2,163 research outputs found
“It’s not real culture anyway”: Language ideologies of local and expatriate English teachers in rural South Korea
In South Korea (Korea), Park (2004) identifies three dominant English language ideologies: necessity (English as essential to compete in neoliberal markets), externalization (English as antithetical to Korean identity), and self-deprecation (English as unobtainable by Korean speakers). While studies have explored these ideologies among Korean English teachers in cosmopolitan settings like Seoul, few studies consider how teachers in rural areas negotiate these language ideologies. This study compares ideological stances from both expatriate guest English teachers (GETs) and local Korean English teachers (LETs). Participants working in the rural province of Jeollanamdo conducted semi-structured interviews about their perspectives and experiences regarding English education in Korea. Interviews underwent thematic analysis where initial codes identified Park’s three ideologies, and further coding produced subthemes through stance analysis. Findings indicate a diverse mix of stances between LETs and GETs that both affirm and resist dominant English language ideologies. LETs and GETs with experience working in both rural islands and coastal cities also report variation in students’ motivation and stress toward English education. By examining variation in teachers’ stancetaking toward dominant English language ideologies, this study challenges Bourdieu’s (1991) notion of a unified linguistic ideological marketplace
Language Ideologies in Deep South Korea: Voices of Jeollanamdo English Teachers
Language ideologies serve as shared beliefs and key frames that link language and society, mediating both macro-level social forces and micro-level interactions. Through this lens, this thesis compares the ideological perspectives and experiences of expatriate and local English teachers working in secondary-level schools in the rural province of Jeollanamdo, South Korea. Through thematic analysis of semi-structured interviews, this study argues for complexity and nuance in how language teachers from distinct backgrounds perceive and negotiate dominant English language ideologies in Korean society. Moreover, these ideological perspectives differ between teachers of local and expatriate backgrounds, or teachers working in urban and rural areas. This study aims to challenge notions of metronormativity and unified ideological marketplaces by sharing the voices of English teachers in an understudied province of Korea. Furthermore, this thesis provides a comparison between macro-level theories of language ideology and linguistic political economy and the micro-level experiences and perspectives of individual educators
Collagen attachment to the substrate controls cell clustering through migration
Cell clustering and scattering play important roles in cancer progression and tissue engineering. While the extracellular matrix (ECM) is known to control cell clustering, much of the quantitative work has focused on the analysis of clustering between cells with strong cell-cell junctions. Much less is known about how the ECM regulates cells with weak cell-cell contact. Clustering characteristics were quantified in rat adenocarcinoma cells, which form clusters on physically adsorbed collagen substrates, but not on covalently attached collagen substrates. Covalently attaching collagen inhibited desorption of collagen from the surface. While changes in proliferation rate could not explain differences seen in the clustering, changes in cell motility could. Cells plated under conditions that resulted in more clustering had a lower persistence time and slower migration rate than those under conditions that resulted in less clustering. Understanding how the ECM regulates clustering will not only impact the fundamental understanding of cancer progression, but also will guide the design of tissue engineered constructs that allow for the clustering or dissemination of cells throughout the construct
The Number of Lines a Cell Contacts and Cell Contractility Drive the Efficiency of Contact Guidance
Cell migration is an important biological function that impacts many physiological and pathological processes. Often migration is directed along various densities of aligned fibers of collagen, a process called contact guidance. However, cells adhere to other components in the extracellular matrix, possibly affecting migrational behavior. Additionally, changes in intracellular contractility are well known to affect random migration, but its effect on contact guidance is less known. This study examines differences in directed migration in response to variations in the spacing of collagen, non-specific background adhesion strength and myosin II-mediated contractility. Collagen was microcontact printed onto glass substrates and timelapse live-cell microscopy was used to measure migration characteristics. Increasing the number of lines a cell contacts or decreasing contraction led to decreases in directionality, but speed changes were context dependent. This suggests that while cell migration speed is a biphasic function of contractility, directionality appears to be a monotonic, increasing function of contractility. Thus, increasing the number of lines a cell contacts or decreasing contractility degrades the contact guidance fidelity
Matrix metalloproteinase-14 is a mechanically regulated activator of secreted MMPs and invasion
Matrix metalloproteinases (MMPs) are extracellular matrix (ECM) degrading enzymes and have complex and specific regulation networks. This includes activation interactions, where one MMP family member activates another. ECM degradation and MMP activation can be initiated by several different stimuli including changes in ECM mechanical properties or intracellular contractility. These mechanical stimuli are known enhancers of metastatic potential. MMP-14 facilitates local ECM degradation and is well known as a major mediator of cell migration, angiogenesis and invasion. Recently, function blocking antibodies have been developed to specifically block MMP-14, providing a useful tool for research as well as therapeutic applications. Here we utilize a selective MMP-14 function blocking antibody to delineate the role of MMP-14 as an activator of other MMPs in response to changes in cellular contractility and ECM stiffness. Inhibition using function blocking antibodies reveals that MMP-14 activates soluble MMPs like MMP-2 and -9 under various mechanical stimuli in the pancreatic cancer cell line, Panc-1. In addition, inhibition of MMP-14 abates Panc-1 cell extension into 3D gels to levels seen with non-specific pan-MMP inhibitors at higher concentrations. This strengthens the case for MMP function blocking antibodies as more potent and specific MMP inhibition therapeutics
PID-Inspired Inductive Biases for Deep Reinforcement Learning in Partially Observable Control Tasks
Deep reinforcement learning (RL) has shown immense potential for learning to
control systems through data alone. However, one challenge deep RL faces is
that the full state of the system is often not observable. When this is the
case, the policy needs to leverage the history of observations to infer the
current state. At the same time, differences between the training and testing
environments makes it critical for the policy not to overfit to the sequence of
observations it sees at training time. As such, there is an important balancing
act between having the history encoder be flexible enough to extract relevant
information, yet be robust to changes in the environment. To strike this
balance, we look to the PID controller for inspiration. We assert the PID
controller's success shows that only summing and differencing are needed to
accumulate information over time for many control tasks. Following this
principle, we propose two architectures for encoding history: one that directly
uses PID features and another that extends these core ideas and can be used in
arbitrary control tasks. When compared with prior approaches, our encoders
produce policies that are often more robust and achieve better performance on a
variety of tracking tasks. Going beyond tracking tasks, our policies achieve
1.7x better performance on average over previous state-of-the-art methods on a
suite of locomotion control tasks.Comment: NeurIPS 202
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