bluuebunny/crossref_metadata_2025 huggingface dataset:
Retrosigmoid Approach: A Simple and Safe Way to Resect Intrinsic Pontomedullary Lesions
Authors: González-Darder José M. , Capilla-Guasch Pau , Real-Peña Luis
Published: April 2019

Objectives The main objective of this article is to describe a simple and safe protocol for the microsurgical management of ventrally located intrinsic pontomedullary lesions based on the retrosigmoid approach, cortectomy performed utilizing safe entry zones of the pons and medulla, and a delicate microsurgical resection. The intraoperative protocol includes redundant procedures that provide security in decision-making during surgery.

Design A prospective series of 11 cases is presented. All patients were studied following the same clinical and imaging workup. A regular retrosigmoid craniotomy surgical approach was utilized. The peritrigeminal area in the pons and the olivary area in the medulla were considered as the safe entry zones. Neuronavigation of the white fiber tracts and electrophysiological monitoring were used as intraoperative aids to locate the lesions, the safe entry zones, and the placement of the cortectomy.

Results Six lesions were pontine, two medullary, and the remaining six pontomedullary. Eight lesions were cavernomas, while the remaining three tumors. Overall, we obtained a postoperative functional improvement in the affected cranial nerves in 90.1% of the patients and a total or partial recovery of long ascending or descending pathway symptoms in 72.3% of the patients. All the patients were satisfied with the procedure and the results.

Conclusions Radical resection of ventral intrinsic pontomedullary lesions displays a high degree of intraoperative reliability, and a good clinical result is possible using simple surgical procedures. The anatomical references are the first element in the decision-making process during surgery.
A geometric model of ion orbit loss under the influence of a radial electric field
Authors: Brzozowski Robert W. , Jenko Frank , Bilato Roberto , Cavedon Marco ,   the ASDEX Upgrade Team
Published: April 2019

A geometric approach is used to find the threshold energies for ion orbit loss in experimental tokamak geometry, like that of ASDEX Upgrade. The effects of any pre-existing radial electric field are maintained as they nontrivially affect the calculations. The associated velocity-space loss hole is investigated using equilibria and profiles from ASDEX Upgrade discharges 30628, in the L-mode just before the L-H transition and in the resultant H-mode, and 31533, an H-mode shot with a comparably high ion temperature. We use a novel technique to calculate the shift of the passing-trapped boundary and see that the experimental radial electric field allows for upwardly bounded regions (UBRs) of the loss hole, which are now studied in detail. We further develop a new loss-hole-shape sensitive method to treat the steady-state ion orbit losses by considering relaxation processes along the border of the loss cone. Typical characteristic times of the steady-state losses in the pedestal region of an H-mode are found to be between 1 and 10 ms. The UBRs significantly enhance the steady-state losses in two ways: these velocity-space loss regions reach further into thermally accessible regions and the extensions are shaped such that they have the ability to refill under both diffusive and slowing down relaxation processes.
Shear horizontal wave propagation along a periodic metal grating surface of a magneto-electro-elastic substrate
Authors: Pang Yu , Xu Chunyu , Ge Tai , Feng Wenjie
Published: April 2019

This paper analyzes shear horizontal (SH) waves propagating in thin metal strips deposited periodically onto the surface of a magneto-electro-elastic (MEE) substrate. The MEE substrate is assumed to be a transversely isotropic crystal with 6 mm symmetry or a hexagonal (6 mm) crystal. A field analysis method, which is based on the Bloch–Floquet theory and the coupled equations of wave motion, is employed to derive the dispersion equations and wave mode shapes. Numerical examples are presented for an MEE composite (PZT4/CoFe2O4) and an aluminum (Al) strip. For comparison, different constituent ratios of PZT4/CoFe2O4 are considered. The effect of the ratios of strip height and width to grating periodicity on frequencies, phase velocities, as well as wave mode shapes is discussed in detail. The results show that there is a bandgap at the resonance condition when the grating periodicity matches the wavelength of the SH surface wave. This metal grating surface can trap SH surface waves by slowing the SH waves. The wave mode shapes indicate that the SH surface waves are trapped mainly on these metal strips. As the ratio of strip height to grating periodicity increases, the trapping effect is more pronounced and the gap becomes wider. The ratio of strip width to grating periodicity significantly affects the behavior of SH surface waves. The present results are relevant in the application of MEE surface acoustic wave resonators.
Low-temperature coexistence of memory and threshold switchings in Pt/TiOx/Pt crossbar arrays
Authors: Alagoz H. S. , Chow K. H. , Jung J.
Published: April 2019

In this work, we studied the low-temperature electrical switching characteristics of a Pt/TiOx/Pt crossbar array. The device exhibits threshold switching behavior upon cooling from 100 K to 65 K and an interesting combination of threshold and memory switchings at temperatures between 65 K and 25 K. The thermally activated changes of these switching characteristics are discussed.
Contact resistance at graphene/MoS2 lateral heterostructures
Authors: Houssa M. , Iordanidou K. , Dabral A. , Lu A. , Meng R. , Pourtois G. , Afanas'ev V. V. , Stesmans A.
Published: April 2019

The contact resistance at two-dimensional graphene/MoS2 lateral heterojunctions is theoretically studied, using first-principles simulations based on density functional theory and the nonequilibrium Green's function method. The computed contact resistance lies in the range of 102 to 104 Ω μm, depending on the contact edge symmetry (armchair or zigzag) and termination (Mo and/or S terminated). This large variation in the contact resistance arises from the variation in the interface barrier height, which is sensitive to the presence of polar C-Mo bonds or sulfur dangling bonds at the interface. These results highlight that the control of the edge symmetry and/or edge termination is crucial to achieve a low contact resistance (in the range of a few hundred ohms micrometer) at graphene/MoS2 lateral heterojunctions for 2D material-based field-effect devices.
Thermal fluctuation noise in Mo/Au superconducting transition-edge sensor microcalorimeters
Authors: Wakeham N. A. , Adams J. S. , Bandler S. R. , Beaumont S. , Chervenak J. A. , Datesman A. M. , Eckart M. E. , Finkbeiner F. M. , Hummatov R. , Kelley R. L. , Kilbourne C. A. , Miniussi A. R. , Porter F. S. , Sadleir J. E. , Sakai K. , Smith S. J. , Wassell E. J.
Published: April 2019

In many superconducting transition-edge sensor (TES) microcalorimeters, the measured electrical noise exceeds theoretical estimates based on a thermal model of a single body thermally connected to a heat bath. Here, we report on noise and complex impedance measurements of a range of designs of TESs made with a Mo/Au bilayer. We have fitted the measured data using a two-body model, where the x-ray absorber and the TES are connected by an internal thermal conductance Gae. We find that the so-called excess noise measured in these devices is consistent with the noise generated from the internal thermal fluctuations between the x-ray absorber and the TES. Our fitted parameters are consistent with the origin of Gae being from the finite thermal conductance of the TES itself. These results suggest that even in these relatively low resistance Mo/Au TESs, the internal thermal conductance of the TES may add significant additional noise and could account for all the measured excess noise. Furthermore, we find that around regions of the superconducting transition with rapidly changing derivative of resistance with respect to temperature, an additional noise mechanism may dominate. These observations may lead to a greater understanding of TES devices and allow the design of TES microcalorimeters with improved performance.
Micrometer-sized titanium carbide with properties comparable to those of nanocrystalline counterparts
Authors: Wang Zhiwei , Kou Zili , Zhang Yuanfen , Yang Ming , Gong Hongxia , Liang Hao , Huo Ruizhi , Guan Shixue , Yin Xiaoshuang , He Duanwei
Published: April 2019

The influence of sintering pressure on the mechanical properties of bulk titanium carbide (TiC) fabricated through work hardening at high pressure and high temperature is investigated systematically. A series of pure polycrystalline TiC samples are prepared by sintering micrometer-sized TiC powders at a pressure of 9.0–14.0 GPa and a temperature of 1500 °C. These samples are then characterized by various techniques for determining their residual stress, grain size, density, microstructural defects, hardness, and fracture toughness. The results demonstrate that the Vickers hardness HV and the fracture toughness KIC depend strongly on the sintering pressure. It is found that the mechanical properties of the sintered samples improve with increasing sintering pressure. The relative density increases with increasing sintering pressure, reaching near full density at 14.0 GPa. The hardness and fracture toughness of the sample sintered at 1500 °C at 14.0 GPa pressure are 31.2 GPa and 4.2 MPa m1/2, respectively. The high-pressure and high-temperature environment causes severe plastic deformation of the grains, as well as a high density of dislocations, resulting in a dislocation pileup. The latter, together with the production of defects such as sub-boundaries and stacking faults, provides strengthening and stabilizing effects and improves the material hardness.
Binding of atoms in Müller theory
Authors: Goto Yukimi
Published: April 2019

We give a necessary and sufficient condition for the existence of molecules in Müller theory. Furthermore, we show that if a system is stable in the Born-Oppenheimer approximation, then the bound on the positive excess charge Z − N ≤ cZ1−ε follows.
The theory and application of eulerlets
Authors: Chadwick E. , Christian J. M. , Kapoulas A. , Chalasani K.
Published: April 2019

Consider a fixed body in a uniform flow field in the limit as the Reynolds number approaches infinity and the flow field remains steady. Instead of using standard techniques and theory for describing the problem, a new method is employed based upon the concept of matching two different Green’s integral representations over a common boundary, one given by approximations valid in the near-field and the other by approximations in the far-field. Further novelty arises from the choice of a near-field, that is, the Euler flow matched to an Oseen flow far-field. This entails introducing and defining eulerlets that are Green’s functions of the Euler equation. One important consequence of the model is the presence of a new Euler wake velocity not captured in standard models. This has a constant unchanging downstream profile and arises from the matching to the far-field Oseen wake velocity. It is then shown how this representation reduces to classical inviscid ideal flow aerodynamics when applied to flow past aerofoils and wings. It is also shown how it reduces to slender body flow theory. Finally, the formulation is tested on uniform flow past a circular cylinder for mean-steady subcritical laminar flow and turbulent flow. The inviscid impermeability boundary condition is used, the drag coefficient is specified, and a constant distribution of drag eulerlets is modeled. The forward flow separation and pressure drop in the wake are captured and compare favorably with experiment. The future expectation is the modeling of multiple general shaped bodies.
Improved electrocaloric properties in La doped (Bi0.5Na0.5)0.92Ba0.08TiO3 lead-free ceramics
Authors: Mendez-González Y. , Peláiz-Barranco A. , Guerra J. D. S.
Published: April 2019

The electrocaloric effect of (Bi0.5Na0.5)0.92Ba0.08–3x/2LaxTiO3 lead free ceramics with x = 0, 0.01, 0.02, and 0.03 was investigated by an indirect method. A high electrocaloric response was achieved in a (Bi0.5Na0.5)0.92Ba0.05La0.02TiO3 composition at 70 °C with an adiabatic temperature change ΔT around 2.11 °C and an electrocaloric strength ΔT/ΔE of 0.42 K mm kV−1, under a relatively low electric field of 50 kV/cm. For this material, a maximum entropy change ΔS of 2.46 J kg−1 K−1 was also obtained under the same conditions. These results are comparable with the best values reported in lead-free materials, suggesting this system as a potential candidate for practical electrocaloric device applications.
Customizable two-species kinetic equilibria for nonuniform low-beta plasmas
Authors: Vogman G. V. , Hammer J. H. , Farmer W. A.
Published: April 2019

Two methods are developed for constructing self-consistent two-species kinetic equilibria for low-beta electrostatic plasmas, in which the magnetic field is uniform and fixed in time. The first method uses Taylor series approximations to construct distribution functions that can be specified analytically. The second method relies on numerically solving a nonlinear ordinary differential equation and produces exact—to numerical precision—equilibria. In both methods, the equilibrium distribution functions for ions and electrons are expressed in terms of constants of motion and satisfy the steady-state Vlasov-Poisson equation system. Provided that the ion drift speed does not exceed the ion thermal speed, the equilibria can be specified with customizable density and electrostatic potential profiles. The methods can thereby be tailored to different applications and are successfully applied to construct kinetic equilibria for cross-field plasmas with sheared flows, large density variations, and different levels of magnetization. The equilibria are used to initialize fourth-order finite-volume Vlasov-Poisson simulations in (x, vx, vy) coordinates and the associated temporal evolution is used to assess the accuracy of each method. The low-amplitude deviations observed in these simulations demonstrate that the kinetic equilibria are robust and that they provide a valuable means of studying the dynamics of nonuniform magnetized plasmas.
The effect of fluid shear on oscillating bubbly flows
Authors: Lin Shengxiang , Lu Jiacai , Tryggvason Grétar , Zhang Ying
Published: April 2019

The impact of fluid shear on the bubble distribution in channel flows with periodically oscillating pressure gradient is examined by direct numerical simulations. Equal-sized and nearly circular bubbles are placed randomly in the channel at the initial time. In the absence of shear, the bubbles form columns spanning the width of the channel, but a strong enough shear breaks up the columns, leading to a more random bubble distribution. The effect of the nondimensional shear rate on the flow can be divided into low shear rate, moderate shear rate, and high shear rate regimes. The flow dynamics is also influenced by the Reynolds and the Euler number, and when these numbers decrease, the low shear rate regime, with stable tilted columns of bubbles, becomes smaller. Comparison of results for two- and three-dimensional flows shows that the dynamics observed in two-dimensional flows is also found in three dimensions.
Contact electrification between randomly rough surfaces with identical materials
Authors: Feshanjerdi M. , Malekan A.
Published: April 2019

We put a flat and a rough surface in contact and then separate them by the distance d. We calculate the work and the force needed to separate two surfaces. The theory is an extension of earlier researches by Persson, Scaraggi, and Volokitin. In addition to the effects of the roughness, we consider the effect of the fluctuations of charge density in the work of adhesion. The roughness increases the area of the surface and, consequently, an enhancement in the charge, growth in the force, and work of adhesion. When the density of charges is not constant, the roughness imposes a balanced distance between plates. As the balanced distance decreases, the roughness of the surface increases. To reach the distance less than the balanced, a downward force is needed. The comparison between the force of constant charge density and fluctuations of charges displays that the force of charge fluctuations has the larger magnitude than the constant charge, even with a charge density power spectrum 10−13 less than the square of the constant charge density.
Experimental demonstration of energy harvesting from the sky using the negative illumination effect of a semiconductor photodiode
Authors: Ono Masashi , Santhanam Parthiban , Li Wei , Zhao Bo , Fan Shanhui
Published: April 2019

We experimentally demonstrate electric power generation from the coldness of the universe directly, using the negative illumination effect when an infrared semiconductor diode faces the sky. Our theoretical model, accounting for the experimental results, indicates that the performance of such a power generation scheme is strongly influenced by the degree of matching between the responsivity spectrum and the atmospheric transparency window, as well as the quantum efficiency of the diode. A Shockley-Queisser analysis of an ideal optimized diode, taking into consideration the realistic transmissivity spectrum of the atmosphere, indicates the theoretical maximum power density of 3.99 W/m2 with the diode temperature at 293 K. The results here point to a pathway towards night-time power generation.
The physics of twin-fluid jet-in-crossflow at atmospheric and jet-engine operating conditions
Authors: Tan Zu Puayen
Published: April 2019

Efforts to mitigate jet engine emissions produced a class of swirl-stabilized combustors in which a rich pilot-flame in the center of the swirl-cup anchors an outer-annulus of lean-premixed main-flame. Fuel distribution within the annulus must be carefully controlled to allow stable combustion while avoiding excessive swirl-cup heating and flashbacks. This was traditionally achieved by placing plain jet-in-crossflow (JICF) fuel injectors around the swirl-cup; however, a recent increase in engine operating pressure and temperature along with demand for leaner fuel-air mixtures made the traditional approach untenable. Hence, modern swirl-cup designs begin to adopt a new fuel-injection technique called the “twin-fluid JICF (TF-JICF)” where a sleeve of air is co-injected with the liquid jet to modify its spray-pattern. TF-JICF is a nascent variation of the JICF that is not well understood, especially at elevated pressures. Hence, an experimental investigation of TF-JICF spray behaviors was performed by our group, covering the operating conditions of 1.5–9.5 atm in crossflow pressure, 175–1050 in crossflow Weber number, 5–40 in momentum flux-ratio, and 0%–150% in air-nozzle pressure-drop, at the crossflow temperature of 150 °C and velocity of 75 m/s. Part 1 of the investigation’s results, which identified four distinct flow regimes and nonmonotonic penetration trends in TF-JICF, was published in the work of Tan et al., “The regimes of twin-fluid jet-in-crossflow at atmospheric and jet-engine operating conditions,” Phy. Fluids 30, 025101 (2018). The current paper expands upon the previous report by elucidating key spray features and potential mechanisms (e.g., transitions between crossflow-driven atomization, air-driven shear-atomization, and air-driven prompt-atomization) within each TF-JICF regime, thereby providing a conceptual framework of TF-JICF for future studies.
Encapsulation of heavy metals by a nanoporous complex oxide 12CaO · 7Al2O3
Authors: Kuganathan Navaratnarajah , Grimes Robin W. , Chroneos Alexander
Published: April 2019

The nanoporous oxide 12CaO ⋅ 7Al2O3 (C12A7) offers the possibility of capturing large concentrations of environmentally damaging extra-framework species in its nanopores. Using density functional theory with a dispersion correction, we predict the structures and energetics of some heavy metals (Cr, Ni, Cu, Zn, Cd, Hg, and Pb) trapped by the stoichiometric and electride form of C12A7. In the stoichiometric form, while Zn, Cd, Hg, and Pb are encapsulated weakly, Cr, Ni, and Cu exhibit strong encapsulation energies. The electride form of C12A7 shows a significant enhancement in the encapsulation of Cr, Ni, Cu, and Pb. Successive encapsulation of multiple Cr, Ni, Cu, and Pb as single species in adjacent cages of C12A7 is also energetically favorable.
Geodesic interpolation for reaction pathways
Authors: Zhu Xiaolei , Thompson Keiran C. , Martínez Todd J.
Published: April 2019

The development of high throughput reaction discovery methods such as the ab initio nanoreactor demands massive numbers of reaction rate calculations through the optimization of minimum energy reaction paths. These are often generated from interpolations between the reactant and product endpoint geometries. Unfortunately, straightforward interpolation in Cartesian coordinates often leads to poor approximations that lead to slow convergence. In this work, we reformulate the problem of interpolation between endpoint geometries as a search for the geodesic curve on a Riemannian manifold. We show that the perceived performance difference of interpolation methods in different coordinates is the result of an implicit metric change. Accounting for the metric explicitly allows us to obtain good results in Cartesian coordinates, bypassing the difficulties caused by redundant coordinates. Using only geometric information, we are able to generate paths from reactants to products which are remarkably close to the true minimum energy path. We show that these geodesic paths are excellent starting guesses for minimum energy path algorithms.
Extension and acceleration of relativistic density functional theory based on transformed density operator
Authors: Ikabata Yasuhiro , Oyama Takuro , Hayami Masao , Seino Junji , Nakai Hiromi
Published: April 2019

We report an extension of relativistic density functional theory (RDFT) within one-component or two-component expressions that relies on a unitary-transformed density operator as well as a unitary-transformed Hamiltonian [Oyama et al., Chem. Phys. Lett. 680, 37 (2017)]. The transformed density operator is introduced to avoid the picture-change effect in the electron density, density gradient, kinetic energy density, and exchange-correlation potential. We confirmed that the implementation based on the spin-free infinite-order Douglas–Kroll–Hess method gives total, orbital, and excitation energies close to the reference values given by four-component RDFT calculations. To reduce the computational cost due to the transformed density operator, the local unitary transformation was also implemented. Numerical assessments revealed that the present scheme enabled the RDFT calculation of polyatomic systems with negligibly small picture-change effect.
Controlling rotational quenching rates in cold molecular collisions
Authors: Croft J. F. E. , Balakrishnan N.
Published: April 2019

The relative orientation and alignment of colliding molecules plays a key role in determining the rates of chemical processes. Here, we examine in detail a prototypical example: rotational quenching of HD in cold collisions with H2. We show that the rotational quenching rate from j = 2 → 0, in the v = 1 vibrational level, can be maximized by aligning the HD along the collision axis and can be minimized by aligning the HD at the so called magic angle. This follows from quite general helicity considerations and suggests that quenching rates for other similar systems can also be controlled in this manner.
A posteriori tests of subgrid-scale models in an isothermal turbulent channel flow
Authors: Dupuy D. , Toutant A. , Bataille F.
Published: April 2019

This paper studies the large-eddy simulation (LES) of isothermal turbulent channel flows. We investigate zero-equation algebraic models without wall function or wall model: functional models, structural models, and mixed models. In addition to models from the literature, new models are proposed and their relevance is examined. Dynamic versions of each type of model are also analyzed. The performance of the subgrid-scale models is assessed using the same finite difference numerical method and physical configuration. The friction Reynolds number of the simulations is 180. Three different mesh resolutions are used. The predictions of large-eddy simulations are compared to those of a direct numerical simulation filtered at the resolution of the LES meshes. The results are more accurate than those of a simulation without model. The predictions of functional eddy-viscosity models can be improved using constant-parameter or dynamic tensorial methods.
On the calculation of time-dependent electron momenta within the Born-Oppenheimer approximation
Authors: Schaupp Thomas , Engel Volker
Published: April 2019

In the case of an adiabatic motion in molecules, electrons adjust to the smoothly changing geometry of the nuclei. Although then the Born-Oppenheimer (BO) approximation is valid, it fails in predicting the time-dependence of electron momenta because, within its product ansatz for the wave function, the respective expectation values are zero. It is shown that this failure can be circumvented using the Ehrenfest theorem. Here we extend our former work [T. Schaupp et al., Eur. Phys. J. B 91, 97 (2018)] and regard models in higher dimensions and for more particles. We solve the time-dependent Schrödinger equation for the combined nuclear-electronic motion and compare the results to those derived from BO wave functions. For all situations, it is found that the time-dependent BO electronic momenta are in excellent agreement with the numerically exact results.
Thermal stability improvement of sintered Ag die-attach materials by addition of transition metal compound particles
Authors: Sugiura Kazuhiko , Iwashige Tomohito , Tsuruta Kazuhiro , Chen Chuantong , Nagao Shijo , Sugahara Tohru , Suganuma Katsuaki
Published: April 2019

Sintered silver (Ag) die-attach has attracted much attention in assembling power modules for high power density and high temperature operation. We have investigated a method to improve the thermal stability of a sintered Ag die-attach structure at high temperature storage (HTS). One of the issues of die-attach with sintered Ag is the growth of a microporous structure after HTS, since the microporous growth of the sintered Ag layer may have severe influence on bonding strength and reliability. It was verified that the addition of transition metal compound particles such as WO3, Nb2O5, MoO3, and RuO2 to sintered Ag paste successfully prevents microporous structure growth beyond 200 °C. From the results of cross-sectional scanning electron microscope observation, the inhibiting effect of microporous growth has a correlation with the difference between the total-circumference-length measured before and after HTS, among which WO3 and Nb2O5 additives were more effective. We propose this amazing die-attach material to power modules for high temperature operation providing excellent thermal stability.
Practical techniques to homogenize the feed gas mixture and enhance the laser-jet interaction time in laser assisted aerodynamic separation studies
Authors: Prasad M. B. Sai , Nilaya J. Padma , Ghosh Ayan , Nayak A. K. , Singh Vijendra , Kalburgi A. K. , Biswas D. J.
Published: April 2019

Laser assisted aerodynamic separation not only suffers from lengthy homogenization time of the feed gas mixture but also dilution of the enriched stream when the duration of the pulsed gas jet stream far exceeds that of the emission of the pulsed laser. We report here practical techniques to overcome the former and alleviate the latter by imposing forced circulation of the feed gas prior to affecting aerodynamic separation and the rim gas during the separation process, respectively. The forced circulation of the feed gas comprising the process gas and the buffer gas resulted in drastic reduction in the time required for their thorough mixing. The recirculation of the rim gas, on the other hand, back to the pulsed nozzle through the feed vessel allowed its increased interaction with the laser beam, thereby reducing the dilution of enrichment to a certain extent.
Variation in sequence dynamics improves maintenance of stereotyped behavior in an example from bird song
Authors: Duffy Alison , Abe Elliott , Perkel David J. , Fairhall Adrienne L.
Published: April 2019

Significance

In this work, we show a way by which the nervous system maintains precise, stereotyped behavior in the face of environmental and neural changes. Through a model of bird song learning, we show how instability in neural representation of stable behavior can allow a system to more readily adapt and maintain performance with minimal cost. In this perspective, behaviors are made more robust to environmental change by continually seeking subtly new ways of performing the same task. Thus, one should expect to find variability in neural systems executing stereotyped behaviors, and this variability can serve a constructive role in maintaining skilled behavior.
Global warming has increased global economic inequality
Authors: Diffenbaugh Noah S. , Burke Marshall
Published: April 2019

Significance

We find that global warming has very likely exacerbated global economic inequality, including ∼25% increase in population-weighted between-country inequality over the past half century. This increase results from the impact of warming on annual economic growth, which over the course of decades has accumulated robust and substantial declines in economic output in hotter, poorer countries—and increases in many cooler, wealthier countries—relative to a world without anthropogenic warming. Thus, the global warming caused by fossil fuel use has likely exacerbated the economic inequality associated with historical disparities in energy consumption. Our results suggest that low-carbon energy sources have the potential to provide a substantial secondary development benefit, in addition to the primary benefits of increased energy access.
Intergenerational transmission of the positive effects of physical exercise on brain and cognition
Authors: McGreevy Kerry R. , Tezanos Patricia , Ferreiro-Villar Iria , Pallé Anna , Moreno-Serrano Marta , Esteve-Codina Anna , Lamas-Toranzo Ismael , Bermejo-Álvarez Pablo , Fernández-Punzano Julia , Martín-Montalvo Alejandro , Montalbán Raquel , Ferrón Sacri R. , Radford Elizabeth J. , Fontán-Lozano Ángela , Trejo José Luis
Published: April 2019

Physical exercise has positive effects on cognition, but very little is known about the inheritance of these effects to sedentary offspring and the mechanisms involved. Here, we use a patrilineal design in mice to test the transmission of effects from the same father (before or after training) and from different fathers to compare sedentary- and runner-father progenies. Behavioral, stereological, and whole-genome sequence analyses reveal that paternal cognition improvement is inherited by the offspring, along with increased adult neurogenesis, greater mitochondrial citrate synthase activity, and modulation of the adult hippocampal gene expression profile. These results demonstrate the inheritance of exercise-induced cognition enhancement through the germline, pointing to paternal physical activity as a direct factor driving offspring’s brain physiology and cognitive behavior.
Preventing adolescent stress-induced cognitive and microbiome changes by diet
Authors: Provensi Gustavo , Schmidt Scheila Daiane , Boehme Marcus , Bastiaanssen Thomaz F. S. , Rani Barbara , Costa Alessia , Busca Kizkitza , Fouhy Fiona , Strain Conall , Stanton Catherine , Blandina Patrizio , Izquierdo Ivan , Cryan John F. , Passani Maria Beatrice
Published: April 2019

Significance

A healthy nutritional status is essential for proper brain development and for the maintenance of optimal cognitive function during adulthood and aging. The effects of ω-3 polyunsaturated fatty acids (ω-3 PUFAs) and vitamin supplementation or deficiency on neurodevelopment have been extensively studied in healthy infants and postweaning laboratory animals, but little is known about the influence of these micronutrients on the cognitive and neurochemical consequences of chronic stress during adolescence. We provide evidence that a diet supplemented with ω-3 PUFAs and vitamin A prevents deleterious cognitive impairment and shift of microbiota composition induced by social instability stress during adolescence, and that amelioration is maintained through adulthood, suggesting that a healthy diet may have long-lasting beneficial effects and help fight off neurodegenerative diseases.
In silico learning of tumor evolution through mutational time series
Authors: Auslander Noam , Wolf Yuri I. , Koonin Eugene V.
Published: April 2019

Significance

Cancer is caused by the effects of somatic mutations known as drivers. Although a number of major cancer drivers have been identified, it is suspected that many more comparatively rare and conditional drivers exist, and the interactions between different cancer-associated mutations that might be relevant for tumor progression are not well understood. We applied an advanced neural network approach to learn the sequence of mutations and the mutational burden in colon and lung cancers and to identify mutations that are associated with individual drivers. A significant ordering of driver mutations is demonstrated, and numerous, previously undetected conditional drivers are identified. These findings broaden the existing understanding of the mechanisms of tumor progression and have implications for therapeutic strategies.
Photoelectric conversion on Earth’s surface via widespread Fe- and Mn-mineral coatings
Authors: Lu Anhuai , Li Yan , Ding Hongrui , Xu Xiaoming , Li Yanzhang , Ren Guiping , Liang Jing , Liu Yuwei , Hong Hao , Chen Ning , Chu Shengqi , Liu Feifei , Li Yan , Wang Haoran , Ding Cong , Wang Changqiu , Lai Yong , Liu Juan , Dick Jeffrey , Liu Kaihui , Hochella Michael F.
Published: April 2019

Significance

In solar-terrestrial systems, solar energy input has long been recognized to have a profound impact on Earth. The well-known photosynthetic systems enable sustainable solar-to-chemical energy conversion. However, no evidence has yet emerged for the existence of a widespread geological light-harvesting system. This study reveals such a “photoelectric device,” where semiconducting Fe- and Mn (oxyhydr)oxide-mineral coatings are found to overlay vast expanses of natural rock/soil surfaces and exhibit highly responsive and stable photon-to-electron conversion. Our discovery may provide insight supporting vital photon-induced redox chemistry on Earth’s surface via widespread Fe- and Mn-mineral coatings.
A pair of native fungal pathogens drives decline of a new invasive herbivore
Authors: Clifton Eric H. , Castrillo Louela A. , Gryganskyi Andrii , Hajek Ann E.
Published: April 2019

Two North American fungal pathogens caused a coepizootic leading to localized collapse of an outbreak population of the newly invasive planthopper pest, the spotted lanternfly (
Lycorma delicatula
), in the eastern United States. The pathogens partitioned the habitat, with the majority of
L. delicatula
on tree trunks killed by
Batkoa major
, while cadavers of
L. delicatula
killed by
Beauveria bassiana
were usually on the ground. The future will show whether these pathogens will be drivers in boom–bust cycles or will result in recurrent low population densities of this new invasive species.
The effect of acute caffeine ingestion on upper and lower body anaerobic exercise performance
Authors: Duncan Michael J. , Eyre Emma , Grgic Jozo , Tallis Jason
Published: April 2019

The current study examined the effect of acute caffeine ingestion on mean and peak power production, fatigue index and rating of perceived exertion (RPE) during upper body and lower body Wingate anaerobic test (WANT) performance. Using a double‐blind design, 22 males undertook one upper body and one lower body WANT, 60 min following ingestion of caffeine (5 mg*kg−1) and one upper body and one lower body WANT following ingestion of placebo (5 mg*kg−1 Dextrose). Peak power was significantly higher (P = .001) following caffeine ingestion in both upper and lower body WANT. Peak power and mean power was also significantly higher during lower body, compared to upper body WANTs irrespective of substance ingested. However, caffeine ingestion did not enhance mean power neither in upper nor lower‐body WANT. There were no significant differences in mean fatigue index as a consequence of substance ingested or mode of exercise (all P > 0.05). For RPE there was also a significant substance ingested X mode interaction (P = .001) where there were no differences in RPE between caffeine and placebo conditions in lower body WANTs but significantly lower RPE during upper body WANT in the presence of caffeine compared to placebo (P = .014). This is the first study to compare the effects of caffeine ingestion on upper and lower body 30‐second WANT performance and suggests that caffeine ingestion in the dose of 5 mg*kg−1 ingested 60 min prior to exercise significantly enhances peak power when data from upper and lower body WANTs are combined.
Analysis of dislocation microstructure characteristics of surface grains under cyclic loading by discrete dislocation dynamics
Authors: El-Achkar T , Weygand D
Published: April 2019

The dislocation structure formation under low-amplitude fatigue infccmetals for multislip loading conditions is investigated using three-dimensional discrete dislocation dynamics. Tools based on graph analysis, a statistical description of stable dislocation arrangements such as dislocation dipoles and prismatic loops are developed and applied. Upon decreasing the loading amplitude one order of magnitude below the persistent slip band threshold, although qualitative microstructural differences are seen, the elementary features of the investigated defects are the same. A critical number of cycles is required to produce sessile Lomer junctions that stabilize the structure and result in dislocation clustering around them. The crystallographic orientation of the crystal with respect to the loading axis results in different patterns strongly linked to sessile junctions, which are analyzed using spatial correlation functions. The increase in irreversible bulk dislocation arrangements results in roughening of the free surface and increase in surface step heights. Furthermore the crystallographic orientation with respect to the free surface is shown to control the dislocation density evolution combined with the macroscopic Schmid factor.
Entanglement-enhanced optical gyroscope
Authors: Fink Matthias , Steinlechner Fabian , Handsteiner Johannes , Dowling Jonathan P , Scheidl Thomas , Ursin Rupert
Published: April 2019

Fiber optic gyroscopes (FOG) based on the Sagnac effect are a valuable tool in sensing and navigation and enable accurate measurements in applications ranging from spacecraft and aircraft to self-driving vehicles such as autonomous cars. As with any classical optical sensors, the ultimate performance of these devices is bounded by the shot-noise limit (SNL). Quantum-enhanced interferometry allows us to overcome this limit using non-classical states of light. Here, we report on an entangled-photon gyroscope that uses path-entangled NOON-states (N = 2) to provide super-resolution and phase sensitivity beyond the shot-noise limit.
Modelling of vorticity, sound and their interaction in two-dimensional superfluids
Authors: Forstner Stefan , Sachkou Yauhen , Woolley Matt , Harris Glen I , He Xin , Bowen Warwick P , Baker Christopher G
Published: April 2019

Vorticity in two-dimensional superfluids is subject to intense research efforts due to its role in quantum turbulence, dissipation and the BKT phase transition. Interaction of sound and vortices is of broad importance in Bose–Einstein condensates and superfluid helium. However, both the modelling of the vortex flow field and of its interaction with sound are complicated hydrodynamic problems, with analytic solutions only available in special cases. In this work, we develop methods to compute both the vortex and sound flow fields in an arbitrary two-dimensional domain. Further, we analyse the dispersive interaction of vortices with sound modes in a two-dimensional superfluid and develop a model that quantifies this interaction for any vortex distribution on any two-dimensional bounded domain, possibly non-simply connected, exploiting analogies with fluid dynamics of an ideal gas and electrostatics. As an example application we use this technique to propose an experiment that should be able to unambiguously detect single circulation quanta in a helium thin film.
Cost and Impact of Dried Blood Spot Versus Plasma Separation Card for Scale-up of Viral Load Testing in Resource-limited Settings
Authors: Nichols Brooke E , Girdwood Sarah J , Shibemba Aaron , Sikota Sharper , Gill Christopher J , Mwananyanda Lawrence , Noble Lara , Stewart-Isherwood Lynsey , Scott Lesley , Carmona Sergio , Rosen Sydney , Stevens Wendy
Published: April 2019

Background

Routine plasma viral load (VL) testing is recommended for monitoring human immunodeficiency virus–infected patients on antiretroviral therapy. In Zambia, VL scale-up is limited due to logistical obstacles around plasma specimen collection, storage, and transport to centralized laboratories. Dried blood spots (DBSs) could circumvent many logistical challenges at the cost of increased misclassification. Recently, plasma separation cards (PSCs) have become available and, though more expensive, have lower total misclassification than DBSs.

Methods

Using a geospatial model created for optimizing VL utilization in Zambia, we estimated the short-term cost of uptake/correct VL result using either DBSs or PSCs to increase VL access on equipment available in-country. Five scenarios were modeled: (1) plasma only (status quo); (2) plasma at high-volume sites, DBS at low-volume sites; (3) plasma at high-volume sites, PSC at low-volume sites; (4) PSC only; (5) DBS only.

Results

Scenario 1 resulted in 795 342 correct results due to limited patient access. When allowing for full and partial adoption of dried specimens, access increases by 19%, with scenario 3 producing the greatest number of correct results expected (929 857). The average cost per correct VL result was lowest in the plasma + DBS scenario at $30.90 compared to $31.62 in our plasma + PSC scenario. The cost per correct result of using dried specimens only was dominated in the incremental analysis, due primarily to fewer correct results.

Conclusions

Adopting the partial use of dried specimens will help achieve improved VL access for patients at the lowest cost per correct result.
British Cardiovascular Intervention Society registry framework: a quality improvement initiative on behalf of the National Institute of Cardiovascular Outcomes Research (NICOR)
Authors: Rashid Muhammad , Ludman Peter F , Mamas Mamas A
Published: April 2019

The British Cardiovascular Intervention Society (BCIS) percutaneous coronary intervention (PCI) registry is hosted by the National Institute of Cardiovascular Outcomes Research (NICOR) at Bart’s Heart Centre and collects clinical characteristics, indications, procedural details, and outcomes of all patients undergoing PCI in the UK. The data are used for audit and research to monitor and improve PCI practices and patient outcomes. Bespoke live data analysis and structured monthly reports are used to provide real-time feedback to all participating hospitals about the provision of care. Risk-adjusted analyses are used as a quality metric and benchmarking PCI practices. The consecutive patients undergoing PCI in all PCI performing hospitals in the UK from 1994 to present. One hundred and thirteen variables encompassing patient demographics, indication, procedural details, complications, and in-hospital outcomes are recorded. Prospective data are collected electronically and encrypted before transfer to central database servers. Data are validated locally and further range checks, sense checks, and assessments of internal consistency are applied during data uploads. Analyses of uploaded data including an assessment of data completeness are provided to all hospitals for validation, with repeat validation rounds prior to public reporting. Endpoints are in-hospital PCI complications, bleeding and mortality. All-cause mortality is obtained via linkage to the Office of National Statistics. No other linkages are available at present. Available for research by application to NICOR at http://www.nicor.org.uk/ using a data sharing agreement.
Age-related regulation and region-specific distribution of ion channel subunits promoting atrial fibrillation in human left and right atria
Authors: Biliczki Peter , Boon Reinier A , Girmatsion Zenawit , Bukowska Alicia , Ördög Balázs , Kaess Bernhard M , Hohnloser Stefan H , Goette Andreas , Varró András , Moritz Anton , Nattel Stanley , Ehrlich Joachim R
Published: April 2019

Aims 

Age-induced changes and electrical remodelling are important components of the atrial fibrillation (AF) substrate. To study regional distribution and age-dependent changes in gene expression that may promote AF in human atria.

Methods and results 

Human left atrial (LA) and right atrial (RA) tissue samples were obtained from donor hearts unsuitable for transplantation and from patients undergoing mitral valve repair. Atrial fibrillation was mimicked in vitro by tachypacing of human atrial tissue slices. Ionic currents were studied by the whole-cell patch-clamp technique; gene expression was analysed by real-time qPCR and immunoblotting. Both healthy RA and RA from older patients showed greater CACNA1c mRNA and CaV1.2 protein expression than LA. No age-dependent changes of Kir2.1 expression in both atria were seen. Remodelling occurred in a qualitatively similar manner in RA and LA. IK1 and Kir2.1 protein expression increased with AF. MiR-1, miR-26a, and miR-26b were down-regulated with AF in both atria. ICa,L was decreased. CACNA1c and CACNA2b expression decreased and miR-328 increased in RA and LA during AF. Ex vivo tachypacing of human atrial slices replicated these findings. There were age-dependent increases in miR-1 and miR-328, while miR-26a decreased with age in atrial tissues from healthy human donor hearts.

Conclusion 

Features of electrical remodelling in man occur in a qualitatively similar manner in both human atria. Age-related miR-328 dysregulation and reduced ICa,L may contribute to increased AF susceptibility with age.
Gazelles and muppets in the city: risk sharing and firm growth quantiles in a junior stock market
Authors: Abbate Cosimo , Sapio Alessandro
Published: April 2019

Financialization is persuading academics and policy-makers that the growth of SMEs can be unleashed by promoting their quotation on stock markets. Is it true? Answering can give clues on the functions that stock markets actually perform in the financialized world, from collecting finance for productive investments, to providing opportunities for value extraction; from a selection device to a risk-sharing mechanism. The associated effects may be amplified in segments catering to companies that do not satisfy the listing requirements of the official list, such as junior markets. In this article, we test hypotheses linking the shape of the firm growth rates distribution to the functions performed by a junior stock market, through quantile regressions. We use a sample of UK manufacturing companies listed on Alternative Investment Market (AIM), the junior segment of the London Stock Exchange, and comparably small and young unlisted companies. We find that the operating revenues and total assets of AIM-listed gazelles grow faster than for their unlisted peers, after controlling for lagged values of size, age, and growth. Yet, there is a loss reinforcing effect for companies listed on the AIM. After controlling for endogeneity by estimating instrumental variable quantile treatment effects, our findings dismiss the existence of a treatment effect of AIM and are consistent with the stock market attracting relatively risky companies.