• 음성과학
• /
• 제13권4호
• /
• pp.69-87
• /
• 2006

This study aims to describe the vowel system of present-day American English and to discuss some of its phonetic variations due to regional differences. Fifteen speakers of American English from various regions of the United States produced the monophthongs of English. The vowel duration and the frequencies of the first and the second formant were measured. The results indicate that the distinction between the vowels [c] and [a] has been merged in most parts of the U.S. except in some speakers from eastern and southeastern parts of the U.S., resulting in the general loss of phonemic distinction between the vowels. The phonemic merger of the two vowels can be interpreted as the result of the relatively small functional load of the [c]-[a] contrast, and the smaller back vowel space in comparison to the front vowel space. The study also shows that the F2 frequencies of the high back vowel [u] were extremely high in most of the speakers from the eastern region of the U.S., resulting in the overall reduction of their acoustic space for high vowels. From the viewpoint of the Adaptive Dispersion Theory proposed by Liljencrants & Lindblom (1972) and Lindblom (1986), the high back vowel [u] appeared to have been fronted in order to satisfy the economy of articulatory gesture to some extent without blurring any contrast between [i] and [u] in the high vowel region.

• 천문학회보
• /
• 제36권1호
• /
• pp.87.2-87.2
• /
• 2011

We report our 110 ks Chandra observations of the supernova remnant (SNR) 0104-72.3 in the Small Magellanic Cloud (SMC). The X-ray morphology shows two prominent lobes along the northwest-southeast direction and a soft faint arc in the east. Previous low resolution X-ray images attributed the unresolved emission from the southeastern lobe to a Be/X-ray star. Our high resolution Chandra data clearly shows that this emission is diffuse, shock-heated plasma, with negligible X-ray emission from the Be star. The eastern arc is positionally coincident with a filament seen in optical and infrared observations. Its X-ray spectrum is well fit by plasma of normal SMC abundances, suggesting that it is from shocked ambient gas. The X-ray spectra of the lobes show overabundant Fe, which is interpreted as emission from the reverse-shocked Fe-rich ejecta. The overall spectral characteristics of the lobes and the arc are similar to those of Type Ia SNRs, and we propose that SNR 0104-72.3 is the first case for a robust candidate Type Ia SNR in the SMC. On the other hand, the remnant appears to be interacting with dense clouds toward the east and to be associated with a nearby star-forming region. These features are unusual for a standard Type Ia SNR. Our results suggest an intriguing possibility that the progenitor of SNR 0104-72.3 might have been a white dwarf of a relatively young population.

• 한국제4기학회지
• /
• 제18권1호통권22호
• /
• pp.41-46
• /
• 2004

영상강 하류 일대에는 여러 단의 하안단구가 발달되어 있다. 본 고에서는 이들 단구 중 현재까지 조사된 해면변동단구성 하안단구를 조사하여, 한반도 남동부 해안의 해안단구 및 해면변동단구와 대비하였다. 영산강 하류지역의 영산 18m 단구는 단구면, 단구구성층의 퇴적상 및 고토양 등의 특성으로 보아 남동부 해안의 최종간빙기 최온난기(MIS) 해성단구 및 해변동단구와 대비된다. 영산 18m 단구의 하상비고는 18m로서 남동부 해안의 최종간빙기 구정선고도와 일치된다.

• Animal cells and systems
• /
• 제14권3호
• /
• pp.197-206
• /
• 2010

The population structure of brown sole was examined in a total of 308 samples collected from three geographical groups: one locality (Gangneung) on the east side of the Korean Peninsula, two localities (Erimo and Tomakomai) on the southeastern side and four localities (Onishika, Teshio, Tomamae and Yoichi) on the northwestern side of Hokkaido Island, Japan, by using sequences of 484 bp from the 5' end of the control region of mtDNA. We detected 225 haplotypes, but 183 of them were unique to an individual. A total of 116 nucleotide sites were variable. Haplotype diversity (h) was very high, ranging from 0.989 to 1.000, and nucleotide diversity (${\pi}$) was detected between 0.015 and 0.022. Genetic distances (${\Phi}_{ST}$) within populations, among populations and among geographical groups were low (0.0002 to 0.0014). No significant difference was detected by the AMOVA test (P < 0.05). Pairwise $F_{ST}$ values between sampling localities were also low and not significant. Genetic differentiation was not detected among sampling localities.

• 수산해양기술연구
• /
• 제14권2호
• /
• pp.113-116
• /
• 1978

우리나라 근해의 열 에너지 이용 가능성을 알기 위하여 황해 동부해역의 연직온도차 분포상황 및 그 계절적 변동을 조사하였고, 이들과 해수유동과의 관련성에 관하여 고찰하였다. 하계에는 거안 약 40mile 해역인 125${\circ}$30'E 이서의 34${\circ}$N이북에 연직온도차가 16$^{\circ}C$ 이상 되는 곳이 존재하는 바, 이것은 따뜻한 황해 난류계수의 표면가열과 저층의 황해냉수에 기인하는 것으로 생각된다. 연안으로 갈수록 연직 온도차는 줄어지고, 거안 약 30mile 해역에서는 약 1$0^{\circ}C$이다. 이를 이용하여 온도차발전이 가능하다고 보아진다. 제주도 남부 및 서부해역은 연직 온도차가 약 14$^{\circ}C$ 이상을 보인다. 겨울에는 왕성한 대류혼합으로 연직 온도차는 거의 없어진다. 그러나 겨울에는 강한 계절풍이 계속 발전체계를 여름에는 온도차발전, 겨울에는 파력 및 풍력발전을 하는 방식으로 체계화하면 주년 계속 발전이 가능할 것이라 생각된다.

• ALGAE
• /
• 제32권3호
• /
• pp.171-179
• /
• 2017

The strictly freshwater red algal order Batrachospermales has undergone numerous taxonomic rearrangements in the recent past to rectify the paraphyly of its largest genus Batrachospermum. These systematic investigations have led to the description of new genera and species as well as re-circumscription of some taxa. Specimens collected from two locations in the southeastern USA were initially identified as being allied to Batrachospermum sensu lato, but could not be assigned to any recognized species. Representative rbcL (plastid) and COI-5P (mitochondrion) sequences showed these specimens to be similar to each other and not closely matching the previously published sequence data for other Batrachospermum taxa. Comparison of sequence variation and morphology with a broader range of batrachospermalean taxa resulted in the proposal of a new monotypic genus Lympha mucosa gen. et sp. nov. to accommodate these specimens. Lympha mucosa is sister to members of a newly described genus Volatus, but the two genera are easily distinguished based on straight versus curved, twisted or spirally coiled carpogonial branch, respectively. This new taxon has morphological similarities to Batrachospermum sections Turfosa and Virescentia, but can be differentiated based on genetic divergence in rbcL and COI-5P as well as a combination of morphological characters: dense, compressed whorls, axial carposporophytes with a single type of gonimoblast filament; cortication of the main axis closely appressed; and short, straight carpogonial branch arising from the pericentral cell and carpogonia with unstalked, lanceolate trichogynes. This new taxon adds to the freshwater red algal diversity of the southeastern USA, a region already known for biodiversity and high endemism of the aquatic flora and fauna. It is also a relevant new addition to the taxonomic knowledge of the freshwater red algal Batrachospermales.

• Parasites, Hosts and Diseases
• /
• 제60권4호
• /
• pp.261-271
• /
• 2022

This study provides an overview of the current status of clonorchiasis and cholangiocarcinoma (CCA), and their relationship in Korea during 2012-2020. Data were obtained from the Health Insurance Review & Assessment Service of Korea. Cluster, trend, and correlation analyses were performed. Gyeongsangnam-do and Seoul had the highest average number of cases (1,026 and 4,208) and adjusted rate (306 and 424) for clonorchiasis and CCA, respectively. The most likely clusters (MLC) for clonorchiasis and CCA were Busan/Gyeongsangnam-do/Ulsan/Daegu/Gyeongsangbuk-do (Relative Risk; RR=4.55, Likelihood Ratio; LLR=9,131.115) joint cluster and Seoul (RR=2.29, LLR=7,602.472), respectively. The MLC for clonorchiasis was in the southeastern part of Korea, while that for CCA was in the southern part. Clonorchiasis showed a decreasing trend in the southeastern districts, while increased in the southwestern districts. Cities in the central region had a decreasing trend, while the western districts had an increasing trend. In most adults (30-59), infection rate of clonorchiasis showed a significant decrease until 2018, while thereafter increased, although not significant. CCA showed a sharply decreasing tendency. The incidence of clonorchiasis and CCA were positively correlated. In general, the correlation was weak (r=0.39, P<0.001), but it was strongly positive around the 4 river basins (r=0.74, P<0.001). This study might provide an analytic basis for developing an effective system against clonorchiasis and CCA.

• 한국지진공학회:학술대회논문집
• /
• 한국지진공학회 2000년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
• /
• pp.70-80
• /
• 2000

In order to reduce seismic hazard the characteristics of strong earthquakes are required. In the region where strong earthquakes do not happen frequently the stochastic simulation of strong motion is an alternative way to predict strong motions. this simulation required input parameters such as the quality factor the corner frequency the moment magnitude the stress drop and so on which can be obtained from analyses of records of small and intermediate earthquakes. Using those parameters obtained in the previous work the strong ground motions are predicted employing the stochastic method, . The results are compared to the two observed earthquakes-the Ulsan Offshore Earthquake and the Kyungju Earthquake. Although some deviations are found the predictions are similar to the observed data. Finally we computed attenuation equations for PGA PGV and ground accelerations for some frequencies using the results of predictions. These results can be used for earthquake engineering and more reliable results will come out as earthquake observations continue.

• 한국자원식물학회지
• /
• 제33권3호
• /
• pp.200-219
• /
• 2020

We performed taxonomic reviews and habitat circumstances survey for 41 un-introduced environmentally harmful plants (as designated by the Ministry of Environment, Korea in 2016). For this purpose, we investigated plant specimens from several herbaria and performed a field survey in the southeastern region of the United States. Base on the result, we presented the most comprehensive results of weed risk evaluation and taxonomic description up to now as well as classification keys for 11 species to apply the regulation management of putative invasive alien species - Centaurea maculosa Lam., Centaurea diffusa Lam., Mikania micrantha Kunth. (Asteraceae), Cenchrus echinatus L., Neyraudia reynaudiana (Kunth) Keng ex Hitchcock, Brachiaria mutica (Forsskål) Stapf, Vulpia bromoides (L.) Gray, Lolium persicum Boissier & Hohennacker, Setaria palmifolia (J. Konig) Stapf (Poaceae), Prosopis glandulosa Torr. (Fabaceae), Fallopia baldschuanica (Regel) Hobub. (Polygonaceae).

• 한국환경과학회지
• /
• 제10권2호
• /
• pp.143-151
• /
• 2001

The atmospheric conditions and the transport mechanism of long-range transport of air pollutants from coastal area to inland area were investigated using regular meteorological data and air pollution data obtatined from the southeastern area of Korea. Daytime temperature over the inland area(Taegu) was higher than that over the coastal area(Pusan) and the temperature difference of about 5~6$^{\circ}C$ when the thermal low most fully developed and the sea level pressure over Taegu was lower than that over Pusan by about 4~5hPa at that time. Therefore this low pressure appeared to the thermally induced low. Air mass polluted from the coastal area during the morning period was transported inland area, at first by the sea breeze and by the large scale wind system toward the thermal low generated in the mountainous inland region. This was explained by the fact that the concentration of air pollutants over Taegu increased throughtout the late afternoon.