Ammonia oxidation is not required for growth of Group 1.1c soil Thaumarchaeota

© FEMS 2015. FUNDING EBW is funded by Centre for Genome Enabled Biology and Medicine, University of Aberdeen.Peer reviewedPublisher PD

Improved simulation of aerosol, cloud, and density measurements by shuttle lidar

Data retrievals are simulated for a Nd:YAG lidar suitable for early flight on the space shuttle. Maximum assumed vertical and horizontal resolutions are 0.1 and 100 km, respectively, in the boundary layer, increasing to 2 and 2000 km in the mesosphere. Aerosol and cloud retrievals are simulated using 1.06 and 0.53 microns wavelengths independently. Error sources include signal measurement, conventional density information, atmospheric transmission, and lidar calibration. By day, tenuous clouds and Saharan and boundary layer aerosols are retrieved at both wavelengths. By night, these constituents are retrieved, plus upper tropospheric, stratospheric, and mesospheric aerosols and noctilucent clouds. Density, temperature, and improved aerosol and cloud retrievals are simulated by combining signals at 0.35, 1.06, and 0.53 microns. Particlate contamination limits the technique to the cloud free upper troposphere and above. Error bars automatically show effect of this contamination, as well as errors in absolute density nonmalization, reference temperature or pressure, and the sources listed above. For nonvolcanic conditions, relative density profiles have rms errors of 0.54 to 2% in the upper troposphere and stratosphere. Temperature profiles have rms errors of 1.2 to 2.5 K and can define the tropopause to 0.5 km and higher wave structures to 1 or 2 km

Preliminary Observations on New Images of the Elysium Frozen Sea Deposits from HRSC Mars Express

Abstract not available

Kinetics of the Thermal Decomposition of Dimethylmercury. II. Carbon‐13 Isotope Effect

The C13 kinetic isotope effect in the pyrolysis of gaseous dimethylmercury has been studied in the presence and absence of cyclopentane inhibitor from 290–375°C for the inhibited and 290–350°C for the uninhibited reactions. The isotopic fractionation factor (S) is defined as the ratio of rate constants for the decomposition of Hg(C12H3)2 vs C12H3HgC13H3. S shows a strong dependence upon the degree of inhibition of the methyl radical chain, which, in turn, is a function of the ratio of cyclopentane to dimethylmercury. S is also a function of the total pressure.The dependence of S upon the degree of inhibition agrees quantitatively with the predictions of the mechanism proposed in I. The pressure effect on the isotope effect is attributed to the unimolecular nature of the rate determining step (Hg☒C bond rupture) and is consistent with the over‐all kinetics.The isotope rate factor in the fully inhibited high‐pressure limit, α, is 1.034±0.002 (essentially independent of temperature over the range studied), compared to a value of 1.011±0.001 for the uninhibited (chain) decomposition.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71109/2/JCPSA6-30-3-613-1.pd

Kinetics of the Thermal Decomposition of Dimethylmercury. I. Cyclopentane Inhibition

The kinetics of the pyrolysis of gaseous dimethylmercury have been studied in the presence and absence of cyclopentane inhibitor from 290–375°C for the inhibited and 265–350°C for the uninhibited reactions. The decomposition in excess cyclopentane is first order, with methane the major product (accounting for >95% of the carbon). Rate constants are dependent upon the ratio of dimethylmercury (DMM) to cyclopentane and upon total pressure. The constant for DMM loss is: kD=1.1×1015 exp(—55 900/RT) sec—1. The rate constant (from combined data on DMM loss and CH4 formation) extrapolated to the fully inhibited, high‐pressure limit is: k1=5.0×1015 exp(—57 900/RT) sec—1.The data for the uninhibited decomposition agree with the literature; a partial mechanism is suggested which predicts the transition from chain to nonchain behavior with increasing temperature.For the inhibited reaction the following mechanism is proposed: (1) Hg(CH3)2→HgCH3+CH3, (2) HgCH3→Hg+CH3, (3) CH3+Hg(CH3)2→CH4+CH3HgCH2, (4) CH3+C5H10→CH4+C5H9, (5) CH3+Hg(CH3)2→C2H6+HgCH3, (6) 2 CH3→C2H6, (7) CH3HgCH2→HgCH3+CH2.Using the present value of E1=57.9±1.4 kcal/mole in conjunction with known thermochemical data, E2=0±3 kcal/mole. From the inhibition data, k3/k4=0.7±0.2 at 300°C, with a very small temperature coefficient. The inert gas pressure effect is evidence for the unimolecular nature of step (1).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70105/2/JCPSA6-30-3-607-1.pd

African Higher Education: Researching Absences, Equalities and Aspirations

No description supplie

Vegetable and fruit intake in Australian adolescents: Trends over time and perceptions of consumption

The consumption of vegetables and fruit during adolescence is crucial to ensuring adequate intake of the nutrients required to meet the rapid growth that characterises this developmental period. However, significant reductions in vegetable and fruit intake during adolescence have been observed making the promotion of consumption an important health promotion challenge. To monitor progress in this population segment toward meeting recommended intake levels and identifying at-risk groups, the present study assessed changes in Australian adolescents’ vegetable and fruit consumption over time and identified the demographic factors associated with meeting recommendations. As individuals who are aware of their diet deficiencies are likely to be more receptive to healthy eating interventions, the present study also assessed adolescents’ perceptions of the adequacy of their vegetable and fruit intake and identified the demographic factors associated with correctly perceiving fruit and vegetable intake to be inadequate. Two cross-sectional samples of Western Australian secondary school students aged 12–17 years were surveyed in 2009–2010 (n = 1501) and 2012–2013 (n = 1406). Only 14% of students at Wave 1 and 13% at Wave 2 met the recommended guidelines for vegetable intake while 68% and 71% met the guidelines for fruit intake. Females had significantly greater odds of failing to meet guidelines for vegetable intake than males. Only 50% of students correctly identified their vegetable and fruit intake to be inadequate. The observed very low levels of compliance with vegetable intake recommendations suggest that addressing deficiencies in vegetable consumption should be a primary focus of future nutrition interventions. Efforts should also be made to increase adolescents’ perceptions of the inadequacy of their intake to optimise the effectiveness of schemes designed to improve vegetable and fruit consumption in this population segment