bluuebunny/crossref_metadata_2025 huggingface dataset:
Parallel Frequency Acquisition Algorithm for BeiDou Software Receiver Based on Coherent Downsampling
Authors: Zeng Qingxi , Gao Chang , Qiu Wenqi , Zhou Zhaihe , Lyu Chade
Published: August 2019

The time it takes to acquire a satellite signal is one of the most important parameters for a Global Navigation Satellite System (GNSS) receiver. The Parallel Frequency space search acquisition Algorithm (PFA) runs faster than the Parallel Code phase search acquisition Algorithm (PCA) when the approximate phase of Pseudo-Random Noise (PRN) code and the approximate value of a Doppler shift are known. However, a large amount of data is needed to be dealt with by the Fast Fourier Transform (FFT) in a traditional PFA algorithm because it processes a narrow-band signal with the initial sampling frequency after the PRN code is stripped. In order to reduce the computational complexity of the traditional PFA algorithm, a down-conversion module and a downsampling module were added to the traditional PFA in the work reported here. Experiments demonstrated that this method not only succeeded in acquiring BeiDou B1I signals, but also the time for acquirement was reduced by at least 80% with the modified PFA algorithm compared with the traditional PFA algorithm. The loss in Signal-to-Noise Ratio (SNR) did not exceed 0·5 dB when the number of coherent points was less than 500.
The expressive turn of international criminal justice: A field in search of meaning
Authors: Sander Barrie
Published: August 2019

As the glow that accompanied the kinetic judicialization of the field of international criminal justice has faded over time, scholars have increasingly turned to expressivist strands of thought to justify, assess, and critique the practices of international criminal courts. This expressive turn has been characterized by a heightened concern for the pedagogical value and legitimating qualities of international criminal courts. This article develops a unique typology of expressivist perspectives within the field of international criminal justice, distinguishing between three strands of expressivism:instrumentalexpressivism, which concerns the justification of different practices of international criminal courts in terms of the instrumental value of their expressive qualities;interpretiveexpressivism, which concerns the identification of expressive avenues for improving the sociological legitimacy of international criminal courts; andcriticalexpressivism, which concerns the illumination of the expressive limits of international criminal courts, as well as unveiling the configurations of power that underpin the messages and narratives constructed within such courts in different institutional contexts. Reflecting on the limitations of these perspectives, the article elaborates a nascent strand of expressivism –strategicexpressivism – which concerns whether and how different actors in the field may harness the expressive power of international criminal justice in line with their strategic social and political agendas.
A review of the putative causal mechanisms associated with lower macular pigment in diabetes mellitus
Authors: Scanlon Grainne , Loughman James , Farrell Donal , McCartney Daniel
Published: August 2019

Macular pigment (MP) confers potent antioxidant and anti-inflammatory effects at the macula, and may therefore protect retinal tissue from the oxidative stress and inflammation associated with ocular disease and ageing. There is a body of evidence implicating oxidative damage and inflammation as underlying pathological processes in diabetic retinopathy. MP has therefore become a focus of research in diabetes, with recent evidence suggesting that individuals with diabetes, particularly type 2 diabetes, have lower MP relative to healthy controls. The present review explores the currently available evidence to illuminate the metabolic perturbations that may possibly be involved in MP’s depletion. Metabolic co-morbidities commonly associated with type 2 diabetes, such as overweight/obesity, dyslipidaemia, hyperglycaemia and insulin resistance, may have related and independent relationships with MP. Increased adiposity and dyslipidaemia may adversely affect MP by compromising the availability, transport and assimilation of these dietary carotenoids in the retina. Furthermore, carotenoid intake may be compromised by the dietary deficiencies characteristic of type 2 diabetes, thereby further compromising redox homeostasis. Candidate causal mechanisms to explain the lower MP levels reported in diabetes include increased oxidative stress, inflammation, hyperglycaemia, insulin resistance, overweight/obesity and dyslipidaemia; factors that may negatively affect redox status, and the availability, transport and stabilisation of carotenoids in the retina. Further study in diabetic populations is warranted to fully elucidate these relationships.
Mitochondrial cell-free DNA secreted from porcine granulosa cells
Authors: Kansaku Kazuki , Munakata Yasuhisa , Shirasuna Koumei , Kuwayama Takehito , Iwata Hisataka
Published: August 2019

Several studies have proposed that cell-free DNA (cfDNA) is a potential biomarker present in follicular fluid (FF) for oocyte quality. Recently we reported that mitochondria-derived cfDNA (mt-cfDNA) closely reflects the amount of cfDNA in FFs. The present study investigated the mechanism regulating mt-cfDNA secretion from porcine granulosa cells. Oocytes and cumulus cell complexes or granulosa cells (GCs) were cultured in maturation medium for 24 or 48 h respectively. Then, nuclear-derived cell-free DNA (n-cfDNA) or mt-cfDNA contents in the spent medium were examined using real-time polymerase chain reaction. When 10 μM of MG132, a proteasome inhibitor, was added to the culture medium, cellular viability of both COCs and GCs decreased and n-cfDNA significantly increased in the culture medium, whereas mt-cfDNA significantly decreased. Supplementation of the culture medium with GW4869, an inhibitor of intracellular vesicle formation, significantly decreased the mt-cfDNA, whereas no effect was observed on n-cfDNA in the medium of both COCs and GCs. Furthermore, the addition of bafilomycin, an inhibitor of autophagy to the culture medium significantly increased mt-cfDNA in the culture medium. After filtration (0.22 μm) and centrifugation (23,000g), the mt-cfDNA content of the medium decreased significantly. In conclusion, the proteasomal mitochondrial quality control system is upstream of mt-cfDNA secretion and autophagy plays a role in cellular digestion of mitochondrial DNA in the cytoplasm. It is further suggested that dsDNA is enclosed in certain vesicles or associated with small molecules and secreted into the medium.
Coevolution of resistance to PPO inhibitors in waterhemp (Amaranthus tuberculatus) and Palmer amaranth (Amaranthus palmeri)
Authors: Lillie Kathryn J. , Giacomini Darci A. , Green Jonathan D. , Tranel Patrick J.
Published: August 2019

The first case of evolved protoporphyrinogen oxidase (PPO)-inhibitor resistance was observed in 2001 in common waterhemp [Amaranthus tuberculatus (Moq.) Sauer var. rudis (Sauer) Costea and Tardif]. This resistance in A. tuberculatus is most commonly conferred by deletion of the amino acid glycine at the 210th position (ΔGly-210) of the PPO enzyme (PPO2) encoded by PPX2. In a field in Kentucky in 2015, inadequate control of Amaranthus plants was observed following application of a PPO inhibitor. Morphological observations indicated that survivors included both A. tuberculatus and Palmer amaranth (Amaranthus palmeri S. Watson). Research was conducted to confirm species identities and resistance and then to determine whether resistance evolved independently in the two species or via hybridization. Results from a quantitative PCR assay based on the ribosomal internal transcribed spacer confirmed that both A. tuberculatus and A. palmeri coexisted in the field. The mutation conferring ΔGly-210 in PPO2 was identified in both species; phylogenetic analysis of a region of PPX2, however, indicated that the mutation evolved independently in the two species. Genotyping of greenhouse-grown plants that survived lactofen indicated that all A. tuberculatus survivors, but only a third of A. palmeri survivors, contained the ΔGly-210 mutation. Consequently, A. palmeri plants were evaluated for the presence of an arginine to glycine or methionine substitution at position 128 of PPO2 (Arg-128-Gly and Arg-128-Met). The Arg-128-Gly substitution was found to account for resistance that was not accounted for by the ΔGly-210 mutation in plants from the A. palmeri population. Results from this study provide a modern-day example of both parallel and convergent evolution occurring within a single field.
5-Hydroxymethylfurfural and α-ketoglutaric acid supplementation increases oxygen saturation during prolonged exercise in normobaric hypoxia
Authors: Kössler Florian , Mair Lukas , Burtscher Martin , Gatterer Hannes
Published: August 2019

Abstract. This double-blinded, randomized and placebo-controlled, crossover study investigated whether α-ketoglutaric-acid (α-KG) and 5-hydroxymethylfurfural (5-HMF) supplementation improves exercise performance in hypoxia and affects physiological responses during the exercise task. Eight moderately trained male participants (age: 25.3 ± 2.0 y, VO2max: 48.0 ± 8.3 ml/min/kg) performed an incremental exercise test to exhaustion in normoxia and two 2-hour cycle time trial (TT) tests in hypoxia (3,500 m) each separated by 1-week. Prior to the TT, participants supplemented with either α-KG and 5-HMF or placebo (random order). Supplementation did not improve TT performance at altitude and did not affect heart rate, effort perception and oxidative stress levels (p > 0.05). Oxygen saturation (SpO2) was enhanced during the α-KG and 5-HMF supplementation trial (79.5 ± 3.3 vs. 78.2 ± 3.7%, p = 0.026). Even though TT performance was unaffected, the enhanced SpO2– possibly originated from changed O2-affinity – deserves further consideration as the exercise performance decline at altitude is strongly linked to the SpO2decline. The inclusion of moderately fit participants, not specifically cycle trained, might have prevented any visible performance enhancement.
Replication of Study 1 in “Differentiating Social and Personal Power” by Lammers, Stoker, and Stapel (2009)
Authors: Mayiwar Lewend , Lai Linda
Published: August 2019

Abstract. We performed an independent, direct, and better powered ( N = 295) replication of Study 1, an experiment ( N = 113) by Lammers, Stoker, and Stapel (2009) . Lammers and colleagues distinguished between social power (influence over others) and personal power (freedom from the influence of others), and found support for their predictions that the two forms of power produce opposite effects on stereotyping, but parallel effects on behavioral approach. Our results did not replicate the effects on behavioral approach, but partially replicated the effects on stereotyping. Compared to personal power, social power produced less stereotyping, but neither form of power differed significantly from the control condition, and effect sizes were considerably lower than the original estimates. Potential explanations are discussed.
Social and Personal Power: A Closer Examination
Authors: Lammers Joris , Stoker Janka I.
Published: August 2019

Abstract. We thank Mayiwar and Lai (2019) for conducting a replication of Study 1 in Lammers, Stoker, and Stapel (2009) but disagree with their conclusions. Instead, we conclude that their results largely support ours. The results replicate the theoretical distinction between social and personal power, replicate that recalling social versus personal power produces dissimilar levels of stereotyping, and replicate that they produce similar levels of behavioral approach orientation. We discuss the weaker results on stereotyping as the result of the use of an unreliable measure and conclude that despite this, the data are consistent with the possibility of medium-sized effects. We discuss the null-effects on behavioral approach (compared to control) as the result of a change in instructions. We end with a discussion on the implications for the social–personal power distinction and the power literature in general, with a particular focus on how future replication efforts may provide even greater insight.
Moon Sheds Light on Early Solar Spin
Authors: Redd Nola
Published: August 2019

Lunar samples reveal that the Sun spun relatively slowly in its first billion years and blasted the Earth and Moon with coronal mass ejections.
Earthquakes Shake Up Groundwater Systems
Authors: Morton Mary
Published: August 2019

Increased permeability temporarily boosts water flow.
Winter Sea Ice Export From the Beaufort Sea as a Preconditioning Mechanism for Enhanced Summer Melt: A Case Study of 2016
Authors: Babb D. G. , Landy J. C. , Barber D. G. , Galley R. J.
Published: August 2019

During September 2016 an ice‐free Beaufort Sea was observed for only the second time. Like previous regional sea ice minima (1998, 2008, and 2012), seasonal preconditioning of the ice pack toward younger, thinner ice types contributed to premature breakup that accelerated the ice‐albedo feedback and enhanced summer melt. In 2016, anomalously high sea ice export and ice pack divergence during February and April promoted the unusual widespread formation of new ice within the Beaufort. Thin ice types reached a peak regional concentration of 30% in March, when the ice cover is typically dominated by thick first‐year and multiyear sea ice. Combined CryoSat‐2 and Soil Moisture and Ocean Salinity (SMOS) data indicate that the regional ice volume plateaued from December to March as export offset ice growth and ultimately culminated in a −30% volume anomaly in April 2016. This atypically thin ice cover broke up 7 weeks earlier than average, with open water forming not only within coastal flaw leads but also within the offshore pack ice. By July 2016, vast areas of open water within the highly fractured ice cover accelerated the ice‐albedo feedback and led to rapid melt. Though maintaining a partial ice cover during summer throughout the observational record, significant negative trends in September sea ice area within the Beaufort are now punctuated by two recent ice‐free Septembers (2012 and 2016). As the Beaufort transitions toward a seasonally ice‐free sea, we examine the role of winter preconditioning through sea ice transport and its growing importance within an increasingly seasonal and mobile Arctic ice cover.
Modeling Blowing Snow Over the Tibetan Plateau With the Community Land Model: Method and Preliminary Evaluation
Authors: Xie Zhipeng , Hu Zeyong , Ma Yaoming , Sun Genhou , Gu Lianglei , Liu Shuang , Wang Yidan , Zheng Huixuan , Ma Weiqiang
Published: August 2019

Snow cover in mountainous terrain plays an important role in regional and global water and energy balances, climate change, and ecosystems. Blowing snow is a frequent and important weather phenomenon over the Tibetan Plateau (TP); however, this process is neglected in most current land surface models, despite the consequential role it plays in the land surface and atmospheric water and energy budgets. In this paper, we present a blowing snow model PIEKTUK coupled with the Community Land Model (CLM4.5) to provide a better estimate of the snow dynamics for the consideration of snow redistribution induced by wind. Two simulations with a 0.065° spatial resolution were performed in 2010 over the TP, namely, a sensitivity experiment with the inclusion of blowing snow effects (CLM_BS) and a control run with the original model (CLM). A specific objective of this study was to evaluate the improvements in the simulations of snow dynamics and other key variables in surface energy partitioning provided by the coupled model, such as the surface albedo and land surface temperature (LST). Compared with a variety of remote‐sensing observations, the results show that the surface snow cover, snow depth, and surface albedo can be better reproduced in most of the TP region by CLM_BS than by the original CLM, particularly in the Kunlun Mountains, Hoh Xil area, and the southwestern TP. In areas with reduced bias, variations in the monthly mean snow cover fraction can be reflected particularly well by CLM_BS. For LST, however, a significant decrease in the nighttime LST bias was detected in CLM_BS, while the bias in the daytime LST increases. The results show considerable potential for the inclusion of the blowing snow process to promote the modeling of snow dynamics and land‐atmosphere interactions on the TP.
Assessing the Intrinsic Uncertainty and Structural Stability of Planetary Models: 1. Parameterized Thermal‐Tectonic History Models
Authors: Seales Johnny , Lenardic Adrian , Moore William B.
Published: August 2019

Thermal history models, historically used to understand Earth's geologic history, are being coupled to climate models to map conditions that allow planets to maintain life. However, the lack of structural uncertainty assessment has blurred guidelines for how thermal history models can be used toward this end. Structural uncertainty is intrinsic to the modeling process. Model structure refers to the cause and effect relations that define a model and are assumed to adequately represent a particular real world system. Intrinsic/structural uncertainty is different from input and parameter uncertainties (which are often evaluated for thermal history models). A full uncertainty assessment requires that input/parametric and intrinsic/structural uncertainty be evaluated (one is not a substitute for the other). We quantify the intrinsic uncertainty for several parameterized thermal history models (a subclass of planetary models). We use single perturbation analysis to determine the reactance time of different models. This provides a metric for how long it takes low‐amplitude, unmodeled effects to decay or grow. Reactance time is shown to scale inversely with the strength of the dominant model feedback (negative or positive). A perturbed physics analysis is then used to determine uncertainty shadows for model outputs. This provides probability distributions for model predictions. It also tests the structural stability of a model (do model predictions remain qualitatively similar, and within assumed model limits, in the face of intrinsic uncertainty?). Once intrinsic uncertainty is accounted for, model outputs/predictions and comparisons to observational data should be treated in a probabilistic way.
Intrabody against prolyl hydroxylase 2 promotes angiogenesis by stabilizing hypoxia-inducible factor-1α
Authors: Zhao Liangzhong , Liu Ziyu , Yang Fang , Zhang Ying , Xue Ying , Miao Haipeng , Liao Xiangzhi , Huang Hongli , Li Guiying
Published: August 2019

Hypoxia-inducible factor (HIF)-1α is a crucial transcription factor that regulates the expression of target genes involved in angiogenesis. Prolyl hydroxylase 2 (PHD2) dominantly hydroxylates two highly conserved proline residues of HIF-1α to promote its degradation. This study was designed to construct an intrabody against PHD2 that can inhibit PHD2 activity and promote angiogenesis. Single-chain variable fragment (scFv) against PHD2, INP, was isolated by phage display technique and was modified with an endoplasmic reticulum (ER) sequence to obtain ER-retained intrabody against PHD2 (ER-INP). ER-INP was efficiently expressed and bound to PHD2 in cells, significantly increased the levels of HIF-1α, and decreased hydroxylated HIF-1α in human embryonic kidney cell line (HEK293) cells and mouse mononuclear macrophage leukaemia cell line (RAW264.7) cells. ER-INP has shown distinct angiogenic activity both in vitro and in vivo, as ER-INP expression significantly promoted the migration and tube formation of human umbilical vein endothelial cells (HUVECs) and enhanced angiogenesis of chick chorioallantoic membranes (CAMs). Furthermore, ER-INP promoted distinct expression and secretion of a range of angiogenic factors. To the best of our knowledge, this is the first study to report an ER-INP intrabody enhancing angiogenesis by blocking PHD2 activity to increase HIF-1α abundance and activity. These results indicate that ER-INP may play a role in the clinical treatment of tissue injury and ischemic diseases in the future.
Lateral fluid-percussion injury leads to pituitary atrophy in rats
Authors: Anwer Mehwish , Immonen Riikka , Hayward Nick M. E. A. , Ndode-Ekane Xavier Ekolle , Puhakka Noora , Gröhn Olli , Pitkänen Asla
Published: August 2019

Traumatic brain injury (TBI) causes neuroendocrine dysregulation in up to 40% of humans, which is related to impaired function of the hypothalamo-hypophyseal axis and contributes to TBI-related co-morbidities. Our objective was to investigate whether hypophyseal atrophy can be recapitulated in rat lateral fluid-percussion injury model of human TBI. High-resolution structural magnetic resonance images (MRI) were acquired from rats at 2 days and 5 months post-TBI. To measure the lobe-specific volumetric changes, manganese-enhanced MRI (MEMRI) scans were acquired from rats at 8 months post-TBI, which also underwent the pentylenetetrazol (PTZ) seizure susceptibility and Morris water-maze spatial memory tests. MRI revealed no differences in the total hypophyseal volume between TBI and controls at 2 days, 5 months or 8 months post-TBI. Surprisingly, MEMRI at 8 months post-TBI indicated a 17% reduction in neurohypophyseal volume in the TBI group as compared to controls (1.04 ± 0.05 mm3 vs 1.25 ± 0.05 mm3, p < 0.05). Moreover, neurohypophyseal volume inversely correlated with the number of PTZ-induced epileptiform discharges and the mean latency to platform in the Morris water-maze test. Our data demonstrate that TBI leads to neurohypophyseal lobe-specific atrophy and may serve as a prognostic biomarker for post-TBI outcome.
The Skin Aging Exposome
Authors: Sondenheimer K. , Haarmann-Stemmann T. , Schikowski T. , Krutmann J.
Published: August 2019

The totality of non-genetic, mainly environmental factors a human being is exposed to from conception to death is summarized by the term ‘exposome’. This exposome concept aims to better understand the influence of all external and internal factors, their interaction with each other and with genetic factors on the human body. Skin is a barrier organ and thus research on the skin exposome is of obvious relevance. In this state-of-the-art review, we summarize existing information on the skin exposome by focusing on skin aging as a trait present in healthy skin.
Epidermal Stem Cells and Dermal–Epidermal Junction
Authors: Aumailley Monique , Niemann Catherin
Published: August 2019

Aging of mammalian skin results from two distinct biological processes: intrinsic and extrinsic mechanisms of skin aging. Exposure to solar ultraviolet (UV) radiation (photoaging) is the major extrinsic assault accelerating the normal aging process. The epidermis constitutes the outermost layer of the skin and thus is constantly challenged by harmful environmental assaults. As an integral part of the skin barrier, the epidermis ensures protection by its robust stratified architecture and integrated epidermal appendages. The epidermal tissue is further stabilized by specialized zones connecting the epidermis to the underlying dermal tissue. These dermal–epidermal junctions (DEJs) consist of a network of different intracellular, transmembrane and extracellular proteins that together fulfil crucial biological and structural functions. Above all, the epidermis relies on tissue stem cells to maintain homeostasis and to guarantee tissue repair following damage. Hence, proper stem cell function is pivotal and required to sustain assaults. In this review we present important structural and functional aspects of the DEJ and its role in aging of the skin. We also discuss implications and protective mechanisms of UV-irradiated epidermis, highlighting stem cell-specific surveillance mechanisms and the important function of the stem cell niche.
Solar Elastosis and the Dermal Elastic Fibre Network
Authors: Langton Abigail K. , Watson Rachel E. B.
Published: August 2019

This chapter focuses on the cutaneous elastic fibre system. In addition to a detailed description of its architecture, we include information on the synthesis and deposition of elastic fibres and what happens to the organisation of elastic fibres in response to chronic ultraviolet radiation. The chapter also examines our current understanding of the potential mechanisms responsible for elastic fibre remodelling, drawing information from in vitro and experimental model systems, including clinical studies in humans.
Do Proteoglycans Mediate Chronic Photoaging?
Authors: Oh Jang-Hee , Chung Jin Ho
Published: August 2019

As well as collagen and elastin, glycosaminoglycans (GAGs) and proteoglycans (PGs) are abundant components in the extracellular matrix (ECM) in the skin. Hyaluronic acid (HA), dermatan sulfate (DS), chondroitin sulfate (CS), heparan sulfate (HS), heparin (HP), and keratin sulfate (KS) are six known members of GAGs, and numbers of their own partner PGs have been reported, except HA. Their structural and physiological roles are being revealed, and they are focused in these days as one of new targets for preventing or recovering skin aging. Understanding the complex interaction of GAGs and PGs with ECM components, specially, collagen and elastic fibers, may help us find new ideas to overcome the skin aging phenomenon. In this review, aging-related change of collagen and elastic fibers and glycosaminoglycan synthesis were simply explained as background, and the structural and physiological roles of skin-abundant GAGs and PGs, including hyaluronic acid, DS-PGs (decorin, biglycan, and others), CS-PGs (versican, CD44, and others), HS-PGs (perlecan and others), KS-PGs (lumican, osteoglycin, and fibromodulin), and their skin aging-related changes and possible involvements in the development of phenotypes of photoaging were summarized.
Cosmeceuticals
Authors: Bradley Eleanor , Bell Mike , Draelos Zoe
Published: August 2019

Cosmeceuticals, defined for the purpose of this chapter as highly efficacious functional ingredients or final products, are becoming more commonplace in the skincare market globally, in particular within the anti-aging category. Many of these ingredients or products aim to improve the clinical features of photoaged skin such as wrinkles and pigmentation through targeting the underlying causes of these clinical features, with increasingly comprehensive efficacy and mechanistic data to support these claims. In this chapter, we review the main classes of cosmeceuticals, the biological endpoints they target together with the evidence that supports their clinical efficacy.
Retro-biosynthetic construction of corynanthe alkaloid skeletons from rhynchophylline alkaloids
Authors: Tong Xiaogang , Shi Bingfei , Liu Qian , Huo Yanman , Xia Chengfeng
Published: August 2019

Corynanthe alkaloids could be generated from rhynchophylline alkaloids in a retro-biosynthetic manner via a Wagner–Meerwein rearrangement.
High catalytic activity of Rh nanoparticles generated from cobaltocene and RhCl3 in aqueous solution
Authors: Wang Wenjuan , Ciganda Roberto , Wang Changlong , Escobar Ane , Martinez-Villacorta Angel M. , Ramirez Maria de los Angeles , Hernández Ricardo , Moya Sergio E. , Ruiz Jaime , Hamon Jean-René , Astruc Didier
Published: August 2019

Cobalticinium chloride-stabilized RhNPs are very efficient catalysts for hydrolysis of H3N-BH3, reduction of 4-NP, hydrogenation of benzene and transfer hydrogenation.
Incorporation of organic and inorganic impurities into the lattice of metastable vaterite
Authors: Seknazi Eva , Mijowska Sylwia , Polishchuk Iryna , Pokroy Boaz
Published: August 2019

Highly substituted Mg-vaterite and Ba-vaterite were synthesized in the presence of aspartic acid and characterized by means of synchrotron XRD.
Imaging and characterizing fluid invasion in micro-3D printed porous devices with variable surface wettability
Authors: Li HongXia , Zhang TieJun
Published: August 2019

We experimentally characterized the wettability-dependent fluid invasion dynamics, including transient interfacial meniscus, multiphase flow path, and fluid trapping behaviors, in 3D-printed transparent rock micromodels with 2 μm feature resolution.
Second Language Learners' Listener Impressions of Foreigner-Directed Speech
Authors: Bobb Susan C. , Mello Kristin , Turco Emily , Lemes Larissa , Fernandez Erika , Rothermich Kathrin
Published: August 2019

Background

According to sociolinguistic frameworks such as Communication Accommodation Theory, English native speakers modify their speech to meet the communicative needs of non-native speakers (Beebe & Giles, 1984). However, when foreigner-directed speech is used inappropriately, it may lead to overaccommodation, which in turn can act counterproductively toward communicative goals.

Purpose

To date, much of the research on foreigner-directed speech toward non-native speakers has focused on its acoustic parameters, but few studies have examined how second language learners interpret it emotionally and pragmatically.

Method

This study asked 36 English second language learners to listen to four types of speech accommodation styles (casual, clear, infant-directed, and foreigner-directed) spoken by four different speakers. Their task was to evaluate the extent to which the speaker was easy to understand, competent, condescending, friendly, and respectful.

Results

Acoustic analyses of the speech stimuli showed that speakers used distinct acoustic cues for each speech accommodation style, for example, slower speech rate for foreigner-directed speech. The rating results show that second language learners of English judged casual speech as least intelligible, least competent, and least friendly compared to all other speech types. Respectfulness ratings show that participants perceived casual speech as less respectful compared to clear speech and infant-directed speech, but not foreigner-directed speech. However, no effects were found for condescension.

Conclusion

The results suggest second language learners in the current experiment generally perceived speech accommodation positively.
Stability regions of fractional systems in the space of perturbed orders
Authors: Rapaić Milan R. , Malti Rachid
Published: August 2019

When dealing with fractional order systems, perturbations in differentiation orders arise frequently due to issues with floating point arithmetics, or due to imprecisions of various order estimation algorithms. This study establishes new results regarding stability/instability of fractional systems with perturbed differentiation orders, knowing the related properties of their unperturbed counterparts. First of all, starting from a point in the space of differentiation orders, sufficient stability/instability conditions of all systems with differentiation orders varying along a line segment with a prescribed direction are established. Then, a continuation procedure is developed allowing computation of the maximum perturbation (along some given direction) which guarantees that the number of zeros in the closed right‐half plane of the characteristic function remain unchanged. Finally, sufficient conditions are established guaranteeing stability/instability of all systems having differentiation orders within a domain. The established results allow concluding on the stability of incommensurate fractional transfer functions. They are illustrated by a number of examples, including an experimental one.
Development of UPFC operating constraints enforcement approach for power flow control
Authors: Ebeed Mohamed , Kamel Salah , Yu Juan , Jurado Francisco
Published: August 2019

This study proposes a comprehensive modelling for a unified power flow controller (UPFC) into a Newton–Raphson load flow algorithm. The developed UPFC model is based on the power injection approach considering four control modes to control the voltage magnitude of a specific bus, the active and reactive powers flow in a transmission line concurrently or selectively. The developed model avoids the modifications of the main part of the load flow algorithm (Jacobian matrix). This can be achieved by transforming the voltage sources of UPFC equivalent circuit into two injected loads at its sending and receiving buses. The required control values can be achieved by updating these injected loads as a function of them. Consequently, the complexities of incorporating UPFC in load flow algorithm are significantly reduced. The operating constraints of the UPFC model are enforced using the developed approach based on modifying and updating the specified values as a function of their maximum limits. The developed model with constraints handling approach is validated using standard IEEE 14‐bus, 30‐bus, and 118‐bus test systems. The obtained results demonstrate the effectiveness of the developed model and its superiority to other reported conventional methods.
Fault location in low‐voltage direct current network based on auxiliary injection unit
Authors: Jiang Shan , Fan Chunju , Huang Ning
Published: August 2019

Fault location plays an important role in accelerating fault clearance and grid recovery, which greatly improves the reliability and robustness of low‐voltage direct current distribution network. A fault location method based on auxiliary injection unit (AIU) is proposed in this study with respect to its basic structure and principle. With single terminal information, the proposed method allows low requirement of sampling frequency and enhances the tolerance to fault resistance by utilising the characteristic of AIU. Furthermore, design criteria of components in AIU are discussed in detail. Optimised parameters contribute to better performance in estimating fault distance. Numerous simulations demonstrate that the proposed method can realise accurate fault location with fault distance and fault resistance varying in a wide range.
MMSE‐based waveform design for the distributed MIMO radar in spectrally crowded environments
Authors: Tang Bo , Zhang Ning , Zhang Shuo , Huang Zhongrui
Published: August 2019

This study investigates the waveform design problem for a distributed multiple‐input‐multiple‐output (MIMO) radar operating in spectrally crowded environments. The goal is to synthesise waveforms to minimise the target estimation error and improve the spectral coexistence with other radio frequency systems (e.g. communication systems). To this end, a waveform design problem based on minimising the mean square error (MSE) of target estimation has been formulated under the energy and spectral constraints. An algorithm to synthesise the optimal spectrally constrained waveforms with the minimum MSE has been proposed. It has been shown that the synthesised waveforms have superior estimation performance (in terms of MSE) and ensure significantly enhanced spectral compatibility.
Low‐complexity DOA estimation method for a co‐prime linear array
Authors: Wu Xuchen , Yang Xiaopeng , Han Bowen , Xu Feng
Published: August 2019

The problem of direction‐of‐arrival (DOA) estimation for a co‐prime linear array is researched. A low‐complexity DOA estimation method is proposed. The co‐prime array is decomposed into two sparse uniform linear sub‐arrays whose inter‐element spacing meets the co‐prime condition. Then the received signals of the two sub‐arrays are processed for statistical signal processing. Although the DOA estimation based on the under‐sampled signal will produce phase ambiguity, the sparse array element spacing that satisfies the co‐prime condition makes the phase ambiguity have certain periodic rules. Finally, the unique solution corresponding to the true DOA can be obtained in the phase ambiguities of the two sub‐arrays through the application of the co‐prime nature. Simulation results validate the effectiveness of the proposed method.
Model for Population III microquasars
Authors: Sotomayor Checa P. , Romero G. E.
Published: August 2019

Context.Current simulations indicate that the first stars were formed predominantly in binary systems. Studying the contribution of the first accreting binary systems to the reionization and heating of the intergalactic medium requires formulating a concrete model for Population III microquasars.

Aims.We aim at constructing a complete model for microquasars with a Population III donor star.

Methods.We considered that the mass loss of the star is exclusively caused by the spill of matter through the Roche lobe toward the black hole. We calculated the spectral energy distribution of the radiation produced by the accretion disk, the radiation-pressure-driven wind, and the relativistic particles in the jets, within the framework of a lepto-hadronic model. In addition, we estimated the effect on the reionization by the first microquasars.

Results.We determine that Population III microquasars are powerful sources of ultraviolet radiation produced by the winds of their super-critical disks, and that they generate a broadband nonthermal emission in jets.

Conclusions.Our results indicate that microquasars in the early Universe could have been important for the reionization and heating of the intergalactic medium.
Gaia DR2 white dwarfs in the Hercules stream
Authors: Torres Santiago , Cantero Carles , Camisassa María E. , Antoja Teresa , Rebassa-Mansergas Alberto , Althaus Leandro G. , Thelemaque Thomas , Cánovas Héctor
Published: August 2019

Aims. We analyzed the velocity space of the thin- and thick-disk Gaia white dwarf population within 100 pc by searching for signatures of the Hercules stellar stream. We aimed to identify objects belonging to the Hercules stream, and by taking advantage of white dwarf stars as reliable cosmochronometers, to derive a first age distribution.

Methods. We applied a kernel density estimation to the UV velocity space of white dwarfs. For the region where a clear overdensity of stars was found, we created a 5D space of dynamic variables. We applied a hierarchichal clustering method, HDBSCAN, to this 5D space, and identified those white dwarfs that share similar kinematic characteristics. Finally, under general assumptions and from their photometric properties, we derived an age estimate for each object.

Results. The Hercules stream was first revealed as an overdensity in the UV velocity space of the thick-disk white dwarf population. Three substreams were then found: Hercules a and Hercules b, formed by thick-disk stars with an age distribution that peaked 4 Gyr in the past and extends to very old ages; and Hercules c, with a ratio of 65:35 of thin to thick stars and a more uniform age distribution that is younger than 10 Gyr.
Dynamic analysis of beams on fractional viscoelastic foundation subject to a variable speed moving load
Authors: Ouzizi A. , Abdoun F. , Azrar L.
Published: August 2019

The present paper investigates the dynamic response of beams resting on fractional viscoelastic foundation subjected to a moving load with variable speeds. The Galerkin with finite difference methods are used to deal with the governing equation of motion. The effect of various parameters, like fractional order derivative, foundation stiffness and damping, speed of moving load on the response of the beam are investigated and discussed.
The experimental validation of a numerical model for the receptance prediction
Authors: Zougari A. , MartÍnez J.
Published: August 2019

The traditional ballasted track with wooden sleepers covers today most railway lines constructions, including the tracks of tram and metro or the industrial railway branching. In this work, we present an experimental methodology to validate a numerical model based on finite element method, the model was previously well defined using the ANSYS Parametric Design Language (APDL) and adapted to represent a classical ballasted track. The obtained result of the analysis is expressed as a frequency response of the track and it is compared to the experimental result from measurements made on the metropolitan classical railway track of Barcelona.
Development of a innovative solution for energy recovery from the flow exhaust gas on bench test facility of turbofan aircraft engine through the use of innovative design methods: Definition of the process and the operating environment
Authors: Rahoui Amine , Aalaoui Zinab
Published: August 2019

Civil aviation is driven nowadays by exceptional growth in the number of passengers. It should double or even triple by 2050 and thus, all industrials also plan to double the number of device delivery by mid-century. Responsible for about 2% of carbon dioxide on the planet, they must now deal with the environmental issues facing the sector.

At this moment in the world, several lines of research focus on increasing the efficiency of aircraft engines, development of new engines, efficient technologies, sustainable sources of alternative fuels and improved management air traffic on the ground and in flight [1].

The present work deals with a research focused on the engine test when passing in review in repair facilities. This operation which consist in making engine running while the cycles to test its performance in a test bench are studied to define a technological solution to reduce CO2 carbon footprint of the aircraft engine in this phase of the cycle of life. The idea is to produce electrical energy during these tests. To achieve this, we will highlight the case of a type bench facility for a specific airplane engines. As a result high-performance analysis tools are implemented to define the most suitable technological solution that ensures maximum efficiency, meets the functional and regulatory requirements taking into account the force of integration with the existing and cost optimization.

In this paper we present the summary of the working definition of the research process for the final term set in the operating environment integration relevance that provides bench test and level of innovation that provides the methods selected.
Numerical study of the effect of concrete cover and the friction of steel concrete interface
Authors: Zenasni Z. , Atlati S. , Haterbouch M. , Hannawi K. , Agbodgan W.P. , Nasri K. , Addou R. , Zenasni M.
Published: August 2019

The work presented in this paper resume a numerical analysis of the concrete cover effect, on the resistance of the steel-concrete interface. The effect of friction on the interface behavior is also included. For this, a brief description of the experimental steps generally used for the characterization of the steel-concrete interface is presented. Also, the CDP model, Concrete Damage Plasticity, is illustrated. The results of the numerical simulation using the Abaqus code are presented with different diameters of coatings with and without friction.
Simulation of compressible and incompressible flows in the presence of shocks
Authors: Benakrach H. , Taha-Janan M. , Es-Sadek M.Z.
Published: August 2019

The purpose of the present work is to use a finite volume method for solving Euler equations in the presence of shocks and discontinuities, with a generalized equation of state. This last choice allows to treat both compressible and incompressible fluids. The first results of the work are presented. They consist in simulating two-dimensional single-specie flows in the presence of shocks.

The results obtained are compared with the analytical results considered as benchmarks in the domain.
Jeffery-Hamel slip flow in a convergent microchannel with uniform wall temperature and streamwise heat conduction
Authors: Niagui Mohammed , Haddout Youssef , Oubarra Abdelaziz , Lahjomri Jawad
Published: August 2019

This work is devoted to the determination of the analytical solution of the problem of the laminar forced convection of the Jeffery-Hamel slip flow through a convergent microchannel. The analytical solution is obtained by using a self-adjoint formalism of the functional analysis. The solution represents an extension of the solution obtained in the conventional continuum flow by considering the boundaries slip conditions at the wall and the streamwise heat conduction. This extension has been done by using a new matrix operator of three dimensions in the Hilbert space. The results show that the thermal characteristics are strongly influenced by the Reynolds, Prandtl and Knudsen numbers, the aperture angle of the channel and the streamwise heat conduction.
Flow behavior analysis of confined fluid in a flexible tube: application of asymptotic approach
Authors: Mehdari A. , Agouzoul M. , Hasnaoui M.
Published: August 2019

In this paper, we asymptotically investigate a confined fluid flow in a flexible tube with a variable section. The fluid is considered to be newtonian, incompressible and it elapses in elastic and isotropic shell. This study provides a review of recent analysing the effects of the elastic wall tube properties over the fluid behaviour. The unsteady fluid flow will be analysed following the singular perturbations theory according to a large Reynolds number and a small aspect radio. The wall is assumed to be a thin shell that generate a small axisymmetric vibration. This model is mathematically developed by using the thin shell linear theory that is governed by a geodesic curvature parameter.
Principal accomplishments in the scientific theory of gearing
Authors: Radzevich Stephen
Published: August 2019

An in-depth analysis of the accomplishments in the theory of gearing has been undertaken by the author. The main results of the performed analysis are outlined in the paper in a chronological order. Two periods of time are proposed to be considered: pre-Eulerian and post-Eulerian time of the evolution of the gear art. No principal accomplishments in the theory of gearing were attained in the pre-Eulerian period of evolution of gearing. It is stated that scientific theory of gearing is originated from the publication by Leonhard Euler of two of his famous papers (1760). The main theorem of parallel-axes gearing, or, in other words, the “conjugate action law”, is loosely attributed to R. Willis (1841), which is not correct. Ch. Camus was the first (1733), who has carried out a research on this subject, however he failed to formulate this law of gearing correctly. In the final form the theorem was known to L. Euler and to F. Savaryr. Therefore, it is proposed to refer to the main theorem of parallel-axes gearing as to the “Camus-Euler-Savaryr theorem of gearing” (or just as to the “CES-theorem of gearing”, for simplicity). A huge mistake in the theory of gearing was committed by T. Olivier (1842). The effect of this mistake onto the evolution of the theory of gearing is discussed. Contributions by G. Grant (1887), and by V. Shishkovt (1948), that is, his well-known equation of contact, n·VΣ=0, are outlined. Introduced in around 2008, concept of the operating base pitch in a gear pair considered in detail. Latest accomplishments in the theory of gearing are summarized and briefly discussed in the paper. These accomplishments form the foundation of the self-consistent scientific theory of gearing (Radzevich, S.P., 2012, 2018). The scientific theory of gearing is not threatened with destruction, but only superstructure and development are extected (every scientific theory features this property).
Improvement of design parameters of planetary multipliers and reducers, using specialized author’s software for joined gears drives
Authors: Nenov Peter , Kaloyanov Bojidar , Danev Plamen
Published: August 2019

The present work discus two indicative cases from the practice, in which the final results significantly exceed those of the "base" multiplier and the „initial“ reducer. The constructions are promising for the development of electricity generation from tides, respectively - for the electric hoist industry. The first reconstruction includes detailed analysis and substantial changes of the entire product, focusing on important changes to its structural and technological parameters that will make it feasible. At the same time, in the both projects, using author 's specialized software, multi-variance design and parallel analysis of the results good solution very near to their optimal values was found. The additional goal of the authors is to share how this approach and tools, combined with successful machine-building design systems, can contribute to raising the level of all power gears drives.