New iron-based Heusler compounds Fe2YZ: Comparison with theoretical predictions of the crystal structure and magnetic properties

The present work reports on the new soft ferromagnetic Heusler phases Fe2NiGe, Fe2CuGa, and Fe2CuAl, which in previous theoretical studies have been predicted to exist in a tetragonal regular Heusler structure. Together with the known phases Fe2CoGe and Fe2NiGa these materials have been synthesized and characterized by powder XRD, 57 Fe M\"ossbauer spectroscopy, SQUID and EDX measurements. In particular M\"ossbauer spectroscopy was used to monitor the degree of local atomic order/disorder and to estimate magnetic moments at the Fe sites from the hyperfine fields. It is shown that in contrast to the previous predictions all the materials except Fe2NiGa basically adopt the inverse cubic Heusler (X-) structure with differing degrees of disorder. The disorder is more enhanced in case of Fe2NiGa, which was predicted as an inverse Heusler phase. The experimental data are compared with results from ab-inito electronic structure calculations on LDA level incorporating the effects of atomic disorder by using the coherent potential approximation (CPA). A good agreement between calculated and experimental magnetic moments is found for the cubic inverse Heusler phases. Model calculations on various atomic configurations demonstrate that antisite disorder tends to enhance the stability of the X-structure. Given the fundamental scientific and technological importance of tetragonal Heusler phases the present results call for further investigations to unravel the factors stabilizing tetragonal Heusler materials

Predictors of Individual-Level Innovation at Work: A Meta-Analysis

peer-reviewedNumerous narrative reviews related to innovation in work organizations have been published, yet very few quantitative reviews have been conducted. The present meta-analysis investigates the relationships between four predictor types (individual differences, motivation, job characteristics, and contextual influences) and individual-level workplace innovation. Results indicated that individual factors, characteristics of the job, and factors of the environment were moderately associated with phases of the innovation process. Implications for future research opportunities are discussed.ACCEPTEDpeer-reviewe

Separate effects tests on hydrogen combustion during direct containment heating events

Experimente zur Wasserstoffverbrennung bei DCH-Prozessen Im Rahmen der Forschung zu schweren Unfällen in Leichtwasserreaktoren werden im Institut für Energie- und Kerntechnik des Forschungszentrums Karlsruhe seit 1998 die Versuchanlagen DISCOC und DISCO-H betrieben, konzipiert zur Untersuchung der Druckbelastung des Sicherheitsbehälters durch Schmelzedispersion (Direct Containment Heating, DCH) bei Versagen des Reaktordruckbehälters (RDB). Vorangegangene Experimente haben die Schmelzeverteilung und Druckerhöhung im Sicherheitsbehälter bei verschiedenen europäischen Reaktorgeometrien untersucht, unter Anwendung von Eisen-Aluminium-Schmelzen und Dampf als Modellfluide. Die Analyse dieser Experimente hat gezeigt, dass der Druckanstieg sowohl durch den Wärmeübergang von der Schmelze an das Gas, aber auch zum nicht unerheblichen Teil durch Wasserstoffverbrennung verursacht wurde. So hat sich die Notwendigkeit ergeben, die charakteristischen Eigenschaften der Wasserstoffverbrennung während des DCH-Prozesses besser beschreiben zu können. Um diese Fragen zu klären, wurden Einzeleffektexperimente in der DISCO-H Versuchsanlage durchgeführt. Mit Ausnahme der Schmelzedispersion laufen in diesen Experimenten die gleichen Prozesse ab, wie sie während des DCH-Vorganges auftreten, das sind das Abblasen einer heißen Wasserstoff-Dampf Mischung in den Sicherheitsbehälter und die Zündung dieses Gasgemisches in einer LuftDampf-Wasserstoff Atmosphäre. Der Effekt der Schmelzepartikel als Zünder wurde mit Thermitkerzen simuliert. Die experimentellen Daten werden benutzt, um Modelle in Verbrennungscodes zu kalibrieren und um auf Reaktormaßstab zu extrapolieren. Die Experimente wurden in zwei Schritten durchgeführt. Für eine Serie von 6 Tests wurde eine vereinfachte Geometrie benutzt, um die Hauptparameter der Verbrennung zu studieren. Dann wurden zwei Tests in einer prototypischeren Geometrie durchgeführt, bei der das Gas aus der Grube zuerst in einen separaten Reaktorraum und von dort in den Sicherheitsbehälter strömt. Die Versuchsbedingungen waren wie folgt: • Als Anfangsbedingung im Sicherheitsbehälter wurde eine Luft- bzw. ein Luft-Dampf-Atmosphäre bei 100°C und 2 bar eingestellt, mit Wasserstoffkonzentrationen zwischen 0 und 7 mol%, repräsentativ für die Atmosphäre im Containment bei Versagen des RDB. • Einblasen eines heißen Dampf-Wasserstoffgemisches in die Reaktorgrube bei 20 bar, repräsentativ für ein Kühlmittelabblasen durch ein Leck im RDB und der Wasserstofferzeugung während dieser Phase. Die wichtigsten gemessenen Größen waren (1) der Druckanstieg im Sicherheitsbehälter, (2) die Gastemperaturen und (3) die Anzahl der verbrannten Wasserstoffmole. Diese Experimente kennzeichnen die Rate der Wasserstoffverbrennung, die Vollständigkeit und die Art der Verbrennung bei verschiedenen Anfangsbedingungen. Der Anteil des verbrannten Wasserstoffs betrug zwischen 55% und 100% der Gesamtmenge in der einfachen Geometrie und 46% bzw. 67% in der mehr prototypischen Geometrie. Der Wirkungsgrad hinsichtlich Druckerhöhung im Sicherheitsbehälter lag zwischen 46% und 67%. Spezielle Verbrennungscodes müssen angewendet werden um zu prüfen, ob diese Ergebnisse auch für den Reaktormaßstab gelten

From near and far: Stone procurement and exchange at Çukuriçi Höyük in Western Anatolia

The focus of this paper are the stone tools of Çukuriçi Höyük, a prehistoric site situated at the central Aegean coast of Anatolia. The settlement was inhabited from the Neolithic, through the Late Chalcolithic and Early Bronze Age 1 periods, a period lasting from the early 7th to the early 3rd millennium BCE. A long-term interdisciplinary study of the excavated lithics with different scientific methods on various stone materials (thin section analysis, pXRF, NAA, LA-ICP-MS) offer new primary data about the procurement strategies of prehistoric societies from a diachronic perspective. The results will be presented for the first time with an overview of all source materials and their distinct use through time. The lithic assemblages from Çukuriçi Höyük consist of a considerable variety of small finds, grinding stones and chipped stone tools. The high variability of raw materials within the different categories of tools is remarkable. In addition to stone tools manufactured from sources in the immediate vicinity of the settlement (i.e., mica-schist, limestone, marble, amphibolite, serpentinite), others are of rock types such as chert, which indicate an origin within the broader region. Moreover, volcanic rocks, notably the exceptionally high amount of Melian obsidian found at Çukuriçi Höyük, attest to the supra-regional procurement of distinct rock types. Small stone axes made of jadeite presumably from the Greek island of Syros, also indicate these far-reaching procurement strategies. The systematic and diachronic analyses of the stone tools found at Çukuriçi Höyük has demonstrated that as early as the Neolithic period extensive efforts were made to supply the settlement with carefully selected raw materials or finished goods procured from distinct rock sources.   Erratum:• This article was submitted and initially published with only the following authors listed: Christoph Schwall, Michael Brandl, Tatjana M. Gluhak, Bogdana Milić, Lisa Betina, Lasse Sørensen, Danilo Wolf, and Barbara Horejs. After publication of the article, the authors observed that they had forgotten to include Maria M. Martinez as an author and requested that she be added to the list of authors. The current version of the article includes Maria M. Martinez. She should be considered an author also for earlier versions of the article that might be in circulation. &nbsp

Tunable phenotypic variability through an autoregulatory alternative sigma factor circuit.

Genetically identical individuals in bacterial populations can display significant phenotypic variability. This variability can be functional, for example by allowing a fraction of stress prepared cells to survive an otherwise lethal stress. The optimal fraction of stress prepared cells depends on environmental conditions. However, how bacterial populations modulate their level of phenotypic variability remains unclear. Here we show that the alternative sigma factor σV circuit in Bacillus subtilis generates functional phenotypic variability that can be tuned by stress level, environmental history and genetic perturbations. Using single-cell time-lapse microscopy and microfluidics, we find the fraction of cells that immediately activate σV under lysozyme stress depends on stress level and on a transcriptional memory of previous stress. Iteration between model and experiment reveals that this tunability can be explained by the autoregulatory feedback structure of the sigV operon. As predicted by the model, genetic perturbations to the operon also modulate the response variability. The conserved sigma-anti-sigma autoregulation motif is thus a simple mechanism for bacterial populations to modulate their heterogeneity based on their environment

Control of starch branching in barley defined through differential RNAi suppression of starch branching enzyme IIa and IIb

The roles of starch branching enzyme (SBE, EC 2.4.1.18) IIa and SBE IIb in defining the structure of amylose and amylopectin in barley (Hordeum vulgare) endosperm were examined. Barley lines with low expression of SBE IIa or SBE IIb, and with the low expression of both isoforms were generated through RNA-mediated silencing technology. These lines enabled the study of the role of each of these isoforms in determining the amylose content, the distribution of chain lengths, and the frequency of branching in both amylose and amylopectin. In lines where both SBE IIa and SBE IIb expression were reduced by >80%, a high amylose phenotype (>70%) was observed, while a reduction in the expression of either of these isoforms alone had minor impact on amylose content. The structure and properties of the high amylose starch resulting from the concomitant reduction in the expression of both isoforms of SBE II in barley were found to approximate changes seen in amylose extender mutants of maize, which result from lesions eliminating expression of the SBE IIb gene. Amylopectin chain length distribution analysis indicated that both SBE IIa and SBE IIb isoforms play distinct roles in determining the fine structure of amylopectin. A significant reduction in the frequency of branches in amylopectin was noticed only when both SBE IIa and SBE IIb were reduced, whereas there was a significant increase in the branching frequency of amylose when SBE IIb alone was reduced. Functional interactions between SBE isoforms are suggested, and a possible inhibitory role of SBE IIb on other SBE isoforms is discussed

Overview of ImageCLEF 2017: Information extraction from images

This paper presents an overview of the ImageCLEF 2017 evaluation campaign, an event that was organized as part of the CLEF (Conference and Labs of the Evaluation Forum) labs 2017. ImageCLEF is an ongoing initiative (started in 2003) that promotes the evaluation of technologies for annotation, indexing and retrieval for providing information access to collections of images in various usage scenarios and domains. In 2017, the 15th edition of ImageCLEF, three main tasks were proposed and one pilot task: (1) a LifeLog task about searching in LifeLog data, so videos, images and other sources; (2) a caption prediction task that aims at predicting the caption of a figure from the biomedical literature based on the figure alone; (3) a tuberculosis task that aims at detecting the tuberculosis type from CT (Computed Tomography) volumes of the lung and also the drug resistance of the tuberculosis; and (4) a remote sensing pilot task that aims at predicting population density based on satellite images. The strong participation of over 150 research groups registering for the four tasks and 27 groups submitting results shows the interest in this benchmarking campaign despite the fact that all four tasks were new and had to create their own community

Activin B is produced early in antral follicular development and suppresses thecal androgen production

Little is known about the role of activin B during folliculogenesis. This study investigated the expression levels of activin/inhibin subunits (βA, βB, and α), steroid enzyme, and gonadotrophin receptors in theca (TC) and granulosa cells (GC) by QPCR and activin A and B and inhibin A protein levels in follicular fluid (FF) of developing sheep follicles during estrus and anestrus. The effect of activin B on androgen production from primary TC cultures in vitro was also assessed. During folliculogenesis, in anestrus and estrus, FF activin B concentrations and thecal and GC activin βB mRNA levels decreased as follicle diameter increased from 1–3 to >6 mm regardless of estrogenic status. Estrogenic preovulatory follicles had reduced concentrations of FF activins B and A, and TC and GCs expressed higher levels of activin βA mRNA at 3–4 mm, and TCs more inhibin α mRNA at >4 mm stages of development compared with nonestrogenic follicles. Activin B decreased androstenedione production from primary TCs in vitro, an effect blocked by inhibin A. Thus, sheep follicles 1–3 mm in diameter contained high FF levels of activin B, which decreased as the follicle size increased, and, like activin A, suppressed thecal androgen production in vitro, an effect blocked by inhibin. Furthermore, the theca of large estrogenic follicles expressed high levels of inhibin α and activin βA mRNA suggesting local thecal derived inhibin A production. This would inhibit the negative effects of thecal activins B and A ensuring maximum androgen production for enhanced estradiol production by the preovulatory follicle(s)