bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and optimization of a magnet for magnetocaloric refrigeration
Authors: Beltrán-López Jesús Francisco , Palacios Elías , Velázquez David , Burriel Ramón
Published: October 2019

The magnetic field source is the most expensive element of a magnetic refrigeration device. The design of an efficient magnet with high and low field regions, using reduced volumes of permanent magnets, is of paramount importance for the practical application of this new technology. A two-pole rotary magnet formed by sectors of oriented hard magnets and soft iron pieces is optimized in angular width and magnetization direction of each sector. A quadratic approximation is used for the optimization of the defining angles. This procedure provides the parameters that result in extreme values of a given functional F, defined as an efficiency variable of the working device. The procedure also gives the correlation between parameters and the relative importance of the deviations with respect to their mathematical optimal values. An optimized magnet has also been built, and the resulting calculated fields are compared with experimental measurements in the real system.
A low-noise resonant input transimpedance amplified photodetector
Authors: Bowden W. , Vianello A. , Hobson R.
Published: October 2019

We present the design and characterization of a low-noise, resonant input transimpedance amplified photodetector. The device operates at a resonance frequency of 90 MHz and exhibits an input referred current noise of 1.2 pA/Hz—marginally above the theoretical limit of 1.0 pA/Hz set by the room temperature Johnson noise of the detector’s 16 kΩ transimpedance. As a result, the photodetector allows for shot-noise limited operation for input powers exceeding 14 µW at 461 nm corresponding to a noise equivalent power of 3.5 pW/Hz. The key design feature which enables this performance is a low-noise, common-source junction gate field-effect transistor amplifier at the input which helps to reduce the input referred noise contribution of the following amplification stages.
Defect-moderated oxidative etching of MoS2
Authors: Maguire Pierce , Jadwiszczak Jakub , O’Brien Maria , Keane Darragh , Duesberg Georg S. , McEvoy Niall , Zhang Hongzhou
Published: October 2019

We report a simple technique for the selective etching of bilayer and monolayer MoS2. In this work, chosen regions of MoS2 were activated for oxygen adsorption and reaction by the application of low doses of He+ at 30 keV in a gas ion microscope. Raman spectroscopy, optical microscopy, and scanning electron microscopy were used to characterize both the etched features and the remaining material. It has been found that by using a pretreatment to introduce defects, MoS2 can be etched very efficiently and with high region specificity by heating in air.
Dynamics of the soliton waves, breather waves, and rogue waves to the cylindrical Kadomtsev-Petviashvili equation in pair-ion–electron plasma
Authors: Peng Wei-Qi , Tian Shou-Fu , Zhang Tian-Tian
Published: October 2019

A lot of work has been reported to present some numerical results on pair-ion–electron plasmas. However, very few works have reported the corresponding mathematical analytical results in these aspects. In this work, we study a cylindrical Kadomtsev-Petviashvili (CKP) equation, which can be derived from pair-ion–electron plasmas. We further report some interesting mathematical analytical results, including some dynamics of soliton waves, breather waves, and rogue waves in pair-ion–electron plasma via the CKP equation. Using a novel gauge transformation, the Grammian N-soliton solutions of the CKP equation are found analytically. Based on the bilinear transformation method, the breather wave solutions are obtained explicitly under some parameter constraints. Furthermore, we construct the rogue waves using the long wave limit method. In addition, some remarkable characteristics of these soliton solutions are analyzed graphically. According to analytic solutions, the influences of each parameter on the dynamics of the soliton waves, breather waves, and rogue waves are discussed, and the method of how to control such nonlinear phenomena is suggested.
RF voltage-controlled magnetization switching in a nano-disk
Authors: Schneider Joseph D. , Wang Qianchang , Li Yiheng , Chavez Andres C. , Hu Jin-Zhao , Carman Greg
Published: October 2019

Nanomagnetic oscillators are key components for radio-frequency (RF) signal generation in nanoscale devices. However, these oscillators are primarily electric current-based, which is energy inefficient at the nanoscale due to ohmic losses. In this study, we present an actuation mechanism for magnetization switching using a multiferroic structure that relies on an RF voltage input instead of electrical current. An AC voltage with a DC bias is applied to the piezoelectric substrate and the magnetic nanodisk with perpendicular magnetic anisotropy that is attached onto the substrate, which can achieve steady magnetic oscillation when the driven voltage is at ferromagnetic resonance (FMR) of the nanodisk. Changing the DC bias changes the magnetic anisotropy of the magnetoelastic nanodisk, hence changes the FMR and oscillation frequency. The frequency modulation is quantified using the Kittel equation. Parametric studies are conducted to investigate the influence of voltage amplitude, frequency, waveform, and the thickness of the magnetoelastic nanodisk. This multiferroic approach opens possibilities for designing energy efficient nanomagnetic oscillators that have both large amplitude and broad frequency range.
Enhancement of positive pulsed corona by dielectric enclosure
Authors: Wang Xingxing , Khomenko Andrei , Shashurin Alexey
Published: October 2019

In this work, the effect of positive pulsed corona enhancement by introducing Teflon dielectric enclosure in vicinity to the electrode assembly was studied. The discharge operating in air without the dielectric was able to operate within a very narrow voltage range of approximately 200 V. The pulsing frequency was below 1.2 kHz and current peaks were below 14 mA. Increasing the applied voltage onto the positive electrode beyond this range would result in sparks between the electrodes. When the Teflon tube enclosure surrounding the high voltage electrode was used, the window of stable pulsed corona operation expanded up to 3-5 kV. The pulsing frequency increased up to 12 kHz and the current peak level increased to approximately 35 mA. Increasing voltage beyond the point with peak pulsing frequency would result in a drop of pulsing frequency until the discharge pulsations stopped completely. The Teflon enclosure was able to enhance the average power deposited into the discharge from 10 to 220 mWatt. In addition, the product gases of the enhanced pulsed corona were tested to be mostly ozone with traceable amount of NO2. The discharge used about 150 eV and 1950 eV per one ozone molecule and nitrogen dioxide molecule respectively. The reported here plasma source is promising from the power density/compactness standpoint since significant enhancement (>20 times) of the energy deposition to the discharge can be achieved compared to that of conventional positive pulsed corona.
Impact of emulsion drops on a solid surface: The effect of viscosity
Authors: Kumar Amrit , Mandal Deepak Kumar
Published: October 2019

This paper presents a study of the impact of various water in Jatropha biodiesel emulsion drops on a stainless steel surface. The composition of the emulsion is varied by changing the volume percentage of water. The effect of the change in the composition and the Weber number (We) is reported. With the increase in the percentage of water, the domination of the viscous force is observed to increase. The emulsions having lower percentages of water (less than 20%) are found to be inertia dominated, while the others (equal or greater than 20%) are viscous dominated. The maximum spreading diameter normalized by the preimpact diameter, βmax, decreases with an increase in the percentage of water due to the increased viscous losses. Consequently, the minimum splat thickness factor and the equilibrium splat thickness factors increase with the percentage of water. Higher viscous losses affect the shape of the drop during spreading as well. Emulsification delays the splashing due to the higher viscous losses. No splashing is observed for the emulsions containing 20 or higher percentage of water, since viscosity dominantly affects the impact. To confirm the effect of the viscosity, βmax obtained from the experiments are compared with that obtained from various existing models. Another purpose of the comparison is to check the suitability of the models for the emulsion drop impact. Only one model among all studied is found to compare well because the model assumes that the characteristic length for viscous dissipation is of the order of splat thickness.
Ultrathin and durable open metamaterials for simultaneous ventilation and sound reduction
Authors: Wang Xiaole , Luo Xudong , Yang Bin , Huang Zhenyu
Published: October 2019

We report an ultrathin and durable open metamaterial capable of both fluid passage and noise insulation at low frequencies. The proposed open metamaterial, denoted as the perforated and constrained acoustic metamaterial (PCAM), contains a large orifice in each unit cell. An impedance-based model was established to investigate the working mechanism and acoustic performances of the PCAM and was then verified by measurements in a sound impedance tube. With only a thickness of 1.5 mm (0.19% of wavelength), a PCAM sample exhibits a sound transmission loss of 20 dB at 430 Hz. This high-efficiency soundproof feature under the ventilation condition is attributed to the interferences of the two wave fields between the orifice area and the plate area in the near-field. The PCAM may have potential applications in limited spaces requiring high-efficiency ventilation and long-time service.
Recombination of Shockley partial dislocations by electron beam irradiation in wurtzite GaN
Authors: Belabbas I. , Vasileiadis I. G. , Moneta J. , Smalc-Koziorowska J. , Dimitrakopulos G. P.
Published: October 2019

Dissociated a-type screw dislocations in gallium nitride, comprising pairs of 30° Shockley partial dislocations separated by I2 basal stacking faults, were observed by aberration-corrected high resolution transmission electron microscopy (HRTEM). HRTEM image simulations, in conjunction with density functional theory calculations, led to the identification of the core structures of the Shockley partials. Both partials were found to belong to the glide set rather than the shuffle one, while the core with gallium polarity is reconstructed, but the one with nitrogen polarity is not. During in situ irradiation by the electron beam, the I2 stacking fault ribbon was found to shrink, ultimately leading to a remerging of the two partials. This reversal of the dissociation reaction was attributed to recombination enhanced dislocation glide, whereby the Shockley partial with nitrogen polarity was identified to be the mobile one. A possible model explaining this mobility is proposed comprising a local modification of the dislocation's electronic structure due to the presence of nitrogen vacancies at its core.
Electro-thermal synergetic effect in 0.94Bi0.5Na0.5TiO3-0.06BaZr0.2Ti0.8O3: ZnO pyroelectric composites for high-performance thermal energy harvesting
Authors: Shen Meng , Zheng An , Lin Yuli , Li Ming-Yu , Qiu Shiyong , Zhang Qingfeng , Zhang Guangzu , Jiang Shenglin
Published: October 2019

Pyroelectric energy harvesters based on lead-free ceramics cannot meet the requirement for practical applications due to their low energy conversion capacity. In this work, high-performance thermal energy harvesting with the greatly enhanced pyroelectric coefficient and rate of temperature change has been achieved by compositing the zinc oxide (ZnO) semiconductor into 0.94Bi0.5Na0.5TiO3-0.06BaZr0.2Ti0.8O3 (BNT-BZT) ceramic matrixes. The ZnO semiconductor not only provides charge carriers for accelerating the transportation of free charge to improve the pyroelectric coefficient of BNT-BZT: ZnO but also enhances the temperature variation rate dT/dt of the samples because of its high thermal conductivity. Owing to the electrothermal synergetic effect of the ZnO semiconductor, a highly improved energy harvesting performance of the energy density reaching up to 130 μJ cm−3 is achieved, which is over three times compared to that of the pristine BNT-BZT ceramics. This work will provide an effective and facile approach to develop high-performance pyroelectric composite ceramics for thermal energy harvesting applications.
Three-dimensional visualization of destruction events of turbulent momentum transfer in a plane jet
Authors: Takahashi Mamoru , Iwano Koji , Sakai Yasuhiko , Ito Yasumasa
Published: October 2019

Destruction events of momentum transfer as represented by the Reynolds (shear) stress via the pressure–rate-of-strain interaction in a plane jet are investigated using direct numerical simulation data. To obtain three-dimensional pictures of the turbulent structures, pseudo-three-dimensional data are constructed on the basis of Taylor’s frozen hypothesis from time series of the relevant quantities. The coherent motion in the plane jet is extracted by means of conditional sampling analogous to variable-interval time averaging. We obtain a large-scale coherent structure consisting of horseshoelike vortices and a Kármán-vortex-like very large spanwise vortex street. Furthermore, we find that the active Reynolds stress destruction is localized around the large-scale coherent vortex structure. However, the coherent structure itself does not contribute to the Reynolds stress destruction, but the remaining incoherent motions do. For the significant pressure–rate-of-strain events in the incoherent motion, we display invariant maps of the velocity gradient tensor and the principal axes of strain to facilitate a discussion of the consistency of the numerical results with an illustration by Hinze [Turbulence, 2nd ed. (McGraw-Hill, 1975), pp. 325–328] and with our own experimental results [Takahashi et al., “Experimental investigation on destruction of Reynolds stress in a plane jet,” Exp. Fluids 60, 46 (2019)]. Consequently, the present results suggest that the illustration of the Reynolds stress destruction by Hinze is not completely applicable to a plane jet.
Hard X-ray nanoprobe and time-resolved XEOL to observe increasing luminescence of ZnO and GaN epitaxial structures
Authors: Lin Bi-Hsuan , Wu Yu-Hao , Wu Tai-Sing , Wu Yung-Chi , Li Xiao-Yun , Liu Wei-Rein , Tang Mau-Tsu , Hsieh Wen-Feng
Published: October 2019

Hard X-ray excited optical luminescence (XEOL) with a nanofocused beam provides both excellent spatial resolution and high enough peak power density, which makes XEOL mapping and luminescence dynamics study achievable. We present here the time and X-ray intensity dependence of the near-band-edge (NBE) luminescence from the nonpolar a-plane MgZnO/ZnO multiple quantum wells (MQWs): the emission intensity increases more than 10 times after high X-ray irradiation. Different from the well-known NBE emission lifetime of ZnO (less than 1 ns), the long decay time gradually decreases from 130 ns to 35 ns with the increasing X-ray irradiation time. We attribute the observed changes in NBE luminescence to the excitation of the Mg-related energy state by the high energy X-ray nanobeam. This suggestion was further confirmed in the XEOL spectra of the Mg-doped and Si-doped c-plane GaN epi-films.
A 3-dimensional calculation of the field emission current and emission angle of a vacuum transistor as a function of gate voltage and radius of curvature of the emitter
Authors: Tsagarakis M. S. , Xanthakis J. P.
Published: October 2019

We have calculated the electrical characteristics of a vacuum transistor withsharp, pointed emitter and collector with a radius of curvature R<20nm with the aim of revealing the advantages of such emitters. For such surfaces the traditional Fowler-Nordheim theory which pertains to a parallel plate configuration is not valid. We have used a 3-dimensional WKB theory capable of calculating the distribution of the current in space. We have shown that for values of emitter radius in the range of a few nanometers the current density is enclosed within a cone of angle of approximately 6°–16° thus minimizing current losses. The Id–Vd characteristics were calculated and found to exhibit a exponential behavior and a saturation region spanning currents from 10−14A to 10−6A by only 2 Voltsvolts change in gate voltage Vg, i.e. exhibiting an extraordinary transconductance.
Thermionic enhanced heat transfer in electronic devices based on 3D Dirac materials
Authors: Huang Sunchao , Lewis R. A. , Zhang Chao
Published: October 2019

We calculate the heat transfer from electronic devices based on three-dimensional Dirac materials without and with thermionic cooling. Without thermionic cooling, the internal temperature of the devices is at best equal to and usually higher than the temperature of the surrounding environment. However, when thermionic cooling is employed to transport heat, the internal temperature can be considerably lower than the environmental temperature. In the proposed thermionic cooling process, the energy efficiency can be as high as 75% of the Carnot efficiency.
High transparency Bi2Se3 topological insulator nanoribbon Josephson junctions with low resistive noise properties
Authors: Kunakova Gunta , Bauch Thilo , Trabaldo Edoardo , Andzane Jana , Erts Donats , Lombardi Floriana
Published: October 2019

Bi2Se3 nanoribbons, grown by catalyst-free Physical Vapor Deposition, have been used to fabricate high quality Josephson junctions with Al superconducting electrodes. The conductance spectra (dI/dV) of the junctions show clear dip-peak structures characteristic of multiple Andreev reflections. The temperature dependence of the dip-peak features reveals a highly transparent Al/Bi2Se3 topological insulator nanoribbon interface and Josephson junction barrier. This is supported by the high values of the Bi2Se3 induced gap and of IcRn (where Ic is the critical current and Rn is the normal resistance of the junction) product both of the order of 160 μeV, a value close to the Al gap. The devices present an extremely low relative resistance noise below 1 × 10−12 μm2/Hz comparable to the best Al tunnel junctions, which indicates a high stability in the transmission coefficients of transport channels. The ideal Al/Bi2Se3 interface properties, perfect transparency for Cooper pair transport in conjunction with low resistive noise, make these junctions a suitable platform for further studies of the induced topological superconductivity and Majorana bound states physics.
Ferromagnetic resonance of perpendicularly magnetized Tm3Fe5O12/Pt heterostructures
Authors: Crossley S. , Quindeau A. , Swartz A. G. , Rosenberg E. R. , Beran L. , Avci C. O. , Hikita Y. , Ross C. A. , Hwang H. Y.
Published: October 2019

Broadband ferromagnetic resonance is used to investigate magnetization dynamics, damping, interfacial spin transport, and perpendicular magnetic anisotropy (PMA) of (111)-oriented epitaxial thin films of the ferrimagnetic insulator Tm3Fe5O12 (TmIG) on substrates of (111)-oriented Gd3Ga5O12. A PMA field of ∼162 mT is found at 350 K, in the temperature range where spin–orbit torque switching was previously reported [Avci et al., Nat. Mater. 16, 309–314 (2017)]. A Landé g-factor of 1.56 strongly supports large intrinsic spin–orbit coupling due to the presence of the heavy rare earth Tm. Gilbert damping coefficients α are compared for three samples: a 28 nm thin TmIG film (α ∼ 0.014), a TmIG (28 nm)/Pt (6 nm) bilayer (α ∼ 0.022), and a TmIG (28 nm)/Cu (3 nm)/Pt (6 nm) trilayer (α ∼ 0.024). Applying the spin pumping formalism, we find that the real part of the effective interfacial spin mixing conductance Geff↑↓ = 5.7 × 1014 Ω−1 m−2 is comparable to that of well-studied garnet/Pt interfaces. Our work strengthens the candidacy of TmIG for spintronics applications requiring PMA in insulating thin films.
Ultrafast carrier dynamics in colloidal WS2 nanosheets obtained through a hot injection synthesis
Authors: Zhou Pengshang , Tanghe Ivo , Schiettecatte Pieter , van Thourhout Dries , Hens Zeger , Geiregat Pieter
Published: October 2019

In recent years, hot injection synthesis has emerged as a promising route for the production of nanostructured transition metal dichalcogenides, in large due to its better control over the crystallinity and monodispersity compared to other solution based methods. Understanding the photophysics of excitons in the thus obtained colloidal nanosheets is of great importance to explore their potential for applications in optoelectronics. Here, we study the carrier dynamics in these few-layer colloidal WS2 nanosheets by use of broadband transient absorption spectroscopy. The dynamics of both the bleach, linewidth broadening and energy shift across the entire visible and near-infrared spectrum, allows us to identify subpicosecond electron trapping as the main carrier loss channel. A more quantitative analysis shows that the intrinsic properties of colloidally synthesized nanosheets are on par with other synthesis methods, paving the way for this method to produce high quality nanosheets.
Upconversion photoluminescence by charge transfer in a van der Waals trilayer
Authors: Hao Shengcai , He Dawei , Miao Qing , Han Xiuxiu , Liu Shuangyan , Wang Yongsheng , Zhao Hui
Published: October 2019

As an elementary process of light-matter interaction in solids, upconversion photoluminescence has been extensively studied in rare-earth-doped materials and found applications in biological imaging, infrared light detection, and laser cooling. More recently, it has been shown that upconversion photoluminescence can be achieved in two-dimensional semiconductors by utilizing the strong coupling between charge carriers. Here, we show that the interlayer charge transfer, which has been widely observed in van der Waals heterostructures, can be utilized for upconversion photoluminescence. Using a MoSe2/WS2/MoS2 trilayer as an example, we show that by exciting the MoSe2 and MoS2 layers with a low-energy 670-nm laser beam, photoluminescence of 620 nm can be obtained. The upconversion photoluminescence originates from the transfer of electrons and holes from MoSe2 and MoS2, respectively, to the middle WS2 layer, where they recombine. The results illustrate an unexplored physical mechanism for upconversion photoluminescence in solids and introduce van der Waals heterostructures as materials to achieve upconversion photoluminescence.
Boyden chamber-based compartmentalized tumor spheroid culture system to implement localized anticancer drug treatment
Authors: Kaneda Shohei , Kawada Jiro , Shinohara Marie , Kumemura Momoko , Ueno Ryohei , Kawamoto Tomoaki , Suzuki Kenji , Kim Beomjoon , Ikeuchi Yoshiho , Sakai Yasuyuki , Collard Dominique , Fujita Hiroyuki , Fujii Teruo
Published: October 2019

In anticancer drug development, it is important to simultaneously evaluate both the effect of drugs on cell proliferation and their ability to penetrate tissues. To realize such an evaluation process, here, we present a compartmentalized tumor spheroid culture system utilizing a thin membrane with a through-hole to conduct localized anticancer treatment of tumor spheroids and monitor spheroid dimensions as an indicator of cell proliferation. The system is based on a commercialized Boyden chamber plate; a through-hole was bored through a porous membrane of the chamber, and the pre-existing 0.4 μm membrane pores were filled with parylene C. A HepG2 spheroid was immobilized onto the through-hole, separating the upper and lower compartments. Fluorescein (to verify the isolation between the compartments) and tirapazamine (TPZ; to treat only the lower part of the spheroid) were added to the upper and lower compartments, respectively. Since the transportation of fluorescein was blocked during treatment, i.e., the upper and lower compartments were isolated, it was confirmed that localized TPZ treatment was successfully conducted using the developed system. The effect of localized TPZ treatment on cell proliferation was estimated by measuring the maximum horizontal cross-sectional areas in the upper and lower parts of the spheroid by microscopic observations. This system can, thus, be used to perform localized anticancer drug treatment of tumor spheroids and evaluate the effect of drugs on cell proliferation.
Vibrational adaptive sampling configuration interaction
Authors: Lesko Ethan , Ardiansyah Muhammad , Brorsen Kurt R.
Published: October 2019

Selected configuration interaction plus perturbation theory approaches have long been used to solve both the electronic and vibrational Schrödinger equations. In the last few years, many new selection algorithms have been developed for these approaches and applied to solve the electronic Schrödinger equation, but these algorithms have seen little to no use for solving the vibrational Schrödinger equation. Herein, we adapt one of the recently developed approaches, the adaptive sampling configuration interaction (ASCI) method, to calculate the vibrational excitations of molecules. The vibrational ASCI method has accuracy comparable to other high-accuracy approaches for solving the vibrational Schrödinger equation while requiring only modest computer resources. We study two different approaches for calculating excited states with vibrational ASCI and benchmark the method on acetonitrile and ethylene oxide. Finally, we demonstrate the applicability of the vibrational ASCI method to large systems by calculating the 128 lowest energy vibrational states of naphthalene, which has 48 vibrational degrees of freedom.
Stretching response of Rortex and other vortex-identification schemes
Authors: Kolář V. , Šístek J.
Published: October 2019

By considering a uniaxial stretching coupled with an inevitable uniform radial contraction for incompressible flow, a straightforward comparison of the stretching response for several popular vortex-identification criteria and the recently proposed vortex vector (Rortex) is presented. In addition, the outcome of the triple-decomposition method in terms of the residual vorticity tensor is employed due to its planar coincidence with Rortex. The stretching sensitivity of the examined schemes significantly differs and, consequently, reopens the persisting vortex-identification problem that the requirement of orbital compactness of the motion inside a vortex contradicts with the allowance for an arbitrary axial strain.
Locally optimized control pulses with nonlinear interactions
Authors: Ohtsuki Yukiyoshi , Namba Tomotaro
Published: October 2019

The local control theory has been extended to deal with nonlinear interactions, such as polarizability interaction, as well as a combination of dipole and polarizability interactions. We explain herein how to implement the developed pulse-design algorithm in a standard computer code that numerically integrates the Liouville equation and/or the Schrödinger equation without incurring additional high computational cost. Through a case study of the rotational dynamics control of crystalline orbital molecules, the effectiveness of the locally optimized control pulses is demonstrated by adopting four types of control objectives, namely, two types of state-selective excitation, alignment, and orientation control.
Evaluation of the 137Ba mass-marking technique and potential effects in the early life history stages of Sepioteuthis lessoniana
Authors: Chiang Chun-I , Chung Ming-Tsung , Shih Tung-Wei , Chan Tin-Yam , Yamaguchi Atsuko , Wang Chia-Hui
Published: October 2019

The use of mass-marking techniques of enriched stable isotopes has increased in studies of ecology, movement patterns and the dispersal of marine organisms. However, the efficacy of this technique and its potential effects on hatchling size and statolith chemistry of cephalopods are yet to be investigated. Sepioteuthis lessoniana egg capsules were collected from northern Taiwan and assigned randomly to 137Ba-spiking experimental groups at 0.2, 0.5 and 1ppm and three immersion durations (1, 3 and 7 days). Immersion duration >3 days produced significantly lower 138Ba:137Ba ratios, with 100% marking success, indicating that it is a reliable marking technique. The 137Ba mass marking had a positive effect on size at hatch and was likely to affect statolith trace element incorporation, including Cu, Zn and Pb. These findings highlight that it is necessary to consider the species-specific effects on hatchling size and physiological responses in when using stable isotopes mass-marking techniques.
Impact of continuous organic manuring on mechanisms and processes of the stabilisation of soil organic C under rice–wheat cropping system
Authors: Purakayastha T. J. , Das Ruma , Kumari Savita , Shivay Y. S. , Biswas Sunanda , Kumar Dhiraj , Chakrabarti Bidisha
Published: October 2019

Understanding the mechanism of soil organic carbon (SOC) stabilisation may help in developing management strategies for SOC storage. A long-term organically managed rice−wheat cropping system was used for SOC stabilisation study. Soil samples were collected from control, FYM (farmyard manure to rice and wheat), GM (green manure; Sesbania aculeata to rice and Leucaena leucocephala to wheat), GB (GM with biofertiliser; blue green algae to rice and Azotobacter sp. to wheat), GF (GM with FYM), GFB (GM with FYM and biofertiliser). Sodium hypochlorite (NaOCl)-resistant C correlated significantly with ammonium oxalate and dithionate extractable Fe, Al and Si in soil. The GFB showed the highest enrichment of SOC (32%) as well as NaOCl-resistant C (22%) at 0–15 cm soil depth. At higher soil depth, GM alone showed the highest enrichment of SOC (39% at 15–30 cm, 84% at 30–60 cm). The NaOCl-resistant C was higher in FYM and GFB treatments at 15–30 and 30–60 cm depths respectively. The proportion of NaOCl-resistant C to SOC increased down the profile and was highest (30–52%) in 30–60 cm soil depth. A multiple regression model developed between ammonium oxalate extractable Fe, Al and Si and SOC could well predict the stable SOC content. There was a substantial improvement in prediction when extractable Fe, Al and Si were combined together. Among the organic treatments, GFB showed the highest humification and aromaticity in humic acid with least polarity and more reduced form. The combination of all the organic sources (GFB) could be a promising nutrient management strategy for enhancing the stability of SOC in rice–wheat cropping systems of semiarid subtropical India.
Predicting soil carbon saturation deficit and related properties of New Zealand soils using infrared spectroscopy
Authors: Baldock J. A. , McNally S. R. , Beare M. H. , Curtin D. , Hawke B.
Published: October 2019

Conversion of soils supporting native vegetation to agricultural production has led to a loss of soil carbon stocks. Replacing a portion of the lost stocks will sequester atmospheric carbon with the concurrent benefit of enhancing soil sustainability. The ability of the fine fraction of soils (≤50-µm fraction) to adsorb organic carbon (OC) is considered a key mechanism capable of stabilising soil OC against loss. The difference between the current and maximum concentrations of OC in the soil fine fraction (FFC) has been termed the ‘saturation deficit’ (SatDef) and used to define the potential for a soil to sequester carbon. For New Zealand surface 0–15 cm soil layers, pedotransfer functions have been derived to quantify the soil carbon SatDef. The ability of combining infrared spectroscopy (IR) with partial least squares regression (PLSR) to derive predictive algorithms for soil properties included in these pedotransfer functions, the capacity of the soil fine fraction to stabilise carbon and the SatDef of the soil fine fraction were assessed in this study. A total of 168 air-dried and finely ground New Zealand surface soils representative of the major soil orders used for agricultural production were included. Principal components analysis of IR spectra showed a grouping by soil order that was related to mineralogy. Predictive IR/PLSR algorithms were derived for specific surface area, pyrophosphate-extractable aluminium, the FFC content, the 90th quantile regression of FFC and the SatDef of the fine fraction (R2 values ≥0.85; ratio of performance to interquartile range values ≥2.9). The results indicate that IR/PLSR provides a rapid and cost-effective mechanism for deriving information related to the amount of FFC in soils and the SatDef of the fine fraction. The IR/PLSR approach could be used to define the potential of soils to sequester carbon and identify the soil types to target for carbon sequestration technologies. The approach would also generate valuable data for soil carbon in national inventories or national soil condition monitoring programs.
Evidence for the reproduction of social class in brief speech
Authors: Kraus Michael W. , Torrez Brittany , Park Jun Won , Ghayebi Fariba
Published: October 2019

Significance

Social class mobility narratives pervade public consciousness in the United States, and yet patterns of actual mobility remain relatively constrained. This work examines how the tendency to accurately perceive the social class position of targets, by virtue of listening to their brief speech, can constrain economic mobility and perpetuate inequality. We find that Americans can perceive the social class of targets based on exposure to brief speech patterns, that word pronunciation facilitates this perceptual process, and that these cues bias hiring decisions in favor of those higher versus lower in social class. The findings suggest that social interaction patterns related to the perception of brief speech are potentially causal in the maintenance of economic inequality.
Simple framework for constructing functional spiking recurrent neural networks
Authors: Kim Robert , Li Yinghao , Sejnowski Terrence J.
Published: October 2019

Cortical microcircuits exhibit complex recurrent architectures that possess dynamically rich properties. The neurons that make up these microcircuits communicate mainly via discrete spikes, and it is not clear how spikes give rise to dynamics that can be used to perform computationally challenging tasks. In contrast, continuous models of rate-coding neurons can be trained to perform complex tasks. Here, we present a simple framework to construct biologically realistic spiking recurrent neural networks (RNNs) capable of learning a wide range of tasks. Our framework involves training a continuous-variable rate RNN with important biophysical constraints and transferring the learned dynamics and constraints to a spiking RNN in a one-to-one manner. The proposed framework introduces only 1 additional parameter to establish the equivalence between rate and spiking RNN models. We also study other model parameters related to the rate and spiking networks to optimize the one-to-one mapping. By establishing a close relationship between rate and spiking models, we demonstrate that spiking RNNs could be constructed to achieve similar performance as their counterpart continuous rate networks.
During infant maltreatment, stress targets hippocampus, but stress with mother present targets amygdala and social behavior
Authors: Raineki Charlis , Opendak Maya , Sarro Emma , Showler Ashleigh , Bui Kevin , McEwen Bruce S. , Wilson Donald A. , Sullivan Regina M.
Published: October 2019

Significance

Identifying the critical components of the complex infant experience within the nest that are necessary and sufficient to increase vulnerability to physical and mental disorders is a critical step toward the development of targeted interventions for neurobehavioral deficits observed in maltreated children. While it is generally believed that maternal behavior is correlated with infant outcomes, no assessment of the infant brain during caregiver-related maltreatment has been conducted to uncover causal factors. Here, we use animal models of maltreatment designed to build a bridge between human and animal literature. Our results suggest maltreatment-related social behavior and amygdala dysfunction require both an increase of the stress hormone corticosterone and the context of maternal presence, while hippocampal dysfunction depends only on increased corticosterone.
Repression of eEF2K transcription by NF-κB tunes translation elongation to inflammation and dsDNA-sensing
Authors: Bianco Christopher , Thompson Letitia , Mohr Ian
Published: October 2019

Significance

Following infection and inflammation, activation of the transcription factor NF-κB and stimulation of mRNA translation initiation remodel cellular gene expression. In contrast, how translation elongation factor 2, which performs the translocation step in protein synthesis, responds is not understood. We show that eEF2 Thr56 phosphorylation, which slows elongation, and eEF2 kinase (eEF2K) abundance are reduced by multiple NF-κB–activating stimuli. Significantly, NF-κB activation repressed eEF2K transcription to stimulate eEF2 by preventing eEF2 phosphorylation. In addition, eEF2K abundance regulates protein synthesis upon eEF2 inactivation by a bacterial toxin. This demonstrates how eEF2 is integrated into NF-κB innate immune response networks and reveals an unexpected mechanism whereby regulated nuclear transcription impacts translation elongation.
Atomic-level engineering and imaging of polypeptoid crystal lattices
Authors: Xuan Sunting , Jiang Xi , Spencer Ryan K. , Li Nan K. , Prendergast David , Balsara Nitash P. , Zuckermann Ronald N.
Published: October 2019

Significance

A fundamental challenge in materials science is to understand the atomic-level structures of nanoarchitectures assembled from synthetic polymers. Here, we report a family of sequence-defined polypeptoids that form free-floating crystalline 2-dimensional nanosheets, in which not only individual polymer chains and their relative orientations, but also atoms in nanosheets were directly observed by cryogenic transmission electron microscopy. These atomic details are inaccessible by conventional scattering techniques. Using the feedback between sequence-controlled synthesis and atomic imaging, we observed how the nanosheet structure responds to chemical modifications at the atomic-length scale. These atomic-level insights open the door to the design of bioinspired nanomaterials with more precisely controlled structures and properties.
Historical change of El Niño properties sheds light on future changes of extreme El Niño
Authors: Wang Bin , Luo Xiao , Yang Young-Min , Sun Weiyi , Cane Mark A. , Cai Wenju , Yeh Sang-Wook , Liu Jian
Published: October 2019

El Niño’s intensity change under anthropogenic warming is of great importance to society, yet current climate models’ projections remain largely uncertain. The current classification of El Niño does not distinguish the strong from the moderate El Niño events, making it difficult to project future change of El Niño’s intensity. Here we classify 33 El Niño events from 1901 to 2017 by cluster analysis of the onset and amplification processes, and the resultant 4 types of El Niño distinguish the strong from the moderate events and the onset from successive events. The 3 categories of El Niño onset exhibit distinct development mechanisms. We find El Niño onset regime has changed from eastern Pacific origin to western Pacific origin with more frequent occurrence of extreme events since the 1970s. This regime change is hypothesized to arise from a background warming in the western Pacific and the associated increased zonal and vertical sea-surface temperature (SST) gradients in the equatorial central Pacific, which reveals a controlling factor that could lead to increased extreme El Niño events in the future. The Coupled Model Intercomparison Project phase 5 (CMIP5) models’ projections demonstrate that both the frequency and intensity of the strong El Niño events will increase significantly if the projected central Pacific zonal SST gradients become enhanced. If the currently observed background changes continue under future anthropogenic forcing, more frequent strong El Niño events are anticipated. The models’ uncertainty in the projected equatorial zonal SST gradients, however, remains a major roadblock for faithful prediction of El Niño’s future changes.
Impact of a hydrophobic ion on the early stage of atmospheric aerosol formation
Authors: Feketeová Linda , Bertier Paul , Salbaing Thibaud , Azuma Toshiyuki , Calvo Florent , Farizon Bernadette , Farizon Michel , Märk Tilmann D.
Published: October 2019

Significance

Gas-to-particle conversion, also known as atmospheric aerosol nucleation, is responsible for about half of the global cloud condensation nuclei. It has been further argued that homogenous ternary nucleation including water is the major pathway for atmospheric aerosol formation. In contrast to earlier results on pure protonated water clusters, the shape of the measured velocity distributions of water molecules evaporated from excited water clusters doped with pyridinium, an abundant anthropogenic ion in the troposphere, shows evidence for out-of-equilibrium evaporation prior to thermalization. Water molecule evaporation is found to be much slower for the doped clusters, indicating in turn how such contaminants facilitate the growth of water clusters and consequently the nucleation processes at the early stages of atmospheric aerosol formation.
Assortative mixing and resource inequality enhance collective welfare in sharing networks
Authors: Shirado Hirokazu , Iosifidis George , Christakis Nicholas A.
Published: October 2019

Resource sharing can impose an economic trade-off: One person acquiring resources may mean that another cannot. However, if individuals value the social process itself that is a feature of economic exchanges, socio-structural manipulations might improve collective welfare. Using a series of online experiments with 600 subjects arrayed into 40 groups, we explore the welfare impact of 2 network interventions. We manipulated the degree assortativity of the groups (who were engaged in resource sharing) while keeping the number of people and connections fixed. Distinctly, we also manipulated the distribution of sharable resources by basing endowments on network degree. We show that structural manipulation (implementing degree assortativity) can facilitate the reciprocity that is achievable in exchanges and consequently affect group-level satisfaction. We also show that individuals are more satisfied with exchanges when each node is unequally endowed with resources that are proportional to the number of potential recipients, which again facilitates reciprocity. Collective welfare in settings involving resource sharing can be enhanced without the need for extra resources.
Shock, twofold dynamics, cascade
Authors: Depraz Natalie
Published: October 2019

Surprise is commonly seen as a sudden instantaneous, intensively emotional, exclamative interjective, bodily startling “shock”. I would like to show that it would better be also understood as a processual dynamics, which presupposes a deep transformation of its commonly taken-for-granted experiential meaning as a shock. Such a dynamics unfolds along multifarious vectors, exemplarily time, emotion, cognition, language, inter-subjectivity and body. Since I already focused elsewhere on four of these vectors of the dynamics of surprise, namely time, emotion, cognition and language, I will deal here with the bodily time of surprise and reveal how the latter cannot be reduced to startle but refers to a multifaceted generative embodied process.
Encoding surprise in English novels
Authors: Filippi-Deswelle Catherine
Published: October 2019

After studying surprise words of variable intensity, I presently turn to “mirative” clause constructions conveying surprise in the same type of literary corpus data in English, providing an enunciative treatment of characters as experiencers, not agents at first. Culioli’s T(P)EO defines surprise as the deconstruction of expectation in that the outcome of a situation is other than expected, valued positively or negatively according to the subjects’ norms. The linguistic encoding of surprise relates to prior subjective representations which the characters’ referents have to abandon when confronted with something new: unusual, unknown, or unthinkable. The communicative situation thus requires them to manage a certain otherness, necessitating some kind of agentive response in terms of adjustment to a new state of affairs.
How implicit is surprise?
Authors: Gerlain Audrey
Published: October 2019

As if it challenged the subject, surprise upsets somebody’s routine: it hastes one to realize how he usually thinks and acts, if it still fits with reality after that surprising event, even if he must create other ways of thinking and acting. Is surprise an experience that makes me aware of an implicit world which suddenly appears through a surprising event? Or, does surprise question that world as taken for granted, by constraining the subject to assess his implicit way of experiencing the world? Surprise is not always what happens in the underlying intentionality. In a practical sense, surprise is a kind of reality check: it urges to go back to reality. Describing the implicit intentionality in my lived experience, this paper aims at asking to what extent a surprising experience converges with the implicit world the subject takes for granted: firstly, thanks to a phenomenological approach of surprise as an implicit lived experience (Husserl, Schutz); secondly, by crossing that phenomenological description with a pragmatist approach (Dewey, Peirce), namely the radical Peirce’s thesis on surprise as a challenging experience; finally, by dealing with differences between phenomenology and pragmatism about the relation between emotion and cognition, subject’s self-control and passivity.
Looking at ‘unexpectedness’
Authors: Jugnet Anne , Lhôte Emilie
Published: October 2019

The nouns surprise and wonder have often been included in the subclass of potentially polysemous psych nouns, which can denote a psychological state and have a derived source reading. Our corpus-based analysis leads us to conclude that these nouns tend to refer to sources of surprise, and as such could rather be termed “source nouns” instead. First, we show that a metonymic link can be established between the primary source sense and the derived state sense of the nouns. We argue that this reversed link can be re-analysed as involving a synecdoche. We then look at the discourse functions of these nouns, notably at their role as “shell nouns”, which confirms our analysis of these nouns as characterizing sources of surprise.
Is surprise necessarily disappointing?
Authors: Serban Claudia
Published: October 2019

The article examines the function and status of surprise from Edmund Husserl’s phenomenological point of view on experience. Firstly, it is shown that, when experience is defined through concordance and continuity, it becomes difficult to describe surprise otherwise than as deception or disappointment. Secondly, the paper attempts to overcome this negative characterization of surprise without completely abandoning Husserl’s method and description. It is indeed shown that conflict is as important and irreducible as concordance and that experience should rather be defined, in a more dynamic manner, as the intertwining of both. The motivational link between the past and the future is then re-evaluated, in order to maintain a balance between the motivation of the past (expectation) and the open possibilities of the future (free anticipation). Thus, surprise can receive a legitimate and consistent place within experience, and a paradoxical expectation of surprise becomes conceivable.