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        검색결과 1,263

        581.
        2012.10 구독 인증기관·개인회원 무료
        In the case of one standard-mum polyvinyl house, the density of F. occidentalis reached its peak in early June and decreased after the chemical control, which was carried out periodically. In the case of another standard-mum polyvinyl house, the density of F. occidentalis increased continuously in spite of the periodical chemical control after planting. In both polyvinyl houses, the density of F. occidentalis began to increase mid-May. The numbers of F. occidentalis collected on a tray with wet paper by heating the flowers of pink, white, and yellow Chrysanthemum standard mums were 18.4, 56.6, and 52.6 after flowering, but in the case of the leaves, the numbers were 7.8, 16.6, and 15.4. Also, the numbers of F. occidentalis collected on a tray with wet paper by heating the buds of pink, white, and yellow Chrysanthemum standard mums were 15.2, 45.8, and 41.6, but in the case of the leaves, the numbers were 2, 8.8 and 3.4. In the Y-tube olfactometer test, the frequency of F. occidentalis’ visits to one side arm of the Y-tube olfactometer was higher in the odor cue of the white flower than of the yellow, red, and violet flowers, but in the other combinations without white flowers, the frequency was higher in the odor cue of the violet and red flowers than of the yellow flowers. In the case of the four-choice olfactometer test, in the same visual cues as the odor cues of the pot mum flowers, the frequency of F. occidentalis was higher in the yellow flower than in the other flowers (white, red, and violet) in all the observation times (10, 15, and 20 minutes). In the case of the visual cues with disturbed odor cues, F. occidentalis preferred the yellow color to the other colors in all the observation times (10, 20, and 40 minutes). F. occidentalis preferred the white color to the other colors when the same odor cues as the flower color were provided, but the odor cue of the yellow flower was provided only without the color cue.
        582.
        2012.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In crystalline solar cells, the substrate itself constitutes a large portion of the fabrication cost as it is derived fromsemiconductor ingots grown in costly high temperature processes. Thinner wafer substrates allow some cost saving as morewafers can be sliced from a given ingot, although technological limitations in slicing or sawing of wafers off an ingot, as wellas the physical strength of the sliced wafers, put a lower limit on the substrate thickness. Complementary to these economicaland techno-physical points of view, a device operation point of view of the substrate thickness would be useful. With this inmind, BC-BJ Si and GaAs solar cells are compared one to one by means of the Medici device simulation, with a particularemphasis on the substrate thickness. Under ideal conditions of 0.6µm photons entering the 10µm-wide BC-BJ solar cells atthe normal incident angle (θ=90o), GaAs is about 2.3 times more efficient than Si in terms of peak cell power output:42.3mW·cm−2 vs. 18.2mW·cm−2. This strong performance of GaAs, though only under ideal conditions, gives a strongindication that this material could stand competitively against Si, despite its known high material and process costs. Within thelimitation of the minority carrier recombination lifetime value of 5×10−5 sec used in the device simulation, the solar cell poweris known to be only weakly dependent on the substrate thickness, particularly under about 100µm, for both Si and GaAs.Though the optimum substrate thickness is about 100µm or less, the reduction in the power output is less than 10% from thepeak values even when the substrate thickness is increased to 190µm. Thus, for crystalline Si and GaAs with a relatively longrecombination lifetime, extra efforts to be spent on thinning the substrate should be weighed against the expected actual gainin the solar cell output power.
        3,000원
        583.
        2012.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Bovine brucellosis causes abortion and infertility. The authors conducted this study in order to determine pathological lesions of Korean native cows and fetuses who received experimental vaccination with Brucella abortus RB51 and were challenged with Brucella abortus 2308. Gross and histopathological lesions in endometrium and placenta were observed in cows of the vaccinated group. Twenty-five percent of pregnant cattle in the vaccinated group showed endometritis and placentitis, which was three times lower, compared with the non-vaccinated group. The pathological lesions in the uterus and placenta in both groups were consistent with previous reports. Therefore, vaccination in heifers using Brucella abortus RB51 may not provide adequate protection against infection with Brucella abortus virulent strain.
        4,000원
        584.
        2012.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was performed to compare the muscle activity of lumbar stabilizers between stoop and semi-squat lifting techniques at different lifting loads. Twenty healthy subjects (9 males, 11 females) were recruited for this study. Muscle activity of external obliques (EO), internal obliques (IO) and lumbar multifidus (LM) muscle was measured by surface electromyography during stoop and semi-squat lifting at different lifting loads (10%, 20%, and 30% of the subject's body weight). A one-way repeated measure ANOVA was applied. The results showed that EMG activity of EO was significantly increased with a load of 30% of body weight compared to 10% and 20% of body weight in both lifting techniques (p<.05). Muscle activity of LM was significantly increased in 20% compared to 10% and 30% compared to 10% of subject's body weight in stoop lifting and the muscle activity of LM was significantly increased in 20% compared to 10%, 30% compared to 20%, and 30% compared to 10% of the subject's body weight in semi-squat lifting (p<.05). However, there was no significant difference in activity of IO according to lifting loads in both lifting techniques. There were no significant differences in muscle activity of EO, IO, and LM between stoop and semi-squat technique (p>.05). Therefore, the results of this study suggested that the EO can contribute to increase the lumbar stability during stoop and semi-squat lifting at 30% of body weight rather than at lower loads, and the LM seems to act as counteractor to imposed loads during stoop and semi-squat lifting with increasing loads.
        4,000원
        585.
        2012.06 구독 인증기관 무료, 개인회원 유료
        This study was conducted in order to investigate the effects of Acer tegmentosum Maxim. extract (ATE) in prevention of liver injury. After oral administration of ATE to SD rats, liver injuries were induced by treatment with CCl4, galactosamine, or ethionine. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), triglyceride, and cholesterols in blood were used as indicators of liver damage. When acute hepatitis was induced by CCl4 or galactosamine, ATE-fed rats showed a lower level of AST and ALT in plasma than ATE-unfed rats. In the case of ethionine-induced fatty liver, triglyceride levels in plasma were reduced in ATE-fed rats, compared with ATE-unfed rats. These results indicate that Acer tegmentosum Maxim. extract protected against hepatic failure.
        4,000원
        586.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fish communities in river networks provide significant ecosystem services that will likely decline under future land use and climate change. We developed a model that simulates the consequences to multiple populations of one or more fish species-a metacommunity- from multiple stressors across a river network. The model is spatiallyexplicit and age-structured, with three components: habitat suitability; population dynamics, including species interactions; and movement across a spatial network. Although this model is simple, it can form the basis of fisheries assessments and may be incorporated into an integrated modeling system for watershed management and prediction.
        4,000원
        587.
        2012.06 구독 인증기관·개인회원 무료
        today's dairy production management systems, reproductive efficiency affects the income of any farm by influencing overall milk production, genetic gain, amount of replacement heifers, and wise cullling decisions. Nutrition, management, and genetics play a major role achieving this maximum herd-reproductive performance. Several reports using trace minerals on the diet of cattle have shown reproductive effects. The main justification for using blocks, to provide deficient nutrients is, therefore, their convenience for packaging, storage, transport and ease of feeding. Dairy cattle are annually exposed to prolonged periods of elevated humidity and heat which reduce feed intake and reproductive performance. The objectives of the present study were to evaluate the effects of mineral on reproductive performance of dairy cows during Summer. The experimental group of cows had access ad libitum to the mineral lick in the following composition : Zn, Fe, Mn, Cu, I, Co, Se. Environmental heat load was described using the THI (temperature humidity index) because thermoregulation in cows is affected by both Temp and RH. The THI was calculated: THI=(0.8×Temp)+[RH×(Temp— 14.4)]+ 46.4. All cows were monitored for estrus twice daily in the morning and late afternoon. And any animal found in estrus was artificially inseminated. Pregnancy diagnosis was performed via ultrasonography at 45 to 70 d after insemination. The visitation and intake of mineral were higher with the maximum THI. The mean intake of mineral block was 23.1 kg in Summer and 17.7 kg in other seasons. The reproductive performance was considerably improved by mineral supplementation. The factors influencing consumption of mineral mixtures include: soil fertility and forage type, available energy and protein, individual requirements, salt content of the water, palatability of mineral mixture, availability of fresh minerals and physical form of minerals. These results show that minerals have a great impact on animal's reproductive physiology.
        588.
        2012.06 구독 인증기관·개인회원 무료
        Microtubule-associated protein 1B (MAP1B), a member of MAP1 family, plays a key role in the brain development. MAP1B binds to many kinds of proteins directly or indirectly. In our previous studies, MAP1B and glyceraldehydes 3-phosphate dehydrogenase (GAPDH) were down-regulated in bovine follicular cystic follicles (FCF). This study was performed to examine interaction between MAP1B and GAPDH in bovine follicles using immunoprecipitation (IP) with western blot analysis and immunohistochemisty. MAP1B and GAPDH mRNA expression levels were down-regulated in bovine FCFs. Consistent with the semi-quantitative PCR data, their protein expressions were also down-regulated in FCFs. IP data showed that MAP1B bound to GAPDH in normal follicles, but their binding was absent in FCFs, suggesting that these data might be resulted from a low level of MAP1B and/or GAPDH expression. These results suggest that GAPDH does not as always function as a loading control in bovine follicles.
        589.
        2012.05 구독 인증기관·개인회원 무료
        In haplodiploid sex determination, females are sexually reproduced from fertilized diploid eggs, and males from unfertilized haploid eggs. Haplodiploid sex determination seems simple in that sex depends simply on the ploid level. However, the underlying genetic mechanisms are thought to be much more complicated than expected. Among them, a powerful proposed mechanism is genomic imprinting. All epigenetic on-off systems require target genes, unless the systems target histone proteins on chromosomes. For Hymenoptera, a good candidate target gene in terms of sex determination is known either as feminizer (fem) or transformer (tra) in many insects. These two genes are essential for expressing femaleness. In most Hymenopteran insects, the maternal tra seems to be methylated and consequently not expressed, while the paternally derived tra gene is not methylated. Therefore, a fertilized egg with the paternally derived active tra gene will develop into a functional female. Like all Hymenoptera, ants (Formicidae) have haplodiploid sex determination. In Vollenhovia emeryi, however, queens are produced clonally while workers derive from fertilized eggs. Males are haploid, likewise deriving from fertilized eggs, but only after selective elimination of their maternal genome. Under the conventional genomic imprinting model, we would have expected that the opposite pattern of what is observed in others. Here we present extraordinary sex determination and suggest our hypothesis about genomic imprinting pattern in V. emeryi
        590.
        2012.05 구독 인증기관·개인회원 무료
        Vollenhovia emeryi ant is distinguished by its wing morphology; short winged (SW) and long winged (LW). Its reproduction shows a bizarre genetic caste system distinct from other social hymenopteran insects. Unfertilized eggs undergo genome duplication and develop into clonal gynes. Fertilized eggs develop either into workers or males. The fate of the fertilized eggs is determined whether maternal genome loss (MGL) takes place after fertilization. Eggs with MGL become haploid males with only paternal half of the genome. Without MGL, the eggs become workers with maternal and paternal half of the genome. In this research, we analysed 5 nuclear genes of SW and LW individual ants. Among them, two genes from an SW male are identical to those of LW, and one gene from the SW male seems a variant of LW. The result indicates that SW males are derived from LW colonies. From the genetic relatedness point of view individuals in the same castes are genetically identical. On the other hand, between workers and two reproductives, the relatedness is asymmetrical and there is even no gene sharing between gynes and males. The conventional genetic relatedness by Hamilton is revised under this condition.
        591.
        2012.05 구독 인증기관·개인회원 무료
        The ant species, Vollenhovia emeryi, is distributed in Far East. The species can be divided into two major groups by their wing morphology of reproductives: short-winged and long-winged. A nationwide survey of the species was conducted for analyzing the mitochondrial haplotype diversity and genetic population structure. We collected 91 samples from 40 locations. A total of the 1239 bp partial COI (cytochrome C oxidase 1) region was used for the analyses. We found the total of 21 haplotypes. The mitochondrial haplotypes may correspond to the wing morphology. The genetic population structure examined potential geographic barriers of gene flow such as distance, mountains, rivers and plains which are non-mountain areas to prevent dispersal through mountain range. The result implied that no barriers considered in this study affected differently gene flow. Therefore, the behavioral characteristics of the ant may be the causal constraint of its genetic exchange.
        594.
        2012.03 구독 인증기관 무료, 개인회원 유료
        A 40-year-old male was admitted with dry cough of two months’ duration. Radiologic examination revealed an endobronchial mass obstructing the right middle lobar bronchus and poststenotic pneumonia. Despite failure in bronchoscopic diagnosis, due to suspected malignancy and difficulty for bronchoscopic resection, we performed a right middle lobectomy. The histopathological diagnosis was a lipomatous hamartoma, which was exophytic and endobronchial. We report on a rare surgical case of endobronchial lipomatous hamartoma which had occlusive and exophytic growth across the bronchial wall.
        3,000원
        596.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국화과(Compositae)는 현화식물 중 세계에서 가장 넓게 분포하고, 쌍자엽식물 중 가장 진화된 식물분류군이며, 우리나라에는 약 300여종이 존재하는 것으로 알려져 있다. 구절초, 감국, 쑥, 쑥갓, 개미취, 참취, 곰취 등 국화과 식물들은 예로부터 민간에서 약용 및 식용 소재로써 다양하게 사용되어왔다. 본 연구는 국화 및 국화근연종 유용유전자원 선발을 통하여 육종 소재를 확대하고, 중간모본 및 신품종 육성기반을 구축하고자 DNA 마커시스템의 개발을 위해 수행되었다. 1. 화단국인 Smileball(Dendranthema grandiflorum) 품종을 사용하여 SSR-enriched library를 작성하였고, GS FLX 분석을 통해 18.83Mbp의 염기서열 결과를 얻었으며, read의 평균 길이는 280.06bp로 나타났다. 2. 단순반복염기서열(SSR) 부위를 포함하는 26,780개 clones 중 di-nucleotide motifs가 16,375개(61.5%)로 우세하였고, trinucleotide motifs(6,616개, 24.8%), tetra-nucleotide motifs(1,674개, 6.3%), penta-nucleotide motifs(1,283개, 4.8%), hexa-nucleotide motifs(693개, 2.6%) 순으로 나타났다. 3. 얻어진 di-nucleotide motifs들 중에서는, AC/CA class가 93.5%로 대부분이었고, tri-nucleotide motifs에서는 AAC class가 50.5%, tetra-nucleotide motifs는 ACGT class가 43.6%이고, pentanucleotide motif에서는 AACGT class 27.2%이며, hexa-nucleotide motif에서는 ACGATG class 21.8%였다. 4. 얻어진 염기서열 결과를 토대로 다양한 motif를 갖는 100개의 SSR 마커를 제작하였고, 차후 이를 활용하여 국화 유전자원의 다형성 및 유전자형 분석을 통해 분자유전학적 다양성 및 집단의 구조분석이 가능하고, 국화의 분자육종기반 구축을 위한 유용한 도구가 될 것 이다.
        4,000원
        597.
        2011.12 구독 인증기관 무료, 개인회원 유료
        The goal of this study is to determine, based on survey results, the underlying factors that affect the intention of the farmers who have not adopted the Hazard Analysis and Critical Control Points (HACCP) system for the rearing phase of pig production to adopt this system in the future. The research model for this study was con structed based on strategic contingency theory, the theory of the diffusion of innovation, and the technology acceptance model (TAM). Using structural equation modeling with partial least squares (PLS), this study analyzes the effects of the intensity of competition, the environmental uncertainty, the innovativeness and self-efficacy of the individual farmers, and the impact of the credibility of the Agricultural Technology Service Center (ATSC), which acts as the principal agent of technology dissemination and as a leader of change, on the perceived usefulness of technology and the farmers’ intention to adopt the system. The results of the analysis are as follows. First, with regard to the underlying factors affecting the intention to adopt the new system, the intensity of competition within the industry and the institutional credibility of the ATSC were inferred to underlie the perceived usefulness. Second, institutional credibility has a positive impact on the perceived usefulness of the system, and the perceived usefulness, in turn, has a positive impact on the intention to adopt. The perceived ease of use also has a positive impact on the intention to adopt. Because the factor that has the biggest impact on the intention of a farm to adopt is the credibility of the ATSC, it is crucial for extension organizations, such as the ATSC, to make greater efforts to promote the expansion of the HACCP system. Because farmers feel that the implementation of the HACCP system is an instrumental strategy for coping with the high intensity of competition within the industry, they attempt to gain a competitive edge through the production of safe livestock products.
        5,500원
        598.
        2011.12 구독 인증기관 무료, 개인회원 유료
        Australian teacher training universities continuously aspire to translate contemporary teacher education research findings into viable classroom teaching practice. However, much seems to be lost in the “translation.” While Australian teachers are considered to be amongst the best in the world, their reputation belies an incompatibility between modern teaching techniques and traditional approaches such as transmission and behaviorism. This paper will discuss current initiatives by the Australian Government to transform what is considered an already “quality” education system into something “better” with a newly developed national curriculum. Expectations to be placed upon Australian teachers in achieving mandates within the new national standardized curriculum will be explored.
        4,000원
        599.
        2011.12 구독 인증기관 무료, 개인회원 유료
        Peru is South America’s third largest country and enjoys an enormous amount of natural resources. However, However, very few business studies on Peruvian agriculture have been presented. The objectives of this study are to introduce the general status of Peruvian agriculture to Korean business circles and to promote agricultural business opportunities in Korea and Peru. Secondary data related to Peruvian agriculture are collected and analyzed to understand the current situation of Peruvian agriculture and to suggest an outlook for business opportunities. Findings show that Peru will be a lucrative market for Korean agri-business to target in the near future and it is time for a proactive advance in agriculture by Korean business.
        4,900원