Abstract Introduction Urea is the most commonly used nitrogen (N) fertiliser on Australian dairy pastures, but has low N use efficiency due to high loss potential. Urease and nitrification inhibitors ...can be used to reduce these losses, however, their efficacy is highly variable and the reported impacts on productivity are inconsistent, with assessments often made using a single inhibitor across all seasons. Research question We examined the effectiveness of two commonly used inhibitors, the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBTPT) and the nitrification inhibitor 3,4-Dimethylpyrazole phosphate (DMPP) applied in a strategic program, on pasture responses to urea (U) fertiliser, and fertiliser N use efficiency in a temperate dairy pasture in Southern Australia. Materials and Methods Pasture productivity, N uptake, agronomic N use efficiency (NU A E), 15 N fertiliser recovery and soil mineral N were monitored. The nitrogen was applied in the urea form at rates of 160, 320, 480 and 640 kg N ha −1 yr −1 Results and Conclusions The majority of the plant N (64%-85%), assessed over autumn and spring growth periods using 15 N, was derived from mineralised soil organic matter (SOM). Neither of the inhibitors significantly altered pasture production or NU A E, most likely because of the major role of SOM in supplying N to plants, and because much of the applied 15 N (up to 55%) was retained in the soil (0-40 cm depth) due to microbial immobilisation. Uptake of fertiliser N was highest, up to 29% of applied N, immediately following fertiliser application and then was substantially reduced over subsequent months, reflecting low levels of mineralisation of the previously immobilised N. The total loss of applied 15 N was greater following autumn applications of N than spring applications, being 14% - 42% and 2% - 7% respectively and was attributed to volatilisation occurring primarily in autumn, with minimal leaching and denitrification predicted under the experimental conditions.
The workplace contributes significantly to the total dose of daily noise to which a person is subjected. Therefore, millions of people around the world are exposed to potentially dangerous noise ...levels and consequently, there is an urgent, global need for legislation to adequately protect the auditory health of workers. Occupational noise legislation has been adopted in many of the countries with different degrees of comprehensiveness and varying levels of sophistication. This paper presents a global view of current legislation on occupational noise in the 22 countries that make up the Americas, that is, Latin America, Canada, and the United States. Upon analysis of the legislation, there are notable differences among countries in the defined values for permissible exposure limit (PEL) and exchange rate. Of the countries that have regulations, the majority (81%) use a PEL of 85 dBA. A PEL of 85 dBA and the 3-dB exchange rate are currently used by 32% of the nations in the Americas. Most nations limit impulsive noise exposure to a peak unweighted sound pressure level of 140 dB (or dBC), while a few use slightly lower limits. However, 27% of the countries in the region still have not established regulations with respect to permissible noise levels and exchange rates. This fact is leaving millions of workers in the Americas unprotected against occupational noise. Provide an overview and analysis of the current legislation on occupational noise in the 22 countries that make up the Americas. The information on legislation, regulations, and standards discussed in this paper were obtained directly from official government sources in each country, the International Labour Organization database, or through various colleagues in each country. (1) There are notable differences among countries in the defined values for PEL and exchange rate. (2) Of the countries that have regulations, the majority (81%) use a PEL of 85 dBA. A PEL of 85 dBA and the 3-dB exchange rate are currently used by 32% of the nations in the Americas. (3) Most nations limit impulsive noise exposure to a peak unweighted sound pressure level of 140 dB (or dBC), while a few use slightly lower limits. (4) 27% of the countries in the region still have not established regulations with respect to permissible noise levels and exchange rates. (5) Millions of workers in the Americas are unprotected against occupational noise.
Fertiliser nitrogen use in Australia has increased from 35 Gg N in 1961 to 972 Gg N in 2002, and most of the nitrogen is used for growing cereals. However, the nitrogen is not used efficiently, and ...wheat plants, for example, assimilated only 41% of the nitrogen applied. This review confirms that the efficiency of fertiliser nitrogen can be improved through management practices which increase the crop's ability to compete with loss processes. However, the results of the review suggest that management practices alone will not prevent all losses (e.g. by denitrification), and it may be necessary to use enhanced efficiency fertilisers, such as controlled release products, and urease and nitrification inhibitors, to obtain a marked improvement in efficiency. Some of these products (e.g. nitrification inhibitors) when used in Australian agriculture have increased yield or reduced nitrogen loss in irrigated wheat, maize and cotton, and flooded rice, but most of the information concerning the use of enhanced efficiency fertilisers to reduce nitrogen loss to the environment has come from other countries. The potential role of enhanced efficiency fertilisers to increase yield in the various agricultural industries and prevent contamination of the environment in Australia is discussed.
Abstract
Noise levels are truly continuous in relatively few occupations, with some degree of intermittency the most common condition. The sound levels of intermittent noise are often referred to as ...non-Gaussian in that they are not normally distributed in the time domain. In some conditions, intermittent noise affects the ear differently from continuous noise, and it is this assumption that underlies the selection of the 5-dB exchange rate (ER). The scientific and professional communities have debated this assumption over recent decades. This monograph explores the effect of non-Gaussian noise on the auditory system. It begins by summarizing an earlier report by the same author concentrating on the subject of the ER. The conclusions of the earlier report supported the more conservative 3-dB ER with possible adjustments to the permissible exposure limit for certain working conditions. The current document has expanded on the earlier report in light of the relevant research accomplished in the intervening decades. Although some of the animal research has supported the mitigating effect of intermittency, a closer look at many of these studies reveals certain weaknesses, along with the fact that these noise exposures were not usually representative of the conditions under which people actually work. The more recent animal research on complex noise shows that intermittencies do not protect the cochlea and that many of the previous assumptions about the ameliorative effect of intermittencies are no longer valid, lending further support to the 3-dB ER. The neurologic effects of noise on hearing have gained increasing attention in recent years because of improvements in microscopy and immunostaining techniques. Animal experiments showing damage to auditory synapses from noise exposures previously considered harmless may signify the need for a more conservative approach to the assessment of noise-induced hearing loss and consequently the practice of hearing conservation programs.
We cloned an operon, copAB, from Enterococcus hirae encoding two P-type ATPases of 727 and 745 amino acids, respectively.
Both enzymes display heavy metal ion binding motifs in their polar N-terminal ...region. With an antibody against CopB, we showed
on Western blots that expression of the operon is induced by either low or high ambient copper concentrations. Disruption
of the copA gene renders the cells dependent, whereas copper disruption of copB results in a copper-sensitive phenotype. CopA
exhibits 35% sequence similarity to CopB and 43% similarity to the ATPase encoded by the recently cloned human Mc1 gene, a
gene responsible for the Menkes inborn error of copper metabolism. Our results imply that CopA and CopB are heavy metal ion
ATPases that regulate the cytoplasmic copper activity, with CopA serving in the uptake and CopB in the extrusion of copper.
We investigated the photodissociation mechanism of N,N-dimethylnitrosamine (CH3)2NNO (DMN) by ab intio quantum chemical methods. Inspired by an earlier study we calculated two-dimensional potential ...energy surfaces of the S1 state of DMN in its planar and pyramidal conformations. While the planar molecular geometry appears to possess no direct dissociation channel, the pyramidal configuration is dissociative yielding the products NO + (CH3)2N. Using wave packet dynamics on the planar S1 potential energy surface the experimental absorption spectrum was well reproduced which gives indirect but strong support for the nondissociative nature of this surface. The transition from the planar to the pyramidal conformation of DMN was then investigated by an ab initio molecular dynamics method which revealed the time evolution of the geometrical parameters of the molecule up to the dissociation of the N−N bond. This occurs about 90 fs after photon excitation. The calculated minimum energy path along the N−N coordinate and the structural changes of the molecule along this coordinate provided a detailed picture of this indirect dissociation or, more specific, predissociation process via conformational change.
Total energy calculations were performed for nitrous oxide and its anion N2O- by Multi Configuration Self-Consistent Field−Configuration Interaction (MCSCF−CI) methods. The shape of the lowest ...unoccupied molecular orbital (LUMO) and the energy gap between the highest occupied molecular orbital (HOMO) are evaluated for different N2−O distances and bending angles. The vertical electron affinities for the ground state and the first excited bending mode were found to be −2.1 eV, separated by about 50 meV. On the 2 A ‘ potential energy surface (PES) of negatively charged N2O the dynamics for the reaction after charge transfer on the ground state and thermally excited N2O has been studied by wave packet calculations. The molecules dissociate within 30 fs and strong rotational excitation of the N2 fragment is found. To explain the strong vibrational state selectivity we propose diabatic transitions between the 2 A ‘ and the 2 A ‘ ‘ PES to interrupt the dissociation of N2O- selectively. Implications for the dynamics of the Eley-Rideal reaction of N2O on alkali metal surfaces are discussed in connection with exoemission experiments.
Providing the information required to understand, advocate for, and supply post-acute vision rehabilitative care following brain injury, Vision Rehabilitation: Multidisciplinary Care of the Patient ...Following Brain Injury bridges the gap between theory and practice. It presents clinical information and scientific literature supporting the diagnostic
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