68 research outputs found
๋ธ๋ ์ด์ ๋ค์ ์ ํ/๊ฐ๋ง์ ์๊ด๊ด๊ณ
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ผ๋ฌธ(๋ฐ์ฌ) -- ์์ธ๋ํ๊ต๋ํ์ : ์์ฐ๊ณผํ๋ํ ๋ฌผ๋ฆฌยท์ฒ๋ฌธํ๋ถ(์ฒ๋ฌธํ์ ๊ณต), 2021.8. Sascha Trippe.Relativistic jets in Active Galactic Nuclei (AGN) are one of the most powerful, persistent
sources of energy in the Universe. Investigation of AGN jets is valuable and promising as they
play an important role in not only the fields of high-energy astrophysics, but also the evolution
of galaxies and clusters. Radio-loud AGNs with their relativistic jets directed toward us (e.g.,
with a viewing angle of โผ5 degrees), are classified as blazars. One of the well-known characteristics of
blazars is strong ฮณ-ray emission originating from their relativistic jets. Because the spatial res-
olution of high-energy telescopes is inadequate, however, our understanding of the high-energy
emission is limited and thus the production site of blazar ฮณ-ray flares is a matter of active de-
bate. To explore the high-energy emission processes and its origin, I studied several individual
blazars that recently showed strong ฮณ-ray emission: BL Lacertae, OT 081 (1749+096), 3C 273,
and 0716+714. In these studies, I analyzed their multi-wavelength (radio-to-ฮณ-ray) light curves
and Very Long Baseline Interferometry (VLBI) datasets on both the time-domain and image-
plane to investigate the variations in emission, structure, and kinematics of the jets during a
number of ฮณ-ray flaring periods.
The blazar BL Lacertae which is the prototypical BL Lac object (a subclass of blazar), was
explored using VLBI datasets obtained from the Korean VLBI Network (KVN). Properties
of the radio jet are presented with light curves of the radio core (i.e., the VLBI core seen
by the KVN) at 22, 43, 86, and 129 GHz. Our observations covered the decaying part of a
strong radio flare. The timescales (ฯ) of the exponential decays show the following relationship:
ฯ โ ฮฝโ0.2 , with ฮฝ being observing frequency. This is much shallower than the one expected
from opacity effects (i.e., the core shift). Simultanous multi-frequency observations of the KVN
allow us to perform spectral analysis of the radio emission. The spectral indices versus time
and radio frequency, support the models of recollimation shocks (Marscher et al. 2008) and the
generalized shock evolution (Valtaoja et al. 1992).
OT 081 is a blazar with a compact radio jet. In many VLBI images, the source shows
a simple point-like feature without any notable extended structures. It had been consistently
bright at radio wavelengths (e.g., a few Jy), but without noteworthy strong ฮณ-ray outbursts. However, there was a historically strong ฮณ-ray outburst in 2016 in this source. To investigate
this phenomenon, multi-waveband data were used: KVN and OVRO (radio), ASAS-SN (opti-
cal), Swift-XRT (X-ray), and Fermi-LAT (ฮณ-ray). It was revealed that the 2016 ฮณ-ray outburst
is highly correlated with emission at lower frequencies from radio to X-ray. By using VLBA
observations, we found that this ฮณ-ray event was accompanied by the emergence of a moving
polarized knot from the radio core which propagates further downstream of the flow. Combin-
ing all the evidence, we conclude that the radio core is the origin of the ฮณ-ray outburst.
Blazars can be divided into two subclasses: flat-spectrum radio quasars (FSRQ) and BL Lac
objects, based on the presence/absence of broad optical emission lines. Recent studies sup-
ported that ฮณ-rays of FSRQs originate from a region beyond the broad-line region (BLR), sug-
gesting distances of a few parsecs from the central engine where the radio core is thought to
be located. Motivated by this, I investigated two recent ฮณ-ray outbursts of the FSRQ 3C 273
which is one of the most powerful and famous blazars. Analysis were done with data obtained
from the ALMA, VLBA, and Fermi-LAT. In order to check the correlation between radio and
ฮณ-ray emission, the discrete correlation function (DCF) was employed. Our results indicate
that the compact features (i.e., multiple standing shocks) are responsible for the observed ฮณ-ray
outbursts in the jet of 3C 273.
0716+714 is known to have extreme variability over the entire electromagnetic spectrum.
Our preliminary findings of an unusual anti-correlation between radio and ฮณ-ray emission in
this source, lead us to start a detailed study of the radio/ฮณ-ray connection in the jet of 0716+714.
Archival multi-frequency data (i.e., SMA, Metsรคhovi, OVRO, Fermi-LAT, and VLBA) were
employed and the correlation analysis between the datasets was performed using the techniques
of modeling and simulating the light curves. As a result, we found three significant radio-to-
ฮณ-ray correlations: two anti-correlations and one positive correlation. We also analyzed VLBA
datasets to investigate the parsec-scale jet activity during the ฮณ-ray flares. With all the evidence,
we constrain the origin of the ฮณ-ray flares in the jet and suggest internal-shock interactions
induced by the passage of a moving disturbance through the radio core as the mechanism
behind the observed correlated behaviors.
Physics of the relativistic jets in blazars is tricky and complicated due to the extreme physical conditions and various scenarios/possibilities. More detailed observations of the jets with
high-resolution VLBI arrays, are currently the best way to resolve the issues of the jet physics.
This thesis presents new observational data and results on the nature of blazar ฮณ-ray flares and
contributes to the scientific community by supplying the wealth of information for the cases
of four remarkable blazars. The individual studies presented in this thesis, conclude as follow:
(1) blazar ฮณ-ray flares have multiple emission regions in the jets (i.e., subpc/pc-scales distances
from the central black hole) and (2) the propagation of shocks/disturbances along the jet in the
subpc/pc-scale regions, causes ฮณ-ray flares (particularly when they pass through the standing
shock features; e.g., the radio core).ํ๋์ฑ์ํํต (AGN)๋ค์ ์๋๋ก ์ ์ ํธ๋ ์ฐ์ฃผ์์ ๊ฐ์ฅ ๊ฐ๋ ฅํ๋ฉฐ ์์์ ์ธ ์๋์ง ์์ค๋ค ์ค์ ํ๋์ด๋ค. ๊ณ ์๋์ง ์ฒ์ฒด๋ฌผ๋ฆฌ๋ถ์ผ ๋ฟ๋ง ์๋๋ผ ์ํ์ ์ฑ๋จ์ ์งํ์ ์ค์ํ ์ญํ ์ ํจ์ ๋ฐ๋ผ, AGN ์ ํธ๋ค์ ๋ํ ์ฐ๊ตฌ๋ ๊ฐ์น์์ผ๋ฉฐ ์ ๋์ ๋งํ๋ค. ์ ํ์์ ๋ฐ์ AGN (radio-loud AGN)๋ค ์ค, ๊ทธ๋ค์ ์ ํธ๊ฐ ๋ป์ด๋๊ฐ๋ ์ถ๊ณผ ์ฐ๋ฆฌ์ ์์ ๋ฐฉํฅ ์ฌ์ด์ ๊ฐ๋๊ฐ ๋งค์ฐ ์์ (์ฝ 5๋ ์ด๋ด) AGN๋ค์ ๋ธ๋ ์ด์ (Blazar)๋ก์จ ๋ถ๋ฅ๋๋ค. Blazar๋ค์ ๋ํ์ ์ธ ํน์ง ์ค ํ๋๋ ๊ทธ๋ค์ ์ ํธ๋ก๋ถํฐ ๋์ค๋ ๊ฐ๋ ฅํ ๊ฐ๋ง์ ๋ฐฉ์ถ์ด๋ค. ํ์ง๋ง ๊ณ ์๋์ง ๋ง์๊ฒฝ๋ค์ ๊ณต๊ฐ๋ถํด๋ฅ์ด ์ถฉ๋ถํ์ง ๋ชปํ๊ธฐ ๋๋ฌธ์, ๊ทธ๋ฌํ ๊ณ ์๋์ง ๋น ๋ฐฉ์ถ์ ๋ํ ์ฐ๋ฆฌ์ ์ดํด๋ ์ ํ๋์ด ์๊ณ , ์ด์ ๋ฐ๋ผ Blazar ๊ฐ๋ง์ ํญ๋ฐ์ ๊ธฐ์์ ํ์ฌ ํ๋ฐํ ๋
ผ์ ์ค์ ์๋ค. ๊ทธ๋ฌํ ๊ณ ์๋์ง ๋น์ ๋ฐฉ์ถ๊ธฐ์๊ณผ ๊ธฐ์์ ํ๊ตฌํ๊ธฐ ์ํด์, ๋ณธ ์ ์๋ ์ต๊ทผ ๊ฐํ ๊ฐ๋ง์ ๋ฐฉ์ถ์ ๋ณด์ธ ๋ช ๊ฐ์ ๊ฐ๋ณ Blazar๋ค์ ์ฐ๊ตฌํ์๋ค: BL Lacertae, OT 081 (1749+096), 3C 273, ๊ทธ๋ฆฌ๊ณ 0716+714. ์ด ์ฐ๊ตฌ๋ค์์ ๋ณธ ์ ์๋ ๊ฐ๋ง์ ํญ๋ฐ ๊ธฐ๊ฐ ๋์์ ์ ํธ๋ค์ ๋น, ๊ตฌ์กฐ, ๊ทธ๋ฆฌ๊ณ ์ด๋ํ์ด ์ด๋ป๊ฒ ๋ณํํ๋์ง๋ฅผ ์กฐ์ฌํ์์ผ๋ฉฐ, ์ด๋ฅผ ์ํด ๊ทธ๋ค์ ๋คํ์ฅ (์ ํ-๊ฐ๋ง์ ) ๋ณ๊ด๊ณก์ ๋ฐ ์ต์ฅ๊ธฐ์ ๊ฐ์ญ๊ณ (VLBI) ๋ฐ์ดํฐ๋ค์ ์๊ฐ๋๋ฉ์ธ๊ณผ ์ด๋ฏธ์ง๋ฉด ์์์ ๋ถ์ํ์๋ค.
Blazar์ ํ ์ ํ์ธ BL Lac object์ ์ํ๋ฉฐ, ๋ํ ํด๋น ํ์
์ ์ํ์ด๊ธฐ๋ ํ BL Lacertae๊ฐ ํ๊ตญ VLBI ๊ด์ธก๊ธฐ์ธ KVN๋ฅผ ์ด์ฉํด ์ฐ๊ตฌ๋์ด์ก๋ค. 22, 43, 86, ๊ทธ๋ฆฌ๊ณ 129 GHz์์ ์ป์ด์ง ์ ํ์ฝ์ด์ ๋ณ๊ด๊ณก์ ์ ์ด์ฉํ์ฌ ์ป์ด์ง ์ ํธ์ ํน์ฑ๋ค์ด ๋ํ๋ด์ด์ก๋ค. ์ฐ๋ฆฌ์ ๊ด์ธก๋ฐ์ดํฐ๋ ํ๋์ ๊ฐ๋ ฅํ ์ ํ ํญ๋ฐ์ ๊ฐ์ ๋ถ๋ถ์ ํฌํจํ๋ค. ์ง์ํจ์์ ๊ฐ์์ ์๊ฐ๊ท๋ชจ (tau) ๋ค์ ๋ค์์ ๊ด๊ณ์์ ๋ฐ๋ฅธ๋ค: tau ๋น๋ก nu^-0.2, nu๋ ๊ด์ธก์ฃผํ์๋ฅผ ๋ํ๋ธ๋ค. ์ด๋ ๋ถํฌ๋ช
๋ ํจ๊ณผ (Core shift)๋ก๋ถํฐ ์์๋๋ ๊ฒฐ๊ณผ์ ๋นํด ๋งค์ฐ ์๋ค. KVN์ ๋ค์ฃผํ์ ๋์๊ด์ธก์ ์ ํ ๋ฐฉ์ถ ๋น์ ๋ํ ๋ถ๊ดํ์ ๋ถ์์ ๊ฐ๋ฅํ๊ฒ ํด์ค๋ค. ์๊ฐ๊ณผ ์ ํ ์ฃผํ์์ ๋ํ ๋ถ๊ด์ง์ (Spectral index)์ ๋ณํ๋ Recollimation shock ๋ชจ๋ธ๊ณผ Generalized shock ๋ชจ๋ธ๋ค์ ์ง์งํ๋ค.
OT 081์ ์กฐ๋ฐํ๊ณ ์ํ์ธ ์ ํธ๋ฅผ ์ง๋ Blazar์ด๋ค. ๋ง์ VLBI ์ด๋ฏธ์ง๋ค์์ ํด๋น ์ ํธ๋ ๋ฐ๊นฅ์ชฝ์ผ๋ก ์ฐ์ฅ๋ ๋์ ๋๋ ๊ตฌ์กฐ๋ค ์์ด ๋จ์ํ ํฌ์ธํธ์ ๊ฐ์ ํํ์ ๊ตฌ์กฐ๋ฅผ ๋ณด์ฌ์ค๋ค. ์ด ์์ค๋ ์ฃผ๋ชฉํ ๋งํ ๊ฐ๋ง์ ํญ๋ฐ์์ด ์ ํ์์ ์ง์์ ์ผ๋ก ๋ฐ์์์๋ค. ๊ทธ๋ฌ๋ 2016๋
๋์ ์ด ํ๊ฒ์์ค์ ๋ํด์ ์ญ์ฌ์ ์ผ๋ก ๊ฐ๋ ฅํ ๊ฐ๋ง์ ํญ๋ฐ์ด ๋ฐ์ํ์์๋ค. ์ด ํ์์ ์กฐ์ฌํ๊ธฐ ์ํด, ๋คํ์ฅ ๋ฐ์ดํฐ๋ค์ด ์ฌ์ฉ๋์๋ค: KVN๊ณผ OVRO (์ ํ), ASAS-SN (๊ดํ), Swift-XRT (์์ค์ ), ๊ทธ๋ฆฌ๊ณ Fermi-LAT (๊ฐ๋ง์ ). 2016 ๊ฐ๋ง์ ํญ๋ฐ์ด ๋ฎ์ ์ฃผํ์๋ (์ ํ๋ถํฐ ์์ค์ ๊น์ง)์ ๋ฐฉ์ถ ๋น๋ค๊ณผ ์๋นํ ์๊ด๊ด๊ณ๋ฅผ ๊ฐ์ง๊ณ ์์์ด ๋๋ฌ๋ฌ๋ค. VLBA ๊ด์ธก๋ฐ์ดํฐ๋ฅผ ์ด์ฉํจ์ผ๋ก์จ, ์ฐ๋ฆฌ๋ ๋ํ ์ด ๊ฐ๋ง์ ํญ๋ฐ์ด ์ ํ์ฝ์ด๋ก๋ถํฐ ๋์ ์ ํธ์ ํ๋ฅ๋ก ์ ํ/์ด๋ํด๋๊ฐ๋ ํธ๊ด ์ปดํฌ๋ํธ (Knot)์ ์ถํ์ ์๋ฐํ์์์ ์ฐพ์๋ค. ์ด๋ฌํ ๋ชจ๋ ์ฆ๊ฑฐ๋ค์ ์กฐํฉํด๋ด์ผ๋ก์จ, ์ฐ๋ฆฌ๋ ์ ํ์ฝ์ด๊ฐ ๊ฐ๋ง์ ํญ๋ฐ์ ๊ธฐ์์ด๋ผ ๊ฒฐ๋ก ์ง์๋ค.
Blazar๋ค์ ๋ ๊ฐ์ง ์ ํ์ผ๋ก ๋๋์ด ์ง ์ ์๋ค: ๋์ ๊ดํ ๋ฐฉ์ถ์ ์ ์กด์ฌ/๋ถ์ฌ์ ๋ฐ๋ผ, Flat-Spectrum Radio Quasar (FSRQ) ๊ทธ๋ฆฌ๊ณ BL Lac object. ๊ทผ๋์ ์ฐ๊ตฌ๊ฒฐ๊ณผ๋ค์ FSRQ๋ค๋ก๋ถํฐ ๋์ค๋ ๊ฐ๋ง์ ๋ค์ด Broad-Line Region (BLR) ๋๋จธ์ ์ง์ญ์์ ๊ธฐ์ํจ์ ์์ฌํ์๋ค. ์ด๋ ์ ํ์ฝ์ด๊ฐ ์์นํด ์์ ๊ฒ์ผ๋ก ์ฌ๊ฒจ์ง๋, ์ค์์ ๋ธ๋ํ๋ก๋ถํฐ ๋ช ํ์น (parsec) ๋จ์ด์ง ๊ฑฐ๋ฆฌ๋ฅผ ์์ํ๋ค. ์ด๋ฌํ ์์ด๋์ด์ ์ฐฉ์ํ์ฌ, ๋ณธ ์ ์๋ ๊ฐ์ฅ ๊ฐํ๋ฉฐ ์ ๋ช
ํ Blazar๋ค ์ค ํ๋์ธ 3C 273 (FSRQ)๋ก๋ถํฐ ๋ฐ์ํ ์ต๊ทผ์ ๋ ๊ฐ๋ง์ ํญ๋ฐ๋ค์ ์กฐ์ฌํ์๋ค. ๋ถ์์ ALMA, VLBA, ๊ทธ๋ฆฌ๊ณ Fermi-LAT ๋ฐ์ดํฐ๋ค์ ์ด์ฉํ์ฌ ์ํ๋์ด์ก๋ค. ์ ํ์ ๊ฐ๋ง์ ๋ณ๊ด๊ณก์ ์ฌ์ด์ ์๊ด๊ด๊ณ๋ฅผ ์์๋ณด๊ธฐ ์ํด, Discrete Correlation Function (DCF)๊ฐ ์ฌ์ฉ๋์๋ค. ์ฐ๋ฆฌ์ ๊ฒฐ๊ณผ๋ค์ ๋งค์ฐ ์กฐ๋ฐํ Multiple standing shock๋ค์ด 3C 273์ ์ ํธ ์์์ ๊ด์ธก๋ ๊ฐ๋ง์ ํญ๋ฐ๋ค์ ๊ธฐ์์์ ๋ํ๋ธ๋ค.
0716+714๋ ๋ชจ๋ ์ ์๊ธฐํ ์์ญ์์ ๊ทน์ ์ธ ๋ณ๊ด์ฑ์ ๋ณด์ด๋ ๊ฒ์ผ๋ก ์๋ ค์ ธ ์๋ค. ์ฐ๋ฆฌ์ ์ฌ์ ์กฐ์ฌ๊ฒฐ๊ณผ๋ก ๋ฐํ์ง ํด๋น ์์ค์์์ ์ ํ์ ๊ฐ๋ง์ ๋ฐฉ์ถ ๋น ์ฌ์ด์ ์ญ์๊ด๊ด๊ณ (anti-correlation)๋ ์ฐ๋ฆฌ๊ฐ 0716+714 ์ ํธ ์์์ ์ ํ/๊ฐ๋ง์ ์ฐ๊ด์ฑ์ ๋ํ ์์ธํ ์ฐ๊ตฌ๋ฅผ ๊ฐ์ํ๊ฒ ๋๋ ๋๊ธฐ๊ฐ ๋์๋ค. ๊ธฐ๋ก ๋ณด๊ด๋ (archival) ๋คํ์ฅ ๋ฐ์ดํฐ๋ค (SMA, Metsahovi, OVRO, Fermi-LAT, ๊ทธ๋ฆฌ๊ณ VLBA)์ด ์ฌ์ฉ๋์์ผ๋ฉฐ, ๋ฐ์ดํฐ๋ค ๊ฐ์ ์๊ด๊ด๊ณ ๋ถ์์ ๋ณ๊ด๊ณก์ ๋ค์ ๋ชจ๋ธ๋ง๊ณผ ์๋ฎฌ๋ ์ด์
์ ์ด์ฉํด ์ํ๋์ด์ก๋ค. ๊ทธ ๊ฒฐ๊ณผ, ์ฐ๋ฆฌ๋ ์ธ ๊ฐ์ ์ค๋ํ ์ ํ/๊ฐ๋ง์ ์๊ด๊ด๊ณ๋ฅผ ์ฐพ์๋ค: ๋ ๊ฐ์ ์ญ์๊ด๊ด๊ณ๋ค๊ณผ ํ๋์ ์์ ์๊ด๊ด๊ณ. ์ฐ๋ฆฌ๋ ๋ํ ๊ฐ๋ง์ ํญ๋ฐ๋ค์ด ๋ฐ์ํ๋ ๋์ ํ์น ๊ท๋ชจ์์์ ์ ํธ๊ฐ ์ด๋ ํ ํ๋์ฑ์ ๋ณด์ด๋์ง๋ฅผ ์์๋ณด๊ธฐ ์ํด VLBA ๋ฐ์ดํฐ๋ฅผ ๋ถ์ํ์๋ค. ๊ฒฐ๊ณผ๋ค๋ก๋ถํฐ ์ป์ด์ง ๋ชจ๋ ์ฆ๊ฑฐ๋ฅผ ํ ๋๋ก ์ฐ๋ฆฌ๋ ์ ํธ ๋ด์์ ๊ฐ๋ง์ ํญ๋ฐ๋ค์ ๊ธฐ์์ ํ์ ํ๊ณ , ๊ด์ธก๋ ์๊ด๊ด๊ณ๋ค์ ๋ฐฐ๊ฒฝ๊ธฐ์์ผ๋ก์จ ์ด๋ํ๋ ์ญ๋์ด ์ ํ์ฝ์ด๋ฅผ ์ง๋๋ฉด์ ์ ๋ฐ๋๋ Internal-shock interaction์ ์ ์ํ๋ค.
๊ทน์ ์ธ ๋ฌผ๋ฆฌ์ ์ํ์ ๋ค์ํ ์๋๋ฆฌ์ค ๋ฐ ๊ฐ๋ฅ์ฑ๋ค ๋๋ฌธ์, Blazar์ ์๋๋ก ์ ์ ํธ๋ค์ ๋ํ ๋ฌผ๋ฆฌ๋ ๋ณต์กํ๋ฉฐ ๊น๋ค๋กญ๋ค. ๊ณ ๋ถํด๋ฅ VLBI ์ด๋ ์ด๋ค์ ํตํ ์ ํธ์ ์์ธํ ๊ด์ธก์ ํ์ฌ ์ ํธ๋ฌผ๋ฆฌ์์์ ์์ ๋ค์ ํด๊ฒฐํ ๊ฐ์ฅ ์ข์ ๋ฐฉ๋ฒ์ด๋ค. ๋ณธ ํ์๋
ผ๋ฌธ์ Blazar ๊ฐ๋ง์ ํญ๋ฐ๋ค์ ํน์ฑ์ ๋ํ ์๋ก์ด ๊ด์ธก์ ๋ฐ์ดํฐ์ ๊ฒฐ๊ณผ๋ค์ ๋ณด์ฌ์ฃผ๋ฉฐ, 4๊ฐ์ ์ฃผ๋ชฉํ ๋งํ Blazar๋ค์ ๊ฒฝ์ฐ๋ค์ ๋ํ์ฌ ํ๋ถํ ์ ๋ณด๋ฅผ ์ ๊ณตํจ์ผ๋ก์จ ํ๊ณ์ ๊ธฐ์ฌํ๋ค. ๋ณธ ํ์๋
ผ๋ฌธ์ ์๋ก๋ ๊ฐ๋ณ ์ฐ๊ตฌ๋ค์ ๋ค์๊ณผ ๊ฐ์ ๊ฒฐ๋ก ์ ๋ด๋ฆฐ๋ค: (1) Blazar์ ๊ฐ๋ง์ ํญ๋ฐ๋ค์ ์ ํธ ๋ด์์ ๋ค์ค ๋ฐฉ์ถ ์์ญ์ ๊ฐ์ง๋ค (์ค์ ๋ธ๋ํ๋ก๋ถํฐ subpc/pc ๊ท๋ชจ์ ๊ฑฐ๋ฆฌ) ๊ทธ๋ฆฌ๊ณ (2) subpc/pc ๊ท๋ชจ์ ๊ฑฐ๋ฆฌ์์ ์ ํธ์ ํ๋ฅ๋ฅผ ๋ฐ๋ผ ์ ํํด๋๊ฐ๋ Shock/์ญ๋๋ค์ ์ด๋์ด ๊ฐ๋ง์ ํญ๋ฐ์ ์ ๋ฐํ๋ค (ํน๋ณํ ๊ทธ๋ค์ด Standing shock ๊ตฌ์กฐ๋ค์ ์ง๋๊ฐ ๋).I. Introduction 1
1.1 Radio jets in Active Galactic Nuclei (AGN) 1
1.1.1 Active Galactic Nuclei 1
1.1.2 Formation of AGN jets 3
1.1.3 Jet structures and evolution 6
1.1.4 Beaming effects 13
1.1.5 Importance in astrophysics 16
1.2 Multi-waveband observations of AGN 18
1.2.1 Very Long Baseline Interferometry 18
1.2.2 Fermi-LAT 25
1.3 High energy gamma-ray emission in blazars 28
1.3.1 Nonthermal emission 28
1.3.2 The radio/ฮณ-ray connection 32
1.4 Thesis outline 37
II. The Millimeter-Radio Emission of BL Lacertae During Two ฮณ-Ray Outbursts 39
2.1 Introduction 40
2.2 Observation and Data reduction 41
2.3 Results 45
2.3.1 Radio morphology of BL Lac seen by the KVN 46
2.3.2 Radio Light Curves 48
2.3.3 Spectral Indices and Spectrum of the Core 51
2.4 Discussion 53
2.4.1 Variability and Cooling Time Scales 55
2.4.2 Shock Evolution in The Core Region 59
2.4.3 The Radio-ฮณ-Ray Connection 60
2.5 Summary 63
III. Exploring The Nature of The 2016 ฮณ-Ray Emission in The Blazar 1749+096 65
3.1 Introduction 66
3.2 Observations and Data 67
3.2.1 KVN 22/43/86/129 GHz & VLBA 43 GHz 67
3.2.2 OVRO 15 GHz 68
3.2.3 ASAS-SN 69
3.2.4 Swift-XRT 69
3.2.5 Fermi-LAT 69
3.3 Results and Analysis 71
3.3.1 Multi-waveband light curves 71
3.3.2 Multi-wavelength flux correlations 72
3.3.3 LAT ฮณ-ray photon indices 75
3.3.4 Linear polarization at 43 GHz 77
3.3.5 Flux evolution near the core 79
3.4 Discussion 82
3.4.1 ฮณ-ray activity 82
3.4.2 Multi-wavelength correlations 83
3.4.3 Origin of the ฮณ-ray outburst 83
3.4.4 The enhanced ฮณ-ray emission in 2016 October 86
3.5 Summary 86
IV. Investigating The Connection between ฮณ-Ray Activity and The Relativistic Jet in 3C 273 during 2015โ2019 89
4.1 Introduction 90
4.2 Observations 91
4.2.1 Fermi-LAT 91
4.2.2 ALMA band3 92
4.2.3 VLBA 43 GHz 92
4.3 Results 94
4.3.1 Light curves 94
4.3.2 Photon indices from weekly and monthly ฮณ-ray light curves 97
4.3.3 Correlation between the radio and ฮณ-ray light curves 99
4.3.4 Parsec-scale jet near the 43 GHz core 102
4.3.5 Polarization 106
4.4 Discussion 108
4.4.1 Positional variations of the stationary components 108
4.4.2 2016 ฮณ-ray outburst 109
4.4.3 2017 ฮณ-ray outburst 112
4.4.4 ฮณ-ray spectra 114
4.5 Summary 115
V. Radio and ฮณ-Ray Activity in The Jet of The Blazar S5 0716+714 117
5.1 Introduction 118
5.2 Observations 120
5.2.1 cm-wavelength data 120
5.2.2 SMA 230 GHz (1.3 mm) 120
5.2.3 ฮณ-ray flux 120
5.3 Results 121
5.3.1 Radio and ฮณ-ray light curves 121
5.3.2 Correlation analysis 121
5.3.2.1 Long-term correlation with the 37 GHz data 121
5.3.2.2 Optimization of the probable time ranges 125
5.3.2.3 DCF curves over the T1, T2, and T3 periods 136
5.3.3 Jet kinematics 140
5.4 Discussion 149
5.4.1 Internal shock interactions 149
5.4.2 Frequency dependence in the time lags 151
5.4.3 Timing of the knot ejections in T1 and T2 153
5.4.4 Location of the ฮณ-ray production site 154
5.4.5 Evolution of the parsec scale jet 155
5.5 Summary 157
VI. Conclusion 161
Bibliography 167
Appendix 183
A Appendices for Chapter4 183
A.1 Gaussian model-fit parameters 183
์์ฝ 189
๊ฐ์ฌ์ ๊ธ 193๋ฐ
๊ธ์ ์ ์ฌ๊ฑด์ ๋ํ ์ถ์์ -๊ตฌ์ฒด์ ๋ฐ์ถ๋ฅผ ์ค์ฌ์ผ๋ก
๋ณธ ์ฐ๊ตฌ๋ ์ถ์์ ๋ฐ์ถ ์ง๋จ๊ณผ ๊ตฌ์ฒด์ ๋ฐ์ถ ์ง๋จ์์ ์ฌ๋ฆฌ์ ์ฐ๋น์ ์ค์ํ ์งํ์ธ ๊ธ์ ์ ์ธ ๋ฏธ๋ ์์ธก์ด ์ด๋ค ์ฐจ์ด๋ฅผ ๋ณด์ด๋์ง๋ฅผ ๊ฒ์ฆํ๊ธฐ ์ํ ๋ชฉ์ ์ผ๋ก ์ํ๋์๋ค. ์ด๋ฅผ ์ํด ๋ง 18์ธ ์ด์ ์ฑ์ธ 268๋ช
์ ๋์์ผ๋ก ์จ๋ผ์ธ ์ค๋ฌธ์กฐ์ฌ๋ฅผ ์ค์ํ๊ณ ์คํฌ๋ฆฌ๋ ๊ณผ์ ์ ๊ฑฐ์ณ ์ฐ์ธํ์ง ์์ ์ํ๋ก ํ๋ณ๋ 83๋ช
์ ๋์์ผ๋ก ZOOMํ๋ก๊ทธ๋จ์ ์ด์ฉํด ๋น๋๋ฉด ์คํ์ ์งํํ์๋ค.
์จ๋ผ์ธ ์ฌ์ ์ธก์ ์ ๋ง์น ์ฐธ์ฌ์๋ ์ถ์์ ๋ฐ์ถ ์ง๋จ๊ณผ ๊ตฌ์ฒด์ ๋ฐ์ถ ์ง๋จ์ ๋ฌด์ ๋ฐฐ์ ๋ ํ ์ฐ๊ตฌ์์ ์ผ๋์ผ๋ก ๋ฐ์ถ ์กฐ์ ๋ฉด๋ด์ ์ค์ํ์๋ค. ์กฐ์ ๋ฉด๋ด์ด ์๋ฃ๋ ํ ์ฌํ ๋ฐ์ถ ๊ฒ์ฌ๋ฅผ ์ค์ํด ๋ฐ์ถ์ ์กฐ์์ด ์ ์ํ๊ฒ ์ผ์ด๋ฌ๋์ง ํ์ธํ์๋ค. ๋ฐ์ถ๊ฒ์ฌ ์๋ฃ ํ ์ฐธ๊ฐ์๋ ๊ธ์ ์ ๋ฏธ๋ ์์ธก ์์ค์ ํ์ ํ์๋ค.
๋ถ์ฑ์คํ ์๋ต์ ํ 6๋ช
์ ์ ์ธํ 77๋ช
์ ์๋ฃ๊ฐ ์ต์ข
๋ถ์์ ์ฌ์ฉ๋์์ผ๋ฉฐ ์ง๋จ ๊ฐ ๋์ง ์ฑ ๊ฒ์ฌ๋ฅผ ์ํด ๋
๋ฆฝํ๋ณธ t-๊ฒ์ ์ ์ค์ํ์๊ณ ๊ธ์ ๋ฐ์ถ ์ฑํฅ์ด ๊ธ์ ์ ๋ฏธ๋ ์์ธก์ ๋ฏธ์น๋ ์ํฅ์ ํ์ธํ๊ธฐ ์ํ์ฌ ์ฑ๋ณ, ์ง๋จ, ๊ธ์ ์ ์ ๋ณํ๋, ๊ธ์ ๋ฐ์ถ๋ฅผ ๋ณ์ธ์ผ๋ก ํ๋ ๋ค์คํ๊ท๋ถ์์ ์ค์ํ์๋ค. ๋ํ ๊ธ์ ์ ๋ฏธ๋ ์์ธก์ด ์ง๋จ ๊ฐ ์ด๋ค ์ฐจ์ด๋ฅผ ๋ณด์ด๋์ง ํ์ธํ๊ธฐ ์ํด ๋
๋ฆฝํ๋ณธ t-๊ฒ์ ์ ์ค์ํ์๋ค.
๋จผ์ ๊ธ์ ๋ฐ์ถ๊ฐ ๊ธ์ ์ ๋ฏธ๋ ์์ธก์ ๋ฏธ์น๋ ์ํฅ์ ๋ค์คํ๊ท๋ถ์์ผ๋ก ๋ถ์ํ ๊ฒฐ๊ณผ, ๊ธ์ ๋ฐ์ถ๊ฐ ๊ธ์ ์ ๋ฏธ๋ ์์ธก์ ์ํฅ์ ๋ฏธ์น๋ ์ ์ผํ ๋ณ์ธ์์ด ๊ฒ์ฆ๋์๋ค. ์ด๋ฅผ ํตํด ์ฐ์ธํ์ง ์์ ์ผ๋ฐ์ธ๋ค์ ๊ธ์ ์ ์ธ ์๊ธฐ ์์ง ํน์ ๊ธ์ ์ ์ ๊ฒฝํ์ ๋ํด ๋ฐ๋ณต์ ์ผ๋ก ์ฌ๊ณ ํ๋ ๊ฒฝํฅ์ด ๋์์๋ก ๊ธ์ ์ ์ธ ๋ฏธ๋๊ฐ ์ฌ ๊ฐ๋ฅ์ฑ์ ๋๊ฒ ํ๊ฐํ๋ค๋ ๊ฒ์ ํ์ธํ ์ ์์๋ค. ๋ํ ์ถ์์ ๋ฐ์ถ ์ง๋จ๊ณผ ๊ตฌ์ฒด์ ๋ฐ์ถ ์ง๋จ์ ๊ธ์ ์ ๋ฏธ๋ ์์ธก์ ๋น๊ตํ ๊ฒฐ๊ณผ ์ถ์์ ๋ฐ์ถ ์ง๋จ์์ ๊ธ์ ์ ๋ฏธ๋ ์์ธก ์์ค์ด ์ ์๋ฏธํ๊ฒ ๋์ ๊ฒ์ด ๋ฐํ์ก๋ค. ๋ ์ง๋จ์ด ์๋ก ๋
๋ฆฝ์ ์ด๊ณ ๋์ง์ ์ผ๋ก ๊ตฌ์ฑ๋์ด์๋ค๋ ๊ฒ ๋ํ ํ์ธ๋์ด ๋ค๋ฅธ ์์ธ๋ค์ด ์๋ ์ง๋จ ๊ฐ ๋ฐ์ถ๋ฐฉ์์ ์ฐจ์ด๊ฐ ๊ธ์ ์ ๋ฏธ๋ ์์ธก์ ์ ์๋ฏธํ ์ฐจ์ด๋ฅผ ๋ง๋ค์ด๋๋ค๋ ๊ฒ์ด ํ์ธ๋์๋ค.
๋ณธ ์ฐ๊ตฌ๋ ์ง๊ธ๊น์ง ํฌ๊ฒ ๊ด์ฌ์ ๋ฐ์ง ๋ชปํ๋ ๊ธ์ ์ ์ ๋ฐ์์์, ํนํ ๊ธ์ ๋ฐ์ถ์ ๊ฐ์ธ์ฐจ์ ๊ธ์ ์ ์ธ ๋ฏธ๋ ์์ธก์ ์คํ์ ์ผ๋ก ์ฐ๊ตฌํ๋ค๋ ์์๊ฐ ์๋ค. ๋ํ ๋ฐ์ถ์ ์ฒ๋ฆฌ๋ฐฉ์์ด๋ก ์ ๋ถ์ ์ ์ํฉ์ ๋ํ ๋ฐ์ถ๊ฐ ์๋, ๊ธ์ ์ ๋ฐ์ถ์์ ํ์ธํ๋ค๋ ํ์ ์ ์์๊ฐ ์์ผ๋ฉฐ ์ค์ ์๋ด ์ฅ๋ฉด์์ ๊ธ์ ์ ์ ๊ฒฝํ์ ํ์ฉํด ๋ด๋ด์์ ์ฌ๋ฆฌ์ ์ฐ๋น์ ๋๋ชจํ ์ ์๋ ๋ฐฉ๋ฒ์ ์ ์ํ๋ค๋ ์๋ด ์ค์ ์ ์์๊ฐ ์๋ค.
์ฃผ์์ด: ๊ธ์ ์ ๋ฏธ๋ ์์ธก, ๊ธ์ ๋ฐ์ถ, ๋ฐ์ถ๋ฐฉ์, ์ถ์์ ๋ฐ์ถ, ๊ตฌ์ฒด์ ๋ฐ์ถThis study was conducted with the aim of verifying the difference in positive future prediction, an important indicator of psychological well-being, in abstract and concrete rumination groups. An online survey was conducted on 268 adults aged 18 and older, and a non-face-to-face experiment was conducted on 83 people who were determined not depressed through the screening process.
After completing online pre-measurements, participants were assigned to either the abstract rumination group or the concrete rumination group, which the researcher then conducted a one-on-one rumination manipulation interview. After the manipulation interview was completed, a posterior rumination test was conducted to verify that the significance of the rumination manipulation. After the completion of the rumination test, participants rated the level of positive future prediction.
Data from 77 people, excluding six who responded insincerely, were used for the final analysis. Independent sample t-tests were conducted for homogeneity tests between groups, and multiple regression analyses were conducted with gender, group, positive affect, and positive rumination. An independent sample t-test was also conducted to determine how positive future predictions differ between groups.
First of all, a multi-regression analysis of the impact of positive reflection on positive future prediction confirmed that positive reflection is the only variable that affects positive future prediction. This confirmed that the higher the tendency of ordinary people to think repeatedly about positive self-qualities or positive emotional experiences, the higher the possibility of predicting a positive future. Furthermore, a comparison of the positive future predictions of the abstract rumination group and the concrete rumination group revealed significantly higher levels of positive future prediction in the abstract rumination group. It has also been confirmed that the two groups are independent and homogeneous from each other, indicating that difference in rumination methods between groups, rather than other factors, have created a significant difference in positive future predictions.
The results of this study is significant in that it sheds light on the difference between positive rumination and positive future prediction, twon important factors which have not received much attention so far. There is also an academic significance in that the processing-mode theory of rumination was identified in positive rumination, not in reflection on negative situation. This study also presented a method of promoting the psychological well-being of clients by utilizing positive affect experience in actual counseling scenes.
Keywords: Positive Future Prediction, Positive Rumination, Processing Mode Theory, Abstract Rumination, Concrete RuminationI. ์ ๋ก 1
1. ์ฐ๊ตฌ์ ํ์์ฑ ๋ฐ ๋ชฉ์ 1
2. ์ฐ๊ตฌ ๋ฌธ์ ๋ฐ ์ฐ๊ตฌ ๊ฐ์ค 6
II. ์ด๋ก ์ ๋ฐฐ๊ฒฝ 8
1. ๊ธ์ ์ ๋ฏธ๋ ๊ธฐ๋์ ์ฌ๋ฆฌ์ ์ฐ๋น 8
2. ๋ฐ์ถ 10
1) ๋ฐ์ถ์ ์ ์ 10
2) ์ ์์ ๋ฐ์ถ์ ๋ถ์ ์์ ๋ฐ์ถ 11
3. ๋ฐ์ถ์ ๋ฏธ๋์์ธก 14
1) ๋ถ์ ์ ์ํฉ์ ๋ํ ๋ฐ์ถ์ ๋ฏธ๋์์ธก 14
2) ๊ธ์ ์ ์ํฉ์ ๋ํ ๋ฐ์ถ์ ๋ฏธ๋์์ธก 15
III. ์ฐ๊ตฌ๋ฐฉ๋ฒ 21
1. ์ฐ๊ตฌ ๋์ 21
2. ์ฐ๊ตฌ ๋๊ตฌ 22
3. ์คํ ์ ์ฐจ 27
4. ๋ถ์ ๋ฐฉ๋ฒ 29
IV. ์ฐ๊ตฌ๊ฒฐ๊ณผ 30
1. ๊ฒฐ๊ณผ๋ถ์์ ์ํ ์๋ฃ๊ฒํ 30
2. ๊ธ์ ์ ๋ฏธ๋์์ธก์ ๊ธ์ ๋ฐ์ถ๊ฐ ๋ฏธ์น๋ ์ํฅ 32
3. ๋ฐ์ถ๋ฐฉ์์ ๋ฐ๋ฅธ ๊ธ์ ์ ๋ฏธ๋์์ธก ์ฐจ์ด 33
โ
ค. ๋
ผ ์ 35
1. ์์ฝ ๋ฐ ๋
ผ์ 35
2. ์ฐ๊ตฌ์ ์์ ๋ฐ ์์ฌ์ 38
3. ์ฐ๊ตฌ์ ์ ํ์ ๋ฐ ํ์์ฐ๊ตฌ ์ ์ธ 40
์ฐธ๊ณ ๋ฌธํ 42
๋ถ๋ก 51
Abastract 76์
A Primary Study on the Development of Evaluation Model for Marine Traffic Safety Assessment
Collision between Xing Guang No.7 and Neo Blue which happened in front of the Incheon lock gate indicates that Korean coastal water is classified as dangerous area due to heavy traffic in confined waters. This may lead to severe accident such as collision, grounding, sinking and environmental pollution.
According to the Marine Traffic Safety Law, revised in 2009, Marine Traffic Safety Diagnosis System is introduced to secure the safe navigation, prevent the marine accident and to maximize the efficiency of the port. The diagnosis system aims to investigate, measure and evaluate the effect of the various development project such as the construction of bridge and/or piers, etc. and to reflect the diagnostic results for the safe navigation.
In the process of this system, the most important part is the marine traffic safety assessment, and evaluation model is required in order to implement the assessment.
However, the evaluation model used in Korea is highly limited, and these models are made in foreign countries such as Japan. There are some problems to apply these models to Korean coastal waters. So the development of the proper evaluation model for Korea is required as early as possible.
The purpose of this research is implementing marine traffic assessment of Korean coastal waters by using ES(Environmental Stress) model which is formal assessment model for marine traffic flow simulation in the Diagnosis System and IWRAP(IALA Waterway Risk Assessment Program) recommended by IALA, and analyze the results for the basic reference to develop independent evaluation model.์ 1 ์ฅ ์ ๋ก 1
1.1 ์ฐ๊ตฌ์ ๋ฐฐ๊ฒฝ ๋ฐ ๋ชฉ์ 1
1.2 ์ฐ๊ตฌ์ ๋ฐฉ๋ฒ 2
์ 2 ์ฅ ํด์๊ตํต ์์ ์ง๋จ์ ๋์ ๊ฐ๋
๊ณผ ์ ์ฐจ 4
2.1 ํด์๊ตํต ์์ ์ง๋จ์ ์ฉ์ด ์ ์ 4
2.1.1 ํด์๊ตํต์ ๊ฐ๋
4
2.1.2 ์์ ์ ๊ฐ๋
4
2.1.3 ์ง๋จ์ ๊ฐ๋
5
2.2 ํด์๊ตํต ์์ ์ง๋จ์ ๋ 6
2.2.1 ํด์๊ตํต ์์ ์ง๋จ์ ๊ฐ๋
6
2.2.2 ํด์๊ตํต ์์ ์ง๋จ ์ ์ฐจ 9
์ 3 ์ฅ ํด์๊ตํต ์์ ์ฑ ํ๊ฐ ์ ์ฐจ ๋ฐ ํ๊ฐ๋ชจ๋ธ ์กฐ์ฌ 11
3.1 ํด์๊ตํต ์์ ์ฑ ํ๊ฐ์ ๊ฐ๋
11
3.2 ํด์๊ตํต ์์ ์ฑ ํ๊ฐ ์ ์ฐจ 12
3.2.1 ํด์๊ตํตํ์ ํ์
13
3.2.2 ํด์๊ตํตํ์ ๊ธฐ์ 13
3.2.3 ํด์๊ตํตํ์ ์์ธก 14
3.2.4 ํด์๊ตํตํ์ ์ฌํ 14
3.2.5 ํด์๊ตํตํ์ ํ๊ฐ 15
3.3 ํด์๊ตํต ์์ ์ฑ ํ๊ฐ๋ชจ๋ธ 16
3.3.1 IWRAP 16
3.3.2 ES Model 22
3.3.3 PAWSA 26
3.3.4 FSA 30
3.3.5 US Model 35
3.3.6 ์ผ๋ณธ์ ์์ ๋์ฑ
ํ๊ฐ ๊ฐ์ด๋๋ผ์ธ 36
3.3.7 ๊ธฐํ ํ๊ฐ๋ชจ๋ธ 39
3.3.8 ์ข
ํฉ ๋ถ์ 40
์ 4 ์ฅ IWRAP ๋ฐ ES Model์ ํ์ฉํ ์ธ์ฐํญ ํด์ญ ํด์๊ตํต ์์ ์ฑ ํ๊ฐ 42
4.1 ๊ธฐ์ด ์๋ฃ ์กฐ์ฌ 42
4.1.1 ์์ฐ ํ๊ฒฝ 42
4.1.2 ํญํ ํ๊ฒฝ 44
4.2 IWRAP์ ์ด์ฉํ ์ธ์ฐํญ ํด์๊ตํต ์์ ์ฑ ํ๊ฐ 46
4.2.1 Leg ์ง์ 46
4.2.2 ๊ตํต๋ ๋ฐ ๋ถ์ฐ์น ์
๋ ฅ 48
4.2.3 ๊ธฐํ ๋ณ์ ์
๋ ฅ 57
4.2.4 ์์ ์ฑ ํ๊ฐ ๊ฒฐ๊ณผ ๋ถ์ 58
4.3 ES Model์ ์ด์ฉํ ์ธ์ฐํญ ํด์๊ตํต ์์ ์ฑ ํ๊ฐ 60
4.4 ํด์์ฌ๊ณ ํต๊ณ์๋ฃ ๋น๊ต ๋ถ์ 62
์ 5 ์ฅ ๊ฒฐ ๋ก 6
Detection of Intestinal Protozoa in Korean Patients Using BD MAX Enteric Parasite Panel and Seegene Allplex Gastrointestinal Parasite Assay
Background: Intestinal protozoan infection is one of the main causes of gastrointestinal diseases. Protozoa are usually detected by direct
smear microscopy, concentration techniques, or special stains; however, these techniques are labor-intensive and require well-trained technicians.
Therefore, molecular techniques involving polymerase chain reaction (PCR) have been developed to satisfy the need for unbiased and rapid ana lytical methods with high sensitivity and specificity. In this study, the BD MAXTM Enteric Parasite Panel (EPP) (Becton, Dickinson and Company, USA),
designed to detect Cryptosporidium parvum and/or hominis, Giardia lamblia, and Entamoeba histolytica, and the AllplexTM Gastrointestinal Para site Assays (AGPA) (Seegene Inc., Korea), designed to detect Cryptosporidium species, G. lamblia, E. histolytica, Blastocystis hominis, Dientamoe ba fragilis, and Cyclospora cayetanensis were compared to determine whether any of these assays could become a useful tool for detecting intes tinal protozoan infections in Korea.
Methods: We investigated 295 fecal samples using EPP and AGPA. Then we confirmed the positive results with the conventional and nested PCR.
Consistent detection by conventional PCR, nested PCR, and one of the multiplex panels was considered โtrue positive.โ
Results: Out of 295 samples, 17 were true positives for B. hominis and 2 were true positives for E. histolytica. EPP detected parasites in only two
samples owing to its design; however, its true positive detection rate was 100% (2/2). AGPA detected parasites in 24 samples with 79.2% (19/24)
true positives.
Conclusions: The incidence of protozoan, especially B. hominis, infection may be more prevalent than expected. AGPA could be an effective tool
for screening protozoan infections.ope
A Case Report of Transfusion-associated Circulatory Overload
Transfusion-associated circulatory overload (TACO) is recently becoming more important than transfusion-related acute lung injury (TRALI) in terms of the number of patients with definite diagnosis as well as its prognosis. In order to diagnose TACO, it is helpful to recognize early the symptoms suspicious of transfusion reaction through electronic medical record system and computer network, and this will be of help for obtaining samples for brain natriuretic peptide (BNP) measurement before and after the onset of transfusion reaction. We report a case in which a transfusion reaction was diagnosed as TACO. A 62-year-old woman was admitted to the emergency room due to bleeding tendency. Two fresh frozen plasma units and one unit of leukocyte-reduced red blood cells were transfused. Blood pressure increased during transfusion, and the chest X-ray showed findings suggestive of newly developed pulmonary edema. N-terminal prohormone of BNP (NT-proBNP) test was carried out using the specimens in refrigerated storage. Compared with the NT-proBNP level measured 12 hours before the transfusion, that measured 6 hours after the transfusion was markedly increased (>48 fold of pre-transfusion level). As a result, this case was diagnosed with TACO.ope
Determination of Colistin Resistance by Simple Disk Diffusion Test Using Modified Mueller-Hinton Agar
Background: Colistin has become a last-resort antibiotic for the management of multidrug-resistant gram-negative bacteria. The disk diffusion test is cheap and easy to perform but may be unreliable for colistin susceptibility testing due to poor diffusion of the large colistin molecule. An improved agar diffusion test would increase the reliability of colistin susceptibility testing. This study aimed to modify Muller-Hinton agar (MHA) to improve colistin diffusion in agar.
Methods: MHA was modified by reducing the agar concentration from 100% to 30% and supplementing with protamine. We tested 60 gram-negative clinical isolates of Pseudomonas aeruginosa (N=27) and Acinetobacter calcoaceticus-baumannii complex (N=33). Disk diffusion test results were interpreted based on minimum inhibitory concentrations determined by broth microdilution.
Results: The modified MHA yielded the best performance metrics, including 94.7% sensitivity, 100% specificity, and an area under the curve of 0.995 (95% confidence interval, 0.982-1.000), P<0.001, at a cut-off point of 13 mm.
Conclusions: A reduction of the agar concentration from 100% to 30% and the addition of protamine improved colistin diffusion in agar and allowed routine colistin susceptibility testing in a clinical microbiology laboratory, but should be handled with caution.ope
Evaluation of the Analytical Performance of Atellica CH 930 Automated Chemistry Analyzer
Background: Recently, a new automated chemistry analyzer, Atellica CH930 (Siemens, Germany), was introduced. It automatically measures internal quality control (QC) materials according to a pre-determined schedule. For this purpose, the instrument has space for storage of QC materials. We evaluated the analytical performance of chemistry items by using the Atellica system.
Methods: The precision of 29 items was evaluated with three levels of QC materials with two storage methods. We stored the QC materials in the dedicated storage space in the instrument during the precision evaluation period. In addition, we aliquoted and stored the materials in the refrigerator, and then loaded the material in a timely manner. Linearity, carry-over, and agreement with current methods were also evaluated.
Results: The within-laboratory coefficient of variation (CV) of most items, except for total CO2 (tCO2), was within 5.0% in both QC storage methods without significant differences in CV between storage methods. The CV of tCO2 was 5.2%, 5.8%, and 5.1% at three different levels when the QC materials were stored in a dedicated space in the instrument. The linearity was acceptable, showing <5% nonlinearity. Although good agreement was observed for most items, some items, such as calcium, total bilirubin, aspartate transaminase, and chloride, showed unequivalent results.
Conclusions: Atellica CH930 showed acceptable precision, linearity, and agreement in routine chemistry items. The automatic QC function using the storage device has no problem with stability or precision. It can reduce the manual process, allowing technicians to focus on reviewing the QC results and reporting reliable results.ope
A Case of Panagglutination on Antibody Identification in a Multiple Myeloma Patient Receiving Daratumumab
Herein, we report a patient showing panagglutination in the unexpected antibody identification test after the administration of daratumumab. The patient was a 66-year-old woman who had undergone multiple cycles of chemotherapy and autologous peripheral blood stem cell transplantation for treating multiple myeloma; however, despite treatment, she had relapsed. Therefore, daratumumab, on clinical trials in Korea, started to be administered. After administration of daratumumab, the result of antibody screening test was positive, on the contrary to the result prior to the administration. Moreover, all positive reactions were shown in the antibody identification to the panel cells. After destroying CD38 antigens on the surface of RBCs using DTT, negative results were obtained. Daratumumab?a novel therapeutic human CD38 monoclonal antibody that can be used as targeted immunotherapy?is an FDA-approved drug for treating multiple myeloma. Because CD38 is expressed not only on myeloma cells, but also on red blood cells (RBCs), the use of daratumumab might lead to RBC agglutinations, and thereby resulting in false-positive results on the pre-transfusion tests. Therefore, caution is needed in case of a patient receiving daratumumab. Furthermore, additional test using DTT is required, especially when panagglutination was shown in the antibody identification test, as in this case.ope
A Structural Model of the Relationship between Perceptions of Organizational Politics and Organizational Commitment with Organizational Cynicism as a Mediator: Exploring the Negative Factors Affecting the Organizational Commitment of Local Government Employees
์กฐ์ง๋ชฐ์
์ ์กฐ์ง์ ๊ฒฝ์์ฐ์๋ฅผ ํ๋ณดํ๊ธฐ ์ํ ์ค์ ์๋จ์ผ๋ก ์ธ์๋๋ฉด์ ์ด์ ๋ค์ํ ์ํฅ๋ณ์ธ๋ค์ ๋ํ ์ฐ๊ตฌ๊ฐ ์ด๋ฃจ์ด์ ธ ์์ง๋ง ๋ถ์ ์ ์ํฅ์์ธ์ ๋ํ ์ฐ๊ตฌ๋ ์์์ ๋ถ๊ณผํ๋ค. ๋ณธ ์ฐ๊ตฌ๋ ์กฐ์ง์ ์น์ง๊ฐ ๋ฐ ์กฐ์ง๋์์ฃผ์๊ฐ ์กฐ์ง๋ชฐ์
์ ๋ถ์ ์ ์ํฅ๋ณ์๋ก ๊ธฐ๋ฅํ ๊ฒ์ผ๋ก ๊ฐ์ ํ์ฌ, ์ด ๋ค ์ํฅ ๋ฐ ๊ฒฐ๊ณผ ๋ณ์ธ๋ค๊ฐ์ ๊ตฌ์กฐ์ ๊ด๊ณ๋ฅผ ์ค์ฆ์ ์ผ๋ก ๋ถ์ํ๋ ๋ฐ ๋ชฉ์ ์ ๋๋ค. ์ด๋ฅผ ์ํด ๊ฒฝ๋จ์ง์ญ ๊ด๋ฃ 221๋ช
์ ๋ถ์ ๋์์ผ๋ก ํ์๋ค. ๋ถ์ ๊ฒฐ๊ณผ, ์กฐ์ง์ ์น์ง๊ฐ๊ณผ ์กฐ์ง๋์์ฃผ์๋ ์กฐ์ง๋ชฐ์
(๊ฐ์น ๋ฐ ๊ทผ์๋ชฐ์
)์ ๋ถ์ ์ ์ํฅ๋ณ์ธ์ผ๋ก ๊ธฐ๋ฅํ๋ค๋ ๊ฒ์ด ํ์ธ๋์์ผ๋ฉฐ, ํนํ, ์กฐ์ง๋์์ฃผ์๋ ์ํฅ๋ณ์ธ๊ณผ ๊ฒฐ๊ณผ๋ณ์ธ์ ๋ถ๋ถ ๋งค๊ฐํ๋ ๊ธฐ๋ฅ๋ ์กด์ฌํ๋ ๊ฒ์ผ๋ก ๋ํ๋ฌ๋ค. ๋ฐ๋ผ์ ๋ณธ ์ฐ๊ตฌ๋ ํ์ ์๋น์ค์ ์ง์ ์ ๊ณ ๋ฅผ ์ํด์๋ ๊ด๋ฃ๋ค์ ์๋ฐ์ ์ด๊ณ ํ์ ์ ์ธ ๋
ธ๋ ฅ์ ๋ถ์ ์ ์ผ๋ก ์์ฉํ๋ ์กฐ์ง์ ์น์ง๊ฐ๊ณผ ์กฐ์ง๋์์ฃผ์์ ๊ฐ์ ์์ธ๋ค์ ๋ฐฐ์ ํ ์ ์๋ ์กฐ์ง ๋ถ์๊ธฐ ํ์ฑ์ด ์ ์ ๋์ด์ผ ํ๋ค๋ ๊ฒ์ ๊ฒฝํ์ ์ผ๋ก ์
์ฆํ์๋ค๋ ์ ์์ ์๋ฏธ๋ฅผ ๊ฐ์ง๋ค
- โฆ