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81.
Peter Exterkate Dick Van Dijk Christiaan Heij Patrick J. F. Groenen 《Journal of forecasting》2013,32(3):193-214
This paper compares various ways of extracting macroeconomic information from a data‐rich environment for forecasting the yield curve using the Nelson–Siegel model. Five issues in extracting factors from a large panel of macro variables are addressed; namely, selection of a subset of the available information, incorporation of the forecast objective in constructing factors, specification of a multivariate forecast objective, data grouping before constructing factors, and selection of the number of factors in a data‐driven way. Our empirical results show that each of these features helps to improve forecast accuracy, especially for the shortest and longest maturities. Factor‐augmented methods perform well in relatively volatile periods, including the crisis period in 2008–9, when simpler models do not suffice. The macroeconomic information is exploited best by partial least squares methods, with principal component methods ranking second best. Reductions of mean squared prediction errors of 20–30% are attained, compared to the Nelson–Siegel model without macro factors. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
82.
Cross-modal interactions between visual understanding and linguistic processing substantially contribute to the remarkable robustness of human language processing.We argue that the formation of cross-modal referential links is a prerequisite for the occurrence of cross-modal interactions between vision and language.In this paper we examine a computational model for a cross-modal reference formation with respect to its robustness against conceptual underspecification in the visual modality.This investigation is motivated by the fact that natural systems are well capable of establishing a cross-modal reference between modalities with different degrees of conceptual specification.In the investigated model,conceptually underspecified context information continues to drive the syntactic disambiguation of verb-centered syntactic ambiguities as long as the visual context contains the situation arity information of the visual scene. 相似文献
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85.
Proteome survey reveals modularity of the yeast cell machinery 总被引:4,自引:0,他引:4
Gavin AC Aloy P Grandi P Krause R Boesche M Marzioch M Rau C Jensen LJ Bastuck S Dümpelfeld B Edelmann A Heurtier MA Hoffman V Hoefert C Klein K Hudak M Michon AM Schelder M Schirle M Remor M Rudi T Hooper S Bauer A Bouwmeester T Casari G Drewes G Neubauer G Rick JM Kuster B Bork P Russell RB Superti-Furga G 《Nature》2006,440(7084):631-636
Protein complexes are key molecular entities that integrate multiple gene products to perform cellular functions. Here we report the first genome-wide screen for complexes in an organism, budding yeast, using affinity purification and mass spectrometry. Through systematic tagging of open reading frames (ORFs), the majority of complexes were purified several times, suggesting screen saturation. The richness of the data set enabled a de novo characterization of the composition and organization of the cellular machinery. The ensemble of cellular proteins partitions into 491 complexes, of which 257 are novel, that differentially combine with additional attachment proteins or protein modules to enable a diversification of potential functions. Support for this modular organization of the proteome comes from integration with available data on expression, localization, function, evolutionary conservation, protein structure and binary interactions. This study provides the largest collection of physically determined eukaryotic cellular machines so far and a platform for biological data integration and modelling. 相似文献
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87.
Patrick J. Shaw Bin Qu Markus Hoth Stefan Feske 《Cellular and molecular life sciences : CMLS》2013,70(15):2637-2656
Calcium (Ca2+) influx is required for the activation and function of all cells in the immune system. It is mediated mainly by store-operated Ca2+ entry (SOCE) through Ca2+ release-activated Ca2+ (CRAC) channels located in the plasma membrane. CRAC channels are composed of ORAI proteins that form the channel pore and are activated by stromal interaction molecules (STIM) 1 and 2. Located in the membrane of the endoplasmic reticulum, STIM1 and STIM2 have the dual function of sensing the intraluminal Ca2+ concentration in the ER and to activate CRAC channels. A decrease in the ER’s Ca2+ concentration induces STIM multimerization and translocation into puncta close to the plasma membrane where they bind to and activate ORAI channels. Since the identification of ORAI and STIM genes as the principal mediators of CRAC channel function, substantial advances have been achieved in understanding the molecular regulation and physiological role of CRAC channels in cells of the immune system and other organs. In this review, we discuss the mechanisms that regulate CRAC channel function and SOCE, the role of recently identified proteins and mechanisms that modulate the activation of ORAI/STIM proteins and the consequences of CRAC channel dysregulation for lymphocyte function and immunity. 相似文献
88.
Gissen P Johnson CA Morgan NV Stapelbroek JM Forshew T Cooper WN McKiernan PJ Klomp LW Morris AA Wraith JE McClean P Lynch SA Thompson RJ Lo B Quarrell OW Di Rocco M Trembath RC Mandel H Wali S Karet FE Knisely AS Houwen RH Kelly DA Maher ER 《Nature genetics》2004,36(4):400-404
ARC syndrome (OMIM 208085) is an autosomal recessive multisystem disorder characterized by neurogenic arthrogryposis multiplex congenita, renal tubular dysfunction and neonatal cholestasis with bile duct hypoplasia and low gamma glutamyl transpeptidase (gGT) activity. Platelet dysfunction is common. Affected infants do not thrive and usually die in the first year of life. To elucidate the molecular basis of ARC, we mapped the disease to a 7-cM interval on 15q26.1 and then identified germline mutations in the gene VPS33B in 14 kindreds with ARC. VPS33B encodes a homolog of the class C yeast vacuolar protein sorting gene, Vps33, that contains a Sec1-like domain important in the regulation of vesicle-to-target SNARE complex formation and subsequent membrane fusion. 相似文献
89.
X-linked inheritance of Fanconi anemia complementation group B 总被引:20,自引:0,他引:20
Meetei AR Levitus M Xue Y Medhurst AL Zwaan M Ling C Rooimans MA Bier P Hoatlin M Pals G de Winter JP Wang W Joenje H 《Nature genetics》2004,36(11):1219-1224
Fanconi anemia is an autosomal recessive syndrome characterized by diverse clinical symptoms, hypersensitivity to DNA crosslinking agents, chromosomal instability and susceptibility to cancer. Fanconi anemia has at least 11 complementation groups (A, B, C, D1, D2, E, F, G, I, J, L); the genes mutated in 8 of these have been identified. The gene BRCA2 was suggested to underlie complementation group B, but the evidence is inconclusive. Here we show that the protein defective in individuals with Fanconi anemia belonging to complementation group B is an essential component of the nuclear protein 'core complex' responsible for monoubiquitination of FANCD2, a key event in the DNA-damage response pathway associated with Fanconi anemia and BRCA. Unexpectedly, the gene encoding this protein, FANCB, is localized at Xp22.31 and subject to X-chromosome inactivation. X-linked inheritance has important consequences for genetic counseling of families with Fanconi anemia belonging to complementation group B. Its presence as a single active copy and essentiality for a functional Fanconi anemia-BRCA pathway make FANCB a potentially vulnerable component of the cellular machinery that maintains genomic integrity. 相似文献
90.
Mutations in the desmosomal protein plakophilin-2 are common in arrhythmogenic right ventricular cardiomyopathy 总被引:20,自引:0,他引:20
Gerull B Heuser A Wichter T Paul M Basson CT McDermott DA Lerman BB Markowitz SM Ellinor PT MacRae CA Peters S Grossmann KS Drenckhahn J Michely B Sasse-Klaassen S Birchmeier W Dietz R Breithardt G Schulze-Bahr E Thierfelder L 《Nature genetics》2004,36(11):1162-1164
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is associated with fibrofatty replacement of cardiac myocytes, ventricular tachyarrhythmias and sudden cardiac death. In 32 of 120 unrelated individuals with ARVC, we identified heterozygous mutations in PKP2, which encodes plakophilin-2, an essential armadillo-repeat protein of the cardiac desmosome. In two kindreds with ARVC, disease was incompletely penetrant in most carriers of PKP2 mutations. 相似文献