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91.
Time series forecasting using functional partial least square regression with stochastic volatility,GARCH, and exponential smoothing 下载免费PDF全文
We propose a method for improving the predictive ability of standard forecasting models used in financial economics. Our approach is based on the functional partial least squares (FPLS) model, which is capable of avoiding multicollinearity in regression by efficiently extracting information from the high‐dimensional market data. By using its well‐known ability, we can incorporate auxiliary variables that improve the predictive accuracy. We provide an empirical application of our proposed methodology in terms of its ability to predict the conditional average log return and the volatility of crude oil prices via exponential smoothing, Bayesian stochastic volatility, and GARCH (generalized autoregressive conditional heteroskedasticity) models, respectively. In particular, what we call functional data analysis (FDA) traces in this article are obtained via the FPLS regression from both the crude oil returns and auxiliary variables of the exchange rates of major currencies. For forecast performance evaluation, we compare out‐of‐sample forecasting accuracy of the standard models with FDA traces to the accuracy of the same forecasting models with the observed crude oil returns, principal component regression (PCR), and least absolute shrinkage and selection operator (LASSO) models. We find evidence that the standard models with FDA traces significantly outperform our competing models. Finally, they are also compared with the test for superior predictive ability and the reality check for data snooping. Our empirical results show that our new methodology significantly improves predictive ability of standard models in forecasting the latent average log return and the volatility of financial time series. 相似文献
92.
Jongsung Lee Eunsun Jung Jienny Lee Sungran Huh Young-Soo Kim Yong-Woo Kim Yeong Shik Kim Deokhoon Park 《Cellular and molecular life sciences : CMLS》2010,67(3):467-481
Adipocyte dysfunction is associated with the development of obesity. This study shows that 6-thioinosine inhibits adipocyte
differentiation. The mRNA levels of PPAR γ and C/EBPα, but not C/EBPβ and δ, were reduced by 6-thioinosine. Moreover, the
mRNA levels of PPAR γ target genes (LPL, CD36, aP2, and LXRα) were down-regulated by 6-thioinosine. We also demonstrated that
6-thioinosine inhibits the transactivation activity and the mRNA level of PPAR γ. Additionally, attempts to elucidate a possible
mechanism underlying the 6-thioinosine-mediated effects revealed that 6-thioinosine induced iNOS gene expression without impacting
eNOS expression, and that this was mediated through activation of AP-1, especially, JNK. In addition, 6-thioinosine was found
to operate upstream of MEKK-1 in JNK activation signaling. Taken together, these findings suggest that the inhibition of adipocyte
differentiation by 6-thioinosine occurs primarily through the reduced expression of PPAR γ, which is mediated by upregulation
of iNOS via the activation of JNK. 相似文献
93.
Won H Lee HR Gee HY Mah W Kim JI Lee J Ha S Chung C Jung ES Cho YS Park SG Lee JS Lee K Kim D Bae YC Kaang BK Lee MG Kim E 《Nature》2012,486(7402):261-265
Autism spectrum disorder (ASD) is a group of conditions characterized by impaired social interaction and communication, and restricted and repetitive behaviours. ASD is a highly heritable disorder involving various genetic determinants. Shank2 (also known as ProSAP1) is a multi-domain scaffolding protein and signalling adaptor enriched at excitatory neuronal synapses, and mutations in the human SHANK2 gene have recently been associated with ASD and intellectual disability. Although ASD-associated genes are being increasingly identified and studied using various approaches, including mouse genetics, further efforts are required to delineate important causal mechanisms with the potential for therapeutic application. Here we show that Shank2-mutant (Shank2(-/-)) mice carrying a mutation identical to the ASD-associated microdeletion in the human SHANK2 gene exhibit ASD-like behaviours including reduced social interaction, reduced social communication by ultrasonic vocalizations, and repetitive jumping. These mice show a marked decrease in NMDA (N-methyl-D-aspartate) glutamate receptor (NMDAR) function. Direct stimulation of NMDARs with D-cycloserine, a partial agonist of NMDARs, normalizes NMDAR function and improves social interaction in Shank2(-/-) mice. Furthermore, treatment of Shank2(-/-) mice with a positive allosteric modulator of metabotropic glutamate receptor 5 (mGluR5), which enhances NMDAR function via mGluR5 activation, also normalizes NMDAR function and markedly enhances social interaction. These results suggest that reduced NMDAR function may contribute to the development of ASD-like phenotypes in Shank2(-/-) mice, and mGluR modulation of NMDARs offers a potential strategy to treat ASD. 相似文献
94.
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96.
LI Kai Way CHEN Chin Jung LIN Ching-Hua HSU Yao Wen 《清华大学学报》2006,11(6):712-719
Introduction Slips and falls are common phenomena both in work- places and leisure activities. The coefficient of fric- tion (COF) between footwear and the floor is regarded as the most critical item determining the occurrence of a slip. It is commonly ac… 相似文献
97.
赵俊 《邵阳高等专科学校学报》2000,13(1):45-48
根据足球守门员扑球技术 ,分析了扑“单刀球”技术特点和出击时机 ,提出了对守门员训练方法 相似文献
98.
Jeon J Park SY Chi MH Choi J Park J Rho HS Kim S Goh J Yoo S Choi J Park JY Yi M Yang S Kwon MJ Han SS Kim BR Khang CH Park B Lim SE Jung K Kong S Karunakaran M Oh HS Kim H Kim S Park J Kang S Choi WB Kang S Lee YH 《Nature genetics》2007,39(4):561-565
Rapid translation of genome sequences into meaningful biological information hinges on the integration of multiple experimental and informatics methods into a cohesive platform. Despite the explosion in the number of genome sequences available, such a platform does not exist for filamentous fungi. Here we present the development and application of a functional genomics and informatics platform for a model plant pathogenic fungus, Magnaporthe oryzae. In total, we produced 21,070 mutants through large-scale insertional mutagenesis using Agrobacterium tumefaciens-mediated transformation. We used a high-throughput phenotype screening pipeline to detect disruption of seven phenotypes encompassing the fungal life cycle and identified the mutated gene and the nature of mutation for each mutant. Comparative analysis of phenotypes and genotypes of the mutants uncovered 202 new pathogenicity loci. Our findings demonstrate the effectiveness of our platform and provide new insights on the molecular basis of fungal pathogenesis. Our approach promises comprehensive functional genomics in filamentous fungi and beyond. 相似文献
99.
Effect of prolonged inhibition of histidine decarboxylase on tissue histamine concentrations 总被引:3,自引:0,他引:3
In rats, chronic infusion of alpha-fluoromethyl histidine, a selective irreversible inhibitor of mammalian histidine decarboxylase, caused a marked depletion of histamine in all tissues examined. There were no gross pharmacological effects associated with this depletion. 相似文献
100.
Jeong PY Jung M Yim YH Kim H Park M Hong E Lee W Kim YH Kim K Paik YK 《Nature》2005,433(7025):541-545
Pheromones are cell type-specific signals used for communication between individuals of the same species. When faced with overcrowding or starvation, Caenorhabditis elegans secrete the pheromone daumone, which facilitates communication between individuals for adaptation to adverse environmental stimuli. Daumone signals C. elegans to enter the dauer stage, an enduring and non-ageing stage of the nematode life cycle with distinctive adaptive features and extended life. Because daumone is a key regulator of chemosensory processes in development and ageing, the chemical identification of daumone is important for elucidating features of the daumone-mediated signalling pathway. Here we report the isolation of natural daumone from C. elegans by large-scale purification, as well as the total chemical synthesis of daumone. We present the stereospecific chemical structure of purified daumone, a fatty acid derivative. We demonstrate that both natural and chemically synthesized daumones equally induce dauer larva formation in C. elegans (N2 strain) and certain dauer mutants, and also result in competition between food and daumone. These results should help to elucidate the daumone-mediated signalling pathway, which might in turn influence ageing and obesity research and the development of antinematodal drugs. 相似文献