28,470 research outputs found

    <i>AKARI</i>/IRC source catalogues and source counts for the IRAC Dark Field, ELAIS North and the <i>AKARI</i> Deep Field South

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    We present the first detailed analysis of three extragalactic fields (IRAC Dark Field, ELAIS-N1, ADF-S) observed by the infrared satellite, AKARI, using an optimized data analysis toolkit specifically for the processing of extragalactic point sources. The InfaRed Camera (IRC) on AKARI complements the SpitzerSpace Telescope via its comprehensive coverage between 8–24 μm filling the gap between the Spitzer/IRAC and MIPS instruments. Source counts in the AKARI bands at 3.2, 4.1, 7, 11, 15 and 18 μm are presented. At near-infrared wavelengths, our source counts are consistent with counts made in other AKARI fields and in general with SpitzerIRAC (except at 3.2 μm where our counts lie above). In the mid-infrared (11 – 18 μm), we find our counts are consistent with both previous surveys by AKARI and the Spitzer peak-up imaging survey with the InfraRed Spectrograph (IRS). Using our counts to constrain contemporary evolutionary models, we find that although the models and counts are in agreement at mid-infrared wavelengths there are inconsistencies at wavelengths shortward of 7 μm, suggesting either a problem with stellar subtraction or indicating the need for refinement of the stellar population models. We have also investigated the AKARI/IRC filters, and find an active galactic nucleus selection criteria out to z AKARI 4.1, 11, 15 and 18 μm colours

    Worked shell from the Northern Moluccas

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    The Northern Moluccas occupy a pivotal geographical zone at the interface of the Island Southeast Asian and Melanesian spheres. Whether one looks at genes, languages, Holocene animal translocations, or the archaeological record, it is clear that the cultures through time on these islands have both been shaped by, and have contributed to shaping, the complex fusion of influences that characterises the Asia/Pacific margin. The project reported on in this monograph intensively investigated this area for the first time, and uncovered a rich range of sites spanning c. 35,000 years of the islands’ history. There are few constants in the archaeological record that can be tracked through time. The vertebrate record of the Northern Moluccas shows dramatic shifts at different points in the past, and the ceramic record is necessarily restricted to the last few thousand years. The pre‑eminence of lithic technology in the study of human cultural change through time is due to its global presence as a robust archaeological constant, but in Island Southeast Asia, and the Northern Moluccas in particular, another constant has emerged: shell technology. From the earliest archaeological deposits at the oldest excavated site, Golo Cave, a range of shell technologies were in use ranging from the formal to the expedient (Szabó et al. 2007; Szabó and Koppel 2015). In contrast, associated lithic technologies were found to be non-standardised and uncomplicated in their manufacture (Szabó et al. 2007). While, to some extent, the early diversification of shell technologies at Golo Cave can be seen as a response to the low-quality lithic materials that were locally available, this in itself does not provide an adequate explanation. The diversity of shell-working from the lowest levels at Golo, both in terms of materials used and reduction techniques employed, clearly implies that a broad tradition of shell-working was well established by the time the site was initially occupied. Additionally, the techniques applied to various types of shell diverge from those applied to lithic material, confirming that shell was no simple technological substitute for stone. The range of stratified sites excavated as part of this archaeological project provides snapshots through time of the rise and decline of a variety of shell-working traditions. Some have clear links beyond the Northern Moluccas whilst others are seemingly idiosyncratic. The shell artefacts will be reported upon site by site, with temporal patterning and extra-Moluccan associations being considered in the discussion section

    Relating Developers’ Concepts and Artefact Vocabulary in a Financial Software Module

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    Developers working on unfamiliar systems are challenged to accurately identify where and how high-level concepts are implemented in the source code. Without additional help, concept location can become a tedious, time-consuming and error-prone task. In this paper we study an industrial financial application for which we had access to the user guide, the source code, and some change requests. We compared the relative importance of the domain concepts, as understood by developers, in the user manual and in the source code. We also searched the code for the concepts occurring in change requests, to see if they could point developers to code to be modified. We varied the searches (using exact and stem matching, discarding stop-words, etc.) and present the precision and recall. We discuss the implication of our results for maintenance

    Multi-elemental speciation analysis of barley genotypes diering in tolerance to cadmium toxicity using SEC-ICP-MS and ESI-TOF-MS

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    Plants respond to Cd exposure by synthesizing heavy-metal-binding oligopeptides, called phytochelatins (PCs). These peptides reduce the activity of Cd2+ ions in the plant tissues by forming Cd chelates. The main objective of the present work was to develop an analytical technique, which allowed identication of the most prominent Cd species in plant tissue by SEC-ICP-MS and ESI-TOF-MS. An integrated part of the method development was to test the hypothesis that dierential Cd tolerance between two barley genotypes was linked to dierences in Cd speciation. Only one fraction of Cd species, ranging from 7001800 Da, was detected in the shoots of both genotypes. In the roots, two additional fractions ranging from 29004600 and 670015 000 Da were found. The Cd-rich SEC fractions were heart-cut, de-salted and demetallized using reversed-phase chromatography (RPC), followed by ESI-MS-TOF to identify the ligands. Three dierent families of PCs, viz. (gGlu-Cys)n-Gly (PCn), (gGlu-Cys)n-Ser (iso-PCn) and Cys-(gGlu-Cys)n-Gly (des-gGlu-PCn), the last lacking the N-terminal amino acid, were identied. The PCs induced by Cd toxicity also bound several essential trace elements in plants, including Zn, Cu, and Ni, whereas no Mn species were detected. Zn, Cu and Ni-species were distributed between the 7001800 Da and 670015 000 Da fractions, whereas only Cd species were found in the 29004600 Da fraction dominated by PC3 ligands. Although the total tissue concentration of Cd was similar for the two species, the tolerant barley genotype synthesized signicantly more CdPC3 species with a high Cd specicity than the intolerant genotype, clearly indicating a correlation between Cd tolerance and the CdPC speciation

    Areal surface texture data extraction from x-ray computed tomography reconstructions of metal additively manufactured parts

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    Many applications that exploit the manufacturing flexibility of additive manufacturing (AM) produce surfaces, primarily internal features, which cannot be measured using conventional contact or line-of-sight optical methods. This paper evaluates the capability of a novel technique to extract areal surface data from micro-focus x-ray computed tomography (XCT) from AM components and then generate surface parameter data per ISO 25178-2. This non-destructive evaluation of internal features has potential advantages during AM product research and commercial production. The data extracted from XCT is compared with data extracted using a focus variation instrument. A reference dimensional artefact is included in all XCT measurements to evaluate XCT surface determination performance and dimensional scaling accuracy. Selected areal parameters generated using the extraction technique are compared, including Sa, for which the nominal difference between the value obtained using XCT and used the focus variation method was less than 2.5%
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