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A comparative cohort study of people transfered from prison to hospital under the Mental Health Act (1983)
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NGC 4370: a case study for testing our ability to infer dust distribution and mass in nearby galaxies
No full textContext. A segment of the early-type galaxy population hosts a prominent dust lane, often decoupled from its stellar body. Methods of quantifying the dust content of these systems based on optical imaging data usually yield dust masses that are an order of magnitude lower than dust masses derived from the observed far-IR (FIR) emission. The discrepancy is often explained by invoking a diffuse dust component that is hard to trace in the UV or optical. Aims. High-quality optical data from the Next Generation Virgo cluster Survey (NGVS) and FIR/sub-mm observations from the Herschel Virgo Cluster Survey (HeViCS) allow us to revisit previous methods of determining the dust content in galaxies and explore new ones. NGC 4370 is an edge-on, early-type galaxy with a conspicuous dust lane and regular morphology, making it suitable for several (semi-)analytical modelling techniques. We aim to derive the dust mass from both optical and FIR data and to investigate the need to invoke a putative diffuse dust component. Methods. We used different methods to determine the total dust mass in the dust lane. We used our exquisite optical data to create colour and attenuation maps, which are converted to approximate dust mass maps based on simple dust geometries. Dust masses were also derived from SED fits to FIR to sub-mm observations. Finally, inverse radiative transfer fitting was performed to investigate more complex dust geometries, such as an exponential dust disc and a dust ring and to treat the dust-starlight interaction in a self-consistent way. Results. We find that the empirical methods applied to the optical data yield lower limits of 3.4 × 105 M⊙, an order of magnitude below the total dust masses derived from SED fitting. In contrast, radiative transfer models yield dust masses that are slightly lower, but fully consistent with the FIR-derived mass. We find that the effect of a nuclear stellar disc on the derivation of the total dust mass is minor. Conclusions. Dust is more likely to be distributed in a ring around the centre of NGC 4370 as opposed to an exponential disc or a simple foreground screen. Moreover, by using inverse radiative transfer fitting, we are able to constrain most of the parameters that describe these geometries. The resulting dust masses are high enough to account for the dust observed at FIR/sub-mm wavelengths, so that no diffuse dust component needs to be invoked. We furthermore caution against interpreting dust masses and optical depths based on optical data alone, when using overly simplistic star-dust geometries and the neglect of scattering effects
Dynamics of Wolbachia pipientis gene expression across the Drosophila melanogaster life cycle.
No full textThe Varian story
No full textThis Perspective offers a personal view of the story of Varian NMR, a courageous initiative that began in the 1950s but came to an abrupt end some 60 years later. Without doubt, Varian leaves behind a priceless legacy, particularly in the field of structural chemistry. The highlights are set out in four main sections, named after the four seasons, but not necessarily in strict chronology. How did the accepted business practices influence the evolution, growth, and eventual demise of this exciting venture? How well did management handle an unconventional group of young scientific entrepreneurs? What does it all mean for the future of magnetic resonance? The subject can be viewed on two different levels, the Varian story itself, and the larger picture - the Silicon Valley phenomenon as a whole, with Varian considered as an interesting microcosm. (C) 2014 Elsevier Inc. All rights reserved
Multiscale analysis of the gradient of linear polarization
No full textWe propose a new multiscale method to calculate the amplitude of the gradient of the linear polarization vector, |∇ P|, using a wavelet-based formalism. We demonstrate this method using a field of the Canadian Galactic Plane Survey and show that the filamentary structure typically seen in |∇ P| maps depends strongly on the instrumental resolution. Our analysis reveals that different networks of filaments are present on different angular scales. The wavelet formalism allows us to calculate the power spectrum of the fluctuations seen in |∇ P and to determine the scaling behaviour of this quantity. The power spectrum is found to follow a power law with γ ≈ 2.1. We identify a small drop in power between scales of 80 ≲ l ≲ 300 arcmin, which corresponds well to the overlap in the u-v plane between the Effelsberg 100-m telescope and the Dominion Radio Astrophysical Observatory 26-m telescope data. We suggest that this drop is due to undersampling present in the 26-m telescope data. In addition, the wavelet coefficient distributions show higher skewness on smaller scales than at larger scales. The spatial distribution of the outliers in the tails of these distributions creates a coherent subset of filaments correlated across multiple scales, which trace the sharpest changes in the polarization vector P within the field. We suggest that these structures may be associated with highly compressive shocks in the medium. The power spectrum of the field excluding these outliers shows a steeper power law with γ ≈ 2.5
Long Term Study of the Double Pulsar J0737-3039 with XMM-Newton: pulsar timing
No full textThe relativistic double neutron star binary PSR J0737-3039 shows clear evidence of orbital phase-dependent wind-companion interaction, both in radio and X-rays. In this paper we present the results of timing analysis of PSR J0737-3039 performed during 2006 and 2011 XMM-Newton Large Programs that collected 20,000 X-ray counts from the system. We detected pulsations from PSR J0737-3039A (PSR A) through the most accurate timing measurement obtained by XMM-Newton so far, the spin period error being of 2x10^-13 s. PSR A's pulse profile in X-rays is very stable despite significant relativistic spin precession that occurred within the time span of observations. This yields a constraint on the misalignment between the spin axis and the orbital momentum axis Delta_A 6.6^+1.3_-5.4 deg, consistent with estimates based on radio data. We confirmed pulsed emission from PSR J0737-3039B (PSR B) in X-rays even after its disappearance in radio. The unusual phenomenology of PSR B's X-ray emission includes orbital pulsed flux and profile variations as well as a loss of pulsar phase coherence on time scales of years. We hypothesize that this is due to the interaction of PSR A's wind with PSR B's magnetosphere and orbital-dependent penetration of the wind plasma onto PSR B closed field lines. Finally, the analysis of the full XMM-Newton dataset provided evidences of orbital flux variability ( 7%) for the first time, involving a bow-shock scenario between PSR A's wind and PSR B's magnetosphere
Causal and mediating factors for anxiety, depression and well-being.
No full textBackground The relationship between well-being and mental ill health is complex; people may experience very low levels of well-being even in the absence of overt mental health problems. Aims This study tested the hypothesis that anxiety, depression and well-being have different causal determinants and psychological mediating mechanisms. Method The influence of causal and mediating factors on anxiety, depression and well-being were investigated in a cross-sectional online questionnaire survey hosted on a UK national broadcasting website. Results Multivariate conditional independence analysis of data from 27 397 participants revealed different association pathways for the two constructs. Anxiety and depression were associated with negative life events mediated by rumination; low levels of subjective well-being were associated with material deprivation and social isolation, mediated by adaptive coping style. Conclusions Our findings support the 'two continua' model of the relationship between psychological well-being and mental health problems, with implications for both treatment and prevention
