Much work has been done on the subject of what happens to software architecture during maintenance activities. There seems to be a consensus that it degrades during the evolution of the software. More recent work shows that this degradation occurs even during development activities: design decisions are either adjusted or forgotten. Some studies have looked into the causes of this degradation, but these have mostly done so at a very high level. This study examines three projects at code level. Three architectural pre-implementation designs are compared with their post-implementation design counterparts, with special attention paid to the causes of the changes. We found many negative changes causing anti-patterns, at the package, class, and method levels. After analysis of the code, we were able to find the specific reasons for the poor design decisions. Although the underlying causes are varied, they can be grouped into three basic categories: knowledge problems, artifact problems, and management problems. This categorization shows that anti-pattern causes are varied and are not all due to the developers. The main conclusion is that promoting awareness of anti-patterns to developers is insufficient to prevent them since some of the causes escape their grasp.
Feruloyl esterases (FAEs) and acetyl xylan esterases (AXEs) are important enzymes for plant biomass degradation and are both present in Carbohydrate Esterase family 1 (CE1) of the Carbohydrate‐Active enZymes database. In this study, ten novel fungal CE1 enzymes from different subfamilies were heterologously produced and screened for their activity towards model and complex plant biomass substrates. CE1_1 enzymes possess AXE activity, while CE1_5 enzymes showed FAE activity. Two enzymes from CE1_2 and one from CE1_5 possess dual feruloyl/acetyl xylan esterase (FXE) activity, showing expansion of substrate specificity. The new FXEs from CE1 can efficiently release both feruloyl and acetyl residues from feruloylated xylan, making them particularly interesting novel components of industrial enzyme cocktails for plant biomass degradation.
Software process model rarely takes into account knowledge required to build software. This paper presents a new approach to software process modeling, which enables the mapping of knowledge required by the activity roles and stored into the activity input artifacts. Comparing knowledge concepts required for the various activities provides information on the knowledge gaps between the models elements involved. This information is fed into a dashboard, which outlines any knowledge discrepancies within the software process model and enables process manager to mitigate risks associated to knowledge within a given task.
Background Feruloyl esterases (FAEs) and acetyl xylan esterases (AXEs) are important accessory enzymes in the deconstruction of plant biomass. Carbohydrate Esterase family 1 (CE1) of the Carbohydrate-Active enZymes database contains both fungal FAEs and AXEs, sharing a high amino acid sequence similarity, even though they target different structural molecules on plant cell wall polysaccharides. Results We recently classified fungal CE1 into five subfamilies (CE1_SF1-5). In this study, ten novel fungal CE1 enzymes from different subfamilies were heterologously produced in Aspergillus niger and characterized to gain insight on relationships among these esterases. The enzymes from CE1_SF1 possess AXE activity, as they hydrolyzed p NP-acetate and released acetic acid from wheat arabinoxylan, but were not active towards FAE substrates. CE1_SF5 showed FAE activity as they hydrolyzed methyl ferulate and other FAE related substrates, and release ferulic acid from wheat arabinoxylan. These FAEs preferred feruloylated arabinoxylan over pectin. Two CE1_SF2, sharing over 70% amino acid sequence identity, possessed the opposite activity. Interestingly, one enzyme from CE1_SF1 and one from CE1_SF5 possess dual feruloyl/acetyl xylan esterase (FXE) activity. These dual activity enzymes showed expansion of substrate specificity. Conclusions The new FXEs from CE1 can efficiently release both ferulic acid and acetic acid from feruloylated xylan, making them particularly interesting novel components of industrial enzyme cocktails for plant biomass degradation.
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