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Resumo:
A simple, reliable, and efficient method has been elaborated for direct determination of isotopic composition of authigenic uranium in siliceous lacustrine sediments. The method is based on studying kinetics of selective extraction of authigenic uranium from sediments by weak solutions of ammonium hydrocarbonate followed by ICP-MS analysis of nuclides. To estimate contamination of authigenic uranium by terrigenous one contents of 232Th and some other clastogenic elements in the extracts were measured simultaneously. Selectivity of extraction of authigenic uranium from the sediments treated with 1% NH4HCO3 solution appeared to be no worse than 99%. The method was applied to analysis of isotopic composition of authigenic uranium at several key horizons of the earlier dated core from the Baikal Lake. Measurements directly show that 234U/238U values in Baikal water varied depending on climate, which contradicts existing hypotheses. Measured 234U/238U ratios in water of the paleo-Baikal match corresponding values reconstructed from isotopic data for total uranium in the sediments on supposition that U/Th ratio is constant in terrigenous fraction of the sediments. Direct experimental determination of total and authigenic nuclides in sediments enhances potentiality of the method for 234U-230Th dating of non-carbonate lacustrine sediments including those from the Baikal Lake within intervals corresponding to periods of glaciation, when sediments were rich in terrigenous components. Portions of terrigenous and authigenic uranium are well separated and we can study variability of sources of terrigenous matter and refine the earlier model for reconstructing climate humidity in the East Siberia.
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All but the last three works are by William Penn.
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In both Australia and Brazil there are rapid changes occurring in the macroenvironment of the dairy industry. These changes are sometimes not noticed in the microenvironment of the farm, due to the labour-intensive nature of family farms, and the traditionally weak links between production and marketing. Trends in the external environment need to be discussed in a cooperative framework, to plan integrated actions for the dairy community as a whole and to demand actions from research, development and extension (R, D & E). This paper reviews the evolution of R, D & E in terms of paradigms and approaches, the present strategies used to identify dairy industry needs in Australia and Brazil, and presents a participatory strategy to design R, D & E actions for both countries. The strategy incorporates an integration of the opinions of key industry actors ( defined as members of the dairy and associated communities), especially farm suppliers ( input market), farmers, R, D & E people, milk processors and credit providers. The strategy also uses case studies with farm stays, purposive sampling, snowball interviewing techniques, semi-structured interviews, content analysis, focus group meetings, and feedback analysis, to refine the priorities for R, D & E actions in the region.
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An artificial diet incorporating insect cells originally developed for Trichogramma australicum Girault (Hymenoptera: Tricho-grammatidae) was successfully used to rear Trichogramm pretiosum Riley (Hymenoptera: Trichogrammatidae). To refine the diet, individual components were removed. Chicken egg yolk and the insect cells were identified as the most important components for T. pretiosum development. Their removal resulted in few pupae and no adults. Removal of Grace's insect medium, a common component of artificial diets, was found to markedly improve the development of T pretiosum, producing 60% larva to pupa transition and 19% pupa to adult transition. There was no significant difference in T pretiosum development on diets in which milk powder, malt powder or infant formula were interchanged, despite differences in nutrient composition. The use of yeast extract resulted in significantly higher survival to the adult stage when compared with yeast hydrolysate enzymatic and a combination of yeast extract and yeast hydrolysate enzymatic. Comparison of four antimicrobial agents showed the antibacterial agent Gentamycin and the antifungal agent Nystatin had the least detrimental effect on T pretiosum development. The use of insect cell line diets has the potential to simplify artificial diet production and significantly reduce T pretiosum production costs in Australia compared to diets using insect hemolymph or the use of natural or factitious hosts. (c) 2005 Elsevier Inc. All rights reserved.
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Elevated ocean temperatures can cause coral bleaching, the loss of colour from reef-building corals because of a breakdown of the symbiosis with the dinoflagellate Symbiodinium. Recent studies have warned that global climate change could increase the frequency of coral bleaching and threaten the long-term viability of coral reefs. These assertions are based on projecting the coarse output from atmosphere-ocean general circulation models (GCMs) to the local conditions around representative coral reefs. Here, we conduct the first comprehensive global assessment of coral bleaching under climate change by adapting the NOAA Coral Reef Watch bleaching prediction method to the output of a low- and high-climate sensitivity GCM. First, we develop and test algorithms for predicting mass coral bleaching with GCM-resolution sea surface temperatures for thousands of coral reefs, using a global coral reef map and 1985-2002 bleaching prediction data. We then use the algorithms to determine the frequency of coral bleaching and required thermal adaptation by corals and their endosymbionts under two different emissions scenarios. The results indicate that bleaching could become an annual or biannual event for the vast majority of the world's coral reefs in the next 30-50 years without an increase in thermal tolerance of 0.2-1.0 degrees C per decade. The geographic variability in required thermal adaptation found in each model and emissions scenario suggests that coral reefs in some regions, like Micronesia and western Polynesia, may be particularly vulnerable to climate change. Advances in modelling and monitoring will refine the forecast for individual reefs, but this assessment concludes that the global prognosis is unlikely to change without an accelerated effort to stabilize atmospheric greenhouse gas concentrations.
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Objective: To report on strategies for, and outcomes of, evaluation of knowledge (publications), health and wealth (commercial) gains from medical research funded by the Australian Government through the National Health and Medical Research Council (NHMRC). Design and methods: End-of-grant reports submitted by researchers within 6 months of completion of NHMRC funded project grants which terminated in 2003 were used to capture self-reported publication number, health and wealth gains. Self-reported gains were also examined in retrospective surveys of grants completed in 1992 and 1997 and awards primarily supporting people (“people awards”) held between 1992 and 2002. Results: The response rate for the 1992 sample was too low for meaningful analysis. The mean number of publications per grant in the basic biomedical, clinical and health services research areas was very similar in 1997 and 2003. The publication output for population health was somewhat higher in the 2003 than in the 1997 analysis. For grants completed in 1997, 24% (31/131) affected clinical practice; 14% (18/131) public health practice; 9% (12/131) health policy; and 41% (54/131) had commercial potential with 20% (26/131) resulting in patents. Most respondents (89%) agreed that NHMRC people awards improved their career prospects. Interpretation is limited by the relatively low response rates (50% or less). Conclusions: A mechanism has been developed for ongoing assessment of NHMRC funded research. This process will improve accountability to the community and to government, and refine current funding mechanisms to most efficiently deliver health and economic returns for Australia.
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Research councils, agencies, and researchers recognize the benefits of team-based health research. However, researchers involved in large-scale team-based research projects face multiple challenges as they seek to identify epistemological and ontological common ground. Typically, these challenges occur between quantitative and qualitative researchers but can occur between qualitative researchers, particularly when the project involves multiple disciplinary perspectives. The authors use the convergent interviewing technique in their multidisciplinary research project to overcome these challenges. This technique assists them in developing common epistemological and ontological ground while enabling swift and detailed data collection and analysis. Although convergent interviewing is a relatively new method described primarily in marketing research, it compares and contrasts well with grounded theory and other techniques. The authors argue that this process provides a rigorous method to structure and refine research projects and requires researchers to identify and be accountable for developing a common epistemological and ontological position.
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Bacterial chaperonin, GroEL, together with its co-chaperonin, GroES, facilitates the folding of a variety of polypeptides. Experiments suggest that GroEL stimulates protein folding by multiple cycles of binding and release. Misfolded proteins first bind to an exposed hydrophobic surface on GroEL. GroES then encapsulates the substrate and triggers its release into the central cavity of the GroEL/ES complex for folding. In this work, we investigate the possibility to facilitate protein folding in molecular dynamics simulations by mimicking the effects of GroEL/ES namely, repeated binding and release, together with spatial confinement. During the binding stage, the (metastable) partially folded proteins are allowed to attach spontaneously to a hydrophobic surface within the simulation box. This destabilizes the structures, which are then transferred into a spatially confined cavity for folding. The approach has been tested by attempting to refine protein structural models generated using the ROSETTA procedure for ab initio structure prediction. Dramatic improvements in regard to the deviation of protein models from the corresponding experimental structures were observed. The results suggest that the primary effects of the GroEL/ES system can be mimicked in a simple coarse-grained manner and be used to facilitate protein folding in molecular dynamics simulations. Furthermore, the results Sur port the assumption that the spatial confinement in GroEL/ES assists the folding of encapsulated proteins.
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Learning from mistakes has proven to be an effective way of learning in the interactive document classifications. In this paper we propose an approach to effectively learning from mistakes in the email filtering process. Our system has employed both SVM and Winnow machine learning algorithms to learn from misclassified email documents and refine the email filtering process accordingly. Our experiments have shown that the training of an email filter becomes much effective and faster
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Primary aldosteronism (PAL) is caused by the autonomous over-production of aldosterone. Once thought rare, it is now reported to be responsible for 5–10% of hypertension. Familial hyperaldosteronism type II (FH-II), unlike familial hyperaldosteronism type I, is not glucocorticoid-remediable and not associated with the hybrid CYP11B1/CYP11B2 gene mutation. At least five times more common than FH-I, FH-II is clinically, biochemically and morphologically indistinguishable from apparently sporadic PAL, suggesting that its incidence maybe even higher. Studies performed in collaboration with C Stratakis (NIH, Bethesda) on our largest Australian FH-II family (eight affected members) demonstrated linkage at chromosome 7p22. Similar linkage at this region was also found in a South American FH-II family (DNA provided by MI New, Presbyterian Hospital, New York). Mutations in the exons and intron/exon boundaries of the PRKARIB gene (which resides at 7p22 and is closely related to PRKARIA gene mutated in Carney complex) have been excluded in our largest Australian FH-II family. Using more finely spaced markers, we have confirmed linkage at 7p22 in these 2 families, and identified a second Australian family with evidence of linkage at this locus. The combined multipoint LOD score for these 3 families is 4.87 (θ=0) with markers D7S462 and D7S2424, which exceeds the critical threshold for genome-wide significance suggested by Lander and Kruglyak (1995), providing strong support for this locus harbouring mutations responsible for FH-II. A newly identified recombination event in our largest Australian family has narrowed the region of linkage by 1.8 Mb, permitting exclusion of approximately half the genes residing in the original reported 5Mb linked locus. In addition, we have strongly excluded linkage to these key markers in two Australian families (maximum multipoint LOD scores −3.51 and −2.77), supporting the notion that FH-II may be genetically heterogeneous. In order to identify candidate genes at 7p22, more closely spaced markers will be used to refine the locus, as well as single nucleotide polymorphism analysis.
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A major task of traditional temporal event sequence mining is to predict the occurrences of a special type of event (called target event) in a long temporal sequence. Our previous work has defined a new type of pattern, called event-oriented pattern, which can potentially predict the target event within a certain period of time. However, in the event-oriented pattern discovery, because the size of interval for prediction is pre-defined, the mining results could be inaccurate and carry misleading information. In this paper, we introduce a new concept, called temporal feature, to rectify this shortcoming. Generally, for any event-oriented pattern discovered under the pre-given size of interval, the temporal feature is the minimal size of interval that makes the pattern interesting. Thus, by further investigating the temporal features of discovered event-oriented patterns, we can refine the knowledge for the target event prediction.
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Research in verification and validation (V&V) for concurrent programs can be guided by practitioner information. A survey was therefore run to gain state-of-practice information in this context. The survey presented in this paper collected state-of-practice information on V&V technology in concurrency from 35 respondents. The results of the survey can help refine existing V&V technology by providing a better understanding of the context of V&V technology usage. Responses to questions regarding the motivation for selecting V&V technologies can help refine a systematic approach to V&V technology selection.
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Three-dimensional computer modelling techniques are being used to develop a probabilistic model of turbulence-related spray transport around various plant architectures to investigate the influence of plant architectures and crop geometry on the sprayapplication process. Plant architecture models that utilise a set of growth rules expressed in the Lindenmayer systems (L-systems) formalism have been developed and programmed using L-studio software. Modules have been added to simulate the movement ofdroplets through the air and deposition on the plant canopy. Deposition of spray on an artificial plant structure was measured in the wind tunnel at the University of Queensland, Gatton campus and the results compared to the model simulation. Further trials are planned to measure the deposition of spray droplets on various crop and weed species and the results from these trials will be used to refine and validate the combined spray and plant architecture model.
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Literature on the relationship between leadership and entrepreneurship as it applies to endogenous growth in a regional context is reviewed and used to explore a research agenda for work on this topic. A leadership/entrepreneurship analytical approach is developed and applied on a pilot basis to the Greater Washington D.C. region and its sub-parts. The results are assessed and used to further refine the model and to identify some of the more provocative policy implications of this work. The implications for regional planning process are also considered.
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Esta pesquisa, Responsabilidade Social, Pregação e Educação: tensões missiológicas no projeto missionário da Igreja Metodista em terras brasileiras, tem como objetivo analisar as ações missionárias da Igreja Metodista do período de sua implantação até o final do período referente ao 18° Concílio Geral (2006-2011). A análise resgatou a tríade Responsabilidade Social, Pregação e Educação como uma marca identitária do movimento wesleyano e que esse princípio missionário nem sempre foi seguido pelo metodismo brasileiro. Notou-se também que a tríade serviu, em momentos decisivos, como elemento norteador do projeto missionário. Isso é percebido no período da implantação, bem como na constituição do Plano para Vida e Missão (PVM). Em que pese que as ações missionárias no metodismo brasileiro nem sempre foram providas de uma reflexão teológica sistemática, a tríade Responsabilidade Social, Pregação e Educação sempre funcionou como eixos essenciais da missão e de forma indissociável. Não foram poucos os momentos em que o projeto missionário metodista enfrentou tensões na sua execução. O ímpeto pelo crescimento numérico e expansão geográfica, muitas vezes, ofuscou a fidelidade à tríade. Nessa trajetória de pesquisa está construída em quatro capítulos, nos quais se busca a superação de uma compreensão histórica equivocada e faz-se necessário que o projeto missionário assuma os elementos essenciais da tríade como marco regulatório da missão metodista. As repetitivas opções equivocadas não colaboram com a nova compreensão de missão. O resultado da pesquisa encoraja futuras análises para que o metodismo assuma o papel de agente de Deus na missio Dei e para que o seu envolvimento missionário mantenha fidelidade à tríade Responsabilidade Social, Pregação e Educação.