Computational gene structure prediction, which is valuable for finding new genes and understanding the composition of genomes, plays a very important role in various kinds of genome projects. For eukaryotic gene struc...Computational gene structure prediction, which is valuable for finding new genes and understanding the composition of genomes, plays a very important role in various kinds of genome projects. For eukaryotic gene structures, however, the prediction accuracy of existing methods is still limited. This paper presents a method of pre-dicting eukaryotic gene structures based on multilevel opti-mization. The complicated problem of predicting gene structure in eukaryotic DNA sequence containing multiple genes can be decomposed into a series of sub-problems at several levels with decreasing complexity, including the gene level (single-exon gene, multi-exon gene), the element level (exon, intron, etc.), and the feature level (functional site sig-nals, codon usage preference, etc.). On the basis of this de-composition, a multilevel model for the prediction of complex gene structures is created by a multilevel optimization proc-ess, in which the models dealing with sub-problems at low complexity level are first optimized respectively, and then optimally combined together to form models for those sub-problems at higher complexity level. Based on the multi-level model, a dynamic programming algorithm is designed to search for optimal gene structures from DNA sequences, and a new program GeneKey (1.0) for the prediction of eu-karyotic gene structures is developed. Testing results with widely used datasets demonstrate that the prediction accura-cies of GeneKey (1.0) at the nucleotide level, exon level and gene level are all higher than that of the well known program GENSCAN. A web server of GeneKey(1.0) is available at http://infosci.hust.edu.展开更多
English, a second language for most people in the world,has increasingly become the international language for businessand commerce, science and technology, and internationalrelations and diplomacy. Therefore as child...English, a second language for most people in the world,has increasingly become the international language for businessand commerce, science and technology, and internationalrelations and diplomacy. Therefore as children will soon beexpected to thrive in the global environment of the 21st century,they are forced or encouraged to start second language learning atan early age. This brings challenge to educators, because younglearners are definitely different from adults or adolescent learnersin many aspects. In dealing with younger learners, educatorsshould provide an optimal learning environment, which at leastincludes appropriate linguistic input and appropriate languageinstruction, based on the cognitive and psychologicalcharacteristics of young learners. This paper will review some theoretical assumptions whichhave implications for SLA of young learners, consider thespecific features of young learners, and provide some suggestionsfor language instruction and material design.展开更多
文摘Computational gene structure prediction, which is valuable for finding new genes and understanding the composition of genomes, plays a very important role in various kinds of genome projects. For eukaryotic gene structures, however, the prediction accuracy of existing methods is still limited. This paper presents a method of pre-dicting eukaryotic gene structures based on multilevel opti-mization. The complicated problem of predicting gene structure in eukaryotic DNA sequence containing multiple genes can be decomposed into a series of sub-problems at several levels with decreasing complexity, including the gene level (single-exon gene, multi-exon gene), the element level (exon, intron, etc.), and the feature level (functional site sig-nals, codon usage preference, etc.). On the basis of this de-composition, a multilevel model for the prediction of complex gene structures is created by a multilevel optimization proc-ess, in which the models dealing with sub-problems at low complexity level are first optimized respectively, and then optimally combined together to form models for those sub-problems at higher complexity level. Based on the multi-level model, a dynamic programming algorithm is designed to search for optimal gene structures from DNA sequences, and a new program GeneKey (1.0) for the prediction of eu-karyotic gene structures is developed. Testing results with widely used datasets demonstrate that the prediction accura-cies of GeneKey (1.0) at the nucleotide level, exon level and gene level are all higher than that of the well known program GENSCAN. A web server of GeneKey(1.0) is available at http://infosci.hust.edu.
文摘English, a second language for most people in the world,has increasingly become the international language for businessand commerce, science and technology, and internationalrelations and diplomacy. Therefore as children will soon beexpected to thrive in the global environment of the 21st century,they are forced or encouraged to start second language learning atan early age. This brings challenge to educators, because younglearners are definitely different from adults or adolescent learnersin many aspects. In dealing with younger learners, educatorsshould provide an optimal learning environment, which at leastincludes appropriate linguistic input and appropriate languageinstruction, based on the cognitive and psychologicalcharacteristics of young learners. This paper will review some theoretical assumptions whichhave implications for SLA of young learners, consider thespecific features of young learners, and provide some suggestionsfor language instruction and material design.
