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The paper presents a unified, fully recursive approach to the modelling and forecasting of non-stationary time-series. The basic time-series model, which is based on the well-known ‘component’ or ‘structuraL’ form, is formulated in state-space terms. A novel spectral decomposition procedure, based on the exploitation of recursive smoothing algorithms, is then utilized to simplify the procedures of model identification and estimation. Finally, the fully recursive formulation allows for conventional or self-adaptive implementation of state-space forecasting and seasonal adjustment. Although the paper is restricted to the consideration of univariate time series, the basic approach can be extended to handle explanatory variables or full multivariable (vector) series. 相似文献
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R A Young V Mehra D Sweetser T Buchanan J Clark-Curtiss R W Davis B R Bloom 《Nature》1985,316(6027):450-452
Leprosy, a chronic infectious disease afflicting between 10 and 15 million people, is caused by the obligate intracellular parasite Mycobacterium leprae. Although M. leprae was the first identified bacterial pathogen of man, basic biochemical, immunological, diagnostic and therapeutic investigations have been severely limited because it remains one of the few human pathogens that have not been cultured in vitro. An M. leprae recombinant DNA expression library was constructed to provide a source of genes encoding proteins relevant for such studies. Monoclonal antibodies directed against M. leprae specific antigens have been used to isolate the genes encoding the five most immunogenic protein antigens of the leprosy bacillus. We report here that M. leprae specific epitopes recognized by all of 13 monoclonal antibodies tested were produced by recombinant phage in Escherichia coli. 相似文献
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Marijuana and many of its constituent cannabinoids influence the central nervous system (CNS) in a complex and dose-dependent manner. Although CNS depression and analgesia are well documented effects of the cannabinoids, the mechanisms responsible for these and other cannabinoid-induced effects are not so far known. The hydrophobic nature of these substances has suggested that cannabinoids resemble anaesthetic agents in their action, that is, they nonspecifically disrupt cellular membranes. Recent evidence, however, has supported a mechanism involving a G protein-coupled receptor found in brain and neural cell lines, and which inhibits adenylate cyclase activity in a dose-dependent, stereoselective and pertussis toxin-sensitive manner. Also, the receptor is more responsive to psychoactive cannabinoids than to non-psychoactive cannabinoids. Here we report the cloning and expression of a complementary DNA that encodes a G protein-coupled receptor with all of these properties. Its messenger RNA is found in cell lines and regions of the brain that have cannabinoid receptors. These findings suggest that this protein is involved in cannabinoid-induced CNS effects (including alterations in mood and cognition) experienced by users of marijuana. 相似文献
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Eoin E. Kelly Conor P. Horgan Mary W. McCaffrey Paul Young 《Cellular and molecular life sciences : CMLS》2011,68(2):185-194
Long-term potentiation (LTP) defines persistent increases in neurotransmission strength at synapses that are triggered by
specific patterns of neuronal activity. LTP, the most widely accepted molecular model for learning, is best characterised
at glutamatergic synapses on dendritic spines. In this context, LTP involves increases in dendritic spine size and the insertion
of glutamate receptors into the post-synaptic spine membrane, which together boost post-synaptic responsiveness to neurotransmitters.
In dendrites, the material required for LTP is sourced from an organelle termed the endosomal-recycling compartment (ERC),
which is localised to the base of dendritic spines. When LTP is induced, material derived from the recycling compartment,
which contains α-amino-3-hydroxy-5-methyl-4-isoxazole propionate-type glutamate receptors (AMPARs), is mobilised into dendritic
spines feeding the increased need for receptors and membrane at the spine neck and head. In this review, we discuss the importance
of endosomal-recycling and the role of key proteins which control these processes in the context of LTP. 相似文献
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J. Young 《Systemic Practice and Action Research》2010,23(1):101-113
Representation assumes that those who govern have knowledge of those for whom they govern. It is easy to presume knowledge of the “other”, but as we know this can be based in prejudice, cultural difference, or simply misinformation or simplification. Usually our explorations of this process have focused on populations identified as disadvantaged, disempowered or somehow “non-privileged”. However, the research process outlined here has revealed previously unexplored diversity within a population commonly described as privileged suggesting that good governance requires alertness to presuming to know both the unprivileged and the privileged. The research approach outlined in this paper has used a blend of historical reappraisal and qualitative techniques focusing on a population who have been conceptualized as doubly privileged. This population focus is that of older British; post World War II male migrants in South Australia. These people have been conceptualized as privileged because they are male, and they were part of the preferred ethnic group that Australian politicians and policy makers favoured post WW2. However, review of the historical data and qualitative interviews with some of these men show that the accepted narrative of a homogenous pre-WW2 British origin population is over simplistic. The historical research suggests that the presumption that post WW2 British migrant men were coming into an homogenous, privileging environment in migrating to SA is both ahistorical and crude. Furthermore the belief that post WW2 British migrant men were ethnically homogenous is undermined by the qualitative research, that reveals that their presumed homogeneity is much more fluid and nuanced than dominant conceptualisations have allowed. The impact of core ethnicities that continue to exist and compete in Britain, the social class focus and economic commodification of migrants in the machinations of powerful players in the state of South Australia all confound homogenizing, simplistic knowing of British migrant men in this state. Generically these findings caution social researchers with regard to presuming to know so called “privileged” populations as well as presumed non-privileged groups. 相似文献
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Patrick H. Toy Helen Song He Cathy Kar-Wing Kwong 《复旦学报(自然科学版)》2005,44(5):833-834
1 Introduction Recent years have seen a growing use of polymer-supported reagents by organic chemists in traditional solution-phase synthesis.Of the many reagents supported by polymers available, variations of triphenylphosphine are among the most broadly used. This is because triphenylphosphine is not only a reagent in a wide range of organic reactions~([1]), but it also serves as a ligand in many organometallic reagents~([2]).Most importantly, polymer-supported triphenylphosphine affords the… 相似文献