• Title/Summary/Keyword: in-migration rate

Search Result 436, Processing Time 0.026 seconds

Seasonal Distribution, Egg Production and Feeding by the Marine Copepod Calanus sinicus in Asan Bay, Korea

  • Park, Chul
    • Journal of the korean society of oceanography
    • /
    • v.32 no.2
    • /
    • pp.85-92
    • /
    • 1997
  • Seasonality in abundance and egg production was investigated for Calanus sinicus in Asan Bay, Korea, and feeding effort was measured in the laboratory condition. Although abundances of this species in this bay showed only one Peak in spring, egg Production showed two peaks, spring and fall, in this bay. Potential of year-round egg Production was also found. Food availability judged by the particulate organic carbon (POC) concentration was usually more than enough in this bay. High egg Production in fall resulted in spring Peak in abundance. But high egg Production in spring did not result in summer or fall Peak in abundance. Low abundances in summer and fall were believed to be the result of long range horizontal migration out to the central Part of the Yellow Sea. The highest average egg Production by the Population of this species was 16.3 eggs female-'day-'. Maximum e99 Production by an individual was 39.0 e99s female$^{-1}$ day$^{-1}$, which yielded 30.7% of specific egg Production rate in terms of body carbon content with the carbon contents of 44.44$^{\mu}$gC and 0.35 $^{\mu}$gC for individual adult female and egg, respectively. Clearance rate (F) measured in the laboratory condition decreased exponentially with the increase of food concentrations, as expected. The asymptote of F was 3.17 ml copepod$^{-1}$ h$^{-1}$. When this value and the minimum concentration of POC measured in the field were applied under the assumption of continuous feeding in the nature, the calculated gross efficient of egg production was 41.6% in case of average egg production of the population. Violation of the assumption of diurnal feeding rhythm and application of the minimum concentration of POC may offset the influence on calculation each other.

  • PDF

miR-15b induced by platelet-derived growth factor signaling is required for vascular smooth muscle cell proliferation

  • Kim, Sunghwan;Kang, Hara
    • BMB Reports
    • /
    • v.46 no.11
    • /
    • pp.550-554
    • /
    • 2013
  • The platelet-derived growth factor (PDGF) signaling pathway is essential for inducing a dedifferentiated state of vascular smooth muscle cells (VSMCs). Activation of PDGF inhibits smooth muscle cell (SMC)-specific gene expression and increases the rate of proliferation and migration, leading to dedifferentiation of VSMCs. Recently, microRNAs have been shown to play a critical role in the modulation of the VSMC phenotype in response to extracellular signals. However, little is known about microRNAs regulated by PDGF in VSMCs. Herein, we identify microRNA- 15b (miR-15b) as a mediator of VSMC phenotype regulation upon PDGF signaling. We demonstrate that miR-15b is induced by PDGF in pulmonary artery smooth muscle cells and is critical for PDGF-mediated repression of SMC-specific genes. In addition, we show that miR-15b promotes cell proliferation. These results indicate that PDGF signaling regulates SMC-specific gene expression and cell proliferation by modulating the expression of miR-15b to induce a dedifferentiated state in the VSMCs.

Effect of stem cell culture on thermal stability (줄기세포배양액이 열 안정성에 미치는 영향)

  • Moon, Ji-Sun
    • Journal of the Korean Applied Science and Technology
    • /
    • v.38 no.1
    • /
    • pp.186-195
    • /
    • 2021
  • In this study, when stem cell culture solution is used as a cosmetic ingredient, one of the most prominent problems is that the ingredients generally have low thermal stability. Therefore, in this study, in order to find out how the stem cell culture medium is heated or preserved at high temperature, the effect of various effects of stem cells on the various effects of the stem cells was investigated. Investigated. As a result of the experiment, the wound healing assay confirmed that the cell migration increased after 6 hours, and after 24 hours, it was confirmed that the cell mobility was increased and cell division was promoted, thereby being concentrated. As a result of investigating the amount of transdermal water loss by preparing a cosmetic product containing stem cell culture solution, it was confirmed that the culture solution addition group showed an improvement rate of 31% compared to the non-added group, thereby helping in skin wound recovery. As a result of this, it is considered that this point should be considered when the stem cell culture medium is used as an active ingredient in cosmetics in the future.

A Study on Analysis of Industrial Injury Characteristics of Aging Workers in Agriculture

  • Kim, Yuchang;Kim, Daesu;Park, Kyunghwan;Kim, Daesik
    • Journal of the Ergonomics Society of Korea
    • /
    • v.33 no.6
    • /
    • pp.477-486
    • /
    • 2014
  • Objective:This study aims to devise industrial injury prevention measures by analyzing industrial injury characteristics including the status of industrial injuries, source of industrial injury and accident type in order to prevent aging workers' industrial injuries that account for more than half in the workplaces in agriculture. Background: Continuous migration from farm to city takes place among young people in rural areas in Korea, a traditionally agricultural country due to rapid industrialization and economic development. The aging rate in rural areas in 2013 was 37.3%, about three times higher than the total aging rate of 12.2% in Korea. According to industrial injury statistics of the Ministry of Employment and Labor, the number of industrial injuries in agriculture shows an uptrend and the industrial injuries of aging workers account for more than 50% each year. Method: Of the 2,970 industrial injury cases occurred in the workplaces in agriculture for five years during 2008 and 2012 offered by a national agency related to health and safety, this study analyzed 1,767 industrial injury cases of aging workers. Results: As a result of an analysis on aging workers' industrial injuries by company size in agriculture, 89.8% of the total number of industrial injuries were analyzed to occur in small scale company. According to aging workers' industrial injuries by source of industrial injury and accident type, the outdoor floor and a fall were analyzed to be the highest at 16.5% and 26.1%, respectively. Conclusion: This study analyzed aging workers' industrial injuries by company size, age, job duration, accident severity, gender, nationality, the source of industrial injury and accident type in order to identify industrial injury characteristics in agriculture. Application: The identification of industrial injury characteristics of aging workers in agriculture is judged to be helpful to devising effective measures to prevent industrial injuries.

Soil Properties in Relation to Elastic Wave (탄성파를 이용한 흙의 특성연구)

  • 조계춘;이인모
    • Journal of the Korean Geotechnical Society
    • /
    • v.18 no.6
    • /
    • pp.83-101
    • /
    • 2002
  • Elastic waves provide an important information about the soil mass in the near-surface. Soil properties in relation to elastic wave parameters are clarified to facilitate the application of geophysical technique to soil characterization. As an example, experiments are performed to gain further insight into the behavior of unsaturated particulate materials using bender elements. The small strain stiffness is continuously measured on specimens subjected to drying, and changes in stiffness are related to changes in interparticle forces such as capillarity, bonding due to ion sharing, buttress effect due to fine migration, and cementation due to salt precipitation. The rate of menisci regeneration is studied after a perturbation as well. Finally, several phenomena associated with the evolution of capillary forces during drying are identified.

A Mechanistic Model for In-Reactor Densification of U$O_2$ (U$O_2$ 핵연료의 노내 기계론적 고밀화 모형)

  • Woan Hwang;Keum Seok Seo;Ho Chun Suk
    • Nuclear Engineering and Technology
    • /
    • v.17 no.2
    • /
    • pp.116-128
    • /
    • 1985
  • Considering vacancy generation and migration in grain and sink at grain boundary, a mechanistic densification model which is dependent on UO$_2$ temperature and microstructure has been developed. This densification model is a function of time, fission rate, temperature, density, pore size distribution and grain size. The resultant equation derived in this model which is different from Assmann and Stehle's resultant equations for four temperature regions, can be applied directly for all the pellet temperatures. The predictions of the present densification model very well agreed with the experimental data. This model well predicts absolute magnitude and trend in comparison with the empirical algorithm used in KFEDA code.

  • PDF

Effect of Exchangeable Cation on Radionuclide Diffusion In Compacted Bentonite

  • Park, Jong-Won;Park, Hyun-Soo;Dennis W. Oscarson
    • Nuclear Engineering and Technology
    • /
    • v.28 no.3
    • /
    • pp.274-279
    • /
    • 1996
  • Diffusion coefficient is a critical parameter for predicting radiological source term(migration rate and flux of radionuclide) through given near field conditions in spent fuel or high level waste repository. The effect of exchangeable cation-$Na^+$ and $Ca^{2+} - on the diffusion of $I^- \;and^3H$ (as HTO) in compacted bentonite was examined using a through-diffusion method. Bentonite material used here was compacted to a density of 1.3 Mg/m$^3$, and Na-bentonite was saturated with a solution of 100 mol NaCl/m$^3$ and Ca-bentonite with 50 $mol\;CaCl_2$/m$^3$. The results show that effective diffusion coefficients are generally higher by a factor of two to five in Ca-than Na-clay. This is attributed to the larger particle size of Ca-compared to Na-bentonite; hence, Ca-bentonite has a greater proportion of relatively large pores, which make a greater contribution to mass transport than small pores. Although the nature of the exchangeable cation affects mass diffusion in compacted bentonite, the effect is small and not likely to influence performance assessment modeling of compacted bentonite-based barriers.

  • PDF

Separation and Determination of Citric Acid by Ion Chromatography in Radioactive Concrete Waste

  • Hyejin Cho;Jai Il Park;Tae-Hong Park;Hye-Ryun Cho
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
    • /
    • v.22 no.1
    • /
    • pp.27-35
    • /
    • 2024
  • During the dismantling of nuclear facilities, a large quantity of radioactive concrete is generated and chelating agents are required for the decontamination process. However, disposing of environmentally persistent chelated wastes without eliminating the chelating agents might increase the rate of radionuclide migration. This paper reports a rapid and straightforward ion chromatography method for the quantification of citric acid (CA), a commonly used chelating agent. The findings demonstrate acceptable recovery yields, linearities, and reproducibilities of the simulated samples, confirming the validity of the proposed method. The selectivity of the proposed method was confirmed by effectively separating CA from gluconic acid, a common constituent in concretes. The limits of detection and quantification of the method were 0.679 and 2.059 mg·L-1, respectively, while the recovery yield, indicative of the consistency between theoretical and experimental concentrations, was 85%. The method was also employed for the quantification of CA in a real concrete sample. These results highlight the potential of this approach for CA detection in radioactive concrete waste, as well as in other types of nuclear wastes.

A Effective Role of Education on International Trade and Income Distribution (국제무역과 소득분배에 대한 교육의 역할)

  • Yoo, Il-Seon
    • International Area Studies Review
    • /
    • v.14 no.3
    • /
    • pp.454-476
    • /
    • 2010
  • In this paper is two-step trade model introduced. It is assumed that countries have 3 basic factors- capital(K), land (Z)and population(N)-as national factor endowments. As the first step, education 'produces' 'educated labor(EL)' which embodies new knowledge or new technology by using the population and capital as inputs. As the second step, manufacturing goods is produced with EL and uneducated labor(UL), and agriculture goods with land and UL. According to this model, the higher the increase rate of capital in a country is, the lower the usage rate of land is, the lower the increase rate of discount is, the country tends to export the manufacturing goods and import the agriculture goods. Trade widens the discrepancy of increase rate of EL in both countries but reduces the gap of increase rate of relative wage of EL as far as the gap of usage rate is not so big. Trade also affect real income rather than nominal income. This model can be extended to explain the migration from rural areas to urban areas when the manufacturing sector and education organization exist in urban area while the agricultural sector exist in rural area.

Finless porpoise, Neophocaena phocaenoides, Distribution in the South Sea of Korea (남해안 상괭이(Finless porpoise)의 분포)

  • Choi, Seok-Gwan;Park, Kyum-Joon;Kim, Hyun-Woo;Lee, Young-Ran;Park, Ji-Eun;Moon, Dae-Yeon;An, Yong-Rock
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.43 no.6
    • /
    • pp.665-669
    • /
    • 2010
  • To confirm the distributon of finless porpoise, Neophocaena phocaenoides, in the South Sea of Korea, data on bycatch, stranding, and drifting of finless porpoises from 1999 to 2009 were used and a sighting survey was conducted from the R/V Tamgu No. 9 and 10 in June and November, 2009 and March, 2010. The total number of bycaught, stranded, and drifting finless porpoises was 607, with position being known for 186 of these. At the center of Yeosu, there were few position data on bycaught, stranded, and drifting finless porpoises, and data could not confirm the distribution of finless porpoises. Thus, there were limits on the usefulness of bycaught, stranded, and drifting data for confirming the distribution of finless porpoises. In the three sighting surveys, the sighting rate was highest at 0.231 ind./n.m. in the western South Sea in June, 2009. Sighting rate was less than 0.1 ind./n.m. in November, 2009 and March, 2010. This is likely to be due to seasonal migration in western South Sea. All sighting rates in the eastern South Sea were over 0.13 ind./n.m.. According to the results of the sighting survey, finless porpoises are distributed around the islands and inner bay along the path of the research vessel in the South Sea. There were numerous finless porpoises in the offshore areas of Mokpo, Yeosu, Tongyeong, Dadaepo, and Gaduk-do. This study will be utilized as part of a future abundance assessment of finless porpoise in the South Sea of Korea.