The Impact of Recasts on Second Language Acquisition

The roles of recasts have been intensively studied in the first language (L1) research. This essay explores the role of recasts in second language acquisition, mainly focusing on discussing the studies addressing the following two issues: (1) the effects of recasts on the interaction of communication oriented classroom; (2) the role of recasts in promoting interlanguage development.Mixed evidence has been presented by second language (L2) studies regarding the impacts of recasts on second language acquisition.

A Brief Review on Recasts

Recast is the most frequently used error correction technique adopted by teachers in the communicative oriented classrooms. This article illustrates the reasons for its popularity, also discusses how to use recast effectively in practice.

A Study on Negative Feedback in English Extensive Reading Course

Negative feedback serves as a means of correcting and rectifying students’utterances.While content feedback is commonly used in extensive reading course,indirect feedback dominates in written assignments,providing students with opportunities for second thoughts and self-correction.For oral limited-response and open-ended questions,recasts are predominantly used to give students more time to reflect and reduce teacher talk,thereby mitigating anxiety and enhancing learning motivation.

Second Language Research on Recasts:A Critical Review in Response to an Ongoing Debate

This paper reviews important second language research on recasts in response to a recent debate between Goo and Mackey （2013） and Lyster and Ranta （2013） in the journal Studies in Second Language Acquisition. It begins by clarifying the definition of recasts and then examines several controversial issues featuring prominently in the debate, including the theoretical underpinnings of existing research on recasts, mixed findings about their effectiveness in language acquisition, and methodological concerns in effectiveness research. The primary aim of this paper is to demarcate common ground and disagreement that are emerging in this debate and, based on a synthesis and critique of previous empirical studies, to identify directions for future research. It also explores pedagogical implications of recasts research for English-as-a-foreign-language contexts.

The Effects of Recasts and Working Memory on the Development of Implicit and Explicit Knowledge

This paper aims to investigate the effects of recasts and working memory on the acquisition of Korean morphological causatives by advanced Chinese learners of Korean. Participants were randomly assigned to two groups： A experimental group and a control group. The experimental group received intensive recasts during task-based interaction, whereas the control group did not. The effects of recasts were measured by two types of tests： An elicited imitation test, as a measure of implicit knowledge, and an untimed grammaticality judgment test, as a measure of explicit knowledge. The findings are as follows. First, from the pretest to the delayed posttest, recasts facilitated the learners＇ acquisition of causative construction by developing both their implicit and explicit knowledge. Second, the results of delayed posttests showed that recasts were more effective in aiding the development of implicit knowledge than explicit knowledge. Third, working memory was found to be a significant covariate in the facilitative effects of recasts on explicit knowledge; that is, it mediated the development of explicit knowledge via recasts as a significant individual difference factor. The effects of recasts were maintained even when the impact of working memory was controlled. （189 words）

RECASTS AS CORRECTIVE FEEDBACK IN CHINA’S ENGLISH CLASSROOM INTERACTION

本文基于30节课堂教学语料调查了中国英语教师使用部分重说反馈语(recast)的频率和规律。数据表明,中国英语教师并不倾向在课堂中频繁使用部分重说;而当他们使用时,他们一般针对学生的语法错误使用部分重说;并且和其它反馈语相比,部分重说不能导致学生产出更多的即时修正。原因可能与部分重说的性质和教师使用它的技巧有关。

Is Recast the Most Effective Type of Corrective Feedback？ --Under Cognitive and Sociolinguistic Approach

Currently, there are a variety of researches on corrective feedback, especially on recasts. Most of researches are experiment-based and depend on the certain context. This paper addresses the question of ＂Is recast the most effective form of corrective feedback？＂ by two of Second Language Acquisition （SLA） approaches： cognitive approach and sociolinguistic approach. Empirical research will be used as complement. Theoretically speaking, SLA hypotheses in cognitive approach exist disagreements. Interaction hypothesis favors recast while both input hypothesis and output hypothesis doubt the effectiveness of it. Sociolinguistic approach underscores the significance of appropriate and timely corrective feedback and does not give more credit to certain strategy. Both approaches provide the pedagogical implications and elements to take into account for adopting recasts.

A Comparison in Laser Precision Drilling of Stainless Steel 304 with Nanosecond and Picosecond Laser Pulses

Precision drilling with picosecond laser has been advocated to significantly improve the quality of micro-holes with reduced recast layer thickness and almost no heat affected zone.However,a detailed comparison between nanosecond and picosecond laser drilling techniques has rarely been reported in previous research.In the present study,a series of micro-holes are manufactured on stainless steel 304 using a nanosecond and a picosecond laser drilling system,respectively.The quality of the micro-holes,e.g.,recast layer,micro-crack,circularity,and conicity,etc,is evaluated by employing an optical microscope,an optical interferometer,and a scanning electron microscope.Additionally,the micro-structure of the samples between the edges of the micro-holes and the parent material is compared following etching treatment.The researching results show that a great amount of spattering material accumulated at the entrance ends of the nanosecond laser drilled micro-holes.The formation of a recast layer with a thickness of;5μm is detected on the side walls,associated with initiation of micro-cracks.Tapering phenomenon is also observed and the circularity of the micro-holes is rather poor.With regard to the micro-holes drilled by picosecond laser,the entrance ends,the exit ends,and the side walls are quite smooth without accumulation of spattering material,formation of recast layer and micro-cracks.The circularity of the micro-holes is fairly good without observation of tapering phenomenon.Furthermore,there is no obvious difference as for the micro-structure between the edges of the micro-holes and the parent material.This study proposes a picosecond laser helical drilling technique which can be used for effective manufacturing of high quality micro-holes.

Theoretical and Experimental Investigation of Laser Milling Assisted with Jet Electrochemical Machining

In laser milling assisted with jet electrochemical machining(LMAJECM),the source of energy is a pulsed laser beam aligned coaxially with a jet of electrolyte,which focuses optical energy on the surface of workpiece.The impact of jet of electrolyte develops a state-of-art work to perform operations such as electrolytic etching,effective cooling,and transportation of debris.Therefore,a special jet cell is designed to obtain stable jet as to be a kind of noncontact tool,i.e.,electrode.According to the theoretical model of on-off pulse time process,laser machining and electrolytic anodization are simulated by finite element analysis(FEA)method.Grooves on a 0.5mm thick 321 stainless steel sheet produced by LMAJECM is performed with pulsed Nd:YAG laser at the second harmonic wavelength.Compared with laser milling under ambient atmosphere conditions,the recast layer and burrs are effectively diminished.And the accuracy of depth is dedicated to laser milling,whilst that of width is dominated by jet electrochemical machining.It is demonstrated that LMAJECM can be a highly potential approach for fabricating 3-D micro components.

Academic health sciences libraries as connectors to knowledge beyond literature

Libraries at large academic medical centers in the United States are undergoing a transformation from their traditional role as knowledge repositories to a new role as connectors to knowledge. This transformation is fueled by the move away from library-held print resources as the primary source of information used by researchers,clinicians and students. Knowledge resources critical to the missions of academic medical centers now include online books and journals,very large data sets,software tools,and expertise far beyond the walls of the library. This article illustrates how Bernard Becker Medical Library at Washington University in St. Louis has seized the opportunity to recast itself as a connector to knowledge beyond literature and strengthen its vital role within the university as a catalyst for learning and discovery.

How Selection of a Target Feature Impacts Corrective Feedback:Finding Answers Through Meta-Analysis of Chinese EFL Learners

Rather than looking at variables like grammatical feature type,proficiency,and L1 as separate,we must start to view them as interrelated and codependent.In this way,educators may finally learn how to maximize the effect of corrective feedback(CF).A meta-analysis of 13 studies was conducted to examine four styles of CF(implicit prompt,implicit reformulation,explicit prompt,and explicit reformulation)along with the following variables:grammatical feature type,L1 similarity(with Mandarin Chinese),and proficiency level.Results suggest that effect size is highly dependent upon the grammatical feature targeted.Explicit feedback appears to have a scaffolding effect for more semantically or syntactically complex grammatical features.Implicit reformulations(recasts)also provide scaffolding,yielding larger effect sizes than implicit prompts when used with L1 dissimilar features that are more semantically or syntactically complex.

SYNTHESIS, CHARACTERIZATION AND APPLICATION IN PEMFC OF ZIRCONIUM OXO PHOSPHATE-SULFATE

Mesoporous zirconium oxo phosphate-sulfate was synthesized by hydrothermal method with hexadecyltrithylammonium bromide(CTAB)as the template and with zirconium nitrate or zirconium oxychloride as zirconium source.The optimum two-stage process was established, ^(31)P MAS NMR showed that the states of phosphate species were changed with further postsynthesis treatment by sulfate acid. The transformations of the structures at different temperatures from room temperature to 1173 K were investigated by XRD. ...

Effect of Surface Treatment on Elemental Composition of Recast NiCr Alloy

Objective: The aim of this study was to compare the effects of different surface treatments on the elemental composition stability of as-received and recast types of NiCr casting alloys. Material and Methods: Six commercial NiCr dental casting alloys (Kera N, Nodelco, Bellabond, Wiron 99, Metaplus VK, and Tritech D) were used in this study. Seventy-two specimens (12 × 12 × 1.2 mm) were produced using the lost-wax casting process. Three casting protocols were established in relation to the proportion of as-received and recast alloys: Group A (100% as-received metal), Group B (50 wt% new metal, 50 wt% once-recast metal), and Group C (100% once-recast metal). Two specimens in every group received two different surface treatments: sandblasting with 110 μmm Al2O3 or oxidation firing. An elemental analysis was performed with x-ray energy-dispersive spectroscopy. Results were subjected to one-way analysis of variance and Tukey HSD tests. Results: The elemental composition was significantly different in the casting groups and treatment groups (p < 0.05). The lowest mean weight percentage Ni value was recorded for Group C and the highest for Group A. Aluminum-oxide sandblasting of the alloy surface reduced the mean weight percentage for Cr. Conclusion: Recasting metal alloys may adversely affect surface quality.

Improving surface integrity of micro-holes in ECDM using ultrahigh-speed rotary of tool cathode and non-water-based electrolyte

The surface integrity of metal micro-hole structures produced by electrochemical discharge machining is unsatisfactory owing to the insufficient reaction area and strength of electrolysis action.A novel ultrahigh-speed Rotary Electrochemical Discharge Machining(R-ECDM)using non-water-based electrolyte is proposed to improve surface integrity by changing the breakdown medium of spark discharge and increasing the reaction area and strength of electrolysis.A mathematical model was developed to establish the relationship between rotational speed and forces acting on the bubble.Based on the magnitude of forces,controlling rotational speed changed the behavior and departure radius of bubbles on the cathode surface.High-speed photographs validate that,in the mathematical model,the number and departure radius of bubbles on the cathode surface gradually decrease with the increase of rotational speed.The experimental results show that the roughness(Ra)of the micro-hole sidewall decreases from 2.54μm to 0.20μm when the rotational speed increases from 500 r/min to 40000 r/min.The length loss and wear ratio of the cathode are only 9.75μm and 6.5%,respectively.Finally,the micro-holes array with recast-free and surface roughness of 0.20μm is fabricated,demonstrating that the proposed approach contributes to improving surface integrity of metal micro-holes.

Breakthrough detection in electrochemical discharge drilling to enhance machining stability

Film cooling holes are widely used in aero-engine turbine blades.These blades feature large numbers of holes with complex angles and require a high level of surface integrity.Electrochemical discharge drilling(ECDD)combines the high efficiency of electrical discharge drilling(EDD)with high quality of electrochemical drilling(ECD).However,due to the existence of a variety of energy for material removal,accurate and timely detection of breakthroughs is fraught with difficulties.An insufficient preset setting distance results in a tiny exit aperture,influencing the structure's shape.In addition,the electrode is prone to bending at a large overfeeding distance,causing secondary discharge damaging sidewall surface integrity.This paper compares and analyzes the characteristics of processing waveforms using EDD and ECDD.A novel breakthrough detection method is proposed based on the variance signal of average voltage(VSAV)to increase machining stability and achieve fabrication without a recast layer.This method extracts the fluctuation transformation by calculating the variance of the average.Following signal detection,the overfeeding distance is quantified.An experiment is used to validate the breakthrough detection with 100%accuracy in all tests.The optimum overfeeding distances for hole angles of 0°,30°,and 60° are obtained,and the stable removal of the recast layer is realized.Finally,the effectiveness of the method is verified on a typical workpiece with a double-wall structure and a nickel-based single crystal blade.

Explicit Recast, Implicit Recast and the Acquisition of English Noun Plural: A Comparative Study

该研究对比分析了显性重述和隐性重述对中国英语学习者英语名词复数习得的影响。63名小学六年级学生被随机分配到显性重述组、隐性重述组和控制组。每组21人。本研究的目标语法结构为英语名词复数。受试者单独同研究者完成了实验干预—信息差型任务。针对受试者产生的错误目标结构,显性重述组得到显性重述作为反馈,隐性重述组得到隐性重述作为反馈。而控制组得不到任何纠错型反馈。受试者关于目标结构的知识分别进行了前测、后测、延时后测。配对样本t检验和单因素方差分析的结果表明:三组的后测成绩都比前测成绩有显著性的提高;显性重述组的两次后测成绩都比隐性重述和控制组好;隐性重述组同控制组之间没有显著性差异。本文根据注意假设、自发诱导理论和平衡假设讨论了实验结果。在理论上,显性重述相对于隐性重述的优势证实了负面信息在二语习得中的有益作用。在教学上,其说明显性重述比隐性重述更适用于二语课堂。

Modeling and Experimental Investigation of Laser Drilling with Jet Electrochemical Machining

As two kinds of defects, recast layers and spatters, commonly accompanied by laser-drilled holes always prevent the laser drilling technique from extending its applications in aerospace and aircraft industries, therefore, a novel hybrid process incorpo- rating laser drilling with jet electrochemical machining （JECM-LD） has been developed to solve these problems as well as improve the overall quality of laser-drilled holes. It is executed by directing an electrolyte jet coaxially aligned with a laser beam onto the workpiece surface. During the process, the electrolyte jet produces electrochemical reaction with the surface material, effective cooling of it and carries away the process scraps. A two-dimensional mathematical model is proposed to describe the shape of the holes machined by JECM-LD. The model is verified through comparison between the results from simulation and those from experiments conducted on the test pieces made of 321 stainless steel 0.5 mm thick processed by the pulsed Nd：YAG laser at second harmonic wavelength. An examination of the experimental results under an optical microscope discovers that, by contrast with the laser drilling in air, the JECM-LD has effectively removed the recast layers and spatters, but its efficiency dropped by about 30%.

Multi-channel discharge characteristics cutting by ultra-fine wire-EDM

Compared with a copper wire electrode, molybdenum wire with a poor conductor is usually used as the electrode in high speed wire-cut electrical discharge machining(HSWEDM), so the resistance of an ultra-fine wire cannot be ignored. To study the differences of discharge characteristics between the ultra-fine wire and the conventional diameter wire, the continuous discharge waveform of two kinds of wire electrodes was compared. It was found that there was a multichannel discharge phenomenon in the discharge waveform cutting by ultra-fine wire. Through the establishment of a discharge equivalent circuit model and the simulation analysis of the electrostatic field, it was found that the reason why ultra-fine wire is easy to form multi-channel discharge phenomenon is that the potential difference between the wire and the workpiece increased linearly along the axis of the wire. Besides, etching products like metal particles will distort the electric field between the electrodes. Both of them make it easy to form a multi-channel discharge in machining.The results show that the distributions of the equivalent resistance and the peak current are affected by the multi-channel discharge position. Multi-channel discharge can disperse energy and increase effective discharge frequency. Compared with the 0 mm spacing, at a spacing of 100 mm, the machining efficiency increases by 8.7%, the surface roughness decreases by 37.7%, and the average recast layer thickness decreases by 46.6% under the condition of ultra-fine wire-EDM.

Effect of no-load rate on recast layer cutting by ultra fine wire-EDM

Via material erosion in wire electrical discharge machining(WEDM),recast layers form on the surfaces of workpiece.In addition,ultra fine Wire-EDM can be usually cut once.To reduce the thickness of the recast layer as much as possible,the wire electrical discharge-electrochemical machining(WEDCM)method was proposed,which is based on the micro conductivity of the dielectric and microelectrolytic characteristics by adjusting the no-load rate of the pulse in the machining process.Furthermore,a state discrimination and servo control system based on discharge current was designed.The experiment results of different no-load rates show that the electrolytic effects increase as the no-load rate increases,and the main machining process is spark discharge erosion with a no-load rate in the range of 10%to 80%.At 90%no-load rate,the amount of recast layer formation in the forward direction of the wire electrode is almost the same as that of electrolytic dissolution,and it can be practically processed without a recast layer.Compared with10%no-load rate,the kerf width only increases by 7.5%.

Recasting Anti-commercial Bribery Provisions in Criminal Law

Commercial bribery makes up a high proportion of all corruption involving public functionaries in China. As such, it must be a present and future focus of the fight against corruption. In order to better achieve the objective of restraining public power, we should adjust the criteria for what constitutes the crime of corruption and the content of the specific assessment of this crime in Chinese criminal law in the light of the characteristics and new manifestations of commercial bribery, with a view to combating it more effectively.View full textDownload full text