• Title/Summary/Keyword: Sources of variation

Search Result 609, Processing Time 0.033 seconds

Phototaxis of Fish 6. Responce of Sea-bass to the White Lights (어류의 주광성에 관한 연구 6. 백색광에 대한 능성어의 반응)

  • 양용림
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.23 no.3
    • /
    • pp.137-143
    • /
    • 1987
  • The purpose of this study is to find the light intensity which induced maximum gathering rate and to observe the variation of the gathering rate both at daytime and night by using Sea-bass, Epinephelus septemfasciatus (Thunberg). An experimental tank (360 L$\times$50 W$\times$55H cm) was set up in a dark room. An illumination system was attached to the end of one side of the tank to control horizontal light intensity. Eight artificial light sources were prepared by combination of three with white light bulbs (10W, 60W, 100W) and eight filters. During the experiment water depth was maintained 50cm level in the tank. The tank was marked into six longitudinal sections each being 60cm long to observe the distribution of fish. The fish were acclimatized in dark condition for 50 minutes before the main experiment. Upon turning on the light, the number of fish in each section was counted 60 times every 30 seconds, and the gathering rate was obtained from the average number of fish in each section. The light intensity inducing maximum gathering rate was 24.13 lux (15.25~35.93 lux) at daytime and 0.41 lux (0.25~0.63 lux) at night. The variation of the gathering rate of fish in illumination time was great and did not show any definite pattern but fluctuated irregularly. Its different between daytime and night is remarkable.

  • PDF

Isotopic Differences among Zooplankton Taxa and Seasonal Variation of Zooplankton Community Coexisting with Microcystis (Microcystis와 공존하는 동물플랑크톤 군집의 계절변화 및 안정동위원소비의 차이)

  • Lee, Jae-Yong;Kim, Jai-Iu;Jung, Yu-Kyong;Kim, Bom-Chul
    • Korean Journal of Ecology and Environment
    • /
    • v.43 no.1
    • /
    • pp.1-10
    • /
    • 2010
  • We used stable isotope analysis to investigate the hypothesis that zooplankton were not able to utilize Microcystis as a food source. We also studied seasonal variation of the zooplankton community in a eutrophic Wangsong reservoir. The dominant copepod species changed from Cyclops vicinus to Thermocyclops taihokuensis. Density of zooplankton was suppressed by high density of Microcystis in June and the density of phytoplankton and chlorophyll a concentration was lowest in July. The difference in $\delta^{13}C$ and $\delta^{15}N$ between cladocerans (Daphnia galeata and Bosmina longirostris) and copepods showed the maximum difference of $12^{\circ}/_{\circ\circ}$ and $4^{\circ}/_{\circ\circ}$, respectively, indicating different energy sources and trophic positions between two taxonomic groups. The difference in $\delta^{13}C$ between Microcystis and zooplankton ranged from $3{\sim}7^{\circ}/_{\circ\circ}$, supporting the hypothesis that Microcystis could not be used as food source of zooplankton.

Evaluation on Air Quality inside Subway Driver Cabin by Monitoring PM, $CO_2$, and CO Levels (서울 일부 지하철 승무원석의 PM, 이산화탄소, 일산화탄소 모니터링에 의한 실내 공기질 특성 평가)

  • Kwag, Hyun-Suk;Jin, Ku-Won;Kim, Won;Yang, Won-Su;Choi, Sang-Jun;Park, Dong-Uk
    • Journal of Environmental Health Sciences
    • /
    • v.31 no.5 s.86
    • /
    • pp.379-386
    • /
    • 2005
  • [ $PM_{10},\;PM_{2.5},\;CO_2\;and\;CO$ ] in driver cabins of subway line from 5 to 8 were monitored from 07:00 through 21:00 (or 19:30 or 20:00) on May. Driver cabin of subway line 7 showed the highest $PM_{10},\;PM_{2.5},\;CO_2\;and\;CO$ concentrations. General Linear Model indicated that subway line, subway location (ground and underground track) and running time (morning and afternoon) significantly influenced the concentrations of $PM_{10},\;PM_{2.5},\;CO_2\;and\;CO$ (p=0.000). Daily profile of $PM_{10},\;PM_{2.5},\;CO_2\;and\;CO$, expressed as an 30 minutes average, showed similar variation pattern over day period. These concentrations showed the highest concentrations between 07:00 and 09:00 of rush hour, slightly dropped and again rose slightly after 18:00. In correlation analysis, significant relations among $PM_{10},\;PM_{2.5},\;CO_2\;and\;CO$ were detected (p<0.01). In particular, correlation coefficient between $PM_{10}\;and\;PM_{2.5}$ was highly significant (r=0.884). Regression analysis also concluded that $PM_{10}$ concentration significantly explained 71.4% of variation of $PM_{2.5}$ concentration (p=0.000, $R^2=0.714$). Correlations by CO with $PM_{10}\;and\;PM_{2.5}$ were 0.451 and 0.520, which were higher than those by $CO_2$. Further study is needed to examine the sources of $PM_{2.5}$ and CO in subway and to compare pollutants concentration among subway lines.

Semidiurnal Tidal Variation in Water Quality in Asan Bay during four Seasons (계절별로 조사한 조석에 따른 아산만의 수질 변동)

  • Kim, Se Hee;Shin, Yong Sik
    • Journal of Marine Life Science
    • /
    • v.5 no.1
    • /
    • pp.25-33
    • /
    • 2020
  • The Asan Bay, which has semi-diurnal tide with macro-tidal range, is affected by both freshwater discharge from the sluice gates in the sea dikes and tidal seawater inputs from the Yellow sea. Understanding water quality change in response to tides is important since tides can impact the short-term variations in physical and chemical water properties as well as the response of biological properties. The diel variations in water quality were seasonally investigated at 2 hour intervals from a fixed station in the Asan Bay. In the results, water temperature and salinity consistently fluctuated in phase or out of phase with tidal height. Especially salinity was positively correlated with tidal height. The concentrations of total suspended solids were higher in the bottom water than in the surface and fluctuated greatly over the tidal cycle recording higher values at low tide than at high tide. Nitrite+nitrate levels also fluctuated out of phase with tidal height and correlated negatively with tidal height. Other nutrients also showed a similar pattern. The pattern was distinct in July when freshwater was discharged before the field sampling. The concentrations of organic materials, total nitrogen and total phosphorus greatly fluctuated over the tidal cycle and were generally out of phase with tidal height. Most materials except particulate organic forms were correlated with salinity indicating that freshwater inputs were sources for the materials similarly to the dissolved inorganic nutrients. The results suggest that water quality (except dissolved oxygen and pH) and nutrients including organic materials was largely affected by tides in the Asan Bay.

Variation of Antimicrobial Susceptibility and Phage Types of Staphyloccus aureus Derived from Different Environmental Sources (서식환경에 따른 황색포도구균의 항균제감수성 및 Phage형별의 차이)

  • Cho, Dong-Taek;Lee, Yoo-Chul;Kim, Jin-Mo
    • The Journal of the Korean Society for Microbiology
    • /
    • v.20 no.1
    • /
    • pp.1-11
    • /
    • 1985
  • A total of 211 strains of Staphylococcus aureus which included 118 strains isolated from various clinical specimens of admitted patients of University Hospital with systemic or severe cases of infection and 93 strains from infected skin diseases of out-patients of dermatology clinic located in rural area, were tested for the antimicrobial susceptibility to the 12 drugs of common use and the phage typing. An these were subjected to the study of plasmid profile analysis for the molecular epidemiology of nosocomial infections. University Hospital(UH) isolates showed higher frequency of resistance than local clinic(LC) isolates against 10 drugs excluding tetracycline(Tc), and trimethoprim(Tp). The MIC of UH isolates were above than $128{\mu}g/ml$ against 9 drugs except Tc, gentamicin(Gm), and Tp, but LC isolates did not show such a high level of MIC. There was difference of MIC needed to inhibit 90% of strains(MIC90) against each drugs tested between two groups of UH and LC isolates. UH isolates showed 2 to 4 times higher value of MIC90 by two-fold serial dilution of drug concentration than LC isolates. Tp was considered as an effective drug in treatment of staphylococcal infections whereas ampicillin and Gm were appeared to be ineffective. Seventy-three strains(61.9%) of UH isolates and 70(69.9%) of LC were typable with phages from Colindale Reference Laboratory. The prevailing phage type of UH isolates belonged to lytic group II were 27 strains(22.9%) and those of LC isolates belonged to lytic group II were 23 strains(24.7%). Thirteen strains(11.0%) of UH isolates were multiply resistant to more than 5 drugs to 10 drugs but none of LC isolates. Through the lysis method of Kado and Liu followed by agarose gel electrophoresis, none of 211 strains showed plasmid profile. These results were confirmed by re-examination through the method of Birnboim and Doly.

  • PDF

Validation and comparison of volume measurements using 1 multidetector computed tomography and 5 cone-beam computed tomography protocols: An in vitro study

  • Juliana Andrea Correa, Travessas;Alessandra Mendonca, dos Santos;Rodrigo Pagliarini, Buligon;Nadia Assein, Arus;Priscila Fernanda Tiecher, da Silveira;Heraldo Luis Dias, da Silveira;Mariana Boessio, Vizzotto
    • Imaging Science in Dentistry
    • /
    • v.52 no.4
    • /
    • pp.399-408
    • /
    • 2022
  • Purpose: The purpose of this study was to compare volume measurements obtained using 2 image software packages on Digital Imaging and Communications in Medicine (DICOM) images acquired from 1 multidetector computed tomography and 5 cone-beam computed tomography devices, using different protocols for physical volume measurements. Materials and Methods: Four pieces of bovine leg were prepared. Marrow was removed from 3 pieces, leaving cortical bone exposed. The resulting space of 1 piece was filled with water, another was filled with propylene glycol, and the third was left unfilled. The marrow in the fourth sample was left fully intact. Volume measurements were obtained after importing DICOM images into the Dolphin Imaging 11.95 and ITK-SNAP software programs. Data were analyzed using 3-way analysis of variance with a generalized linear model to determine the effects of voxel size, software, and content on percentage mean volume differences between tomographic protocols. A significance level of 0.05 was used. Results: The intraclass correlation coefficients for intraobserver and interobserver reliability were, respectively, 0.915 and 0.764 for the Dolphin software and 0.894 and 0.766 for the ITK-SNAP software. Three sources of statistically significant variation were identified: the interaction between software and content (P=0.001), the main effect of content (P=0.014), and the main effect of software (P=0.001). Voxel size was not associated with statistically significant differences in volume measurements. Conclusion: Both content and software influenced the accuracy of volume measurements, especially when the content had gray values similar to those of the adjacent tissues.

Influences of Socio-demographic Factors, Health-related Recognitions and Dietary Behaviors on Use and Purchasing of Vegetables among Adult Women (일부지역 성인여성의 사회경제적요인, 건강관련의식구조 및 식생활태도와 채소류 소비에 미치는 영향)

  • Oh, Hae-Sook
    • The Korean Journal of Community Living Science
    • /
    • v.19 no.4
    • /
    • pp.481-495
    • /
    • 2008
  • The aim of this study was to investigate the effects of socio-demographic and health-related perceptions and twenty dietary behaviors on the superiority and preference, convenient use of and purchase motives of vegetables among 370 women(mean age 43.9) in Seoul and metropolitan and Gangwon area. Data was collected using a questionnaire developed in advanced studies. Almost all subjects rated vegetables more predominantly than grains or meats on the basis of health, diversity, and convenience to purchase. Recognition of healthly funcions of diet, purpose of diet and some dietary behaviors had influence on preference for vegetables. Those who recognized that diet had the function of disease control and prevention, knew the healthy options vegetables provide us, such as, preventing us from geriatric diseases, good sources of vitamins and minerals and considered other motives aside from health issues. From Pearsons's correlation analysis, it was revealed that sufficient time for meal preparation and pleasant eating and desirable life style and dietary attitudes, and a better understanding of nutrition were positively correlated with consumption of more vegetables and convenient use of vegetables. The subjects who recognized the ability of food to help prevent diseases, had a preference for vegetables and attitude to use nutritional knowledge and also considered the nutrition values of vegetables and environment friendliness. Everyday use of vegetables such as consuming a variety of different vegetables, a families favorite vegetables and variation of cooking methods had correlated positively with purchase motives. Therefore to encourage consumption of vegetables, it is important to notice three points continuously; first, practical information of nutritive values of vegetables, the contribution of vegetables in current animal protein foods centered diet and healthful functionalities. Second, the importance of regular diet and steadfast attitude and lifestyle. Finally, the quality of the market where the products are bought such as, quality control of freshness, sanitation, expression of producer and a pleasant environment to shop in.

  • PDF

Development of novel microsatellite markers to analyze the genetic structure of dog populations in Taiwan

  • Lai, Fang-Yu;Lin, Yu-Chen;Ding, Shih-Torng;Chang, Chi-Sheng;Chao, Wi-Lin;Wang, Pei-Hwa
    • Animal Bioscience
    • /
    • v.35 no.9
    • /
    • pp.1314-1326
    • /
    • 2022
  • Objective: Alongside the rise of animal-protection awareness in Taiwan, the public has been paying more attention to dog genetic deficiencies due to inbreeding in the pet market. The goal of this study was to isolate novel microsatellite markers for monitoring the genetic structure of domestic dog populations in Taiwan. Methods: A total of 113 DNA samples from three dog breeds-beagles (BEs), bichons (BIs), and schnauzers (SCs)-were used in subsequent polymorphic tests applying the 14 novel microsatellite markers that were isolated in this study. Results: The results showed that the high level of genetic diversity observed in these novel microsatellite markers provided strong discriminatory power. The estimated probability of identity (P(ID)) and the probability of identity among sibs (P(ID)sib) for the 14 novel microsatellite markers were 1.7×10-12 and 1.6×10-5, respectively. Furthermore, the power of exclusion for the 14 novel microsatellite markers was 99.98%. The neighbor-joining trees constructed among the three breeds indicated that the 14 sets of novel microsatellite markers were sufficient to correctly cluster the BEs, BIs, and SCs. The principal coordinate analysis plot showed that the dogs could be accurately separated by these 14 loci based on different breeds; moreover, the Beagles from different sources were also distinguished. The first, the second, and the third principal coordinates could be used to explain 44.15%, 26.35%, and 19.97% of the genetic variation. Conclusion: The results of this study could enable powerful monitoring of the genetic structure of domestic dog populations in Taiwan.

Comparison of fucosterol content in algae using high-performance liquid chromatography

  • Lee, Jeong Min;Jeon, Jae Hyuk;Yim, Mi-Jin;Choi, Grace;Lee, Myeong Seok;Park, Yun Gyeong;Lee, Dae-Sung
    • Fisheries and Aquatic Sciences
    • /
    • v.23 no.3
    • /
    • pp.9.1-9.6
    • /
    • 2020
  • Background: Fucosterol is a compound commonly found in algae that has various biological activities. The purpose of this study was to develop a high-performance liquid chromatography (HPLC) validation method for fucosterol and to compare the fucosterol contents of 11 algal species from Ulleungdo, Korea. Method: In this study, we successfully isolated and identified fucosterol from a 70% EtOH extract of Sargassum miyabei, and subsequently conducted specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, and precision analyses for development of an HPLC validation method. Fucosterol contents were compared using the established HPLC validation conditions. Results: We successfully isolated fucosterol from a 70% EtOH extract of S. miyabei and identified it based on spectroscopic analysis. On the basis of HPLC validation using the fucosterol isolated from S. miyabei, we confirmed specificity (8.5 min), linearity (R2 = 0.9998), LOD (3.20 ㎍ mL-1), LOQ (9.77 ㎍ mL-1), accuracy (intra-day and inter-day variation, 90-110%), and precision (RSD, 1.07%). Fucosterol contents in the 11 assessed algal species ranged from 0.22 to 81.67 mg g-1, with the highest content being recorded in a 70% EtOH extract of Desmarestia tabacoides (81.67 mg g-1), followed by that of Agarum clathratum (78.70 mg g-1). Conclusions: The results indicate that 70% EtOH extracts of D. tabacoides and A. clathratum containing fucosterol with various effects can be potential alternative sources of fucosterol.

Estimation of Genetic Parameters of Body Weight Traits in Ghezel Sheep

  • Baneh, Hasan;Hafezian, Seyed Hasan;Rashidi, Amir;Gholizadeh, Mohsen;Rahimi, Ghodrat
    • Asian-Australasian Journal of Animal Sciences
    • /
    • v.23 no.2
    • /
    • pp.149-153
    • /
    • 2010
  • The present study was carried out to estimate genetic parameters for body weight traits in Ghezel sheep. The data set used was records of 9,221 lambs from 180 sires and 5,060 dams for birth weight (BW), 7,206 lambs from 167 sires and 4,497 dams for weaning weight (WW) and 6,112 lambs from 157 sires and 3,841 dams for 6-months weight (6 MW), which were collected from 1999 to 2007 (9-years) at Ghezel sheep Breeding Station in west Azarbaijan. Variance components and corresponding genetic parameters were obtained with univariate analyses fitting animal models using restricted maximum likelihood (REML) methods. The most suitable model for each trait was determined based on log likelihood ratio tests. Birth year, lamb gender, type of birth, age of dam and herd were significant sources of variation on BW, WW and 6 MW (p<0.01). Direct estimate of heritability for BW, WW and 6 MW was 0.24, 0.29 and 0.37, respectively. The estimate of maternal permanent environmental variance as a proportion of phenotypic variance was 0.09 and 0.05 for BW and WW, respectively. The results of this study showed that genetic progress for growth traits is possible by selection.