• Korean journal of applied entomology
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• v.49 no.3
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• pp.199-204
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• 2010

The seasonal fluctuation of the large 28-spotted lady beetle, Henosepilachna vigintioctomaculata (Motschulsky), was observed in potato fields of Gangneung region, Gangwondo Province. The effects of their leaf consumption over a 24 hour period and developmental periods by different temperatures were investigated, and then the developmental threshold (DT) and effective cumulative temperature (ET) of each stage were calculated. Various developmental stages of H. vigintioctomaculata were captured in the fields from May to September, with three peaks in late May, late June, and late August. Leaf consumption by larval stages increased with the development of instar. The 4th instar larvae consumed potato leaves much more than other stages. Egg hatchability and emergence rate of H. vigintioctomaculata were lower at $10^{\circ}C$ and $30^{\circ}C$, but higher at around $20{\sim}23^{\circ}C$. The developmental periods of each stage became shorter as temperature increased; 90 days at $10^{\circ}C$, 40 days at $20^{\circ}C$ and 25 days at $25^{\circ}C$. Base on developmental velocity to temperature, calculated DT and ET were $7.3^{\circ}C$ and 83.

• 한국생태학회:학술대회논문집
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• 1999.05a
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• pp.55-62
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• 1999

Four species of Paraphysomonas collected from the fast- ice covered area Syowa Station, East Ongul Island ($69^{\circ}00'S,\;39^{\circ}35'$) ,Antarctica occurred in the seawater throughout the year and occasionally in the sea ice. P.. antarctica is distributed to a water depth of 35m at 51.3 during the period from August 1983 to January 1984 and also down to 600m St. 5 in September 1983 at cell concentrations of 300-350 cells/ml. The Paraphysomonas spp. were dominant during the period from July to November 1983 in the area studied. The mode of the occurrence and vertical distribution of Paraphysomonas apparently coresponds to those of the bacteria and orgarnic debris-like matter in the seawater. The main components of the plankton population in the area studied, under ice-covered conditions, are Paraphysomonas, Choanoflagellates and bacteria. This work clarified that Paraphysomonas is one o f the most important bacterivores in the microbial loop of the Antarctic marine ecosystem.

• Molecules and Cells
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• v.39 no.10
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• pp.715-721
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• 2016

Plants have become physiologically adapted to a seasonally shifting environment by evolving many sensory mechanisms. Seasonal flowering is a good example of adaptation to local environmental demands and is crucial for maximizing reproductive fitness. Photoperiod and temperature are major environmental stimuli that control flowering through expression of a floral inducer, FLOWERING LOCUS T (FT) protein. Recent discoveries made using the model plant Arabidopsis thaliana have shown that the functions of photoreceptors are essential for the timing of FT gene induction, via modulation of the transcriptional activator CONSTANS (CO) at transcriptional and post-translational levels in response to seasonal variations. The activation of FT transcription by the fine-tuned CO protein enables plants to switch from vegetative growth to flowering under inductive environmental conditions. The present review briefly summarizes our current understanding of the molecular mechanisms by which the information of environmental stimuli is sensed and transduced to trigger FT induction in leaves.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.05a
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• pp.210-215
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• 2004

The Purpose of this study are to develop the simulation(Tank model, Rainfall-runoff model) for the estimation of wily river discharge and for evaluation of wily pollutant loads from the watersheds of the objected basin area. As apply this constructed Tank model to Nakdong river region, we evaluated the wily river discharge of Nakdong river from use-land conditions, precipitation and evaporation data of 3 years(from 1998 to 2000) and investigate the seasonal fluctuation of SS, COD, TN, TP inflowing into Nakdong river. The result shows that summer has high pollutant level than winter in seasonal characteristic and the down stream has high pollutant level than the upper stream. The annual average of SS, COD, TN, TP flawing in Nakdong river(Samranjin) was estimated each 691ton-COD/year, 1854.2ton-SS/year, 382.8ton-TN/year and 13.0ton- TP/year.

• Ocean and Polar Research
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• v.34 no.4
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• pp.403-411
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• 2012

Among others, a question that has long been unanswered is why the seasonal variation of volume transport is larger in the Soya and Korea/Tsushima Straits than in the Tsugaru Strait. An attempt is made to answer this question in terms of the island rule with friction being taken into account. The problem is idealized as a simple model. The model results indicate that volume transport through a channel is determined not only by the circulation created around the adjacent island but also by those created around the neighboring islands farther away. The latter is due to the presence of bottom friction in the channels. The volume transports through the Korea/Tsushima, Tsugaru and Soya Straits estimated from the model using observed wind data show the general pattern of observed seasonality, although they contain large errors associated with the uncertain frictional parameter employed in the model. The model indicates that the observed seasonality arises essentially from the fact that wind stress curl changes its sign, from negative in the summer to positive in winter, following a large fluctuation of zero-stress curl latitude east of Hokkaido.

• Korean Journal of Environmental Biology
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• v.20 no.3
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• pp.268-275
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• 2002

Seasonal variation in reproductive condition of the Pacific oyster Crassostrea gigas was investigated from a suspended cultured oyster population in Gosung Bay, South Korea using histological techniques, Gametogenesis of oysters initiated in February when water temperature reached 11 to $13^\circ{C}$. Increase in oocyte size and the number resulting in follicle expansion was observed from March to May First spawning of oysters observed in mid Jun when the surface water temperature reached 22 to $25^\circ{C}$. Spawning activity of oysters extended from mid June to late September with two marked spawning peaks in June and August. Most oysters collected from October to December exhibited few residual eggs in packed follicles exhibiting a typical spent condition. No gametes were observed from December to February from oysters collected in the Bay. Gonadal development of oysters in the Bay seemed to follow a seasonal fluctuation in environmental conditions such as water temperature and food availability in the water column. Spawning of oysters in late June was in part associated with sudden drop in salinity due to vast amount of freshwater input in the Bay after the summer flooding. Sex ratio of oysters was 59.5% male and 39.8% female. Less than 1 percent (0.6%) of the oysters examined were hermaphrodite; few eggs were observed in testis.

• Korean journal of applied entomology
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• v.41 no.3
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• pp.177-181
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• 2002

This study investigated seasonal occurrence of Frankliniella occidentalis and its damage on chrysanthemum from 1999 to 2000. F. occidentalis adults were attracted to yellow sticky traps from early April to harvesting time in the field. The highest densities were observed from late April to mid-June in spring culture and from mid-August (just after transplanting) to early September in autumn culture respectively. Seasonal fluctuation in a PVC green house was similar to that in the field. Number of insects per flower were higher in the green house than that in the field. Leaf damages due to the insects were observed from mid-May and increased as chrysanthemum grows (R$^2$ = 0.9200-0.9887$\^$**/, p> 0.01).

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2003.10a
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• pp.151-151
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• 2003

• Journal of Plant Biology
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• v.20 no.3
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• pp.135-140
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• 1977

A series of observations of phytoplankton were made at seven station with two control stations in Inchon Dock to clarify the quantity, quality and standing crop of phytoplankton from Oct. to Nov., 1976. Thirty seven species of phytoplankton, representing 18 genera, 36 species, 1 forma were taken in this research. Chaetoceros decipiens, Rhizosolenia delicatula, Hemiaulus sinensis, Chaetoceros affinis and Skeletonema costatum were the dominant species in this area during two moths. By the ecological division, the neritic species occupied 86.5% of total phytoplankton composition. Standing crop of phytoplankton represented much variation: ranging from 263 to 1, 614, 832 cells/l. The maximum happened at station 1 on November.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.117.1-117.1
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• 2011

We present the smoothness of mid-infrared sky brightness from the Japanese infrared astronomical satellite, AKARI observations. AKARI monitored the north ecliptic pole (NEP) during its cold phase with nine wavebands from 2.4 to 24 ${\mu}m$, out of which six mid-infrared bands are used in this study. Simple sinusoidal fit to the seasonal variation of the sky brightness shows that the mid-infrared brightness towards the NEP is not affected by small-scale features of the interplanetary dust cloud. We applied the power spectrum analysis to the images to search for the fluctuation of sky brightness. The fluctuation powers at 200 arcsecond are estimated to be at most $1.58{\pm}0.33\;nW\;m^{-2}sr^{-1}$ or 0.13% of the total brightness at $7{\mu}m$ and a tleast $0.64{\pm}0.11\;nW\;m^{-2}sr^{-1}$ or 0.02% at $18{\mu}m$. The residual fluctuations at a few arcminute scales at short mid-infrared wavelengths (7, 9, and 11 ${\mu}m$) are consistent with those expected from the diffuse galactic light. At long mid-infrared wavelengths (15, 18, and 24 ${\mu}m$) the measured fluctuations are comparable to or smaller than the one caused by photon noise and their sources are not identified. We conclude that the upper limit of the fluctuation in the zodiacal light is about 0.02% of the sky brightness.