bluuebunny/crossref_metadata_2025 huggingface dataset:
Leapfrogging criteria for a line vortex pair external to a circular cylinder
Authors: Turner M. R.
Published: September 2020

The interaction of two line vortices of differing strengths in the presence of a circular cylinder is considered. Explicit criteria are derived, a function of vortex strengths (including strengths of opposite signs) and the cylinder radius, which separate different behaviors of the system. If the initial position of the vortices satisfies these criteria, they will undergo a periodic leapfrogging motion as they rotate around the cylinder; otherwise, the vortices still interact weakly with one another except without leapfrogging. This is in contrast to the planar wall case where if no periodic leapfrogging occurs, the vortices move apart and do not interact with each other. Numerical results for initial vortex positions which do and do not satisfy these criteria are presented to demonstrate the different motions available, as well as the robustness of the criteria.
Particle physicists hash out long-term strategy for Europe
Authors: Feder Toni
Published: September 2020

Among the goals are to pick a Higgs factory, carry out R&D on accelerators and detectors, conduct feasibility studies, and improve environmental sustainability.
Human social preferences cluster and spread in the field
Authors: Ehlert Alexander , Kindschi Martin , Algesheimer René , Rauhut Heiko
Published: September 2020

Significance

How does society maintain the high levels of prosociality in humans, which are so puzzling to explain? Previous laboratory evidence suggests that human social networks play a critical role; however, if and how this role is played out in field settings is not well understood. We demonstrate that intrinsic social preferences, such as fairness and altruism, cluster and spread in human real-world friendship networks. More importantly, however, our findings show that individuals do not choose friends based on cooperativeness—friendship networks influence whether individuals become cooperative or selfish. We conclude that social learning contributes substantially to the ontogeny of prosociality, signifying the role of culture for the development and maintenance of large-scale human cooperation.
The emergence of a functionally flexible brain during early infancy
Authors: Yin Weiyan , Li Tengfei , Hung Sheng-Che , Zhang Han , Wang Li , Shen Dinggang , Zhu Hongtu , Mucha Peter J. , Cohen Jessica R. , Lin Weili
Published: September 2020

Significance

While adult brains are known to be functionally flexible, the emergence of a functionally flexible brain during early infancy is largely uncharted due the lack of approaches to assess neural flexibility in infants. Using recent advances of multilayer network approaches and a cohort of typically developing children who underwent longitudinal MRI during the first 2 y of life, we investigated the developmental characteristics of brain neural flexibility. The temporal and spatial emergence of a functionally flexible brain was revealed. Brain regions with high neural flexibility appear consistent with the core regions supporting cognitive flexibility processing in adults, whereas brain regions governing basic brain functions exhibit lower neural flexibility, demonstrating the emergence of functionally flexible brain during early infancy.
CRL5-dependent regulation of the small GTPases ARL4C and ARF6 controls hippocampal morphogenesis
Authors: Han Jisoo S. , Hino Keiko , Li Wenzhe , Reyes Raenier V. , Canales Cesar P. , Miltner Adam M. , Haddadi Yasmin , Sun Junqing , Chen Chao-Yin , La Torre Anna , Simó Sergi
Published: September 2020

Significance

In comparison to the neocortex, the molecular mechanisms that contribute to neuron migration, particularly pyramidal neuron migration, and localization in the hippocampus remain for the most part unknown. The present study characterizes the role of the E3 ubiquitin ligase CRL5 during hippocampal pyramidal neuron migration. CRL5 down-regulates the small GTPase ARL4C and its associated signaling effectors, in a posttranscriptional fashion, to localize pyramidal neurons in the hippocampus. CRL5-dependent regulation of ARL4C signaling is also required for the formation of a single, apically oriented dendrite in pyramidal neurons and for its full outgrowth to the superficial strata of the hippocampus. Therefore, this study uncovers CRL5 and ARL4C signaling as crucial molecular determinants for hippocampal morphogenesis.
Stochastic reaction networks in dynamic compartment populations
Authors: Duso Lorenzo , Zechner Christoph
Published: September 2020

Significance

Many biochemical processes in living systems take place in compartmentalized environments, where individual compartments can interact with each other and undergo dynamic remodeling. Studying such processes through mathematical models poses formidable challenges because the underlying dynamics involve a large number of states, which evolve stochastically with time. Here we propose a mathematical framework to study stochastic biochemical networks in compartmentalized environments. We develop a generic population model, which tracks individual compartments and their molecular composition. We then show how the time evolution of this system can be studied effectively through a small number of differential equations, which track the statistics of the population. Our approach is versatile and renders an important class of biological systems computationally accessible.
Restoration of fragmentary Babylonian texts using recurrent neural networks
Authors: Fetaya Ethan , Lifshitz Yonatan , Aaron Elad , Gordin Shai
Published: September 2020

Significance

The documentary sources for the political, economic, and social history of ancient Mesopotamia constitute hundreds of thousands of clay tablets inscribed in the cuneiform script. Most tablets are damaged, leaving gaps in the texts written on them, and the missing portions must be restored by experts. This paper uses available digitized texts for training advanced machine-learning algorithms to restore daily economic and administrative documents from the Persian empire (sixth to fourth centuries BCE). As the amount of digitized texts grows, the model can be trained to restore damaged texts belonging to other genres, such as scientific or literary texts. Therefore, this is a first step for a large-scale reconstruction of a lost ancient heritage.
People with disagreeable personalities (selfish, combative, and manipulative) do not have an advantage in pursuing power at work
Authors: Anderson Cameron , Sharps Daron L. , Soto Christopher J. , John Oliver P.
Published: September 2020

Significance

Are disagreeable individuals more likely to attain power than agreeable individuals? This question is important because highly disagreeable individuals in positions of power can do a lot of damage. For example, CEOs who are nasty and bullying create cultures of abuse and tend to lead their organizations to fail. In two longitudinal prospective studies, we found that disagreeableness did not predict the attainment of power. Selfish, deceitful, and aggressive individuals were no more likely to attain power than were generous, trustworthy, and nice individuals. Why not? Disagreeable individuals were intimidating, which would have elevated their power, but they also had poorer interpersonal relationships at work, which offset any possible power advantage their behavior might have provided.
Helper bacteria halt and disarm mushroom pathogens by linearizing structurally diverse cyclolipopeptides
Authors: Hermenau Ron , Kugel Susann , Komor Anna J. , Hertweck Christian
Published: September 2020

Significance

P. tolaasii
is the causative agent of brown blotch disease in the common button mushroom
Agaricus bisporus
and responsible for tremendous losses in mushroom farms every year. The pathogen relies on two different cyclic lipopeptides during infection: the pore forming toxin tolaasin and the motility conferring biosurfactant pseudodesmin. In this study, we show how enzymes produced by helper bacteria of the genus
Mycetocola
provide protection to the mushroom via lipopeptide cleavage. Using bioactivity guided fractionation of the proteome, we could identify the key enzyme in toxin inactivation. Deciphering such protective interactions paves the way for the development of biocontrol agents for use in both agriculture and medicine.
Relationship of estrogen synthesis capacity in the brain with obesity and self-control in men and women
Authors: Biegon Anat , Alia-Klein Nelly , Alexoff David L. , Fowler Joanna S. , Kim Sung Won , Logan Jean , Pareto Deborah , Preston-Campbell Rebecca , Wang Gene-Jack , Hildebrandt Tom
Published: September 2020

Significance

Obesity is a major public health problem in a growing proportion of children and adults in the developed world. Estrogen influences body weight and behavioral responses to appetitive stimuli. Estrogen biosynthesis is catalyzed by the enzyme aromatase in all organs measured, including the brain. Using the aromatase radiotracer [
11
C]vorozole, we measured aromatase availability in the amygdala in healthy-weight to obese adults. Obesity was associated with lower aromatase availability and less constraint independent of sex and age. Variability in brain estrogen synthesis may contribute to obesity by directly regulating feeding and broadly by affecting self-control. These findings suggest that brain aromatase imaging offers a method for characterizing the role of brain estrogen in obesity and other impairments in self-regulation.
Protecting memory from misinformation: Warnings modulate cortical reinstatement during memory retrieval
Authors: Karanian Jessica M. , Rabb Nathaniel , Wulff Alia N. , Torrance McKinzey G. , Thomas Ayanna K. , Race Elizabeth
Published: September 2020

Significance

Exposure to misleading information can distort memory for past events (misinformation effect). Here, we show that providing individuals with a simple warning about the threat of misinformation significantly reduces the misinformation effect, regardless of whether warnings are provided proactively (before exposure to misinformation) or retroactively (after exposure to misinformation). In the brain, this protective effect of warning is associated with increased reactivation of sensory regions associated with the original event and decreased reactivation of sensory regions associated with the misleading information. These findings reveal that warnings can protect memory from misinformation by modulating reconstructive processes at the time of memory retrieval and have important practical implications for improving the accuracy of eyewitness testimony as well as everyday memory reports.
Fine-scale heterogeneity in
Schistosoma mansoni
force of infection measured through antibody response
Authors: Arnold Benjamin F. , Kanyi Henry , Njenga Sammy M. , Rawago Fredrick O. , Priest Jeffrey W. , Secor W. Evan , Lammie Patrick J. , Won Kimberly Y. , Odiere Maurice R.
Published: September 2020

Significance

Schistosomiasis is one of the most common parasitic diseases in the world, and most infected people (90%) live in Africa. Global control efforts use measures of population-level transmission to target programs and assess progress toward elimination. Monitoring
Schistosoma mansoni
transmission has traditionally relied on examining stool with microscopy, which is difficult to scale in large programs and has low sensitivity as infection burdens decline. Our results show that antibody-based measures of transmission align well with stool-based measures, provide higher sensitivity at lower levels of transmission, and enable fine-scale estimates of force of infection by geography and age. The findings represent a major step toward use of serosurveillance to guide schistosomiasis control efforts in Africa.
Cuscuta australis
(dodder) parasite eavesdrops on the host plants’ FT signals to flower
Authors: Shen Guojing , Liu Nian , Zhang Jingxiong , Xu Yuxing , Baldwin Ian T. , Wu Jianqiang
Published: September 2020

Significance

In many plants, flowering is regulated by environmental cues, such as day length. Under flowering-inductive conditions, leaves synthesize and transmit FLOWERING LOCUS T (FT) protein to the shoot apex, where FT activates flowering. Dodder
Cuscuta australis
, which is a root- and leafless parasitic plant, however, very likely does not have fully functional
FT
genes, and it flowers only when the host plants flower. We show that host-synthesized FT protein is able to move into dodder stems, where FT physically interacts with dodder FD transcription factor, activating flowering of dodder. This specific manner of flowering allows dodder to synchronize its flowering time with that of the host plant, and this is likely a trait that is beneficial for dodder’s reproductive success.
Specialized translators in the GDR
Authors: Blum Hanna , Hofeneder Philipp
Published: September 2020

This article aims to show that not only was translation in the cultural Cold War used to manipulate ideologies across the Iron Curtain, but it also played a decisive role in establishing socialist structures in satellite states, including those involved with the transfer of knowledge, thus giving a louder voice to translators as vital and yet underrepresented agents. Specifically, we examine the translators of the journal Sowjetwissenschaft (published in the GDR) to shed light on the identities of the translators and their role in the transfer of knowledge within the Socialist bloc. Individual scientific translators are investigated in greater detail to reveal their importance in establishing and preserving socialist structures and discourses during the cultural Cold War.
Phase transformation study during diffusion brazing of γ-TiAl intermetallic using amorphous Ni-based filler metals
Authors: Kokabi Dariush , Kaflou Ali
Published: September 2020

The paper aims at understanding the microstructure evolution of the diffusion brazing of γ-TiAl intermetallic compound using two Ni-based filler metals, a ternary Ni-Si-B, and a quinary Ni-Cr-Fe-Si-B. It was found that the joint region comprised of two distinct zones: analogous reaction layers adjacent to the TiAl substrates and a solidified zone at the middle of the joint region. The reaction layers consisted of separate intermetallic phases regions including ternary and binary Ti-Ni-Al intermetallic compounds. The solidified zone mainly composed of the Al1-xNi3Six isostructural solid solution and athermally Ni-boride or Ni-Cr rich borides containing eutectic microstructures at the joint centerline. The maximum shear strength was 240 MPa, and obtained by using Ni-Cr-Fe-Si-B filler metal. Fracture of the joint with Ni-Cr-Fe-Si-B filler occurred in the reaction layer/solidified zone interface, but joint with Ni-Si-B filler was fractured at solidified zone.

GRAPHICAL ABSTRACT
Project CHOICE: Choosing Healthy Options in Coping with Emotions, an EMA/EMI Plus In-Person Intervention for Alcohol Use
Authors: Blevins Claire E. , Marsh Eliza L. , Stein Michael D. , Schatten Heather T. , Abrantes Ana M.
Published: September 2020

Background

Emerging adulthood (18–25 years) represents a risky time for mental health and substance use. Emerging adults are particularly susceptible to problematic patterns of substance use, especially if they experience anxiety and/or depression and use substances as a way to cope with such issues. However, many mental health treatments do not address substance use. We developed an ecological momentary assessment and intervention (EMA/EMI) to specifically target the motive of drinking to cope with anxiety/depression.

Methods

Project CHOICE was a 6-week intervention that paired in-person normative feedback with daily EMA and, if an individual reported negative affect and intent to drink, an EMI was immediately sent to their phone (a personally-chosen coping skill). We recruited n = 20 (55% female, mean age 21.74, 85% Caucasian and 75% non-Hispanic/Latino) individuals from a psychiatric partial hospitalization program for a 6-week open trial of the CHOICE intervention and re-assessed at the 6-week follow-up point.

Results

Results indicated that drinking variables and coping motives were highly correlated at baseline. Days of drinking, alcohol-related problems, and coping motives significantly decreased over time following the intervention. Results indicated high levels of feasibility and acceptability.

Conclusions

This open pilot represents a feasible, acceptable, and promising direction in delivering interventions in the moment when risk is highest, utilizing smartphone capabilities.
Impact of Extended Release Naltrexone on Health-Related Quality of Life in Individuals with Legal Involvement and Opioid use Disorders
Authors: Pivovarova Ekaterina , Min Hye Sung , Friedmann Peter D.
Published: September 2020

Background

Understanding the impact of medications for opioid use disorder on health related quality of life (QOL) may help to explain why few individuals with legal involvement remain in treatment, specifically those receiving opioid antagonists. QOL is an established predictor of treatment retention and has been shown to improve with some treatment for opioid use disorder. Yet limited research has examined QOL with opioid antagonists. We examined the impact of extended release naltrexone (XR-NTX) on QOL and retention in treatment in a randomized, multi-site trial of individuals with legal involvement.

Methods

The participants were 308 community-dwelling adults with current or recent legal involvement with opioid dependence at five site across United States. They were randomized to receive XR-NTX or treatment as usual for 6 months. QOL was measured every 2 weeks using Euro QOL individual items, summary index score, and health state today metric.

Results

No significant difference in QOL scores were observed between the two groups at the completion of active treatment or on follow up at 52 and 78 weeks. There were no time effects of treatment on scores. Contrary to expectation, baseline and average QOL did not predict retention in treatment.

Conclusion

In contrast to prior research, our findings did not demonstrate significant changes (improvements or decreases) in QOL associated with XR-NTX treatment. Clinicians may consider that individuals receiving XR-NTX may not experience changes in perceived well-being in response to treatment and consider discussing with patients that they may not necessarily perceive improvement in their QOL. This may help to ground patient's expectations about the effects of treatment and potentially reduce attrition from treatment with opioid antagonists.
Loss of CBX2 induces genome instability and senescence-associated chromosomal rearrangements
Authors: Baumann Claudia , Zhang Xiangyu , De La Fuente Rabindranath
Published: September 2020

The polycomb group protein CBX2 is an important epigenetic reader involved in cell proliferation and differentiation. While CBX2 overexpression occurs in a wide range of human tumors, targeted deletion results in homeotic transformation, proliferative defects, and premature senescence. However, its cellular function(s) and whether it plays a role in maintenance of genome stability remain to be determined. Here, we demonstrate that loss of CBX2 in mouse fibroblasts induces abnormal large-scale chromatin structure and chromosome instability. Integrative transcriptome analysis and ATAC-seq revealed a significant dysregulation of transcripts involved in DNA repair, chromocenter formation, and tumorigenesis in addition to changes in chromatin accessibility of genes involved in lateral sclerosis, basal transcription factors, and folate metabolism. Notably, Cbx2−/− cells exhibit prominent decondensation of satellite DNA sequences at metaphase and increased sister chromatid recombination events leading to rampant chromosome instability. The presence of extensive centromere and telomere defects suggests a prominent role for CBX2 in heterochromatin homeostasis and the regulation of nuclear architecture.
Brain transforms natural killer cells that exacerbate brain edema after intracerebral hemorrhage
Authors: Li Zhiguo , Li Minshu , Shi Samuel X. , Yao Nan , Cheng Xiaojing , Guo Ai , Zhu Zilong , Zhang Xiaoan , Liu Qiang
Published: September 2020

Perihematomal edema (PHE) occurs within hours after intracerebral hemorrhage (ICH), leading to secondary injury manifested by impaired blood–brain barrier (BBB) integrity and destruction of adjacent tissue. To dissect the mechanisms underlying PHE formation, we profiled human and mouse perihematomal tissues and identified natural killer (NK) cells as the predominant immune cell subset that outnumbers other infiltrating immune cell types during early stages of ICH. Unbiased clustering of single-cell transcriptional profiles revealed two major NK cell subsets that respectively possess high cytotoxicity or robust chemokine production features in the brain after ICH, distinguishing them from NK cells of the periphery. NK cells exacerbate BBB disruption and brain edema after ICH via cytotoxicity toward cerebral endothelial cells and recruitment of neutrophils that augment focal inflammation. Thus, brain-bound NK cells acquire new features that contribute to PHE formation and neurological deterioration following ICH.
Event-by-event mean-p
t fluctuations from the AMPT model with a dynamical quark coalescence mechanism
Authors: Xu Zhenyu , Liu Jianli , Wei Donghai , Huo Jiahong , Zhang Chunhui , Huo Lei
Published: September 2020

The event-by-event fluctuations of the mean transverse momentum (p
t) in Au + Au collisions at

s

NN

=
7.7

–200 GeV and Pb + Pb collisions at

s

NN

=
2.76

T
e
V

are analyzed using a multiphase transport model (AMPT) with a dynamical quark coalescence mechanism (DQCM). The analysis shows that at 19.6 GeV there exists a splitting between the relative dynamical mean-p
t fluctuation from the DQCM AMPT and from the original AMPT (i.e., AMPT with string melting) at freeze-out. Based on the hadron information obtained at different stages of nuclear collisions from the AMPT model, we show that this splitting first arises from the quark coalescence hadronization process, and then develops during the resonance decay process. The results are compared with measurements from STAR at the relativistic heavy-ion collider (RHIC) and ALICE at the large hadron collider (LHC). The comparison shows that the relative dynamical mean-p
t fluctuation for non-peripheral collisions at 200 GeV and 2.76 TeV can be explained by these two coalescence scenarios. After introducing the DQCM into the AMPT model, the results become slightly larger and appeared to be closer to the experimental data for

s

NN

=
7.7

–62.4  GeV. Specially, the relative dynamical mean-p
t fluctuation with centrality of 0%–5% can be well reproduced by the DQCM AMPT.
Vision-based correspondence using relaxation algorithms for particle tracking velocimetry
Authors: Benkovic Théo , Krawczynski Jean-François , Druault Philippe
Published: September 2020

A new particle tracking algorithm is derived based on consolidated methods, with the aim of overcoming the current limits encountered with high particle density flows. The proposed method consists of an integration of the relaxation algorithm based on matching probabilities into vision-based features association concepts. Hybridization with PIV pre-analysis is suggested to help with the estimation of parameters. A dual calculation strategy is also developed in order to reduce the amount of spurious vectors. Simulation tests using synthetically generated images are carried out to evaluate the sensitivity of the proposed method to the particle image density, the background noise and the nature of the flow. Three flow configurations with a growing degree of complexity are successively considered: a 2D flow over a moving wall, a steady 2D Lamb–Oseen vortex ring, and a 3D unsteady homogeneous isotropic turbulence. The ability of the new tracking algorithm to provide better matching performances with high reliability than conventional techniques, out of a dense particle image field, is demonstrated.
A device for the local measurement of water evaporation rate
Authors: Hall Christopher , Hamilton Andrea
Published: September 2020

Evaporation plays a central but largely invisible role in the moisture dynamics of buildings and urban microenvironments. Local evaporation rates control water flux and material damage, and are altered by climate change. While potential evaporation (PE) (or potential evapotranspiration (PET)) can be estimated on the large-scale, there are few if any methods of making local PE measurements. We describe here a simple device (patch evaporimeter) for measuring PE at point locations on the surfaces of built structures. The device combines a sintered-quartz disc as a water reservoir and a low-cost remotely-readable humidity sensor to detect the drying time. The patch evaporimeter may be widely useful in monitoring evaporation rates in a variety of microenvironments.
Thermal conductivity of free-standing silicon nanowire using Raman spectroscopy
Authors: Sahoo Sandhyarani , Mallik Sameer Kumar , Sahu Mousam Charan , Joseph Anjana , Singh Satyabrata , Gupta Sanjeev K , Rout Bibhudutta , Pradhan Gopal K , Sahoo Satyaprakash
Published: September 2020

Low dimensional systems, nanowires (NWs), in particular, have exhibited excellent optical and electronic properties. Understanding the thermal properties in semiconductor NWs is very important for their applications in electronic devices. In the present study, the thermal conductivity of a freestanding silicon NW is estimated by employing Raman spectroscopy. The advantage of this technique is that the excitation source (laser) acts as both the heater and probe. The variations of the first-order Raman peak position of the freestanding silicon NW with respect to temperature and laser power are recorded. From the analysis of effective laser power absorbed by exposed silicon NW and a detailed Raman study along with the concept of longitudinal heat distribution in silicon NW, the thermal conductivity of the freestanding silicon NW of ∼112 nm diameter is estimated to be ∼53 W m−1 K−
1.
Multibit racetrack memory
Authors: Deger C
Published: September 2020

We present a hybrid usage of domain walls and skyrmions in the same racetrack memory which can enable developing a platform for many-valued magnetic data storage technology, by numerically solving the Landau–Lifshitz-Gilbert equation. The conversion of domain-walls to magnetic skyrmions in a plain nanotrack without geometrical restrictions allowed us to realize a ternary racetrack memory. Annihilation, conversion, and passing over of the reverse domains are considered as the three-state of ternary logic. We anticipate that multibit racetrack memory will influence the development of data storage platforms for emergent computing technologies.
Insight into contraction dynamics of microwave plasmas for CO2 conversion from plasma chemistry modelling
Authors: Viegas P , Vialetto L , Wolf A J , Peeters F J J , Groen P W C , Righart T W H , Bongers W A , van de Sanden M C M , Diomede P
Published: September 2020

This work addresses plasma chemistry in the core of a vortex-stabilized microwave discharge for CO2 conversion numerically, focusing on the pressure-dependent contraction dynamics of this plasma. A zero-dimensional model is presented for experimental conditions in a pressure range between 60 and 300 mbar and a temperature range between 3000 and 6500 K. Monte Carlo flux (MCF) simulations, which describe electron kinetics, are self-consistently coupled to the plasma chemistry model. The simulation results show that an increase in pressure is accompanied by a transition in neutral composition in the plasma core: from a significant amount of CO2 and O2 at low pressures to a O/CO/C mixture at high pressures, the composition being determined mostly by thermal equilibrium and by transport processes. The change of temperature and composition with pressure lead to higher ionisation coefficient and more atomic ion composition in the plasma core. These changes result in an increase in ionisation degree in the plasma core from 10−5 to 10−4. These factors are shown to be fundamental to drive contraction in the CO2 microwave discharge.
Tunable Dirac cones in single-layer selenium
Authors: Chen Zhendong , Hu Yuefang , Zhu Ziming , Zhang Wei
Published: September 2020

Dirac cone, one of the main characters of topological materials, provides us an approach to explore topological phase transitions and topological states. Single-element 2D-Xenes are prominent candidates for hosting Dirac cones. Till now, the multiple Dirac cones, Dirac-like cones, and semi-metal Dirac point have been discovered in them. However, it is still difficult to realize the tunable Dirac cones due to the lack of appropriate materials. Using first-principles calculations, this paper proposes that monolayer selenium with square lattice could achieve tunable Dirac cones and a topological phase transition. Double structural phases of the monolayer selenium can be distinguished according to strain applied, i.e., buckled square and buckled rectangular phases, which have rich Dirac physics. There exist four anisotropic Dirac cones in the buckled square phase, owing to fourfold symmetry. The buckled rectangular phase hosts a topological phase transition from a 2D topological insulator with double Dirac cones to a simple insulator, with a Dirac semi-metal having single Dirac point as the phase transition point. Moreover, the topological insulator has a global band gap of 0.16 eV, suggesting its potential utilizations in room-temperature devices. These studies will greatly promote the development of the Dirac physics and widen the application ranges of 2D-Xenes.
Novel structures and mechanical properties of Zr2N: Ab initio description under high pressures*
Authors: Wen Minru , Xie Xing , Xie Zhixun , Dong Huafeng , Zhang Xin , Wu Fugen , Wang Chong-Yu
Published: September 2020

With the formation of structural vacancies, zirconium nitrides (key materials for cutting coatings, super wear-resistance, and thermal barrier coatings) display a variety of compositions and phases featuring both cation and nitrogen enrichment. This study presents a systematic exploration of the stable crystal structures of zirconium heminitride combining the evolutionary algorithm method and ab initio density functional theory calculations at pressures of 0 GPa, 30 GPa, 60 GPa, 90 GPa, 120 GPa, 150 GPa, and 200 GPa. In addition to the previously proposed phases P42/mnm-, Pnnm-, and Cmcm-Zr2N, five new high-pressure Zr2N phases of P4/nmm, I4/mcm, P21/m,

P

3
¯

m
1

, and C2/m are discovered. An enthalpy study of these candidate configurations reveals various structural phase transformations of Zr2N under pressure. By calculating the elastic constants and phonon dispersion, the mechanical and dynamical stabilities of all predicted structures are examined at ambient and high pressures. To understand the structure–property relationships, the mechanical properties of all Zr2N compounds are investigated, including the elastic moduli, Vickers hardness, and directional dependence of Young’s modulus. The Cmcm-Zr2N phase is found to belong to the brittle materials and has the highest Vickers hardness (12.9 GPa) among all candidate phases, while the I4/mcm-Zr2N phase is the most ductile and has the lowest Vickers hardness (2.1 GPa). Furthermore, the electronic mechanism underlying the diverse mechanical behaviors of Zr2N structures is discussed by analyzing the partial density of states.
Alternative constitutive relation for momentum transport of extended Navier–Stokes equations*
Authors: Han Guo-Feng , Liu Xiao-Li , Huang Jin , Nawnit Kumar , Sun Liang
Published: September 2020

The classical Navier–Stokes equation (NSE) is the fundamental partial differential equation that describes the flow of fluids, but in certain cases, like high local density and temperature gradient, it is inconsistent with the experimental results. Some extended Navier–Stokes equations with diffusion terms taken into consideration have been proposed. However, a consensus conclusion on the specific expression of the additional diffusion term has not been reached in the academic circle. The models adopt the form of the generalized Newtonian constitutive relation by substituting the convection velocity with a new term, or by using some analogy. In this study, a new constitutive relation for momentum transport and a momentum balance equation are obtained based on the molecular kinetic theory. The new constitutive relation preserves the symmetry of the deviation stress, and the momentum balance equation satisfies Galilean invariance. The results show that for Poiseuille flow in a circular micro-tube, self-diffusion in micro-flow needs considering even if the local density gradient is very low.
Thermal stress reduction of GaAs epitaxial growth on V-groove patterned Si substrates*
Authors: Yang Ze-Yuan , Wang Jun , Wu Guo-Feng , Huang Yong-Qing , Ren Xiao-Min , Ji Hai-Ming , Luo Shuai
Published: September 2020

We investigate the thermal stresses for GaAs layers grown on V-groove patterned Si substrates by the finite-element method. The results show that the thermal stress distribution near the interface in a patterned substrate is nonuniform, which is far different from that in a planar substrate. Comparing with the planar substrate, the thermal stress is significantly reduced for the GaAs layer on the patterned substrate. The effects of the width of the V-groove, the thickness, and the width of the SiO2 mask on the thermal stress are studied. It is found that the SiO2 mask and V-groove play a crucial role in the stress of the GaAs layer on Si substrate. The results indicate that when the width of V-groove is 50 nm, the width and the thickness of the SiO2 mask are both 100 nm, the GaAs layer is subjected to the minimum stress. Furthermore, Comparing with the planar substrate, the average stress of the GaAs epitaxial layer in the growth window region of the patterned substrate is reduced by 90%. These findings are useful in the optimal designing of growing high-quality GaAs films on patterned Si substrates.
Nonequilibrium reservoir engineering of a biased coherent conductor for hybrid energy transport in nanojunctions*
Authors: Hu Bing-Zhong , Nian Lei-Lei , Lü Jing-Tao
Published: September 2020

We show that a current-carrying coherent electron conductor can be treated as an effective bosonic energy reservoir involving different types of electron–hole pair excitations. For weak electron–boson coupling, hybrid energy transport between nonequilibrium electrons and bosons can be described by a Landauer-like formula. This allows for unified account of a variety of heat transport problems in hybrid electron–boson systems. As applications, we study the non-reciprocal heat transport between electrons and bosons, thermoelectric current from a cold-spot, and electronic cooling of the bosons. Our unified framework provides an intuitive way of understanding hybrid energy transport between electrons and bosons in their weak coupling limit. It opens the way of nonequilibrium reservoir engineering for efficient energy control between different quasi-particles at the nanoscale.
A new heuristics model of simulating pedestrian dynamics based on Voronoi diagram*
Authors: Wu Xin-Sen , Yue Hao , Liu Qiu-Mei , Zhang Xu , Shao Chun-Fu
Published: September 2020

A new heuristics model based on the Voronoi diagram is presented to simulate pedestrian dynamics with the non-crowded state, in which these mechanisms of preference demand evading and surpassing, microscopic anti-deadlock, and site-fine-tuning are considered. The preference demand describes the willingness determination of detouring or following other pedestrians. In the evading and surpassing mechanisms, in order to achieve a balance between avoiding conflicts and minimizing detour distances, a new pair of concepts: “allow-areas and denial-areas” are introduced to divide the feasible region for pedestrians detour behaviors, in which the direction and magnitude of detour velocity are determined. A microscopic anti-deadlock mechanism is inserted to avoid deadlock problem of the counter-directional pedestrian. A site-fine-tuning mechanism is introduced to describe the behavior of avoiding getting too close to the neighbors in pedestrian movement. The presented model is verified through multiple scenarios, including the uni- or bi-direction pedestrian flow in the corridor without obstacles, the uni-direction pedestrian flow in the corridor with obstacles, and the pedestrian evacuation from a room with single-exit. The simulation results show that the velocity–density relationship is consistent with empirical data. Some self-organizing phenomena, such as lanes formation and arching are observed in the simulation. When pedestrians detour an obstacle, the avoiding area before the obstacle and the unoccupied area after the obstacle can be observed. When pedestrians evacuate through a bottleneck without panic, the fan-shaped crowd can be found, which is consistent with the actual observation. It is also found that the behavior of following others in an orderly manner is more conducive to the improvement of the overall movement efficiency when the crowd moves in a limited space.
Design and development of laser speckle reduction device using waveguide diffuser and pyramidal cavity for projection imaging
Authors: Kumar Virendra , Gupta Mayank , Dubey Atul Kumar , Tayal Shilpa , Singh Veena , Mehta Dalip Singh
Published: September 2020

We report the design and development of an efficient speckle reduction device for projection imaging. The device is composed of a combination of a rod-shaped waveguide diffuser and a reflective pyramidal cavity. The simulation results reveal that the pyramidal cavity with waveguide diffuser is a highly efficient light guide comparable to the other conventional light guides. Further, the device was developed and tested experimentally on the basis of speckle contrast and image quality for both the microscopic and macroscopic objects. An acrylic rod-shaped waveguide diffuser was developed and mounted at the middle of a pyramidal shaped cavity which was fabricated using 3D printer. Four highly reflecting mirrors were installed to make the cavity reflective. The system is highly effective for the speckle suppression due to the coherence reduction via multiple scattering from the rod-shaped waveguide diffuser and multiple reflections from the pyramidal cavity. In the system, a combined effect of spatial and angular diversity along with intensity averaging leads to an effective speckle free uniform illumination. Reduced speckle contrast using the proposed system was observed up to 2%, which is nearly equivalent to mechanically moving diffuser system. The device is able to reduce speckle contrast significantly without using any moving parts and in addition, it does not consume any electrical energy. The proposed system is compact, low cost, efficient, and very effective for low to high power laser sources in speckle reduction. Experimental results are compared with stationary and rotating diffuser system on the basis of computed speckle contrast and image quality.
Physical Activity Buffers the Adverse Impacts of Racial Discrimination on Allostatic Load Among Indigenous Adults
Authors: Copeland Jennifer L , Currie Cheryl L , Chief Moon-Riley Kathrina
Published: September 2020

Background

Racial discrimination has been associated with biological dysfunction among ethnic minorities. The extent to which regular physical activity (PA) may buffer this association is unknown.

Purpose

To examine the association between past-year racial discrimination and allostatic load (AL) stratified by PA within a sample of Indigenous adults.

Methods

Data were collected from Indigenous adults attending university in a city in western Canada between 2015 and 2017. The Experiences of Discrimination Scale was used to assess discrimination and the Godin–Shephard Leisure-Time Physical Activity Questionnaire assessed PA. A composite of seven biomarkers assessing neuroendocrine, cardiovascular, metabolic, and immune system function measured AL. Linear regression models examined associations adjusted for confounders (N = 150).

Results

In the insufficiently active group, every 1 point increase in racial discrimination (up to a maximum of 9) resulted in approximately one third of a point increase in AL score. In the sufficiently active group, the association between racial discrimination and AL score was not statistically significant.

Conclusions

A growing body of research suggests racial discrimination is associated with multisystem biological dysregulation and health risks. Increased action to address racism in society is a priority. As that work unfolds, there is a need to identify effective tools that racialized groups can use to buffer the effects of racism on their health. The present findings suggest that engagement in regular PA may attenuate the pernicious effects of discrimination on biological dysfunction.
Insect–Plant Interactions: A Multilayered Relationship
Authors: Sharma Garima , Malthankar Praful Ashokrao , Mathur Vartika
Published: September 2020

During herbivory, insects recognize their host plant based on specific chemical cues, whereas the plants induce various chemical and morphological defense responses to resist this attack. However, the seemingly bidirectional insect–plant interaction involves various confounding aspects that influence the performance and fitness of the two participants. These interactions are often mediated by associated microbiota, competitors, predators, and parasitoids that interact in either obligate or facultative manner. Insect endosymbionts play a crucial role in the perception, nutrition, metabolism as well as reproduction of their host, which together determine its survival and fitness on the plant. Endosymbionts also help their host to overcome plant defenses by detoxifying plant metabolites. On the contrary, plant-associated microbes contribute in induced systemic plant resistance by enhancing chemical and morphological defense. These interactions determine the association of insect and plant, not only with the high trophic levels but also with the ecosystem as a whole. Thus, insect–plant interaction is a multilayered relationship extending to various micro- and macro-organisms associated either temporally or spatially. All these relationships may be considered to obtain a wholesome perspective of the natural environment.
Hypertension and Comorbidities in Rural and Urban Chinese Older People: An Epidemiological Subanalysis From the SAGE Study
Authors: Li Haitao , Hu Yanhong Jessika , Lin Hualiang , Xia Hui , Guo Yanfei , Wu Fan
Published: September 2020

Background

There is a lack of studies comparing hypertension and comorbidities in rural and urban older people in China. This study aimed to investigate the prevalence of hypertension and comorbidities in older people and to describe differences between patients from rural and urban areas in China.

Methods

A cross-sectional study on global AGEing and adult health (SAGE) was conducted from 2007 to 2010 across 8 provinces in China. The current study included a nationally representative subsample of 7,403 respondents aged 60 years and above. Hypertension was either self-reported diagnosed hypertension or 1 elevated measured blood pressure measurement (≥140/90 mm Hg). Comorbidities were self-reported and included angina, arthritis, asthma, stroke, diabetes, depression, and chronic lung disease.

Results

The prevalence of hypertension was 66.1%. Hypertension associated with 1 comorbidity was recorded in 35.9% of all participants. A large majority (73.6%) of participants with hypertension reported “good” or “very good” general health status. The prevalence of hypertension and the number of comorbidities increased with age. The prevalence rates of multiple comorbidities were higher for urban participants than their rural counterparts (27.8 vs. 42.4% for 1 morbidity; 7.7 vs. 16.4% for 2 comorbidities; 1.4 vs. 4.7% for 3 comorbidities; 0.4 vs. 1.2% for ≥4 comorbidities) after adjustment for sociodemographic factors. However, urban participants reported better general health status, irrespective of the number of comorbidities.

Conclusions

Our study implies that health promotion policies targeting older people should be developed. Rural areas should be a priority, and investment in the quality of health care in rural areas is urgently needed.
Fundamentally different repetitive element composition of sex chromosomes in Rumex acetosa
Authors: Jesionek Wojciech , Bodláková Markéta , Kubát Zdeněk , Čegan Radim , Vyskot Boris , Vrána Jan , Šafář Jan , Puterova Janka , Hobza Roman
Published: September 2020

Background and Aims

Dioecious species with well-established sex chromosomes are rare in the plant kingdom. Most sex chromosomes increase in size but no comprehensive analysis of the kind of sequences that drive this expansion has been presented. Here we analyse sex chromosome structure in common sorrel (Rumex acetosa), a dioecious plant with XY1Y2 sex determination, and we provide the first chromosome-specific repeatome analysis for a plant species possessing sex chromosomes.

Methods

We flow-sorted and separately sequenced sex chromosomes and autosomes in R. acetosa using the two-dimensional fluorescence in situ hybridization in suspension (FISHIS) method and Illumina sequencing. We identified and quantified individual repeats using RepeatExplorer, Tandem Repeat Finder and the Tandem Repeats Analysis Program. We employed fluorescence in situ hybridization (FISH) to analyse the chromosomal localization of satellites and transposons.

Key Results

We identified a number of novel satellites, which have, in a fashion similar to previously known satellites, significantly expanded on the Y chromosome but not as much on the X or on autosomes. Additionally, the size increase of Y chromosomes is caused by non-long terminal repeat (LTR) and LTR retrotransposons, while only the latter contribute to the enlargement of the X chromosome. However, the X chromosome is populated by different LTR retrotransposon lineages than those on Y chromosomes.

Conclusions

The X and Y chromosomes have significantly diverged in terms of repeat composition. The lack of recombination probably contributed to the expansion of diverse satellites and microsatellites and faster fixation of newly inserted transposable elements (TEs) on the Y chromosomes. In addition, the X and Y chromosomes, despite similar total counts of TEs, differ significantly in the representation of individual TE lineages, which indicates that transposons proliferate preferentially in either the paternal or the maternal lineage.
A practical guide to mechanistic systems modeling in biology using a logic-based approach
Authors: Niarakis Anna , Helikar Tomáš
Published: September 2020

Mechanistic computational models enable the study of regulatory mechanisms implicated in various biological processes. These models provide a means to analyze the dynamics of the systems they describe, and to study and interrogate their properties, and provide insights about the emerging behavior of the system in the presence of single or combined perturbations. Aimed at those who are new to computational modeling, we present here a practical hands-on protocol breaking down the process of mechanistic modeling of biological systems in a succession of precise steps. The protocol provides a framework that includes defining the model scope, choosing validation criteria, selecting the appropriate modeling approach, constructing a model and simulating the model. To ensure broad accessibility of the protocol, we use a logical modeling framework, which presents a lower mathematical barrier of entry, and two easy-to-use and popular modeling software tools: Cell Collective and GINsim. The complete modeling workflow is applied to a well-studied and familiar biological process—the lac operon regulatory system. The protocol can be completed by users with little to no prior computational modeling experience approximately within 3 h.