Improved ontology for eukaryotic single-exon coding sequences in biological databases

Indexación: Scopus.Efficient extraction of knowledge from biological data requires the development of structured vocabularies to unambiguously define biological terms. This paper proposes descriptions and definitions to disambiguate the term 'single-exon gene'. Eukaryotic Single-Exon Genes (SEGs) have been defined as genes that do not have introns in their protein coding sequences. They have been studied not only to determine their origin and evolution but also because their expression has been linked to several types of human cancer and neurological/developmental disorders and many exhibit tissue-specific transcription. Unfortunately, the term 'SEGs' is rife with ambiguity, leading to biological misinterpretations. In the classic definition, no distinction is made between SEGs that harbor introns in their untranslated regions (UTRs) versus those without. This distinction is important to make because the presence of introns in UTRs affects transcriptional regulation and post-transcriptional processing of the mRNA. In addition, recent whole-transcriptome shotgun sequencing has led to the discovery of many examples of single-exon mRNAs that arise from alternative splicing of multi-exon genes, these single-exon isoforms are being confused with SEGs despite their clearly different origin. The increasing expansion of RNA-seq datasets makes it imperative to distinguish the different SEG types before annotation errors become indelibly propagated in biological databases. This paper develops a structured vocabulary for their disambiguation, allowing a major reassessment of their evolutionary trajectories, regulation, RNA processing and transport, and provides the opportunity to improve the detection of gene associations with disorders including cancers, neurological and developmental diseases. © The Author(s) 2018. Published by Oxford University Press.https://academic.oup.com/database/article/doi/10.1093/database/bay089/509943

Mechanization of and experience with a triplex fly-by-wire backup control system

A redundant three axis analog control system was designed and developed to back up a digital fly by wire control system for an F-8C airplane. The mechanization and operational experience with the backup control system, the problems involved in synchronizing it with the primary system, and the reliability of the system are discussed. The backup control system was dissimilar to the primary system, and it provided satisfactory handling through the flight envelope evaluated. Limited flight tests of a variety of control tasks showed that control was also satisfactory when the backup control system was controlled by a minimum displacement (force) side stick. The operational reliability of the F-8 digital fly by wire control system was satisfactory, with no unintentional downmodes to the backup control system in flight. The ground and flight reliability of the system's components is discussed

Mechanization of and experience with a triplex fly-by-wire backup control system

A redundant three-axis analog control system was designed and developed to back up a digital fly-by-wire control system for an F-8C airplane. Forty-two flights, involving 58 hours of flight time, were flown by six pilots. The mechanization and operational experience with the backup control system, the problems involved in synchronizing it with the primary system, and the reliability of the system are discussed. The backup control system was dissimilar to the primary system, and it provided satisfactory handling through the flight envelope evaluated. Limited flight tests of a variety of control tasks showed that control was also satisfactory when the backup control system was controlled by a minimum-displacement (force) side stick. The operational reliability of the F-8 digital fly-by-wire control system was satisfactory, with no unintentional downmodes to the backup control system in flight. The ground and flight reliability of the system's components is discussed

Copy number variation and genomic alterations in health and disease

A report of the 1st GOLDEN HELIX Symposium 'Copy number variation and genomic alterations in health and disease', Athens, Greece, 28-29 November 2008

Investigating green supply chain management practices and performance: the moderating roles of supply chain ecocentricity and traceability

Sustainable supply chain management has become an increasingly important driver of business performance. Understanding the contingent nature of how performance is improved in this context is therefore a critical task for management. We explore the moderating effects of two practices unique to sustainable supply chain - ecocentricity and supply chain traceability - on a firm’s environmental and operating cost performance. Design: Survey data were collected from 248 UK manufacturing firms and analyzed using moderated hierarchical regression. Findings: The results suggest that green supply chain management practices are associated with improvements in both environmental and cost-based performance. Further, higher levels of ecocentricity and supply chain traceability are associated with stronger relationships between green supply chain management practices and cost performance. Contrary to expectations, high levels of supply chain traceability were found to negatively moderate the relationship between green supply chain management practices and environmental performance. Limitations: Our research design was survey-based and cross-sectional. Future studies would benefit from longitudinal research designs that capture the effects of GSCM practices on performance over an extended period. Our survey data is also perceptual; using secondary data to capture environmental performance outcomes, for example, would be another opportunity for future research. Practical Implications: We provide additional support to findings that green supply chain management practices benefit both environmental and cost performance dimensions. In this context, we show that investments by firms in working with a broader set of eco-system partners (ecocentricity) and building supply chain traceability and leads to improved environmental sustainability outcomes. We encourage managers to carefully consider how they conceptualize and monitor their supply chains. Not applicable. Originality: This paper offers several contributions to the research in this area. First, we develop and validate a measurement scale for ecocentricity and supply chain traceability. Second, we show how these two variables – unique to sustainable supply chains – can positively influence firm and environmental performance

Isoperimetric Inequalities for Minimal Submanifolds in Riemannian Manifolds: A Counterexample in Higher Codimension

For compact Riemannian manifolds with convex boundary, B.White proved the following alternative: Either there is an isoperimetric inequality for minimal hypersurfaces or there exists a closed minimal hypersurface, possibly with a small singular set. There is the natural question if a similar result is true for submanifolds of higher codimension. Specifically, B.White asked if the non-existence of an isoperimetric inequality for k-varifolds implies the existence of a nonzero, stationary, integral k-varifold. We present examples showing that this is not true in codimension greater than two. The key step is the construction of a Riemannian metric on the closed four-dimensional ball B with the following properties: (1) B has strictly convex boundary. (2) There exists a complete nonconstant geodesic. (3) There does not exist a closed geodesic in B.Comment: 11 pages, We changed the title and added a section that exhibits the relation between our example and the question posed by Brian White concerning isoperimetric inequalities for minimal submanifold

Bounded Counter Languages

We show that deterministic finite automata equipped with $k$ two-way heads are equivalent to deterministic machines with a single two-way input head and $k-1$ linearly bounded counters if the accepted language is strictly bounded, i.e., a subset of $a_1^*a_2^*... a_m^*$ for a fixed sequence of symbols $a_1, a_2,..., a_m$. Then we investigate linear speed-up for counter machines. Lower and upper time bounds for concrete recognition problems are shown, implying that in general linear speed-up does not hold for counter machines. For bounded languages we develop a technique for speeding up computations by any constant factor at the expense of adding a fixed number of counters