Lexicalization and Grammar Development

In this paper we present a fully lexicalized grammar formalism as a particularly attractive framework for the specification of natural language grammars. We discuss in detail Feature-based, Lexicalized Tree Adjoining Grammars (FB-LTAGs), a representative of the class of lexicalized grammars. We illustrate the advantages of lexicalized grammars in various contexts of natural language processing, ranging from wide-coverage grammar development to parsing and machine translation. We also present a method for compact and efficient representation of lexicalized trees.Comment: ps file. English w/ German abstract. 10 page

Male-specific DNA markers from African catfish (Clarias gariepinus)

We searched for sex-specific DNA sequences in the male and female genomes of African catfish, Clarias gariepinus (Burchell, 1822) by comparative random amplified polymorphic DNA (RAPD) assays performed on pooled DNA samples. Two sex-linked RAPD markers were identified from the male DNA pool and confirmed on individual samples, showing good agreement with phenotypic sex. Both markers were isolated, cloned and characterized. The first marker (CgaY1) was nearly 2.6 kb long, while the length of second one (CgaY2) was 458 bp. Southern blot analysis with a CgaY1 probe showed strong hybridizing fragments only in males and not in females under stringent conditions, indicating the presence of multiple copies of CgaY1 in the male genome. When tested by zoo blot on the genomes of two closely related species from the Clariidae family, CgaY1 hybridized to the DNA of Heterobranchus longifilis and generated a faint male-specific band at low stringency. CgaY2 produced similar hybridization pattern in both sexes of C. gariepinus, C. macrocephalus and H. longifilis. Specific primers were designed to the sequences and the markers were amplified in multiplex PCR reactions together with a control band common to all individuals. This allowed for rapid, molecular sexing of the species on the basis of a simple three band (male) versus one band (female) pattern. According to our knowledge these are the first sex-specific DNA markers isolated from a siluroid fish species

Status of the XTAG System

XTAG is an ongoing project to develop a wide-coverage grammar for English, based on the Feature-based Lexicalized Tree Adjoining Grammar (FB-LTAG) formalism. The XTAG system integrates a morphological analyzer, an N-best part-of-speech tagger, an Early-style parser and an X-window interface, along with a wide-coverage grammar for English developed using the system. This system serves as a linguist's workbench for developing FB-LTAG specifications. This paper presents a description of and recent improvements to the various components of the XTAG system. It also presents the recent performance of the wide-coverage grammar on various corpora and compares it against the performance of other wide-coverage and domain-specific grammars

XTAG System -- A Wide Coverage Grammar for English

This paper presents the XTAG system, a grammar development tool based on the Tree Actioining Grammar (IG) formalism that includes a wide-coverage syntactic grammar' or English. The various components of the system are discussed and preliminary evaluation results fi'om the parsing of various corpora are given. Results from the comparison of XTAG agaiust the IBM statistical parser' and the Alvey Natural Language Tool parser are also given

Genetic analysis of two common carp broodstocks by RAPD and microsatellite markers

The whole broodstock of two Hungarian common carp farms—80 and 196 individuals—was analyzed by using random amplified polymorphic DNA (RAPD) assay and microsatellite analysis. Ten polymorphic RAPD markers and four microsatellites were selected to genotype both of the stocks. As expected, microsatellite analysis revealed more detailed information on genetic diversities than RAPD assay. Results obtained with both types of DNA markers showed lack of major differences between the genetic structure of the two stocks: heterozygosity values and allele frequencies were very similar. Dendrograms created from both sets of data did not show grouping of individuals according to stocks. Genotypes from the two stocks were also compared to those from a limited number of samples collected from other hatcheries and two rivers. Allele frequencies in the groups were similar, with the exception of wild carps. An interesting observation was that three private microsatellite alleles were found in the eight wild carp individuals, compared to the seven detected in the rest of the samples tested (372 individuals)