2,224 research outputs found
A meta-analysis on the effects of climate change on the yield and quality of European pastures
A Systems Approach to Assessing the Viability of Grazing Legume Systems Across Europe
Forage legumes are important in grassland farming throughout much of the world because of their ability to fix atmospheric nitrogen, and hence they are expected to play an increasingly prominent role in low- input grazing farming systems in Europe. Nevertheless, the socio-economic impact of the adoption of the new legume based grazing technologies have been poorly researched (Rochon et al., 2004). Thus a methodology has been developed to:
* Assess the on-farm costs and benefits of including different legume crops for animal production;* Determine the types of management systems and environmental conditions under which forage legumes may play a major part as grazing crops in production systems in Europe;* and Determine the wider social, economic and environmental implication of widespread adoption of the new technologies
Elastic response of [111]-tunneling impurities
We study the dynamic response of a [111] quantum impurity, such as lithium or
cyanide in alkali halides, with respect to an external field coupling to the
elastic quadrupole moment. Because of the particular level structure of a
eight-state system on a cubic site, the elastic response function shows a
biexponential relaxation feature and a van Vleck type contribution with a
resonance frequency that is twice the tunnel frequency . This
basically differs from the dielectric response that does not show relaxation.
Moreover, we show that the elastic response of a [111] impurity cannot be
reduced to that of a two-level system. In the experimental part, we report on
recent sound velocity and internal friction measurements on KCl doped with
cyanide at various concentrations. At low doping (45 ppm) we find the dynamics
of a single [111] impurity, whereas at higher concentrations (4700 ppm) the
elastic response rather indicates strongly correlated defects. Our theoretical
model provides a good description of the temperature dependence of
and at low doping, in particular the relaxation peaks, the absolute
values of the amplitude, and the resonant contributions. From our fits we
obtain the value of the elastic deformation potential eV.Comment: 19 pages, 5 figure
Soft Interaction Between Dissolved Dendrimers: Theory and Experiment
Using small-angle neutron scattering and liquid integral equation theory, we
relate the structure factor of flexible dendrimers of 4th generation to their
average shape. The shape is measured as a radial density profile of monomers
belonging to a single dendrimer. From that, we derive an effective interaction
of Gaussian form between pairs of dendrimers and compute the structure factor
using the hypernetted chain approximation. Excellent agreement with the
corresponding experimental results is obtained, without the use of adjustable
parameters. The present analysis thus strongly supports the previous finding
that flexible dendrimers of low generation present fluctuating structures akin
to star polymers.Comment: 20 pages, 4 figures, submitted to Macromolecules on July 24, 200
Developing a nationally appropriate mitigation measure from the greenhouse gas abatement potential from livestock production in the Brazilian Cerrado.
Brazil is one of the first major developing countries to commit to a national greenhouse gas (GHG) emissions target that requires a reduction of between 36.1% and 38.9% relative to baseline emissions by 2020. The country intends to submit to agricultural emissions reductions as part of this target with livestock production identified as offering significant abatement potentia
Low temperature acoustic properties of amorphous silica and the Tunneling Model
Internal friction and speed of sound of a-SiO(2) was measured above 6 mK
using a torsional oscillator at 90 kHz, controlling for thermal decoupling,
non-linear effects, and clamping losses. Strain amplitudes e(A) = 10^{-8} mark
the transition between the linear and non-linear regime. In the linear regime,
excellent agreement with the Tunneling Model was observed for both the internal
friction and speed of sound, with a cut-off energy of E(min) = 6.6 mK. In the
non-linear regime, two different behaviors were observed. Above 10 mK the
behavior was typical for non-linear harmonic oscillators, while below 10 mK a
different behavior was found. Its origin is not understood.Comment: 1 tex file, 6 figure
Future proofing a long-term agricultural experiment for decades to come : Relocation and redesign
We are extremely grateful to generations of staff at SRUC and its predecessor organisations (NOSCA and SAC) for maintaining the Woodlands Field experiments at Craibstone over 100 years and to I&N Campbell who carefully prepared the new site and moved the soils in July 2021. The move of the soils was funded by SRUC. The molecular analysis of the soils from the pH experiment was conducted within the Soil Biology and Soil Health (SBSH) Partnership, funded by the Agriculture and Horticulture Development Board (AHDB) and the British Beet Research Organisation (BBRO) in the United Kingdom. We also gratefully acknowledge many colleagues from research and consultancy organisations in the UK and Europe who contributed to discussions during the redesign process. Professor Tony Edwards and Dr John Baddeley were both integral to the decision to move and redesign the pH Experiment. We are grateful to Allan Lilly, James Hutton Institute for allowing us to archive soils from both Woodlands Field experiments in the National Soils Archive. Thank you to Rosie Boyko and Nicola Holden (SRUC) and John Elphinstone (FERA) for useful discussions on the new experimental designs and the manuscript.Peer reviewe
Biological efficiency profiles over the lactation period in multiparous high-producing dairy cows under divergent production systems
The study examined variation in energetic-efficiency profiles among
production systems and cow parities. Further, the correlation between cows'
body condition score (BCS) and energetic efficiency over the lactation period was
determined. Biological efficiency was defined using four measures of
production efficiency and two measures of energetic efficiency. The following were measures of
energetic efficiency: the net energy intake required to produce 1 kg milk
solids (NEin / MS) and the proportion of net energy utilized for milk
production after accounting for maintenance
(NElact / (NEin- NEm)). Seven years of data were gathered from a
total of 595 Holstein-Friesian cows in a long-term genetics × feeding–management interaction project. Two feeding regimes – High forage
(HF) and Low forage (LF) – were applied to each of two genetic lines (Control
(C) and Select (S)), giving four dairy production systems: Low Forage Control
(LFC), Low Forage Select (LFS), High Forage Control (HFC) and High Forage
Select (HFS). LFS was the most efficient system using all measures.
Variation in the rate and scale of change at which the cows' energetic
efficiency declined over lactation was significantly different
(P < 0.001) amongst different dairy production systems and
parities. Loss of efficiency over the lactation period was lower in Select cows
than in Control cows and increased with parity. The trajectory of energetic-efficiency profiles was influenced by cow genetic line, and yet the level of
the efficiency profile was influenced by the feeding regime. There was a strong
relationship between BCS and energetic efficiency. Continued in situ monitoring of
cows' biological efficiency may enable optimal management of dairy systems
Physical Properties of the Soils of Agricultural Watersheds 1 and 13 which Control Moisture, Storage, and Transport: Final Report on Project 12, Agricultural Watershed Studies, Task C, Canadian Section, Activity 1
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