검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 745

        183.
        2013.10 구독 인증기관·개인회원 무료
        Withthe increasing trend of global trades and protection of agro-ecosystem in importing and exporting countries against quarantine pest, quarantine and pre-shipment(QPS) fumigation in perishable commodities is now more important to maintain postharvest quality until delivering to end user not just eradiation of quarantine pest. However, there are limited use of MB fumigation on export fruits and vegetables due to phytotoxic damages of fumigated one. VapormateTM, alternative to methyl bromide(MB), a gas formulation of ethyl formate(EF) with carbon dioxide, is commercially in use for imported fruits fumigation such as bananas and lemon. Herein, based on previous preliminary studies, scale-up and commercial scale fumigation of ethyl formate is presented for promising export paprika and tomato. Efficacy of ethyl formate was described in terms of concentration × time (CT) products to Myzus persicae for paprika and Bemisia tabaci for tomato.
        184.
        2013.10 구독 인증기관·개인회원 무료
        Since Montreal protocol in1989 designated MB(methyl bromide) as ozone depleting chemicals, IPPC(International Plant Protection Convention) has adopted replacing the MB with alternative chemical and reducing the rate of MB use in plant quarantine in 2008. Pineapples are one of the most frequently fumigated imported fruit with MB in Korea. However, there was no technically available replacement. Therefore, we evaluated phosphine(PH3) fumigation as alternative to MB in applying pineapples. In the preliminary test, PH3 gas in 12L desicators to calculate ranged to 0.1 from 2g/m3 was tested at 2 and 24hr exposure to target pest, citrus mealy bug(CMB, Planococcus citri). All different of stage of CMB was shown 100% mortality when 2g/m3 of PH3 applied for 24hrs at 8℃. To confirm studies designed in 0.5m3 fumigation chamber, all egg, nymph and adult stages of CMB was killed completely and there wasn’t any phytotoxic and quality damages on pineapples for 2 weeks post-fumigation periods at 8℃. In terms of commercial use, further commercial research will need to be carry out in cooperation with importers and fumigators.
        185.
        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.
        186.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Chrysanthemum stunt viroid (CSVd) is a serious pathogen affecting chrysanthemum that has caused significant economic losses to Chrysanthemum flower production worldwide. Control of CSVd disease is difficult due to its contagious nature and long latent period in the field. As chrysanthemum is most often produced by implanting seedlings, it is necessary to diagnose CSVd infection before cultivation. In this study, we screened CSVd infection in seedlings from 30 varieties including 5 domestic, 6 Japanese, and 19 European varieties. Molecular diagnosis of the combination of RT-PCR and nested PCR showed that CSVd was not detected by the first RT-PCR but detected by the second nested PCR analysis in 10 varieties, including 1 domestic, 2 Japanese, and 7 European varieties. Further comparison of 10 identified CSVd nucleotide sequences showed that those are highly conserved (99-100%) and the most similar to an isolate (AB006737) identified in Hokkaido, Japan. Our study suggests that the combination of RT-PCR and nested PCR analysis is successful for the CSVd diagnosis of seedlings and the molecular diagnosis is necessary to prevent the introduction and propagation of viroid disease into the fields.
        4,000원
        187.
        2013.04 구독 인증기관·개인회원 무료
        The body and head lice (Pediculus humanus humanus and Pediculus humanus capitis, respectively) are hematophagous ectoparasites of humans and only the body louse between two is known to transmit three bacterial diseases through its feces. The proliferation profiles of Bartonella quintana, the causative agent of trench fever, inside the louse body and its excretion patterns were investigated in the two louse subspecies following oral challenge with B. quintana-infected blood meal. The initial density of B. quintana was sustained inside head lice without any noticeable proliferation for the entire period after infection. In contrast, B. quintana proliferated rapidly inside body lice and the maximum density reached at 10 days post-infection. The numbers of bacteria detected in feces from infected lice were almost the same and steadily decreased over time in both body and head lice. Nevertheless, the viability of the bacteria, as determined by fluorescence, was significantly higher in body louse feces, especially at 1 day post-infection and this tendency lasted for 11 days. These findings suggest that excretion of feces containing more viable B. quintana that is proliferated inside body lice following ingestion of infected blood meal is responsible for the higher vector competence of body lice.
        189.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Alpha-tocopherol as an antioxidant acts in preservation of chilled semen by preserving cell membrane damage from lipid peroxidation. Optimum concentrations of α-tocopherol in egg yolk-citrate (EYC) extender need to be studied in crossbred bull’s semen. Different concentrations of α-tocopherol viz. 0, 1, 2, 4 and 6mg per ml of extender were used. Semen was collected once a week from four bulls used to regular collection, aged 4 to 7 years, weighing 320 to 450 kg, and with body condition score 4 to 4.5 and scrotal circumference 23 to 32 cm. Semen was evaluated routinely and sperm morphology was viewed under light microscope at ×1,000 magnification after fixing with buffered formal saline. Over 90% had normal head, acrosome, mid-piece and tail. Semen was diluted with egg-yolk-citrate extender to produce 15×106 spermatozoa/ml and 0, 1, 2, 4 and 6 mg/ml α-tocopherol were added. The semens amples were kept at 8℃. Sperm motility and viability were examined daily up to 5 days under light microscopy at ×200 magnification. Sperm viability was acceptable (≥40%) up to the 4th day with all concentrations of α-tocopherol and up to the 5th day with 2 mg/ml α-tocopherol. Sperm motility was acceptable (≥40%) up to the 3rd day irrespective of α-tocopherol concentration, and up to the 4th day with 2 mg/ml α-tocopherol. It is suggested that the lifespan of chilled semen may be extended up to 4 days by adding 2mg/ml α-tocopherol.
        4,000원
        192.
        2012.10 구독 인증기관·개인회원 무료
        Frankliniella occidentalis Pergande and F. intonsa Trybom (Thysanoptera: Thripidae) are polyphagous insect pests on numerous crops. These two species reduce the crop production in two ways: by sucking sap from the plant parts and by serving as vectors for tospoviruses. In this study, we tried to confirm the previous observation of F. intonsa dominance on certain crops during recent years. Thrips populations were examined on greenhouse strawberry by installing circular yellow sticky cards with black background and on field pepper by destructive sampling of pepper flowers during season of 2012 in Songcheon, Andong. Eighty two to 92% and 3-5% of thrips collected from the both crops were F. intonsa and F. occidentalis respectively. Frankliniella. intonsa was 4-8 times more abundant than F. occidentalis in sticky cards and on pepper flowers. In conclusion, asymmetrical dominance of F. intonsa was found both in strawberry and pepper plant as we found in past on those crops. Underlying reasons such as interspecific competition and climate change were discussed.
        193.
        2012.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We will report our recent study on the properties of more than 1,600 galaxies detected by the AKARI All-Sky Survey with physical quantities based on optical and 21-cm observations, to understand the physics determining the infrared spectral energy distribution (Totani et al., 2011). We discover a tight linear correlation for normal star-forming galaxies between the radiation field strength of dust heating (corresponding to dust temperature) and the galactic-scale infrared radiation field, LTIR/R2 . This is the tightest correlation of dust temperature ever known, and the dispersion along the mean relation is 13% in dust temperature. This relation can be explained physically by a thin layer of heating sources embedded in a thicker, optically-thick dust screen. We also find that the number of galaxies sharply drops when galaxies become optically thin against dust-heating radiation, indicating that a feedback process to galaxy formation (e.g., by the photoelectric heating) is working when dust-heating radiation is not self-shielded on a galactic scale. We discuss implications from these findings for the MHI -size relation, the Kennicutt-Schmidt relation, and galaxy formation in the cosmological context.
        4,000원
        194.
        2012.09 KCI 등재 구독 인증기관·개인회원 무료
        We investigate the relation between star formation activity and PAH 3.3 μm emission. Our targets are mid-infrared-excess galaxies selected from the AKARI all-sky survey point source catalog. We performed AKARI near-infrared spectroscopy for them. As a result, we obtained 2.5 − 5 μm spectra of 79 galaxies, and selected 35 star-forming galaxies out of them. Comparing the PAH 3.3 μm luminosities with the infrared luminosities, we find a linear correlation between them. However, by adding the results from literatures for luminous infrared galaxies and ultra-luminous infrared galaxies that are more luminous than our sample, the ratio of the PAH to the infrared luminosity is found to decrease towards the luminous end.
        195.
        2012.09 KCI 등재 구독 인증기관·개인회원 무료
        Radio-loud active galaxies have been found to exhibit a close connection to galactic mergers and host galaxy star-formation quenching. We present preliminary results of an optical spectroscopic investigation of the AKARI NEP field. We focus on the population of radio-loud AGN and use photometric and spectroscopic information to study both their star-formation and nuclear activity components. Preliminary results show that radio-AGN are associated with early type, massive galaxies with relatively old stellar populations.
        196.
        2012.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We utilize AKARI's slitless spectroscopic capability to detect the 3.3 μm polycyclic aromatic hydrocarbons (PAHs) emission and measure star formation (SF) activity for various AKARI programs. First, we obtain 2∼5μm spectra of 20 flux-limited galaxies with mixed SED classes in order to calibrate the 3.3 μm PAH luminosity (LPAH 3.3) as a star formation rate (SFR) indicator. We find that LPAH3.3 correlates with LIR as well as with the 6.2 μm PAH luminosity ( LPAH 6.2). The correlations does not depend on SED classes. We find that ULIRGs deviate from the correlation between PAH luminosities and LIR, while they do not for the correlation between PAH luminosities. We suggest possible effects to cause this deviation. On the other hand, how AGN activity is linked to SB activity is one of the most intriguing questions. While it is suggested that AGN luminosity of quasars correlates with starburst (SB) luminosity, it is still unclear how AGN activity is connected to SF activity based on host galaxy properties. We are measuring SFRs for the LQSONG sample consisting of reverberation mapped AGNs and PG-QSOs. This is an extension of the ASCSG program by which we investigated the connection between SB and AGN activities for Seyferts type 1s at z ~ 0.36. While we found no strong correlation between LPAH3.3 and AGN luminosity for these Seyferts 1s, LPAH3.3 measured from the central part of galaxies correlates with AGN luminosity, implying that SB and AGN activities are directly connected in the nuclear region.
        3,000원
        197.
        2012.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The absorption features due to interstellar ices, especially H2O and CO2 ices, provide us with crucial information on present and past interstellar environments, and thus the evolutionary histories of galaxies. Before AKARI, however, few detections of ices were reported for nearby galaxies. The AKARI's unique capability of near-infrared spectroscopy with high sensitivity enables us to systematically study ices in nearby galaxies. Thus we have explored many near-infrared spectra ( 2.5−5μm ) of the 211 pointed observations, searching for the absorption features of ices. As a result, out of 122 nearby galaxies, we have significantly detected H2O ice from 36 galaxies and CO2 ice from 9 galaxies. It is notable that the ices are detected not only in late-type galaxies but also in early-type galaxies. We find that CO2 ice is more compactly distributed near the galactic center than H2O ice. Finally, we suggest that the gas density of a molecular cloud and UV radiation may be important factors to determine the abundance of ices.
        3,000원
        198.
        2012.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We present Spitzer IRS spectroscopy of CO2 ice toward 19 young stellar objects (YSOs) with luminosity lower than 1L⊙ . Pure CO2 ice forms only at elevated temperatures, T > 20 K, and thus at higher luminosities. Current internal luminosities of YSOs with L < 1L⊙ do not provide such conditions out to radii of typical envelopes. Significant amounts of pure CO2 ice would signify a higher past luminosity. We analyze 15.2 μm CO2 ice bending mode absorption lines in comparison to the laboratory data. We decompose pure CO2 ice from 12 out of 19 young low luminosity sources. The presence of the pure CO2 ice component indicates high dust temperature and hence high luminosity in the past. The sum of all the ice components (total CO2 ice amount) can be explained by a long period of low luminosity stage between episodic accretion bursts as predicted in an episodic accretion scenario. Chemical modeling shows that the episodic accretion scenario explains the observed total CO2 ice amount best.
        3,000원
        199.
        2012.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        An overview of the North Ecliptic Pole (NEP) deep multi-wavelength survey covering from X-ray to radio wavelengths is presented. The main science objective of this multi-wavelength project is to unveil the star-formation and AGN activities obscured by dust in the violent epoch of the Universe (z=0.5-2), when the star formation and black-hole evolution activities were much stronger than the present. The NEP deep survey with AKARI/IRC consists of two survey projects: shallow wide (8.2 sq. deg, NEP-Wide) and the deep one (0.6 sq. deg, NEP-Deep). The NEP-Deep provides us with a 15 μm or 18 μm selected sample of several thousands of galaxies, the largest sample ever made at these wavelengths. A continuous filter coverage at mid-IR wavelengths (7, 9, 11, 15, 18, and 24 μ m ) is unique and vital to diagnose the contribution from starbursts and AGNs in the galaxies at the violent epoch. The recent updates of the ancillary data are also provided: optical/near-IR magnitudes (Subaru, CFHT), X-ray (Chandra), FUV/NUV (GALEX), radio (WSRT, GMRT), optical spectra (Keck/DEIMOS etc.), Subaru/FMOS, Herschel/SPIRE, and JCMT/SCUBA-2.
        4,000원
        200.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to examine the effect of dietary n-3/n-6 fatty acid (FA) ratio on in vitro dry matter digestibility (IVDMD), fermentation indices and FA profile. Rice bran was mixed with oil sources (cotton seed oil and linseed oil) to make the diets at 0.02, 0.29 and 0.61 of dietary n-3/n-6 FA ratio. These diets (0.5g) were placed into the incubation bottles with 40 ml of anaerobic culture medium, which contained rumen fluid and Van Soest medium at 1:2 ratio. Five replicates of each diet and two blanks were incubated at 39℃ for 48 hours. After incubation, the incubated contents were centrifuged. The residues were freeze-dried for DMD and FA analyses. The supernatant was used for pH, NH3-N and volatile fatty acid analyses. The concentrations of lactate (p<0.001) and iso-valerate (p<0.001) decreased linearly with increasing dietary n-3/n-6 FA ratio, but acetate concentration (p=0.056) and the ratio of acetate to propionate (p=0.005) was increased linearly. The concentrations of n-3, n-6 FA and the ratio of n-3/n-6 FA in residues increased (p<0.001) linearly with increasing dietary n-3/n-6 FA ratio, but C18:1n-9 FA concentration was decreased (p<0.001) linearly. With these results, it could affect fermentation characteristics and FA profile of rumen content by dietary n-3/n-6 FA ratio.
        4,000원