bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Fetal Cardiac Output and Modified Myocardial
Performance Index in Pregnant Women with Idiopathic Polyhydramnios: A Case
Control Study from a Tertiary Hospital
Authors: Sakcak Bedri , Denizli Ramazan , Farisoğulları Nihat , Haksever Murat , Turgut Ezgi , Kara Ozgur , Tanacan Atakan , Sahin Dilek
Published: July 2023

Purpose This study aimed to investigate fetal cardiac output and
myocardial performance index in pregnant women with idiopathic polyhydramnios
and compare them to healthy pregnant women.

Methods Thirty patients admitted to Ankara City Hospital at 24–39
weeks of gestation with idiopathic polyhydramnios were included as the study
group. Clinical characteristics, fetal cardiac output, and fetal modified
myocardial performance index (Mod-MPI) were compared between the groups.

Results The combined cardiac output (CCO), left cardiac output (LCO),
right cardiac output (RCO), pulmonary artery velocity time integral (PA-VTI),
and aortic VTI were statistically significantly higher in the study group
(p=0.003, p=0.028, p=0.002, p=0.000, and
p=0.017, respectively).The idiopathic polyhydramnios group had a
significantly higher Mod-MPI and isovolumetric contraction time (ICT) and a
significantly lower ejection time (ET) compared to the controls (p=000,
p=0.003, and p=0.023, respectively). In the idiopathic
polyhydramnios group, the aortic max (p=0.009) and aortic VTI
(p=0.047) values were significantly lower and the left ventricular
outflow tract isovolumetric relaxation time (LVOT-IRT) (p=0.021) was
significantly higher in cases where the NICU was required. According to the ROC
analysis performed in the idiopathic polyhydramnios group, the optimal cut-off
values of aortic max, aortic VTI, and LVOT-IRT in the prediction of the NICU
requirement were (57.5, 0.089 and 41.5, respective cut-off value)
(p=0.010, p=0.048, p=0.021, respectively).

Conclusions Both fetal cardiac output and Mod-MPI values were altered in
fetuses with idiopathic polyhydramnios.
Long-Term Recurrence Rates and Patient Satisfaction after Repair of Pectus Excavatum
Authors: Cruz-Centeno Nelimar , Fraser James A. , Stewart Shai , Marlor Derek R. , Oyetunji Tolulope A. , St Peter Shawn D.
Published: July 2023

Background Pectus excavatum deformities are usually repaired with a minimally invasive approach in which a metal bar is used to correct the chest wall abnormality. We aimed to evaluate long-term outcomes and patient satisfaction after surgical correction.

Methods Patients who underwent pectus excavatum repair and subsequent bar removal at a single tertiary care center from January 2000 to December 2020 were identified. A retrospective chart review was performed, and a telephone survey was conducted to evaluate perceived inward chest movement, need for surgeon reevaluation, surgical reintervention, and overall satisfaction. Data are presented as medians with interquartile ranges (IQRs) and frequencies with percentages.

Results A total of 583 patients were included. The survey response rate was 26.2% (n = 153). The respondents were predominantly male (80.4%, n = 123) with a median age at surgical correction of 14.9 years (IQR 12.9, 16.1) and a median Haller index (HI) of 3.8 (IQR 3.4, 4.5). Median time to bar removal was 2.9 years (IQR 2.5, 3.0) with a median age at removal of 17.7 years (IQR 15.5, 19.0). Median time from surgery to survey follow-up was 9.6 years (IRQ 5.0, 11.4) with respondents having a median age at follow-up of 25 years (IQR 22.0, 28.4). The satisfaction rate was 96.7% (n = 148) with a reintervention rate of 2.0% (n = 3). The perceived inward chest movement was 30.7% (n = 47) with 12.8% (n = 6) of those requesting surgical reevaluation.

Conclusion There is a high level of satisfaction many years after correction of pectus excavatum and bar removal. With the advent of cryoablative therapy since 2017, patient satisfaction improved by experience of less postoperative pain. Reintervention rate is low despite some patients reporting a perceived chest wall inward movement.
Texture and color enhancement imaging versus high definition white-light endoscopy for detection of colorectal neoplasia: a randomized trial
Authors: Antonelli Giulio , Bevivino Gerolamo , Pecere Silvia , Ebigbo Alanna , Cereatti Fabrizio , Akizue Naoki , Di Fonzo Michela , Coppola Manuela , Barbaro Federico , Walter Benjamin M. , Sharma Paranjay , Caruso Anna , Okimoto Kenichiro , Antenucci Claudia , Matsumura Tomoaki , Zerboni Giulia , Grossi Cristina , Meinikheim Michael , Papparella Luigi Giovanni , Correale Loredana , Costamagna Guido , Repici Alessandro , Spada Cristiano , Messmann Helmut , Hassan Cesare , Iacopini Federico
Published: July 2023

Background Texture and color enhancement imaging (TXI) was recently proposed as a substitute for standard high definition white-light imaging (WLI) to increase lesion detection during colonoscopy. This international, multicenter randomized trial assessed the efficacy of TXI in detection of colorectal neoplasia.

Methods Consecutive patients aged ≥ 40 years undergoing screening, surveillance, or diagnostic colonoscopies at five centers (Italy, Germany, Japan) between September 2021 and May 2022 were enrolled. Patients were randomly assigned (1:1) to TXI or WLI. Primary outcome was adenoma detection rate (ADR). Secondary outcomes were adenomas per colonoscopy (APC) and withdrawal time. Relative risks (RRs) adjusted for age, sex, and colonoscopy indication were calculated.

Results We enrolled 747 patients (mean age 62.3 [SD 9.5] years, 50.2 % male). ADR was significantly higher with TXI (221/375, 58.9 %) vs. WLI (159/372, 42.7 %; adjusted RR 1.38 [95 %CI 1.20–1.59]). This was significant for ≤ 5 mm (RR 1.42 [1.16–1.73]) and 6–9 mm (RR 1.36 [1.01–1.83]) adenomas. A higher proportion of polypoid (151/375 [40.3 %] vs. 104/372 [28.0 %]; RR 1.43 [1.17–1.75]) and nonpolypoid (136/375 [36.3 %] vs. 102/372 [27.4 %]; RR 1.30 [1.05–1.61]) adenomas, and proximal (143/375 [38.1 %] vs. 111/372 [29.8 %]; RR 1.28 [1.05–1.57]) and distal (144/375 [38.4 %] vs. 98/372 [26.3 %]; RR 1.46 [1.18–1.80]) lesions were found with TXI. APC was higher with TXI (1.36 [SD 1.79] vs. 0.89 [SD 1.35]; incident rate ratio 1.53 [1.25–1.88]).

Conclusions TXI increased ADR and APC among patients undergoing colonoscopy for various indications. TXI increased detection of polyps < 10 mm, both in the proximal and distal colon, and may help to improve colonoscopy quality indicators.
Exclusive Breastfeeding in the Bronx—Successes and Shortcomings
Authors: Grande Julia , Liu Jianyou , Nemerofsky Sheri
Published: July 2023

Objective Despite efforts to encourage breastfeeding, exclusive breastfeeding (EBF) rates in the Bronx remain suboptimal. Hospital restrictions and uncertainty surrounding the side effects of coronavirus disease 2019 (COVID-19) greatly impacted the mother–infant dyad during the postpartum hospitalization. Preliminary studies found an initial decrease in EBF, but lasting effects remain unknown. This study aimed to investigate the effect of the COVID-19 pandemic on birth hospitalization EBF rates among a high-risk urban patient population.

Study Design A retrospective chart review was conducted on all newborns admitted to the newborn nursery at an urban medical center between 2019 and 2021. Patients were separated into prepandemic and pandemic cohorts. Patient demographics, maternal comorbidities, length of stay, feeding method, and newborn characteristics, including status as high risk for hypoglycemia, were collected. EBF was defined as receiving only mother's milk during the birth hospitalization. Descriptive statistics and bivariate analysis were used to examine the data.

Results A total of 630 prepandemic and 643 pandemic newborns were included. The cohorts did not differ in baseline maternal characteristics. Prepandemic newborns were less likely to be high risk (23.3 vs. 29.4%, p = 0.01), more likely to see the hospital lactation consultant (53.2 vs. 24.0%, p < 0.001), and had a longer average length of stay (63.4 vs. 54.5 hours, p < 0.001). Most infants in both cohorts received some breastmilk during the hospitalization (97.6 vs. 94.6%, not significant). There was no difference in EBF between cohorts among all newborns (9.5 vs. 11.4%, p = 0.29) or among nonhigh-risk newborns (12.2 vs. 15.0%, p = 0.22).

Conclusion EBF rates in the Bronx, NY did not change during the pandemic period, despite an increase in high-risk newborns. Further investigation into the effect of lactation consultation, maternal race, ethnicity, and primary language should be further explored to understand the implications of health care disparities on the mother–infant dyad.

Key Points
The role of networks in international acquisition premiums
Authors: Li Chengguang , Luo Yadong , Bu Juan , Tang Yinuo
Published: July 2023

Our work builds on network theory to investigate the role of alliance networks in international acquisition premiums. On the one hand, we postulate that an international acquirer’s network centrality in the target country lowers the inclination of offering higher bid premiums associated with its liability of foreignness (i.e., negatively moderates the relation between foreignness and premiums). On the other hand, we provide a perspective that a target firm’s local network centrality increases an international acquirer’s willingness to pay higher premiums in order to gain access to unique and valuable local knowledge and resources (i.e., positively moderates the relationship between foreignness and premiums). To test our hypotheses, we analyzed a sample of 1693 related acquisition bids made in more than 40 countries between 2008 and 2017. Our findings support our dual perspective on the role of networks and demonstrate that the acquirer's networks and the target's networks have distinct influences on the relationship between foreignness and bid premiums. This study makes contributions to the understanding of the complex dynamics at play in international M&As and emphasizes the importance of distinguishing between the acquirer’s and the target’s networks in shaping acquisition premiums.
Global existence and time-decay rates of solutions to the generalized Boussinesq equation with weak damping
Authors: Wang Yinxia , Luo Zehua , Li Dan
Published: July 2023

In this paper, we study the initial value problem for the generalized Boussineq equation with weak damping. The existence and time-decay rates of global solutions and its derivatives are established for all space dimensions d ≥ 1, provided that the norm of the initial data is suitably small. The negative Sobolev norms of the initial data in low frequency are shown to be preserved along time evolution and enhance the decay rates of global solutions. The proof is based on the energy method and flexible interpolation trick without investigating the corresponding linear equation.
Improvement of image-type very-low-energy-electron-diffraction spin polarimeter
Authors: Zha Heming , Liu Wenjing , Wang Deyang , Zhao Bo , Shen Xiaoping , Ye Mao , Qiao Shan
Published: July 2023

Spin- and angle-resolved photoemission spectroscopy (SARPES) with high efficiency and resolution plays a crucial role in exploring the fine spin-resolved band structures of quantum materials. Here, we report the performance of the SARPES instrument with a second-generation home-made multichannel very-low-energy-electron-diffraction spin polarimeter. Its energy and angular resolutions achieve 7.2 meV and 0.52°, respectively. We present the results of SARPES measurements of Bi(111) film to demonstrate its performance. Combined with the density functional theory calculations, the spin polarization of the bulk states was confirmed by the spin-layer locking caused by the local inversion asymmetry. The surface states at a binding energy of 0.77 eV are found with 1.0 ± 0.11 spin polarization. Better resolutions and stability compared with the first-generation one provide a good platform to investigate the spin-polarized electronic states in materials.
Same-sided successive-shock HED instability experiments
Authors: Merritt E. C. , Doss F. W. , Stefano C. A. Di , Sacks R. F. , Rasmus A. M. , Levesque J. M. , Flippo K. A. , Robey H. , Schmidt D. W. , Christiansen N. S. , Millot M. , Kot L. , Perry T. , Meyerhofer D. D.
Published: July 2023

Inertial confinement fusion (ICF) and high-energy density (HED) physics experiments experience complicated forcing for instability growth and mix due to the ubiquitous presence of multiple shocks interacting with perturbations on multiple material interfaces. One common driver of instability growth is successive shocks from the same direction. However, there is a severe lack of analytic work and modeling validation for same-sided successive shocks since they are extremely difficult to achieve with conventional (non-HED) drivers. Successive shocks access a large instability parameter space; idealized fluid theory [K. O. Mikaelian, Phys. Rev. A 31, 410 (1985)] predicts 15 different interface evolution scenarios for a sinusoidal perturbation. Growth becomes more complex for multi-mode, compressible HED systems. The Mshock campaign is the first experiment in any fluid regime to probe a wide portion of successive shock parameter space. This is enabled by our development of a hybrid direct/indirect drive platform capable of creating independently controllable successive shocks on the National Ignition Facility. These experiments have delivered the first data capable of rigorously challenging our models and their ability to accurately capture Richtmyer–Meshkov growth under successive shocks. Single-mode and two-mode experiments have successfully demonstrated the ability to access and control the various growth scenarios of the shocked interface, including re-inversion, freeze out, and continued growth. Simulations and theoretical modeling are shown to accurately capture the experimental observations in the linear growth phase, giving us confidence in our ICF/HED design codes.
High precision control of laser energy for laser–matter interaction studies
Authors: Wang Xiaoming , Zhang Jun , Sethian John
Published: July 2023

Precise, highly reproducible control of the laser energy is required for high confidence laser–matter interaction research such as in dynamic compression science and high energy density physics. The energy must be adjustable without affecting the pulse shape (time varying intensity) or beam smoothness. We have developed a convenient two-stage energy tuning method for a nominal 100 J, 351 nm (UV) laser. The energy is adjusted in 10 J (10%) increments by operating the laser at full energy and inserting a beam splitter in the laser output. As the splitter is located after the final frequency tripling optics, the UV pulse shape is unchanged. The energy is varied by substituting a splitter of different reflectivity. For finer 3 J (3%) increments, the infrared pulse is attenuated inside the laser before the final amplifier. This requires modest tuning to preserve the pulse shape. The demonstrated variation in shot-to-shot reproducibility is less than +/−2.5 J (5% of the full energy), irrespective of the laser output energy. These approaches can be adapted to most ∼100 J class lasers. We describe these techniques and show two examples where they have elucidated the underlying physics in laser shock compression experiments. One used only the beam splitters to establish the pressure for melting in iron. The other combined both techniques to finely increment the peak stress (∼2 GPa steps) in germanium to precisely determine the onset and completion of melting—including the melting kinetics. These unambiguous results would not be possible without the developments described here.
Realize low-power artificial photonic synapse based on (Al,Ga)N nanowire/graphene heterojunction for neuromorphic computing
Authors: Zhou Min , Zhao Yukun , Gu Xiushuo , Zhang Qianyi , Zhang Jianya , Jiang Min , Lu Shulong
Published: July 2023

The fast development of brain-inspired neuromorphic computing systems has stimulated urgent requirements for artificial synapses with low-power consumption. In this work, a photonic synaptic device based on (Al,Ga)N nanowire/graphene heterojunction has been proposed and demonstrated successfully. In the artificial synaptic device, the incident light, the nanowire/graphene heterojunction, and the light-generated carriers play the roles of action potential, pre-synaptic/post-synaptic membrane, and neurotransmitter in a biological synapse, respectively. As a key synaptic function, the paired pulse facilitation index of the photonic synapse can reach 202%, which can be modulated by the interval time between two adjacent light pulses. It is found that the graphene defects, the surface band bending, and the Al vacancies on the surface of (Al,Ga)N nanowires can be the key reasons contributing to the synaptic characteristics of artificial photonic devices. Hence, the dynamic “learning–forgetting” performance of the artificial synaptic device can resemble the “learning–forgetting” behavior of the human brain. Furthermore, the hand-written digits are set up to mimic a typical characteristic of human perceptual learning. After only three training epochs, the simulated network can achieve a high recognition rate of over 90% based on the experimental conductance for long-term potentiation and long-term depression. In supervised learning processes, such few training times are beneficial to reduce energy consumption significantly. Therefore, in the area of neuromorphic computing technology and artificial intelligence systems requiring low-power consumption, this work paves a potential way to develop the optoelectronic synapse based on semiconductor nanowires.
Design and fabrication of nanometer measurement platform for better understanding of silicon mechanical properties
Authors: Haras Maciej , Robillard Jean-François , Skotnicki Thomas , Dubois Emmanuel
Published: July 2023

Semiconductor industry is experiencing unprecedented growth, still driven by Moore's law, which is continually delivering devices with improved performance at lower costs. The continuation of this development places the industry in a divergent trade-off between economic attractiveness, technological feasibility, and the need for further performance improvement. Since the mainstream semiconductor technologies are silicon-based, new disruptive innovations are needed to gain additional performance margins. The use of nanowires is the preferred approach for preserving electrostatic control in the MOS transistor channel, and the application of mechanical stress is a booster of carrier mobility. It is in this context that this paper presents the design, fabrication, theoretical modeling, and characterization of a measurement platform to characterize the mechanical tensile stress of extremely narrow Si nanowires as small as 14.2 ± 1.12 nm in width. The proposed measurement platform enables a precise control of uniaxial strain, in terms of both amplitude and location, through the implementation of a stoichiometric Si3N4 pulling strand exerting a high tensile force on silicon nanowires. Reported devices are fabricated using a silicon-on-insulator wafer with fully complementary metal–oxide–semiconductor-compatible processing and top-down approach. It is observed that the mechanical strength of nanostructured Si is size-dependent and increases with miniaturization. Characterization revealed a record tensile strength value of 7.53 ± 0.8% (12.73 ± 1.35 GPa) for the narrowest nanowires fabricated using a top-down approach.
Spalling induced van der Waals lift-off and transfer of 4-in. GaN epitaxial films
Authors: Snure Michael , Blanton Eric W. , Soukhoveev Vitali , Vogt Timothy , Osinsky Andrei , Prusnick Timothy , Kennedy W. Joshua , Glavin Nicholas R.
Published: July 2023

Epitaxial lift-off (ELO) of high-quality GaN layers allows for integration with a variety of materials enabling improved performance, reduced costs, and development of new electronics. Of the ELO technologies, two-dimensional (2D) material-based lift-off offers great promise but is still in the early stages of development and has yet to demonstrate the scale and yield of other ELO technologies. Here, we demonstrate the potential of this process's scalability, speed, and yield through epitaxial growth and lift-off of 4-in. GaN films using a 2D boron nitride (BN) van der Waals (vdW) buffer layer. Since the BN layer acts as the growth template and the mechanical release layer, both the quality and adhesion of the GaN layer are correlated with the BN morphology and uniformity. Detailed spectroscopic mapping demonstrates excellent BN uniformity, which translates into growth of high-quality GaN as shown in mapping of the x-ray rock curves (XRCs), atomic force microscopy, and photoluminescence. Scanning transmission electron microscopy and electron energy loss spectroscopy reveal abrupt chemically distinct interfaces between the sapphire, BN, and AlN/GaN layers essential for efficient lift-off. Combined with the BN/GaN vdW heterostructure, Ni spalling is used to efficiently lift-off and transfer a full 4-in. GaN layer. Post transfer characterization of a 1.9 μm thick GaN layer transferred to a SiO2/Si wafer shows a very minimal change in the XRC and photoluminescence. Strain measurements before and after transfer show that the process fully relaxes residual strain formed in the GaN during high-temperature growth. This work highlights the potential for industry scalability of an exciting 2D material-based lift-off technology, which can facilitate higher power and more efficient radio frequency devices.
The thermo-aerodynamic performance of turbulent channel flow over dimples of different sizes
Authors: Nasr M. A. , Tay C. M. , Khoo B. C.
Published: July 2023

Dimples were introduced as a passive method for heat transfer enhancement and a potential drag reduction tool. However, besides the flow parameters, dimples have several design parameters that control their thermal and dynamic performance. To find the optimal design to improve dimples' performance, each parameter's effect has to be investigated. In this study, we show the effect of different dimples' sizes and flow Reynolds numbers on heat transfer and drag performance of a turbulent channel flow. Wall-resolved Large Eddy Simulation has been used to simulate the flow over the dimples fitted only on the bottom wall of the channel. The flow is simulated over three different sizes with dimensionless diameters D+=2.5, 4π/3, and 5 along with three different friction Reynolds numbers Reτ ≅180, 395, and 590. The dimples are arranged in a staggered form with smooth rounded edges of radius equal to half dimple's base radius along with constant maximum allowable coverage ratio and depth-to-diameter ratio of 5%. The thermo-aerodynamic performance of the cases under study shows an increase in drag for all the cases but accompanied by heat transfer enhancement. The thermo-aerodynamic efficiency, represented in area and volume goodness factors, shows an increase up to around 2%, and 6.8% compared to the flat channel, respectively, with the area goodness factor to be affected by the dimple size more than Reynolds number.
Self-driven thermoelectric cooling contraption for liquid metals under the static magnetic field
Authors: Zhang Dengke , Wang Zenghui , Meng Xu , Cai Zhiyang , Chen Zhaoqi
Published: July 2023

The presence of large temperature gradients in liquid metals during heat transfer can also induce thermoelectric effects, which can lead to pumping or stirring of liquid metals under the action of magnetic fields. The thermoelectric effect of liquid metals has potential application background in both nuclear fusion and metal metallurgy. In this paper, an experimental study of flow driven by the Seebeck effect, in which the temperature-dependent voltage difference at an interface between dissimilar metals, in the presence of a magnetic field, can be used to create a Lorentz force. It is proposed that this method could be used for cooling electronics, fusion reactors, and solar technologies. The working fluid is eutectic gallium–indium–tin, and flow measurements are made with ultrasound. The flow velocity tends to increase and then decrease as the magnetic field increases. Two scaling relations are developed to predict the velocity, one for weak magnetic fields and one for strong magnetic fields. Those predictions are combined to estimate the maximum velocity. Temperature gradients and wall conductance ratio have a significant effect on the Seebeck effect self-driven flow. It is found that the self-driven flow velocity caused by the Seebeck effect is positively correlated with the number of channels in the multi-channel experiments. This design idea of self-generated flow and heat transfer of liquid metal in the magnetic field will provide the possibility of pumpless self-driven liquid lithium flow in nuclear fusion reactors and provide new ideas for cooling of electronic products and related energy-saving and emission reduction applications.
Statistical fluid mechanics: Dynamics equations and linear response theory
Authors: Peng Haibing
Published: July 2023

The statistical nature of discrete fluid molecules with random thermal motion so far has not been considered in mainstream fluid mechanics based on Navier–Stokes equations, wherein fluids have been treated as a continuum breaking into many macroscopically infinitely small (but microscopically large enough) mass elements with their motion only characterized by center-of-mass velocity. Here, we provide a Statistical Mechanical approach to address fluid dynamics by considering statistical velocity distribution of discrete molecules within macroscopically infinitely small volume elements as well as their center-of-mass velocity. Dynamics equations governing the evolution of physical variables have been proposed, Green's functions have been obtained, and the linear response theory has been applied to study physical situations with external heat perturbation. It is found that the propagation of heat, center-of-mass motion, and sound are intrinsically integrated in Statistical fluid dynamics. This work lays down the foundation for applications of Statistical fluid mechanics.
Vortex dynamics and flow-induced vibration of a rounded-square cylinder with a detached splitter plate
Authors: Mittal Charu , Abhishek  , Sharma Atul
Published: July 2023

For flow-induced vibration of a rounded-square cylinder under the effect of proximity interference by a stationary splitter plate downstream, a numerical study is presented for various corner-radius R(0.1−0.5), reduced velocity U*(2−12.5), cylinder-plate gap G*(0.3,2.0), Reynolds number Re = 100, mass ratio M*=1, damping coefficient ζ=0.005, plate-length L*=1, and plate-thickness t*=0.05. For various R, a vortex-induced vibration (VIV)-type of amplitude response is observed at G*=2.0, while a galloping-like response is shown for the smaller G*=0.3. For the VIV response, the sharpness of the cylinder (decreasing R) leads to a vibration-suppression and a narrower VIV lock-in region. For the galloping response, the decreasing R leads to a marginal increase in the cylinder amplitude A* and a significant decrease in frequency f* of vibration. Destructive and partial interactions of the cylinder–plate vortices are found in the near-wake, whereas in the far-wake, vortex-shedding patterns are affected by the rounded corners of the cylinder, leading to six different types of patterns. The vortex interaction, vortex shedding, and amplitude response are found to be inter-related to each other—examined with the help of regime maps for the various modes of vortex interactions and vortex shedding. The downstream splitter plate proximity-induced transition—from the VIV-to-galloping amplitude response—leads to an enhancement in the amplitude of vibration, which is larger for a sharper rounded-square cylinder as compared to that for a circular cylinder.
Inverse transform sampling for efficient Doppler-averaged spectroscopy simulations
Authors: Rotunno Andrew P. , Robinson Amy K. , Prajapati Nikunjkumar , Berweger Samuel , Simons Matthew T. , Artusio-Glimpse Alexandra B. , Holloway Christopher L.
Published: July 2023

We present a thermal velocity sampling method for calculating Doppler-broadened atomic spectra, which more efficiently reaches convergence than regular velocity weighted sampling. The method uses equal-population sampling of the 1D thermal distribution, sampling the “inverse transform” of the cumulative distribution function, and is broadly applicable to normal distributions. We also discuss the efficiency by eliminating velocity classes, which do not significantly contribute to the observed atomic lines, and comment on the application of this method in two- and three-dimensions.
Shallow donor impurity of bismuth in silicon: Peculiar electrical properties of bismuth-related defects produced by electron irradiation
Authors: Emtsev Vadim , Abrosimov Nikolay , Kozlovski Vitalii , Oganesyan Gagik , Poloskin Dmitrii
Published: July 2023

Electrical measurements are taken on bismuth-doped silicon subjected to electron irradiation at room temperature. The analysis of experimental data obtained in a temperature interval of 30–300 K shows a considerable decrease in the concentration of the shallow donor states of Bi in irradiated samples due to the formation of electrically neutral Bi-related complexes, which, in turn, are ascribed to bismuth–vacancy pairs. They are very stable up to T ≈ 300 °C. The contribution of radiation-produced acceptors in an irradiated material appears to be of minor importance. Unexpectedly, the behavior of the mobility of charge carriers in the course of irradiation and isochronal annealing displays very strange features. It is thought that this striking effect is accounted for by a split atomic configuration of bismuth–vacancy pairs, in sharp contrast to the well-known configuration of phosphorus–vacancy and arsenic–vacancy pairs.
Tripolar vortices in inhomogeneous magnetoplasmas in the presence of non-Maxwellian electron distributions
Authors: Alhejaili Weaam , Naeem Ismat , Masood W. , Ismaeel Sherif M. E. , El-Tantawy S. A.
Published: July 2023

Nonlinear equations governing the characteristics of tripolar vortices (TPVs) are investigated in an inhomogeneous magnetoplasma having inertialess non-Maxwellian electrons that obey the Cairns, kappa, and (r, q)-distributions. Analytical and numerical solutions of the nonlinear equations are presented for various possible cases. In this regard, the dispersion relation for the drift ion-acoustic waves (IAWs) is derived, and the condition describing the shear flow instability is discussed. It is realized that enhancing the impact of non-Maxwellian electrons in the aforementioned three distributions modifies the size and formation of TPVs. It is found that the increase in the electron concentration in the regions of low-phase space density leads to enhancement in the size of TPVs and the perturbation potential as compared to the effect of increasing concentration of electrons in the regions of high phase space density. The riveting interplay of low and high-energy electrons with spiky distribution and the resulting novel effects on the propagation of vortex structures are also discussed in detail. The present study is useful to understand the (non)linear propagation characteristics of the drift IAWs in space plasmas with special reference to the F-region of the ionosphere and also in laboratory experiments where the nonthermal distribution functions are usually found.
Intralayer spatial carrier separation capability for visible light driven photocatalytic properties of SnGe2N4-layered nanostructure: A first-principles study
Authors: Barma Shrabanti , Hasan Khan Md. Sakib , Islam Md. Rafiqul , Hasan Md. Tanvir
Published: July 2023

Recently, semiconductor photocatalysts for green hydrogen (H2) fuel require two-dimensional (2D) material with semiconducting direct bandgap and enhanced visible light absorptions. In this study, the first-principles calculation of the 2D layered nanostructure of SnGe2N4 is presented for photocatalysis applications, which has a direct bandgap of 1.73 eV/2.64 eV (Perdew–Burke–Ernzerhof/Heyd–Scuseria–Ernzerhof with generalized gradient approximation) with enhanced optical absorptions. The structure is checked to confirm the chemical formidability and dynamical steadiness by formation energy calculations and phonon dispersions. To attain the tunability of electronic and optical properties, biaxial strains, together with tensile and compressive strains, are incorporated, and it is found that compressive strain widens the bandgap, whereas tensile strain causes bandgap reduction. Biaxial strains also improve the optical absorption and the highest absorption coefficient is obtained at ∼1.47 ⨯ 105 cm−1 for 6% compressive strain, comparable to conventional perovskite materials. However, in the visible spectrum, the highest absorption coefficient is obtained for 6% tensile strain. The calculated photocatalytic band edges suggest that this material has sufficient kinetic overpotential for photo redox at compressive strains in both pH = 7 and pH = 0. In addition, the spatial carrier separation is achieved due to having a large intralayer effective potential deviation of ∼6.96 eV, as well as intralayer spatial atomic group contribution in the valance band maximum and conduction band minimum. Conclusively, the analysis in this study can be a theoretical background of this layered nanostructure as a potent photocatalyst for water splitting.
Resolving the taxonomy of the Antarctic feather star species complex Promachocrinus ‘kerguelensis’ (Echinodermata: Crinoidea)
Authors: McLaughlin Emily L. , Wilson Nerida G. , Rouse Greg W.
Published: July 2023

An increasing number of Antarctic invertebrate taxa have been revealed as cryptic species complexes following DNA-based assessments. This ultimately necessitates a morphological reassessment to find traits that will help identify these cryptic or pseudocryptic species without the need for sequencing every individual. This work concerns comatulid crinoid echinoderms long considered to represent a single, circum-Antarctic species, Promachocrinus kerguelensis. The first molecular studies sought to distinguish the diversity in the complex and understand the constituent species distributions but stopped short of formal taxonomic assessment. Here, we continued to increase sample representation around the Southern Ocean and sequenced the mitochondrial COI gene for all new specimens, and additional genes for a few representatives. We also elucidated previously unappreciated features, particularly body pigmentation and morphology of the centrodorsal ossicle in an attempt to diagnose some species morphologically and based on DNA data. The species complex within Promachocrinus is here resolved into P. kerguelensis Carpenter, 1879, P. vanhoeffenianus Minckert, 1905, P. joubini Vaney, 1910, P. mawsoni (Clark, 1937) comb. nov. (transferred from Florometra) and four previously unnamed species, P. fragarius sp. nov., P. unruhi sp. nov., P. uskglassi sp. nov. and P. wattsorum sp. nov. Although most species can be distinguished morphologically, several cannot be reliably separated without DNA data. All sequenced species are essentially circum-Antarctic, with the notable exception of P. wattsorum sp. nov. that is restricted to the Prince Edward Islands in the sub-Antarctic Indian Ocean and P. vanhoeffenianus that is only known from the type locality in the Davis Sea. The vast nature of the Antarctic and Southern Ocean ecosystem dictates large scale sampling to understand the full extent of the biodiversity. ZooBank: urn:lsid:zoobank.org:pub:F871CDC8-973B-48CE-8A61-33658D4EB4B1
Teaching and assessment of the future today: higher education and AI
Authors: Lacey Melissa M. , Smith David P.
Published: July 2023

Artificial intelligence (AI), once a subject of science fiction, is now a tangible, disruptive force in teaching and learning. In an educational setting, generative large language models (LLM), such as OpenAI’s ChatGPT, perform and supplement tasks that usually require human thought, such as data analysis, understanding complex ideas, problem-solving, coding and producing written outputs. AI advances are moving quickly. From the emergence of ChatGPT 3.5 in November 2022, we have witnessed the arrival of other progressive language models, like OpenAI’s GPT-4, Google’s Bard AI and Microsoft’s Bing AI. Most recently, AIs gained the ability to access real-time information, analyse images and are becoming directly embedded in many applications.
Conditioning to predators improves survival of stocked Murray cod (Maccullochella peelii) fingerlings
Authors: Hutchison Michael , Butcher Adam , Norris Andrew
Published: July 2023

Context Following recent major fish kill events, there is increasing interest in stocking Murray cod fingerlings to help fish stocks recover. Strategies that can increase post-release survival of stocked fingerlings are important for conservation stocking of Murray cod and may also have application to other species. Aims The aim of this work was to evaluate whether pre-release predator recognition and avoidance training conferred a survival advantage on stocked Murray cod (Maccullochella peelii) fingerlings. Predator-free release enclosures were also evaluated as a method to improve survival. Methods Fingerlings were trained by exposure to predators and skin extract. Fingerlings were marked with visual implant elastomer (VIE) tags to denote training status and release strategy (trained, untrained, soft release, standard release). Fingerlings were released at three sites in the northern Murray–Darling Basin. Marked fish were recaptured by electrofishing 24 h post-release and quarterly up to 15 months post-release. Key results Trained Murray cod had higher relative survival than did untrained fish. The mean recapture rate of trained fish was twice that of untrained fish. Fingerlings released directly into the waterbody had significantly higher recapture rates than did fingerlings acclimated for 90 min in predator-free enclosures. Conclusions Predator conditioning training provides a survival advantage to stocked Murray cod fingerlings. However, predator-free release enclosures conferred a disadvantage. Implications Pre-release training of Murray cod fingerlings could be beneficial to conservation and recreational-fish stocking programs. We recommend stocking trained cod fingerlings directly into the receiving environment, rather than into soft-release enclosures, so as to maximise their chance of survival.
Didactic audiovisual translation
Authors: Bolaños García-Escribano Alejandro , Ogea Pozo María del Mar
Published: July 2023

This paper discusses the uses and applications of interlingual subtitling for the d/Deaf and hard of hearing (SDH)
in the language classroom and builds on a pilot experiment involving over a hundred students who partook in a didactic initiative
based on the use of SDH.

The present study forms part of the TRADILEX (2020–2023) international project, which draws on action-oriented
approaches to produce didactic sequences of didactic audiovisual translation (AVT) and media accessibility (MA) tasks in
foreign language education (FLE).

A pilot experiment involving didactic interlingual captioning (Spanish into English) was carried out with two
cohorts of students (N = 104) from two undergraduate programmes at a Spanish higher-education institution. The
results shed light on the students’ perception of didactic SDH, as well as the pedagogical benefits of learning English by
captioning video clips. The students boosted their translation skills in different ways, and awareness was raised on the
importance of analysing visual, acoustic and paralinguistic information when localising clips.

Ultimately, this paper examines the potential benefits of action-oriented captioning tasks and advocates for
integrating didactic AVT-MA into the FLE curriculum.
Reverse subtitles in foreign language learning
Authors: Ragni Valentina
Published: July 2023

This paper reports on an eye-tracking study investigating the processing and mnemonic retention of reverse subtitles (foreign-language subtitles presented alongside native-language audio) in learners of Italian as a Foreign language (IFL). 26 English native speakers with a CEFR B2+ Italian level watched an English clip with Italian subtitles in two translation conditions, formal similarity (literal transfer) and formal discrepancy (non-literal transfer). Immediately after watching, they answered recognition and recall questions. This study examines memory, attention allocation and the concept of noticing, which was investigated through triangulation of eye tracking, verbatim recognition and explicit reports. Data analysis methods include generalised mixed-effect modelling. Results revealed that reverse subtitles have acquisitional potential for advanced IFL learners, noticing can be probed experimentally, and formal (dis)similarity appears to have some psychological reality in the mind of the learner, being able to affect both recognition and recall. Evidence of novel word learning as well as deepening of existing knowledge emerged from the analyses, supporting the view that reversed subtitles could be more fruitfully exploited in FLL contexts. The paper presents details of the data analyses, discusses them in relation to Second Language Acquisition (SLA) and psycholinguistic concepts, and draws some recommendations based on the findings.
Saipanese English
Authors: Hess Dominique B.
Published: July 2023

In this volume, the emergence of English in Saipan is examined in the complex context of its colonial past. The focus lies on the influence of the American era on the linguistic outcomes in Saipan. Sociolinguistic interviews with indigenous Chamorros and Saipan Carolinians were analyzed using qualitative and quantitative methods. A general overview of the English spoken in Saipan and detailed analyses of selected morphosyntactic features are presented. The English spoken by the local people presents an interesting transitional phase of English becoming a first language with unique local ‘island’ features. Results shed light on linguistic constraints globally and on social constraints in Saipan that motivate language variation and change locally. This volume contributes to the literature of language variation and change, lesser-known varieties of English, and the description and categorization of emerging English varieties within the canon of World Englishes.
Periodic analogues of the Kerr solutions: a numerical study
Authors: Peraza Javier , Reiris Martín , Ortiz Omar E
Published: July 2023

In recent years black hole configurations with non standard topology or with non-standard asymptotic behavior have gained considerable attention. In this article we carry out numerical investigations aimed to find periodic coaxial configurations of co-rotating3+1vacuum black holes, for which existence and uniqueness has not yet been theoretically proven. The aimed configurations would extend Myers/Korotkin-Nicolai’s family of non-rotating (static) coaxial arrays of black holes. We find that numerical solutions with a given value for the areaAand for the angular momentumJof the horizons appear to exist only when the separation between consecutive horizons is larger than a certain critical value that depends only onAand|J|. We also establish that the solutions have the same Lewis’s cylindrical asymptotic behavior as van Stockum’s infinite rotating cylinders. Below the mentioned critical value the rotational energy appears to be too big to sustain a global equilibrium and a singularity shows up at a finite distance from the bulk. This phenomenon is a relative of van Stockum’s asymptotic collapse, manifest when the angular momentum (per unit of axial length) reaches a critical value compared to the mass (per unit of axial length), and that results from a transition in the Lewis’s class of the cylindrical exterior solution. This remarkable phenomenon seems to be unexplored in the context of coaxial arrays of black holes. Ergospheres and other global properties are also presented in detail.
Massless Dirac perturbations in a consistent model of loop quantum gravity black hole: quasinormal modes and particle emission rates
Authors: Albuquerque Saulo , Lobo Iarley P , Bezerra Valdir B
Published: July 2023

We consider perturbations of the massless Dirac field in the background of a black hole solution found by Bodendorfer, Mele, and Münch (BMM), using a polymerization technique that furnishes contributions inspired by loop quantum gravity (LQG) Theory. Using the sixth order WKB method, we analyzed its quasinormal modes for several modes, multipole numbers and the two classes of BMM black holes. We also considered the potential that governs these perturbations to analyze the bound on the greybody factor (GF) due the emission rates of particles. As results, we found that the LQG parameters are responsible for raising the potential and the real and imaginary parts of the quasinormal frequencies and decrease the bound on the GF for the two classes of black holes (with more prominent effects for the de-amplification case, which is compatible with previous analyses done for other fields).
Dependence of electron and neutral vapor density distributions on anode mode of high current vacuum arc
Authors: Hirano Yuichi , Kikuchi Ryo , Ejiri Haruki , Kumada Akiko , Hidaka Kunihiko , Inada Yuki
Published: July 2023

The vacuum arc discharge makes transition to a footpoint mode, anode spot type 1 (type 1) mode and anode spot type 2 (type 2) mode under high current conditions. The mode dependence of the electron and metal vapor densities were experimentally quantified using dichroic Shack–Hartmann type laser wavefront sensors. In the type 1 mode, the electron and metal vapor densities were about 2.5 times higher than the footpoint mode. The electron density of the type 2 mode was three times higher than that of the type 1 mode, while significant difference was not found in the metal vapor density. Such higher electron density for the type 2 mode than the type 1 mode was coherent with a previous result obtained by Stark broadening. The present electron and metal vapor density measurement demonstrated that the amount of the electrode erosion was in the following order: footpoint mode < type 1 mode < type 2 mode, which agreed with a previous study.
Reactive molecular dynamics simulations on the pyrolysis of SF6
Authors: Li Haotian , Zeng Fuping , Zhang Mingxuan , Zhu Kexin , Yao Qiang , Tang Ju
Published: July 2023

There are occasionally partial over-thermal faults in gas-insulated equipment inducing SF6 insulating medium to dissociate. It remains unclear at the atomic scale how this chemically stable gas pyrolyzes at high temperatures. To date, there is a lack of micro-level investigations on the molecular behavior of SF6 at high temperatures. In particular, it requires an effective force field to characterize the evolution of the reactions involving SF6 and low-fluorine sulfides. The paper aims to fill the gap in this field by performing reactive molecular dynamics (MD) simulations. In this work, MD simulations were carried out on a system consisting of more than 100 SF6 molecules using a new developed reactive force field The dissociation of SF6 and the subsequent reactions involving low-fluorine sulfides at high temperatures were simulated. The variation of all species in the system were recorded to investigate the effects of the temperature and pressure on the pyrolysis process. The obtained data was then used to establish the relationship between the reaction rate and temperature, thereby formulating Arrhenius law. Furthermore, the trajectories of SF6 and other species were observed at the atomic level. Snapshots of key frames during the reaction helped us to explore the interaction mechanism of free F atoms with SF6 molecules and SF5 fragments. It was found that the early dissociation of SF6 mainly comes from the thermal vibrations of the molecule itself, while the later decomposition of SF6, SF5 and others is related to high-speed collisions by F atoms. This work contributes to the understanding of the mechanism of SF6 pyrolysis and lays a foundation for more MD investigations.