Data base on animal mortality

A data base on animal mortality has been compiled. The literature on LD/sub 50/ and the dose-response function for radiation-induced lethality, reflect several inconsistencies - primarily due to dose assignments and to analytical methods and/or mathematical models used. Thus, in order to make the individual experiments which were included in the data base as consistent as possible, an estimate of the uniform dose received by the bone marrow in each treatment group was made so that the interspecies differences are minimized. The LD/sub 50/ was recalculated using a single estimation procedure for all studies for which sufficient experimental data are available. For small animals such as mice, the dose to the hematopoietic system is approximately equal to the treatment dose, but for large animals the marrow dose may be about half of the treatment dose

The response of low-latitude calcareous phytoplankton to global change through the Eocene-Oligocene transition.

This thesis documents the response of calcareous phytoplankton assemblages to major changes in global climate during the Eocene-Oligocene transition (EOT) at three low-latitude sites Tanzanian Drilling Project (TDP) Sites 12 & 17 (southern coastal Tanzania), Deep Sea Drilling Site 242 (Mozambique Channel, western Indian Ocean) and St Stephens Quarry (Alabama, USA). High-resolution nannofossil count data from all three study sites clearly indicate a major change in coccolithophore assemblage compositions directly coincident with the first step change in the positive oxygen isotope (d180) shift into the early Oligocene Glacial Maximum (EOGM). This is followed by continued shifts in coccolithophore assemblages in the vicinity of the Eocene-Oligocene boundary to reach new "Oligocene" assemblage compositions before the second step in duO and peak glacial conditions of the EOGM. At all sites there is a marked increase in the abundance of Cyclicargolithus floridanus (>5um) and to a lesser extent Sphenolithus predistentus, combined with a general loss of warm-water and oligotrophic taxa including Calcidiscus protoannulus, discoaster and holococcolith species. This consistent pattern of biotic change, from sites with varying species compositions and preservation states, indicates a large and geographically widespread perturbation in the low-latitude surface water environment and is consistent with new trace metal paleothermometry that indicates a significant, 2-3 C, cooling of surface waters in the earliest stages of the EOT. An exceptionally-well preserved and highly diverse nannofossil assemblage from late Eocene-early Oligocene (nannofossil zones NP19/20 to NP21 Martini 1971) sediments of coastal Tanzania is described and its implications for the Cenozoic history of the coccolithophores is discussed. This consists of a total of 114 species-equivalent morphotypes, one new genus (Pocillithus), six new species (Reticulofenestra macmillanii, Blackites culter, Rhabdosphaera suptilis, Orthozygus occultus, Orthozygus arms, Pocillithus spinulifer) and a previously unknown Paleogene deep-photic zone assemblage including representatives of the extant genera Gladiolithus, Algirosphaera and Acanthoica

ATCA radio detection of the new X-ray transient MAXI J1813-095 as a candidate radio-quiet black hole X-ray binary

We observed the new X-ray transient MAXI J1813-095 (ATels #11323, #11326, #11332) with the Australia Telescope Compact Array (ATCA) between 2018-02-22 20:52 UT and 2018-02-23 02:59 UT. Our observations were taken simultaneously at 5.5 and 9 GHz, with a bandwidth of 2 GHz at each frequency

Bi flux-dependent MBE growth of GaSbBi alloys

AbstractThe incorporation of Bi in GaSb1−xBix alloys grown by molecular beam epitaxy is investigated as a function of Bi flux at fixed growth temperature (275°C) and growth rate (1μmh−1). The Bi content is found to vary proportionally with Bi flux with Bi contents, as measured by Rutherford backscattering, in the range 0<x≤4.5%. The GaSbBi samples grown at the lowest Bi fluxes have smooth surfaces free of metallic droplets. The higher Bi flux samples have surface Bi droplets. The room temperature band gap of the GaSbBi epitaxial layers determined from optical absorption decreases linearly with increasing Bi content with a reduction of ~32meV/%Bi