Korean jogiyuhaksaeng's early study abroad and bilingual development in Australia

University of Technology, Sydney. Faculty of Arts and Social Sciences.The local processes of globalisation that have contributed to the heightened symbolic value of English in Korean society have seen an overwhelming desire for English acquisition, termed English fever. For Koreans, good English means a native-like fluency and accent which can be accomplished only by starting early with submersion in an English monolingual environment among native speakers. Jogiyuhak (early study abroad) is an embodiment of the prevalent belief that this is the best way to achieve good English with which students expected to become fluent bilinguals. Through narrative inquiry, this research examines 14 Korean youths’ lived experiences in study abroad in Australia, with a focus on academic and language development. The thesis traces the participants’ development trajectories in academic, linguistic and social adaptation, and explores self-evaluated bilinguality and their sense of inbetweenness in association with the ‘neither-language-is-fully-developed’ perception. The data show that language barriers not only impeded their initial adjustment but also had long term consequences, placing a severe constraint on pursuing academic inquiry in heavily language-dependent fields. The lack of both language repertoires and the associated feeling of discomfort that some participants revealed were related to this consequence. While such findings indicate a problematic bilinguality and a potentially significant risk of jogiyuhak, the data analysis reveals complex and varying bilingualities across individuals, suggesting that their bilingualities were constructed through their transnational life history and that language proficiency should be viewed as such rather than a set of linguistic skills. A deep analysis of the ‘lack of both language repertoires’ perception further reveals the social and ideological aspects of bilinguality. The discursively constructed bilinguality informs the aspects of language as sharedness and membership, suggesting the locally constructed nature of language proficiency and that inbetweenness was related to their transnationality. The ‘lack of language repertoires’ perception was also derived from the idealised notion of native speakers from both Korean and Australian contexts based on the monolithic and racialised view of language, culture and identity. These language ideologies were fundamentally based on an ontological view of language; language as a fixed entity and hence an object of possession. This thesis argues that such an ontological view of language is not only misleading in the process of language learning but also reproduces and perpetuates a deficit view of a language learner and a hierarchical stratification in relation to English. Alternatively, the thesis suggests that language should be viewed as social practices in particular locations, rather than a set of skills separate from what one does

EEG findings of reduced neural synchronization during visual integration in schizophrenia

Schizophrenia patients exhibit well-documented visual processing deficits. One area of disruption is visual integration, the ability to form global objects from local elements. However, most studies of visual integration in schizophrenia have been conducted in the context of an active attention task, which may influence the findings. In this study we examined visual integration using electroencephalography (EEG) in a passive task to elucidate neural mechanisms associated with poor visual integration. Forty-six schizophrenia patients and 30 healthy controls had EEG recorded while passively viewing figures comprised of real, illusory, or no contours. We examined visual P100, N100, and P200 event-related potential (ERP) components, as well as neural synchronization in the gamma (30-60 Hz) band assessed by the EEG phase locking factor (PLF). The N100 was significantly larger to illusory vs. no contour, and illusory vs. real contour stimuli while the P200 was larger only to real vs. illusory stimuli; there were no significant interactions with group. Compared to controls, patients failed to show increased phase locking to illusory versus no contours between 40-60 Hz. Also, controls, but not patients, had larger PLF between 30-40 Hz when viewing real vs. illusory contours. Finally, the positive symptom factor of the BPRS was negatively correlated with PLF values between 40-60 Hz to illusory stimuli, and with PLF between 30-40 Hz to real contour stimuli. These results suggest that the pattern of results across visual processing conditions is similar in patients and controls. However, patients have deficits in neural synchronization in the gamma range during basic processing of illusory contours when attentional demand is limited

Tunable surface plasmons of dielectric core-metal shell particles for dye sensitized solar cells

Our findings show that the extinction spectrum of core-shell type plasmonic particles can be effectively controlled by changing their geometric factor. This tuning capability allows the surface plasmons of the core-shell particles to be designed in such a way that the absorption of dye molecules is maximized in dye sensitized solar cells. When plasmonic particles with a metallic nanoshell and a dielectric core are incorporated into a TiO2 mesoporous photoelectrode, the optical cross section of dye sensitizers and the energy conversion efficiency of dye-sensitized solar cells (DSSCs) are increased. The enhanced photon-electron conversion is attributed to localized surface plasmons of the core-shell particles, which increase the absorption and scattering of incoming light in the photoelectrode. © 2013 The Royal Society of Chemistry

Reconsolidation of appetitive memories for both natural and drug reinforcement is dependent on B-adrenergic receptors

We have investigated the neurochemical mechanisms of memory reconsolidation and, in particular, the functional requirement for intracellular mechanisms initiated by beta-adrenergic signaling. We show that propranolol, given in conjunction with a memory reactivation session, can specifically disrupt the conditioned reinforcing properties of a previously appetitively reinforced conditioned stimulus (CS), whether the stimulus had been associated with self-administered cocaine or with sucrose. These data show that memories for both drug and nondrug CS-US associations are dependent on beta-adrenergic receptor-mediated signaling for their reconsolidation, with implications for the potential development of a novel treatment for drug addiction and some forms of obesity

Epidemiology of reemerging scarlet fever, Hong Kong, 2005–2015

The annual incidence rate of scarlet fever in Hong Kong remained elevated after an upsurge in 2011, increasing from 3.3 per 10,000 children aged ≤5 years during 2005–2010 to 18.1 during 2012–2015. Incidence was higher among boys and was 32%–42% lower in the week following school holidays.published_or_final_versio

An Excess of Jupiter Analogs in Super-Earth Systems

We use radial velocity observations to search for long-period gas giant companions in systems hosting inner super-Earth (1-4 R_Earth, 1-10 M_Earth) planets to constrain formation and migration scenarios for this population. We consistently re-fit published RV datasets for 65 stars and find 9 systems with statistically significant trends indicating the presence of an outer companion. We combine these RV data with AO images to constrain the masses and semi-major axes of these companions. We quantify our sensitivity to the presence of long-period companions by fitting the sample with a power law distribution and find an occurrence rate of 39+/-7% for companions 0.5-20 M_Jup and 1-20 AU. Half of our systems were discovered by the transit method and half were discovered by the RV method. While differences in RV baselines and number of data points between the two samples lead to different sensitivities to distant companions, we find that occurrence rates of gas giant companions in each sample are consistent at the 0.5$\sigma$ level. We compare the frequency of Jupiter analogs in these systems to the equivalent rate from field star surveys and find that Jupiter analogs are more common around stars hosting super-Earths. We conclude that the presence of outer gas giants does not suppress the formation of inner super-Earths, and that these two populations of planets instead appear to be correlated. We also find that the stellar metallicities of systems with gas giant companions are higher than those without companions, in agreement with the well-established metallicity correlation from RV surveys of field stars.Comment: published in A

Bubble generation mechanisms in microchannel under microgravity and heterogeneous wettability

Advances in hybrid surfaces have revealed interesting opportunities for multiphase flow control under microgravity, as the surface tension force is dominant in this condition. However, a comprehensive investigation of bubble generation rates and slug flow parameters remains challenging. This research integrates hybrid wettability and modified dynamic contact angle models to address this important knowledge gap. Using the computational capabilities of the IsoAdvector multiphase method, we performed detailed simulations of complex multiphase flow scenarios with the OpenFOAM package. We then validated these simulation results through rigorous comparison with available experimental data, thereby strengthening the accuracy and reliability of our numerical simulations. Our comprehensive research demonstrates the profound effect of altering contact angle distribution patterns on several critical parameters. These results highlight the precise control that can be achieved through the strategic manipulation of these patterns, offering the possibility of adjusting factors such as bubble production rate, slug length, bubble diameter, the relationship of flow residence to bubble movement, bubble movement speed in the channel, and pressure drop. Interestingly, altering these patterns can also induce asymmetric behavior in bubbles under microgravity conditions, a phenomenon that has significant implications for various applications. Such insights are crucial for fields such as heat transfer in energy systems, reaction mechanisms in chemical processes, multiphase flow control in petrochemical industries, fluid dynamics in aerospace engineering, and cooling mechanisms in electronic devices. With the ability to modulate these fundamental parameters, we gain valuable insights into the design and optimization of microchannel systems. Consequently, this research presents a more efficient and innovative approach to multiphase flow control, promising improved operational performance, and efficiency in various engineering applications

Laguerre–Gauss and Hermite–Gauss soft X-ray states generated using diffractive optics

Light’s capacity to carry angular momentum is integral to our knowledge of physics and ability to probe matter. In addition to spin, photons can occupy free-space orbital angular momentum eigenstates 1,2 . Visible light orbital angular momentum is used in quantum information experiments, super-resolution microscopy, optical tweezers and angular momentum transfer to atoms in optical lattices 3,4 . Soft X-ray orbital angular momentum applications, slowed by the lack of suitable optics and the rarity of coherent X-ray sources, could enable the direct alteration of atomic states through orbital angular momentum exchange, and methods to study the electronic properties of quantum materials. We have made soft X-ray diffractive optics that generate single Laguerre–Gauss modes, observed carrying up to 30ħ angular momentum per photon, or their superpositions. We also present Hermite–Gauss diffractive optics and a soft X-ray orbital angular momentum analyser. These tools could enable both the manipulation and finer characterization of topologically complex electronic matter, such as magnetic skyrmions

Numerical Investigation of the Plasma-Assisted MILD Combustion of a CH4/H2 Fuel Blend under Various Working Conditions

The effects of plasma injection upon MILD combustion of a mixture of methane and hydrogen are investigated numerically. The injected plasma includes the flow of a highly air-diluted methane including C2H2, C2H4, C2H6, CH, CH2, CH3, CO, and CO2. The results show that among all the constitutes of plasma, CH3 is the most effective in improving the characteristics of MILD combustion. Injection of this radical leads to the occurrence of reactions at a closer distance to the burner inlet and thus provides longer time for completion of combustion. Further, mass fractions of OH, CH2O, and HCO are considerably affected by the injections of CH3, indicating structural modifications of the reacting flow. Importantly, as Reynolds number of the plasma flow increases, the volume and width of the flame decrease, while the formations of prompt and thermal NOx are intensified. However, injection of CH3, as plasma, reduces the emission of thermal NOx