3,524 research outputs found
Testing and validating the CERES-wheat (Crop Estimation through Resource and Environment Synthesis-wheat) model in diverse environments
CERES-Wheat is a computer simulation model of the growth, development, and yield of spring and winter wheat. It was designed to be used in any location throughout the world where wheat can be grown. The model is written in Fortran 77, operates on a daily time stop, and runs on a range of computer systems from microcomputers to mainframes. Two versions of the model were developed: one, CERES-Wheat, assumes nitrogen to be nonlimiting; in the other, CERES-Wheat-N, the effects of nitrogen deficiency are simulated. The report provides the comparisons of simulations and measurements of about 350 wheat data sets collected from throughout the world
M-1 injector development - Philosophy and implementation
Subscale and full scale test firings of M-1 injector to improve combustion efficienc
An Economic analysis of the potential for precision farming in UK cereal production
The results from alternative spatial nitrogen application studies are analysed in economic terms and compared to the costs of precision farming hardware, software and other services for cereal crops in the UK. At current prices, the benefits of variable rate application of nitrogen exceed the returns from a uniform application by an average of £22 ha−1 The cost of the precision farming systems range from £5 to £18 ha−1 depending upon the system chosen for an area of 250 ha. The benefits outweigh the associated costs for cereal farms in excess of 80 ha for the lowest price system to 200–300 ha for the more sophisticated systems. The scale of benefits obtained depends upon the magnitude of the response to the treatment and the proportion of the field that will respond. To be cost effective, a farmed area of 250 ha of cereals, where 30% of the area will respond to variable treatment, requires an increase in crop yield in the responsive areas of between 0·25 and 1.00 t ha−1 (at £65 t−1) for the basic and most expensive precision farming systems, respectively
Evaluation of Some Properties of Soils Affected by Diesel Oil Pollution in Uyo, Niger Delta Area, Nigeria
Soil pollution due to oil spill is a common problem in the Niger Delta region of Nigeria. This necessitated the experiment to determine the effect of diesel oil pollution on some soil properties in Uyo within the Niger Delta region of Nigeria. The experiment was conducted at the University of Uyo Teaching and Research Farm in 2009. It was laid out in a completely randomized design (CRD) in triplicates. The size of the experimental plot was 60.7m2, sub-divided into three sub-plots each measuring 20.24m2. Each sub-plot was divided into five experimental units receiving the following treatments: 0 (control), 8, 11.5, 14.5 and 22.0 litres of diesel oil, which was converted into 0.0%, 1.39%, 2.50%, 3.45% and 5.06%. The results at two weeks after oil application (2WAOA) showed significant decrease in soil pH from 4.90 in the control to 4.35 in 5.06% pollution levels resulting in soil reaction being rated as extremely acid in oil polluted soils compared to the control with soil/reaction being rated as very strongly acid. There was depletion in total nitrogen and basic cations such as Ca2+, Mg2+, Na+ and K+. at 2WAOA. Carbon/nitrogen ratio increased in all the treatments, with the highest pollution level (5.06%) having 114.33±1.41. Percent base saturation increased inconsistently across the treatments with the highest being 56.96±0.003% (for 2.50% pollution) and the lowest being 44.24±0.008% (for 5.06% pollution level). The results at 18WAOA showed varying degrees of increase in the soil pH. The control plot had the pH of 6.39±0.002 and the highest pollution level of 5.06% had the pH of 6.05±0.2. The soil reaction at 18 WAOA was rated slightly acid compared to extremely acid in 2WAOA. There were varying degrees of increase in organic carbon in all the treatments. Total nitrogen also increased at 18WAOA, the increase ranged from 50-80%. Carbon/Nitrogen ratio was significantly reduced (? < 0.05) across the treatments. Basic cations and percent base saturation increased across the treatments at 18WAOA. Correlation between concentrations of diesel oil in the soil and some soil properties at 2WAOA and 18 WAOA showed that at 2 WAOA soil pH, total N and percent base saturation showed negative correlation, while organic carbon and carbon/nitrogen ratio showed positive correlation. At 18 WAOA, organic carbon and total N, showed positive correlation, while soil pH, carbon/nitrogen ratio and percent base saturation showed negative correlation. Keywords: Evaluation, Soil Properties, Oil polluted, Niger Delta Area, Nigeri
The Potentiating Response to Accentuated Eccentric Loading in Professional Football Players
The purpose of this study was to assess the acute effect of Accentuated Eccentric Loading (AEL) on countermovement jump (CMJ) height, peak power output (PPO) and peak velocity in male professional footballers using loads of 20% or 40% of body mass (AEL20 or AEL40, respectively). Twenty-three male professional football players (age 24 ± 4.5 years, range 18–34 years; body mass 80.21 ± 8.4 kg; height 178.26 ± 7.62 cm) took part in a randomised, cross-over design to test the potentiating responses of two AEL conditions (AEL20 and AEL40) versus a body weight control group (CON). Mean loads for the two conditions were 15.84 ± 1.70 kg (AEL20) and 31.67 ± 3.40 kg (AEL40). There was no significant difference between the three conditions for jump height (p = 0.507, η2G = 0.022). There were significant differences in peak power between the groups (p = 0.001, η2G = 0.154). Post hoc analysis with Bonferroni adjustment showed significantly higher peak power for both AEL conditions compared to the control group, but no significant differences between AEL conditions (CON vs. AEL20, p = 0.029, 95% CI −1016.735, −41.815, Cohen’s d = −0.56; CON vs. AEL40, p = 0.001, 95% CI −1244.995, −270.075, Cohen’s d = −0.81; AEL20 vs. AEL40, p = 0.75, 95% CI −715.720, 259.201, Cohen’s d = −0.24). There was no significant difference between the three conditions for peak velocity (p = 0.269, η2G = 0.046). AEL using either 20% or 40% of body mass may be used to increase peak power in the countermovement jump in well-trained professional football players
Inducible and combinatorial gene manipulation in mouse brain
We have deployed recombinant adeno-associated viruses equipped with
tetracycline-controlled genetic switches to manipulate gene expression in
mouse brain. Here, we show a combinatorial genetic approach for inducible,
cell type-specific gene expression and Cre/loxP mediated gene recombination in
different brain regions. Our chemical-genetic approach will help to
investigate ‘when’, ‘where’, and ‘how’ gene(s) control neuronal circuit
dynamics, and organize, for example, sensory signal processing, learning and
memory, and behavior
Adsorption of Pb2+ on magnetic modified hemp biochar prepared using microwave-assisted pyrolysis
Magnetic modified hemp biochar with an aim of high adsorption capacity and rapid adsorption rate was prepared by two simple steps using microwave pyrolyzed biochar. This was investigated as a potential green adsorbent for lead remediation from wastewater in a batch-mode experiment. The 150 – 300 µm biochar particles obtained from microwave-assisted pyrolysis of 1.5 kg hemp biomass batch at an average temperature of 600˚C were first impregnated with H2O2 and then magnetized by mixing aqueous biochar suspensions with aqueous Fe3+/Fe2+ solutions. The composition, morphology and surface chemistries of this magnetic biochar was examined by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM) and BET surface area (SBET). The SBET of the magnetic hemp biochar is 83.76 m2 g-1.
Batch sorption studies were performed for a 50 mg L-1 lead solution at room temperature and pH 5.5 using 0.02 g of the magnetic adsorbent in 20 ml solution for 2 hours. The experimental results have shown that the adsorption capacity of this magnetic adsorbent for Pb2+ is 43.97 mg g-1, about 87.94% removal within the 2 hours. Both pseudo-second-order and pseudo-first-order kinetic model could predict the adsorption and desorption kinetic process on the modified sorbent. EDX analysis are used to show the mechanisms for the adsorption of Pb2+ onto the adsorbent via mainly ion exchange. The Freundlich, Temkin and Langmuir models are used to predict the sorption isotherm in the system. The as-prepared magnetic hemp sorbent demonstrated a potential in heavy metal wastewater treatment
CAIRNS: The Cluster And Infall Region Nearby Survey III. Environmental Dependence of H-alpha Properties of Galaxies
We investigate the environmental dependence of star formation in cluster
virial regions and infall regions as part of CAIRNS (Cluster And Infall Region
Nearby Survey), a large spectroscopic survey of the infall regions surrounding
nine nearby rich clusters of galaxies. Our long-slit spectroscopy yields
estimates of star formation rates in environments from cluster cores to the
general large-scale structure. The fraction of galaxies with current star
formation in their inner disks as traced by H-alpha emission increases with
distance from the cluster and converges to the ``field'' value only at 2-3
virial radii, in agreement with other investigations. However, among galaxies
with significant current star formation (EW[Ha]geq2\AA), there is no difference
in the distribution of EW[Ha] inside and outside the virial radius. This
surprising result, first seen by Carter et al., suggests that (1) star
formation is truncated on either very short timescales or only at moderate and
high redshifts or (2) that projection effects contaminate the measurement. The
number density profiles of star-forming and non-star-forming galaxies indicate
that, among galaxies projected inside the virial radius, at least half of the
former and 20% of the latter are ``infall interlopers,'' galaxies in the infall
region but outside the virial region. The kinematics of star-forming galaxies
in the infall region closely match those of absorption-dominated galaxies. This
result shows that the star forming galaxies in the infall regions are not
interlopers from the field and excludes one model of the backsplash scenario of
galaxy transformation. Finally, we quantify systematic uncertainties in
estimating the global star formation in galaxies from their inner disks.Comment: 25 pages, 21 figures, accepted for publication in A
Microscopic Features of Adhesive Bonds for Non-Destructive Measurements
Inelastic electron tunneling spectroscopy, or lETS, provides an extremely sensitive method for monitoring the chemical and physical state of a molecular substance adsorbed onto an oxide surface. Inelastic tunneling data directly reflect the molecular vibrational frequencies of the first monolayer of adsorbed molecules and changes in the vibrational spectrum can be correlated with changes in the chemical state of the molecule/oxide interface. We have carried out lETS experiments on the components of the commercial adhesive, Hercules 3501. This epoxy system consists ·of two molecular components; diamino diphenyl sulfone (DPS) and tetraglycidycl 4,4\u27 diamino diphenyl methane (DPM). lETS spectra of the individual components and of the epoxy mixture adsorbed on aluminum oxide have been obtained and the vibrational modes and frequencies assigned by comparison with computer calculations and existing infrared optical spectra. Some evidence for an aging effect has been observed for the adsorbed DPS. This effect appears as a dramatic change in the low frequency vibrational modes and may be associated with the formation of hydrogen bonds or the polymerization of the DPS. Further studies of this effect are in progress. The effects of water permeation may be studied using D2O as a tracer. The vibrational modes of D20 are easily distinguished from those of water which may be present as a contaminant. If the exchange reaciton D2O + HCR → DHO + DCR occurs, it would be easily detected in the lETS spectrum. Initial experiments performed by simply immersing the tunnel junction into liquid D2O for several hours were unsuccessful because severe corrosion of the tunnel junction resulted. Experiments employing aluminum/aluminum oxide/adhesive/gold thin film junction for the study of H2O permeation are in progress. Further studies are planned to monitor the effects of heat treatment on the adhesive components and mixture
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