875 resultados para XY CHAIN
Resumo:
In an earlier paper [Journal of Mathematical Economics, 37 (2002) 17-38], we proved that if a preference relation on a commodity space is non-representable by a real-valued function then that chain is necessarily a long chain, a planar chain, an Aronszajn-like chain or a Souslin chain. In this paper, we study the class of planar chains, the simplest example of which is the Debreu chain (R-2, <(l)). (C) 2002 Elsevier Science B.V. All rights reserved.
Resumo:
We examine the potential impact of interconnectivity of value chain partnerships through electronic means (e-business practices) on the management of Public Sector Agriculture R&D in Australia. We review the changing forms of managing research and development, the forces driving these changes, and R&D processes that are theoretically consistent with the move towards value chain involvement and the increase in active constituents in Public Sector Agriculture R&D. We then explore the potential of emerging e-business models to change the patterns of inter-connectivity, speed and omnipresence of partners in the value chain. Three e-business R&D management practices are identified that provide the prerequisite flexibility necessary to take advantage of opportunistic markets. These R&D business practices are: compressing R&D to reduce time to market, fostering co-development to enter a market at the last moment and building flexible products that allow adjustment at the last possible moment. Some fundamental reallocation of existing resources will be required to meet these markets. Implications of these e-business practices for R&D management are discussed.
Resumo:
The study of viral-based processes is hampered by (a) their complex, transient nature, (b) the instability of products, and (c) the lack of accurate diagnostic assays. Here, we describe the use of real-time quantitative polymerase chain reaction to characterize baculoviral infection. Baculovirus DNA content doubles every 1.7 h from 6 h post-infection until replication is halted at the onset of budding. No dynamic equilibrium exists between replication and release, and the kinetics are independent of the cell density at the time of infection. No more than 16% of the intracellular virus copies bud from the cell. (C) 2002 John Wiley & Sons, Inc. Biotechnol Bioeng 77: 476-480, 2002; DOI 10.1002/bit.10126.
Resumo:
The orthodoxy of supply chain management (SCM) emphasises competitive advantage through increased operational efficiency and market responsiveness from production and distribution processes into the hands of consumers. It anticipates that future competition will be between chains rather than between firms. While well established in other industry sectors, the SCM concept is newly developed in the Australian agri-food sector. Critical review of the concept has identified key issues of power among channel members, processes of chain initiation and innovation, and the inability of SCM to offer a viable business strategy for some firms. Building on those insights, this paper examines the supply chain concept for horticulture. Horticultural products are characterised by perishability, heterogeneity and lags in production response to market signals. Producers’ profits are vulnerable to quantity, timing of supply and product specification. Many supply chains in smaller industries are loose, fragmented, interwoven, unstable and unique! Firms operating within these environments need an astute understanding of the chains, the hierarchy of channel members and their relative position. Effective business strategies – for individual firms and supply chains - need to be developed and redeveloped to accommodate the dynamic nature of horticulture. Two case studies are discussed as contributions to this early stage of the theoretical development of supply chain management. The SCM concept also has implications for horticultural researchers, involving a wider range of industry stakeholders, technical problems and research skills. As for business management, the usefulness of the concept will depend on its capacity to increase responsiveness to customers’ preferences and customer value.
Resumo:
Members of the Culex sitiens subgroup are important vectors of arboviruses, including Japanese encephalitis virus, Murray Valley encephalitis virus and Ross River virus. Of the eight described species, Cx. annulirostris Skuse, Cx. sitiens Wiedemann, and Cx. palpalis Taylor appear to be the most abundant and widespread throughout northern Australia and Papua New Guinea (PNG). Recent investigations using allozymes have shown this subgroup to contain cryptic species that possess overlapping adult morphology. We report the development of a polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) procedure that reliably separates these three species. This procedure utilizes the sequence variation in the ribosomal DNA ITS1 and demonstrates species-specific PCR-RFLP profiles from both colony and field collected material. Assessment of the consistency of this procedure was undertaken on mosquitoes sampled from a wide geographic area including Australia, PNG, and the Solomon Islands. Overlapping adult morphology was observed for Cx. annulirostris and Cx. palpalis in both northern Queensland and PNG and for all three species at one site in northwest Queensland.
Resumo:
Antibodies have the potential to be therapeutic reagents for malaria. Here we describe the production of a novel phage antibody display library against the C-terminal 19 kDa region of the Plasmodium yoelii YM merozoite surface protein-1 (MSP1(19)). In vivo studies against homologous lethal malaria challenge show an anti-parasite effect in a dose dependent manner, and analysis by plasmon resonance indicates binding to the antigen is comparable to the binding of a protective monoclonal antibody. The data support the lack of a need for any antibody Fc-related function and hold great significance for the development of a therapeutic reagent for malaria. (C) 2002 Elsevier Science Ltd. All rights reserved.
Resumo:
The role that Epstein-Barr virus plays in nasopharyngeal carcinoma and Burkitt's lymphoma has been under intense study for many years. With only a limited set of viral genes being expressed in these tumours it has been difficult to understand how the virus could cause/aid in the generation of the tumours. In 1997 a paper was published by Fries et al. [Fries et al. (1997) Identification of a novel protein encoded by the BamHI A region of the Epstein-Barr virus. J Virol 71: 2765-2771.] in which a rabbit serum was generated and used to identify protein products (RK-BARF0) encoded from the BamH1 A region of EBV. In this paper we have isolated these proteins from two-dimensional gels and identified them, using mass spectrometry, as components of HLA DR.
Resumo:
Objective To develop and validate specific, sensitive and rapid diagnostic tests using RT-PCR for the detection of Ross River virus (RRV), Kunjin virus (KV) and Murray Valley encephalitis virus (MVEV) infections in horses. Methods Primer sets based on nucleotide sequence encoding the envelope glycoprotein E2 of RRV and on the nonstructural protein 5 (NS5) of KV and MVEV were designed and used in single round PCRs to test for the respective viruses in infected cell cultures and, in the case of RRV, in samples of horse blood and synovial fluid. Results The primer pairs designed for each of the three viruses amplified a product of expected size from prototype viruses that were grown in cell culture. The identity of each of the products was confirmed by nucleotide sequencing indicating that in the context used the RT-PCRs were specific. RRV was detected in serums from 8 horses for which there were clinical signs consistent with RRV infection such that an acute-phase serum sample was taken and submitted for RRV serology testing. The RRV RT-PCR was analytically sensitive in that it was estimated to detect as little as 50 TCID50 of RRV per mL of serum and was specific in that the primer pairs did not amplify other products from the 8 serum samples. The RRV primers also detected virus in three independent mosquito pools known to contain RRV by virus isolation in cell culture. Samples from horses suspected to be infected with KV and MVEV were not available. Conclusion Despite much anecdotal and serological evidence for infection of horses with RRV actual infection and associated clinical disease are infrequently confirmed. The availability of a specific and analytically sensitive RT-PCR for the detection of RRV provides additional opportunities to confirm the presence of this virus in clinical samples. The RTPCR primers for the diagnosis of KV and MVEV infections were shown to be specific for cell culture grown viruses but the further validation of these tests requires the availability of appropriate clinical samples from infected horses.
Resumo:
Purpose: For treatment of various knee disorders, muscles are trained in open or closed kinetic chain tasks. Coordination between the heads of the quadriceps muscle is important for stability and optimal joint loading for both the tibiofemoral and the patellofemoral joint. The aim of this study was to examine whether the quadriceps femoris muscles are activated differently in open versus closed kinetic chain tasks. Methods: Ten healthy men and women (mean age 28.5 +/- 0.7) extended the knees isometrically in open and closed kinetic chain tasks in a reaction time paradigm using moderate force. Surface electromyography (EMG) recordings were made from four different parts of the quadriceps muscle. The onset and amplitude of EMG and force data were measured. Results: In closed chain knee extension, the onset of EMG activity of the four different muscle portions of the quadriceps was more simultaneous than in the open chain. In open chain, rectus femoris (RF) had the earliest EMG onset while vastus medialis obliquus was activated last (7 +/- 13 ms after RF EMG onset) and with smaller amplitude (40 +/- 30% of maximal voluntary contraction (MVC)) than in closed chain (46 +/- 43% MVC). Conclusions: Exercise in closed kinetic chain promotes more balanced initial quadriceps activation than does exercise in open kinetic chain. This may be of importance in designing training programs aimed toward control of the patellofemoral joint.
Resumo:
Conventional kinesin is a microtubule-based molecular motor involved in the transport of membranous and non-membranous cargoes. The kinesin holoenzyme exists as a heterotetramer, consisting of two heavy chain and two light chain subunits. It is thought that one function of the light chains is to interact with the cargo. Alternative splicing of kinesin light chain pre-mRNA has been observed in lower organisms, although evidence for alternative splicing of the human gene has not been reported. We have identified 19 variants of the human KNS2 gene (KLC1) that are generated by alternative splicing of downstream exons, but calculate that KNS2 has the potential to produce 285919 spliceforms. Corresponding spliceforms of the mouse KLC1 gene were also identified. The alternative exons are all located 3' of exon 12 and the novel spliceforms produce both alternative carboxy termini and alternative 3' untranslated regions. The observation of multiple light chain isoforms is consistent with their proposed role in specific cargo attachment.
Resumo:
Nos últimos anos, a economia mundial e a economia brasileira têm sofrido mudanças importantes. Fusões, aquisições e alianças estratégicas têm se multiplicado. Parte considerável destas mudanças relaciona-se com profundas alterações nos sistemas de valores de todos os segmentos industriais. A busca da competitividade relaciona-se cada vez mais com a busca do ótimo sistêmico além das fronteiras da empresa. Neste contexto, a administração logística ganha nova dimensão, envolvendo a integração de todas as atividades ao longo da cadeia de valores e do sistema de valores, das matérias-primas ao cliente final. O objetivo deste trabalho é (re)situar a administração logística no contexto de mudanças, enfatizando a metodologia da gestão da cadeia de demanda (supply chain management).