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The General Agreement on Tariffs and Trade (1994) (GATT) is premised on the elimination of all barriers to trade in goods. Contrary to this approach, Article XX of the GATT authorises the circumvention of this imperative. More specifically, Article XX(j) of the GATT essentially provides that GATT contracting parties are authorised to promulgate measures that are "essential" to the acquisition of products in general or local short supply. This invariably means that only measures that are "essential" will satisfy the "necessity test" contemplated under Article XX(j). The Appellate Body Report, India - Certain Measures Relating to Solar Cells and Solar Modules is the first World Trade Organisation case to elaborate on the "necessity test" of Article XX(j) of the GATT. This paper seeks to evaluate the Appellate Body's findings on the "necessity test" of Article XX(j).

The General Agreement on Tariffs and Trade (1994) (GATT) is premised on the elimination of all barriers to trade in goods. Contrary to this approach, Article XX of the GATT authorises the circumvention of this imperative. More specifically, Article XX(j) of the GATT essentially provides that GATT contracting parties are authorised to promulgate measures that are "essential" to the acquisition of products in general or local short supply. This invariably means that only measures that are "essential" will satisfy the "necessity test" contemplated under Article XX(j). The Appellate Body Report, India - Certain Measures Relating to Solar Cells and Solar Modules is the first World Trade Organisation case to elaborate on the "necessity test" of Article XX(j) of the GATT. This paper seeks to evaluate the Appellate Body's findings on the "necessity test" of Article XX(j). [ABSTRACT FROM AUTHOR]

DnaE is an alpha subunit of the tripartite protein complex of DNA polymerase III that is responsible for the replication of bacterial genome. The dnaE gene is often duplicated in many bacteria, and the duplicated dnaE gene was reported dispensable for cell survivals and error-prone in DNA replication in a mystery. In this study, we found that all sequenced myxobacterial genomes possessed two dnaE genes. The duplicate dnaE genes were both highly conserved but evolved divergently, suggesting their importance in myxobacteria. Using Myxococcus xanthus DK1622 as a model, we confirmed that dnaE1 (MXAN_5844) was essential for cell survival, while dnaE2 (MXAN_3982) was dispensable and encoded an error-prone enzyme for replication. The deletion of dnaE2 had small effects on cellular growth and social motility, but significantly decreased the development and sporulation abilities, which could be recovered by the complementation of dnaE2. The expression of dnaE1 was always greatly higher than that of dnaE2 in either the growth or developmental stage. However, overexpression of dnaE2 could not make dnaE1 deletable, probably due to their protein structural and functional divergences. The dnaE2 overexpression not only improved the growth, development and sporulation abilities, but also raised the genome mutation rate of M. xanthus. We argued that the low-expressed error-prone DnaE2 played as a balancer for the genome mutation rates, ensuring low mutation rates for cell adaptation in new environments but avoiding damages from high mutation rates to cells. [ABSTRACT FROM AUTHOR]

The three standard products (the Cartesian, the direct and the strong product) of undirected graphs have been repeatedly studied, unique prime factor decomposition (PFD) is known and polynomial time algorithms have been established for determining the prime factors. For directed graphs, unique PFD results with respect to the standard products are known. However, there is, until now, no known algorithm to compute the PFD of directed graphs with respect to the direct and the strong product in general. In this contribution, we focus on the algorithmic aspects for determining the PFD of directed graphs with respect to the strong product. Essential for computing the prime factors is the construction of a so-called Cartesian skeleton. This article introduces the notion of the Cartesian skeleton of directed graphs as a generalization of the Cartesian skeleton of undirected graphs. We provide new, fast and transparent algorithms for its construction. It leads to the first polynomial-time algorithm for determining the PFD of arbitrary, finite connected digraphs with respect to the strong product. [ABSTRACT FROM AUTHOR]

The genetic diversity in durum wheat, Triticum turgidum durum, has been strongly reduced since the domestication of the wild Triticum turgidum dicoccoides. Monitoring durum wheat composite crosses incorporating related tetraploid taxa, such as wild and domesticated emmer wheat, is a suitable evolutionary pre-breeding method. Transcriptome sequencing paves the way for a genomic survey of single nucleotide polymorphisms (SNPs) segregating in such populations, offering the possibility of genotyping by sequencing to use these resources in genome-wide association studies (GWAS) and genomic selection (GS) programs. Evolutionary Pre-breeding pOpulation (EPO) is an evolutionary durum wheat pre-breeding population. Sequencing the transcriptome of 179 durum wheat lines (175 from EPO) led to the detection of 103,262 SNPs on two reference transcriptomes: one from the International Wheat Genome Sequencing Consortium and one assembled de novo on durum wheat. Using strict filtering to remove dubious heterozygous SNPs, EPO genetic diversity was eventually described with 76,188 high-confidence SNPs. The percentage of missing genotyping data depended on the expression level, and 88 individuals out of 175 were genotyped per SNP on average. Using the 3B pseudo-molecule of bread wheat, the transcription and diversity levels were shown to be higher in distal regions than in proximal regions, but SNPs were available throughout the chromosomes. Assuming good synteny with Hordeum, the trend was similar on the 14 chromosomes of the durum wheat genome. EPO hosts a high level of diversity, has a number of SNPs in low linkage disequilibrium (<40 Mb) and would be well suited for GWAS and GS programs. [ABSTRACT FROM AUTHOR]