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Effect of elevated CO2 and high temperature on seed-set and grain quality of rice
Hybrid vigour may help overcome the negative effects of climate change in rice. A popular rice hybrid (IR75217H), a heat-tolerant check (N22), and a mega-variety (IR64) were tested for tolerance of seed-set and grain quality to high-temperature stress at anthesis at ambient and elevated [CO2]. Under an ambient air temperature of 29 °C (tissue temperature 28.3 °C), elevated [CO2] increased vegetative and reproductive growth, including seed yield in all three genotypes. Seed-set was reduced by high temperature in all three genotypes, with the hybrid and IR64 equally affected and twice as sensitive as the tolerant cultivar N22. No interaction occurred between temperature and [CO2] for seed-set. The hybrid had significantly more anthesed spikelets at all temperatures than IR64 and at 29 °C this resulted in a large yield advantage. At 35 °C (tissue temperature 32.9 °C) the hybrid had a higher seed yield than IR64 due to the higher spikelet number, but at 38 °C (tissue temperature 34–35 °C) there was no yield advantage. Grain gel consistency in the hybrid and IR64 was reduced by high temperatures only at elevated [CO2], while the percentage of broken grains increased from 10% at 29 °C to 35% at 38 °C in the hybrid. It is concluded that seed-set of hybrids is susceptible to short episodes of high temperature during anthesis, but that at intermediate tissue temperatures of 32.9 °C higher spikelet number (yield potential) of the hybrid can compensate to some extent. If the heat tolerance from N22 or other tolerant donors could be transferred into hybrids, yield could be maintained under the higher temperatures predicted with climate change
Theory and Simulation of the diffusion of kinks on dislocations in bcc metals
Isolated kinks on thermally fluctuating (1/2) screw, edge and
(1/2) edge dislocations in bcc iron are simulated under zero stress
conditions using molecular dynamics (MD). Kinks are seen to perform stochastic
motion in a potential landscape that depends on the dislocation character and
geometry, and their motion provides fresh insight into the coupling of
dislocations to a heat bath. The kink formation energy, migration barrier and
friction parameter are deduced from the simulations. A discrete
Frenkel-Kontorova-Langevin (FKL) model is able to reproduce the coarse grained
data from MD at a fraction of the computational cost, without assuming an a
priori temperature dependence beyond the fluctuation-dissipation theorem.
Analytic results reveal that discreteness effects play an essential r\^ole in
thermally activated dislocation glide, revealing the existence of a crucial
intermediate length scale between molecular and dislocation dynamics. The model
is used to investigate dislocation motion under the vanishingly small stress
levels found in the evolution of dislocation microstructures in irradiated
materials
A Corrosion Control Manual for Rail Rapid Transit
This manual addresses corrosion problems in the design, contruction, and maintenance of rapid transit systems. Design and maintenance solutions are provided for each problem covered. The scope encompasses all facilities of urban rapid transit systems: structures and tracks, platforms and stations, power and signals, and cars. The types of corrosion and their causes as well as rapid transit properties are described. Corrosion control committees, and NASA, DOD, and ASTM specifications and design criteria to which reference is made in the manual are listed. A bibliography of papers and excerpts of reports is provided and a glossary of frequently used terms is included
Teaching Teachers for the Future (TTF) Project: Development of the TTF TPACK survey instrument
This paper presents a summary of the key findings of the TTF TPACK Survey developed and administered for the Teaching the Teachers for the Future (TTF) Project implemented in 2011. The TTF Project, funded by an Australian Government ICT Innovation Fund grant, involved all 39 Australian Higher Education Institutions which provide initial teacher education. TTF data collections were undertaken at the end of Semester 1 (T1) and at the end of Semester 2 (T2) in 2011. A total of 12881 participants completed the first survey (T1) and 5809 participants completed the second survey (T2). Groups of like-named items from the T1 survey were subject to a battery of complementary data analysis techniques. The psychometric properties of the four scales: Confidence - teacher items; Usefulness - teacher items; Confidence - student items; Usefulness- student items, were confirmed both at T1 and T2. Among the key findings summarised, at the national level, the scale: Confidence to use ICT as a teacher showed measurable growth across the whole scale from T1 to T2, and the scale: Confidence to facilitate student use of ICT also showed measurable growth across the whole scale from T1 to T2. Additional key TTF TPACK Survey findings are summarised
A new method for constructing small-bias spaces from Hermitian codes
We propose a new method for constructing small-bias spaces through a
combination of Hermitian codes. For a class of parameters our multisets are
much faster to construct than what can be achieved by use of the traditional
algebraic geometric code construction. So, if speed is important, our
construction is competitive with all other known constructions in that region.
And if speed is not a matter of interest the small-bias spaces of the present
paper still perform better than the ones related to norm-trace codes reported
in [12]
Heterodyne detection of the 752.033-GHz H2O rotational absorption line
A tunable high resolution two stage heterodyne radiometer was developed for the purpose of investigating the intensity and lineshape of the 752.033 GHz rotational transition of water vapor. Single-sideband system noise temperatures of approximately 45,000 K were obtained using a sensitive GaAs Schottky diode as the first stage mixer. First local oscillator power was supplied by a CO2 laser pumped formic acid laser (761.61 GHz), generating an X-band IF signal with theoretical line center at 9.5744 GHz. Second local oscillator power was provided by means of a 3 GHz waveguide cavity filter with only 9 dB insertion loss. In absorption measurements of the H2O taken from a laboratory simulation of a high altitude rocket plume, the center frequency of the 752 GHz line was determined to within 1 MHz of the reported value. A rotational temperature 75 K, a linewidth 5 MHz and a Doppler shift 3 MHz were measured with the line-of-sight intersecting the simulated-plume axis at a distance downstream of 30 nozzle diameters. These absorption data were obtained against continuum background radiation sources at temperatures of 1175 and 300 K
Photometric and proper motion study of neglected open cluster NGC 2215
Optical UBVRI photometric measurements using the Faulkes Telescope North were
taken in early 2011 and combined with 2MASS JHK and WISE infrared
photometry as well as UCAC4 proper motion data in order to estimate the main
parameters of the galactic open cluster NGC 2215 of which large uncertainty
exists in the current literature. Fitting a King model we estimate a core
radius of 1.120.04 (0.240.01pc) and a limiting radius of
0.5 (0.940.11pc) for the cluster. The results of isochrone
fits indicates an age of with a distance of
pc, a metallicity of dex and a reddening of
. A proportion of the work in this study was undertaken by
Australian and Canadian upper secondary school students involved in the Space
to Grow astronomy education project, and is the first scientific publication to
have utilized our star cluster photometry curriculum materials.Comment: 10 pages, 9 Figures, 3 Table
A New Measurement of the Average FUV Extinction Curve
We have measured the extinction curve in the far-ultraviolet wavelength
region of (900 -- 1200 A) using spectra obtained with the Berkeley EUV/FUV
spectrometer during the ORFEUS-I and the ORFEUS-II missions in 1993 and 1996.
From the complete sample of early-type stars observed during these missions,
we have selected pairs of stars with the same spectral type but different
reddenings to measure the differential FUV extinction. We model the effects of
molecular hydrogen absorption and exclude affected regions of the spectrum to
determine the extinction from dust alone. We minimize errors from inaccuracies
in the cataloged spectral types of the stars by making our own determinations
of spectral types based on their IUE spectra. We find substantial scatter in
the curves of individual star pairs and present a detailed examination of the
uncertainties and their effects on each extinction curve. We find that, given
the potentially large uncertainties inherent in using the pair method at FUV
wavelengths, a careful analysis of measurement uncertainties is critical to
assessing the true dust extinction. We present a new measurement of the average
far-ultraviolet extinction curve to the Lyman limit; our new measurement is
consistent with an extrapolation of the standard extinction curve of Savage &
Mathis (1979).Comment: 13 pages text, 7 figures 4 tables. Sent as gzipped tar, with ms.tex
and 7 figure
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