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排序方式: 共有85条查询结果,搜索用时 125 毫秒
61.
This paper proposes and implements a new methodology for forecasting time series, based on bicorrelations and cross‐bicorrelations. It is shown that the forecasting technique arises as a natural extension of, and as a complement to, existing univariate and multivariate non‐linearity tests. The formulations are essentially modified autoregressive or vector autoregressive models respectively, which can be estimated using ordinary least squares. The techniques are applied to a set of high‐frequency exchange rate returns, and their out‐of‐sample forecasting performance is compared to that of other time series models. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
62.
Charles S. Henry Stephen J. Brooks James B. Johnson Atsushi Mochizuki Alinaghi Mirmoayedi Peter Duelli 《Journal of Natural History》2018,52(25-26):1603-1635
Chrysoperla shahrudensis sp. nov. is discovered in northern Iran, co-occurring with at least five other cryptic species of the Chrysoperla carnea-group. It is distinguished by the volley period and tonality of its courtship duetting song. Another Asian species from alpine meadows of northern Kyrgyzstan, previously C. ‘adamsi-K’ but here named Chrysoperla bolti sp. nov., has a song distinct from but convergent with both C. shahrudensis and North American Chrysoperla adamsi. Coordinated duets can be established in the laboratory between individuals of C. shahrudensis and recorded songs of either C. bolti or C. adamsi. Such functional song equivalence in distinct allopatric species suggests that repeated episodes of parallel speciation can drive the origin of cryptic species diversity in lacewings. Morphology, life history, and ecology of larvae and adults of C. shahrudensis and C. bolti are then formally described. Adding C. shahrudensis to a large mitochondrial DNA data set for ≈ 21 species shows it to be similar to neither C. adamsi nor C. bolti, further supporting independent, convergent evolution of song rather than song similarity due to relationship. Although C. bolti and C. shahrudensis are both from Asia and share some basic temporal song features, the two taxa are distinct, allopatric biological species.
www.zoobank.org/urn:lsid:zoobank.org:pub:D9B7BDC9-6C09-468B-A6B-D378628EC557 相似文献
63.
Xu B Roos JL Dexheimer P Boone B Plummer B Levy S Gogos JA Karayiorgou M 《Nature genetics》2011,43(9):864-868
Despite its high heritability, a large fraction of individuals with schizophrenia do not have a family history of the disease (sporadic cases). Here we examined the possibility that rare de novo protein-altering mutations contribute to the genetic component of schizophrenia by sequencing the exomes of 53 sporadic cases, 22 unaffected controls and their parents. We identified 40 de novo mutations in 27 cases affecting 40 genes, including a potentially disruptive mutation in DGCR2, a gene located in the schizophrenia-predisposing 22q11.2 microdeletion region. A comparison to rare inherited variants indicated that the identified de novo mutations show a large excess of non-synonymous changes in schizophrenia cases, as well as a greater potential to affect protein structure and function. Our analyses suggest a major role for de novo mutations in schizophrenia as well as a large mutational target, which together provide a plausible explanation for the high global incidence and persistence of the disease. 相似文献
64.
Stoetzel C Laurier V Davis EE Muller J Rix S Badano JL Leitch CC Salem N Chouery E Corbani S Jalk N Vicaire S Sarda P Hamel C Lacombe D Holder M Odent S Holder S Brooks AS Elcioglu NH Silva ED Da Silva E Rossillion B Sigaudy S de Ravel TJ Lewis RA Leheup B Verloes A Amati-Bonneau P Mégarbané A Poch O Bonneau D Beales PL Mandel JL Katsanis N Dollfus H 《Nature genetics》2006,38(5):521-524
Bardet-Biedl syndrome (BBS) is a genetically heterogeneous ciliopathy. Although nine BBS genes have been cloned, they explain only 40-50% of the total mutational load. Here we report a major new BBS locus, BBS10, that encodes a previously unknown, rapidly evolving vertebrate-specific chaperonin-like protein. We found BBS10 to be mutated in about 20% of an unselected cohort of families of various ethnic origins, including some families with mutations in other BBS genes, consistent with oligogenic inheritance. In zebrafish, mild suppression of bbs10 exacerbated the phenotypes of other bbs morphants. 相似文献
65.
吴雄武 《南京工业大学学报(自然科学版)》2006,28(1)
采用新近提出的迷向周期和方法(IPS),结合自导Lang evin动态模拟,模拟研究9余肽折褶成β簮结构的情况,表明了该结构与NMR观察到的基本一致,而Ewald模拟由于是强烈的镜像相互作用会产生构型偏差,获得致密构型的几率增大,表明IPS方法更适合于周期边界条件的模拟. 相似文献
66.
Karnoub AE Dash AB Vo AP Sullivan A Brooks MW Bell GW Richardson AL Polyak K Tubo R Weinberg RA 《Nature》2007,449(7162):557-563
Mesenchymal stem cells have been recently described to localize to breast carcinomas, where they integrate into the tumour-associated stroma. However, the involvement of mesenchymal stem cells (or their derivatives) in tumour pathophysiology has not been addressed. Here, we demonstrate that bone-marrow-derived human mesenchymal stem cells, when mixed with otherwise weakly metastatic human breast carcinoma cells, cause the cancer cells to increase their metastatic potency greatly when this cell mixture is introduced into a subcutaneous site and allowed to form a tumour xenograft. The breast cancer cells stimulate de novo secretion of the chemokine CCL5 (also called RANTES) from mesenchymal stem cells, which then acts in a paracrine fashion on the cancer cells to enhance their motility, invasion and metastasis. This enhanced metastatic ability is reversible and is dependent on CCL5 signalling through the chemokine receptor CCR5. Collectively, these data demonstrate that the tumour microenvironment facilitates metastatic spread by eliciting reversible changes in the phenotype of cancer cells. 相似文献
67.
68.
Replicating genotype-phenotype associations 总被引:1,自引:0,他引:1
NCI-NHGRI Working Group on Replication in Association Studies Chanock SJ Manolio T Boehnke M Boerwinkle E Hunter DJ Thomas G Hirschhorn JN Abecasis G Altshuler D Bailey-Wilson JE Brooks LD Cardon LR Daly M Donnelly P Fraumeni JF Freimer NB Gerhard DS Gunter C Guttmacher AE Guyer MS Harris EL Hoh J Hoover R Kong CA Merikangas KR Morton CC Palmer LJ Phimister EG Rice JP Roberts J Rotimi C Tucker MA Vogan KJ Wacholder S Wijsman EM Winn DM Collins FS 《Nature》2007,447(7145):655-660
69.
Sebaihia M Wren BW Mullany P Fairweather NF Minton N Stabler R Thomson NR Roberts AP Cerdeño-Tárraga AM Wang H Holden MT Wright A Churcher C Quail MA Baker S Bason N Brooks K Chillingworth T Cronin A Davis P Dowd L Fraser A Feltwell T Hance Z Holroyd S Jagels K Moule S Mungall K Price C Rabbinowitsch E Sharp S Simmonds M Stevens K Unwin L Whithead S Dupuy B Dougan G Barrell B Parkhill J 《Nature genetics》2006,38(7):779-786
We determined the complete genome sequence of Clostridium difficile strain 630, a virulent and multidrug-resistant strain. Our analysis indicates that a large proportion (11%) of the genome consists of mobile genetic elements, mainly in the form of conjugative transposons. These mobile elements are putatively responsible for the acquisition by C. difficile of an extensive array of genes involved in antimicrobial resistance, virulence, host interaction and the production of surface structures. The metabolic capabilities encoded in the genome show multiple adaptations for survival and growth within the gut environment. The extreme genome variability was confirmed by whole-genome microarray analysis; it may reflect the organism's niche in the gut and should provide information on the evolution of virulence in this organism. 相似文献
70.
Pharmacological manipulation of L-carnitine transport into L6 cells with stable overexpression of human OCTN2 总被引:1,自引:0,他引:1
Todesco L Bur D Brooks H Török M Landmann L Stieger B Krähenbühl S 《Cellular and molecular life sciences : CMLS》2008,65(10):1596-1608
The high-affinity Na+-dependent carnitine transporter OCTN2 (SLC22A5) has a high renal expression and reabsorbs most filtered carnitine. To gain more insight into substrate specificity of OCTN2, we overexpressed hOCTN2 in L6 cells and characterized the structural requirements of substances acting as human OCTN2 (hOCTN2) inhibitors. A 1905-bp fragment containing the hOCTN2 complete coding sequence was introduced into the pWpiresGFP vector, and L6 cells were stably transduced using a lentiviral system. The transduced L6 cells revealed increased expression of hOCTN2 on the mRNA, protein and functional levels. Structural requirements for hOCTN2 inhibition were predicted in silico and investigated in vitro. Essential structural requirements for OCTN2 inhibition include a constantly positively charged nitrogen atom and a carboxyl, nitrile or ester group connected by a 2-4-atom linker. Our cell system is suitable for studying in vitro interactions with OCTN2, which can subsequently be investigated in vivo. 相似文献