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        검색결과 9

        1.
        2024.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We aimed to evaluate the effectiveness of ensemble optimal interpolation (EnOI) in improving the analysis of significant wave height (SWH) within wave models using satellite-derived SWH data. Satellite observations revealed higher SWH in mid-latitude regions (30o to 60o in both hemispheres) due to stronger winds, whereas equatorial and coastal areas exhibited lower wave heights, attributed to calmer winds and land interactions. Root mean square error (RMSE) analysis of the control experiment without data assimilation revealed significant discrepancies in high-latitude areas, underscoring the need for enhanced analysis techniques. Data assimilation experiments demonstrated substantial RMSE reductions, particularly in high-latitude regions, underscoring the effectiveness of the technique in enhancing the quality of analysis fields. Sensitivity experiments with varying ensemble sizes showed modest global improvements in analysis fields with larger ensembles. Sensitivity experiments based on different decorrelation length scales demonstrated significant RMSE improvements at larger scales, particularly in the Southern Ocean and Northwest Pacific. However, some areas exhibited slight RMSE increases, suggesting the need for region-specific tuning of assimilation parameters. Reducing the observation error covariance improved analysis quality in certain regions, including the equator, but generally degraded it in others. Rescaling background error covariance (BEC) resulted in overall improvements in analysis fields, though sensitivity to regional variability persisted. These findings underscore the importance of data assimilation, parameter tuning, and BEC rescaling in enhancing the quality and reliability of wave analysis fields, emphasizing the necessity of region-specific adjustments to optimize assimilation performance. These insights are valuable for understanding ocean dynamics, improving navigation, and supporting coastal management practices.
        4,600원
        2.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ischemic stroke is a high mortality disease that causes irreversible damage. Chlorogenic acid is a polyphenolic substance with neuroprotective properties. Bcl-2 family proteins perform a critical role in apoptosis process. Bcl-2 and Bcl-xL are anti-apoptotic proteins that prevent cell death, and Bax and Bad are pro-apoptotic proteins that promote apoptosis. We investigated whether chlorogenic acid modulates Bcl-2 family proteins during focal cerebral ischemia. We made a rat model of ischemic stroke by performing middle cerebral artery occlusion (MCAO). Chlorogenic acid (30 mg/kg) or phosphate-buffered saline was treated via intraperitoneal injection 2 hr before MCAO. Neurological behavioral tests were performed 24 hr after MCAO damage and cortical tissues were collected. Reverse transcription-PCR, Western blot, and immunofluorescence staining were performed to observe changes in Bcl-2 family proteins expression. MCAO-damage induced neurobehavioral disorders and chlorogenic acid alleviate these deficits. Bcl-2 and Bcl-xL expressions were decreased and Bax and Bad expressions were increased in MCAO animals. However, chlorogenic acid treatment attenuated the decrease of Bcl-2 and Bcl-xL and the increase of Bad and Bax due to MCAO surgery. Moreover, chlorogenic acid treatment attenuated MCAO-induced upregulation of caspase-3. These findings suggest that chlorogenic acid exerts neuroprotective effects against MCAO damage by regulating Bcl-2 family proteins including Bcl-2, Bcl-xL, Bax, and Bad.
        4,200원
        3.
        2018.10 구독 인증기관·개인회원 무료
        최근 해충방제를 위해 유인헬기와 무인헬기를 이용한 수도작, 과수, 산림 등에서 대면적으로 약제살포가 이루어지고 있는 실정이다. 헬기는 비교적 높은 고도에서 비행하면서 약제를 살포하여 살포여건에 따라 약제가 목적이외의 지역으로 표류하여 부작용을 초래할 수도 있다. 따라서 본 연구는 소나무림의 소나무재선충 매개충과 밤나무림의 종실해충 방제지를 대상으로 유인헬기(소형, 대형)와 무인헬기(드론)의 약제살포 입자의 비산양상을 조사하고 다른 한편으로는 유·무인 헬기를 이용한 약제살포 실연을 통해 입자의 비산 양상을 조사하였다. 방제 실행지 조사에서 유인헬기(대형)의 경우 약제 입자의 최대 비산거리는 100 m였으며, 무인헬기(드론)의 경우 비산거리 30 m인 것으로 나타났다. 유무인 헬기를 이용한 실연 조사에 있어서도 약제입자의 최대 비산거리는 소형헬기의 경우 30 m, 대형헬기의 경우에는 100 m였으며, 드론의 경우에는 30 m로 나타났다. 동일한 조건에서 약제입자는 특정방향으로 비산되는 경향을 보여 풍향의 영향이 크게 미치는 것으로 판단되며 동일한 살포기종에 있어서 조사 시기에 따라 비산거리에 차이를 보이는 것은 약제살포 시간대의 풍속이 크게 영향을 미치는 것으로 판단된다.
        5.
        2017.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Magnetic flux ropes, often observed during intervals of interplanetary coronal mass ejections, have long been recognized to be critical in space weather. In this work, we focus on magnetic flux rope structure but on a much smaller scale, and not necessarily related to interplanetary coronal mass ejections. Using near-Earth solar wind advanced composition explorer (ACE) observations from 1998 to 2016, we identified a total of 309 small-scale magnetic flux ropes (SMFRs). We compared the characteristics of identified SMFR events with those of normal magnetic cloud (MC) events available from the existing literature. First, most of the MCs and SMFRs have similar values of accompanying solar wind speed and proton densities. However, the average magnetic field intensity of SMFRs is weaker (~7.4 nT) than that of MCs (~10.6 nT). Also, the average duration time and expansion speed of SMFRs are ~2.5 hr and 2.6 km/s, respectively, both of which are smaller by a factor of ~10 than those of MCs. In addition, we examined the geoeffectiveness of SMFR events by checking their correlation with magnetic storms and substorms. Based on the criteria Sym-H < -50 nT (for identification of storm occurrence) and AL < -200 nT (for identification of substorm occurrence), we found that for 88 SMFR events (corresponding to 28.5 % of the total SMFR events), substorms occurred after the impact of SMFRs, implying a possible triggering of substorms by SMFRs. In contrast, we found only two SMFRs that triggered storms. We emphasize that, based on a much larger database than used in previous studies, all these previously known features are now firmly confirmed by the current work. Accordingly, the results emphasize the significance of SMFRs from the viewpoint of possible triggering of substorms.
        6.
        2017.05 서비스 종료(열람 제한)
        Background : The purpose of this study was to evaluate methods to high quality food ramie rice cake, thereby increasing farm income. This study investigated the effects of different Split Application and Adapted Fertilizer Culture for Stable Production with Edible Leaf in Ramie (Boehmeria nivea L.). Methods and Results : Method of fertilizer application were conducted under three condition compose to standard application (N-P-K-Compost applied at 27-9-27-1,500 ㎏․ 10 a−1), 25% increased application (N-P-K-Compost applied at 34-11-34-1,500 ㎏․10 a−1), 50% increased application (N-P-K-Compost applied at 41-14-41-1,500 ㎏․ 10 a−1) cultivation. Compost and fused phosphate applied at 100% of basal fertilizer in March 25. The split application level of standard application (N-K) applied at 50% of basal fertilizer in March 25, 50% of top dressing were five times application (N-K) in May 4, July 5, September 5, October 5, 20% respectively. Transplanting with Yeongkwang varieties in April 12 by growing pot seedling for 35 days in 2011. Planting density were spaced 60 ㎝ apart in rows 25 ㎝ apart with rice straw cutting covered open cultivation. Plot design randomized block 3 repetition. Conclusion : Organic matter, available phosphate, K2O, CaO, and MgO of soil increased in all plots with the addition of fertilizers culture, specifically in 25% and 50% increased application. Growth characteristics by 50% of top dressing were five times application (N-K) in May 4, July 5, September 5, October 5, compared to standard application (N-K) applied at 100% basal fertilizer, aerial part as a result were so many such amount of growth as number of branch and leaf per plant, etc., Length, width of leaf and leaf colorimetry of aboveground part growth increment rising highest. Green leaf yields compared to standard fertilizer 100% application (1,344 kg․ 10 a−1). 25% and 50% increased application (N-K) applied at 50% basal fertilizer, 50% of top dressing were five times application increased by 9%, 17%. respectively.
        7.
        2012.12 KCI 등재 서비스 종료(열람 제한)
        Manganese () is a trace element that is essential for normal physiology, and is predominantly obtained from food. Several lines of evidence, however, demonstrated that overexposure to exerts serious neurotoxicity, immunotoxicity and developmental toxicity, particularly in male. The present study aimed to evaluate the effect of 0, 1.0, 3.3, and 10 mg/kg/day doses of on the reproductive organs in the immature female rats. Rats (PND 22; S.D. strain) were exposed to () dissolved in drinking water for 2 weeks. The animals were sacrificed on PND 35, then the tissues were immediately removed and weighed. Histological studies were performed using the uteri tissue samples. Serum LH and FSH levels were measured with the specific ELISA kits. Body weights of the experimental group animals were not significantly different from those of control group animals. However, ovarian tissue weights in 1 mg and 3.3 mg dose groups were significantly lower than those of control animals (p<0.05 and p<0.01, respectively). Uterine tissue weights of 3.3 mg dose groups were significantly lower than those of control animals (p<0.01), while the 1 mg dose and 10 mg dose failed to induce any change in uterine weight. Similarly, only 3.3 mg dose could induce the significant decrease in the oviduct weight compared to the control group (p<0.05). Non-reproductive tissues such as adrenal and kidney failed to respond to all doses of exposure. The uterine histology revealed that the exposure could affect the myometrial cell proliferation particularly in 3.3 mg dose and 10mg dose group. Serum FSH levels were significantly decreased in 1mg dose and 10 mg groups (p<0.05 and p<0.01, respectively). In contrast, treatment with 1 mg dose induced a significant increment of serum LH level (p<0.05). The present study demonstrated that exposure is capable of inducing abnormal development of reproductive tissues, at least to some extent, and altered gonadotropin secretions in immature female rats. Combined with the well-defined actions of this metal on GnRH and prolactin secretion, one can suggest the might be a potential environmental mediator which is involved in the female pubertal process.