• Korean Journal of Environment and Ecology
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• v.32 no.5
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• pp.507-512
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• 2018

Three natural Pinus thunbergii stands in southern Korea were studied to investigate stem density, biomass expansion factors, allometric equations and stand biomass. Stand ages of stand 1, 2 and 3 were 15, 29 and 45 years old, respectively. Three $10m{\times}10m$ plots were set up, five sample trees were cut and roots of three sample trees were excavated for dimension analysis in each stand. Stem density of stand 1, 2 and 3 were $0.450g/cm^3$, $0.440/cm^3$ and $0.457g/cm^3$, respectively, and there was no significant difference among the three stands. Biomass expansion factors of above-ground and total tree decreased with increasing stand age. Above-ground biomass expansion factor of stand 1 was significantly higher than those of stand 2 and 3, and total tree biomass expansion factor of stand 1 was significantly higher than that of stand 3. Allometric equations were developed for the 15 sample trees of the three stands based on D or $D^2H$. Above-ground biomass of stand 1, 2 and 3 were 50.72t/ha, 89.92t/ha, 194.07t/ha, respectively, and total tree biomass of stand 1, 2 and 3 were 61.62t/ha, 113.12t/ha, 248.36t/ha, respetively.

• Fisheries and Aquatic Sciences
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• v.27 no.6
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• pp.356-365
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• 2024

The study was conducted in the Terie River between January and April 2022. The objectives of the study were to assess the fish species composition, determine the length-weight relationship and condition factor and assess the water quality of the river using international water quality guideline for aquatic life. Gillnets with different mesh sizes, 4, 6, 8 and 10 cm were used to collect fish specimens in both dry and wet seasons. Immediately after capture, the total length (TL) and total weight (TW) of each individual were measured in centimeters and grams, respectively, and their relationship was determined using the power function. The physicochemical water quality parameters were analyzed using standard procedures and wagtech portable water quality Kits and Secchi Disk apparatus. A total of 667 fish specimens were collected from the Terie River, 410 and 257 in dry and wet seasons respectively. A total of six fish species, Oreochromis niloticus, Labeobarbus intermedius, Labeobarbus nedgia, Labeobarbus beso, Clarias gariepinus, and Ramius loti were recorded. For length-weight relationship and condition factor analysis, more abundant fish species (O. niloticus and L. intermedius) which were found in both seasons were selected. The length and weight relationship of L. intermedius were TW = 0.0073TL^3.04 in dry and TW = 0.0337TL^2.59 in we season indicated isometric and negative allometric growth respectively. While O. niloticus showed negative allometric growth, TW = 0.096TL^2.44 and TW = 0.0335 TL^2.76 in dry and wet seasons, respectively. The mean Fulton condition factor (FCF) of L. intermidus were 0.85 ± 0.03 and 0.94 ± 0.25 in dry and wet seasons, respectively. The FCF of O. niloticus was 1.70 ± 0.13 and 1.73 ± 0.12 in dry and wet seasons respectively. Except for ammonia, the physicochemical water quality parameters were with the permissible limit for aquatic life and are suitable for fishes Terie River. The river has commercially important fish specimens that could be used for food security and livelihood improvement. However, there is very limited fishing activity in the river due to less awareness on the value of fishes. Therefore, sustainable fishery development should be done in the river.

• Journal of Korean Society of Forest Science
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• v.112 no.1
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• pp.71-82
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• 2023

Forest biomass is used as a representative indicator of forest size, maturity, and productivity. Therefore, quantitative evaluation is important for management and harvest as well as the evaluation of ecosystem functions and services including CO₂ absorption. The allometric equation is a widely used method for estimating the value of each component through the relative growth rate of plants. Recently, studies indicated that the relative growth of trees is changing because of the increased CO₂ concentration in the atmosphere and the resulting climate change, raising the need to review the previously developed relative growth models and coefficients. In this study, the height-diameter at breast height (DBH) relationships of four major tree species in Korea [(Pinus densiflora (PD), Larix kaempferi (LK), Quercus variabilis (QV), and Quercus mongolica (QM)] were analyzed using the 5th-7th National Forest Inventory (NFI) data. Furthermore, these results were compared with the present yield table from the National Institute for Forest Science. This analysis revealed that the expected height for the same DBH increased as the NFI progressed. For example, in model analysis, the expected heights for PD, LK, QV, and QM for DBH of 25 cm were 12.48, 19.17, 14.47, and 13.19 m, respectively, in the 5th NFI data. In the 7th NFI data, these values were estimated as 13.61 (+9.1%), 21.58 (+12.7%), 15.76 (+8.9%), and 13.93 m (+5.6%), respectively. These results indicate that the major tree species in South Korean forests currently are more vigorous in height growth than in diameter growth when compared to the height-DBH development trends by tree species identified through past survey data.

• Fisheries and Aquatic Sciences
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• v.26 no.3
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• pp.224-233
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• 2023

This research was conducted at Langgur City, Southeast Maluku Regency, Maluku Province, Eastern Indonesia from November 2020 to February 2021 to study biological aspects of roundscads (Decapterus spp.) which consist of species composition, sex ratio, gonad maturation level, size distribution, length-weight relationship and condition factor. Samples were collected at traditional fish market in Langgur City. Fish samples collected at the market were put into cool box and then brought to the laboratory for further examination. Fish samples were identified, separated based on species, dissected to determine their sex and gonad maturation stage and then measured. Totally, there were 290 specimen collected which consist of five species namely Decapterus kurroides, D. macarellus, D. macrosoma, D. muroadsi and D. russelli. Sex ratio between male and female for all species showed 1:1. Gonad maturation level showed that stage I and II have higher percentage than stage III and IV indicates immature fish more dominant compare to mature one. Among five species found, D. macarellus has larger size while the smaller belongs to D. muroadsi. Results of length-weight relationship analysis showed that roundscads inhabiting Southeast Maluku waters have isometric and negative allometric growth pattern with relative condition factor around 1.00.

• Fisheries and Aquatic Sciences
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• v.27 no.6
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• pp.392-409
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• 2024

The present study aims to analyze the biological aspects and population dynamics of Indian mackerel in Barru waters. Data was collected in Barru for 11 months, from June 2022 to April 2023. The observed parameters of biological aspects included gonadal maturation stages (GMSs), size at first gonadal maturation, and length-weight relationship. Meanwhile, the aspects of population dynamics encompass age group, growth, mortality rate, and exploitation rate. Data analysis consisted of morphological selection of general maturation stages, Spearman-Kärber method in estimating gonadal first maturation size, Bhattacharya method in identifying age group, von Bertalanffy function through FISAT II to measure growth (L_∞ and K), Pauly Model to estimate mortality rate, Beverton & Holt Model to estimate Y/R, and virtual population analysis (VPA) analysis to estimate stock and fish yield. The results demonstrated that GMS I was observed to be dominant, followed by stages II and III. The initial gonadal maturation was estimated to be 17.98-19.28 cm (FL) for females and 17.98-19.27 cm (FL) for males. The length-weight relationship in male and female Indian mackerels indicated a positive allometric growth. The mode grouping analysis results from the fork length measurement revealed three age groups. It was also identified that the asymptotic length (L_∞) = 29.5 cm (fork length), growth rate coefficient (K) = 0.46 per year, and theoretical age at zero length (t₀) = -0.3576 per year. Total mortality (Z) = 2.67 per year, natural mortality (M) = 1.10 per year, fishing mortality (F) = 1.57 per year, and exploitation rate (E) = 0.59, the actual Y/R = 0.083 gram/recruitment, and optimal Y/R 0.03 gram/recruitment. Fishing mortality is higher than the natural mortality rate, and a high exploitation value (E > 0.5) also reflects over-exploitation. VPA analysis on fish yields and stock estimation reported a highly exploited rate between the 11.5 cm and 14.5 cm length classes and an exceeding current yield of 467.07 tons/year with a recommended yield of 233.53 tons/year to ensure population sustainability.

• Journal of Korean Society of Rural Planning
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• v.21 no.4
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• pp.27-33
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• 2015

Forest ecosystem is considered as an important stepping stone to minimize the impact of climate change. However, the rapid urbanization has caused fragmentation of forest ecosystem. The fragmentation of forest patch results in edge effect which brings about adverse impacts on forest function and structure. Degradation of forest ecosystem decreases carbon sequestration because edge effect reduces productivity. Therefore, we analyzed the impact of forest edge effect on forest ecosystem carbon stock change in Seongnam-si, Gyeonggi-do. We used connectivity analysis to determine forest edge and core area. The field study sites were selected with considering forest age, density, class and soil type. Secondly, forest carbon stock was calculated with allometric equation. The soil carbon stock was derived from Walkely-Black method. Lastly, Mann-Whitney test was conducted to validate differences between carbon stock in edge and core area. As a result of study, the connectivity analysis was effective to determine forest edge and core. The core and edge of forest patch showed different composition of tree species and soil properties. Carbon stock per tree in the edge area was lower than that in the core area. However, the difference of soil organic carbon content between the edge and core were relatively small. This assessment can be applied for the conservation of forest patch as well as quantitative assessment on the forest carbon stock change caused by fragmentation.

• Journal of Biomedical Engineering Research
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• v.27 no.6
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• pp.323-331
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• 2006

The purpose of this study was to investigate the effect of performing a cognitive task during treadmill walking on the stride rate variability. Ten university students(age $24.0{\pm}0.25$, height $172{\pm}3.1cm$, weight $66{\pm}5.3kg$) were participated in dual task experiments which consist of both walking alone and walking with a cognitive task. Two-back task was selected for the cognitive task since it did not have learning effect during the experimental procedure.3D motion analysis system was used to measure subject's position data by changing walking speed with 4.8, 5.6, 6.4, 6.8, and 7.2 km/hr. Stride rate was calculated by the time between heel contact and heel contact. Accuracy rate of a cognitive task during walking, coefficient of variance, allometric scaling methods and Fano factor were used to estimated the stride rate variability. As the walking speed increased, accuracy rate decreased and the logarithmic value of Fano factor increased which showed the statistical difference. Thus it can be concluded that the gait control mechanism is distracted by the secondary attention focus which is the cognitive task ie. two-back task. Further study is needed to clarify this by increasing the number of subject and experiment time.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.7
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• pp.1108-1114
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• 2007

Twenty eight non-lactating and non-pregnant adult Serra da Estrela ewes, ranging in body condition score (BCS) from 1 to 4 were used to study the relationships between BCS, live weight (LW), body composition and fat partition. Ewes were slaughtered and their kidney knob and channel fat (KKCF), sternal fat (STF) and omental plus mesenteric fat (OMF) were separated and weighed. Left sides of carcasses as well as the respective lumbar joints were then dissected into muscle, bone and subcutaneous (SCF) and intermuscular fat (IMF). The relationship between LW and BCS was studied using data from 1,396 observations on 63 ewes from the same flock and it was found to be linear. Regression analysis was also used to describe the relationships among BCS and/or LW and weights (kg) and percentages in empty body weight (EBW) of dissected tissues. The prediction of weights and percentages in EBW of total fat (TF) and of all fat depots afforded by BCS was better than that provided by LW. Only the weight of muscle and the percentage of bone in the EBW were more efficiently predicted by LW than by BCS. IMF represented the largest fat depot with a BCS of 1 and 2, whereas SCF was the most important site of fat deposition with a BCS of 3 and 4. Allometric coefficients for each fat depot in TF suggest that the fat deposition order in ewes from this breed is: IMF, OMF, SCF and KKCF. Results demonstrate that BCS is a better predictor than LW of body reserves in this breed and that LJ is a suitable anatomical region to evaluate BCS.

• Journal of Plant Biology
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• v.15 no.3
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• pp.1-8
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• 1972

A comparison between the productivity of the evergreen needle pine(Pinus densiflora) and of the deciduous broad leaved oak(Quercus mongolica) stands, which is located near Choon-Chun city, Kangwon dist. have been established. The pine stand had a stand density of 938 trees per ha and oak stand had of 638 trees per ha. The diameter at breast height (D) and the height of tree (H) of each tree were measured in sample plot of 800$m^2$. Twelve standard sample trees chose from the sample area felled down, and then weighed the stem, branches and leaves separately, according to both the stratified clip technique and the stem analysis. The vertical distribution of photosynthetic system was arranged effectively for high productivity in the productive structure of both trees. The allometric relation between D2H and dry weight of stem (Ws), branches (Wb) and leaves (Wl) of pine were approximated by log Ws=0.6212 log D2H-0.5383 log Wb=0.4681 log D2H-0.7236 log Wl=0.2582 log D2H-5.1567 and those of oak were approximated by log Ws=0.5125 log D2H＋0.0231 log Wb=0.5125 log D2H-0.3755 log Wl=0.8721 log D2H-2.9710 From the above, the standing crops of pine and oak in the sample area were estimated to be as much as 38.83ton and 48.11 ton of dry matter, above ground, per ha, respectively. Annual net production as the sum of the biomass newly formed during one year was appraised at 12.66ton/ha.yr in pine stand and at 8.74 ton/ha.yr in oak. The reason of high productivity of pine stand compared with oak might be resulted from much more about 4 times of the amount of the photosynthetic system, but less non-photosynthetic one of pine than those of oak. To increase the productivity of the forest stands investigated it was necessary to make densly a stand density, to be abundant in the inorganic nutrients and to preserve much water in soil to conserve the litters.

• Fisheries and Aquatic Sciences
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• v.26 no.5
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• pp.318-335
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• 2023

It is important to understand the biological aspects of fish for fishing management. This study was conducted from February through October 2021. A total of 1,629 fishes were collected using different fishing gears. The length-weight relationship is a power curve for all fishes and showed a significant (r² > 0.8). All fishes revealed a negative allometric growth pattern except Labeobarbus intermedius. Oreochromis niloticus (1.714 ± 0.009) was found in better condition than other fish species (analysis of variance [ANOVA], p < 0.05). The length at maturity was 24.0 cm and 25.4 cm total length (TL), 28.9 cm and 28.2 cm fork length, and 53.2 cm and 57.5 cm TL for females and males of O. niloticus, L. intermedius and Clarias gariepinus, respectively. Fecundity was ranged between 100-947 eggs/g with absolute fecundity (AF) of 468-3,832 eggs, 200-1,000 eggs/g with AF of 2,752-136,420 eggs, and 505-900 eggs/g with AF of 2,000-6,404 eggs for O. niloticus, C. gariepinus, and L. intermedius, respectively. Their respective mean fecundity was 1,490 ± 91, 23,330 ± 5,070, and 3,096 ± 273 eggs, respectively. Mean fecundity revealed a significant variation between size classes and species (ANOVA, p < 0.05). The fecundity length and fecundity-body weight relationships except (O. niloticus) of fishes were curvilinear while the gonad weight (GW)-fecundity relationship was linear for all fish species. The fecundity was moderately associated with increasing length than body weight, and GW for all fishes (r² > 0.6). In conclusion, a tangible management setup is required to sustain the use of fish in the reservoir.