• 제목/요약/키워드: natural origin

검색결과 531건 처리시간 0.03초

Search for Faint Quasars at z~5 using Medium-band Observations

  • Shin, Suhyun;Im, Myungshin;Kim, Yongjung;Hyun, Minhee;Jeon, Yiseul;Ji, Tae-Geun;Byeon, Seoyeon;Park, Woojin;Ahn, Hojae;Taak, Yoon Chan;Kim, Sophia;lim, Gu;Hwang, Sungyong;Paek, Insu;Paek, Gregory;Kim, Minjin;Kim, Dohyeong;Kim, Jae-Woo;Yoon, Yongmin;Choi, Changsu;Hong, Jueun;Jun, Hyunsung David;Karouzos, Marios;Kim, Duho;Kim, Ji Hoon;Lee, Seong-Kook;Pak, Soojong;Park, Won-Kee
    • 천문학회보
    • /
    • 제43권2호
    • /
    • pp.36.2-36.2
    • /
    • 2018
  • Cosmic reionization era in the early universe was playing a leading part on making the present universe we know. However, we have not been able to reveal the main contributor to the cosmic reionization to date. Faint quasars have been mentioned as the alternative due to the uncertainty of the faint end slope of the quasars luminosity function. With the availability of the deep (~25mag) images from Subaru Hyper Suprime-Cam (HSC) Strategic Program survey, we have tried to find more quasar with low luminosity in the ELAIS-N1 field. Faint quasar candidates were selected from several multi-band color cut criteria based on the track of the simulated quasar at z ~ 5. The Infrared Medium-deep Survey (IMS) and The UKIRT Infrared Deep Sky Survey (UKIDSS) - Deep Extragalactic Survey (DXS) provide J band information which is used to cover the relatively long wavelength range of quasar spectra. To search the reliable candidates with possible Lyman break, medium-band observation was performed by the SED camera for QUasars in EArly uNiverse(SQUEAN) in the McDonald observatory and Seoul National University 4k Camera(SNUCAM) in the Maidanak observatory. Photometric redshifts of the observed candidates were estimated from chi-square minimization. Also, we predicted the importance of the faint quasar to the cosmic reionization from the expected number density of the faint quasar.

  • PDF

Use of natural ingredients in Japanese quail diet and their effect on carcass and meat quality - A review

  • Vargas-Sanchez, Rey David;Ibarra-Arias, Felix Joel;Torres-Martinez, Brisa del Mar;Sanchez-Escalante, Armida;Torrescano-Urrutia, Gaston Ramon
    • Asian-Australasian Journal of Animal Sciences
    • /
    • 제32권11호
    • /
    • pp.1641-1656
    • /
    • 2019
  • The present paper reviews the findings of different research studies on the effect of natural ingredients in the Japanese quail (Coturnix coturnix japonica) diet on carcass characteristics and meat quality. The results show a relationship between the type and concentration of ingredients used in diets and carcass characteristics and meat quality. The inclusion of medicinal herbs (thyme, black seed, and mint), plants (canola), seeds (chickpea), spices (cinnamon and coriander), worms (earthworms), bee products (propolis), phytochemicals (lycopene), and edible fungi (common mushrooms) in the diet improved carcass quality characteristics compared to the control diets (basal diets). The inclusion of medicinal herbs (spearmint and green tea), spices (cinnamon), vegetables (tomato), plants (verbena and canola), seeds (marijuana), and edible fungi (oyster mushrooms) improved meat quality. In conclusion, the use of ingredients of natural origin in the diet of Japanese quail improves carcass quality characteristics and meat quality.

색도플러 초음파검사에 의한 경추골동맥 기시부 관찰 (Visualization of the Origin of the Vertebral Arteries with Color Doppler Sonography)

  • 윤석환;이원홍;이대형
    • 대한방사선기술학회지:방사선기술과학
    • /
    • 제32권1호
    • /
    • pp.87-93
    • /
    • 2009
  • 배경/목적 : 경추골동맥 기시부의 동맥경화증은 경추기저 국소빈혈증의 위험인자 중 하나이기 때문에 경추골동맥 기시부를 확인해야 할 필요가 있다. 색도플러 초음파검사에 의한 경추골동맥 기시부의 관찰 및 평가는 기술적으로 어려움이 있으며, 특히 왼쪽 기시부는 더욱 그렇다. 이 연구의 목적은 색도플러 초음파검사 시경추골동맥 기시부의 관찰률을 높이는 것이다. 대상 및 방법 : 경동맥을 포함한 경추골동맥의 색도플러 초음파검사가 198명에 대해 시행되었다. 경추골동맥 기시부를 다른 혈관의 기시부와 더 쉽게 구분하기 위해 목 윗부분의 경추동맥에서부터 쇄골하동맥 측으로 검사를 시행하였다. 검사 기술적으로 경추골동맥 기시부가 바로누운자세의 자연스러운 위치에서 관찰되지 않을 경우, 초음파 트랜스듀서를 쇄골 측으로 밀고, 그래도 관찰되지 않을 경우 다른 손으로 어깨를 밀어 관찰을 시도하였다. 경추골동맥 기시부의 깊이와 위 세 가지 방법 및 그에 따른 관찰률을 확인하기 위하여, 검사된 초음파 영상에서 관찰된 경추골동맥 기시부의 위치를 3.0 cm 이하와 그 이상으로 구분하였다. 결 과 : 오른쪽 경추골동맥 기시부는 97%, 왼쪽 경추골동맥 기시부는 92%에서 관찰되었다. 3.0 cm 이하에서 관찰된 오른쪽 경추골동맥 기시부 중 자연스러운 자세, 트랜스듀서 밀기, 그리고 어깨 밀기에서 관찰된 경우는 각각 98.6%, 1.4%, 그리고 0.0%이었다. 그리고 3.0 cm 보다 더 깊은 위치에서 관찰된 오른쪽 경추골동맥 기시부 중 자연스러운 자세, 트랜스듀서 밀기, 그리고 어깨 밀기에서 관찰된 경우는 각각 81.2%, 14.6%, 그리고 4.2%이었다. 3.0 cm 이하에서 관찰된 왼쪽쪽 경추골동맥 기시부 중 자연스러운 자세, 트랜스듀서 밀기, 그리고 어깨 밀기에서 관찰된 경우는 각각 85.4%, 10.7%, 그리고 3.9%%이었다. 그리고 3.0 cm 보다 더 깊은 위치에서 관찰된 오른쪽 경추골동맥 기시부 중 자연스러운 자세, 트랜스듀서 밀기, 그리고 어깨 밀기에서 관찰된 경우는 각각 55.7%, 30.4%, 그리고 13.9%이었다. 결 론 : 경추골동맥의 색도플러 초음파검사에서 그 기시부가 바로누운자세의 자연스러운 위치에서 관찰되지 않을 경우, 초음파 트랜스듀서를 쇄골 측으로 밀거나 그래도 관찰되지 않을 경우 다른 손으로 어깨를 밀어 관찰을 시도한다면, 관찰률을 좀더 높일 수 있을 것으로 사료된다.

  • PDF

칸트 도덕철학의 자율적 자유 개념의 루소적 기원 (Rousseauistic origin of Kant's theory of Freedom.)

  • 문성학
    • 철학연구
    • /
    • 제116권
    • /
    • pp.79-110
    • /
    • 2010
  • 필자는 이 논문에서 칸트 도덕철학에서의 자율적 자유 개념의 루소적 기원에 대해 고찰하고자 한다. 칸트가 자신의 자율적 자유 개념을 형성함에 있어서 그리고 자유를 자기 철학체계의 요석으로 간주함에 있어서 루소로부터 영향을 받았음이 사실이라 하더라도, 루소 자유론의 어떤 측면이 칸트 자유론의 어느 부분에 영향을 주었는가에 대해서는 아직 세부적인 연구가 이루어 지지 않았다. 필자가 주목하고자 하는 부분이 바로 이것이다. 필자는 먼저 루소가 인간의 본성을 자유로 보았음을 살펴볼 것이다. 둘째로 루소의 세 가지 자유 개념을 고찰할 것이다. 루소는 자연적 자유, 시민적 자유, 도덕적 자유에 대해 고찰한다. 셋째로 칸트가 언급하는 다양한 자유 개념들을, 즉 선험적 자유, 실천적 자유, 자율적 자유의 개념들을 간략히 살펴본 뒤, 이 세 가지 자유 개념의 공통적인 요소가 자발성, 자기입법성, 보편성임을 밝힐 것이다. 마지막으로 그 세 가지 요소의 루소적 기원을 살펴보는 방식으로, 루소의 자유 개념을 해명하고자 한다. 보다 세부적으로 말한다면, 칸트는 루소의 자연적 자유 개념으로부터 의지의 자발성의 요소를, 루소가 말하는 시민적 자유의 개념으로부터 자기입법성을, 루소가 말하는 도덕적 자유의 개념으로부터 보편성을 받아들였음을 밝히고자 한다.

조선왕조실록 갈피에서 발견된 잎 조각의 실체 및 천궁의 식물학적 기원 (Taxonomic Identity of Leaf Fragments Found in the Annals of the Joseon Dynasty and Botanical Origin of a Herbal Medicine 'Cheongung')

  • 서영배;김영식;이채민;박지수;고혜진;이상찬;정진숙;최호영
    • 생약학회지
    • /
    • 제47권2호
    • /
    • pp.128-136
    • /
    • 2016
  • Tiny leaf fragments were found in the Annals of the Joseon Dynasty, which were compiled about 500 years ago. The records describing the detailed process of compiling the Annals indicate that silk bags packed with the powders of 'Cheongung' and 'Changpo', which have been used as traditional herbal medicines in the northeast Asian countries such as China and Japan as well as Korea, were put in the wooden storage boxes together with the volumes of the Annals. However, there is no record that parts of plants were used in the process of compiling the Annals. The botanical origin of leaf fragments was identified as Ligusticum sinense 'Chuanxiong' by the analysis of trnK of chloroplast DNA as well as the examination of leaf surface with SEM. The comparative analysis of trnK sequences showed that the chloroplast DNA haplotype of 'Tocheongung', a triploid species cultivated in Korea, was identical with Cnidium officinale, but different from L. sinense 'Chuanxiong'. The molecular results provide a new suggestion on the botanical origin of crude drugs used as 'Cheongung', which has been disputed in Korea.

Survey of Faint Quasar candidates at 4.7 ≤ z ≤ 5.2

  • Shin, Suhyun;Im, Myungshin;Kim, Yongjung;Hyun, Minhee;Park, Woojin;Ji, Tae-geun;Jeon, Yiseul;Kim, Minjin;Kim, Dohyeong;Kim, Jae-Woo;Taak, Yoon Chan;Yoon, Yongmin;Choi, Changsu;Hong, Jueun;Jun, Hyunsung David;Karouzos, Marios;Kim, Duho;Kim, Ji Hoon;Lee, Seong-Kook;Pak, Soojong;Park, Won-Kee
    • 천문학회보
    • /
    • 제43권1호
    • /
    • pp.59.4-60
    • /
    • 2018
  • To investigate the impact of the high-redshift quasars on cosmic reionization, the faint end slope of the quasars luminosity function has to be determined precisely. More quasars with low luminosity are needed to constrain the contribution to reionization in the early universe. However, finding these quasars has been regarded as tough process owing to the improper shallow depth of imaging data. In recent days, the release data of Subaru Hyper Suprime-Cam (HSC) Strategic Program survey which provide the deep images reaching ~ 25 mag facilitates searching the faint quasars candidates. To find faint quasar candidates in ELAIS-N1 field, along with the HSC data, two near-infrared (NIR) data sets also be used : The Infrared Medium-deep Survey (IMS) and The UKIRT Infrared Deep Sky Survey (UKIDSS) - Deep Extragalactic Survey (DXS). Quasar candidates selected from the multi-band color cut were observed by the SED camera for QUasars in EArly uNiverse (SQUEAN) instrument. To trace the redshifted Lyman break efficiently, appropriate medium bands comparable to targeted redshift range are chosen. The most reliable quasar candidates are finally determined through SED fitting. Using this less luminous quasars candidates, we can speculate the relation between the quasar growth and the host galaxy unbiasedly and estimate the contribution to the cosmic reionization.

  • PDF

Cloning of Autonomously Replicating Sequence from Phaffia rhodzyma

  • Chun, Soon Bai;Seung Hee Chun
    • Journal of Microbiology and Biotechnology
    • /
    • 제5권6호
    • /
    • pp.370-372
    • /
    • 1995
  • A Phaffia rhodozyma chromosomal fragment (approximately 3.8 kb) capable of functioning as an origin for the replication of a kanamycin resistance ($Km^r$) plasmid in S. cerevisiae was isolated by the use of origin search plasmid, pHN134. In S. cerevisiae, transformation frequencies using the plasmid pHN134 containing an autonomously replicating sequence of P. rhodozyma was 450-580 CFU/$\mu g$ DNA. The stability of the recombinant plasmid were 16-19$\%$.

  • PDF

과학기술정책의 기원 (The Origins of Science and Technology Policy)

  • 설성수
    • 기술혁신연구
    • /
    • 제5권1호
    • /
    • pp.113-149
    • /
    • 1997
  • This paper, searching for the origin of the science and technology policy, is one of the research series on the original form of current S&T policy such as origin, evolution and changing patterns. Without understanding the origin, it is very difficult to understand the evolution and the current change of the policy. To answer this question, 2 kinds of conditions are set: 4 concepts for the origin of a policy and also 4 conditions for the S&T policy itself. As the origin of a policy, 4 concepts are set such as independence, continuance, diffusion and modern state as a policy body. Also as conditions for S&T policy, there may be 4 conditions such as policy targets, policy functions, administration body and the usage of the name of the policy. S&T can be distinguished as science, technology and S&T along it's development path. There, hence, are 2 origins of science and technology policy. French policy for modern science at the late 18th century and the establishment of the Agency of Science and Technology Policy of Japan in 1956 can be pointed out as the origin of the policy. The former can be called as the origin for natural science, and the latter as the origin for S&T. This study implies that new paradigm of S&T policy is a reflection for both the needs of new S&T and social needs. When there were big problems in a society and when there appeared new S&T, they exploited new S&T vigorously. This has been remained as a rememberable monuments in the history of the S&T policy.

  • PDF

The Origin of the Metal-insulator Transitions in Non-stoichiometric TlCu3-xS2 and α-BaCu2-xS2

  • Jung, Dong-woon;Choi, Hyun-Guk;Kim, Han-jin
    • Bulletin of the Korean Chemical Society
    • /
    • 제27권3호
    • /
    • pp.363-367
    • /
    • 2006
  • The structure-property relations of ternary copper chalcogenides, $TlCu_{3-x}S_2$ and $\alpha-BaCu_{2-x}S_2$ are examined. The density of states, band dispersions, and Fermi surfaces of these compounds are investigated to verify the reason of the metal-insulator transitions by extended Huckel tight-binding band calculations. The origin of the metalinsulator transitions of non-stoichiometric $TlCu_{3-x}S_2$ and $\alpha-BaCu_{2-x}S_2$ is thought to be the electronic instability induced by their Fermi surface nesting.