437 research outputs found
Cyber-physical systems design for runtime trustworthiness maintenance supported by tools
The trustworthiness of cyber-physical systems is a critical factor for establishing wide-spread adoption of these systems. Hence, especially the behavior of safety-critical software components needs to be monitored and managed during system operation. Runtime trustworthiness maintenance should be planned and prepared in early requirements and design phases. This involves the identification of threats that may occur and affect user’s trust at runtime, as well as related controls that can be executed to mitigate the threats. Furthermore, observable and measureable system quality properties have to be identified as indicators of threats, and interfaces for reporting these properties as well as for executing controls have to be designed and implemented. This paper presents a process model for preparing and designing systems for runtime trustworthiness maintenance, which is supported by several tools that facilitate the tasks to be performed by requirements engineers and system designer
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G-TRACE: rapid Gal4-based cell lineage analysis in Drosophila.
We combined Gal4-UAS and the FLP recombinase-FRT and fluorescent reporters to generate cell clones that provide spatial, temporal and genetic information about the origins of individual cells in Drosophila melanogaster. We named this combination the Gal4 technique for real-time and clonal expression (G-TRACE). The approach should allow for screening and the identification of real-time and lineage-traced expression patterns on a genomic scale
The digestive system of xenacoelomorphs
Interest in the study of Xenacoelomorpha has recently been revived due to realization of its key phylogenetic position as the putative sister group of the remaining Bilateria. Phylogenomic studies have attracted the attention of researchers interested in the evolution of animals and the origin of novelties. However, it is clear that a proper understanding of novelties can only be gained in the context of thorough descriptions of the anatomy of the different members of this phylum. A considerable literature, based mainly on conventional histological techniques, describes different aspects of xenacoelomorphs’ tissue architecture. However, the focus has been somewhat uneven; some tissues, such as the neuro-muscular system, are relatively well described in most groups, whereas others, including the digestive system, are only poorly understood. Our lack of knowledge of the xenacoelomorph digestive system is exacerbated by the assumption that, at least in Acoela, which possess a syncytial gut, the digestive system is a derived and specialized tissue with little bearing on what is observed in other bilaterian animals. Here, we try to remedy this lack of attention by revisiting the different studies of the xenacoelomorph digestive system, and we discuss the diversity present in the light of new evolutionary knowledge
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Demonstration of a VOC in-situ fiber optic sensor for use with a penetrometer analysis system
Researchers at the Idaho National Engineering Laboratory with their industrial CRADA partner GEOCENTERS demonstrated a fiber optic based VOC sensor at the Army Environmental Center (AEC) technology demonstration at Dover Air Force Base. The sensor used during the demonstration was a single fiber optic cable coupled to an in situ sensor element contained in a cone penetrometer tip. The sensor`s fluorescence response was measured at the surface using an optical breadboard-based instrument. Results from this demonstration showed that the sensor provided semi-quantitative results for total VOCs comparable to the historical values of VOCs. In addition, the demonstration identified several technical challenges for improvement of the sensor. This paper describes the analytical properties of the reversible sensing materials, construction of an improved sensor system, and the planned demonstration of the modified in-situ VOC sensor system. This sensor system is tentatively scheduled for demonstration at the Army Environmental Center`s Aberdeen Proving Ground Test site. Improvements to the VOC sensor system include an optical configuration that will correct for soil matrix interferences and multiple sensing substrates to learn whether VOC selectivity can be achieved
An Integrated Micro- and Macroarchitectural Analysis of the Drosophila Brain by Computer-Assisted Serial Section Electron Microscopy
A new software package allows for dense electron microscopy reconstructions of neuronal networks in the fruit fly brain, and reveals specific differences in microcircuits between insects and vertebrates
Specification of Drosophila Corpora Cardiaca Neuroendocrine Cells from Mesoderm Is Regulated by Notch Signaling
Drosophila neuroendocrine cells comprising the corpora cardiaca (CC) are essential for systemic glucose regulation and represent functional orthologues of vertebrate pancreatic α-cells. Although Drosophila CC cells have been regarded as developmental orthologues of pituitary gland, the genetic regulation of CC development is poorly understood. From a genetic screen, we identified multiple novel regulators of CC development, including Notch signaling factors. Our studies demonstrate that the disruption of Notch signaling can lead to the expansion of CC cells. Live imaging demonstrates localized emergence of extra precursor cells as the basis of CC expansion in Notch mutants. Contrary to a recent report, we unexpectedly found that CC cells originate from head mesoderm. We show that Tinman expression in head mesoderm is regulated by Notch signaling and that the combination of Daughterless and Tinman is sufficient for ectopic CC specification in mesoderm. Understanding the cellular, genetic, signaling, and transcriptional basis of CC cell specification and expansion should accelerate discovery of molecular mechanisms regulating ontogeny of organs that control metabolism
A genome-wide resource for the analysis of protein localisation in Drosophila
The Drosophila genome contains >13000 protein-coding genes, the majority of which remain poorly investigated. Important reasons include the lack of antibodies or reporter constructs to visualise these proteins. Here, we present a genome-wide fosmid library of 10000 GFP-tagged clones, comprising tagged genes and most of their regulatory information. For 880 tagged proteins, we created transgenic lines, and for a total of 207 lines, we assessed protein expression and localisation in ovaries, embryos, pupae or adults by stainings and live imaging approaches. Importantly, we visualised many proteins at endogenous expression levels and found a large fraction of them localising to subcellular compartments. By applying genetic complementation tests, we estimate that about two-thirds of the tagged proteins are functional. Moreover, these tagged proteins enable interaction proteomics from developing pupae and adult flies. Taken together, this resource will boost systematic analysis of protein expression and localisation in various cellular and developmental contexts
Dynamics of Endoreplication during Drosophila Posterior Scutellar Macrochaete Development
Endoreplication is a variant type of DNA replication, consisting only of alternating G1 and S phases. Many types of Drosophila tissues undergo endoreplication. However, the timing and the extent to which a single endocycling macrochaete undergoes temporally programmed endoreplication during development are unclear. Here, we focused on the dynamics of endoreplication during posterior scutellar (pSC) macrochaete development. Quantitative analyses of C values in shaft cells and socket cells revealed a gradual rise from 8C and 4C at 8 hours after pupal formation (APF) to 72C and 24C at 29 hours APF, respectively. The validity of the values was further confirmed by the measurement of DNA content with a confocal laser microscope. BrdU incorporation assays demonstrated that shaft cells undergo four rounds of endoreplication from 18 to 29.5 hours APF. In contrast, socket cells undergo two rounds of endoreplication during the same period. Statistical analyses showed that the theoretical C values, based on BrdU assays, nearly coincide with the actually measured C values in socket cells, but not in shaft cells after 22 hours APF. These analyses suggest that socket cells undergo two rounds of endoreplication. However, the mechanism of endoreplication in the shaft cells may change from 22 hours APF, suggesting the possibility that shaft cells undergo two or four rounds of endoreplication during the periods. We also found that the timing of endoreplication differs, depending on the type of macrochaete. Moreover, endocycling in shaft cells of both the left and right sides of pSC bristle lineages occurs in the same pattern, indicating that the process is synchronized for specific types of macrochaete. Our findings suggest that endocycling in macrochaete cell lineages can be a model for understanding mechanisms of endoreplication at the single-cell level
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