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        검색결과 210

        81.
        2013.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 244,443 도체로부터 얻은 도체특성(성별, 등지방두께 및 도체중), 사육환경(자돈의 성별 분리사육, 돈사의 온도관리 유무, 돈사의 형태, 환기방식, 급수원의 종류, 음수 개선시설의 유무, 돈사의 연간 소독횟수, 돈사의 바닥형태 및 평당 사육두수), 출하방법(선별출하, 출하일령, 등지방두께의 편차 및 도체중의 편차) 및 번식특성과 자돈관리(모돈의 산차, 이유일령, 정액의 분양처 및 자돈의 품종)등의 자료를 바탕으로 돼지의 도체가격에 미치는 영향을 분석하기 위해 실시하였다. 도체특성 변수에서 암퇘지 및 거세돈이 숫퇘지보다 높은 가격을 형성하였으며(p<0.05), 등지방두께 15-29mm 및 도체중 91-95kg가 높은 도체가격을 보였다(p<0.05). 도체가격에 대한 등지방 두께 및 도체중은 도체가격 형성에 각각 90.75%와 90.23%를 차지하였다. 하지만, 사육환경, 출하방법, 번식관리는 각각의 방법별로 가격에 유의적인 차이를 보였으나, 도체가격형성에는 낮은 영향을 미쳤다. 이상의 결과 여러 가지 변수 중 등지방 두께 및 도체중이 도체가격에 큰 영향을 미친 것으로 나타났다.
        4,000원
        82.
        2013.10 구독 인증기관·개인회원 무료
        A major concern in exporting agricultural commodities is the introduction or spread of exotic quarantine pests to the new area. To prevent spread of insect pests, various phytosanitary measures are used. In this study, we compared the effect of electron beam and X-ray irradiation on development and reproduction of the two-spotted spider mite, Tetranychus urticae. Eggs, nymphs, and adults were irradiated at target doses of 50, 70, 100, 150, 200, 250, and 300 Gy with electron beam and 10, 20, 30, 50, 70, 100, 150, and 200 with X-ray irradiation. When eggs were irradiated, egg hatching was completely inhibited at 150 Gy of electron beam and 50 Gy of X-ray irradiation. When irradiated to the nymphs, emergence was not affected at all target dose in both electron beam and X-ray irradiation. Hatchability of F1 generation was significantly decreased at 100 Gy of electron beam and 70 Gy of X-ray irradiation. When irradiated to the adults, longevity did not show any differences at all target dose in both electron beam and X-ray irradiation. These results suggest that the effect of X-ray irradiation was more potential than electron beam irradiation.
        83.
        2013.10 구독 인증기관·개인회원 무료
        Riptortus pedestris (Hemiptera: Alydidae) is known to occur in barley field during spring. But, it is unlikely that R. pedestris can find host resource to reproduce in the spring season. To test this hypothesis, we assessed the reproduction of R. pedestris population collected from field from March to September. Riptortus pedestris were collected at intervals of three days from 15th of each month. Females of R. pedestris collected from trap were provided with just water in a breeding dish, and eggs laid were collected daily. Quality of R. pedestris eggs at each month was also evaluated by providing them as host resource to two egg parasitoids. The collected eggs were divided into three groups and tested for hatchability and parasitism by two egg parasitoids, respectively. As a result, R. pedestris population collected in March and April did not reproduce, and fecundity and proportion of reproduced females were the highest in August. But, neither hatchability nor parasitism rate of R. pedestris eggs show significant difference among the sampling months. In conclusion, R. pedestris starts to reproduce from May, and fecundity reaches highest on August. No change in egg quality was found among the study periods.
        84.
        2013.10 구독 인증기관·개인회원 무료
        Frankliniella occidentalis (Pergande) and Frankliniella intonsa (Trybom) (Thysanoptera: Thripidae) are sympatric thrips species infesting crops including strawberry and pepper. Recently, F. intonsa was found as a dominant species locally even though F. occidentalis has been considered as a major species in Korea. We suggested interspecific competition as a underlying mechanism for the asymmetrical abundance. Effect of the competition on adult reproduction and longevity of the two thrips species was assessed in leaf cage and microtube arena, respectively. The number of reproduced progeny was reduced by 79% for F. occidentalis and only 43% for F. intonsa in competition condition. The mean longevity was also reduced greater in F. occidentalis (by 41%) than in F. intonsa (23%). Based on these results, it is probable that interference competition exists between the two species, and F. intonsa is better competitor than F. occidentalis. Therefore, interspecific competition might affect field occurrence pattern of the two thrips species.
        85.
        2012.12 구독 인증기관 무료, 개인회원 유료
        멀티미디어의 개발에 따라 가상 영상에 대한 실사적인 색 표현이 가능해졌다. 이로 인해 영상에서 물체를 표현하기 위해 빛과 표면의 특성을 기반으로 색을 표현하는 렌더링 기법들이 개발되고 있다. 빛과 표면의 물리적인 상호작용을 모델링하는 과정에서 각각에 대한 분광 특성에 대한 정보가 정확하다면 결과영상은 정확하게 표현할 수 있다. 그러나 기존의 렌더링 응용은 단순한 RGB 기반 3차원을 이용하여 벡터의 성분별 합과 곱으로 빛과 표면의 분광 특성을 표현하고 상호작용을 모델링하기 때문에 실제적인빛-표면 상호 작용과 수학적인 연산이 일치하지 않는다. 이를 해결하기 위해 본 논문에서는 새로운 특성함수 기반의 기저함수를 이용하여 단순한 연산으로 빛-표면 상호작용을 계산할 수 있는 표면 반사율 모 델 기법을 제안한다.
        4,000원
        87.
        2012.05 구독 인증기관·개인회원 무료
        Insecticidal susceptibilities of 16 registered insecticides on each developmental stages of Phthorimaea operculella were investigated and further examined the contact, oral and residual toxicities after chosen from insecticides showing good effect. Mortality, longevity and effect on reproduction of 16 insecticides to P. operculella adults were also investigated. To the eggs and pupae, only spinosad showed 71.1% inhibition rate of egg hatch and 66.7% inhibition rate of emergence. To the 3rd nymphs, fenitrothion (LC50 336.6 ppm), esfenvalerate (LC50 8.6 ppm), ethofenprox (LC50 35.7 ppm), and emamectin benzoate (LC50 0.05 ppm) showed oral toxicity over 90% and esfenvalerate (LC50 0.87 ppm), ethofenprox (LC50 16.5 ppm), emamectin benzoate (LC50 0.53 ppm), and spinosad (LC50 2.48 ppm) showed the contact toxicity over 90%. To the adults, mortalities of insecticides were showed as below: deltamethrin and spinosad showed perfect mortality 48 h after treatment; esfenvalerate, ethofenprox, and thiamethoxam showed 40 - 60% mortalities; but the others are not showed any effect. Fecundities of female adults were inhibited by esfenvalerate, emamectin benzoate, and dinotefuran, compare to that of the control, but there were no statistical differences to that of ethofenprox, benfuracarb, thiamethoxam, clothianidin, and diflubenzuron. Adult longevity was showed no difference compare to that of the control. Residual effect of emamectin benzoate showed perfect insecticidal activity at 14 days after treatment and the next ethofenprox showed over 90% at 7 days after treatment.
        88.
        2012.05 구독 인증기관·개인회원 무료
        Male pheromone production and female reproduction of R.pedestris were evaluated on two different kinds of foods; sweet (non-astringent) persimmon and soybean. Male adults fed on soybean produced all the four pheromone components, (E)-2-hexenyl (Z)-3-hexenoate, (E)-2-hexenyl (E)-2-hexenoate, tetradecyl isobutyrate (C14iBu), octadecyl isobutyrate (C18iBu), whereas those fed on sweet persimmon did not produce C14iBu which is a key component in the function of the pheromone, and C18iBu. Female adults fed on soybean produced eggs, however, those fed on sweet persimmon did not at all. From these results, we concluded that host resource greatly affects the chemical communication and reproduction of both male and female of R.pedestris, and that sweet persimmon is not a proper food for its completion of life cycle.
        89.
        2012.05 구독 인증기관·개인회원 무료
        Sound treatments have been considered as a non-chemical insect pest control technique. Different frequency and intensity sounds were applied to immune and adult stages to screen any stress sounds to alter physiological processes. At 95 dB, 5,000 Hz and 30,000 Hz were selected to be stress sounds in audible and inaudible sound ranges, respectively. Both stress sounds significantly inhibited larval and pupal development. In biochemical analyses, lipid and sugar levels in plasma signigicantly increased in response to the stress sound treatments. Moreover, a digestive phospholipase A2 enzyme activity in midgut was significantly reduced. In adult stage, ultrasound treatment significantly inhibited mating behavior, which resulted in a reduced fecundity. These stress sounds altered gene expressions of stress-related genes, such as heat-shock proteins and apolipophorin III. This study suggests that extreme sounds play a role in physiological stress factors in S. exigua by altering developmental and reproductive processes.
        90.
        2012.03 구독 인증기관 무료, 개인회원 유료
        This study was carried out to investigate artificial insemination (AI) failure status and frozen semen characteristics in Korean proven bulls‘ number (KPN) semen used for AI of Hanwoo cows in Gangwon East region (Gangneung, Donghae, Taebaek, Samcheok, Sokcho, Yangyang, Goseong). Among semen used for AI, AI failure rate showed lowest at KPN506 (27.6%), whereas highest at KPN593 (77.2%). Correlations of AI failure in between Korean proven bulls semen and cows was 0.2941, which means that AI failure rate of Korean proven bulls semen may have respectable effect on reproduction of Hanwoo cow. In addition, present study was conducted to investigate spermatozoal viability rate, ruptured acrosome rate and active mitochondria in frozen Korean proven bulls semen with flow cytometry. The semen of KPN593 showed significantly (p<0.05) higher viability rate in KPN593 (30.49%) than that in KPN637 (37.34%). Furthermore, percentage of ruptured acrosome was lower in KPN637 as 21.37% than in KPN637 (21.37%), but it was not statistically significant. In conclusion, these results indicate that choice of Korean proven bulls semen may correlate positively with conception rate in Hanwoo cow. Therefore, KPN with high AI failure rate might be avoid to increase conception rate and characteristics of frozen semen might be evaluated before its use for AI.
        4,000원
        91.
        2012.03 구독 인증기관 무료, 개인회원 유료
        CRT와 달리 PDP (Plasmadisplaypanel)에서의 휘도는 입력 계조에 따라 선형적으로 증가한다. 이와같은 휘도 특성으로 인해 PDP에서는 역감마 보정을 수행하여야 한다. 저계조에서 CRT의 휘도 증가율은PDP와 비교하여 매우 낮다. 따라서, 역감마 보정 후 저계조 영역에서 표시 가능한 휘도의 개수가 감소하게 되어 의사윤곽이 발생한다. 이와 같은 문제점의 해결을 위해 디더링 또는 오차확산이 사용되고 있다. 그러나, PDP의 저계조에서 이웃한 두계조의 휘도 차가 인간 시각이 인지 가능할 정도로 크기 때문에 디더링 또는 오차확산의 결과에서 소수화소들이 isolated 도트로 인지된다. 본 논문에서는 시공간적인 문턱값 변조를 통해 PDP에서의 저계조 재현 성능을 향상시키는 방법을 제안한다.
        4,300원
        92.
        2011.10 구독 인증기관·개인회원 무료
        The effects of electron beam irradiation on development and reproduction of Spodoptera litura were examined. Eggs, larvae, pupae, and adults were irradiated at target doses of 30, 50, 100, 150, 200, and 250 Gy. When eggs were irradiated with 100 Gy, egg hatching was perfectly inhibited. When irradiated to the larvae, pupation was inhibited at 100 Gy and larval period was delayed. When irradiated to the pupae, emergence was inhibited at 100 Gy and above. When irradiated to the adults, longevity and fecundity did not show any differences. However, egg hatching was strongly decreased at 100 Gy and above. Also, electron beam irradiation was not induced the instantaneous death of S. litura. The levels of DNA damage in S. litura adults were evaluated using the alkaline comet assay. Our results indicate that electron beam irradiation increased levels of DNA damage. These results suggest that electron beam irradiation induced abnormal development and reproduction by DNA damage in S. litura.
        93.
        2011.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4,000원
        94.
        2011.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Maturation and spawning of the Shotted halibut, Eopsetta grigorjewi was investigated based on the samples captured in South Korean waters from January 2008 to December 2009. Gonadosomatic index began to increase in December, and reached maximum between January to March. After spawning it began to decrease from May. Reproductive season was estimated to January-April, with peak in February. Fecundity was proportional to the size of the female, with the clutch size varying from 170,000 eggs in the smallest female (total length, 28.9cm) to 1,300,000 eggs in the largest (total length, 41.5cm). Size at 50% sexual maturity (TL50), determined from mature females, was 28.8cm. Annual reproductive cycles of this species could be divided into six successive stages; immature stage (May-October), nucleolus stage (November-January), yolk vesicle stage (January-February), vitellogenic and ripe stage (January-April) and spent stage (April-May).
        4,000원
        95.
        2011.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study was to analyze the reproduction and breeding status of 1655 Hanwoo (Korean cattle) cows raised in Gangwon East area (Gangneung, Taebaek, Donghae, Yangyang, Samcheok, Sokcho, and Goseong). The average age in months and the parity of Hanwoo was 43.6 and 1.7 respectively. Registration status of the cows were 42.0% (pedigree), 30.2% advanced), 20.0% (fundamental), and 4.0% (non-registry). Korean proven bull's number (KPN) 517 and KPN 588 were preferred 25.8%, 16.2% respectively for artificial insemination (AI) of the cows. Appearance rate of over 1st meat quality grade in the offsprings obtained from AI of top 6 KPNs was 90% which was above national average (slaughters only 77.81%, total 63.12). Results indicated genetic influence the KPN for meat quality grade of their offspring. Strong correleation between AI failure rate of mother cows and their offspring cows has been observed. KPN information, meat quality grade, and AI failure percentage would be quite useful factors to understand their relationship in further improvement of Hanwoo in Gangwon East area.
        4,000원
        97.
        2011.05 구독 인증기관·개인회원 무료
        This study was performed to investigate the effect of flonicamid and thiamethoxam treated at sublethal concentration (LC10, LC30) on development period, adult longevity and fecundity and the feeding behaviour of Myzus persicae adult. Developmental period of M. Persicae nymph took 5.9 days in LC10, and 6.1 days in LC30 in both insecticides, comparing with control (5.7 days), it showed longer than those of the control, but there was no significance. Adult longevity treated at LC10 and LC30 of flonicamid was showed 13.2 and 13.7 days, respectively, and LC10 of thiamethoxam was examined as 14.7 days, it showed longer than control of 11.6 days. Mean daily fecundity exhibited higher in LC10 (3.1) and LC30 (3.1) of flonicamid than that of control (2.5), but thiamethoxam are not. Total fecundity exhibited higher in LC10 (41.8) and LC30 (43.0) of flonicamid, in LC10 (42.1) of thiamethoxam than that of control (29.5). Feeding behavior was examined using EPG (electrical penetration graph). EPG data indicated that flonicamid and thiamethoxam increased the duration of non-probing periods and decreased the duration of phloem ingestion.
        98.
        2011.05 구독 인증기관·개인회원 무료
        Pine wood nematode (PWN), Bursaphelenchus xylophilus is associated with the pine wilt disease and transmitted by pine sawyer, Monochamus alternatus. Because pine sawyer has one-year life cycle, one natural infection of PWN is occurred a year. Therefore, artificial propagation method of PWN is needed to improve experiment associated with PWN. In this study, effect of diameter, paraffin sealing of twig and dosage on pine wood nematode reproduction in Japanese black pine, Pinus thunbergii. PWN reproduction was compared in twigs of P. thunbergii and P. densiflora. Numbers of reproduced PWN were higher with decreasing diameter of twig. Distance (5 and 10 cm) from inoculation site of PWN did not influence reproduction of PWN. Reproduced numbers of PWN were higher in the paraffin-sealing twig than non-sealing twig. Dosage of PWN influenced reproduction of PWN. Reproduction rate was the highest at the rate of 10 IJs (13.7 and 61.1-fold increasing in P. densiflora and P. thunbergii, respectively 30 days later) whereas lowest at the rate of 1000 Ijs (1.1 and 0.7-fold increasing in P. densiflora and P. thunbergii, respectively 30 days later). Numbers of reproduced PWN were more in P. thunbergii than P. densiflora.
        100.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Four major agricultural insect pests, Bemisia tabaci, Myzus persicae, Plutella xylostella and Tetranychus urticae, were irradiated with 30, 50, 70, or 100 Gy electron-beam. Longevity, egg hatching, emergence, and fecundity of the test insects were measured. Hatchability of B. tabaci, P. xylostella and T. urticae declined with increasing irradiation doses, and all B. tabaci and T. urticae eggs were dead at 100 Gy. When eggs of B. tabaci, P. xylostella and T. urticae were irradiated, hatch was inhibited. B. tabaci adults grown from 70 Gy irradiated eggs did not lay eggs. Fecundity of P. xylostella from the 100 Gy irradiated eggs decreased. When B. tabaci, P. xylostella, M. persicae and T. urticae nymphs/larvae were irradiated, the results were similar as those of the hatched eggs. When P. xylostella pupae were irradiated with 100 Gy, fecundity of emerged adults decreased and no eggs hatched. When B. tabaci, P. xylostella, M. persicae and T. urticae adults were irradiated with 70 and 100 Gy, fecundity decreased and egg hatch of B. tabaci was inhibited. However, the longevity of adults did not change and electron-beam irradiation of all developmental stages had no effect on the longevity of adults.
        4,000원
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