bluuebunny/crossref_metadata_2025 huggingface dataset:
Twin deficit hypothesis and reverse causality: a case study of China
Authors: Banday Umer Jeelanie , Aneja Ranjan
Published: August 2019

This paper analyses the causal relationship between budget deficit and current account deficit for the Chinese economy using time series data over the period of 1985–2016. We initially analyzed the theoretical framework obtained from theKeynesianspending equation and empirically test the hypothesis using autoregressive distributed lag (ARDL) bounds testing and the Zivot and Andrew (ZA) structural break for testing the twin deficits hypothesis. The results of ARDL bound testing approach gives evidence in support of long-run relationship among the variables, validating the Keynesian hypothesis for the Chinese economy. The result of Granger causality test accepts the twin deficit hypothesis. Our results suggest that the negative shock to the budget deficit reduces current account balance and positive shock to the budget deficit increases current account balance. However, higher effect growth shocks and extensive fluctuation in interest rate and exchange rate lead to divergence of the deficits. The interest rate and inflation stability should, therefore, be the target variable for policy makers.
An electrostatic in-line charge-state purification system for multicharged ions in the kiloelectronvolt energy range
Authors: Schury Daniel , Kumar Ajit , Méry Alain , Chesnel Jean-Yves , Lévy Anna , Macé Stéphane , Prigent Christophe , Ramillon Jean-Marc , Rangama Jimmy , Rousseau Patrick , Steydli Sébastien , Trassinelli Martino , Vernhet Dominique , Lamour Emily
Published: August 2019

The performance of a newly built omega type electrostatic analyzer designed to act as an in-line charge-state purification system for ions in the kiloelectronvolt energy range is reported. The analyzer consists of a set of four consecutive electrostatic 140° concentric cylindrical electrodes enclosed by Matsuda electrodes. This setup was recently tested and validated using O5+, Ar9+, and Xe20+ ion beams at an energy of 14 qkeV at the ARIBE facility. A resolving power of 10.5 and a transmission of 100% of the desired charge state are measured allowing a good purification of incoming ion beams with charge states up to 10+ and a fairly good purification for charge states at least up to 20+. In comparison with other in-line solutions such as the Wien filter, our system has the advantage of being purely electrostatic and therefore lacking common drawbacks as, for example, hysteresis.
Design and operation of a scanning electrochemical microscope for imaging with continuous line probes
Authors: Dorfi Anna E. , Kuo Han-wen , Smirnova Vera , Wright John , Esposito Daniel V.
Published: August 2019

This article describes a home-built scanning electrochemical microscope capable of achieving high areal imaging rates through the use of continuous line probes (CLPs) and compressed sensing (CS) image reconstruction. The CLP is a nonlocal probe consisting of a band electrode, where the achievable spatial resolution is set by the thickness of the band and the achievable imaging rate is largely determined by its width. A combination of linear and rotational motors allows for CLP scanning at different angles over areas up to 25 cm2 to generate the raw signal necessary to reconstruct the desired electrochemical image using CS signal analysis algorithms. Herein, we provide detailed descriptions of CLP fabrication, microscope design, and the procedures used to carry out scanning electrochemical microscopy imaging with CLPs. In order to illustrate the basic operating procedures for the microscope, line scans and images measured in the substrate generation-probe-collection mode for flat samples containing platinum disk electrodes are presented. These exemplary measurements illustrate methods for calibrating the positioning system, positioning and cleaning the CLP, and verifying proper positioning/probe sensitivity along its length.
Is radiation damage the limiting factor in high-resolution single particle imaging with X-ray free-electron lasers?
Authors: Östlin C. , Timneanu N. , Caleman C. , Martin A. V.
Published: August 2019

The prospect of single particle imaging with atomic resolution is one of the scientific drivers for the development of X-ray free-electron lasers. The assumption since the beginning has been that damage to the sample caused by intense X-ray pulses is one of the limiting factors for achieving subnanometer X-ray imaging of single particles and that X-ray pulses need to be as short as possible. Based on the molecular dynamics simulations of proteins in X-ray fields of various durations (5 fs, 25 fs, and 50 fs), we show that the noise in the diffracted signal caused by radiation damage is less than what can be expected from other sources, such as sample inhomogeneity and X-ray shot-to-shot variations. These findings show a different aspect of the feasibility of high-resolution single particle imaging using free-electron lasers, where employing X-ray pulses of longer durations could still provide a useful diffraction signal above the noise due to the Coulomb explosion.
The relationship between flux coordinates and equilibrium-based frames of reference in fusion theory
Authors: Kruger S. E. , Greene John M.
Published: August 2019

The properties of two local reference frames based on the magnetic field and the current density are investigated for magnetized plasmas in toroidal geometry with a symmetric angle. The magnetic field-based local frame of reference has been well-studied, for example, by Dewar and colleagues [Phys. Fluids 27, 1723 (1984)]. An analogous frame based on the current density vector is possible because it is also divergence free and perpendicular to the gradient of the poloidal flux. The concept of straightness of a vector is introduced and used to elucidate the Boozer and Hamada coordinate systems. The relationship of these local frames to the more well-known Frenet frame of reference, which specifies a curve in terms of curvature and torsion, is given. As an example of the usefulness of this formal relationship, we briefly review the ideal MHD theory and its use. We also present a new annihilation operator, useful for eliminating shorter time scales than the time scale of interest, for deriving the inner layer equations of Glasser et al. [Phys. Fluids 18, 875 (1975)]. Compared to the original derivation that is based on the local frame of reference in terms of the magnetic field, the new annihilation operator that is based on the local frame of reference in terms of the current density simplifies the derivation.
Tunable ferromagnetic resonance in coupled trilayers with crossed in-plane and perpendicular magnetic anisotropies
Authors: Markó Daniel , Valdés-Bango Fernando , Quirós Carlos , Hierro-Rodríguez Aurelio , Vélez María , Martín José Ignacio , Alameda José María , Schmool David S. , Álvarez-Prado Luis Manuel
Published: August 2019

An original approach to tune the ferromagnetic resonance frequency of a soft magnetic Ni80Fe20 (Permalloy = Py) film with in-plane magnetic anisotropy (IMA) based on the controlled coupling to a hard magnetic NdCox film with perpendicular magnetic anisotropy (PMA) through a nonmagnetic Al spacer is studied. Using the transverse magneto-optical Kerr effect (T-MOKE), alternating gradient magnetometry (AGM), and vector network analyzer ferromagnetic resonance (VNA-FMR) spectroscopy, the influence of both the Co concentration and the Al spacer thickness on the static and dynamic magnetic properties of the coupled IMA/PMA system is investigated. Compared to a single Py film, two striking effects of the coupling between IMA and PMA layers can be observed in their FMR spectra. First, there is a significant increase in the zero-field resonance frequency from 2.0 GHz up to 6.4 GHz, and second, an additional frequency hysteresis occurs at low magnetic fields applied along the hard axis. The maximum frequency difference between the frequency branches for increasing and decreasing magnetic fields is as high as 1 GHz, corresponding to a tunability of about 20% at external fields of typically less than ±70 mT. The origin of the observed features in the FMR spectra is discussed by means of magnetization reversal curves.
Kinetic particle simulations in a global toroidal geometry
Authors: De S. , Singh T. , Kuley A. , Bao J. , Lin Z. , Sun G. Y. , Sharma S. , Sen A.
Published: August 2019

The gyrokinetic toroidal code has been upgraded for global simulations by coupling the core and scrape-off layer regions across the separatrix with field-aligned particle-grid interpolations. A fully kinetic particle pusher for high frequency waves (ion cyclotron frequency and beyond) and a guiding center pusher for low frequency waves have been implemented using cylindrical coordinates in a global toroidal geometry. The two integrators correctly capture the particle orbits and agree well with each other, conserving energy and canonical angular momentum. As a verification and application of this new capability, ion guiding center simulations have been carried out to study ion orbit losses at the edge of the DIII-D tokamak for single null magnetic separatrix discharges. The ion loss conditions are examined as a function of the pitch angle for cases without and with a radial electric field. The simulations show good agreement with past theoretical results and with the experimentally observed feature in which high energy ions flow out along the ion drift orbits and then hit the divertor plates. A measure of the ion direct orbit loss fraction shows that the loss fraction increases with the ion energy for DIII-D in the initial velocity space. Finally, as a further verification of the capability of the new code, self-consistent simulations of zonal flows in the core region of the DIII-D tokamak were carried out. All DIII-D simulations were performed in the absence of turbulence.
A microcantilever mechanical antenna
Authors: Abadal G. , Bramon P. , López-Suárez M. , Agustí J. , Torres F.
Published: August 2019

A mechanical antenna based on the interaction of an oscillating electric field with a permanent electric charge implanted in the free end of a clamped-free beam is proposed as a miniaturized alternative to conventional electromagnetic antennas. A prototype based on a silicon nitride triangular microcantilever has been fabricated, and its response to an oscillating electric field generated by a dipole antenna has been tested. The responsivity, defined as the vibration amplitude per electric field intensity unit, has been experimentally found to be ℜ = 0.29 nm/kV m. A figure of merit (FOM) to evaluate the power conversion efficiency per unit area of the microcantilever antenna has been defined and calculated to be FOM = 0.216% m−2.
Dislocation emission and crack growth in 3D bcc iron crystals under biaxial loading by atomistic simulations
Authors: Uhnáková Alena , Machová Anna , Hora Petr
Published: August 2019

This paper is devoted to the study of the ductile-brittle behavior of a central nanocrack (1¯10)[110] (crack plane/crack front) under biaxial loading via free 3D molecular dynamics (MD) simulations, as well as the comparison of MD results with continuum predictions concerning T-stress. The so called T-stress is a constant stress component acting along the crack plane, which should be considered (together with the stress intensity factor K) in the assessment of brittle-ductile behavior, namely, in the case of the short cracks. Previous 2D atomistic simulations under plane strain conditions indicated that the level of T-stress (controlled by the biaxiality ratio σB/σA from the external loading) affects dislocation emission from the crack and can cause the ductile-brittle transition. The plane strain simulations using the periodic or translational boundary conditions in the bcc lattice have certain limitations: they enable the in-plane dislocation emission (Burgers vector lies in the observation plane), but they do not allow the complete dislocation emission on the all slip systems favored by the shear stress. As presented, our new free 3D atomistic simulations (without periodic or symmetry conditions) enable the activity of the all favored slip systems. Thus, they offer a more realistic insight into the microscopic processes generated by the crack itself in dependence on the T-stress level.
Artificial neural network mixed model for large eddy simulation of compressible isotropic turbulence
Authors: Xie Chenyue , Wang Jianchun , Li Hui , Wan Minping , Chen Shiyi
Published: August 2019

In this work, the subgrid-scale (SGS) stress and the SGS heat flux of compressible isotropic turbulence are modeled by an artificial neural network (ANN) mixed model (ANNMM), which maintains both functional and structural performances. The functional form of the mixed model combining the gradient model and the Smagorinsky’s eddy viscosity model is imposed, and the ANN is used to calculate the model coefficients of the SGS anisotropy stress, SGS energy, and SGS heat flux. It is shown that the ANNMM can reconstruct the SGS terms more accurately than the gradient model in the a priori test. Specifically, the ANNMM almost recovers the average values of the SGS energy flux and SGS energy flux conditioned on the normalized filtered velocity divergence. In an a posteriori analysis, the ANNMM shows advantage over the dynamic Smagorinsky model (DSM) and dynamic mixed model (DMM) in the prediction of the spectra of velocity and temperature, which almost overlap with the filtered direct numerical simulation data, while the DSM and DMM suffer from the problem of the typical tilted spectral distribution. Besides, the ANNMM predicts the probability density functions of SGS energy flux much better than DSM and DMM. ANN with functional model forms can enlighten and deepen our understanding of large eddy simulation modeling.
Pinched P-E hysteresis loops in Ba4Sm2Fe0.5Ti3Nb6.5O30 ceramic with tungsten bronze structure
Authors: Li Cheng , Hong Jiang Sheng , Huang Yu Hui , Ma Xiao , Fu Mao Sen , Li Juan , Liu Xiao Qiang , Wu Yong Jun
Published: August 2019

In the present work, single-phase Ba4Sm2Fe0.5Ti3Nb6.5O30 ceramics with a tetragonal tungsten bronze structure (TTB) were synthesized. Pinched polarization–electric field (P–E) hysteresis loops are observed below the Curie temperature (Tc) in the as-synthesized ceramics. The origin of the loops was thoroughly studied using in situ TEM and XRD. The in situ selected area electron diffraction (SAED) patterns showed that the pinched loops originated from the coexistence of polar commensurate and nonpolar incommensurate superlattice reflections. In situ XRD results revealed increasing tetragonality with rising temperature, implying that the enhancement in octahedral tilting was closely related to the commensurate-incommensurate structural modulation.
Correlation of ion acoustic turbulence with self-organization in a low-temperature plasma
Authors: Georgin Marcel P. , Jorns Benjamin A. , Gallimore Alec D.
Published: August 2019

The correlation between ion acoustic turbulence (IAT) and self-organization is investigated in a low-temperature, current-carrying xenon plasma. Translating probes are used to measure the dispersion and power spectra of relative fluctuations in the ion saturation current in the plume of a hollow cathode discharge. Both ion acoustic waves and a low-frequency, propagating coherent oscillation are detected. Time-resolved measurements reveal that the amplitude of the IAT modes is modulated in time and is highly correlated in space and time with the coherent fluctuations in the ion saturation current and light emission. The phase relationship between the IAT amplitude and these oscillations further suggests that fluctuations in turbulence are causally connected to the periodic, self-organized structure. These results are interpreted in the context of a zero-dimensional model for the electron energy that balances Ohmic heating from the IAT against inelastic losses from ionization. A comparison of the model with the experimental measurements supports the conclusion that this form of self-organization is hydrodynamic in nature but is possibly driven unstable by the presence of kinetic electrostatic turbulence.
A microfluidic device for label-free isolation of tumor cell clusters from unprocessed blood samples
Authors: Kamyabi Nabiollah , Huang Jonathan , Lee Jaewon J. , Bernard Vincent , Semaan Alexander , Stephens Bret , Hurd Mark W. , Vanapalli Siva A. , Maitra Anirban , Guerrero Paola A.
Published: August 2019

Primary cancers disseminate both single circulating tumor cells (CTCs) and CTC “clusters,” the latter of which have been shown to demonstrate greater metastatic propensity and adverse impact on prognosis. Many devices developed to isolate single CTCs also capture CTC clusters, but there is translational potential for a platform specifically designed to isolate CTC clusters. Herein, we introduce our microfluidic device for isolating CTC clusters (“Microfluidic Isolation of CTC Clusters” or MICC), which is equipped with ∼10 000 trap chambers that isolate tumor cell clusters based on their large sizes and dynamic force balance against a pillar obstacle in the trap chamber. Whole blood is injected, followed by a wash step to remove blood cells and a final backflush to release intact clusters for downstream analysis. Using clusters from tumor cell-line and confocal microscopy, we verified the ability of the MICC platform to specifically capture tumor cell clusters in the trap chambers. Our flow rate optimization experiments identified 25 μl/min for blood injection, 100 μl/min as wash flow rate, and 300 μl/min as the release flow rate – indicating that 1 ml of whole blood can be processed in less than an hour. Under these optimal flow conditions, we assessed the MICC platform’s capture and release performance using blood samples spiked with different concentrations of clusters, revealing a capture efficiency of 66%–87% and release efficiency of 76%–90%. The results from our study suggest that the MICC platform has the potential to isolate CTC clusters from cancer patient blood, enabling it for clinical applications in cancer management.
Unraveling the effect of electron-electron interaction on electronic transport in La-doped SrSnO3 films
Authors: Yue Jin , Thoutam Laxman R. , Prakash Abhinav , Wang Tianqi , Jalan Bharat
Published: August 2019

We demonstrate that the electron-electron interaction effect is primarily responsible for an increase in the Hall coefficient in the La-doped SrSnO3 films below 50 K accompanied by an increase in the sheet resistance. The quantitative analysis of the magnetoresistance data yielded a large phase coherence length of electrons exceeding 450 nm at 1.8 K and revealed the electron-electron interaction being accountable for the breaking of electron phase coherency in La-doped SrSnO3 films. These results while providing critical insights into the fundamental transport behavior in doped stannates also indicate the potential applications of stannates in quantum coherent electronic devices owing to their large phase coherence length.
Influence of austenite ferromagnetism on the elastocaloric effect in a Ni44.9Co4.9Mn36.9In13.3 metamagnetic shape memory alloy
Authors: Li Zhenzhuang , Li Zongbin , Li Dong , Yang Jiajing , Yang Bo , Wang Dunhui , Hou Long , Li Xi , Zhang Yudong , Esling Claude , Zhao Xiang , Zuo Liang
Published: August 2019

We demonstrate the temperature dependent elastocaloric effect in a Ni44.9Co4.9Mn36.9In13.3 polycrystalline alloy with a strong ⟨001⟩A preferred orientation. It is found that the adiabatic temperature changes induced by the compressive stress increase with the increase in testing temperature. The giant adiabatic temperature change up to 14.7 K is achieved on loading at 390 K, which is much higher than that around room temperature. Such a temperature enhanced effect is attributed to the reduced magnetic contribution to the transformation entropy through narrowing the temperature interval between magnetic transition and martensitic transformation controlled by the mechanical stress.
Viscosity and viscoelasticity of liquid nanoparticles with polymeric matrix
Authors: Malkin A. Ya. , Polyakova M. Yu. , Andrianov A. V. , Meshkov I. V. , Muzafarov A. M.
Published: August 2019

The subject of this study is polymethylsilsesquioxane nanoparticles of different sizes and molecular weights (MW). Unlike numerous solid nanoparticles, these objects form liquids. They could be considered as an intermediate structure between macromolecules and colloidal particles. Their structure can be described as a solid core surrounded by a soft cover. The flow happens by relaxation mechanism and the high viscosity is not due to entanglements (as it takes place in linear polymers) but due to interparticle friction. The study of these liquids revealed several rather special rheological phenomena. The characteristic size of these nanoparticles is proportional to their MW. It means that the looseness of these nano-objects increases along with their MW. The dependence of viscosity on MW is unusually strong in comparison to all known cases and can be described by a power law with an exponent of the order of 8.5. In opposite to the known Cox-Merz rule having the universal value for flexible polymers, there is no correlation between the dynamic viscosity in oscillations and the Newtonian viscosity in steady flows. These evidences point to deep differences in the mechanisms of flow and viscoelasticity between nanoliquids and polymer melts. Temperature dependence of viscosity is described by the equation typical for amorphous liquids and at some critical temperature, the transition to a glassy state (or gelation) of these nanoliquids takes place. The transition temperature depends on MW and the viscosity is determined by remoteness from the transition temperature. The flow of nanoliquids is Newtonian though they demonstrate viscoelastic behavior with a rather wide relaxation spectrum. In general, the rheology of the nanoparticles under study is close to the behavior of the so-called Boger liquids without any nonlinear phenomena. Interpretation of the rheological behavior of nanoparticles/polymer melt mixtures is based on the concept of dualism of nanoparticles which are simultaneously liquids and colloidal objects. Depending on the composition, mixtures can be homogeneous or two-phase systems while phase separation at a high shear rate can be a deformation-induced phenomenon.
Explicit expressions for Rortex tensor and velocity gradient tensor decomposition
Authors: Gao Yisheng , Yu Yifei , Liu Jianming , Liu Chaoqun
Published: August 2019

The introduction of Rortex provides a new perspective to investigate the local properties of vortical structures in transitional and turbulent flows, as Rortex offers a new and systematic description of the local fluid rotation, including scalar, vector and tensor forms. Unfortunately, the previous definition of Rortex is not straightforward, which requires the explicit calculation of somewhat cumbersome coordinate rotation. In this letter, a new explicit tensor form of Rortex and the relevant explicit velocity gradient tensor decomposition are presented, based on an explicit formula of the Rortex vector. The explicit tensor form represents the real local rotational part of the velocity gradient tensor in the original coordinate system. The explicit calculation of coordinate rotations can be totally avoided, which indicates an important improvement of Rortex based velocity gradient tensor decomposition.
Prediction and measurement of the fastest-growing mode in two-liquid systems
Authors: Patrascu Claudiu , Balan Corneliu
Published: August 2019

The paper is concerned with the capillary instability of a liquid thread surrounded by another immiscible liquid. We study the occurrence of the dominant mode of perturbation for different combinations of Newtonian and viscoelastic fluids. When a viscoelastic fluid is present, in the limit of small deformations, the dispersion relation is obtained via a Maxwell type approximation of the viscosity curve which can be directly incorporated into an existing model of thread instability. Measurements of the fastest-growing mode are then performed and compared with theoretical predictions. A satisfactory agreement between the theory and experiment is found in terms of the wavenumber of the fastest-growing mode.
Improving the management of Australia’s biodiversity through better synergy between private and public protected areas – a response to Australia’s biodiversity loss
Authors: Heise-Pavlov Sigrid
Published: August 2019

Australia has one of the highest rates of biodiversity loss globally. Both a lack of long-term monitoring and inefficient management have been identified as major contributing factors. Reviewing national and international reports, perspectives and scientific studies on Australia’s biodiversity management, I propose five steps to promote more effective management and monitoring of protected biodiversity assets by utilising available resources more efficiently. These steps involve: (1) better promotion of existing legislative instruments to protect biodiversity on private land; (2) creating strategic buffer zones around Australia’s World Heritage Areas (WHAs) – such buffer zones would provide opportunities to reduce threats to the biological assets of WHAs that emanate from adjacent areas; (3) better engagement with stakeholders of the buffer zones in managing WHAs through their participation in evidence-based monitoring and early-threat detection (e.g. as ‘Buffer-based Heritage Watch’); (4) targeted and coordinated restoration of native habitats adjacent to WHAs that are supported by effective carbon sequestration schemes; and (5) periodic integration of private protected areas within buffer zones into adjacent WHAs in accordance with the guidelines for extensions of WHAs by the World Heritage Committee. I demonstrate and justify the proposed steps using a spatial analysis of protected areas in Far North Queensland, but the proposed steps have relevance to protected areas in other Australian jurisdictions. The proposed steps would make current efforts of biodiversity protection and monitoring more efficient and would thus contribute to Australia’s response to its current loss of biodiversity.
Role of soluble endoglin in BMP9 signaling
Authors: Lawera Aleksandra , Tong Zhen , Thorikay Midory , Redgrave Rachael E. , Cai Jie , van Dinther Maarten , Morrell Nicholas W. , Afink Gijs B. , Charnock-Jones D. Stephen , Arthur Helen M. , ten Dijke Peter , Li Wei
Published: August 2019

Endoglin (ENG) is a coreceptor of the transforming growth factor-β (TGFβ) family signaling complex, which is highly expressed on endothelial cells and plays a key role in angiogenesis. Its extracellular domain can be cleaved and released into the circulation as soluble ENG (sENG). High circulating levels of sENG contribute to the pathogenesis of preeclampsia (PE). Circulating bone morphogenetic protein 9 (BMP9), a vascular quiescence and endothelial-protective factor, binds sENG with high affinity, but how sENG participates in BMP9 signaling complexes is not fully resolved. sENG was thought to be a ligand trap for BMP9, preventing type II receptor binding and BMP9 signaling. Here we show that, despite cell-surface ENG being a dimer linked by disulfide bonds, sENG purified from human placenta and plasma from PE patients is primarily in a monomeric form. Incubating monomeric sENG with the circulating form of BMP9 (prodomain-bound form) in solution leads to the release of the prodomain and formation of a sENG:BMP9 complex. Furthermore, we demonstrate that binding of sENG to BMP9 does not inhibit BMP9 signaling. Indeed, the sENG:BMP9 complex signals with comparable potency and specificity to BMP9 on human primary endothelial cells. The full signaling activity of the sENG:BMP9 complex required transmembrane ENG. This study confirms that rather than being an inhibitory ligand trap, increased circulating sENG might preferentially direct BMP9 signaling via cell-surface ENG at the endothelium. This is important for understanding the role of sENG in the pathobiology of PE and other cardiovascular diseases.
Global change effects on plant communities are magnified by time and the number of global change factors imposed
Authors: Komatsu Kimberly J. , Avolio Meghan L. , Lemoine Nathan P. , Isbell Forest , Grman Emily , Houseman Gregory R. , Koerner Sally E. , Johnson David S. , Wilcox Kevin R. , Alatalo Juha M. , Anderson John P. , Aerts Rien , Baer Sara G. , Baldwin Andrew H. , Bates Jonathan , Beierkuhnlein Carl , Belote R. Travis , Blair John , Bloor Juliette M. G. , Bohlen Patrick J. , Bork Edward W. , Boughton Elizabeth H. , Bowman William D. , Britton Andrea J. , Cahill James F. , Chaneton Enrique , Chiariello Nona R. , Cheng Jimin , Collins Scott L. , Cornelissen J. Hans C. , Du Guozhen , Eskelinen Anu , Firn Jennifer , Foster Bryan , Gough Laura , Gross Katherine , Hallett Lauren M. , Han Xingguo , Harmens Harry , Hovenden Mark J. , Jagerbrand Annika , Jentsch Anke , Kern Christel , Klanderud Kari , Knapp Alan K. , Kreyling Juergen , Li Wei , Luo Yiqi , McCulley Rebecca L. , McLaren Jennie R. , Megonigal J. Patrick , Morgan John W. , Onipchenko Vladimir , Pennings Steven C. , Prevéy Janet S. , Price Jodi N. , Reich Peter B. , Robinson Clare H. , Russell F. Leland , Sala Osvaldo E. , Seabloom Eric W. , Smith Melinda D. , Soudzilovskaia Nadejda A. , Souza Lara , Suding Katherine , Suttle K. Blake , Svejcar Tony , Tilman David , Tognetti Pedro , Turkington Roy , White Shannon , Xu Zhuwen , Yahdjian Laura , Yu Qiang , Zhang Pengfei , Zhang Yunhai
Published: August 2019

Significance

Accurate prediction of community responses to global change drivers (GCDs) is critical given the effects of biodiversity on ecosystem services. There is consensus that human activities are driving species extinctions at the global scale, but debate remains over whether GCDs are systematically altering local communities worldwide. Across 105 experiments that included over 400 experimental manipulations, we found evidence for a lagged response of herbaceous plant communities to GCDs caused by shifts in the identities and relative abundances of species, often without a corresponding difference in species richness. These results provide evidence that community responses are pervasive across a wide variety of GCDs on long-term temporal scales and that these responses increase in strength when multiple GCDs are simultaneously imposed.
A conserved but plant-specific CDK-mediated regulation of DNA replication protein A2 in the precise control of stomatal terminal division
Authors: Yang Kezhen , Zhu Lingling , Wang Hongzhe , Jiang Min , Xiao Chunwang , Hu Xiangyang , Vanneste Steffen , Dong Juan , Le Jie
Published: August 2019

Significance

The
Arabidopsis
R2R3-MYB transcription factor FOUR LIPS (FLP) is the first identified key transcription factor regulating stomatal development. By screening and analyzing a genetic suppressor of
flp
stomatal defects, we found that
FSP1/RPA2a
, which encodes a core subunit of Replication Protein A (RPA) complexes, acts downstream of B1-type Cyclin-Dependent Kinases (CDKB1s). This ensures that terminal division during stomatal development will produce a pair of kidney-shaped guard cells to compose a functional stomatal complex. We demonstrate that the CDK-mediated phosphorylation at the N terminus of RPA2a is essential for the RPA functions in cell cycle control and response to DNA damage. We provide direct evidence for the existence of an evolutionarily conserved, but plant-specific, RPA regulatory pathway in plants.
Tissue-specific geometry and chemistry of modern and fossilized melanosomes reveal internal anatomy of extinct vertebrates
Authors: Rossi Valentina , McNamara Maria E. , Webb Sam M. , Ito Shosuke , Wakamatsu Kazumasa
Published: August 2019

Significance

Recent reports of nonintegumentary melanosomes in fossils hint at functions for melanin beyond color production, but the biology and evolution of internal melanins are poorly understood. Our results show that internal melanosomes are widespread in diverse fossil and modern vertebrates and have tissue-specific geometries and metal chemistries. Tissue-specific chemical signatures can persist in fossils despite some diagenetic overprint, allowing the reconstruction of internal soft-tissue anatomy in fossil vertebrates, and suggest that links between melanin and metal regulation have deep evolutionary origins in vertebrates.
Biomineralization by particle attachment in early animals
Authors: Gilbert Pupa U. P. A. , Porter Susannah M. , Sun Chang-Yu , Xiao Shuhai , Gibson Brandt M. , Shenkar Noa , Knoll Andrew H.
Published: August 2019

Significance

The mechanisms by which organisms form mineralized skeletons have been a major research focus for the last 50 y and remain so today. Among the most surprising discoveries is the recent observation that different animals use the same mechanisms, and precisely the same amorphous precursors, to form biomineralized structures as diverse as coral skeletons, molluscan shells, and sea urchin spines. In living animals, skeletal biomineralization from amorphous precursors correlates with a distinctive nanoparticulate texture that can be preserved in fossils, enabling us to probe mechanisms of skeletal formation in early animals. We document nanoparticulate texture in some of the oldest known carbonate skeletons, which strongly suggests that skeletons formed from amorphous precursors throughout the recorded history of animals.
On the evolution and physiology of cable bacteria
Authors: Kjeldsen Kasper U. , Schreiber Lars , Thorup Casper A. , Boesen Thomas , Bjerg Jesper T. , Yang Tingting , Dueholm Morten S. , Larsen Steffen , Risgaard-Petersen Nils , Nierychlo Marta , Schmid Markus , Bøggild Andreas , van de Vossenberg Jack , Geelhoed Jeanine S. , Meysman Filip J. R. , Wagner Michael , Nielsen Per H. , Nielsen Lars Peter , Schramm Andreas
Published: August 2019

Cable bacteria of the family Desulfobulbaceae form centimeter-long filaments comprising thousands of cells. They occur worldwide in the surface of aquatic sediments, where they connect sulfide oxidation with oxygen or nitrate reduction via long-distance electron transport. In the absence of pure cultures, we used single-filament genomics and metagenomics to retrieve draft genomes of 3 marine
Candidatus
Electrothrix and 1 freshwater
Ca.
Electronema species. These genomes contain >50% unknown genes but still share their core genomic makeup with sulfate-reducing and sulfur-disproportionating Desulfobulbaceae, with few core genes lost and 212 unique genes (from 197 gene families) conserved among cable bacteria. Last common ancestor analysis indicates gene divergence and lateral gene transfer as equally important origins of these unique genes. With support from metaproteomics of a
Ca.
Electronema enrichment, the genomes suggest that cable bacteria oxidize sulfide by reversing the canonical sulfate reduction pathway and fix CO
2
using the Wood–Ljungdahl pathway. Cable bacteria show limited organotrophic potential, may assimilate smaller organic acids and alcohols, fix N
2
, and synthesize polyphosphates and polyglucose as storage compounds; several of these traits were confirmed by cell-level experimental analyses. We propose a model for electron flow from sulfide to oxygen that involves periplasmic cytochromes, yet-unidentified conductive periplasmic fibers, and periplasmic oxygen reduction. This model proposes that an active cable bacterium gains energy in the anodic, sulfide-oxidizing cells, whereas cells in the oxic zone flare off electrons through intense cathodic oxygen respiration without energy conservation; this peculiar form of multicellularity seems unparalleled in the microbial world.
Proglacial freshwaters are significant and previously unrecognized sinks of atmospheric CO
2
Authors: St. Pierre Kyra A. , St. Louis Vincent L. , Schiff Sherry L. , Lehnherr Igor , Dainard Paul G. , Gardner Alex S. , Aukes Pieter J. K. , Sharp Martin J.
Published: August 2019

Significance

Glacier melt is one of the most dramatic consequences of climate change in high-latitude and high-altitude environments. As meltwaters move across poorly consolidated landscapes, they transport vast quantities of highly reactive comminuted sediments prone to chemical weathering reactions that may consume atmospheric CO
2
. Using a whole watershed approach in the Canadian High Arctic, combined with additional dissolved CO
2
measurements in glacial rivers in Greenland and the Canadian Rockies, we show that certain glacier-fed freshwater ecosystems are significant and previously unrecognized annual CO
2
sinks due to chemical weathering. As many of the world’s rivers originate from glacial headwaters, we highlight the potential importance of this process for contemporary regional carbon budgets in rapidly changing high-latitude and high-altitude watersheds.
Origins of the concepts cause, cost, and goal in prereaching infants
Authors: Liu Shari , Brooks Neon B. , Spelke Elizabeth S.
Published: August 2019

We investigated the origins and interrelations of causal knowledge and knowledge of agency in 3-month-old infants, who cannot yet effect changes in the world by reaching for, grasping, and picking up objects. Across 5 experiments,
n
= 152 prereaching infants viewed object-directed reaches that varied in efficiency (following the shortest physically possible path vs. a longer path), goal (lifting an object vs. causing a change in its state), and causal structure (action on contact vs. action at a distance and after a delay). Prereaching infants showed no strong looking preference between a person’s efficient and inefficient reaches when the person grasped and displaced an object. When the person reached for and caused a change in the state of the object on contact, however, infants looked longer when this action was inefficient than when it was efficient. Three-month-old infants also showed a key signature of adults’ and older infants’ causal inferences: This looking preference was abolished if a short spatial and temporal gap separated the action from its effect. The basic intuition that people are causal agents, who navigate around physical constraints to change the state of the world, may be one important foundation for infants’ ability to plan their own actions and learn from the acts of others.
Horizontal gene transfer overrides mutation in
Escherichia coli
colonizing the mammalian gut
Authors: Frazão Nelson , Sousa Ana , Lässig Michael , Gordo Isabel
Published: August 2019

Bacteria evolve by mutation accumulation in laboratory experiments, but tempo and mode of evolution in natural environments are largely unknown. Here, we study the ubiquitous natural process of host colonization by commensal bacteria. We show, by experimental evolution of
Escherichia coli
in the mouse intestine, that the ecology of the gut controls the pace and mode of evolution of a new invading bacterial strain. If a resident
E. coli
strain is present in the gut, the invading strain evolves by rapid horizontal gene transfer (HGT), which precedes and outweighs evolution by accumulation of mutations. HGT is driven by 2 bacteriophages carried by the resident strain, which cause an epidemic phage infection of the invader. These dynamics are followed by subsequent evolution by clonal interference of genetically diverse lineages of phage-carrying (lysogenic) bacteria. We show that the genes uptaken by HGT enhance the metabolism of specific gut carbon sources and provide a fitness advantage to lysogenic invader lineages. A minimal dynamical model explains the temporal pattern of phage epidemics and the complex evolutionary outcome of phage-mediated selection. We conclude that phage-driven HGT is a key eco-evolutionary driving force of gut colonization—it accelerates evolution and promotes genetic diversity of commensal bacteria.
A unique variant of lymphocytic choriomeningitis virus that induces pheromone binding protein MUP: Critical role for CTL
Authors: Ware Brian C. , Sullivan Brian M. , LaVergne Stephanie , Marro Brett S. , Egashira Toru , Campbell Kevin P. , Elder John , Oldstone Michael B. A.
Published: August 2019

Significance

Pheromones play essential roles in host communications and sexual attraction, and thus regulate adaptive behavior. Here we present the discovery and characterization of the first known virus, a variant of lymphocytic choriomeningitis virus, that selectively induces pheromone binding protein mouse urinary protein. Furthermore, we found that cytotoxic T lymphocytes play a critical role in mouse urinary protein generation.
Large-scale identification of pathogen essential genes during coinfection with sympatric and allopatric microbes
Authors: Lewin Gina R. , Stacy Apollo , Michie Kelly L. , Lamont Richard J. , Whiteley Marvin
Published: August 2019

Recent evidence suggests that the genes an organism needs to survive in an environment drastically differ when alone or in a community. However, it is not known if there are universal functions that enable microbes to persist in a community and if there are functions specific to interactions between microbes native to the same (sympatric) or different (allopatric) environments. Here, we ask how the essential functions of the oral pathogen
Aggregatibacter actinomycetemcomitans
change during pairwise coinfection in a murine abscess with each of 15 microbes commonly found in the oral cavity and 10 microbes that are not.
A. actinomycetemcomitans
was more abundant when coinfected with allopatric than with sympatric microbes, and this increased fitness correlated with expanded metabolic capacity of the coinfecting microbes. Using transposon sequencing, we discovered that 33% of the
A. actinomycetemcomitans
genome is required for coinfection fitness. Fifty-nine “core” genes were required across all coinfections and included genes necessary for aerobic respiration. The core genes were also all required in monoinfection, indicating the essentiality of these genes cannot be alleviated by a coinfecting microbe. Furthermore, coinfection with some microbes, predominately sympatric species, induced the requirement for over 100 new community-dependent essential genes. In contrast, in other coinfections, predominately with nonoral species,
A. actinomycetemcomitans
required 50 fewer genes than in monoinfection, demonstrating that some allopatric microbes can drastically alleviate gene essentialities. These results expand our understanding of how diverse microbes alter growth and gene essentiality within polymicrobial infections.
Abiotic methane synthesis and serpentinization in olivine-hosted fluid inclusions
Authors: Klein Frieder , Grozeva Niya G. , Seewald Jeffrey S.
Published: August 2019

Significance

Our findings highlight the ubiquitous occurrence of methane (CH
4
)-rich fluid inclusions in olivine-bearing rocks that, collectively, may constitute one of the largest reservoirs of abiotic CH
4
on Earth. Because serpentinization in olivine-hosted fluid inclusions takes place in isolation from the surrounding rock, hydrogen (H
2
) and CH
4
can form in any rock type containing olivine that hosts aqueous fluid inclusions, including those that do not undergo serpentinization on a macroscopic scale. Serpentinization and associated CH
4
formation within olivine-hosted fluid inclusions has likely supplied microbial ecosystems with abiotic CH
4
throughout most of Earth’s history and may be a source of H
2
and CH
4
on other planetary bodies in our solar system, even those where liquid water is no longer present.
“Immigration, that’s what everyone’s thinking about …”
Authors: Guerra Simona
Published: August 2019

This article examines the 2016 British EU referendum and the domestic debates through citizens’ voices in the media, specifically on the emotions and narratives, on The Guardian, The Daily Telegraph and The Daily Express, the week before the referendum. British citizens felt, in their words, “bullied because of [their] political correctness” and pointed their anger and dissatisfaction against the EU (and Merkel’s) “obsession for open borders”. The analysis underlines that these emotions and narratives, combining immigration and sovereignty, have remained embedded in the post-Brexit days, and go back not just to Billig’s banal nationalism (1995), but show that voting Leave represented respect towards true British values, the “core country” as conceptualised by Taggart (2000). Powellism (Hampshire 2018) and Wright’s “encroanchment” of Englishness (2017), and the analysis on the immigration narrative explain how anti-immigration and sovereignty discourse is persisting and is influencing the social and political relation of Britain with Europe.
“Girl-on-girl culture”
Authors: Bailey Aimee
Published: August 2019

This article investigates the construction of sex advice for queer women as it features on the world’s most popular lesbian website, Autostraddle. Based in the United States, the website is a “progressively feminist” online community for lesbian, bisexual and other queer women. Using multimodal critical discourse analysis and corpus linguistics, this article explores how representations of sexual and gender identity facilitate the construction of homonormativity on the website. It argues that these representations involve a tension between exclusivity and inclusivity. On the one hand, Autostraddle wants to construct an exclusive markedly lesbian subjectivity and a subcultural model of lesbian sex, which is lacking in mainstream culture. On the other hand, it aims to be inclusive of transgender and bisexual women, and to deconstruct the idea of sexual homogeneity. Findings show that Autostraddle discursively negotiates these competing goals to construct a distinctly “queer female” normativity centred on young cisgender feminine lesbians.
Massive corpora and models of cross‑cultural communication styles in Cognitive Linguitics
Authors: Pavlović Vladan
Published: August 2019

The paper addresses a pair of construction variants: the N1 V for N2
to-infinitive construction and its version without for, in the cases when both are possible with
the same main verb (I need for him leave / I need you to stop). It aims
to point to the importance of the use of massive e-corpora in gaining better insight into the given construction pair. It also
aims to test the hypothesis that the obtained quantitative data from such corpora can at least partially be accounted for by the
interplay of: (1) the differences in the semantics of the two construction variants (based on combining relevant
cognitive-linguistic insights), (2) the differences in the lexical semantics of the main verbs, and (3) extra-linguistic factors
dealt with by models of cross-cultural communication styles. The paper thus argues for a tighter integration of
cognitive-linguistic insights and a social-interactional perspective on language phenomena.
The length of preceding context influences metonymy processing
Authors: Chen Xianglan , Li Fang , Duan Yachao , Duan Yahui
Published: August 2019

Earlier studies have shown that conceptually supportive context is an important factor in the comprehension of metaphors (Inhoff, Lima, & Carroll, 1984;Ortony, Schallert, Reynolds, & Antos, 1978). However, little empirical evidence has been found so far regarding contextual effects on metonymy processing (Lowder & Gordon, 2013). Implementing an eye-tracking experiment with Chinese materials, this present paper investigated whether and how preceding contextual information affects the processing of metonymy. The results show that for unfamiliar metonymies, it takes readers longer time to interpret unfamiliar metonymies than to literally interpret them given a shorter context. However, the processing disparity between metonymic comprehension and literal comprehension disappears when longer supportive information is available in the preceding context. These results are analogous to those found for metaphors and familiar metonymies, supporting the parallel model of language processing. In addition, our results suggest that the presence of supportive preceding context facilitates the processing of unfamiliar metonymies more than it does to the literal controls.