bluuebunny/crossref_metadata_2025 huggingface dataset:
Large aperture scanning membrane phased array antenna for geosynchronous Earth orbit synthetic aperture radar applications
Authors: Xu Mingming , Zhang Qingjun , Zhu Yu , Zhao Bingji , Lv Zheng , Yu Weihua
Published: October 2019

A large aperture membrane phased array antenna with an array antenna and transmit/receive (T/R) modules is presented for geosynchronous Earth orbit synthetic aperture radar applications. Its scanning beams can cover ±8° with ignorable grating lobes within its visible area. By utilising the coplanar reintegration technique of multichips, compact and light‐weight T/R modules can be achieved. A scaled model is demonstrated and characterised experimentally. Measured results validate the feasibility and efficiency of the design method for the membrane phased array antenna.
Projection‐based state estimation using noisy destination
Authors: Zhou Chang , Li Keyi , Zhou Gongjian
Published: October 2019

The problem of state estimation with a destination constraint using the noisy prior information of the destination is investigated. With the utilisation of constraint information in estimation system, the estimation accuracy can be significantly enhanced. A projection‐based constrained state estimation method is proposed to address this problem. In this method, the unscented Kalman filter is employed to obtain the unconstrained estimation. The Taylor series expansion is adopted to deal with the non‐linearity of the destination constraint and the projection method is used to project the unconstraint estimate onto the constraint surface. Monte Carlo simulation results are presented to illustrate the effectiveness of the new approach.
Physical properties of terrestrial planets and water delivery in the habitable zone using N-body simulations with fragmentation
Authors: Dugaro A. , de Elía G. C. , Darriba L. A.
Published: October 2019

Aims. The goal of this research is to study how the fragmentation of planetary embryos can affect the physical and dynamical properties of terrestrial planets around solar-type stars. Our study focuses on the formation and evolution of planets and water delivery in the habitable zone (HZ). We distinguish class A and class B HZ planets, which have an accretion seed initially located inside and beyond the snow line, respectively.

Methods. We developed an N-body integrator that incorporates fragmentation and hit-and-run collisions, which is called D3 N-body code. From this, we performed 46 numerical simulations of planetary accretion in systems that host two gaseous giants similar to Jupiter and Saturn. We compared two sets of 23 N-body simulations, one of which includes a realistic collisional treatment and the other one models all impacts as perfect mergers.

Results. The final masses of the HZ planets formed in runs with fragmentation are about 15–20% lower than those obtained without fragmentation. As for the class A HZ planets, those formed in simulations without fragmentation experience very significant increases in mass with respect to their initial values, while the growth of those produced in runs with fragmentation is less relevant. We remark that the fragments play a secondary role in the masses of the class A HZ planets, providing less than 30% of their final values. In runs without fragmentation, the final fraction of water of the class A HZ planets keeps the initial value since they do not accrete water-rich embryos. In runs with fragmentation, the final fraction of water of such planets strongly depends on the model used to distribute the water after each collision. The class B HZ planets do not show significant differences concerning their final water contents in runs with and without fragmentation. From this, we find that the collisional fragmentation is not a barrier to the survival of water worlds in the HZ.
An examination of the effect of the TESS extended mission on southern hemisphere monotransits
Authors: Cooke Benjamin F. , Pollacco Don , Bayliss Daniel
Published: October 2019

Context. NASA recently announced an extended mission for TESS. As a result it is expected that the southern ecliptic hemisphere will be re-observed approximately two years after the initial survey.

Aims. We aim to explore how TESS re-observing the southern ecliptic hemisphere will impact the number and distribution of monotransits discovered during the first year of observations. This simulation will be able to be scaled to any future TESS re-observations.

Methods. We carry out an updated simulation of TESS detections in the southern ecliptic hemisphere. This simulation includes realistic Sector window-functions based on the first 11 sectors of SPOC 2 min SAP lightcurves. We then extend this simulation to cover the expected Year 4 of the mission when TESS will re-observe the southern ecliptic fields. For recovered monotransits we also look at the possibility of predicting the period based on the coverage in the TESS data.

Results. We find an updated prediction of 339 monotransits from the TESS Year 1 southern ecliptic hemisphere, and that approximately 80% of these systems (266/339) will transit again in the Year 4 observations. The Year 4 observations will also contribute new monotransits not seen in Year 1, resulting in a total of 149 monotransits from the combined Year 1 and Year 4 data sets. We find that 75% (189/266) of recovered Year 1 monotransits will only transit once in the Year 4 data set. For these systems we will be able to constrain possible periods, but period aliasing due to the large time gap between Year 1 and Year 4 observations means that the true period will remain unknown without further spectroscopic or photometric follow-up.
Impact d’entretiens pharmaceutiques en officine pour les patients refusant les médicaments génériques
Authors: Nickels Julia , Boltz Pierre-Yves , Feldman David , Dory Anne
Published: October 2019

Introduction : La substitution des médicaments princeps par leurs génériques a permis aux systèmes de santé de réaliser des économies financières substantielles. Si le taux de substitution des princeps par des génériques atteint 83 % en France, il n’est que de 79 % en Alsace en 2016. Objectif : Des entretiens pharmaceutiques ont été menés afin d’améliorer les connaissances des patients refusant les médicaments génériques et cette étude a pour objectif d’évaluer l’impact de ces entretiens. Méthodes : Un entretien pharmaceutique individuel a été proposé aux patients venant dans une pharmacie d’officine et refusant au moins un générique. L’entretien a consisté en un échange autour des génériques. Les connaissances des patients sur les génériques ont été évaluées, ainsi que leur satisfaction quant au déroulement de l’entretien. Résultats : Trente patients sur 78 ont accepté de participer aux entretiens. Les connaissances erronées portaient sur le principe actif identique, le dosage du principe actif, l’efficacité du principe actif. Dix-sept pourcent des patients réfractaires aux médicaments génériques changent de position après seulement un entretien pharmaceutique et ce changement persiste à 6 mois. Les résultats démontrent un entretien très apprécié par l’ensemble des patients. Discussion : Le comportement de certains patients peut être modifié de manière durable. Cependant, pour d’autres patients, d’autres interventions, comme des entretiens motivationnels ou des actions conjointes médecin et pharmacien, seront à initier pour améliorer le taux de substitution des génériques. Conclusion : Les entretiens pharmaceutiques visant à améliorer les connaissances des patients sur les génériques permettent à une minorité de patients de changer leurs perceptions et d’accepter les génériques de façon durable.
Aktuelle Standards in der Diagnostik und Therapie von peripheren T-Zell-Lymphomen
Authors: Hopfinger Georg , Staber Philipp
Published: October 2019

Was ist neu?

Neue WHO-Klassifikation 2016 für Lymphome und molekulare Marker Es erfolgte gegenüber der Version von 2008 eine genauere Definition einzelner Entitäten, wie z. B. dem anaplastischen großzelligen Lymphom (ALK). Darüber hinaus wird der Terminus des Enteropathie-assoziierten T-Zell-Lymphoms (EATCL, Typ 1) nunmehr für die mit einer Zöliakie assoziierten Form verwendet. Der Einsatz molekularer Marker mittels Next-Generation-Sequencing (NGS) ermöglicht einerseits eine bessere Differenzialdiagnostik; so ist z. B. das angioimmunoblastische Lymphom (AITL) durch das Vorliegen von TET2-, RHOA-, IDH2- und DNMT3A-Mutationen charakterisiert. Andererseits haben bestimmte Mutationen auch prognostische Bedeutung. Beim ALCL/ALK– ist der Nachweis eines DUSP22 / IRF4-Rearrangements mit einer besseren, der Nachweis von TP63 mit einer schlechteren Prognose assoziiert.

Klinisches Bild und Prognose Neben sog. B-Symptomatik und nodaler Manifestation können auch extranodale Manifestationen wie Hautinfiltrate in bis zu 20 % beobachtet werden. Als Zeichen eines dysregulierten Immunsystems können beim AITL eine polyklonale Hypergammaglobulinämie, Coombs-positive hämolytische Anämie und Immundefizienz auftreten.

Fortschritte in der Therapie Durch Kombination des Immunkonjugats Brentuximab-Vedotin (BV) mit Chemotherapie konnte erstmals ein positiver Effekt auf krankheitsfreies (PFS) und Gesamtüberleben (OS) bei CD30+-PTCL gezeigt werden.

Ausblick Gegenwärtig werden neue Therapieansätze, z. B. mit der demethylierenden Substanz 5-Azacytidin bei AITL und PTCL mit einem T-Follikel-Helper-Type (TFH), geprüft.
Effects of Relative Drop Heights of Drop Jump Biomechanics in Male Volleyball Players
Authors: Peng Hsien-Te , Song Chen-Yi , Wallace Brian J. , Kernozek Thomas W. , Wang Min-Hsien , Wang Yu-Han
Published: October 2019

Previous cross-sectional studies have reported that higher drop heights do not always result in improved performance, and may increase injury risk during drop jumps (DJ). The purpose of this study was to analyze the kinematics and kinetics during the DJ in order to determine the relative drop height that maximize performance without exposing the lower extremity joints to unnecessary loads. Twenty male Division I college volleyball players volunteered. Data were collected using 11 infrared cameras and two force platforms. Participants performed three maximal effort countermovement jumps (CMJ). Subsequently, 50, 75, 100, 125, and 150% CMJ height (CMJH) was used to scale their relative drop height for three DJ trials per height. There was a significant increase in the landing phase impulse when the drop height exceeded 100%CMJH (p<0.05). At 125% and 150%CMJH, the negative work of knee and ankle significantly increased. The incoming velocity, kinetic energy, landing depth, maximum ground reaction force, landing impulse and power absorption of knee and ankle all increased with drop height (p<0.05). DJ height and reactive strength index following the drop landing were not statistically different between any of the drop heights (p>0.05). 50% to 100%CMJH may be the appropriate individual relative drop height for the DJ.
Umfrage: Was hat Sie dazu bewogen, die Gastroenterologie als Fachgebiet auszuwählen?
Authors: Hann Alexander , Lammert Frank , Walter Steffen , Jansen Petra Lynen ,   für die Kommission Lehre und Studium der DGVS,   Kommission Lehre und Studium der DGVS
Published: October 2019

Einleitung Die gezielte Förderung des ärztlichen Nachwuchses ist in der Gastroenterologie unerlässlich. Ziel dieser Studie war es, Faktoren zu identifizieren, die Mitglieder der Deutschen Gesellschaft für Gastroenterologie, Verdauungs- und Stoffwechselkrankheiten (DGVS) dazu bewogen haben, die Gastroenterologie als Fachgebiet auszuwählen.

Methoden Die Umfrage wurde online an alle DGVS-Mitglieder versendet. Es wurden folgende Faktoren beurteilt: frühester Entschlusszeitpunkt für das Fachgebiet Gastroenterologie, bedeutsame Mentoren und Vorbilder, beeinflussende Studieninhalte, die Rolle der Doktorarbeit und weitere Aspekte der Gastroenterologie. Ausgewertet wurden die Ergebnisse aller Teilnehmer mit Subgruppenanalysen in Bezug auf Berufserfahrung (≤ 8, 9–29, ≥ 30 Jahre) und Tätigkeitsort (Universitätsklinikum, kommunales Krankenhaus, gastroenterologische Schwerpunktpraxis).

Ergebnisse Es wurden 1358 Fragebogen ausgefüllt (Rücklaufquote 24,2 %). Befragte mit ≤ 8 Jahren Berufserfahrung haben sich zu 62,5 % bereits im Rahmen des Studiums entschieden, sich als Gastroenterologe/-in zu spezialisieren; bei Befragten mit ≥ 9 Berufserfahrungsjahren waren dies 37,1 % (p < 0,001). Oberärzte/-innen werden mit 40,8 % Nennung als die bedeutsamsten Vorbilder/Mentoren für die Wahl des Fachs genannt. Bei 42,8 % der Teilnehmenden hatte der Doktorvater bzw. die Doktormutter im Falle einer gastroenterologischen Promotion diese Rolle inne. Praktische Übungen wie Sonografie spielten bei 42,2 % der Teilnehmenden eine wesentliche Rolle bei den Studieninhalten. Die interventionelle Medizin in Form der Endoskopie und die Vielfältigkeit des Fachs innerhalb der Inneren Medizin wurden als weitere wichtigste Faktoren eingestuft.

Schlussfolgerungen Der Entschluss, die Gastroenterologie als Spezialgebiet zu wählen, fällt größtenteils bereits im Studium. Oberärzte/-innen spielen als Mentoren eine entscheidende Rolle. Besonders praktische Studieninhalte wie Sonografie, aber auch Endoskopie sind bedeutsame Einflussfaktoren für die Wahl des Fachs.
The tail wagging the dog: positive attitude towards livestock guarding dogs do not mitigate pastoralists’ opinions of wolves or grizzly bears
Authors: Kinka Daniel , Young Julie K.
Published: October 2019

While the re-establishment of grizzly bears (Ursus arctos) and wolves (Canis lupus) in the American West marks a success for conservation, it has been contentious among pastoralists. Coincidentally, livestock guarding dogs (LGDs;Canis familiaris) have been widely adopted by producers of domestic sheep (Ovis aries) in the United States to mitigate livestock depredation by wild carnivores. We surveyed pastoralists to measure how experience with and attitudes towards LGDs related to attitudes towards livestock predators, and found positive responses regarding LGDs and negative responses regarding wolves and grizzly bears. The more respondents agreed that LGDs reduce the need for lethal management (p < 0.01) and prevent the spread of disease (p < 0.05), the more positive their opinion of wolves in the wild. Regarding wolves and livestock, respondents who disagreed with the statements that “LGDs do more harm than good” (p < 0.05) or “reduce the need for lethal management” (p < 0.001), were more likely to express more negative opinions of wolves. While results pertaining to a reduced need for lethal management may suggest LGDs have some ability to increase tolerance for wolves, the causal order of these effects is difficult to discern. A more positive attitude for wolves to begin with may predict more optimistic attitudes about the capacity of LGDs to reduce human–wildlife conflict. We found almost no support for the opinion that LGDs do more harm than good, even though attitudes towards wolves were generally negative. Respondents with up to 10 years’ experience using LGDs had more negative attitudes towards grizzly bears (p < 0.01) and respondents with more than 10 years’ experience using LGDs had the most negative attitudes towards grizzly bears (p < 0.001). Thus, while experience was the greatest predictor of attitudes towards grizzly bears, attitudes towards wolves were most correlated with the belief that LGDs offset the need for lethal management of carnivores. These results suggest that LGD use in the United States does not seem to have resulted in more positive attitudes about livestock predators amongst pastoralists.
Uncertainty of financial time series based on discrete fractional cumulative residual entropy
Authors: Zhang Boyi , Shang Pengjian
Published: October 2019

Cumulative residual entropy (CRE) is a measure of uncertainty and departs from other entropy in that it is established on cumulative residual distribution function instead of density function. In this paper, we prove some important properties of discrete CRE and propose fractional multiscale cumulative residual entropy (FMCRE) as a function of fractional order α, which combines CRE with fractional calculus, probability of permutation ordinal patterns, and multiscale to overcome the limitation of CRE. After adding amplitude information through weighted permutation ordinal patterns, we get fractional weighted multiscale cumulative residual entropy (FWMCRE). FMCRE and FWMCRE extend CRE into a continuous family and can be used in more situations with a suitable parameter. Moreover, they can capture long-range phenomena more clearly and have higher sensitivity to the signal evolution. Results from simulated data verify that FMCRE and FWMCRE can identify time series accurately and have immunity to noise. We confirm that the length of time series has little effect on the accuracy of distinguishing data, and even short series can get results exactly. Finally, we apply FMCRE and FWMCRE on stock data and confirm that they can be used as metrics to measure uncertainty of the system as well as distinguishing signals. FWMCRE can also track changes in stock markets and whether adding amplitude information must be decided by the characteristics of data.
Resistively loaded monocone for pulse electric field calibrations
Authors: Jiang Tingyong , Ning Hui , Zhou Heng , Wang Xiaojia
Published: October 2019

A novel resistive loaded monocone is proposed to extend the time window for pulse electric field calibrations. A resistor array is loaded at the end of a monocone to reduce end reflections. A simulation software was used to optimize the resistive load. Simulations revealed that the optimized loading method can better reduce end reflections compared with conventional approaches. The return loss (S11) was reduced to −18 dB for frequencies from DC to 1 GHz, and the end voltage reflectivity was reduced from 0.14 to 0.05 when the width of the exciting Gaussian pulse was 1 ns. An experimental setup was constructed to verify the optimization scheme and demonstrate the practicality of the design. The measured results of the proposed loaded monocone agreed well with the simulations and are promising for potential applications in future pulsed electromagnetic standard facilities.
Non-integrable dimer models: Universality and scaling relations
Authors: Giuliani Alessandro , Toninelli Fabio Lucio
Published: October 2019

In the last few years, the methods of constructive fermionic renormalization group have been successfully applied to the study of the scaling limit of several two-dimensional statistical mechanics models at the critical point, including weakly nonintegrable 2D Ising models, Ashkin-Teller, 8-Vertex, and close-packed interacting dimer models. In this note, we focus on the illustrative example of the interacting dimer model and review some of the universality results derived in this context. In particular, we discuss the massless Gaussian free field (GFF) behavior of the height fluctuations. It turns out that GFF behavior is connected with a remarkable identity (“Haldane” or “Kadanoff relation”) between an amplitude and an anomalous critical exponent, characterizing the large distance behavior of the dimer-dimer correlations.
On the origin of the enhancement of defect related visible emission in annealed ZnO micropods
Authors: Gokarna Anisha , Aad Roy , Zhou Junze , Nomenyo Komla , Lusson Alain , Miska Patrice , Lerondel Gilles
Published: October 2019

We report an in-depth analysis of ZnO micropods emission. A strong correlation between defect and interband emissions is observed. ZnO micropods were grown using low-temperature chemical bath deposition (CBD). ZnO micropods exhibited perfectly-crystalline hexagonally-shaped facets with various numbers of branches. Raman studies showed that ZnO micropods contained trapped zinc hydroxide (OH) and imidogen (NH) defects that originate from the precursor solution used in the CBD technique. These defects were evacuated by thermal annealing, leading to the recrystallization in the volume of the micropods and the formation of structural defects at their surface, as attested by scanning electron microscopy and X-ray diffraction. More importantly, the thermal annealing was accompanied by a breakdown of the NH defects, which resulted in a nitrogen doping of the ZnO micropods. The structural changes as well as the nitrogen doping resulted in a drastic change in the photoluminescence (PL) spectrum of the ZnO micropods that exhibited a stronger free exciton UV emission as well as a stronger visible (white) emission. An in-depth low-temperature PL study of both UV and visible emission reveals a strong interplay between the structural-defect bound excitonic UV emission (Y-band) and the deep donor (visible) emission, which suggests a rather complex emission mechanism involving an efficient nonradiative energy transfer between the Y-band states and defect states leading to the enhanced visible emission of ZnO micropods after high temperature annealing.
Optimization of in vivo murine X-ray dark-field computed tomography
Authors: Umkehrer Stephan , Birnbacher Lorenz , Burkhardt Rico , von Teuffenbach Maximilian , Yildirim Ali Önder , Pfeiffer Daniela , Herzen Julia , Pfeiffer Franz
Published: October 2019

Grating-based dark-field interferometry can be realized with lab-based, low-brilliance X-ray sources and provides scattering information of sample structures below the detector pixel size. This unique property allows promising medical imaging applications, especially for lung diseases. Structural damage in lung tissue caused by pulmonary emphysema or pulmonary carcinoma could be observed in radiographs by changes in the dark-field signal with high sensitivity at early stages, in contrast to the conventional absorption signal. Currently, the standard for diagnosis in the clinical routine of pulmonary diseases is absorption computed tomography (CT). The assessment of a larger number of samples with in vivo dark-field CT is limited by the rather long scan times, the order of 2 h, that are required to obtain sufficient CT data quality. In this work, a prototype in vivo, small-animal, dark-field CT is optimized with respect to CT measurements with the following: usage of an iterative reconstruction algorithm for the reduction of undersampling artifacts, a rearranged data acquisition scheme with reduced amount of dead time, and thinned gratings and curved grating geometry for more efficient utilization of the 37 kV X-ray flux. The device performance is evaluated with noise-effective dose measurements, image contrast-to-noise ratio, interferometry visibility across the field-of-view, and a reduced measurement time of 40 min with a deposited dose of 85 mGy.
A Lorenz-type attractor in a piecewise-smooth system: Rigorous results
Authors: Belykh Vladimir N. , Barabash Nikita V. , Belykh Igor V.
Published: October 2019

Chaotic attractors appear in various physical and biological models; however, rigorous proofs of their existence and bifurcations are rare. In this paper, we construct a simple piecewise-smooth model which switches between three three-dimensional linear systems that yield a singular hyperbolic attractor whose structure and bifurcations are similar to those of the celebrated Lorenz attractor. Due to integrability of the linear systems composing the model, we derive a Poincaré return map to rigorously prove the existence of the Lorenz-type attractor and explicitly characterize bifurcations that lead to its birth, structural changes, and disappearance. In particular, we analytically calculate a bifurcation curve explicit in the model’s parameters that corresponds to the formation of homoclinic orbits of a saddle, often referred to as a “homoclinic butterfly.” We explicitly indicate the system’s parameters that yield a bifurcation of two heteroclinic orbits connecting the saddle fixed point and two symmetrical saddle periodic orbits that gives birth to the chaotic attractor as in the Lorenz system. These analytical tasks are out of reach for the original nonintegrable Lorenz system. Our approach to designing piecewise-smooth dynamical systems with a predefined chaotic attractor and exact solutions may open the door to the synthesis and rigorous analysis of hyperbolic attractors.
Quantum dynamics of vibration-assisted excitation energy transfer in phycobiliprotein light-harvesting complex
Authors: Kosenkov Yana Kholod , Kosenkov Dmitri
Published: October 2019

Phycobiliprotein is a light-harvesting complex containing linear tetrapyrrole bilin pigments that are responsible for absorption and funneling the sun’s energy in cryptophytes algae. In particular, the protein structure determines relative positions and orientations of the pigments and thus controls energy transfer pathways. The present research reveals the impact of molecular vibrations (in the 850–2700 cm−1 region) on excitation energy transfer in phycobiliprotein. The analysis of the excitation energy transfer pathways indicates a possibility of the coherent mechanism of energy transfer (delocalization) in central dihydrobiliverdin pigments and incoherent vibration-assisted energy transfer to peripheral phycocyanobilin pigments at a sub-picosecond time scale. A computational approach that enables modeling the dynamics of the excitation energy transfer with the quantum master equation formalism employing Huang-Rhys factors to describe electronic-vibrational coupling has been developed. The computational methodology has been implemented in PyFREC software.
Curl-free magnetic fields for stellarator optimization
Authors: Boozer Allen H.
Published: October 2019

This paper describes a new and efficient method of defining an annular region of a curl-free magnetic field with specific physics and coil properties that can be used in stellarator design. Three statements define the importance: (1) Codes can follow an optimized curl-free initial state to a final full-pressure equilibrium. The large size of the optimization space of stellarators, approximately 50 externally produced distributions of magnetic field, makes success in finding a global optimum largely determined by the starting point. (2) The design of a stellarator is actually improved when the central region of the plasma has rapid transport with the confinement provided by a surrounding annulus of magnetic surfaces with low transport. (3) The stellarator is unique among all fusion concepts, inertial as well as magnetic, in not using the plasma itself to provide an essential part of its confinement concept. This permits reliable computational design, which opens a path to faster, cheaper, and more certain achievement of fusion energy.
Dopant solubility and charge compensation in La-doped SrSnO3 films
Authors: Truttmann Tristan , Prakash Abhinav , Yue Jin , Mates Thomas E. , Jalan Bharat
Published: October 2019

We investigate lanthanum (La) as an n-type dopant in the strain-stabilized tetragonal phase of SrSnO3 grown on GdScO3 (110) using a radical-based hybrid molecular beam epitaxy approach. Fully coherent, epitaxial films with an atomically smooth film surface were obtained irrespective of doping density. By combining secondary ion mass spectroscopy and Hall measurements, we demonstrate that each La atom contributes one free electron to the film, confirming that it occupies the Sr site in SrSnO3 and that it is completely activated. Carrier density exceeding 1 × 1020 cm−3 was achieved in La-doped SrSnO3 films, which is in excellent agreement with the dopant-solubility limit predicted by density functional theory calculations. A record-high room-temperature mobility of 70 cm2 V−1 s−1 at 1 × 1020 cm−3 was obtained in a 12 nm La-doped SrSnO3 film, making this the thinnest perovskite oxide semiconductor with electron mobility exceeding 25 cm2 V−1 s−1 at room temperature. We discuss the structure-dopant-transport property relationships, providing essential knowledge for the design of electronic devices using these materials.
Correction of coarse-graining errors by a two-level method: Application to the Asakura-Oosawa model
Authors: Kobayashi Hideki , Rohrbach Paul B. , Scheichl Robert , Wilding Nigel B. , Jack Robert L.
Published: October 2019

We present a method that exploits self-consistent simulation of coarse-grained and fine-grained models in order to analyze properties of physical systems. The method uses the coarse-grained model to obtain a first estimate of the quantity of interest, before computing a correction by analyzing properties of the fine system. We illustrate the method by applying it to the Asakura-Oosawa model of colloid-polymer mixtures. We show that the liquid-vapor critical point in that system is affected by three-body interactions which are neglected in the corresponding coarse-grained model. We analyze the size of this effect and the nature of the three-body interactions. We also analyze the accuracy of the method as a function of the associated computational effort.
Interfacial free energy of a liquid-solid interface: Its change with curvature
Authors: Montero de Hijes P. , Espinosa Jorge R. , Sanz Eduardo , Vega Carlos
Published: October 2019

We analyze the changes in the interfacial free energy between a spherical solid cluster and a fluid due to the change of the radius of the solid. Interfacial free energies from nucleation studies using the seeding technique for four different systems, being hard spheres, Lennard-Jones, and two models of water (mW and TIP4P/ICE), were plotted as a function of the inverse of the radius of the solid cluster. In all cases, the interfacial free energy was a linear function of the inverse of the radius of the solid cluster and this is consistent with Tolman’s equation. This linear behavior is shown not only in isotherms but also along isobars. The effect of curvature on the interfacial free energy is more pronounced in water, followed by hard spheres, and smaller for Lennard-Jones particles. We show that it is possible to estimate nucleation rates of Lennard-Jones particles at different pressures by using information from simple NpT simulations and taking into account the variation of the interfacial free energy with the radius of the solid cluster. Neglecting the effects of the radius on the interfacial free energy (capillarity approximation) leads to incorrect values of the nucleation rate. For the Lennard-Jones system, the homogeneous nucleation curve is not parallel to the melting curve as was found for water in previous work. This is due to the increase in the interfacial free energy along the coexistence curve as the pressure increases. This work presents a simple and relatively straightforward way to approximately estimate nucleation rates.
Exciton relaxation in carbon nanotubes via electronic-to-vibrational energy transfer
Authors: Velizhanin Kirill A.
Published: October 2019

Covalent functionalization of semiconducting single-wall carbon nanotubes (CNTs) introduces new photoluminescent emitting states. These states are spatially localized around functionalization sites and strongly red-shifted relative to the emission commonly observed from the CNT band-edge exciton state. A particularly important feature of these localized exciton states is that because the exciton is no longer free to diffusively sample photoluminescent quenching sites along the CNT length, its lifetime is significantly extended. We have recently demonstrated that an important relaxation channel of such localized excitons is the electronic-to-vibrational energy transfer (EVET). This process is analogous to the Förster resonance energy transfer except the final state of this process is not electronically, but vibrationally excited molecules of the surrounding medium (e.g., solvent). In this work, we develop a theory of EVET for a nanostructure of arbitrary shape and apply it to the specific case of EVET-mediated relaxation of defect-localized excitons in a covalently functionalized CNT. The resulting EVET relaxation times are in good agreement with experimental data.
The electron canonical battery effect in magnetic reconnection: Completion of the electron canonical vorticity framework
Authors: Yoon Young Dae , Bellan Paul M.
Published: October 2019

A widespread practice in studying magnetic reconnection is to examine the electron momentum equation. Here, we present an alternative, ab initio framework that examines the motion of the electron canonical vorticity, which is the curl of the electron canonical momentum. The competition between just two terms—the convective term and the electron canonical battery term—determines the dynamics of electron canonical vorticity and equivalently the electron physics down to first principles. To demonstrate the power of this approach, the growth, saturation, stability, and morphology of the electron diffusion region are explained within the electron canonical vorticity framework. The framework provides a clear distinction between reconnection models where the frozen-in property of the magnetic field is violated by electron inertia and by pressure tensor effects such as electron viscosity.
Study of spectral and temporal parameters of superradiance on molecular nitrogen ions in air filament
Authors: Zyatikov I.A. , Ivanov N.G. , Losev V.F. , Prokop’ev V.E.
Published: October 2019

We report the results of a high temporal resolution study on the formation of superradiance (SR) in plasma on the first negative system of molecular nitrogen ions in plasma of an air filament. The filament is formed by a femtosecond laser pulse with a wavelength of λ = 950 nm. For the first time, the actual SR pulse duration at λ = 428 nm is measured, which constitutes 1.15 ps (FWHM). According to measurements of a spectral width equal to 0.26 nm, this pulse duration is close to transform-limited (1 ps). It is shown that there is a delay by 6 ps in the SR pulse maximum relative to the pump.
Broadband lightweight flat lenses for long-wave infrared imaging
Authors: Meem Monjurul , Banerji Sourangsu , Majumder Apratim , Vasquez Fernando Guevara , Sensale-Rodriguez Berardi , Menon Rajesh
Published: October 2019

Significance

We demonstrate, with simulations corroborated by experiments, that broadband long-wave infrared (LWIR) imaging is possible with a single flat lens with a thickness of 10 μm and a weight that is over 100 times less than conventional refractive optics. Reducing the weight and thickness of LWIR optics is crucial for increasing the range of camera-carrying drones as well as for reducing head and neck injuries among camera-borne soldiers. The technology discussed herein will be extremely useful not only to optics specialists but also to camera designers and users in general.
Ancient Maya wetland fields revealed under tropical forest canopy from laser scanning and multiproxy evidence
Authors: Beach Timothy , Luzzadder-Beach Sheryl , Krause Samantha , Guderjan Tom , Valdez Fred , Fernandez-Diaz Juan Carlos , Eshleman Sara , Doyle Colin
Published: October 2019

Significance

Understanding agricultural subsistence is vital for understanding past complex societies. Lidar data are indicating widespread ancient Maya infrastructure. Wetland agriculture was crucial to ancient cultures, but no previous study coupled lidar with multiproxy evidence to demonstrate the extent and uses of Maya wetland fields. We conducted a lidar survey around wetlands that multiple use proxies established were ancient Maya polycultural systems. Lidar indicated the Birds of Paradise (BOP) wetland field complex was five times larger than we had previously mapped and identified an even larger wetland agroecosystem. We ground-verified the BOP fields through excavations and dating, creating a study to couple these multiproxy data with lidar, thereby demonstrating widespread ancient Maya wetland agroecosystems.
Ribosome collisions alter frameshifting at translational reprogramming motifs in bacterial mRNAs
Authors: Smith Angela M. , Costello Michael S. , Kettring Andrew H. , Wingo Robert J. , Moore Sean D.
Published: October 2019

Significance

Ribosomes move along mRNAs in 3-nucleotide steps as they interpret codons that specify which amino acid is required at each position in the protein. There are multiple examples of genes with DNA sequences that do not match the produced proteins because ribosomes move to a new reading frame in the message before finishing translation (so-called frameshifting). This report shows that, when ribosomes stall at mRNA regions prone to cause frameshifting events, trailing ribosomes that collide with them can significantly change the outcome and potentially regulate protein production. This work highlights the principle that biological macromolecules do not function in isolation, and it provides an example of how physical interactions between neighboring complexes can be used to augment their performance.
Cell-type–specific transcriptome and histone modification dynamics during cellular reprogramming in the Arabidopsis stomatal lineage
Authors: Lee Laura R. , Wengier Diego L. , Bergmann Dominique C.
Published: October 2019

Plant cells maintain remarkable developmental plasticity, allowing them to clonally reproduce and to repair tissues following wounding; yet plant cells normally stably maintain consistent identities. Although this capacity was recognized long ago, our mechanistic understanding of the establishment, maintenance, and erasure of cellular identities in plants remains limited. Here, we develop a cell-type–specific reprogramming system that can be probed at the genome-wide scale for alterations in gene expression and histone modifications. We show that relationships among H3K27me3, H3K4me3, and gene expression in single cell types mirror trends from complex tissue, and that H3K27me3 dynamics regulate guard cell identity. Further, upon initiation of reprogramming, guard cells induce H3K27me3-mediated repression of a regulator of wound-induced callus formation, suggesting that cells in intact tissues may have mechanisms to sense and resist inappropriate dedifferentiation. The matched ChIP-sequencing (seq) and RNA-seq datasets created for this analysis also serve as a resource enabling inquiries into the dynamic and global-scale distribution of histone modifications in single cell types in plants.
ROS-based lethality of
Caenorhabditis elegans
mitochondrial electron transport mutants grown on
Escherichia coli
siderophore iron release mutants
Authors: Govindan J. Amaranath , Jayamani Elamparithi , Ruvkun Gary
Published: October 2019

Significance

The animal mitochondrion has a bacterial origin and depends on vitamins and other biochemicals produced by bacteria. In a genetic search for mitochondrial biochemical dependencies when the animal
Caenorhabditis elegans
is feeding on
Escherichia coli
as its sole nutritional source, we identified 45
E. coli
mutations that disrupt mitochondrial function. Four of these
E. coli
mutations that disrupt the transport and removal of iron from an iron retrieval cofactor were lethal in combination with
C. elegans
mitochondrial mutations. Antioxidants strongly suppressed this inviability, suggesting a reactive oxygen toxicity. Iron retrieval cofactors produced by one bacterial species are often hijacked by other bacterial species. The toxicity of this iron retrieval cofactor may be a selected additional function of this biochemical.
The interaction between timing of explicit grammar explanation and individual differences in second language
acquisition
Authors: Kachinske Ilina , DeKeyser Robert
Published: October 2019

Despite numerous positive findings of explicit instruction, this topic continues to engage scholars worldwide. One
issue that may be crucial for the effectiveness of explicit instruction is the interaction between cognitive individual
differences (language aptitude and working memory) and types of instruction. In this experiment, 128 learners of Spanish were
randomly assigned to four experimental treatments and completed comprehension-based practice for interpreting object-verb and
ser/estar sentences in Spanish. Results revealed that the various combinations of rules and practice posed differential task
demands on the learners and consequently drew on language aptitude and working memory to a different extent. We argue that not
only are rules and practice both necessary, but that their suitable integration ameliorates task demands, reducing the burden on
the learner, and accordingly mitigates the role of participants’ individual differences, thus making a substantial difference for
the learning of second language grammar.
Influence of the playing surface on changes of direction and plantar pressures during an agility test in youth futsal players
Authors: Serrano Carlos , Sánchez‐Sánchez Javier , López‐Fernández Jorge , Hernando Enrique , Gallardo Leonor
Published: October 2019

The ability to effect a change of direction (COD) when performing high‐speed actions is essential in team sports like futsal. Nevertheless, the interaction effect of sports surfaces on this ability remains unknown. This research aimed to analyse the plantar pressures and time performance of 15 youth futsal players when performing CODs on two playing surfaces with different mechanical properties. The shock absorption and vertical deformation of one synthetic flooring surface and one wooden flooring surface were assessed. CODs were evaluated using a modified version of the Agility T‐Test, while total time of the test, time of CODs, and plantar pressure in CODs were all recorded. The wooden flooring surface displayed higher values of shock absorption (35.70% ± 2.87%) and vertical deformation (2.77 ± 0.38 mm) compared with the synthetic flooring (p < 0.01). Faster CODs were performed on the wooden flooring than on the synthetic flooring (−0.05 s, 95% confidence interval [CI]: −0.10 to −0.007, effect size [ES]: 0.07, p < 0.05), but no differences in total test time were found (p > 0.05). Finally, no differences in plantar pressures by playing surface were found. In sum, the differences in the mechanical properties of the two futsal surfaces affected the performance of futsal players in the modified agility test. However, these differences were not great enough to generate different plantar pressures on players, probably due to playerś own adaptations.
Mechanosensing during directed cell migration requires dynamic actin polymerization at focal adhesions
Authors: Puleo Julieann I. , Parker Sara S. , Roman Mackenzie R. , Watson Adam W. , Eliato Kiarash Rahmani , Peng Leilei , Saboda Kathylynn , Roe Denise J. , Ros Robert , Gertler Frank B. , Mouneimne Ghassan
Published: October 2019

The mechanical properties of a cell’s microenvironment influence many aspects of cellular behavior, including cell migration. Durotaxis, the migration toward increasing matrix stiffness, has been implicated in processes ranging from development to cancer. During durotaxis, mechanical stimulation by matrix rigidity leads to directed migration. Studies suggest that cells sense mechanical stimuli, or mechanosense, through the acto-myosin cytoskeleton at focal adhesions (FAs); however, FA actin cytoskeletal remodeling and its role in mechanosensing are not fully understood. Here, we show that the Ena/VASP family member, Ena/VASP-like (EVL), polymerizes actin at FAs, which promotes cell-matrix adhesion and mechanosensing. Importantly, we show that EVL regulates mechanically directed motility, and that suppression of EVL expression impedes 3D durotactic invasion. We propose a model in which EVL-mediated actin polymerization at FAs promotes mechanosensing and durotaxis by maturing, and thus reinforcing, FAs. These findings establish dynamic FA actin polymerization as a central aspect of mechanosensing and identify EVL as a crucial regulator of this process.
Social Media as an Emerging Data Resource for Epidemiologic Research: Characteristics of Regular and Nonregular Social Media Users in Nurses’ Health Study II
Authors: Kim Eric S , James Peter , Zevon Emily S , Trudel-Fitzgerald Claudia , Kubzansky Laura D , Grodstein Francine
Published: October 2019

With advances in natural language processing and machine learning, researchers are leveraging social media as a low-cost, low-burden method for measuring various psychosocial factors. However, it is unclear whether information derived from social media is generalizable to broader populations, especially middle-aged and older adults. Using data on women aged 53–70 years from Nurses’ Health Study II (2017–2018; n = 49,045), we assessed differences in sociodemographic characteristics, health conditions, behaviors, and psychosocial factors between regular and nonregular users of Facebook (Facebook, Inc., Menlo Park, California). We evaluated effect sizes with phi (φ) coefficients (categorical data) or Cohen’s d (continuous data) and calculated odds ratios with 95% confidence intervals. While most comparisons between regular and nonregular users achieved statistical significance in this large sample, effect sizes were mostly “very small” (conventionally defined as φ or d <0.01) (e.g., optimism score: meanregular users = 19 vs. meannonregular users = 19 (d = −0.03); physical activity: meanregular users = 24 metabolic equivalent of task (MET)-hours/week vs. meannonregular users = 24 MET-hours/week (d = 0.01)). Some factors had slightly larger differences for regular users versus nonregular users (e.g., depression: 28% vs. 23% (φ = 0.05); odds ratio = 1.27 (95% confidence interval: 1.22, 1.33); obesity: 34% vs. 26% (φ = 0.07); odds ratio = 1.42 (95% confidence interval: 1.36, 1.48)). Results suggest that regular Facebook users were similar to nonregular users across sociodemographic and psychosocial factors, with modestly worse health regarding obesity and depressive symptoms. In future research, investigators should evaluate other demographic groups.
Fluoroquinolone Use and Seasonal Patterns of Ciprofloxacin Resistance in Community-Acquired Urinary Escherichia coli Infection in a Large Urban Center
Authors: Soucy Jean-Paul R , Schmidt Alexandra M , Quach Caroline , Buckeridge David L
Published: October 2019

Urinary tract infections caused by the bacterium Escherichia coli are among the most frequently encountered infections and are a common reason for antimicrobial prescriptions. Resistance to fluoroquinolone antimicrobial agents, particularly ciprofloxacin, has increased in recent decades. It is intuitive that variation in fluoroquinolone resistance is driven by changes in antimicrobial use, but careful study of this association requires the use of time-series methods. Between April 2010 and December 2014, we studied seasonal variation in resistance to ciprofloxacin, trimethoprim-sulfamethoxazole, and ampicillin in community-acquired urinary E. coli isolates in Montreal, Quebec, Canada. Using dynamic linear models, we investigated whether seasonal variation in resistance could be explained by seasonal variation in community antimicrobial use. We found a positive association between total fluoroquinolone use lagged by 1 and 2 months and the proportion of isolates resistant to ciprofloxacin. Our results suggest that resistance to ciprofloxacin is responsive to short-term variation in antimicrobial use. Thus, antimicrobial stewardship campaigns to reduce fluoroquinolone use, particularly in the winter when use is highest, are likely to be a valuable tool in the struggle against antimicrobial resistance.