962 resultados para plant and machinery
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Bibliography: p. 1-153.
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"To subscribers" (note concerning errata in v. 1): l leaf, inserted at end of v. 2.
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Two-way N transfers mediated by Pisolithus sp. were examined by excluding root contact and supplying (NH4+)-N-15 or (NO3-)-N-15 to 6-month-old Eucalyptus maculata or Casuarina cunninghamiana grown in two-chambered-pots separated by 37 m screens. Mycorrhizal colonization was 35% in Eucalyptus and 66% in Casuarina (c. 29% N-2-fixation). Using an environmental scanning electron microscope, living hyphae were observed to interconnect Eucalyptus and Casuarina. Biomass and N accumulation was greatest in nodulated mycorrhizal Casuarina/mycorrhizal Eucalyptus pairs, less in nonnodulated mycorrhizal Casuarina/mycorrhizal Eucalyptus pairs, and least in nonnodulated nonmycorrhizal Casuarina/nonmycorrhizal Eucalyptus pairs. In nonnodulated mycorrhizal pairs, N transfers to Eucalyptus or to Casuarina were similar (2.4-4.1 mg per plant in either direction) and were 2.6-4.0 times greater than in nonnodulated nonmycorrhizal pairs. In nodulated mycorrhizal pairs, N transfers were greater to Eucalyptus (5-7 times) and to Casuarina (12-18 times) than in nonnodulated mycorrhizal pairs. Net transfer to Eucalyptus or to Casuarina was low in both nonnodulated nonmycorrhizal (< 0.7 mg per plant) and nonnodulated mycorrhizal pairs (< 1.1 mg per plant). In nodulated mycorrhizal pairs, net transfer to Casuarina was 26.0 mg per plant. The amount and direction of two-way mycorrhiza-mediated N transfer was increased by the presence of Pisolithus sp. and Frankia, resulting in a net N transfer from low-N-demanding Eucalyptus to high-N-demanding Casuarina.
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In Australian freshwaters, Anabaena circinalis, Microcystis spp. and Cylindrospermopsis raciborskii are the dominant toxic cyanobacteria. Many of these Surface waters are used as drinking water resources. Therefore, the National Health and Medical Research Council of Australia set a guideline for MC-LR toxicity equivalents of 1.3 mug/l drinking, water. However, due to lack of adequate data, no guideline values for paralytic shellfish poisons (PSPs) (e.g. saxitoxins) or cylindrospermopsin (CYN) have been set. In this spot check. the concentration of microcystins (MCs), PSPs and CYN were determined by ADDA-ELISA, cPPA, HPLC-DAD and/or HPLC-MS/MS, respectively, in two water treatment plants in Queensland/Australia and compared to phytoplankton data collected by Queensland Health, Brisbane. Depending on the predominant cyanobacterial species in a bloom, concentrations of up to 8.0, 17.0 and 1.3 mug/l were found for MCs, PSPs and CYN, respectively. However, only traces (< 1.0 mug/l) of these toxins were detected in final water (final product of the drinking water treatment plant) and tap water (household sample). Despite the low concentrations of toxins detected in drinking water, a further reduction of cyanobacterial toxins is recommended to guarantee public safety. (C) 2004 Elsevier Ltd. All rights reserved.
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We studied the relationships among plant and arbuscular mycorrhizal (AM) fungal diversity, and their effects on ecosystem function, in a series of replicate tropical forestry plots in the La Selva Biological Station, Costa Rica. Forestry plots were 12 yr old and were either monocultures of three tree species, or polycultures of the tree species with two additional understory species. Relationships among the AM fungal spore community, host species, plant community diversity and ecosystem phosphorus-use efficiency (PUE) and net primary productivity (NPP) were assessed. Analysis of the relative abundance of AM fungal spores found that host tree species had a significant effect on the AM fungal community, as did host plant community diversity (monocultures vs polycultures). The Shannon diversity index of the AM fungal spore community differed significantly among the three host tree species, but was not significantly different between monoculture and polyculture plots. Over all the plots, significant positive relationships were found between AM fungal diversity and ecosystem NPP, and between AM fungal community evenness and PUE. Relative abundance of two of the dominant AM fungal species also showed significant correlations with NPP and PUE. We conclude that the AM fungal community composition in tropical forests is sensitive to host species, and provide evidence supporting the hypothesis that the diversity of AM fungi in tropical forests and ecosystem NPP covaries.
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A key function of activated macrophages is to secrete proinflammatory cytokines such as TNF alpha; however, the intracellular pathway and machinery responsible for cytokine trafficking and secretion is largely undefined. Here we show that individual SNARE proteins involved in vesicle docking and fusion are regulated at both gene and protein expression upon stimulation with the bacterial cell wall component lipopolysaccharide. Focusing on two intracellular SNARE proteins, Vti1b and syntaxin 6 (Stx6), we show that they are up-regulated in conjunction with increasing cytokine secretion in activated macrophages and that their levels are selectively titrated to accommodate the volume and timing of post-Golgi cytokine trafficking. In macrophages, Vti1b and syntaxin 6 are localized on intracellular membranes and are present on isolated Golgi membranes and on Golgi-derived TNF alpha vesicles budded in vitro. By immunoprecipitation, we find that Vti1b and syntaxin 6 interact to form a novel intracellular Q-SNARE complex. Functional studies using overexpression of full-length and truncated proteins show that both Vti1b and syntaxin 6 function and have rate-limiting roles in TNF alpha trafficking and secretion. This study shows how macrophages have uniquely adapted a novel Golgi-associated SNARE complex to accommodate their requirement for increased cytokine secretion.
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Latexin, the only known mammalian carboxypeptidase inhibitor, has no detectable sequence similarity with plant and parasite inhibitors, but it is related to a human putative tumor suppressor protein, TIG1. Latexin is expressed in the developing brain, and we find that it plays a role in inflammation, as it is expressed at high levels and is inducible in macrophages in concert with other protease inhibitors and potential protease targets. The crystal structure of mouse latexin, solved at 1.83 Angstrom resolution, shows no structural relationship with other carboxypeptidase inhibitors. Furthermore, despite a lack of detectable sequence duplication, the structure incorporates two topologically analogous domains related by pseudo two-fold symmetry. Surprisingly, these domains share a cystatin fold architecture found in proteins that inhibit cysteine proteases, suggesting an evolutionary and possibly functional relationship. The structure of the tumor suppressor protein TIG1 was modeled, revealing its putative membrane binding surface.
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We have mapped and identifed DNA markers linked to morphology, yield, and yield components of lucerne, using a backcross population derived from winter-active parents. The high-yielding and recurrent parent, D, produced individual markers that accounted for up to 18% of total yield over 6 harvests, at Gatton, south-eastern Queensland. The same marker, AC/TT8, was consistently identified at each individual harvest, and in individual harvests accounted for up to 26% of the phenotypic variation for yield. This marker was located in linkage group 2 of the D map, and several other markers positively associated with yield were consistently identified in this linkage group. Similarly, markers negatively associated with yield were consistently identified in the W116 map, W116 being the low-yielding parent. Highly significant positive correlations were observed between total yield and yield for harvests 1-6, and between total yield and stem length, tiller number, leaf yield/plant, leaf yield/5 stems, stem yield/plant, and stem yield/5 stems. Highly significant QTL were located for all these characters as well as for leaf shape and pubescence.
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The work presented was conducted within the scope of a larger study investigating impacts of the Stuart Oil Shale project, a facility operating to the north of the industrial city of Gladstone, Australia. The aims of the investigations were threefold: (a) the identification of the plant signatures in terms of particle size distributions in the submicrometer range (13-830 nm) through stack measurements, (b) exploring the applicability of these signatures in tracing the source contributions at locations of interest, at a distance from the plant, and (c) assessing the contribution of the plant to the total particle number concentration at locations of interest. The stack measurements conducted for three different conditions of plant operation showed that the particle size distributions were bimodal with average modal count median diameters (CMDs) of 24 (SD 4) and 52 (SD 9) nm. The average of all the particle size distributions recorded within the plant sector at a site located 4.5 km from the plant, over the sampling period when the plant was operating, also showed a bimodal distribution. The modal CMDs in this case were 27 and 50 nm, similar to those at the stack. This bimodal size distribution is distinct from the size distribution of the most common ambient anthropogenic emission source, which is vehicle emissions, and can be considered as a signature of this source. The average contribution of the plant (for plant sector winds) was estimated to be (10.0 +/- 3.8) x 10(2) particles cm(-3) and constituted approximately a 50% increase over the local particle ambient concentration for plant sector winds. This increase in particle number concentration compared to the local background concentration, while high compared to the clean environment concentration, is not significant when compared to concentrations generally encountered in the urban environment of Brisbane.
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This paper presents a composite multi-layer classifier system for predicting the subcellular localization of proteins based on their amino acid sequence. The work is an extension of our previous predictor PProwler v1.1 which is itself built upon the series of predictors SignalP and TargetP. In this study we outline experiments conducted to improve the classifier design. The major improvement came from using Support Vector machines as a "smart gate" sorting the outputs of several different targeting peptide detection networks. Our final model (PProwler v1.2) gives MCC values of 0.873 for non-plant and 0.849 for plant proteins. The model improves upon the accuracy of our previous subcellular localization predictor (PProwler v1.1) by 2% for plant data (which represents 7.5% improvement upon TargetP).
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This article examines variations in local input linkages in foreign transnational corporations in Malaysia. The extent to which transnational corporations foster such linkages, particularly in a developing host economy, has become an important issue for policy makers and others concerned with the long-term benefits associated with foreign direct investment. This article employs a unique data set, covering inward investors in the electrical and electronics industry, and analyzes in detail the determinants of variations in local input uses. The article develops a model of local input linkages, based on a transaction-cost framework using firm-specific factors, such as nationality of ownership, the age of the plant and its technology, and the extent to which firms employ locally recruited managers and engineers. In addition, the impacts of various policy measures on local input levels are discussed, and also the importance of the original motivation for investing in Malaysia. The article demonstrates that policy initiatives that target particular outcomes, such as stimulating exports or technology transfer, will result in a greater beneficial impact on the host country economy than more generic subsidies.
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A prominent theme emerging in Occupational Health and Safety (OSH) is the development of management systems. A range of interventions, according to a prescribed route detailed by one of the management systems, can be introduced into an organisation with some expectation of improved OSH performance. This thesis attempts to identify the key influencing factors that may impact upon the process of introducing interventions, (according to B88800: 1996, Guide to Implementing Occupational Health and Safety Management Systems) into an organisation. To help identify these influencing factors a review of possible models from the sphere of Total Quality Management (TQM) was undertaken and the most suitable TQM model selected for development and use in aSH. By anchoring the aSH model's development in the reviewed literature a range ofeare, medium and low level influencing factors were identified. This model was developed in conjunction with the research data generated within the case study organisation (rubber manufacturer) and applied to the organisation. The key finding was that the implementation of an OSH intervention was dependant upon three broad vectors of influence. These are the Incentive to introduce change within an organisation which refers to the drivers or motivators for OSH. Secondly the Ability within the management team to actually implement the changes refers to aspects, amongst others, such as leadership, commitment and perceptions of OSH. Ability is in turn itself influenced by the environment within which change is being introduced. TItis aspect of Receptivity refers to the history of the plant and characteristics of the workforce. Aspects within Receptivity include workforce profile and organisational policies amongst others. It was found that the TQM model selected and developed for an OSH management system intervention did explain the core influencing factors and their impact upon OSH performance. It was found that within the organisation the results that may have been expected from implementation of BS8800:1996 were not realised. The OSH model highlighted that given the organisation's starting point, a poor appreciation of the human factors of OSH, gave little reward for implementation of an OSH management system. In addition it was found that general organisational culture can effectively suffocate any attempts to generate a proactive safety culture.
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This thesis describes the development of a simple and accurate method for estimating the quantity and composition of household waste arisings. The method is based on the fundamental tenet that waste arisings can be predicted from information on the demographic and socio-economic characteristics of households, thus reducing the need for the direct measurement of waste arisings to that necessary for the calibration of a prediction model. The aim of the research is twofold: firstly to investigate the generation of waste arisings at the household level, and secondly to devise a method for supplying information on waste arisings to meet the needs of waste collection and disposal authorities, policy makers at both national and European level and the manufacturers of plant and equipment for waste sorting and treatment. The research was carried out in three phases: theoretical, empirical and analytical. In the theoretical phase specific testable hypotheses were formulated concerning the process of waste generation at the household level. The empirical phase of the research involved an initial questionnaire survey of 1277 households to obtain data on their socio-economic characteristics, and the subsequent sorting of waste arisings from each of the households surveyed. The analytical phase was divided between (a) the testing of the research hypotheses by matching each household's waste against its demographic/socioeconomic characteristics (b) the development of statistical models capable of predicting the waste arisings from an individual household and (c) the development of a practical method for obtaining area-based estimates of waste arisings using readily available data from the national census. The latter method was found to represent a substantial improvement over conventional methods of waste estimation in terms of both accuracy and spatial flexibility. The research therefore represents a substantial contribution both to scientific knowledge of the process of household waste generation, and to the practical management of waste arisings.
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In 1974 Dr D M Bramwell published his research work at the University of Aston a part of which was the establishment of an elemental work study data base covering drainage construction. The Transport and Road Research Laboratory decided to, extend that work as part of their continuing research programme into the design and construction of buried pipelines by placing a research contract with Bryant Construction. This research may be considered under two broad categories. In the first, site studies were undertaken to validate and extend the data base. The studies showed good agreement with the existing data with the exception of the excavation trench shoring and pipelaying data which was amended to incorporate new construction plant and methods. An inter-active on-line computer system for drainage estimating was developed. This system stores the elemental data, synthesizes the standard time of each drainage operation and is used to determine the required resources and construction method of the total drainage activity. The remainder of the research was into the general topic of construction efficiency. An on-line command driven computer system was produced. This system uses a stochastic simulation technique, based on distributions of site efficiency measurements to evaluate the effects of varying performance levels. The analysis of this performance data quantities the variability inherent in construction and demonstrates how some of this variability can be reconciled by considering the characteristics of a contract. A long term trend of decreasing efficiency with contract duration was also identified. The results obtained from the simulation suite were compared to site records collected from current contracts. This showed that this approach will give comparable answers, but these are greatly affected by the site performance parameters.
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Plant oxylipins are a large family of metabolites derived from polyunsaturated fatty acids. The characterization of mutants or transgenic plants affected in the biosynthesis or perception of oxylipins has recently emphasized the role of the so-called oxylipin pathway in plant defense against pests and pathogens. In this context, presumed functions of oxylipins include direct antimicrobial effect, stimulation of plant defense gene expression, and regulation of plant cell death. However, the precise contribution of individual oxylipins to plant defense remains essentially unknown. To get a better insight into the biological activities of oxylipins, in vitro growth inhibition assays were used to investigate the direct antimicrobial activities of 43 natural oxylipins against a set of 13 plant pathogenic microorganisms including bacteria, oomycetes, and fungi. This study showed unequivocally that most oxylipins are able to impair growth of some plant microbial pathogens, with only two out of 43 oxylipins being completely inactive against all the tested organisms, and 26 oxylipins showing inhibitory activity toward at least three different microbes. Six oxylipins strongly inhibited mycelial growth and spore germination of eukaryotic microbes, including compounds that had not previously been ascribed an antimicrobial activity such as 13-keto-9(Z),11(Z),15(Z)- octadecatrienoic acid and 12-oxo-10,15(Z)-phytodienoic acid. Interestingly this first large-scale comparative assessment of the antimicrobial effects of oxylipins reveals that regulators of plant defense responses are also the most active oxylipins against eukaryotic microorganisms, suggesting that such oxylipins might contribute to plant defense through their effects both on the plant and on pathogens, possibly through related mechanisms. © 2005 American Society of Plant Biologists.