c and CBA mice. Expression of pro-inflammatory, anti¬ inflammatory, Thl and Th2 type cytokines correlated with the increase in levels of cellular infiltrates (CD3+, CD4+, CD8+ and F4/80+) in the CNS. Anti¬ viral immunoglobulin isotypes were also different in the three mouse strains studied. All strains produced similar levels of IgM however, Balb/c mice had significantly increased levels of IgGl and IgG2a compared to CBA and SJL/J mice during the acute phase of disease.This study also investigated TMEV persistence in CBA (intermediately susceptible) mice and the cytokine and anti-viral immunoglobulin isotypes associated with persistence. Virus persisted for >60 days in 50% of infected CBA mice, as determined by RT-PCR. Animals in which virus persisted had significantly increased RNA transcripts in the CNS for TNFa, IL-12p35 and IL-12p40. Persistently infected animals also had increased levels of anti-viral IgGl, IgG2a and IgG2b when compared to animals which had cleared the virus.The importance of interferons a/p and y were investigated. Virus spread extensively throughout the white matter regions of the brains in IFNa/pR°/° mice (constructed on a genetically resistant background (FI-2b)), during the acute phase of infection, indicating the importance of IFNa/p in preventing infection of oligodendrocytes. Infection of IFNyR°/° mice (also on a genetically resistant background) resulted in viral persistence and increased levels of anti-viral IgM, IgGl, IgG2a and IgG2b, demonstrating IFNy is essential for viral clearance. Perforin is a functional effector molecule in CTL killing, therefore, its role(s) during the acute and chronic phase of Theiler's virus infection was investigated to ascertain its importance. Studies in perforin knockout mice (also on a resistant genetic background) demonstrated that perforin is essential to control viral infection during the acute phase of infection, and is an absolute requirement for viral clearance.Infection with GDVII resulted in high levels of virus replication in the brains and spinal cords of infected mice. Levels of TNFa, IL-la, IL-2, IFNy and IL- 12p40 increase throughout infection in the brains of infected animals, and TNFa, IL-2 and IL-12p40 increase in the spinal cords. High virus titres, and an increase in the above pro-inflammatory cytokines correlated with an increase in levels of programmed cell death in CNS tissues.Infection of neonatal mice with the BeAn strain results in 100% mortality, with increased virus titres in the CNS. Expression of TNFp, TNFa, IL-4, IL-la and IL-6 increased throughout the course of infection of neonatal mice. TNFa has been implicated in the phenomenon of death by shock. Therefore, TNFa may have important implications in the pathogenesis of Theiler's virus infection in neonates

Using market-based indicators to assess banking system resilience

This report reviews the use of quantitative tools to gauge market participants’ assessment of banking system resilience. These measures complement traditional balance-sheet metrics and suggest that markets consider large Canadian banks to be better placed to weather adverse shocks than banks in other advanced economies. Compared with regulatory capital ratios, however, the measures suggest less improvement in banking system resilience since the pre-crisis period