bluuebunny/crossref_metadata_2025 huggingface dataset:
Progenitor properties of type II supernovae: fitting to hydrodynamical models using Markov chain Monte Carlo methods
Authors: Martinez L. , Bersten M. C. , Anderson J. P. , González-Gaitán S. , Förster F. , Folatelli G.
Published: August 2020

Context.The progenitor and explosion properties of type II supernovae (SNe II) are fundamental to understanding the evolution of massive stars. Particular attention has been paid to the initial masses of their progenitors, but despite the efforts made, the range of initial masses is still uncertain. Direct imaging of progenitors in pre-explosion archival images suggests an upper initial mass cutoff of ∼18M⊙. However, this is in tension with previous studies in which progenitor masses inferred by light-curve modelling tend to favour high-mass solutions. Moreover, it has been argued that light-curve modelling alone cannot provide a unique solution for the progenitor and explosion properties of SNe II.

Aims.We develop a robust method which helps us to constrain the physical parameters of SNe II by simultaneously fitting their bolometric light curve and the evolution of the photospheric velocity to hydrodynamical models using statistical inference techniques.

Methods.We created pre-supernova red supergiant models using the stellar evolution code MESA, varying the initial progenitor mass. We then processed the explosion of these progenitors through hydrodynamical simulations, where we changed the explosion energy and the synthesised nickel mass together with its spatial distribution within the ejecta. We compared the results to observations using Markov chain Monte Carlo methods.

Results.We apply this method to a well-studied set of SNe with an observed progenitor in pre-explosion images and compare with results in the literature. Progenitor mass constraints are found to be consistent between our results and those derived by pre-SN imaging and the analysis of late-time spectral modelling.

Conclusions.We have developed a robust method to infer progenitor and explosion properties of SN II progenitors which is consistent with other methods in the literature. Our results show that hydrodynamical modelling can be used to accurately constrain the physical properties of SNe II. This study is the starting point for a further analysis of a large sample of hydrogen-rich SNe.
Local minimizers and gamma-convergence for nonlocal perimeters in Carnot groups
Authors: Carbotti Alessandro , Don Sebastiano , Pallara Diego , Pinamonti Andrea
Published: August 2020

We prove the local minimality of halfspaces in Carnot groups for a class of nonlocal functionals usually addressed as nonlocal perimeters. Moreover, in a class of Carnot groups in which the De Giorgi’s rectifiability theorem holds, we provide a lower bound for the Γ-liminf of the rescaled energy in terms of the horizontal perimeter.
Numerical upscaling for heterogeneous materials in fractured domains
Authors: Hellman Fredrik , Målqvist Axel , Wang Siyang
Published: August 2020

We consider numerical solution of elliptic problems with heterogeneous diffusion coefficients containing thin highly conductive structures. Such problems arise e.g. in fractured porous media, reinforced materials, and electric circuits. The main computational challenge is the high resolution needed to resolve the data variation. We propose a multiscale method that models the thin structures as interfaces and incorporate heterogeneities in corrected shape functions. The construction results in an accurate upscaled representation of the system that can be used to solve for several forcing functions or to simulate evolution problems in an efficient way. By introducing a novel interpolation operator, defining the fine scale of the problem, we prove exponential decay of the shape functions which allows for a sparse approximation of the upscaled representation. An a priori error bound is also derived for the proposed method together with numerical examples that verify the theoretical findings. Finally we present a numerical example to show how the technique can be applied to evolution problems.
SDO and LDO relaxation approaches to complex fractional quadratic optimization
Authors: Ashrafi Ali , Zare Arezu
Published: August 2020

This paper examines a complex fractional quadratic optimization problem subject to two quadratic constraints. The original problem is transformed into a parametric quadratic programming problem by the well-known classical Dinkelbach method. Then a semidefinite and Lagrangian dual optimization approaches are presented to solve the nonconvex parametric problem at each iteration of the bisection and generalized Newton algorithms. Finally, the numerical results demonstrate the effectiveness of the proposed approaches.
Trainieren für den Notfall
Authors: Quack Ivo
Published: August 2020

Niemand hofft, dass der Ernstfall jemals eintritt. Aber um dafür gewappnet zu sein, sollten Kliniken den Massenanfall von Verletzten regelmäßig trainieren. Im CNE Schwerpunkt stellen wir ein Notfallkonzept vor, um Schadensgroßereignisse – nach Unglücken, Katastrophen oder auch terroristischen Anschlägen – zu bewältigen.
Tragen von Ringdosimetern während einer OP
Authors: Rey Frank
Published: August 2020

Ab dieser Ausgabe starten wir einen neuen Service, den Hygieneticker. Hier erklärt unser Experte von der Caritas-Akademie Köln-Hohenlind alles rund um das Thema „Hygiene im OP“. Wenn Sie auch eine Frage an ihn haben, dann schreiben Sie eine E-Mail an ImOP@thieme.de. Im 1. Teil geht es darum, unter welchen Bedingungen Ringdosimeter von Operateuren während einer OP getragen werden können.
Exercise with End-expiratory Breath Holding Induces Large Increase in
Stroke Volume
Authors: Woorons Xavier , Lemaitre Frederic , Claessen Guido , Woorons Cloé , Vandewalle Henri
Published: August 2020

Eight well-trained male cyclists participated in two testing sessions each
including two sets of 10 cycle exercise bouts at 150% of maximal
aerobic power. In the first session, subjects performed the exercise bouts
with end-expiratory breath holding (EEBH) of maximal duration. Each exercise
bout started at the onset of EEBH and ended at its release (mean duration:
9.6±0.9 s; range: 8.6–11.1 s). At the second testing
session, subjects performed the exercise bouts (same duration as in the
first session) with normal breathing. Heart rate, left ventricular stroke
volume (LVSV), and cardiac output were continuously measured through
bio-impedancemetry. Data were analysed for the 4 s preceding and following
the end of each exercise bout. LVSV (peak values: 163±33 vs.
124±17 mL, p<0.01) was higher and heart rate lower both in
the end phase and in the early recovery of the exercise bouts with EEBH as
compared with exercise with normal breathing. Cardiac output was generally
not different between exercise conditions. This study showed that performing
maximal EEBH during high-intensity exercise led to a large increase in LVSV.
This phenomenon is likely explained by greater left ventricular filling as a
result of an augmented filling time and decreased right ventricular volume
at peak EEBH.
Koronararterien-Bypass
Authors: Zander Sabine , Opitz Eric
Published: August 2020

Fortgeschrittene koronare Herzerkrankungen können sowohl kardiologisch-interventionell als auch chirurgisch-invasiv behandelt werden. Unsere Autorin beschreibt eine chirurgisch relevante Therapieoption, die Koronararterien-Bypass-OP (englisch: coronary artery bypass grafting, kurz CABG) und gewährt dabei einen Blick hinter die Kulissen des Deutschen Herzzentrums Berlin (DHZB). Anhand des prüfungsrelevanten Erwartungshorizonts der Praxisanleiter des DHZB wird erläutert, wie mit körpereigenen Gefäßen die Engstelle im Herzkranzgefäß überbrückt und somit eine bessere Perfusion (Durchblutung) des Herzens wiederhergestellt wird.
Physiologie der Schmerzentstehung in der Peripherie
Authors: Eitner Annett , Richter Frank , Schaible Hans-Georg
Published: August 2020

Dieser Beitrag gibt einen Überblick über den Kenntnisstand zu den
Mechanismen der Schmerzentstehung im Gelenk. Er fokussiert sich auf den Vorgang
der Nozizeption in nozizeptiven Nervenfasern des Gelenks und stellt dar, wie
Krankheitsprozesse im Gelenk auf Nozizeptoren wirken. Während
Nozizeptoren im normalen Gelenk eine hohe Erregungsschwelle besitzen und nur
durch hochintensive Reize aktiviert werden, kommt es bei Gelenkerkrankungen
häufig zu einer Sensibilisierung dieser Nervenfasern, sodass sie bereits
auf leichte Reize (Bewegungen, Palpation) ansprechen und nach zentraler
Verarbeitung Schmerzempfindungen auslösen. Eine Sensibilisierung wird
meistens durch Entzündungsmediatoren ausgelöst, für die
die Nozizeptoren Rezeptoren besitzen. Werden Nervenfasern im Erkrankungsprozess
geschädigt, können neuropathische Schmerzmechanismen
hinzukommen. Chronische Gelenkerkrankungen sind durch entzündliche und
destruktive Prozesse charakterisiert. Sowohl bei primären Arthritiden
als auch bei Arthrosen sind entzündliche Prozesse für die
Sensibilisierung der Nozizeptoren verantwortlich. Dafür werden neben den
Prostaglandinen auch proinflammatorische Zytokine und der Nervenwachstumsfaktor
(NGF) verantwortlich gemacht, für die viele Nozizeptoren Rezeptoren
exprimieren. Demgemäß sind diese Moleküle auch Target
innovativer Schmerztherapien, z. B. die Gabe von Antikörpern
gegen NGF bei Arthrose. Besonders für die Neutralisation von TNF ist ein
direkt schmerzlindernder Effekt nachgewiesen, der aus der Unterbrechung von
nozizeptiven Vorgängen am Nozizeptor resultiert. Der direkte
pronozizeptive Effekt der Zytokine und Bindungsstellen für Fc-Fragmente
von Antikörpern an Nozizeptoren zeigen, dass Immunmechanismen auch
für die Schmerzentstehung große Bedeutung haben. Auch
destruktive Gelenkprozesse können Schmerzen verursachen. So kann bereits
die Osteoklastenaktivität im präklinischen Stadium einer
Arthritis Schmerzen verursachen, und nach Ausbruch der Arthritis tragen
Destruktionsprozesse zu Schmerzen bei. Inwieweit die Hemmung der
Osteoklastenaktivität Gelenkschmerzen lindert, wird derzeit erforscht.
Auch weitere neue Ansätze, peripher wirksame Opioide, Cannabinoide und
Ionenkanalblocker werden dargestellt. Schließlich geht der Beitrag auf
generelle/systemische Faktoren ein, die Krankheitsprozesse im Gelenk und
die Schmerzentstehung beeinflussen. Hier wird in erster Linie die Bedeutung des
Diabetes mellitus angesprochen. Diese Stoffwechselerkrankung stellt einen
Risikofaktor für die Entwicklung von Arthrosen dar, und sie
trägt zur Schmerzintensivierung bei. Dabei können
verstärkte Entzündungsprozesse und auch neuropathische
Schmerzkomponenten beteiligt sein.
Simple Synthesis of Dimethyl Nitrobenzhydrylphosphonates and Heteroarylnitroarylacetonitriles via Vicarious Nucleophilic Substitution (VNS) Reaction
Authors: Mąkosza Mieczysław , Bechcicka Małgorzata , Wojciechowski Krzysztof
Published: August 2020

Acetals of dimethyl phenyl- and heteroaryl-α-hydroxymethanephosphonates were deprotonated to generate carbanions, which enter the vicarious nucleophilic substitution (VNS) of hydrogen in aromatic nitro compounds to form 4-nitrobenzhydrylphosphonates and α-heteroaryl-4-nitrobenzylphosphonates. Similarly acetals of cyano­hydrins of heteroaromatic aldehydes (furfural and 2-formylthiophene) react to form heteroaryl 4-nitroarylacetonitriles. The anion of the hemiacetal of acetaldehyde is an efficient leaving group in the base-induced β-elimination step – the crucial step in the VNS reaction. The reaction selectively occurred at the para-position to the nitro group.
Recent Advances in Copper-Catalyzed Radical C–H Bond Activation Using N–F Reagents
Authors: Muñoz-Molina José María , Belderrain Tomás R. , Pérez Pedro J.
Published: August 2020

This Short Review is aimed at giving an update in the area of copper-catalyzed C–H functionalization involving nitrogen-centered radicals generated from substrates containing N–F bonds. These processes include intermolecular Csp3–H bond functionalization, remote Csp3–H bond functionalization via intramolecular hydrogen atom transfer (HAT), and Csp2–H bond functionalization, which might be of potential use in industrial applications in the future.

1 Introduction

2 Intermolecular Csp3–H Functionalization

3 Remote Csp3–H Functionalization

4 Csp2–H Functionalization

5 Conclusion
Recent Advances in Denitrogenative Reactions of Pyridotriazoles
Authors: Filippov Ilya P. , Titov Gleb D. , Rostovskii Nikolai V.
Published: August 2020

Diazo compounds display versatile reactivity and therefore are widely used in organic synthesis. Diazo compounds bearing a 2-pyridyl or a related azine moiety on the diazo carbon exist in the form of fused 1,2,3-triazoles. In this short review, we summarize the recent advances in denitrogenative reactions of [1,2,3]triazolo[1,5-a]pyridines (‘pyridotriazoles’) and related fused 1,2,3-triazoles. Over the past decade, there has been a surge of activity in this field, with novel denitrogenative reactions of pyridotriazoles induced by metal compounds, light, and Brønsted and Lewis acids having been devised. As a result, heterocyclic compounds and functionalized α-picolines as well as bio­active molecules have been synthesized. In the review, emphasis is also placed on the mechanisms of the new reactions.

1 Introduction

2 Ring-Chain Isomerization of Pyridotriazoles

3 Metal-Catalyzed Reactions

3.1 Rh(II) Catalysis

3.2 Rh(III) Catalysis

3.3 Cu Catalysis

3.4 Pd Catalysis

3.5 Catalysis by Other Metals

4 Metal-Free Reactions

5 Conclusion
Palladium-Catalyzed Cross-Coupling Reactions of 4-Tosyl­oxyquinazolines with Indoles: An Efficient Approach to 4-(1H-Indol-1-yl)quinazolines
Authors: Peng Yiyuan , Ye Xinglin , Huang Jian , Deng Zhihong , Yuan Jianjun
Published: August 2020

In this paper, exploration of our continuous interests on late-stage derivation of quinozaline core is described. A wide array of 4-(1H-indol-1-yl)quinazolines were obtained in good to excellent yields through palladium-catalyzed cross-coupling of 4-tosyloxyquinazolines with indole derivatives under mild reaction conditions.
Stability of 0.5% Glucose-Containing Balanced Electrolyte Solutions for Patients on Ketogenic Diets: A Laboratory Study
Authors: Heiderich Sebastian , Dennhardt Nils , Hartmann Hans , Kluger Gerhard Joseph , Sümpelmann Robert , Herberhold Thomas
Published: August 2020

Purpose Ketogenic diets (KDs) are used to treat epilepsies resistant to pharmacotherapy or some inborn errors of metabolism. For prolonged anesthesia, use of balanced electrolyte solutions (BESs) supplemented with 0.5% glucose has been advocated to maintain ketosis while preventing hypoglycemia. Unfortunately, there is no BES containing 0.5% glucose available from pharmacies. In a laboratory study, we investigated the physical and chemical stability of different BES mixtures containing 0.5% glucose.

Methods In total, six approaches were chosen to create a BES with 0.5% glucose: three different glucose-free BESs were supplemented with glucose. Additionally, commercially available BES containing 1% glucose was diluted with three different glucose-free BESs to obtain a solution containing 0.5% glucose. Turbidity, pH, electrical conductivity, and macroscopic appearance of these solutions were measured immediately, at 24 hours, and after 7 days, and were compared with the original BES.

Results Turbidity, pH, and electrical conductivity, as well as macroscopic appearance did not exceed the changes of the controls.

Conclusions No signs of incompatibility reactions could be observed in a 1-week time period. Our study supports the stability of the examined BES containing 0.5% glucose for prolonged anesthesia in patients on KD. Clinical studies are needed to evaluate if BES containing 0.5% glucose is superior in patients on KDs.
PV power output prediction from sky images using convolutional neural network: The comparison of sky-condition-specific sub-models and an end-to-end model
Authors: Nie Yuhao , Sun Yuchi , Chen Yuanlei , Orsini Rachel , Brandt Adam
Published: August 2020

Photovoltaics (PV), the primary use of solar energy, is growing rapidly. However, the variable output of PV under changing weather conditions may hinder the large-scale deployment of PV. In this study, we propose a two-stage classification-prediction framework to predict contemporaneous PV power output from sky images (a so-called “nowcast”), and compare it with an end-to-end convolution neural network (CNN). The proposed framework first classifies input images into different sky conditions and then the classified images are sent to specific sub-models for PV output prediction. Two types of classifiers are developed and compared: (1) a CNN-based classifier trained on clear sky index (CSI)-labeled sky images and (2) a physics-based non-parametric classifier based on a threshold of fractional cloudiness of sky images. Different numbers of classification categories are also examined. The results suggest that the cloudiness-based classifier is more suitable than the CSI-based classifier for the framework, and the 3-class classification (i.e., sunny, cloudy, overcast) is found to be the optimal choice. We then fine-tune the cloudiness threshold for the non-parametric classifier and tailor the architecture for each sky-condition-specific sub-model. Under the best design, the proposed framework can achieve a root mean squared error (RMSE) of 2.20 kW (relative to a 30 kW rated PV array) on the test set comprising 18 complete days (9 sunny, RMSE = 0.69 kW; 9 cloudy, RMSE = 3.06 kW). Compared with the end-to-end CNN baseline model, the overall prediction performance can be improved by 6% (7% in sunny and 6% in cloudy), with 6% fewer trainable parameters needed in the architecture.
Modeling the effects of scattering and absorption on the transmission of light in polycrystalline materials
Authors: Shachar M. H. , Uahengo G. , Penilla E. H. , Kodera Y. , Garay J. E.
Published: August 2020

As transparent polycrystalline materials become more important in optical applications, evaluation of their optical properties across a wide range of wavelengths (or frequencies) is crucial for device design. In-line transmission measurements are often used to assess the suitability of materials for a given optical application. We developed a model that describes reflection, scattering, and absorption losses that commonly affect transmission. The model demonstrates the effects that parameters such as absorption type (Lorentzian or Gaussian), scattering regime (Raleigh–Gans–Debye or Rayleigh), and optical path length have on transmission spectra. We also fit the model onto transmission data from three polycrystalline material systems: ruby, yttria stabilized zirconia, and terbia. Parameters extracted from these fits can be used to describe wavelength dependent transmission with one simple analytical expression. The fit can also be used to decouple absorption from scattering, allowing for the extraction of important properties such as absorption coefficients.
Realizations of rigid C*-tensor categories as bimodules over GJS C*-algebras
Authors: Hartglass Michael , Hernández Palomares Roberto
Published: August 2020

Given an arbitrary countably generated rigid C*-tensor category, we construct a fully faithful bi-involutive strong monoidal functor onto a subcategory of finitely generated projective bimodules over a simple, exact, separable, unital C*-algebra with a unique trace. The C*-algebras involved are built from the category using the Guionnet–Jones–Shlyakhtenko construction. Out of this category of Hilbert C*-bimodules, we construct a fully faithful bi-involutive strong monoidal functor into the category of bifinite spherical bimodules over an interpolated free group factor. The composite of these two functors recovers the functor constructed by Brothier, Hartglass, and Penneys.
Remnants of the disappearing critical point(s) in patchy fluids with distinct interaction patches
Authors: Tavares J. M. , Teixeira P. I. C.
Published: August 2020

We investigate the disappearance of the critical points of a model consisting of particles decorated with two patches of type A and a variable number (n) of patches of type B (2AnB patchy particles), in which only AA and AB bonds can form. This has been shown to exhibit a very rich phase behavior including one, two, or no liquid–vapor critical points, depending on two parameters: the ratio of the volumes available to each type of bond and the ratio of the bond strengths. We apply Wertheim’s theory in the limit of strong AA bonds to a lattice version of the model [Almarza et al., J. Chem. Phys. 137, 244902 (2012)] and show that the critical point does not always vanish at zero density and temperature, in contrast with results for particles decorated with only one type of patch. We uncover two remnants of the critical points—the lines of maximum and ideal compressibility—that survive even when no critical points are present.
Low Gilbert damping and high thermal stability of Ru-seeded L1-phase FePd perpendicular magnetic thin films at elevated temperatures
Authors: Zhang Delin , Huang Dingbin , Wu Ryan J. , Lattery Dustin , Liu Jinming , Wang Xinjun , Gopman Daniel B. , Mkhoyan K. Andre , Wang Jian-Ping , Wang Xiaojia
Published: August 2020

Bulk perpendicular magnetic anisotropy materials are proposed to be a promising candidate for next-generation ultrahigh density and ultralow energy-consumption spintronic devices. In this work, we experimentally investigate the structure, thermal stability, and magnetic properties of FePd thin films seeded by an Ru layer. An fcc-phase Ru layer induces the highly-ordered L10-phase FePd thin films with perpendicular magnetic anisotropy (Ku ∼10.1 Merg/cm3). The thermal stability of FePd samples is then studied through the annealing process. It is found that a Ku ∼6.8 Merg/cm3 can be obtained with an annealing temperature of 500 °C. In addition, the Gilbert damping constant α, an important parameter for switching current density, is determined as a function of the testing temperature. We observe that α increases from 0.006 to 0.009 for the as-deposited FePd sample and from 0.006 to 0.012 for the 400 °C-annealed FePd sample as the testing temperature changes from 25 °C to 150 °C. These results suggest that Ru-seeded FePd provides great potential in scaling perpendicular magnetic tunnel junctions below 10 nm for applications in ultralow energy-consumption spintronic devices.
Ytterbium-implanted photonic resonators based on thin film lithium niobate
Authors: Pak Dongmin , An Haechan , Nandi Arindam , Jiang Xiaodong , Xuan Yi , Hosseini Mahdi
Published: August 2020

We introduce our design, simulation, and fabrication for cm-long waveguides and micro-ring resonators based on fully-etched thin-film lithium niobate on insulator (LNOI) incorporated with rare earth ions. We implant ytterbium ions (Yb3+) into the crystalline host and study their optical properties at 4 K temperature. We measure an intrinsic optical quality factor of higher than 2×106 after postimplantation annealing. We characterize the photoluminescence spectrum, lifetime, and absorption of Yb3+ ions. Incorporation of rare earth ions into LNOI as a crystalline and nonlinear photonic element may enable the development of multi-functional quantum photonic devices capable of generating, transducing, manipulating, and storing of quantum optical information.
Pathway of orientational symmetry breaking in crystallization of short n-alkane droplets: A molecular dynamics study
Authors: Xu Dan , Lu Yuyuan , Luo Chuanfu
Published: August 2020

We carry out molecular dynamics simulations by using an all-atom model to study the nucleation and crystallization of n-alkane droplets under three-dimensional and quasi-two-dimensional conditions. We focus on the development of orientational order of chains from a random state to a neatly ordered one. Two new methods, the map of symmetry breaking and the information entropy of chain orientations, are introduced to characterize the emerge and remelting phenomena of a primary nucleus at the early stage of crystallization. Stepwise nucleation, as well as the surface induced nucleation, of large droplets is observed. We elucidate the kinetic process of the formation of a primary nucleus and the rearrangement of every single molecule involved in a primary nucleus. We found that density fluctuation and orientational preordering are coupled together and occur simultaneously in nucleation. Our results show the pathway of orientational symmetry breaking in the crystallization of n-alkane droplets that are heuristic for the deeper understanding of the crystallization in more complex molecules such as polymers.
Planar selective Leidenfrost propulsion without physically structured substrates or walls
Authors: Dodd Linzi E. , Agrawal Prashant , Geraldi Nicasio R. , Xu Ben B. , Wells Gary G. , Martin James , Newton Michael I. , McHale Glen , Wood David
Published: August 2020

The Leidenfrost effect allows droplets to be transported on a virtually frictionless layer of vapor above a superheated substrate. The substrates are normally topographically structured using subtractive techniques to produce saw-tooth, herringbone, and other patterns and bulk heated, leading to significant challenges in energy consumption and controlled operation. Here, we propose a planar lithographic approach to levitate and propel droplets using temperature profiles, which can be spatially patterned and controlled in time. We show that micro-patterned electrodes can be heated and provide control of the pressure profile and the vapor flow. Using these almost featureless planar substrates, we achieve self-directed motion of droplets, with velocities of approximately 30 mms−1, without topographically structuring the substrate or introducing physical walls. Our approach has the potential to be integrated into applications, such as digital microfluidics, where frictionless and contactless droplet transport may be advantageous.
Studying the size-selective precipitation of colloidal quantum dots by decomposing the excitation–emission matrix
Authors: Tovstun Sergey A. , Ivanchikhina Anastasia V. , Spirin Maxim G. , Martyanova Elena G. , Razumov Vladimir F.
Published: August 2020

The exciton peak in the excitation–emission matrix (EEM) of colloidal quantum dots implicitly contains information about inhomogeneous broadening and the photoluminescence (PL) and photoluminescence excitation (PLE) spectra of individual particles in the vicinity of the absorption onset. A numerical procedure for extracting this information has been developed and applied to the EEMs of polydisperse InP/ZnS core/shell colloidal quantum dots and their supernatant solutions obtained by partial precipitation with a non-solvent. The inhomogeneous broadenings obtained in this way have been converted by the sizing curve into particle-size distributions. These distributions have been found to be in agreement with the size-selective precipitation theory proposed recently. The homogeneous PL and PLE line shapes obtained by analyzing the EEMs were found to satisfy the Kennard–Stepanov relation, which is the first more or less direct evidence of its validity for colloidal quantum dots.
Suitability of Cu-substituted β-Mn2V2O7 and Mn-substituted β-Cu2V2O7 for photocatalytic water-splitting
Authors: Ninova Silviya , Strach Michal , Buonsanti Raffaella , Aschauer Ulrich
Published: August 2020

The pyrovanadates β-Mn2V2O7 and β-Cu2V2O7 were previously investigated as photoanode materials for water splitting. Neither of them, however, was found to be sufficiently active. In this work, we predict the properties of these two structurally similar pyrovanadates upon Cu/Mn substitution in their corresponding lattices via density functional theory calculations to explore the suitability of their band structure for water splitting and to assess their ease of synthesis. We predict that a concentration of up to 20% Cu and Mn into β-Mn2V2O7 and β-Cu2V2O7, respectively, leads to a narrowing of the bandgap, which, in the former case, is experimentally confirmed by UV–vis spectroscopy. Calculations in the intermediate composition range, however, yield nearly constant bandgaps. Moreover, we predict the materials with higher substitution levels to be increasingly difficult to synthesize, implying that low substitution levels are most relevant in terms of bandgaps and ease of synthesis.
Infrared spectroscopy of H+(CO)2 in the gas phase and in para-hydrogen matrices
Authors: Leicht Daniel , Rittgers Brandon M. , Douberly Gary E. , Wagner J. Philipp , McDonald David C. , Mauney Daniel T. , Tsuge Masashi , Lee Yuan-Pern , Duncan Michael A.
Published: August 2020

The H+(CO)2 and D+(CO)2 molecular ions were investigated by infrared spectroscopy in the gas phase and in para-hydrogen matrices. In the gas phase, ions were generated in a supersonic molecular beam by a pulsed electrical discharge. After extraction into a time-of-flight mass spectrometer, the ions were mass selected and probed by infrared laser photodissociation spectroscopy in the 700 cm−1–3500 cm−1 region. Spectra were measured using either argon or neon tagging, as well as tagging with an excess CO molecule. In solid para-hydrogen, ions were generated by electron bombardment of a mixture of CO and hydrogen, and absorption spectra were recorded in the 400 cm−1–4000 cm−1 region with a Fourier-transform infrared spectrometer. A comparison of the measured spectra with the predictions of anharmonic theory at the CCSD(T)/ANO1 level suggests that the predominant isomers formed by either argon tagging or para-hydrogen isolation are higher lying (+7.8 kcal mol−1), less symmetric isomers, and not the global minimum proton-bound dimer. Changing the formation environment or tagging strategy produces other non-centrosymmetric structures, but there is no spectroscopic evidence for the centrosymmetric proton-bound dimer. The formation of higher energy isomers may be caused by a kinetic effect, such as the binding of X (=Ar, Ne, or H2) to H+(CO) prior to the formation of X H+(CO)2. Regardless, there is a strong tendency to produce non-centrosymmetric structures in which HCO+ remains an intact core ion.
Non-autoregressive time-series methods for stable parametric reduced-order models
Authors: Maulik Romit , Lusch Bethany , Balaprakash Prasanna
Published: August 2020

Advection-dominated dynamical systems, characterized by partial differential equations, are found in applications ranging from weather forecasting to engineering design where accuracy and robustness are crucial. There has been significant interest in the use of techniques borrowed from machine learning to reduce the computational expense and/or improve the accuracy of predictions for these systems. These rely on the identification of a basis that reduces the dimensionality of the problem and the subsequent use of time series and sequential learning methods to forecast the evolution of the reduced state. Often, however, machine-learned predictions after reduced-basis projection are plagued by issues of stability stemming from incomplete capture of multiscale processes as well as due to error growth for long forecast durations. To address these issues, we have developed a non-autoregressive time series approach for predicting linear reduced-basis time histories of forward models. In particular, we demonstrate that non-autoregressive counterparts of sequential learning methods such as long short-term memory (LSTM) considerably improve the stability of machine-learned reduced-order models. We evaluate our approach on the inviscid shallow water equations and show that a non-autoregressive variant of the standard LSTM approach that is bidirectional in the principal component directions obtains the best accuracy for recreating the nonlinear dynamics of partial observations. Moreover—and critical for many applications of these surrogates—inference times are reduced by three orders of magnitude using our approach, compared with both the equation-based Galerkin projection method and the standard LSTM approach.
Plasmonics beyond noble metals: Exploiting phase and compositional changes for manipulating plasmonic performance
Authors: Gutiérrez Yael , Brown April S. , Moreno Fernando , Losurdo Maria
Published: August 2020

Reconfigurable plasmonics constitutes an exciting and challenging new horizon in nanophotonics. This blooming field aims at providing plasmonic nanostructures that present a dynamic and active plasmonic response that can be switched or manipulated by external stimuli to induce a controllable change in the optical properties. Most common plasmonic materials, such as the noble metals gold and silver, cannot deliver this type of behavior. Therefore, significant effort is being invested in developing alternative materials whose optical properties can be controllably modified to provide a reconfigurable plasmonic response. In this perspective, several materials including non-noble metals, transition metal oxides and nitrides, and chalcogenide compounds will be analyzed. The selected materials share interesting characteristics like low cost, good chemical and thermal stabilities, and CMOS compatibility while presenting a reconfigurable plasmonic response governed by different phase-change mechanisms.
Universal trends in human cough airflows at large distances
Authors: Prasanna Simha Padmanabha , Mohan Rao Prasanna Simha
Published: August 2020

Coughs are one of the primary means of transmission of diseases such as influenza and SARS-CoV-2 (COVID-19). Disease spreading occurs by the expulsion of pathogen containing aerosol droplets. Fine droplets can pass through layers of masks and are carried away by the exhaled airflow unlike larger droplets that settle down due to gravity. Hence, it is important to quantitatively assess the maximum distance of travel of typical human coughs with and without different types of masks. Even though near field data are available near the mouth, far field data are scarce. In this study, the schlieren method that is a highly sensitive, non-intrusive flow visualization technique is used. It can directly image weak density gradients produced by coughs. An assessment of different methods of covering the mouth while coughing is arrived at by using observations from high speed schlieren images. The effectiveness of coughing into the elbow is examined. The velocity of propagation of coughs and the distance of propagation with and without masks are quantified. It is also found that normalizing the distance–velocity profiles causes all the data to collapse onto a universal non-dimensional curve irrespective of the usage of different types of masks or test subjects. Visualization of cough flow fields and analysis of experimental data reveal that the flow physics is governed by the propagation of viscous vortex rings.
60
Fe deposition during the late Pleistocene and the Holocene echoes past supernova activity
Authors: Wallner A. , Feige J. , Fifield L. K. , Froehlich M. B. , Golser R. , Hotchkis M. A. C. , Koll D. , Leckenby G. , Martschini M. , Merchel S. , Panjkov S. , Pavetich S. , Rugel G. , Tims S. G.
Published: August 2020

Significance

Nearby supernova explosions shape the interstellar medium. Ejecta, containing fresh nucleosynthetic products, may traverse the solar system as a transient passage, or alternatively the solar system may traverse local clouds that may represent isolated remnants of supernova explosions. Such scenarios may modulate the galactic cosmic-ray flux intensity to which Earth is exposed. Varying conditions of the traversed interstellar medium could have impacts on climate and can be imprinted in the terrestrial geological record. Some radionuclides, such as
60
Fe, are not produced on Earth or within the solar system in significant quantities. Their existence in deep-sea sediments demonstrates recent production in close-by supernova explosions with a continued influx of
60
Fe until today.
Resolving the Dust Bowl paradox of grassland responses to extreme drought
Authors: Knapp Alan K. , Chen Anping , Griffin-Nolan Robert J. , Baur Lauren E. , Carroll Charles J.W. , Gray Jesse E. , Hoffman Ava M. , Li Xiran , Post Alison K. , Slette Ingrid J. , Collins Scott L. , Luo Yiqi , Smith Melinda D.
Published: August 2020

Significance

During the Dust Bowl drought, central US grasslands responded unexpectedly to a decade of hot, dry conditions. Grass species adapted to high temperatures with higher water use efficiency (C
4
grasses) decreased, while those preferring cooler climates (C
3
grasses) increased. We reproduced this surprising response by experimentally imposing extreme drought in two native grasslands. Analysis of historical climate records revealed that during extreme drought years, the proportion of annual precipitation that occurs during cooler months increases. This previously unidentified shift in seasonal precipitation patterns during extreme drought years provides a mechanism for C
3
grasses to increase despite overall hot, dry conditions. Thus, alterations in precipitation seasonality may be as important as reduced precipitation amount when forecasting ecosystem responses to extreme drought.
Biomass combustion produces ice-active minerals in biomass-burning aerosol and bottom ash
Authors: Jahn Leif G. , Polen Michael J. , Jahl Lydia G. , Brubaker Thomas A. , Somers Joshua , Sullivan Ryan C.
Published: August 2020

Significance

Ice-nucleating particles significantly alter cloud properties and lifetime, causing large but poorly constrained climate impacts. Biomass-burning aerosol emitted by wildfires is a major and growing source of atmospheric pollution. Prior work suggested that ice-nucleating particles can sometimes be emitted by biomass combustion, but the production and characteristics of these particles are poorly understood. Here we show that mineral phases are a significant ice-active component of both biomass-burning aerosol and ash particles. These mineral phases are derived from plant inorganic material that decomposes and reforms as ice-active minerals during combustion; they form more commonly from tall grass versus wood fuels. Aerosolized mineral and ash are now understood as a major source of the ice-nucleating particles in biomass-burning smoke.
Sequence-independent recognition of the amyloid structural motif by GFP protein family
Authors: Xu Sherry C. S. , LoRicco Josephine G. , Bishop Anthony C. , James Nathan A. , Huynh Welby H. , McCallum Scott A. , Roan Nadia R. , Makhatadze George I.
Published: August 2020

Significance

GFP and other related fluorescent proteins (FPs) are widely used in biological sciences. We discovered that FPs have an intrinsic high binding propensity for the core of amyloid fibrils. We have demonstrated this using over 10 different amyloid fibrils, characterized the binding interface, probed binding interface via mutagenesis, and performed a number of controls to show that binding is specific to amyloid structures and not to other nonamyloid fibrillar structures or soluble proteins with extended β-structure. This previously unrecognized functionality of FPs has two major implications: 1) It provides a tool to study amyloid structures, and 2) It suggests that caution should be taken when FPs are used as a fusion to visualize the cellular localization of proteins of interest.
Unique biodiversity in Arctic marine forests is shaped by diverse recolonization pathways and far northern glacial refugia
Authors: Bringloe Trevor T. , Verbruggen Heroen , Saunders Gary W.
Published: August 2020

Significance

Our work challenges the existing paradigm that marine Arctic ecosystems are depauperate extensions of southerly (temperate) communities established in the wake of recent glaciation, fundamentally changing how these systems should be viewed and interpreted. We forward hypotheses regarding the history of Arctic marine systems, particularly with regards to endemism being an integral feature of Arctic biomes, and present a firm framework for future evolutionary research in this system typically viewed as “ecologically immature.”
Elucidating the G″ overshoot in soft materials with a yield transition via a time-resolved experimental strain decomposition
Authors: Donley Gavin J. , Singh Piyush K. , Shetty Abhishek , Rogers Simon A.
Published: August 2020

Significance

The yielding transition in soft materials manifests macroscopically as a reversible transition from solid-like deformation to liquid-like flow under sufficiently large loading or deformation. Despite the ubiquity of materials that exhibit yielding, an understanding of the transition has remained elusive due to experimental limitations of the simple rheological tests typically used to study it. We present here a more thorough understanding of yielding, obtained via an iterative test protocol and analysis that allow for the separation of solid-like and liquid-like behaviors in the response of these materials. We show that yielding is a gradual transition, occurring to an increased extent as the deformation increases.
Testosterone and hippocampal trajectories mediate relationship of poverty to emotion dysregulation and depression
Authors: Barch Deanna M. , Shirtcliff Elizabeth A. , Elsayed Nourhan M. , Whalen Diana , Gilbert Kirsten , Vogel Alecia C. , Tillman Rebecca , Luby Joan L.
Published: August 2020

Significance

Experiencing poverty early in life is associated with continued risk for mental and physical health problems in childhood and adulthood. As such, it is important to understand the mechanisms by which poverty contributes to lasting risk for poor developmental outcomes. Here we use longitudinal prospectively acquired data starting in preschool to demonstrate that early poverty is associated with disruptions in developmental testosterone trajectories and hippocampal volume growth across school age and adolescent development, as well as with greater emotion dysregulation and depression in adolescence. Further, we provide evidence that such disruptions in hormonal and brain development are part of the pathway linking poverty to subsequent problems with emotion regulation and depression.
A noncanonical role of NOD-like receptor NLRP14 in PGCLC differentiation and spermatogenesis
Authors: Yin Yike , Cao Shiyu , Fu Huancheng , Fan Xueying , Xiong Jingfei , Huang Qiuyue , Liu Yu , Xie Kun , Meng Tie-Gang , Liu Yuliang , Tang Dan , Yang Tingting , Dong Biao , Qi Shiqian , Nie Ling , Zhang Huiyuan , Hu Hongbo , Xu Wenming , Li Fuping , Dai Lunzhi , Sun Qing-Yuan , Li Zhonghan
Published: August 2020

Significance

NOD-like receptors (NLRs) are traditionally recognized as key surveillance pattern recognition receptors (PRRs) during innate immune regulation. Several NLRs exhibit highly restricted expression in mammalian germline, where their physiological functions are largely unknown. Here we report that Nlrp14, an NLR specifically expressed in testis and ovary, plays a critical role in regulating germ cell differentiation and reproduction. Nlrp14 deficiency led to decreased primordial germ cell-like cell (PGCLC) differentiation in vitro and reproduction failure in both male and female mice in vivo. In the male mice, Nlrp14 knockout strongly compromised differentiation of spermatogonial stem cells and meiosis. Mechanistically, NLRP14 protected HSPA2 from proteasome-mediated degradation by recruiting BAG2, loss of which was further confirmed in a human mutation associated with male sterility.
The global value of water in agriculture
Authors: D’Odorico Paolo , Chiarelli Davide Danilo , Rosa Lorenzo , Bini Alfredo , Zilberman David , Rulli Maria Cristina
Published: August 2020

Significance

Water’s ability to generate value in irrigated agriculture remains poorly quantified at the global scale. The valuation of irrigation water is an important piece of information not only for agribusiness investors interested in the acquisition of land and water entitlements but also for farmers and rural communities that are negotiating with such investors. To make an informed decision about the acquisition or relinquishment of water rights or about investments in irrigation infrastructure there is a need for a better understanding of the value generated by irrigation water in agriculture using methods that rely on globally available data. This study provides a high-resolution global assessment of irrigation water value as a function of crop type and geographic location.
Huntingtin-interacting protein family members have a conserved pro-viral function from
Caenorhabditis elegans
to humans
Authors: Jiang Hongbing , Sandoval Del Prado Luis Enrique , Leung Christian , Wang David
Published: August 2020

Significance

Understanding host–virus interaction mechanisms is critical to identify novel drug targets for development of antiviral therapeutics. The
C. elegans
–Orsay virus infection system offers an innovative approach for discovering host factors required for virus infection. The
hipr-1
gene was determined to be essential in
C. elegans
for Orsay virus infection at an early stage of the virus life cycle. Studies of its orthologs in human cell culture determined that both HIP1 and HIP1R are important for Coxsackie B3 virus infection, highlighting the evolutionarily conserved role of HIP-family proteins in virus infection from nematodes to humans.
Dietary trends in herbivores from the Shungura Formation, southwestern Ethiopia
Authors: Negash Enquye W. , Alemseged Zeresenay , Bobe René , Grine Frederick , Sponheimer Matt , Wynn Jonathan G.
Published: August 2020

Significance

Studying the diet of fossil herbivores is a critical aspect of understanding past ecology. Here, we present carbon isotope data from the collective herbivore fauna in the Shungura Formation, Ethiopia, a key sequence for the study of mammalian evolution in eastern Africa. We document temporal patterns in the diet of nine mammalian herbivore families in the late Pliocene and early Pleistocene. The diet of herbivores has significantly changed in the last 3.5 Ma, and major dietary transitions are observed in several taxa around ∼2.7 Ma and then at ∼2.0 Ma. These patterns reflect response of the fauna to major ecological and environmental changes and provide a comparative framework for the study of hominin diet during this time.
Next-generation gene drive for population modification of the malaria vector mosquito,
Anopheles gambiae
Authors: Carballar-Lejarazú Rebeca , Ogaugwu Christian , Tushar Taylor , Kelsey Adam , Pham Thai Binh , Murphy Jazmin , Schmidt Hanno , Lee Yoosook , Lanzaro Gregory C. , James Anthony A.
Published: August 2020

Significance

Genetic systems for controlling transmission of vector-borne diseases are moving from discovery-stage demonstrations of proofs-of-principle to the next phases of development. A successful transition requires meeting safety and efficacy criteria defined in target product profiles. We show here that the Cas9/guide RNA-based gene-drive components of a genetically-engineered malaria mosquito vector,
Anopheles gambiae
, achieve key target product profile requirements for efficacy and performance. This system is designed to achieve mosquito population modification when coupled with genes encoding antiparasite effector molecules and result in stable and sustainable blocking of malaria parasite transmission.
A network-based explanation of why most COVID-19 infection curves are linear
Authors: Thurner Stefan , Klimek Peter , Hanel Rudolf
Published: August 2020

Significance

For many countries a plain-eye inspection of the COVID-19 infection curves reveals a remarkable linear growth over extended time periods. This observation is practically impossible to understand with traditional epidemiological models. These, to make them expressible in compact mathematical form, typically ignore the structure of real contact networks that are essential in the characteristic spreading dynamics of COVID-19. Here we show that by properly taking some relevant network features into account, linear growth can be naturally explained. Further, the effect of nonpharmaceutical interventions (NPIs), like national lockdowns, can be modeled with a remarkable degree of precision without fitting or fine-tuning of parameters.