Evolution and ecology of influenza A viruses.

Cosmochemistry of the rare earth elements: meteorite studies.

▪ Abstract At luminosities above 1011 , infrared galaxies become the dominant population of extragalactic objects in the local Universe (z ≲ 0.3), being more numerous than optically selected starburst and Seyfert galaxies and quasi-stellar objects at comparable bolometric luminosity. The trigger for the intense infrared emission appears to be the strong interaction/merger of molecular gas-rich spirals, and the bulk of the infrared luminosity for all but the most luminous objects is due to dust heating from an intense starburst within giant molecular clouds. At the highest luminosities (Lir > 1012 ), nearly all objects appear to be advanced mergers powered by a mixture of circumnuclear starburst and active galactic nucleus energy sources, both of which are fueled by an enormous concentration of molecular gas that has been funneled into the merger nucleus. These ultraluminous infrared galaxies may represent an important stage in the formation of quasi-stellar objects and powerful radio galaxies. They may al...

/pdf/luminous-infrared-galaxies-zoi3y3hutv.pdf

Luminous infrared galaxies

We construct size distributions for carbonaceous and silicate grain populations in different regions of the Milky Way, LMC, and SMC. The size distributions include sufficient very small carbonaceous grains (including polycyclic aromatic hydrocarbon molecules) to account for the observed infrared and microwave emission from the diffuse interstellar medium. Our distributions reproduce the observed extinction of starlight, which varies depending on the interstellar environment through which the light travels. As shown by Cardelli, Clayton, and Mathis in 1989, these variations can be roughly parameterized by the ratio of visual extinction to reddening, RV. We adopt a fairly simple functional form for the size distribution, characterized by several parameters. We tabulate these parameters for various combinations of values for RV and bC, the C abundance in very small grains. We also find size distributions for the line of sight to HD 210121 and for sight lines in the LMC and SMC. For several size distributions, we evaluate the albedo and scattering asymmetry parameter and present model extinction curves extending beyond the Lyman limit.

https://iopscience.iop.org/article/10.1086/318651/pdf

Dust Grain-Size Distributions and Extinction in the Milky Way, Large Magellanic Cloud, and Small Magellanic Cloud

▪ Abstract This review surveys the observed properties of interstellar dust grains: the wavelength-dependent extinction of starlight, including absorption features, from UV to infrared; optical lum...

https://www.ifa.hawaii.edu/users/reipurth/reviews/draine.pdf

Interstellar dust grains

Samples of air removed from the stratosphere, at an altitude of 41 km, were previously found to contain viable, but non-cultureable bacteria (cocci and rods). Here, we describe experiments aimed at growing these, together with any other organisms, present in these samples. Two bacteria (Bacillus simplex and Staphylococcus pasteuri) and a single fungus, Engyodontium album (Limber) de Hoog were isolated from the samples. Although the possibility of contamination can never be ruled out when space-derived samples are studied on earth, we are confident that the organisms originated from the stratosphere. Possible mechanisms by which these organisms could have attained such a height are discussed.

http://miltonwainwright.com/wp-content/uploads/2015/06/Wainwright-2003-Microorganisms-cultured-from-s.pdf

Microorganisms cultured from stratospheric air samples obtained at 41 km.

/pdf/on-graphite-particles-as-interstellar-grains-53frsmswln.pdf

On Graphite Particles as Interstellar Grains

Light Scattering Functions for Small particles with applications in Astronomy

THERE is now considerable evidence to support the view that supernovae can be caused by the explosive ignition of degenerate material in evolved stars1. The conditions leading to such ignition have recently been investigated by Arnett (ref. 2 and private communication). Explosive carbon-burning produces elements ranging from Ne to Si, and silicon-burning produces elements from P to Ni. The relative abundances of elements produced in both processes are similar to the observed solar values, which supports the view that supernova explosions are a major source of enrichment of the interstellar medium in heavy elements.

Dust in supernova explosions.

We discuss evidence to show that the generally accepted view of the Big Bang model for the origin of the Universe is unsatisfactory. We suggest an alternative model that satisfies the constraints better.

N. C. Wickramasinghe

Papers

Microorganisms cultured from stratospheric air samples obtained at 41 km.

On Graphite Particles as Interstellar Grains

Light Scattering Functions for Small particles with applications in Astronomy

Dust in supernova explosions.

The extragalactic universe - An alternative view