Primordial Black Holes, Hawking Radiation and the Early Universe

The 511 keV gamma emission from the galactic core may originate from a high concentration ($\sim 10^{22}$) of primordial black holes (PBHs) in the core each of whose Hawking radiation includes $\sim 10^{21}$ positrons per second. The PBHs we consider are taken as near the lightest with longevity greater than the age of the universe (mass $\sim 10^{12}$ kg; Schwarzschild radius $\sim 1$ fm). These PBHs contribute only a small fraction of cold dark matter, $\Omega_{PBH} \sim 10^{-8}$. This speculative hypothesis, if confirmed implies the simultaneous discovery of Hawking radiation and an early universe phase transition.Comment: 4 Page

MeV Dark Matter: Has It Been Detected?

We discuss the possibility that the recent detection of 511 keV gamma-rays from the galactic bulge, as observed by INTEGRAL, is a consequence of low mass (~MeV) particle dark matter annihilations. We discuss the type of halo profile favored by the observations as well as the size of the annihilation cross section needed to account for the signal. We find that such a scenario is consistent with the observed dark matter relic density and other constraints from astrophysics and particle physics.Comment: 4 pages, 1 figur

Fate and Persistence of Crude Oil Stranded on a Sheltered Beach

Detailed observations, mapping and sampling were conducted following an experimental spill of 15 cu m of crude oil adjacent to the coast at Cape Hatt, Baffin Island, N.W.T. The beach could not retain all of the oil that reached the shoreline, and as a result, one-third of the spill oil was recovered in cleanup activities on the water, approximately one-third was lost to the atmosphere and to the ocean and one-third remained stranded on the intertidal zone. The stranded oil was subject to natural cleaning processes during approximately 6 months of open-water periods from 1981 to 1983. Over this period the surface area of oil cover was reduced by approximately half, whereas estimates indicate that 80% of the oil initially stranded (5.3 cu m) was removed. This natural removal of stranded oil occurred in a very sheltered environment. The reduction of the surface area and of the volume of oil resulted primarily from the physical processes associated with wave activity and ground-water leaching. By 1983 an asphalt pavement had developed in the upper intertidal zone on the beach-face slope. Total hydrocarbon concentrations of samples collected from the asphalt pavement indicated a significant increase in oil-in-sediment values in this zone to concentrations in the order of 2-5%. Oil removed from the beach was transported into the adjacent nearshore bottom sediments, where oil concentrations increased sixfold between 1981 and 1983. Physio-chemical weathering rates were relatively rapid immediately following the release of the oil, as the lower molecular weight (C1 to C10) hydrocarbons evaporated. Subsequent physio-chemical changes were heterogeneous .... The primary conclusion from the investigations undertaken to date is that oil is removed in substantial quantities from the intertidal zone even in such a sheltered, low-energy arctic environment. Similar changes should also be expected from comparable environments in lower latitudes.Key words: oil spill, natural oil weathering, asphalt pavement, beached oilMots clés: déversement de pétrole, dégradation naturelle du pétrole, plaque d’asphalte, pétrole échou&eacute

Co-culture of Yeast Antagonists of Fusarium Head Blight and their Effect on Disease Development in Wheat

Multistrain mixtures of biocontrol agents which can reduce plant disease to a greater extent than the individual strains of the mixture, commonly, are prepared by blending separately produced fermentation products. Co-cultivation of strains to equivalent biomass yields would provide mixture advantages without incurring the cost disadvantages of multiple fermentation and processing protocols. Fusariwn Head Blight (FHB) antagonists Cryptococcus flavescens OR 182.9 (NRRL Y-302l6), C. aureus OH 181.1 (NRRL Y-302l5) and C. aureus OR 181.1 (NRRL Y -30215), were grown in two- and three-strain co-cultures to assess the quality and efficacy of the fermentation end products produced. Final cell counts of component strains of all co-cultures produced were equivalent when plated on a medilllll that contained the trisaccharide melezitose as a sole carbon source and produced colonies of strain-distinguishable sizes. Co-cultures of C. flavescens OH 182.9 and C. aureus OH 71.4 significantly reduced FHB disease severity (32%, p = 0.05, Dunnett\u27s t-test) when averaged across four greenhouse studies. In wheat field trials, biomass from co-cultures of these two strains reduced FHB incidence in some cases but rarely other FHB disease parameters (p = 0.05, Bonferoni mean separation). Relative Performance Index (RPI) analysis of the overall effect of treatments at both field sites revealed that treatment with the OH 71.4 and OH 182.9 co-culture significantly reduced FHB, as evidence by a higher RPI value than for the control, while the individual strains did not. The potential for obtaining superior efficacy and cost benefits with multi-strain cultures of biocontrol agents justifies additional research effort

Orion Multi-Purpose Crew Vehicle Active Thermal Control and Environmental Control and Life Support Development Status

The Orion Multi Purpose Crew Vehicle (MPCV) is the first crew transport vehicle to be developed by the National Aeronautics and Space Administration (NASA) in the last thirty years. Orion is currently being developed to transport the crew safely beyond Earth orbit. This year, the vehicle focused on building the Exploration Flight Test 1 (EFT1) vehicle to be launched in September of 2014. The development of the Orion Active Thermal Control (ATCS) and Environmental Control and Life Support (ECLS) System, focused on the integrating the components into the EFT1 vehicle and preparing them for launch. Work also has started on preliminary design reviews for the manned vehicle. Additional development work is underway to keep the remaining component progressing towards implementation on the flight tests of EM1 in 2017 and of EM2 in 2020. This paper covers the Orion ECLS development from April 2013 to April 2014

Hydrocarbon Biogeochemical Setting of the Baffin Island Oil Spill Experimental Sites. I. Sediments

A baseline for petroleum residues in the sediments of the Cape Hatt Island in arctic Canada was obtained in anticipation of controlled oil releases of the Baffin Island Oil Spill (BIOS) Project. In subtidal sediments, the existing background of petroleum residues has an upper limit in the low to sub micro g/g concentration range. Petroleum was one of a variety of sources identified, including plant paraffin waxes and combustion products. Beach sediment hydrocarbons were quantitatively and qualitatively similar to those of subtidal sediments. The hydrocarbon baseline in sediments of the BIOS study area was found to be as low as might be found anywhere on earth and therefore ideally suited to the BIOS study.Key words: BIOS, arctic marine Canada, hydrocarbon baseline, sedimentsMots clés: BIOS, Arctique marin canadien, niveau de référence d'hydrocarbures, sédiment

Hydrocarbon Biogeochemical Setting of the Baffin Island Oil Spill Experimental Sites. II. Water

A baseline for petroleum residues in the waters of the Cape Hatt region of Baffin Island in arctic Canada was obtained in anticipation of controlled oil releases of the Baffin Island Oil Spill (BIOS) Project. Total aliphatic and aromatic residues reflecting multiple sources were found to be in the low to sub micro g/l concentrations range. Alkylated naphthalenes, phenanthrenes and dibenzothiophenes were present in the sub ng/l concentrations range. The hydrocarbon baseline for the waters of the BIOS study area was found to be as low as might be found anywhere on earth and therefore ideally suited to the BIOS study.Key words: BIOS, arctic marine Canada, hydrocarbon baseline, waterMots clés: BIOS, Arctique marin canadien, niveau de référence d’hydrocarbures, ea

Space Station Engineering Design Issues

Space Station Freedom topics addressed include: general design issues; issues related to utilization and operations; issues related to systems requirements and design; and management issues relevant to design

Evidence for magnetic quasiparticle phase separation in a quasi-one-dimensional quantum magnet

Magnetic systems composed of weakly coupled spin-1/2 chains are fertile ground for hosting the fractional magnetic excitations that are intrinsic to interacting fermions in one-dimension (1D). However, the exotic physics arising from the quantum many-body interactions beyond 1D are poorly understood in materials of this class. Spinons and psinons are two mutually exclusive low-energy magnetic quasiparticles; the excitation seen depends on the ground state of the spin chain. Here, we present inelastic neutron scattering and neutron diffraction evidence for their coexistence in SrCo$_{2}$V$_{2}$O$_{8}$ at milli-Kelvin temperatures in part of the N\'eel phase (2.4 T $\leq$ $\mu_\mathrm{{0}}$H $<$ 3.9 T) and possibly also the field-induced spin density wave phase up to the highest field probed ($\mu_\mathrm{{0}}$H $\geq$ 3.9 T, $\mu_\mathrm{{0}}$H$_\mathbf{\mathrm{{max}}}$ = 5.5 T). These results unveil a novel spatial phase inhomogeneity for the weakly coupled spin chains in this compound. This quantum dynamical phase separation is a new phenomenon in quasi-1D quantum magnets, highlighting the non-trivial consequences of inter-chain coupling.Comment: 8 pages, 6 figure

Hydrocarbon Biogeochemical Setting of the Baffin Island Oil Spill Experimental Sites. III. Biota

A baseline for petroleum residues in the Cape Hatt region of Baffin Island in arctic Canada was obtained in anticipation of controlled oil releases of the Baffin Island Oil Spill (BIOS) Project. Tissue hydrocarbons in a variety of arctic marine species were dominated by biogenic hydrocarbons. UV/F analysis of tissues indicated an upper limit of petroleum residues in the low to sub micro g/g concentration range. PAHs were detected in samples in the low ng/g concentration range and revealed a distribution of the combustion type. The hydrocarbon baseline in the BIOS study area was found to be as low as might be found anywhere on earth and therefore ideally suited to the BIOS study.Key words: BIOS, arctic marine Canada, hydrocarbon baseline, organismsMots cl&eacute;s: BIOS, Arctique marin canadien, niveau de r&eacute;f&eacute;rence d&rsquo;hydrocarbures, organisme