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Meta-analysis reveals ammonia-oxidizing bacteria respond more strongly to nitrogen addition than ammonia-oxidizing archaea
Shifts in microbial communities driven by anthropogenic nitrogen (N) addition have broad-scale ecological consequences. However, responses of microbial groups to exogenous N supply vary considerably across studies, hindering efforts to predict community changes. We used meta-analytical techniques to explore how amoA gene abundances of ammonia-oxidizing archaea (AOA) and bacteria (AOB) respond to N addition, and found that N addition increased AOA and AOB abundances by an average of 27% and 326%, respectively. Responses of AOB varied by study type, ecosystem, fertilizer type, and soil pH, and were strongest in unmanaged wildland soils and soils fertilized with inorganic N sources. Increases in nitrification potential with N addition significantly correlated with only AOB. Our analyses suggest that elevated N supply enhances soil nitrification potential by increasing AOB populations, and that this effect may be most pronounced in unmanaged wildland soils
First and second order magnetic and structural transitions in BaFeCoAs
We present here high resolution magnetization measurements on high-quality
BaFeCoAs, 0x0.046 as-grown single crystals.
The results confirm the existence of a magnetic tricritical point in the
(,) plane at x0.022 and reveal the emergence of the
heat capacity anomaly associated with the onset of the structural transition at
x0.0064. We show that the samples with doping near x
do not show superconductivity, but rather superconductivity emerges at a
slightly higher cobalt doping, x0.0315Comment: 4 pages, 5 figure
RXTE Observations of LMC X-1 and LMC X-3
Of all known persistent stellar-mass black hole candidates, only LMC X-1 and
LMC X-3 consistently show spectra that are dominated by a soft, thermal
component. We present results from long (170ksec) Rossi X-ray Timing Explorer
(RXTE) observations of LMC X-1 and LMC X-3 made in 1996 December. The spectra
can be described by a multicolor disk blackbody plus an additional high-energy
power-law. Even though the spectra are very soft (Gamma is about 2.5), RXTE
detected a significant signal from LMC X-3 up to energies of 50keV, the hardest
energy at which the object was ever detected.
Focusing on LMC X-3, we present results from the first year of an ongoing
monitoring campaign with RXTE which started in 1997 January. We show that the
appearance of the object changes considerably over its ~200d long cycle. This
variability can either be explained by periodic changes in the mass transfer
rate or by a precessing accretion disk analogous to Her X-1.Comment: 4 pages, 5 figures, also available at
http://aitzu3.ait.physik.uni-tuebingen.de/publications/preprints1998.html to
be published in "Highlights of X-Ray Astronomy, a symposium in honour of
Joachim Truemper" (B. Aschenbach et al., eds.), MPE Repor
Failure mechanisms of graphene under tension
Recent experiments established pure graphene as the strongest material known
to mankind, further invigorating the question of how graphene fails. Using
density functional theory, we reveal the mechanisms of mechanical failure of
pure graphene under a generic state of tension. One failure mechanism is a
novel soft-mode phonon instability of the -mode, whereby the graphene
sheet undergoes a phase transition and is driven towards isolated benzene rings
resulting in a reduction of strength. The other is the usual elastic
instability corresponding to a maximum in the stress-strain curve. Our results
indicate that finite wave vector soft modes can be the key factor in limiting
the strength of monolayer materials
Effect of Soil Washing on Petroleum-Hydrocarbon Distribution on Sand Surfaces
A soil washing study was performed to evaluate the treatability of New River sand contaminated in the laboratory with a petroleum distillate. Unaltered and base-extracted sands were mixed with petroleum hydrocarbons, equilibrated, and washed with water or a surfactant at two different pH values (7 and 12). The surfactant had no significant effect on contaminant removal efficiencies at neutral pH. Treatment efficiencies of baseextracted sand particles were 10 to 13% higher than for the unaltered sands. Scanning electron microscopy (SEM) with elemental X-ray microprobe was used to determine the distribution of iron and carbon on the New River sand surface. Qualitative interpretations of the SEM/X-ray photomicrographs disclosed that iron oxides were associated with organic carbon on the sand surfaces, with sulfur believed to be a constituent of the petroleum contamination. Low petroleum removal efficiencies for New River sand observed in previous studies were believed to be influenced by the high iron oxide content of the sand and the affinity of these metal oxides to bind natural and petroleum-derived organic carbon
Path integral Monte Carlo simulations of silicates
We investigate the thermal expansion of crystalline SiO in the --
cristobalite and the -quartz structure with path integral Monte Carlo
(PIMC) techniques. This simulation method allows to treat low-temperature
quantum effects properly. At temperatures below the Debye temperature, thermal
properties obtained with PIMC agree better with experimental results than those
obtained with classical Monte Carlo methods.Comment: 27 pages, 10 figures, Phys. Rev. B (in press
Cloned defective interfering influenza virus protects ferrets from pandemic 2009 influenza A virus and allows protective immunity to be established
Influenza A viruses are a major cause of morbidity and mortality in the human population, causing epidemics in the winter, and occasional worldwide pandemics. In addition there are periodic outbreaks in domestic poultry, horses, pigs, dogs, and cats. Infections of domestic birds can be fatal for the birds and their human contacts. Control in man operates through vaccines and antivirals, but both have their limitations. In the search for an alternative treatment we have focussed on defective interfering (DI) influenza A virus. Such a DI virus is superficially indistinguishable from a normal virus but has a large deletion in one of the eight RNAs that make up the viral genome. Antiviral activity resides in the deleted RNA. We have cloned one such highly active DI RNA derived from segment 1 (244 DI virus) and shown earlier that intranasal administration protects mice from lethal disease caused by a number of different influenza A viruses. A more cogent model of human influenza is the ferret. Here we found that intranasal treatment with a single dose of 2 or 0.2 µg 244 RNA delivered as A/PR/8/34 virus particles protected ferrets from disease caused by pandemic virus A/California/04/09 (A/Cal; H1N1). Specifically, 244 DI virus significantly reduced fever, weight loss, respiratory symptoms, and infectious load. 244 DI RNA, the active principle, was amplified in nasal washes following infection with A/Cal, consistent with its amelioration of clinical disease. Animals that were treated with 244 DI RNA cleared infectious and DI viruses without delay. Despite the attenuation of infection and disease by DI virus, ferrets formed high levels of A/Cal-specific serum haemagglutination-inhibiting antibodies and were solidly immune to rechallenge with A/Cal. Together with earlier data from mouse studies, we conclude that 244 DI virus is a highly effective antiviral with activity potentially against all influenza A subtypes
Frenkel line and solubility maximum in supercritical fluids
This research utilised Queen Mary’s MidPlus computational
facilities, supported by QMUL Research-IT and funded
by EPSRC Grant EP/K000128/1. K.T. is grateful to EPSRC,
C.Y. to CSC. V.V.B. is grateful to RSF (14-2200093) for
financial support
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