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        검색결과 211

        44.
        2020.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        오렌지는 우간다에서 식량 및 영양 공급과 농촌 일자리 창출에서 매우 중요한 작목이다. 그러나 최근에 우간다 오렌지 주산지 Teso지역 농업인들은 잎과 과일의 반점병뿐만 아니라, 관개시설의 절대적 부족과 기후변화에 의한 가뭄으로 생산량 감소와 폐농하는 사례들이 발생하고 있다. 따라서 본 연구는 우간다 오렌지 생산 농가들의 생산량과 소득을 증가시키기 위하여 효과적인 반점병 및 토양수분 관리 기술을 개발하고자 농가를 대상으로 실증을 실시하였다. 1. 오렌지 반점병 방제에 효과적인 약제를 선발하기 위하여 ridomil, carbendazim, 그리고 cooper 살균제들의 단제, 교호 및 혼합 살포한 결과 Carendazim 단제 사용으로 오렌지 반점 병을 방제하였을 때 농가 생산량과 소득은 각각 55.2% 및 74.8% 증가하여 오렌지 나무 대부분 생육단계에서 가장 효과적이었다. 2. 오렌지 과수원 토양수분 관리는 외부에서 과수원으로 연결하는 빗물 유도로(trench)와 오렌지 나무 밑 수반형 빗물 저장시설(basin)을 설치한 다음 가축 배설물(manure)을 함께 처리하였을 때 농가소득이 약 2배나 증가하는 등 가장 효과가 좋았다. 3. 이러한 연구결과를 바탕으로 향후 오렌지 주산지역 농가를 대상으로 시범마을 사업으로 확대 적용할 예정이다.
        4,000원
        45.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We studied trichloroethylene (TCE) adsorption from aqueous solutions in equilibrium conditions by activated carbons (AC). They differ in raw materials, porous structure characteristics and chemical state of the surface. TCE adsorption isotherms were found to have a concave shape, which is characteristic of a sorbent—sorbate weak interaction. It can be a result from electrostatic repulsion of organic matter molecule from polar groups on carbon surface and adsorbed water molecules. The basic parameters of adsorption were calculated by the Dubinin–Radushkevich equation. We determined that for AG-OV-1 and SKD-515 in the coordinates of the Dubinin–Radushkevich equation, there are two linear plots suggesting adsorption in pores of different sizes or reorientation of adsorbate molecules on the activated carbon surface. The efficiency of TCE removal by the activated carbons was evaluated. To reduce the TCE to the maximum allowable, the lowest sorbent consumption was observed for AC with the highest values of surface area and micropore volume. However, the high cost and hydrophobicity of these adsorbents make it impractical to use them in adsorption columns with a fixed layer. We offered an adsorbent that reasonably combines extraction efficiency, ease of operation and economic feasibility.
        4,000원
        46.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effects of the number of frozen-thawed ram sperm per single and double intra-cervical artificial insemination (AI) on fertility in ewes were studied. A total of 89 non-pregnant ewes were synchronized for oestrus with two doses of 100 μg PGF2α (Cloprostenol) 9 days apart. The ewes were randomly assigned to one of four groups; D200 (n = 23; double AI with 200 × 106 sperm), S200 (n = 24; single AI with 200 × 106 sperm), D100 (n = 24; double AI with 100 × 106 sperm) and S100 (n = 18; single AI with 100 × 106 sperm). Ewes were inseminated within 12 to 18 h for single AI and, within 10 to 12 h and 16 to 18 h for double AI after the onset of oestrus. The onset of oestrus ranged from 28 to 76 h (54.33 ± 1.28 h). The high percentage (29.2%) of ewes showed oestrus between 51 to 60 h. The non-return rates were highest in group D200 (56.5%) and differed significantly (p < 0.05) from group S100 (11.1%). No ewes were pregnant in group S100, and the pregnancy rates among the remaining groups did not differ. The mean gestation period was 152.8 ± 0.5 days and no difference was observed among the groups. The lambing and multiple birth rates were 100% in group D200. The single and twin lambing was highest in group D100 (33.3%) and group D200 (83.3%), respectively. Only one triplet lambing and the highest lambing size (2.2 ± 0.2) was recorded in group D200. In conclusion, double AI with 200 × 106 sperm showed comparatively most practical for achieving high pregnancy rates and lambing performances in Bangladeshi ewes under field conditions.
        4,000원
        47.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of the current study was to compare the effects of season and breed on the reproductive performance of male and female sheep using 12 rams and 318 ewes of Assaf and Awassi breeds under the seasonal environmental condition of United Arab Emirates for two years. The blood level of testosterone hormone was measured monthly. Semen was collected twice a month from each male using artificial vagina and evaluated for volume, motility, livability, abnormality and concentration. The scrotal circumference and thickness as well as the left testicular length, width, height and volume were measured at one-month intervals. The level of testosterone in Assaf breed was significantly higher in autumn than winter and summer. The scrotal circumference and thickness as well as the left testicular length were significantly higher in Assaf breed than Awassi breed. While, left testicular width and volume were significantly higher in Awassi breed than Assaf breed. Scrotal circumference which was higher in spring and summer than in autumn and winter season in both breeds. The SCC of semen was significantly higher in autumn than in other seasons in both breeds. The sperm abnormality was significantly higher in summer than other seasons in both breeds. The livability was significantly lower in summer in both breeds. Fecundity and prolificacy were significantly higher in Assaf than Awassi breed during autumn season. Assaf breed showed the superior reproductive performance in the autumn season when compared with Awassi breed in the same season and other seasons. The Assaf breed tolerated the climatic conditions in UAE and kept the litter size of 1.72 in comparison to Awassi breed which showed litter size of 1.09. in conclusion, the results showed the superiority of Assaf over Awassi breed and offer a good model of breeding with increased fecundity and prolificacy specially in autumn season.
        4,000원
        48.
        2020.04 구독 인증기관 무료, 개인회원 유료
        홍콩의 비중국어권 유치원생들은 중국어 학습 과정 중에 많은 어려움을 겪게 된다. 개인적인 이유 외에도 교사와 학교 모두 자원, 교재, 경험 등의 부족으로 이들의 중국어 학습은 도전적 상황에 직면해있다. 최근 홍콩 평등기회위원회(香港平等機會委員會)는 중국어권 학습자와 비중국어권 학습자의 통합교육을 적극적으로 건의하였는데, 본래의 좋은 취지와는 다르게 여러 가지 새로운 문제점들이 제기되는 결과를 가져왔다. 이러한 어려움을 해결하기 위해 홍콩 경마자선기금(香港賽馬會慈善基金)과 관련 협력 기관에서는 큰 규모의 연구를 기획하고 실제 프로그램을 개발하여 비중국어권 유치원 교육을 지원하였다. 다양한 프 로그램 가운데, 본 연구는 언어 학습 이론과 효과적인 교육에 중점을 두고, 수업 현장 관찰, 수업 비디오 녹화, 교장과 교사 인터뷰, 학습자 언어 학습 평가와 같은 연구 방법을 사용하 여 연구를 진행하였다. 본 연구는 비중국어권 유아를 대상으로, 유아반에서 상위반까지의 언어학습 발달과정을 추적 하여 네 차례 언어학습 평가를 진행하였다. 학습자의 3년간의 언어 성적은 뚜렷한 성장을 보였는데, 이를 통해 학습이론과 실제 교육법 사이에 분명한 효과가 있음을 알 수 있었다. 또한 본 연구가 통합 정리한 10종의 언어학습이론은 홍콩의 중국어권 유아와 비중국어권 유아의 통합교육에 매우 적합했고, 본 연구에서 얻어진 여러 실제 사례들은 간단히 실행 가능할 뿐만 아니라 많은 자원이 투입되지 않는다는 사실도 도출해 내었다. 본 연구의 이론과 실제 성과가 학계 및 교육 실무자들에게 참고가 되기를 기대해 본다.
        6,900원
        49.
        2020.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Assisted reproductive technologies (ART) merely depend on improving the oocyte maturation and their developmental competence to produce good quality embryos. Oocyte maturation passes through long and complex molecular steps starts from the early embryonic life and ends with sperm fertilization. Oocyte developmental competence can be attained by improving the nuclear and cytoplasmic mechanisms together with some epigenetic maturation. In this review, we highlight the cornerstones of oocyte maturation on both nuclear and cytoplasmic levels. Interfering or supporting these molecular mechanisms would help in the development of novel regulating agents for reproductive performance of humans and livestock species.
        4,000원
        51.
        2019.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        While the reverberation mapping technique is the best available method for measuring black hole mass in active galactic nuclei (AGNs) beyond the local volume, this method has been mainly applied to relatively low-to-moderate luminosity AGNs at low redshift. We present the strategy of the Seoul National University AGN Monitoring Project, which aims at measuring the time delay of the Hβ line emission with respect to AGN continuum, using a sample of relatively high luminosity AGNs out to redshift z ∼ 0.5. We present simulated cross correlation results based on a number of mock light curves, in order to optimally determine monitoring duration and cadence. We describe our campaign strategy based on the simulation results and the availability of observing facilities. We present the sample selection, and the properties of the selected 100 AGNs, including the optical luminosity, expected time lag, black hole mass, and Eddington ratio.
        4,200원
        52.
        2019.07 구독 인증기관 무료, 개인회원 유료
        The research employs factor analysis, followed by a MANOVA procedure to explore relationships between fashion consumption and social media usage behavior based on data collected from 447 individuals. Findings suggest that social media usage and apparel consumption motivations interact, particularly for whom use social media for instant-self presentation.
        5,500원
        54.
        2019.07 구독 인증기관 무료, 개인회원 유료
        The global luxury travel market is in a constant state of flux, and traditional players have to adapt to the rising challenges in various areas of their business model. As new players emerge, using technology and the global reach of the Internet and social media to reach out to a discerning group of travelers, they speak to the changing expectations and behavior of international consumers. Our study will shed light on these consumption and travel patterns, on ways new disruptors in the field of luxury hospitality successfully differentiate themselves from their more traditional competitors and on the implications this will have on the business models of five-star hotels in Switzerland. While limited in scope, this study will provide insight relevant to academics and professionals in the field of luxury hospitality.
        4,000원
        57.
        2019.04 구독 인증기관·개인회원 무료
        Females of adzuki bean beetle (ABB), Callosobruchus chinensis (L.), a cosmopolitan field-to-storage pest of legumes, release sex pheromone consisting of two isomeric components, 2Z-homofarnesal and 2E-homofarnesal. Two day old virgin ABB adults were exposed to sub-lethal fumigation doses (LC25=0.0056 and LC50=0.0076 mgL-1) of phosphine (PH3) to evaluate the effects on adult longevity, fertility and sex pheromone production. Longevity (female; P < 0.001, male; P < 0.001), fecundity (P < 0.001) and sterility (P < 0.001) were significantly affected. The GC-MS for solid phase micro extraction exhibited the significant reduction of release of both of the pheromone components; 2Z-homofarnesal (P < 0.0038) and 2E-homofarnesal (P = 0.0009) when the females were exposed to LC25 dose of PH3. This study unveils the detrimental effects of PH3 fumigation on some of the biological parameters of ABB.
        59.
        2018.10 구독 인증기관·개인회원 무료
        Azuki bean beetle (ABB), Callosobruchus chinensis (L.) is a cosmopolitan field-to-storage pest of legumes. Its female sex pheromone consists of two isomeric components, 2Z-homofarnesal and 2E-homofarnesal. Two day old virgin adults were exposed to sub-lethal fumigation doses (LC25=2.80 and LC50=3.32 mgL-1) of ethyl formate (EF) to see the effects on adult longevity, fecundity, sterility and female sex pheromone production. Longevity (female; P < 0.001, male; P < 0.001), fecundity (P < 0.001) and sterility (P < 0.001) were significantly affected. The Gas Chromatography-Mass Spectrometry for solid phase micro extraction revealed that release of both of the pheromone components were not affected by LC25 dose of EF. However, the fecundity (per female/day) was significantly (P < 0.001) stimulated by the tested EF doses when the female adults were treated irrespective of the male treatment, probably revealing a hormetic effect. This study provides insight into the effect of EF fumigation on biological activities of C. chinensis.
        60.
        2018.10 구독 인증기관·개인회원 무료
        Spotted wing drosophila (SWD), Drosophila suzukii, is a serious pest of berry fruits and grapes in East-Asia and USA. SWD female oviposits eggs into the skin of ripening fruits, and the larvae dig a burrow inside the fruits. Secondary infestation by other insects and pathogens to the oviposition spots cause substantial economic damages worldwide. SWD has recently been spreading to Europe and USA, and it is becoming a global threat in terms of biosecurity. A quite useful paper has been published in Journal of Chemical Ecology in the most recent issue (Vol. 44, #10) which is titled ‘Advances in the chemical ecology of the spotted wing drosophila (Drosophila suzukii) and its applications’ written by Cloona et al. This article introduces chemical constituents from many odor sources such as fermentation, yeast, fruit, and leaf sources, and commercial lures and traps developed using these compounds. Authors said that the current food-based lures and trap technologies are not expected to be specific to SWD and thus capture large numbers of non-target drosophilids. Attractive and aversive compounds are being evaluated for monitoring, mass trapping, and for the development of attract-and-kill and push-pull techniques to manage SWD populations. (Supported by PJ011756022018, RDA)
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