• 제목/요약/키워드: Longevity Risk

검색결과 42건 처리시간 0.028초

유채로부터 갓으로 유전자이동에 의한 교잡종의 휴면에 따른 잡초화 가능성 (Dormancy Associated Weedy Risk of the F1 Hybrid Resulted from Gene Flow from Oilseed Rape to Mustard)

  • 임연화;육민정;장전걸;나경주;박수형;김도순
    • Weed & Turfgrass Science
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    • 제4권1호
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    • pp.35-43
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    • 2015
  • 본 연구는 유채의 화분이동으로 근연종 갓과의 교잡을 통해 형성된 교잡종의 발아휴면특성과 월하 및 월동성을 평가하여 교잡종의 잡초화 가능성을 예측하고자 본 연구를 수행하였다. 교잡종은 부본인 유채와 모본인 갓에 비해 전반적인 발아특성이 갓에 근접한 중간적인 특성을 보여주었으며, 휴면성도 41.1%로 갓에 근접한 높은 휴면성을 보여주었다. 수확 직후 종자를 토양에 매립하여 월하특성을 평가한 결과 표토보다는 3 cm 토심에서 월등히 높은 월하특성을 보여주었으며, 월하기간과 상관없이 3 cm 토심조건에서 부본인 유채에 비해 매우 높고 모본인 갓에 비해 약간 높은 월하특성을 보여주었다. 반면 종자의 월동특성은 월하특성과 반대로 표토조건에서 교잡종이 부모종보다 높은 월동성을 가지는 것으로 확인되었다. 따라서 유채-갓 교잡종은 휴면성이 비교적 높고 월하 및 월동성이 높아 잡초화 가능성이 있음을 시사한다. 유채-갓 교잡종의 보다 명확한 잡초화 가능성 평가를 위해서는 교잡종의 종자생산 가능성 및 자연 생태계 적응성 여부에 대한 추가적인 연구가 필요하다.

Suitability of stochastic models for mortality projection in Korea: a follow-up discussion

  • Le, Thu Thi Ngoc;Kwon, Hyuk-Sung
    • Communications for Statistical Applications and Methods
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    • 제28권2호
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    • pp.171-188
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    • 2021
  • Due to an increased demand for longevity risk analysis, various stochastic models have been suggested to evaluate uncertainly in estimated life expectancy and the associated value of future annuity payments. Recently updated data allow us to analyze mortality for a longer historical period and extended age ranges. This study followed up previous case studies using up-to-date empirical data on Korean mortality and the recently developed R package StMoMo for stochastic mortality models analysis. The suitability of stochastic mortality models, focusing on retirement ages, was investigated with goodness-of-fit, validity of models, and ability of generating reasonable sets of simulation paths of future mortality. Comparisons were made across various types of models. Based on the selected models, the variability of important estimated measures associated with pension, annuity, and reverse mortgage were quantified using simulations.

평균회귀확률과정을 이용한 2요인 사망률 모형 (A Two Factor Model with Mean Reverting Process for Stochastic Mortality)

  • 이강수;조재훈
    • 응용통계연구
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    • 제28권3호
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    • pp.393-406
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    • 2015
  • 본 논문은 2요인(two-factor) 사망률 모형에 평균회귀모형(mean reverting process)을 적용하여 2요인의 확률적 변동을 모형화하여 사망률리스크(mortality risk)와 장수리스크(longevity risk)를 분석하였다. 최근 고령사회로 진입한 국가들에서 사망률 개선의 둔화가 관측되고 있는 시점에서 기존의 선형증가 또는 감소의 사망률 개선 모형을 보완함에 그 목적을 두었다. 영국의 1991~2015년 사망률 자료를 이용하여 제시한 모형의 모수를 메트로폴리스 알고리듬을 이용해 추정하였고 추정된 모수 값을 이용하여 다수 시뮬레이션을 통하여 장기간의 미래 사망률 예측값을 계산하였다. 평균회귀 모형의 특성으로 인해 약 60년의 시간이 지난 뒤부터는 사망률 개선이 거의 사라져 사망률이 일정한 값에 근접하였다. 사망률 개선이 둔화되는 현상이 관측되는 특정 집단(국가, 사회)의 경우 2요인 평균회귀 모형은 장기간 사망률 예측방법의 대안으로 간주될 것으로 기대되며, 모형의 응용으로서 평균회귀율의 추정결과로부터 사망률 개선의 속도를 계량화하는 기준을 제시하였다. 끝으로, 2014년~2040 기간의 사망률 예측값을 이용하여 25년 만기 장수채권의 발행가격을 산출하였다.

The effect of clinical performance on the survival estimates of direct restorations

  • Kim, Kyou-Li;NamGung, Cheol;Cho, Byeong-Hoon
    • Restorative Dentistry and Endodontics
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    • 제38권1호
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    • pp.11-20
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    • 2013
  • Objectives: In most retrospective studies, the clinical performance of restorations had not been considered in survival analysis. This study investigated the effect of including the clinically unacceptable cases according to modified United States Public Health Service (USPHS) criteria into the failed data on the survival analysis of direct restorations as to the longevity and prognostic variables. Materials and Methods: Nine hundred and sixty-seven direct restorations were evaluated. The data of 204 retreated restorations were collected from the records, and clinical performance of 763 restorations in function was evaluated according to modified USPHS criteria by two observers. The longevity and prognostic variables of the restorations were compared with a factor of involving clinically unacceptable cases into the failures using Kaplan-Meier survival analysis and Cox proportional hazard model. Results: The median survival times of amalgam, composite resin and glass ionomer were 11.8, 11.0 and 6.8 years, respectively. Glass ionomer showed significantly lower longevity than composite resin and amalgam. When clinically unacceptable restorations were included into the failure, the median survival times of them decreased to 8.9, 9.7 and 6.4 years, respectively. Conclusions: After considering the clinical performance, composite resin was the only material that showed a difference in the longevity (p < 0.05) and the significantly higher relative risk of student group than professor group disappeared in operator groups. Even in the design of retrospective study, clinical evaluation needs to be included.

Relationship of dairy heifer reproduction with survival to first calving, milk yield and culling risk in the first lactation

  • Fodor, Istvan;Lang, Zsolt;Ozsvari, Laszlo
    • Asian-Australasian Journal of Animal Sciences
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    • 제33권8호
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    • pp.1360-1368
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    • 2020
  • Objective: The aim of our study was to determine the associations of heifer reproductive performance with survival up to the first calving, first-lactation milk yield, and the probability of being culled within 50 days after first calving. Methods: Data from 33 large Holstein-Friesian commercial dairy herds were gathered from the official milk recording database in Hungary. The data of heifers first inseminated between January 1, 2011 and December 31, 2014 were analyzed retrospectively, using Cox proportional hazards models, competing risks models, multivariate linear and logistic mixed-effects models. Results: Heifers (n = 35,128) with younger age at conception were more likely to remain in the herd until calving, and each additional month in age at conception increased culling risk by 5.1%. Season of birth was related to first-lactation milk yield (MY1; n = 19,931), with cows born in autumn having the highest milk production (p<0.001). The highest MY1 was achieved by heifers that first calved between 22.00 and 25.99 months of age. Heifers that calved in autumn had the highest MY1, whereas calving in summer was related to the lowest milk production (p<0.001). The risk of culling within 50 days in milk in first lactation (n = 21,225) increased along with first calving age, e.g. heifers that first calved after 30 months of age were 5.52-times more likely to be culled compared to heifers that calved before 22 months of age (p<0.001). Calving difficulty was related to higher culling risk in early lactation (p<0.001). Heifers that required caesarean section were 24.01-times more likely to leave the herd within 50 days after first calving compared to heifers that needed no assistance (p<0.001). Conclusion: Reproductive performance of replacement heifers is closely linked to longevity and milk production in dairy herds.

Pollen-Mediated Gene Flow between Glufosinate Ammonium-Tolerant GM and Non-GM Rice

  • Lee, Seung-Yeob;Kim, Min-Soo;Kim, Hyo-Jin;Ahn, Jeong-Ho;Baek, So-Hyeon;Shin, Woon-Chul;Kim, Hyun-Soon
    • Journal of Plant Biotechnology
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    • 제34권1호
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    • pp.47-53
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    • 2007
  • To assess the risk of genetically modified (GM) rice on the agricultural ecosystem, agronomic characteristics, pollen longevity and outcrossing rate between GM (Iksan 483 and Milyang 204) and non-GM (their wild types and female parents) varieties were investigated using the bar gene as a tracer marker in paddy field. The agronomic characteristics of two GM rice were similar to their female-parents (non-GM rice) except heading date and 1,000 grain weight of Iksan 483, and they did not show a difference by the introgression of the bar gene as the genetic traits of rice varieties. Pollen viability was more than 90% just after shedding, and it was rapidly decreased below 50% at 5 minutes after shedding both GM and non-GM varieties. The Pollen longevity was lost after 30 minutes of anthesis. When the distance of gene flow from GM to non-GM rice detected to 6 m from the edge of GM rice plant, the maximum distance of pollen dispersal was 4.5m and 3.9m in Iksan 483 and Milyang 204, respectively, and that was increased in order of west, south, east, and north to the dominant wind direction, west-south. Mean outcrossing rate was very low as 0.003 and 0.001% within 1.5 m from the edge of Iksan 483 and Milyang 204, and the GM hybrids by the pollen dispersal did not detected over 4.5 m from the edge of GM rice plant. The results may help to establish the strategy which reduce the risk of pollen-mediated gene flow between GM and non-GM rice.

폐경후 여성호르몬 보충요법 (Postmenopausal Hormone Replacement Therapy)

  • 박형무
    • 정신신체의학
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    • 제4권1호
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    • pp.98-108
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    • 1996
  • Korean women are now living almost 1/3 of their life after menopause. Sex-steroid hormone deficiency adversely affect various fields of physical & mental activity and quality of life during this period. Therefore, replacement of deficient hormone is thought to be natural therapeutic modality. Postmenopausal syndrome is recently redefined as an endocrinopathy with both short-and long-term sequelae, as a result of cessation of ovarian function. Hormone replacement therapy taken at or near time of menopause alleviates shot-term acute menopausal symptoms such as vasomotor disturbances and psychological problems. HRT also beneficially affects some of intermediate symptoms such as urogenital atrophy and cutaneous problems. The major benefits of long-term use were reductions in risk of long-term sequelae, that is, total fracture by 50-60%, cardiovascular disease by 50% and cerebrovascular disease by 30-40%, respectively. In addition, HRT may also positively influence Alzheimer's disease, reduce the colorectal cancer risk and increase longevity of the life. In conclusion, all postmenopausal women should consider preventive HRT when there are no contraindications.

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왜도 예측을 이용한 Lee-Carter 모형의 주택연금 리스크 분석 (Actuarial analysis of a reverse mortgage applying a modified Lee-Carter model based on the projection of the skewness of the mortality)

  • 이항석;박상대;백혜연
    • 응용통계연구
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    • 제31권1호
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    • pp.77-96
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    • 2018
  • 주택연금은 계약기간이 확정되어 있지 않기 때문에 계약 종료 시점에 대한 확률분포 예측이 장수리스크 관리를 위하여 중요하다. 따라서 고령화의 주요인인 기대수명의 연장은 연금 재정건전성에 심각한 영향을 끼칠 수 있기 때문에 사망률의 개선 추세가 적절히 반영된 사망률 예측 연구가 선행될 필요가 있다. 본 연구에서는 Lee-Carter (LC) 모형과 연생모형을 이용하여 주택연금 계리모형에 사망률 개선 효과를 반영하였다. 전통적 LC 모형을 통한 사망률 예측 방식은 미래 사망률이 지나치게 개선되는 현상을 보이고 있기 때문에 사망률 개선효과를 조금 더 적절한 수준으로 보정하고자 본 연구에서는 사망확률 분포의 편중을 나타내는 왜도를 활용한 LC 모형을 적용하였다. 왜도 예측 방식을 LC 모형에 적용한 방법론을 사용하여 주택연금 월 지급금을 산출해본 결과 전통적 LC 모형의 사망률 예측보다 사망률 개선효과를 더 적게 반영하여 더 큰 월 지급금이 산출되었고, 왜도 활용 LC 모형에 의한 이러한 결과는 장수 리스크를 덜 왜곡한다는 데 의의가 있다고 볼 수 있다. 본 연구 결과는 사망률 감소 추세를 적절하게 반영한 위험률을 계산하여 주택연금의 발행기관 및 보증기관의 적정한 월 지급금 지급과 차후 월 지급금의 과대지급으로 인한 지급불능을 방지할 수 있는 리스크 관리 방법으로 이용될 수도 있다.

학생들의 정신건강을 위한 감정자유기법(EFT): 체계적 문헌고찰 (Emotional Freedom Techniques (EFT) for Students' Mental Health: A Systematic Review)

  • 이승환;정보은;채한;임정화
    • 동의신경정신과학회지
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    • 제28권3호
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    • pp.165-182
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    • 2017
  • Objectives: The purpose of this systematic review was to understand clinical usefulness of Emotional Freedom Techniques (EFT) on students' mental health. Methods: Ten databases were included to extract clinical studies on effects of EFT intervention with students. Characteristics of selected studies were described, and biases were assessed with Risk of Bias (RoB) or Risk of Bias Assessment for Non-Randomized Studies (RoBANS). Results: A total of 14 clinical trials were extracted for analysis. There were 8 randomized-controlled trials (RCTs), 2 non-randomized-controlled trials (nRCTs), and 4 before-after studies. EFT have significant clinical usefulness in public speaking anxiety, test anxiety, stress, depression, learning related emotions, adolescent anxiety, and eating issues. The risk of selection bias in most studies was high or uncertain. Conclusions: EFT is an effective clinical technique for managing students' mental health issues. However, the included studies have been conducted with relatively poor quality and small sample size. Clinical trials with high quality study design and well-designed EFT education programs are needed to generalize clinical usefulness.

구조방정식모형을 이용한 개인연금 가입의향의 결정요인 분석 (An analysis of determinants of purchase intension of individual pension using structural equation model)

  • 이찬희;정홍주
    • 응용통계연구
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    • 제29권3호
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    • pp.409-424
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    • 2016
  • 본 연구는 노후대비를 위한 재무수단 중에서 중요성이 커지고 있는 개인연금의 가입의향에 영향을 주는 심리요인과 금융요인 간의 인과관계를 종합적으로분석하고자 하였다. 이를 위해 전국 7대도시에 거주하는 928명의 일반인을 대상으로 실시한 설문자료를 토대로 구조방정식모형(SEM)을 이용하여 실증분석하였다. 구조방정식에 의한 실증분석결과, 개인연금 미가입자의 신규가입의향에 있어 장수에 대한 가능성과 대처효용성은 장수에 대한 정서인 두려움과 걱정을 완전매개로 하여 개인연금의 신규가입의향에 영향을 주는 것으로 나타났다. 그리고 보험사 신뢰와 위험감수성향은 직접적으로 개인연금의 신규가입의향에 영향을 주며, 특히 개인연금 가입의향에 대하여 보험사 신뢰가 가장 중요한 요인임을 보여주었다. 또한 개인연금 기가입자의 추가가입의향에 있어서는 보험사 신뢰만이 개인연금 추가가입의향에 직접적으로 영향을 주는 것으로 나타났다. 본 연구를 통하여 장수 관련 정서적 측면이 개인연금 미가입 고객을 대상으로 한 마케팅 활동에 도움이 될 것으로 기대된다. 아울러 보험사 신뢰가 미래의 개인연금 신규가입뿐만 아니라 추가가입의향에 가장 큰 영향을 미치므로 보험사의 신뢰도를 높이기 위한 노력이 긴요함을 시사한다.