bluuebunny/crossref_metadata_2025 huggingface dataset:
Precise dynamic initialisation of fixed‐speed wind turbines under active‐stall and active‐pitch controls from their aerodynamic power coefficients using unified Newton–Raphson power‐flow approach
Authors: Aree Pichai
Published: April 2017

Vast majority of already‐installed grid‐connected wind turbines is fixed‐speed wind generators (FSWGs). Their initialisations for power‐system dynamic simulations are mostly performed using conventional power‐flow approach, causing an unavoidable reactive‐power discrepancy between power‐flow result and generator dynamic model. To eliminate this problem, unified Newton–Raphson (NR) power‐flow approach together with wind‐turbine aerodynamic power coefficient is applied for accurate initialisation of the FSWG under passive‐stall regulation. However, FSWG initialisations relating to two other active‐stall and active‐pitch regulations under the same approach have not yet been addressed. Therefore, in this study, the unified power‐flow approach is straightforwardly extended to yield efficient and precise dynamic initialisations of active‐stall‐ and active‐pitch‐regulated FSWGs. In the proposed model, variables of generators and wind turbines are fully solved all together with the power coefficients. The obtained power‐flow result is compared with the published result for model verification. Efficiency of the extended algorithm is demonstrated using IEEE‐300bus and 118bus networks with large groups of wind power plants. The simulation results reveal that the extended algorithm not only gives precise steady‐state initialisation of the FSWGs but also retains NR quadratic convergence characteristics.
Optimal hourly scheduling of distributed generation and capacitors for minimisation of energy loss and reduction in capacitors switching operations
Authors: Ghanegaonkar Sunanda P. , Pande V.N.
Published: April 2017

Now‐a‐days electric power systems all over the world are undergoing a phase of increased size and complexity due to rising load demand expansion. This situation leads to excessive burden on the power distribution systems posing many challenges before the distribution system utilities. Minimisation of real power loss and maintaining voltage profile are the major requirements for a distribution system apart from cost reduction. Capacitors and tap changing transformers are being conventionally used for maintaining voltage profile along a primary distribution network. When a distributed generation (DG) is incorporated in a distribution system, the problem of efficiently controlling a system becomes more complex. In this study, a novel multi‐objective optimisation problem of hourly scheduling of voltage control devices in coordination with a DG is attempted. An efficient particle swarm optimisation technique is used to solve the problem. Another novelty of this work is the use of Newton‐based power flow method for evaluation of function value. The algorithm proposed is validated on IEEE standard 33 bus and 69 bus radial distribution systems. The results are encouraging.
Combined effects for fractional Schrödinger–Kirchhoff systems with critical nonlinearities
Authors: Mingqi Xiang , Rădulescu Vicenţiu D. , Zhang Binlin
Published: April 2017

In this paper, we investigate the existence of solutions for critical Schrödinger–Kirchhoff type systems driven by nonlocal integro–differential operators. As a particular case, we consider the following system:

[see formula in PDF]

where (–Δ)spis the fractionalp–Laplace operator with 0 <s< 1
 1 withα+β=p*s,M: ℝ+0 → ℝ+0is a continuous function,V: ℝN→ ℝ+is a continuous function, λ > 0 is a real parameter. By applying the mountain pass theorem and Ekeland’s variational principle, we obtain the existence and asymptotic behaviour of solutions for the above systems under some suitable assumptions. A distinguished feature of this paper is that the above systems are degenerate, that is, the Kirchhoff function could vanish at zero. To the best of our knowledge, this is the first time to exploit the existence of solutions for fractional Schrödinger–Kirchhoff systems involving critical nonlinearities in ℝN.
The Role of PEG on Pd- and Cu-Catalyzed Cross-Coupling Reactions
Authors: Pires Marina , Purificação Sara , Santos A. , Marques M.
Published: April 2017

Carbon–carbon and carbon–heteroatom coupling reactions are among the most important transformations in organic synthesis as they enable complex structures to be formed from readily available compounds under different routes and conditions. Several metal-catalyzed cross-coupling reactions have been developed creating many efficient methods accessible for the direct formation of new bonds between differently hybridized carbon atoms.

During the last decade, much effort has been devoted towards improvement of the sustainability of these reactions, such as catalyst recovery and atom efficiency. Polyethylene glycol (PEG) can be used as a medium, as solid-liquid phase transfer catalyst, or even as a polymer support. PEG has been investigated in a wide variety of cross-coupling reactions either as an alternative solvent to the common organic solvents or as a support for catalyst, substrate, and ligand. In this review we will summarize the different roles of PEG in palladium- and copper-catalyzed cross-coupling reactions, with the focus on Heck, Suzuki–Miyaura, Sonogashira, Buchwald–Hartwig, Stille, Fukuyama, and homocoupling reactions. We will highlight the role of PEG, the preparation of PEGylated catalysts and substrates, and the importance for the reaction outcome and applicability.

1 Introduction

2 PEG in Heck Reactions

3 PEG in Homocoupling Reactions

4 PEG in Suzuki–Miyaura Reactions

5 PEG in Sonogashira Reactions

6 PEG in Buchwald–Hartwig Reactions

7 PEG in Stille Reactions

8 PEG in Fukuyama Reactions

9 PEG in Miscellaneous Cross-Coupling Routes

10 Conclusions
Effect of Low-Dose Aspirin on the Time of Onset of Preeclampsia and Time of Delivery
Authors: Marrs Caroline , Costantine Maged , Pacheco Luis , Saade George , Chiossi Giuseppe , Dixon C.
Published: April 2017

Objective To determine whether low-dose aspirin (LDA) affects the time of onset of preeclampsia and the time of delivery in high-risk women.

Study Design Secondary analysis of a multicenter randomized controlled trial of LDA (60 mg) in high-risk women. Quantile regression was used to identify the median gestational age at preeclampsia diagnosis and median gestational age at delivery, whereas logistic regression was used to determine the likelihood of preeclampsia-indicated delivery within 7 days.

Results Total of 2,479 women were randomized and 461 developed preeclampsia. The mean gestational age at enrollment was 20 ± 4 weeks. On multivariate analysis, LDA did not affect the time of preeclampsia diagnosis (coefficient −0.4 weeks, 95% CI: −1.1 to 0.2; p = 0.2), time of delivery (coefficient 0 weeks, 95% CI: −0.3 to 0.3; p = 1), or likelihood of preeclampsia-indicated delivery within 7 days (OR = 0.8; 95% CI: 0.5–1.2; p = 0.2). In multifetal gestations, preeclampsia was diagnosed at least 1 week earlier than women with diabetes or previous preeclampsia (p < 0.05), and delivery occurred at least 2 weeks prior (p < 0.001).

Conclusion LDA prophylaxis did not significantly affect time of diagnosis of preeclampsia, time of delivery, or likelihood of preeclampsia-indicated delivery within 7 days. LDA prophylaxis did not significantly affect time of diagnosis of preeclampsia, time of delivery, or likelihood of preeclampsia-indicated delivery within 7 days.
Adrenal Vein Catecholamine Levels and Ratios: Reference Intervals Derived from Patients with Primary Aldosteronism
Authors: Sze Candy , O’Toole Samuel , Tirador Roger , Akker Scott , Matson Matthew , Perry Leslie , Druce Maralyn , Dekkers Tanja , Deinum Jaap , Lenders Jacques , Eisenhofer Graeme , Drake William
Published: April 2017

Phaeochromocytoma localisation is generally reliably achieved with modern imaging techniques, particularly in sporadic cases. On occasion, however, there can be diagnostic doubt due to the presence of bilateral adrenal abnormalities, particularly in patients with mutations in genes predisposing them to the development of multiple phaeochromocytomas. In such cases, surgical intervention is ideally limited to large or functional lesions due to the long-term consequences associated with hypoadrenalism. Adrenal venous sampling (AVS) for catecholamines has been used in this situation to guide surgery, although there are few data available to support diagnostic thresholds. Retrospective analyses of AVS results from 2 centres were carried out. A total of 172 patients (88 men, 84 women) underwent AVS under cosyntropin stimulation for the diagnosis of established primary aldosteronism (PA) with measurement of adrenal and peripheral venous cortisol, aldosterone and catecholamines. Six patients (3 men, 3 women) with phaeochromocytoma underwent AVS for diagnostic purposes with subsequent histological confirmation. Reference intervals for the adrenal venous norepinephrine to epinephrine ratio were created from the PA group. Using the 97.5th centile (1.21 on the left, 1.04 on the right), the false negative rate in the phaeochromocytoma group was 0%. In conclusion, this study describes the largest dataset of adrenal venous catecholamine measurements and provides reference intervals in patients without phaeochromocytoma. This strengthens the certainty with which conclusions related to adrenal venous sampling for catecholamines can be drawn, acknowledging the procedure is not part of the routine diagnostic workup and is an adjunct for use only in difficult clinical cases.
Central and Peripheral Glucagon Reduces Hyperlipidemia in Rats and Hamsters
Authors: Patel Vishal , Joharapurkar Amit , Kshirsagar Samadhan , Patel Hiren , Pandey Dheerendra , Patel Dipam , Shah Kiran , Bahekar Rajesh , Shah Gaurang , Jain Mukul
Published: April 2017

Increased lipid levels in blood contribute to increasing the risk of diabetic complications. Glucagon exerts lipid lowering effects in diabetic state. However, the mechanism behind the lipid reduction by glucagon independent of glucose homeostasis is not well understood. We assessed the actions of glucagon on lipid modulation in blood and markers in liver in hyperlipidemic hamsters and rats.

Male Sprague Dawley rats and Golden Syrian hamsters on a hyperlipidemic diet for 2 weeks were administered a single dose of glucagon by subcutaneous (SC, 150 and 300 µg/kg) or intracerebroventricular (ICV, 15 and 30 µg/animal) route. Effect of acute treatment was observed on tyloxapol-induced hypertriglyceridemia, corn oil-induced post-prandial lipemia, and bile flow. A repeated dose treatment by subcutaneous (300 µg/kg) or intracerebroventricular (30 µg/animal) route was done for 2 weeks, following which circulating and hepatic lipids, hepatic markers of lipid metabolism and bile flow were assessed.

Acute administration of glucagon (SC and ICV) decreased triglyceride absorption, hepatic triglyceride secretion rate and increased excretion of cholesterol in bile fluid in dose related manner. Repeated dose treatment reduced circulating and hepatic lipids and mainly LDL, and enhanced cholesterol excretion in bile. In liver, expression of HMG-CoA reductase was reduced while that of ABCA1 was increased after repeated treatment, whereas pair fed group did not show significant changes when compared to the control group.

These findings demonstrate that central as well as peripheral glucagon effectively reduces hyperlipidemia in rat and hamster model, by modulating hepatic lipid metabolism.
Diagnosis of Pulmonary Artery Embolism: Comparison of Single-Source CT and 3rd Generation Dual-Source CT using a Dual-Energy Protocol Regarding Image Quality and Radiation Dose
Authors: Petritsch Bernhard , Kosmala Aleksander , Gassenmaier Tobias , Weng Andreas , Veldhoen Simon , Kunz Andreas , Bley Thorsten
Published: April 2017

Purpose To compare radiation dose, subjective and objective image quality of 3 rd generation dual-source CT (DSCT) and dual-energy CT (DECT) with conventional 64-slice single-source CT (SSCT) for pulmonary CTA.

Materials and Methods 180 pulmonary CTA studies were performed in three patient cohorts of 60 patients each. Group 1: conventional SSCT 120 kV (ref.); group 2: single-energy DSCT 100 kV (ref.); group 3: DECT 90/Sn150 kV. CTDIvol, DLP, effective radiation dose were reported, and CT attenuation (HU) was measured on three central and peripheral levels. The signal-to-noise-ratio (SNR) and contrast-to-noise-ratio (CNR) were calculated. Two readers assessed subjective image quality according to a five-point scale.

Results Mean CTDIvol and DLP were significantly lower in the dual-energy group compared to the SSCT group (p < 0.001 [CTDIvol]; p < 0.001 [DLP]) and the DSCT group (p = 0.003 [CTDIvol]; p = 0.003 [DLP]), respectively. The effective dose in the DECT group was 2.79 ± 0.95 mSv and significantly smaller than in the SSCT group (4.60 ± 1.68 mSv, p < 0.001) and the DSCT group (4.24 ± 2.69 mSv, p = 0.003). The SNR and CNR were significantly higher in the DSCT group (p < 0.001). Subjective image quality did not differ significantly among the three protocols and was rated good to excellent in 75 % (135/180) of cases with an inter-observer agreement of 80 %.

Conclusion Dual-energy pulmonary CTA protocols of 3 rd generation dual-source scanners allow for significant reduction of radiation dose while providing excellent image quality and potential additional information by means of perfusion maps.

Key Points:

Citation Format
Evidence-Based Guidelines for the Pharmacologic Management of Methamphetamine Dependence, Relapse Prevention, Chronic Methamphetamine-Related, and Comorbid Psychiatric Disorders in Post-Acute Settings
Authors: Härtel-Petri Roland , Krampe-Scheidler Anne , Braunwarth Wolf-Dietrich , Havemann-Reinecke Ursula , Jeschke Peter , Looser Winfried , Mühlig Stephan , Schäfer Ingo , Scherbaum Norbert , Bothe Lydia , Schaefer Corinna , Hamdorf Willem
Published: April 2017

The increasing abuse of the street drug crystal meth (methamphetamine) in many countries worldwide has resulted in a growing demand to treat patients who have acquired a methamphetamine-related disorder. The results of a systematic literature search which led to the consensus-based recommendations by the Working Group of the German Agency for Quality in Medicine (Ärztliches Zentrum für Qualität in der Medizin - ÄZQ) are presented. Pharmacological treatments were reviewed in 58 out of the 103 publications included. They were mainly randomized controlled trials (RCT). Despite increased research activities, none of the medications studied demonstrated a convincing and consistent effect on abstinence rates, despite some having an impact on craving and retention rates or symptom control. In addition, as yet there is no sufficient evidence available for dopamine analogue treatment (“substitution”) after the initial withdrawal-period. Methamphetamine-related, post-acute persistent or comorbid syndromes such as methamphetamine-associated psychosis (MAP), depressive syndromes, anxiety, and sleep disorders are usually treated in a symptom-oriented manner. Risks of interactions with methamphetamine have to be taken in account when prescribing medications with doubtful efficacy. Further research is warranted.
Total Serum Antioxidant Capacity in Healthy Normal Weight and Asymptomatic Overweight Adults
Authors: Petelin Ana , Tedeschi Paola , Maietti Annalisa , Jurdana Mihaela , Brandolini Vincenzo , Pražnikar Zala
Published: April 2017

Obesity and overweight are major contributors to the burden of chronic disease. Both are defined as abnormal or excessive fat accumulation and by increased production of free radicals leading to oxidative stress. The aim of the present study was to evaluate whether overweight and fat accumulation is associated with serum total antioxidant capacity (TAC) in men and women, irrespective of nutritional habits, nutrient intakes, physical activity, smoking, and other confounders, which may be responsible for modifying the association between serum TAC and overweight/obesity measures.

This cross-sectional study was conducted on 60 normal weight and 60 overweight adults aged 25–49. All participants underwent standard anthromorphological measurements of body composition, blood pressure and biochemical measurements, aerobic capabilities assessment and dietary intake evaluation. TAC was measured by using the photochemioluminescence method. All data were analysed with SPSS software.

Men had higher values of TAC than women and concentrations of TAC were significantly higher in overweight subjects compared to normal weight subjects. In the present study TAC tended to be increased by various metabolic risk factors, especially overweight/obesity parameters (body mass index, body fat), inflammation and increased serum levels of Cysteine, irrespective of nutritional habits, nutrient intakes, physical activity and smoking.

Overweight and obesity at an early stage may stimulate TAC. Therefore, the elevation of TAC in overweight adults may be a compensatory response to oxidative stress, generated by reactive oxygen species.
Benchmark coupled-cluster g-tensor calculations with full inclusion of the two-particle spin-orbit contributions
Authors: Perera Ajith , Gauss Jürgen , Verma Prakash , Morales Jorge A.
Published: April 2017

We present a parallel implementation to compute electron spin resonance g-tensors at the coupled-cluster singles and doubles (CCSD) level which employs the ACES III domain-specific software tools for scalable parallel programming, i.e., the super instruction architecture language and processor (SIAL and SIP), respectively. A unique feature of the present implementation is the exact (not approximated) inclusion of the five one- and two-particle contributions to the g-tensor [i.e., the mass correction, one- and two-particle paramagnetic spin-orbit, and one- and two-particle diamagnetic spin-orbit terms]. Like in a previous implementation with effective one-electron operators [J. Gauss et al., J. Phys. Chem. A 113, 11541–11549 (2009)], our implementation utilizes analytic CC second derivatives and, therefore, classifies as a true CC linear-response treatment. Therefore, our implementation can unambiguously appraise the accuracy of less costly effective one-particle schemes and provide a rationale for their widespread use. We have considered a large selection of radicals used previously for benchmarking purposes including those studied in earlier work and conclude that at the CCSD level, the effective one-particle scheme satisfactorily captures the two-particle effects less costly than the rigorous two-particle scheme. With respect to the performance of density functional theory (DFT), we note that results obtained with the B3LYP functional exhibit the best agreement with our CCSD results. However, in general, the CCSD results agree better with the experimental data than the best DFT/B3LYP results, although in most cases within the rather large experimental error bars.
Algorithmic characterization results for the Kerr-NUT-(A)dS space-time. II. KIDs for the Kerr-(A)(de Sitter) family
Authors: Paetz Tim-Torben
Published: April 2017

We characterize Cauchy data sets leading to vacuum space-times with vanishing Mars-Simon tensor. This approach provides an algorithmic procedure to check whether a given initial data set (Σ,hij,Kij) evolves into a space-time which is locally isometric to a member of the Kerr-(A)(dS) family.
Effect of buried extended defects on the radiation tolerance of ZnO
Authors: Azarov Alexander , Wendler Elke , Lorenz Katharina , Monakhov Edouard , Svensson Bengt G.
Published: April 2017

Interaction between defects of different types often determines their evolution in semiconductors under ion irradiation. Here, we investigate the role of buried pre-existing extended defects in the damage accumulation in ZnO single crystals implanted at room temperature and at 15 K with 80 keV N ions. For the room temperature implants but not for the 15 K ones, the defect accumulation around the projected range is strongly suppressed while a pronounced build-up occurs in the region of the pre-existing defects. This is attributed to thermally activated migration of point defects from the implanted volume and subsequent trapping/annihilation by the pre-existing defects. The obtained results imply that a defect engineering scheme involving formation of a high density of extended defects outside the active volume of a ZnO-based device could be beneficial to enhance the radiation tolerance.
Self-similarity and quasi-idempotence in neural networks and related dynamical systems
Authors: Minati Ludovico , Winkel Julia , Bifone Angelo , Oświęcimka Paweł , Jovicich Jorge
Published: April 2017

Self-similarity across length scales is pervasively observed in natural systems. Here, we investigate topological self-similarity in complex networks representing diverse forms of connectivity in the brain and some related dynamical systems, by considering the correlation between edges directly connecting any two nodes in a network and indirect connection between the same via all triangles spanning the rest of the network. We note that this aspect of self-similarity, which is distinct from hierarchically nested connectivity (coarse-grain similarity), is closely related to idempotence of the matrix representing the graph. We introduce two measures, ι(1) and ι(∞), which represent the element-wise correlation coefficients between the initial matrix and the ones obtained after squaring it once or infinitely many times, and term the matrices which yield large values of these parameters “quasi-idempotent”. These measures delineate qualitatively different forms of “shallow” and “deep” quasi-idempotence, which are influenced by nodal strength heterogeneity. A high degree of quasi-idempotence was observed for partially synchronized mean-field Kuramoto oscillators with noise, electronic chaotic oscillators, and cultures of dissociated neurons, wherein the expression of quasi-idempotence correlated strongly with network maturity. Quasi-idempotence was also detected for macro-scale brain networks representing axonal connectivity, synchronization of slow activity fluctuations during idleness, and co-activation across experimental tasks, and preliminary data indicated that quasi-idempotence of structural connectivity may decrease with ageing. This initial study highlights that the form of network self-similarity indexed by quasi-idempotence is detectable in diverse dynamical systems, and draws attention to it as a possible basis for measures representing network “collectivity” and pattern formation.
Field-theoretic simulations of block copolymer nanocomposites in a constant interfacial tension ensemble
Authors: Koski Jason P. , Riggleman Robert A.
Published: April 2017

Block copolymers, due to their ability to self-assemble into periodic structures with long range order, are appealing candidates to control the ordering of functionalized nanoparticles where it is well-accepted that the spatial distribution of nanoparticles in a polymer matrix dictates the resulting material properties. The large parameter space associated with block copolymer nanocomposites makes theory and simulation tools appealing to guide experiments and effectively isolate parameters of interest. We demonstrate a method for performing field-theoretic simulations in a constant volume-constant interfacial tension ensemble (nVγT) that enables the determination of the equilibrium properties of block copolymer nanocomposites, including when the composites are placed under tensile or compressive loads. Our approach is compatible with the complex Langevin simulation framework, which allows us to go beyond the mean-field approximation. We validate our approach by comparing our nVγT approach with free energy calculations to determine the ideal domain spacing and modulus of a symmetric block copolymer melt. We analyze the effect of numerical and thermodynamic parameters on the efficiency of the nVγT ensemble and subsequently use our method to investigate the ideal domain spacing, modulus, and nanoparticle distribution of a lamellar forming block copolymer nanocomposite. We find that the nanoparticle distribution is directly linked to the resultant domain spacing and is dependent on polymer chain density, nanoparticle size, and nanoparticle chemistry. Furthermore, placing the system under tension or compression can qualitatively alter the nanoparticle distribution within the block copolymer.
Magnetic field production via the Weibel instability in interpenetrating plasma flows
Authors: Huntington C. M. , Manuel M. J.-E. , Ross J. S. , Wilks S. C. , Fiuza F. , Rinderknecht H. G. , Park H.-S. , Gregori G. , Higginson D. P. , Park J. , Pollock B. B. , Remington B. A. , Ryutov D. D. , Ruyer C. , Sakawa Y. , Sio H. , Spitkovsky A. , Swadling G. F. , Takabe H. , Zylstra A. B.
Published: April 2017

Many astrophysical systems are effectively “collisionless,” that is, the mean free path for collisions between particles is much longer than the size of the system. The absence of particle collisions does not preclude shock formation, however, as shocks can be the result of plasma instabilities that generate and amplify electromagnetic fields. The magnetic fields required for shock formation may either be initially present, for example, in supernova remnants or young galaxies, or they may be self-generated in systems such as gamma-ray bursts (GRBs). In the case of GRB outflows, the Weibel instability is a candidate mechanism for the generation of sufficiently strong magnetic fields to produce shocks. In experiments on the OMEGA Laser, we have demonstrated a quasi-collisionless system that is optimized for the study of the non-linear phase of Weibel instability growth. Using a proton probe to directly image electromagnetic fields, we measure Weibel-generated magnetic fields that grow in opposing, initially unmagnetized plasma flows. The collisionality of the system is determined from coherent Thomson scattering measurements, and the data are compared to similar measurements of a fully collisionless system. The strong, persistent Weibel growth observed here serves as a diagnostic for exploring large-scale magnetic field amplification and the microphysics present in the collisional–collisionless transition.
HCl dissociating on a rigid Au(111) surface: A six-dimensional quantum mechanical study on a new potential energy surface based on the RPBE functional
Authors: Liu Tianhui , Fu Bina , Zhang Dong H.
Published: April 2017

The dissociative chemisorption of HCl on the Au(111) surface has recently been an interesting and important subject, regarding the discrepancy between the theoretical dissociation probabilities and the experimental sticking probabilities. We here constructed an accurate full-dimensional (six-dimensional (6D)) potential energy surface (PES) based on the density functional theory (DFT) with the revised Perdew-Burke-Ernzerhof (RPBE) functional, and performed 6D quantum mechanical (QM) calculations for HCl dissociating on a rigid Au(111) surface. The effects of vibrational excitations, rotational orientations, and site-averaging approximation on the present RPBE PES are investigated. Due to the much higher barrier height obtained on the RPBE PES than on the PW91 PES, the agreement between the present theoretical and experimental results is greatly improved. In particular, at the very low kinetic energy, the QM-RPBE dissociation probability agrees well with the experimental data. However, the computed QM-RPBE reaction probabilities are still markedly different from the experimental values at most of the energy regions. In addition, the QM-RPBE results achieve good agreement with the recent ab initio molecular dynamics calculations based on the RPBE functional at high kinetic energies.
Structure and structure-preserving algorithms for plasma physics
Authors: Morrison P. J.
Published: April 2017

Hamiltonian and action principle (HAP) formulations of plasma physics are reviewed for the purpose of explaining structure preserving numerical algorithms. Geometric structures associated with and emergent from HAP formulations are discussed. These include conservative integration, which exactly conserves invariants, symplectic integration, which exactly preserves the Hamiltonian geometric structure, and other Hamiltonian integration techniques. Basic ideas of variational integration and Poisson integration, which can preserve the noncanonical Hamiltonian structure, are discussed. Metriplectic integration, which preserves the structure of conservative systems with both Hamiltonian and dissipative parts, is proposed. Two kinds of simulated annealing, a relaxation technique for obtaining equilibrium states, are reviewed: one that uses metriplectic dynamics, which maximizes an entropy at fixed energy, and the other that uses double bracket dynamics, which preserves Casimir invariants. Throughout, applications to plasma systems are emphasized. The paper culminates with a discussion of geometric electromagnetic particle-in-cell [Kraus et al., J. Plasma Phys. (to be published); e-print arXiv:1609.03053v1 [math.NA]], a particle in cell code that incorporates Hamiltonian and geometrical structure preserving properties.
Discrete rational and breather solution in the spatial discrete complex modified Korteweg-de Vries equation and continuous counterparts
Authors: Zhao Hai-qiong , Yu Guo-fu
Published: April 2017

In this paper, a spatial discrete complex modified Korteweg-de Vries equation is investigated. The Lax pair, conservation laws, Darboux transformations, and breather and rational wave solutions to the semi-discrete system are presented. The distinguished feature of the model is that the discrete rational solution can possess new W-shape rational periodic-solitary waves that were not reported before. In addition, the first-order rogue waves reach peak amplitudes which are at least three times of the background amplitude, whereas their continuous counterparts are exactly three times the constant background. Finally, the integrability of the discrete system, including Lax pair, conservation laws, Darboux transformations, and explicit solutions, yields the counterparts of the continuous system in the continuum limit.
Oxygen partial pressure dependence of thermoelectric power factor in polycrystalline n-type SrTiO3: Consequences for long term stability in thermoelectric oxides
Authors: Sharma Peter A. , Brown-Shaklee Harlan J. , Ihlefeld Jon F.
Published: April 2017

The Seebeck coefficient and electrical conductivity have been measured as functions of oxygen partial pressure over the range of 10−22 to 10−1 atm at 1173 K for a 10% niobium-doped SrTiO3 ceramic with a grain size comparable to the oxygen diffusion length. Temperature-dependent measurements performed from 320 to 1275 K for as-prepared samples reveal metallic-like conduction and good thermoelectric properties. However, upon exposure to progressively increasing oxygen partial pressure, the thermoelectric power factor decreased over time scales of 24 h, culminating in a three order of magnitude reduction over the entire operating range. Identical measurements on single crystal samples show negligible changes in the power factor so that the instability of ceramic samples is primarily tied to the kinetics of grain boundary diffusion. This work provides a framework for understanding the stability of thermoelectric properties in oxides under different atmospheric conditions. The control of the oxygen atmosphere remains a significant challenge in oxide thermoelectrics.
Low-loss and broadband anomalous Floquet topological insulator for airborne sound
Authors: Peng Yu-Gui , Shen Ya-Xi , Zhao De-Gang , Zhu Xue-Feng
Published: April 2017

Anomalous Floquet topological insulators (AFIs) for airborne sound have recently been realized in experiments. However, the implemented version suffers from significant loss and narrowband due to thermal viscosity and dispersive coupling strength between unit-cells. Here, we propose a solution for realizing low-loss and broadband acoustic AFI. We show that the loss after passing through one unit-cell can be less than 2% for the topological edge states. It is also theoretically unveiled that in the frequency range of nearly unitary coupling (∼0.97 from 4.8 kHz to 7.0 kHz in our case), around 84% corresponds to topological bands. Our proposal may promote the application of large-dimension acoustic topological devices.
Ultra-large elongation and dislocation behavior of nano-sized tantalum single crystals
Authors: Ma Ying , Lu Yan , Kong Deli , Shu Xinyu , Deng Qingsong , Zhou Hao , Chen Yanhui , Zou Jin , Wang Lihua
Published: April 2017

Although extensive simulations and experimental investigations have been carried out, the plastic deformation mechanism of body-centered-cubic (BCC) metals is still unclear. With our home-made device, the in situ tensile tests of single crystal tantalum (Ta) nanoplates with a lateral dimension of ∼200 nm in width and ∼100 nm in thickness were conducted inside a transmission electron microscope. We discovered an unusual ambient temperature (below ∼60°C) ultra-large elongation which could be as large as 63% on Ta nanoplates. The in situ observations revealed that the continuous and homogeneous dislocation nucleation and fast dislocation escape lead to the ultra-large elongation in BCC Ta nanoplates. Besides commonly believed screw dislocations, a large amount of mixed dislocation with b=12<111> were also found during the tensile loading, indicating the dislocation process can be significantly influenced by the small sizes of BCC metals. These results provide basic understanding of plastic deformation in BCC metallic nanomaterials.
Dynamics of soil organic matter in a cultivated chronosequence in the Cerrado (Minas Gerais, Brazil)
Authors: Resende Thalita M. , Rosolen Vania , Bernoux Martial , Moreira Marcelo Z. , Conceição Fabiano T. d. , Govone José S.
Published: April 2017

The vegetation of the Cerrado has been replaced by pastures and agriculture, affecting the stock and dynamic of soil organic matter (SOM). The present study was conducted in a cultivated chronosequence with a mixed system (agriculture+pasture for 15 years; Agric+P15) and cultivated pasture (30 years; P30), taking the native Cerrado as a reference to assess changes in the stock of SOM, the dynamics (δ13C) and the carbon replacement derived from the C3 in native vegetation to C4 in cultivated vegetation. Compared to Cerrado, there was a reduction in C stock in cultivated soils at 0–15-cm depth (reduction of 26.5% in Agri+P15 and 6% in P30). The close similarity between Cerrado and P30 indicates that the pasture management enhanced the stock relative to Agri+P15, but was not effective in sequestering C. Only in the 0–15cm depth was there a marked replacement of C derived from the C3 of Cerrado plants associated with cultivation time. In the chronosequence, the isotopic signature of C4 plants dominated in the soil below 30cm depth, suggesting a paleoclimatic effect on SOM.
The influence of incident management teams on the deployment of wildfire suppression resources
Authors: Hand Michael , Katuwal Hari , Calkin David E. , Thompson Matthew P.
Published: April 2017

Despite large commitments of personnel and equipment to wildfire suppression, relatively little is known about the factors that affect how many resources are ordered and assigned to wildfire incidents and the variation in resources across incident management teams (IMTs). Using detailed data on suppression resource assignments for IMTs managing the highest complexity wildfire incidents (Type 1 and Type 2), this paper examines daily suppression resource use and estimates the variation in resource use between IMTs. Results suggest that after controlling for fire and landscape characteristics, and for higher average resource use on fires in California, differences between IMTs account for ~14% of variation in resource use. Of the 89 IMTs that managed fires from 2007 to 2011, 17 teams exhibited daily resource capacity that was significantly higher than resource use for the median team.
Density dependence in demography and dispersal generates fluctuating invasion speeds
Authors: Sullivan Lauren L. , Li Bingtuan , Miller Tom E. X. , Neubert Michael G. , Shaw Allison K.
Published: April 2017

Significance

Mitigating the spread of invasive species remains difficult—substantial variability in invasion speed is increasingly well-documented, but the sources of this variability are poorly understood. We report a mechanism for invasion speed variability. The combined action of density dependence in demography and dispersal can cause invasions to fluctuate, even in constant environments. Speed fluctuations occur through creation of a pushed invasion wave that moves forward not from small populations at the leading edge but instead, from larger, more established populations that “jump” forward past the previous invasion front. Variability in strength of the push generates fluctuating invasion speeds. Conditions giving rise to fluctuations are widely documented in nature, suggesting that an important source of invasion variability may be overlooked.
On the permeation of large organic cations through the pore of ATP-gated P2X receptors
Authors: Harkat Mahboubi , Peverini Laurie , Cerdan Adrien H. , Dunning Kate , Beudez Juline , Martz Adeline , Calimet Nicolas , Specht Alexandre , Cecchini Marco , Chataigneau Thierry , Grutter Thomas
Published: April 2017

Significance

Unlike many ion channels whose pore conductances remain relatively stable over time, it is thought that prolonged ATP applications to P2X receptors cause a striking increase over time in the permeability of large molecules, a process dubbed pore dilation. However, this mechanism remains poorly understood and highly controversial. Here, we use different methods spanning single-channel recordings, photochemistry, molecular biology, and computations to show that contrary to longstanding view, rapid activation by ATP allows the stable passage of large cations through the P2X pore. We further discover that spermidine, a large natural cation known to modulate other ion channels, is able to transit through many P2X receptors, including those thought to be nondilating. Our data thus reveal an unacknowledged P2X-mediated signaling.
Climate Change Communication in Peru
Authors: Takahashi Bruno , Martinez Alejandra
Published: April 2017

Peru is one of the most biodiverse countries on the planet. More than 65% of the country is covered by the Amazon rainforest, and the Andes region is home to more than 70% of the world’s tropical glaciers. This abundance of natural resources also makes the country highly vulnerable to the effects of climate change.

The Peruvian government therefore requires the development and implementation of action plans to adapt to the present and future impacts of climate change. At the same time, it requires the development of sound communication strategies that include collaboration with stakeholders such as the media and nongovernmental organizations. Media coverage of climate change can have important implications for policy decision making. This is especially salient in a context of low information availability where media reports play an important role in filling knowledge gaps that in turn can affect the way policies are developed.

Climate change, as an environmental and social issue in Peru, is not highly politicized, as it is in countries such as the United States and Australia. There is no major debate about the reality of climate change, the scientific evidence, or the need for political action and technological and policy innovations. This approach is also reflected in the media’s coverage of the issue. Peru’s media tend to focus on climate change mostly during key policy events. Among these major events was the capital city of Lima’s hosting in 2010 of the V meeting of Latin American, Caribbean, and European Union countries, where the main topics of discussion were climate change and poverty. In addition, Lima hosted the COP20, which preceded the Paris meeting in 2015 that led to a major global agreement. The media’s coverage of these events was intense. These were the exceptions: A good proportion of Peru’s newspaper coverage comes from international news wire agencies. Coverage from those sources focuses mostly on mitigation actions, instead of adaptation, which is more relevant to vulnerable countries such as Peru. This coverage is in line with the government’s view of mitigation as a business opportunity. There is, however, a lack of studies that explore, first, the factors that affect this coverage, and, second, the way other mediums such as television or radio cover the issue.

Strategic communication by governmental organizations, as well as accurate and fact-based media reporting about climate change, is necessary to better communicate the urgency and magnitude of the problem to the general public, grassroots organizations, industry, and international agencies, among others.
News Media and African Genocide
Authors: Savelsberg Joachim J. , Wahutu j. Siguru
Published: April 2017

Today, genocides and other episodes of mass violence are, under specific circumstances, subject to extensive media reporting. A case in point is the mass violence in Darfur, unfolding during the first decades of the 21st century and categorized as genocide by many, including the International Criminal Court. Media reporting about Darfur shows noteworthy patterns. They are revealed by a study supported by the National Science Foundation, involving content analysis of 3,387 reports and opinion pieces published in prominent newspapers of eight countries in the Global North, accompanied by expert interviews, and a doctoral dissertation on the journalistic field in Africa and its reporting on Darfur. First, today’s media reporting replaces denial with acknowledgment. Second, it frames the violence most often as criminal, and frequently as genocidal, even though humanitarian emergency and armed conflict frames also fare prominently. Third, throughout the history of reporting, Africa correspondents, central actors in the journalistic field, adapt to opportunities and external pressures from surrounding social fields. Economic forces (media markets) and politics affect the frequency of reporting. The criminal justice-oriented human rights field, the humanitarian field, and the diplomatic field influence the frames through which the violence is interpreted. Fourth, the criminal justice-oriented human rights field is especially effective in coloring reports, despite substantial barriers between criminal courts and the journalistic field. Fifth, reporting in all countries is affected by interventions by international institutions, including the UN Security Council, the International Commission of Inquiry on Darfur, and the International Criminal Court (ICC). The ICC’s decision to charge Sudan’s President Omar al-Bashir with war crimes, crimes against humanity, and genocide, for example, intensified reporting in all countries. Sixth, the receptivity to the criminal justice frame varies by country. Seventh, in addition to cross-country similarities and differences within the Global North, a comparison of journalistic fields in the Global North with those in Africa shows distinct patterns, but also astonishing similarities between Global North and African reporting on Darfur.
Diversification of IgG effector functions
Authors: Bournazos Stylianos , Ravetch Jeffrey V
Published: April 2017

IgG is the major immunoglobulin class produced during an immune response against foreign antigens and efficiently provides protection through its bifunctional nature. While the Fab domains confer highly specific recognition of the antigen, the Fc domain mediates a wide range of effector functions that modulate several aspects of innate and adaptive immunity. Engagement of the various types of Fcγ receptors (FcγRs) by an IgG Fc domain can activate distinct immunomodulatory pathways with pleiotropic functional consequences for several leukocyte types. Fc effector functions are not limited to phagocytosis and cytotoxicity of IgG-opsonized targets but exhibit remarkable diversity and include modulation of leukocyte activity and survival, cytokine and chemokine expression, maturation of antigen-presenting cells, antigen processing and presentation, B-cell selection and IgG affinity maturation, as well as regulation of IgG production. These functions are initiated upon specific interactions of the Fc domain with the various types of FcγRs—a process that is largely determined by the structural heterogeneity of the IgG Fc domain. Modulation of the Fc-associated glycan structure and composition along with differences in the primary amino acid sequence among the IgG subclasses represent the two main diversification mechanisms of the Fc domain that generate a spectrum of Fc domain phenotypes with distinct affinity for the various FcγR types and differential capacity to activate immunomodulatory pathways.
Association of Early Outpatient Rehabilitation With Health Service Utilization in Managing Medicare Beneficiaries With Nontraumatic Knee Pain: Retrospective Cohort Study
Authors: Stevans Joel M. , Fitzgerald G. Kelley , Piva Sara R. , Schneider Michael
Published: April 2017

Background. Nontraumatic knee pain (NTKP) is highly prevalent in adults 65 years of age and older. Evidence-based guidelines recommend early use of rehabilitation; however, there is limited information comparing differences in health care utilization when rehabilitation is included in the management of NTKP.

Objectives. To describe the overall health care utilization associated with the management of NTKP; estimate the proportion of people who receive outpatient rehabilitation services; and evaluate the timing of outpatient rehabilitation and its association with other health care utilization.

Design. Rretrospective cohort study was conducted using a random 10% sample of 2009–2010 Medicare claims. The sample included 52,504 beneficiaries presenting within the ambulatory setting for management of NTKP.

Methods. Exposure to outpatient rehabilitative services following the NTKP index ambulatory visit was defined as 1) no rehabilitation; 2) early rehabilitation (1-15 days); 3) intermediate rehabilitation (16-120 days); and 4) late rehabilitation (>120 days). Logistic regression models were fit to analyze the association of rehabilitation timing with narcotic analgesic use, utilization of nonsurgical invasive procedure, and knee surgery during a 12-month follow-up period.

Results. Only 11.1% of beneficiaries were exposed to outpatient rehabilitation services. The likelihood of using narcotics, nonsurgical invasive procedures, or surgery was significantly less (adjusted odds ratios; 0.67, 0.50, 0.58, respectively) for those who received early rehabilitation when compared to no rehabilitation. The exposure-outcome relationships were reversed in the intermediate and late rehabilitation cohorts.

Limitations. This was an observational study, and residual confounding could affect the observed relationships. Therefore, definitive conclusions regarding the causal effect of rehabilitation exposure and reduced utilization of more aggressive interventions cannot be determined at this time.

Conclusions. Early referral for outpatient rehabilitation may reduce the utilization of health services that carry greater risks or costs in those with NTKP.
Patient satisfaction with PAs in the Netherlands
Authors: Meijer Koos , Kuilman Luppo
Published: April 2017

Physician assistants (PAs) were introduced in the Netherlands in 2002 and are now widely deployed. However, little is known about patient satisfaction with Dutch PAs. A comparative study of patient satisfaction was undertaken in the primary care setting. Patients seen by general practitioners (GPs) and PAs were surveyed using the Consumer Quality Index, a European quality survey instrument. Quality of performance indicators included patient satisfaction, effectiveness of treatment, and safety of treatment. The results found that few differences emerged, and Dutch patients appear to be as satisfied with the care received by PAs as with GPs.