1,476 research outputs found
The effect of copper on nitrogen fixation in subterranean clover (Trifolium subterraneum)
Copper deficiency decreased nitrogen fixation in subterranean clover. Three lines of evidence support this conclusion. Firstly, while both copper and nitrogen application increased the growth of the legume the interaction between copper and nitrogen on growth was negative. Secondly, the application of copper increased the concentrations of both total and protein nitrogen in the plant. Lastly, nitrogen fixation as measured by the acetylene reduction assay increased with copper application to the soil
Improving the Utilisation of Germplasm of \u3cem\u3eTrifolium Spumosum\u3c/em\u3e L. By the Development of a Core Collection Using Ecogeographical and Molecular Techniques
A core collection is a sub-set encompassing more than 70% of the variability of all accessions held in a collection (Brown 1995), the development of one for Trifolium spumosum (bladder clover) could assist in future development of the cultivar within southern Australia. The aim of this work is to develop a core collection of Trifolium spumosum as a model for other pasture legume species using molecular and ecogeographical data
Improving the Utilisation of Germplasm of \u3cem\u3eTrifolium Spumosum\u3c/em\u3e L. By the Development of a Core Collection Using Ecogeographical and Molecular Techniques
A core collection is a sub-set encompassing more than 70% of the variability of all accessions held in a collection (Brown, 1995). The development of one for Trifolium spumosum (bladder clover) could assist in future development of the cultivar within southern Australia. The aim of this work is to develop a core collection of Trifolium spumosum as a model for other pasture legume species using molecular and ecogeographical data
What matters in economics teaching and learning? A case study of an introductory macroeconomics course in South Africa
Publisher versionIn many universities, economics lecturers now face the challenge of dealing with large, diverse classes, especially at undergraduate level. A common concern is the non-attendance at lectures of unmotivated (conscript) students. Poor lecture quality, as reflected in student evaluations of teaching (SETs), is often blamed for lack of attendance and consequent poor performance. This paper presents the results of a student assessment of a macroeconomics 1 course, coupled with a self-assessment of their own input into the course. The results obtained, using econometric models, suggest that students inputs and attitudes to the course are equally, or more, important than lecture attendance itself
Evolution of the solar irradiance during the Holocene
Aims. We present a physically consistent reconstruction of the total solar
irradiance for the Holocene. Methods. We extend the SATIRE models to estimate
the evolution of the total (and partly spectral) solar irradiance over the
Holocene. The basic assumption is that the variations of the solar irradiance
are due to the evolution of the dark and bright magnetic features on the solar
surface. The evolution of the decadally averaged magnetic flux is computed from
decadal values of cosmogenic isotope concentrations recorded in natural
archives employing a series of physics-based models connecting the processes
from the modulation of the cosmic ray flux in the heliosphere to their record
in natural archives. We then compute the total solar irradiance (TSI) as a
linear combination of the jth and jth + 1 decadal values of the open magnetic
flux. Results. Reconstructions of the TSI over the Holocene, each valid for a
di_erent paleomagnetic time series, are presented. Our analysis suggests that
major sources of uncertainty in the TSI in this model are the heritage of the
uncertainty of the TSI since 1610 reconstructed from sunspot data and the
uncertainty of the evolution of the Earth's magnetic dipole moment. The
analysis of the distribution functions of the reconstructed irradiance for the
last 3000 years indicates that the estimates based on the virtual axial dipole
moment are significantly lower at earlier times than the reconstructions based
on the virtual dipole moment. Conclusions. We present the first physics-based
reconstruction of the total solar irradiance over the Holocene, which will be
of interest for studies of climate change over the last 11500 years. The
reconstruction indicates that the decadally averaged total solar irradiance
ranges over approximately 1.5 W/m2 from grand maxima to grand minima
meson production in Au collisions at GeV
The PHENIX experiment has measured meson production in Au
collisions at GeV using the dimuon and dielectron decay
channels. The meson is measured in the forward (backward) -going
(Au-going) direction, () in the transverse-momentum
() range from 1--7 GeV/, and at midrapidity in the
range below 7 GeV/. The meson invariant yields and
nuclear-modification factors as a function of , rapidity, and centrality
are reported. An enhancement of meson production is observed in the
Au-going direction, while suppression is seen in the -going direction, and
no modification is observed at midrapidity relative to the yield in
collisions scaled by the number of binary collisions. Similar behavior was
previously observed for inclusive charged hadrons and open heavy flavor
indicating similar cold-nuclear-matter effects.Comment: 484 authors, 16 pages, 12 figures, 6 tables. v1 is the version
accepted for publication in Phys. Rev. C. Data tables for the points plotted
in the figures are given in the paper itsel
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