7,840 research outputs found
Interferometric Monitoring of Gamma-ray Bright AGNs: 4C +28.07 and its Synchrotron Self-absorption Spectrum
We present the analysis results of the simultaneous multifrequency
observations of the blazar 4C +28.07. The observations were conducted by the
Interferometric Monitoring of Gamma-ray Bright Active Galactic Nuclei (iMOGABA)
program, which is a key science program of the Korean Very Long Baseline
Interferometry (VLBI) Network (KVN). Observations of the iMOGABA program for 4C
+28.07 were conducted from 16 January 2013 (MJD 56308) to 13 March 2020 (MJD
58921). We also used {\gamma}-ray data from the Fermi Large Array Telescope
(Fermi-LAT) Light Curve Repository. We divided the iMOGABA data and the
Fermi-LAT data into five periods from 0 to 4, according to the prosody of the
22 GHz data and the presence or absence of the data. In order to investigate
the characteristics of each period, the light curves were plotted and compared.
However, a peak was observed earlier than the period of a strong {\gamma}-ray
flare at 43-86 GHz in period 3 (MJD 57400-58100). Therefore, we assumed that
the minimum total CLEANed flux density for each frequency was quiescent flux
(Sq), with the variable flux (Svar) obtained by subtracting Sq from the values
of the total CLEANed flux density. We then compared the variability of the
spectral indices ({\alpha}) between adjacent frequencies. Most notably,
{\alpha}22-43 showed optically thick spectra in the absence of a strong
{\gamma}-ray flare, and when the flare appeared, {\alpha}22-43 became optically
thinner. In order to find out the characteristics of the magnetic field in the
variable region, the magnetic field strength in the synchrotron self-absorption
(BSSA) and the equipartition magnetic field strength (Beq) were obtained. We
found that BSSA is largely consistent with Beq within the uncertainty, implying
that the SSA region in the source is not significantly deviated from the
equipartition condition in the {\gamma}-ray quiescent periods.Comment: 23 pages, accepted by JKA
The Singer's Formant and Speaker's Ring Resonance: A Long-Term Average Spectrum Analysis
ObjectivesWe previously showed that a trained tenor's voice has the conventional singer's formant at the region of 3 kHz and another energy peak at 8-9 kHz. Singers in other operatic voice ranges are assumed to have the same peak in their singing and speaking voice. However, to date, no specific measurement of this has been made.MethodsTenors, baritones, sopranos and mezzo sopranos were chosen to participate in this study of the singer's formant and the speaker's ring resonance. Untrained males (n=15) and females (n=15) were included in the control group. Each subject was asked to produce successive /a/ vowel sounds in their singing and speaking voice. For singing, the low pitch was produced in the chest register and the high notes in the head register. We collected the data on the long-term average spectra of the speaking and singing voices of the trained singers and the control groups.ResultsFor the sounds produced from the head register, a significant energy concentration was seen in both 2.2-3.4 kHz and 7.5-8.4 kHz regions (except for the voices of the mezzo sopranos) in the trained singer group when compared to the control groups. Also, the chest register had a significant energy concentration in the 4 trained singer groups at the 2.2-3.1 kHz and 7.8-8.4 kHz. For speaking sound, all trained singers had a significant energy concentration at 2.2-5.3 kHz and sopranos had another energy concentration at 9-10 kHz.ConclusionThe results of this study suggest that opera singers have more energy concentration in the singer's formant/speaker's ring region, in both singing and speaking voices. Furthermore, another region of energy concentration was identified in opera singer's singing sound and in sopranos' speaking sound at 8-9 kHz. The authors believe that these energy concentrations may contribute to the rich voice of trained singers
In-situ fabrication of cobalt-doped SrFe2As2 thin films by using pulsed laser deposition with excimer laser
The remarkably high superconducting transition temperature and upper critical
field of iron(Fe)-based layered superconductors, despite ferromagnetic material
base, open the prospect for superconducting electronics. However, success in
superconducting electronics has been limited because of difficulties in
fabricating high-quality thin films. We report the growth of high-quality
c-axis-oriented cobalt(Co)-doped SrFe2As2 thin films with bulk
superconductivity by using an in-situ pulsed laser deposition technique with a
248-nm-wavelength KrF excimer laser and an arsenic(As)-rich phase target. The
temperature and field dependences of the magnetization showing strong
diamagnetism and transport critical current density with superior Jc-H
performance are reported. These results provide necessary information for
practical applications of Fe-based superconductors.Comment: 8 pages, 3figures. to be published at Appl. Phys. Let
Tau functions as Widom constants
We define a tau function for a generic Riemann-Hilbert problem posed on a
union of non-intersecting smooth closed curves with jump matrices analytic in
their neighborhood. The tau function depends on parameters of the jumps and is
expressed as the Fredholm determinant of an integral operator with block
integrable kernel constructed in terms of elementary parametrices. Its
logarithmic derivatives with respect to parameters are given by contour
integrals involving these parametrices and the solution of the Riemann-Hilbert
problem. In the case of one circle, the tau function coincides with Widom's
determinant arising in the asymptotics of block Toeplitz matrices. Our
construction gives the Jimbo-Miwa-Ueno tau function for Riemann-Hilbert
problems of isomonodromic origin (Painlev\'e VI, V, III, Garnier system, etc)
and the Sato-Segal-Wilson tau function for integrable hierarchies such as
Gelfand-Dickey and Drinfeld-Sokolov.Comment: 26 pages, 6 figure
Leukoaraiosis is associated with pneumonia after acute ischemic stroke
Diagnostic criteria for stroke associated pneumonia based on the CDC criteria. (DOCX 25 kb
Unleashing the full potential of Hsp90 inhibitors as cancer therapeutics through simultaneous inactivation of Hsp90, Grp94, and TRAP1
Cancer therapeutics: Extending a drug's reach A new drug that blocks heat shock proteins (HSPs), helper proteins that are co-opted by cancer cells to promote tumor growth, shows promise for cancer treatment. Several drugs have targeted HSPs, since cancer cells are known to hijack these helper proteins to shield themselves from destruction by the body. However, the drugs have had limited success. Hye-Kyung Park and Byoung Heon Kang at Ulsan National Institutes of Science and Technology in South Korea and coworkers noticed that the drugs were not absorbed into mitochondria, a key cellular compartment, and HSPs in this compartment were therefore not being blocked. They identified a new HSP inhibitor that can reach every cellular compartment and inhibit all HSPs. Testing in mice showed that this inhibitor effectively triggered death of tumor cells, and therefore shows promise for anti-cancer therapy. The Hsp90 family proteins Hsp90, Grp94, and TRAP1 are present in the cell cytoplasm, endoplasmic reticulum, and mitochondria, respectively; all play important roles in tumorigenesis by regulating protein homeostasis in response to stress. Thus, simultaneous inhibition of all Hsp90 paralogs is a reasonable strategy for cancer therapy. However, since the existing pan-Hsp90 inhibitor does not accumulate in mitochondria, the potential anticancer activity of pan-Hsp90 inhibition has not yet been fully examined in vivo. Analysis of The Cancer Genome Atlas database revealed that all Hsp90 paralogs were upregulated in prostate cancer. Inactivation of all Hsp90 paralogs induced mitochondrial dysfunction, increased cytosolic calcium, and activated calcineurin. Active calcineurin blocked prosurvival heat shock responses upon Hsp90 inhibition by preventing nuclear translocation of HSF1. The purine scaffold derivative DN401 inhibited all Hsp90 paralogs simultaneously and showed stronger anticancer activity than other Hsp90 inhibitors. Pan-Hsp90 inhibition increased cytotoxicity and suppressed mechanisms that protect cancer cells, suggesting that it is a feasible strategy for the development of potent anticancer drugs. The mitochondria-permeable drug DN401 is a newly identified in vivo pan-Hsp90 inhibitor with potent anticancer activity
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