• Title/Summary/Keyword: Persistent current

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From Knowledge Arbitrager to Policy Entrepreneur? Exploring the Role of Think Tank in the Open Innovation System

  • Seo, Il Won;Asmara, Anugerah Yuka;Kwon, Ki-Seok
    • Asian Journal of Innovation and Policy
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    • v.10 no.3
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    • pp.316-329
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    • 2021
  • This study explores the role of the think tank as an intermediary organization in the open innovation system. Think tank has contributed to the policy process as a mediator between government and public and as a symbolic entity of intellectual innovation to produce knowledge to the public. As the innovation system matures, one of the major challenges in research and practice is the openness and collaboration in the science, technology, and innovation system. While previous literature highlighted the think tank as the knowledge arbitrager transforming ideas into policy issues, few studies address the research questions: Is the conventional role of the think tank still persistent in the open innovation system? What are the demanding roles? This paper tackles these questions by reviewing the current role of the South Korean think tank in the science & technology sector. Based on the open innovation framework, we suggest that think tanks need to play a bigger role as policy entrepreneurs, crossing policy borders and interacting with other partners.

Re-defining T-Cell Exhaustion: Subset, Function, and Regulation

  • Se Jin Im;Sang-Jun Ha
    • IMMUNE NETWORK
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    • v.20 no.1
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    • pp.2.1-2.19
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    • 2020
  • Acute viral infection or vaccination generates highly functional memory CD8 T cells following the Ag resolution. In contrast, persistent antigenic stimulation in chronic viral infection and cancer leads to a state of T-cell dysfunction termed T-cell exhaustion. We and other have recently identified a novel subset of exhausted CD8 T cells that act as stem cells for maintaining virus-specific CD8 T cells in a mouse model of chronic lymphocytic choriomeningitis virus infection. This stem cell-like CD8 T-cell subset has been also observed in both mouse and human tumor models. Most importantly, in both chronic viral infection and tumor models, the proliferative burst of Ag-specific CD8 T cells driven by PD-1-directed immunotherapy comes exclusively from this stem cell-like CD8 T-cell subset. Therefore, a better understanding of the mechanisms how CD8 T-cell subsets are regulated during chronic viral infection and cancer is required to improve the current immunotherapies that restore the function of exhausted CD8 T cells. In this review, we discuss the differentiation of virus-specific CD8 T cells during chronic viral infection, the characteristics and function of CD8 T-cell subsets, and the therapeutic intervention of PD-1-directed immunotherapy in cancer.

Firefighters and Posttraumatic Stress Disorder (소방공무원과 외상 후 스트레스 장애)

  • Ryu, Jia;Ha, Eunhee;Jeong-Choi, Kyunghee;Kim, Jieun E.;Park, Shinwon;Kim, Hyunjoo
    • Korean Journal of Biological Psychiatry
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    • v.24 no.1
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    • pp.10-18
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    • 2017
  • Occupational hazards of firefighting and rescue works include frequent exposure to emergencies and life-threatening situations. These stressful work conditions of being constantly under pressure and exposed to potentially traumatic events put them at higher risk of developing posttraumatic stress disorder (PTSD), compared to the general population. PTSD is a potentially debilitating mental disorder, due to persistent intrusive thoughts, negative alterations of mood and cognition, hypervigilance, avoidance of similar situations and reminders, and re-experiences of the traumatic event. Previous studies have shown a relatively high prevalence of PTSD among firefighters, indicating the need for a systematic approach of early detection and prevention. Therefore, a critical review of the current literature on PTSD in firefighters would provide valuable insights into developing effective prevention and intervention programs. Literature indicated that there are risk factors of PTSD in firefighters, such as pre-existing depression, anxiety, sleep disorders, occupational stress, physical symptoms, and binge drinking, whereas social support and adequate rewards are protective factors. Although there are differences in the prevalence of PTSD across studies, partly due to various assessment tools utilized, different sample sizes, and sample characteristics, over one tenth of the firefighters were estimated to have PTSD. The current review warrants further investigations to precisely assess PTSD and co-morbid mental disorders, functional outcomes, and associated factors, and to develop evidence-based preventive and interventional programs to help firefighters with PTSD.

Evaluation of Wet-Mixed High Strength Sprayed Polymer Mortar for Fire Resistance (내화용 고강도 습식 스프레이 폴리머 모르타르의 화재 저항성 평가)

  • Won, Jong-Pil;Choi, Seok-Won;Park, Chan-Gi;Park, Hae-Kyun
    • Journal of the Korea Concrete Institute
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    • v.18 no.4 s.94
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    • pp.559-568
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    • 2006
  • The purpose of this study is to evaluate the mechanical performance and fire resistance of wet-mixed high strength sprayed polymer-modified mortar in order to protect tunnel lining system which are in the event of fire disaster. Since the current commercial fire-resistant materials reproduce the low strength issue of mortar, this study aims to provide an enhanced fire-resistant mortar with a proper strength. Normally, a large temperature gradient phenomenon arise in the vicinity of free surfaces which are fully exposed in the event of persistent flame. Thereby, the determination of optimal cover depth of wet-mixed high strength sprayed polymer-mortar(WHSPM) is important for fire-resistance of tunnel lining system. With comparison of current commercial fire-resistance materials and WHSPM, the experimental result of WHSPM shows the better fire-resistant performance than the others. In addition, the cover limitation should be controlled by minimum 4cm depth in order to avoid fire-induced damage.

Current Insights into Research on Rice stripe virus

  • Cho, Won Kyong;Lian, Sen;Kim, Sang-Min;Park, Sang-Ho;Kim, Kook-Hyung
    • The Plant Pathology Journal
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    • v.29 no.3
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    • pp.223-233
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    • 2013
  • Rice stripe virus (RSV) is one of the most destructive viruses of rice, and greatly reduces rice production in China, Japan, and Korea, where mostly japonica cultivars of rice are grown. RSV is transmitted by the small brown plant-hopper (SBPH) in a persistent and circulative-propagative manner. Several methods have been developed for detection of RSV, which is composed of four single-stranded RNAs that encode seven proteins. Genome sequence data and comparative phylogenetic analysis have been used to identify the origin and diversity of RSV isolates. Several rice varieties resistant to RSV have been selected and QTL analysis and fine mapping have been intensively performed to map RSV resistance loci or genes. RSV genes have been used to generate several genetically modified transgenic rice plants with RSV resistance. Recently, genome-wide transcriptome analyses and deep sequencing have been used to identify mRNAs and small RNAs involved in RSV infection; several rice host factors that interact with RSV proteins have also been identified. In this article, we review the current statues of RSV research and propose integrated approaches for the study of interactions among RSV, rice, and the SBPH.

Roles of Reactive Oxygen Species on Neuronal Excitability in Rat Substantia Gelatinosa Neurons (척수 아교질 신경세포의 흥분성에 대한 활성산소종의 역할)

  • Choi, Jeong-Hee;Kim, Jae-Hyo;Lim, Sung-Jun;Park, Byung-Rim;Kwon, Kang-Beom
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.21 no.2
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    • pp.432-437
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    • 2007
  • Reactive oxygen species (ROS) are toxic agents that may be involved in various neurodegenerative diseases. Recent studies indicate that ROS are also involved in persistent pain through a spinal mechanism. In the present study, whole cell patch clamp recordings were carried out on substantia gelatinosa (SG) neurons in spinal cord slice of neonatal rats to investigate the effects of ROS on neuronal excitability and excitatory synaptic transmission. In current clamp condition, tert-buthyl hydroperoxide (t-BuOOH), an ROS donor, induced a electrical hyperexcitability during t-BuOOH wash-out followed by a brief inhibition of excitability in SG neurons. Application of t-BuOOH depolarized membrane potential of SG neurons and increased the neuronal firing frequencies evoked by depolarizing current pulses. Phenyl-N-tert-buthylnitrone (PBN), an ROS scavenger, antagonized t-BuOOH induced hyperexcitability. IN voltage clamp conditions, t-BuOOH increased the frequency and amplitude of spontaneous excitatory postsynaptic currents (sEPSCs). In order to determine the site of action of t-BuOOH, miniature excitatory postsynaptic currents (mEPSCs) were recorded. t-BuOOH increased the frequency and amplitude of mEPSCs, indicating that it may modulate the excitability of the SG neurons via pre- and postsynaptic actions. These data suggest that ROS generated by peripheral nerve injury can induce central sensitization in spinal cord.

Current CRM Adoption in Korean Apparel Industry (국내 의류업체의 CRM 도입현황)

  • Ko, Eun-Ju
    • Journal of the Korean Society of Clothing and Textiles
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    • v.30 no.1 s.149
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    • pp.1-11
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    • 2006
  • The purpose of this study was to analyze the current CRM situation in Korean apparel industry. Specifically, research purposes were 1) to examine the concepts and benefits of CRM, 2) to examine CRM strategies, 3) to analyze CRM system(i.e., customer relationship management service, customer segmentation criteria, DB management system), and 4) to analyze the potential problems and CRM adoption plan. The subjects for this research were thirty CRM managers in Korean apparel firms classified by the company type(woman's wear, man's wear, casual wear, children's wear, retailer) interviewed from December 2003 to March 1004. The results of this study were as follows: First, the concept of CRM represented the prime customer relationship, continuous consideration, and customer management system. The benefits of CRM reflected re-sales, improvement of profit share, and acquisition of customer's data base. Second, concerning the CRM strategies, most companies focused on persistent customer management through mileage program, membership cards and also implemented product strategies such as demand forecasting, customization based on customer data analysis. We also found that industry preferred to use pricing strategies, for example, segmentation of customer through discrepancies of price in which customers are provided by discount and gift voucher services. Regarding distribution strategy, channel diversification, localized service, and convenient delivery system were used. As promotion strategies, they chose celebrating customers' personal events and promoting cultural events and issuing coupons. Third, regarding CRM system, information service was the most frequently adopted, important and highly beneficial category. Also POS/web-POS, homepage were main sources of information. RFM is the mostly commonly used customer segmentation criteria. Fourth, potential problems in CRM adoption were lack of CRM knowledge and performance measurement of CRM. Future CRM adoption plan included CRM education and development of CRM performance measures.

Photoconductivity in Mg-doped p-type GaN by MBE

  • ;;;;;Yuldashev
    • Proceedings of the Korean Vacuum Society Conference
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    • 1999.07a
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    • pp.120-120
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    • 1999
  • III-nitride계 물질들은 blue와 UV 영역의 LED, LD와 같은 광소자뿐만 아니라 HBT, FET와 같은 전자소자로도 널리 응용되고 있다. 이와 같은 물질을 이용한 소자를 제작할 수 있는 낮은 저항의 ohmic contact은 필수적이다. Al이나 Ti와 같은 물질을 기초로 한 n-GaN의 경우는 이미 많은 연구결과가 발표되어 전기적 광학적 소자를 동작하는데 충분히 낮은 ohmic contact저항( )을 었다. 그러나 p-GaN의 ohmic contact은 아직까지 많은 문제점을 내포하고 있다. 그 중의 하나는 높은 doping 농도( )의 p-GaN 박막을 성장하기가 어렵다는 것이며, 또 하나는 낮은 접촉 비저항을 얻기 위해선 7.5eV이상의 큰 재가 function을 지닌 금속을 선택해야 한다. 그러나 5.5eV 이상의 재가 function을 갖는 금속은 존재하지 않는다. 위와 같은 문제점들은 p-GaN의 접촉 비저항이 이상의 높은 값을 갖게 만들고 있으며, 이에 대한 해경방안으로는 고온의 열처리를 통하여 p-GaN와 금속 사이에서 화학적 반응을 일으킴으로써 표면 근처에서 캐리어농도를 증가시키고, 캐리어 수송의 형태가 tunneling 형태로 일어날 수 있도록 하는 tunneling current mechanism을 이용하는 것이다. 이로 인해 결국 낮은 접촉 비저항을 얻을 수 있게되며, 일반적으로 p-GaN에서는 Nidl 좋은 물질로 알려져 있다. 그러나 Ni은 50$0^{\circ}C$이상의 열처리에서 쉽게 산화되는 특성 때문에 높은 캐리어를 얻는데 어려운 문제점이 있다. 이에 본 연구에서는 MBE로 성장된 p-GaN박막을 Mg의 activation을 더욱 증가시키기 위해 N2 분위기에서 15분간 90$0^{\circ}C$에서 annealing을 하였으며, ohmic 접촉을 위한 금속으로 높은 재가 function과 좋은 adhesion 그리고 낮은 자체저항을 가지고 있는 Ni/Au를 ohmic metal로 하여 contact한 후에 90$0^{\circ}C$에서 10초간 rapid thermal annealing (RTA)처리를 했다. 성장된 박막의 광학적 성질은 PL로써 측정하였으며, photoconductivity 실험을 통해 impurity의 life time을 분석하였고, persistent photoconductivity를 통해 dark current를 측정하였다. 또한 contact resistance를 계산하기 위해 circular-TLM method을 이용하여 I-V 특성을 조사하였다.

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Job Creation in the Social Service Sector : A Critical Review of the Current Problems and the New Administration's Policies (사회서비스 10년 경험을 통해 본 사회서비스 일자리 정책의 과제)

  • Yoo, Tae Kyun
    • Korean Journal of Social Welfare Studies
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    • v.49 no.1
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    • pp.29-50
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    • 2018
  • Since 2006, the Korean government has introduced a series of policies to create social service related jobs. Facing the new social risk of Jobless Growth, the newly launched Moon Jae-In administration had no choice but to include job creation in the social service sector as one of the 100 National Tasks for the next five years. The primary purpose of this study is to provide based on the last 10 years' experience a critical analysis of the new government's social service job creation policies. It has been proven that containing budget growth and creating jobs are not compatible goals. The government's control over social service prices has been persistent for the last 10 years serving the purpose of containing social service budget. The author argues that low quality jobs and depressed social service market are the results of such policy. The current problems created by the past policies and a number of new problems that the new government's plan to establish so-called Social Service Corporation might create are discussed, and a set of policy tasks including a social insurance for social services are suggested as alternative solutions for the old and new problems.

Assimilation of Satellite-Based Soil Moisture (SMAP) in KMA GloSea6: The Results of the First Preliminary Experiment (기상청 GloSea의 위성관측 기반 토양수분(SMAP) 동화: 예비 실험 분석)

  • Ji, Hee-Sook;Hwang, Seung-On;Lee, Johan;Hyun, Yu-Kyung;Ryu, Young;Boo, Kyung-On
    • Atmosphere
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    • v.32 no.4
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    • pp.395-409
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    • 2022
  • A new soil moisture initialization scheme is applied to the Korea Meteorological Administration (KMA) Global Seasonal forecasting system version 6 (GloSea6). It is designed to ingest the microwave soil moisture retrievals from Soil Moisture Active Passive (SMAP) radiometer using the Local Ensemble Transform Kalman Filter (LETKF). In this technical note, we describe the procedure of the newly-adopted initialization scheme, the change of soil moisture states by assimilation, and the forecast skill differences for the surface temperature and precipitation by GloSea6 simulation from two preliminary experiments. Based on a 4-year analysis experiment, the soil moisture from the land-surface model of current operational GloSea6 is found to be drier generally comparing to SMAP observation. LETKF data assimilation shows a tendency toward being wet globally, especially in arid area such as deserts and Tibetan Plateau. Also, it increases soil moisture analysis increments in most soil levels of wetness in land than current operation. The other experiment of GloSea6 forecast with application of the new initialization system for the heat wave case in 2020 summer shows that the memory of soil moisture anomalies obtained by the new initialization system is persistent throughout the entire forecast period of three months. However, averaged forecast improvements are not substantial and mixed over Eurasia during the period of forecast: forecast skill for the precipitation improved slightly but for the surface air temperature rather degraded. Our preliminary results suggest that additional elaborate developments in the soil moisture initialization are still required to improve overall forecast skills.