• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.3 no.2
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• pp.66-78
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• 1992

Available data for the radar clutter, and the empirical and the theoretical models for the radar clutter have been collected and analyzed. Data sets and models from the remote sensing field have been studied extensively. Although the grazing angles used in remote sensing is larger than the angles normally encountered in radar clutter application, remote sensing field has the merit of abundance of data in much more detailed target classes. The remote sensing model is also superior to the normally used clutter models in the sense that each target class has its own model, rather than being generally characterized by assumed roughness parameters.

• Journal of environmental and Sanitary engineering
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• v.15 no.1
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• pp.1-6
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• 2000

A milky gray scum was observed at some water area of the lake Daecheong in the summer of 1997 and 1998. To identify a causing organism of scum and affecting factors, we observed the scum material by a phase contrast microscope and surveyed the phsico-chemical water quality during the outbreak of scum. The scum was found out to be clogging cysts of amoeboid protozoan, Asterocaelum sp.(Protozoea Sarcodina Aconchulinida), grazer of filamentous cyanobacteria, Anabaena genus. The protozoan scum appeared during Anabaena bloom period, which continued for a while. This protozoan was presumed acting as a regulator of Anabaena bloom in the lake Daecheong during the summer season. Moreover this is the first report on Asterocaelum sp. a grazing filamentous cyanobacteria occurred in Korean freshwater.

• Asian-Australasian Journal of Animal Sciences
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• v.3 no.3
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• pp.183-186
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• 1990

Monensin administered as a slow release capsule to Droughtmaster steers grazing mixed pastures containing Stylosanthes hamata or grass pastures fertilized with N, had no effect on growth rate over 111 day period. Monensin significantly increased the level of propionic acid (p<0.001) and decreased the level of butyric acid (p<0.01) in the rumen. The lack of response to monesin was partly attributed to the poor pasture conditions and growth rate of the steers during part of the experimental period. An implant of oestradiol improved growth rates during the period of poor forage quality and in the subsequent 56 days when pastures were of high quality following rain. Mean growth rates over the entire 157 days for control, monensin and monensin/oestradiol treatments were 0.37, 0.37 and 0.50 kg/d respectively. It was concluded that when pasture conditions are sufficient only for the maintenance of liveweight, production can be improved by an oestradiol implant but not by feeding an ionophore such as monensin.

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.2
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• pp.197-200
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• 1994

The study was conducted in the Bangladesh Agricultural University campus, Mymensingh, from July 1988 to June 1990. Five grazing fields consisting of five different vegetations were selected for this study. The specimen were collected from this study. The specimen were collected from the grazing fields by dragging method. The results revealed that two species of ticks namely Boophilus microplus and Haemaphysalis bispinosa were collected from five different vegetation. The highest incidence of both B. microplus and H. bispinosa were recorded during winter season and lowest in Monsoon for the year of 1988-89 and 1989-90. These two species were significantly occurred in Winter followed by Monsoon and Autumn.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.4
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• pp.387-392
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• 2016

This study was conducted to ameliorate the productive performance of Hanwoo cow using hill pasture grazing system. Twenty seven animals aged 9 were designed to divide with 3 groups which were Control (restricted concentrate and hay for 5 months), T1 (restricted concentrate and pasture grazing ad libitum for 5 months) and T2 (restricted concentrate, 30 g/head of mineral nutrients and pasture grazing ad libitum for 5 months). Average daily gains increased higher in the order of T2, Control and T1. The conception rate of Control, T1 and T2 after artificial insemination during post-grazing period were 88.9%, 100%, 100%, respectively. In conclusion, the results indicated that hill pasture grazing system might enhance not only the productive performance of Hanwoo cow but also profit for conventional feeding system.

• Journal of applied mathematics & informatics
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• v.32 no.5_6
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• pp.555-566
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• 2014

In this paper, we formulate two chemostat type models of phytoplankton and zooplankton population dynamics with instant nutrient recycling to study the role of viral infection on phytoplankton. The infection is transmitted only among phytoplankton population and it makes them more vulnerable to predation by zooplankton. It is observe that the chemostat system is very stable in the absence of viral infection but the presence of viral infection make the chemostat system sensitive with respect to the grazing rate of infected-phytoplankton by zooplankton. Further, if the grazing rate is less than certain threshold the system remain stable and exhibits Hopf-bifurcation after crossing it.

• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.680-690
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• 2020

In ocean environment, the sound speed gradient of seawater has an important influence on far field sound propagation. The FEM/BEM is used to decouple the vibroacoustic radiation of the spherical shell, and the Green function of the virtual source chain is adopted for decoupling. For far field radiated Sound Pressure Level (SPL), the Beam Displacement Ray normal Mode (BDRM) is employed. The vibration and near-/far-field radiated SPL of spherical shell is analyzed in shallow sea uniform layer, negative/positive gradient, negative thermocline environment, and deep-sea sound channel. Results show that the vibroacoustic radiation of spherical shell acted at 300Hz can be analogous to dipole. When the radiated field of the spherical shell is dominated by large-grazing-angle waves, it can be analogous to vertically distributed dipole, and the far field radiated SPL is lower; while similar to horizontally distributed dipole if dominated by small-grazing-angle waves, and the far field SPL is high.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.10
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• pp.1395-1403
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• 2012

The objective of the study was to quantify annual and seasonal differences in the chemical composition, in vitro gas production, in situ degradability and ruminal fermentation of grazing steers… diets. Diet samples were collected with four esophageal cannulated steers ($350{\pm}3$ kg BW); and four ruminally cannulated heifers ($342{\pm}1.5$ kg BW) were used to study the dry matter degradation and fermentation in rumen. Data were analyzed with repeated measurements split plot design. The crude protein, in vitro dry matter digestibility and metabolizable energy were higher during the first year of trial and in the summer (p<0.01). The values of calcium, phosphorus, magnesium, zinc and copper were higher in summer (p<0.05). The gas produced by the soluble and insoluble fractions, as well as the constant rate of gas production were greater in summer and fall (p<0.01). The ammonia nitrogen ($NH_3N$) and total volatile fatty acids concentrations in rumen, the soluble and degradable fractions, the constant rate of degradation and the effective degradability of DM and NDF were affected by year (p<0.05) and season (p<0.01). Our study provides new and useful knowledge for the formulation of protein, energetic and mineral supplements that grazing cattle need to improve their productive and reproductive performance.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.6
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• pp.872-879
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• 2007

A study was conducted to investigate the seasonal changes in nutrient composition of pasture, voluntary intake and digestibility of sheep grazing an introduced Leymus chinensis pasture located in western Jilin Province, China. The whole-plant of L. chinensis and the samples simulating ingestion by sheep (simulating sample) were collected in spring (May, 2004), summer (July, 2004), autumn (September, 2004) and the end of winter (April, 2005). The contents of gross energy (GE), organic matter (OM), crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF) and alkanes were determined. Voluntary intake and apparent digestibility of the nutrients in each season were also examined using 6 mature Chinese Northeast Merino ewes (differed among the seasons) grazing on a paddock of 1 ha size. The apparent digestibilities of GE, dry matter (DM), OM, CP, NDF and ADF of L. chinensis were significantly greater (p<0.05) in spring and summer than in autumn and winter. Metabolizable energy (ME) content was 12.13, 11.62, 8.66 and 10.40 MJ/kg DM for L. chinensis in spring, summer, autumn and winter respectively, and the corresponding voluntary feed intakes were 91, 119, 59 and 58 g/d per kg metabolic weight ($LW^{0.75}$). The ME contents and DM intakes in autumn and winter were significantly lower than in spring and summer (p<0.05). The intake of L. chinensis pasture was sufficient to provide ME requirements for maintenance by the dry ewes in all the seasons, but inadequate for maintenance protein requirement in winter. (Supported by funds from National Basic Research Program of China, Grant No. 2007CB106800).

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.9
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• pp.1228-1234
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• 2000

The reported study was conducted on range managed Malpura ewes that were non-breeding empty, were at an advanced stage of pregnancy, and were in early lactation, under a protocol of free grazing with concentrate supplementation at 1.00, 1.25 and 1.50% of their body weight to assess their plane of nutrition and nutrient intake. The biomass yield of pasture plots was 1689, 1820 and 2912 kg/ha in pregnancy, lactation and empty phases, respectively. In addition to natural shrubs and forbs, Cenchrus ciliaris (36.4%) and dead litter (31.6%) were the major component of pasture vegetation during pregnancy. The dead litter disappeared during the lactation and empty phase with a concomitant increase in distribution of Cenchrus ciliaris to 73.0 and 87.2% respectively. The daily dry matter consumption from supplemental concentrate and free grazing was 70.1, 57.3 and 63.5 g/kg $W^{0.75}/d$ with concentrate to roughage ratio of 40:60, 47:53 and 33:67 in pregnancy, lactation and empty phases respectively. Digestibility of DM and OM were similar in the three phases while CP digestibility was higher (p<0.0l) during lactation than other two phases. Digestibility of NDF, ADF and cellulose were higher (p<0.0l) in empty than pregnancy and lactation, while hemicellulose digestibility was similar in lactation and empty and lower in pregnancy phase. The ewes in ~hases of pregnancy, lactation and empty consumed 7.1, 7.7 and 6.1 g DCP and 197.2, 214.6 and 232.5 kcal DE/kg $W^{0.75}/d$ respectively. It is concluded that ewes maintained on semi-arid Cenchrus dominated pasture with concentrate supplementation during pregnancy, lactation and empty phases consumed 45.2, 45.1 and 35.2 g DCP/Mcal ME respectively.