bluuebunny/crossref_metadata_2025 huggingface dataset:
Recent Advances in the Generation of Nitrilium Betaine 1,3-Dipoles
Authors: Jamieson Craig , Livingstone Keith , Little Gemma
Published: February 2021

Nitrilium betaine 1,3-dipoles are ubiquitous reagents in organic chemistry, with applications ranging from natural product synthesis to materials science. Given the high reactivity of these zwitterionic motifs, they are invariably generated in situ from a suitable precursor, prior to use. This short review summarises the recent progress in the development of modern approaches towards the formation of these 1,3-dipoles, and their applications within a diverse range of fields.

1 Introduction

2 Nitrile Ylides

2.1 2H-Azirine Rearrangement

2.2 Addition of Nitriles to Carbenes

3 Nitrile Imines

3.1 2,5-Tetrazole Thermolysis

3.2 2,5-Tetrazole Photolysis

3.3 Diaryl Sydnone Photolysis

4 Nitrile Oxides

4.1 Hypervalent Iodine

4.2 The Nitroso Radical

4.3 Green Chemistry Approaches

4.4 Other Approaches

5 Conclusions
1,3-Bifunctional Nucleophilic Allylation Reagents: Preparative Methods and Synthetic Applications
Authors: Chen Ming , Liu Jiaming
Published: February 2021

1,3-Bifunctional nucleophilic allylation reagents play an important role in organic synthesis. In this short review, we summarize the methods for the preparation of 1,3-bifunctional reagents and their reactions with various electrophiles. Synthetic applications of these reagents in the context of complex molecule synthesis are also discussed.

1 Introduction

2 Reagent Synthesis

2.1 Symmetrical Reagents

2.2 Unsymmetrical Reagents

2.2.1 Bis-silane and Silyl-stannane Reagents

2.2.2 Bis-boron and Silyl-boron Reagents

3 Synthetic Applications

3.1 Allylation of Aldehydes

3.2 Allylation of Ketones

3.3 Allylation of Imines

3.4 Allylation of Other Electrophiles with 1,3-Bifunctional Allylation Reagents

4 Summary
Methods to determine the radiated power in SPI-mitigated disruptions in JET
Authors: Lovell J. , Reinke M. L. , Sheikh U. A. , Sweeney R. , Puglia P. , Carvalho P. , Baylor L. ,   JET Contributors
Published: February 2021

This paper presents techniques for evaluating the radiated power in JET disruptions. Disrupting plasmas are shown to have non-axisymmetric radiation profiles, motivating the re-evaluation of the standard techniques for calculating the total radiated power at JET using bolometry. Four single-channel bolometers at different toroidal locations are exploited to quantify the radiation asymmetry. Toroidal radiation peaking factors integrated over the entire disruption of up to 1.5 have been observed when varying the quantity of neon in pellets used in disruptions mitigated by shattered pellet injection. Using synthetic bolometer diagnostics developed with the Cherab spectroscopy modeling framework, we can estimate the systematic error on total power calculations for relevant radiation profiles and improve estimates of the total radiated power. We show that the component of the systematic error on the total power due to the poloidal radiation profile can be reduced from 70% to 10% with suitable assumptions about the structure of the poloidal profile.
Development of small high-voltage AC power supply for a dielectric barrier discharge plasma actuator
Authors: Suzuki Kento , Komuro Atsushi , Sato Shintaro , Sakurai Mahoro , Mitsuhashi Kodai , Sekiya Natsuko , Watanabe Yayoi , Kanagawa Keito , Ando Akira
Published: February 2021

A dielectric-barrier discharge plasma actuator (DBDPA) is a promising flow control device that can prevent flow separation around an airfoil using electrical discharges. Miniaturizing the DBDPA power supply remains a crucial technological challenge because its size and weight determine the performance of fluid devices equipped with this type of actuator. In this study, we propose a compact high-voltage AC power supply for a DBDPA intended for installation on small airplanes, including unmanned aerial vehicles. The power supply, which consists of a power supply board, a main control board, and a DC/AC converter board, is ∼110 g in weight. It can drive a 300-mm long DBDPA without any substantial voltage drop. The power consumption in standby remains below 1 W, and the maximum consumption during discharge in burst mode at a burst ratio of 5% is 24 W. The power supply uses a lithium-ion battery with a capacity of 1800 mA h, which allows continuous DBDPA operation for ∼1.5 h. An experiment was conducted in a wind tunnel using an airfoil model whose cross-section corresponds to that of an airfoil from a commercial glider airplane. Experimental results reveal that the surface pressure around the airfoil is modified by DBDPA operation, clearly demonstrating the effectiveness of the developed power supply for operating a DBDPA as a flow control device. The size and weight of the proposed power supply can be established as a benchmark to further miniaturize and optimize DBDPA power supplies.
Multi-variable classification model for valve internal leakage based on acoustic emission time–frequency domain characteristics and random forest
Authors: Ye Guo-Yang , Xu Ke-Jun , Wu Wen-Kai
Published: February 2021

To use acoustic-emission technology to detect leaks inside valves, the necessary first step is to model the valve-internal-leakage acoustic-emission signal (VILAES) mathematically. A multi-variable classification model that relates the VILAES characteristics and the leakage rate under varying pressure is built by combining time–frequency domain characteristics and the random-forest method. A Butterworth bandpass filter is used to preprocess the VILAES from a liquid medium, and the best frequency band for filtering is determined as being 140 kHz–180 kHz. Then, (i) the standard deviation, (ii) root mean square, (iii) wavelet packet entropy, (iv) peak standard-deviation probability density, and (v) spectrum area are calculated as the VILAES characteristics, and six parameters—the pressure and the five VILAES characteristics—are used as the inputs for the random-forest classification model. Analysis shows that the five VILAES characteristics increase with an increase in the leakage rate. The multi-variable classification model is established by random forest to determine whether the valve leakage is small, medium, or large. The random forest uses many decision trees to predict the final result. For the same experimental data, the accuracy and operating time of the multi-variable classification model are compared with those of a support-vector-machine classification method for the bandpass and wavelet packet filtering preprocessing methods. The results show that the modeling method based on the combination of time–frequency characteristics and random forest has shorter operating time and higher accuracy.
Formulation of 8-moment plasma transport with application to the Nernst effect
Authors: Hamilton Jason , Seyler Charles E.
Published: February 2021

8-moment plasma models using two different distribution functions are used to study the Nernst effect and heat transport in dense plasma. These models are presented in hyperbolic form in contrast to traditional parabolic systems derived from perturbing the distribution function, as in Braginskii [Rev. Plasma Phys. 1, 205 (1965)]. The hyperbolic moment formulation can be solved implicitly in time with straightforward and fast local solvers. The numerical implementation of 8-moment models with the relaxation method in the PERSEUS code is also presented. To test 8-moment PERSEUS compared to Braginskii's transport equations, a verification test for the Nernst thermo-magnetic wave by Velikovich et al. [Phys. Plasmas 26, 112702 (2019)] is performed that confirms the presence of the same physics, but with slight differences in the transport coefficients, which are tabulated in the limits of high and low magnetization.
Marangoni-driven instability patterns of an N-hexadecane drop triggered by assistant solvent
Authors: Zhao Wenjing , Ma Hongzhi , Ji Wenjie , Li Weibin , Wang Jin , Yuan Quanzi , Wang Yuren , Lan Ding
Published: February 2021

Flows of thin fluid layers spreading, which have a distinguished history, have been studied since the days of Reynolds, who was among the early researchers to examine flows. Different from surfactant-driven spreading, which is currently the most common subject of study, we observe the spreading process of n-hexadecane driven by volatile silicone oil at the surface of the aqueous substrates and explore the influence of Marangoni flow caused by surface tension gradient on liquid-driven spreading. We find that on different substrates, the initial state of n-hexadecane is different, and there are two instability patterns during the spreading, subsequently, which are analyzed theoretically. While the n-hexadecane drop stationed on the liquid surface is small, it is driven to form a rim and then breaks up into beads, which shows the Rayleigh–Plateau instability patterns. When we put the n-hexadecane drop on the surface of the saturated sodium chloride solution, which spreads out more, it is driven to form a circular belt first and fingering instability subsequently occurs at the inner edge of the circular belt.
Dynamics of filaments during the edge-localized mode crash on NSTX
Authors: Lampert M. , Diallo A. , Myra J. R. , Zweben S. J.
Published: February 2021

Edge localized modes (ELMs) are routinely observed in H-mode plasma regimes of the National Spherical Torus Experiment (NSTX). Due to the explosive nature of the instability, only diagnostics with high temporal and spatial resolution could provide a detailed insight into the dynamics associated with the ELMs. Gas-puff imaging at NSTX provides 2D measurements of the magnetic field aligned fluctuations (e.g., ELM filaments) in the scrape-off layer and at the plasma edge with 2.5 μs temporal and 10 mm optical resolution. A novel analysis technique was developed to estimate the frame-by-frame velocities and the spatial parameters of the dominant structures associated with the ELMs. The analysis was applied to single ELM events to characterize the ELM crash dynamics and then extended to a database of 159 ELM events. Statistical analysis was performed in order to find the characterizing dynamics of the ELM crash. The results show that on average, an ELM crash consists of a filament with a circular cross section, which is propelled outward with a characterizing peak radial velocity of ∼3.3 km/s. The radial velocity was found to be linearly dependent on the distance of the filament from the separatrix, which has never been seen before. The ELM filament is characterized by propagation in the ion-diamagnetic direction poloidally with a peak velocity of 11.4 km/s. The ELM crash lasts for approximately 100 μs until the radial propulsion settles back to the pre-ELM level. The experimental findings were compared with analytical theory. Two possible mechanisms were identified for explaining the observations: the curvature interchange model and the current–filament interaction model.
Nonadiabatic phenomena in molecular vibrational polaritons
Authors: Szidarovszky Tamás , Badankó Péter , Halász Gábor J. , Vibók Ágnes
Published: February 2021

Nonadiabatic phenomena are investigated in the rovibrational motion of molecules confined in an infrared cavity. Conical intersections (CIs) between vibrational polaritons, similar to CIs between electronic polaritonic surfaces, are found. The spectral, topological, and dynamic properties of the vibrational polaritons show clear fingerprints of nonadiabatic couplings between molecular vibration, rotation, and the cavity photonic mode. Furthermore, it is found that for the investigated system, composed of two rovibrating HCl molecules and the cavity mode, breaking the molecular permutational symmetry, by changing   35Cl to   37Cl in one of the HCl molecules, the polaritonic surfaces, nonadiabatic couplings, and related spectral, topological, and dynamic properties can deviate substantially. This implies that the natural occurrence of different molecular isotopologues needs to be considered when modeling realistic polaritonic systems.
Three-dimensional phononic crystal with ultra-wide bandgap at megahertz frequencies
Authors: Iglesias Martínez Julio Andrés , Moughames Johnny , Ulliac Gwenn , Kadic Muamer , Laude Vincent
Published: February 2021

Phononic crystals have attracted wide attention in diverse scientific communities due to their ability to efficiently reflect, focus, and guide acoustic and elastic waves. Their use in ultrasonic applications such as medical imaging, however, remains elusive since three-dimensional phononic crystals with lattice constants in the range of hundreds of micrometers are required to operate with MHz ultrasound, smaller than what most additive manufacturing solutions can provide. This work presents a three-dimensional phononic crystal with a cubic symmetry having an experimental ultra-wide complete bandgap extending from 0.6 MHz to 7.5 MHz. Crystal specimens are manufactured using two-photon lithography at the microscale, with a lattice constant of 300 μm, and are characterized using heterodyne interferometry.
Direct observation of negative differential resistance in WS2 homojunction
Authors: Hsu Bo , Farid Sidra , Almazan Justino , Stroscio Michael. A. , Dutta Mitra
Published: February 2021

Vertical tunneling junctions showing negative differential resistance (NDR) are realized in WS2 homojunction devices. Mono-/multilayered single crystalline WS2 is grown using chemical vapor deposition. NDR is observed through resonant tunneling in Au/bi-layer WS2/Au and Pt/few-layered WS2/Au tunneling junctions by back-gating at room temperature. While two-dimensional materials have been a central focus of materials research during the past decade, exploiting novel properties in diverse layers of these materials is emerging with new designs for electronic devices. Our results pave the way for novel resonant tunneling devices presenting a route to fabricate homojunction WS2 with simple fabrication techniques.
A periodic equation-of-motion coupled-cluster implementation applied to F-centers in alkaline earth oxides
Authors: Gallo Alejandro , Hummel Felix , Irmler Andreas , Grüneis Andreas
Published: February 2021

We present an implementation of the equation of motion coupled-cluster singles and doubles (EOM-CCSD) theory using periodic boundary conditions and a plane wave basis set. Our implementation of EOM-CCSD theory is applied to study F-centers in alkaline earth oxides employing a periodic supercell approach. The convergence of the calculated electronic excitation energies for neutral color centers in MgO, CaO, and SrO crystals with respect to the orbital basis set and system size is explored. We discuss extrapolation techniques that approximate excitation energies in the complete basis set limit and reduce finite size errors. Our findings demonstrate that EOM-CCSD theory can predict optical absorption energies of F-centers in good agreement with experiment. Furthermore, we discuss calculated emission energies corresponding to the decay from triplet to singlet states responsible for the photoluminescence properties. Our findings are compared to experimental and theoretical results available in the literature.
Electric-polarization-driven magnetic phase transition in a ferroelectric–ferromagnetic heterostructure
Authors: Feng Dier , Zhu Ziye , Chen Xiaofang , Qi Jingshan
Published: February 2021

Magnetoelectric coupling is of great interest recently to both understand the fundamental physics and device applications. Materials with strong magnetoelectric coupling, high Curie temperature, and large electric polarization are still rare. We suggest a heterostructure that combines the known memory effect of the switchable ferroelectric In2Se3 [Adv. Funct. Mater. 2019, 29, 1808606] with a van der Waals bonded two-dimensional (2D) metal-organic framework (MOF) film. The magnetic ground state of this MOF can be changed from an antiferromagnetic state to a ferromagnetic through hole-doping. We use first-principles calculations to show that in such a heterostructure, adequate doping differences to cause this phase transition are expected from the changes in the interfacial charge transfer between the MOF and In2Se3 when the polarization direction of the In2Se3 is reversed. This and similar 2D heterostructures may, therefore, provide both a fascinating material platform for understanding the fundamental physics of magnetoelectric coupling and a strategy for designing spin-current-based nonvolatile memory structures.
Quantum hydrodynamic theory of quantum fluctuations in dipolar Bose–Einstein condensate
Authors: Andreev Pavel A.
Published: February 2021

Traditional quantum hydrodynamics of Bose–Einstein condensates (BECs) is restricted by the continuity and Euler equations. The quantum Bohm potential (the quantum part of the momentum flux) has a nontrivial part that can evolve under quantum fluctuations. The quantum fluctuations are the effect of the appearance of particles in the excited states during the evolution of BEC mainly consisting of the particles in the quantum state with the lowest energy. To cover this phenomenon in terms of hydrodynamic methods, we need to derive equations for the momentum flux and the current of the momentum flux. The current of the momentum flux evolution equation contains the interaction leading to the quantum fluctuations. In the dipolar BECs, we deal with the long-range interaction. Its contribution is proportional to the average macroscopic potential of the dipole–dipole interaction (DDI) appearing in the mean-field regime. The current of the momentum flux evolution equation contains the third derivative of this potential. It is responsible for the dipolar part of quantum fluctuations. Higher derivatives correspond to the small scale contributions of the DDI. The quantum fluctuations lead to the existence of the second wave solution. The quantum fluctuations introduce the instability of the BECs. If the dipole–dipole interaction is attractive, but being smaller than the repulsive short-range interaction presented by the first interaction constant, there is the long-wavelength instability. There is a more complex picture for the repulsive DDI. There is the small area with the long-wavelength instability that transits into a stability interval where two waves exist.
Simplified Josephson-junction fabrication process for reproducibly high-performance superconducting qubits
Authors: Osman A. , Simon J. , Bengtsson A. , Kosen S. , Krantz P. , P. Lozano D. , Scigliuzzo M. , Delsing P. , Bylander Jonas , Fadavi Roudsari A.
Published: February 2021

We introduce a simplified fabrication technique for Josephson junctions and demonstrate superconducting Xmon qubits with T1 relaxation times averaging above 50 μs (Q>1.5×106). Current shadow-evaporation techniques for aluminum-based Josephson junctions require a separate lithography step to deposit a patch that makes a galvanic, superconducting connection between the junction electrodes and the circuit wiring layer. The patch connection eliminates parasitic junctions, which otherwise contribute significantly to dielectric loss. In our patch-integrated cross-type junction technique, we use one lithography step and one vacuum cycle to evaporate both the junction electrodes and the patch. This eliminates a key bottleneck in manufacturing superconducting qubits by reducing the fabrication time and cost. In a study of more than 3600 junctions, we show an average resistance variation of 3.7% on a wafer that contains forty 0.5×0.5-cm2 chips, with junction areas ranging between 0.01 and 0.16 μm2. The average on-chip spread in resistance is 2.7%, with 20 chips varying between 1.4% and 2%. For the junction sizes used for transmon qubits, we deduce a wafer-level transition-frequency variation of 1.7%–2.5%. We show that 60%–70% of this variation is attributed to junction-area fluctuations, while the rest is caused by tunnel-junction inhomogeneity. Such high frequency predictability is a requirement for scaling-up the number of qubits in a quantum computer.
Reversible heat production during electric double layer buildup depends sensitively on the electrolyte and its reservoir
Authors: Glatzel Fabian , Janssen Mathijs , Härtel Andreas
Published: February 2021

Several modern technologies for energy storage and conversion are based on the screening of electric charge on the surface of porous electrodes by ions in an adjacent electrolyte. This so-called electric double layer (EDL) exhibits an intricate interplay with the electrolyte’s temperature that was the focus of several recent studies. In one of them, Janssen et al. [Phys. Rev. Lett. 119, 166002 (2017)] experimentally determined the ratio Qrev/Wel of reversible heat flowing into a supercapacitor during an isothermal charging process and the electric work applied therein. To rationalize that data, here, we determine Qrev/Wel within different models of the EDL using theoretical approaches such as density functional theory (DFT) as well as molecular dynamics simulations. Applying mainly the restricted primitive model, we find quantitative support for a speculation of Janssen et al. that steric ion interactions are key to the ratio Qrev/Wel. Here, we identified the entropic contribution of certain DFT functionals, which grants direct access to the reversible heat. We further demonstrate how Qrev/Wel changes when calculated in different thermodynamic ensembles and processes. We show that the experiments of Janssen et al. are explained best by a charging process at fixed bulk density or in a “semi-canonical” system. Finally, we find that Qrev/Wel significantly depends on parameters such as pore and ion size, salt concentration, and valencies of the cations and anions of the electrolyte. Our findings can guide further heat production measurements and can be applied in studies on, for instance, nervous conduction, where reversible heat is a key element.
On discrete Lorenz-like attractors
Authors: Gonchenko Sergey , Gonchenko Alexander , Kazakov Alexey , Samylina Evgeniya
Published: February 2021

We study geometrical and dynamical properties of the so-called discrete Lorenz-like attractors. We show that such robustly chaotic (pseudohyperbolic) attractors can appear as a result of universal bifurcation scenarios, for which we give a phenomenological description and demonstrate certain examples of their implementation in one-parameter families of three-dimensional Hénon-like maps. We pay special attention to such scenarios that can lead to period-2 Lorenz-like attractors. These attractors have very interesting dynamical properties and we show that their crises can lead, in turn, to the emergence of discrete Lorenz shape attractors of new types.
Improved room-temperature magnetoelectric effect and crystal structure in polycrystalline BaSrCo2Fe11AlO22
Authors: Hirose Sakyo , Urushihara Daisuke , Asaka Toru , Kimura Tsuyoshi
Published: February 2021

The crystal structure and the magnetoelectric (ME) effect were investigated in highly c-axis oriented polycrystalline samples of Y-type hexaferrite, BaSrCo2Fe11AlO22, fabricated using a rotating magnetic field. A detailed crystal structure was determined using a combination of scanning transmission electron microscopy and single crystal x-ray diffraction. It was revealed that Co and Al ions, which play important roles in the performance of the ME effect, reside mainly on the Fe site in the S block of the Y-type hexaferrite. In the oriented samples, electric polarization induced by applying a magnetic field reached 140 μC/m2 at 200 K and 51 μC/m2 at 300 K; consequently, the ME coefficient αH was estimated to be 7200 ps/m at 300 K. The ME performance of the oriented samples is superior to that of nonoriented polycrystalline samples and comparable with that of single crystals. Furthermore, the oriented samples allow the control of magnetization by an electric field up to 325 K. These results facilitate further investigations on room-temperature multiferroics and their practical applications.
Acoustic radiation of MEMS and NEMS resonators in fluids
Authors: Liem Alyssa T. , Ti Chaoyang , Kara Vural , Ari Atakan B. , McDaniel J. Gregory , Ekinci Kamil L.
Published: February 2021

Here, we study the acoustic radiation generated by the vibration of miniaturized doubly clamped and cantilever beam resonators in viscous fluids. Acoustic radiation results in an increase in dissipation and consequently a decrease in the resonator’s quality factor. We find that dissipation due to acoustic radiation is negligible when the acoustic wavelength in the fluid is much larger than the bending wavelength. In this regime, dissipation is primarily due to the viscous losses in the fluid and may be predicted with the two-dimensional cylinder approximation in the absence of axial flow and substrate effects. In contrast, when the bending wavelength approaches the length of the acoustic wavelength, acoustic radiation becomes prominent. In this regime, dissipation due to acoustic radiation can no longer be neglected, and the cylinder approximation inaccurately characterizes the total energy loss in the system. Experiments are performed with microcantilevers of varying lengths in Ar and N2 to observe trends in the acoustic wavelength of the fluid and bending wavelength. Additional experimental results from doubly clamped nanoelectromechanical system beams are also presented. Experimental results illustrate an increase in dissipation, which is further analyzed with the use of three-dimensional finite element models. With the numerical simulations, we calculate the radiation efficiency of the measured devices and analyze the pressure fields generated by the vibrating resonators. This analysis allows one to estimate the effects of acoustic radiation for any resonator.
Time-dependent momentum expectation values from different quantum probability and flux densities
Authors: Schaupp Thomas , Renziehausen Klaus , Barth Ingo , Engel Volker
Published: February 2021

Based on the Ehrenfest theorem, the time-dependent expectation value of a momentum operator can be evaluated equivalently in two ways. The integrals appearing in the expressions are taken over two different functions. In one case, the integrand is the quantum mechanical flux density j̲, and in the other, a different quantity j̲̃ appears, which also has the units of a flux density. The quantum flux density j̲ is related to the probability density ρ via the continuity equation, and j̲̃ may as well be used to define a density ρ̃ that fulfills a continuity equation. Employing a model for the coupled dynamics of an electron and a proton, we document the properties of the densities and flux densities. It is shown that although the mean momentum derived from the two quantities is identical, the various functions exhibit a very different coordinate and time-dependence. In particular, it is found that the flux density j̲̃ directly monitors temporal changes in the probability density, and the density ρ̃ carries information about wave packet dispersion occurring in different spatial directions.
Photoelectrochemical investigation of charge injection efficiency for quantum dot light-emitting diode
Authors: Kitano Keisuke , Sakakibara Yusuke , Kago Masashi , Doe Takahiro , Ueda Masaya , Ryowa Tatsuya , Izumi Makoto , Nishi Hiroyasu , Tatsuma Tetsu , Arakawa Yasuhiko
Published: February 2021

When we applied colloidal quantum dots (QDs) for quantum dot light emitting diodes, it was well known that shell thickness played an important role in core protection, confinement of electrons and holes, and charge injection efficiency. However, although the shell thickness dependence of electroluminescence properties was reported, carrier injection efficiency has not been discussed in detail. In this paper, we investigated the effect of shell thickness on the carrier injection efficiency that was evaluated by photoelectrochemical measurements. By comparing the product of internal quantum yield of photoluminescence and the evaluated carrier injection efficiency with external quantum efficiency (EQE) for QDs with various shell thicknesses, we found that the optimal shell thickness for increasing EQE is determined by the balance between protection of QD's surface and carrier injection efficiency.
Can extension programs improve grazing management in rangelands: a case study in Australia
Authors: Rolfe John , Star Megan , Curcio Adam
Published: February 2021

A key challenge in reducing sediment moving from grazing lands into the Great Barrier Reef in Australia is to encourage beef cattle producers to improve management practices. Excessive grazing pressures cause land degradation, leading to both increased sediment runoff and lower future profits. Although higher grazing rates may be possible (and profitable) in better seasons, slow rates of adjustment to poorer seasons can lead to overgrazing and negative impacts on land condition. For policymakers the challenge is to find mechanisms that encourage or signal producers to be more precise in their management and avoid overstocking. Some of the most common options include extension programs, grant programs that use financial incentives, and regulation.
In this paper we outline a conceptual framework that shows why extension may be a more powerful driver of management change than incentive programs, and then test this through an evaluation of a case study program conducted with beef cattle producers in catchments of the Great Barrier Reef, Australia. The pathway involving landholders to implement management change was through improved efficiency and productivity, as these are the issues that drive ongoing participation in broader environmental programs.
The results present multiple lines of evidence to infer positive outcomes of an extension program in terms of changed management practices, which may be expected to generate improved productivity and better water quality outcomes. These can be grouped into three key areas. First, outcomes show positive improvement relative to the Grazing Water Quality Risk framework for the Great Barrier Reef catchments, which is designed to assess the links between land management and water quality. This indicates that resource condition is likely to improve and sediment emissions should be reduced over time. A second outcome is increased landholder engagement and improved understanding of their business and engagement in future programs, which should underpin ongoing adoption. A third outcome is improved management of risk and developing the skills to do this through data collection and monitoring, which should improve management responses in drought years.
Soil organic carbon sequestration potential of Pampean soils: comparing methods and estimation for surface and deep layers
Authors: Alvarez Roberto , Berhongaray Gonzalo
Published: February 2021

Estimates of soil carbon sequestration potential can help identify areas where appropriate use and management practices can be applied to convert them into carbon sinks. We estimated the carbon capacity of Pampean soils using previously developed models and compared the results with a local model developed by simultaneous quantile regression. We also modelled the effects of the factors controlling the carbon saturation deficit using artificial neural networks and mapped the topsoil and subsoil saturation deficit of the region. Data from a soil survey, in which 296 sites were sampled to 1 m depth, were used. Paired sites in grassland, cropland and lowland areas were selected. The total organic carbon was measured, and the proportion stabilised in the clay + silt (<20 µm) fraction was estimated. The saturation deficit could be predicted (R2 = 0.78) by neural networks and was greater in cropland, followed by lowland and then grassland. It was higher in fine textured soils, in soil surface layers and in humid and colder environments. The saturation deficit of the region is 8.8 Gt carbon (average 196 Mg C ha–1), approximately double the current organic carbon content of the region, indicating that there is considerable room for carbon sequestration in the Pampas. Efforts to increase soil carbon levels must focus on the finely textured soils in the humid part of the region.
The genomics of ecological flexibility, large brains, and long lives in capuchin monkeys revealed with fecalFACS
Authors: Orkin Joseph D. , Montague Michael J. , Tejada-Martinez Daniela , de Manuel Marc , del Campo Javier , Cheves Hernandez Saul , Di Fiore Anthony , Fontsere Claudia , Hodgson Jason A. , Janiak Mareike C. , Kuderna Lukas F. K. , Lizano Esther , Martin Maria Pia , Niimura Yoshihito , Perry George H. , Valverde Carmen Soto , Tang Jia , Warren Wesley C. , de Magalhães João Pedro , Kawamura Shoji , Marquès-Bonet Tomàs , Krawetz Roman , Melin Amanda D.
Published: February 2021

Significance

Surviving challenging environments, living long lives, and engaging in complex cognitive processes are hallmark human characteristics. Similar traits have evolved in parallel in capuchin monkeys, but their genetic underpinnings remain unexplored. We developed and annotated a reference assembly for white-faced capuchin monkeys to explore the evolution of these phenotypes. By comparing populations of capuchins inhabiting rainforest versus dry forests with seasonal droughts, we detected selection in genes associated with kidney function, muscular wasting, and metabolism, suggesting adaptation to periodic resource scarcity. When comparing capuchins to other mammals, we identified evidence of selection in multiple genes implicated in longevity and brain development. Our research was facilitated by our method to generate high- and low-coverage genomes from noninvasive biomaterials.
Political persuasion in a Spanish electoral debate
Authors: Hidalgo Downing Raquel , Nieto y Otero María Jesús
Published: February 2021

In this paper, we study the elements of political discourse where persuasion is present as communicative strategy. In particular, we focus on the analysis of intonation and affectivity in a two-candidate Spanish electoral debate (Hidalgo Downing and Nieto y Otero 2014;Ponsonnet 2014;Reber 2012).The methodology consisted in selecting the openings and closings of each turn, taking the act as analysis unit (Briz 2003); for the acoustic analysis we have examined three parameters – fundamental frequency, intensity and vowel durations –, and four strategies for the positive affective bonds: assertiveness, inclusion, specificity and naturalization, in order to pursue the initial hypothesis on whether it is possible to find relations between intonation and affectivity. The analysis shows that both candidates use affective bonds and intonation to enhance persuasion, although there are interesting differences between candidates and between openings and closings. While openings show greater number and variety of strategies, both verbal and intonational, closings show lower intonational contours and less variation, therefore openings showing higher use of positive persuasive strategies, whereas in closings, there are no strategies addressed to the hearer, the most frequent being assertiveness. As for intonational contours, there is a general lowering in all values.
Environmental pollution and perturbations.
Authors: Rees Paul A.
Published: February 2021

This chapter contains questions about the pollution of air, land and water (and its effect on food chains), environmental damage and disturbance and major environmental disasters.
Environmental assessment, monitoring and modelling.
Authors: Rees Paul A.
Published: February 2021

This chapter contains questions about the equipment and methods used to conduct environmental assessments, monitor biodiversity and model ecological systems.
Analysis of the TORC1 interactome reveals a spatially distinct function of TORC1 in mRNP complexes
Authors: Chang Yeonji , Lim Gyubum , Huh Won-Ki
Published: February 2021

The target of rapamycin complex 1 (TORC1) is mainly localized to the vacuolar membrane and regulates eukaryotic cell growth in response to nutrient availability. To obtain deeper insights into the functional roles of TORC1, we performed a genome-wide analysis of the TORC1 interactome in yeast using the bimolecular fluorescence complementation (BiFC) assay. We found that while most of the BiFC signals are observed at the vacuolar membrane, a fraction of them are detected at cytoplasmic messenger ribonucleoprotein (mRNP) granules. Moreover, mRNA-binding proteins are enriched in the TORC1 interactome, suggesting a functional relationship between TORC1 and mRNA metabolism. We show that a portion of TORC1 is consistently associated with mRNP complexes and interacts with a specific subset of mRNAs. We also demonstrate that TORC1 directly targets a translational repressor Scd6 and that the activity of Scd6 is inhibited by TORC1-dependent phosphorylation. Collectively, our data suggest that TORC1 plays a novel role in posttranscriptional regulation by controlling the activity of Scd6.
Truly epigenetic: A centromere finds a “neo” home
Authors: Carty Ben L. , Dunleavy Elaine M.
Published: February 2021

Murillo-Pineda and colleagues (2021. J. Cell Biol.https://doi.org/10.1083/jcb.202007210) use CRISPR-Cas9–based genetic engineering in human cells to induce a new functional centromere at a naive chromosomal site. Long-read DNA sequencing at the neocentromere provides firm evidence that centromere establishment is a truly epigenetic event.
Convergent evolutionary pathways toward energy saving in muscle?
Authors: Reconditi Massimo
Published: February 2021

Reconditi reviews research into the role temperature plays on motor disorders.
Bulk viscosity in relativistic fluids: from thermodynamics to hydrodynamics
Authors: Gavassino L , Antonelli M , Haskell B
Published: February 2021

The approach of extended irreversible thermodynamics consists of promoting the dissipative fluxes to non-equilibrium thermodynamic variables. In a relativistic context, this naturally leads to the formulation of the theory of Israel and Stewart (1979), which is, to date, one of the most successful theories for relativistic dissipation. Although the generality of the principle makes it applicable to any dissipative fluid, a connection of the Israel–Stewart theory with microphysics has been established, through kinetic theory, only for the case of ideal quantum gases. By performing a convenient change of variables, we provide, for the case of bulk viscosity, an equivalent reformulation of the equations at the basis of extended irreversible thermodynamics. This approach maps any thermodynamic process which contributes to the bulk viscosity into a set of chemical reactions, whose reaction coordinates are abstract parameters describing the displacement from local thermodynamic equilibrium of the fluid element. We apply our new formalism to the case of the relativistic fluids, showing that the Israel–Stewart model for bulk viscosity is just the second-order expansion of a minimal model belonging to a larger class of non-perturbative theories for bulk viscosity which include the nuclear-reaction-mediated bulk viscosity of neutron star matter as a particular case. Furthermore, we show with concrete examples that our formalism provides new ways of computing the bulk viscosity directly and defines a simple prescription for constructing the Israel–Stewart model for a generic bulk-viscous fluid.
The effect of capacitance on high-efficiency photovoltaic modules: a review of testing methods and related uncertainties
Authors: Pravettoni Mauro , Poh Daren , Prakash Singh Jai , Wei Ho Jian , Nakayashiki Kenta
Published: February 2021

The effect of solar cell capacitance in the electrical characterization of photovoltaic (PV) modules at Standard Test Conditions (STC) is known since the 1990s. With the efficiency of solar modules increasing in the years, the corresponding measurement artefact has been generally resolved with long pulse simulators, from few milliseconds in the 2000 s and up to hundred milliseconds nowadays. With the last improvements in module technology, with the growing interest in n-type silicon and silicon heterojunction, and with the increasing wafer and cell sizes, it is demonstrated that even 100 ms simulators are no longer enough for accurate direct I–V measurements. The need for continuous simulators is therefore becoming more frequent even for accurate measurement of commercial size modules. This work summarizes the basic physics behind the effect of capacitance on the electrical characterization of silicon PV modules, with the simplest approach of a single diode capacitive model and with examples from high efficiency modules commercially available. It reviews eight measurement methods to mitigate the effect for accurate electrical characterization at STC; finally, it presents a novel and comprehensive analysis of the uncertainty contribution to the maximum power and open-circuit voltage determination of these measurement methods. The paper is a review of the best practices in advanced testing laboratories of silicon PV modules nowadays, and it represents a contribution addressed to metrologists, researchers and module manufacturers.
Fabrication of single-nanometer metallic gaps via spontaneous nanoscale dewetting
Authors: Zeng Pei , Shu Zhiwen , Zhang Shi , Liang Huikang , Zhou Yuting , Ba Dedong , Feng Zhanzu , Zheng Mengjie , Wu Jianhui , Chen Yiqin , Duan Huigao
Published: February 2021

Ultrasmall metallic nanogaps are of great significance for wide applications in various nanodevices. However, it is challenging to fabricate ultrasmall metallic nanogaps by using common lithographic methods due to the limited resolution. In this work, we establish an effective approach for successful formation of ultrasmall metallic nanogaps based on the spontaneous nanoscale dewetting effect during metal deposition. By varying the initial opening size of the exposed resist template, the influence of dewetting behavior could be adjusted and tiny metallic nanogaps can be obtained. We demonstrate that this method is effective to fabricate diverse sub-10 nm gaps in silver nanostructures. Based on this fabrication concept, even sub-5 nm metallic gaps were obtained. SERS measurements were performed to show the molecular detection capability of the fabricated Ag nanogaps. This approach is a promising candidate for sub-10 nm metallic gaps fabrication, thus possessing potential applications in nanoelectronics, nanoplasmonics, and nano-optoelectronics.
A comparison of methods for fully automatic segmentation of tumors and involved nodes in PET/CT of head and neck cancers
Authors: Groendahl Aurora Rosvoll , Skjei Knudtsen Ingerid , Huynh Bao Ngoc , Mulstad Martine , Moe Yngve Mardal , Knuth Franziska , Tomic Oliver , Indahl Ulf Geir , Torheim Turid , Dale Einar , Malinen Eirik , Futsaether Cecilia Marie
Published: February 2021

Target volume delineation is a vital but time-consuming and challenging part of radiotherapy, where the goal is to deliver sufficient dose to the target while reducing risks of side effects. For head and neck cancer (HNC) this is complicated by the complex anatomy of the head and neck region and the proximity of target volumes to organs at risk. The purpose of this study was to compare and evaluate conventional PET thresholding methods, six classical machine learning algorithms and a 2D U-Net convolutional neural network (CNN) for automatic gross tumor volume (GTV) segmentation of HNC in PET/CT images. For the latter two approaches the impact of single versus multimodality input on segmentation quality was also assessed. 197 patients were included in the study. The cohort was split into training and test sets (157 and 40 patients, respectively). Five-fold cross-validation was used on the training set for model comparison and selection. Manual GTV delineations represented the ground truth. Tresholding, classical machine learning and CNN segmentation models were ranked separately according to the cross-validation Sørensen–Dice similarity coefficient (Dice). PET thresholding gave a maximum mean Dice of 0.62, whereas classical machine learning resulted in maximum mean Dice scores of 0.24 (CT) and 0.66 (PET; PET/CT). CNN models obtained maximum mean Dice scores of 0.66 (CT), 0.68 (PET) and 0.74 (PET/CT). The difference in cross-validation Dice between multimodality PET/CT and single modality CNN models was significant (p ≤ 0.0001). The top-ranked PET/CT-based CNN model outperformed the best-performing thresholding and classical machine learning models, giving significantly better segmentations in terms of cross-validation and test set Dice, true positive rate, positive predictive value and surface distance-based metrics (p ≤ 0.0001). Thus, deep learning based on multimodality PET/CT input resulted in superior target coverage and less inclusion of surrounding normal tissue.
Al2O3:C optically stimulated luminescence dosimeters (OSLDs) for ultra-high dose rate proton dosimetry
Authors: Christensen Jeppe Brage , Togno Michele , Nesteruk Konrad Pawel , Psoroulas Serena , Meer David , Weber Damien Charles , Lomax Tony , Yukihara Eduardo G , Safai Sairos
Published: February 2021

The response of Al2O3:C optically stimulated luminescence detectors (OSLDs) was investigated in a 250 MeV pencil proton beam. The OSLD response was mapped for a wide range of average dose rates up to 9000 Gy s−1, corresponding to a ∼150 kGy s−1 instantaneous dose rate in each pulse. Two setups for ultra-high dose rate (FLASH) experiments are presented, which enable OSLDs or biological samples to be irradiated in either water-filled vials or cylinders. The OSLDs were found to be dose rate independent for all dose rates, with an average deviation <1% relative to the nominal dose for average dose rates of (1–1000) Gy s−1 when irradiated in the two setups. A third setup for irradiations in a 9000 Gy s−1 pencil beam is presented, where OSLDs are distributed in a 3 × 4 grid. Calculations of the signal averaging of the beam over the OSLDs were in agreement with the measured response at 9000 Gy s−1. Furthermore, a new method was presented to extract the beam spot size of narrow pencil beams, which is in agreement within a standard deviation with results derived from radiochromic films. The Al2O3:C OSLDs were found applicable to support radiobiological experiments in proton beams at ultra-high dose rates.
Automatic attenuation map estimation from SPECT data only for brain perfusion scans using convolutional neural networks
Authors: Chen Yuan , Goorden Marlies C , Beekman Freek J
Published: February 2021

In clinical brain SPECT, correction for photon attenuation in the patient is essential to obtain images which provide quantitative information on the regional activity concentration per unit volume (kBq.

ml

−
1

). This correction generally requires an attenuation map (

μ

map) denoting the attenuation coefficient at each voxel which is often derived from a CT or MRI scan. However, such an additional scan is not always available and the method may suffer from registration errors. Therefore, we propose a SPECT-only-based strategy for

μ

map estimation that we apply to a stationary multi-pinhole clinical SPECT system (G-SPECT-I) for 99mTc-HMPAO brain perfusion imaging. The method is based on the use of a convolutional neural network (CNN) and was validated with Monte Carlo simulated scans. Data acquired in list mode was used to employ the energy information of both primary and scattered photons to obtain information about the tissue attenuation as much as possible. Multiple SPECT reconstructions were performed from different energy windows over a large energy range. Locally extracted 4D SPECT patches (three spatial plus one energy dimension) were used as input for the CNN which was trained to predict the attenuation coefficient of the corresponding central voxel of the patch. Results show that Attenuation Correction using the Ground Truth

μ

maps (GT-AC) or using the CNN estimated

μ

maps (CNN-AC) achieve comparable accuracy. This was confirmed by a visual assessment as well as a quantitative comparison; the mean deviation from the GT-AC when using the CNN-AC is within 1.8% for the standardized uptake values in all brain regions. Therefore, our results indicate that a CNN-based method can be an automatic and accurate tool for SPECT attenuation correction that is independent of attenuation data from other imaging modalities or human interpretations about head contours.