bluuebunny/crossref_metadata_2025 huggingface dataset:
Formation, diffusion, and accreting pollution of DB white dwarfs
Authors: Zhu Chunhua , Liu Helei , Wang Zhaojun , Lü Guoliang
Published: August 2021

Context. Over 1500 DBZ or DZ white dwarfs (WDs) have been observed so far, and polluted atmospheres with metal elements have been found among these WDs. The surface heavy element abundances of known DBZ or DZ WDs show an evolutionary sequence. Cooling, diffusion, and accretion are important physical processes in WD evolution which can alter the element abundances of the WD surface.

Aims. Using the stellar evolutionary code, we investigated the DB WD formation and the effects of input parameters −, including the mixing length parameter (αMLT), thermohaline mixing efficiency (αth), and the metallicity (Z) −, on the structures of these DB WDs. The impacts of the convective zone mass (Mcvz), cooling timescales, diffusive timescales (τdiff), and the mass-accretion rate (Ṁa) on the element abundances of the WDs’ surfaces are discussed. By comparing the theoretical model results with observations, we try to understand the evolutionary sequence of the heavy element abundance on DBZ WD surfaces.

Methods. By using Modules for Experiments in Stellar Evolution, we created DB WDs, and simulated the element diffusion due to high gravitational fields and the metal-rich material accretion coming from the planet disrupted by the WD. Then, we calculated the element abundances of these DB WDs for a further comparison with observations.

Results. In our models, the input parameters (αMLT, αth, and Z) have a very weak effect on DB WD structures, including interior temperatures, chemical profiles, and convective zones. They hardly affect the evolution of the heavy elements on the surface of DB WDs. The mass-accretion rate and the effective temperature of DB WDs determine the abundances of heavy elements. The evolutionary sequence of the Ca element for about 1500 observed DB or DBZ WDs cannot be explained by the model with a constant mass-accretion rate, but it is very consistent with the model in which the mass-accretion rate decreases by one power law when Teff > 10 kK and it slightly increases by another power law when Teff < 10 kK.

Conclusions. The observed DB WD evolutionary sequence of heavy element abundances originates from WD cooling and the change in the mass-accretion rate.
Flood risk modeling in the watershed of Charâa stream, Province of Berkane (North-Eastern Morocco)
Authors: Afif Hafssa , Oujidi Mostafa , Amarjouf Najat , Ramdani Smahane , Azougay Abdellah
Published: August 2021

The knowledge on floods in Morocco is sporadic and scattered between historical writings and natural events following each other in time and space. In this context, the identification of areas likely to be affected by floods is essential for better management of this risk. The present study aims to model the floods at the level of the two sides of the Charâa stream (the side of Berkane and Sidi Slimane Charâ). The methodology followed in this modeling consists of determining the geomorphology of the watershed and studying its hydrology. 2D hydraulic modeling by Iber software makes it possible to follow the Spatio-temporal evolution of the characteristics of a flood. In addition, it allows us to map the hazard. Furthermore, to assess vulnerability to flooding, we referred to land use (physical vulnerability) to study the behavior of runoff water in the face of socioeconomic issues such as buildings, facilities, and the road network. The results showed that: (1) - A predominance of high-intensity flood hazard in the floodplain; (2) - Land with medium and high vulnerability successively constitutes 46.50% and 31.10% of the total studied watershed area.
Sheep meat Beni-Guil breed: A local meat labeled PGI to promote quality and preserve biodiversity in Morocco
Authors: Belhaj Kamal , Mansouri Farid , Reda Melhaoui , Taaifi Yassine , Rbah Youssef , Sindic Marianne , Boukharta Mohamed , Serghin-Caid Hana , Elamrani Ahmed
Published: August 2021

Currently, meat consumers are more conscious about the authentic meat products linked to their origin, which generates a growing demand for labeled sheep meat. In eastern Morocco, the Beni-Guil (BG) sheep meat is a Protected Geographical Indication (PGI) product. This study aimed to assess the variation of intramuscular fat quality of BG sheep in its cradles (Cr). The chemical composition of the longissimus lumborum muscle was evaluated from 20 female lambs obtained in the two main cradles of the BG breed (Ain Beni-Mathar (BG-Cr1) and Tendrara (BG-Cr2). The results show that the FA profile was affected by Cr (p<0.05). The oleic acid, palmitic acid, stearic acid, and linoleic acid are the dominants FA of analyzed meats. The polyunsaturated fatty acids (PUFA)/saturated fatty acids (SFA) and PUFA n-6/PUFAn-3 ratios respectively range from 1.15 and 5.02 for BG-sheep meats from Cr1 to 1.36 and 10.73 for those from Cr2. Overall, the results indicate that the analyzed meats have an interesting FAs profile with favorable ratios and indices. Thus, this study provides new information on the lipid quality of BG-IGP sheep meat produced extensively in two main cradles of this typical Moroccan sheep breed.
Metallic trace elements contained in the sediments of Dayet Er-Roumi Lake (Morocco)
Authors: El Ghizi Sara , Hssaissoune Sliman , El Bouch Mohammed , Sadik Mohamed , Hasnaoui Mustapha
Published: August 2021

The contamination of aquatic ecosystems with metals remains a serious environmental problem of growing concern. Sediments are often studied as reservoirs or wells for many chemical pollutants. They are micropollutant traps; they also indicate the watercourse's historical pollution, lagoons, and lakes…Lake Dayet Er-Roumi (SIBE) is the only permanent natural lake in the Khemisset region (Morocco); this wetland is affected by several forms of pollution that are mainly linked to human activities (agricultural, domestic, industrial, etc.). The objective of our study is to contribute, through qualitative and quantitative analysis, to the assessment of lake sediment pollution by Spatio-temporal monitoring of certain toxic heavy metals such as Mn, Zn, Cr, Cd. These sediments are collected on the level of the lake's surface; the concentration of heavy metals was measured by microwave plasma atomic emission spectroscope (MP-AES). Metal analyses carried out at three measuring points during the winter season reveal a high concentration of Zn, Cr, and Mn at all stations during the winter season, which far exceeds the recommended standards, with a low level of Cd. The contamination factor "FC" and the degree of contamination "DC" reveal polymetallic contaminations dominated by two elements, zinc, and Chromium, which are the most worrying. These results clearly show that lake Dayet Er-Roumi is polluted; strategies to limit the lake's pollution must be implemented to avoid several ecological problems (fish mortality, etc.).
Study on the Material Model and Hot Working Drawing of a New Type of High Temperature Titanium Alloy Ti-Al-Nb
Authors: Fang Shuang , Zhang Mincong , Yu Qiuying , Xiong Huaping
Published: August 2021

This paper proposes an exploratory study on the preparation of titanium-based superalloys through the Ti+Al+Ti2AlNb three-component hybrid hot press sintering method. Through the hot press sintering experiment of the mixed powder under different heating and sintering processes, the plastic deformation behavior of the material is carried out on this basis Research, preliminarily discuss the constitutive relationship of the new high-temperature titanium alloy Ti-Al-Nb, establish the hot working map and recrystallization model.
Photovoltaic MPPT Algorithm Based on Hybrid Boost Converter and Variable Step Size Incremental Conductance
Authors: Ma Yiwei , Wang Fuxing , Huang Zongsheng , Feng Qin , Piao Changhao
Published: August 2021

Aiming at the problem of low voltage gain of traditional boost converter and the incompatibility of tracking speed and tracking accuracy with the traditional incremental conductance algorithm (INC), this paper uses the hybrid boost converter as the DC/DC converter of photovoltaic system, and designs the variable step size INC algorithm control strategy to achieve Maximum power point tracking (MPPT) of photovoltaic. Simulink simulation model verifies the feasibility of the proposed algorithm, which effectively improves the output voltage and power generation efficiency of the photovoltaic system.
The Nonlinear Time Sequence Analysis in the Alpine-Himalayan Earthquake Zone
Authors: Chen Jiemin , Yan Zelin , Xu Linfeng , Liu Zhixin , Liu Yan , Tian Jiawei
Published: August 2021

The characteristics of the earthquake activity in the Eurasian earthquake zone, which is the second largest earthquake zone in the world, was investigated by researchers. The earthquake activity of the Eurasian earthquake zone was analysed in various disciplines, such as earth dynamics, rock mechanics, geology and tectonics. The emergence of fractal theory provided a new direction in exploring the characteristics of the earthquake activity in the Eurasian earthquake zone. This study processed the data on the earthquake activity in the Eurasian earthquake zone by self-similarity method and scaled invariant feature test and used the rescaled range analysis method to analyse the nonlinear time series fractal characteristics of the earthquake activity in the Eurasian earthquake zone. Results show that the time series of earthquake activity in the study area is not an independent Poisson process, which exhibits the characteristics of scale invariance and long-range correlation. Approximately 80% of the H values of the earthquake activity iteratively increase and decrease for moderate earthquakes, which is mainly concentrated during the increasing stage. The time difference of the H value between the two-neighbouring earthquake shows that the H value fluctuates in the active earthquake region and is stationary in the relatively stable region. Strong earthquakes will likely occur in the next few years because the H value fluctuates.
Evaluation of Uncertainty in Determination Methods of Seawater pH Standard Material
Authors: Shi Chaoying , Zhao Hong , Zhang Xiaohui , Luo Yan
Published: August 2021

Seawater pH standard material is determined by potentiometric methods with hydrogen electrode silver / silver chloride electrode in non-liquid junction cell. As a standard material, uncertainty is an important quality parameter. The sources of the uncertainty of determination methods mainly include measurement repeatability and temperature, atmospheric pressure, electrode potential, chloride concentration and so on. According to the experimental data, the expanded uncertainty of the method is 0.004. Finally, through in-depth analysis of the influence weight of each component, it is found that the quality control of the standard electrode potential, measurement repeatability and chloride ion concentration of the electrode in the ion system is the key to ensure the accuracy of the setting value, which provides a reliable guarantee for the replication of reference materials.
Application of Derivative Transform Spectroscopy in Gas Detection
Authors: Chen Tingting , Wang Chun , Liang Jingqiu , Li Jingsong
Published: August 2021

Digital filtering technique is of great significance in real-time signal processing and analysis, but the stability, efficiency and flexibility of filter algorithm are important indicators to reflect its application value. In this paper, an adaptive derivative transformation based on Savitzky-Golay filter algorithm was proposed for laser absorption spectroscopy analysis. To demonstrate this analysis algorithm, first-order and second-order derivative spectroscopy are evaluated for the analysis of infrared methane absorption spectra, and compared with the original direct absorption spectral signals. The results indicated that the proposed signal processing algorithm has good performance on noise suppression and spectral resolution improvement, and the 2nd derivative spectroscopy shows better de-noising efficiency.
Photovoltaic Power Prediction Considering the Influence of Smog on Solar Radiation
Authors: Gao Tianlong
Published: August 2021

As smog significantly weakens the intensity of solar radiation, the impact of smog on photovoltaic power generation cannot be ignored. This article aims to improve the prediction accuracy of photovoltaic power generation under smog weather. The impact of main atmospheric meteorological factors on atmospheric aerosols under smog weather is studied, and radial basis function neural network is adopted to predict the optical thickness of atmospheric aerosols; then, the inclined plane radiation model is established to predict the radiation intensity received by the photovoltaic panel; finally, considering fully the factors affecting the photovoltaic power generation under the smog weather, the RBF neural network is used to predict the photovoltaic power. Experimental verification proved that the presented photovoltaic power prediction model has high accuracy.
Dissolved Oxygen Measurement in Seawater and Sensor Calibration Method
Authors: Gao Shun , Zhang Yingying , Feng Xiandong , Yuan Da , Wu Bingwei , Zhang Yunyan
Published: August 2021

The development and key calibration methods of the sensors for the measurement and automatic monitoring of dissolved oxygen in seawater have always been the research focus in the field of Marine monitoring technology. This paper summarizes the measurement methods of dissolved oxygen in seawater, the working principle and advantages and disadvantages of different dissolved oxygen sensors, and the research on calibration methods of mainstream optical dissolved oxygen sensors. Especially for optical dissolved oxygen sensors with better stability, longer service life and stronger anti-interference ability, several laboratory calibration methods which have been developed and applied, as well as in situ calibration methods which are still in the research stage are analyzed.
Design and Optimization of Rubber Tube of Orifice BoP
Authors: Liu Zhi
Published: August 2021

The rubber tube is made of rubber material. It is the important part of the orifice boP. The rubber tube is squeezed and deformed to contact with the drill pipe to achieve the sealing function. There are large deformation and contact problems in the sealing process of rubber, which is difficult to calculate theoretically. In this paper, finite element analysis software is used to analyze the contact stress between the designed rubber cylinder and the drill pipe under different loads and the influence of friction factor on the contact stress. The influence rules are summarized, the structure of the rubber cylinder is optimized, and the contact stress of the optimized rubber cylinder is analyzed. The results meet the design requirements.
Ganganalyse mit dem
instrumentierten Laufband
Authors: Häusler Kirsten
Published: August 2021

Seit über 3 Jahren führe ich Messungen von Hunden auf dem
instrumentierten Laufband durch. Begonnen hat alles mit dem Wunsch, eine
objektive Messtechnik zu finden, die sowohl wenig Raum benötigt als auch
zuverlässig und schnell Daten zum Gangbild des Hundes liefert. Das
drucksensitive Laufband mit Kameraeinsatz macht die
Überprüfbarkeit unserer subjektiven Befunde sowie die
Verlaufskontrolle der eingesetzten Therapien routinemäßig
möglich.
4 Fachleute – 4 Strategien: Chronische Obstipation beim Hund
Authors: Iben Christine , Scharwey Reinhold , Zohmann Andreas , Tratsis Imke
Published: August 2021

Der Fall: Ihnen wird ein 10-jähriger Golden Retriever mit einer
chronisch-rezidivierenden Obstipation vorgestellt. Wie gehen Sie vor und welche
Maßnahmen eignen sich, um die Lebensqualität des Hundes zu
verbessern?
Vergleich der sechs Ausgaben des Organons unter besonderer Berücksichtigung der Arzneimittelpotenzierung
Authors: Kohsareh Duniea Safavi
Published: August 2021

In der vorliegenden Arbeit wird im Speziellen das Hauptwerk Samuel Hahnemanns, des Begründers der Homöopathie, ergründet. Seine genauen Erkenntnisse veröffentlichte er im „Organon der rationellen Heilkunde“ und in zahlreichen Publikationen. Im Laufe der Zeit kam es zu 6 Auflagen des Organons, die hier näher betrachtet und verglichen werden sollen. Im Folgenden wurden die Paragraphen unter besonderer Betrachtung der Arzneimitteldosierung und deren Verabreichungsform analysiert. Die Arzneimittelpotenzierung unterlag mehreren Änderungen sowie Erneuerungen. Vor allem in den beiden letzten Auflagen des Organons kam es zu essenziellen Dosierungsänderungen, die bis heute zu einer zum Teil unterschiedlichen Linie unter den Homöopathen geführt haben.
Der §4 des Organons in seiner zeitlosen Gültigkeit und zunehmenden Brisanz
Authors: Hadulla M.M.
Published: August 2021

Kasuistik einer jungen Frau (17 Jahre) mit schwerer Depression und suizidalen Gedanken unter der Einnahme von oralen Kontrazeptiva.
Empfehlungen aus der Praxis
Authors: Albrecht Daniela
Published: August 2021

Diese neue, kurze Rubrik soll für Einsteiger oder Wiedereinsteiger praxisrelevante Themen aufgreifen, diese auffrischen und so die Anwendung der Homöopathie in der Praxis erleichtern. Dabei gibt der jeweilige Autor seine langjährigen Erfahrungen weiter und stellt ein mögliches Vorgehen vor. Bewusst werden dabei nicht jegliche in der Literatur beschriebenen Varianten erwähnt, sondern der Schwerpunkt wird auf eine pragmatische Umsetzung gelegt, die leicht und unkompliziert angewendet werden kann. Davon abweichende Meinungen und Erfahrungen sind berechtigt, aber nicht Thema der Reihe. Am Ende gibt es einige Literaturempfehlungen mit passenden Seitenangaben zu den jeweiligen Themen.
Inferior Turbinate Reduction during Rhinoplasty: Is There Any Effect on Rhinitis Symptoms?
Authors: Garcia João Pedro T. , Moura Bianca H. de , Rodrigues Vinícius H. , Vivan Manoela A. , Azevedo Simone M. de , Dolci José Eduardo L. , Migliavacca Raphaella , Lavinsky-Wolff Michelle
Published: August 2021

Introduction Inferior turbinate surgery is often performed concomitantly with rhinoseptoplasty. As inferior turbinates play a major role in allergic rhinitis, it seems reasonable to suggest that inferior turbinate surgery reduces allergy.

Objective To assess the impact of nasal turbinate surgery on non-obstructive allergic symptoms (nasal discharge, sneezing, pruritus, and allergic conjunctivitis) and on the use of allergic medication in patients with allergic rhinitis undergoing rhinoseptoplasty.

Methods Secondary analysis of aggregated data from two randomized controlled trials. Participants with allergic rhinitis aged ≥ 16 years were recruited. Data from two groups were analyzed: patients with rhinoseptoplasty and concomitant turbinate reduction (intervention group) and patients with rhinoseptoplasty only (control group). The 90-day postoperative frequency of non-obstructive allergic symptoms and of nasal steroid and oral antihistamine use were analyzed.

Results A total of 100 patients were studied. The groups were similar in terms of allergic symptom intensity and mean age. The frequency of non-obstructive allergic symptoms decreased 90 days postoperative in both groups (p < 0.01). There was no difference between the groups in the frequency of non-obstructive allergic symptoms at 90 days (p = 0.835). Topical nasal steroid and oral histamine antagonist use decreased in the intervention group at 90 days (p < 0.05).

Conclusions Ninety days after the surgery, turbinate reduction performed in association with rhinoseptoplasty did not reduce the frequency of non-obstructive allergic symptoms more than rhinoplasty alone. However, the observed decrease in nasal steroid and oral antihistamine use suggests an impact of turbinate reduction on medication use in patients with allergic rhinitis undergoing rhinoseptoplasty.

Trial Registration ClinicalTrials.gov database (NCT01457638 and NCT02231216).
Maternal and Neonatal Outcomes in Nulliparous Participants Undergoing Labor Induction by Cervical Ripening Method
Authors: Andrikopoulou Maria , Bushman Elisa T. , Rice Madeline M. , Grobman William A. , Reddy Uma M. , Silver Robert M. , El-Sayed Yasser Y. , Rouse Dwight J. , Saade George R. , Thorp John M. , Chauhan Suneet P. , Costantine Maged M. , Chien Edward K. , Casey Brian M. , Srinivas Sindhu K. , Swamy Geeta K. , Simhan Hyagriv N. ,   for the Eunice Kennedy Shriver National Institute of Child Health Human Development (NICHD) Maternal-Fetal Medicine Units (MFMU) Network
Published: August 2021

Objective This study aimed to evaluate maternal and neonatal outcomes by method of cervical ripening for labor induction among low-risk nulliparous individuals.

Study Design This is a secondary analysis of a multicenter randomized trial of labor induction at 39 weeks versus expectant management in low-risk nulliparous participants. Participants undergoing cervical ripening for labor induction in either group were included. Participants were excluded for preripening membrane rupture, abruption, chorioamnionitis, fetal demise, or cervical dilation ≥3.5 cm. Cervical ripening was defined by the initial method used: prostaglandin only (PGE; referent), Foley with concurrent prostaglandin (Foley-PGE), Foley only (Foley), and Foley with concurrent oxytocin (Foley-oxytocin). Coprimary outcomes were adverse maternal and neonatal composites. Secondary outcomes included cesarean delivery and length of labor and delivery (L&D) stay. Multivariable analysis was used to adjust for patient characteristics.

Results Of 6,106 participants included in the trial, 2,376 (38.9%) met criteria for this analysis. Of these, 1,247 (52.4%) had cervical ripening with PGE, 290 (12.2%) had Foley-PGE, 385 (16.2%) had Foley, and 454 (19.1%) had Foley-oxytocin. The maternal composite outcome was similar among participants who received Foley-PGE (24.1%, adjusted relative risk [aRR] = 1.21, 95% confidence interval [CI]: 0.96–1.52), Foley (21.3%, aRR = 1.16, 95% CI: 0.92–1.45), or Foley-oxytocin (19.4%, aRR = 1.04, 95% CI: 0.83–1.29), compared with PGE (19.7%). The neonatal composite outcome was less frequent in participants who received the Foley-PGE (2.4%, aRR = 0.35, 95% CI: 0.16–0.75) or Foley (3.6%, aRR = 0.51, 95% CI: 0.29–0.89) but did not reach statistical significance for participants who received Foley-oxytocin (4.6%, aRR = 0.63, 95% CI: 0.40–1.01) compared with PGE only (6.8%). Participants who received Foley-PGE or Foley-oxytocin had a shorter L&D stay (adjusted mean difference = −1.97 hours, 95% CI: −3.45 to −0.49 and −5.92 hours, 95% CI: −7.07 to −4.77, respectively), compared with PGE.

Conclusion In term low-risk nulliparous participants, Foley alone or concurrent with PGE is associated with a lower risk of adverse neonatal outcomes than with PGE alone. Length of L&D stay was the shortest with concurrent Foley-oxytocin.

Key Points
Declining hegemony and the sources of Trump’s disengagement from multilateral trade governance: the interaction between domestic politics and the international political economy
Authors: Poletti Arlo , Zambernardi Lorenzo
Published: August 2021

As a result of the economic and political rise of China and Trump’s decision to undermine the liberal international order, theories of hegemony have regained center stage in both policy-oriented and scholarly debates. Yet, a careful analysis of the evolution of the US foreign policy strategy in the realm of international trade politics reveals that traditional theories of hegemonic decline are ill-equipped to account for both the timing and the content of the Trump administration’s behavior in this issue area. This paper argues in favor of integrating structural theories of hegemonic transition/stability with an analysis of the domestic sources of trade policy preferences. To do so, we draw on the International Political Economy literature highlighting how the domestic political process triggered by the dynamics of international economic competition combined with structural forces in shaping the timing and content of the Trump administration’s disengagement from the existing multilateral trade governance structures.
On the derivative nonlinear Schrödinger equation on the half line with Robin boundary condition
Authors: Van Tin Phan
Published: August 2021

We consider the Schrödinger equation with a nonlinear derivative term on [0, +∞) under the Robin boundary condition at 0. Using a virial argument, we obtain the existence of blowing up solutions, and using variational techniques, we obtain stability and instability by blow-up results for standing waves.
Transition from one-pass mode to stepwise propagation of a guided streamer along a helium plasma jet
Authors: Pinchuk M. E. , Chen Zhaoquan , Stepanova O. M.
Published: August 2021

The transition from the one-pass mode to the stepwise mode of guided streamer propagation along a helium atmospheric pressure plasma jet is presented. The propagation of the guided streamer was recorded for a special waveform of the applied voltage, which was the superposition of ≈45 kHz bipolar square pulses and ≈350 kHz damped oscillations. Stepwise propagation of the streamer occurred at a certain voltage amplitude and gas flow rate. The transition from one-pass propagation to stepwise propagation was observed for a preturbulent gas flow with an increasing voltage amplitude. The reverse transition from stepwise propagation to one-pass propagation at a lower gas flow rate in a laminar gas flow was recorded. The transition from one mode to another is associated with an increase in the air admixed content in the helium flow.
Tunable anisotropy in ReS2 flakes achieved by Ar+ ion bombardment probed by polarized Raman spectroscopy
Authors: Yu Jing , Wang Yingying , Jiang Jie , Liang Yao , Liu Yinjie , Zhong Bo , Quan Sufeng , Zhou Mengfan , Ni Zhenhua , Guo Shuai
Published: August 2021

Crystal-orientation-dependent properties in low symmetric two-dimensional material ReS2 have inspired its novel applications in photonics, electronics, and optoelectronics. In this work, Ar+ ion bombardment is used to treat ReS2 with different thicknesses, and different amounts of defect densities are introduced in ReS2 flakes. Angular dependent polarized Raman spectra is used to probe the change in anisotropy. The intensities of mode V exhibit maximum and minimum intensities with incident polarization along the b-axis and perpendicular. The intensity ratio Imin/Imax is used as a quantity to detect the change in anisotropy. It is found that with the same defect density, the change in anisotropy in 1-layer (L) ReS2 is the highest among ReS2 flakes; thus, 1L ReS2 is susceptible to ion bombardment. With an increase in the defect density in 1L ReS2, an increase in the Imin/Imax value is observed. A phenomenological model is established to understand the quantitative relationship between defect density and anisotropy, and the isotropic scattering range associated with defects is obtained. The results here provide ways of quantitatively understanding anisotropy by angular polarized Raman spectroscopy as well as ways of tuning anisotropy in two-dimensional anisotropic materials by ion bombardments.
Simultaneous inference of the compressibility and inelastic response of tantalum under extreme loading
Authors: Schill W. J. , Austin R. A. , Schimdt K. L. , Brown J. L. , Barton N. R.
Published: August 2021

We study the deformation of tantalum under extreme loading conditions. Experimental velocity data are drawn from both ramp loading experiments on Sandia’s Z-machine and gas gun compression experiments. The drive conditions enable the study of materials under pressures greater than 100 GPa. We provide a detailed forward model of the experiments including a model of the magnetic drive for the Z-machine. Utilizing these experiments, we simultaneously infer several different types of physically motivated parameters describing equation of state, plasticity, and anelasticity via the computational device of Bayesian model calibration. Characteristics of the resulting calculated posterior distributions illustrate relationships among the parameters of interest via the degree of cross correlation. The calibrated velocity traces display good agreement with the experiments up to experimental uncertainty as well as improvement over previous calibrations. Examining the Z-shots and gun-shots together and separately reveals a trade-off between accuracy and transferability across different experimental conditions. Implications for model calibration, limitations from model form, and suggestions for improvements are discussed.
Magnetism and optical properties of LiNbO3 doped with (Fe,Ni,Ga): First-principles calculations
Authors: Lin Long , Hu Chencheng , Huang Jingtao , Yan Longbin , Zhang Mingjun , Chen Ruixin , Tao Hualong , Zhang Zhanying
Published: August 2021

Based on the first principles of the generalized gradient approximation method, the magnetic and optical properties of Fe-, Ni-doped and (Fe,Ni) co-doped LiNbO3 crystals are studied. The results show that the mono-doped LiNbO3 crystals contain magnetic atoms (Fe,Ni) leading to spin polarization, and (Fe,Ni) co-doped LiNbO3 crystals tend to the ferromagnetic state with △EFM of −143 meV. The total magnetic moment of the (Fe,Ni) co-doped LiNbO3 crystal is 5.97 μB, and the local magnetic moments of Fe and Ni are 2.99 μB and 0.93 μB, respectively. It is interesting that the introduction of the Ga atom makes the ferromagnetic state (△EFM of −285.4 meV) of the (Fe,Ni) co-doped LiNbO3 system more stable than the anti-ferromagnetic state. Although Ga atoms do not contribute to the magnetic moment, the (Fe,Ni,Ga) co-doped LiNbO3 is more conducive to the spin-polarized state. In addition, with the introduction of Fe, Ni, and Ga atoms, the visible region absorption changes significantly. Non-volatile holographic storage can be achieved by (Fe,Ni) co-doped LiNbO3, thus increasing the absorption of the visible light range. In summary, this research provides theoretical guidance for the application of LiNbO3 crystals in spintronic devices.
Dipolar polarization as an energy source of tribo-electric power generator
Authors: Taguchi Dai , Manaka Takaaki , Iwamoto Mitsumasa
Published: August 2021

Dipolar polarization in solids is proposed as an energy source of a tribo-electric power generator. This power generator does not require periodic displacement of electrodes to induce electrical current, but transient current due to dipolar depolarization conveys polarization energy to external load R. Based on the dielectric physics approach, a rigorous mathematical solution of the transient current is obtained. The transient current is described using two time-constants, α−1 and β−1, which are functions of dielectric relaxation time τ, R, static capacitance of film Cs, and capacitance of film at optical frequency C∞, and it gives one current peak at time tmax=lnβαα−β. The theoretical maximum power of this generator is half of the dipolar energy stored in films P024CsA (P0: dipolar polarization, A: working area of capacitor), and it is achieved under matching condition CsR=τ (τ: dielectric relaxation time of solids). The equivalent electrical circuit of the power source is illustrated by using current source Is=P0τA and shunt conductance Gi=εsτAL (L: thickness of film). This power generator is available in electrical circuits for use by supplying dipolar polarization P0 in a cyclic manner with mechanical force, such as rubbing.
Robust radioactive sources research method using possibility particle filter
Authors: Xu Peng , Fu Chen , Tan Zhi-Yuan , Cai Xing-fu , Qin Jin
Published: August 2021

Of growing concern for the security of many nations are numerous incidents of lost or stolen radioactive sources or materials. The detection of and search for these abnormal radioactive sources plays an important role in monitoring nuclear safety and disposal of nuclear waste. In this paper, a method for autonomously searching for radioactive sources in a flat open rectangular-shaped field through mobile platforms was proposed. In this method, by using the possibility particle filter, the search for radioactive sources was realized according to a series of radiation information measured by the mobile platform carrying a Geiger–Müller counter. According to the inverse square law and the radiation counting governed by Poisson distribution, a radioactive source localization model was constructed. Then, a mobile platform controlled by an information entropy strategy constantly moved within the search area and detected radiation at specific points. The possibility filter algorithm, implemented via the sequential Monte Carlo method, is used to update posterior probability distributions of the source parameters. The performance of the proposed search algorithm, including a comparison with a standard particle filter algorithm, is studied by simulations. The simulation experiment proves that the possibility particle filter algorithm has good robustness. The successful application of the experimental dataset collected in the simulations verifies the measurement model and theoretical consideration.
One-stage simplified lattice Boltzmann method for two- and three-dimensional magnetohydrodynamic flows
Authors: De Rosis Alessandro , Liu Ruizhi , Revell Alistair
Published: August 2021

In this paper, we propose a new simplified lattice Boltzmann method (SLBM) for magnetohydrodynamic flows that outperforms the classical one in terms of accuracy, while preserving its advantages. A very recent paper [De Rosis et al., “Double-D2Q9 lattice Boltzmann models with extended equilibrium for two-dimensional magnetohydrodynamic flows,” Phys. Fluids 33, 035143 (2021)] demonstrated that the SLBM enforces the divergence-free condition of the magnetic field in an excellent manner and involves the lowest amount of virtual memory. However, the SLBM is characterized by the poorest accuracy. Here, the two-stage algorithm that is typical of the SLBM is replaced by a one-stage procedure following the approach devised for non-conductive fluids in a very recent effort [Delgado-Gutierrez et al., “A single-step and simplified graphics processing unit lattice Boltzmann method for high turbulent flows,” Int. J. Numer. Methods Fluids 93, 2339 (2021)]. The Chapman–Enskog expansion formally demonstrates the consistency of the present scheme. The resultant algorithm is very compact and easily implemented. Given all these features, we believe that the proposed approach is an excellent candidate to perform numerical simulations of two- and three-dimensional magnetohydrodynamic flows.
Precession drift reversal and rapid transport of trapped energetic particles due to an energetic particle driven instability in the Large Helical Device
Authors: Idouakass M. , Todo Y. , Wang H. , Wang J. , Seki R. , Sato M.
Published: August 2021

Energetic particle transport by a magnetohydrodynamic (MHD) instability driven by helically trapped energetic particles is studied for a high-performance Large Helical Device plasma with kinetic-MHD hybrid simulations. It is observed in the simulation that an MHD mode with poloidal/toroidal mode numbers m/n=2/1 driven by helically trapped energetic particles causes a significant redistribution of perpendicular energetic particle pressure profile. The frequency of the MHD mode decreases rapidly at the saturation of the instability and changes sign, which indicates a reversal of the mode propagation direction. It is found that the helically trapped energetic particles interacting strongly with the MHD mode change the precession drift direction at the same time as the reversal of the MHD mode propagation direction. The helically trapped energetic particles with the precession drift reversal are transported rapidly in the radially outward direction before the original precession drift direction is recovered. The precession drift reversal and the outward transport are caused by interaction with the electric field of the MHD mode. The vast majority of trapped energetic particles which interact strongly with the MHD mode experience precession drift reversal, leading to a significant redistribution of the perpendicular energetic particle pressure profile.
Magneto-optical properties of Cr3+ in β-Ga2O3
Authors: Stehr Jan E. , Jansson Mattias , Hofmann Detlev M. , Kim Jihyun , Pearton Stephen J. , Chen Weimin M. , Buyanova Irina A.
Published: August 2021

β-Ga2O3 is a wide bandgap semiconductor that is attractive for various applications, including power electronics and transparent conductive electrodes. Its properties can be strongly affected by transition metal impurities commonly present during the growth such as Cr. In this Letter, we determine the electronic structure of Cr3+ by performing a correlative study of magneto-photoluminescence (magneto-PL) and electron paramagnetic resonance. We unambiguously prove that the so-called R1 and R2 PL lines at around 1.79 eV originate from an internal transition between the first excited state (2E) and the 4A2 ground state of Cr3+. The center is concluded to have monoclinic local symmetry and exhibits a large zero-field splitting (∼147 μeV) of the ground state, which can be directly measured from the fine structure of the R1 transition. Furthermore, g-values of the first excited state are accurately determined as ga = 1.7, gb = 1.5, and gc* = 2.1. Our results advance our understanding of the electronic structure of Cr in β-Ga2O3 and provide a spectroscopic signature of this common residual impurity.
Viscoelastic fluids with no strings attached
Authors: Hill Heather M.
Published: August 2021

Dispensing a fluid is quick and clean when the nozzle is rotated. The fluid’s elastic properties are the reason why.
Squeezed hydrogen and helium don’t mix
Authors: Lopatka Alex
Published: August 2021

The results of a high-pressure experiment that re-creates the temperatures and pressures inside Jupiter and Saturn reconcile disparate space-based observations.
The structures of protoplanetary disks
Authors: Andrews Sean M.
Published: August 2021

Astronomical observations of gas, dust, and rocky material in the disks from which planets emerge help refine theoretical ideas about how they form.
Identifying East Coast Lows with climate hazards on the eastern seaboard
Authors: Pepler Acacia S. , Imielska Agata , Coutts-Smith Aaron , Gamble Felicity , Schweitzer Martin
Published: August 2021

East Coast Lows are an important weather system that can produce severe wind, wave and rainfall events along the eastern seaboard of Australia. While a number of databases of these systems have been produced, this information has historically not been readily accessible to potential users outside the research sec-tor. This paper details the development of a new product, Maps and Tables of Climate Hazards on the Eastern Seaboard (MATCHES), that bridges this gap. It combines a new database of East Coast Lows with weather impacts across the eastern seaboard. Through use of user-defined impacts thresholds and an intuitive front-end interface, this new tool provides an easy way to link East Coast Lows with their weather impacts.
Seasonal climate summary southern hemisphere (summer 2015-16): strong El Niño peaks and begins to weaken
Authors: Pepler Acacia S.
Published: August 2021

Southern hemisphere circulation patterns and associated anomalies for austral summer 2015-16 are reviewed, with an emphasis on the tropical Pacific as well as Australian rainfall and temperatures. Following the peak of El Niño in November 2015, summer 2015-16 featured continued near-record El Niño conditions in the tropical Pacific but saw the emergence of cooler subsurface waters in the equatorial Pacific. A moderate Madden Julian Oscillation (MJO) pulse and positive Southern Annular Mode (SAM) ontributed to average to above average rainfall across much of Australia, while the Maritime Continent and parts of far northern Australia saw continued below average rainfall.Sea surface temperatures during summer 2015-16 were the warmest on record for the southern hemisphere oceans, with very warm ocean temperatures in the Indian Ocean and Australian region, including the warmest summer sea surface temperatures on record around Tasmania. Air temperatures were also warmer than normal across Australia throughout the season, with a significant heatwave in southeast Australia during December.
Continuous, multidimensional coding of 3D complex tactile stimuli by primary sensory neurons of the vibrissal system
Authors: Bush Nicholas E. , Solla Sara A. , Hartmann Mitra J. Z.
Published: August 2021

Significance

An animal’s primary sensory neurons (PSNs) translate information about the environment into neural signals that allow perception and action. While much is known about visual and auditory PSN responses to complex stimuli, somatosensory neurons have been characterized with simplified and repeatable stimuli. Thus, knowledge of somatosensory PSN representational capacity remains incomplete. We used the rodent whisker system to examine how tactile mechanical information is represented in PSNs of the trigeminal ganglion (Vg) when the whiskers receive complex three-dimensional stimulation. In contrast to proposed codes in which subpopulations of Vg neurons encode select stimulus features, our results show that individual Vg neurons represent multiple stimulus features in a tiled and continuous manner, thus encoding large regions of a complex sensory space.
Interpreting machine learning models to investigate circadian regulation and facilitate exploration of clock function
Authors: Gardiner Laura-Jayne , Rusholme-Pilcher Rachel , Colmer Josh , Rees Hannah , Crescente Juan Manuel , Carrieri Anna Paola , Duncan Susan , Pyzer-Knapp Edward O. , Krishna Ritesh , Hall Anthony
Published: August 2021

Significance

The circadian clock is an internal molecular 24-h timer that is critical to life on Earth. We describe a series of artificial intelligence (AI)– and machine learning (ML)–based approaches that enable more cost-effective analysis and insight into circadian regulation and function. Throughout the manuscript, we illuminate what is inside the ML “black box” via explanation or interpretation of predictive ML models. Using this interpretation of our models, we derive biological insights into why a prediction was made, alongside accurate predictions. Most innovatively, we use only DNA sequence features for accurate circadian gene expression prediction. Using explainable AI, we define possible, responsible regulatory elements as we make these predictions; this critically requires no prior knowledge of regulatory elements.
A theory of direction selectivity for macaque primary visual cortex
Authors: Chariker Logan , Shapley Robert , Hawken Michael , Young Lai-Sang
Published: August 2021

Significance

Motion perception is important for primates, and direction selectivity (DS), the ability to perceive the direction a target is moving, is an essential part of motion perception. Yet no satisfactory mechanistic explanation has been proposed for the origin of DS in the primate visual cortex up until now. In this paper, we hypothesize that DS is initiated in feed-forward LGN input as a result of the dynamic differences between the ON and OFF pathways. The mechanisms we propose are biology based, and our theory explains experimental data for all spatial and temporal frequencies in visual stimuli. Exploiting temporal biases in parallel pathways is relevant beyond visual neuroscience; similar ideas likely apply to other types of neural signal processing.
Rapid interrogation of cancer cell of origin through CRISPR editing
Authors: Feng Weiran , Cao Zhen , Lim Pei Xin , Zhao Huiyong , Luo Hanzhi , Mao Ninghui , Lee Young Sun , Rivera Aura Agudelo , Choi Danielle , Wu Chao , Han Teng , Romero Rodrigo , de Stanchina Elisa , Carver Brett S. , Wang Qiao , Jasin Maria , Sawyers Charles L.
Published: August 2021

Significance

Modeling cancer formation requires introduction of relevant oncogenic perturbations into normal cells in a tissue/cell-type–specific manner. Genetically engineered mouse models are powerful but require significant time and cost to generate and maintain. The ability to edit primary epithelial cells ex vivo followed by orthotopic transplantation provides an alternative strategy for cancer modeling but requires efficient gene editing, typically in a multiplex fashion. Here we successfully engineer multigenic perturbations or chromosomal rearrangements in primary prostate organoids through single-step Cas9–sgRNA ribonucleoprotein electroporation. This approach can also address cell-of-origin questions by directly editing and transplanting freshly isolated subpopulations without the intermediate step of organoid culture, providing a rapid complement to traditional lineage tracing approaches.
Cunninghamella echinulata
. [Descriptions of Fungi and Bacteria].
Authors: UK, CAB International  , Sarbhoy A. K.
Published: August 2021

A description is provided for
Cunninghamella echinulata
. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On decaying flowers of
Cucurbita pepo
, dung and soil. DISEASE: Reported pathogenic to Spanish pumpkin (
Cucurbita maxima
) at Chandigarh and neighbouring villages in the Punjab, India by Grover (1965). Symptoms recognizable when the flowers begin to die off gradually. Diseased flowers do not open properly. Infected flowers are covered with the cottony mycelium of the pathogen and infected fruits may become detached from the plant and continue to rot on the soil. Leaves and stalks are also frequently infected. GEOGRAPHICAL DISTRIBUTION: World-wide (mostly tropical countries). TRANSMISSION: Air borne; may survive in fragments of mummified pumpkin fruit up to 32 months.
Phytophthora cactorum
. [Descriptions of Fungi and Bacteria].
Authors: UK, CAB International  , Waterhouse G. M. , Waterston J. M.
Published: August 2021

A description is provided for
Phytophthora cactorum
. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On a very wide range of host plants embracing 54 families (particularly
Rosaceae
) and over 150 genera (Nienhaus, 1960; Rangaswami, 1962) including ash, beech, cherry, conifers, apple, pear, apricot, strawberry, cucurbits, eggplant, cacti, gooseberry, rhododendron, lilac, ginseng, rhubarb, avocado, birch, maple and oak. DISEASES: Damping-off of seedlings including ash, beech, cherry and conifers; fruit rot of apple, pear, apricot, strawberry (leather rot), cucurbits and eggplant; leaf and stem rot of cacti, gooseberry, rhododendron, lilac, ginseng and rhubarb; collar rot and crown rot of apple and other fruit trees stem canker of avocado, birch, maple and oak; root rots in general. GEOGRAPHICAL DISTRIBUTION: Widespread in tempetate areas (CMI Map 280). TRANSMISSION: Soil-borne. Widely distributed in soils of apple orchards affected with collar rot (35: 685; 37: 132). Strawberry fruit in unmulched beds and wind-fall apples and pears on the ground frequently become infected by contact with infested soil (4: 101; 35: 685) where the pathogen may occur to a depth of 50 cm and persist for as long as 15 yr. in ploughland previously under apple orchards (42: 75). This has been partially explained by the irregular germination of oospores which require a dormant period (Blackwell, 1943; Legge, 1952). Apple fruit and gooseberry shoot infection are most frequent on lower branches subject to rain-splash which carry zoospores (41: 49). Long periods of rain, heavy dews, fog and high soil moisture favour the spread of the pathogen (39: 250; 45, 2553; 22: 30-31; 42: 391).
Pythium deliense
. [Descriptions of Fungi and Bacteria].
Authors: UK, CAB International  , Waterhouse G. M. , Waterston I. M.
Published: August 2021

A description is provided for
Pythium deliense
. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On
Hibiscus esculentus, Lycopersicon esculentum, Nicotiana tabacum
and
Saccharum officinarum
. Also on
Capsicum annuum, Carica papaya, Cucumis sativus, Cucurbita pepo, Datura fastuosa, Petunia
sp. and
Solanum melongena
on inoculation (Rangaswami, 1959; Herb. IMI). DISEASE: Causing damping-off of tomato seedlings, stem-burn of tobacco and fruit rot of okra. GEOGRAPHICAL DISTRIBUTION: Asia (Indonesia, Sumatra) and Australasia & Oceania (Australia, New Guinea, Papua); North America (? United States); Central America & West Indies (? N˜caragua). TRANSMISSION: Soil-borne.