967 resultados para quasi-phase-matching


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The authors examine the critical divergence of the low-frequency conductivity of the noninteracting Fermi glass and interacting electron glass models of the insulating phase of a disordered system as the metallic phase is approached. Results for the two are found to be rather different, which can be tested experimentally. In particular, for the electron glass, there exists a nonvanishing contribution to the dielectric constants from the low-frequency (hopping) conductivity even at low temperatures, which scales with the high-frequency (optical) contribution, and diverges with the same exponent at the insulator-metal transition.

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Regional variety trials (RVT) established in 1983 and again in 1997 identified superior varieties for the macadamia industry. From the 1983 trials, guidelines were developed to assist growers to select the most appropriate new varieties for their particular orchards and many of these superior varieties have been enthusiastically adopted by industry. This is also being done for varieties in the 1997 trials. Many of the best cultivars have already been adopted by growers on the basis of annual reports of yield and quality. Industry development over the next 10 to 20 years will be largely dependent on new, superior varieties selected in these RVT5, including new selections from the macadamia industry breeding program.

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We have used phase field simulations to study the effect of misfit and interfacial curvature on diffusion-controlled growth of an isolated precipitate in a supersaturated matrix. Treating our simulations as computer experiments, we compare our simulation results with those based on the Zener–Frank and Laraia–Johnson–Voorhees theories for the growth of non-misfitting and misfitting precipitates, respectively. The agreement between simulations and the Zener–Frank theory is very good in one-dimensional systems. In two-dimensional systems with interfacial curvature (with and without misfit), we find good agreement between theory and simulations, but only at large supersaturations, where we find that the Gibbs–Thomson effect is less completely realized. At small supersaturations, the convergence of instantaneous growth coefficient in simulations towards its theoretical value could not be tracked to completion, because the diffusional field reached the system boundary. Also at small supersaturations, the elevation in precipitate composition matches well with the theoretically predicted Gibbs–Thomson effect in both misfitting and non-misfitting systems.

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The previous projects (phase I - III) highlighted that northern region wheat and barley cultivars differ considerably in their sensitivity to herbicides. The new project will focus on increased screening of advanced breeding lines and new cultivars lines to commonly used herbicides, for barley, chickpea and wheat. Studies on impact of environment on herbicide x genotype responses will also be undertaken with the national team. The new information will be added to the existing information package on herbicide tolerance. Thus, adverse impacts of herbicides on productivity in northern region will be reduced, as growers and agronomists will select safer herbicides for their sown variety, or select more tolerant varieties for their important herbicides.

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A national focus on strategic and applied research to minimise herbicide resistance in Australian cropping.

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This project employed a participatory development and extension (D&E) approach involving on-farm trials and capacity- building activities to improve the economic and environmental performance of grain and mixed farming enterprises in central Queensland (CQ). The project's activities delivered (1) enhanced knowledge and understanding of key system variables that underpin grain and mixed farming businesses, and parameter values for these variables in relation to a range of environmental and management factors, (2) new and refined practices, technologies and management strategies to sustain the profitability of cropping and (3) products and information to support continuous improvement in farm business performance.

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Jointly manage The Farm Program within the Cotton Catchment Communities CRC.

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The threat and management of glyphosate# resistant weeds are major issues facing northern region growers. At present five weeds are confirmed glyphosate-resistant: barnyard grass, liverseed grass, windmill grass, annual ryegrass and flaxleaf fleabane. This project used 25 experiments to investigate the ecology of the grass weeds, plus new or improved chemical and non-chemical control tactics for them. The refined glyphosate resistance model developed in this project used the experiments' findings to predict the long-term impacts on evolution of resistance and on seed bank numbers of resistant weeds. These data led to revised management and resistance avoidance strategies, which were published in the Reporter newsletter, and via an on-line risk assessment tool. - See more at: http://finalreports.grdc.com.au/UQ00054#sthash.oTkCN4Sk.dpuf

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The results of the pilot demonstrated that a pharmacist delivered vaccinations services is feasible in community pharmacy and is safe and effective. The accessibility of the pharmacist across the influenza season provided the opportunity for more people to be vaccinated, particularly those who had never received an influenza vaccine before. Patient satisfaction was extremely high with nearly all patients happy to recommend the service and to return again next year. Factors critical to the success of the service were: 1. Appropriate facilities 2. Competent pharmacists 3. Practice and decision support tools 4. In-­‐store implementation support We demonstrated in the pilot that vaccination recipients preferred a private consultation area. As the level of privacy afforded to the patients increased (private room vs. booth), so did the numbers of patients vaccinated. We would therefore recommend that the minimum standard of a private consultation room or closed-­‐in booth, with adequate space for multiple chairs and a work / consultation table be considered for provision of any vaccination services. The booth or consultation room should be used exclusively for delivering patient services and should not contain other general office equipment, nor be used as storage for stock. The pilot also demonstrated that a pharmacist-­‐specific training program produced competent and confident vaccinators and that this program can be used to retrofit the profession with these skills. As vaccination is within the scope of pharmacist practice as defined by the Pharmacy Board of Australia, there is potential for the universities to train their undergraduates with this skill and provide a pharmacist vaccination workforce in the near future. It is therefore essential to explore appropriate changes to the legislation to facilitate pharmacists’ practice in this area. Given the level of pharmacology and medicines knowledge of pharmacists, combined with their new competency of providing vaccinations through administering injections, it is reasonable to explore additional vaccines that pharmacists could administer in the community setting. At the time of writing, QPIP has already expanded into Phase 2, to explore pharmacists vaccinating for whooping cough and measles. Looking at the international experience of pharmacist delivered vaccination, we would recommend considering expansion to other vaccinations in the future including travel vaccinations, HPV and selected vaccinations to those under the age of 18 years. Overall the results of the QPIP implementation have demonstrated that an appropriately trained pharmacist can deliver safely and effectively influenza vaccinations to adult patients in the community. The QPIP showed the value that the accessibility of pharmacists brings to public health outcomes through improved access to vaccinations and the ability to increase immunisation rates in the general population. Over time with the expansion of pharmacist vaccination services this will help to achieve more effective herd immunity for some of the many diseases which currently have suboptimal immunisation rates.

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During the past 10 years, this project tested 23 barley and 51 wheat varieties with 19 and 34 registered herbicides, respectively. It concentrated on new varieties and herbicides. The research highlighted that Northern Region (NR) wheat and barley varieties differed considerably in their sensitivity to these herbicides. Overall, 9 per cent of wheat variety x herbicide combinations and 6 per cent of barley variety x herbicide combinations had significant yield losses (3 to 38%) from herbicides at recommended rates and crop stages. In addition, 21 to 23 per cent had significant yield losses from herbicides at double rates, indicating a narrow margin of crop safety.

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Improved economic and social performance of grain and mixed farming businesses in Central Queensland.

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Dichromated gelatin is thought to be a good substitute for photographic emulsions in some uses. The results of a systematic study of the effect of the pH of the developer on the diffraction efficiency of volume holographic gratings recorded in dye sensitized dichromated gelatin are presented.

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Octahedral Co2+ centers have been connected by mu(3)-OH and mu(2)-OH2 units forming [Co-4] clusters which are linked by pyrazine forming a two-dimensional network. The two-dimensional layers are bridged by oxybisbenzoate (OBA) ligands giving rise to a three-dimensional structure. The [Co-4] clusters bond with the pyrazine and the OBA results in a body-centered arrangement of the clusters, which has been observed for the first time. Magnetic studies reveal a noncollinear frustrated spin structure of the bitriangular cluster, resulting in a net magnetic moment of 1.4 mu B per cluster. For T > 32 K, the correlation length of the cluster moments shows a stretched-exponential temperature dependence typical of a Berezinskii-Kosterlitz-Thouless model, which points to a quasi-2D XY behavior. At lower temperature and down to 14 K, the compound behaves as a soft ferromagnet and a slow relaxation is observed, with an energy barrier of ca. 500 K. Then, on further cooling, a hysteretic behavior takes place with a coercive field that reaches 5 Tat 4 K. The slow relaxation is assigned to the creation/annihilation of vortex-antivortex pairs, which are the elementary excitations of a 2D XY spin system.

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Detailed ESR investigations of Mn2+ substituting for Ca2+ in Ca2Sr(C2H5COO)6, (DSP) and Ca2Pb(C2H5COO)6, (DLP) and Ca2Ba(C2H5COO)6, (DBP), in single crystals and powders, over the temperature range from 300°C to -180°C have been carried out to study the successive phase transitions in these compounds. Spectra have been analyzed in terms of axial spin Hamiltonians and the temperature dependences of the parameters studied. Across the I-II transition, new physically and chemically inequivalent sites appear indicating the disappearance of the diad axes on which the propionate groups are located, bringing out the connection between the motional states of the propionate groups and the occurrence of ferroelectricity. The II-III transition also causes chemically inequivalent sites to develop, indicating that the transitions may not be isomorphous as believed previously. Similarities and dissimilarities of the ESR spectra of DLP, DSP and DBP are discussed in relation to the phase transitions.