bluuebunny/crossref_metadata_2025 huggingface dataset:
Exploring the biases of a new method based on minimum variance for interplanetary magnetic clouds
Authors: Démoulin P. , Dasso S. , Janvier M.
Published: September 2018

Context. Magnetic clouds (MCs) are twisted magnetic structures ejected from the Sun and probed by in situ instruments. They are typically modeled as flux ropes (FRs).

Aims. Magnetic field measurements are only available along the 1D spacecraft trajectory. The determination of the FR global characteristics requires the estimation of the FR axis orientation. Among the developed methods, the minimum variance (MV) is the most flexible, and features only a few assumptions. However, as other methods, MV has biases. We aim to investigate the limits of the method and extend it to a less biased method.

Methods. We first identified the origin of the biases by testing the MV method on cylindrical and elliptical models with a temporal expansion comparable to the one observed in MCs. Then, we developed an improved MV method to reduce these biases.

Results. In contrast with many previous publications we find that the ratio of the MV eigenvalues is not a reliable indicator of the precision of the derived FR axis direction. Next, we emphasize the importance of the FR boundaries selected since they strongly affect the deduced axis orientation. We have improved the MV method by imposing that the same amount of azimuthal flux should be present before and after the time of closest approach to the FR axis. We emphasize the importance of finding simultaneously the FR axis direction and the location of the boundaries corresponding to a balanced magnetic flux, so as to minimize the bias on the deduced FR axis orientation. This method can also define an inner flux-balanced sub-FR. We show that the MV results are much less biased when a compromize in size of this sub-FR is achieved.

Conclusions. For weakly asymmetric field temporal profiles, the improved MV provides a very good determination of the FR axis orientation. The main remaining bias is moderate (lower than 6°) and is present mostly on the angle between the flux rope axis and the plane perpendicular to the Sun–Earth direction.
Experimental research of beams with corrugated web
Authors: Zubkov Vladimir , Lukin Alexey , Alpatov Vadim
Published: September 2018

The paper presents an experimental methodology, measuring instruments, equipment and results of an experimental study of beams with corrugated sinusoidal-shaped web. It also investigates the influence of parameters on the beams load bearing capacity. The researchers obtained data on critical loads and types of the extreme limit state at action of concentrated forces with various width of a load transmission section. They also assessed load bearing capacity of beams with different length and section height when work according to single-span jointed scheme.
Thin-walled profiles and their joint assembly units built with screws: numerical studies of load bearing capacity
Authors: Alpatov Vadim , Soloviev Alexey
Published: September 2018

There is a tendency to reduce weight of load-bearing metal structures being developed and successfully realized in modern building construction. This idea serves as a basis for a whole scientific direction, named Development and application of light steel thin-walled structures (LSTS). Among them, LTST built with pop-rivets and thread-cutting screws are most widespread due to their simplicity and relative cheapness This paper presents numerical studies of LSTS joint assembly units built with screws and their load bearing capacity. The peculiarity of these units consists in misalignment of joint elements. The calculation was performed in the SolidWorks Simulation System. The modeled node is a three-dimensional assembly consisting of solid components. The results of the study are as follows: 1) thin-walled profiles have a significant sensitivity to eccentricity; 2) it is unacceptable to disregard eccentricities for thin-walled profiles and their joint connections; 3) eccentricities should be compensated by measures to improve reliability in joint connections design.
Determination of physic and mechanical parameters of high-density polyethylene based on relaxation curves due to the presence of hydroxyapatite and ionizing radiation
Authors: Litvinov Stepan , Yazyev Serdar , Vysokovsky Dmitriy
Published: September 2018

Relatively low physical and mechanical parameters of polymers negatively affect the possibility of using this material everywhere. There are ways to improve the elastic and rheological characteristics of some varieties of polymers: addition of additives and irradiation with ionizing radiation. However, these methods can lead both to the cross-linking of polymer molecules with the improvement of its parameters, and to its destruction. In this article shown the theoretical definition of physic and mechanical parameters of high-density polyethylene by known stress relaxation curves, and a comparison of the experimental data of high-density polyethylene (HDPE) with the data obtained theoretically, which, in turn, saves material resources and man-hours for the experiment and its subsequent analysis.
Performance of a Suspension Bridge with Active Vibration Dampers
Authors: Konovalov Anatolij , Pustovalova Marina
Published: September 2018

Suspended structures that are used extensively in construction of motorway and pedestrian bridges allow bridging wide spans without having to install intermediate supports. Being less stiff in comparison to girder and arch bridges, suspension bridges require their dynamic properties to be controlled [1, 2]. This is a vital task when it comes to suspension bridges. Several engineering arrangements are available to control the dynamic properties of the structures [3]. This paper addresses the use of active dampers [4] installed on the tops of the towers as the means to control vibrations of a suspension bridge. To this end, a planar 3D model of suspension bridge was built using ANSYS software. The authors compared stress-strain behavior and dynamic properties of the models with and without active vibration dampers. In contrast to the initial model, the model of a bridge equipped with active dampers exhibits less displacement in all cross-sections. Thus, the displacements are reduced 1.7 times in the middle of the central span of suspended stiffening truss; 2.7 times in the middle of the end span; and displacements of the top of the bridge tower are 1.6 times less. The modal analysis has shown that in the model with active dampers the frequency of transverse vibrations at the tower tops has increased 1.9 times, while vertical vibrations have increased within 23%. Under maximum applied overpressure in the active damper, torsional vibrations of the structure have increased 2.4 times as compared to the initial model. The results obtained by the authors allow for the conclusion that active dampers are useful tools for controlling the dynamic properties of a suspension bridge.
Computational models of reinforced concrete ribbed floor
Authors: Czumaj Przemysław , Dudziak Sławomir , Kacprzyk Zbigniew
Published: September 2018

This paper describes differences between models of a rectangular shaped reinforced concrete floor with ribs, commonly used by structural designers. Comparison analysis proves significant differences in result obtained from different models. Incompatibility is shown both in static as well as in modal analysis.
Simulation of vibrations of a continuously elastic supported rod with varying boundary conditions under the action of a movable
Authors: Gridnev Sergey , Skalko Yuriy , Ravodin Ilya , Yanaeva Victoria
Published: September 2018

To simulate the non-linear vibrations of a floating bridge of a continuous system on separate floating supports with additional limiting supports at the ends with a moving load solves the most complicated problem which is the problem of describing the behavior of a span structure. A technique for simulating the vibration of an elastically supported deformable rod with limiting supports at the ends, which is a design scheme of a span structure, under the action of a moving force is developed. A computational algorithm for solving partial differential equations with varying boundary conditions is proposed, which includes boundary conditions in the model equations and does not require the subordination of basis functions to the boundary conditions. During the calculation, the basis remains constant. Piecewise linear basis functions are used to solve the differential equation. The technique is tested using a computational program Matlab, which is implemented when performing numerical studies of the behavior of the dynamic system as a function of the parameter changes. The developed technique is universal for studying the dynamics of a number of constructively non-linear systems.
Influence analysis of climate data time-step on the accuracy of HAM simulation
Authors: Juras Peter , Jurasova Daniela
Published: September 2018

Scientific research in the area of building simulations has a great potential and it is continuously developing and advancing. Computer simulations are helpful in many areas of Civil Engineering, such as energy demand, moisture transport, thermal comfort, ventilation etc. Climate data measured by experimental weather station are analyzed in this article. Weather station is located within the University campus and data recorded with a short are used in a non-steady heat-air-moisture simulation. Climate parameters differences caused by the various averaging periods are shown. This differences are also analyzed in term of outdoor surface temperatures calculated with WUFI Pro simulation software.
Numerical analysis of strengthening concrete columns by high performance fibre concrete
Authors: Vavruš Martin , Koteš Peter , Tamrazyan Ashot
Published: September 2018

Concrete is a material that has advantages and disadvantages. High strength in pressure, as well as increased mechanical resistance are its advantages, on the other side, it has a lower tensile strength as its disadvantage. This is related with creating cracks, when concrete in a tensile zone occurs plasticisation of reinforcement (provided that members are reinforced) which is in consequence of depletion carrying capacity associated with creating plastic hinge and exceed his rotation capacity. Following, the cross-section has a lower carrying capacity. Strengthening of jacketing by fibre-concrete has provided with reducing width of cracks an increasing of carrying capacity cross-section at minimal increasing of the columns slenderness.
Designing reinforced concrete slabs under fire condition
Authors: Maciąg Michał , Spodzieja Szymon
Published: September 2018

In this article the capacity of reinforced concrete slabs of thickness larger than 15 cm was calculated with Isotherm 500 Method. For designed elements were analysed the support and span zone. There have been proposed tables for designers, on which basis it is possible to design slab of demanded fire capacity.
Interaction of the pile with the sagging loess soil
Authors: Ter-Martirosyan Zaven , Luzin Ivan
Published: September 2018

The article presents the formulation and solution of the problem in the interaction of a pile with a two-layered base, the upper layer of which settles due to the moistening by the filtrational flow (Darcy's law) or moisture transfer (Fick's law), and the lower layer is bearing, possesses relatively strong and deformation properties, which pushes against.

It is shown that due to subsidence of the surrounding soil, negative friction occurs on the lateral surface of the pile, which causes additional draft and force at the level of the heel of the pile. As a calculation, the geomechanical model of the ground cylinder, containing the pile and perceiving the load from the grillage as part of the pile-slab foundation, is considered.
Lightweight concrete of continuous structure without fine aggregate
Authors: Chiknovoryan Alexandr , Mizuryaev Sergey , Zhigulina Anna
Published: September 2018

The study deals with basic properties and area of application of lightweight concrete of continuous structure without fine aggregate. When fine aggregate is excluded from the concrete structure, it becomes lightweight, has lower thermal conductivity and cost, simpler production technology. It also has durability sufficient for wall panels, water resistance, frost resistance and a number of other indicators. The paper describes additives used for concrete air entrainment. Using these additives does not complicate the production technology of panels, the panels can be easily transported and have sufficient stability and durability upon storage. The article justifies effective application of light concrete with continuous structure without fine aggregate in low-rise construction. Light concretes of continuous structure without fine aggregate allow to completely exclude the use of fine aggregate, to sharply reduce density and thermal conductivity of concrete, as well as to reduce moisture content and humidity of products, improve their cohesion and workability and get a number of other benefits. The study shows that light concrete without fine aggregate numerous advantages prove that it will be used in construction practice for a long time.
Complex characteristic for forecasting durability of hydraulic concrete
Authors: Popov Valeriy , Popov Dmitry , Davidenko Anna
Published: September 2018

The paper analyzes operating conditions of hydraulic structures, as well as the main types of external influence with temperature and humidity variations. The purpose of the research is to highlight the main parameters which will be able to assess the actual durability of concrete hydraulic structures in the process of their design. The authors use methods developed in Samara Architecture and Civil Engineering Institute to determine concrete physical and mechanical characteristics. Thus, these methods help accurately assess concrete durability, frost resistance and water resistance. These methods are based on theoretical studies of the processes of concrete destruction by means of non-destructive acoustic methods. The the energy conception developed by A.A. Griffits and S.N. Zhurkova's kinetic serve as a scientific basis for the methods. Theoretical research and its analysis of concrete destruction processes from various kinds of external influence was confirmed by results of standard measurements. The research showed that durability of concrete, that is speed of its destruction, depended on two groups of physical and mechanical characteristics. One of the groups evaluates the initial structure of concrete, while the second group characterizes the speed of the material loading . The paper proposes a forecasting method of frost resistance and water-resisting properties of concrete according to its physical-mechanical characteristics. It also introduces an indicator of their assessment which is named the length of the reduced crack. The proposed indicator has a good correlation with frost resistance and water-resisting properties . Besides, the proposed method can be used not only in laboratory conditions, but also in construction production directly on the construction site.
Studying penetrating ability of alkaline flow solution of caprolactam production in flint aggregate
Authors: Chumachenko Natalia , Kizilova Diana , Hafizov Ilnur
Published: September 2018

The study focuses on increasing the clinker formation degree of calculus types of siliceous rock. One of the ways to increase the flint aggregate strength is to saturate the surface layer of grains with alkaline ions. While calcining, this will provide formation of confining elements which are more caked than the inner layers. To preserve natural porosity inside granules and to increase density and durability of a surface layer, it is offered to process grains of dense siliceous rock before calcining them with a solution of alkaline flow of caprolactam production (AFCP). It is shown that the degree of density is determined by the soaking depth, which depends on the molecular structure of alkaline solution. The paper also demonstrates results of influence of processing conditions on soaking depth of grains with 10-15 mm fraction. The researchers studied the effect of AFCP solution concentration in the range varying from 3 to 20%. The duration of treatment ranged from 2 to 5 minutes. The research results are presented in the form of graphs. The optimal processing mode is also determined.
Raspberry PI 3B + microcomputer as a central control unit in intelligent building automation management systems
Authors: Sałuch Mateusz , Tokarski Daniel , Grudniewski Tomasz , Chodyka Marta , Nitychoruk JerzyAntoni , Woliński Paweł , Jaworska Beata , Adamczewski Grzegorz
Published: September 2018

This article aims to show the possible savings in electricity costs in smart building installations with the use of new version of Raspberry Pi 3 model B + as the control unit in intelligent building automation systems. It presents a comparison of the consumption of electricity in two units used in the central control systems, i.e. a small Windows-based computer and a Raspberry microcomputer. The power consumption of these units was measured during the rest period and during standard operations in the intelligent installation system. The conducted measurements proved that the use of the new updated version of Raspberry Pi 3 model B + as the central control unit in intelligent building management systems is more economical and energy-saving.
Study of the abrasion resistance of wood-polymer composites and mixtures of ABS-plastic with polyvinyl chloride
Authors: Matseevich Andrey , Matseevich Tatyana , Askadskii Andrey
Published: September 2018

The abrasion of materials based on blends of ABS plastic with polyvinyl chloride (PVC) as well as terraced boards based on wood-polymer composites (DPC) has been studied. The measurements were carried out on a drum-type machine, and on a Taber's abrasimeter. For blends of ABS plastic with PVC at abrasion path length 600 m wear is 0.85%. For terracotta boards based on WPC, the wear during the test (loss of mass) was 0.0042 g. The abrasion of the sample was 9.29×10-5 g/cm2. Thus, the obtained blends should be recommended for application for floor coverings, since they possess negligible abrasion.
The pollution prevention during the civil construction
Authors: Azarov Valery , Manzhilevskaya Svetlana , Petrenko Lubov
Published: September 2018

The environmental protection is not only an important social problem, but also an efficiency increasing factor of construction operations. The problem of the environment preserving and the protecting people from the adverse health effects during the construction operations is growing more urgent due to the increase in volume of construction and the increasing availability of construction equipment. The works of many researchers are devoted to the study of the dust load and the evaluation of influence on the environment.This article describes the practical effect of air pollution during the construction site landscaping of two buildings, which are situated in Rostov-on-Don. Nowadays the limitation of air pollution emissions from construction operations is regulated by a number of normative documents, but civil designers, unfortunately, do not always meet the regulation of emissions in full obedience in the construction operating for a number of reasons. The correct environmental impact assessment from construction is possible, taking into account the sequence and simultaneity of the operations. It is especially important for the construction taken place on the territory of cities. According to the study, a set of measures for air pollution reduction was developed. Such measures can reduce the air pollution by 1.5-2 times.
The effect of vibration on the possibility of a threat to the health of workers on scaffolding
Authors: Grosel Jacek , Sawicki Marek , Sawicki Wojciech , Szóstak Mariusz , Wójcicki Zbigniew
Published: September 2018

Scaffoldings are specific structures that are particularly predisposed to vibrations. The article analyses the impact of vibrations induced by human activity on the stage for the possibility of a threat to the health of workers working in these structures. The aim of the article is to present experimental research.
Modeling the influence of connecting elements in wood products behavior: a numerical multi-scale approach
Authors: Chevalier Luc , Makhlouf Heba , Jacquet-Faucillon Benoît , Launay Eric
Published: September 2018

Wood furniture is often composed of simple parts that may be modeled as beams or plates. These particularities allow using simplified approaches that reduces the number of degrees of freedom (dof for short) in a finite element simulation of the furniture's behavior. Generally, connections are not taken into account in such simulations but these connections are critical in the failure process of the furniture and it worth studying it precisely. Using a multi-scale approach, this paper introduces a numerical procedure to identify the connection contribution in the furniture's stiffness. Comparing 3D finite element calculations with a Timoshenko's beam calculation on a corner of two wooden parts, we identify the specific behavior of the connection elements (pins, nut, screw… and local 3D effects) to introduce it as a punctual 0D element in the beam code. Two validations of the approach are presented here: (i) a numerical validation by comparing the result of the beam code with a complete 3D finite element simulation on a representative plane structure of wooden furniture; (ii) an experimental validation by managing a global bending test and measuring the displacement field using digital image correlation (DIC for short).
Burnout bei Schülern – muss das sein?
Authors: Schulte-Markwort Michael , Wiegand-Grefe Silke
Published: September 2018

„Ich kann nicht mehr“, „Ich weiß nicht, wie ich das schaffen soll“, „Ich bin
erschöpft, traurig und mein Leben ist sinnlos geworden“ – das sind die
Sätze, die wir von Kindern und Jugendlichen in den letzten Jahren häufiger
hören. Sie befinden sich in einer verzweifelten Lage und wissen keinen
Ausweg, und ihre Eltern auch nicht. Noch ist es keine große Gruppe von
Patienten – aber wir sind gefordert, zu verhindern, dass es immer mehr
werden.
Räumliche und zeitliche Entgrenzung der Arbeit: Chancen,
Risiken und Beratungsansätze
Authors: Michel Alexandra , Wöhrmann Anne M.
Published: September 2018

Die Digitalisierung ermöglicht eine Entkoppelung der Arbeit von Zeit und Raum.
Orts- und zeitflexibles Arbeiten bietet Beschäftigten mehr Möglichkeiten, Beruf
und Privatleben zu vereinbaren. Es kann aber auch belastend sein und Gesundheit
sowie Wohlbefinden beeinträchtigen. Eine wichtige Rolle spielt die
Schnittstellengestaltung von Arbeit und Privatleben.
Was versteckt sich hinter Burnout?
Authors: Hillert Andreas
Published: September 2018

Burnout ist quasi in aller Munde. Das ist gut so, weil so die
individuellen und kollektiven Grenzen einer ansonsten ins Unendliche
projizierten Leistungsgesellschaft deutlich und kommunizierbar werden. Wenn mit
Burnout allerdings Diagnose-äquivalente Phänomene bezeichnet werden sollen, wird
es diffiziler. Charakterisiert das eindrückliche Bild – etwa eines ausgebrannten
Hauses – wirklich ein Stress-Phänomen?
Kramer and Chevron Osteotomy for Hallux Valgus Deformity – Retrospective Comparison of Functional and Radiological Results
Authors: Schulze Christoph , Böhme Nina , Hacke Claudia , Gutcke André , Bergschmidt Philipp
Published: September 2018

Hintergrund Der Hallux valgus ist mit einer Prävalenz bis zu 23% die häufigste Vorfußdeformität. Bei Beschwerden ist die Therapie operativ. Prospektive Studien, die Vorteile eines Verfahrens gegenüber einem anderen aufzeigen, sind selten. Bei Indikationen zur distalen Vorfußkorrektur gilt die Chevron-Osteotomie oft in Kombination mit einer Weichteilkorrektur als Therapie der Wahl. Der Stellenwert der OP nach Kramer ist nicht explizit beschrieben. Ziel der Untersuchung ist es, die funktionellen und radiologischen Ergebnisse beider OP-Verfahren zu vergleichen.

Material und Methoden In die retrospektive Untersuchung wurden 174 Patientendatensätze (42 männlich, 132 weiblich, 44,0 ± 16,8 Jahre) einbezogen, die zwischen 2008 und 2015 mit einer Chevron-Osteotomie (n = 71) oder Kramer-Osteotomie (n = 103) behandelt wurden. Die OP-Dauer wurde erfasst. Es erfolgte eine Auswertung der prä- und postoperativen Röntgenaufnahmen mit Bestimmung des Hallux-valgus-, des Intermetatarsalwinkels und der Sesambeinkonfiguration (Mittelwerte ± SD). Funktion und Lebensqualität wurden anhand des Foot and Ankle Outcome Score (FAOS) und EuroQol5D geprüft. Das Schmerzniveau wurde mittels numerischer Ratingskala (NRS) erfasst. Die statistische Auswertung erfolgte über mixed model ANOVA sowie t-Tests für unabhängige Stichproben.

Ergebnisse Beide Verfahren reduzierten den Hallux-valgus-Winkel (Kramer: 30 ± 8° auf 9 ± 7°; Chevron: 26 ± 7° auf 16 ± 9°; p < 0,001). Der Unterschied zwischen den Verfahren war statistisch signifikant (10 ± 2°; 95%-KI: − 12,93; − 6,49; p < 0,001). Beide Verfahren reduzierten den Intermetatarsalwinkel leicht (14 ± 3° auf 12 ± 3°; p < 0,001), jedoch ohne einen signifikanten Unterschied zwischen den Verfahren (p = 0,116). Die Sesambeinkonfiguration konnte durch die Kramer-Osteotomie signifikant von 2/2 auf 0/1 nach Appel verbessert werden (p < 0,001). Dies gelang mit der Chevron-Osteotomie nicht (2/2 auf 2/1; p = 0,052). Die OP-Dauer war bei der Kramer-OP im Vergleich zur Chevron-Osteotomie kürzer (31 ± 14 vs. 44 ± 12 min; p < 0,001). Ein Unterschied im postoperativen Schmerz- und Beschwerdeniveau konnte nicht nachgewiesen werden (NRS postoperativ Chevron: 1,3; Kramer: 1,7; p = 0,413; FAOS: keine signifikanten Unterschiede in den Kategorien ADL (activities of daily living), Sport, Lebensqualität, Funktion und Schmerz).

Schlussfolgerung Bei vergleichbaren funktionellen sowie besseren radiologischen Ergebnissen und kürzerer OP-Dauer ist die Kramer-OP eine mögliche Alternative zur Chevron-Osteotomie. Die Ergebnisse der vorliegenden Untersuchung müssen in prospektiven Studien bestätigt werden.
Reliability of an ice hockey-specific complex test
Authors: Schwesig René , Lauenroth Andreas , Schulze Stephan , Laudner Kevin , Bartels Thomas , Delank Karl , Reinhardt Lars , Kurz Eduard , Hermassi Souhail
Published: September 2018

Background This study assessed the intra-rater reliability of an ice hockey-specific complex test (IHCT) that reflects the intense multidirectional and intermittent efforts required in ice hockey.

Methods Twenty professional players executed the IHCT twice over an interval of 2 days. Load parameters included a 10-m sprint, a 30-m transition with and without a puck, as well as slap and wrist shots. Stress parameters were lactate concentrations and heart rates.

Results The intrarater reliability (ICC) ranged from 0.54 to 0.98 for load parameters, and from 0.26 to 0.87 for stress parameters. 33 % (3/9) of stress parameters and 82 % (18/22) of load parameters had an ICC > 0.75. The largest limits of agreement were 41.6 for slap shot 1 after test and 50.4 for 6-min heart rate recovery. The smallest were 0.40 (10-m sprint without a puck) and 5.36 (resting lactate). The intra-rater reliability as shown by the coefficient of variation (CV) was lower for stress than for load parameters (mean CV: 13.4 vs. 4.7). 68 % (15/22) of load parameters and 11 % (1/9) of stress parameters showed a CV below 5 %.

Conclusion The IHCT is currently the only ice hockey-specific complex test with scientifically tested reliability and validity that can analyze performance under conditions similar to competition. It is suggested that coaches, fitness coaches and sports scientists explore use of this test as a valid tool to assess players’ performance and the effectiveness of training interventions.
Preparation and Properties of a Hydrolytically Stable Cyclooctyne-Containing Polymer
Authors: Adronov Alex , Li Kelvin , McNelles Stuart
Published: September 2018

A poly[(phenylene vinylene)-co-dibenzocyclooctyne] polymer prepared by Wittig polymerization chemistry between dibenzocyclooctyne bisaldehyde [DIBO-(CHO)2] and bis(triethyleneglycol)phenylbis(tributylphosphonium) dibromide is reported. The resulting polymer exhibits moderate molecular weight (Mn: 10.5 kDa, Mw: 21.3 kDa, Ð: 2.02) and is fluorescent. It could be readily functionalized by strain-promoted alkyne-azide cycloadditon with different azides, and fluorescence of the polymer was preserved after functionalization. Grafting azide-terminated 5 kDa poly(ethylene glycol) monomethyl ether chains drastically affected the solubility of the polymer. Cross-linking the polymer with poly(ethylene glycol) that was terminated at both ends with azide groups gave access to a fluorescent organogel that could be dried and reswollen with water to form a hydrogel.
Task repetition for language learning
Authors: DeKeyser Robert M.
Published: September 2018

This chapter looks at task repetition in second language learning from the point of view of skill acquisition theory and related areas of psychology. It explores not only what concepts like procedural and declarative knowledge, automatization, and transfer have to offer the applied linguist, but also summarizes the literature on distribution of practice, interleaving versus blocking, and similarity in repeated practice, drawing on both the psychological and the fledgling second language acquisition (SLA) literature. In general, the literature shows support for distributed practice, for interleaving, and for variety in practice. For all these points there are exceptions, however, in particular in the SLA literature. This chapter discusses some of the possible explanations for these differences, and ends with some recommendations for where to focus future research: how automatization may vary with the domain of language, how distribution of practice may depend on whether the knowledge practiced is declarative or procedural in nature, and how research can help find the ideal context for bringing about transfer from one task to the other.
Discourse performance in L2 task repetition
Authors: Wang Zhan , Chen Gaowei
Published: September 2018

‘Repetition’ in language practice has often been associated with behavioristic drills, typically regarded as giving rise to habit formation, and often excluded from mainstream language teaching approaches. However, this study, drawing upon Bygate’s (1999) argument that task is a context for the framing and reframing of language, shows that repetition in meaningful tasks does not necessarily involve passive performance repetition; instead, L2 learners are actively re-constructing the narrative discourse. This study provides support to this argument through the analysis of the speech samples from thirteen learners performing an immediate exact L2 task repetition. The participants were asked to perform a video-based monologue story narration twice to an imagined listener, and the comparison of the learners’ first and second speech performances shows that the learners enhanced their discourse performance with: (1) increased quantity of discourse (evidenced by more Total Words, Total Propositions, and higher P-density); (2) increased cohesion (evidenced by higher ratio of given words to new words in sentences based on latent semantic analysis, i.e., LSA Given/New value); and (3) increased quality of lexis (evidenced by higher Noun Hyperonymy value, indicating more specific nouns used). The results suggest that task repetition, in addition to its effects on language complexity, accuracy, and fluency, has an impact on learners’ speech performance at the discourse level.
The effects of awareness-raising through stimulated recall on the repeated performance of the same task and on a new task of the same type
Authors: Sheppard Chris , Ellis Rod
Published: September 2018

The study explores the effects of intervening between the performance of the same task and whether these effects transfer to a new task. 40 Japanese university students completed the same monologic narrative task three times and then performed a new task of the same type (Time 4). 20 students just performed the tasks (the task-repetition group). The other 20 engaged in a stimulated recall procedure after the initial performance of the first task (the stimulated recall group). In both groups, structural complexity increased from Time 1 to Time 2 and was maintained, including in the new task. In contrast, accuracy remained the same for both groups when the same task was repeated and decreased notably in the new task. Fluency improved in both groups when the same task was repeated but declined when the new task was performed. However, performance of the new task was still significantly better than at Time 1. No differences were evident in complexity and accuracy between the task-repetition and the stimulated recall groups over time. The stimulated recall group demonstrated greater fluency than the task-repetition group when repeating the same task but not the new task. The chapter concludes with comments on the potential of stimulated recall as a means for enhancing the effects of task repetition.
Perform, reflect, recycle
Authors: Lynch Tony
Published: September 2018

In this chapter I review my research into the benefits of various forms of internal repetition in speaking tasks created for English for Academic Purposes (EAP) and English for Specific Purposes (ESP) courses at the University of Edinburgh. A common objective of the tasks was that they should create a context for language learners to recycle their performance – adapting and modifying their previous output, rather than merely doing the same thing again. I discuss four different speaking tasks and analyze the specific forms of recycling that they involved. After summarizing the evidence that each promoted improved learners’ spoken output in later task cycles, I contrast the findings with those from my recent replication study. In that study, I used one of the speaking tasks in a different pedagogic context, and found virtually no change in learners’ performances. I will suggest how this difference in uptake might stem from the way in which participants translated task-as-workplan into task-in-process, as well as from other contextual factors. Drawing on this synthesis of two decades of research, I propose a model of task recycling that incorporates the use of reflection activities, feedback, and comparator recordings, through which teachers can help second language learners to recycle and enhance their spoken English output.
Mediating input-based tasks for beginner learners through task repetition
Authors: Shintani Natsuko
Published: September 2018

This chapter examines task repetition from a sociocultural perspective. I will report a study examining how the dynamics of teacher-student interaction change when the same task is repeated over time. I draw on sociocultural theory by viewing task repetition as one way of dynamically mediating learners’ participation in an input-based task. The task was a listen-and-do task consisting of a simple procedure – the teacher’s commands followed by students’ action – with no requirement that the learners speak in the L2 (English). The same task was repeated nine times over five weeks. The participants were a group of six children, aged six, who had no L2 knowledge or experience of formal language learning. The lessons were audio- and video-recorded. The transcribed interactions and the video-data were analysed in detail to explore how the teacher’s scaffolding changed over time and how the students shifted from other-regulation to self-regulation. The analysis showed that the teacher employed two different approaches: mediating the task commands in the early lessons to assist the students’ comprehension and then pushing learners towards self-regulation in later lessons by reducing the level of support. The teacher’s actions led to co-construction and enabled the students to move from other-regulation to self-regulation in both comprehending key items in the input and voluntarily producing them. Overall, the study shows how the nature of ‘activity’ changed as the task-as-workplan was repeated over time.
Understanding benefits of repetition from a complex dynamic systems perspective
Authors: Nitta Ryo , Baba Kyoko
Published: September 2018

This classroom-based study explored the benefits of repeating a writing task over one year from the perspective of complex dynamic systems. The study specifically investigated how students’ use of self-regulation related to changes in L2 writing. Data were collected from 26 students in an EFL classroom at a university over 30 weeks. Students were engaged in a 10-minute timed-writing task on a chosen topic with immediate self-reflection every week. Students’ L2 compositions were analysed using fluency, syntactic and lexical measures, and their self-reflections written in L1 were analysed in terms of self-regulatory processes. The analysis of two focal students revealed that the first student showed more elaborate engagement and employed self-regulatory cycles of goal-setting and self-evaluation, which improved his L2 writing over time, while the second student with more limited engagement employed less elaborate self-regulatory processes, which reflected little change in his writing. Based on these cases, we contend that repeated encounters with tasks over extended periods create a valuable pedagogic environment, and within this context students’ agentic attitudes towards the L2 writing task are likely to influence their learning in significant ways.
Task repetition or task iteration?
Authors: Larsen-Freeman Diane
Published: September 2018

This chapter recommends a different understanding of task “repetition” from the perspective of Complex Dynamic Systems Theory (CDST). It suggests that a better term than “repetition” is “iteration”. While substituting one term for another might seem to be purely an academic exercise, doing so actually has important implications for researchers and teachers. For one, it is an acknowledgement of the common observation that learners’ performance on tasks will never be the same from one iteration to the next. In addition, it maintains that useful language pedagogy should build learners’ capacity to make meaning beyond their exploiting conventional uses of language to which learners have already been exposed. Further to this point, iteration instead of repetition is consistent with the CDST position that learning is not limited to reproduction. Through iteration, learners receive practice in adapting their language resources to mutable temporal and spatial contexts, and they construct their own learning paths. Also, the chapter problematizes the notion of transfer of learning, conceiving of it as transformation rather than transfer, and it addresses issues of measurement and nonlinearity. Finally, calling it task iteration honors the agency and uniqueness of learners and the construal that they give to the task at hand. As such, it calls for researchers to adopt a more emic perspective.
Continuous and intermittent heat acclimation and decay in team sport athletes
Authors: Duvnjak‐Zaknich Daniel M. , Wallman Karen E. , Dawson Brian T. , Peeling Peter
Published: September 2018

The aim of this study was to compare the impact of continuous (CON) and intermittent (INT) heat acclimation protocols on repeat‐sprint performance, and to also assess the degree of performance decay following acclimation. Using a pair‐matched, between subjects design, 16 trained male team sport athletes were allocated to either INT (8 sessions over 15 days) or CON acclimation (8 sessions over 8 days) groups. Participants performed a heat tolerance test (HTT) involving 60‐min of repeat‐sprint cycling with a 10‐min half time break (in 35.3 ± 0.7°C, 60.1 ± 4.0%; RH) two days pre‐ (pre‐HTT) and post‐acclimation (post‐HTT1). Decay was investigated with two further HTT's completed over the next two weeks (post‐HTT2 and post‐HTT3). Results showed the post‐HTT1 performance variables [mean power (pre‐HTT; INT = 1002.07 ± 173.74, CON = 1057.10 ± 180.07 / post‐HTT1; INT = 1097.11 ± 186.85, CON = 1163.77 ± 184.65 W), mean power (W.kg−1), total work (kJ) and work (J.kg−1)] were greater than pre‐HHT (p < 0.001) after acclimation, with no differences between INT and CON. No differences in final core and mean skin temperatures or heart rate existed after INT or CON acclimation, however 30 min measures for thermal sensation, perceived thirst and ratings of perceived exertion (as well as the final measure) were lower in post‐HTT1 (p < 0.05) in CON. Performance and thermoregulatory responses in post‐HTT2 and 3 were similar to post‐HTT1 in both INT and CON. These results indicate that prolonged repeat‐sprint exercise in the heat is improved after acclimation involving short, high‐intensity cycling sessions using either CON or INT protocols, with performance well‐maintained over the subsequent 2 weeks, despite removal of the heat stimulus.
A Critical Review of Botulinum Toxin Type A in the Prophylactic Treatment of Chronic Migraine in Adults
Authors: Mimeh Hanieh , Fenech Magrin Anna Maria , Myers Simon , Ghanem Ali M
Published: September 2018

Background

Migraine is a severe, disabling condition, ranked by World Health Organization as the sixth highest cause of disability worldwide. It greatly affects patients’ quality of life, functionality, and physical and mental health. The financial burden of migraine on the UK economy is conservatively estimated at £3.42 billion per year.

Objectives

The authors sought to perform an evidence-based literature review of the safety and efficacy of botulinum toxin type A (onaBoNTA) in the prophylactic treatment of adult patients suffering with chronic migraine (CM) compared to placebo. After the best evidence is identified, it will be utilized to formulate a protocol for doctors managing CM in their aesthetic clinic.

Methods

A comprehensive search of the current literature on the topic was performed by H.M. using Pubmed MEDLINE electronic database on March 1, 2018. All articles up to and inclusive of this date were included. Articles were limited to human studies and those in the English language. In vitro and animal studies were excluded.

Results

A total of 260 articles were identified. Of these, the excellent-quality, high-strength (level 1A) trials were short-listed to answer the research question.

Conclusions

There is high-quality, level 1A evidence to support onaBoNTA treatment in adults with CM is well tolerated and considered safe. However, it is associated with increased risk of adverse events and still some uncertainty exists associated with the degree onaBoNTA improves outcome measures compared to placebo. These data have been used to formulate The London Aesthetic Migraine Protocol (LAMP) to provide safe, evidence-based guidance for appropriately trained and experienced aesthetic practitioners to manage CM in their aesthetic clinics.

Level of Evidence: 1
Effect of vocabulary mapping for conditions on phenotype cohorts
Authors: Hripcsak George , Levine Matthew E , Shang Ning , Ryan Patrick B
Published: September 2018

Objective

To study the effect on patient cohorts of mapping condition (diagnosis) codes from source billing vocabularies to a clinical vocabulary.

Materials and Methods

Nine International Classification of Diseases, Ninth Revision, Clinical Modification (ICD9-CM) concept sets were extracted from eMERGE network phenotypes, translated to Systematized Nomenclature of Medicine - Clinical Terms concept sets, and applied to patient data that were mapped from source ICD9-CM and ICD10-CM codes to Systematized Nomenclature of Medicine - Clinical Terms codes using Observational Health Data Sciences and Informatics (OHDSI) Observational Medical Outcomes Partnership (OMOP) vocabulary mappings. The original ICD9-CM concept set and a concept set extended to ICD10-CM were used to create patient cohorts that served as gold standards.

Results

Four phenotype concept sets were able to be translated to Systematized Nomenclature of Medicine - Clinical Terms without ambiguities and were able to perform perfectly with respect to the gold standards. The other 5 lost performance when 2 or more ICD9-CM or ICD10-CM codes mapped to the same Systematized Nomenclature of Medicine - Clinical Terms code. The patient cohorts had a total error (false positive and false negative) of up to 0.15% compared to querying ICD9-CM source data and up to 0.26% compared to querying ICD9-CM and ICD10-CM data. Knowledge engineering was required to produce that performance; simple automated methods to generate concept sets had errors up to 10% (one outlier at 250%).

Discussion

The translation of data from source vocabularies to Systematized Nomenclature of Medicine - Clinical Terms (SNOMED CT) resulted in very small error rates that were an order of magnitude smaller than other error sources.

Conclusion

It appears possible to map diagnoses from disparate vocabularies to a single clinical vocabulary and carry out research using a single set of definitions, thus improving efficiency and transportability of research.
On the way from misery to happiness? A longitudinal perspective on economic migration and well-being
Authors: Kratz Fabian
Published: September 2018

The assessment of returns from migration lies at the very heart of migration research. While a growing body of literature examines the links between migration and well-being, dynamic relationships require further elaboration. Using the longest running, nationally representative panel study with information on well-being, the German Socio-Economic Panel (1985–2016) this article addresses two essential, as yet unresolved, questions: How does the favourable self-selection of economic migrants affect their well-being before relocation?How does the well-being of economic migrants develop when individuals approach migration, and thereafter?

Results show that—although favourably selected regarding determinants of well-being—economically motivated migrants are not happier before relocating than those who stay. Furthermore, economic migration has a causal impact on well-being, net of both observed and unobserved differences between migrants and stayers. This impact is transitory for women and long-lasting for men. For men, the results corroborate the view that migration enables access to opportunity structures favouring the pursuit of individual happiness. Results also differ by migration type: While long-distance movers and return migrants show a period of depressed happiness before a move, these findings do not hold for short-distance and onward migrants. Furthermore, moving towards urban areas results in stronger permanent effects than moving towards rural areas.
Characterization of the Response of Ornamental Graminoids to Attempted Infection by Sclerotinia sclerotiorum
Authors: Grabowski Michelle A. , Malvick Dean K.
Published: September 2018

Sclerotinia sclerotiorum causes Sclerotinia stem rot (SSR) (also called white mold), resulting in stem rot and death of many common herbaceous ornamental plant species. Resistant plants would be useful to manage SSR; however, the host range of S. sclerotiorum is unclear. The goal of this study was to determine how the ornamental graminoids Pennisetum glaucum, Setaria italica, Juncus inflexus, Carex flagellifera, Isolepis cernua, and Acorus gramineus respond to inoculation with S. sclerotiorum. Plants were inoculated in the field and in controlled environments at 13, 16, 19, or 22°C with or without wounding, and evaluated for SSR. Inoculated detached leaves were stained to examine infection and oxalate oxidase production. A. gramineus developed SSR in field and controlled environments. Sclerotinia stem rot was not observed on P. glaucum in field environments. The disease developed on P. glaucum and S. italica in controlled environments, and severity increased with decreasing temperature and wounding. J. inflexus, C. flagellifera, and I. cernua developed no or minor symptoms of SSR in field and controlled environments. Mycelia penetrated A. gramineus leaves 24 h after inoculation (HAI) and P. glaucum at 48 HAI, but did not penetrate J. inflexus at 24, 48, or 96 HAI. Oxalate oxidase was not detected in inoculated leaves of these ornamental graminoids. The results illuminate S. sclerotiorum’s interactions with monocots and broaden the understanding of SSR resistance in ornamental grasses.