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        검색결과 560

        241.
        2014.07 구독 인증기관·개인회원 무료
        The aim of the present research is to explore the neural features of intertemporal choice. Intertemporal choice concerns the phenomenon of temporal discounting which demonstrates consumers’ tendency to devalue a future reward as the receipt of money reward is delayed further distantly into the future. It is also called the ‘present bias,’ a special kind of attachment consumers place to immediate a cash reward which consumers are willing to take even at a discount, instead of saving it for the future. The urge to choose an immediate reward at some discounting rates, i.e., temporal impulsivity, is deeply embedded in our instinct. On the other hand, the choice for a delayed option is made as a result of effortful and deliberate cognitive control, by suppressing the urge for instant gratification and shifting focus to the long-term gain. Neuroscience researchers have found the prefrontal cortex as a key brain region behind deliberate and analytic decision-making such as reward delay. The experimental paradigm used in this study adopted from Kirby, Petry, & Bickel (1999). There were ten intertemporal investment choices representing six different levels of discounting rates. Participants (N=21) were given the two investment options, as “take it now” and a “save for later” options, and they were asked to indicate a preferred option. The brain waves were recorded using a 32 channel EEG system. We conducted noise control by using Independent Component Analysis (ICA) in EEGLAB and analyzed the Event-Related Potentials (ERP) particularly focusing on the phase when each participant was examining the future-oriented “save for later” option. The behavioral responses were divided into two groups, one in which the present option was selected and the other in which a future-oriented “save it for later” option was selected. Custom-written Matlab codes were used to compare the differences in ERPs between the two choice responses. A greater positive component of P3 after 300 milliseconds at the onset of the future option was observed in the fronto-parietal regions when the “save it for later” options were chosen compared to when the “take it now” choices were made. Hence, during intertemporal choice, the fronto-parietal regions are likely to play a key role in enabling the long-term perspective and consequently, precipitate the choice of a future-oriented deal. The P3 signal across the fronto-parietal regions may potentially be a proximal indicator of a future-oriented choice during intertemporal financial decision-making.
        242.
        2014.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper, the wakes behind a square cylinder were simulated using two kinds of different turbulence models for the eddy viscosity concept such as the zero- and the one-equation model in which the former is the mixing length model and the latter is the k-equation model. For comparison between numerical and analytical solutions, we employed three skill assessments: the correlation coefficient(r) for the similarity of the wake shape, the error of maximum velocity difference(EMVD) for the accuracy of wake velocity and the ratio of drag coefficient(RDC) for the pressure distribution around the structure. On the basis of the numerical results, the feasibility of each model for wake simulation was discussed and a suitable value for the empirical constant was suggested in these turbulence models. The zero-equation model, known as the simplest turbulence model, overestimated the EMVD and its absolute mean error(AME) for r, EMVD and RDC was ranging from 20.3 % to 56.3 % for all test. But the AME by the one-equation model was ranging from 3.4 % to 19.9 %. The predicted values of the one-equation model substantially agreed with the analytical solutions at the empirical mixing length scale L=0.6b1/2 with the AME of 3.4 %. Therefore it was concluded that the one-equation model was suitable for the wake simulation behind a square cylinder when the empirical constant for eddy viscosity would be properly chosen.
        4,200원
        243.
        2014.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study purposed to provide a scientific base for understanding the effect of therapeutic intervention using motivation on chronic stroke patients’balance and determining whether it is applicable as a new therapeutic intervention. For this study, we sampled 38 chronic stroke patients, and divided them randomly into a motivation training group(n=20) and a control group(n=18). To the control group was applied neurological physiotherapy 5 times a week, and 30 minutes each time, and to the motivation training group was applied neurological physiotherapy and then, additionally, a Nintendo Wii-Fit program 3 times a week, and 30 minutes each time. Before and after the experiment, the subjects’dynamic balance was measured with functional reach test(FRT), timed up & go test(TUG), and 10m gait test, and their static balance was measured with the Romberger Test. When dynamic balance ability was compared between before and after the experiment and between the motivation training group and the control group, significant difference was observed in the results of FRT, TUG, and 10m walking test between before and after the intervention(p<.05). As to static balance, in addition, body balance movement distance was not significantly different. Therapeutic intervention using dynamic motivation was found to be more effective than the control group in improving dynamic balance.
        4,000원
        244.
        2014.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to analysis of the effect of proprioceptor training and vestibular organ training for balance ability. The subjects was consist of two different subjects group, proprioceptor training group and vestibular organ training group. Proprioceptor training group consisted of 10 subjects and vestibular organ training group consisted of 10 subjects. Training was performed 3 times per week, 30 minutes per day, for 3 weeks. Balance ability analysis was performed using Romberg's one leg standing test and BT4 when opened eyes and closed eyes. The analysis results were as follows. There was no significant differences in balance after the training in both groups when they opened their eyes(p<.05). But there was significant differences in balance after the training in both groups when they closed their eyes(p<.05). And there was no significant difference in balance after the training between the proprioceptor training group and the vestibular organ training group when they closed their eyes(p<.05). Given the above results, proprioceptor training and vestibular organ training enhanced balance but there was no significant difference between the two methods.
        4,000원
        245.
        2014.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to observe how balance exercise on an unstable platform and on a stable platform affects balance ability. The subjects were 35 adults in their 20s and were randomly assigned to a stable platform group and an unstable platform group. They performed balance exercise three times per week for six weeks. Balance exercise introduced by previous research was modified and complemented for use in this study. Balance ability of the subjects was measured through center of pressure(COP) area, medial-lateral displacement, and anterior-posterior displacement using a portable balance platform BT4. There was significant difference in the COP area between the unstable platform exercise group and the stable platform exercise group. In comparison in differences between the unstable platform exercise group and the stable platform exercise group after the exercise, there was significant difference in anteriorposterior movement. Therefore, exercise on an unstable platform is more effective than exercise on a stable platform in strengthening balance ability.
        4,000원
        246.
        2013.12 구독 인증기관 무료, 개인회원 유료
        HyPer is the genetically encoded biosensor of intracellular hydrogen peroxide (H2O2), the most stable of the reactive oxygen species (ROS) generated by living cells. HyPer has a high sensitivity and specificity for detecting intracellular H2O2 by confocal laser microscopy. However, it was not known whether high speed ratiometric imaging of H2O2 by HyPer is possible. We thus investigated the sensitivity of HyPer in detecting changes to the intracellular H2O2 levels in HEK293 and PC12 cells using a microfluorometer imaging system. Increase in the HyPer ratio were clearly evident on stimulations of more than 100 μM H2O2 and fast changes in the HyPer ratio were observed on ratiometric fluorescent images after H2O2 treatment. These results suggest that HyPer is a potent biosensor of the fast temporal production of intracellular H2O2.
        4,000원
        247.
        2013.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 2010년부터 2011년까지 2년 동안 천수만 수질환경의 시공간적 특성을 조사하였다. 16개 정점에서 수층(표층과 저층)별 ․격월별로 년 6회 수온, 염분, 부유물질, 화학적산소요구량, 용존산소, 영양염류, 엽록소 a 에 대해 조사한 결과, 표층수와 저층수 간에는 아질산질소, 질산질소 및 용존무기질소을 제외한 모든 조사항목에서 표․저층 간의 차이가 컸었다. 공간적 분포특성은 전조사 항목에서 정점 간 차이가 적었으나, 주성분 분석결과 표층에서는 부남호 영향을 받는 정점 1 과 중간역인 정점 2∼11 및 입구쪽인 정점 12∼16로 구분되어지고, 저층에서는 표층과 마찬가지로 정점1과 죽도 북측연안의 정점 2∼7 및 정점 8∼16의 세 그룹으로 구분되었다. 격월별로는 저층의 부유물질을 제외한 전조사 항목에서 유의성이 입증되었으며, 정점별로 차이가 있어 내측은 격월별 변화가 큰 상태이었고 입구측으로 갈수록 변화폭이 줄어드는 경향이었다. 수질의 시간적 변동은 표층과 저층에서 세 그룹으로 구분되어지나 경향은 차이가 있었으며 대부분의 조사월에서 영양염류가 낮은 상태이었다. 생태기반 해수수질 기준은 Ⅱ등급(좋음) 수준이며, 격월별로는 6월과 8월은 Ⅲ등급(보통), 10월과 12월은 Ⅱ등급(좋음), 2월과 4월은 Ⅰ등급(매우좋음)으로 구분되어 경인연안, 아산연안, 목포연안 및 군산연안과 마찬가지로 육수 유입의 원인에 기인한 것으로 사료된다.
        5,500원
        248.
        2013.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The fact that flip-flops, one of many different types of unstable shoes, are light and relatively easy to put on, accounts for their popularity among people. But because flip-flops rely heavily on the support of a single thong between your first and second toes, they impose a huge amount of pressure onto lower leg. Thus in the following experiment we tried to examine the different effects of flip-flops and running shoes in terms of their effect on muscle activity and fatigue of tibialis anterior and gastrocnemius during walking. In order to measure an electromyogram we used Free EMG system. 10 men and 10 women in running shoes ran on treadmills for 15 minutes at 4.8km/h, 2 days later the same experiment was carried out, but this time, in flip-flops. p value turned out to be greater than .05 and thus there was no considerable difference between the effects of flip-flops and running shoes on muscle activity and fatigue during walking. Therefore we conclude that despite the fact that flip-flops are considered unstable, their effects on muscle activity and fatigue of tibialis anterior and gastrocnemius are negligible.
        3,000원
        249.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Near infrared reflectance spectroscopy (NIRS) has become increasingly used as a rapid and accurate method of evaluating some chemical compositions in forages and feedstuff. This study was carried out to explore the accuracy of near infrared spectroscopy (NIRS) for the prediction of chemical parameters of fresh whole crop barley silages. A representative population of 284 fresh whole crop barley silages was used as a database for studying the possibilities of NIRS to predict chemical composition. Samples of silage were scanned at 1 nm intervals over the wavelength range 680~2,500 nm and the optical data were recorded as log 1/Reflectance (log 1/R) and were scanned in fresh condition. NIRS calibrations were developed by means of partial least-squares (PLS) regression. NIRS analysis of fresh whole crop barley silages provided accurate predictions of moisture, acid detergent fiber (ADF), neutral detergent fiber (NDF), crude protein (CP) and pH, as well as lactic acid content with correlation coefficients of cross-validation (R2cv) of 0.96, 0.81, 0.79, 0.84, 0.72 and 0.78, respectively, and standard error of cross-validation (SECV) of 1.26, 2.83, 2.18, 1.19, 0.13 and 0.32% DM, respectively. Results of this experiment showed the possibility of the NIRS method to predict the chemical parameters of fresh whole crop barley silages as a routine analysis method in feeding value evaluation and for farmer advice.
        4,000원
        256.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The recent development in genetic assisted selection (combining traditional- and genome assisted selection method) and reproduction technologies will allow multiplying elite cow in Hanwoo small farm. This review describes the new context and corresponding needs for genome assisted selection schemes and how reproductive technologies can be incorporated to get more genetic gain for cow genetic improvement in Hanwoo. New improved massive phenotypes and pedigree information are being generated from commercial farm sector and these are allowing to do genetic evaluation using BLUP to get elite cows in Korea. Moreover cattle genome information can now be incorporated into breeding program. In this context, this review will discuss about combining the reproductive techniques (Multiple Ovulation Embryo Transfer; MOET) and genome assisted selection method to get more genetic gain in Hanwoo breeding program. Finally, how these technologies can be used for multiplication of elite cow in small farm was discussed.
        4,000원
        258.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        말똥성게 (Hemicentrotus pulcherrimus)의 생식세포 및 pluteus 유생을 이용하여 중금속인 Arsenic (As)와 Chromium (Cr)이 정상 수정률 및 배아 발생률에 미치는 독성 영향을 조사하였다. H. pulcherrimus의 수정률 및 배아 발생률에 미치는 As와 Cr의 독성은 6.25, 12.5, 25, 50, 100 ppb의 농도에서 조사하였다. 0.5 M KCl 용액을 이용하여 방란 및 방정을 유도하였고, 정상 수정률 및 배아발생률은 수정 후 각각 10분 및 64시간째 관찰하였다. As와 Cr을 첨가하지 않은 대조구에서 정상 수정률과 배아 발생률은 각각 94%와 93% 이상을 나타냈다. 이들 중금속 첨가에 의해 수정률은 아무런 변화가 나타나지 않았지만 배아 발생률은 농도 의존적 감소하는 것으로 나타났으며, As의 첨가에 의해 배아 발생률은 6.25 ppb에서 유의적으로 감소하였으며 (P⁄0.01), Cr의 경우는 25 ppb에서 유의적인 감소를 나타냈다 (P⁄0.05). H. pulcherrimus의 정상 배아 발생률에 대한 LOEC는 As의 경우는 6.25 ppb를 Cr은 25 ppb를 나타냈다. 이들 연구결과로 해양생태계 내에서 As가 6.25 ppb, Cr이 25 ppb를 초과하는 농도일 때는 H. pulcherrimus와 같은 무척추동물의 정상부화율은 급격히 감소할 것으로 판단된다. 본 연구결과를 바탕으로, H. pulcherrimus의 정상 배아 발생률을 이용한 생물학적 평가방법은 중금속과 같은 유해물질에 대한 해양생태계의 영향을 판단하기 위한 시험방법으로 유용하게 이용될 수 있을 것으로 판단된다.
        4,000원
        259.
        2013.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aims to address the effect of interferential current therapy and thereby to provide basic resources to physical therapies for internal medicine by identifying symptoms for functional dyspepsia and serum gastrin level that shows gastric motility. Following results were obtained by performing interferential current therapy to 16 subjects composed of 8 for functional dyspepsia group and 8 for control group for 20 minutes a day, 3 days a week, for 6 weeks. In control group, serum gastrin level was significantly( p<.01), lowered after the therapy whereas there was no significant difference observed in all questions from questionnaire for symptoms of functional dyspepsia between before and after the therapy. In functional dyspepsia group, serum gastrin level was significantly(p<.01), lowered after the therapy and there was also significant(p<.01) reduction in every question from questionnaire for symptoms of functional dyspepsia between before and after the therapy. There was more significant decrease in serum gastrin level and reduction in questionnaire for symptoms of functional dyspepsia in the functional dyspepsia group compared to the control group(p<.01). This study confirms the interferential current therapy as an effective therapeutic method for internal diseases including functional dyspepsia since it not only improves the symptoms of functional dyspepsia but also allows the gastric motility close to normal.
        4,000원
        260.
        2013.04 구독 인증기관·개인회원 무료
        The oriental tobacco budworm, Helicoverpa assulta, is an oligophagous insect feeding on a few species of Solanaceae plants, including Nicotina tabacum. This study investigated the relationship between H. assulta and plants, focusing on oviposition preference and larval performance of the specialist in host and non-host plants. (1) In choice experiments, N. tabacum and Phaseolus vulgaris were put in a cage with 5 females and 10 males. Most of eggs (ca. 98%) were layed in N. tabacum, whereas few eggs in P. vulgaris. (2) In non-choice experiments, N. tabacum, Datura stramonium, or P. vulgaris was individually put in a cage with 3 females and 6 males, resulting that N. tabacum was the most preferred host, followed by D. stramonium and P. vulgaris. Oviposition was delayed about 2 days in P. vulgaris (a non-host plant) compared to the two host plants. (3) Larval performances were also compared with the three plants. Larval growth was better in N. tabacum followed by D. stramonium and P. vulgaris, High mortality (ca. 100%) of larvae was observed in P. vulgaris, suggesting toxic component(s) derived from the non-host plant might cause the death. The ovipositional avoidance in P. vulgaris is current being investigated to search for the oviposition deterrent, which could be useful for the environment-friendly pest management of H. assulta.