115 resultados para ASSISTED REPRODUCTIVE TECHNOLOGY
Resumo:
Molecular breeding is becoming more practical as better technology emerges. The use of molecular markers in plant breeding for indirect selection of important traits can favorably impact breeding efficiency. The purpose of this research is to identify quantitative trait loci (QTL) on molecular linkage groups (MLG) which are associated with seed protein concentration, seed oil concentration, seed size, plant height, lodging, and maturity, in a population from a cross between the soybean cultivars 'Essex' and 'Williams.' DNA was extracted from F-2 generation soybean leaves and amplified via polymerase chain reaction (PCR) using simple sequence repeat (SSR) markers. Markers that were polymorphic between the parents were analyzed against phenotypic trait data from the F-2 and F-4:6 generation. For the F-2 population, significant additive QTL were Satt540 (MLG M, maturity, r(2)=0.11; height, r(2)=0.04, seed size, r(2)=0.061, Satt373 (MLG L, seed size, r(2)=0.04; height, r(2)=0.14), Satt50 (MLG A1, maturity r(2)=0.07), Satt14 (MLG D2, oil, r(2)=0.05), and Satt251 (protein r(2)=0.03, oil, r(2)=0.04). Significant dominant QTL for the F-2 population were Satt540 (MLG M, height, r(2)=0.04; seed size, r(2)=0.06) and Satt14 (MLG D2, oil, r(2)=0.05). In the F-4:6 generation significant additive QTL were Satt239 (MLG I, height, r(2)=0.02 at Knoxville, TN and r(2)=0.03 at Springfield, TN), Satt14 (MLG D2, seed size, r(2)=0.14 at Knoxville, TN), Satt373 (MLG L, protein, r(2)=0.04 at Knoxville, TN) and Satt251 (MLG B I, lodging r(2)=0.04 at Springfield, TN). Averaged over both environments in the F-4:6 generation, significant additive QTL were identified as Satt251 (MLG B 1, protein, r(2)=0.03), and Satt239 (MLG 1, height, r(2)=0.03). The results found in this study indicate that selections based solely on these QTL would produce limited gains (based on low r(2) values). Few QTL were detected to be stable across environments. Further research to identify stable QTL over environments is needed to make marker-assisted approaches more widely adopted by soybean breeders.
Resumo:
BP Refinery (Bulwer Island) Ltd (BP) located on the eastern Australian coast is currently undergoing a major expansion as a part of the Queensland Clean Fuels Project. The associated wastewater treatment plant upgrade will provide a better quality of treated effluent than is currently possible with the existing infrastructure, and which will be of a sufficiently high standard to meet not only the requirements of imposed environmental legislation but also BP's environmental objectives. A number of challenges were faced when considering the upgrade, particularly; cost constraints and limited plot space, highly variable wastewater, toxicity issues, and limited available hydraulic head. Sequencing Batch Reactor (SBR) Technology was chosen for the lagoon upgrade based on the following; SBR technology allowed a retro-fit of the existing earthen lagoon without the need for any additional substantial concrete structures, a dual lagoon system allowed partial treatment of wastewaters during construction, SBRs give substantial process flexibility, SBRs have the ability to easily modify process parameters without any physical modifications, and significant cost benefits. This paper presents the background to this application, an outline of laboratory studies carried out on the wastewater and details the full scale design issues and methods for providing a cost effective, efficient treatment system using the existing lagoon system.
Resumo:
The work of Michel Foucault sees modern penal technology its ann expression of power that operates through and is motivated by a dry instrumental reason. This article draws upon Durkheim and Bakhtin to advance a radically alternative approach. It is suggested that such technology is invested with sacred and profane symbolism and is understood via emotionally charged, dramatically compelling narrative frames. Tensions between official and unauthorized discourses can be understood through a center/periphery model of culture. In an extended case study of the guillotine, it is shown dial the apparatus was initially legitimated as an expression of a sacred revolutionary code. Such a discourse was subsequently destabilized by popular medical debates that raised the specter of pain after decapitation. While inconclusive, these new motifs mobilized Gothic and grotesque themes that confronted the rationalist aesthetics of the guillotine. A situation of Bakhtinian hetoroglossia eventuated. Uncertainty, the uncanny and fable entered a discursive field of increasing complexity.
Resumo:
Ethephon promotes fruit abscission and accelerates harvest of macadamia, Macadamia integrifolia (Proteaceae), but has limited use due to concerns that associated abscission of inner-canopy leaves may reduce subsequent yield and nut quality. Yield and quality were monitored for 2 years following ethephon application to both unshaken and mechanically shaken trees of the late-abscising cultivar, A16. Nut quality was not adversely affected in subsequent seasons, but effects on yield varied. In 3 of 6 experiments, ethephon reduced yield in the year after application. However, in 4 of the 6 experiments, 2 years of ethephon application greatly elevated yield in the third year. This was not a compensating recovery from low second-year yield, as third-year yield of trees that received only 1 ethephon treatment did not differ from yield of control trees. Ethephon-assisted harvest remains feasible for macadamia, although further work is warranted given the potential risks and considerable benefits for subsequent yield. Inner canopy defoliation, resulting from ethephon use, could represent a canopy management technique for dense-canopy fruit trees.
Resumo:
Throughout the latter months of 2000 and early 2001, the Australian public, media and parliament were engaged in a long and emotive debate about motherhood. This debate constructed the two main protagonists, the unborn 'child' and the potential mother, with a variety of different and often oppositional identities. The article looks at the way that these subject identities interacted during the debate, starting from the premise that policy making has unintended and unacknowledged material outcomes, and using governmentality as a tool through which to analyse and understand processes of identity manipulation and resistance within policy making. The recent debate concerning the right of lesbian and single women to access new reproductive technologies in Australia is used as a case study. Nominally the debate was about access to IVF technology; in reality, however, the debate was about the governing of women and, in particular, the governing of motherhood identities. The article focuses on the parliamentary debate over the drafting of legislation designed to stop lesbian and single women from accessing these technologies, particularly the utilization of the 'unborn' subject within these debates as a device to discipline the identity of 'mother'.
Resumo:
A switch-mode assisted linear amplifier (SMALA) combining a linear (Class B) and a switch-mode (Class D) amplifier is presented. The usual single hysteretic controlled half-bridge current dumping stage is replaced by two parallel buck converter stages, in a parallel voltage controlled topology. These operate independently: one buck converter sources current to assist the upper Class B output device, and a complementary converter sinks current to assist the lower device. This topology lends itself to a novel control approach of a dead-band at low power levels where neither class D amplifier assists, allowing the class B amplifier to supply the load without interference, ensuring high fidelity. A 20 W implementation demonstrates 85% efficiency, with distortion below 0.08% measured across the full audio bandwidth at 15 W. The class D amplifier begins assisting at 2 W, and below this value, the distortion was below 0.03%. Complete circuitry is given, showing the simplicity of the additional class D amplifier and its corresponding control circuitry.
Resumo:
Low temperature during panicle development in rice increases spikelet sterility. This effect is exacerbated by high rates of nitrogen (N) application in the field. Spikelet sterility induced by low temperature and N fertilisation was examined in glasshouse experiments to clarify the mechanisms involved. In two glasshouse experiments, 12-h periods of low (18/13degreesC) and high (28/23degreesC) day/night temperatures were imposed over periods of 5-7 days during panicle development, to determine the effects of low temperature and N fertilisation on spikelet sterility. In one experiment, 50% sunlight was imposed together with low temperature to investigate the additive effects of reduced solar radiation and low temperature. The effect of increased tillering due to N fertilisation was examined by a tiller removal treatment in the same experiment. Pollen grain number and spikelet sterility were recorded at heading and harvest, respectively. Although there was no significant effect of low temperature on spikelet sterility in the absence of applied N, low temperature greatly increased spikelet sterility as a result of a reduction in the number of engorged pollen grains per anther in the presence of applied N. Spikelet sterility was strongly correlated with the number of engorged pollen grains per anther. Low temperature during very early ( late stage of spikelet differentiation-pollen mother cell stage) and peak ( second meiotic division stage-early stage of extine formation) microspore development caused a severe reduction in engorged pollen production mainly as a result of reduced total pollen production. Unlike low temperature, the effect of shading was rather small. The increased tillering due to application of high rates of N, increased both spikelet number per plant and spikelet sterility under low temperature conditions. The removal of tillers as they appeared reduced the number of total spikelets per plant and maintained a large number of engorged pollen grains per anther which, in turn, reduced spikelet sterility. The number of engorged pollen grains per anther determined the numbers of intercepted and germinated pollen grains on the stigma. It is concluded that N increased tillering and spikelet number per plant and this, in turn, reduced the number of engorged pollen grains per anther, leading into increased spikelet sterility under low temperature condition.