처녀자리은하단과 M85의 구상성단계

학위논문 (박사)-- 서울대학교 대학원 자연과학대학 물리·천문학부, 2017. 8. 이명균.This thesis presents a study of the globular clusters (GCs) in the Virgo cluster and M85 based on the comprehensive photometric and spectroscopic surveys. The GCs are of great use to trace the formation and evolution history of their host environments. We investigate the origin of intracluster GCs (IGCs) in the Virgo cluster as well as the GCs in the merger remnant galaxy M85. We present the results of a wide-field spectroscopic survey of GCs in the Virgo cluster. We obtain spectra for 201 GCs and 55 ultracompact dwarfs (UCDs) using Hectospec on the Multiple-Mirror Telescope and derive their radial velocities. We identify 46 genuine IGCs, not associated with any Virgo galaxies, using the 3D GMM test on the spatial and radial velocity distribution. They are located at a projected distance 200 kpc < R < 500 kpc from the center of M87. The radial velocity distribution of these IGCs shows two peaks, one at vr =1023 km s−1, associated with the Virgo main body, and another at vr = 36 km s−1, associated with the infalling structure. The velocity dispersion of the IGCs in the Virgo main body is sigma_IGC ∼ 314 km s−1, which is smoothly connected to the velocity dispersion profile of M87 GCs but is much lower than that of dwarf galaxies in the same survey field, sigma_dwarf ∼ 608 km s−1. The UCDs are more centrally concentrated on massive galaxies–M87, M86, and M84. The radial velocity dispersion of the UCD system is much smaller than that of dwarf galaxies. Our results confirm the large-scale distribution of Virgo IGCs indicated by previous photometric surveys. The color distribution of the confirmed IGCs shows a bimodality similar to that of M87 GCs. This indicates that most IGCs are stripped off dwarf galaxies and some off massive galaxies in the Virgo. M85 is one of nearby merger remnant galaxies that underwent merging events a few Gyrs ago. The GCs in M85 are surveyed with the MegaCam attached at 3.6m Canada-French-Hawaii telescope. We obtain ugi-band images of 1◦× 1◦ field around M85.We identify 1318 GC candidates among point sources in the survey region using color and magnitude criteria. The GC candidates are well concentrated on M85 but show more extended spatial distribution than the galaxy light. The effective radius of the entire GC system is about 5.′54, corresponding to 29 kpc. The color distribution of the GC candidates shows two peaks of (g−i)0 = 0.65 and 0.87. We detect the green GC population in the inner region R < 2' in addition to blue and red GC populations. The radial number density profile and the surface number density map of the blue GC system show more extended features than those of red GC system. The effective radii of the blue and red GC systems are 7.'41 and 2.'31, respectively. The spatial distributions of both blue and red GC systems are elongated, which are similar to galaxy light. This feature differs from that shown in typical early-type galaxies. We suggest that the presence of the green GCs and the elongated spatial distribution of the blue and red GC systems are merger-induced features. We present the first spectroscopic study of GCs in the merger remnant galaxy M85 using two instruments: Gemini Multi-Object Spectrograph (GMOS) attached at the 8.1m Gemini-North telescope and Hectospec on the 6.5m Multiple-Mirror Telescope. We obtain the spectra for 20 GCs as well as the nucleus of M85 using the Gemini/GMOS. The radial velocities of the GCs range from 396 km s−1 to 1127 km s−1, which is consistent with that of the M85 nucleus (vr = 743 ± 8 km s−1). We find a signal of rotation of M85 GC system, and estimate their rotation-corrected radial velocity dispersion as 154 km s−1. The ages and metallicities of the GCs are derived from Lick indices and full spectrum fitting. We detect the intermediate-age population of which mean age is 4.0 ± 2.0 Gyr with solar metallicities ([Fe/H] ∼ –0.19), comprising 50% of the observed GCs, as well as old population. This suggests that M85 experienced a wet merging event about 4 Gyrs ago. In addition, we obtain the spectra for 53 GCs including 11 IGCs using the MMT/Hectospec. The radial velocities of the GCs range from ∼ 400 km s−1 to ∼ 1600km s−1. We classify the GC sample into three categories, blue and red GCs in M85, and IGCs. We select the GCs that belong to M85 with two criteria: vr < 1200 km s−1 and R < 20', and the other GCs are considered as IGCs. The color criterion (g−i)0 = 0.8 is used to divide the M85 GCs into blue and red ones. All red GCs are located within R < 6', while the blue ones are distributed to R ∼ 20'. We investigate the kinematics of the GC system of M85. The entire M85 GC system shows overall rotation as shown in the GC sample of GMOS observation. The red GC system shows more clear rotation feature than the blue GC system despite the small sample. The rotation axis of the GC system of M85 is clearly different from that of the central galaxy light. We derive the rotation-corrected radial velocity dispersion of two GC systems: sigma_r = 149 ± 20 km s−1 for blue GCs and sigma_r = 51 ± 14 km s−1 for red GCs. The rotation-corrected velocity dispersion of red GC system is much lower than that of blue GC system. The strong rotation feature of the GC system and kinematically decoupled GC system from the stellar light are suspected to be caused by merging events. The kinematics of the M85 GCs and IGCs are clearly different from each other. The mean radial velocities of M85 GCs and IGCs are 765 ± 27 km s−1 and 1012 ± 108 km s−1, respectively. The radial velocity dispersion of the IGCs is 354 ± 78 km s−1, which is higher than that of the M85 GCs and similar to that of dwarf galaxies in the survey region (sigma = 330±95 km s−1). This indicates that the IGCs are governed by the gravitational potential of the galaxy cluster.1 Introduction 1 1.1 Globular Clusters 1 1.2 GCs in Early-type Galaxies 2 1.3 GCs in Interesting Environments 4 1.3.1 Wandering GCs 4 1.3.2 GCs in Merger Remnant Galaxies 5 1.4 IGCs in the Virgo 6 1.5 GCs in M85 6 1.6 Purpose and Outline of the Thesis 8 2 To the Edge of M87 and Beyond: Spectroscopy of IGCs and Ultra Compact Dwarfs in the Virgo Cluster 11 2.1 Introduction 11 2.2 Observation and Data Reduction 14 2.2.1 Target Selection for Spectroscopy 14 2.2.2 Spectroscopic Observation 16 2.2.3 Data Reduction and Radial Velocity Measurement 18 2.3 Results 19 2.3.1 Construction of GC and UCD samples 19 2.3.2 Radial Velocity and Velocity Dispersion Profiles of GCs and UCDs 40 2.4 Discussion 48 2.4.1 The Number of Virgo IGCs 48 2.4.2 Color Distribution of IGCs 50 2.4.3 Dynamical State of the Virgo Cluster 54 2.4.4 The Origin of Virgo UCDs 56 2.5 Summary 61 3 A Wide-field Photometry of GCs in the Merger Remnant Galaxy M85 65 3.1 Introduction 65 3.2 Observation and Data Reduction 67 3.2.1 Observation 67 3.2.2 Photometry and Standard Calibration 68 3.3 Results 68 3.3.1 GC Selection 68 3.3.2 Surface density of GC candidates 70 3.3.3 Color Distribution of GCs 76 3.3.4 Radial trend of GC colors 80 3.3.5 Surface density of BGCs and RGCs 83 3.4 Discussion 85 3.4.1 Substructures of M85 GC system 85 3.4.2 Merging Signatures on M85 GC system 88 3.5 Summary 90 4 Ages and Metallicities of GCs in the Merger Remnant Galaxy M85 91 4.1 Introduction 91 4.2 Observation and Data Reduction 93 4.2.1 Target Selection for Spectroscopy 93 4.2.2 Spectroscopic Observation and Data Reduction 93 4.3 Radial Velocity Measurements and Membership 97 4.4 Age, [Z/H], and [alpha/Fe] Measurements 100 4.4.1 Lick Indices 100 4.4.2 Full Spectrum Fitting 103 4.5 Results 104 4.5.1 Comparison of Parameters Derived From Different Methods 104 4.5.2 Age and Metallicity Distribution of M85 GCs 110 4.5.3 Kinematics of the GC System in M85 114 4.6 Discussion 115 4.6.1 Kinematically Decoupled System Between GCs and Stellar Light 115 4.6.2 Merging History of M85 120 4.7 Summary 121 5 A Wide-field Spectroscopy of the GC System of the Merger Remnant Galaxy M85 123 5.1 Introduction 123 5.2 Observation and Data Reduction 125 5.2.1 Target Selection for Spectroscopy 125 5.2.2 Spectroscopic Observation and Data Reduction 125 5.2.3 Radial Velocity Measurements 129 5.3 Results 129 5.3.1 GC Selection and Membership Determination 129 5.3.2 Kinematics of the GC System in M85 132 5.4 Discussion 140 5.4.1 Rotation of the GC System of M85 140 5.4.2 Kinematics of IGCs 144 5.4.3 Dynamical Mass of M85 145 5.5 Summary 147 6 Summary and Conclusion 149 Bibliography 155 A Database for M85 GCs 167 요 약 211Docto

A study on understanding the determination factors of household debt in Korea using Single-Index Model

본 연구는 한국의 가계부채를 준모수적인 방법 중 하나인 단일지수모형을 이용하여 가구 단위로 분석하고자 한다. 본 연구의 목적은 분석을 통하여 지수 내 추정치의 결과를 확인하고 지수가 가계부채에 대해 어떤 함수를 갖게 되는지 확인하는 것이다. 분석은 2011년부터 2015년까지 각 연도에 대해서 진행되었다. 가구의 경제적 특성과 사회인구학적 특성을 종합하여 분석한 결과, 가구의 경제적 변수는 대체로 유의하게 나타났으나 사회인구학적 특성은 유의하지 않게 나타났다. 가구의 총 금융 자산은 소득과 같은 방향으로 가계 부채에 영향을 미치며 부동산 자산과 자가 주택의 시가는 소득과 반대 방향으로 가계 부채에 영향을 미치는 것이 발견되었다. ;The purpose of the study is to analyze the determination factors of the total household debt in the unit of household in Korea by using Single-Index model which is one of the semiparametric models. We analyze the coefficients of the index and the functional form of the index to household debt for each year, from 2011 to 2015. We use economic variables and socio-demographic variables of household as regressors. The economic variables, the total financial asset, the total real estate asset and the market price of housing are mostly significant. However, all of socio-demographic variables are not significant. The total financial asset affects the total household debt in the opposite direction of income. The total real estate asset and the market price of housing affect the total household debt in the same direction of income.Ⅰ. 서론 1 Ⅱ. 실증분석 3 A. 단일지수모형 3 B. 연구대상 및 자료수집 8 C. 실증분석 결과 9 Ⅲ. 결론 및 논의 19 참고문헌 20 부록 22 A. 기초통계분석 22 B. 자가 주택 보유 가구 대상에 대한 분석 결과 24 ABSTRACT 2

C/EBP α 와 PPARγ2와 상호작용을 통해 lipin1이 지방 세포의 분화와 유지에 영

Dept. of Medical Science/박사[한글] [영문]Lipin1 expression was induced at a late stage of differentiation of 3T3-L1 preadipocytes and maintained at high level in mature adipocytes. Knockdown of expression of lipin1 by small interfering RNA (siRNA) in 3T3-L1 preadipocytes almost completely inhibited differentiation into adipocytes, whereas overexpression of lipin1 accelerated adipocyte differentiation, demonstrating that lipin1 is required for adipocyte differentiation. In mature adipocytes, transfection of lipin1-siRNA decreased the expression of adipocyte functional genes, indicating the involvement of lipin1 in the maintenance of adipocyte function. Lipin1 increases the transcription-activating function of PPARγ2 via direct physical interaction, whereas lipin1 did not affect the function of other adipocyte-related transcription factors, such as C/EBPα, LXRα or SREBP-1c. In mature adipocytes, lipin1 was specifically recruited to the PPREs of the PEPCK gene, an adipocyte-specific gene. C/EBPα up-regulates lipin1 transcription by directly binding to the lipin1 promoter. Based on the existence of a positive feedback loop between C/EBPα and PPARγ2, we propose that lipin1 functions as an amplifier of the network between these factors, resulting in the maintenance of high levels of the specific gene expression that is required for adipogenesis and mature adipocyte functions.ope

Job analysis of the staff nurse in Cardiac Surgery Intensive Care Units.

간호학과/석사[한글] 본 연구는 서울시 및 경기도내 종합병원 심장외과 중환자실에서 근무하는 일반간호사가 실제 수행하고 있는 간호업무를 조사하고 분석함으로써 심장외과 중환자실 간호사 업무 표준의 설정과 간호업무 내용의 틀을 제시하기 위한 합리적인 제도를 마련하는데 필요한 기초 자료로 활용될 수 있도록 하기 위해 시도되었다. 구체적인 분석방법과 결과는 다음과 같다. 1. 심장외과 중환자실 일반간호사의 간호업무의 내용을 문헌고찰과 전문가집단의 검토를 통해 실제 심장외과 중환자실에서 수행되고 있는 간호활동을 규명하기 위해 질문지법과 관찰법을 이용하였다. 문헌고찰과 전문가집단의 검토를 통해 측정 및 관찰, 모니터, 산소공급, 영양, 배설 및 배액, 기동성, 위생, 안전, 체온유지, 수술전 준비, 검사물 채취, 각종 처치의 준비 및 간호, 피부 및 상처간호, 감염관리, 투약, 상담 및 교육, 임종간호, 기록 확인, 환자 인수인계, 물품관리, 시설물관리, 환경관리, 의사소통, 교육, 의사처방 확인, 전달업무, 평가, 전문직 개발의 총 28개 영역의 254개 간호활동이 결정되었다. 2. 2002년 4월 12일부터 2002년 4월 17일까지 서울시내와 경기도내 종합병원의 심장외과 중환자실 2개 기관에서 간호사 22명을 대상으로 심장외과 중환자실 간호활동조사지를 이용하여 간호활동의 수행도를 분석하였다. 4일동안 연구자 2인이 간호사 12명을 대상으로 직접관찰법을 이용하여 간호활동의 수행 빈도와 새로운 간호활동을 추출하였다. 결정된 항목을 기반으로 간호활동별 수행도와 수행 빈도를 조사한 결과 28개 업무범주 중에서 모니터 641회(19.5%), 측정 및 관찰이 554회(16.8%), 기록 확인 527회(16.0%) 순으로 관찰되었다. 254개의 간호활동에 24개 간호활동이 직접관찰법에 의해 새롭게 추출되었다. 그 결과 278개의 간호활동은 전문가에 의해 검토되어 총 264개의 간호활동과 22개의 업무범주로 수정되었다. 3. 질문지법과 관찰법을 통해 추출한 심장외과 중환자실 예비 간호활동을 전문가 집단 총 25인의 내용타당도를 검증한 후 최종 심장외과 중환자실 간호업무 내용의 틀을 확정하였다. 내용타당도를 통해 작성된 최종 심장외과 중환자실 간호업무의 틀은 사정, 감시, 호 흡관리, 영양관리, 배설 및 배액 관리, 기동성관리, 위생관리, 안전관리, 체온관리, 검사물 채취, 각종 처치의 준비 및 보조, 피부 및 상처 관리, 감염관리, 투약관리, 교육 및 지지, 임종간호, 기록 및 보관, 물품관리, 환경관리, 의사소통, 평가, 전문직개발의 22개 업무범주의 총 231개 간호활동으로 작성되었다. 심장외과 중환자실에서 근무하는 간호사의 간호업무는 의료진의 효율적인 관리를 위해서 명확히 규정되어야만 한다. 본 연구에서는 심장외과 중환자실 일반간호사의 업무로서 부적절하고 타당하지 않은 몇 가지의 간호활동이 발견되었다. 심장외과 중환자실 일반 간호 사에 대한 정확하고 명확한 업무규정은 동료의료진간의 역할 갈등을 감소시키고 간호활동의 효율성을 증가시키는데 기여할 것이다. 결과적으로, 심장외과 중환자실 간호사와 환자의 만족도를 향상시킬 것이다. [영문] This study was conducted to provide for a basic resource, which can be used to set up a efficient management system in Cardiac Surgery Intensive Care Units(CSICU). This rational system offers standards and a framework for nursing activities at CSICU. The study investigated and analyzed the nursing care activities of typical nurses employed in two general hospitals located in Seoul and the Kyonggi Province. The detailed ways of analyses and their findings are follows: 1. Questionnaires were administered and observation methods were used, to examine the nursing activities performed in the CSICU after having reviewed related literatures and a review by the experts. Thus, the nursing activities were designating 254 activities and classified into 28 categories under those nursing activities. These 28 categories of the nursing activities are measurements observation, monitoring, oxygen supply, nutrition, elimination drainage, sanitation, safety, temperature maintenance, surgery preparation, specimens collection, setting up and care of treatment, skin wound management, infection management, administration of medication, consultation/education, dying patient care, confirming of recordings, taking-over of patient, supplies management, facilities management, environment management, communications, education, confirming of doctor''s prescriptions, delivering tasks, evaluation, and professional development. 2. The 22 nurses in the 2 CSICUs filled out questionnaires about nursing activities from 12 April, 2002 to 17 April, 2002. The frequency of the nursing activities in the 28 categories counted and new nursing activities added by directly observing 12 nurses by two trained research staffs for 4 day. Out of the 28 categories, 641 monitoring (19.5%), 554 measurements observation (16.8%) and 527 confirming of recordings (16.0%) were observed. In addition to the 28 categories of the nursing activities, 24 nursing activities were newly selected by the direct observation and added to the existing 254 nursing activities. The resulting, 278 nursing activities, were examined by the experts and validated by the degree of agreement on their validity among the experts. Experts could adjust the 278 nursing activities to a total of the 264 nursing activities. And 28 categories were adjusted 22 categories by the experts. 3. In terms of validity, the 264 nursing activities were analysed by the 25 experts. As a result, 231 nursing activities were found valid and remained as appropriate nursing activities to be used for the careful analysis of the nursing activities in CSICUs. The 22 categories are as below: assessment, monitoring, respiration management, nutrition management, elimination drainage management, mobility management, sanitation management, safety management, temperature management, specimens collection, preparation and assistance of treatment, skin wound management, infection management, medication management, education support, dying patient care, recording keeping, supplies management, environment management, communications, evaluations, professional development. Nursing activities by nurses working in CSICU need to be clearly defined for an effective management of the medical staffs. In this study, we found some nursing activities invalid and inappropriate as the works of the staff nurse. The manifest job description of the staff nurse will contribute to improving the efficiency of the nursing activities and to reducing the role conflicts among the medical staffs. Eventually, it will heighten the satisfaction of patients as well as nurses in the CSICU.ope

망간 산화물 나노 촉매의 표면 기능화를 통한 전자구조 제어 연구

학위논문 (석사)-- 서울대학교 대학원 : 재료공학부, 2016. 2. 남기태.Nature has selected various types of manganese enzymes due to good catalytic activity resulting from highly redox-active characteristics of manganese. In the meanwhile, multinuclear manganese enzymes are known to mediate reactions with high performance by the cooperative effects of each manganese ion in the structure. Interestingly, in this regards, photosynthetic water oxidase which has a tetranuclear Mn4CaO5 cluster in PS II is known to be the best catalyst for water oxidation among all reported. Inspired by this Mn-Ca cluster in nature, the Calcium EDTA chelates were functionalized on the manganese oxide nanoparticlesso to change the electronic structure of manganese and broaden the applicability of catalyst as a future work. In this work, the removal of myristic acid, the original ligand of manganese oxide nanoparticles, and successful ligand exchange to Ca-EDTA chelates were verified by the FT-IR spectroscopy. Moreover, the local structure on the surface of manganese oxide nanoparticles was suggested by the stretching vibration of COO- and bending vibration of C-N bondcalcium ion and manganese ion are proposed to form pseudo-bridge as a major state and the nitrogen atoms are suggested to chelate the manganese ion on the surface of manganese oxide nanoparticles. Partially, some carboxylate groups of EDTA are considered to be bound as unidentate and bidentate mode as a mixture. Also, electronic structural analysis of calcium EDTA chelated manganese oxide nanoparticles was performed by EPR analysis. The calcium-affected manganese ions are verified to have high axial zero-field-splitting (D ~ 0.023 cm^-1) compared to conventional Mn (II) (D = 0.014 cm^-1) by a multi-frequency EPR simulation and are demonstrated to have weak exchange coupling between manganese ions (J below 1 cm^-1) via temperature dependency analysis of EPR and SQUID. The observation of electronic structural change of manganese, the axial distortion in the ligand field of manganese and weak exchange coupling between manganese ions, in this work will be a pioneering model in heterogeneous system for further application to catalysis and in the meantime for better understanding of the role of calcium ion in Mn-Ca cluster in nature.Chapter 1 Introduction 1 1.1 Mn Based Natural Enzymes 1 1.2 Homogeneous Mn Based Synthetic Catalysts 7 1.3 Effects of Redox-inactive Metals on Catalysis 9 1.4 Importance of Hetero-Hybrid Catalytic Materials 15 1.5 Research Scope and Materials Design 18 Chapter 2 Experimental and Procedure 22 2.1 Surface Functionalization of Manganese Oxide NPs 22 2.1.1 Synthesis of Manganese (II) Oxide Nanoparticles 22 2.1.2 Surface Functionalization via Ligand Exchange 23 2.1.3 Decoration of Calcium ion 24 2.2 Characterization of Surface - Functionalized Manganese Oxide Nanoparticles 24 2.2.1 Powder X-ray Diffraction (XRD) 24 2.2.2 Scanning Electron Microscopy (SEM) 24 2.2.3 Transmission Electron Microscopy (TEM) 25 2.2.4 X-ray Absorption Spectroscopy (XAS) 25 2.2.5 Fourier Transform Infrared Spectroscopy (FT-IR) 26 2.2.6 Cyclic Voltammetry (CV) 26 2.2.7 Multi-frequency Electron Paramagnetic Resonance (EPR) 27 2.2.8 Superconducting Quantum Interference Device (SQUID) 27 Chapter 3 Results and Discussion 28 3.1 Characterization of Structure 28 3.1.1 Morphological Analysis 28 3.1.2 Phase Analysis 32 3.1.3 Local Structure Analysis 38 3.2 Characterization of Electronic Structure 56 3.2.1 Multi-frequency EPR 56 3.2.2 Non-Curie Behavior (Magnetic Coupling Effect) 61 3.2.3 Simulation of EPR Signal 66 Chapter 4 Effects of Redox-inactive Metals on Surface-Functionalized Mn Oxide NPs 71 4.1 Electronic Structural Change in Mn Oxide NPs 71 4.2 Change of Redox Property in Mn Oxide NPs 74 Chapter 5 Conclusion 76 References 78 국문 초록 87Maste

Identification of factors related to nurses' individual performance using a multilevel analysis

간호학과/박사[한글]본 연구는 간호사의 개인성과를 향상시키는 정책적 접근 전략을 모색하기 위해 개인성과에 미치는 영향을 개인수준의 특성과 간호단위인 집단수준의 특성을 모두 고려하여 다수준 분석(multilevel analysis)을 적용한 횡단적 조사연구이다. 본 연구 자료는 2006년 2월 20일부터 3월 20일까지 서울 및 6대 광역시와 전국 7개 도의 총 28개 병원의 182개의 간호단위에 속한 1966명의 간호사를 집락표집(cluster sampling)하여 수집하였다. 본 연구에서 수집된 자료는 SAS 8.2를 이용하여 기술통계방법, Cronbach's α 계수, 상관분석(correlation analysis), Varimax rotation에 의한 주성분분석, 다수준 분석(multilevel analysis)을 이용하여 분석하였다.본 연구의 결과에 따르면, 간호사가 지각하는 간호업무성과와 관련된 개인수준 변수는 직위, 총근무경력, 고용형태, 자기효능감, 긍정적 감정성향, 부정적 감정성향, 상사의 지지, 동료의 지지이며, 집단수준 변수로는 간호단위 집담회 횟수로 나타났다.간호사가 지각하는 조직시민행동과 관련된 개인수준 변수는 직위, 총근무경력, 자기효능감, 긍정적 감정성향, 부정적 감정성향, 상사의 지지이며, 집단수준 변수로는 집단응집력, 간호단위 월평균 급여수준이 통계적으로 유의하게 나타났다. 또한 조직시민행동에 영향을 주는 변수로서 집단효능감이 유의하게 나타났다. 간호사가 지각하는 집단응집력의 회귀계수가 집단별로 무선적으로 변화하였고, 집단응집력이 간호업무성과에 미치는 영향에 있어 집단간 차이가 나타났다. 간호사의 간호업무성과와 조직시민행동의 간호사 개인수준 분산에 대한 개인수준 예측변수들의 설명력은 각각 41.5%, 31.7%로 나타났다. 간호사의 간호업무성과와 조직시민행동의 집단수준 분산에 대한 집단수준 예측변수들의 설명력은 각각 89.7%, 80.9%로 나타났다.이와 같은 결과는 개인성과를 설명하는데 있어 기존의 연구에서는 개인적 수준의 오차변량만을 제시하였지만, 본 연구의 다수준 분석을 통하여 개인적 수준과 집단적 수준의 오차변량을 제시하여 개인과 집단수준의 변수를 통하여 분산의 변화를 확인하였다. 즉, 집단수준의 변수가 오차변량을 줄여줌을 보여 주었으며, 집단수준의 변수가 개인수준의 분산과 집단수준의 분산에 모두 영향을 주어, 집단수준의 변수가 개인성과에 영향을 미침을 확인하였다.결론적으로 집단의 요인이 우리나라 병원간호사의 개인성과에 미치는 영향을 알아보기 위해 시행된 본 연구를 통해서 간호사의 개인성과에는 차이가 존재하며 여기에는 간호사 개인적 요인 이외에 집단의 요인인 집단응집력이 작용함을 알 수 있었다. 따라서 간호 조직성과를 향상시키기 위한 정책적 접근은 기존의 개인에 대한 교육이나 훈련뿐만 아니라, 집단응집력과 집단효능감과 같은 상위수준의 조직요인에 대한 정책적 접근이 필요함을 시사한다고 하겠다. [영문]The main purpose of this study was to identify factors related to nurses' individual performance using multilevel analysis which consider both characteristics in individual and nurses' groups. And the results of the study can help to suggest strategies to improve nurses' individual performance.The data was collected from 1,996 nurses using self-administered questionnaires between February, 20th and March, 20th 2006. Using the cluster sampling method, 182 nursing units in 28 hospitals from various regions such as Seoul, six metropolitan city, and seven provinces were selected. The data was analyzed by SAS 8.2 using descriptive statistics, Cronbach's α coefficient, correlation analysis, principal component method with Varimax rotation and multilevel analysis.The results of the study indicated that individual level variables related to nursing performance, were job position, total years of experience, employment status, self-efficacy, positive affectivity, negative affectivity, supervisor support, and peer support. The group level variables were the number of conferences in a nursing unit. The individual level variables related to organizational citizenship behavior, were job position, the total years of experience, self-efficacy, positive affectivity, negative affectivity, and supervisor support. The group level variables were group cohesion and the average salary level of a nursing unit. The effective variable which affects organizational citizenship behavior was collective efficacy.The regression coefficient of group cohesion perceived by nurses was randomly changing between groups, and group cohesion had influenced differently on nursing performance between groups.The explanatory powers of individual level variables, which is related to individual level variances of nursing performance and organizational citizenship behavior were 41.5% and 31.7%, respectively. The explanatory powers of group level variables, which is related to group level variances of nursing performance and organizational citizenship behavior was 89.7% and 80.9%, respectively.The previous researches had limitations considering error variance on only individual levels, but this study considered error variances in group levels as well as individual levels using multilevel analysis. This study showed changing variances through variables in individual and group levels.In other words, this study showed that group level variables reduced error variances, and variables in group levels have influences on variances in both individual levels and group levels. Therefore, the high explanatory power of group level variables implies that hospital managers should consider group level variables to improve nurses' performance.In conclusion, this research showed that there were differences in individual performances between nurses and the differences came from group level factors such as group cohesion as well as individual level factors. It is necessary to consider not only individual factors but also higher-level organizational factors such as group cohesion and collective efficacy to improve nurses‘ individual performance.ope

Up-regulation of acetyl-CoA carboxylase α and fatty acid synthase by human epidermal growth factor receptor 2 at the translational level in breast cancer cells

Expression of the HER2 oncogene is increased in ∼30% of human breast carcinomas and is closely correlated with the expression of fatty acid synthase (FASN). In the present study, we determined the mechanism by which FASN and acetyl-CoA carboxylase α (ACCα) could be induced by HER2 overexpression. SK-BR-3 and BT-474 cells, breast cancer cells that overexpress HER2, expressed higher levels of FASN and ACCα compared with MCF-7 and MDA-MB-231 breast cancer cells in which HER2 expression is low. The induction of FASN and ACCα in BT474 cells were not mediated by the activation of SREBP-1. Exogenous HER2 expression in MDA-MB-231 cells induced the expression of FASN and ACCα, and the HER2-mediated increase in ACCα and FASN was inhibited by both LY294002, a phosphatidylinositol 3-kinase inhibitor, and rapamycin, a mammalian target of rapamycin (mTOR) inhibitor. In addition, the activation of mTOR by the overexpression of RHEB in MDA-MB-231 cells increased the synthetic rates of both FASN and ACCα. On the other hand, FASN and ACCα were reduced in BT-474 cells by a blockade of the mTOR signaling pathway. These changes observed in their protein levels were not accompanied by changes in their mRNA levels. The 5′- and 3′-untranslated regions of both FASN and ACCα mRNAs were involved in selective translational induction that was mediated by mTOR signal transduction. These results strongly suggest that the major mechanism of HER2-mediated induction of FASN and ACCα in the breast cancer cells used in this study is translational regulation primarily through the mTOR signaling pathway.ope