Effects of Cooperative Learning on the Oral Proficiency of Chinese Students in the Tertiary-level EFL Classroom

To explore the impact of cooperative learning (CL) on Chinese students’ English oral proficiency, a 15-week quasi-experiment was conducted in a Chinese university during the first term of the Academic Year 2007-2008. A non-randomized pre-test-post-test control group research design was adopted with 37 first-year students in the experimental class (the EC) and 36 in the control class (the CC). The EC students participated in CL in conjunction with regular language instruction in an integrated skills course. They were exposed to CL activities for about 30 minutes in each session, making up a total of 90 minutes every other week. The CC students only received conventional whole-class instruction. The oral pre-test and post-test were conducted before and after the intervention to measure the students’ gains in oral proficiency. The National College Entrance English Exam (NCEEE) and a final term English exam (FTEE) were employed to measure their improvement in general proficiency. Interactional data of two EC groups (the ESs) and two CC groups (the CSs) were collected by the oral pre-test and post-test, and a pre-task and post-task in the classroom. The purpose was to detect any change in their interactional strategy use. The interactional data of the ESs and the CSs were transcribed, and interactional strategies were identified in the transcriptions. The quantitative results are presented using descriptive analysis as well as inferential analysis. Effect size was also measured to examine the relative magnitude of the treatment. The interactional strategies used by these two groups were compared. The quantitative results revealed a null experimental effect on overall oral proficiency and on its components: grammar and vocabulary, pronunciation and discourse management, but the effect on interactive communication was inconclusive. Conversation analysis showed that the ESs appeared to do somewhat better in interactional strategy use than the CSs. Also, the results did not significantly favour CL in comparison with conventional whole-class instruction in helping Chinese students improve their general proficiency. As this study was conducted with intact classes with a small sample, the results may only be generalized to similar universities in China, and may not be generalized to all the foreign language learners or institutions in China

Effects of cooperative learning on the oral proficiency of Chinese students in the tertiary-level EFL classroom

To explore the impact of cooperative learning (CL) on Chinese students’ English oral proficiency, a 15-week quasi-experiment was conducted in a Chinese university during the first term of the Academic Year 2007-2008. A non-randomized pre-test-post-test control group research design was adopted with 37 first-year students in the experimental class (the EC) and 36 in the control class (the CC). The EC students participated in CL in conjunction with regular language instruction in an integrated skills course. They were exposed to CL activities for about 30 minutes in each session, making up a total of 90 minutes every other week. The CC students only received conventional whole-class instruction. The oral pre-test and post-test were conducted before and after the intervention to measure the students’ gains in oral proficiency. The National College Entrance English Exam (NCEEE) and a final term English exam (FTEE) were employed to measure their improvement in general proficiency. Interactional data of two EC groups (the ESs) and two CC groups (the CSs) were collected by the oral pre-test and post-test, and a pre-task and post-task in the classroom. The purpose was to detect any change in their interactional strategy use. The interactional data of the ESs and the CSs were transcribed, and interactional strategies were identified in the transcriptions. The quantitative results are presented using descriptive analysis as well as inferential analysis. Effect size was also measured to examine the relative magnitude of the treatment. The interactional strategies used by these two groups were compared. The quantitative results revealed a null experimental effect on overall oral proficiency and on its components: grammar and vocabulary, pronunciation and discourse management, but the effect on interactive communication was inconclusive. Conversation analysis showed that the ESs appeared to do somewhat better in interactional strategy use than the CSs. Also, the results did not significantly favour CL in comparison with conventional whole-class instruction in helping Chinese students improve their general proficiency. As this study was conducted with intact classes with a small sample, the results may only be generalized to similar universities in China, and may not be generalized to all the foreign language learners or institutions in China.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Repeatability and reproducibility of eight macular intra-retinal layer thicknesses determined by an automated segmentation algorithm using two SD-OCT instruments.

PURPOSE: To evaluate the repeatability, reproducibility, and agreement of thickness profile measurements of eight intra-retinal layers determined by an automated algorithm applied to optical coherence tomography (OCT) images from two different instruments. METHODS: Twenty normal subjects (12 males, 8 females; 24 to 32 years old) were enrolled. Imaging was performed with a custom built ultra-high resolution OCT instrument (UHR-OCT, ∼3 µm resolution) and a commercial RTVue100 OCT (∼5 µm resolution) instrument. An automated algorithm was developed to segment the macular retina into eight layers and quantitate the thickness of each layer. The right eye of each subject was imaged two times by the first examiner using each instrument to assess intra-observer repeatability and once by the second examiner to assess inter-observer reproducibility. The intraclass correlation coefficient (ICC) and coefficients of repeatability and reproducibility (COR) were analyzed to evaluate the reliability. RESULTS: The ICCs for the intra-observer repeatability and inter-observer reproducibility of both SD-OCT instruments were greater than 0.945 for the total retina and all intra-retinal layers, except the photoreceptor inner segments, which ranged from 0.051 to 0.643, and the outer segments, which ranged from 0.709 to 0.959. The CORs were less than 6.73% for the total retina and all intra-retinal layers. The total retinal thickness measured by the UHR-OCT was significantly thinner than that measured by the RTVue100. However, the ICC for agreement of the thickness profiles between UHR-OCT and RTVue OCT were greater than 0.80 except for the inner segment and outer segment layers. CONCLUSIONS: Thickness measurements of the intra-retinal layers determined by the automated algorithm are reliable when applied to images acquired by the UHR-OCT and RTVue100 instruments

Diurnal Variation of Upper and Lower Tear Menisci

To determine diurnal variation of tear menisci around upper and lower eyelids in normal subjects. Prospective laboratory investigation. Twenty young healthy Chinese subjects (10 women and 10 men; mean age, 21.3 years; range, 20 to 26 years) with no history of contact lens wear or previously diagnosed dry eye were recruited. A custom-built, real-time anterior segment optical coherence tomography (OCT) instrument was used simultaneously to image the upper and lower tear menisci. Repeated measurements immediately after blinking were conducted on both eyes during a 24-hour period, including immediately before and after sleeping. Dimensional information of the tear menisci were obtained from the OCT images using custom software. There were no significant differences between right and left menisci, nor were there any differences between females and males in the lower tear meniscus ( P > .05, repeated-measurement analysis of variance [ANOVA]). Although the lower tear meniscus variables were correlated strongly with upper meniscus variables, the lower meniscus was significantly greater than the upper one. Significant diurnal variations ( P < .05, repeated-measurement ANOVA) of all measured variables were observed during the study period. Tear menisci were significantly increased at eye opening after overnight sleep compared with the baseline before sleep at 10 pm ( P < .001, post hoc tests). They remained elevated up to 10 minutes after eye opening ( P < .001, post hoc tests). Real-time OCT can provide useful information regarding the dynamics of the tear system. Diurnal variation of the upper and lower tear menisci occur

Biometry of anterior segment of human eye on both horizontal and vertical meridians during accommodation imaged with extended scan depth optical coherence tomography.

To determine the biometry of anterior segment dimensions of the human eye on both horizontal and vertical meridians with extended scan depth optical coherence tomography (OCT) during accommodation.Twenty pre-presbyopic volunteers, aged between 24 and 30, were recruited. The ocular anterior segment of each subject was imaged using an extended scan depth OCT under non- and 3.0 diopters (D) of accommodative demands on both horizontal and vertical meridians. All the images were analyzed to yield the following parameters: pupil diameter (PD), anterior chamber depth (ACD), anterior and posterior surface curvatures of the crystalline lens (ASC and PSC) and the lens thickness (LT). Two consecutive measurements were performed to assess the repeatability and reproducibility of this OCT. They were evaluated by calculating the within-subject standard deviation (SD), a paired t-test, intra-class correlation coefficients (ICC) and the coefficient of repeatability/reproducibility (CoR).There were no significant differences between two consecutive measurements on either horizontal or vertical meridians under both two different accommodative statuses (P>0.05). The ICC for all parameters ranged from 0.775 to 0.998, except for the PSC (0.550) on the horizontal meridian under the non-accommodative status. In addition, the CoR for most of the parameters were excellent (0.004% to 4.89%). In all the parameters, only PD and PSC were found different between the horizontal and vertical meridians under both accommodative statuses (P<0.05). PD, ACD, ASC and PSC under accommodative status were significantly smaller than those under the non-accommodative status, except that the PSC at the vertical meridian did not change. In addition, LT was significantly increased when accommodation.The extended scan depth OCT successfully measured the dimensions of the anterior eye during accommodation with good repeatability and reproducibility on both horizontal and vertical meridians. The asymmetry of lens posterior surface and oval-shaped pupil were found during accommodation

Relationships among retinal/choroidal thickness, retinal microvascular network and visual field in high myopia

Purpose To determine the relationships among retinal/choroidal thickness, retinal microvascular network and visual field in high myopia. Methods This cross‐sectional study included a total of 62 subjects, comprising 31 eyes with high myopia and 31 eyes with emmetropia or low myopia. Optical coherence tomography was used to quantify the thickness of ganglion cell complex (GCC), inner nuclear layer and outer plexiform layer (INOPL), outer retinal layer (ORL) and choroid layer (ChL). Optical coherence tomography angiography was used to quantify the superficial vessel density (SVD) and deep vessel density (DVD). Retinal light sensitivity (RLS) was measured by microperimetry‐1 (MP1). The inner ring (1–1.75 mm), the outer ring (1.75–2.5 mm) and the whole ring (1–2.5 mm) around the macula were analysed and compared between the two groups. Pearson correlation analysis was performed to analyse the relationship among them. Results In the highly myopic group, the thinning of retinal/choroidal thickness and the decrease in retinal vessel density and RLS were found when compared to the emmetropia or low myopia (p  0.05), but DVD showed a negative correlation with ORL (r = −0.474, p = 0.007). Conclusion Early visual field defects in highly myopic eyes may be influenced by the ORL loss and defect of choroidal circulation. The deep retinal microvascular network may have a compensatory action in the hypoxic setting of high myopia

Fully automated biometry of in situ intraocular lenses using long scan depth spectral-domain optical coherence tomography

Spectral-domain optical coherence tomography (SD-OCT) was used to automatically measure accommodative biometric changes in the anterior segment of eyes implanted with an intraocular lens (IOL). The repeatability and reliability of the automated measurements were also evaluated. Long scan depth SD-OCT was used to image the anterior segment of eyes implanted with IOLs. A fully automated algorithm was used to detect the boundaries of the cornea and IOL and yielded the measurements. The results included anterior segment dimensions in IOL eyes and the deflection of the IOLs. Automated measurements were validated in vitro and compared with the manual results in vivo on 15 cross-sectional images from patients with IOLs. Five eyes with five different types of IOLs, respectively, were enrolled to test the repeatability of the automated measurements during accommodation. Intraocular lens central thickness and anterior and posterior curvature radii measured by long scan depth SD-OCT in vitro and in a model eye matched well with those determined by a micrometer caliper and interferometer. In vivo, there was good correlation of the biometric data determined by automated and manual segmentations (P0.05). Anterior chamber depth and pupil diameter showed significant changes between the nonaccommodative and 2.5-D accommodative states (P0.05). The long scan depth SD-OCT with the automated algorithm was verified to have a great potential in studying accommodative biometric changes of the anterior segment in eyes with IOLs and IOL deflections

Agreement of corneal epithelial profiles produced by automated segmentation of SD-OCT images having different optical resolutions

Using a custom-developed segmentation algorithm, agreement of corneal epithelial thickness profile measurements between two spectral domain optical coherence tomography (SD-OCT) systems was assessed. Eighteen left eyes (18 subjects; mean±standard deviation; age, 23.2±0.9 years) were imaged twice on nonconsecutive days by a custom-built ultra-high resolution OCT (UHR-OCT) system and a commercial RTVue OCT system. A segmentation algorithm based on axial gradient information and a shortest path search was developed to measure corneal epithelial thickness profiles from the SD-OCT images. There was good correlation between the automated and manual segmentation positions of the epithelium. The epithelial thickness differences between automated and manual segmentations by the UHR-OCT and RTVue OCT systems were 0.4±0.3 μm and 1.1±0.5 μm, respectively. The intraclass correlation coefficients (ICCs) and coefficients of repeatability for repeated UHR-OCT measurements of epithelial thickness were 0.90±0.05 μm and 1.44±0.01 μm, respectively. For RTVue OCT, the ICCs and coefficients of repeatability were 0.88±0.04 μm and 2.16±0.01 μm, respectively. The epithelial thickness measured by RTVue OCT was 1.1±0.2 μm greater than that by UHR-OCT (P<0.05, paired t test), and ICC for the agreement between the 2 systems was 0.85±0.06. The average 95% limit of agreement was -1.67 to 3.79 μm. For images of different qualities from both SD-OCT systems, the custom-developed automated segmentation of the corneal epithelium had good repeatability for thickness profile measurements. The accurate and precise algorithm also demonstrated good agreement of epithelial thickness profile measurements between the two SD-OCT systems

Anterior Segment Biometry of the Accommodating Intraocular Lens and its Relationship With the Amplitude of Accommodation

To evaluate the anterior segment biometry of the Tetraflex accommodating intraocular lens (AIOL) and the contribution of forward movement to the amplitude of accommodation (AMP). Patients who underwent phacoemulsification with implantation of Tetraflex AIOLs and control nonaccommodating intraocular lenses were imaged by custom-built, long scan depth spectral-domain optical coherence tomography at relaxed and maximal accommodative states. Anterior segment biometry was performed and correlated with the clinical manifestation including AMP. Patients in the Tetraflex group showed better distance-corrected near visual acuity (logMAR 0.43±0.10 vs. logMAR 0.51±0.10, P<0.05) and greater AMP (1.99±0.58 diopters [D] vs. 1.59±0.45 D, P<0.05) compared with the control group. The measurement of the postoperative anterior chamber depth (ACD) during accommodation showed a forward movement of the AIOLs in 16 eyes (69.6%). Compared with the control group, a greater proportion of cases in the Tetraflex group experienced forward movement (χ test, P<0.001). The AMP in the AIOL group negatively correlated with changes in postoperative ACD during accommodation (r=-0.47, P<0.05), whereas AMP in the control group negatively correlated with postoperative pupil diameter (r=-0.57, P<0.05). The Tetraflex AIOLs seemed to have a tendency for forward movement; however, the slight forward axial shifts of the Tetraflex AIOL during natural accommodation may not produce a clinically relevant change in optical power