bluuebunny/crossref_metadata_2025 huggingface dataset:
Discovery and characterization of the exoplanets WASP-148b and c
Authors: Hébrard G. , Díaz R. F. , Correia A. C. M. , Collier Cameron A. , Laskar J. , Pollacco D. , Almenara J.-M. , Anderson D. R. , Barros S. C. C. , Boisse I. , Bonomo A. S. , Bouchy F. , Boué G. , Boumis P. , Brown D. J. A. , Dalal S. , Deleuil M. , Demangeon O. D. S. , Doyle A. P. , Haswell C. A. , Hellier C. , Osborn H. , Kiefer F. , Kolb U. C. , Lam K. , Lecavelier des Étangs A. , Lopez T. , Martin-Lagarde M. , Maxted P. , McCormac J. , Nielsen L. D. , Pallé E. , Prieto-Arranz J. , Queloz D. , Santerne A. , Smalley B. , Turner O. , Udry S. , Verilhac D. , West R. , Wheatley P. J. , Wilson P. A.
Published: June 2020

We present the discovery and characterization of WASP-148, a new extrasolar system that includes at least two giant planets. The host star is a slowly rotating inactive late-G dwarf with a V = 12 magnitude. The planet WASP-148b is a hot Jupiter of 0.72 RJup and 0.29 MJup that transits its host with an orbital period of 8.80 days. We found the planetary candidate with the SuperWASP photometric survey, then characterized it with the SOPHIE spectrograph. Our radial velocity measurements subsequently revealed a second planet in the system, WASP-148c, with an orbital period of 34.5 days and a minimum mass of 0.40 MJup. No transits of this outer planet were detected. The orbits of both planets are eccentric and fall near the 4:1 mean-motion resonances. This configuration is stable on long timescales, but induces dynamical interactions so that the orbits differ slightly from purely Keplerian orbits. In particular, WASP-148b shows transit-timing variations of typically 15 min, making it the first interacting system with transit-timing variations that is detected on ground-based light curves. We establish that the mutual inclination of the orbital plane of the two planets cannot be higher than 35°, and the true mass of WASP-148c is below 0.60 MJup. We present photometric and spectroscopic observations of this system that cover a time span of ten years. We also provide their Keplerian and Newtonian analyses; these analyses should be significantly improved through future TESS observations.
External reconnection and resultant reconfiguration of overlying magnetic fields during sympathetic eruptions of two filaments
Authors: Hou Y. J. , Li T. , Song Z. P. , Zhang J.
Published: June 2020

Context. Sympathetic eruptions of two solar filaments have been studied for several decades, but the detailed physical process through which one erupting filament triggers another is still under debate.

Aims. Here we aim to investigate the physical nature of a sympathetic event involving successive eruptions of two filaments on 2015 November 15-16, which presented abundant sympathetic characteristics.

Methods. Combining data from the Solar Dynamics Observatory and other observatories as well as results of nonlinear force-free field (NLFFF) extrapolations, we study the evolution of observational features and magnetic topology during the sympathetic event.

Results. The two filaments (north F1 and south F2) were separated by a narrow region of negative polarity, and F1 first erupted, producing a two-ribbon flare. When the outward-spreading ribbon produced by F1 approached stable F2, a weak brightening was observed to the south of F2 and then spread northward, inward approaching F2. Behind this inward-spreading brightening, a dimming region characterized by a plasma density reduction of 30% was extending. NLFFF extrapolations with a time sequence reveal that fields above pre-eruption F1 and F2 constituted a quadrupolar magnetic system with a possible null point. Moreover, the null point kept moving toward F2 and descending within the following hours. We infer that the rising F1 pushed its overlying fields toward the fields above stable F2 and caused successive external reconnection between the overlying fields. From outside to inside (lower and lower in height), the fields above pre-eruption F2 were gradually involved in the reconnection, manifesting as the inward-spreading brightening and extending dimming on the south side of F2. Furthermore, the external reconnection could reconfigure the overlying fields of F2 by transporting magnetic flux from its west part to the east part, which is further verified by the subsequent partial eruption of F2.

Conclusions. We propose an integrated evidence chain to demonstrate the critical roles of external magnetic reconnection and the resultant reconfiguration of overlying fields on the sympathetic eruptions of two filaments.
A spectroscopic multiplicity survey of Galactic Wolf-Rayet stars
Authors: Dsilva K. , Shenar T. , Sana H. , Marchant P.
Published: June 2020

Context. It is now well established that the majority of massive stars reside in multiple systems. However, the effect of multiplicity is not sufficiently understood, resulting in a plethora of uncertainties about the end stages of massive-star evolution. In order to investigate these uncertainties, it is useful to study massive stars just before their demise. Classical Wolf-Rayet stars represent the final end stages of stars at the upper-mass end. The multiplicity fraction of these stars was reported to be ∼0.4 in the Galaxy but no correction for observational biases has been attempted.

Aims. The aim of this study is to conduct a homogeneous radial-velocity survey of a magnitude-limited (V ≤ 12) sample of Galactic Wolf-Rayet stars to derive their bias-corrected multiplicity properties. The present paper focuses on 12 northern Galactic carbon-rich (WC) Wolf-Rayet stars observable with the 1.2 m Mercator telescope on the island of La Palma.

Methods. We homogeneously measured relative radial velocities (RVs) for carbon-rich Wolf-Rayet stars using cross-correlation. Variations in the derived RVs were used to flag binary candidates. We investigated probable orbital configurations and provide a first correction of observational biases through Monte-Carlo simulations.

Results. Of the 12 northern Galactic WC stars in our sample, seven show peak-to-peak RV variations larger than 10 km s−1, which we adopt as our detection threshold. This results in an observed spectroscopic multiplicity fraction of 0.58 with a binomial error of 0.14. In our campaign, we find a clear lack of short-period (P < ∼100 d), indicating that a large number of Galactic WC binaries likely reside in long-period systems. Finally, our simulations show that at the 10% significance level, the intrinsic multiplicity fraction of the Galactic WC population is at least 0.72.
Aerodynamic control of a diffusion flame to optimize materials' transition in a rotary cement kiln
Authors: Nial Mohamed , Loukarfi Larbi , Naji Hassane
Published: June 2020

The aim of this work is to deepen the understanding of the aerodynamics of a diffusion flame in a rotary cement kiln. The kiln is a rotary with a cylindrical shaped, long and equipped with a burner, and it is the seat of a diffusion flame with an axisymmetric turbulent jet. The kiln has a capacity of 8,000 Nm3 to 13,000 Nm3 of natural gas and primary air at T = 25 °C which interacts with a secondary hot air volume at T = 800 °C. The aerodynamic modelling of the furnace is achieved using the turbulence model RNG k–ε, which is able to handle the turbulence and capture the vortex shedding process. The Ansys/Fluent code, based on the finite volume approach to solve the Reynolds averaged Navier-Stokes (RANS), was used in this study. The interactions between turbulence and diffusion flame were handled by the PDF (Probability Density Function) approach. The numerical simulations have been validated by experiments from the kiln considered. Based on the findings obtained, it is concluded that the recirculation zone seems of paramount importance when combustion is taken into account because the reverse flow improves the flame stability and affects the combustion efficiency. In addition, limiting the secondary air flow through the furnace is major to improve combustion and avoid disturbing the advancement of the material along the kiln.
Wegrauke, Sisymbrium officinale (L.) Scop.
Authors: Braun Sabine , Melzig Matthias F.
Published: June 2020

Sisymbrium officinale (L.) Scop., die Wegrauke, ist eine weltweit verbreitete Pflanze, die v. a. Glucosinolate wie Glucoputranjivin sowie Schleimstoffe und Flavonoide enthält. Eine phytochemische Besonderheit ist das Auftreten von Cardenolidglykosiden. Die Droge weist vielfältige pharmakologische Aktivitäten auf, zu der antibakterielle und antimutagene Effekte zählen. Ihre Anwendung als traditionelles Arzneimittel bei Reizungen im Rachenraum, wie Heiserkeit und bei trockenem Husten, wird durch eine HMPC-Monografie beschrieben.
Ernährungsbedingte Anämien im Vorschulalter
Authors: Wiederer Lisa , Rozwadowska Agnieszka , Duevel Melanie , Eber Stefan
Published: June 2020

Ernährungsbedingte Anämien (durch Eisen- oder Vitamin-B12-Mangel) sind im Kindesalter kein seltenes Problem. Oft liegt der Ursprung der Anämie in der mütterlichen Vitaminversorgung, insbesondere während der Schwangerschaft. Ein Eisenmangel sowie Vitamin-B12-Mangel sollten ausgeglichen werden, um irreversible Schäden wie Entwicklungsstörungen zu vermeiden. Dafür stehen orale sowie parenterale Wirkstoffe zur Verfügung.
OP nach Traverso-Longmire: die pyloruserhaltende Whipple-OP
Authors: Müller Michael , Meyer Detlef
Published: June 2020

Am Adenokarzinom des Pankreas erkranken in Deutschland circa 18 000 Menschen jährlich. Es ist inzwischen die vierthäufigste Krebstodesursache. Unsere Autoren stellen die Traverso-Longmire-OP vor. Da diese Variante ein geringeres Operationstrauma für den Patienten bedeutet, wird sie inzwischen der „klassischen“ OP nach Kausch-Whipple vorgezogen.
Kommunikation mit demenzerkrankten Patienten im OP
Authors: Ludwig Susanne
Published: June 2020

Wenn ein demenzerkrankter Patient in den OP kommt, fühlt er häufig Angst: die Umgebung ist befremdlich, die „vermummten“ Menschen bedrohlich und er versteht nicht, warum er überhaupt hier ist. Dann ist es wichtig, dass die OP-Pflegenden einfühlsam und wertschätzend mit ihm kommunizieren – verbal und nonverbal. Wie dies gelingt und welche Kommunikationshilfen es gibt, um die Angst des Patienten zu reduzieren, erläutert unsere Autorin.
Schröpftherapie am Pferd – Myofasziale Restriktionen lösen
Authors: Landskron Diana
Published: June 2020

Wird Gewebe durch ein Vakuum in eine Glasglocke gezogen, beginnen in den behandelten Arealen eine Vielzahl an biochemischen Prozessen. Zudem entsteht ein hoher mechanischer Reiz, welcher sich von den oberen in die tieferen Gewebeschichten fortsetzt. Dadurch werden dem Pferdetherapeuten neue interessante Behandlungsansätze geboten.
Medikamentös induzierte Schlafendoskopie
Authors: Hofauer Benedikt , Heiser Clemens , Kehm Vadim , Knopf Andreas , Offergeld Christian
Published: June 2020

Die medikamentös induzierte Schlafendoskopie (MISE) stellt ein Verfahren zur Beurteilung der oberen Atemwege unter Sedierung bei Patienten mit obstruktiver Schlafapnoe (OSA) dar und wurde erstmalig bereits im Jahr 1991 von Croft und Pringle beschrieben 1. Ungeklärt ist bisher, inwiefern die MISE mit dem natürlichen Schlaf vergleichbar ist. Eastwood und Kollegen beschrieben letztendlich eine Korrelation hinsichtlich der Kollapsneigung in Sedierung und während des natürlichen Schlafs. Damit zeigten die Kollegen, dass die MISE in der individualisierten Therapieberatung sinnvoll ist 2. In den vergangenen Jahren wurden Anstrengungen zur Standardisierung unternommen, um die Ergebnisse vergleichbarer und reproduzierbarer zu gestalten. Gerade mit Einführung und zunehmender Verbreitung der Stimulationstherapie des N. hypoglossus wird die MISE in den letzten Jahren vermehrt auch an Kliniken eingesetzt, die dieses diagnostische Verfahren bisher noch nicht durchführten. Dieser Beitrag soll die Durchführung einer MISE in Anlehnung an das entsprechende europäische Positionspapier vorstellen 3
4.
Kommunikation auf Distanz: Online-Meetings, Video-Chats und Telefonkonferenzen
Authors: Woll Corinne
Published: June 2020

Dieser Artikel ist Anfang April während der Corona-Pandemie entstanden – als für viele Mitmenschen die Devise lautete: Stay home! Wie lange die Kontaktsperre andauern wird, war zu diesem Zeitpunkt ungewiss. Was jedoch feststand: COVID-19 sorgte für viele von uns für rasante Veränderungen in der beruflichen und privaten Kommunikation. Unsere Autorin erläutert, wie Sie mit Messenger-Diensten, Video-Chats, Telefon und E-Mails – nicht nur in Krisenzeiten – den Kontakt zur Außen- und Arbeitswelt aufrechterhalten.
New Endophytic Fusarium spp. from Fraxinus excelsior Leaves in Slovakia
Authors: Ivanova Helena , Malinicova Lenka , Piknova Maria , Pristas Peter
Published: June 2020

Fraxinus excelsior is currently suffering from ash dieback disease caused by the fungus Hymenoscyphus fraxineus. Co-occurrence of large numbers of other fungi with endophytic as well as pathogenic lifestyles has been observed on F. excelsior. In this study, new endophytic Fusarium spp. isolate Fraxinus excelsior Fusarium from Slovak territory, associated with F. excelsior, was characterised. Using morphology-based approaches, the fungus was assigned to the genus Fusarium. The isolate formed thick-walled hyaline, fusiform, slightly curved macroconidia, produced from monophialides in sporodochia, pointed at the tip, mostly 3 – 5 septate, occasionally 6 septate, and 40 – 68 × 3.8 – 5.0 µm in size with basal pedicellate cells. For more accurate taxonomic affiliation, molecular sequence analyses of the internal transcribed spacer, translation elongation factor 1-alpha sequences, and partial β-tubulin gene were performed.
While the internal transcribed spacer sequence of the isolate showed the highest similarity to the Fraxinus oxysporum species, translation elongation factor 1-alpha and partial β-tubulin sequences were distantly related to the Fraxinus avenaceum species. Based on these data, the Fraxinus excelsior Fusarium isolate could probably be considered a new species of the Fusarium genus.
Comparison of fine-needle aspiration and fine-needle biopsy devices for endoscopic ultrasound-guided sampling of solid lesions: a systemic review and meta-analysis
Authors: van Riet Priscilla A. , Erler Nicole S. , Bruno Marco J. , Cahen Djuna L.
Published: June 2020

Background Endoscopic ultrasound (EUS)-guided tissue acquisition is extensively used, but the optimal sampling device is still a matter of debate. We performed meta-analyses on studies comparing fine-needle aspiration (FNA) with fine-needle biopsy (FNB) needles, and studies comparing different FNB needles.

Methods Online databases were searched for randomized controlled trials (RCTs) of at least 50 cases with a suspected solid pancreatic or nonpancreatic lesion that compared FNA with FNB needles. Outcome measures included diagnostic accuracy, adequacy, number of passes, presence of tissue cores, and adverse events. We also performed meta-regression analysis on the effect of FNB design on diagnostic accuracy. Quality was assessed using the QUADAS-2 tool.

Results 18 RCTs comparing FNA with FNB needles were included. FNB provided a higher pooled diagnostic accuracy (87 % vs. 80 %; P = 0.02) and tissue core rate (80 % vs. 62 %; P = 0.002), and allowed diagnosis with fewer passes (P = 0.03), in both pancreatic and nonpancreatic lesions. A total of 93 studies were included comparing different FNB devices. Pooled diagnostic accuracy was higher for forward-facing bevel needles than for the reverse bevel needle. In this analysis, study quality was low and heterogeneity was high (I2  = 80 %).

Conclusion FNB outperformed FNA when sampling pancreatic and nonpancreatic lesions. Forward-facing bevel FNB needles seemed to outperform the reverse bevel FNB needle, but the low quality of evidence prevents us from making strong recommendations on the optimal FNB design.
Ethical Considerations for Healthcare Organizations
Authors: Rao Paul R.
Published: June 2020

Ethical misbehavior in the delivery of healthcare creates harm not only to individual therapists and administrators who might choose to overstep ethical boundaries but also, more broadly, causes harm to patients, to healthcare organizations, to professional organizations, and ultimately to society. Both corporate codes of conduct and professional codes of ethics are important, because they set standards of conduct and penalize noncompliant or unethical conduct. The purposes of this article are (1) to differentiate corporate compliance from ethics in a healthcare organization; (2) to explain the application of ethics principles to organizational and professional behaviors; (3) to discuss three important ethical issues (cultural competence, conflict of interest, and employer demands); and (4) to emphasize that, whether applying a corporate code of conduct or a professional code of ethics (or both), the integrity of each individual is essential to ethical behavior. To illustrate these concepts, ASHA's Code of Ethics is discussed in detail (including the ethics complaint adjudication process), and hypothetical case studies are presented under the macro headings of Cultural Competence, Conflict of Interest, and Employer Demands.
Ethical Issues in Dysphagia Management
Authors: Leslie Paula , Lisiecka Dominika
Published: June 2020

Dysphagia management is complex and requires balancing individuals' preferences, quality of life, and medical consequences. Ethical challenges are not uncommon given the complexity of dysphagia. Professionals must engage in ethical reflection and shared decision-making when managing dysphagia. Recognizing one's own presuppositions and beliefs may be fundamental to ensuring an ethical approach. The goal of this article is to apply principles of ethics using hypothetical case studies of dysphagia. To this end, we will describe the challenges of working with the disorder of dysphagia; the influence of culture on decision-making about eating and feeding; the importance of information disclosure and respect for individuals' refusal of recommendations; and the interplay of ethical reflection, evidence, and clinical judgment when making complex dysphagia management decisions. These concepts should be kept in mind to ensure compassionate and competent care of the person with eating, drinking, or swallowing problems and their family caregivers.
Osteotomies for the Management of Medial Compartment Defects of the Knee
Authors: Grimm Nathan L. , Levy Benjamin J. , Jimenez Andrew E. , Arciero Robert A.
Published: June 2020

For nearly three-quarters of a century the proximal tibia osteotomy has been used as an effective treatment for cartilage injuries of the knee. Over this same timeframe several advancements have been made in our diagnostic, preoperative planning, and technical execution of this procedure. As such, good-to-excellent short-, mid-, and long-term outcomes have been reported. Since its inception, the most important step in deciding on this procedure is identifying the ideal candidate. This candidate should be a young patient (<55 years old), active, with isolated medial compartment arthrosis without significant comorbidities. With appropriate patient selection and careful preoperative planning, the patient should achieve excellent results and high satisfaction.
The Effect of Perforator Skeletonization on Pedicled Fasciocutaneous Flaps of the Lower Extremity: A Systematic Review
Authors: Soteropulos Carol E. , Shulzhenko Nikita O. , Nayar Harry S. , Poore Samuel O.
Published: June 2020

Background Lower extremity defects often require free tissue transfer due to a paucity of local donor sites. Locoregional perforator-based flaps offer durable, single-stage reconstruction while avoiding the pitfalls of microsurgery. Multiple harvest techniques are described, yet few studies provide outcome comparisons. Specifically, no study has examined the impact of perforator flap pedicle skeletonization on reconstructive outcomes. This systematic review characterizes technique and impact of pedicle skeletonization on perforator-based fasciocutaneous flaps of the lower extremity.

Methods PubMed, Scopus, and the Cochrane Central Register of Controlled Trials were reviewed for literature examining perforator-based fasciocutaneous flaps from knee to ankle, from January 2000 through November 2018. The Preferred Reporting Items for Systematic Reviews-Individual Participant Data (PRISMA-IPD) structure was used.

Results Thirty-six articles were included for quantitative analysis. Of 586 flaps, 365 were skeletonized (60.1%) with 58 major (9.9%) and 19 minor complications (3.2%). With skeletonization, overall reoperative rate was higher (odds ratio [OR]: 9.71, p = 0.004), specifically in propeller (OR: 12.50, p = 0.004) and rotational flaps (OR: 18.87, p = 0.004). The complication rate of rotational flaps also increased (OR: 2.60, p = 0.04). Notably, skeletonization reduced complications in flaps rotated 90 degrees or more (OR: 0.21, p = 0.02). Reoperative rate of distal third defects (OR: 14.08, p = 0.02), flaps over 48 cm2 (OR: 33.33, p = 0.01), and length to width ratios over 1.75 (OR: 7.52, p = 0.03) was increased with skeletonization. Skeletonization increased complications in traumatic defects (OR: 2.87, p = 0.04) and reduced complications in malignant defects (OR: 0.10, p = 0.01).

Conclusion Pedicled, perforator-based flaps can provide a reliable locoregional alternative to free tissue transfer for lower extremity defects. Though skeletonization increased the overall reoperative rate, the complication rate for flaps with 90 degrees or more of rotation was significantly reduced. This suggests skeletonization should be considered when large rotational movements are anticipated to reduce complications that can arise from pedicle compression and venous congestion.
Does nuclear permutation symmetry allow dynamical localization in symmetric double-well achiral molecules?
Authors: Bouakline Foudhil
Published: June 2020

We discuss the effect of molecular symmetry on coherent tunneling in symmetric double-well potentials whose two molecular equilibrium configurations are interconverted by nuclear permutations. This is illustrated with vibrational tunneling in ammonia molecules, electronic tunneling in the dihydrogen cation, and laser-induced rotational tunneling of homonuclear diatomics. In this contribution, we reexamine the textbook picture of coherent tunneling in such potentials, which is depicted with a wavepacket shuttling back and forth between the two potential-wells. We show that the common application of this picture to the aforementioned molecules contravenes the principle of the indistinguishability of identical particles. This conflict originates from the sole consideration of the dynamics of the tunneling-mode, connecting the double-well energy minima, and complete omission of all the remaining molecular degrees of freedom. This gives rise to double-well wavepackets that are nonsymmetric under nuclear permutations. To obey quantum statistics, we show that the double-well eigenstates composing these wavepackets must be entangled with the wavefunctions that describe all the omitted molecular modes. These wavefunctions have compensating and opposite nuclear permutation symmetry. This in turn leads to complete quenching of interference effects behind localization in one potential-well or another. Indeed, we demonstrate that the reduced density of probability of the symmetrized molecular wavefunction, where all the molecular coordinates but the tunneling-mode are integrated out, is symmetrically distributed over the two potential-wells, at all times. This applies to any multilevel wavepacket of isotropic or fully aligned symmetric double-well achiral molecules. However, in the case of coherent electronic or vibrational tunneling, fully aligned molecules may exhibit dynamical localization in the space-fixed frame, where the tunneling-mode density shuttles between the opposite directions of the alignment axis. This dynamical spatial-localization results from linear combinations of molecular states that have opposite parity. In summary, this study shows that dynamical localization of the tunneling-mode density on either of the two indistinguishable molecular equilibrium configurations of symmetric double-well achiral molecules is forbidden by quantum statistics, whereas its dynamical localization in the space-fixed frame is allowed by parity. The subtle distinction between these two types of localization has far-reaching implications in the interpretation of many ultrafast molecular dynamics experiments.
Thermal tracing of a highly reconfigurable and wideband infrared heat sensor based on vanadium dioxide
Authors: Moradi Tara , Hatef Ali
Published: June 2020

In this paper, we investigate the thermodynamic properties of a highly reconfigurable and broadband perfect metamaterial absorber in the near-infrared region. Our model is a periodic nanostructure composed of an array of L-shaped hybrid gold and vanadium dioxide nanostructures on gold and glass substrates. The reconfigurability of the nanostructure is based on the metal–insulator transition of vanadium dioxide. The degree of reconfigurability depends on the temperature of the vanadium dioxide nanostructure. In order to study the photo-thermal effect on the reconfigurability of the nanostructure, we irradiate it with a time-dependent Gaussian pulse laser with a 1.5 ns pulse width. Our main purpose is twofold. On the one hand, we aim to investigate how the laser increases the temperature of the nanostructure, and on the other hand, we intend to explore whether the temperature modifies the absorption and reflection of the array. Our results reveal that the VO2 fully transitions to its metallic phase when the fluence of the incident laser is adjusted to 17.8 mJ/cm2.
Bifunctional superlens for simultaneous flexural and acoustic wave superfocusing
Authors: Zhu Yifan , Cao Liyun , Merkel Aurélien , Fan Shi-Wang , Assouar Badreddine
Published: June 2020

Superfocusing of acoustic and elastic waves is generally achieved by the combination of negative refraction and the enhancement of the evanescent waves. Here, we numerically and experimentally demonstrate the bifunctionality of a superlens that can simultaneously focus acoustic and flexural waves beyond the diffraction limit. The designed structure is composed of a two-dimensional arrangement of pillars that act as rigid scatterers for the sound waves and as resonant scatterers for the flexural waves. The band structure presents modes with negative dispersion bands allowing negative refraction for both types of waves within the frequency range of 6.9–7.4 kHz, which is induced by the Bragg scattering effect. Edge modes that enhance the evanescent waves through resonant coupling appear around 7.2 kHz for the flexural and sound wave. The simultaneous superlensing is then observed at this frequency. Our finding will enlighten multiphysical and multifunctional wave manipulations and could have pragmatic applications involving multiwave devices.
Growth mechanism and domain structure study on epitaxial BiFeO3 film grown on (La0.3Sr0.7)(Al0.65Ta0.35)O3
Authors: Bae In-Tae , Yasui Shintaro , Ichinose Tomohiro , Itoh Mitsuru , Shiraishi Takahisa , Kiguchi Takanori , Naganuma Hiroshi
Published: June 2020

A BiFeO3 (BFO) film is epitaxially grown on an (La0.3Sr0.7)(Al0.65Ta0.35)O3 (LSAT) substrate to investigate the lattice mismatch effect on the domain structure and lattice strain status within the BFO film. Atomic resolution scanning transmission electron microscope image, selected area electron diffraction (SAED) patterns, and X-ray reciprocal space mapping (XRSM) data clearly reveal that the lattice strain originating from the lattice mismatch between BFO and LSAT is relaxed by causing misfit dislocations in the BFO film. The SAED and XRSM data indicate that the crystal structure of BFO film is rhombohedral with the space group R3c. In particular, XRSM data acquired along two different in-plane orientations reveal that the BFO layer consists of two different domains that were 90° off each other with respect to the surface normal orientation. An atomistic model based on the crystal orientation relation found by SAED and XRSM shows that (1) the ferroelectric polarization axes of both domains are 35.6° with respect to the BFO film surface and (2) the two domains are consistent with the so-called 71° (and/or 109°) ferroelectric domains reported previously. The lattice mismatch of ∼2.8% calculated based on the epitaxial relation is proposed to be too large to be stored as elastic strain energy within the BFO layer.
Optical response of nickel-based superalloy Inconel-718 for applications in additive manufacturing
Authors: Curry Erin B. , Sahoo Sanjubala , Herrera Chloe , Sochnikov Ilya , Pamir Alpay S. , Hebert Rainer J. , Willis Brian G. , Qi Jie , Hancock Jason N.
Published: June 2020

We present a broadband infrared and optical study of the compositionally complex nickel-based superalloy Inconel-718, a common material used in additive manufacturing using the direct metal laser sintering (DMLS) technique. We find a broad, featureless spectral emissivity, which is consistent with dc transport measurements and contextualize the results against literature reports of disordered metals. We show that electronic structure calculations based on first-principles modeling can explain most of the spectral weight distribution and show that the peculiar infrared optical properties in this class of materials can present challenges in accurately reporting remote temperature sensing in DMLS.
Temperature-dependent anisotropic magnetoresistance and spin-torque-driven vortex dynamics in a single microdisk
Authors: Lendínez Sergi , Polakovic Tomas , Ding Junjia , Jungfleisch M. Benjamin , Pearson John , Hoffmann Axel , Novosad Valentine
Published: June 2020

Spin–orbit-torque-driven dynamics have recently gained interest in the field of magnetism due to the reduced requirement of current densities and an increase in efficiency, as well as the ease of implementation of different devices and materials. From a practical point of view, the low-frequency dynamics below 1 GHz is particularly interesting since dynamics associated with magnetic domains lie in this frequency range. While spin-torque excitation of high-frequency modes has been extensively studied, the intermediate low-frequency dynamics have received less attention, although spin torques could potentially be used for both manipulation of the spin texture and the excitation of dynamics. In this work, we demonstrate that it is possible to drive magnetic vortex dynamics in a single microdisk by spin-Hall torque at varying temperatures and relate the results to transport properties. We find that the gyrotropic mode of the core couples to the low-frequency microwave signal and produces a measurable voltage. The dynamic measurements are in agreement with magnetic transport measurements and are supported by micromagnetic simulations. Our results open the door for integrating magnetic vortex devices in spintronic applications.
Driving torsion scans with wavefront propagation
Authors: Qiu Yudong , Smith Daniel G. A. , Stern Chaya D. , Feng Mudong , Jang Hyesu , Wang Lee-Ping
Published: June 2020

The parameterization of torsional/dihedral angle potential energy terms is a crucial part of developing molecular mechanics force fields. Quantum mechanical (QM) methods are often used to provide samples of the potential energy surface (PES) for fitting the empirical parameters in these force field terms. To ensure that the sampled molecular configurations are thermodynamically feasible, constrained QM geometry optimizations are typically carried out, which relax the orthogonal degrees of freedom while fixing the target torsion angle(s) on a grid of values. However, the quality of results and computational cost are affected by various factors on a non-trivial PES, such as dependence on the chosen scan direction and the lack of efficient approaches to integrate results started from multiple initial guesses. In this paper, we propose a systematic and versatile workflow called TorsionDrive to generate energy-minimized structures on a grid of torsion constraints by means of a recursive wavefront propagation algorithm, which resolves the deficiencies of conventional scanning approaches and generates higher quality QM data for force field development. The capabilities of our method are presented for multi-dimensional scans and multiple initial guess structures, and an integration with the MolSSI QCArchive distributed computing ecosystem is described. The method is implemented in an open-source software package that is compatible with many QM software packages and energy minimization codes.
A simple molecular orbital picture of RIXS distilled from many-body damped response theory
Authors: Nanda Kaushik D. , Krylov Anna I.
Published: June 2020

Ab initio calculations of resonant inelastic x-ray scattering (RIXS) often rely on damped response theory, which prevents the divergence of response solutions in the resonant regime. Within the damped response theory formalism, RIXS moments are expressed as the sum over all electronic states of the system [sum-over-states (SOS) expressions]. By invoking resonance arguments, this expression can be reduced to a few terms, an approximation commonly exploited for the interpretation of computed cross sections. We present an alternative approach: a rigorous formalism for deriving a simple molecular orbital picture of the RIXS process from many-body calculations using the damped response theory. In practical implementations, the SOS expressions of RIXS moments are recast in terms of matrix elements between the zero-order wave functions and first-order frequency-dependent response wave functions of the initial and final states such that the RIXS moments can be evaluated using complex response one-particle transition density matrices (1PTDMs). Visualization of these 1PTDMs connects the RIXS process with the changes in electronic density. We demonstrate that the real and imaginary components of the response 1PTDMs can be interpreted as contributions of the undamped off-resonance and damped near-resonance SOS terms, respectively. By analyzing these 1PTDMs in terms of natural transition orbitals, we derive a rigorous, black-box mapping of the RIXS process into a molecular orbital picture. We illustrate the utility of the new tool by analyzing RIXS transitions in the OH radical, benzene, para-nitroaniline, and 4-amino-4′-nitrostilbene. These examples highlight the significance of both the near-resonance and off-resonance channels.
Dust ion acoustic multi-shock wave excitations in the weakly relativistic plasmas with nonthermal nonextensive electrons and positrons
Authors: Hafez M. G. , Singh Sudhir , Sakthivel R. , Ahmed S. F.
Published: June 2020

This article investigates the dust ion acoustic multi-shock wave excitations in weakly relativistic multi-component plasma by assuming nonthermal, nonextensive electrons and positrons, relativistic ion fluid having kinetic viscosity and immobile dust. Burgers equation is derived to investigate such excitations by applying the reductive perturbation method. The exponential functions are directly implemented to determine the novel multi-shock wave solution of Burgers equation. The dust ion acoustic (DIA) multi-shock wave excitations are investigated systematically to reveal the effects of parameters, namely, viscosity coefficient of ions, positron to electron density ratio, immobile dust to electron density ratio, ion to electron temperature ratio, electron to positron temperature ratio, and relativistic streaming factor of ions in the presence of nonthermal, nonextensive, and concurrently acting nonthermal and nonextensive electrons as well as positrons. It is found that the amplitudes and widths of not only single, but also multi-shock wave compressive and rarefactive electrostatic potential structures are changed with the influence of all plasma parameters. The obtained results may be useful to analyze the nature of DIA multi-shock wave phenomena in various astrophysical as well as space environments (particularly, in pulsar relativistic winds with supernova ejecta) and future studies in plasma laboratory.
Accurate and fast evaluation of orthotropic thermal diffusivity within a membrane: A theoretical approach
Authors: Battaglia Jean-Luc , Chassain Clément , Ruffio Emmanuel
Published: June 2020

In this paper, we propose a theoretical investigation of several configurations based on the infrared photothermal radiometry in order to estimate the thermal diffusivity of isotropic and orthotropic membranes. The front-face and rear-face experimental configurations are considered and show complementary results. Analytical approximations based on characteristic values of the simulated variations of the observed physical quantities, such as the phase or the amplitude, as well as the geometrical parameters are presented. Those approximations are reliable on a large range of thermal properties that make them useful for a large variety of applications. The case of semi-transparent membranes is also treated theoretically, which requires the implementation of non-linear least square minimization to estimate the in-plane thermal diffusivity.
Experimental analysis of the spin–orbit coupling dependence on the drift velocity of a spin packet
Authors: Kawahala N. M. , Moraes F. C. D. , Gusev G. M. , Bakarov A. K. , Hernandez F. G. G.
Published: June 2020

Spin transport was studied in a two-dimensional electron gas hosted in a wide GaAs quantum well occupying two subbands. Using space and time Kerr rotation microscopy to image drifting spin packets under an in-plane accelerating electric field, optical injection and detection of spin polarization were achieved in a pump–probe configuration. The experimental data exhibited high spin mobility and long spin lifetimes allowing us to obtain the spin–orbit fields as a function of the spin velocities. Surprisingly, above moderate electric fields of 0.4 V/cm with velocities higher than 2 µm/ns, we observed a dependence of both bulk and structure-related spin–orbit interactions on the velocity magnitude. A remarkable feature is the increase in the cubic Dresselhaus term to approximately half of the linear coupling when the velocity is raised to 10 µm/ns. In contrast, the Rashba coupling for both subbands decreases to about half of its value in the same range. These results yield new information on the application of drift models in spin–orbit fields and about limitations for the operation of spin transistors.
What does it mean to be an isolating language?
Authors: Gil David
Published: June 2020

This chapter poses the question “What does it mean to be an
isolating language?” and addresses it by offering a case study of such a language, Riau
Indonesian. First, this chapter surveys the debate concerning the viability of the
notion of word as a comparative concept, proposes a definition of word as a cut-off
point between two distinct levels of structure, morphology and syntax, and then follows
with a definition of an isolating language as one lacking a robust structural unit of
word. Next, the chapter presents an extensive exploration of wordhood in Riau
Indonesian, examining 14 potential sources of evidence for word structure. Overall, the
evidence for wordhood is shown to be sparse, thereby justifying the characterisation of
Riau Indonesian as an isolating language and at the same time demonstrating what an
isolating language may look like.
Becoming Austronesian
Authors: Donohue Mark , Denham Tim
Published: June 2020

We examine the spread of Austronesian languages as a process that
proceeded in different ways at different times, even in the same locale. We examine the
many ways a language can show ‘Austronesian traits’, and confront this with the known
presence of pre-Austronesian languages across Island Southeast Asia, and the inferred
similarity of social processes between mainland and Island Southeast Asia. We argue that
many languages which are classified as Austronesian are indeed exemplary Austronesian
languages, but that many others should be considered to be the outcome of creolisation
processes, and yet others show the traces of scenarios involving (imperfect) language
shift from earlier non-Austronesian languages. Indeed, ‘many’ of the languages
should be considered to be non-Austronesian languages (‘Papuan’) with (in some cases
minimal) Austronesian (lexical) veneers.
Demands of professional cycling races: Influence of race category and result
Authors: Van Erp Teun , Sanders Dajo
Published: June 2020

This study analyses the influence of race category and result on the demands of professional cycling races. In total, 2920 race files were collected from 20 male professional cyclists, within a variety of race categories: Single‐day (1.WT) and multi‐day (2.WT) World Tour races, single‐day (1.HC) and multi‐day (2.HC) Hors Catégorie races and single‐day (1.1) and multi‐day (2.1) category 1 races. Additionally, the five cycling “monuments” were analysed separately. Maximal mean power outputs (MMP) were measured across a broad range of durations. Volume and load were large to very largely (d = 1.30–4.80) higher in monuments compared to other single‐day race categories. Trivial to small differences were observed for most intensity measures between different single‐day race categories, with only RPE and sRPE·km−1 being moderately (d = 0.70–1.50) higher in the monuments. Distance and duration were small to moderately (d = 0.20–0.80) higher in 2.WT races compared to 2.HC and 2.1 multi‐day race categories with only small differences in terms of load and intensity. Generally, higher ranked races (i.e. Monuments, 2.WT and GT) tend to present with lower shorter‐duration MMPs (e.g. 5–120 sec) compared to races of “lower rank” (with less differences and/or mixed results being present over longer durations), potentially caused by a “blunting” effect of the higher race duration and load of higher ranked races on short duration MMPs. MMP were small to largely higher over shorter durations (<5 min) for a top‐10 result compared to no top‐10, within the same category.
Cathodoluminescence visualisation of local thickness variations of GaAs/AlGaAs quantum-well tubes on nanowires
Authors: Gustafsson Anders , Jiang Nian , Zheng Changlin , Etheridge Joanne , Gao Qiang , Tan Hark Hoe , Jagadish Chennupati , Wong-Leung Jennifer
Published: June 2020

We present spatially and spectrally resolved emission from nanowires with a thin radial layer of GaAs embedded in AlGaAs barriers, grown radially around taper-free GaAs cores. The GaAs layers are thin enough to show quantization, and are quantum wells. Due to their shape, they are referred to as quantum well tubes (QWTs). We have investigated three different nominal QWT thicknesses: 1.5, 2.0, and 6.0 nm. They all show average emission spectra from the QWT with an energy spread corresponding to a thickness variation of ±30%. We observe no thickness gradient along the length of the nanowires. Individual NWs show a number of peaks, corresponding to different QW thicknesses. Apart from the thinnest QWT, the integrated emission from the QWTs shows homogeneous emission intensity along the NW. The thinnest QWTs show patchy emission patterns due to the incomplete coverage of the QWT. We observe a few NWs with larger diameters. The QWTs in these NWs show spatially resolved variations across the NW. An increase in the local thickness of the QWT at the corners blocks the diffusion of carriers from facet to facet, thereby enabling us to visualise the thickness variations of the radial quantum wells.
Divergence of the dielectric constant in ultrathin granular metal films near the percolation threshold
Authors: Bakkali H , Blanco E , Lofland S E , Domínguez M
Published: June 2020

We report on the electronic and optical properties of ultrathin granular films. We demonstrate that the static dielectric constant increases with thickness in the dielectric regime and diverges at the critical thickness, as predicted by classical percolation theory. However, for thicker samples, the dc conductivity does not obey scaling laws due to the presence of tunneling conduction. In this region the dielectric constant is positive, and the electronic transport is not metallic but can be described by Jonscher’s universal power law, even though there is a Drude-like response indicating the presence of free charge carriers. Only for thicker films when the dielectric constant becomes negative is there metallic conduction.
Study on the effect of ZIF-8 nanoparticles on the transport behavior of CH4 and CO2 gases in polysulfone membrane
Authors: Ch’ng Wei Mann Christine , Fong Yeong Yin , Jusoh Norwahyu
Published: June 2020

CO2 capture has been given much attention worldwide in order to minimize the CO2 emission in protecting the harmful impact on climate change. In this study, zeolitic imidazolate framework-8 (ZIF-8) nanoparticles was embedded in polysulfone (PSf) polymer and the changes of the transport behavior of CO2 and CH4 single gases of the resultant membranes were investigated. The solubility of the gases through the membranes were determined by using dual-volume sorption cell at 5 bar and room temperature. Subsequently, the diffusion coefficients were determined from the permeability and solubility values. From the results obtained, the CO2 sorption values for both resultant membranes were higher than that of CH4. Meanwhile, the membrane incorporated with ZIF-8 demonstrated greater CO2 sorption capacity compared to pure PSf membrane. It can be concluded that the improvement of CO2 permeability after the incorporation of ZIF-8 into PSf is mainly due to the enhancement in solubility and diffusivity of the membrane.
Wall thickness dependencies of carbon nanotube reinforced nanocomposites
Authors: Ahmed K S , Islam M W , Ibrahim I
Published: June 2020

Indentation analyses are conducted to investigate the CNT’s wall thickness dependencies of the mechanical properties of nanocomposites. This study incorporates Berkovich nanoindentation analyses for chemically non-bonded CNT/matrix interface, including the size effects of nanocomposites. For non-bonded interface, the properties of nanocomposite are generally controlled by mechanical interlocking, thermal residual stress, Poisson’s contraction and van der Waal’s (vdW) interaction between CNT and matrix. Considering all these parameters, a series of finite element models for nano-indentation tests have been constructed, aiming to investigate the mechanical properties of CNT reinforced nanocomposites. The model is validated and numerical results are compared with that of existing experimental indentation test. Analysis has been run for ten different wall thicknesses of CNTs in a range of wall thickness starting from 0.034 nm to 0.334 nm. Elasto-plastic behavior of steel and CNT including strain gradient is considered in the program. The study on wall thickness dependencies of CNTs in nanocomposite shows that mechanical properties of nanocomposites largely depends on the wall thickness of CNTs. A minimum wall thickness for a particular tube diameter to achieve a pick value of hardness and modulus of elasticity of nanocomposites is determined. The minimum wall thickness of CNTs is suggested to be 0.2 for an outer diameter of 1nm in order to achieve the maximum value of composite properties. In addition, a wall thickness smaller than 0.05 nm may even reduce the hardness and modulus of elasticity of CNT reinforced composites compare to that of pure matrix.