• Title/Summary/Keyword: Population dynamics

Search Result 537, Processing Time 0.02 seconds

Effect of temperature on the development of the Common Grass Yellow, Eurema hecabe

  • Kim, Seonghyun;Park, Haechul;Park, Ingyun
    • International Journal of Industrial Entomology and Biomaterials
    • /
    • v.31 no.2
    • /
    • pp.35-39
    • /
    • 2015
  • The developmental responses of insects to temperature are important considerations in gaining a better understanding of their ecology and life histories. Temperature-dependent phenology models permit examination of the effects of temperature on the geographical distributions, population dynamics, and management of insects. Measurements of insect developmental and survival responses to temperature pose practical challenges that depend on the chosen modality, variability among individuals, and high mortality rates near the lower and upper threshold temperatures. Different temperature levels can significantly affect larval development of Eurema hecabe. The development of E. hecabe reared on leaves of Lespedeza cuneata was investigated at three temperature regimes (20, 25, and 30℃), a relative humidity of 60%, and a light:dark photoperiod of 14:10 h. The developmental time from larva to adult was 34.3, 20.6, and 17.9 d at temperatures of 20, 25, and 30℃, respectively. Pupal rate was 47.6%, 47.6%, and 61.9% at temperatures of 20, 25, and 30℃, respectively. The developmental threshold temperature estimated from larva to pupae was 8.1℃ with 381.7 degree-days. There is an increasing need for a standardized manual for rearing this butterfly species based on adequate knowledge of its ecology.

Reorienting Reorient : East Asia and 15th-19th Century Joseon

  • Kang, Sung-Ho
    • Asian review of World Histories
    • /
    • v.2 no.2
    • /
    • pp.197-216
    • /
    • 2014
  • This paper examines A. G. Frank's views about 15th-19th Korea (Joseon Dynasty) in his Reorient. A. G. Frank recognized that Korea might have played a great role in the international relations of East Asia, but he did not write systematically about it and he did not treat Korea as an independent player in the history of East Asia. I think the greatest limitation to his re-interpretation of East Asia is in that he depends too much on China's and Japan's perspective. In order to overcome Frank's shortcomings regarding the history of Korea, first I examine what Frank recognized about the Joseon dynasty between 1400 and 1800. Next I compare Joseon's development to that of China and Japan between 1400 and 1800. Frank compared Europe and East Asia (mainly China and Japan) from three aspects of quantities (population, production, productivity, and trade), qualities (science and technology), and mechanism (economic and financial institutions). With this research we insist that Joseon should not be dismissed in 15th-19th East Asia. The reasons are as follows. First, Joseon between 1400 and 1800 had developed economically as much as China and Japan. Second, Joseon had played a great role in connecting China and Japan and had a positive influence on the development of Japan. So we need to reappraise Reorient's view about East Asia. Only when role of Joseon can be correctly estimated, the dynamics and diversity of East Asia can be properly understood.

Characteristics of Digestion Dynamics of Rice and Oat Straw Relating to Microbial Digestion in the Rumen of Sheep Given High-Concentrate Diets

  • Goto, M.;Morio, T.;Kojima, E.;Nagano, Y.;Yamada, Y.;Horigane, A.;Yamada, H.
    • Asian-Australasian Journal of Animal Sciences
    • /
    • v.13 no.9
    • /
    • pp.1219-1227
    • /
    • 2000
  • Rumination behavior, in vivo digestibility of cell wall constituents, particle size reduction in the rumen, and retention time in the digestive tract of sheep were examined using rice and oat straw as roughage sources. The in sacco digestibility, rumen fermentation, and microbial population and internal adenosine 5-triphosphate (ATP) content were also determined under feeding conditions of high-roughage and high-concentrate diets. Chewing number and time in rumination behavior were higher with rice straw than with oat straw, while the in sacco and in vivo DMD of rice straw were consistently lower than those of oat straw. Rice straw also showed higher frequency of thinner and longer particles in the rumen contents and lower retention time in the whole digestive tract as compared to those of oat straw. Rice straw was more effective to maintain the ruminal pH than oat straw, being reflected in higher internal ATP content of large-type protozoa on the high- concentrate diet. Changes in the ruminal microflora by shifting from the low- to the high- concentrate diet were also different between rice and oat straw.

Ingestion on Planktonic Ciliates by Copepod Acartia hongi: A Laboratory Study (섬모충류에 대한 요각류 Acartia hongi의 섭식: 실험실 연구)

  • Yang, Eun-Jin;Choi, Joong-Ki
    • Ocean and Polar Research
    • /
    • v.31 no.3
    • /
    • pp.265-276
    • /
    • 2009
  • Acartia hongi is the most dominant and widespread planktonic copepod in Gyeonggi Bay, Yellow sea. Ingestion rates and selectivity of A. hongi on phytoplankton and planktonic ciliates were determined in the laboratory. Ingestion rates of A. hongi on planktonic ciliates and phytoplankton increased in proportion to prey concentration increase. When A. hongi was fed with various mixture combinations of planktonic ciliates and phytoplankton, their ingestion rate on ciliates tended to increase as the percentage of ciliates in prey biomass increased. Clearance rate of A. hongi on planktonic ciliates was higher than for phytoplankton in all experiments without regard to relative percent of ciliate biomass. This trend suggests that A. hongi was preferentially preying on planktonic ciliates. Under mixed prey availability, it is likely that selective feeding and higher clearance rate of planktonic ciliates by A. hongi is related to the higher nutritional value of ciliates compared to phytoplankton. Therefore, our results suggest that selective ciliate feeding by A. hongi will positively benefit its growth and abundance, and as a result negatively impact the population dynamics of planktonic ciliates in Gyeonggi Bay.

Quantitative Analysis of Leuconostoc mesenteroides and Lactobacillus plantarum Populations by a Competitive Polymerase Chain Reaction

  • Koh, Young-Ho;Kim, Myoung-Dong;Han, Nam-Soo;Seo, Jin-Ho
    • Journal of Microbiology and Biotechnology
    • /
    • v.12 no.5
    • /
    • pp.801-806
    • /
    • 2002
  • A multiplex competitive polymerase chain reaction (PCR) method was developed for the rapid identification and quantification of Leuconostoc mesnteroides and Lactobacillus plantarum populations which are the key microorganisms in kimchi fermentation. The strain-specific primers were designed to selectively amplify the target genes encoding 165 rRNA of L. plantarum and dextransucrase of L. mesenteroides. There was a linear relationship between the band intensity of PCR products and the number of colony forming units of each model organism. The PCR quantification method was compared with a traditional plate-counting method f3r the enumeration of the two lactic acid bacteria in a mixed suspension culture and also applied to a real food system, namely, watery kimchi. The population dynamics of the two model organisms in the mixed culture were reliably predictable by the competitive PCR analysis.

The Effect of Rainfall on the Water Quality of a Small Reservoir (Lake Wangkung, Korea)

  • Hwang, Gil-Son;Kim, Jae-Ok;Kim, Jai-Ku;Kim, Young-Chul;Kim, Bom-Chul
    • Korean Journal of Ecology and Environment
    • /
    • v.38 no.spc
    • /
    • pp.39-43
    • /
    • 2005
  • The dynamics of water quality with the storm events were analyzed in a small reservoir for irrigation, Lake Wangkung. Water quality of the inflowing stream fluctuated seasonally with the variation of flow rate. Thermal stratification was consistent from April to October below 2 m depths and anoxic layer was developed below 2 m depth in summer. The unique feature of temperature showed that thermal stratification was disrupted by a heavy rain event during monsoon, but hypolimnetic hypoxia were reestablished after a few days. Phosphorus and nitrogen increased immediately following storm events. The marked increase may be due to the input of P-rich storm runoff from the watershed. Internal phosphorus loading can be one of the explanations for TP increases in summer. When there was a storm, total populations of phytoplankton and zooplankton was reduced immediately following the storm, indicating possible flushing of algae and zooplankton. After a lag period of low-density the plankton population bloomed to a peak again within five days after the storm. Turbid water in lake became clear again which coincided with the time of the phytoplankton buildup. The results demonstrate that water quality is regulated greatly by rainfall intensity in Lake Wangkung.

A Study on the Dynamics and the Related Factors of Son Preference in Chon-buk and Chung-nam Area (전북 .충남지역 거주자의 남아선호 현상과 관련변인에 대한 연구)

  • 김용미
    • Korean Journal of Human Ecology
    • /
    • v.3 no.2
    • /
    • pp.58-67
    • /
    • 2000
  • The purpose of this study was to investigate the level and the reasons of son preference. and the relative importance of related variables among middle-and old-aged Koreans in Chon-buk and Chung-nam area. Subjects were 487 parents of high school girls(243 fathers and 244 mothers). with a mean age of 45.7 years. It was revealed that more than a half of the respondents(52.293) preferred'a son'for the first child, followed by'either nx'(32.6%) and'a daughter'(14.8%). For the second child, a son was preferred nlost(43.7%) , followed by'a daughter'(31.4%) and'either sex'(23.4%) . As the reasons of son preference,'to continue tradition and name of family'marked the highest score (3.42) , followed by'parents prefer son for various reasons'(3.37) , 'should have at least one son'(3.32). and'feel obliged to produce a son for in-law's sake'(3.06). It appeared that sociocultural background was more important for son Preference than individual, economic factors. The most important factors related to a strong son preference were the number of sons at the present, son preference for the first child, parental attitudes and expectations toward children. and income. Suggestions wire made in regard to efforts for gender equality in family and society. and the needs for parent education and population education.

  • PDF

Winter Biomass of Ulva Mats in a Rocky Intertidal Zone of the Southern Coast of Korea (겨울철 암반 조간대에서 갈파래 (Ulva species) 매트의 생물량)

  • 최태섭;최종관;박승민;김정하;김광용
    • Korean Journal of Environmental Biology
    • /
    • v.19 no.1
    • /
    • pp.37-42
    • /
    • 2001
  • The biomass of Ulva mats was surveyed in a lower rocky shore of the southern coast of Korea during the 1998-1999 winter. The population selected for the present study was located on the tidal zone ranging from 118 cm to 130 cm below mean sea level (MSL), where abundance of Ulvu species was highest. The biomass of Ulva species increased gradually from December 1998 until February 1999, reaching the maximum of 374 g dry wtㆍm$^{-2}$ in February. The biomass varied little among the sampling quadrats for each sampling time. Over the course of the study a total of 16 taxa were sampled from Ulva mats, of which 5 were macrophytes and 11 were macroinvertebrates. Rodophyta comprised 3 taxa, followed by Phaeophyta of 2 taxa, but there was no Chlorophyta except for Ulva species. The macrofaunal assemblage was consisted of 8 taxa of Mollusca, 2 Arthropoda and 1 Annelida. There was a dramatic increase in Mytilus sp. in February. Moreover, the trend of biomass were similar between some macroinvertebrates and Ulva species. The results suggested that macroinvertebrates may play an important role in nutrient dynamics as well as food web. Further experimental evidence may be necessary to explain the correlation between Ulva mats and abundance of coexisting macroinvertebrates.

  • PDF

Development of hydrogen-oxygen mixed gas torch for joining of vacuum glazing (진공유리 접합을 위한 수소-산소 혼합가스 토치 개발)

  • Hwang, Soon-Ho;Lee, Young-Lim;Jeon, Euy-Sik
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.10 no.11
    • /
    • pp.3074-3079
    • /
    • 2009
  • Efficient energy use becomes necessary since energy consumption has dramatically been increasing due to continuous economic development and population growth. In particular, high efficient vacuum glazing needs to be introduced to buildings where enormous energy loss occurs through windows and has been rarely used yet due to its high price and performance. Therefore, in this study, torch for glass welding was developed with CFD(Computational Fluid Dynamics) and experiments. Torch shape, nozzle diameter, nozzle arrangement etc. were mainly optimized and hydrogen-oxygen mixed gas fuels the torch. Finally, glass welding with the developed torch has been successful, showing that it can be used to develop economic vacuum glazing.

A Genetic-Based Optimization Model for Clustered Node Allocation System in a Distributed Environment (분산 환경에서 클러스터 노드 할당 시스템을 위한 유전자 기반 최적화 모델)

  • Park, Kyeong-mo
    • The KIPS Transactions:PartA
    • /
    • v.10A no.1
    • /
    • pp.15-24
    • /
    • 2003
  • In this paper, an optimization model for the clustered node allocation systems in the distributed computing environment is presented. In the presented model with a distributed file system framework, the dynamics of system behavior over times is carefully thought over the nodes and hence the functionality of the cluster monitor node to check the feasibility of the current set of clustered node allocation is given. The cluster monitor node of the node allocation system capable of distributing the parallel modules to clustered nodes provides a good allocation solution using Genetic Algorithms (GA). As a part of the experimental studies, the solution quality and computation time effects of varying GA experimental parameters, such as the encoding scheme, the genetic operators (crossover, mutations), the population size, and the number of node modules, and the comparative findings are presented.