272 research outputs found
Two Perspectives on Writing: A Cross-Context Study of Second Language Writing
The focus of writing pedagogy for L2 undergraduate writers in ESL contexts has been primarily on addressing writing demands across the curriculum (Johns, 2009; Silva, 1990). The literature from EFL settings, however, depicts a very complex picture that makes it difficult to generalize purposes and needs across the settings (Cimasko & Reichelt, 2011). Despite the indication that L2 writing is differently conceptualized across many settings, few studies have been conducted to examine contextual variation. Documenting local conceptions and contextual factors in different settings could not only inform teachers of the importance of accounting for local exigencies in teaching, but also provide new insights on pedagogical scholarship of L2 writing that has primarily accounted for ESL contexts.
To shed light on the situated nature of L2 writing, the present cross-context case study examined practices of teaching and learning L2 writing in two settings, i.e., an English Language Program (ELP) at āSouthernā University in the U.S. and an ELP at āHahnā University in Korea. By using multiple data collection methods ā class observation, interviews, and document analysis, the study compared teachersā pedagogical conceptualization and learnersā perceptions of L2 writing need. Findings show that the Southern-ELP predominantly conceptualized L2 writing as preparation for academic literacy demands in coursework whereas the Hahn-ELP viewed L2 writing as an end in itself by teaching mainly prescribed patterns. These differences originated from their understanding of local linguistic ecology and teacher training backgrounds. Studentsā perceived needs for L2 writing, despite internal variation in both settings, showed divergence across the contexts. While many Southern students reported goals for learning-to-write in L2, most Hahn freshmen did not express similar goals. These Hahn students indicated needs to develop their linguistic proficiency through writing. These disparate views emanated from differences in L2 writing demands in coursework and linguistic proficiency.
The findings suggest that pedagogical scholarship of L2 writing established with ESL settings in mind may not be sufficient to address local exigencies of L2 writing in many EFL contexts and increasingly diversifying ESL settings. The study also invites L2 writing teachers to develop a better understanding of the range of diversity among student populations
What's so simple about simplified texts? A computational and psycholinguistic investigation of text comprehension and text processing
This study uses a moving windows self-paced reading task to assess both text comprehension and processing time of authentic texts and these same texts simplified to beginning and intermediate levels. Forty-eight second language learners each read 9 texts (3 different authentic, beginning, and intermediate level texts). Repeated measures ANOVAs reported linear effects of text type on reading time (normalized for text length) and true/false comprehension scores indicating that beginning level texts were processed faster and were more comprehensible than intermediate level and authentic texts. The linear effect of text type on comprehension remained significant within an ANCOVA controlling for language proficiency (i.e., TOEFL scores), reading proficiency (i.e., Gates-MacGinitie scores), and background knowledge, but not for reading time. Implications of these findings for materials design, reading pedagogy, and text processing and comprehension are discussed
Online Hyperparameter Meta-Learning with Hypergradient Distillation
Many gradient-based meta-learning methods assume a set of parameters that do
not participate in inner-optimization, which can be considered as
hyperparameters. Although such hyperparameters can be optimized using the
existing gradient-based hyperparameter optimization (HO) methods, they suffer
from the following issues. Unrolled differentiation methods do not scale well
to high-dimensional hyperparameters or horizon length, Implicit Function
Theorem (IFT) based methods are restrictive for online optimization, and short
horizon approximations suffer from short horizon bias. In this work, we propose
a novel HO method that can overcome these limitations, by approximating the
second-order term with knowledge distillation. Specifically, we parameterize a
single Jacobian-vector product (JVP) for each HO step and minimize the distance
from the true second-order term. Our method allows online optimization and also
is scalable to the hyperparameter dimension and the horizon length. We
demonstrate the effectiveness of our method on two different meta-learning
methods and three benchmark datasets
Asymptomatic Middle East Respiratory Syndrome coronavirus infection using a serologic survey in Korea
OBJECTIVES The rates of asymptomatic infection with Middle East Respiratory Syndrome (MERS) coronavirus vary. A serologic study was conducted to determine the asymptomatic MERS infection rate in healthcare workers and non-healthcare workers by exposure status. METHODS Study participants were selected from contacts of MERS patients based on a priority system in 4 regions strongly affected by the 2015 MERS outbreak. A sero-epidemiological survey was performed in 1,610 contacts (average duration from exposure to test, 4.8 months), and the collected sera were tested using an enzyme-linked immunespecific assay (ELISA), immunofluorescence assay (IFA), and plaque reduction neutralization antibody test (PRNT). Among the 1,610 contacts, there were 7 ELISA-positive cases, of which 1 exhibited positive IFA and PRNT results. RESULTS The asymptomatic infection rate was 0.060% (95% confidence interval, 0.002 to 0.346). The asymptomatic MERS case was a patient who had been hospitalized with patient zero on the same floor of the hospital at the same time. The case was quarantined at home for 2 weeks after discharge, and had underlying diseases, including hypertension, angina, and degenerative arthritis. CONCLUSIONS The asymptomatic infection was acquired via healthcare-associated transmission. Thus, it is necessary to extend serologic studies to include inpatient contacts who have no symptoms
Characterization and source of fluorescent dissolved organic matter in the Western Arctic Ocean: new insights from the 2019 summer study
Increase in river discharge and seasonal primary production and decline in sea ice coverage in the Arctic Ocean in summer can significantly affect the distribution and composition of dissolved organic matter (DOM). This study aimed to enhance the current available knowledge about the impacts of environmental changes on the characteristics of DOM in the rapidly changing Arctic Ocean. Seawater samples were collected from the western Arctic Ocean during the summer of 2019 and analyzed for fluorescent DOM (FDOM), dissolved organic carbon (DOC), and stable oxygen isotope (Ī“18O) content in conjunction with biophysical properties. We identified two humic-like (C1 and C2) and one protein-like (C3) components using fluorescence excitation-emission matrix coupled with parallel factor (EEMāPARAFAC) analysis. Remarkably high intensities of humic-like FDOM were found in the upper halocline layer (32 < salinity < 33.5 psu, at depths between 50ā200 m) with high inorganic nutrient concentrations and low N* values, indicating that the humic-like FDOM was supplied from the shelf sediment. Furthermore, shoaling of the upper halocline layer brought high levels of humic-like FDOM to the euphotic zone, resulting in an increased probability of photodegradation of humic-like FDOM due to exposure to solar radiation in the surface layer. Tryptophan-like FDOM was positively correlated with river water fraction (friver) and riverine DOC but not with chlorophyll-a (Chl-a) and heterotrophic bacterial abundance, indicating river discharge as a potential additional source of tryptophan-like FDOM. The correlation coefficients between tryptophan-like FDOM and river water parameters (friver and riverine DOC) differed across the Chukchi Sea, Chukchi Borderland, and East Siberian Sea, implying that the influence of river discharge on tryptophan-like FDOM is region-dependent. An increase in river discharge in future might lead to a greater supply of tryptophan-like FDOM, impacting the dynamics of DOM cycling in the western Arctic Ocean
Peri-implant bone length changes and survival rates of implants penetrating the sinus membrane at the posterior maxilla in patients with limited vertical bone height
PURPOSE: The aim of this study was to measure the peri-implant bone length surrounding implants that penetrate the sinus membrane at the posterior maxilla and to evaluate the survival rate of these implants.METHODS: Treatment records and orthopantomographs of 39 patients were reviewed and analyzed. The patients had partial edentulism at the posterior maxilla and limited vertical bone height below the maxillary sinus. Implants were inserted into the posterior maxilla, penetrating the sinus membrane. Four months after implant insertion, provisional resin restorations were temporarily cemented to the abutments and used for one month. Then, a final impression was taken at the abutment level, and final cement-retained restorations were delivered with mutually protected occlusion. The complications from the implant surgery were examined, the number of failed implants was counted, and the survival rate was calculated. The peri-implant bone lengths were measured using radiographs. The changes in initial and final peri-implant bone lengths were statistically analyzed.RESULTS: Nasal bleeding occurred after implant surgery in three patients. No other complications were found. There were no failures of the investigated implants, resulting in a survival rate of 100%. Significantly more bone gain around the implants (estimated difference=-0.6 mm, P=0.025) occurred when the initial residual bone height was less than 5 mm compared to the >5 mm groups. No significant change in peri-implant bone length was detected when the initial residual bone height was 5 mm or larger.CONCLUSIONS: This study suggests that implants penetrating the sinus membrane at the posterior maxilla in patients with limited vertical bone height may be safe and functional.Purpose : The aim of this study was to measure the peri-implant bone length surrounding implants that penetrate the sinus membrane at the posterior maxilla and to evaluate the survival rate of these implants.
Methods : Treatment records and orthopantomographs of 39 patients were reviewed and analyzed. The patients had partial edentulism at the posterior maxilla and limited vertical bone height below the maxillary sinus. Implants were inserted into the posterior maxilla, penetrating the sinus membrane. Four months after implant insertion, provisional resin restorations were temporarily cemented to the abutments and used for one month. Then, a final impression was taken at the abutment level, and final cement-retained restorations were delivered with mutually protected occlusion. The complications from the implant surgery were examined, the number of failed implants was counted, and the survival rate was calculated. The peri-implant bone lengths were measured using radiographs. The changes in initial and final peri-implant bone lengths were statistically analyzed.
Results : Nasal bleeding occurred after implant surgery in three patients. No other complications were found. There were no failures of the investigated implants, resulting in a survival rate of 100%. Significantly more bone gain around the implants (estimated difference=-0.6 mm, P=0.025) occurred when the initial residual bone height was less than 5 mm compared to the >5 mm groups. No significant change in peri-implant bone length was detected when the initial residual bone height was 5 mm or larger.
Conclusions : This study suggests that implants penetrating the sinus membrane at the posterior maxilla in patients with limited vertical bone height may be safe and functional.This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (No. 2011-0007662).OAIID:oai:osos.snu.ac.kr:snu2013-01/102/2008003883/6SEQ:6PERF_CD:SNU2013-01EVAL_ITEM_CD:102USER_ID:2008003883ADJUST_YN:NEMP_ID:A078517DEPT_CD:861FILENAME:J Periodontol Implant Sci 201304 43(2) 58-63.pdfDEPT_NM:ģ¹ģķź³¼EMAIL:[email protected]_YN:NCONFIRM:
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