bluuebunny/crossref_metadata_2025 huggingface dataset:
Protoplanetary disk formation from the collapse of a prestellar core
Authors: Lee Yueh-Ning , Charnoz Sébastien , Hennebelle Patrick
Published: March 2021

Context.Between the two research communities that study star formation and protoplanetary disk evolution, only a few efforts have been made to understand and bridge the gap between studies of a collapsing prestellar core and a developed disk. While it has generally been accepted for about a decade that the magnetic field and its nonideal effects play important roles during the stellar formation, simple models of pure hydrodynamics and angular momentum conservation are still widely employed in the studies of disk assemblage in the framework of the so-called alpha-disk model because these models are simple.

Aims.We revisit the assemblage phase of the protoplanetary disk and employ current knowledge of the prestellar core collapse.

Methods.We performed 3D magnetohydrodynamic (MHD) simulations with ambipolar diffusion and full radiative transfer to follow the formation of the protoplanetary disk within a collapsing prestellar core. The global evolution of the disk and its internal properties were analyzed to understand how the infalling envelope regulates the buildup and evolution of the disk. We followed the global evolution of the protoplanetary disk from the prestellar core collapse during 100 kyr with a reasonable resolution of AU. Two snapshots from this reference run were extracted and rerun with significantly increased resolution to resolve the interior of the disk.

Results.The disk that formed under our simulation setup is more realistic and agrees with recent observations of disks around class 0 young stellar objects. The source function of the mass flux that arrives at the disk and the radial mass accretion rate within the disk are measured and compared to analytical self-similar models based on angular momentum conservation. The source function is very centrally peaked compared to classical hydrodynamical models, implying that most of the mass falling onto the star does not transit through the midplane of the disk. We also found that the disk midplane is almost dead to turbulence, whereas upper layers and the disk outer edge are highly turbulent, and this is where the accretion occurs. The snow line, located at about 5–10 AU during the infall phase, is significantly farther away from the center than in a passive disk. This result might be of numerical origin.

Conclusions.We studied self-consistent protoplanetary disk formation from prestellar core collapse, taking nonideal MHD effects into account. We developed a zoomed rerun technique to quickly obtain a reasonable disk that is highly stratified, weakly magnetized inside, and strongly magnetized outside. During the class 0 phase of protoplanetary disk formation, the interaction between the disk and the infalling envelope is important and ought not be neglected. We measured the complex flow pattern and compared it to the classical models of pure hydrodynamical infall. Accretion onto the star is found to mostly depend on dynamics at large scales, that is, the collapsing envelope, and not on the details of the disk structure.
Evidence of intra-binary shock emission from the redback pulsar PSR J1048+2339
Authors: Miraval Zanon A. , D’Avanzo P. , Ridolfi A. , Coti Zelati F. , Campana S. , Tiburzi C. , de Martino D. , Muñoz Darias T. , Bassa C. G. , Zampieri L. , Possenti A. , Ambrosino F. , Papitto A. , Baglio M. C. , Burgay M. , Burtovoi A. , Michilli D. , Ochner P. , Zucca P.
Published: March 2021

We present simultaneous multiwavelength observations of the 4.66 ms redback pulsar PSR J1048+2339. We performed phase-resolved spectroscopy with the Very Large Telescope (VLT) searching for signatures of a residual accretion disk or intra-binary shock emission, constraining the companion radial velocity semi-amplitude (K2), and estimating the neutron star mass (MNS). Using the FORS2-VLT intermediate-resolution spectra, we measured a companion velocity of 291 < K2 < 348 km s−1 and a binary mass ratio of 0.209 < q < 0.250. Combining our results for K2 and q, we constrained the mass of the neutron star and the companion to (1.0 < MNS < 1.6) sin−3 i M⊙ and (0.24 < M2 < 0.33) sin−3i M⊙, respectively, where i is the system inclination. The Doppler map of the Hα emission line exhibits a spot feature at the expected position of the companion star and an extended bright spot close to the inner Lagrangian point. We interpret this extended emission as the effect of an intra-binary shock originating from the interaction between the pulsar relativistic wind and the matter leaving the companion star. The mass loss from the secondary star could be either due to Roche-lobe overflow or to the ablation of its outer layer by the energetic pulsar wind. Contrastingly, we find no evidence for an accretion disk. We report on the results of the Sardinia Radio Telescope (SRT) and the Low-Frequency Array (LOFAR) telescope simultaneous radio observations at three different frequencies (150 MHz, 336 MHz, and 1400 MHz). No pulsed radio signal is found in our search. This is probably due to both scintillation and the presence of material expelled from the system which can cause the absorption of the radio signal at low frequencies. The confirmation of this hypothesis is given by another SRT observation (L-band) taken in 2019, in which a pulsed signal is detected. Finally, we report on an attempt to search for optical pulsations using IFI+Iqueye mounted at the 1.2 m Galileo telescope at the Asiago Observatory.
Moving solar radio bursts and their association with coronal mass ejections
Authors: Morosan D. E. , Kumari A. , Kilpua E. K. J. , Hamini A.
Published: March 2021

Context. Solar eruptions, such as coronal mass ejections (CMEs), are often accompanied by accelerated electrons that can in turn emit radiation at radio wavelengths. This radiation is observed as solar radio bursts. The main types of bursts associated with CMEs are type II and type IV bursts that can sometimes show movement in the direction of the CME expansion, either radially or laterally. However, the propagation of radio bursts with respect to CMEs has only been studied for individual events.

Aims. Here, we perform a statistical study of 64 moving bursts with the aim to determine how often CMEs are accompanied by moving radio bursts. This is done in order to ascertain the usefulness of using radio images in estimating the early CME expansion.

Methods. Using radio imaging from the Nançay Radioheliograph (NRH), we constructed a list of moving radio bursts, defined as bursts that move across the plane of sky at a single frequency. We define their association with CMEs and the properties of associated CMEs using white-light coronagraph observations. We also determine their connection to classical type II and type IV radio burst categorisation.

Results. We find that just over a quarter of type II and half of type IV bursts that occurred during the NRH observing windows in Solar Cycle 24 are accompanied by moving radio emission. All but one of the moving radio bursts are associated with white–light CMEs and the majority of moving bursts (90%) are associated with wide CMEs (> 60° in width). In particular, all but one of the moving bursts corresponding to type IIs are associated with wide CMEs; however, and unexpectedly, the majority of type II moving bursts are associated with slow white–light CMEs (< 500 km s−1). On the other hand, the majority of moving type IV bursts are associated with fast CMEs (> 500 km s−1).

Conclusions. The observations presented here show that moving radio sources are almost exclusively associated with CMEs. The majority of events are also associated with wide CMEs, indicating that strong lateral expansion during the early stages of the eruption may play a key role in the occurrence of the radio emission observed.
Handschuhe, Helm und Schweregefühl – Das T4-Syndrom
Authors: Löscher Sebastian
Published: March 2021

Bilaterale Parästhesien der Finger, Hände und Unterarme in Kombination mit Kopfschmerzen und interskapulären Beschwerden. Was zunächst wie eine willkürliche Ansammlung von Symptomen klingt, wird in der manuellen Medizin oft als T4-Syndrom zusammengefasst. Ob die weitverbreitete Theorie einer thorakal lokalisierten sympathischen Dysfunktion mit dem Gefühl des Patienten, Handschuhe und einen Helm zu tragen, überhaupt haltbar ist, ist fraglich.
Motivierendes Puzzleteil – Therapeutisches Klettern bei Skoliose
Authors: Dech Silas , Kittel René
Published: March 2021

Die Therapie einer idiopathischen Skoliose ist oft langfristig und mühsam. Eine motivierende Ergänzung zu den klassischen Interventionen – vor allem für junge Patienten – ist das Therapeutische Klettern. Mithilfe des sogenannten Potsdamer Modells, das dem Klettern den trainingsmedizinischen Rahmen gibt, können Therapeuten das bewegungsspezifische Puzzleteil in der Skoliosetherapie füllen.
Emergency Department Management of Mild Traumatic Brain Injury in New Delhi–A Single Institute Cohort Management Data
Authors: Choudhary Ajay , Kumar Ashok , Sharma Rajesh Kumar , Varshney Rahul , Munjal Satya Shiva , Kaushik Kaviraj , Gupta Laxmi Narayan
Published: March 2021

Introduction The purpose of this study is to compare the current clinical management practices and decision guidelines of the Brain Trauma Foundation (BTF) for mild traumatic brain insult with line of treatment followed at our center to identify the clinically significant treatment outcome in pediatric to elderly patients.

Materials and Methods This is a questionnaire-based prospective observational study at the emergency department of neurosurgery in Dr. Ram Manohar Lohia (RML) Hospital, New Delhi. A registry questionnaire was administered to all the eligible subjects by the neurosurgery resident in emergency department (ED) to correlate clinical status, severity of traumatic brain injury (TBI) and associated comorbid conditions and its outcome after management.

Results Out of 154 mild TBI cases attending ED, 115 (74.7%) were males and 39 (25.3%) were females, with average age of 27 years. Of the patients with mild TBI, road traffic accidents (RTA) were the main cause (50.6%), followed by fall from height (42.9%), assault and sports-related injury (6.4%). Of the total, 96.1% underwent CT. Of these, 31.8% found abnormal CT results, 27.5% received wound treatment care, and 9.1% received emergency care. Nearly 30.5% were admitted and 1.3% patients were died in the hospital, 75.3% patients were discharged and 23.4% were referred to other department for associated co morbid conditions.

Conclusion The present study identified deficiencies in and variation around several important aspects of ED care. The development of BTF guidelines specific for mild TBI could reduce variation and improve emergency care for this injury.
Abdominal Wall Hernias: An Epidemiological Profile and Surgical Experience from a Rural Medical College in Central India
Authors: Pandya Bharati , Huda Tanweerul , Gupta Dilip , Mehra Bhupendra , Narang Ravinder
Published: March 2021

Background Abdominal wall hernia is a common surgical entity worldwide with groin hernias having the most common presentation among them. They are a cause of morbidity and mortality if not addressed in time. A variety of surgical methods are available for the repair of hernias. The tension-free repair using synthetic mesh has the least recurrence and is the most accepted.

Aim To describe the surgical burden and clinical profile of abdominal wall hernias as well as experiences in their management in a rural setup.

Methods This was a retrospective observational study of all the cases of abdominal wall hernias presenting to various surgical divisions of Mahatma Gandhi Institute of Medical Sciences, Sevagram, during a two-year period from December 2011 to November 2013. Relevant details were collected from the hospital information statistics and patient file records and analysis of obtained data was done.

Result A total of 910 out of 90,056 surgical outpatients (10.10%) seen during this period had abdominal wall hernias; 816 (89.67%) got operated. A total of 163 (20%) of 816 were operated in an emergency. Groin hernias were the most common 653 (80%), followed by incisional 82 (10%), umbilical and paraumbilical 41 (5%), epigastric 33 (4%), and rarer hernias in 8 (1%). Of 816 operations, 24 (2.9%) had recurrent hernias and 83 (10.17%) were pediatric patients. Male to female ratio was 9:1 in adults and 4:1 in children. The median age among adults was 49 years (range: 14–95 years), and among the pediatric age group, it was 7 years (range: 3 months–14 years). The majority of the adult patients were from a low-income group and presented more than 2 years after symptoms appeared. Comorbid conditions encountered were hypertension in 212 (26%), diabetes in 155 (19%), chronic airway disorders in 449 (55%), cardiac problems in 163 (20%), obesity in 10 (1.2%), and chronic renal failure and liver disorder in 82 (1%). Predisposing factors in the majority of the patients were chronic cough 449 (55%), prostatic problems in 187 (23%), chronic constipation in 163 (20%), previous surgeries in 82 (10%), obesity in 10 (1.2%), and ascites in 9 (0.1%). Hernia surgery was performed laparoscopically in 51 (6.25%) patients. Simultaneous other surgeries were performed in 130 (16%) patients. Mortality occurred in 2 (0.24%) patients operated in emergency, and chief morbidity was due to wound infection in 25 (3%) and chronic pain in 30 (3.9%) patients.

Conclusion Abdominal wall hernias are common clinical entities. Although the pattern of presentation and management is similar, the challenges faced in a rural setup are due to ignorance, social inhibitions, and financial restraints, leading to delayed presentations which increase their morbidity and mortality. Health programs and surveys to increase awareness in rural areas as well as cutting down on expenses could help these patients.
Unnoticed Adverse Effect of Isoniazid during Childhood Tuberculosis Preventive Treatment: Hyperuricemia
Authors: Kandemir Bahar , Duman Ipek , Durduran Yasemin , Metin Akcan Ozge , Selver Muhammed Burak , Pekcan Sevgi
Published: March 2021

Objective Isoniazid for 6 to 9 months is the most widely used form of tuberculosis (TB) preventive treatment. We aimed to assess the adverse effects of isoniazid by using the serum levels of aspartate transaminase (AST), alanine transaminase (ALT), and uric acid (SUA) in children and adolescents receiving long-term isoniazid for latent TB infection.

Methods The study included children ≤18 years of age who underwent TB preventive treatment with isoniazid (IPT) between 2015 and 2019 at a university hospital. Serum transaminase, SUA, urea, and creatinine levels of patients were measured before the initiation of IPT, 15th day, and once a month during treatment. Patients with ALT, AST, or SUA results above cut-off levels during treatment were evaluated. The final values in follow-up were included in the data analysis.

Results A total of 141 children who underwent IPT were included. In total, 70 children had family members with confirmed TB disease, and 71 children had a positive tuberculin skin test. SUA increased above cut-off values in 16 children (11.3%), and half of them had uric acid levels over 7 mg/dL. The median duration of the development of hyperuricemia was 4.0 months. ALT or AST increased above cut-off values in 23 children (16.3%). ALT was above cut-off values in seven patients, AST was high in 20 patients. The median duration to the development of AST and/or ALT levels above cut-off was 4.0 months. Two patients had hepatotoxic transaminase levels. Three patients had both elevated transaminases and SUA levels.

Conclusion Isoniazid may also cause hyperuricemia besides elevation in transaminases in children.
Quality of Life after Rhinoplasty: A Prospective Study
Authors: Papadopulos Nikolaos A. , Liebmann Janina , Kloeppel Markus , Henrich Gerhard , Machens Hans-Günther , Staudenmaier Rainer , Niehaus Richard
Published: March 2021

As our previous studies have shown, cosmetic surgery has a positive correlation with postoperative well-being. The aim of this study was to prospectively examine the postoperative changes in quality of life (QoL) after a rhinoplasty. Thirty-four patients who underwent septorhinoplasty performed by a single surgeon from July 2015 to October 2018 reported in indication-specific self-developed and different validated questionnaires (FLZM or Fragen zur Lebenszufriedenheit Module, Freiburg Personality Inventor, Rosenberg self-esteem scale, Functional Rhinoplasty Outcome Inventory 17 [FROI-17], and Glasgow Benefit Inventory [GBI]) on the status of their QoL preoperatively (T0) and 6 months' follow-up (T1). Our goal was to assess the difference in psyche and self-esteem and to get objective insights into the effect of the operation. Significant improvements in QoL in terms of general module, health, and appearance were noted. The general part of the FLZM showed increasing T1 values in the sum scores (p = 0.005). With regard to the item “health,” T1 was better than the norm data (p = 0.003). The statistically significant improvement for the item nose appearance (p < 0.0001) after operation and T1 versus reference data (p < 0.010) should be highlighted. The subjective patient ratings showed statistically significant T1 improvements for all items of the FROI-17: overall nose (p < 0.0001), nasal function (p = 0.001), general/further symptoms (p = 0.006), and confidence increased by aesthetic changes (p < 0.0001). Furthermore, the GBI score shows an improved QoL after rhinoplasty (p < 0.0001). Based on the assessment of a variety of disease- and nondisease-specific validated questionnaires, numerous improvements in the QoL of the patients were observed. Therefore, we support septorhinoplasty as a meaningful procedure regarding QoL improvement. The level of evidence is Level II prospective cohort study.
Probabilistic Cauchy theory for the mass-critical fourth-order nonlinear Schrödinger equation
Authors: Dinh Van Duong
Published: March 2021

We consider the mass-critical nonlinear fourth-order Schrödinger equations with random initial data. We prove almost sure local well-posedness and probabilistic small data global well-posedness below L2-space. We also prove probabilistic blow-up for the equation with non-gauge invariance and rough random initial data.
Anti-reflection coated vacuum window for the Primordial Inflation Polarization ExploreR (PIPER) balloon-borne instrument
Authors: Datta Rahul , Chuss David T. , Eimer Joseph , Essinger-Hileman Thomas , Gandilo Natalie N. , Helson Kyle , Kogut Alan J. , Lowe Luke , Mirel Paul , Rostem Karwan , Sagliocca Marco , Sponseller Danielle , Switzer Eric R. , Taraschi Peter A. , Wollack Edward J.
Published: March 2021

Measuring the faint polarization signal of the cosmic microwave background (CMB) not only requires high optical throughput and instrument sensitivity but also control over systematic effects. Polarimetric cameras or receivers used in this setting often employ dielectric vacuum windows, filters, or lenses to appropriately prepare light for detection by cooled sensor arrays. These elements in the optical chain are typically designed to minimize reflective losses and hence improve sensitivity while minimizing potential imaging artifacts such as glint and ghosting. The Primordial Inflation Polarization ExploreR (PIPER) is a balloon-borne instrument designed to measure the polarization of the CMB radiation at the largest angular scales and characterize astrophysical dust foregrounds. PIPER’s twin telescopes and detector systems are submerged in an open-aperture liquid helium bucket dewar. A fused-silica window anti-reflection (AR) coated with polytetrafluoroethylene is installed on the vacuum cryostat that houses the cryogenic detector arrays. Light passes from the skyward portions of the telescope to the detector arrays through this window, which utilizes an indium seal to prevent superfluid helium leaks into the vacuum cryostat volume. The AR coating implemented reduces reflections from each interface to <1% compared to ∼10% from an uncoated window surface. The AR coating procedure and room temperature optical measurements of the window are presented. The indium vacuum sealing process is also described in detail, and test results characterizing its integrity to superfluid helium leaks are provided.
Collective steady-state patterns of swarmalators with finite-cutoff interaction distance
Authors: Lee Hyun Keun , Yeo Kangmo , Hong Hyunsuk
Published: March 2021

We study the steady-state patterns of population of the coupled oscillators that sync and swarm, where the interaction distances among the oscillators have a finite-cutoff in the interaction distance. We examine how the static patterns known in the infinite-cutoff are reproduced or deformed and explore a new static pattern that does not appear until a finite-cutoff is considered. All steady-state patterns of the infinite-cutoff, static sync, static async, and static phase wave are repeated in space for proper finite-cutoff ranges. Their deformation in shape and density takes place for the other finite-cutoff ranges. Bar-like phase wave states are observed, which has not been the case for the infinite-cutoff. All the patterns are investigated via numerical and theoretical analyses.
A one-parameter family of clear-sky solar irradiance models adapted for different aerosol types
Authors: Blaga Robert , Calinoiu Delia , Paulescu Marius
Published: March 2021

In this paper, a procedure for generating a family of parametrical broadband clear-sky models is described. The key element is the conversion of one or more model input variables into tunable mathematical parameters. The approach is tested on the PS model [Paulescu, M. and Schlett, Z., Theor. Appl. Climatol. 75, 203 (2003)], with the free parameter being the Ångström exponent (α). This allows us to fine-tune for conditions dominated by desert dust, urban-industrial, and mixed aerosols. We find that for an arbitrary set of data, the optimal value of the free parameter is not the same as its actual measured value (inserting the measured value in the model would result in a lower performance). We attribute this fact to the inaccurate nature of the base model. The optimal α value varies with the considered solar irradiance component, aerosol type and loading, and the error measure(s) used for assessing model accuracy. A set of recommended models for each aerosol type and loading class is given. The tabled values for the aerosol transmittance coefficients are also listed. A preliminary validation shows that the newly developed models are very reliable. The optimal version generally falls within a few percent of the results of REST2v5, a benchmark model in clear-sky solar irradiance estimation. While some established models outperform REST2v5 for certain aerosol types and for only one solar irradiance component, the new models prove competitive under most scenarios. Beyond showing the performance of the developed model family, these results hint at great potential of our approach.
Computation of host–guest binding free energies with a new quantum mechanics based mining minima algorithm
Authors: Xu Peng , Sattasathuchana Tosaporn , Guidez Emilie , Webb Simon P. , Montgomery Kilinoelani , Yasini Hussna , Pedreira Iara F. M. , Gordon Mark S.
Published: March 2021

A new method called QM-VM2 is presented that efficiently combines statistical mechanics with quantum mechanical (QM) energy potentials in order to calculate noncovalent binding free energies of host–guest systems. QM-VM2 efficiently couples the use of semi-empirical QM (SEQM) energies and geometry optimizations with an underlying molecular mechanics (MM) based conformational search, to find low SEQM energy minima, and allows for processing of these minima at higher levels of ab initio QM theory. A progressive geometry optimization scheme is introduced as a means to increase conformational sampling efficiency. The newly implemented QM-VM2 is used to compute the binding free energies of the host molecule cucurbit[7]uril and a set of 15 guest molecules. The results are presented along with comparisons to experimentally determined binding affinities. For the full set of 15 host–guest complexes, which have a range of formal charges from +1 to +3, SEQM-VM2 based binding free energies show poor correlation with experiment, whereas for the ten +1 complexes only, a significant correlation (R2 = 0.8) is achieved. SEQM-VM2 generation of conformers followed by single-point ab initio QM calculations at the dispersion corrected restricted Hartree–Fock-D3(BJ) and TPSS-D3(BJ) levels of theory, as post-processing corrections, yields a reasonable correlation with experiment for the full set of host–guest complexes (R2 = 0.6 and R2 = 0.7, respectively) and an excellent correlation for the +1 formal charge set (R2 = 1.0 and R2 = 0.9, respectively), as long as a sufficiently large basis set (triple-zeta quality) is employed. The importance of the inclusion of configurational entropy, even at the MM level, for the achievement of good correlation with experiment was demonstrated by comparing the calculated ΔE values with experiment and finding a considerably poorer correlation with experiment than for the calculated free energy ΔE − TΔS. For the complete set of host–guest systems with the range of formal charges, it was observed that the deviation of the predicted binding free energy from experiment correlates somewhat with the net charge of the systems. This observation leads to a simple empirical interpolation scheme to improve the linear regression of the full set.
Q-band high-performance notch filters at 56 and 77 GHz notches for versatile fusion plasma diagnostics
Authors: Nishiura M. , Shimizu T. , Kobayashi S. , Tokuzawa T. , Ichinose K. , Kubo S.
Published: March 2021

A six-pole Q-band waveguide filter with a notch frequency above the Q-band has been developed for plasma diagnostics. The previous paper [Nishiura et al., J. Instrum. 10, C12014 (2015)] reported that the notch frequency exists within the standard band. In this study, the newly required notch filter extends the function, which prevents a thorny wave from being mixed into an instrument beyond the standard bandwidth of the waveguide. The mode control technique for cavities realizes a deep and sharp filter shape for Q-band notch filters with 56 and 77 GHz notches, respectively. The former filter has an attenuation more than 50 dB at 56.05 GHz and a bandwidth of 1.1 GHz at −3 dB. The latter filter has an attenuation more than 55 dB at 76.95 GHz and a bandwidth of 1.6 GHz at −3 dB. The electron cyclotron emission imaging and the electron cyclotron emission (ECE) diagnostics for the Q-band implemented a pair of the fabricated filters and demonstrated the ECE measurement successfully in the intense stray radiation from a 56 GHz gyrotron.
A practically designed acoustic metamaterial sheet with two-dimensional connection of local resonators for sound insulation applications
Authors: Nakayama Masanari , Matsuoka Takeshi , Saito Yuya , Uchida Naoyuki , Inoue Kazuma , Mitani Hiroshi , Akasaka Shuichi , Koga Shogo
Published: March 2021

A novel practical design of sheet-like acoustic metamaterials is described, which comprise a two-dimensional array of mutually connected cylindrical stubs with embedded metallic weights that can be processed with a simple integral molding. We investigate the elastic wave band dispersion of the acoustic metamaterial sheets to design the connected structure of the stubs so that each stub can work as spring–mass local resonators to open the out-of-plane acoustic bandgaps. For properly integrated materials, remarkable noise insulation performance over the mass law at the resonant frequencies is experimentally demonstrated. The sound insulation mechanism is numerically analyzed in association with the sound fields, the vibrational fields, and the dynamic effective mass using the finite element method by coupling the structures with acoustics. Furthermore, we show that the insulation frequency is tunable over a wide range of frequency by designing the physical and structural parameters of the resonator. The practically designed acoustic metamaterial sheets will pave the way for industrial use of acoustic metamaterials as advanced lightweight and compact sound insulators that can be tailored to meet individual needs on problems related to noise.
Thermal performance of GaInSb quantum well lasers for silicon photonics applications
Authors: Fitch C. R. , Read G. W. , Marko I. P. , Duffy D. A. , Cerutti L. , Rodriguez J.-B. , Tournié E. , Sweeney S. J.
Published: March 2021

A key component for the realization of silicon-photonics is an integrated laser operating in the important communication band near 1.55 μm. One approach is through the use of GaSb-based alloys, which may be grown directly on silicon. In this study, silicon-compatible strained Ga0.8In0.2Sb/Al0.68In0.32Sb composite quantum well (CQW) lasers grown on GaSb substrates emitting at 1.55 μm have been developed and investigated in terms of their thermal performance. Variable temperature and high-pressure techniques were used to investigate the influence of device design on performance. These measurements show that the temperature dependence of the devices is dominated by carrier leakage from the QW region to the Xb minima of the Al0.35Ga0.65As0.03Sb0.97 barrier layers accounting for up to 43% of the threshold current at room temperature. Improvement in device performance may be possible through refinements in the CQW design, while carrier confinement may be improved by optimization of the barrier layer composition. This investigation provides valuable design insights for the monolithic integration of GaSb-based lasers on silicon.
Active control of electron cyclotron emission radiometer channel frequencies for improved electron temperature measurements
Authors: Xie R. , Houshmandyar S. , Austin M. E.
Published: March 2021

As advanced scenarios are developed for tokamak operations, the demand for flexibility of the electron cyclotron emission (ECE) channels’ locations has increased. The tunable feature of yttrium iron garnet (YIG) filters provides this spatial flexibility. Here, we present a method of performing ECE measurements on fixed flux surfaces instead of fixed frequencies. This is achieved by adjusting YIG filters utilized in the intermediate frequency section to frequencies associated with flux surfaces in regions of interest during the discharge. The key components are the application of tunable YIG filters and a control program that calculates the filter settings using flux information from real-time reconstruction equilibria (EFIT). This fast procedure facilitates Te measurements in regions of interest to investigate plasma dynamic behaviors.
Dynamics of the ground layer communities of tropical eucalypt woodlands of northern Queensland
Authors: Neldner V. J. , Butler D. W.
Published: March 2021

This paper presents insights from long-term monitoring into the dynamics of savanna plant species composition, specifically on the ground layer. Key questions are (1) how much variation is there from year to year in plant species abundance and composition? And (2) is there evidence of directional change in community composition? Five sites were located near Mareeba, north-eastern Australia, and sampled 18 times with fixed 500-m2 plots at the annual peak of plant species richness over 23 years. The sites were located in eucalypt communities across an altitudinal range of 460 m. Sampling involved systematic searching of all plant species visible above ground. The results show variation from year to year among satellite herbaceous species, with more than 50% of grasses and forbs observed at a given site only being detected at half or fewer of the 18 samplings. Herbaceous composition did not show clear signs of directional change relative to inter-annual variability. Over the 23 years, there were three very dry periods and 4 very wet years. Rainfall variation affected total cover more than plant species composition or richness. Several fires and episodes of grazing affected ground cover but did not have a lasting impact on cover or diversity. The cover and composition of the ground layer is consistently dominated by the core perennial grasses Themeda triandra Forssk. and Heteropogon triticeus (R.Br.) Stapf, with many species collectively contributing minimally to the overall cover but significantly to richness. Many herb species are persistent long-lived perennials which do not appear above ground every year. The number of naturalised plants in the ground layer was consistently low. Overall, the ground layer communities appear to be very stable in these woodlands that have been burnt 3–5 times in 23 years. High inter-annual variability of subdominant species is consistent with other studies, and emphasises the need for replication in time in ecological sampling.
Zn
2+
influx activates ERK and Akt signaling pathways
Authors: Anson Kelsie J. , Corbet Giulia A. , Palmer Amy E.
Published: March 2021

Significance

While zinc (Zn
2+
) is a vital ion for cell function and human health, little is known about the role it plays in regulating cell signaling. Here, we use fluorescent tools to study the interaction between Zn
2+
and cell signaling pathways that play a role in cell growth and proliferation. Importantly, we use small, non-toxic Zn
2+
concentrations to ensure that our Zn
2+
changes are closer to what cells would experience in the body and not stress inducing. We also demonstrate that these signaling changes are driven by Ras activation, which contradicts one of the major hypotheses in the field. Our sensors shed light on how cells respond to an important micronutrient in real time.
Comparative structural analysis of human Na
v
1.1 and Na
v
1.5 reveals mutational hotspots for sodium channelopathies
Authors: Pan Xiaojing , Li Zhangqiang , Jin Xueqin , Zhao Yanyu , Huang Gaoxingyu , Huang Xiaoshuang , Shen Zilin , Cao Yong , Dong Mengqiu , Lei Jianlin , Yan Nieng
Published: March 2021

Significance

Na
v
1.1 is a major Na
v
subtype in the brain. Up to 900 nonsense and missense mutations in
SCN1A
, the coding gene for Na
v
1.1, have been identified in patients with epilepsy syndromes. Here, we report the cryo-EM structure of the human Na
v
1.1–β4 complex. Comparative structural analysis of hundreds of missense disease mutations in Na
v
1.1 and Na
v
1.5, whose structure is reported in the accompanying paper, reveals 70 loci that are common in these two channels. Several clusters, defined as the mutational hotspots, are identified and generally classified as the structural mutations and functional mutations. Our comparative structural analyses establish a framework for structure–function relationship dissection of Na
v
disease variants and will facilitate development of precision medicine for various sodium channelopathies.
At Risk of What? Understanding Forensic Psychiatric Inpatient Aggression through a Violence Risk Scenario Planning Lens
Authors: Gatner Dylan T. , Moulden Heather M. , Mamak Mini , Chaimowitz Gary A.
Published: March 2021

Violence risk assessment is an essential component of forensic mental health services designed to help mitigate and manage the re-occurrence of violence. Although there is large body of evidence supporting structured risk assessments, there is no empirical evidence regarding scenario planning—a specific component of the structured professional judgment approach to violence risk assessment. The purpose of this study was to investigate the base rates and concurrent validity of inpatient aggression scenarios to provide information about risk scenarios. Among a large representative sample of forensic psychiatric patients ( N = 1240), the prevalence of risk scenarios ( Repeat, Escalation, Twist, and Improvement scenarios) was investigated by retrospectively coding changes in inpatient aggression. The results suggested that Improvement scenarios, including a continued desistance of aggression, were common. Aggression scenarios shared significant pattern of associations with the Historical-Clinical-Risk Management-20 and the Psychopathy Checklist—Revised. Overall, this study presents initial empirical evidence related to violence risk scenario planning. Implications from these findings include how scenario planning may intersect with evaluator bias in forensic mental health assessments.
SPHINCS_BSSN: a general relativistic smooth particle hydrodynamics code for dynamical spacetimes
Authors: Rosswog S , Diener P
Published: March 2021

We present a new methodology for simulating self-gravitating general-relativistic fluids. In our approach the fluid is modelled by means of Lagrangian particles in the framework of a general-relativistic (GR) smoothed particle hydrodynamics (SPH) formulation, while the spacetime is evolved on a mesh according to the Baumgarte–Shapiro–Shibata–Nakamura (BSSN) formulation that is also frequently used in Eulerian GR-hydrodynamics. To the best of our knowledge this is the first Lagrangian fully general relativistic hydrodynamics code (all previous SPH approaches used approximations to GR-gravity). A core ingredient of our particle–mesh approach is the coupling between the gas (represented by particles) and the spacetime (represented by a mesh) for which we have developed a set of sophisticated interpolation tools that are inspired by other particle–mesh approaches, in particular by vortex-particle methods. One advantage of splitting the methodology between matter and spacetime is that it gives us more freedom in choosing the resolution, so that—if the spacetime is smooth enough—we obtain good results already with a moderate number of grid cells and can focus the computational effort on the simulation of the matter. Further advantages of our approach are the ease with which ejecta can be tracked and the fact that the neutron star surface remains well-behaved and does not need any particular treatment. In the hydrodynamics part of the code we use a number of techniques that are new to SPH, such as reconstruction, slope limiting and steering dissipation by monitoring entropy conservation. We describe here in detail the employed numerical methods and demonstrate the code performance in a number of benchmark problems ranging from shock tube tests, over Cowling approximations to the fully dynamical evolution of neutron stars in self-consistently evolved spacetimes.
How to get from static to dynamic electromagnetism
Authors: König Jürgen
Published: March 2021

We demonstrate how to derive Maxwell’s equations, including Faraday’s law and Maxwell’s correction to Ampère’s law, by generalizing the description of static electromagnetism to dynamical situations. Thereby, Faraday’s law is introduced as a consequence of the relativity principle rather than an experimental fact, in contrast to the historical course and common textbook presentations. As a by-product, this procedure yields explicit expressions for the infinitesimal Lorentz and, upon integration, the finite Lorentz transformation. The proposed approach helps to elucidate the relation between Galilei and Lorentz transformations and provides an alternative derivation of the Lorentz transformation without explicitly referring to the speed of light.
Modular elastic metasurfaces with mass oscillators for transmitted flexural wave manipulation
Authors: Lin Zibin , Xu Weikai , Xuan Chengming , Qi Wuchao , Wang Wei
Published: March 2021

In the present study, a modular mass oscillator elastic metasurface (MMEM) is proposed to manipulate the wavefield of flexural waves by assembling and replacing mass-oscillator-like functional units. Based on the bandgap analysis of phononic crystals, the MMEMs were found to achieve a full

2
π

range of phase shift with relatively high transmission using functional unit arrangements of varying sizes (masses). According to the generalized Snell’s law, the modulation of abnormal refraction, lens focusing, and beam self-acceleration can be realized. To broaden the operating frequency domain, we present the idea of a multiple mass oscillator array design, which can control flexural waves at broadband frequencies of 13–41 kHz by adding/removing mass oscillators within a functional unit. This study presents a method to realize tunable metasurfaces and provides an innovative concept for broadening the operating frequency of elastic metasurfaces.
Quantify the combined effects of temperature and force on the stability of DNA hairpin
Authors: Li Lin , Wang Hongchang , Xiong Caiyun , Luo Di , Chen Hu , Liu Yanhui
Published: March 2021

OxDNA, as a successful coarse-grain model, has been applied to reproduce the thermodynamic and mechanical properties of both single- and double-stranded DNA. In current simulation, oxDNA is extended to explore the combined effects of temperature and force on the stability of DNA hairpin and its free energy landscape. Simulations were carried out at different forces and temperatures, at each temperature, a 18-base-pair DNA hairpin dynamically transited between folded state and unfolded state, and the separation between two states is consistent with the full contour length of single-stranded DNA in the unfolded state. Two methods were used to identify the critical force of DNA hairpin at each temperature and the critical forces obtained from two methods were consistent with each other and gradually decreased with the increasing temperature from 300 K to 326 K. The critical force at 300 K is reasonably consistent with the single molecule result of DNA hairpin with the same stem length. The two-state free energy landscape can be elucidated from the probability distribution of DNA hairpin extension and its dependence on the force and temperature is totally different. The increasing temperature not only reduces the free energy barrier, but also alters the position of transition point along the extension coordinate, resulting in the reduction of folding distance and the extension of unfolding distance, but their sum is not obviously dependent on the temperature. Generally, an assumption that the location of transition state in two-state energy landscape is independent of the stretching force is used to analyze the data of the single molecule experiment, but current simulation results indicate that effects of stretching forces on the location of transition state in two-state energy landscape are dependent on temperature. At relatively high temperature, stretching force can also change the location of transition state in the free energy landscape.
Asymmetry in the propagation of vortex domain wall artificial skyrmion composite system
Authors: Eilmsteiner D , Wang Xi-guang , Chotorlishvili L , Paischer S , Hoffmann M , Buczek P , Ernst A
Published: March 2021

We studied the propagation of an artificial skyrmion coupled to the vortex domain wall (VDW). We discovered the following effect: depending on the propagation’s direction, the dynamics of the coupled skyrmion VDW can be faster than the isolated VDW’s velocity. The reason for such behavior is the structural distortion that occurs in the coupled system. We interpret the numerical results in terms of the modified Thiele’s equation. In particular, increasing the Thiele’s equation counteractive coefficient leads to the perfect fitting with the micromagnetic simulation results.
Longitudinal magnetoconductivity of tilted type-I Weyl semimetals from semiclassical to ultra-quantum regime
Authors: Shao Jianmei , Yan Lijuan
Published: March 2021

Weyl semimetals (WSMs) display many unusual magnetotransport phenomena. Here, based on the Landau quantization and Boltzmann equation, we theoretically study the longitudinal magnetoconductivity for tilted type-I WSMs from weak to strong magnetic field within a unified framework. It is found that, in semiclassical (weak magnetic field) regime, the conductivity has an angular dependent B-linear term besides the B-quadratic term common to isotropic nodes. In ultra-quantum (strong magnetic field) regime, the magnetoconductivity shows a linear dependence on B, and this dependence is affected by the tilt. In the intermediate regime, magnetoconductivity shows a tilt-modified quantum oscillation behavior due to the oscillation in the density of state. These findings recover the results for isotropic nodes without tilt, and suggest a possible way to identify the tilt axis of tilted WSMs through magnetotransport experiment.
Design, construction and traceable calibration of a phosphor-based fibre-optic thermometer from 0 °C to 650 °C
Authors: Lowe D , Sutton G , Sposito A , Machin G , Pearce J
Published: March 2021

Measurement traceability, in which there is a documented chain of calibration links from a measurement back to a primary realisation of a unit, is vital for achieving the smallest uncertainty in metrology. A sensor that can provide a traceable link in harsh environments may be advantageous even if its uncertainty is larger than that of typical calibrated devices. A phosphor-based thermometer that has optical rather than electrical connections has been built and then calibrated in terms of the International Temperature Scale of 1990. Its standard uncertainty ranges from 0.5 °C at 0 °C to 2 °C at 650 °C. While this uncertainty cannot match what is possible with thermocouples or resistance thermometers, the optical basis of the sensor means it can be used in situations where electrical connections are precluded.
Mechanics of penta-graphene with vacancy defects under large amplitude tensile and shear loading
Authors: Han Tongwei , Wang Xueyi , Zhang Xiaoyan , Scarpa Fabrizio , Tang Chun
Published: March 2021

Penta-graphene is a new two-dimensional metastable carbon allotrope composed entirely of carbon pentagons with unique electronic and mechanical properties. In this work we evaluate the mechanical properties of new classes of defective penta-graphene (DPG) subjected to tensile and shear loading by using molecular dynamics simulations. The types of defects considered here are monovacancy at either 4-coordinated C1 site or 3-coordinated C2 site, and double vacancy (DV). We focus in particular on the effects of the different topologies of defects and their concentrations on the elastic constants and the nonlinear mechanics of this allotropic form of carbon. The results indicate that DPG has a plastic behavior similar to pristine penta-graphene, which is caused by the irreversible pentagon-to-polygon structural transformation occurring during tensile and shear loading. The tensile and shear moduli decrease linearly with the concentration of defects. Monotonic reductions of the tensile yield and shear stresses are also present but less pronounced, while the yield strains are unaffected. Penta-graphene with 4-coordinated and DVs feature a change of the Poisson’s ratio from negative to positive when the defect concentration rises to about 3% and 6%. Temperature can trigger structural reconstruction for free-standing DPG. The critical transition temperature increases due to the vacancy defects and the defects can delay the structure transition. These findings are expected to provide important guidelines for the practical applications of penta-graphene based micro/nano electromechanical systems.
Direct determination of complex amplitude of arbitrary ultrashort pulses via spectral phase conjugation
Authors: Lam Billy , Guo Chunlei
Published: March 2021

Unambiguous determination of the electric field of arbitrary ultrashort pulses is the key for time and frequency standards, attosecond science, and precision spectroscopy. However, a single-step technique that can simultaneously and directly characterize the spectrum, spectral phase, and the carrier-envelope phase (CEP) information of an arbitrary ultrashort pulse remains elusive. This technological roadblock hinders the current field from studying non-repeating single-shot events, since ultrashort laser pulses are often unstable. Here, we introduce a single-step reference-free technique through polarization interfering electric field with phase inverted electric field (PIE-PIE) to directly measure arbitrary ultrashort pulses in single-shot operation without using any retrieval algorithm. PIE-PIE utilizes highly efficient spectral phase conjugation based on four-wave-mixing. The ability to fully determine the spectrum, spectral phase, and CEP of relatively low intensity single-shot pulses will revolutionize ultrafast sciences and enable studies of arbitrary non-repeating ultrafast events.