117 research outputs found

    Nitrogen Transformations in Broiler Litter-Amended Soils

    Get PDF
    Nitrogen mineralization rates in ten surface soils amended with (200 μg N g−1 soil) or without broiler litter were investigated. The soil-broiler litter mixture was incubated at 25±1∘C for 28 weeks. A nonlinear regression approach for N mineralization was used to estimate the readily mineralizable organic N pools (N0) and the first-order rate constant (k). The cumulative N mineralized in the nonamended soils did not exceed 80 mg N kg−1 soil. However, in Decatur soil amended with broiler litter 2, it exceeded 320 mg N kg−1 soil. The greatest calculated N0 of the native soils was observed in Sucarnoochee soil alone (123 mg NO3− kg−1 soil) which when amended with broiler litter 1 reached 596 mg N kg−1 soil. The added broiler litter mineralized initially at a fast rate (k1) followed by a slow rate (k2) of the most resistant fraction. Half-life of organic N remaining in the soils alone varied from 33 to 75 weeks and from 43 to 15 weeks in the amended soils. When N0 was regressed against soil organic N (=0.782∗∗) and C (=0.884∗∗∗), positive linear relationships were obtained. The N0 pools increased with sand but decreased with silt and clay contents

    Neuroblastomas with chromosome 11q loss and single copy MYCN comprise a biologically distinct group of tumours with adverse prognosis

    Get PDF
    Neuroblastoma is a heterogeneous tumour and its effective clinical management is dependent on accurate prognostic evaluation. In approximately 25% of patients amplification of the MYCN oncogene is known to be associated with a poor outcome. In order to identify additional molecular markers with prognostic potential in non-MYCN-amplified neuroblastomas, we looked for a correlation between clinical outcome and loss of heterozygosity (LOH) on four chromosomes that frequently show alteration in neuroblastoma (chromosomes 3, 4, 11 and 14). Chromosome 11q loss (with frequent parallel loss of chromosomes 3p, 4p and/or 14q) was found exclusively in tumours without MYCN amplification and was significantly associated with poor event-free survival. The 2-year event-free survival rate for 11q LOH cases was 30%, compared to 34% for MYCN-amplified cases and 100% for cases without these abnormalities. While 11q LOH was associated predominantly with advanced-stage disease, 2 cases with low-stage disease and 11q LOH both suffered relapses. We conclude that chromosome 11q loss defines a biologically distinct group of tumours without MYCN amplification that appear to have potential for aggressive metastatic growth. Thus this genetic alteration may be an important new prognostic marker in neuroblastoma. © 2001 Cancer Research Campaign http://www.bjcancer.co

    What future, which technology? On the problem of describing relevant futures.

    Get PDF
    Doing research on future and emerging technologies raises a number of significant ontological and epistemological challenges. The fundamental uncertainty of the future, combined with problems of appropriate descriptions of technology in general, render it difficult to come to an appropriate account of the likely shape and use of future technologies. This paper discusses several streams of research that address this issue, including the question of relevant description and context, interpretive flexibility, affordances of technology, and multi-stability of technological trajectories. The paper proposes that some of these problems may be addressed by using a democratic and participative approach to technology research and development. Participative technology assessment is then discussed as an example of an established way of democratically engaging with technology stakeholders during research and development. The paper concludes by discussing the promises and limitations of such a participative approach with regard to the question of understanding and researching future technologies

    Is small really beautiful? A review of the concept of niches in innovation

    Get PDF
    This article reviews the concept of innovation niches through three categories: strategic niche management (SNM), specialised markets and niches formed as a technology declines. In the literature, innovation niches generate interest from both innovation and marketing perspectives. This review focuses predominately on the former from which the niche types have been adopted and analysed. Mostly, contributions since 1980 have been included, representing the period of academic interest in innovative small firms, while both temporal and locational filters were applied to the study. It is noted that SNM has been proposed as a means to protect potentially useful innovations from full market competition, while specialist niches supply technologies to few customers in more stable environments. Incumbent technologies at the stage of decline may also retreat to niches where they can still remain competitive. Finally, it is suggested that further research on innovation niches would extend our understanding of technology dynamics

    Delivering better outcomes through customer-led project management: the case of the major project BT 21st Century Network in the UK

    Get PDF
    Traditional approaches of major project management take the strategy of selecting a supplier-led prime/systems integrator. Although this strategy pushes a significant amount of risk to the supplier, project performance may suffer due to lower engagement of the customer in the anticipation of potential issues involving a major project. Thus, this research investigates the implications of the customer, as opposed to a selected external supplier, assuming the role of systems/prime integrator, as a Problem Structuring Method (PSM) to better deal with the soft side and uncertainties of the project. A case study approach is conducted on the major project BT 21st Century Network (BT21CN) to demonstrate that customer-led systems integration projects may provide more balance in the relationship and distribution of risks between supplier and customer, having a positive impact on project performance, accelerating the development of BT’s organisational capabilities, and producing better project outcomes in the long term

    Managing operations with people and technology

    No full text
    • …
    corecore