bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sequential measurement of δ15N, δ13C and δ34S values in archaeological bone collagen at the Scottish Universities Environmental Research Centre (SUERC): A new analytical frontier
Authors: Sayle Kerry L. , Brodie Christopher R. , Cook Gordon T. , Hamilton W. Derek 
Published: April 2019

RationaleThe use of multi‐isotopic analysis (δ15N, δ13C and δ34S values) of archaeological bone collagen to assist in the interpretation of diet, movement and mobility of prehistoric populations is gradually increasing, yet many researchers have traditionally avoided investigating sulphur due to its very low concentrations (<0.3%) in mammalian collagen. For this reason, and as a consequence of analytical detection limits, sulphur is usually measured separately from carbon and nitrogen, which leads to longer analytical times and higher costs.MethodsA Thermo Scientific™ EA IsoLink™ isotope ratio mass spectrometry (IRMS) system, with the ability to rapidly heat a gas chromatography (GC) column and concentrate the sample gas online without cryo‐trapping, was used at the Radiocarbon Laboratory at the Scottish Universities Environmental Research Centre (SUERC). Optimisation of the GC temperature and carrier gas flow rate in the elemental analyser resulted in improved signal‐to‐noise (S/N) ratio and sensitivity for SO2. This allowed for routine sequential N2, CO2 and SO2 measurements on small samples of bone collagen.ResultsImprovements in sample gas transfer to the mass spectrometer allows for sequential δ15N, δ13C and δ34S values to be measured in 1–1.5 mg samples of bone collagen. Moreover, the sensitivity and S/N ratio of the sample gas, especially SO2, is improved, resulting in precisions of ±0.15‰ for δ15N values, ±0.1‰ for δ13C values and ±0.3‰ for δ34S values. Previous instrumentation allowed for the analysis of ~30 unknown samples before undertaking maintenance; however, ~150 unknown samples can now be measured, meaning a 5‐fold increase in sample throughput.ConclusionsThe ability to sequentially measure δ15N, δ13C and δ34S values rapidly in archaeological bone collagen is an attractive option to researchers who want to build larger, more succinct datasets for their sites of interest, at a much‐reduced analytical cost and without destroying larger quantities of archaeological material.
Calibrating temperature reconstructions from fish otolith oxygen isotope analysis for California's critically endangered Delta Smelt
Authors: Willmes Malte , Lewis Levi S. , Davis Brittany E. , Loiselle Liane , James Hannah F. , Denny Christian , Baxter Randall , Conrad J. Louise , Fangue Nann A. , Hung Tien‐Chieh , Armstrong Richard A. , Williams Ian S. , Holden Peter , Hobbs James A. 
Published: April 2019

RationaleOxygen isotope ratios (δ18O values) of fish otoliths (ear bones) are valuable geochemical tracers of water conditions and thermal life history. Delta Smelt (Hypomesus transpacificus) are osmerid forage fish endemic to the San Francisco Estuary, California, USA, that are on the verge of extinction. These fish exhibit a complex life history that allows them to survive in a dynamic estuarine environment; however, a rapidly warming climate threatens this thermally sensitive species. Here we quantify the accuracy and precision of using δ18O values in otoliths to reconstruct the thermal life histories of Delta Smelt.MethodsDelta Smelt were reared for 360 days using three different water sources with different ambient δ18Owatervalues (−8.75‰, −5.28‰, and −4.06‰) and different water temperatures (16.4°C, 16.7°C, 18.7°C, and 20.5°C). Samples were collected after 170 days (n = 28) and 360 days (n = 14) post‐hatch.In situδ18O values were measured from the core of the otolith to the dorsal edge using secondary ion mass spectrometry (SIMS) to reconstruct temporally resolved thermal life histories.ResultsThe δ18Ootolithvalues for Delta Smelt varied as a linear inverse function of water temperature:1000 ln α = 18.39 (±0.43, 1SE)(103TK−1) − 34.56 (±1.49, 1SE)andδ18Ootolith(VPDB) − δ18Owater (VPDB) = 31.34(±0.09, 1SE) − 0.19(±0.01, 1SE) × T ° C. When the ambient δ18Owatervalue is known, this species‐specific temperature‐dependent oxygen isotope fractionation model facilitated the accurate (0.25°C) and precise (±0.37°C, 2σ) reconstruction of the water temperature experienced by the fish. In contrast, the use of existing general fractionation equations resulted in inaccurate temperature reconstructions.ConclusionsThe species‐specific δ18Ootolithfractionation equation allowed for accurate and precise reconstructions of water temperatures experienced by Delta Smelt. Characterization of ambient δ18Owatervalues remains a critical next step for reconstructing thermal life histories of wild Delta Smelt. This tool will provide new insights into habitat utilization, potential thermal refugia, and resilience to future warming for this critically endangered fish.
Reproductive neuroendocrinology of mammalian gonadotropin‐inhibitory hormone
Authors: Ubuka Takayoshi , Tsutsui Kazuyoshi 
Published: April 2019

AbstractBackgroundGonadotropin‐inhibitory hormone (GnIH) was discovered in the Japanese quail brain in 2000 as a hypothalamic neuropeptide that suppresses luteinizing hormone release from cultured quail anterior pituitary.MethodsThe authors investigated the existence of mammalian orthologous peptides to GnIH and their physiological functions in the following 19 years of research.Main findingsMammals have orthologous peptide to GnIH, often described RFamide‐related peptide, expressed in the hypothalamus and gonads. Mammalian GnIH may also suppress gonadotropin synthesis and release by suppressing gonadotropin‐releasing hormone (GnRH) synthesis and release in addition to directly suppressing gonadotropin synthesis and release from the pituitary. Mammalian GnIH may also suppress kisspeptin, a stimulator of GnRH, release. Mammalian GnIH is also expressed in the testis and ovary and suppresses gametogenesis and sex steroid production acting in an autocrine/paracrine manner. Thus, mammalian GnIH may act at all levels of the hypothalamic‐pituitary‐gonadal axis to suppress reproduction. GnIH may be involved in the regulation of puberty, estrous or menstrual cycle, seasonal reproduction, and stress responses.ConclusionStudies suggest that mammalian GnIH is an important neuroendocrine suppressor of reproduction in mammals.
Sensor cascading fault estimation and control for hypersonic flight vehicles based on a multidimensional generalized observer
Authors: Chen Fuyang , Jiang Gengqian , Wen Changyun 
Published: April 2019

SummaryThis study presents a sensor cascading fault estimation and fault‐tolerant control (FTC) for a nonlinear Takagi‐Sugeno fuzzy model of hypersonic flight vehicles. Sensor cascading faults indicate the occurrence of source fault will cause another fault and the interval between them is really short, which makes it difficult to handle them in succession. A novel multidimensional generalized observer is used to estimate faults by integrating constant offset and time‐varying gain faults. Then, a fault‐tolerant controller is used to solve system nonlinearity and sensor fault problems. The observer and controller satisfy the performance index and are robust to external disturbances. A sufficient condition for the existence of observer and controller is derived on the basis of Lyapunov theory. Simulation results indicate the effectiveness of the proposed fault estimation and FTC scheme.
Nonlinear bilateral teleoperators under event‐driven communication with constant time delays
Authors: Liu Yen‐Chen , Hu Shin‐Chen 
Published: April 2019

SummaryBilateral teleoperation systems provide a platform for human operators to remotely manipulate slave robots in engaging various tasks in remote environments. Most of the previous studies in bilateral teleoperation were developed under continuous transmission or periodic communication with fixed data exchanging rates. This paper presents control schemes for bilateral teleoperation systems using nonperiodic event‐driven communication. By using P‐like and PD‐like controllers, this study proposes triggering conditions for teleoperators to reduce network access frequency so that robots only transmit output signals when necessary. Stability and position tracking of the control system are studied, and nonzero minimum interevent time is guaranteed. The proposed event‐driven teleoperation is studied with a velocity estimator to avoid the requirement of velocity information in the controller and triggering condition. Without velocity measurements, the boundedness of tracking errors and stability are ensured for teleoperation systems under event‐driven communication. Simulations and experiments are illustrated to validate the performance of the proposed event‐driven teleoperation systems.
Alternatives to Cryogenic Distillation: Advanced Porous Materials in Adsorptive Light Olefin/Paraffin Separations
Authors: Wang Yuxiang , Peh Shing Bo , Zhao Dan 
Published: April 2019

AbstractAs primary feedstocks in the petrochemical industry, light olefins such as ethylene and propylene are mainly obtained from steam cracking of naphtha and short chain alkanes (ethane and propane). Due to their similar physical properties, the separations of olefins and paraffins—pivotal processes to meet the olefin purity requirement of downstream processing—are typically performed by highly energy‐intensive cryogenic distillation at low temperatures and high pressures. To reduce the energy input and save costs, adsorptive olefin/paraffin separations have been proposed as promising techniques to complement or even replace cryogenic distillation, and growing efforts have been devoted to developing advanced adsorbents to fulfill this challenging task. In this Review, a holistic view of olefin/paraffin separations is first provided by summarizing how different processes have been established to leverage the differences between olefins and paraffins for effective separations. Subsequently, recent advances in the development of porous materials for adsorptive olefin/paraffin separations are highlighted with an emphasis on different separation mechanisms. Last, a perspective on possible directions to push the limit of the research in this field is presented.
Monitoring Nanocrystal Self‐Assembly in Real Time Using In Situ Small‐Angle X‐Ray Scattering
Authors: Lokteva Irina , Koof Michael , Walther Michael , Grübel Gerhard , Lehmkühler Felix 
Published: April 2019

AbstractSelf‐assembled nanocrystal superlattices have attracted large scientific attention due to their potential technological applications. However, the nucleation and growth mechanisms of superlattice assemblies remain largely unresolved due to experimental difficulties to monitor intermediate states. Here, the self‐assembly of colloidal PbS nanocrystals is studied in real time by a combination of controlled solvent evaporation from the bulk solution and in situ small‐angle X‐ray scattering (SAXS) in transmission geometry. For the first time for the investigated system a hexagonal closed‐packed (hcp) superlattice formed in a solvent vapor saturated atmosphere is observed during slow solvent evaporation from a colloidal suspension. The highly ordered hcp superlattice is followed by a transition into the final body‐centered cubic superlattice upon complete drying. Additionally, X‐ray cross‐correlation analysis of Bragg reflections is applied to access information on precursor structures in the assembly process, which is not evident from conventional SAXS analysis. The detailed evolution of the crystal structure with time provides key results for understanding the assembly mechanism and the role of ligand–solvent interactions, which is important both for fundamental research and for fabrication of superlattices with desired properties.
Value co‐creation between foreign firms and indigenous small‐ and medium‐sized enterprises (SMEs) in Kazakhstan's oil and gas industry: The role of information technology spillovers
Authors: Heim Irina , Kalyuzhnova Yelena , Li Weizi , Liu Kecheng 
Published: April 2019

AbstractStudy related to the extractive sector still plays a limited role in the mainstream international business (IB) and management literature, with even less focus on ongoing liberalization and digitalization in the industry. This article was motivated by the question of how collaboration between foreign and indigenous oil and gas (O&G) companies can support small‐sized and medium‐sized indigenous technological development. The main contribution of this article is the development of a model that explains how different actors can cocreate value in the ecosystem of the O&G industry through digital technologies. A three‐stage qualitative–interpretive method based on interviews with industry experts was adopted to build three vignette case studies. This article proposes what companies and the government could do to increase the competitiveness of the local economy, diversify from O&G into high technological industries, and support industrial development through information and communication technologies (ICT).
Methods for the study of innate immunity in Drosophila melanogaster
Authors: Troha Katia , Buchon Nicolas 
Published: April 2019

From flies to humans, many components of the innate immune system have been conserved during metazoan evolution. This foundational observation has allowed us to develop Drosophila melanogaster, the fruit fly, into a powerful model to study innate immunity in animals. Thanks to an ever‐growing arsenal of genetic tools, an easily manipulated genome, and its winning disposition, Drosophila is now employed to study not only basic molecular mechanisms of pathogen recognition and immune signaling, but also the nature of physiological responses activated in the host by microbial challenge and how dysregulation of these processes contributes to disease. Here, we present a collection of methods and protocols to challenge the fly with an assortment of microbes, both systemically and orally, and assess its humoral, cellular, and epithelial response to infection. Our review covers techniques for measuring the reaction to microbial infection both qualitatively and quantitatively. Specifically, we describe survival, bacterial load, BLUD (a measure of disease tolerance), phagocytosis, melanization, clotting, and ROS production assays, as well as efficient protocols to collect hemolymph and measure immune gene expression. We also offer an updated catalog of online resources and a collection of popular reporter lines and mutants to facilitate research efforts.This article is categorized under:
Technologies > Analysis of Cell, Tissue, and Animal Phenotypes
National Performance-Based Research Funding Systems: Constructing Local Perceptions of Research?
Authors: Söderlind Johan , Berg Laila Nordstrand , Lind Jonas Krog , Pulkkinen Kirsi 
Published: April 2019

AbstractIn recent years, performance-based research funding systems (PRFSs) have been introduced in all of the Nordic countries. In this chapter, we compare these systems and explore how their introduction is reflected within universities. Through interviews with academics, managers and administrators, we study how the performance measures of these systems are used at the university level and how that affects research activities. The results indicate that the introduction of PRFSs at the national level have had significant effects at the institutional level. The PRFSs contribute to the institutionalisation and consolidation of research metrics as the main way to describe research performances, and thus as the organising principles of research. Differences are also noted between the countries in the reactions of the university actors, which are believed to be a consequence of the variations of the PRFSs.
External Research Funding and Authority Relations
Authors: Lind Jonas Krog , Hernes Helge , Pulkkinen Kirsi , Söderlind Johan 
Published: April 2019

AbstractThis chapter analyses how the increasing external research project funding has affected the authority over research for managers and researchers in Nordic universities. Drawing on both the qualitative and quantitative data from the FINNUT project, the chapter uses institutional theory to investigate how authority relations between managers and researcher unfold by focusing on the themescontent,time, andpeople. For researchers, the increasing external funding has resulted in some reduction of the authority over research. However, researchers do employ a range of defence mechanisms in order to protect their research freedom. For managers, the results are ambiguous since, on the one hand, their authority over the content and direction of research in their units are limited due to external funding, while, on the other hand, the pressure in general to secure external funding has spurred abudget-maximisationlogic which has helped legitimise a range of managerial control techniques intended to pressure researchers to obtain more external funding.
T-branes and defects
Authors: Marchesano Fernando , Savelli Raffaele , Schwieger Sebastian 
Published: April 2019

AbstractWe study T-branes on compact Kähler surfaces, in the presence of fields localised at curves. If such fields are treated as defects, their vevs induce delta-function sources for the 7-brane background, possibly leading to profiles with poles. We find that the presence of defect sources relaxes the constraints on globally well-defined T-brane configurations, avoiding the obstruction to building them on surfaces of positive curvature. Profiles with poles can be understood, from a 4d viewpoint, as non-trivial vevs for massive modes induced by the defects, and come with their own set of constraints. In the special case of fields localised on a self-intersection curve, we show how to retrieve the Hitchin system with defects from an ordinary global one with enhanced symmetry.
Natives’ Attitudes and Immigrants’ Unemployment Durations
Authors: Keita Sekou , Valette Jérôme 
Published: April 2019

Abstract
In this study, we investigate how the attitude of natives—defined as the perceived trustworthiness of citizens from different countries—affects immigrants’ labor market outcomes in Germany. Evidence in the literature suggests that barriers to economic assimilation might be higher for some groups of immigrants, but the role of natives’ heterogeneous attitudes toward immigrants from different countries of origin has received little attention. Using individual-level panel data from the German Socio-Economic Panel covering the years 1984 to 2014, we apply survival analysis methods to model immigrants’ unemployment durations. We find that lower levels of trust expressed by natives toward the citizens of a given country, measured using Eurobarometer surveys, are associated with increased unemployment durations for immigrants from this country. We show that this result is not driven by origin-specific unobserved heterogeneity and that it is robust to different specifications and alternative explanations.
Application of advanced brain positron emission tomography–based molecular imaging for a biological framework in neurodegenerative proteinopathies
Authors: Perani Daniela , Iaccarino Leonardo , Jacobs Andreas H. ,   IMBI Brain Imaging Working Group, Lammertsma Adriaan A. , Nordberg Agneta , Windhorst Albert D. , Gerhard Alexander , Winkeler Alexandra , Jacobs Andreas H. , Gee Anthony , Kuhnast Bertrand , Halldin Christer , Perani Daniela , Brooks David , Rodriguez‐Vieitez Elena , Turkheimer Federico E. , López‐Picón Francisco , Knudsen Gitte M. , Vercouillie Johnny , Rinne Juha O. , Herholz Karl , Van Laere Koen , Varrone Andrea , Santiago‐Ribeiro Marie Joao , Herth Matthias M. , Carroll Michael A. , Chalon Sylvie , Bottlaender Michel , Hansson Oskar , Edison Paul , Hinz Rainer , Boellaard Ronald , Moresco Rosa Maria , Pappata Sabina 
Published: April 2019

AbstractIntroductionA rapid transition from a clinical‐based classification to a pathology‐based classification of neurodegenerative conditions, largely promoted by the increasing availability of imaging biomarkers, is emerging. The Framework for Innovative Multi‐tracer molecular Brain Imaging, funded by the EU Joint Program ‐ Neurodegenerative Disease Research 2016 “Working Groups for Harmonisation and Alignment in Brain Imaging Methods for Neurodegeneration,” aimed at providing a roadmap for the applications of established and new molecular imaging techniques in dementia.MethodsWe consider current and future implications of adopting a pathology‐based framework for the use and development of positron emission tomography techniques.ResultsThis approach will enhance efforts to understand the multifactorial etiology of Alzheimer's disease and other dementias.DiscussionThe availability of pathology biomarkers will soon transform clinical and research practice. Crucially, a comprehensive understanding of strengths and caveats of these techniques will promote an informed use to take full advantage of these tools.
Beryllium-10 dating of the Foothills Erratics Train in Alberta, Canada, indicates detachment of the Laurentide Ice Sheet from the Rocky Mountains at ~15 ka
Authors: Margold Martin , Gosse John C. , Hidy Alan J. , Woywitka Robin J. , Young Joseph M. , Froese Duane 
Published: April 2019

AbstractThe Foothills Erratics Train consists of large quartzite blocks of Rocky Mountains origin deposited on the eastern slopes of the Rocky Mountain Foothills in Alberta between ~53.5°N and 49°N. The blocks were deposited in their present locations when the western margin of the Laurentide Ice Sheet (LIS) detached from the local ice masses of the Rocky Mountains, which initiated the opening of the southern end of the ice-free corridor between the Cordilleran Ice Sheet and the LIS. We use10Be exposure dating to constrain the beginning of this decoupling. Based on a group of 12 samples well-clustered in time, we date the detachment of the western LIS margin from the Rocky Mountain front to ~14.9 ± 0.9 ka. This is ~1000 years later than previously assumed, but a lack of a latitudinal trend in the ages over a distance of ~500 km is consistent with the rapid opening of a long wedge of unglaciated terrain portrayed in existing ice-retreat reconstructions. A later separation of the western LIS margin from the mountain front implies higher ice margin–retreat rates in order to meet the Younger Dryas ice margin position near the boundary of the Canadian Shield ~2000 years later.
Neural networks: from image recognition to tokamak plasma tomography
Authors: Jardin Axel , Bielecki Jakub , Mazon Didier , Dankowski Jan , Król Krzysztof , Peysson Yves , Scholz Marek 
Published: April 2019

AbstractIn this paper, the possibility of using neural networks for fast tomographic reconstructions of tokamak plasma soft X-ray (SXR) emissivity is investigated. Indeed, the radiative cooling of heavy impurities like tungsten could be detrimental for the plasma core performances of ITER, thus developing robust and fast SXR diagnostic tools is a crucial issue to monitor the impurities and to mitigate in real-time their central accumulation. As preliminary work, a database of emissivity phantoms with associated synthetic measurements is used to train the neural network to solve the inversion problem. The inversion method, training process, and first tomographic reconstructions are presented with the perspectives about our future work.
Discrete derivative asymptotics of the β-Hermite eigenvalues
Authors: Goel Gopal , Ahn Andrew 
Published: April 2019

AbstractWe consider the asymptotics of the difference between the empirical measures of the β-Hermite tridiagonal matrix and its minor. We prove that this difference has a deterministic limit and Gaussian fluctuations. Through a correspondence between measures and continual Young diagrams, this deterministic limit is identified with the Vershik–Kerov–Logan–Shepp curve. Moreover, the Gaussian fluctuations are identified with a sectional derivative of the Gaussian free field.