SOFIA mid-infrared observations of Supernova 1987A in 2016 - Forward shocks and possible dust re-formation in the post-shocked region

The equatorial ring of Supernova (SN) 1987A has been exposed to forward shocks from the SN blast wave, and it has been suggested that these forward shocks have been causing ongoing destruction of dust in the ring.We obtained Stratospheric Observatory For Infrared Astronomy The Faint Object InfraRed CAmera for the SOFIA Telescope (FORCAST) 11.1, 19.7, and 31.5 μmphotometry of SN 1987A in 2016. Compared with Spitzer measurements 10 yr earlier, the 31.5 μm flux has significantly increased. The excess at 31.5 μm appears to be related to the Herschel 70 μm excess, which was detected 5 yr earlier. The dust mass needed to account for the 31.5-70 μm excess is 3-7 × 10-4M⊙, more than 10 times larger than the ring dust mass (~1 × 10-5M⊙) estimate from the data 10 yr earlier. We argue that dust grains are re-formed or grown in the post-shock regions in the ring after forward shocks have destroyed pre-existing dust grains in the ring and released refractory elements into gas. In the post-shock region, atoms can stick to surviving dust grains, and the dust mass may have increased (grain growth), or dust grains might have condensed directly from the gas. An alternative possibility is that the outer part of the expanding ejecta dust might have been heated by X-ray emission from the circumstellar ring. The future development of this excess could reveal whether grains are reformed in the post-shocked region of the ring or eject dust is heated by X-ray

Galactic and Extragalactic Samples of Supernova Remnants: How They Are Identified and What They Tell Us

Supernova remnants (SNRs) arise from the interaction between the ejecta of a supernova (SN) explosion and the surrounding circumstellar and interstellar medium. Some SNRs, mostly nearby SNRs, can be studied in great detail. However, to understand SNRs as a whole, large samples of SNRs must be assembled and studied. Here, we describe the radio, optical, and X-ray techniques which have been used to identify and characterize almost 300 Galactic SNRs and more than 1200 extragalactic SNRs. We then discuss which types of SNRs are being found and which are not. We examine the degree to which the luminosity functions, surface-brightness distributions and multi-wavelength comparisons of the samples can be interpreted to determine the class properties of SNRs and describe efforts to establish the type of SN explosion associated with a SNR. We conclude that in order to better understand the class properties of SNRs, it is more important to study (and obtain additional data on) the SNRs in galaxies with extant samples at multiple wavelength bands than it is to obtain samples of SNRs in other galaxiesComment: Final 2016 draft of a chapter in "Handbook of Supernovae" edited by Athem W. Alsabti and Paul Murdin. Final version available at https://doi.org/10.1007/978-3-319-20794-0_90-

Influenza vaccination for immunocompromised patients: systematic review and meta-analysis from a public health policy perspective.

Immunocompromised patients are vulnerable to severe or complicated influenza infection. Vaccination is widely recommended for this group. This systematic review and meta-analysis assesses influenza vaccination for immunocompromised patients in terms of preventing influenza-like illness and laboratory confirmed influenza, serological response and adverse events

Production of dust by massive stars at high redshift

The large amounts of dust detected in sub-millimeter galaxies and quasars at high redshift pose a challenge to galaxy formation models and theories of cosmic dust formation. At z > 6 only stars of relatively high mass (> 3 Msun) are sufficiently short-lived to be potential stellar sources of dust. This review is devoted to identifying and quantifying the most important stellar channels of rapid dust formation. We ascertain the dust production efficiency of stars in the mass range 3-40 Msun using both observed and theoretical dust yields of evolved massive stars and supernovae (SNe) and provide analytical expressions for the dust production efficiencies in various scenarios. We also address the strong sensitivity of the total dust productivity to the initial mass function. From simple considerations, we find that, in the early Universe, high-mass (> 3 Msun) asymptotic giant branch stars can only be dominant dust producers if SNe generate <~ 3 x 10^-3 Msun of dust whereas SNe prevail if they are more efficient. We address the challenges in inferring dust masses and star-formation rates from observations of high-redshift galaxies. We conclude that significant SN dust production at high redshift is likely required to reproduce current dust mass estimates, possibly coupled with rapid dust grain growth in the interstellar medium.Comment: 72 pages, 9 figures, 5 tables; to be published in The Astronomy and Astrophysics Revie

The Shackles of Practice: History of psychology, research assessment and the curriculum

The history of psychology is being increasingly marginalized in British universities. In this article we argue that this marginalization has been brought about by a combination of material circumstances resulting from the marketization of the UK Higher Education sector. One consequence of this, the statutory audit known as the Research Excellence Framework, has made it increasingly difficult to undertake historical work as it has traditionally been done in UK Psychology Departments. At best such a situation challenges the ambition for historical work to have an impact on psychology. At worst it potentially renders the history of psychology irrelevant. Yet the theoretical justification for history of psychology has never been stronger. Psychology’s subject matter is neither exclusively natural nor entirely socially constructed, but lies on that “somewhat suspect borderland between physiology and philosophy” as Wilhelm Wundt put it. The discipline’s ontological claims are therefore always made from within epistemological frameworks which are themselves products of particular historical contexts. Such arguments have persuaded us that history of psychology has a fundamental role to play within the wider discipline. Yet as historians we cannot ignore the constraining social and material circumstances in which our field operates. We conclude that although the constraints of practice suggest that its prospects for influencing its parent discipline are seriously challenged, there are nevertheless opportunities for the history of psychology areas such as the undergraduate curriculum

Existence, uniqueness and some comparative statics for ratio and Lindahl equilibria

Public goods, Lindahl equilibrium, Ratio equilibrium, H41,