• The Journal of the Acoustical Society of Korea
• /
• v.23 no.8
• /
• pp.562-569
• /
• 2004

An experiment for observation of the distribution of the seagrass (zostera marina) beds and characteristics of high-frequency backscattering by the photosynthesis was conducted off the coast. Acoustic data were taken as a function of the grazing angles and the relative azimuth angles on the seagrass beds of which bottom type was sandy-mud. The transmitted source signal was a 120 kHz CW waveform. Mapping of the seagrass beds distribution was drawn up using the seagrass backscattering strength with azimuth and grazing angles. The result of the comparison backscattering strength distribution of the seagrass beds was shown to be the similar to the photograph of real seagrass beds. The seagrass backscattering strength was also compared between day and night to verify the effects of the acoustical scattering by the bubbles of Photosynthetic oxygen formed on the seagrass. In these results. it is clear that observation of the seagrass beds between day and night showed the different characteristics because the bubbles of Photosynthetic oxygen affect the acoustical scattering.

• Asian-Australasian Journal of Animal Sciences
• /
• v.10 no.3
• /
• pp.293-297
• /
• 1997

Studies were designed to study the peri-parturient rise in strongyle faecal egg counts (FEC) in ewes grazing in a rubber plantation in North Sumatra, Indonesia. In three consecutive lambing seasons strongyle FEC of peri-parturient ewes and dry ewes were monitored from 2 to 3 weeks before lambing until 7 to 9 weeks post lambing to measure the magnitude and duration of the peri-parturient rise. A significant rise in FEC was observed during the post-parturient period in two of the three studies. FEC increased in the three studies from lambing day, and were elevated until 5 to 9 weeks following lambing. Lactating ewes shed on average 3 times more eggs than dry ewes. Lactating ewes were therefore considered as an important source of pasture infection. These findings are discussed in relation to the epidemiology and control of gastrointestinal nematodes in the humid tropics.

• Journal of Plant Biology
• /
• v.18 no.3
• /
• pp.87-91
• /
• 1975

Dry matter production of herb community in the Central Korea was studied. Generally, the maximum standing crop in the Central Korea can be observed during the period from July through September with somewhat differences between the herb communities of different floristic composition. Differences in standing crop between the communities of similar floristic composition in different regiions were insignificant while those between different floristitc community were relatively great, ranging from 308.7 d.w.g/$m^2$ in Phragmites prosturatus community. It seems that regional difference in standing crop of herb community of the same floristic composition in the Central Korea is greatly influenced by grazing effect rather than any other conditions. The maximum leaf area index (LAI) of different herb communities was observed during the period from July through September, ranging from 3.0 in Plantago asiatica community to 16.0 in Phragnites longivalvis community.

• Korean Journal of Ecology and Environment
• /
• v.38 no.spc
• /
• pp.17-21
• /
• 2005

We investigated the diel periodicity in the drift in relation to body size by field survey using the fourth instar grazing larvae of Micrasema quadriloba Martynov (Trichoptera, Brachycentridae) as a material. Although the larvae showed nocturnal drift periodicity, drift density in the nighttime was only twice that in the daytime. In both time periods, smaller individuals drifted significantly more, and the drift individuals in the daytime was the smallest in size (P< 0.05 in Sheffe's F). We discussed whether the drift of the fourth instar larvae drift behaviorally or accidentally considering larval size and food depletion.

• Journal of the korean society of oceanography
• /
• v.34 no.4
• /
• pp.236-240
• /
• 1999

A preliminary study was carried out to find characteristics of microbial trophic relations in hypoxic waters of Lake Shihwa in May and August 1996. Abundances of bacteria, viruses, and heterotrophic nanoflagellates (HNF) and HNF grazing on bacteria were measured. Dissolved O$_2$ (DO) saturation ranged from 13 to 34% in the bottom waters, and % of DO saturation strongly correlated with salinity. Ratios of HNF-to-bacteria abundance (42-118${\times}$10$^{-5}$) and biomass (0.06-0.25), and ratios of virus-to-bacteria abundance (110-297) in the hypoxic water were similar to those found in the surface layer, indicating similar structures of microbial abundances and trophic functions in hypoxicand surface waters during the study period. In the hypoxic water, an energy flow from organic matter to bacteria to HNF might operate as equally as in oxic surface layer.

• Journal of the korean society of oceanography
• /
• v.33 no.4
• /
• pp.205-211
• /
• 1998

Participating in a multi-disciplinary oceanography program in July 1997 in the vicinity of Tokdo, we studied the distributions of bacterial abundance and production along with those of phytoplankton and heterotrophic nanoflagellates. In the euphotic zone, chlorophyll a (chl a) concentrations ranged from 0.14 to 0.52 ${\mu}$g 1$^{-1}$. Bacterial abundance in the euphotic zone (0.12-0.21 ${\times}$ 10$^9$ cells 1$^{-1}$) in the study area was quite lower than that expected from the observed chi a concentration in the marine environment. The low bacterial abundance seemed to be due to active grazing pressure on bacteria. The fraction of primary production utilized by bacteria was also low(8-12%). Interestingly, surface water temperatures were love. at stations near islands compared to an offshore station located between Ulleungdo and Tokdo and the highest values of bacterial production and chi a were found at stations near islands, strongly indicating island mass effects.

• Journal of the korean society of oceanography
• /
• v.39 no.2
• /
• pp.136-147
• /
• 2004

Different model formulations in available models were compared with Microplankton-Detritus (MPB) model, and well documented FDM and ERSEM models were the candidate for these comparison. Different formulations in both candidate models were expressed in terms of MPD parameterization. Even though there are differences in the control of autotroph growth among models, it was found that some of the more important microplankton parameters expressed incomparable terms have broadly similar values in all the models. However, an important difference was proved to be the direct contribution of microheterotrophs to the Detritus compartment in FDM and ERSEM, whereas in MPD microplankton biomass passes to Detritus only by way of mesozooplankton grazing.

• Asian-Australasian Journal of Animal Sciences
• /
• v.8 no.3
• /
• pp.301-305
• /
• 1995

The study was conducted at village level in Pabna milkshed areas of Bangladesh to asses the existing feed and fodder sources of cattle. The results showed that the overall number of cattle per farm family was 7.17 and chicken represents highest number (15.57) per farm family in this area. The results also indicated that during monsoon season the bathan is planted with Vigna mungo and Lathyrus sativus and average grazing hours per day varied from 1.1 in October to 5.6 in February. In Summer, they were offered naturally grown Cynodon dactylon with supplementary feeding of rice straw. The study further showed that the highest (65.7%) feed scarcity was found during mid April to mid May followed by mid June. The cultivation of Vigna mungo was highest (76.71%) compared to Lathyrus sativus by the farmers in the bathan areas. The major constraint to cattle production is the scarcity of quality feed during mid October to mid November.

• Asian-Australasian Journal of Animal Sciences
• /
• v.12 no.3
• /
• pp.435-444
• /
• 1999

This paper summarizes the size and output of the major animal industries in Australia and the feed resource available to maintain production. The most important feed source is pasture but there is also extensive use of cereal grains, pulses and by-products in the intensive animal industries and in supplementing the diet of grazing animals. These resources must be used in ways that ensure sustainable production. We outline a number of Decision Support Systems such as GrazFeed, GrassGro, and AusPig which play an important role in optimizing the way in which resources are used. Waste management with respect to mineral pollution of water courses and methane production as a greenhouse gas are important issues for the animal industries and are also considered.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.181-181
• /
• 2013

Recently, nanostructure and the molecular orientation of organic thin films have been largely paid attention due to its importance in organic electronics such as organic thin film transistors (OTFTs), organic light emitting diodes (OLEDs), and organic photovoltaics (OPVs). Among various methods, the diffraction and scattering techniques based on synchrotron x-rays have shown powerful results in organic thin film systems. In this work, we introduce the in-situ annealing system installed at PLS-II (Pohang Light Source II) for organic thin films by simultaneously conducting various x-ray scattering measurements of x-ray reflectivity, conventional x-ray scattering, grazing incidence wide angle x-ray scattering (GI-WAXS) and so on. Using the in-situ measurement, we could obtain real time variation of nanostructure as well as molecular orientation during thermal annealing in metal-phthalocyanine thin films. The variation of surface and interface also could be simultaneously investigated by the x-ray reflectivity measurement.