We examined a total of 166 images of 3.5 μm H3+ emission in the auroral regions of Jupiter observed with the Protocam on IRTF in 1991 and 1992, and found that 30 images contain a clearly isolated small emission patch in the vicinity of the northern auroral regions. Two different time sequences of the images show the small patches at the dusk limb in the range of System III longitudes from 270° through 0° to 90°. The small patches in one sequence of the images, which were taken at 10 phase between 240° and 260°, may be related to the 10 flux tube, similarly suggested by Connerney et al. (1993). However, the small patches in the other sequence are separated from Io as much as 80° in longitude. The positions of the small patches in both sequences are deviated equatorward from the 10 footprint oval by 5° - 8° latitude in the longitudinal range of 270° - 360°. A significant modification is required in current Jovian magnetic field models near the Jupiter's surface if the small patches are produced at the foot of the 10 flux tube.

방사선 피폭감소를 위해 사용하는 비스무스 차폐체를 적용하여 CT스캔 시 차폐체에 의한 선속경화현상으로 화질이 감소되는 경우가 있다. 이에 G사의 듀얼 에너지 CT의 GSI모드 적용을 통해 화질저하 현상을 줄일 수 있는 에너지 영역대를 찾아보고, 가능성을 실험을 통해 알아보고자 하였다. 그 결과 비스무스 차폐 후 듀얼 에너지 CT 스캔 시 50 keV에서 118±10.6 HU, 50.1±14.6 HU로 화질저하 전 CT value와 가장 유사 하였고(p>0.05), Image J의 Multi-point기능을 적용한 Pixel value에서도 50 keV에서 176.6±7.1, 138.3±1.1로 측정 되었다(p>0.05). CT검사 시 차폐체의 사용은 불가항력적으로 화질저하를 유발하지만 듀얼 에너지 CT 의 GSI기능 적용으로 차폐체를 사용하고도 화질을 유지할 수 있다는 것을 실험을 통해 알 수 있었다. 향후 다양한 차폐체를 듀얼 에너지 CT를 이용, 평가 후 보안 한다면 CT검사의 최대 단점인 피폭 감소를 위한 방사선 차폐체 사용으로 발생한 화질저하라 단점을 극복할 수 있을 것으로 기대된다.

본 연구에서는 비슬산 이중편파 Radar 자료와, GPM 위성자료 및 21개 (Korea Meteorological Administration, KMA) 지상강우자료를 활용하여 분포형 강우-유출 모형(KIneMatic wave STOrm Runoff Model2, KIMSTORM2)을 이용해 남강댐 유역(2,293 km2)을 대상으로 유출해석을 수행 하였다. 모형의 유출 해석은 2016년 10월 5일 02:00∼09:00 총 8시간 동안 최대강우강도 33 mm/hr, 유역평균 총 강우량 82 mm이 발생한 태풍 차 바(CHABA)를 대상으로 하였으며, Radar 및 GPM 자료와 조건부합성(Conditional Merging, CM) 기법을 적용한 Radar (CM-corrected Radar) 및 GPM (CM-corrected GPM) 자료를 각각 활용하여 결과를 비교하였다. 이 때, 공간 강우자료에 유출 검보정은 남강댐 유역 내 3개의 수위관측 지점(산청, 창촌, 남강댐)을 대상으로 실시하였으며, 모형의 매개변수 초기토양수분함량, 지표와 하천의 Manning 조도계수를 이용하여 검보정하였다. 유출 결과는 결정계수(Determination coefficient, R2), Nash-Sutcliffe의 모형효율계수(NSE) 및 유출용적지수(Volume Conservation Index, VCI)를 산정하였다. 그 결과 CM-corrected Radar, GPM 자료가 평균 R2는 0.96, NSE의 경우 0.96, 유출용적지수(VCI)는 1.03으로 가장 우수한 결과를 나타내었다. 최종적으로 CM 기법을 이용한 보정된 공간분포자료는 기존의 자료에 비해 시공간적으로 정확한 홍수 예측에 사용 될 것으로 판단된다.

본 연구에서는 보령댐 유역(163.6 km2)을 대상으로 SWAT (Soil and Water Assessment Tool) 모델, GCM (General Circulation Model) 기 후변화 시나리오와 다중회귀분석으로 산정한 미래 방류량을 활용하여 극한 기후변화 사상이 반영된 보령댐의 물부족을 평가하였다. 유역의 물수지 분석을 위해 보령댐 유역을 대상으로 기상자료, 보령댐 운영자료를 수집하였으며, SWAT 모형의 신뢰성 있는 유출량 보정을 위해 보령댐의 실 측 방류량을 이용하여 댐 운영모의를 고려하였고 유입량 및 방류량 자료를 활용하여 모형의 보정(2007~2010)과 검증(2010~2016)을 실시하였다. 기후변화를 반영하기 위해 APCC의 26개 CMIP5 GCM 자료 중 RCP (Representative Concentration Pathway)4.5와 RCP 8.5 시나리오를 SPI와 극한 가뭄지수로 분석하여 RCP 8.5 BCC-CSM1-1-M을 극한 가뭄 시나리오로 선정하였다. 2005년부터 2016년까지의 일별 관측자료로 다중회귀분석하여 월별 방류량 추정식을 만들었고, 1월부터 12월까지 각 식들의 결정계수 R2는 0.57 이상으로 나타났다. 선정된 극한 가뭄 시나리오 기상자료를 방류량 추정식에 대입하여 미래기간 일별 방류량을 구축하였다. SWAT 수문평가 결과, S3 (2037~2046) 기간 봄철 저수량이 34.0% 감소하는 것으로 분석되었다. Runs 이론을 바탕으로 물부족의 심도를 구한 다음 재현기간에 따른 빈도해석을 하였다. 5~10년 빈도의 심 도로 발생하는 물부족이 미래기간에 발생하는 빈도로 보령댐의 물부족을 평가하였다. 물부족 평가 결과, S3 (2037~2046) 기간에서 5~10년 빈도의 심도를 가지는 물부족이 기준기간(2007~2016) 보다 2회 더 발생하였으며 S3 (2037~2046)에 물부족 계획 수립이 필요하다고 판단하였다.

본 연구는 경기도 소재 대학병원에 2018년 1월1일부터 2018년 6월30일까지 복부 CT검사를 위해 내원한 모든 환자의 영상 중 무작위로 선정하여 복부 면적의 크기 별로 20명 씩 60명을 총 3군으로 분류하여 복부 CT영상의 면적에 따른 유효선량과 화질의 변화정도를 알아보았다. 그 결과 평균면적 군 에서 유효선량이 7.34 mSv로, 평균면적이상 군은 8.39 mSv, 평균면적이하 군은 5.89 mSv로 측정 되었다. 화질분석을 위해 복부면적에 따라 동일한 3영역에 ROI를 그려 비교해본 결과 3군으로 분류한 복부면적에서 모두 CT value가 유의한 차이가 있는 것으로 분석되었다(p<0.05). 향후 실제 임상에서 적용할 수 있는 프로토콜을 개발 시 본 연구결과를 기초자료로 활용할 수 있을 것으로 사료되며 현재 임상에서 CT검사 시 적용하고 있는 다양한 선량감소 프로그램을 적용 및 복부 면적 외 다양한 환자의 변환 조건 등을 고려하여 연구와 고찰을 도출한다면 화질과 피폭선량 감소에 도움을 줄 수 있을 것으로 사료된다.

본 연구의 목적은 금강유역(9,645.5 km2)을 대상으로 극한 기후변화 사상에 따른 수문 및 유황의 변동을 평가하는 것이다. 본 연구에서는 객관적인 극한 기후변화 사상을 평가하기 위해 강우관련 극한지수(STARDEX)를 적용하고, GCM 10개의 RCP 8.5 기후변화 시나리오에 대해 4개의 평 가기간별(Historical: 1975~2005, 2020s: 2011~2040, 2050s: 2041~2070, 2080s: 2071~2100)로 분석하였다. 분석 결과 5개의 습윤 (CESM1-BGC, HadGEM2-ES), 중간(MPI-ESM-MR) 건조(INM-CM4, FGOALS-s2) 극한 기후변화 사상 시나리오를 선정하여 SWAT 모형에 적용하였다. 2080s 기간에서 중간시나리오 대비 2080s의 증발산은 -3.2~+3.1 mm로 변화하였고, 2080s의 총 유출량은 +5.5~+128.4 m3/s 변화하였다. 건조한 시나리오의 경우 2020s 중간시나리오대비 큰 변화를 보였다. 건조한 시나리오에서의 2020s의 증발산량은 -16.8~-13.3 mm 의 변화를 보였고, 총 유출량은 -264.0~132.3 m3/s의 변화를 보였다. 유황 변동의 경우, 2080s 기간의 습윤한 시나리오에서 CFR은 +4.2~+10.5, 2020s 기간의 건조한 시나리오에서는 +1.7~2.6으로 변화 하였다. 극한 기후변화 시나리오를 적용한 금강유역의 수문인자의 변화에 따라 유황분 석을 실시한 결과, INM-CM4는 극한 건조상태를 나타내기에 적절한 시나리오로 나타났고 FGOALS-s2는 유황변동이 큰 가뭄 상태 분석에 적절한 시나리오로 나타났다. HadGEM2-ES는 유황변동이 작게 나타났기 때문에 최대유량 분석 시 활용 가능한 시나리오로 평가되었고, CESM1-BGC 의 경우 유황변동이 큰 것으로 나타나 극한 홍수 분석 시 적용할 수 있는 시나리오로 평가되었다.

본 연구의 목적은 기상자료(강수량, 최고기온, 최저기온, 평균기온, 평균풍속) 기반의 다중선형 회귀모형을 개발하여 농업용저수지 저수율을 예측 하는 것이다. 나이브 베이즈 분류를 활용하여 전국 1,559개의 저수지를 지리형태학적 제원(유효저수량, 수혜면적, 유역면적, 위도, 경도 및 한발빈도)을 기준으로 30개 군집으로 분류하였다. 각 군집별로, 기상청 기상자료와 한국농어촌공사 저수지 저수율의 13년(2002~2014) 자료를 활용하여 월별 회귀모형을 유도하였다. 저수율의 회귀모형은 결정계수(R2)가 0.76, Nash-Sutcliffe efficiency (NSE)가 0.73, 평균제곱근오차가 8.33%로 나타났다. 회귀모형은 2년(2015~2016) 기간의 기상청 3개월 기상전망자료인 GloSea5 (GS5)를 사용하여 평가되었다. 현재저수율과 평년저수율에 의해 산정되는 저수지 가뭄지수(Reservoir Drought Index, RDI)에 의한 ROC (Receiver Operating Characteristics) 분석의 적중률은 관측값을 이용한 회귀식에서 0.80과 GS5를 이용한 회귀식에서 0.73으로 나타났다. 본 연구의 결과를 이용해 미래 저수율을 전망하여 안정적인 미래 농업용수 공급에 대한 의사결정 자료로 사용할 수 있을 것이다.

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.

Background : Plants of Taraxacum spp. are widely used in medicine, but some of them have some problems related to propagation, such as strong dormancy and inactive germination. This study investigated the effects of temperature, gibberellic acid (GA3), and potassium nitrate (KNO3) on seed germination in Taraxacum ohwianum. Methods and Results : The seeds (NIBRGR0000135524) were exalbuminous, and their length and width were 4.25 ± 0.118 mm and 0.89 ± 0.062 mm, respectively. Among various temperatures (15, 20, 25, and 30℃), the optimum temperature for germination was found to be 20℃ (31.3%). High temperature (30℃) induced off-type in seedlings (thickened and crumpled cotyledons, and restricted root system). GA3 treatments increased germination percentage and speed, but germination percentage was higher with KNO3 treatment. Under KNO3 treatments (50 to 200 mg·L-1), germination percentage exceeded 80% after 12 days, with 50 mg·L-1 KNO3 being notably effective (91.2%, after 15 days). Conclusion : Seeds of T. ohwianum showed germination ability at low temperature. The best method for germination was pre-soaking in 50 mg·L-1 KNO3 (4℃, dark, 24 h) and incubating at 20℃ for 15 days.

Background : This study was conducted to determine the optimal conditions of growth medium, temperature, and light quality for efficient propagation of Pyrrosia petiolosa spores. Methods and Results : P. petiolosa spores were collected from Andong-si area in February 2015, and the spores were subjected to a careful selection process. The selected spores were stored at the Korea National Wild Plant Seed Bank (4℃, RH 40%) and used as our experimental materials (GR0000182302). The spore germination rate and prothalium development were high in Knop media (24.5%), which had low mineral content. The germination rate increased with the increase in temperature and reached its maximum, 24.5%, at 25°C. The germination rate was also measured under different light conditions, and the highest rate of 28.7% was observed under LED blue light compared to fluorescent lights (24.5%). The germinated spores developed into heart-shaped prothallia under LED blue light; however, 3 weeks after sowing, prothallium development decreased compared to fluorescent lights. Conclusion : In conclusion, the optimal P. petiolosa In vitro propagation method include spore germination on Knop medium at 25°C under LED blue light, and the change in light source to fluorescent light 3 weeks after sowing for prothallium formation and proliferation.

Citrus canker caused by Xanthomonas citri is a notorious disease affecting a decrease in fruit productivity and quality. Citrus export to USA is also prohibited by the disease. Therefore, development of citrus canker resistant variety is essential and exploitation of markers for molecular breeding is urgent. To develop DNA molecular markers, we performed whole genome resequencing for 8 varieties: 4 citrus canker resistant varieties including C. hybrid ‘Kioymi’ and 4 citrus canker susceptible varieties including C. iyo ‘Miyauchiiyokan’. In total, 642 polymorphic SNPs were detected between resistant and susceptible varieties. Of the 642 SNPs, 50 SNPs were preferably selected based on integrative genomics viewer. To apply the markers in a broad range of citrus variety, we performed genotyping with 6 other varieties very well known as citrus canker resistant and susceptible varieties in addition to previous mentioned 8 varieties. Three of the 50 SNPs were identified as a marker to distinguish citrus canker resistant varieties from susceptible varieties. Secondly, we developed molecular markers to apply for F1 lines crossed by ‘Kiyomi’ and ‘Miyauchiiyokan’. Of the 50 SNPs, we identified 2 SNP markers to distinguish between F1 resistant and susceptible lines. One of them is a resistance gene that plays a role in plant defense mechanism. In this study, we developed 5 molecular marker candidates possible to apply for molecular breeding to develop citrus canker resistant variety. We are working on development of candidate markers related to citrus canker.

Treatment of spontaneous retroperitoneal hemorrhage (SRH) is mainly conservative. However, if intra-abdominal hypertension (IAH) or abdominal compartment syndrome (ACS) develops, the treatment strategy should be more aggressive. Surgical decompression has been the gold standard; however, it is very invasive and highly morbid. Thus, percutaneous catheter drainage (PCD) has been introduced as an alternative therapeutic option. We report on a case of successful PCD for prevention of progression of IAH to ACS in a patient with SRH after coronary stent implantation. This case showed that PCD can be an efficacious and safe method for treatment of IAH with impending ACS.

Citrus canker caused by Xanthomonas citri pv. citri is one of economically important diseases in the citrus industry. The devastating bacterial disease results in unattractive quality and a significant reduction in fruit production. Citrus growers and industry in Korea has been struggling with the serious disease causing the prohibition of export market. Korea also became the top import market for oranges. The development of markers linked to citrus canker resistance is strongly needed. In this study, we investigated molecular markers between ‘Kiyomi’ (Citrus unshiu ｘ C. sinensis), a resistant cultivar, and Natsudaidai (C. natsudaidai), a susceptible cultivar. To develop markers, we focused on structural variation (copy number variation, CNV, and presence/absence variation, PAV). It has been well documented that CNV and PAV of defense-related genes are associated with resistant cultivars. Using a read depth approach following next-generation sequencing, we performed genome-wide analysis of CNV and PAV in two varieties. As a result, 633 genes showing at least two times difference between the mapping reads from two varieties and 61 genes showing presence of the mapping reads in only either one of them were screened. Visual inspection using the Integrative Genomics Viewer (IGV) was performed and experimental validation is being investigated. Interestingly, one of PAV candidates showed polymorphism in ‘Kiyomi’ and ‘Natsudaidai’ as well as other resistant and susceptible cultivars. Our results suggest a necessity for the detection of structural variation and indicate that the candidates may be useful for molecular breeding for citrus canker resistance and understanding disease resistance mechanism.

Ramie (Boehmeria nivea L. Gaudich.) is a hardy perennial herbaceous plant of the Urticaceae family and has been grown as a fiber crop in several countries including Korea for many centuries. Ramie leaves also have been traditionally used as a major ingredient of a type of rice cake called ‘Song-pyun’ in the Southwest area of Korea, especially Yeong-Gwang province. Despite its economic importance, the molecular genetics of ramie have not been studied in detail yet. Genetic resources of ramie were widely collected from domestic local sites by Bioenergy Crop Research Center (RDA) and Yeong-Gwang Agricultural Technology Center. For the systematic and efficient management of the genetic resources, we developed microsatellite molecular markers of ramie. To do this, we generated microsatellite-enriched genomic DNA libraries using magnetic bead hybridization selection method. 216 contigs containing microsatellite repeat motif were generated using nucleotide sequences of 376 clones from the libraries. Primer sets were designed from the flanking sequences of the repeat motif. Finally, we selected 26 microsatellite markers, possibly showing polymorphism among the genetic resources. Results on the genotype analysis of the ramie genetic resources using the microsatellite markers will be presented.

TCR subunits are members of membrane-bound receptors which allow the fast and efficient elimination of the specific fish pathogens have regulated function in adaptive immunity. Sequence structure of TCR subunits have been reported for various teleosts, but the information of each TCR subunit functional characterization through expression analysis in fish was unknown. In this study, we examined the gene expression of TCR subunits in the early developmental stages and observed transcript levels in various tissues from healthy adult olive flounder by RT-PCR. The mRNA expression of alpha subunit was already detected in the previous hatching step. But the transcripts of another TCR subunit were not observed during embryo development and increased after hatching and maintained until metamorphosis at the same level. It was found that all TCR subunits mRNAs are commonly expressed in the immune-related organ such as spleen, kidney and gill, also weak expressed in fin and eye. TCR alpha and beta subunit were expressed in brain, whereas gamma and delta were not expressed same tissue. The sequence alignment analysis shows that there are more than 80% sequence homology between TCR subunits. Because it has a high similarity of amino acid sequence to expect similar in function, but expression analysis show that will have may functional diversity due to different time and place of expression.

The innate immune system is the only defense weapon that invertebrates have, and it is the fundamental defense mechanism for fish. The innate immune response is important in newly hatched flounders because it is closely involved in the initial feeding phase, which is why it is essential for survival during the juvenile period. The expression analysis of genes involved in the innate immune response in the olive flounder (Paralichthys olivaceus) in the days after hatching is incomplete. Therefore, we have begun to examine the expression patterns of genes specifically induced during the development of the innate immune system in newly hatched flounders. Microscopic observation showed that pronephron formation corresponded with the expression of perforin-encoding gene. These results suggest that perforin plays a vital role in the innate immunity of the kidney during developmental stages. Perforin expression was strong at the start of the development of the innate immune response, and continued throughout all the development stages. Our findings have important implications with respect to perforin’s biological role and the evolution of the first defense mechanisms in olive flounder. Further studies are required to elucidate the perforin-mediated innate immunity response and to decipher the functional role of perforin in developmental stages.

Fish larvae are immediately exposed to microbes from hatching to maturation of their lymphoid organs, therefore effective innate mechanisms is very important for survival in such an environment. The key component of innate immune system, C3 is central protein of all activation pathways of the complement system, leading to inflammatory reactions, such as opsonisation, chemotaxis, and cell lysis of pathogens. Although, innate mechanisms is essential for survival in the early stage of development, little is known about defence mechanisms. In this study, the alignment analysis showed that amino acid sequence of C3 from olive flounder liver EST homologous to other known C3 sequences with 73-99% identity. Also, we examined the tissue distribution of olive flounder C3 and analyzed expression pattern from the fertilized egg until 28 days post hatching. As a result, olive flounder C3 mRNA was expressed only in the liver and the mRNA level more increased as developmental proceed during the early stage. These results may suggest that olive flounder C3 plays an important function in the early immune response of olive flounder larvae.

Development of transgenic plant with desirable traits to cultivated plant is one of the important procedures in plant molecular breeding. However, applicable assessment of transgenic plant in laboratorial scale is not much except cultivating transgenic plant for a whole life in field condition. Here, we analyzed chlorophyll fluorescence in three transgenic soybean lines with AtMYB44 transcription factor for assessment of photosynthetic activity under abiotic stresses such as drought. Soybean varieties used in this study were ‘Bert’ and ‘Bert’ derived three transgenic soybeans, ‘AtMYB44 CM35101’, ‘AtMYB44 CM2471’, and ‘AtMYB44 CM4481’. Analyzed five different chlorophyll fluorescence variables are maximum PSII quantum yield (QY_max), steady state PSII quantum yield (QY_Lss), steady state non-photochemical quenching (NPQ_Lss), coefficient of photochemical quenching in steady-state (Qp_Lss), and fluorescence declineratio in steady-state (Rfd_Lss). To determine main chlorophyll fluorescence variable affected by abiotic stress, principal component analysis (PCA) was conducted with five chlorophyll fluorescence variables measured from four varieties. QY_Lss and NPQ_Lss were main chlorophyll fluorescence variables to evaluate abiotic stress, particularly in drought stress. In comparison with transgenic soybean lines based on chlorophyll fluorescence variables, ‘AtMYB44 CM2471’ and ‘AtMYB44 CM4481’ are more tolerant to drought than the others. Interestingly, three transgenic soybean lines which have a same AtMYB44 gene with different regions of chromosome revealed the quite different responses of chlorophyll fluorescence to drought treatment.

We investigated the changes in plasma sex steroid hormones, testosterone (T), estradiol-17β (E2), 17,20 β-dihydroxy-4-pregnen-3-one (17α20βOHP), 11-ketotestosterone (11KT) and cortisol levels from ribbed gunnel, Dictyosoma burgeri in associated with annual reproductive cycle. The fish were collected at the coastal waters of Dadaepo, Busan, Korea from August 2002 to March 2003. Body weight, liver weight and gonad weight were measured for calculation of hepatosomatic index (HSI) and gonadosomatic index (GSI). Plasma steroid and cortisol levels were measured by radioimmunoassay and data were analyzed using the Kruskal-Wallis test and the Spearman rank correlation. The GSI of females increased from November, peaked in February (13.21±2.27) and decreased rapidly from March (1.05±0.23). The GSI of males also increased from November, peaked in December (0.36±0.12) and remained high to February. In females, E2 levels increased and remained high from December to February (19.81±7.46～22.85±6.18 ng/ ㎖). The levels of T showed a similar tendency and correlated (rs=0.813, p=0.0001) significantly with E2 levels. The levels of 17α20βOHP increased rapidly in February (4.78±1.01 ng/㎖) and peaked in July (5.08±0.65 ng/㎖). Cortisol level was peaked in March (2081.07±1140.02 ng/㎖) and correlated significantly with 17α20βOHP levels (rs=0.790, p=0.0001). In males, the levels of T was peaked in January (2.43±0.17 ng/㎖) and then decreased rapidly. The levels of 11KT were remained high from October to January (3.27±1.55～4.28±1.53 ng/㎖) and correlated significantly with T levels (rs=0.513, p=0.002). On the other hand, the levels of 17α20βOHP fluctuated during reproductive cycle and the variation pattern of cortisol levels were similar to females. These results suggest that plasma sex steroids in ribbed gunnels have annual periodicity, and that cortisol may involve in maturation of females.