bluuebunny/crossref_metadata_2025 huggingface dataset:
On detour index of cycloparaphenylene and polyphenylene molecular structures
Authors: Prabhu S. , Nisha Y. Sherlin , Arulperumjothi M. , Jeba D. Sagaya Rani , Manimozhi V.
Published: July 2021

Cycloparaphenylene is a particle that comprises a few benzene rings associated with covalent bonds in the para positions to frame a ring-like structure. Similarly, poly (para-phenylenes) are macromolecules that include benzenoid compounds straightforwardly joined to each other by C–C bonds. Because of their remarkable architectural highlights, these structures have fascinated attention from numerous vantage focuses. Descriptors are among the most fundamental segments of prescient quantitative structure-activity and property relationship (QSAR/QSPR) demonstrating examination. They encode chemical data of particles as quantitative numbers, which are utilized to create a mathematical correlation. The nature of a predictive model relies upon great demonstrating insights, yet additionally on the extraction of compound highlights. To a great extent, Molecular topology has exhibited its adequacy in portraying sub-atomic structures and anticipating their properties. It follows a two-dimensional methodology, just thinking about the interior plan, including molecules. Explicit subsets speak the design of every atom of topological descriptors. When all around picked, these descriptors give a unique method of describing an atomic system that can represent the most significant highlights of the molecular structure. Detour index is one such topological descriptor with much application in chemistry, especially in QSAR/QSPR studies. This article presents an exact analytical expression for the detour index of cycloparaphenylene and poly (para-phenylene).
Novel hypergravity treatment enhances root phenotype and positively influences physio-biochemical parameters in bread wheat (Triticum aestivum L.)
Authors: Swamy Basavalingayya K. , Hosamani Ravikumar , Sathasivam Malarvizhi , Chandrashekhar S. S. , Reddy Uday G. , Moger Narayan
Published: July 2021

Hypergravity—an evolutionarily novel environment has been exploited to comprehend the response of living organisms including plants in the context of extra-terrestrial applications. Recently, researchers have shown that hypergravity induces desired phenotypic variability in seedlings. In the present study, we tested the utility of hypergravity as a novel tool in inducing reliable phenotype/s for potential terrestrial crop improvement applications. To investigate, bread wheat seeds (UAS-375 genotype) were subjected to hypergravity treatment (10×g for 12, and 24 h), and evaluated for seedling vigor and plant growth parameters in both laboratory and greenhouse conditions. It was also attempted to elucidate the associated biochemical and hormonal changes at different stages of vegetative growth. Resultant data revealed that hypergravity treatment (10×g for 12 h) significantly enhanced root length, root volume, and root biomass in response to hypergravity. The robust seedling growth phenotype may be attributed to increased alpha-amylase and TDH enzyme activities observed in seeds treated with hypergravity. Elevated total chlorophyll content and Rubisco (55 kDa) protein expression across different stages of vegetative growth in response to hypergravity may impart physiological benefits to wheat growth. Further, hypergravity elicited robust endogenous phytohormones dynamics in root signifying altered phenotype/s. Collectively, this study for the first time describes the utility of hypergravity as a novel tool in inducing reliable root phenotype that could be potentially exploited for improving wheat varieties for better water usage management.
Cognitive map formation through haptic and visual exploration of tactile city-like maps
Authors: Ottink Loes , Hoogendonk Marit , Doeller Christian F. , Van der Geest Thea M. , Van Wezel Richard J. A.
Published: July 2021

In this study, we compared cognitive map formation of small-scale models of city-like environments presented in visual or tactile/haptic modalities. Previous research often addresses only a limited amount of cognitive map aspects. We wanted to combine several of these aspects to elucidate a more complete view. Therefore, we assessed different types of spatial information, and consider egocentric as well as allocentric perspectives. Furthermore, we compared haptic map learning with visual map learning. In total 18 sighted participants (9 in a haptic condition, 9 visuo-haptic) learned three tactile maps of city-like environments. The maps differed in complexity, and had five marked locations associated with unique items. Participants estimated distances between item pairs, rebuilt the map, recalled locations, and navigated two routes, after learning each map. All participants overall performed well on the spatial tasks. Interestingly, only on the complex maps, participants performed worse in the haptic condition than the visuo-haptic, suggesting no distinct advantage of vision on the simple map. These results support ideas of modality-independent representations of space. Although it is less clear on the more complex maps, our findings indicate that participants using only haptic or a combination of haptic and visual information both form a quite accurate cognitive map of a simple tactile city-like map.
Effect of lighting illuminance and colour temperature on mental workload in an office setting
Authors: Bao Jiayi , Song Xinbo , Li Yan , Bai Yinjie , Zhou Qianxiang
Published: July 2021

The mental workload of subjects was tested under different lighting conditions, with colour temperatures ranging from 3000 to 6500 K and illuminance ranging from 300 to 1000 lx. We used both psychological and physiological responses for evaluation. The former was based on NASA Task Load Index (NASA-TLX, NASA), and the latter was based on the electroencephalogram (EEG) P3b analysis of event-related potentials using the “oddball” paradigm experimental task. The results show that as illuminance increases, and the response time becomes longer with a colour temperature of 3000 K (P < 0.01). However, when the colour temperature is set at 6500 K, the response time becomes shorter as the illuminance increases (P < 0.01). P3b amplitudes were significantly affected by colour temperature (P = 0.009) and illuminance (P = 0.038) levels. The highest amplitudes occurred at 3000 K and 750 lx, which is consistent with the trend shown by the subjective scale. The data analysis of error rates is not significant. These results suggest that an office environment with a colour temperature of 3000 K and illumination of 750 lx, which exerts the lowest mental workload, is the most suitable for working. However, the interaction between colour temperature and illuminance in affecting the mental workload of participants is not clear. This work provides more appropriate lighting choices with colour temperature and illuminance to reduce people’s mental workload in office settings.
Catalytical feature of optical nanoprobes of boron nitride quantum dots in the presence of Cu2+ for the determination of dopamine
Authors: Fan Xiushuang , Qiu Jinpeng , Peng Chao , Ren Jiangtao , Xing Huanhuan , Bi Chuyao , Yin Jianyuan , Li Jing
Published: July 2021

Boron nitride quantum dots (BNQDs) can catalyze polymerization of dopamine and formation of polydopamine in the co-existence of Cu2+, resulting in fluorescence quenching of BNQDs, which provides the new strategy for dopamine analysis.
Biocompatible perovskite quantum dots with superior water resistance enable long-term monitoring of the H2S level in vivo
Authors: Luo Fang , Li Shiqing , Cui Limei , Zu Yexing , Chen Yiting , Huang Da , Weng Zuquan , Lin Zhenyu
Published: July 2021

The water-resistant and biocompatible perovskite quantum dots formed by coating with polyethylene glycol-polycaprolactone are capable of long-term and real-time monitoring of the H2S level in vitro and in vivo.
Adsorption of ethylenediamine on Cu surfaces: attributes of a successful capping molecule using first-principles calculations
Authors: Chen Zihao , Fichthorn Kristen A.
Published: July 2021

Ethylenediamine packs less densely in adsorption on Cu(111) than on Cu(100), enabling faster water transport to Cu(100) than Cu(111), This promotes selective Cu(100) oxidation and the growth of penta-twinned Cu nanowires, consistent with experiment.
Boosting the photothermal performance of vacancy-rich MoSe2−x nanoflowers for photoacoustic imaging guided tumor chemo-photothermal therapy
Authors: Gao Fei , Miao Yuqing , Ma Huijun , Zhang Tingbin , Fan Haiming , Zhao Lingyun
Published: July 2021

The vacancy-rich MoSe2−x nanoflowers with activity target molecular 2-deoxy-d-glucose (2-DG) was synthesized, and it could be used as a novel phototheranostics nanoagent in the photoacoustic imaging guided chemo-photothermal synergistic therapy.
Temperature-programmed desorption of large molecules: influence of thin film structure and origin of intermolecular repulsion
Authors: Dombrowski Pierre-Martin , Kachel Stefan R. , Neuhaus Leonard , Gottfried J. Michael , Witte Gregor
Published: July 2021

The combination of temperature-programmed desorption with Kelvin probe and STM data allows to quantify and characterize intermolecular interactions in pentacene monolayers adsorbed on gold.
Electrochemical bromofunctionalization of alkenes in a flow reactor
Authors: Seitz Jakob , Wirth Thomas
Published: July 2021

Electrochemical flow functionalization of alkenes is providing fast and easy access to dibromides or bromohydrins.
A transparent cyclo-linear polyphenylsiloxane elastomer integrating high refractive index, thermal stability and flexibility
Authors: Fan Xianpeng , Cao Xinyu , Shang Xinxin , Zhang Xianglan , Huang Cheng , Zhang Jingnan , Zheng Kun , Ma Yongmei
Published: July 2021

A cyclo-linear structured transparent polyphenylsiloxane elastomer combining high refractive index, high thermal stability and superior flexibility was prepared by a one-pot hydrosilylation reaction.
Spontaneous and induced chiral symmetry breaking of stereolabile pillar[5]arene derivatives upon crystallisation
Authors: Wang Haiying , Yang Weiwei , Baldridge Kim K. , Zhan Cai-Hong , Thikekar Tushar Ulhas , Sue Andrew C.-H.
Published: July 2021

Stereolabile pillar[5]arene derivatives, which are dynamic racemic mixtures in solution on account of their low inversion barriers, were employed as platforms to study chiral symmetry breaking during crystallisation.
An umpolung-enabled copper-catalysed regioselective hydroamination approach to α-amino acids
Authors: Nishino Soshi , Miura Masahiro , Hirano Koji
Published: July 2021

A copper-catalysed regio- and enantioselective hydroamination of acrylates has been developed to afford the corresponding optically active unnatural α-amino acids.
Boundary layer description of directional polymer crystallisation
Authors: Adhikari Sabin , Krauskopf Alejandro A. , Kumar Sanat K. , Thampi Sumesh P. , Durning Christopher J.
Published: July 2021

We develop a boundary layer solution for directional polymer crystallisation providing a clearer understanding of nearly fifty years old polymer zone annealing experiments.
Self-Reported Reasons for the Non-Use of Hearing Aids Among Hispanic Adults With Hearing Loss
Authors: Desjardins Jamie L. , Sotelo Loren R.
Published: July 2021

Purpose

To examine the self-reported reasons for the non-use of hearing aids among Mexican–American Hispanic adults who have hearing loss.

Method

A total of 122 Hispanic adults with hearing loss, who did not currently or previously use a hearing aid, participated in this study. Participants completed a comprehensive hearing health questionnaire and the Hearing Handicap Inventory Screening Questionnaire to examine the possible reasons for the non-use of hearing aids.

Results

Self-reported hearing loss, hearing handicap score, and health insurance status were the best predictors of an individual's willingness to use hearing aids to treat their hearing loss. The primary reasons cited for the non-use of hearing aids among Hispanics with hearing loss was the belief that their hearing impairment was not severe enough to warrant using a hearing aid and that hearing aids were unaffordable.

Conclusions

Greater public health education regarding the deleterious effects of untreated hearing loss and the positive impact of amplification on cognitive, social, and psychological health may be warranted to improve the usage rates of hearing aids in Hispanic adults.
Effect of Oral Motor Intervention on Oral Feeding in Preterm Infants: A Systematic Review and Meta-Analysis
Authors: Chen Danna , Yang Zhen , Chen Chujie , Wang Pu
Published: July 2021

Objective

This review article aimed to explore the effect of oral motor intervention on oral feeding in preterm infants through a meta-analysis.

Method

Eligible studies were retrieved from four databases (PubMed, Embase, Cochrane Library, and Web of Science) up to July 2020 and screened based on established selection criteria. Thereafter, relevant data were extracted and heterogeneity tests were conducted to select appropriate effect models according to the chi-square test andI2statistics. Assessment of risk of bias was performed among the included studies. Finally, a meta-analysis was carried out to evaluate the effect of oral motor intervention in preterm infants according to four clinical indicators: transition time for oral feeding, length of hospital stay, feeding efficiency, and weight gain.

Results

Eighteen randomized controlled trials with 848 participants were selected to evaluate the effect of oral motor intervention on preterm infants. The meta-analysis results revealed that oral motor intervention could effectively reduce the transition time to full oral feeds and the length of hospital stay as well as increase feeding efficiency and weight gain.

Conclusions

Oral motor intervention was an effective way to improve oral feeding in preterm infants. It is worthy to be used widely in hospitals to improve the clinical outcomes of preterm infants and reduce the economic burdens of families and society. Future studies should seek to identify detailed intervention processes and intervention durations for clinical application.
An adaptive sliding‐mode resilient control strategy in smart grid under mixed attacks
Authors: Li Jian , Yang De‐Fu , Gao Yan‐Chao , Huang Xin
Published: July 2021

This paper is concerned with security problems for cyber‐physical systems (CPSs) under dynamic load altering attacks (DLAA) and false data injection attacks (FDIA). The smart grid, as a typical CPS system, is taken as an example in this paper. Since the communication channel is vulnerable to FDIA and DLAA, the stability of the smart grid may be influenced. For enhancing resilience and stability of smart grids, first of all, the power system model including both DLAA and FDIA is introduced. Second, an adaptive sliding mode controller is proposed. The controller can ensure the reliable operation of the power system in the case of unknown attack information by using the adaptive mechanism online estimating the upper bound of attack signal to automatically eliminate the effect of mixed attacks. Finally, a power system with three generators and six buses is taken as an illustrative example, and simulation and experiment results obtained by using MATLAB and Hardware‐in‐time platform built by Sartsim verify the effectiveness of the proposed resilient defense strategy.
A formula for the admittance of laterally excited bulk wave resonators (XBARs)
Authors: Plessky Victor , Küçük Seniz , Yandrapalli Soumya , Villanueva Luis Guillermo
Published: July 2021

The recently invented laterally excited bulk wave resonators (XBARs) demonstrate outstanding parameters suitable for the design of low loss filters for the fifth generation of mobile phones. The operation of XBARs can be interpreted as an excitation of anti‐symmetric Lamb mode A1 by the interdigital transducer. However, it can also be seen as the generation of fundamental plate resonances in a set of parallelly connected quasi‐independent resonators, excited by a lateral electric field created by narrow electrodes with alternating polarity. By exploiting this latter interpretation, we propose a formula for the admittance of multi‐layered membranes, including the main piezoelectric layer of suitable orientation and different additional dielectric layers on both sides of the membranes. The structure can be asymmetric and the excitation of all shear wave thickness resonances, not only with odd numbers, is described. The formula can be used for the one‐dimensional modelling and optimisation of XBARs and the estimation of the resonance frequency dependence on the deposited trimming thin layers.
Exploiting texture characteristics and spatial correlations for robustness metric of data hiding with noisy transmission
Authors: Chen Yanli , Wang Hongxia , Wu Hanzhou , Zhou Yonghui , Zhou Limengnan , Chen Yi
Published: July 2021

Data hiding aims to embed a secret message into a digital object such as image by slightly modifying the object content without arousing noticeable artefacts. The resultant object containing hidden information will be sent to a desired receiver via some insecure channels, e.g. images transmitted through noisy channel, social networks are vulnerable to unknown pollution or compression by a third party, which may lead the transmitted objects to be attacked such that the reconstructed message has a significant error rate. It therefore requires us to use robust embedding strategies for data hiding to realise reliable message retrieval. To this end, in this paper, a metric model to estimate the robustness of data hiding for noisy transmission based on the statistical characteristics of cover and embedding operation is presented, the former is mainly reflected by spatial frequency and texture feature, and the latter embedding operation is mainly reflected by embedding modification. The goal is to ensure that both statistical characteristics and embedding operation can be used to maximise the embedding robustness. To the best knowledge, it is the first time to estimate robustness before data hiding by a special metric model. Experimental results show that, by combining the proposed metric model in three classical data hiding methods, i.e. BPS, DE and QIM, the robustness can be significantly improved, which demonstrates its superiority and applicability.
Curiouser and curiouser: the peculiar chemical composition of the Li- and Na-rich star in ω Centauri
Authors: Mucciarelli A. , Monaco L. , Bonifacio P. , Salaris M. , Saviane I. , Lanzoni B. , Momany Y. , Lo Curto G.
Published: July 2021

We present a multi-instrument spectroscopic analysis of the unique Li- and Na-rich giant star #25664 in ω Centauri, using spectra acquired with FLAMES-GIRAFFE, X-shooter, UVES, and HARPS. Li and Na abundances have been derived from the UVES spectrum using transitions weakly sensitive to non-local thermodynamic equilibrium and assumed isotopic ratios. This new analysis confirms the surprising Li and Na abundances of this star (A(Li)NLTE = +2.71 ± 0.07 dex, [Na/Fe]NLTE = +1.00 ± 0.05 dex). Additionally, we provide new pieces of evidence for its chemical characterisation. The 12C∕13C isotopic ratio (15 ± 2) shows that this star has not yet undergone the extra-mixing episode usually associated with the red giant branch bump. Therefore, we can rule out the scenario of efficient deep extra mixing during the red giant branch phase envisaged to explain the high Li and Na abundances. Also, the star exhibits high abundances of both C and N ([C/Fe] = +0.45 ± 0.16 dex and [N/Fe] = +0.99 ± 0.20 dex), which is not compatible with the typical C-N anti-correlation observed in globular cluster stars. We found evidence of a radial velocity variability in #25664, suggesting that the star could be part of a binary system, likely having accreted material from a more massive companion when the latter was evolving in the asymptotic giant branch (AGB) phase. Viable candidates for the donor star are AGB stars with 3–4 M⊙ and super-AGB stars (~7–8 M⊙), both of which are able to produce Li- and Na-rich material. Alternatively, the star could have formed from the pure ejecta of a super-AGB star before the dilution with primordial gas occurred.
Can La Redonda lagoon (Cuba) be a suitable habitat for largemouth bass (Micopterus salmoides, Lacepède) recovery?
Authors: González-De Zayas Roberto , Merino-Ibarra Martín , Lestayo González Julio A. , Castillo-Sandoval Fermín S. , Peraza-Escarrá Rosely
Published: July 2021

For decades, La Redonda lagoon was an excellent location for fishing the largemouth bass (Micopterus salmoides, Lacepède) in Cuba. There are indications that the species disappeared from the lagoon in 2009. Three water surveys were carried out in 2013 and 2014. Physicochemical parameters, including nutrients, were measured in all surveys. Chlorophyllaand water transparency were only measured in November 2013. Results showed that this lagoon is a fresh to brackish water system, with common salinization episodes. There were some hypoxic conditions, but mean dissolved oxygen value was above 5.0 ± 2.8 mg L−1for the entire survey period. The trophic state was evaluated as oligotrophic and Nitrogen and Phosphorus were limiting in most of the survey sites. The Habitat Suitability Index model (HSI) for largemouth bass had a mean value of 0.63 ± 0.02 (moderate degree of suitability). All results showed that bass recovery could be possible in La Redonda lagoon, but management criteria are necessary. The largemouth bass recovery could help to increase visitations of American anglers to this place and a portion of the revenue could be used to conduct environmental monitoring and studies of the largemouth bass ecology in Cuba.
A single-consignor multi-consignee multi-item model with permissible payment delay, delayed shipment and variable lead time under consignment stock policy
Authors: Karthick B. , Uthayakumar R.
Published: July 2021

This article proposes a two-level fuzzy supply chain inventory model, in which a single consignor delivers multiple items to the multiple consignees with the consignment stock agreement. The lead time is incorporated into the model and is considered a variable for obtaining optimal replenishment decisions. In addition, crashing cost is employed to reduce the lead time duration. This article investigates four different cases under controllable lead time to analyze the best strategy, focusing on two delays such as delay-in-payments and delay-in-shipment. In all four cases, all associated inventory costs are treated as a trapezoidal fuzzy number, and a signed distance method is employed to defuzzify the fuzzy inventory cost. An efficient optimization technique is adopted to find the optimal solution for the supply chain. Four numerical experiments are conducted to illustrate the four cases. Any one of these experimental results will provide the best solution for the ideal performance of the business under controllable lead time in the consignment stock policy. Finally, the managerial insights, conclusion and future direction of this model are provided.
‘Writing’ small states: contextualizing the construct in the Arab Gulf
Authors: Sadiki Larbi , Saleh Layla
Published: July 2021

How do IR scholars ‘write’ the Arab Gulf? In attempting to address this question, the focus is twofold: first, the ‘small state’ as a construct and second, its application to the study of Gulf small states. The article tries to grapple with issues inherent in such an enterprise by providing a critical assessment of recent scholarship on the topic, with special reference to Qatar and the UAE. The problematic comes to the fore in a context of these two countries’ increasing regional and international visibility, as well as what seems to be renewed scholarly interest in small states, more generally. Specifically, this analysis primarily seeks to relativize the small state within the Arab Gulf sub-region, drawing attention to ontological and epistemological issues. In so doing, the article offers some heuristics for the writing of small states in the Arab Gulf. One suggestion put forward in the article is more scrutiny of the regional context; what is called here the ‘hydrocarbon semi-periphery’; and misgivings (conceptual and empirical) concerning, respectively, the treatment of ‘soft power,’ mediation, and intervention. One parting idea to derive from this line of inquiry is its cautionary note against inflating the utility or the explanatory power of a catch-all ‘small state’ construct when it comes to non-Western settings.
Challenges and applications of wearable brain-computer interface technologies
Authors: Bandari Anashe
Published: July 2021

By enabling direct communication between the brain and external devices, neurotechnologies will eventually be integrated into nearly every aspect of everyday life.
A large enhancement of ionic conductivity in SrCoO2.5 controlled by isostructural phase transition and negative linear compressibility
Authors: Wang Bihan , Li Nana , Zhao Yongsheng , Liu Xuqiang , Li Mingtao , Zhang Qian , Dong Haini , He Yu , Zhang Dongzhou , Wang Yonggang , Liu Gang , Long Youwen , Yang Wenge
Published: July 2021

The exploration of next-generation materials and the underlying mechanisms for high ionic conductivity have been the mainstay of the study in the solid state ionic field, but with limited success. Here, we performed closely integrated in situ high-pressure structural and electronic characterizations on SrCoO2.5, a typical material for solid fuel cell application. We discovered that the activation energy for ionic transport decreased by approximately 47% at 13.6 GPa upon compression, demonstrating a large enhancement of conductivity. Such a desired functional behavior is strongly interlinked with the pressure-driven isostructural phase transition at which negative linear compressibility occurs along c-lattice, weakening the interaction between Co and O atoms and then enhancing the ionic diffusion. Our results provide fundamental insight of the solid ionic mechanism and materials-by-design for future high-performance oxides.
Sub-
μ
m features patterned with laser interference lithography for the epitaxial lateral overgrowth of α-Ga2O3 via mist chemical vapor deposition
Authors: Dang G. T. , Yasuoka T. , Kawaharamura T.
Published: July 2021

The low growth rate of mist chemical vapor deposition normally requires a long growth time to achieve coalescence in the epitaxial lateral overgrowth of α-Ga2O3 thin films on sapphire substrates. To address this issue, sub-μm features were patterned using laser interference lithography. Periodical stripes with a ∼590-nm pitch allowed the overgrowth of crack-free, void-free, and continuous thin films, while typical growth conditions using a low carrier gas flow rate and a low Ga precursor concentration were maintained. Coalescence was achieved even with a short growth time of <30 min and a low film thickness of <500 nm. Transmittance and x-ray diffraction spectra show that the film was predominantly in α-phase. Transmission electron microscopy (TEM) images reveal cup-top-like α-Ga2O3 regions of low dislocation density on the SiOx mask. Selected area electron diffraction and high-resolution TEM analyses confirm that an α-Ga2O3 layer was formed even on the top of the SiOx mask. Interestingly, the dislocations formed on the window areas did not bend toward the center of the masks; rather, a dislocation bending outward from the center was observed. This suggests the occurrence of early coalescence and/or atomic rearrangement.
Generation and detection of 50 GHz surface acoustic waves by extreme ultraviolet pulses
Authors: Maznev A. A. , Mincigrucci R. , Bencivenga F. , Unikandanunni V. , Capotondi F. , Chen G. , Ding Z. , Duncan R. A. , Foglia L. , Izzo M. G. , Masciovecchio C. , Martinelli A. , Monaco G. , Pedersoli E. , Bonetti S. , Nelson K. A.
Published: July 2021

We use femtosecond extreme ultraviolet pulses derived from a free electron laser to excite and probe surface acoustic waves (SAWs) on the (001) surface of single crystal SrTiO3. SAWs are generated by a pair of 39.9 nm pulses crossed at the sample with the crossing angle defining the SAW wavelength at 84 nm. Detection of SAWs is performed via diffraction of a time-delayed 13.3 nm probe pulse by SAW-induced surface ripples. Despite the low reflectivity of the sample in the extreme ultraviolet range, the reflection mode detection is found to be efficient because of an increase in the diffraction efficiency for shorter wavelengths. We describe a methodology for extracting the SAW attenuation in the presence of a thermal grating, which is based on measuring the decay of oscillations at twice the SAW frequency. The proposed approach can be used to study ultrahigh frequency SAWs in a broad range of materials and will bridge the wave vector gap in surface phonon spectroscopy between Brillouin scattering and He atom scattering.
The Synthesis, Structural Characterisation, and Chemoselective Manipulation of Certain Functionalised Cyclic Sulfates Derived from Chiral, Non-Racemic, and Polysubstituted Bicyclo[2.2.2]octane-2,3-diols
Authors: Banwell Martin G. , Crisp Antony L. , Lee BoRa , Lan Ping , Bollard Hannah E. , Ward Jas S. , Willis Anthony C.
Published: July 2021

Certain cyclic sulfates (e.g. 23) together with various of their precursor sulfites (e.g. 21 and 22) have been prepared from the corresponding chiral, non-racemic bicyclo[2.2.2]octane-2,3-diols (e.g. 20). Such diols are obtained by engaging the corresponding enzymatically derived and enantiomerically enriched or homochiral cis-1,2-dihydrocatechol (e.g. 10) or certain derivatives in either inter- or intra-molecular Diels–Alder cycloaddition reactions. Other functionalities present within the title compounds can be chemoselectively manipulated without adversely affecting the associated sulfate residues.
The interplay of proficiency and study abroad experience on the prosody of L2 speech acts
Authors: Kang Okim , Kermad Alyssa , Taguchi Naoko
Published: July 2021

AdoptingBrazil’s (1997)prosodic framework, this study examined whether proficiency and study abroad experience impact second language (L2) English learners’ spoken production of speech acts. Twenty-four native English speakers and 64 Japanese learners of L2 English participated in the study. The L2 learner group was divided into three sub-groups: (1) high proficiency learners with study abroad (SA) experience (2) low proficiency learners with no SA experience, and (3) high proficiency learners without SA experience. Participants completed an oral discourse completion task that assessed their ability to produce two speech acts (requests and opinions) in high- and low-imposition situations. Prosodic features including intonation, pitch range, and sentence prominence were analyzed via PRAAT. The findings revealed a complex interplay between proficiency and SA experience on pragma-prosodic production. Implications suggest that SA may have the added benefit of providing the backdrop for authentic contextual functions of prosody in high- and low- imposition situations.
Parameter setting and acceleration
Authors: Scalise Elena , Stahnke Johanna , Müller Natascha
Published: July 2021

The present contribution analyzes the acquisition of subjects in French based on a longitudinal case study of a trilingual child aged 2;8–3;2 who acquired French, Italian and Spanish simultaneously. The three languages vary with respect to the null-subject property; French is traditionally characterized as a non-null-subject language, while Italian and Spanish are prototypical null-subject languages. Argument subject omissions in French are ungrammatical but frequently observed in monolingual children in early acquisitional phases, as are ungrammatical postverbal subjects which cluster with null-subjects. Bilingual children acquiring French produce fewer subject omissions and postverbal subjects. The present study also finds an acceleration effect in the trilingual child. The results are interpreted in light of a parameter setting which accounts for different verb classes at different locations with which the null-subjects occur, giving rise to ‘categorial CS’ or ‘congruent categorialization.’
Analyzing variability in L2 ultimate attainment
Authors: Birdsong David
Published: July 2021

Ultimate attainment is typically more heterogeneous among second-language (L2) learners than among native speakers (e.g. Bley-Vroman, 1990). The present study offers a suite of simple analytical procedures aimed at exploring types and loci of variability in L2 attainment vis-à-vis those in the corresponding first language (L1), with special attention to certain learner-external factors that might condition such variabilities. To demonstrate the methods and their potential, we apply these procedures to learner and native acceptability judgment data published in Birdsong (1992). Under means analyses of item ratings and coefficients of variation (CV), a group of adult Anglophone learners of L2 French (ENS) are found to resemble native French controls (FNS). In contrast, under correlational analyses of ratings and CVs, ENS resemble FNS on grammatical items, but diverge on ungrammatical items. Correlational and means analyses of both CV and acceptability ratings reveal that ENS-FNS convergence is not predictable from the degree of FNS ratings variability, contra DeKeyser (2012). For both groups, we observe an interaction between FNS ratings variability and the grammatical status of items (ungrammatical vs. grammatical). Finally, for neither group do we find a relationship between the order of item presentation and ratings severity or CVs. We present our perspectives as a road map for future analyses of variabilities inherent in language learning outcomes.
Effects of proficiency and collaborative work on child EFL individual dictogloss writing
Authors: Calzada Asier , García Mayo María del Pilar
Published: July 2021

Collaborative writing has been traditionally studied in terms of language-related episodes (LREs), which have been
shown to be influenced by learner proficiency. Yet, the impact of collaboration on the written product has received less
attention, especially regarding child EFL learners. Our study analyzes the individual reconstructions produced by 30
Spanish-Basque EFL children (aged 11–12) before and after (T1 and T3) they completed a collaborative dictogloss (T2). From the
analysis of their LREs at T2, we predicted that certain areas (grammar and mechanics) could reflect more changes at T3 than
others. Moreover, we wanted to determine whether those changes were moderated by the learners’ and their partners’ proficiency at
T2: low (LP) or high (HP). Text-based and rubric measurements showed that only grammatical complexity improved in children’s
individual writing from T1 to T3. Regarding proficiency, LP children performed significantly worse than their HP counterparts at
T1 and T3 in most writing dimensions. Partner proficiency only influenced accuracy, and unexpectedly, working with an LP partner
did not appear to have a detrimental effect. Our findings stress the need to carry out longitudinal studies to further determine
the role of collaboration in L2 writing and knowledge development.
Pair dynamics and language-related episodes in child EFL task-based peer interaction
Authors: Pladevall-Ballester Elisabet
Published: July 2021

Previous research shows young learners are indeed able to interact in a foreign language (FL) and negotiate for meaning while also attending to form. One of the variables that has been least studied among young learners (YLs) in FL contexts is the kind of relationships established among the members of a dyad and how the nature of pair dynamics affects the learners’ ability to attend to language. The present study explores the pair dynamics and the frequency and types of language learning opportunities in the form of language-related episodes (LREs) that emerge during peer interaction in a spot-the-differences task completed by young learners in an English as a Foreign Language (EFL) context. We also examine the effects of age and pair dynamics on the production of these LREs. Results suggest that children interact mainly using collabo­rative patterns and can actually attend to language in episodes which are mainly meaning-focused and are resolved particularly in expert/novice dyads. Age has been found to significantly affect the production of LREs but pair dynamics seems to be less determinant. Findings corroborate the need for YLs to be given the chance to interact with their peers in class to foster learning opportunities.
Understandable public anger
Authors: Breeze Ruth
Published: July 2021

In the ten years from 2008 onwards the banking sector was constantly in the spotlight. Blame for the financial crisis and concern regarding controversial government bailouts were followed by public outrage about inflated bonuses, money laundering and false reporting. Over this period, banks deployed a range of legitimation strategies to salvage their reputation. This paper proposes a modified typology of legitimation strategies based on previous research (van Leeuwen and Wodak 1999; Vaara, Tienari and Laurila 2006), and examines how these are used by in the “letter to shareholders” published by the chairs of the five main UK-based banks over the ten years following the crisis. The strategies are analysed in terms of their object, target and interdiscursive features, and the particular persuasive roles of narrative and emotion are underlined.
Soliton solutions of the nonlinear Schrödinger equation with defect conditions
Authors: Gruner K T
Published: July 2021

Motivated by a recent development in the derivation of soliton solutions for initial-boundary value problems via the dressing method, we reconsider solutions to the nonlinear Schrödinger (NLS) equation on two half-lines connected via integrable defect conditions. The dressing method to construct soliton solutions is applied, while preserving the spectral boundary constraint with a time-dependent defect matrix. Moreover, N-soliton solutions are explicitly constructed and it is proven that the solitons are transmitted through the defect independently of one another.
Bifurcations of hidden orbits in discontinuous maps
Authors: Avrutin Viktor , Jeffrey Mike R
Published: July 2021

One-dimensional maps with discontinuities are known to exhibit bifurcations somewhat different to those of continuous maps. Freed from the constraints of continuity, and hence from the balance of stability that is maintained through fold, flip, and other standard bifurcations, the attractors of discontinuous maps can appear as if from nowhere, and change period or stability almost arbitrarily. But in fact this is misleading, and if one includes states inside the discontinuity in the map, highly unstable ‘hidden orbits’ are created that have iterates on the discontinuity. These populate the bifurcation diagrams of discontinuous maps with just the necessary unstable branches to make them resemble those of continuous maps, namely fold, flip, and other familiar bifurcations. Here we analyse such bifurcations in detail, focussing first on folds and flips, then on bifurcations characterised by creating infinities of orbits, chaotic repellers, and infinite accumulations of sub-bifurcations. We show the role that hidden orbits play, and how they capture the topological structures of continuous maps with steep branches. This suggests both that a more universal dynamical systems theory marrying continuous and discontinuous systems is possible, and shows how discontinuities can be used to approximate steep jumps in continuous systems without losing any of their topological structure.
Asymmetric multiscale multifractal analysis (AMMA) of heart rate variability
Authors: Kokosińska Dorota , Żebrowski Jan Jacek , Buchner Teodor , Baranowski Rafał , Orłowska-Baranowska Ewa
Published: July 2021

Objective. The physiological activity of the heart is controlled and modulated mostly by the parasympathetic and sympathetic nervous systems. Heart rate variability (HRV) analysis is therefore used to observe fluctuations that reflect changes in the activity in these two branches. Knowing that acceleration and deceleration patterns in heart rate fluctuations are asymmetrically distributed, the ability to analyze HRV asymmetry was introduced into MMA. Approach. The new method is called asymmetric multiscale multifractal analysis (AMMA) and the analysis involved six groups: 36 healthy persons, 103 cases with aortic valve stenosis, 36 with hypertrophic cardiomyopathy, 32 with atrial fibrillation, 59 patients with coronary artery disease (CAD) and 13 with congestive heart failure. Main results. Analyzing the results obtained for the 6 groups of patients based on the AMMA method, i.e. comparing the Hurst surfaces for heart rate decelerations and accelerations, it was noticed that these surfaces differ significantly. And the differences occur in most groups for large fluctuations (multifractal parameter q > 0). In addition, a similarity was found for all groups for the AMMA Hurst surface for decelerations to the MMA Hurst surface—heart rate decelerations (lengthening of the RR intervals) appears to be the main factor determining the shape of the complete Hurst surface and so the multifractal properties of HRV. The differences between the groups, especially for CAD, hypertrophic cardiomyopathy and aortic valve stenosis, are more visible if the Hurst surfaces are analyzed separately for accelerations and decelerations. Significance. The AMMA results presented here may provide additional input for HRV analysis and create a new paradigm for future medical screening. Note that the HRV analysis using MMA (without distinguishing accelerations from decelerations) gave satisfactory screening statistics in our previous studies.
Prolonged function and optimization of actomyosin motility for upscaled network-based biocomputation
Authors: Salhotra Aseem , Zhu Jingyuan , Surendiran Pradheebha , Meinecke Christoph Robert , Lyttleton Roman , Ušaj Marko , Lindberg Frida W , Norrby Marlene , Linke Heiner , Månsson Alf
Published: July 2021

Significant advancements have been made towards exploitation of naturally available molecular motors and their associated cytoskeletal filaments in nanotechnological applications. For instance, myosin motors and actin filaments from muscle have been used with the aims to establish new approaches in biosensing and network-based biocomputation. The basis for these developments is a version of the in vitro motility assay (IVMA) where surface-adsorbed myosin motors propel the actin filaments along suitably derivatized nano-scale channels on nanostructured chips. These chips are generally assembled into custom-made microfluidic flow cells. For effective applications, particularly in biocomputation, it is important to appreciably prolong function of the biological system. Here, we systematically investigated potentially critical factors necessary to achieve this, such as biocompatibility of different components of the flow cell, the degree of air exposure, assay solution composition and nanofabrication methods. After optimizing these factors we prolonged the function of actin and myosin in nanodevices for biocomputation from <20 min to >60 min. In addition, we demonstrated that further optimizations could increase motility run times to >20 h. Of great importance for the latter development was a switch of glucose oxidase in the chemical oxygen scavenger system (glucose oxidase–glucose–catalase) to pyranose oxidase, combined with the use of blocking actin (non-fluorescent filaments that block dead motors). To allow effective testing of these approaches we adapted commercially available microfluidic channel slides, for the first time demonstrating their usefulness in the IVMA. As part of our study, we also demonstrate that myosin motor fragments can be stored at −80 °C for more than 10 years before use for nanotechnological purposes. This extended shelf-life is important for the sustainability of network-based biocomputation.
Autocorrelation function for estimating static pressure fluctuation intensity in incompressible homogeneous turbulence under an intermediate Reynolds number
Authors: Suzuki Hiroki , Mochizuki Shinsuke , Hasegawa Yutaka
Published: July 2021

This study presents a simple form of an autocorrelation function that estimates the relative static pressure fluctuation intensity in the intermediate range of Reynolds numbers. When the Reynolds number is high or low, values of relative static pressure fluctuation intensity are each derived as simple values. This study attempts to estimate the intensity between high and low Reynolds numbers. Using the joint-normal approximation in the velocity field allows the relative static pressure fluctuation intensity to be given by integrating a function based on the autocorrelation function. For high and low Reynolds numbers, the autocorrelation function is given as exponential and Gaussian profiles, respectively. This study adds a higher-order term to these functions using Gram–Charlier and power series expansion. In the incompressible turbulence, a correlation function has to satisfy the continuity equation. Also, there is a defined relationship between the integral scale and the Taylor microscale derived from the autocorrelation function. This study investigates an autocorrelation function that satisfies these conditions. The value of one constant included in the present autocorrelation function shown in this study is derived as the appropriate value based on these conditions.
Emission of cosmic rays from Pulsar wind nebulae
Authors: Dai Xuer
Published: July 2021

The goal of the paper is to interpret AMS-02 positron data. Most of the positrons come from secondary production which can fit well the data below 10 GeV. However, above 10 GeV the positron flux detected is much higher than the predictions for the secondary production. This is called ‘positron excess’ whose origin remains unknown, and interpretations including supernova remnants, pulsar wind nebulae (PWNe) or dark matter have been considered. In this paper, we investigate if PWNe can explain this ‘positron excess’ and whether a single pulsar can contribute entirely to it. To do this, we select some powerful pulsars in the ATNF Pulsar Catalogue with specific age and distances from earth and calculate their positron flux. By using a minimization package in Python to adjust the spectral slope of the PWNe and the normalization of the secondaries, we find the best fit to AMS-02 data for each of those pulsars. We can see from the result that if we want to explain the ‘positron excess’ using a single pulsar, Geminga is the best solution in the ATNF Pulsar Catalogue. Moreover, we find that except for the powerful pulsar J0633+1746 (Geminga), B1742-30 and J1741-2054, most of the pulsars we selected need an efficiency much greater than 1 to fit the data. It means that for those pulsars, one pulsar’s energy is not powerful enough to explain the data entirely. Therefore, for pulsars that are not powerful enough, adding more pulsars together provides us with a possible way to interpret this ‘positron excess’ problem.
Numerical simulation of the exposed area of high-altitude electromagnetic pulse on the ground and its influencing factors
Authors: Li Ya , Wang Jianguo , Zuo Yinghong , Zhu Jinhui , Niu Shengli
Published: July 2021

In traditional High-Altitude Electromagnetic Pulse (HEMP) research, the line-of-sight area on the earth’s surface of the burst is approximately regarded as the exposed area of HEMP on the ground. However, the line-of-sight area is only affected by the height of burst, and cannot reflect the influence of yield and the distribution of peak HEMP fields on the ground. In this paper, the ground distance between ground zero and the southernmost point of peak HEMP field contour is defined as south radius for explosions in the northern hemisphere. The numerical simulation results of south radius of different peak HEMP field contours are given, and the impact of burst height and yield on south radius is analysed. It is concluded that when the yield is fixed, the south radius increases first and then decreases as the burst height increases. When the burst height is fixed, the south radius increases as the yield increases, but the rate of increase keeps decreasing.