Type-changing rewriting and semantics-preserving transformation

We have identified a class of whole-program transformations that are regular in structure and require changing the types of terms throughout a program while simultaneously preserving the initial semantics after transformation. This class of transformations cannot be safely performed with typical term rewriting techniques, which do not allow for changing the types of terms. In this paper, we present a formalization of type-and-transform systems, an automated approach to the whole-program transformation of terms of one type to terms of a different, isomorphic type using type-changing rewrite rules. A type-and-transform system defines typing and semantics relations between all corresponding source and target subprograms such that a complete transformation guarantees that the whole programs have equivalent types and semantics. We describe the type-and-transform system for the lambda calculus with let-polymorphism and general recursion, including several examples from the literature and properties of the system. (C) 2015 Elsevier B.V. All rights reserved

Type-changing rewriting and semantics-preserving transformation

We have identified a class of whole-program transformations that are regular in structure and require changing the types of terms throughout a program while simultaneously preserving the initial semantics after transformation. This class of transformations cannot be safely performed with typical term rewriting techniques, which do not allow for changing the types of terms. In this paper, we present a formalization of type-and-transform systems, an automated approach to the whole-program transformation of terms of one type to terms of a different, isomorphic type using type-changing rewrite rules. A type-and-transform system defines typing and semantics relations between all corresponding source and target subprograms such that a complete transformation guarantees that the whole programs have equivalent types and semantics. We describe the type-and-transform system for the lambda calculus with let-polymorphism and general recursion, including several examples from the literature and properties of the system

Type-Changing Rewriting and Semantics-Preserving Transformation

We have identified a class of whole-program transformations that are regular in structure and require changing the types of terms throughout a program while simultaneously preserving the initial semantics after transformation. This class of transformations cannot be safely performed with typical term rewriting techniques, which do not allow for changing the types of terms. In this paper, we present a formalization of type-and-transform systems, an automated approach to the whole-program transformation of terms of one type to terms of a different, isomorphic type using type-changing rewrite rules. A type-and-transform system defines typing and semantics relations between all corresponding source and target subprograms such that a complete transformation guarantees that the whole programs have equivalent types and semantics. We describe the type-and-transform system for the lambda calculus with let-polymorphism and general recursion, including several examples from the literature and properties of the system

The gold-standard genome of Aspergillus niger NRRL 3 enables a detailed view of the diversity of sugar catabolism in fungi

The fungal kingdom is too large to be discovered exclusively by classical genetics. The access to omics data opens a new opportunity to study the diversity within the fungal kingdom and how adaptation to new environments shapes fungal metabolism. Genomes are the foundation of modern science but their quality is crucial when analysing omics data. In this study, we demonstrate how one gold-standard genome can improve functional prediction across closely related species to be able to identify key enzymes, reactions and pathways with the focus on primary carbon metabolism. Based on this approach we identified alternative genes encoding various steps of the different sugar catabolic pathways, and as such provided leads for functional studies into this topic. We also revealed significant diversity with respect to genome content, although this did not always correlate to the ability of the species to use the corresponding sugar as a carbon source

Consequences of negative energy balance on follicular development and oocyte quality in primiparous sows

Metabolic demands of modern hybrid sows have increased over the years, which increases the chance that sows enter a substantial negative energy balance (NEB) during lactation. This NEB can influence the development of follicles and oocytes that will give rise to the next litter. To study effects of a lactational NEB on follicular development, we used 36 primiparous sows of which 18 were subjected to feed restriction (3.25 kg/day) and 18 were full-fed (6.5 kg/day) during the last two weeks of a 24.1 ± 0.3 day lactation. Feed restriction resulted in a 70% larger lactational body weight loss and 76% higher longissimus dorsi depth loss, but similar amounts of backfat loss compared to the full fed sows. These changes were accompanied by lower plasma insulin-like growth factor 1 (IGF1) and higher plasma creatinine levels in the restricted sows from the last week of lactation onwards. Ovaries were collected 48 h after weaning. Restricted sows had a lower average size of the 15 largest follicles (−26%) and cumulus-oocyte complexes showed less expansion after 22 h in vitro maturation (−26%). Less zygotes of restricted sows reached the metaphase stage 24 h after in vitro fertilization and showed a higher incidence of polyspermy (+89%). This shows that feed restriction had severe consequences on oocyte developmental competence. Follicular fluid of restricted sows had lower IGF1 (−56%) and steroids levels (e.g. β-estradiol, progestins and androgens), which indicated that follicles of restricted sows were less competent to produce steroids and growth factors needed for oocytes to obtain full developmental competence