bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal power allocation for bi‐directional full duplex underlay cognitive radio networks
Authors: Lan Peng , Zhai Chao , Chen Lizhen , Gao Bin , Sun Fenggang
Published: November 2017

Cognitive radio and full duplex transmissions are regarded as two effective techniques to improve the spectral efficiency. By combining the two promising techniques, the problem of power allocation for bi‐directional full duplex underlay cognitive spectrum sharing is studied. To protect the primary transmission, consider both the instantaneous and statistical channel state information to adjust the transmit powers of secondary users to avoid causing intolerable interference to the primary users. The corresponding quality‐of‐service (QoS) constraints are determined for the primary system. On this basis, propose optimal power allocation schemes to facilitate the secondary transmission while guaranteeing the primary QoS constraint. Simulation results are provided to verify the efficiency of proposed schemes in improving the system capacity.
Pilot hopping algorithm for massive multiple‐input multiple‐output
Authors: Mehana Ahmed Hesham , Alwakeel Ahmed S.
Published: November 2017

In this study, the authors develop a pilot assignment algorithm to alleviate the effect of pilot contamination over time‐varying channels. They study the effect of correlated channel states over consecutive blocks under different Doppler frequencies using a moving‐average channel estimation process. They show that it is possible to mitigate the pilot contamination problem by assigning pilot hopping sequences such that each user experiences different contaminating users across time. The proposed algorithm has the advantage that it does not require the cooperation between the base stations, is robust to the channel time‐variations and can significantly increase the spectral efficiency compared to existing algorithms as shown in the simulation results.
Moringa oleifera: a promising agricultural crop and of social inclusion for Brazil and semi-arid regions for the production of energetic biomass (biodiesel and briquettes)
Authors: Pereira Francisco Sávio Gomes , de Sobral Antonio Demóstenes , da Silva Ana Maria Ribeiro Bastos , da Rocha Maria Aparecida Guilherme
Published: November 2017

This study describes properties of biomasses of Moringa oleifera Lamarck for energetic applications of production of biodiesel and briquettes. The seeds collected of the mature pods were the initial biomasses used of this plant. The seeds were separated into husks and oilseed grains, from which the oils were extracted by mechanical pressing and by solvent extraction. The crude oil mixed (of pressing and by solvent) was degummed, neutralized, washed, dried and characterized. The purified oil was converted into methyl biodiesel in homogeneous alkaline transesterification, which was purified and characterized. The residual peels and pies had their calorific powers measured and compared with classic agricultural residues: firewood, sugarcane bagasse and coconut husks. Moringa culture was compared to soybeans in agricultural and biodiesel production perspectives. The analytical results show that the biomasses of the moringa are favorable as renewable biofuels like biodiesel or briquettes due to the good calorific power and simple and accessible productive technology. The production of briquettes starting from the biomasses of the moringa would be recommended with the uses of the pod husks, seed peels and pies (cakes) of extraction of the oil. The agricultural management and the simple productive technologies applied to the moringa are favorable for social inclusion by enabling family agriculture.
Extended Pigmented Villonodular Synovitis of the Hand
Authors: Irisarri Carlos , Yañez Calvo Javier
Published: November 2017

We present the case of a 36-year-old woman with pigmented villonodular synovitis (PVNS) of the right hand. The magnetic resonance imaging (MRI) showed that the lesion had spread over an unusually wide area. Despite this, after one single operation, there has been no relapse after 5 years, with both the functional and cosmetic results remaining satisfactory.
Komplikationsmanagement der Pankreasanastomose
Authors: Weber Georg , Schmid Axel , Uder Michael , Grützmann Robert
Published: November 2017

Hintergrund Die Pankreasanastomose gilt als die Achillesferse der Pankreaschirurgie. Durch die Ausbildung einer postoperativen Pankreasfistel (POPF) kommt es häufig zu mittel- bis schwergradigen, teilweise lebensbedrohlichen Folgekomplikationen.

Fragestellung Möglichkeiten der Prophylaxe, Diagnostik und Therapie der POPF und der POPF-assoziierten Komplikationen im interdisziplinären Management.

Ergebnisse Aktuelle Studienergebnisse zeigen, dass je nach Einteilung der POPF in Grad A – C unterschiedliche diagnostische und therapeutische Maßnahmen die Morbidität und Mortalität senken. Je nach Zeitpunkt und Schweregrad der POPF sowie der POPF-assoziierten Komplikationen ist ein konservatives/interventionelles Management oder chirurgisches Vorgehen indiziert.

Schlussfolgerung Durch die präzise Einteilung der POPF und der POPF-assoziierten Folgekomplikationen kann durch ein gezieltes interdisziplinäres diagnostisches und therapeutisches Vorgehen die Morbidität und Mortalität nach Pankreasoperationen gesenkt werden.
Effect of Neuromuscular Electrical Stimulation on Brain-derived Neurotrophic Factor
Authors: Miyamoto Toshiaki , Kou Keihou , Yanamoto Hideya , Hashimoto Saya , Ikawa Mai , Sekiyama Takashi , Nakano Yoshiki , Kashiwamura Shin-ichiro , Takeda Chisako , Fujioka Hiroyuki
Published: November 2017

Brain-derived neurotrophic factor (BDNF) has been considered an essential mediator responsible for the beneficial effects of physical activity in preventing cognitive impairment. This study aimed at examining the effects of a single bout of neuromuscular electrical stimulation (NMES) on levels of BDNF in the plasma and on cognitive performance in healthy adult men. Thirteen healthy adult men participated in three experimental sessions. The first session was 30 min of NMES to both legs, the second was 30 min of cycling exercise at the intensity of 60% peak oxygen uptake, and the third was 30 min of complete rest. Blood was examined for plasma BDNF levels and glucose concentrations, and cognitive performance tests were performed before and after each session. A single bout of NMES significantly increased plasma BDNF levels (p<0.05), which were equivalent to the amount of plasma BDNF released during the exercise session (p>0.05). However, there were no significant changes in cognitive performance between the sessions (p>0.05). The present study found that a single bout of NMES significantly increased plasma BDNF to levels normally present during moderate voluntary exercise. Therefore, NMES could serve as an alternative method of exercise, and might shed light on individuals for whom voluntary physical exercise is contraindicated.
Sprint Interval Training Decreases Circulating MicroRNAs Important for Muscle Development
Authors: Denham Joshua , Gray Adrian , Scott-Hamilton John , Hagstrom Amanda
Published: November 2017

Small non-coding RNAs, such as microRNAs (miRNAs), have emerged as powerful post-transcriptional regulators of gene expression that play important roles in many developmental and biological processes. In this study, we assessed the abundance of circulating microRNAs important for skeletal muscle and heart adaptations to exercise (miR-1, miR-133a, miR-133b and miR-486), following acute exercise and short-term sprint interval training (SIT). Twenty-eight individuals completed four all-out efforts on a cycle ergometer, and donated blood before and 30 min after the cessation of exercise. A subset of 10 untrained men completed 4-6 efforts of SIT, three times a week for 6 weeks, and donated resting blood samples before and after the intervention. MiRNA TaqMan qPCR was performed and whilst no changes were observed after a single session of SIT (all p>0.05), the 6-wk SIT intervention significantly reduced the whole blood content of all four miRNAs (mean fold-changes: 0.37–0.48, all p<0.01). Our data suggests that circulating miRNAs are responsive to short-term SIT and could have roles in SIT-induced health and performance adaptations. Further work is required to establish whether circulating miRNAs could serve as biomarkers for predicting exercise training responses and monitoring exercise interventions.
Structural, optical, and electrical characteristics of graphene nanosheets synthesized from microwave-assisted exfoliated graphite
Authors: Chamoli Pankaj , Das Malay K. , Kar Kamal K.
Published: November 2017

In the present study, low defect density graphene nanosheets (GNs) have been synthesized via chemical reduction of exfoliated graphite (EG) in the presence of a green reducing agent, oxalic acid. EG has been synthesized via chemical intercalation of natural flake graphite followed by exfoliation through microwave irradiation at 800 W for 50 s. 50 mg/mL concentration of oxalic acid helps to extract low defect density GNs from EG. As-synthesized GNs have been characterized by X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, UV-Visible spectroscopy, field emission scanning electron microscopy, and X-ray photon spectroscopy. Raman analysis confirms the removal of oxygen functional groups from EG and achieved an ID/IG ratio of ∼0.10 with low defect density (∼1.12 × 1010 cm−2). Elemental analysis supports the Raman signature of the removal of oxygen functionalities from EG, and a high C/O ratio of ∼15.97 is obtained. Further, transparent conducting films (TCFs) have been fabricated by spray coating. The optical and electrical properties of fabricated TCFs have been measured after thermal graphitization. Thermal graphitization helps to improve the optical and electrical properties of TCFs by tuning the optical bandgap in a controlled way. TCF shows best performance when the film is annealed at 900 °C for 1 h in vacuum. It shows a sheet resistance of ∼1.10 kΩ/◻ and a transmittance of ∼71.56% at 550 nm.
Interrelated chemical-microstructural-nanomechanical variations in the structural units of the cuttlebone of Sepia officinalis
Authors: North L. , Labonte D. , Oyen M. L. , Coleman M. P. , Caliskan H. B. , Johnston R. E.
Published: November 2017

“Cuttlebone,” the internalized shell found in all members of the cephalopod family Sepiidae, is a sophisticated buoyancy device combining high porosity with considerable strength. Using a complementary suite of characterization tools, we identified significant structural, chemical, and mechanical variations across the different structural units of the cuttlebone: the dorsal shield consists of two stiff and hard layers with prismatic mineral organization which encapsulate a more ductile and compliant layer with a lamellar structure, enriched with organic matter. A similar organization is found in the chambers, which are separated by septa, and supported by meandering plates (“pillars”). Like the dorsal shield, septa contain two layers with lamellar and prismatic organization, respectively, which differ significantly in their mechanical properties: layers with prismatic organization are a factor of three stiffer and up to a factor of ten harder than those with lamellar organization. The combination of stiff and hard, and compliant and ductile components may serve to reduce the risk of catastrophic failure, and reflect the role of organic matter for the growth process of the cuttlebone. Mechanically “weaker” units may function as sacrificial structures, ensuring a stepwise failure of the individual chambers in cases of overloading, allowing the animals to retain near-neutral buoyancy even with partially damaged cuttlebones. Our findings have implications for our understanding of the structure-property-function relationship of cuttlebone, and may help to identify novel bioinspired design strategies for light-weight yet high-strength foams.
Impact of conductivity on Lorentzian and Fano resonant high-Q THz metamaterials: Superconductor, metal and perfect electric conductor
Authors: Srivastava Yogesh Kumar , Singh Ranjan
Published: November 2017

High temperature superconductors have created exciting opportunities for switchable metamaterial and plasmonic devices operating at terahertz frequencies. In recent times, there have been several demonstrations using superconducting metamaterials, such as thermal, electrical, magnetic, and optical switching. Here, we explore the impact of conductivity on terahertz metamaterial resonators with different resonance line shapes. Lorentzian and Fano line shaped resonators show different levels of enhancement in the quality factor and resonance intensity for metallic, superconductor, and perfect electric conductors, due to the interplay between the radiative and the non-radiative loss mechanisms in a metamaterial array.
Self-organized lattice-matched epitaxy of Si1−xSnx alloys on (001)-oriented Si, Ge, and InP substrates
Authors: Kurosawa Masashi , Kato Motohiro , Takahashi Kouta , Nakatsuka Osamu , Zaima Shigeaki
Published: November 2017

The crystal growth of single-crystalline Si1−xSnx layers with various Sn contents and analytical comparisons of their fundamental physical properties are strongly desired for next-generation group-IV electronics. In the present study, Si1−xSnx layers with varying Sn contents (1%−40%) were grown on various substrates [(001)-oriented Si, Ge, or InP] by solid-phase epitaxy. Crystallographic and composition analyses indicated that the grown Si1−xSnx layers were nearly lattice-matched to the substrates. When grown on Si, Ge, and InP substrates, the substitutional Sn contents were ∼1%, ∼20%, and ∼40%, respectively. Hard X-ray photoelectron spectroscopy revealed a valence-band offset resulting from the Sn substitution. The offset exhibited an upward-bowing tendency when plotted against the Sn content. The Si0.78Sn0.22/n-type Ge junction displayed rectifying diode characteristics with the ideality factor of 1.2.
Simulations of Coulomb systems confined by polarizable surfaces using periodic Green functions
Authors: dos Santos Alexandre P. , Girotto Matheus , Levin Yan
Published: November 2017

We present an efficient approach for simulating Coulomb systems confined by planar polarizable surfaces. The method is based on the solution of the Poisson equation using periodic Green functions. It is shown that the electrostatic energy arising from the surface polarization can be decoupled from the energy due to the direct Coulomb interaction between the ions. This allows us to combine an efficient Ewald summation method, or any other fast method for summing over the replicas, with the polarization contribution calculated using Green function techniques. We apply the method to calculate density profiles of ions confined between the charged dielectric and metal surfaces.
Vanishing characteristic speeds and critical dispersive points in nonlinear interfacial wave problems
Authors: Ratliff Daniel J.
Published: November 2017

Criticality plays a central role in the study of reductions and stability of hydrodynamical systems. At critical points, it is often the case that nonlinear reductions with dispersion arise to govern solution behavior. By considering when such models become bidirectional and lose their initial dispersive properties, it will be shown that higher order dispersive models may be supported in hydrodynamical systems. Precisely, this equation is a two-way Boussinesq equation with sixth order dispersion. The case of two layered shallow water is considered to illustrate this, and it is reasoned why such an environment is natural for such a system to emerge. Further, it is demonstrated that the regions in the parameter space for nontrivial flow, which admit this reduction, are vast and in fact form a continuum. The reduced model is then numerically simulated to illustrate how the two-way and higher dispersive properties suggest more exotic families of solitary wave solutions can emerge in stratified flows.
Note: Wide-operating-range control for thermoelectric coolers
Authors: Peronio P. , Labanca I. , Ghioni M. , Rech I.
Published: November 2017

A new algorithm for controlling the temperature of a thermoelectric cooler is proposed. Unlike a classic proportional-integral-derivative (PID) control, which computes the bias voltage from the temperature error, the proposed algorithm exploits the linear relation that exists between the cold side’s temperature and the amount of heat that is removed per unit time. Since this control is based on an existing linear relation, it is insensitive to changes in the operating point that are instead crucial in classic PID control of a non-linear system.
Large and reversible inverse magnetocaloric effect in Ni48.1Co2.9Mn35.0In14.0 metamagnetic shape memory microwire
Authors: Qu Y. H. , Cong D. Y. , Chen Z. , Gui W. Y. , Sun X. M. , Li S. H. , Ma L. , Wang Y. D.
Published: November 2017

High-performance magnetocaloric materials should have a large reversible magnetocaloric effect and good heat exchange capability. Here, we developed a Ni48.1Co2.9Mn35.0In14.0 metamagnetic shape memory microwire with a large and reversible inverse magnetocaloric effect. As compared to the bulk counterpart, the microwire shows a better combination of magnetostructural transformation parameters (magnetization difference across transformation ΔM, transformation entropy change ΔStr, thermal hysteresis ΔThys, and transformation interval ΔTint) and thus greatly reduced critical field required for complete and reversible magnetic-field-induced transformation. A strong and reversible metamagnetic transition occurred in the microwire, which facilitates the achievement of large reversible magnetoresponsive effects. Consequently, a large and reversible magnetic-field-induced entropy change ΔSm of 12.8 J kg−1 K−1 under 5 T was achieved in the microwire, which is the highest value reported heretofore in Ni-Mn-based magnetic shape memory wires. Furthermore, since microwires have a high surface/volume ratio, they exhibit very good heat exchange capability. The present Ni48.1Co2.9Mn35.0In14.0 microwire shows great potential for magnetic refrigeration. This study may stimulate further development of high-performance magnetocaloric wires for high-efficiency and environmentally friendly solid-state cooling.
Micromagnetic simulations of magnetoelastic spin wave excitation in scaled magnetic waveguides
Authors: Duflou Rutger , Ciubotaru Florin , Vaysset Adrien , Heyns Marc , Sorée Bart , Radu Iuliana P. , Adelmann Christoph
Published: November 2017

We study the excitation of spin waves in scaled magnetic waveguides using the magnetoelastic effect. In uniformly magnetized systems, normal strains parallel or perpendicular to the magnetization direction do not lead to spin wave excitation since the magnetoelastic torque is zero. Using micromagnetic simulations, we show that the nonuniformity of the magnetization in submicron waveguides due to the effect of the demagnetizing field leads to the excitation of spin waves for oscillating normal strains both parallel and perpendicular to the magnetization. The excitation by biaxial normal in-plane strain was found to be much more efficient than that by uniaxial normal out-of-plane strain. For narrow waveguides with a width of 200 nm, the excitation efficiency of biaxial normal in-plane strain was comparable to that of shear strain.
High performance broadband photodetector based on MoS2/porous silicon heterojunction
Authors: Dhyani Veerendra , Dwivedi Priyanka , Dhanekar Saakshi , Das Samaresh
Published: November 2017

A high speed efficient broadband photodetector based on a vertical n-MoS2/p-porous silicon heterostructure has been demonstrated. Large area MoS2 on electrochemical etched porous silicon was grown by sulphurization of a sputtered MoO3 thin film. A maximum responsivity of 9 A/W (550–850 nm) with a very high detectivity of ∼1014 Jones is observed. Transient measurements show a fast response time of ∼9 μs and is competent to work at high frequencies (∼50 kHz). The enhanced photodetection performance of the heterojunction made on porous silicon over that made on planar silicon is explained in terms of higher interfacial barrier height, superior light trapping property, and larger junction area in the MoS2/porous silicon junction.
Influence of the transition region between p- and n-type polycrystalline silicon passivating contacts on the performance of interdigitated back contact silicon solar cells
Authors: Reichel Christian , Müller Ralph , Feldmann Frank , Richter Armin , Hermle Martin , Glunz Stefan W.
Published: November 2017

Passivating contacts based on thin tunneling oxides (SiOx) and n- and p-type semi-crystalline or polycrystalline silicon (poly-Si) enable high passivation quality and low contact resistivity, but the integration of these p+/n emitter and n+/n back surface field junctions into interdigitated back contact silicon solar cells poses a challenge due to high recombination at the transition region from p-type to n-type poly-Si. Here, the transition region was created in different configurations—(a) p+ and n+ poly-Si regions are in direct contact with each other (“pn-junction”), using a local overcompensation (counterdoping) as a self-aligning process, (b) undoped (intrinsic) poly-Si remains between the p+ and n+ poly-Si regions (“pin-junction”), and (c) etched trenches separate the p+ and n+ poly-Si regions (“trench”)—in order to investigate the recombination characteristics and the reverse breakdown behavior of these solar cells. Illumination- and injection-dependent quasi-steady state photoluminescence (suns-PL) and open-circuit voltage (suns-Voc) measurements revealed that non-ideal recombination in the space charge regions with high local ideality factors as well as recombination in shunted regions strongly limited the performance of solar cells without a trench. In contrast, solar cells with a trench allowed for open-circuit voltage (Voc) of 720 mV, fill factor of 79.6%, short-circuit current (Jsc) of 41.3 mA/cm2, and a conversion efficiencies (η) of 23.7%, showing that a lowly conducting and highly passivating intermediate layer between the p+ and n+ poly-Si regions is mandatory. Independent of the configuration, no hysteresis was observed upon multiple stresses in reverse direction, indicating a controlled and homogeneously distributed breakdown, but with different breakdown characteristics.
Proximity and Josephson effects in microstructures based on multiband superconductors (Review Article)
Authors: Yerin Y. , Omelyanchouk A. N.
Published: November 2017

Emerging in the 1950s, the multiband superconductivity has been considered for a long time as an approximate model in the form of a generalization of the BCS theory to the case of two bands for a more accurate quantitative description of the properties and characteristics of such superconductors as cuprates, heavy fermions compounds, metal boron carbides, fullerides, strontium ruthenate etc. due to their complex piecewise-continuous Fermi surfaces. However the discovery of the multiband structure of the superconducting state in magnesium diboride in 2001 and iron oxypnictides and halides in 2008 led to the appearance of many papers in which effects and different dependences well known for usual one-band s-wave superconductors were re-examined. The main purpose of these studies was to reveal the symmetry type of the order parameter, which provides an important information about the mechanism of Cooper pairing in these superconductors. One of the most effective methods of obtaining information on the symmetry properties of the order parameter in the multiband superconductors is phase-sensitive techniques. This review summarizes the results of theoretical and experimental studies of the proximity and Josephson effects in systems based on multiband superconductors in contact with normal metals, insulators and other superconductors.
Lattices of SnTe surface nanoclusters on glass-ceramic
Authors: Saliy Ya. P. , Bushkov N. I. , Bylina I. S.
Published: November 2017

This is a study of atomic force microscope images of crystalline SnTe condensed on a ceramic glass (sitall) substrate. For the first time, two-dimensional forward and reverse Fourier transforms over the intense frequencies are used sequentially to analyze the data. A hidden periodicity in the position of objects on the surface of the film is discovered and confirmed by the two-dimensional autocorrelation function of the image. The one-dimensional Fourier transform is applied to the distribution of the azimuthal angle of the normal vector to the surface. It is found that the condensate surface has an invariant set of symmetry elements, although the dimensions of the surface objects depend monotonically on the deposition time. An approximation is obtained for the distribution of the polar angle of the normal vector using a unique single-mode function whose form is independent of the deposition time.
Simulations of viscoelastic fluids using a coupled lattice Boltzmann method: Transition states of elastic instabilities
Authors: Su Jin , Ma Lei , Ouyang Jie , Feng Chunjuan
Published: November 2017

Elastic instabilities could happen in viscoelastic flows as the Weissenberg number is enlarged, and this phenomenon makes the numerical simulation of viscoelastic fluids more difficult. In this study, we introduce a coupled lattice Boltzmann method to solve the equations of viscoelastic fluids, which has a great capability of simulating the high Weissenberg number problem. Different from some traditional methods, two kinds of distribution functions are defined respectively for the evolution of the momentum and stress tensor equations. We mainly aim to investigate some key factors of the symmetry-breaking transition induced by elastic instability of viscoelastic fluids using this numerical coupled lattice Boltzmann method. In the results, we firstly find that the ratio of kinematical viscosity has an important influence on the transition of the elastic instability; the transition between the single stationary and cycling dominant vortex can be controlled via changing the ratio of kinematical viscosity in a periodic extensional flow. Finally, we can also observe a new transition state of instability for the flow showing the banded structure at higher Weissenberg number.
Communication: Symmetry-adapted perturbation theory with intermolecular induction and dispersion energies from the Bethe–Salpeter equation
Authors: Holzer Christof , Klopper Wim
Published: November 2017

A method for calculating intermolecular induction and dispersion energies based on a GW description of the monomers and employing response functions from the Bethe–Salpeter equation is proposed. Calculations on a test set of 10 weakly bound complexes with GW-based symmetry-adapted perturbation theory (GW-SAPT) show an improved performance in comparison with symmetry-adapted perturbation theory based on density-functional theory (DFT-SAPT).
The magnitude of the intrinsic rate constant: How deep can association reactions be in the diffusion limited regime?
Authors: Vijaykumar Adithya , ten Wolde Pieter Rein , Bolhuis Peter G.
Published: November 2017

Intrinsic and effective rate constants have an important role in the theory of diffusion-limited reactions. In a previous paper, we provide detailed microscopic expressions for these intrinsic rates [A. Vijaykumar, P. G. Bolhuis, and P. R. ten Wolde, Faraday Discuss. 195, 421 (2016)], which are usually considered as abstract quantities and assumed to be implicitly known. Using these microscopic expressions, we investigate how the rate of association depends on the strength and the range of the isotropic potential and the strength of the non-specific attraction in case of the anisotropic potential. In addition, we determine the location of the interface where these expressions become valid for anisotropic potentials. In particular, by investigating the particles’ orientational distributions, we verify whether the interface at which these distributions become isotropic agrees with the interface predicted by the effective association rate constant. Finally, we discuss how large the intrinsic association rate can become, and what are the consequences for the existence of the diffusion limited regime.
An efficient multi-scale Green’s function reaction dynamics scheme
Authors: Sbailò Luigi , Noé Frank
Published: November 2017

Molecular Dynamics-Green’s Function Reaction Dynamics (MD-GFRD) is a multiscale simulation method for particle dynamics or particle-based reaction-diffusion dynamics that is suited for systems involving low particle densities. Particles in a low-density region are just diffusing and not interacting. In this case, one can avoid the costly integration of microscopic equations of motion, such as molecular dynamics (MD), and instead turn to an event-based scheme in which the times to the next particle interaction and the new particle positions at that time can be sampled. At high (local) concentrations, however, e.g., when particles are interacting in a nontrivial way, particle positions must still be updated with small time steps of the microscopic dynamical equations. The efficiency of a multi-scale simulation that uses these two schemes largely depends on the coupling between them and the decisions when to switch between the two scales. Here we present an efficient scheme for multi-scale MD-GFRD simulations. It has been shown that MD-GFRD schemes are more efficient than brute-force molecular dynamics simulations up to a molar concentration of 102 μM. In this paper, we show that the choice of the propagation domains has a relevant impact on the computational performance. Domains are constructed using a local optimization of their sizes and a minimal domain size is proposed. The algorithm is shown to be more efficient than brute-force Brownian dynamics simulations up to a molar concentration of 103 μM and is up to an order of magnitude more efficient compared with previous MD-GFRD schemes.
Student perceptions of the classroom learning environment and motivation to learn Chinese
Authors: Ji Chongmin , Duffield Stacy , Wageman Justin J. , Welch Anita G.
Published: November 2017

This study investigated the associations between student perceptions of their classroom psychosocial learning environment and their motivation to learn Mandarin Chinese in the United States. The students took two surveys that measured their perception of the Chinese classroom psychosocial learning environment and their motivation to learn Chinese. Descriptive and inferential statistics were used to analyze the data. There were statistically significant associations between student perception and motivation for learning the Chinese language. The three scales of Task Orientation, Involvement, and Equity emerged as having the most influence on students’ motivation to learn Chinese. The Task Orientation scale had the strongest relationship with student motivation.
Chinese language learners’ anxiety toward chat partners in computer-mediated communication
Authors: Wang Yanlin , Crooks Steven M. , Borst Stefanie
Published: November 2017

Studies have shown foreign language anxiety (FLA) can negatively impact learners’ performance in the classroom, but learners experience less FLA during computer-mediated communication (CMC) activities. Although it has been documented that communicating with native speakers (NSs) can make foreign language learners more anxious, very few empirical studies have compared learners’ anxiety levels toward different online chat partners. The current study investigated intermediate Chinese language learners’ FLA in online text CMC activities chatting with NSs and non-native speakers (NNSs). The quantitative data analyses showed that there was a significant difference in the anxiety level between chatting with NSs and NNSs in text-based CMC: chatting with NSs made Chinese learners more anxious than chatting with NNSs. Language confidence and partner familiarity were the two main factors mediating the anxiety. Practical pedagogical implications and future research directions were discussed.
试析师生性格特征与口头纠正性反馈之间的关系
Authors: Sun Peijian
Published: November 2017

口头纠正性反馈包括直接更正、元语言反馈、重铸、要求澄清、重复错误和诱导这六种方式。大量研究表明口头纠正性反馈对学习者语言能力的提升具有积极作用。性格特征，作为一个人的心理认同，具有相对稳定的特性，尤其就成年人而言。众多研究表明性格特征能够影响一个人第二语言的习得。然而，口头纠正性反馈与性格特征之间的关系却未能引起广泛重视。本文通过问卷调查、课堂录音和个别访谈三种方式考察了师生性格特征与口头纠正性反馈之间的关系。研究结果表明：（1）性格特征在一定程度上会影响教师口头纠正性反馈的纠错力度，但并不影响教师对不同类型偏误所持的纠错态度及反馈方式的总体选择。（2）师生就口头纠正性反馈方式所持的态度不尽相同，尤其在“直接更正”、“重铸”和“重复错误”方式上。（3）不同性格特征的教师和学生在口头纠正性反馈的选择上所持态度存在一定差异，尤其在“直接更正”、“元语言反馈”、“重铸”和“诱导”方面。
Protistan parasites and Myxozoa.
Authors: Rohde K.
Published: November 2017

Coverage of 'lower' organisms in this book is restricted to protistan and metazoan parasites and excludes fungi and other organisms such as bacteria and viruses, many of which are parasitic. The boundary between fungi and protistans is not well-defined. Protistan taxonomy, based on molecular phylogeny, is continually changing. For example, the Sarcomastigophora (still treated as such in this chapter), has disintegrated into many separate, high ranking taxa. Among them, the Opalinata belongs to a class of Heterokonta, these themselves are a subphylum of the phylum Chromista. This chapter includes groups that have commonly been considered to be protistan. It also includes the Myxozoa, which have the appearance of protistans and were for a long time considered to belong to that group. Recent DNA and ultrastructural studies have shown that they are metazoan, although their exact position within the metazoans has not been resolved. Like the Cnidaria, they possess nematocysts (or nematocyst-like structures), but molecular evidence points to a position among the bilaterian metazoan. All the groups discussed in this chapter have considerable importance as agents of disease, particularly in aquacultured fish and molluscs. Some of them, in particular the Microsporidia and Apicomplexa, are important as infective agents in immunocompromised people. Species richness is practically unknown for Sarcomastigophora, Microsporidia, Ciliophora and Myxozoa: new species are being described continually. In Australia, for example, <5% of the thousands of fish species have been examined for these parasites, and sample sizes of those which have been examined, were small. Fish of African, South American and many Asian countries have been examined even less. It may well be that these parasites belong to the most speciose groups of parasites in the marine environment and, as such, have considerable ecological importance. Also, at least some of the vast number of marine invertebrates that are yet to be examined are likely to have protistan parasites, probably including large numbers of sarcomastigophorans and ciliophorans. In view of the great morphological and taxonomic diversity of the protistans, this chapter begins with a brief overview of this kingdom before proceeding to the various sections dealing with the groups in greater detail.
Helminth parasites.
Authors: Rohde K.
Published: November 2017

Helminths (parasitic worms) are among the most important groups of marine parasites. They include some turbellarians (most of which are free living), ectoparasitic flukes (Monogenea), endoparasitic flukes (Aspidogastrea and Digenea), the various cestodes including the Amphilinidea, Gyrocotylidea and Eucestoda, nematodes (roundworms) and acanthocephalans (spiny-headed worms). Species numbers of some of these groups are enormous. Only a small proportion of the trematodes and monogeneans, for example, has been described, but total species number of these two groups has been estimated to be many tens of thousands. Many species have great ecological and economic importance. Monogeneans are known to do much damage to fish in aquaculture, and some cases of mass mortalities in the sea caused by monogeneans have been documented. Monogeneans, jointly with the copepods, are the most diverse group of ectoparasites of fish, as are the digeneans among the endoparasites. Digeneans are by far the most diverse group of metazoan endoparasites of fish and have evolved life cycles ranging from fairly simple to extremely complex. Nematodes are important parasites of many groups of marine animals including fish, marine mammals, birds and invertebrates. Some marine helminths have considerable theoretical interest. The Aspidogastrea, for example, are believed to be very ancient, hundreds of millions of years old, with many archaic characteristics. They may cast light on the evolution of parasitism in the trematodes. Acanthocephala are useful as pollution monitors: they accumulate certain pollutants at a much higher rate than their hosts. Parasitism in the turbellarians has arisen several times, some living in the intestine, others in the tube feet of echinoderms, and others again on the gills of marine fish. Adaptations to their way of life vary considerably, making them fascinating objects of study in what may be called comparative parasitology. The eucestodes, discussed in a beautifully illustrated section, are important parasites in the digestive tract especially of elasmobranchs, with a whole spectrum of remarkable morphological adaptations of their attachment organs, and some with extremely complex life cycles.
Coevolution and speciation.
Authors: Rohde K.
Published: November 2017

Marine parasites have not ranked highly as evolutionary models. The only evolutionary aspect of marine parasites that has been studied in greater detail is coevolution. Much effort has gone into comparing evolution of some marine host groups, in particular various fishes, seabirds, and mammals, and of their parasites. The very detailed discussion of coevolution discusses these examples, but also points out that much work remains to be done: for most host and parasite taxa, information necessary to make inferences about coevolutionary patterns is insufficient. Much less is known about mechanisms of speciation. The author of the section on speciation and species delimitation stresses the importance of understanding what species are. Such understanding is a prerequisite for addressing fundamental questions about biological processes and biodiversity. Various ways to delimit species are discussed, as are the few examples of studies of species delimitation and speciation in marine parasites.
Zoogeography.
Authors: Rohde K.
Published: November 2017

This chapter reviews evidence for gradients not only in marine parasite diversity, but also for gradients in reproductive strategies, host specificity and latitudinal ranges. Concerning gradients with depth, relative species diversity of monogeneans is several times greater in surface than in deep waters off eastern Australia. Parasites can be used to study host populations and their migration, not only of marine fish but also of various invertebrates. Such parasite tags are much cheaper than other methods, such as comparative genetic studies, as discussed (on pages 351-355). The section discusses general methodology, selection criteria for tag parasites and application of the method to different host groups (crustaceans, cephalopods, pelagic fish, demersal fish, marine mammals). Parasites also are useful for making inferences about long-term historical dispersal. The relevant section describes the only 2 examples studied (i.e. that of scombrid dispersal with emphasis on the role of oceanic barriers, and that on the historical migrations of Indo-Pacific whiting, Sillaginidae). The section on introduced marine parasites (e.g. protozoan parasites, monogeneans, trematodes, nematodes, polychaetes, copepods, rhizocephalans) addresses a very important problem (i.e. that of the many parasites introduced into new regions, where they have become important pests). It also discusses the use of deliberately introduced parasites to control introduced free-living pest species, such as crabs or echinoderms. The chapter concludes with a concise discussion of deep-sea parasites. Very little is known about the diversity and distribution of free-living deep-sea organisms (probably more than 99% of invertebrates have not yet been described), and deep-sea parasites have been studied even less. They are of great importance, considering the huge spaces of the deep-seas, and the many species of fish and invertebrates found there.
Economic and environmental importance.
Authors: Rohde K.
Published: November 2017

Almost all (if not all) groups of marine animals including the various invertebrates and vertebrates are hosts to parasites. Parasites of these groups have been discussed by various authors in the four volumes edited by Kinne (1980-1985). This chapter is restricted to discussions of parasitic infections of the more important groups. Marine parasites are of very great ecological importance, as suggested by their great diversity, and by their often high prevalences and intensities of infection. However, very little is known about how they affect host populations in the oceans. An exception is the long-term study of salmon lice on Atlantic salmon not only in aquaculture but also in wild salmon populations, conducted because of the great economic importance of salmon. Mass mortalities caused by parasites have not been well documented for marine fish and invertebrates because of the large spaces in the oceans involved and the difficulties in monitoring such effects. Effects on marine birds are little understood and need much further study: mass mortalities of seabirds have been attributed to several causes but parasite examinations which could have revealed the role of parasites in the mortalities were not conducted. Effects on mammals such as whales are well documented, and hundreds of parasite species of mammals have been described; nevertheless, much needs to be done in this area as well. Much greater effort has gone into the study of parasite diseases in aquaculture, which is not surprising in view of the enormous and rising economic value of aquacultured fish, molluscs and crustaceans, estimated at many billions (109) of dollars annually. For example, the commercial value of cultured salmonid fishes alone in 2001 was around US$3.84 billion (US$7.44 billion for all finfish). Disease, and much of it resulting from parasites, is the single most important factor threatening the aquaculture industry. Beside these important negative aspects of marine parasites, this chapter also discusses a more positive aspect of parasites: the use of parasites in pollution monitoring. Pollution may affect the composition of parasite communities, and some parasites store certain pollutants to a higher degree than their hosts; both these phenomena can be used for monitoring pollution.
Agriculture as a producer of energy.
Authors: Eidman V. R.
Published: November 2017

This chapter documents the role agriculture is playing as a supplier of energy for the US economy and discusses the potential contributions agriculture can make to the nation's energy supply in the near future. More specifically, this chapter (1) documents the amount of energy used by the US economy and agriculture's role in supplying it; (2) discusses the current state of technology in energy production from agricultural biomass; (3) summarizes some recent literature on the potential contribution agriculture can make to the US energy supply; and (4) provides a brief overview of the developing ethanol and biodiesel industries in other countries.
Energy systems integration: fitting biomass energy from agriculture into US energy systems.
Authors: Doering O. C., III
Published: November 2017

This chapter explores the prospects of biomass from agriculture as an increased component of the US national energy use. It examines: (1) the extent to which biomass sources and systems can meet the form, time, and place determinants of energy utility that consumers obtain from current sources and systems; (2) the compelling reasons for current energy sources and systems to predominate that tie them to consumers and may discourage their replacement by other systems and sources; (3) how biomass energy might be successfully integrated into current systems and the critical challenges in doing this; and (4) the policy issues that have to be dealt with for biomass sources to integrate or successfully create replacements for existing energy systems.
US oil and gas markets: a scenario for future strong inter-fuel competition.
Authors: Lindemer K. J.
Published: November 2017

This chapter looks at the volatility in both the world oil and North American natural gas markets. It is suggested that despite the greater degree of volatility, both markets appear set to remain at higher price levels for the foreseeable future. While oil prices are likely to recede from the recent very high levels experienced in 2004, North American natural gas prices are likely to remain much higher than the prices experienced prior to 2000 and higher relative to oil prices. It is argued that the emerging price dynamic between oil and natural gas in North America will reshape the demand for oil and gas and potentially have an important impact on the future energy market in the USA. Implications for the agricultural industry are also briefly discussed.
Dry-mill ethanol plant economics and sensitivity.
Authors: Tiffany D. G. , Eidman V. R.
Published: November 2017

In an attempt to address the numerous factors that influence the operational and financial success of dry-mill fuel ethanol plants in the USA, a spreadsheet was developed that can be used by potential investors in ethanol production, those planning new operations, or managers evaluating their financial impacts or improving an existing plant's performance. This chapter reviews the design features of the spreadsheet and the rationale for that design. An application of the spreadsheet is also presented. The spreadsheet was used to determine the economic returns for a modern 40-million-gal/year plant with current scale economies, investment costs and enhanced ethanol yields in its first year of operation by re-playing a decade of historic prices for products and inputs. The model demonstrates that even a well-located plant will experience times of difficult operating conditions and gross margins.
An econometric analysis of the impact of the expansion in the US production of ethanol from maize and biodiesel from soybeans on major agricultural variables, 2005-2015.
Authors: Ferris J. N. , Voshi S. V.
Published: November 2017

This chapter provides an analysis of the possible effects on agriculture of alternative scenarios for programmes that encourage the expansion of ethanol and biodiesel production in the USA. The analysis focuses on comparisons of scenarios with baselines over the 2006-15 projection period. It is concluded that expansion in the use of maize for ethanol and soyabeans for biodiesel can be accommodated without major increases in acreages or disruptions in the normal pattern of utilization of these crops. Higher maize and soyabean prices will have minimal impacts on retail food prices. Most notable will be larger supplies of maize by-product feeds for domestic use and export. It is suggested that renewable fuel programmes can help ensure an economically viable agriculture and minimize federal farm programme costs, benefits which will be even more pronounced if maize and soyabean prices are lower than projected in the baseline.