Deep Submillimeter Surveys: Luminous Infrared Galaxies at High Redshift

Deep surveys at 850microns from Mauna Kea using the SCUBA camera on the JCMT appear to have discovered a substantial population of ultraluminous infrared galaxies (ULIGs: L_ir > 10^{12} L_sun). The cumulative space density of these sources (~10,000 per sq.deg with S_850 > 1mJy) is sufficient to account for nearly all of the extragalactic background light at submillimeter wavelengths. Current estimates of the redshift distribution suggest a peak in the comoving space density of SCUBA sources at z = 1-3, similar to what is observed for QSOs and radio galaxies. The luminosity density in the far-infrared/submillimeter exceeds that in the UV by factors of 3-10 over this redshift range, implying that as much as 80-90% of the "activity" in galaxies at z < 4 is hidden by dust. The SCUBA sources plausibly represent the primary epoch in the formation of spheroids and massive black holes triggered by major mergers of large gas-rich disks.Comment: LaTex, 14 pages with 9 embedded .eps figures. To appear in ``Space Infrared Telescopes and Related Science", 32nd COSPAR workshop, Nagoya, Japan 1998, ed. T. Matsumoto, T. de Graau

Form factors in lattice QCD

Lattice simulations of QCD have produced precise estimates for the masses of the lowest-lying hadrons which show excellent agreement with experiment. By contrast, lattice results for the vector and axial vector form factors of the nucleon show significant deviations from their experimental determination. We present results from our ongoing project to compute a variety of form factors with control over all systematic uncertainties. In the case of the pion electromagnetic form factor we employ partially twisted boundary conditions to extract the pion charge radius directly from the linear slope of the form factor near vanishing momentum transfer. In the nucleon sector we focus specifically on the possible contamination from contributions of higher excited states. We argue that summed correlation functions offer the possibility of eliminating this source of systematic error. As an illustration of the method we discuss our results for the axial charge, gA, of the nucleon.Comment: 16 pages, 11 figures, presented at Conclusive Symposium, CRC443, "Many-body structure of strongly interacting systems", 23-25 Feb 2011, Mainz, German

Factors influencing terrestriality in primates of the Americas and Madagascar

Among mammals, the order Primates is exceptional in having a high taxonomic richness in which the taxa are arboreal, semiterrestrial, or terrestrial. Although habitual terrestriality is pervasive among the apes and African and Asian monkeys (catarrhines), it is largely absent among monkeys of the Americas (platyrrhines), as well as galagos, lemurs, and lorises (strepsirrhines), which are mostly arboreal. Numerous ecological drivers and species-specific factors are suggested to set the conditions for an evolutionary shift from arboreality to terrestriality, and current environmental conditions may provide analogous scenarios to those transitional periods. Therefore, we investigated predominantly arboreal, diurnal primate genera from the Americas and Madagascar that lack fully terrestrial taxa, to determine whether ecological drivers (habitat canopy cover, predation risk, maximum temperature, precipitation, primate species richness, human population density, and distance to roads) or species-specific traits (body mass, group size, and degree of frugivory) associate with increased terrestriality. We collated 150,961 observation hours across 2,227 months from 47 species at 20 sites in Madagascar and 48 sites in the Americas. Multiple factors were associated with ground use in these otherwise arboreal species, including increased temperature, a decrease in canopy cover, a dietary shift away from frugivory, and larger group size. These factors mostly explain intraspecific differences in terrestriality. As humanity modifies habitats and causes climate change, our results suggest that species already inhabiting hot, sparsely canopied sites, and exhibiting more generalized diets, are more likely to shift toward greater ground use

Molecular characterization of Menangle Virus, a novel Paramyxovirus which infects pigs, fruit bats, and humans

Menangle virus (MenV), isolated in August 1997 following an outbreak of reproductive disease in a piggery in New South Wales, is the second previously unclassified member of the family Paramyxoviridae to be identified in Australia since 1994. Similar to Hendra virus (HeV), MenV appears to be a virus of fruit bats (flying foxes) in the genus Pteropus. No serological cross-reactivity was detected between MenV and other known paramyxoviruses and to facilitate virus classification a cDNA subtraction method was used to obtain viral-specific cDNA from MenV-infected cells. Cloning and sequencing of the products enabled the entire sequences of the NP, P/V, M, F, and HN genes to be determined. Comparison of the nucleotide and deduced amino acid sequences for each gene with members of the family Paramyxoviridae, determination of the P gene mRNA editing strategy, and phylogenetic analyses confirmed that MenV is a new member of the genus Rubulavirus. However the deduced protein sequence of MenV HN exhibited only limited sequence homology when compared with attachment proteins of other paramyxoviruses. Key differences within the amino acid residues considered important determinants of neuraminidase activity suggest MenV HN is unlikely to possess the same degree of neuraminidase activity characteristic of other rubulavirus and respirovirus HN protein

Antigenic diversity and size diversity of P. falciparum antigens in isolates from Gambian patients. II. the schizont surface glycoprotein of molecular weight approximately 200 000.

A panel of monoclonal antibodies has been shown previously to identify both serologically diverse and serologically conserved epitopes on a major polymorphic surface protein of P. falciparum schizonts from culture-adapted isolates. The molecular nature of the antigen recognized by eight of these monoclonal antibodies was studied with three isolates analyzed directly from patients in The Gambia. Malarial (glyco) proteins were labelled by biosynthetic uptake of 3H-glucosamine or 3H-leucine during culture of ring-stage parasites from infected blood to the late-trophozoite/early-schizont stage (26-30 h). Those monoclonal antibodies which reacted positively with an isolate by indirect immunofluorescence also immunoprecipitated a single 3H-leucine or 3H-glucosamine labelled antigen of mol. wt approximately 200 000 from Triton X-100 extracts of the same isolate. Monoclonal antibodies which did not react by indirect immunofluorescence failed to immunoprecipitate this antigen. Although each of the three isolates studied in detail was very similar serologically with the panel of monoclonal antibodies specific for this mol. wt approximately 200 000 antigen, this protein could be distinguished with each isolate on the basis of its apparent size on SDS-polyacrylamide gel electrophoresis. The specifically immunoprecipitated antigen had a mol. wt of 204 000, 197 000 or 202 000, depending on the isolate. Size diversity of this malarial glycoprotein was also detected with seven other Gambian P. falciparum isolates. We conclude that natural isolates of P. falciparum express a major 3H-glucosamine labelled glycoprotein of mol. wt Mr approximately 200 000 which exhibits size diversity and expresses antigenically conserved as well as diverse epitopes as defined by the panel of monoclonal antibodies

Recombinant viral vaccines for enzootic bovine leucosis

Recently published studies on the development and use of recombinant vaccinia virus (VV) vaccines incorporating either the complete envelope (env) gene or only a fragment of the env gene consisting of the coding sequence for the env glycoprotein 51 (gp51) and part of gp30 of the bovine leukaemia virus (BLV) are described. It has been reported that vaccination of sheep with recombinant VV vaccines containing the complete env gene appears to protect sheep against challenge infection with BLV. The evidence for this protection is based on the lack of persistence of high titres of anti-gp51 antibodies compared with unvaccinated BLV infected controls, on the enhanced CD4 proliferative responses to specific BLV gp51 synthetic peptides in the vaccinated sheep, and on the inability to detect BLV pro-virus by polymerase chain reaction in the vaccinated sheep after 4 months following challenge infection compared with continual detection in unvaccinated sheep over a 16 month trial period. It has been suggested that cell-mediated immune responses may be an important aspect of protective immunity against BLV infection and it has been reported that large tracts of amino acid sequences within the env and pol genes are highly conserved in different isolates from different countries which is of importance in designing peptide derived vaccines

Capripoxviruses : an emerging worldwide threat to sheep, goats and cattle

Capripoxviruses are the cause of sheeppox, goatpox and lumpy skin disease (LSD) of cattle. These diseases are of great economic significance to farmers in regions in which they are endemic and are a major constraint to international trade in livestock and their products. Although the distribution of capripoxviruses is considerably reduced from what it was even 50 years ago, they are now expanding their territory, with recent outbreaks of sheeppox or goatpox in Vietnam, Mongolia and Greece, and outbreaks of LSD in Ethiopia, Egypt and Israel. Increased legal and illegal trade in live animals provides the potential for further spread, with, for instance, the possibility of LSD becoming firmly established in Asia. This review briefly summarizes what is known about capripoxviruses, including their impact on livestock production, their geographic range, host-specificity, clinical disease, transmission and genomics, and considers current developments in diagnostic tests and vaccines. Capripoxviruses have the potential to become emerging disease threats because of global climate change and changes in patterns of trade in animals and animal products. They also could be used as economic bioterrorism agents

Construction of recombinant fowlpox viruses carrying multiple vaccine antigens and immunomodulatory molecules

Here we describe plasmid vectors and selection protocols developed to allow the construction of recombinant fowlpox viruses (rFPVs) with up to three insertions of foreign DNA in the viral genome. Transient dominant selection allows the construction of recombinant viruses that do not retain the selection markers and can therefore be used for the insertion of additional genes at other sites in the viral genome. A SYBR® Green real-time PCR sequence detection assay was applied to the identification of recombinant viruses from individual plaques, eliminating the need for amplification and hybridization from the transient dominant protocol and resulting in significant savings in time at each round of plaque purification. Dominant selection techniques allow more rapid recombinant virus construction; however, as the markers are retained along with the gene of interest, they can only be used to generate the final recombinant. rFPV vaccines constructed using these techniques have reached preclinical nonhuman primate and phase I human clinical trials in prime/boost vaccination studies as human immunodeficiency virus (HIV) therapeutic and prophylactic vaccines

Self-consistency of electron-THF cross sections using electron swarm techniques

The drift velocity and first Townsend ionization coefficient of electrons in gaseous tetrahydrofuran are measured over the range of reduced electric fields 4-1000 Td using a pulsed-Townsend technique. The measured drift velocities and Townsend ionization coefficients are subsequently used, in conjunction with a multi-term Boltzmann equation analysis, as a further discriminative assessment on the accuracy and completeness of a recently proposed set of electron-THF vapor cross sections. In addition, the sensitivity of the transport coefficients to uncertainties in the existing cross sections is presented. As a result of that analysis, a refinement of the momentum transfer cross section for electron-THF scattering is presented, along with modifications to the neutral dissociation and dissociative electron attachment cross sections. With these changes to the cross section database, we find relatively good self-consistency between the measured and simulated drift velocities and Townsend coefficients