bluuebunny/crossref_metadata_2025 huggingface dataset:
Small angle scattering of diblock copolymers profiled by machine learning
Authors: Tung Chi-Huan , Chang Shou-Yi , Chen Hsin-Lung , Wang Yangyang , Hong Kunlun , Carrillo Jan Michael , Sumpter Bobby G. , Shinohara Yuya , Do Changwoo , Chen Wei-Ren
Published: April 2022

We outline a machine learning strategy for quantitively determining the conformation of AB-type diblock copolymers with excluded volume effects using small angle scattering. Complemented by computer simulations, a correlation matrix connecting conformations of different copolymers according to their scattering features is established on the mathematical framework of a Gaussian process, a multivariate extension of the familiar univariate Gaussian distribution. We show that the relevant conformational characteristics of copolymers can be probabilistically inferred from their coherent scattering cross sections without any restriction imposed by model assumptions. This work not only facilitates the quantitative structural analysis of copolymer solutions but also provides the reliable benchmarking for the related theoretical development of scattering functions.
Controlling the volume fraction of glass-forming colloidal suspensions using thermosensitive host “mesogels”
Authors: Behra J. S. , Thiriez A. , Truzzolillo D. , Ramos L. , Cipelletti L.
Published: April 2022

The key parameter controlling the glass transition of colloidal suspensions is φ, the fraction of the sample volume occupied by the particles. Unfortunately, changing φ by varying an external parameter, e.g., temperature T as in molecular glass formers, is not possible, unless one uses thermosensitive colloidal particles, such as the popular poly(N-isopropylacrylamide) (PNiPAM) microgels. These, however, have several drawbacks, including high deformability, osmotic deswelling, and interpenetration, which complicate their use as a model system to study the colloidal glass transition. Here, we propose a new system consisting of a colloidal suspension of non-deformable spherical silica nanoparticles, in which PNiPAM hydrogel spheres of ∼100−200μm size are suspended. These non-colloidal “mesogels” allow for controlling the sample volume effectively available to the silica nanoparticles and hence their φ, thanks to the T-induced change in mesogels’ volume. Using optical microscopy, we first show that the mesogels retain their ability to change size with T when suspended in Ludox suspensions, similarly as in water. We then show that their size is independent of the sample thermal history such that a well-defined, reversible relationship between T and φ may be established. Finally, we use space-resolved dynamic light scattering to demonstrate that, upon varying T, our system exhibits a broad range of dynamical behaviors across the glass transition and beyond, comparable with those exhibited by a series of distinct silica nanoparticle suspensions of various φ.
An ultra-thin ventilated metasurface with extreme asymmetric absorption
Authors: Zhu Yuanzhou , Long Houyou , Liu Chen , Zhang Haixiao , Cheng Ying , Liu Xiaojun
Published: April 2022

Recent progress in minimizing sound absorbers is driven by their great scientific significance and engineering value; however, compact devices for low-frequency sound are still challenging. Here, we construct an ultra-thin metasurface by parallel connecting resonators with high dissipation loss to a non-resonant reactance-dominated boundary (RDB) with high radiation loss, which realizes extreme absorption asymmetry at the exceptional point of scattering eigenvalue. We develop a parallel transfer matrix method to design the system, and a deep-subwavelength absorber (the operating wavelength is 120 times of its thickness) with 99.2% and 0.5% absorption for sound incident from opposite ports is achieved. The extreme absorption asymmetry is ascribed to the distinct coupling between the RDB and resonant meta-atom in an unbalanced dissipating state with excellent robustness against geometrical reconfigurations originated from the broadband near-unity reflection characteristics of the RDB. In particular, the proposed strategy brings the design of a degree of freedom rather than typical multiple resonant modes, and an extensible prototype showing >90% (<1%) absorptance for left- (right-) incidence within a wavelength from 23.3 to 18 times its thickness is demonstrated.
Limited resource network modeling and its opinion diffusion dynamics
Authors: Li Yuhan , Pi Bin , Feng Minyu
Published: April 2022

The preferential attachment of the Barabási–Albert model has been playing an important role in modeling practical complex networks. The preferential attachment mechanism describes the role of many real systems, which follows the characteristic “the rich get richer.” However, there are some situations that are ignored by the preferential attachment mechanism, one of which is the existence of the limited resource. Vertices with the largest degree may not obtain new edges by the highest probability due to various factors, e.g., in social relationship networks, vertices with quite a lot of relationships may not connect to new vertices since their energy and resource are limited. Hence, the limit for degree growing is proposed in our new network model. We adjust the attachment rule in light of the population growth curve in biology, which considers both attraction and restriction of the degree. In addition, the unaware–aware–unaware opinion diffusion is studied on our proposed network. The celebrity effect is taken into consideration in the opinion diffusion process.
Reflection-type broadband coding metasurfaces for acoustic focusing and splitting
Authors: Zhang Na-Li , Zhao Sheng-Dong , Dong Hao-Wen , Wang Yue-Sheng , Zhang Chuanzeng
Published: April 2022

In this paper, we propose a kind of reflection-type broadband acoustic coding metasurfaces (BACMs), which are composed of two square helical channels and the connected air cavity at the end of the channels. This helical-cavity coupled structure is selected as a logical unit “1,” the pure air hole is set as a logical unit “0,” and the reflective phase difference of the two units is approximately equal to π in a broad frequency range. More importantly, we reveal a somewhat unconventional mechanism of the coupling resonance between the helical channel and the air cavity for the broadband characteristic, which can be hardly realized by the traditional space-coiling or Helmholtz-resonator metasurfaces. We prove that the 0/1 encoding form can be reconstructed simply by inserting the spiral structure or not. By encoding the sequence of the logical units in the BACMs, the broadband acoustic focusing lens and acoustic splitter within the frequency range of [2.4, 5.6 kHz] are demonstrated numerically and experimentally. Our study may find applications in the fields of acoustic wave devices.
Solution-processed MAPbI3/Cs2AgBiBr6 heterostructure through epitaxial growth for broadband photo-detection
Authors: Wang Mengrou , Xu Yubing , Wang Xin , Li Yuwei , Zhao Jingda , Pan Yuzhu , Chen Jing , Li Qing , Zhao Zhiwei , Wu Jun , Lei Wei
Published: April 2022

All-inorganic halide semiconductors with perovskite or perovskite-like structure have aroused a widespread concern recently for its environmental friendliness and stabilities while possessing excellent optoelectronic properties. Double perovskite Cs2AgBiBr6 single crystal (SC) is one of the most representative materials in the latest research area. To further improve the device response range and decrease its dark current density effectively, functional layers based on the solution-processed epitaxial method are normally fabricated as heterojunctions. Herein, a novel idea of a broadband heterojunction MAPbI3 (MA = CH3NH3)/Cs2AgBiBr6 is proposed in this work to achieve this goal. A MAPbI3 layer is fabricated on Cs2AgBiBr6 SC substrates through immersing Cs2AgBiBr6 SC into MAPbI3 solution at a MAPbI3 crystallization temperature. Ultimately, this heterojunction device expands the absorption limit from 618 to 838 nm, makes responsivity range redshift from 629 to 860 nm, and achieves a responsivity of 16.8 mA W−1 while the detectivity of 1.33 × 1011 Jones under 622 nm 0.55 mW cm−2 illumination at −20 V bias, maintaining excellent optoelectronic properties.
Oscillation of the shock train under synchronous variation of incoming Mach number and backpressure
Authors: Wang Ziao , Chang Juntao , Li Yiming , Chen Ruoyu , Hou Wenxin , Guo Jifeng , Yue Lianjie
Published: April 2022

Experiments were conducted to characterize shock train oscillation under the simultaneous variation of the incoming Mach number and backpressure. Under steady and low-frequency oscillatory backpressure (2 Hz), the incoming Mach number varied from 1.8 to 2.4. According to the intersection of downgoing background wave with bottom front leg, Mach stem, and top front leg of the normal shock train leading edge, the normal shock train/background wave interaction can be divided into three types. Two types of oblique shock train/background wave interaction exist. The downgoing (upgoing) background wave upstream of the oblique shock train can cause the upgoing (downgoing) shock in the shock train leading edge to become the dominated shock. Two modes of shock train oscillation were found: oscillation mode 1, in which the shock train oscillated in the favorable gradient region of the relaxing boundary layer, and oscillation mode 2, where the shock train enters the adverse pressure gradient region caused by the impingement of background wave. Compared with mode 1, mode 2 leads to a larger upstream movement of the shock train and more intense pressure fluctuation. The oscillation of the shock train is caused by instability in the separation region behind the shock train leading edge. The oscillatory backpressure only affected the motion of shock train during each oscillation period. The overall movement trend of shock train is determined by the incoming Mach number and the mean value of backpressure. The increase of incoming Mach number and backpressure can lead to the enhancement of shock train oscillation.
A non-hierarchical correlation discrete variable representation
Authors: Ellerbrock Roman , Manthe Uwe
Published: April 2022

The correlation discrete variable representation (CDVR) facilitates (multi-layer) multi-configurational time-dependent Hartree (MCTDH) calculations with general potentials. It employs a layered grid representation to efficiently evaluate all potential matrix elements appearing in the MCTDH equations of motion. The original CDVR approach and its multi-layer extension show a hierarchical structure: the size of the grids employed at the different layers increases when moving from an upper layer to a lower one. In this work, a non-hierarchical CDVR approach, which uses identically structured quadratures at all layers of the MCTDH wavefunction representation, is introduced. The non-hierarchical CDVR approach crucially reduces the number of grid points required, compared to the hierarchical CDVR, shows superior scaling properties, and yields identical results for all three representations showing the same topology. Numerical tests studying the photodissociation of NOCl and the vibrational states of CH3 demonstrate the accuracy of the non-hierarchical CDVR approach.
An analysis of fatalities from forest fires in China, 1951–2018
Authors: Zong Xuezheng , Tian Xiaorui , Yao Qichao , Brown Peter M.
Published: April 2022

The frequent occurrence of fatalities from wildfires is an ongoing problem in China, even though great improvements have been achieved in overall wildfire management in recent years. We analysed the occurrence patterns and correlative environments of fatalities from forest fires in China from 1951 to 2018. Changes in fire policies affected changes in the numbers of fires, forest area burned and number of fatalities before and after 1987, after the large Great Black Dragon Fire that burned in the Daxing’anling Mountains in northeastern China. Most fatalities occurred in the southern, southwestern and eastern forest regions of the country where population centres are concentrated, while most of the burned area was distributed in forests of northeast China with fewer population centres. Fatalities were correlated with higher values of fire weather indices, coniferous forests, coniferous and broad-leaved mixed forests, moderate–average slopes (5.1–15°), and primarily small fires of less than 100 ha in area. These results should be a first step to help improve awareness of inherent dangers during wildfires and to assist fire managers and policy-makers in strengthening safety procedures for both professional firefighters and the public to reduce wildfire fatalities in the future.
A role for endoplasmic reticulum dynamics in the cellular distribution of microtubules
Authors: Tikhomirova Maria S. , Kadosh Avihay , Saukko-Paavola Aksel J. , Shemesh Tom , Klemm Robin W.
Published: April 2022

Significance

The endoplasmic reticulum (ER) and the microtubule (MT) cytoskeleton form a coextensive, dynamic system that pervades eukaryotic cells. The shape of the ER is generated by a set of evolutionarily conserved membrane proteins that are able to control ER morphology and dynamics independently of MTs. Here we uncover that the molecular machinery that determines ER network dynamics can influence the subcellular distribution of MTs. We show that active control of local ER tubule junction density by ER tethering and fusion is important for the spatial organization of the combined ER–MT system. Our work suggests that cells might alter ER junction dynamics to drive formation of MT bundles, which are important structures, e.g., in migrating cells or in neuronal axons.
Observation of Weyl exceptional rings in thermal diffusion
Authors: Xu Guoqiang , Li Wei , Zhou Xue , Li Huagen , Li Ying , Fan Shanhui , Zhang Shuang , Christodoulides Demetrios N. , Qiu Cheng-Wei
Published: April 2022

Significance

Thermal diffusion is dissipative and strongly related to non-Hermitian physics. At the same time, non-Hermitian Weyl systems have spurred tremendous interest across photonics and acoustics. This correlation has been long ignored and hence shed little light upon the question of whether the Weyl exceptional ring (WER) in thermal diffusion could exist. Intuitively, thermal diffusion provides no real parameter dimensions, thus prohibiting a topological nature and WER. This work breaks this perception by imitating synthetic dimensions via two spatiotemporal advection pairs. The WER is achieved in thermal diffusive systems. Both surface-like and bulk states are demonstrated by coupling two WERs with opposite topological charges. These findings extend topological notions to diffusions and motivate investigation of non-Hermitian diffusive and dissipative control.
Concentration gradients in evaporating binary droplets probed by spatially resolved Raman and NMR spectroscopy
Authors: Bell Alena K. , Kind Jonas , Hartmann Maximilian , Kresse Benjamin , Höfler Mark V. , Straub Benedikt B. , Auernhammer Günter K. , Vogel Michael , Thiele Christina M. , Stark Robert W.
Published: April 2022

Significance

Imagine you spill your drink and miss some spots when cleaning up. The next morning you notice that the stains look quite different on different surfaces. What has happened? In droplets of liquid mixtures, the components evaporate at different rates, which leads to gradients in concentration and surface tension. These gradients can cause, for example, so-called Marangoni flows, which in turn affect the evaporation process. To better understand evaporation-induced liquid flows, the concentration gradients have to be measured without disturbing the liquid. Marker molecules might be surface-active or even may affect the evaporation process. We report here on marker-free and contactless measurements of concentrations by spatially resolved Raman and NMR spectroscopy in evaporating binary droplets.
Prenatal disruption of blood–brain barrier formation via cyclooxygenase activation leads to lifelong brain inflammation
Authors: Zhao Qiuying , Dai Weiye , Chen Hui Yu , Jacobs Russell E. , Zlokovic Berislav V. , Lund Brett T. , Montagne Axel , Bonnin Alexandre
Published: April 2022

Significance

This study demonstrates that maternal inflammation during pregnancy perturbs blood–brain barrier formation via cyclooxygenase activation in fetal microglia, leading to abnormal cerebrovascular function and chronic brain inflammation persisting across the offspring life span. Therefore, developmental disruption of blood–brain barrier formation could be an important etiological factor contributing to the pathology of neurodevelopmental disorders.
Small mammal personalities generate context dependence in the seed dispersal mutualism
Authors: Brehm Allison M. , Mortelliti Alessio
Published: April 2022

Significance

Mutualisms are foundational components of ecosystems and give rise to essential services such as seed dispersal and pollination. Ecologists believe that nearly every species is involved in one or more mutualisms, but it is unknown how consistent behavioral differences among individuals, or personalities, may influence an individual’s role. We scored individuals on a continuum from antagonistic to mutualistic given their contributions to the seed dispersal mutualism and found that personalities affect the extent to which individuals are mutualistic. These findings suggest a novel mechanism generating context dependence in mutualisms and underscore the need to incorporate behavioral diversity into conservation and restoration efforts.
Biodiversity effects of food system sustainability actions from farm to fork
Authors: Read Quentin D. , Hondula Kelly L. , Muth Mary K.
Published: April 2022

Significance

The food system’s negative impact on biodiversity is increasing over time. Conserving biodiversity requires immediate and widespread action to reduce the biodiversity footprint of food consumption, but biodiversity has historically been neglected in sustainability assessments. We combine high-resolution estimates of the biodiversity footprint with food system scenario modeling to predict the consequences of two key food system sustainability actions in the United States: diet shifts and food waste reduction. Taking these actions may benefit biodiversity in some places and harm it in others. The results of this study can help decision makers understand the trade-offs we must navigate to balance human health, economics, and environmental sustainability and help consumers understand how their diets and food waste behaviors influence global biodiversity.
Natural gas of radiolytic origin: An overlooked component of shale gas
Authors: Naumenko-Dèzes Maria , Kloppmann Wolfram , Blessing Michaela , Bondu Raphaël , Gaucher Eric C. , Mayer Bernhard
Published: April 2022

Significance

Natural gas is a key fossil fuel as the world transitions away from coal toward less polluting energy sources in an attempt to minimize the impact of global climate change. Historically, the origin of natural gas produced from conventional reservoirs has been determined based on gas compositional data and stable isotope fingerprints of methane, ethane, and highern-alkanes, revealing three dominant sources of natural gas: microbial, thermogenic, and abiotic. In our detailed synthesis of published natural gas data from a variety of unconventional hydrocarbon reservoirs worldwide, we demonstrate that there is a previously overlooked source of natural gas that is generated by radiolysis of organic matter in shales.
Massively parallel, computationally guided design of a proenzyme
Authors: Yachnin Brahm J. , Azouz Laura R. , White Ralph E. , Minetti Conceição A. S. A. , Remeta David P. , Tan Victor M. , Drake Justin M. , Khare Sagar D.
Published: April 2022

Significance

Proteins have shown promise as therapeutics and diagnostics, but their effectiveness is limited by our inability to spatially target their activity. To overcome this limitation, we developed a computationally guided method to design inactive proenzymes or zymogens, which are activated through cleavage by a protease. Since proteases are differentially expressed in various tissues and disease states, including cancer, these proenzymes could be targeted to the desired microenvironment. We tested our method on the therapeutically relevant protein carboxypeptidase G2 (CPG2). We designed Pro-CPG2s that are inhibited by 80 to 98% and are partially to fully reactivatable following protease treatment. The developed methodology, with further refinements, could pave the way for routinely designing protease-activated protein-based therapeutics and diagnostics that act in a spatially controlled manner.
Transport features predict if a molecule is odorous
Authors: Mayhew Emily J. , Arayata Charles J. , Gerkin Richard C. , Lee Brian K. , Magill Jonathan M. , Snyder Lindsey L. , Little Kelsie A. , Yu Chung Wen , Mainland Joel D.
Published: April 2022

Significance

What makes a molecule have a smell? This simple question represents a significant gap in our understanding of olfaction. To answer it, we trained models to predict whether molecules were odorous based on molecular characteristics and noted which characteristics were needed to make correct predictions. We found that molecules with sufficient volatility and hydrophobicity are generally odorous, which suggests that reaching olfactory receptors is the dominant barrier for prospective olfactory stimuli. Based on these criteria, there are billions of molecules that are likely odorous but have never been smelled. We can now recognize an odorous molecule from its structure, and this guides us to discover new classes of odorants and include all types of odorants in our study of smell.
Gain of function due to increased opening probability by two
KCNQ5
pore variants causing developmental and epileptic encephalopathy
Authors: Nappi Mario , Barrese Vincenzo , Carotenuto Lidia , Lesca Gaetan , Labalme Audrey , Ville Dorothee , Smol Thomas , Rama Mélanie , Dieux-Coeslier Anne , Rivier-Ringenbach Clotilde , Soldovieri Maria Virginia , Ambrosino Paolo , Mosca Ilaria , Pusch Michael , Miceli Francesco , Taglialatela Maurizio
Published: April 2022

Significance

Variants in genes encoding neuronally expressed potassium channel subunits are frequent causes of developmental and epileptic encephalopathies (DEEs). Characterization of their functional consequences is critical to confirm diagnosis, assess prognosis, and implement personalized treatments. In the present work, we describe two patients carrying variants in
KCNQ5
, a gene very recently and rarely found involved in DEEs, and reveal that they both cause remarkable gain-of-function consequences on channel activity. A PIP
2
-independent increase in open probability, without effects on membrane abundance or single-channel conductance, was responsible for the observed mutation-induced functional changes, thus revealing a pathomolecular disease mechanism for DEEs.
Face neurons encode nonsemantic features
Authors: Bardon Alexandra , Xiao Will , Ponce Carlos R. , Livingstone Margaret S. , Kreiman Gabriel
Published: April 2022

Significance

Face neurons, which fire more strongly in response to images of faces than to other objects, are a paradigmatic example of object selectivity in the visual cortex. We asked whether such neurons represent the semantic concept of faces or, rather, visual features that are present in faces but do not necessarily count as a face. We created synthetic stimuli that strongly activated face neurons and showed that these stimuli were perceived as clearly distinct from real faces. At the same time, these synthetic stimuli were slightly more often associated with faces than other objects were. These results suggest that so-called face neurons do not represent a semantic category but, rather, represent visual features that correlate with faces.
Reduction of free-roaming cat population requires high-intensity neutering in spatial contiguity to mitigate compensatory effects
Authors: Gunther Idit , Hawlena Hadas , Azriel Lior , Gibor Dan , Berke Olaf , Klement Eyal
Published: April 2022

Significance

Although popular companion animals, domestic cats pose numerous problems when free-roaming, including predation of wildlife, hazards to humans, impaired sanitation, and a decrease in their welfare. Thus, managing their populations is essential. The trap–neuter–return method (TNR; capturing, sterilizing, returning/releasing) is widely employed for managing cat populations. However, there is a lack of long-term controlled evidence for its effectiveness. We examined the outcomes of high-intensity TNR by performing a 12-y controlled field experiment. Neutering over 70% of the cats caused population decline when applied over contiguous areas. However, it was limited by a rebound increase in reproduction and survival. These findings provide a robust quantification of the limitations and the long-term effectiveness of TNR.
Active unfolding of the glucocorticoid receptor by the Hsp70/Hsp40 chaperone system in single-molecule mechanical experiments
Authors: Moessmer Patrick , Suren Thomas , Majdic Ulrike , Dahiya Vinay , Rutz Daniel , Buchner Johannes , Rief Matthias
Published: April 2022

Significance

One of the key unresolved questions in the field of molecular chaperones is how they can actively unfold proteins. In this study, we discovered that the Hsp70/Hsp40 chaperone system completely unfolds a native soluble substrate protein, the ligand-binding domain of the glucocorticoid receptor, in a concerted action. Our high-resolution optical tweezers data show in real time how the substrate is attacked by the chaperone machinery. As soon as the hormone has left the binding pocket, up to five Hsp70/Hsp40 complexes bind and unfold the protein in a stepwise manner. This finding constitutes direct evidence that the chaperone machinery can bind to the folded core of the receptor, thus providing a mechanism for Hsp70-induced protein unfolding.
Generic character of charge and spin density waves in superconducting cuprates
Authors: Lee Sangjun , Huang Edwin W. , Johnson Thomas A. , Guo Xuefei , Husain Ali A. , Mitrano Matteo , Lu Kannan , Zakrzewski Alexander V. , de la Peña Gilberto A. , Peng Yingying , Huang Hai , Lee Sang-Jun , Jang Hoyoung , Lee Jun-Sik , Joe Young Il , Doriese William B. , Szypryt Paul , Swetz Daniel S. , Chi Songxue , Aczel Adam A. , MacDougall Gregory J. , Kivelson Steven A. , Fradkin Eduardo , Abbamonte Peter
Published: April 2022

Significance

The essential physics of the cuprate high-temperature superconductors have been a central focus of condensed-matter physics for more than three decades. Although initially controversial, it is now clear that a ubiquitous tendency toward charge-density-wave (CDW) order is intertwined with the superconductivity. However, this manifests differently in distinct cuprates. On the basis of extensive X-ray and neutron scattering studies of the temperature and doping dependence of the CDW and spin-density-wave (SDW) correlations in one representative cuprate and a comparison with existing studies on other cuprates, we show that there plausibly is a single, preferred CDW order at the microscale, whose manifestation at low temperatures is modified in predictable ways by material-specific details, including its interaction with SDW order.
Cryo-EM structure of RNA-induced tau fibrils reveals a small C-terminal core that may nucleate fibril formation
Authors: Abskharon Romany , Sawaya Michael R. , Boyer David R. , Cao Qin , Nguyen Binh A. , Cascio Duilio , Eisenberg David S.
Published: April 2022

In neurodegenerative diseases including Alzheimer’s and amyotrophic lateral sclerosis, proteins that bind RNA are found in aggregated forms in autopsied brains. Evidence suggests that RNA aids nucleation of these pathological aggregates; however, the mechanism has not been investigated at the level of atomic structure. Here, we present the 3.4-Å resolution structure of fibrils of full-length recombinant tau protein in the presence of RNA, determined by electron cryomicroscopy (cryo-EM). The structure reveals the familiar in-register cross-β amyloid scaffold but with a small fibril core spanning residues Glu391 to Ala426, a region disordered in the fuzzy coat in all previously studied tau polymorphs. RNA is bound on the fibril surface to the positively charged residues Arg406 and His407 and runs parallel to the fibril axis. The fibrils dissolve when RNase is added, showing that RNA is necessary for fibril integrity. While this structure cannot exist simultaneously with the tau fibril structures extracted from patients’ brains, it could conceivably account for the nucleating effects of RNA cofactors followed by remodeling as fibrils mature.
Interacting pest control and pollination services in coffee systems
Authors: Martínez-Salinas Alejandra , Chain-Guadarrama Adina , Aristizábal Natalia , Vilchez-Mendoza Sergio , Cerda Rolando , Ricketts Taylor H.
Published: April 2022

Significance

Food production depends on biodiversity and ecosystem services (ES) such as pest control and pollination. Our knowledge about biodiversity benefits to crop production has increased in recent decades, but most studies treat ES separately and then add up their values. Ignoring that these services, being part of the same system, likely interact is blinding us to potential synergies and trade-offs. Our field experiment shows, at realistic field scales, that pest control and pollination can interact positively. This synergy translates directly to improved yields and income for coffee farmers, who produce a global commodity worth $24 billion per year. Our findings highlight the need to study interactions to understand the linkages between biodiversity, ES, and farmers’ livelihoods.
Transmogrification of ocean into continent: implications for continental evolution
Authors: Morgan Jason P. , Vannucchi Paola
Published: April 2022

Significance

This study proposes a geological mechanism for creating continental crust and lithosphere. When continents collide, the typical embayments and protrusions along their rifted margins make it likely that fragments of seafloor will be trapped within the growing mountain belt. These become preferential centers of sedimentation that eventually convert former seafloor into a unique form of continental crust and lithosphere, leading to characteristic temporal changes in the relative strength and uplift/subsidence of these regions. The Alpine–Himalayan mountain chain in Eurasia shows several stages of this process, which we further explore with a one-dimensional thermal-rheological model. In Asia, this process appears to have created a characteristic paired-mountain belt geomorphology (Himalaya/Tibet + Tian Shan) that has greatly strengthened the East Asian Monsoon.
Investigation of three topological edge states in honeycomb lattices based on graphene plasmonic crystal
Authors: Li Zhi , He Zhen , Zhuo Liqiang , Su Shaojian , Lin Zhili , Qiu Weibin , Huang Beiju , Kan Qiang
Published: April 2022

In this article, three categories of the edge states in the honeycomb lattice are investigated theoretically by using the effective tight-binding Hamiltonian. The edge-bulk corresponding dispersions of zigzag, bearded, and armchair edge states analytically. The actual edge-bulk corresponding and the light field distribution of the graphene plasmonic crystals are obtained by solving Maxwell equations with boundary conditions, which are in good agreement with the analytical results. The proposed plasmonic structures provide guidance for designing the frequency range dependent property of topological structures, and show the potential applications in topological robust devices.
Study the mixed valence problem in asymmetric Anderson model: Fano–Kondo resonance around Fermi level
Authors: Li ZhenHua , Cheng YongXi , Zheng Xiao , Wei JianHua , Yan YiJing , Luo Hong-Gang
Published: April 2022

We numerically calculate the local density of states (LDOS) in asymmetric Anderson model in mixed valence regime using hierarchical equations of motion approach. Based on the idea that the asymmetric line shape of LDOS around Fermi level stems from the interference between the single particle resonance and the Kondo resonance, we perform a fitting. From the fitting results, we obtain the Kondo temperatures and the Fano factors with changing the single particle energy. The tendency of Kondo temperature agrees with the previous analytic expressions and the Fano factors are in an expected variation of Fano resonance. Our study shows that the Fano–Kondo resonance can reasonably explain the asymmetric line shape of the LDOS around the Fermi level.
On the fly swapping algorithm for ordering of degrees of freedom in density matrix renormalization group
Authors: Li Weitang , Ren Jiajun , Yang Hengrui , Shuai Zhigang
Published: April 2022

Density matrix renormalization group (DMRG) and its time-dependent variants have found widespread applications in quantum chemistry, including ab initio electronic structure of complex bio-molecules, spectroscopy for molecular aggregates, and charge transport in bulk organic semiconductors. The underlying wavefunction ansatz for DMRG, matrix product state (MPS), requires mapping degrees of freedom (DOF) into a one-dimensional topology. DOF ordering becomes a crucial factor for DMRG accuracy. In this work, we propose swapping neighboring DOFs during the DMRG sweeps for DOF ordering, which we term ‘on the fly swapping’ (OFS) algorithm. We show that OFS is universal for both static and time-dependent DMRG with minimum computational overhead. Examples are given for one dimensional antiferromagnetic Heisenberg model, ab initio electronic structure of N2 molecule, and the S1/S2 internal conversion dynamics of pyrazine molecule. It is found that OFS can indeed improve accuracy by finding better DOF ordering in all cases.
EPSPatNet86: eight-pointed star pattern learning network for detection ADHD disorder using EEG signals
Authors: Tanko Dahiru , Barua Prabal Datta , Dogan Sengul , Tuncer Turker , Palmer Elizabeth , Ciaccio Edward J , Acharya U Rajendra
Published: April 2022

Objective. The main objective of this work is to present a hand-modelled one-dimensional signal classification system to detect Attention-Deficit Hyperactivity Disorder (ADHD) disorder using electroencephalography (EEG) signals. Approach. A novel handcrafted feature extraction method is presented in this research. Our proposed method uses a directed graph and an eight-pointed star pattern (EPSPat). Also, tunable q wavelet transforms (TQWT), wavelet packet decomposition (WPD), statistical extractor, iterative Chi2 (IChi2) selector, and the k-nearest neighbors (kNN) classifier have been utilized to develop the EPSPat based learning model. This network uses two wavelet decomposition methods (TQWT and WPD), and 85 wavelet coefficient bands are extracted. The proposed EPSPat and statistical feature creator generate features from the 85 wavelet coefficient bands and the original EEG signal. The learning network is termed EPSPatNet86. The main purpose of the presented EPSPatNet86 is to detect abnormalities of the EEG signals. Therefore, 85 wavelet subbands have been generated to extract features. The created 86 feature vectors have been evaluated using the Chi2 selector and the kNN classifier in the loss value calculation phase. The final features vector is created by employing a minimum loss-valued eight feature vectors. The IChi2 selector selects the best feature vector, which is fed to the kNN classifier. An EEG signal dataset has been used to demonstrate the presented model’s EEG signal classification ability. We have used an ADHD EEG dataset since ADHD is a commonly seen brain-related ailment. Main results. Our developed EPSPatNet86 model can detect the ADHD EEG signals with 97.19% and 87.60% accuracy using 10-fold cross and subject-wise validations, respectively. Significance. The calculated results demonstrate that the presented EPSPatNet86 attained satisfactory EEG classification ability. Results show that we can apply our developed EPSPatNet86 model to other EEG signal datasets to detect abnormalities.
Neural network flows of low q-state Potts and clock models
Authors: Giataganas Dimitrios , Huang Ching-Yu , Lin Feng-Li
Published: April 2022

It is known that a trained restricted Boltzmann machine (RBM) on the binary Monte Carlo Ising spin configurations, generates a series of iterative reconstructed spin configurations which spontaneously flow and stabilize to the critical point of physical system. Here we construct a variety of neural network (NN) flows using the RBM and (variational) autoencoders, to study the q-state Potts and clock models on the square lattice for q = 2, 3, 4. The NN are trained on Monte Carlo spin configurations at various temperatures. We find that the trained NN flow does develop a stable point that coincides with critical point of the q-state spin models. The behavior of the NN flow is nontrivial and generative, since the training is unsupervised and without any prior knowledge about the critical point and the Hamiltonian of the underlying spin model. Moreover, we find that the convergence of the flow is independent of the types of NNs and spin models, hinting a universal behavior. Our results strengthen the potential applicability of the notion of the NN flow in studying various states of matter and offer additional evidence on the connection with the renormalization group flow.
Astrometric Precision Tests on TESS Data
Authors: Gai M. , Vecchiato A. , Riva A. , Busonero D. , Lattanzi M. , Bucciarelli B. , Crosta M. , Qi Z.
Published: April 2022

Astrometry at or below the microarcsec level with an imaging telescope assumes that the uncertainty on the location of an unresolved source can be an arbitrarily small fraction of the detector pixel, given a sufficient photon budget. This paper investigates the geometric limiting precision, in terms of CCD pixel fraction, achieved by a large set of star field images, selected among the publicly available science data of the Transiting Exoplanet Survey Satellite (TESS) mission. The statistics of the distance between selected bright stars (G ≃ 5 mag), in pixel units, is evaluated, using the position estimate provided in the TESS light curve files. The dispersion of coordinate differences appears to be affected by long term variation and noisy periods, at the level of 0.01 pixel. The residuals with respect to low-pass filtered data (tracing the secular evolution), which are interpreted as the experimental astrometric noise, reach the level of a few milli-pixel or below, down to 1/5900 pixel. Saturated images are present, evidencing that the astrometric precision is mostly preserved across the CCD columns, whereas it features a graceful degradation in the along column direction. The cumulative performance of the image set is a few micropixel across columns, or a few 10 μpx along columns. The idea of astrometric precision down to a small fraction of a CCD pixel, given sufficient signal to noise ratio, is confirmed by real data from an in-flight science instrument to the 10−6 pixel level. Implications for future high precision astrometry missions are briefly discussed.
The Renovated Thacher Observatory and First Science Results
Authors: Swift Jonathan J. , Andersen Karina , Arculli Toby , Browning Oakley , Ding Jeffrey , Edwards Nick , Fanning Tomás , Geyer John , Huber Grace , Jin-Ngo Dylan , Kelliher Ben , Kirkpatrick Colin , Kirkpatrick Liam , Klink Douglas , Lavine Connor , Lawrence George , Lawrence Yousef , Cyrus Leung Feng Lin , Luebbers Julien , Myles Justin , O’Neill Theo J. , Osuna Jaime , Phipps Peter , Rahman Gazi , Rosenbaum Teddy , Stacey Holland , Stacey Piper , Tang Hadrien , Wood Asher , Wilcox Alejandro , Vyhnal Christopher R. , Yang Grace , Yim Jennifer , Yin Yao , Zhang Jack , Foley Ryan J. , Gardner Paul , Stafford Greg , Rowe David , Ivarsen Kevin , Hedrick Richard
Published: April 2022

Located on the campus of the Thacher School in Southern California, the Thacher Observatory has a legacy of astronomy research and education that dates back to the late 1950s. In 2016, the observatory was fully renovated with upgrades including a new 0.7 m telescope, a research grade camera, and a slit dome with full automation capabilities. The low-elevation site is bordered by the Los Padres National Forest and therefore affords dark to very dark skies allowing for accurate and precise photometric observations. We present a characterization of the site including sky brightness, weather, and seeing, and we demonstrate the on-sky performance of the facility. Our primary research programs are based around our multi-band photometric capabilities and include photometric monitoring of variable sources, a nearby supernova search and followup program, a quick response transient followup effort, and exoplanet and eclipsing binary light curves. Select results from these programs are included in this work which highlight the broad range of science available to an automated observatory with a moderately sized telescope.
Embedding decomposition for artifacts removal in EEG signals
Authors: Yu Junjie , Li Chenyi , Lou Kexin , Wei Chen , Liu Quanying
Published: April 2022

Objective. Electroencephalogram (EEG) recordings are often contaminated with artifacts. Various methods have been developed to eliminate or weaken the influence of artifacts. However, most of them rely on prior experience for analysis. Approach. Here, we propose an deep learning framework to separate neural signal and artifacts in the embedding space and reconstruct the denoised signal, which is called DeepSeparator. DeepSeparator employs an encoder to extract and amplify the features in the raw EEG, a module called decomposer to extract the trend, detect and suppress artifact and a decoder to reconstruct the denoised signal. Besides, DeepSeparator can extract the artifact, which largely increases the model interpretability. Main results. The proposed method is tested with a semi-synthetic EEG dataset and a real task-related EEG dataset, suggesting that DeepSeparator outperforms the conventional models in both EOG and EMG artifact removal. Significance. DeepSeparator can be extended to multi-channel EEG and data with any arbitrary length. It may motivate future developments and application of deep learning-based EEG denoising. The code for DeepSeparator is available at https://github.com/ncclabsustech/DeepSeparator.
Dye degradation efficiency of green synthesized NiO@GO nanocomposite with biological application
Authors: Subashini K. , Prakash S. , Anusuya Devi V.S. , Sujatha V.
Published: April 2022

The photocatalytic activity of green synthesized nickel oxide nanoparticles derived using Sterculia foetida leaf extract was examined by introducing into graphene oxide (GO). Graphene oxide has porous nature which might enlarge the photocatalytic execution of NiO nanoparticles. NiO nanoparticles (NiO NPs) were prepared by solution combustion method and introduced into graphene oxide (GO) synthesized by Hummers method to form NiO@GO nanocomposite. Various techniques were used for the material characterization of the above synthesized compounds such as UV, FTIR, Powder X-ray diffraction (PXRD), Transmission electron microscopy (TEM). The photocatalytic execution of NiO@GO nanocomposite on deterioration of Methylene blue (MB) and Malachite Green (MG) have been examined and the results indicate that the GO plays a critical part in the improvement of photocatalytic execution. Antibacterial activity has been carried out against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The synthesized NiO@GO nanocomposite accomplishes a most extreme decay efficiency of 98% for Methylene blue than Malachite green under UV-light.
Surface treatment of magnetron-sputtered tantalum pentoxide coatings and its effect on the phenotype and function of immune cells in vitro
Authors: Donkov N , Zykova A , Safonov V , Dudin S , Yakovin S , Goltsev A , Dubrava T
Published: April 2022

The effect was analyzed of surface treatment by argon ions and electron beam on the properties of tantalum pentoxide coatings deposited by reactive magnetron sputtering and the treatment’s correlation with immune cells response. The characteristics of the coatings were determined by means of energy dispersive X-ray (EDX) scanning electron microscopy (SEM), X-ray photoemission spectroscopy (XPS), and atomic force microscopy (AFM). The results demonstrate that the electron-irradiation post-treatment process stimulates the adhesive potential and phagocytic activity of antigen-presenting cells.
Double-discharge plasma system for deposition of carbon nanostructures
Authors: Marinov S , Vachkov V , Ivanov I , Kiss’ovski Zh
Published: April 2022

Deposition of carbon nanostructures from ethanol precursor at atmospheric pressure can be enhanced via the use of a double-discharge system - a microwave and a DC discharge. We used a surface-wave discharge at a frequency of 2.45 GHz in a gas mixture of Ar, H2 and C2H5OH to create a plasma column in a small-diameter ceramic tube and a plasma plume above it. The plume spectra in the UV/Vis range were measured by an optical system with an iHR550 spectrometer; the gas temperature and the electron temperature and density were calculated from the emission lines. The high gas temperature T
g ∼3000 K and electron density (∼6×1020 m3) in the microwave plasma plume cause an effective dissociation of the ethanol even at low levels of absorbed power (10 W) and a strong carbon Swan band is registered in the spectrum. Transporting the created neutral and charged particles to the substrate at atmospheric pressure is difficult due to their short mean-free-path; we, therefore, applied an additional DC discharge. This two-discharge system allows more reactive species and ions from the ethanol decomposition to reach the substrate, thus speeding up the deposition of carbon nanostructures. Such structures were deposited on Ni foil and Ni foam substrates under fixed plasma parameters and controlled substrate temperature. The morphology of the produced graphene structures was studied using SEM and Raman spectroscopy.
Cirrus-cloud conditioned ratio of multiple-to-single backscatter atmospheric phase functions
Authors: Evgenieva Ts , Anguelov V , Gurdev L
Published: April 2022

The present work is related to LIDAR remote sensing of the atmosphere in the presence of cirrus clouds (CC) along the LIDAR line of sight (LOS), when the multiple-backscatter component of the LIDAR return may be essential. E. Eloranta has found analytical expressions of the multiple-backscatter components of different orders as containing the corresponding ratios of the multiple-to-single backscatter phase functions of the backward scattering medium. As a main purpose of this work, we estimated the above-mentioned ratios in cases of backscattering from air and CC, using accurate approximations of the single-scattering phase functions obtained by U. Wandinger. The results obtained show that the multiple-to-single backscatter phase function ratios for air are equal to unity, while for CCs they are quite near unity.
Development of lidar for remote methane sensing using an optimal configuration of high-power laser diodes
Authors: Pencheva V , Penchev S , Dreischuh T
Published: April 2022

A broadband differential absorption lidar (DIAL) is developed making us of the properties of high-power pulsed laser diodes for the purpose of monitoring methane, a major atmospheric greenhouse biogas. The detection range is optimized for the CH4 Q-branch 2v3 overtone spectrum centered at 1.667 μm and mixed with water-vapor absorption bands of. The resonance absorption evaluated of the DIAL signal is an integral sum of the multiple CH4 resonance absorption lines modulating the characteristic broad laser line and simultaneously compensating the interfering water-vapor absorption. A compact DIAL scheme is developed using an optimal configuration of high-power laser diodes matching the selected spectral parameters.