• 제목/요약/키워드: Observational period

검색결과 262건 처리시간 0.028초

CSR Impact on the Firm Market Value: Evidence from Tour and Travel Companies Listed on Chinese Stock Markets

  • LEE, Jung Wan
    • The Journal of Asian Finance, Economics and Business
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    • 제7권7호
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    • pp.159-167
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    • 2020
  • The study examines the impact of corporate social responsibility (CSR) activity on the firm market value, in particular, market capitalization of tour operators listed on Chinese stock markets. This study employs panel data analysis methods to examine endogeneity concerns in observational data. The balanced panel data includes a total of 1,296 observations with 27 cross-sections of tour operators listed on Chinese stock markets and with 48 time-specific periods from March 2006 to December 2017. The results indicate that CSR activity has a negative impact on the market value of the firm for the concurrent period, but from one-period time lag and afterwards CSR activity has a strong positive impact on the market value and sustains its positive impact on the market value even for a two-period time lag. The findings suggest that the economic effect of CSR activity on the firm market value tends to take some degree of lagged effects to be fully showcased in the market capitalization of tour operators and travel companies listed on Chinese stock markets. The findings suggest that, though CSR activity may carry some financial risk for an immediate short-term, tour operators must put a lot of time and effort into making CSR actions effective.

Reconstruction of Terrestrial Water Storage of GRACE/GFO Using Convolutional Neural Network and Climate Data

  • Jeon, Woohyu;Kim, Jae-Seung;Seo, Ki-Weon
    • 한국지구과학회지
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    • 제42권4호
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    • pp.445-458
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    • 2021
  • Gravity Recovery and Climate Experiment (GRACE) gravimeter satellites observed the Earth gravity field with unprecedented accuracy since 2002. After the termination of GRACE mission, GRACE Follow-on (GFO) satellites successively observe global gravity field, but there is missing period between GRACE and GFO about one year. Many previous studies estimated terrestrial water storage (TWS) changes using hydrological models, vertical displacements from global navigation satellite system observations, altimetry, and satellite laser ranging for a continuity of GRACE and GFO data. Recently, in order to predict TWS changes, various machine learning methods are developed such as artificial neural network and multi-linear regression. Previous studies used hydrological and climate data simultaneously as input data of the learning process. Further, they excluded linear trends in input data and GRACE/GFO data because the trend components obtained from GRACE/GFO data were assumed to be the same for other periods. However, hydrological models include high uncertainties, and observational period of GRACE/GFO is not long enough to estimate reliable TWS trends. In this study, we used convolutional neural networks (CNN) method incorporating only climate data set (temperature, evaporation, and precipitation) to predict TWS variations in the missing period of GRACE/GFO. We also make CNN model learn the linear trend of GRACE/GFO data. In most river basins considered in this study, our CNN model successfully predicts seasonal and long-term variations of TWS change.

Absolute calibration of near-infrared Period-Luminosity-Metallicity relations for RR Lyrae variables using Gaia EDR3

  • Bhardwaj, Anupam;Rejkuba, Marina;Yang, Soung-Chul
    • 천문학회보
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    • 제46권1호
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    • pp.35.1-35.1
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    • 2021
  • RR Lyrae stars are sensitive probe for the precision stellar astrophysics and also for the cosmic distance scale thanks to their well-defined near-infrared Period-Luminosity relations (PLRs). These horizontal branch variables can be used for primary calibration of the first-rung of population II distance ladder providing an evaluation of the ongoing tension between Cepheid-Supernovae based Hubble constant and the Planck results. Therefore, absolute calibration of RR Lyrae PLRs is now crucial to complement or test the tip of the red giant branch based distances, and in turn, population II star based Hubble constant measurements. While the pulsation models of RR Lyrae can reproduce most observables, they predict a significant metallicity effect on their JHKs-band PLRs that is inconsistent with so-far limited observational studies. We remedy this inconsistency of metallicity dependence in RR Lyrae PLRs by combining their near-infrared observations in the globular clusters of different mean-metallicities with the new parallaxes from the Gaia early data release 3 (EDR3). Our empirical results on Period-Luminosity-Metallicity (PLZ)relations are consistent with theoretical predictions but the precision of absolute calibrations is still affected by the parallax uncertainties and the systematic zero-point offset present in the Gaia EDR3.

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The control of invasive Candida infection in very low birth weight infants by reduction in the use of 3rd generation cephalosporin

  • Chang, Yu Jin;Choi, Il Rak;Shin, Won Sub;Lee, Jang Hoon;Kim, Yun Kyung;Park, Moon Sung
    • Clinical and Experimental Pediatrics
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    • 제56권2호
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    • pp.68-74
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    • 2013
  • Purpose: To evaluate the effectiveness of new management policies on the incidence of invasive Candida infections Methods: This observational study involved a retrospective analysis of the patients' medical records. In total, 99 very low birth weight infants, who were admitted to the neonatal intensive care unit at Ajou University Hospital from January 2010 to December 2011, were enrolled for the study. Period I, defined as the period before the revision of management policies, comprised 57 infants; whereas, period II, defined as the period after the implementation of new management policies, comprised 42 infants. The new management policies entailed a reduction in antibiotic and histamine type 2 receptor blocker (H2 blocker) use, duration of central venous catheterization, and duration of endotracheal intubation. Results: There was a significant overall decrease in the use of antibiotics including 3rd generation cephalosporin and H2 blockers (P<0.05), and a significantly lower incidence of invasive Candida infections in period II as compared to period I (0/42 vs. 6/57, respectively; P=0.037). Comparison between infants with invasive Candida infections (n=6) and those without (n=93) showed that gestational age (odds ratio [OR], 0.909; 95% confidence interval [CI], 0.829 to 0.996; P=0.042) and the duration of 3rd generation cephalosporin use (OR, 1.093; 95% CI, 1.009 to 1.183; P=0.029) were statistically significant risk factors. Conclusion: The new management policies effectively decreased overall use of antibiotics, especially 3rd generation cephalosporin, and H2 blockers, which led to a significantly lower incidence of invasive Candida infections.

COVID-19 발현 이후 병원간 이송 시 민간 이송업체를 통해 응급실로 전원된 환자들의 특성 변화 : 후향적 연구 (Changes in the characteristics of patients transferred to the emergency room through private institutions during inter-hospital transport after the COVID-19 outbreak : A retrospective study)

  • 김성주;지재구;장윤덕;이시원;유재광;강지훈
    • 한국응급구조학회지
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    • 제25권1호
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    • pp.125-134
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    • 2021
  • Purpose: The purposes of this study were to determine the changes in the pattern of patients who were transferred to the emergency room through inter-hospital private institutions and to determine how long transport takes following the COVID-19 outbreak. Methods: This retrospective observational study analyzed the emergency medical services reports of private institutions following the COVID-19 outbreak in South Korea. The study was conducted in Busan between January 19, 2019 and January 18, 2020, and between January 19, 2020 and January 18, 2021. Results: Upon comparing the patient transport times during the "Pre-COVID-19 period" and "COVID-19 period," a significant delay was noticed in the preparation for transfer of patients during the "COVID-19 period" (p<.05). There were significantly more patients with respiratory infections and patients who complained of general symptoms during the "COVID-19 period." Moreover, there was a higher frequency of patients who were transferred to a 'Level I' emergency room during the "COVID-19 period" compared to during the "Pre-COVID-19 period" (p<.05). Conclusion: Following the COVID-19 outbreak, there is a delay in patient transport to the emergency room through private institution inter-hospital transport and an increase in the number of patients complaining of respiratory infection symptoms. Thus, emergency medical services need additional administrative and economic support to transport infected patients.

Clinical Characteristics of Acute Drug Intoxication in Emergency Department

  • Kim In Byung;Chun Sung Pil;Kim Seung Whan
    • 대한의생명과학회지
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    • 제10권3호
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    • pp.299-303
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    • 2004
  • The number of acute drug intoxication who visiting to emergency department which is located near urban and rural area concomitantly is inclined to increase slightly, The purpose of this study was the investigation of methods and strategies of management of acute drug intoxication in emergency department Clinical trials were done on 92 cases of acute drug intoxication visiting to Emergency Department of Chungnam National University Hospital during 4 months from April to July 2003. 1. The total number of acute drug intoxication during this period was 92 patients, which presented 0.95% of all the emergency department visiting patients during the study. The intentional ingestions were observed in 84 cases (91.3%). 2. The maximal point of age distribution was 4th decade. The number of that was 21 cases (22.8%). 3. The number of patients who had ingested benzodiazepines and doxylamine succinates was 26 cases (28.2%), organophosphorus was 20 (21.7%), paraquat was 10 (10.8%), others were 36 (39.3%). 4. Five kinds of po1ydrug ingestion was observed in 3 cases, four kinds was observed in 3, three kinds was observed in 5 and co-ingestion of alcohol was observed in 28 cases (30.4%). 5. The mortality was occurred in 4 cases, 2 of them were caused by paraquat, 1 of them was caused by organophosphorus (OP), 1 of them was caused by acetic acid. 6. The gastric larvage as a mean of treatment modality was done in 57 cases (61.9%). The use of activated charcoal was done in 8 (8.69%). The maintenance of tracheal intubation was done in 6 (6.52%). 7. The mean observational period in emergency department was 8 hours 42 minutes in benzodiazepine and doxylamine succinate group, 21 hours 46 minutes in OP, 20 hours 39 minutes in other germicidal except OP, 23 hours 9 minutes in paraquat group. Without a drug information and intoxication center in Korea, We should minimize the exhaustion of medical resources by establishment of determinant criteria which can be seen in relatively less-complicated cases of acute drug intoxication. Thus, we should consider the introduction of simple toxicology treatment protocol and toxicologic observation unit in emergency department as possible means to reduce economical and social burdens.

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Influence of Foreign Culture and Hybrid Culture: The Case of Kandyan Kingdom of Sri Lanka

  • Ranathunga, Gayathri Madubhani
    • International Journal of Costume and Fashion
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    • 제13권2호
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    • pp.53-64
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    • 2013
  • Culture has played a pivotal role in fashion from time immemorial. The objective of this research is to explore the power of cultural affiliation in fashion. The selected study setting is the Kandyan Kingdom of Sri Lanka. The Kandyan Kingdom of Sri Lanka lasted almost 3 1/2 centuries from 1474-1815. The whole period faced different foreign cultural forces. As a result of such diverse cultural influences the Kandyan dress showed a hybrid formation of Western and South Indian and Sinhalese traditional sartorial features. Sewing techniques and unsewn dress arrangement methods were mixed together. The dress became an amazing blend of Eastern and Western dress items. They combined different aspects of foreign dress together to yield a unique result. The analysis comprises observational study of actual descriptions made by observer- participants, historical records, murals of the period review of ancient literature and research papers relevant to the subject. Reliability of the data was ensured. The pictorial data were cross checked from different literary sources. Many original sources were used. Results: Culture and fashion have strong interconnection. When features of culture change, trends of fashion are gradually correspondingly changed.

손위생 수행률에 대한 호손효과 (The Hawthorne Effect on the Adherence to Hand Hygiene)

  • 송주연;정인숙
    • Perspectives in Nursing Science
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    • 제12권1호
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    • pp.7-13
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    • 2015
  • Purpose: This observational study was aimed to determine the influence of the Hawthorne effect on the adherence to hand hygiene (HH) among healthcare workers (HCWs) in South Korea. Methods: HCWs were monitored in 2 periods regarding adherence to HH when there were indications for HH. In first period, HCWs recognized that their behavior of hand hygiene being observed (overt observation), and did not recognize in second period (covert observation). Results: The overall difference in HH rate between two periods was 45.0% point (77.8% vs 32.8%). There were significant differences between profession but in nurse aids. The differences in HH rate between two periods were 46.1% point in nurses, 29.9% point in physicians, 64.0% in radiologists, 62.5% point in laboratory technicians, 36.4% point in physio-therapist, and 1.0% point in nurse aids. The Hawthorne effect on the adherence to HH lasted more than 3 months. Conclusion: The Hawthorne effect markedly influence on the adherence to HH regardless of profession except nurse aids. Therefore, Hawthorne effect can be useful tool to improve and sustain the adherence to HH among HCWs in South Korea.

A SIMPLE DISK-HALO MODEL FOR THE CHEMICAL EVOLUTION OF OUR GALAXY

  • Lee, S.W.;Ann, H.B.
    • 천문학회지
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    • 제14권2호
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    • pp.55-71
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    • 1981
  • On the basis of observational constraints, particularly the relationship between metal abundance and cumulative stellar mass, a simple two-zone disk-halo model for the chemical evolution of our Galaxy was investigated, assuming different chemical processes in the disk and halo and the infall rates of the halo gas defined by the halo evolution. The main results of the present model calculations are: (i) The halo formation requires more than 80% of the initial galactic mass and it takes a period of $2{\sim}3{\times}10^9$ yrs. (ii) The halo evolution is divided into two phases, a fast collapse phase ($t=2{\sim}3{\times}10^8$ yrs) during which period most of the halo stars $({\sim}95%)$ are formed and a later slow collapse phase which is characterized by the chemical enrichment due to the inflow of external matter to the halo. (iii) The disk evolution is also divided into two phases, an active disk formation phase with a time-dependent initial mass function (IMF) up to $t{\approx}6{\times}10^9$ yrs and a later steady slow formation phase with a constant IMF. It is found that at the very early time $t{\approx}5{\times}10^8$ yrs, the metal abundance in the disk is rapidly increased to ${\sim}1/3$ of the present value but the total stellar mass only to ${\sim}10%$ of the present value, finally reaching about 80% of the present values toward the end of the active formation phase.

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기상청 지구시스템모델에서의 구름입자 수농도 모수화 방법 개선 (Improvement of Cloud Physics Parameterization in the KMA Earth System Model)

  • 이한아;염성수;심성보;부경온;조천호
    • 대기
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    • 제24권1호
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    • pp.111-122
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    • 2014
  • In the Korea Meteorological Administration earth system model (HadGEM2-AO), cloud drop number concentration is determined from aerosol number concentration according to the observed relationship between aerosol and cloud drop number concentrations. However, the observational dataset used for establishing the relationship was obtained from limited regions of the earth and therefore may not be representative of the entire earth. Here we reestablished the relationship between aerosol and cloud drop number concentrations based on a composite of observational dataset obtained from many different regions around the world that includes the original dataset. The new relationship tends to provide lower cloud drop number concentration for aerosol number concentration < 600 $cm^{-3}$ and the opposite for > 600 $cm^{-3}$. This new empirical relationship was applied to the KMA earth system model and the historical run (1861~2005) is made again. Here only the 30 year (1861~1890) averages from the runs with the new and the original relationships between aerosol and cloud drop number concentrations (newHIST and HIST, respectively) were compared. For this early period aerosol number concentrations were generally lower than 600 $cm^{-3}$ and therefore cloud drop number concentrations were generally lower but cloud drop effective radii were larger for newHIST than for HIST. The results from the complete historical run with the new relationship are expected to show more significant differences from the original historical run.