• Title/Summary/Keyword: bias effect

Search Result 1,482, Processing Time 0.039 seconds

Effects of CO2 and Climate on water use efficiency and their linkage with the climate change

  • Umair, Muhammad;Kim, Daeun;Choi, Minha
    • Proceedings of the Korea Water Resources Association Conference
    • /
    • 2019.05a
    • /
    • pp.149-149
    • /
    • 2019
  • Gross Primary production (GPP) and evapotranspiration (ET) are the two critical components of carbon and water cycle respectively, linking the terrestrial surface and ecosystem with the atmosphere. The ratio between GPP to ET is called ecosystem water use efficiency (EWUE) and its quantification at the forest site helps to understand the impact of climate change due to large scale anthropogenic activities such as deforestation and irrigation. This study was conducted at the FLUXNET forest site CN-Qia (2003-2005) using Community land model (CLM 5.0). We simulated carbon and water fluxes including GPP, ecosystem respiration (ER), and ET using climatic variables as forcing dataset for 30 years (1981-2010). Model results were validated with the FLUXNET tower observations. The correlation showed better performance with values of 0.65, 0.77, and 0.63 for GPP, ER, and ET, respectively. The model underestimated the results with minimum bias of -0.04, -1.67, and -0.40 for GPP, ER, and ET, respectively. Effect of climate 'CLIM' and '$CO_2$' were analyzed based on EWUE and its trend was evaluated in the study period. The positive trend of EWUE was observed in the whole period from 1981-2010, and the trend showed further increase when simulated with rising $CO_2$. The time period were divided into two parts, from 1981-2000 and from 2001 to 2010, to identify the warming effect on EWUE. The first period showed the similar increasing trend of EWUE, but the second period showed slightly decreasing trend. This might be associated with the increase in ET in the wet temperate forest site due to increase in climate warming. Water use efficiency defined by transpiration (TR) (TWUE), and inherent-TR based WUE (IT-WUE) were also discussed. This research provides the evidence to climate warming and emphasized the importance of long term planning for management of water resources and evaporative demand in irrigation, deforestation and other anthropogenic activities.

  • PDF

Different approaches for numerical modeling of seismic soil-structure interaction: impacts on the seismic response of a simplified reinforced concrete integral bridge

  • Dhar, Sreya;Ozcebe, Ali Guney;Dasgupta, Kaustubh;Petrini, Lorenza;Paolucci, Roberto
    • Earthquakes and Structures
    • /
    • v.17 no.4
    • /
    • pp.373-385
    • /
    • 2019
  • In this article, different frequently adopted modeling aspects of linear and nonlinear dynamic soil-structure interaction (SSI) are studied on a pile-supported integral abutment bridge structure using the open-source platform OpenSees (McKenna et al. 2000, Mazzoni et al. 2007, McKenna and Fenves 2008) for a 2D domain. Analyzed approaches are as follows: (i) free field input at the base of fixed base bridge; (ii) SSI input at the base of fixed base bridge; (iii) SSI model with two dimensional quadrilateral soil elements interacting with bridge and incident input motion propagating upwards at model bottom boundary (with and without considering the effect of abutment backfill response); (iv) simplified SSI model by idealizing the interaction between structural and soil elements through nonlinear springs (with and without considering the effect of abutment backfill response). Salient conclusions of this paper include: (i) free-field motions may differ significantly from those computed at the base of the bridge foundations, thus put a significant bias on the inertial component of SSI; (ii) conventional modeling of SSI through series of soil springs and dashpot system seems to stay on the safer side under dynamic conditions when one considers the seismic actions on the structure by considering a fully coupled SSI model; (iii) consideration of abutment-backfill in the SSI model positively affects the general response of the bridge, as a result of large passive resistance that may develop behind the abutments.

Efficacy and Safety of the Antidiabetic effect of Hwangryunhaedok-tang for Type 2 Diabetes Mellitus Patients without Complications: A Systematic Review and Meta-Analysis (합병증을 동반하지 않은 2형 당뇨병 환자에 대한 황련해독탕의 혈당 강하 효과에 대한 유효성과 안전성 : 체계적 문헌 고찰과 메타분석)

  • Baek, Ji-soo;Shin, Seon-mi;Shin, Dong-guk;Cho, Chung-sik
    • The Journal of Internal Korean Medicine
    • /
    • v.42 no.4
    • /
    • pp.605-621
    • /
    • 2021
  • Objectives: The purpose of this review is to assess the efficacy and safety of Hwangryunhaedok-tang for type 2 diabetes without complications by systemic review and meta-analysis of randomized controlled trials (RCTs). Methods: We searched the following up to March 31. 2021: PubMed, EMBASE, The Cochrane Library, CNKI, CiNii, KISS, KMBASE, OASIS, ScienceON. Data extraction and assessment of Cochrane's risk of bias (RoB) tool were performed by two independent authors, and if there was disagreement between two researchers, it was resolved through the intervention of a third researcher. Results: A total of seven trials are included in this systemic review. The treatment group (Hwangryunhaedok-tang plus conventional treatment) showed more statistically significant effects than did the control group (conventional treatment only) in fasting plasma glucose level, 2-hour postprandial plasma glucose level, glycated hemoglobin A1c, fasting insulin level, and HOMA-IR. There was no significant difference between the treatment group (Hwangryunhaedok-tang alone) and the control group (metformin alone). Conclusion: Hwangryunhaedok-tang might have efficacy and safety in controlling blood sugar level and improving insulin-resistance. However, the number of studies included in the meta-analysis was insufficient, and the Hwangryunhaedok-tang used in the included studies was not standardized. Also, the quality of the involved studies was generally low. Therefore, further studies are needed to determine the efficacy and safety of Hwangryunhaedok-tang treatment for type 2 diabetes mellitus.

Basic reproduction number of African swine fever in wild boars (Sus scrofa) and its spatiotemporal heterogeneity in South Korea

  • Lim, Jun-Sik;Kim, Eutteum;Ryu, Pan-Dong;Pak, Son-Il
    • Journal of Veterinary Science
    • /
    • v.22 no.5
    • /
    • pp.71.1-71.12
    • /
    • 2021
  • Background: African swine fever (ASF) is a hemorrhagic fever occurring in wild boars (Sus scrofa) and domestic pigs. The epidemic situation of ASF in South Korean wild boars has increased the risk of ASF in domestic pig farms. Although basic reproduction number (R0) can be applied for control policies, it is challenging to estimate the R0 for ASF in wild boars due to surveillance bias, lack of wild boar population data, and the effect of ASF-positive wild boar carcass on disease dynamics. Objectives: This study was undertaken to estimate the R0 of ASF in wild boars in South Korea, and subsequently analyze the spatiotemporal heterogeneity. Methods: We detected the local transmission clusters using the spatiotemporal clustering algorithm, which was modified to incorporate the effect of ASF-positive wild boar carcass. With the assumption of exponential growth, R0 was estimated for each cluster. The temporal change of the estimates and its association with the habitat suitability of wild boar were analyzed. Results: Totally, 22 local transmission clusters were detected, showing seasonal patterns occurring in winter and spring. Mean value of R0 of each cluster was 1.54. The estimates showed a temporal increasing trend and positive association with habitat suitability of wild boar. Conclusions: The disease dynamics among wild boars seems to have worsened over time. Thus, in areas with a high elevation and suitable for wild boars, practical methods need to be contrived to ratify the control policies for wild boars.

Effect of Herbal Medicine on Hepatitis C: a Systematic Review and Meta-analysis (C형간염에 대한 한약의 치료효과 : 체계적 문헌고찰과 메타분석)

  • Kang, Eun-jin;Kim, Kyong-lim;Kim, Kyoung-min
    • The Journal of Internal Korean Medicine
    • /
    • v.40 no.3
    • /
    • pp.312-330
    • /
    • 2019
  • Objectives: The present study aimed to provide clinical evidence on the effect of herbal medicine on the treatment of hepatitis C using a systematic review and meta-analysis of randomized controlled trials (RCTs). Methods: This study included RCTs that verified the effects of herbal medicine for the treatment of hepatitis C. A literature search of English, Chinese, and Korean databases was performed, and the selected literature was assessed to investigate the risk of bias. Results: The analysis included 14 RCTs. The total effective rate was the most commonly used outcome measure. The meta-analysis revealed that the total effective rate and total bilirubin difference were higher and that the recurrent rate was lower in the herbal medicine group than in the western medicine group (RR: 1.20, 95% CI: 1.06-1.35, p=0.003, I2=52; MD: 0.52, 95% CI: -0.62 to 1.66, p=0.37, I2=0; RR: 0.35, 95% CI: 0.11-1.09, p=0.07, I2=0). The included RCTs had relatively poor quality and a small sample size. Conclusion: Treatment with herbal medicine was found to be partially effective in treating hepatitis C. The included RCTs had relatively poor quality and a small sample size. This study can serve as a foundation for further clinical studies on the development of treatment methods for hepatitis C based on herbal medicine.

Effect of Chuna Manual Therapy for Peripheral Facial Paralysis in Children : A Systematic Review (소아 말초성 안면마비에 대한 추나요법의 효과 : 체계적 문헌고찰)

  • Kim, Eui-Byeol;Kang, Ki-Wan;Kim, Min-Woo;Ko, Youn-Seok
    • The Journal of Churna Manual Medicine for Spine and Nerves
    • /
    • v.14 no.1
    • /
    • pp.1-11
    • /
    • 2019
  • Objectives : The purpose of this study is to review clinical studies about the effect of chuna manual therapy (CMT) for peripheral facial paralysis in children. Methods : In this review, we searched 11 electronic databases (Pubmed, Cochrane Library, EMBASE, CINAHL, CAJ, Oasis, NDSL, KISS, RISS, KISTI, Dbpia); We concluded our literature search in April 23, 2019. We included only randomized controlled trials (RCTs) of testing CMT for peripheral facial paralysis in children. The methodological quality of each RCT was assessed using the Cochrane risk of bias tool. The meta-analysis was performed by synthesizing outcome data of total efficacy rate (TER). Results : After screening papers, a total of 6 RCTs were selected and analyzed. In the 6 RCTs, patients(n=15-60 per study) were randomized into groups for treatment and control. Specifically, the treatment group received CMT, while the control group was concurrently given usual care, such as acupuncture and medicine. The meta-analysis showed that the treatment group receiving CMT alone showed significant improvement in TER, compared to the control group receiving acupuncture therapy alone(P<0.05). And the treatment group receiving CMT combined with usual care showed positive results, in terms of TER, compared to the control group receiving usual care, but was not statistically significant(P>0.05). Conclusions : Our analysis suggests that CMT has therapeutic effects for peripheral facial paralysis in children. However, to confirm this result, further investigation accompanied by high quality studies is required.

A Meta-analysis for the Effects of Exercise on Pulmonary Function in Patients with Ankylosing Spondylitis (강직성 척추염 환자의 폐기능에 미치는 운동효과에 대한 메타분석)

  • Kim, Eun-Jeong;Lee, Eun-Nam;Yu, Eun-Jeong
    • Journal of muscle and joint health
    • /
    • v.26 no.2
    • /
    • pp.141-154
    • /
    • 2019
  • Purpose: This study aimed to analyze the effects of exercise on pulmonary function in patients with ankylosing spondylitis (AS). Methods: Randomized controlled trials (RCTs) were identified by searching MEDLINE, EMBASE, CENTRAL, and CINAHL (through Jan 2019). Three reviewers independently retrieved articles, extracted data, and assessed methodological quality using the Cochrane's Risk of Bias for randomized studies. Results: Fourteen studies met the inclusion criteria with a total of 729 participants. CE (SMD 0.58, 95% CI 0.41~0.75, p<.001) and $VO_2peak$ (SMD 0.56, 95% CI 0.24~0.88, p=.001) had a significant effect on the most exercise interventions. As a secondary variable, BASFI (SMD -0.53, 95% CI -0.70~-0.37, p<.001), BASMI (SMD -0.75, 95% CI -0.92~-0.58, p<.001) showed an effect size of more than medium. However, PFT and QoL did not produce a significant results. Conclusion: Pulmonary involvement is common in patients with AS and might have disturbed functionality and exercise modality. Exercise can be an effective intervention to improve pulmonary function in patients with AS. More attention is needed to improve the chest and spinal mobility to maintain the appropriate pulmonary function. It is also necessary to consider how to construct a patient-tailored exercise program to increase performance, accuracy and safety of exercise.

Effects of Acupuncture after Rotator Cuff Surgery: A Systematic Review (회전근개 수술 후 침 치료의 효과: 체계적 문헌고찰)

  • Lee, Sang-Jin;Ko, You-Me;Park, Jung-Sik;Park, Tae-Yong;Lee, Jung-Han;Cho, Jae-Heung;Hwang, Eui-Hyoung;Kim, Kyoung-Ja;Choi, Mi-Young;Song, Yun-Kyung
    • Journal of Korean Medicine Rehabilitation
    • /
    • v.31 no.4
    • /
    • pp.25-34
    • /
    • 2021
  • Objectives This study was conducted to evaluate the therapeutic effect of acupuncture after rotator cuff surgery. Methods Key words such as rotator cuff surgery and acupuncture were searched in 10 databases (Ovid-Medline, Ovid-EMBASE, Ovid-AMED, Cochrane Library, China National Knowledge Infrastructure [CNKI], National Digital Science Library [NDSL], Koreanstudies Information Service System [KISS], Oriental medicine Advanced Searching Integrated System [OASIS], KoreaMed, KMBASE), and only suitable randomized controlled trials (RCTs) were selected. Results 6 RCTs were finally selected, and acupuncture showed positive results for pain relief and functional recovery after rotator cuff surgery. However, the analyzed 6 RCTs showed a high overall risk of bias. Conclusions In the future, RCTs with a higher level of evidence on the effect of acupuncture after rotator cuff surgery need to be continuously conducted.

Effects of Herbal Medicine after Total Knee Arthroplasty: A Systematic Review and Meta-Analysis (슬관절 전치환술 후 한약 치료의 효과: 체계적 문헌고찰과 메타분석)

  • Lee, Sang-Jin;Ko, You-Me;Park, Jung-Sik;Park, Tae-Yong;Lee, Jung-Han;Cho, Jae-Heung;Hwang, Eui-Hyoung;Kim, Kyoung-Ja;Choi, Mi-Young;Song, Yun-Kyung
    • Journal of Korean Medicine Rehabilitation
    • /
    • v.31 no.4
    • /
    • pp.35-47
    • /
    • 2021
  • Objectives This study was conducted to evaluate the therapeutic effect of herbal medicine after total knee arthroplasty. Methods Key words such as total knee arthroplasty and herbal medicine were searched in 10 databases (Ovid-Medline, Ovid-EMBASE, Ovid-AMED, Cochrane Library, China National Knowledge Infrastructure [CNKI], National Digital Science Library [NDSL], Koreanstudies Information Service System [KISS], Oriental medicine Advanced Searching Integrated System [OASIS], KoreaMed, KMBASE), and only suitable randomized controlled trials (RCTs) were selected. Results 8 RCTs were finally selected, and herbal medicine showed positive results for pain relief and functional recovery after total knee arthroplasty. However, the analyzed 8 RCTs showed a high overall risk of bias. Conclusions In the future, RCTs with a higher level of evidence on the effect of herbal medicine after total knee arthroplasty need to be continuously conducted.

How Shipping Company Satisfies Shippers Through Service Quality in South Korea: The Mediation Role of Trust

  • Roh, Taewoo;Park, Keun-Sik;Oh, Yeeun;Noh, Jinho
    • Journal of Korea Trade
    • /
    • v.25 no.5
    • /
    • pp.19-38
    • /
    • 2021
  • Purpose - This study aims to verify the direct causal relationship between cost competitiveness and global network competitiveness, which are the tangible service quality factors determined by the shipping company, which in turn affect the shipper's customer satisfaction. Additionally, we empirically investigate the intangible, related service qualities determined by shipping companies, such as operational competitiveness and customer relationship quality, and how these then positively affect customer satisfaction through the formation of trust. Therefore, we examine the mediating effect of trust formation among different contractors for shipping services. Design/methodology - In order to examine the shipping company's tangible and intangible service-qualities perceived by the shipper on customer satisfaction and the process of trust formation between contractors, we collected valid data from 114 respondents out of 200 distributed questionnaires. The respondents consisted of domestic freight forwarders who engage with domestic and international shipping and logistics agencies. Descriptive statistics, confirmatory factor analysis, reliability, convergent and discriminant validities, common method bias, and PLS-SEM (partial least square-structural equation model) were analyzed using the program STATA 16. Findings - The findings of this study are as follows. First, our results showed that all hypotheses assumed in this study had statistically significant supporting evidence. Second, it was found that the mediating effect of trust was significant in affecting the quality of intangible service- qualities for customer satisfaction. Third, through supplementary analysis, we found that the global network competitiveness of domestic shipping companies will increase in importance in the future. In conclusion, the theoretical and practical implications of these findings are presented. Originality/value - This study reaffirmed the traditional causal relationship between customer satisfaction and tangible service quality. Additionally, we also contribute to the literature on the understanding of the causal relationship between trust formation and customer satisfaction through intangible interactions from a long-term perspective.