1,147 research outputs found
Optimal use of animal slurries for input reduction and protection of the environment in sustainable agricultural systems.
End of Project ReportThis work was funded by the EU Air Programme (AIR-CT 94-1276) 1st October 1994 - 30th September 1997The objectives of manure management in sustainable agricultural systems
are to optimise nutrient recovery by the crop and to reduce nutrient
losses to the environment. However, farmers still have many practical
problems in adopting and applying the research developed for
improving manure management strategies. This project identified and
addressed three of these problems. These concerned the provision of
decision support in relation to environmental risk assessment and
application decision strategies; determining the nutrient value of slurry
and the development of manure application technology.European
Structural Funding (EAGGF
Effect of an agri-environmental measure on nitrate leaching from a beef farming system in Ireland
peer-reviewedAgricultural nitrogen (N) management remains a key environmental challenge. Improving N management is a matter of urgency to reduce the serious ecological consequences of the reactive N. Nitrate (NO3−–N) leaching was measured under suckler beef production systems stocked at two intensities: (1) intensive, 210 kg organic N ha−1 with two cut silage harvests; and (2) rural environmental protection scheme (REPS), 170 kg organic N ha−1 with one cut silage harvest. Three replicate plots of each treatment were instrumented with ceramic cups (8 per plot), randomly placed within each plot at a depth of 1 m to collect soil solution for NO3−–N at 50 kPa suction to collecting vessels one week prior to sampling. Samples were taken on a total of 53 sampling dates over 3 winter drainage periods (2002/03, 2003/04 and 2004/05). Over the course of the experiment the mean annual soil solution NO3−–N concentration exceeded the MAC twice out of 15 means (5 treatments over 3 years). The REPS grazing and silage sub treatments had significantly lower mean annual soil solution total oxidized N (TON) concentrations than the respective intensive treatments in years 2 and 3. Annual total NO3−–N losses over the three years in intensive and REPS systems ranged from 55 to 71 and 15 to 20 kg N ha−1, respectively. Mean N surpluses in intensive and REPS systems were 210 and 95 kg ha−1, respectively with the corresponding mean N inputs of 272 and 124 kg N ha−1. The reduction in N inputs under the REPS system results in lower N leaching losses and contributed to a significant reduction in pressures on water quality
A two-stage approach for measuring vascular water exchange and arterial transit time by diffusion-weighted perfusion MRI
Changes in the exchange rate of water across the blood-brain barrier, denoted kw, may indicate blood-brain barrier dysfunction before the leakage of large-molecule contrast agents is observable. A previously proposed approach for measuring kw is to use diffusion-weighted arterial spin labeling to measure the vascular and tissue fractions of labeled water, because the vascular-to-tissue ratio is related to kw. However, the accuracy of diffusion-weighted arterial spin labeling is affected by arterial blood contributions and the arterial transit time (τa). To address these issues, a two-stage method is proposed that uses combinations of diffusion-weighted gradient strengths and post-labeling delays to measure both τa and kw. The feasibility of this method was assessed by acquiring diffusion-weighted arterial spin labeling data from seven healthy volunteers. Repeat measurements and Monte Carlo simulations were conducted to determine the precision and accuracy of the kw estimates. Average grey and white matter kw values were 110 ± 18 and 126 ± 18 min-1, respectively, which compare favorably to blood-brain barrier permeability measurements obtained with positron emission tomography. The intrasubject coefficient of variation was 26% ± 23% in grey matter and 21% ± 17% in white matter, indicating that reproducible kw measurements can be obtained. Copyright © 2011 Wiley Periodicals, Inc
The architecture of cancellous bone in the hindlimb of moa (Aves: Dinornithiformes), with implications for stance and gait
The extinct, flightless moa of New Zealand included some of the largest birds to have existed and possessed many distinguishing pelvic and hindlimb osteological features. These features may have influenced stance and gait in moa compared with extant birds. One means of assessing locomotor biomechanics, particularly for extinct species, is quantitative analysis of the architecture of cancellous bone, since this architecture is adapted to suit its mechanical environment with high sensitivity. This study investigated the three-dimensional architecture of cancellous bone in the femur, tibiotarsus and fibula of three moa species: Dinornis robustus, Pachyornis elephantopus and Megalapteryx didinus. Using computed tomographic X-ray scanning and previously developed fabric analysis techniques, the spatial variation in cancellous bone fabric patterns in moa was found to be largely comparable with that previously reported for extant birds, particularly large species. Moa hence likely used postures and kinematics similar to those employed by large extant bird species, but this interpretation is tentative on account of relatively small sample sizes. A point of major difference between moa and extant birds concerns the diaphyses; cancellous bone invades the medullary cavity in both groups, but the invasion is far more extensive in moa. Combined with previous assessments of cortical geometry, this further paints a picture of at least some moa species possessing very robust limb bones, for which a convincing explanation remains to be determine
Magnetic-interference patterns in Josephson junctions with d+is symmetry
The magnetic interference pattern and the spontaneous flux in unconventional
Josephson junctions of superconductors with d+is symmetry are calculated for
different reduced junction lengths and the relative factor of the d and s wave
components. This is a time reversal broken symmetry state. We study the
stability of the fractional vortex and antivortex which are spontaneously
formed and examine their evolution as we change the length and the relative
factor of d and s wave components. The asymmetry in the field modulated
diffraction pattern exists for lengths as long as L=10\lambda_J.Comment: 8 pages, 6 eps files, submitted to PR
Mitotic Potential of the Enamel Organ of the Rhesus Monkey
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66907/2/10.1177_00220345650440062901.pd
Measurements of Scintillation Efficiency and Pulse-Shape for Low Energy Recoils in Liquid Xenon
Results of observations of low energy nuclear and electron recoil events in
liquid xenon scintillator detectors are given. The relative scintillation
efficiency for nuclear recoils is 0.22 +/- 0.01 in the recoil energy range 40
keV - 70 keV. Under the assumption of a single dominant decay component to the
scintillation pulse-shape the log-normal mean parameter T0 of the maximum
likelihood estimator of the decay time constant for 6 keV < Eee < 30 keV
nuclear recoil events is equal to 21.0 ns +/- 0.5 ns. It is observed that for
electron recoils T0 rises slowly with energy, having a value ~ 30 ns at Eee ~
15 keV. Electron and nuclear recoil pulse-shapes are found to be well fitted by
single exponential functions although some evidence is found for a double
exponential form for the nuclear recoil pulse-shape.Comment: 11 pages, including 5 encapsulated postscript figure
Homogeneous shear flow of a hard-sphere fluid: Analytic solutions
Recently, a solution for collision-free trajectories in an N particle thermostatted hard-sphere system undergoing homogeneous shear (the so-called "Sllod" equations of motion) led to a kinetic theory of dilute hard-sphere gases under shear. However, a solution for collisions, necessary for a complete theory at higher densities, has been missing. We present an analytic solution to this problem, which provides surprising insights into the mechanical aspects of thermostatting a system in an external field. The equivalence of constant temperature and constant energy ensembles in the thermodynamic limit in equilibrium, the conditions for the nature of heat exchange with the environment (entropy creation and reduction) in the system, and the condition for appearance of the artificial string phase follow from our solution
Fulminant hyperpyrexia induced by bleomycin
Mild and self-limiting fever following bleomycin use is common, and a fatal hyperpyrexial response occurs rarely. In previously reported cases, such hyperpyrexia occurred either after the initial administration of the drug or during subsequent therapy following an initial pyrexial response. We describe a fatal hyperpyrexial reaction after bleomycin in a patient with T-cell lymphoma who had had no febrile response when she received her initial injection 3 weeks earlier. Since the occurrence of this hyperpyrexial response is unpredictable, health care workers as well as patients and relatives should always be alert to this potentially lethal complication and prompt measures should be taken in any patient who develops fever after bleomycin use.published_or_final_versio
Comparison of s- and d-wave gap symmetry in nonequilibrium superconductivity
Recent application of ultrafast pump/probe optical techniques to
superconductors has renewed interest in nonequilibrium superconductivity and
the predictions that would be available for novel superconductors, such as the
high-Tc cuprates. We have reexamined two of the classical models which have
been used in the past to interpret nonequilibrium experiments with some
success: the mu* model of Owen and Scalapino and the T* model of Parker.
Predictions depend on pairing symmetry. For instance, the gap suppression due
to excess quasiparticle density n in the mu* model, varies as n^{3/2} in d-wave
as opposed to n for s-wave. Finally, we consider these models in the context of
S-I-N tunneling and optical excitation experiments. While we confirm that
recent pump/probe experiments in YBCO, as presently interpreted, are in
conflict with d-wave pairing, we refute the further claim that they agree with
s-wave.Comment: 14 pages, 11 figure
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