bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of nozzle curvature on supersonic gas jets used in laser–plasma acceleration
Authors: Zhou Ocean , Tsai Hai-En , Ostermayr Tobias M. , Fan-Chiang Liona , van Tilborg Jeroen , Schroeder Carl B. , Esarey Eric , Geddes Cameron G. R.
Published: September 2021

Supersonic gas jets produced by converging–diverging nozzles are commonly used as targets for laser–plasma acceleration (LPA) experiments. A major point of interest for these targets is the gas density at the region of interaction where the laser ionizes the gas plume to create a plasma, providing the acceleration structure. Tuning the density profiles at this interaction region is crucial to LPA optimization. A “flat-top” density profile is desired at the line of interaction to control laser propagation and high-energy electron acceleration, while a short high-density profile is often preferred for acceleration of lower-energy tightly focused laser–plasma interactions. A particular design parameter of interest is the curvature of the nozzle's diverging section. We examine three nozzle designs with different curvatures: the concave “bell,” straight conical, and convex “trumpet” nozzles. We demonstrate that for mm-scale axisymmetric nozzles that, at mm-scale distances from the nozzle exit, curvature significantly impacts shock formation and the resulting gas jet density field and, therefore, is an essential parameter in LPA gas jet design. We show that bell nozzles are able to produce focused regions of gas with higher densities. We find that the trumpet nozzle, similar to straight and bell nozzles, can produce flat-top profiles if optimized correctly and can produce flatter profiles at the cost of slightly wider edges. An optimization procedure for the trumpet nozzle is derived and compared to the straight nozzle optimization process. We present results for different nozzle designs from computational fluid dynamics simulations performed with the program ANSYS Fluent and verify them experimentally using neutral density interferometry.
Radiative lifetime and dynamics of trions in few-layered ReS2
Authors: Wang Xiaofan , Shinokita Keisuke , Matsuda Kazunari
Published: September 2021

Few-layered ReS2 with anisotropic electrical and optical properties has attracted much attention in the research field of two-dimensional (2D) materials. Recently, a stable charged exciton (trion) composed of bound states of two electrons and a hole with large binding energy has been experimentally observed in a few-layered ReS2. However, the dynamics of stable trions remain unclear. We studied the excited-state dynamics, including the radiative lifetime of the negative trion in three layer (3L)-ReS2 via temperature-dependent photoluminescence spectroscopy and phenomenological rate-equation analysis. The derived radiative lifetime of the trion increases linearly with increasing temperature, reaching a few nanoseconds at a high temperature of 150 K; this observation implies that the experimentally observed negative trion in 3L-ReS2 lies in the optically allowed state. Our results provide significant insights into the physics of excitonic states in 2D materials.
Ultrathin space charge layer in hematite photoelectrodes: A theoretical investigation
Authors: Delcompare-Rodriguez P. A. , Seriani N.
Published: September 2021

The space charge layer in hematite photoelectrodes has been analyzed by means of Poisson–Boltzmann equations, the Stern model, and density functional theory, in view of its application for photoelectrochemical water oxidation. The width of the space charge layer can be smaller than ∼10 Å under experimental conditions. In this regime, a substantial part of the potential drop takes place in the Helmholtz layer, leading to important corrections to the Mott–Schottky behavior of the space charge layer capacitance. These results shed light on an unexpected regime of high photoelectrocatalytic efficiency, different from the classical picture of the electrochemical interface of a semiconducting photocatalyst, which is also amenable to direct study by quantum-mechanical atomistic simulations. Density functional theory has been used to calculate the band bending (BB) in the space charge layer in atomistic models of pristine stoichiometric and hydroxylated surfaces. These surface terminations display BBs of 0.14 and 0.49 eV, respectively, with an increasing width of the space charge layer, however still in the sub-nanometer regime. This work shows that, at high doping, the width of the space charge layer of a hematite photoelectrode can become comparable with interatomic distances.
Reduced-model scrape-off layer turbulence (nSOLT) simulations comparing three fueling scenarios
Authors: Russell D. A. , Myra J. R. , Militello F. , Moulton D.
Published: September 2021

The 2D scrape-off-layer turbulence code (nSOLT) includes 1D Boltzmann neutral–plasma interactions, a model of divertor recycling (introduced here), and a fixed source of plasma concentrated at the core-side boundary. Three fueling methods are considered herein: (1) neutral injection in the far-SOL is accomplished by specifying the density of Franck–Condon distributed neutrals streaming in from the boundary. (2) Divertor recycling is modeled by injecting a fraction of the particle parallel flux in the scrape-off layer (SOL) back into the edge region as a source of plasma. (3) A constant source fuels the edge plasma from the core-side boundary to model pellet injection. For machine parameters (B, Rm, and L//) illustrative of the MAST-U device, and for a deuterium plasma, turbulent equilibria are obtained that share the same plasma fueling rate for each of the three fueling methods, with only one of the sources on in each case. In the presence of self-consistent turbulence, quasi-steady plasma and neutral (deuterium) profiles, fueling efficiencies, SOL transparencies, and heat flux widths are compared. Characteristics of the turbulent fluctuations, including skewness, cross-phases, and power spectra, are described. The calculated fueling efficiencies, SOL transparencies to neutral penetration, and many of the turbulent properties are remarkably similar for all three fueling methods despite significant differences in the plasma profiles. The nonlinear states of the three cases are dominated by separatrix-spanning vortex cells that control particle and heat losses into the SOL.
Dynamics of Ar metastable and resonance states in pulsed capacitively coupled plasmas
Authors: Kovalev A. S. , Rakhimova T. V. , Rakhimov A. T. , Proshina O. V. , Vasilieva A. N. , Voloshin D. G.
Published: September 2021

The experimental and theoretical study of radiofrequency capacitively coupled plasma discharge afterglow has been carried out. Temporal dynamics of Ar metastable and resonance states densities are measured by the absorption method with separate capacitive discharge as a radiation source. The collision radiative model is applied to calculate the corresponding dynamics of Ar excited states in the afterglow with electron density and temperature obtained from self-consistent particle in cell simulation. Different temporal dynamics for metastable and for resonance states densities are revealed and explained. The numerical results and experimental data on Ar excited state dynamics are in good agreement with each other. The decrease in vacuum ultraviolet photon fluxes from the discharge to the substrate is shown. The possible damage free time for plasma treatment of specific dielectric film in a pulsed discharge regime is estimated.
Nonequilibrium thermodynamics of light-induced reactions
Authors: Penocchio Emanuele , Rao Riccardo , Esposito Massimiliano
Published: September 2021

Current formulations of nonequilibrium thermodynamics of open chemical reaction networks only consider chemostats as free-energy sources sustaining nonequilibrium behaviors. Here, we extend the theory to include incoherent light as a source of free energy. We do so by relying on a local equilibrium assumption to derive the chemical potential of photons relative to the system they interact with. This allows us to identify the thermodynamic potential and the thermodynamic forces driving light-reacting chemical systems out-of-equilibrium. We use this framework to treat two paradigmatic photochemical mechanisms describing light-induced unimolecular reactions—namely, the adiabatic and diabatic mechanisms—and highlight the different thermodynamics they lead to. Furthermore, using a thermodynamic coarse-graining procedure, we express our findings in terms of commonly measured experimental quantities, such as quantum yields.
A differential thin film resistance thermometry method for peak thermal conductivity measurements of high thermal conductivity crystals
Authors: Zhou Yuanyuan , Li Chunhua , Broido David , Shi Li
Published: September 2021

High thermal conductivity materials are useful for thermal management applications and fundamental studies of phonon transport. Past measurements of several ultrahigh thermal conductivity materials were not able to obtain the peak thermal conductivity, which is expected to appear at a low temperature and contains insight into the competition between extrinsic phonon-defect and phonon-boundary scattering with intrinsic phonon–phonon processes. Here, we report a peak thermal conductivity measurement method based on differential Wheatstone bridge measurement of the small temperature drop between two thin film resistance thermometers patterned directly on the sample. With the use of a mesoscale silicon bar sample as the calibration standard, this method is able to obtain results that agree with past measurements of large bulk silicon crystals at high temperatures and first-principles calculation results that account for additional phonon-boundary scattering in the sample. The agreement demonstrates the accuracy of this measurement method for peak thermal conductivity measurements of high thermal conductivity materials.
Explore missing flow dynamics by physics-informed deep learning: The parameterized governing systems
Authors: Xu Hui , Zhang Wei , Wang Yong
Published: September 2021

Gaining and understanding flow dynamics have much importance in a wide range of disciplines, e.g., astrophysics, geophysics, biology, mechanical engineering, and biomedical engineering. For turbulent flows, local flow information such as velocity and its statistics, can be measured experimentally. Due to the poor fidelity or experimental limitations, some information may not be resolved in a region of interest. On the other hand, detailed flow features are described by the governing equations, e.g., the Navier–Stokes equations for viscous fluid, and can be resolved numerically, which is heavily dependent on the capability of either computing resources or modeling. Alternatively, we address this problem by employing the physics-informed deep learning and treat the governing equations as a parameterized constraint to recover the missing flow dynamics. We demonstrate that with limited data, no matter from experiment or others, the flow dynamics in the region where the required data are missing or not measured, can be reconstructed with the parameterized governing equations. Meanwhile, a richer dataset, with spatial distribution of the control parameter (e.g., eddy viscosity of turbulence modelings), can be obtained. The method provided in this paper may shed light on the data-driven scale-adaptive turbulent structure recovering and understanding of complex fluid physics and can be extended to other parameterized governing systems beyond fluid mechanics.
Anharmonic fundamental vibrational frequencies and spectroscopic constants of the potential HSO2 radical astromolecule
Authors: Fortenberry Ryan C. , Francisco Joseph S.
Published: September 2021

The recent report that HSO2 is likely kinetically favored over the HOSO thermodynamic product in hydrogen addition to sulfur dioxide in simulated Venusian atmospheric conditions has led to the need for reference rotational, vibrational, and rovibrational spectral data for this molecule. While matrix-isolation spectroscopy has been able to produce vibrational frequencies for some of the vibrational modes, the full infrared to microwave spectrum of 1 2A′ HSO2 is yet to be generated. High-level quantum chemical computations show in this work that the >2.5 D dipole moment of this radical makes it a notable target for possible radioastronomical observation. Additionally, the high intensity antisymmetric S–O stretch is computed here to be 1298.3 cm−1, a 13.9 cm−1 blueshift up from H2 matrix analysis. In any case, the full set of rotational and spectroscopic constants and anharmonic fundamental vibrational frequencies is provided in this work in order to help characterize HSO2 and probe its kinetic favorability.
Perspective on witnessing entanglement in hybrid quantum systems
Authors: Mao Yingqiu , Gong Ming , Nemoto Kae , Munro William J. , Majer Johannes
Published: September 2021

Hybrid quantum systems aim at combining the advantages of different physical systems and producing innovative quantum devices. In particular, the hybrid combination of superconducting circuits and spins in solid-state crystals is a versatile platform to explore many quantum electrodynamics problems. Recently, the remote coupling of nitrogen-vacancy center spins in diamond via a superconducting bus was demonstrated. However, a rigorous experimental test of the quantum nature of this hybrid system and, in particular, entanglement is still missing. We review the theoretical ideas to generate and detect entanglement and present our own scheme to achieve this.
Proton irradiation effects on InGaAs/InAsSb mid-wave barrier infrared detectors
Authors: Carrasco Rigo A. , George James , Maestas Diana , Alsaad Zinah M. , Garnham David , Morath Christian P. , Duran Joshua M. , Ariyawansa Gamini , Webster Preston T.
Published: September 2021

Semiconductor-based mid-wave infrared photon detectors that functionalize space-based imaging systems are susceptible to both cumulative ionization and displacement damage, especially due to proton irradiation. Here, the dark current density and quantum efficiency of a mid-wave infrared detector utilizing a strain-balanced InGaAs/InAsSb superlattice active region are examined as a function of a 63 MeV proton radiation dose. Proton-irradiation is performed in an incremental stepwise dose up to a total ionizing dose of 100 krad(Si) or an equivalent proton fluence of 6.1 × 1011 protons/cm2. All characterization work is conducted with the detectors held at an operating temperature of 130 K throughout the experiment to limit thermal annealing effects. Prior to irradiation, the quantum efficiency of the top-side illuminated device without anti-reflection coating is 59.5%. The quantum efficiency is largely independent of temperature below 150 K, indicative of an electron minority carrier. As irradiation progressed the typical linear increase in inverse quantum efficiency with increasing proton fluence was observed, which led to a quantum efficiency damage factor of 1.12 × 1013 e cm2/ph. This value is shown to be an order of magnitude lower than typically observed in III-V nBn devices and is likely due to the higher mobility of minority electrons in the active region of this device. A full analysis of the characterization results suggests that displacement damage creates a significant population of donor states that modify the doping profile, in addition to Shockley–Read–Hall recombination centers that generally form as a result of proton irradiation.
Engineering the nature of polarization dynamics in lead-free relaxors based on (Bi1/2Na1/2)TiO3
Authors: Fan Zhongming , Randall Clive A.
Published: September 2021

(Bi1/2Na1/2)TiO3 (BNT) is a lead-free ferroelectric material, which has shown promising electromechanical properties and energy storage capacities. These attractive functionalities and property performances are attributed to the relaxor behavior of BNT. However, the nature of the dielectric relaxation is not well understood in these materials, and the physical meaning of some important parameters associated with the permittivity is still under debate. In this Letter, we focus on the dielectric “shoulder,” Ts, that is readily seen in the ε′–T curve of every BNT-based relaxor. It is found that the Ts is controlled by not only the typical compositional engineering but also by the thermal, electrical, or mechanical history. From a moderate temperature (≤250 °C), a sample can be rapidly cooled to room temperature or slowly cooled under an electrical bias or a mechanical bias in the form of a compressive stress. All three treatments lead to a nearly identical effect, which is to alter the Ts with respect to rest of the ε′–T curve that remains unperturbed. Therefore, the internal stress is identified to be a general perturbance to the polarization dynamics. Finally, the “breathing” model is revisited to interpret the physical meaning of Ts for these BNT materials under these metastable conditions.
Coronavirus induces diabetic macrophage-mediated inflammation via SETDB2
Authors: Melvin William J. , Audu Christopher O. , Davis Frank M. , Sharma Sriganesh B. , Joshi Amrita , DenDekker Aaron , Wolf Sonya , Barrett Emily , Mangum Kevin , Zhou Xiaofeng , Bame Monica , Ruan Alex , Obi Andrea , Kunkel Steven L. , Moore Bethany B. , Gallagher Katherine A.
Published: September 2021

Significance

The COVID-19 pandemic has disproportionately affected patients with comorbidities, namely, obesity and type 2 diabetes. Macrophages (Mφs) are a key innate immune cell primarily responsible for the harmful, hyperinflammatory “cytokine storm” in patients that develop severe COVID-19. We describe a mechanism for this Mφ-mediated cytokine storm in response to coronavirus. In response to coronavirus infection, expression of the chromatin-modifying enzyme, SETDB2, decreases in Mφs, leading to increased transcription of inflammatory cytokines. Further, we find SETDB2 is regulated by an interferon beta (IFNβ)/JaK/STAT3 mechanism, and that exogenous administration of IFNβ can reverse inflammation, particularly in diabetic Mφs via an increase in SETDB2. Together, these results suggest therapeutic targeting of the IFNβ/SETDB2 axis in diabetic patients with COVID-19 may decrease pathologic inflammation.
Disabling de novo DNA methylation in embryonic stem cells allows an illegitimate fate trajectory
Authors: Kinoshita Masaki , Li Meng Amy , Barber Michael , Mansfield William , Dietmann Sabine , Smith Austin
Published: September 2021

Significance

Mammalian DNA is widely modified by methylation of cytosine residues. This modification is added to DNA during early development. If methylation is prevented, the embryo dies by midgestation with multiple abnormalities. In this study we found that stem cells lacking the DNA methylation enzymes do not differentiate efficiently into cell types of the embryo and are diverted into producing placental cells. This switch in cell fate is driven by a transcription factor, Ascl2, which should only be produced in the placenta. In the absence of DNA methylation, theAscl2gene is misexpressed. Removing Ascl2 redirects embryonic fate but not full differentiation potential, suggesting that methylation acts at multiple developmental transitions to restrict activation of disruptive genes.
Frustrated peptide chains at the fibril tip control the kinetics of growth of amyloid-β fibrils
Authors: Xu Yuechuan , Knapp Kaitlin , Le Kyle N. , Schafer Nicholas P. , Safari Mohammad S. , Davtyan Aram , Wolynes Peter G. , Vekilov Peter G.
Published: September 2021

Significance

Amyloid fibril growth is a probable key step in Alzheimer’s disease pathogenesis, and growing fibril tips may represent the “Achilles’ heel” of the process. We combine thermodynamic and kinetic experiments at the single-fibril level with molecular modeling, exclusively focused on events at the fibril tip. The experiments provide strong evidence for the role of frustrated intermediate states in fibrillization. The frustrated intermediates provide fresh targets in the search for potential drugs for Alzheimer’s disease.
Cause for optimism
Authors: Červinková Poesová Kristýna , Lancová Klára
Published: September 2021

The current chapter explores the beliefs and
attitudes of Czech pre-service teachers towards native and
non-native accents. Specifically, we were interested in how accent
attitudes contribute to the process of forming non-native teacher
identities, viewed from both real and imagined L2 user/teacher
perspectives. On the one hand, the results indicate a growing
acceptance of one’s accentedness and, simultaneously, a highly
motivational character of native-like aspirations. On the other
hand, English teachers are perceived as role models and,
consequently, a high standard of performance is expected in terms of
nativeness. We argue that more emphasis should be placed on
excellence in pedagogical skills in teacher training in order to
counterbalance the unattainability of the imagined native
selves.
Contractions, constructions and constructional change
Authors: Daugs Robert
Published: September 2021

In this paper, I argue that construction grammarians may
have to consider integrating modal contractions into the English modal
system as distinct constructions rather than variants of their uncontracted
forms. Based on data from COHA, it can be shown that the contractions
investigated here have emancipated themselves from the full forms both in
terms of relative usage frequency as well as function over the past two
centuries, thus yielding a series of constructional changes. From a
usage-based, constructionist perspective, these results contribute to
modelling the modal network as possibly represented in the minds of
speakers, but they also support the understanding that this network appears
to be much more heterogeneous than perhaps desired (by some linguists).
Exploring relative degrees of auxiliarization empirically in German modal
constructions with wissen and
verstehen
Authors: Dekalo Volodymyr
Published: September 2021

The present paper investigates which sort of
information – item- or feature-based – is more sufficient to quantify
relative degrees of auxiliarization. To understand this issue, the study
utilizes two German near-synonymous semi-schematic modal constructions with
wissen and verstehen. Sketching the
notion of host class expansion, the paper shows that the evidence of host
class expansion by gauging type frequency of co-occurring elements is often
used to demonstrate the increasing grammaticalization of a construction
within usage-based construction grammar. Applying a mixed-effects binary
logistic regression, the study ascertains a difference in the relative
degree of grammaticalization between the wissen- and
verstehen-construction by means of such usage features
as (a) the position of verbal complements, (b) the grammatical form of modal
auxiliaries, and (c) the animacy of subject referents. Comparing these
results with the counts of the co-occurring element types of each modal
construction, the analysis reveals that they contradict each other. As a
result, the usage feature-based behavior is considered to be more important
for deciding the relative degree of grammaticalization of semi-schematic
constructions than host class expansion.
Grammaticalization of verdienen into an auxiliary marker
of deontic modality
Authors: Diewald Gabriele , Dekalo Volodymyr , Czicza Dániel
Published: September 2021

This paper investigates synchronic variation in the
lexical and grammatical environments of the German lexical verb
verdienen ‘earn’, ‘deserve’. In its lexical uses,
verdienen co-occurs with an object noun phrase whose
head is either concrete (e.g. Geld ‘money’) or, more
commonly, abstract (e.g. Beachtung ‘attention’). When it is
used more grammatically with deontic modal meaning,
verdienen is followed by a passive or active
infinitive. This paper uses collostructional analyses to contrast lexical
and grammatical uses in terms of the most strongly attracted lexical items,
which are grouped into semantic classes. The results reflect different
degrees of host-class expansion (cf. Himmelmann 2004), whereby the collexemes of
verdienen expand from concrete to abstract and their
morpho-syntactic contexts from nominal to infinitival complement and
subsequently from passive to active. Synchronic distribution can thus serve
as a window on diachronic development (Kuteva 2001), in this case the rise of a deontic modality
marker.
Horizontal links within and between paradigms
Authors: Smirnova Elena
Published: September 2021

This paper deals with the constructional network of
reported directive speech acts in German. It addresses two aspects of
modality and constructions by relating directly to questions raised in the
introduction to this volume: the notion of the paradigm in Construction
Grammar on the one hand and the nature of the links within the
constructional network model on the other. By investigating the network of
syntactic constructions of reported directives in German, the paper focuses
on the modelling of two types of horizonal paradigmatic links between these
constructions: the links between allostructions and the links between
paradigmatic choices. On the conceptual level, the paper argues that these
two types of paradigmatic links constitute two different types of horizontal
links in the network. On the empirical level, the study demonstrates how
these horizontal links manifest themselves in the corpus data.
From stakeholder education to engagement, using strategies from social science.
Authors: Ventura Beth , Fjæran Erica Hogstad
Published: September 2021

This chapter describes the challenges that arise when animal practitioners attempt to address the public regarding animal welfare rely on one-way education alone. Animal practitioners may benefit from a reimagining of what effective public engagement to improve animal welfare may look like.
High-temperature oxidation and reduction of the inverse ceria/Cu(111) catalyst characterized by LEED, STM, nc-AFM and KPFM
Authors: El Barraj Ali , Chatelain Baptiste , Barth Clemens
Published: September 2021

The inverse catalyst ‘cerium oxide (ceria) on copper’ has attracted much interest in recent time because of its promising catalytic activity in the water–gas-shift reaction and the hydrogenation of CO2. For such reactions it is important to study the redox behaviour of this system, in particular with respect to the reduction by H2. Here, we investigate the high-temperature O2 oxidation and H2 reduction of ceria nanoparticles (NPs) and a Cu(111) support by low energy electron diffraction (LEED), scanning tunnelling microscopy (STM), non-contact atomic force microscopy (nc-AFM) and Kelvin probe force microscopy (KPFM). After oxidation at 550 °C, the ceria NPs and the Cu(111) support are fully oxidized, with the copper oxide exhibiting a new oxide structure as verified by LEED and STM. We show that a high H2 dosage in the kilo Langmuir range is needed to entirely reduce the copper support at 550 °C. A work function (WF) difference of △ϕ
rCeria/Cu–Cu ≈ −0.6 eV between the ceria NPs and the metallic Cu(111) support is measured, with the Cu(111) surface showing no signatures of separated and confined surface regions composed by an alloy of Cu and Ce. After oxidation, the WF difference is close to zero (△ϕ
Ceria/Cu–Cu ≈ −0.1…0 eV), which probably is due to a WF change of both, ceria and copper.
Measures maximizing the entropy for Kan endomorphisms
Authors: Núñez-Madariaga Bárbara , Ramírez Sebastián A , Vásquez Carlos H
Published: September 2021

In 1994, Kan provided the first example of maps with intermingled basins. The Kan example corresponds to a partially hyperbolic endomorphism defined on a surface, with the boundary exhibiting two intermingled hyperbolic physical measures. Both measures are supported on the boundary, and they also maximize the topological entropy. In this work, we prove the existence of a third hyperbolic measure supported in the interior of the cylinder that maximizes the entropy. We also prove this statement for a larger class of invariant measures of large class maps including perturbations of the Kan example.
Effective bounds for monochromatic connectivity measures in two dimensions
Authors: de Courcy-Ireland Matthew , Eswarathasan Suresh
Published: September 2021

We establish numerical lower bounds for the monochromatic connectivity measure in two dimensions introduced by Sarnak and Wigman. This measure dictates among the nodal domains of a random plane wave what proportion have any given number of holes, and how they are nested. Our bounds provide the first effective estimate for the number of simply connected domains and for those that contain a single hole. The deterministic aspect of the proof is to find a single function with a prescribed zero set and, using a quantitative form of the implicit function theorem, to argue that the same configuration occurs in the zero set of any sufficiently close approximation to this function. The probabilistic aspect is to quantify the likelihood of a random wave being close enough to this function.
Gevrey stability of hydrostatic approximate for the Navier–Stokes equations in a thin domain
Authors: Wang Chao , Wang Yuxi , Zhang Zhifei
Published: September 2021

In this paper, we justify the limit from the Navier–Stokes system in a thin domain to the hydrostatic Navier–Stokes/Prandtl system for the convex initial data with Gevrey 9/8 regularity in x.
Stability of the multi-solitons of the modified Korteweg–de Vries equation
*
Authors: Le Coz Stefan , Wang Zhong
Published: September 2021

We establish the nonlinear stability of N-soliton solutions of the modified Korteweg–de Vries (mKdV) equation. The N-soliton solutions are global solutions of mKdV behaving at (positive and negative) time infinity as sums of one-solitons with speeds 0 < c
1 <…< c

N
. The proof relies on the variational characterization of N-solitons. We show that the N-solitons realize the local minimum of the (N + 1)th mKdV conserved quantity subject to fixed constraints on the N first conserved quantities. To this aim, we construct a functional for which N-solitons are critical points, we prove that the spectral properties of the linearization of this functional around an N-soliton are preserved on the extended timeline, and we analyze the spectrum at infinity of linearized operators around one-solitons. The main new ingredients in our analysis are a new operator identity based on a generalized Sylvester law of inertia and recursion operators for the mKdV equation.
Quadrature domains and the real quadratic family
Authors: Lazebnik Kirill
Published: September 2021

We study several classes of holomorphic dynamical systems associated with quadrature domains. Our main result is that real-symmetric polynomials in the principal hyperbolic component of the Mandelbrot set can be conformally mated with a congruence subgroup ofPSL(2,Z)\mathrm {PSL}(2,\mathbb {Z}), and that this conformal mating is the Schwarz function of a simply connected quadrature domain.
Song varies with latitude, climate, and species richness in a Neotropical bird
Authors: Silva-Jr Edvaldo F , Diniz Pedro , Macedo Regina H
Published: September 2021

Animals can encode information within acoustic signals, particularly, bird songs can be remarkably complex and can indicate individual identity and quality. Two main sets of hypotheses attempt to explain the evolution of increased birdsong complexity across large-scale geographic ranges: 1) larger acoustic space availability, and 2) greater sexual selection intensity, both of which would favor the evolution of more complex songs at higher latitudes, more seasonal and/or species-poor environments. However, few studies have assessed patterns of song complexity for birds with broad geographic ranges. Here, we determined patterns of song variation in the blue-black grassquit (Volatinia jacarina), considering metrics of song complexity, structure and performance. This Neotropical bird occurs from Mexico to Argentina and produces a monosyllabic song. Using recordings from online databases, we calculated song metrics, such as bandwidth, song rate, number of song components, and proportion of vibratos of this signal. We found that song features varied with latitude, climate seasonality, bird species richness, and hemisphere. However, contrary to theoretical predictions, complexity mostly decreased with latitude and greater seasonality, while it was positively correlated with bird species richness. Proportion of vibratos was positively correlated with latitude and seasonality, and may be a feature under sexual selection in this species. Overall, our results did not support the main hypotheses proposed as explanations for song complexity. Our findings also highlight that song complexity does not vary uniformly among songbirds and song parameters, and future studies encompassing more species should clarify patterns and drivers of song variation across broad geographic dimensions.
The rise and fall of Neotropical biodiversity
Authors: Antonelli Alexandre
Published: September 2021

The exceptional levels of biodiversity found today in the American tropics are the outcome of tens of millions of years of evolution, shaped by the tumultuous geological history of the region, its heterogeneous habitats, climate change, ecological interactions and, in recent millennia, human influence. Although our understanding of diversity patterns and their underlying processes grows steadily in breadth and depth, Neotropical biodiversity is rapidly breaking down. Here, I contrast the long-term evolution of Neotropical biodiversity with its recent and rapid deterioration due to anthropogenic factors. I consider the impacts of the early arrival of humans to the region and the modern intensification of land-use change (primarily driven by agriculture) and other drivers of biodiversity loss, such as direct exploitation, invasive species and climate change. Together, these threats have led to 33% of all Neotropical species for which sufficient data are available being currently threatened with extinction. I outline emerging opportunities for conservation and restoration under the post-2020 Global Biodiversity Framework and call for urgent action from the biodiversity community, for the benefit of people and nature.
Community-based paralegals to build just societies: insights from a legal empowerment project in Pakistan
Authors: Cheema Abdur Rehman , Riaz Mehvish
Published: September 2021

The provision of rule of law and justice contributes to the building of equitable, inclusive, and economically prosperous societies. However, mere legal protection of the rights of the people in developing societies remains insufficient to ensure due protections guaranteed by the law. This study examines the impact of a legal empowerment project in the two districts of rural Punjab in Pakistan through key informant interviews and focus group discussions. The findings show that the project leads to awareness and fulfilment of rights, financial empowerment, agency development, especially of women, and reduction of oppression, exploitation, and injustice. It plays a significant role in building inclusive and sustainable societies where accountable public services are available and accessible to all without discrimination. This study emphasizes how the state including public and private administrative bodies should instead of oppressing, exploiting, or ignoring the needy masses create opportunities for them and develop their set of capabilities. This multidimensional paralegal assistance model rooted in existing community-based structures and support is scalable and adaptable.
Structural Covariance of Depth-Dependent Intracortical Myelination in the Human Brain and Its Application to Drug-Naïve Schizophrenia: A T1w/T2w MRI Study
Authors: Wei Wei , Yin Yubing , Zhang Yamin , Li Xiaojing , Li Mingli , Guo Wanjun , Wang Qiang , Deng Wei , Ma Xiaohong , Zhao Liansheng , Palaniyappan Lena , Li Tao
Published: September 2021

Aberrations in intracortical myelination are increasingly being considered as a cardinal feature in the pathophysiology of schizophrenia. We investigated the network-level distribution of intracortical myelination across various cortex depths. We enrolled 126 healthy subjects and 106 first-episode drug-naïve schizophrenia patients. We used T1w/T2w ratio as a proxy of intracortical myelination, parcellated cortex into several equivolumetric surfaces based on cortical depths and mapped T1w/T2w ratios to each surface. Non-negative matrix factorization was used to generate depth-dependent structural covariance networks (dSCNs) of intracortical myelination from 2 healthy controls datasets—one from our study and another from 100-unrelated dataset of the Human Connectome Project. For patient versus control comparisons, partial least squares approach was used; we also related myelination to clinical features of schizophrenia. We found that dSCNs were highly reproducible in 2 independent samples. Network-level myelination was reduced in prefrontal and cingulate cortex and increased in perisylvian cortex in schizophrenia. The abnormal network-level myelination had a canonical correlation with symptom burden in schizophrenia. Moreover, myelination of prefrontal cortex correlated with duration of untreated psychosis. In conclusion, we offer a feasible and sensitive framework to study depth-dependent myelination and its relationship with clinical features.
Safety and Immunogenicity of an Inactivated Severe Acute Respiratory Syndrome Coronavirus 2 Vaccine in a Subgroup of Healthy Adults in Chile
Authors: Bueno Susan M , Abarca Katia , González Pablo A , Gálvez Nicolás M S , Soto Jorge A , Duarte Luisa F , Schultz Bárbara M , Pacheco Gaspar A , González Liliana A , Vázquez Yaneisi , Ríos Mariana , Melo-González Felipe , Rivera-Pérez Daniela , Iturriaga Carolina , Urzúa Marcela , Domínguez Angélica , Andrade Catalina A , Berríos-Rojas Roslye V , Canedo-Marroquín Gisela , Covián Camila , Moreno-Tapia Daniela , Saavedra Farides , Vallejos Omar P , Donato Paulina , Espinoza Pilar , Fuentes Daniela , González Marcela , Guzmán Paula , Muñoz Venturelli Paula , Pérez Carlos M , Potin Marcela , Rojas Álvaro , Fasce Rodrigo A , Fernández Jorge , Mora Judith , Ramírez Eugenio , Gaete-Argel Aracelly , Oyarzún-Arrau Aarón , Valiente-Echeverría Fernando , Soto-Rifo Ricardo , Weiskopf Daniela , Sette Alessandro , Zeng Gang , Meng Weining , González-Aramundiz José V , Kalergis Alexis M
Published: September 2021

Background

The development of effective vaccines against coronavirus disease 2019 is a global priority. CoronaVac is an inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine with promising safety and immunogenicity profiles. This article reports safety and immunogenicity results obtained for healthy Chilean adults aged ≥18 years in a phase 3 clinical trial.

Methods

Volunteers randomly received 2 doses of CoronaVac or placebo, separated by 2 weeks. A total of 434 volunteers were enrolled, 397 aged 18–59 years and 37 aged ≥60 years. Solicited and unsolicited adverse reactions were registered from all volunteers. Blood samples were obtained from a subset of volunteers and analyzed for humoral and cellular measures of immunogenicity.

Results

The primary adverse reaction in the 434 volunteers was pain at the injection site, with a higher incidence in the vaccine than in the placebo arm. Adverse reactions observed were mostly mild and local. No severe adverse events were reported. The humoral evaluation was performed on 81 volunteers. Seroconversion rates for specific anti-S1-receptor binding domain (RBD) immunoglobulin G (IgG) were 82.22% and 84.44% in the 18–59 year age group and 62.69% and 70.37% in the ≥60 year age group, 2 and 4 weeks after the second dose, respectively. A significant increase in circulating neutralizing antibodies was detected 2 and 4 weeks after the second dose. The cellular evaluation was performed on 47 volunteers. We detected a significant induction of T-cell responses characterized by the secretion of interferon-γ (IFN-γ) upon stimulation with Mega Pools of peptides from SARS-CoV-2.

Conclusions

Immunization with CoronaVac in a 0–14 schedule in Chilean adults aged ≥18 years is safe, induces anti-S1-RBD IgG with neutralizing capacity, activates T cells, and promotes the secretion of IFN-γ upon stimulation with SARS-CoV-2 antigens.
Is Coronavirus Disease 2019 (COVID-19) Less Deadly Now? Trends in In-Hospital Mortality Among Hospitalized COVID-19 Patients in the United States
Authors: Moon Rena C , Mackey Rachel H , Cao Zhun , Emont Seth , Schott Laura L , Gayle Julie A , Lipkin Craig , Rosenthal Ning A
Published: September 2021

After an initial decline from April through June 2020 (from 22.2% to 11.9%), adjusted in-hospital mortality in coronavirus disease 2019 (COVID-19) inpatients peaked twice and was significantly higher than June 2020 for subsequent months except in July and October 2020. Adjusted mortality trends differed across age groups between November 2020 and February 2021.
Spinal abscess in a patient with undiagnosed Gerbode defect: a case report
Authors: Liao Yuen Wei , Ensam Bode , Kodamanchile Aaditya , Duckett Simon
Published: September 2021

Background

Gerbode defect (GD) is a rare cardiac defect in which an abnormal communication occurs between the left ventricle and right atrium. The aetiology is usually congenital but acquired defects can occur.

Case summary

We report on a 47-year-old male with atrioventricular block prior to decompression of an epidural abscess extending from the skull base to the 7th thoracic vertebrae. Following positive blood cultures for Staphylococcus aureus, a transoesophageal echocardiogram performed revealed a small GD with associated endocarditis. In our case, the defect was small and there was no evidence of heart failure, there was little guidance or literature available on how to best manage our patient. A multidisciplinary decision was taken to treat the endocarditis medically and to not close the defect in the acute setting. He recovered well and did not suffer any further cardiac complications. A repeat transthoracic echocardiogram did not reveal any evidence of endocarditis.

Conclusion

Gerbode defects are rare but have been known to increase the risk of developing endocarditis. It is important to have a high clinical suspicion of endocarditis in patients with evidence of conduction disorders and systemic infection.
Variation among human populations in endometriosis and PCOS A test of the inverse comorbidity model
Authors: Crespi Bernard
Published: September 2021

Evidence linking endometriosis to low prenatal testosterone, and evidence that risk of polycystic ovary syndrome (PCOS) is associated with high prenatal testosterone, have motivated the hypothesis that endometriosis and PCOS exhibit inverse comorbidity. The inverse comorbidity hypothesis predicts that populations exhibiting higher prevalence of one disorder should show lower prevalence of the other. To test this prediction, data were compiled from the literature on the prevalence of endometriosis and PCOS, levels of serum testosterone in women during pregnancy and digit ratios as indicators of prenatal testosterone, in relation to variation in inferred or observed population ancestries. Published studies indicate that rates of endometriosis are highest in women from Asian populations, intermediate in women from European populations and lowest in women from African populations (i.e. with inferred or observed African ancestry); by contrast, rates of PCOS show evidence of being lowest in Asian women, intermediate in Europeans and highest in individuals from African populations. Women from African populations also show higher serum testosterone during pregnancy (which may increase PCOS risk, and decrease endometriosis risk, in daughters), and higher prenatal testosterone (as indicated by digit ratios), than European women. These results are subject to caveats involving ascertainment biases, socioeconomic, cultural and historical effects on diagnoses, data quality, uncertainties regarding the genetic and environmental bases of population differences and population variation in the causes and symptoms of PCOS and endometriosis. Despite such reservations, the findings provide convergent, preliminary support for the inverse comorbidity model, and they should motivate further tests of its predictions.

Lay Summary: Given that endometriosis risk and risk of polycystic ovary syndrome show evidence of having genetically, developmentally, and physiologically opposite causes, they should also show opposite patterns of prevalence within populations: where one is more common, the other should be more rare. This hypothesis is supported by data from studies of variation among populations in rates of endometriosis and PCOS and studies of variation among populations in levels of prenatal testosterone, which mediaterisks of both conditions.
Glycosylated apolipoprotein J in cardiac ischaemia: molecular processing and circulating levels in patients with acute ischaemic events
Authors: Cubedo Judit , Padró Teresa , Vilahur Gemma , Crea Filippo , Storey Robert F , Lopez Sendon Jose Luis , Kaski Juan Carlos , Sionis Alessandro , Sans-Rosello Jordi , Fernández-Peregrina Estefanía , Gallinat Alex , Badimon Lina
Published: September 2021

Aim

Using proteomics, we previously found that serum levels of glycosylated (Glyc) forms of apolipoprotein J (ApoJ), a cytoprotective and anti-oxidant protein, decrease in the early phase of acute myocardial infarction (AMI). We aimed to investigate: (i) ApoJ-Glyc intracellular distribution and secretion during ischaemia; (ii) the early changes in circulating ApoJ-Glyc during AMI; and (iii) associations between ApoJ-Glyc and residual ischaemic risk post-AMI.

Methods and results

Glycosylated apolipoprotein J was investigated in: (i) cells from different organ/tissue origin; (ii) a pig model of AMI; (iii) de novo AMI patients (n = 38) at admission within the first 6 h of chest pain onset and without troponin T elevation at presentation (early AMI); (iv) ST-elevation myocardial infarction patients (n = 212) who were followed up for 6 months; and (v) a control group without any overt cardiovascular disease (n = 144). Inducing simulated ischaemia in isolated cardiac cells resulted in an increased intracellular accumulation of non-glycosylated ApoJ forms. A significant decrease in ApoJ-Glyc circulating levels was seen 15 min after ischaemia onset in pigs. Glycosylated apolipoprotein J levels showed a 45% decrease in early AMI patients compared with non-ischaemic patients (P < 0.0001), discriminating the presence of the ischaemic event (area under the curve: 0.934; P < 0.0001). ST-elevation myocardial infarction patients with lower ApoJ-Glyc levels at admission showed a higher rate of recurrent ischaemic events and mortality after 6-month follow-up (P = 0.008).

Conclusions

These results indicate that ischaemia induces an intracellular accumulation of non-glycosylated ApoJ and a reduction in ApoJ-Glyc secretion. Glycosylated apolipoprotein J circulating levels are reduced very early after ischaemia onset. Its continuous decrease indicates a worsening in the evolution of the cardiac event, likely identifying patients with sustained ischaemia after AMI.