bluuebunny/crossref_metadata_2025 huggingface dataset:
Pyridoxal kinase inhibition by artemisinins down-regulates inhibitory neurotransmission
Authors: Kasaragod Vikram Babu , Pacios-Michelena Anabel , Schaefer Natascha , Zheng Fang , Bader Nicole , Alzheimer Christian , Villmann Carmen , Schindelin Hermann
Published: December 2020

Significance

Information processing in the central nervous system relies on chemical synapses where neurotransmitters such as the inhibitory neurotransmitter γ-aminobutyric acid (GABA) are released at presynaptic nerve endings. GABA is synthesized by glutamic acid decarboxylase (GAD), an enzyme requiring pyridoxal 5'-phosphate (PLP or vitamin B6) as cofactor, the latter being synthesized by pyridoxal kinase (PDXK). Here, we show that the antimalarial drug artemisinin inhibits PDXK and describe the structural basis of this inhibition. The decrease in PLP production reduces the amount of GABA being produced, which, in turn, impacts the efficacy of GABAergic transmission. This study combined with our previous data sheds light on how artemisinins can influence inhibitory synaptic transmissions both presynaptically, as described here, and postsynaptically.
Low potential for evolutionary rescue from climate change in a tropical fish
Authors: Morgan Rachael , Finnøen Mette H. , Jensen Henrik , Pélabon Christophe , Jutfelt Fredrik
Published: December 2020

Significance

There is currently great concern about the ability of organisms to adapt to warmer environments. During heat waves, upper thermal tolerance is often critical for survival, but it is largely unknown how rapidly tolerance can evolve, especially in vertebrates. We artificially selected on upper thermal tolerance in a tropical fish to see whether and how quickly thermal tolerance evolves, and how warm acclimation prior to a thermal challenge alters this evolutionary process. Upper thermal tolerance evolved but at a slow rate toward higher temperature. Furthermore, acclimation capacity decreased in the lines selected for higher thermal tolerance. These results suggest that tropical fishes will struggle to adapt in pace with the current climate warming.
HIV proviral DNA integration can drive T cell growth ex vivo
Authors: Yoon John K. , Holloway Joseph R. , Wells Daria W. , Kaku Machika , Jetton David , Brown Rebecca , Coffin John M.
Published: December 2020

In vivo clonal expansion of HIV-infected T cells is an important mechanism of viral persistence. In some cases, clonal expansion is driven by HIV proviral DNA integrated into one of a handful of genes. To investigate this phenomenon in vitro, we infected primary CD4+ T cells with an HIV construct expressing GFP and, after nearly 2 mo of culture and multiple rounds of activation, analyzed the resulting integration site distribution. In each of three replicates from each of two donors, we detected large clusters of integration sites with multiple breakpoints, implying clonal selection. These clusters all mapped to a narrow region within the
STAT3
gene. The presence of hybrid transcripts splicing HIV to
STAT3
sequences supports a model of LTR-driven
STAT3
overexpression as a driver of preferential growth. Thus, HIV integration patterns linked to selective T cell outgrowth can be reproduced in cell culture. The single report of an HIV provirus in a case of AIDS-associated B-cell lymphoma with an HIV provirus in the same part of
STAT3
also has implications for HIV-induced malignancy.
A modern scleractinian coral with a two-component calcite–aragonite skeleton
Authors: Stolarski Jarosław , Coronado Ismael , Murphy Jack G. , Kitahara Marcelo V. , Janiszewska Katarzyna , Mazur Maciej , Gothmann Anne M. , Bouvier Anne-Sophie , Marin-Carbonne Johanna , Taylor Michelle L. , Quattrini Andrea M. , McFadden Catherine S. , Higgins John A. , Robinson Laura F. , Meibom Anders
Published: December 2020

Significance

Until now, all of the ca. 1,800 known modern scleractinian coral species were thought to produce skeletons exclusively of aragonite. AsymbioticParaconotrochus antarcticusliving in the Southern Ocean is the first example of an extant scleractinian that forms a two-component carbonate skeleton, with an inner structure made of high-Mg calcite and an outer structure composed of aragonite. This discovery adds support to the notion that the coral skeletal formation process is strongly biologically controlled. Mitophylogenomic analysis shows thatP.antarcticusrepresents an ancient scleractinian clade, suggesting that skeletal mineralogy/polymorph of a taxon, once established, is a trait conserved throughout the evolution of that clade.
Archaeological Central American maize genomes suggest ancient gene flow from South America
Authors: Kistler Logan , Thakar Heather B. , VanDerwarker Amber M. , Domic Alejandra , Bergström Anders , George Richard J. , Harper Thomas K. , Allaby Robin G. , Hirth Kenneth , Kennett Douglas J.
Published: December 2020

Significance

Maize is a global food staple with great economic and cultural importance. Archaeogenomic studies have revealed a process of protracted maize domestication and multiple waves of human-mediated dispersal in the Americas. Maize first arrived in South America as a partial domesticate, where the domestication syndrome became independently fixed and improved varieties developed away from the influence of wild gene flow. We demonstrate that hybrids of some of these improved varieties were likely reintroduced back to Central America. We hypothesize that this backflow of South American genetic material may have contributed to the development of a more productive staple, which was related to the growth and aggregation of human populations, and the formation of more complex social and political structures regionally.
Plant stem-cell organization and differentiation at single-cell resolution
Authors: Satterlee James W. , Strable Josh , Scanlon Michael J.
Published: December 2020

Significance

Plants possess the remarkable ability to grow and produce new organs throughout their lifespan, owing to the activities of persistent populations of pluripotent stem cells within their meristematic tips. Here we isolated individual cells from the microscopic shoot apical meristem (SAM) of maize and provide single-cell transcriptomic analysis of a plant shoot meristem. This study enabled an unbiased analysis of the developmental genetic organization of the maize shoot apex and uncovered evolutionarily divergent and conserved signatures of SAM homeostasis. The fine-scale resolution of single-cell analysis was used to reconstruct the process of shoot cell differentiation, whereby stem cells acquire diverse and distinct cell fates over developmental time in wild-type and mutant maize seedlings.
3D FIB-SEM reconstruction of microtubule–organelle interaction in whole primary mouse β cells
Authors: Müller Andreas , Schmidt Deborah , Xu C. Shan , Pang Song , D’Costa Joyson Verner , Kretschmar Susanne , Münster Carla , Kurth Thomas , Jug Florian , Weigert Martin , Hess Harald F. , Solimena Michele
Published: December 2020

Microtubules play a major role in intracellular trafficking of vesicles in endocrine cells. Detailed knowledge of microtubule organization and their relation to other cell constituents is crucial for understanding cell function. However, their role in insulin transport and secretion is under debate. Here, we use FIB-SEM to image islet β cells in their entirety with unprecedented resolution. We reconstruct mitochondria, Golgi apparati, centrioles, insulin secretory granules, and microtubules of seven β cells, and generate a comprehensive spatial map of microtubule–organelle interactions. We find that microtubules form nonradial networks that are predominantly not connected to either centrioles or endomembranes. Microtubule number and length, but not microtubule polymer density, vary with glucose stimulation. Furthermore, insulin secretory granules are enriched near the plasma membrane, where they associate with microtubules. In summary, we provide the first 3D reconstructions of complete microtubule networks in primary mammalian cells together with evidence regarding their importance for insulin secretory granule positioning and thus their supportive role in insulin secretion.
A method for imaging single molecules at the plasma membrane of live cells within tissue slices
Authors: Mashanov Gregory I. , Nenasheva Tatiana A. , Mashanova Tatiana , Maclachlan Catherine , Birdsall Nigel J.M. , Molloy Justin E.
Published: December 2020

Recent advances in light microscopy allow individual biological macromolecules to be visualized in the plasma membrane and cytosol of live cells with nanometer precision and ∼10-ms time resolution. This allows new discoveries to be made because the location and kinetics of molecular interactions can be directly observed in situ without the inherent averaging of bulk measurements. To date, the majority of single-molecule imaging studies have been performed in either unicellular organisms or cultured, and often chemically fixed, mammalian cell lines. However, primary cell cultures and cell lines derived from multi-cellular organisms might exhibit different properties from cells in their native tissue environment, in particular regarding the structure and organization of the plasma membrane. Here, we describe a simple approach to image, localize, and track single fluorescently tagged membrane proteins in freshly prepared live tissue slices and demonstrate how this method can give information about the movement and localization of a G protein–coupled receptor in cardiac tissue slices. In principle, this experimental approach can be used to image the dynamics of single molecules at the plasma membrane of many different soft tissue samples and may be combined with other experimental techniques.
Vassend on Verisimilitude and Counterfactual Probabilities
Authors: Niiniluoto Ilkka
Published: December 2020

Olav Benjamin Vassend proposes two solutions to the “interpretive problem” of assigning nonzero probabilities to hypotheses that are known to be false. He argues that the verisimilitude interpretation (probability expresses the degree of belief that the hypothesis is closest to the truth) and the counterfactual interpretation (probability is conditional on a false supposition) are equivalent. While Vassend’s intuition about these two solutions is basically correct, the technical details of his treatment need elaboration and correction. Appropriate tools for combining verisimilitude and Bayesian probabilities can be found in my Truthlikeness.
Exchange bias in BiFeO3 and Bi0.9La0.1FeO3 nanoparticles
Authors: Vivek S , Kumar Ajith S , Chitra Lekha C S , Nair Swapna S
Published: December 2020

The exchange bias (EB) effects of BiFeO3 (BFO) and Bi0.9La0.1FeO3 nanopowders are investigated. An EB field of 152 Oe and 902 Oe at 60 K are observed for BFO and Bi0.9La0.1FeO3, respectively, when cooled in 20 kOe magnetic field. The enhancement of EB values in the case of Bi0.9La0.1FeO3 is explained based on the combination of Malozemoff’s and domain state models. Training effect measurements data fitted with Binek’s model suggested that the origin of EB lies in the interaction between the antiferromagnetic (AFM) core and the soft magnetic shell. Memory effect measurements, thermoremanent and isoremanent magnetization studies, and time decay of thermoremanent magnetization studies are done to understand the nature of the shell of both the samples. Time decay of thermoremanent magnetization of BFO is fitted with a stretched exponential based on Kohlrausch–Williams–Watt model, the obtained shape parameter value lies in the range of Heisenberg type spin-glasses. From thermoremanent and isoremanent magnetization plots, a 2D-diluted AFM shell is observed for Bi0.9La0.1FeO3. The field cooling and the temperature dependence of EB are investigated and the results are explained based on the available models of EB.
Super-Arrhenius diffusion in a binary colloidal mixture at low volume fraction: an effect of depletion interaction due to an asymmetric barrier
Authors: Singh Jalim , Mustakim Mahammad , Anil Kumar A V
Published: December 2020

We report results from the molecular dynamics simulations of a binary colloidal mixture subjected to an external potential barrier along one of the spatial directions at low volume fraction, ϕ = 0.2. The variations in the asymmetry of the external potential barrier do not change the dynamics of the smaller particles, showing Arrhenius diffusion. However, the dynamics of the larger particles shows a crossover from sub-Arrhenius to super-Arrhenius diffusion with the asymmetry in the external potential at the low temperatures and low volume fraction. Super-Arrhenius diffusion is generally observed in the high density systems where the transient cages are present due to dense packing, e.g., supercooled liquids, jammed systems, diffusion through porous membranes, dynamics within the cellular environment, etc. This model can be applied to study the molecular transport across cell membranes, nano-, and micro-channels which are characterized by spatially asymmetric potentials.
Calibration method for the rotating axis in panoramic 3D shape measurement based on a turntable
Authors: Cai Xiaoqi , Zhong Kejun , Fu Yanjun , Chen Jianbin , Liu Yanzhao , Huang Chunzhi
Published: December 2020

In panoramic three-dimensional (3D) shape measurement based on a turntable, the point cloud registration accuracy is greatly affected by the calibration of the rotating axis. To improve the calibration accuracy of the rotating axis, a calibration method based on an auxiliary camera is proposed. The calibration procedure uses a checkerboard and an auxiliary camera. Firstly, the checkerboard is rotated on the turntable to determine the rotation axis, and is used to calibrate the relative orientation of the auxiliary camera and the measurement camera, so that the two cameras have the same world coordinate system. Then, the origin point of the coordinate of the rotation axis is obtained by the auxiliary camera, and the Z-axis direction is taken as the direction of the rotation axis. Finally, the 3D shape of the multi-view is measured by the fringe projection system, and the rotation registration is completed according to the rotation axis vector. The proposed method does not need to reconstruct the 3D coordinates of multiple points when the rotating axis is calibrated. The experimental results show that the proposed method effectively improves the calibration accuracy of the rotation axis vector, and reduces the complexity of the calibration process.
Characterisation of a multi-view fringe projection system based on the stereo matching of rectified phase maps
Authors: Shaheen A , Sims-Waterhouse D , Bointon P , Takushima S , Piano S , Leach R K
Published: December 2020

Multi-view fringe projection systems can be effective solutions to address the limitations imposed by the limited field of view, line-of-sight issues and occlusions when measuring the geometry of complex objects, associated with single camera–projector systems. However, characterisation of a multi-view system is challenging since it requires the cameras and projectors to be in a common global coordinate system. We present a method for characterising a multi-view fringe projection system which does not require the characterisation of the projector. The novelty of the method lies in determining the correspondences in the phase domain using the rectified unwrapped phase maps and triangulating the matched phase values to reconstruct the three-dimensional shape of the object. A benefit of the method is that it does not require registration of the point clouds acquired from multiple perspectives. The proposed method is validated by experiment and comparison with a conventional system and a contact coordinate measuring machine.
Time dependence of negative and positive photoconductivity for Si δ-doped AlGaAs/InGaAs/AlGaAs quantum well under various temperatures and various incident photon energies and intensities
Authors: Su Wilson Yeung-Sy , Wang Ching , Chen Chih-Ting , Huang Bu-Wei , Li Chun-Yi , Wu Chii-Bin , Wang Jyh-Shyang , Shen Ji-Lin , Chiu Kuan-Cheng
Published: December 2020

Si δ-doped AlGaAs/InGaAs/AlGaAs quantum well (QW) structure is commonly adopted as one of the core elements in modern electric and optoelectronic devices. Here, the time dependent photoconductivity spectra along the active InGaAs QW channel in a dual and symmetric Si δ-doped AlGaAs/InGaAs/AlGaAs QW structure are systematically studied under various temperatures (T = 80–300 K) and various incident photon energies (E

in
= 1.10–1.88 eV) and intensities. In addition to positive photoconductivity, negative photoconductivity (NPC) was observed and attributed to two origins. For T = 180–240 K with E

in
= 1.51–1.61 eV, the trapping of the photo-excited electrons by the interface states located inside the conduction band of InGaAs QW layer is one of the origins for NPC curves. For T = 80–120 K with E

in
= 1.10–1.63 eV, the photoexcitation of the excess ‘supersaturated’ electrons within the active InGaAs QW caused by the short cooling process is another origin.
Strain-inducing photochemical chlorination of graphene nanoribbons on SiC (0001)
Authors: Copetti Gabriela , Nunes Eduardo H , Feijó Taís O , Galves Lauren A , Heilmann Martin , Soares Gabriel V , Lopes J Marcelo J , Radtke Cláudio
Published: December 2020

As different low-dimensional materials are sought to be incorporated into microelectronic devices, graphene integration is dependent on the development of band gap opening strategies. Amidst the different methods currently investigated, application of strain and use of electronic quantum confinement have shown promising results. In the present work, epitaxial graphene nanoribbons (GNR), formed by surface graphitization of SiC (0001) on crystalline step edges, were submitted to photochemical chlorination. The incorporation of Cl into the buffer layer underlying graphene increased the compressive uniaxial strain in the ribbons. Such method is a promising tool for tuning the band gap of GNRs.
TALIF measurements of hydrogen and deuterium surface loss probabilities on quartz in low pressure high density plasmas
Authors: Yang X , Kogut D , Couëdel L , Angot T , Roubin P , Faure J-B , Cartry G
Published: December 2020

This article deals with surface loss on quartz of atomic hydrogen (H) and its isotope deuterium (D) in a low-pressure (10 Pa) pulsed inductively coupled plasma. The atomic temporal decay in the post discharge is measured by two-photon absorption laser-induced fluorescence (TALIF). From the loss rate, the atomic surface loss probability is determined. In pure hydrogen or pure deuterium gas, no isotopic effect on surface kinetics has been observed and the surface loss probabilities of H and D were found to be almost identical and equal to ∼1.8%. However, despite the lack of difference in surface loss probability, a net isotopic effect on surface loss rate due to the mass difference between the isotopes is measured. Hydrogen atoms diffuse faster and have higher flux to the plasma chamber walls than deuterium atoms. Hydrogen atoms are therefore lost at higher rate than deuterium atoms. Based on the observed isotopic difference and on the comparison between H and D TALIF signals, the isotopic effects on H and D atom production are discussed.
Effects of sequential annealing in low oxygen partial-pressure and NO on 4H-SiC MOS devices
Authors: Luo Zhipeng , Wan Caiping , Jin Zhi , Xu Hengyu
Published: December 2020

The effects of low oxygen partial pressure (low-pO2) annealing and NO annealing on both performance and reliability of silicon carbide (SiC) MOS capacitors are verified, and the sequential annealing in low-pO2 and NO is also investigated. The sequential annealing is effective to improve the reliability of SiC MOS capacitors but shows slight deterioration of interface property. The results show that annealing in the atmosphere of low partial pressure oxygen changes the distribution of defect about the SiO2/SiC interface, and influences the following NO annealing effect. The mechanism of oxidation and annealing is discussed, and some suggestions on annealing are given. This experiment provides some inspiration for the combination of annealing processes and the optimization of annealing conditions.
Optimal tuning of SMA inerter for simultaneous wind induced vibration control of high-rise building and energy harvesting
Authors: Das Sourav , Chakraborty Arunasis , Barua Ipshita
Published: December 2020

This study proposes shape memory alloy based inerter combined with electromagnetic transducer for both vibration control of buildings and energy harvesting. The proposed device has non-linear spring made of shape memory alloy for its excellent load-deformation characteristics. The hysteretic behavior of this smart material is capable of dissipating significant amount of energy. The conventional viscous damping is also replaced by a motor, which offers flexibility in damping while converting the mechanical energy into power. The optimal performance of this device demands precise tuning of its parameters for vibration control of the building, which is exposed to random wind load. This, in turn, advocates for the solution of stochastic non-linear optimization problem, which is the main aim of this study. It is proposed in two steps i.e. adopt equivalent linearization for efficient input–output characterization followed by an ensemble surrogate analysis for stochastic response quantification. A seventy six storied benchmark building is used for numerical demonstration, which clearly establishes the superiority of the passive device for simultaneous vibration control and energy harvesting over the possible range of wind speeds. The results show that the ensemble surrogate model is very efficient to predict the responses compared to a single surrogate model. Overall the performance of the controller is impressive and can be adopted for further experimental investigation prior to its use in prototype buildings.
Effects of installation position of fin-shaped rods on wind-induced vibration and energy harvesting of aeroelastic energy converter
Authors: Ding Lin , Mao Xiangxi , Yang Lin , Yan Bowen , Wang Junlei , Zhang Li
Published: December 2020

The influence of fin-shaped rod (FSR) with different installation positions on wind-induced vibration and energy harvesting of a cylinder-based aeroelastic energy harvester are studied by experiments and simulations. Two FSRs are installed symmetrically on the surface of a circular cylinder, and the coverage angle of each FSR is 20°. The installation position of FSRs on the cylinder is represented by the placement angle, θ, which varies in the range of ±160°. And the tested wind speed range is 0–6.8 m s−1. The results show that FSRs change the position of the separation point of the boundary shear layers, further affect the formation and shedding of vortices. Then the force on the cylinder changes, which causes the energy harvester to produce different vibration responses and energy outputs. When 0° < θ < 70°, back-to-back vortex-induced vibration (VIV) and galloping can be observed for FSR-cylinder, and the output power increases with the increase of wind speed, the maximum output voltage and power reach 18.1 V and 1.645 mW. For 70° ⩽ θ < 120°, the vibration of FSR-cylinder is suppressed, which is not conducive for energy harvesting. When 120° < θ ⩽ 160°, the vibration of FSR-cylinder firstly experiences VIV and then galloping occurs after reaching the critical wind speed.
A new eccentric resonance matching layer with anti-reflection characteristics for underwater acoustic scattering suppression
Authors: Duan Jinxiu , Li Shande , Wu Xiaoxun , Wang Cun , Ma Yane
Published: December 2020

The narrow frequency bandwidth and the effective frequency which cannot be low enough are two major challenges in underwater acoustics. To overcome these drawbacks, a new eccentric resonance matching layer with anti-reflection characteristics is proposed for underwater acoustic scattering suppression. Homogenization method and anti-reflection theory are applied for the design of anti-reflection structure. The complete mathematical model is developed based on the finite element method (FEM). Numerical simulations are carried out by COMSOL to verify the accuracy of the mathematical model. The results show that the proposed matching layer can significantly improve the broadband absorption capacity and can effectively suppress underwater acoustic scattering, especially at relatively low frequencies. It is a breakthrough in underwater low-frequency acoustic absorption, indicating that the structure has application prospects in underwater acoustic stealth, acoustic energy dissipation and acoustic wave regulation.
Role of film thickness and disorder in tuning perpendicular magnetic anisotropy in GdTb-FeCo alloy films
Authors: Sahoo Ajit Kumar , Chelvane J Arout , Mohanty J
Published: December 2020

GdTb-FeCo based quaternary system of various thicknesses (30, 50, 75, 150, and 300 nm) is explored in pursuit of tuneable perpendicular magnetic anisotropy (PMA). Spin reorientation and strong PMA is evident at higher film thickness. A variety of microscopic domains can be referred to as disorder in domains, have been observed. Gd-like and Tb-like contributing domains are observed in various films. A critical thickness is observed at 150 nm, where most of the Tb-sublattices are dominated over the Gd-sublattices. Magnetic parameters do not follow the trend at 150 nm, which could be attributed to a lesser extent of pinning sites impeded to domain wall motions. The experimental finding is complemented with 3D micromagnetic simulations.
Solution of chemical dynamic optimization systems using novel differential gradient evolution algorithm
Authors: Tabassum Muhammad Farhan , Saeed Muhammad , Akgül Ali , Farman Muhammad , Akram Sana
Published: December 2020

Optimization for all disciplines is essential and relevant. Optimization has played a vital role in industrial reactors’ design and operation, separation processes, heat exchangers, and complete plants in Chemical Engineering. In this paper, a novel hybrid meta-heuristic optimization algorithm which is based on Differential Evolution

(
D
E
)
,

Gradient Evolution

(
G
E
)

,

and Jumping Technique (+) named Differential Gradient Evolution Plus (DGE+) is presented. The main concept of this hybrid algorithm is to enhance its exploration and exploitation ability. The proposed algorithm hybridizes the above-mentioned algorithms with the help of an improvised dynamic probability distribution, additionally provides a new shake off method to avoid premature convergence towards local minima. The performance of

D
G
E
+

is investigated in thirteen benchmark unconstraint functions, and the results are compared to the other state-of-the-art meta-heuristics. The comparison shows that the proposed algorithm can outperform the other state-of-the-art meta-heuristics in almost all benchmark functions. To evaluate the precision and robustness of the

D
G
E
+

it has also been applied to complex chemical dynamic optimization systems such as optimization of a multimodal continuous stirred tank reactor, Lee-Ramirez bioreactor, Six-plate gas absorption tower, and optimal operation of alkylation unit, the results of comparison revealed that the proposed algorithm can provide very compact, competitive and promising performance overall complex non-linear chemical design problems.
Influence of coherent adiabatic excitation on femtosecond transient signals
Authors: Conde A Peralta , Montero R , Longarte A
Published: December 2020

Femtosecond laser pulses are the tools of choice for inducing and tracking the temporal evolution of electronic excitation in molecular systems. To obtain this information, a proper theoretical modeling of the observables monitored in these experiments is essential. Herein, we present a coherent approach to simulate the time-dependent signals that result from femtosecond pump-probe experiments with ionization detection. Thus, the transient signals derived from femtosecond pump-probe experiments are analyzed in terms of the coherent evolution of the energy levels perturbed by the excitation pulse. The model system is treated as the sum of independent two-level subsystems that evolve adiabatically or are permanently excited, depending on the detuning from the central wavelength of the excitation laser. This approach will allow us to explain numerically and analytically the convergence between the coherent and incoherent (rate equations) treatments for complex multi-level systems. It will be also shown that the parameter that determines the validity of the incoherent treatment is the distribution of states outside and inside the laser bandwidth, rather than the density of states as it is commonly accepted.
Sufficient sampling for kriging prediction of cortical potential in rat, monkey, and human µECoG
Authors: Trumpis Michael , Chiang Chia-Han , Orsborn Amy L , Bent Brinnae , Li Jinghua , Rogers John A , Pesaran Bijan , Cogan Gregory , Viventi Jonathan
Published: December 2020

Objective. Large channel count surface-based electrophysiology arrays (e.g. µECoG) are high-throughput neural interfaces with good chronic stability. Electrode spacing remains ad hoc due to redundancy and nonstationarity of field dynamics. Here, we establish a criterion for electrode spacing based on the expected accuracy of predicting unsampled field potential from sampled sites. Approach. We applied spatial covariance modeling and field prediction techniques based on geospatial kriging to quantify sufficient sampling for thousands of 500 ms µECoG snapshots in human, monkey, and rat. We calculated a probably approximately correct (PAC) spacing based on kriging that would be required to predict µECoG fields at

≤

10% error for most cases (95% of observations). Main results. Kriging theory accurately explained the competing effects of electrode density and noise on predicting field potential. Across five frequency bands from 4–7 to 75–300 Hz, PAC spacing was sub-millimeter for auditory cortex in anesthetized and awake rats, and posterior superior temporal gyrus in anesthetized human. At 75–300 Hz, sub-millimeter PAC spacing was required in all species and cortical areas. Significance. PAC spacing accounted for the effect of signal-to-noise on prediction quality and was sensitive to the full distribution of non-stationary covariance states. Our results show that µECoG arrays should sample at sub-millimeter resolution for applications in diverse cortical areas and for noise resilience.
Effect of geometric and magnetic boundary conditions on magnetic islands in 3D force-free ideal MHD equilibria
Authors: Benedett T.E. , Hansen C.J.
Published: December 2020

Three-dimensional boundary features and magnetic perturbations affect the magnetic topology of the force-free ideal MHD equilibria formed within a given volume. The use of the PSI-Tet 3D finite-element equilibrium code reveals the existence of magnetic islands inside such equilibria within boundaries with three-dimensional features in configurations that directly depend on the natures of those features. The nature and limits of the influence of such features are explored, as is the influence of flux boundary conditions to qualitatively identify the structure of magnetic islands in Taylor state equilibria with three-dimensional boundary conditions.
Mesoporous silica prepared via a green route: a comparative study for the removal of crystal violet from wastewater
Authors: Naseem Taiba , Baig Mirza Mahmood , Warsi Muhammad Farooq , Hussain Rafaqat , Agboola Philips O , Waseem Muhammad
Published: December 2020

In this present study, a wet chemical method with environmentally friendly and cost-effective bagasse ash is used to prepare the mesoporous silica structures. Significant amounts of silica (SiO2) (∼75 percent) were measured in the bagasse ash as confirmed by x-ray fluorescence spectroscopy (XRF). The porous silica particles with uniform morphology showed a weight loss of ∼150 to ∼45%. The removal of crystal violet was performed with silica extracted from bagasse ash along with two other silica samples prepared from commercially available sodium silicate and TEOS for comparison purposes. The equilibrium adsorption data followed the Langmuir model for both linear and non-linear adsorption isotherm. The maximum monolayer capacity was found to be 26.53 mg/g. From the Langmuir isotherm, the value of ∆H is (SiO2 (SS) = 0.83, SiO2 (BA) = 5.19, and SiO2 (TEOS) = 3.05), which indicates that the uptake of CV dye on mesoporous silica particles could be attributed to physical adsorption. The positive value of ∆H confirms that the adsorption is endothermic, and the positive value of ∆S indicates a certain structural modification and randomness increases in solid/liquid interface. The respective activation energy values for CV dye adsorption on mesoporous SiO2 (SS), SiO2 (BA), and SiO2 (TEOS) are 0.83, 5.19, and 3.05 kJ mol−1. All values are less than 8, showing that it is corresponding to physical adsorption. The findings further show that silica obtained from the bagasse ash is a cost-effective and equally effective adsorbent for the removal of crystal violet from an aqueous solution.
Global stability of spatially nonhomogeneous steady state solution in a diffusive Holling-Tanner predator-prey model
Authors: Ni Wenjie , Shi Junping , Wang Mingxin
Published: December 2020

The global stability of the nonhomogeneous positive steady state solution to a diffusive Holling-Tanner predator-prey model in a heterogeneous environment is proved by using a newly constructed Lyapunov function and estimates of nonconstant steady state solutions. The techniques developed here can be adapted for other spatially heterogeneous consumer-resource models.
Estimates for sums of eigenvalues of the free plate with nonzero Poisson’s ratio
Authors: Li Shan , Mao Jing
Published: December 2020

By using the Fourier transform, we successfully give Kröger-type estimates for sums of eigenvalues of the free plate (under tension and with nonzero Poisson’s ratio) in terms of the dimension of the ambient space, the volume of the domain, the tension parameter and the Poisson’s ratio.
A dichotomy for subsymmetric basic sequences with applications to Garling spaces
Authors: Albiac F. , Ansorena J. , Dilworth S. , Kutzarova Denka
Published: December 2020

Our aim in this article is to contribute to the study of the structure of subsymmetric basic sequences in Banach spaces (even, more generally, in quasi-Banach spaces). For that we introduce the notion of positionings and develop new tools which lead to a dichotomy theorem that holds for general spaces with subsymmetric bases. As an illustration of how to use this dichotomy theorem we obtain the classification of all subsymmetric sequences in certain types of spaces. To be more specific, we show that Garling sequence spaces have a unique symmetric basic sequence but no symmetric basis and that these spaces have a continuum of subsymmetric basic sequences.
Leo Tolstoy and US Utopian Literature
Authors: Alekseeva Galina
Published: December 2020

American utopia in literary and documentary texts by American writers had an impact on Leo Tolstoy’s ideas and writings, which can be seen in the marginalia and annotations he left in his extensive personal library.

The concept of utopia was deeply ingrained in Tolstoy, beginning with the childish legend of “the green stick” engraved with the magic words of universal happiness. As a child Tolstoy was fascinated with the potential of the “green stick” and its secret that could make all men happy, and he tried many times to find it. Tolstoy examined and developed this concept of universal happiness throughout different periods of his life.

From the mid-1880s to his departure from Yasnaya Polyana in 1910, Tolstoy stayed in close contact with American religious writers. During this period, he received many books and periodicals from America and thus got to know the works of numerous American writers, philosophers, and public figures who were close to him in spirit. Tolstoy had a keen interest in American history, culture, art, traditions, and especially in the religious movements of America. Some of these ideas found expression in Tolstoy’s fiction and other writings.
The Economics of Hacking
Authors: Hui Kai-Lung , Zhou Jiali
Published: December 2020

Hacking is becoming more common and dangerous. The challenge of dealing with hacking often comes from the fact that much of our wisdom about conventional crime cannot be directly applied to understand hacking behavior.

Against this backdrop, hacking studies are reviewed in view of the new features of cybercrime and how these features affect the application of the classical economic theory of crime in the cyberspace. Most findings of hacking studies can be interpreted with a parsimonious demand-and-supply framework. Hackers decide whether and how much to “supply” hacking by calculating the return on hacking over other opportunities. Defenders optimally tolerate some level of hacking risks because defense is costly. This tolerance can be interpreted as an indirect “demand” for hacking. Variations in law enforcement, hacking benefits, hacking costs, legal alternatives, private defense, and the dual-use problem can variously affect the supply or demand for hacking, and in turn the equilibrium amount of hacking in the market. Overall, it is suggested that the classical economic theory of crime remains a powerful framework to explain hacking behaviors. However, the application of this theory calls for considerations of different assumptions and driving forces, such as psychological motives and economies of scale in offenses, that are often less prevalent in conventional (offline) criminal behaviors but that tend to underscore hacking in the cyberspace.
Beliefs and Stereotypes About LGBT People
Authors: Hicks Gary R.
Published: December 2020

The public’s perception of, beliefs about, and interest in LGBT individuals and the issues impacting them has long had great significance to the community’s social, political, and legal progress. The last decade has seen monumental changes in public attitudes about LGBT people and the laws that affect them in the United States and around the world. Much of this change has been positive, including the landmark Supreme Court decision to legalize same-sex marriage. In some parts of the world—even those that have witnessed great strides for LGBT equality—there have also been signs of a backlash against the community’s newfound rights and visibility in society. Stereotypes of LGBT individuals, mostly negative, have been responsible for much of this reaction, as well as their historically negative view in by the public. In the 20th and 21st centuries, the mass media has played a major role in creating and perpetuating these stereotypes.
Coming Out and Political Attitudes Among Sexual Minorities
Authors: Page Douglas
Published: December 2020

A nascent body of research is growing on the issue of disclosing one’s sexuality, also termed “coming out,” and the implications for attitudes, behavior, and health. This research engages (a) the political attitudes of those reporting their sexual identity, and (b) the social conditions that lead people to express different forms of sexual identity. Four main findings help to characterize the relationship between coming out and political attitudes among sexual minorities. First, people who come out tend to be socially liberal, but the reasons behind this pattern remain unclear. Second, tolerant social conditions correlate with coming out; expressions of tolerant attitudes; and political engagement on behalf of lesbian, gay, and bisexual rights. Third, the reverse holds as well: Intolerant, homophobic social conditions correlate with the concealment of one’s homosexuality and the expression of homophobic attitudes. Fourth, homophobic social conditions also may lead to worse mental health outcomes, which in turn reduce political efficacy and participation. However, the causal relationships between social conditions, coming out, political outcomes, and health outcomes elude existing research. Future research can unpack these relationships and include more cases outside Western Europe and North America, where most research on this topic is conducted.
Legislative and Judicial Politics of LGBT Rights in the European Union
Authors: Belavusau Uladzislau
Published: December 2020

Since the 1980s, the law of the European Union (EU) has become a substantial transnational source of political empowerment for LGBT actors in Europe. The Rome Treaty (1957), which established the European Economic Community, contained a gender equality clause. In the 1990s, this provision was used to protect employment rights of intersex individuals via litigation schemes based on EU law. Yet the subsequent attempts to push forward a similar legal protection for gay and lesbian equality at the Court of Justice of the European Union (CJEU), based on the EU sex-equality clause, failed. Since then, the position of the LGBT community in EU legislative politics has evolved significantly through two dimensions. First, the Amsterdam Treaty (1997) extended the number of grounds protected against discrimination in EU law, adding sexual orientation, among others, to this palette. The Amsterdam Treaty permitted the EU Council to adopt the Framework Equality Directive 2000/78/EC, an instrument of secondary Union law that has safeguarded minimum standards of protection against homophobia in relation to matters of employment in all member states. This framework EU legislation has been used by LGBT litigants in their fight for equal working opportunities and pension rights at the CJEU. Second, the introduction of EU citizenship by virtue of the Maastricht Treaty (1992) and the respective secondary law (the EU Citizenship Directive 2004/38/EC) have paved the way for status recognition of same-sex spouses in the member states that have not previously recognized same-sex partnership or marriage. The future of LGBT legislative politics and the LGBT community in Europe will largely depend on whether EU law is able to extend protection beyond the current confines of the employment area, broaden its scope to cover social dimensions such as health and education, and fully recognize same-sex marriages and partnerships throughout the EU.
Eritrea: The Everyday Politics of Mass Militarization
Authors: Riggan Jennifer
Published: December 2020

Eritrea has a long history as a heavily militarized nation, dating back to its 30-year war for independence from Ethiopia. Militarization is a core component of Eritrean nationalism and state formation, which is arguably forged out of war but is also implicated in Eritrea’s problematic human rights record. Following Eritrea’s 1991 independence, the country was poised to democratize and liberalize. At that time, the country also began an intensive process of nation-building of which militarization was a central part. In 1995, Eritrea introduced the national service program. Eritrea’s national/military service, which requires 6 months of military training and 12 months of free military or civil service for all Eritreans (male and female), initially enjoyed widespread public support although there were always concerns about harsh living and labor conditions. In 1998, a border war with Ethiopia broke out. At this time, those who had military training in national service were recalled. Although fighting ended in 2000, the border war deepened Eritrea’s adherence to militarization as a key strategy of national defense, nation-building, and development. A condition of no-peace, no-war followed the border war. The long period of no-war, no-peace with Ethiopia allowed Eritrea’s president, Isaias Afewerki, to consolidate his power, deepen authoritarian rule, and extend the national service program indefinitely. The indefinite extension of national service meant that conscripts were not demobilized and new recruits into national service could not be assured that they would ever be released. Due to the indefinite extension of military service, harsh conditions in the military, and extreme punishments for those who try to escape the military, Eritrea’s national/military service requirement is at the center of concern about human rights and civil liberties in Eritrea. Militarization has since become fused with state control and punishment, leading to human rights and civil liberties violations and the mass flight of close to half a million Eritreans over the past decades. Despite the announcement in summer of 2018 that Eritrea and Ethiopia had finally agreed to peace, no one has been released from the military and Eritreans continue to flood out of the country to avoid national service conditions which have been equated with slavery.
History of Social Psychology at Mid-20th Century
Authors: Pettigrew Thomas F.
Published: December 2020

The discipline of psychology has an extremely broad range—from the life sciences to the social sciences, from neuroscience to social psychology. These distinctly different components have varying histories of their own. Social psychology is psychology’s social science wing. The major social sciences—anthropology, economics, sociology, and political science—all had their origins in the 19th century or even earlier. But social psychology is much younger; it developed both in Europe and North America in the 20th century.

The field’s enormous growth over the past century began modestly with a few scant locations, several textbooks, and a single journal in the 1920s. Today’s social psychologists would barely recognize their discipline in the years prior to World War II. But trends forming in the 1920s and 1930s would become important years later.

With steady growth, especially starting in the 1960s, the discipline gained thousands of new doctorates and multiple journals scattered throughout the world. Social psychology has become a recognized, influential, and often-cited social science. It is the basis, for example, of behavioral economics as well as such key theories as authoritarianism in political science. Central to this extraordinary expansion were the principal events of mid-20th century. World War II, the growth of universities and the social sciences in general, rising prosperity, statistical advances, and other global changes set the stage for the discipline’s rapid development.

Together with this growth, social psychology has expanded its topics in both the affective and cognitive domains. Indeed, new theories are so numerous that theoretical integration has become a prime need for the discipline.