A Group of Red, Ly-alpha Emitting, High Redshift Galaxies

We have discovered two new high redshift (z=2.38) galaxies, near the previously known z=2.38 galaxy 2139-4434 B1 (Francis et al. 1996). All three galaxies are strong Ly-alpha emitters, and have much redder continuum colors (I-K about 5) than other optically-selected high redshift galaxies. We hypothesize that these three galaxies are QSO IIs; radio-quiet counterparts of high redshift radio galaxies, containing concealed QSO nuclei. The red colors are most easily modelled by an old (> 0.5 Gyr), massive (> 10E11 solar masses) stellar population. If true, this implies that at least one galaxy cluster of mass much greater than 3E11 solar masses had collapsed before redshift five.Comment: 12 pages, 2 figures, uses aaspp4 style file. Accepted for publication in Astrophysical Journal Letter

A Study of the Stellar Population in Selected SO Galaxies

The goal of this program was to observe at least two SO galaxies with abnormal colors in the blue and clear optical signatures of dust and gas. The galaxies NGC 2217 and NGC 1808 were observed at least in one of the IUE cameras (1200-200 and 2000-3200 A) during the 13th episode, using the 4 US1 shifts assigned to this program. The galaxy NGC 2217 had been found to be part of a subgroup of SO galaxies with external gas rotating in retrograde motion with respect to the stars. This galaxy is a face-on object with indications of large amount of gas, quite rare for a SO galaxy. We observed this object on three different occasions with IUE at different positions of the large aperture (spacecraft roll angle) with respect to the nuclear region. These exposures allowed us to take full advantage of the spatial resolution of IUE by mapping nuclear and bulge region of this galaxy. We found that the data point to a marginally earlier stellar population toward the central region. The UV light as a whole is dominated by a late-type stellar population of principally G and K stars. The almost face-on view of this galaxy appears optically thick to UV light. It is conceivable that in analogy to out own Galaxy, the stellar populations weakly detected in NGC 2217, are mostly halo and late-type stars in the center with an increasing contribution of dust and early stellar populations (so far undetected) as we move outward along the faint spiral arms. This result is contrary to our initial expectation, since the counterrotating gas does not appear to be enhancing star formation in this galaxy. Even more interesting were the observations of NGC 1808; galaxy which has been classified, with a handful of other objects, both as a starburst and Seyfert galaxy. Attachment: 'The White-Dwarf Companions of 56 Persei and HR 3643.

‘Cort short on a mountaintop’ – Eight new species of sequestrate Cortinarius from sub-alpine Australia and affinities to sections within the genus

During the course of research on mammal mycophagy and movement in the Northern Tablelands of New South Wales, Australia, extensive collections of sequestrate fungi were made, including numerous cortinarioid taxa. Historically any novel taxa would have been described in the cortinarioid sequestrate genera Descomyces, Hymenogaster, Protoglossum, Quadrispora, Thaxterogaster or Timgrovea based on broad morphological similarities of the sporocarps and spore ornamentation. However, consistent with other recent analyses of nuclear DNA regions, taxa from sequestrate genera were found to have affinities with Cortinarius and Descolea or Hebeloma, and to be scattered across many sections within Cortinarius. None of the historical sequestrate cortinarioid genera are monophyletic in our analyses. In particular, the gastroid genus Hymenogaster is paraphyletic, with one clade including two species of Protoglossum in Cortinarius, and a second clade sister to Hebeloma. Eight new species of sequestrate Cortinarius are described and illustrated, and discussion of their affinities with various sections provided: C. argyronius, C. caesibulga and C. cinereoroseolus in section Purpurascentes, C. maculobulga in section Rozites, C. sinapivelus in section Splendidi, C. kaputarensis in a mixed section Phlegmacium/Myxacium within a broader section Dermocybe, C. basorapulus in section Percomes and C. nebulobrunneus in section Pseudotriumphantes. Keys to genera of the Bolbitiaceae and Cortinariaceae containing sequestrate taxa and to currently known Australian species of sequestrate Cortinarius and Protoglossum are provided. As with the related agaricoid taxa, macroscopic characters such as colour and texture of basidioma, degree of loculisation of the hymenophore, and stipe-columella development and form remain useful for distinguishing species, but are generally not so useful at the sectional level within Cortinarius. Microscopic characters such as spore shape, size, and ornamentation, and pileipellis structure (simplex vs duplex and size of hyphal elements) are essential for determining species, and also appear to follow sectional boundaries

Reanalysis of Copernicus Measurements on Interstellar Carbon Monoxide

We used archival data acquired with the Copernicus satellite to reexamine CO column densities because self-consistent oscillator strengths are now available. Our focus is on lines of sight containing modest amounts of molecular species. Our resulting column densities are small enough that self-shielding from photodissociation is not occurring in the clouds probed by the observations. While our sample shows that the column densities of CO and H2 are related, no correspondence with the CH column density is evident. The case for the CH+ column density is less clear. Recent chemical models for these sight lines suggest that CH is mainly a by-product of CH+ synthesis in low density gas. The models are most successful in reproducing the amounts of CO in the densest sight lines. Thus, much of the CO absorption must arise from denser clumps along the line of sight to account for the trend with H2.Comment: 19 pages, 6 figures. Accepted for publication in Ap

High Velocity Line Emission in the NLR of NGC 4151

Narrow-band imaging of the nuclear region of NGC 4151 with the Hubble Space Telescope is presented. The filter bandpasses isolate line emission in various high velocity ranges in several ions. Slitless and long-slit spectra of the region with the Space Telescope Imaging Spectrograph also indicate the locations of high velocity gas. These emission regions are faint and are interspersed among the bright emission clouds seen in direct images. They have radial velocities up to 1400 km/s relative to the nucleus, and are found in both approach and recession on both sides of the nucleus. This contrasts strongly with the bright emission line clouds which have been discussed previously as showing bidirectional outflow with velocities within 400 km/s of the nucleus. We discuss the possible connections of the high velocity material with the radio jet and the nuclear radiation.Comment: 12 pages plus 6 figures, to be published in A

Physical conditions in CaFe interstellar clouds

Interstellar clouds that exhibit strong Ca I and Fe I lines were called CaFe clouds. The ionisation equilibrium equations were used to model the column densities of Ca II, Ca I, K I, Na I, Fe I and Ti II in CaFe clouds. The chemical composition of CaFe clouds is that of the Solar System and no depletion of elements onto dust grains is seen. The CaFe clouds have high electron densities n=1 cm^-3 that leads to high column densities of neutral Ca and Fe.Comment: Changed content, figure adde

Immunocytochemical demonstration of PTHrP protein in neoplastic tissue of HTLV-1 positive human adult T cell leukaemia/lymphoma: implications for the mechanism of hypercalcaemia.

The infiltrated tissues from seven West Indian patients with HTLV-1 positive adult T cell lymphoma/leukaemia (ATLL) have been analysed by immunocytochemical techniques for the presence of immunoreactive parathyroid hormone-related protein (PTHrP), a hormonal mediator of humoral hypercalcaemia of malignancy. Six of the seven were hypercalcaemic at some stage of the course of their disease. Four of the six evaluable patients showed evidence of specific cellular and extracellular expression of PTHrP protein in neoplastic tissues. This finding suggests that PTHrP may be involved in the production of hypercalcaemia in at least some cases of T cell lymphoma - proof of a causal relationship however must await the demonstration of tissue release of PTHrP resulting in raised circulating hormone levels

The evolution of plasticity of dauer larva developmental arrest in the nematode Caenorhabditis elegans.

Organisms can end up in unfavourable conditions and to survive this they have evolved various strategies. Some organisms, including nematodes, survive unfavourable conditions by undergoing developmental arrest. The model nematode Caenorhabditis elegans has a developmental choice between two larval forms, and it chooses to develop into the arrested dauer larva form in unfavourable conditions (specifically, a lack of food and high population density, indicated by the concentration of a pheromone). Wild C. elegans isolates vary extensively in their dauer larva arrest phenotypes, and this prompts the question of what selective pressures maintain such phenotypic diversity? To investigate this we grew C. elegans in four different environments, consisting of different combinations of cues that can induce dauer larva development: two combinations of food concentration (high and low) in the presence or absence of a dauer larva-inducing pheromone. Five generations of artificial selection of dauer larvae resulted in an overall increase in dauer larva formation in most selection regimes. The presence of pheromone in the environment selected for twice the number of dauer larvae, compared with environments not containing pheromone. Further, only a high food concentration environment containing pheromone increased the plasticity of dauer larva formation. These evolutionary responses also affected the timing of the worms' reproduction. Overall, these results give an insight into the environments that can select for different plasticities of C. elegans dauer larva arrest phenotypes, suggesting that different combinations of environmental cues can select for the diversity of phenotypically plastic responses seen in C. elegans.We would like to thank Henrique Teotonio for the gift of the G140.A population, Louise Hughes and Laura Weldon for technical help, two anonymous reviewers for their comments, and NERC for funding.This is the final published version of the article. It was originally published in Ecology and Evolution (Diaz SA, Viney M, Ecology and Evolution 2015, 5(6), 1343–1353, doi:10.1002/ece3.1436) http://dx.doi.org/10.1002/ece3.143

Superflares on Ordinary Solar-Type Stars

Short duration flares are well known to occur on cool main-sequence stars as well as on many types of `exotic' stars. Ordinary main-sequence stars are usually pictured as being static on time scales of millions or billions of years. Our sun has occasional flares involving up to $\sim 10^{31}$ ergs which produce optical brightenings too small in amplitude to be detected in disk-integrated brightness. However, we identify nine cases of superflares involving $10^{33}$ to $10^{38}$ ergs on normal solar-type stars. That is, these stars are on or near the main-sequence, are of spectral class from F8 to G8, are single (or in very wide binaries), are not rapid rotators, and are not exceedingly young in age. This class of stars includes many those recently discovered to have planets as well as our own Sun, and the consequences for any life on surrounding planets could be profound. For the case of the Sun, historical records suggest that no superflares have occurred in the last two millennia.Comment: 16 pages, accepted for publication in Ap