1,556 research outputs found
High-energy electromagnetic, neutrino, and cosmic-ray emission by stellar-mass black holes in disks of active galactic nuclei
Some Seyfert galaxies are detected in high-energy gamma rays, but the
mechanism and site of gamma-ray emission are unknown. Also, the origins of the
cosmic high-energy neutrino and MeV gamma-ray backgrounds have been veiled in
mystery since their discoveries. We propose emission from stellar-mass BHs
(sBHs) embedded in disks of active galactic nuclei (AGN) as their possible
sources. These sBHs are predicted to launch jets due to the Blandford-Znajek
mechanism, which can produce intense electromagnetic, neutrino, and cosmic-ray
emissions. We investigate whether these emissions can be the sources of cosmic
high-energy particles. We find that emission from internal shocks in the jets
can explain gamma rays from nearby radio-quiet Seyfert galaxies including
NGC1068, if the Lorentz factor of the jets () is high. On the
other hand, for moderate , the emission can significantly
contribute to the background gamma-ray and neutrino intensities in the and bands, respectively. Furthermore, for
moderate with efficient amplification of the magnetic field
and cosmic-ray acceleration, the neutrino emission from NGC1068 and the
ultrahigh-energy cosmic rays can be explained. These results suggest that the
neutrino flux from NGC1068 as well as the background intensities of
gamma rays, neutrinos, and the ultrahigh-energy cosmic rays can be explained by
a unified model. Future MeV gamma-ray satellites will test our scenario for
neutrino emission.Comment: 14 pages, 8 figures, accepted in Ap
Shock cooling and breakout emission for optical flares associated with gravitational wave events
The astrophysical origin of stellar-mass black hole (BH) mergers discovered
through gravitational waves (GWs) is widely debated. Mergers in the disks of
active galactic nuclei (AGN) represent promising environments for at least a
fraction of these events, with possible observational clues in the GW data. An
additional clue to unveil AGN merger environments is provided by possible
electromagnetic emission from post-merger accreting BHs. Associated with BH
mergers in AGN disks, emission from shocks emerging around jets launched by
accreting merger remnants is expected. In this paper we compute the properties
of the emission produced during breakout and the subsequent adiabatic expansion
phase of the shocks, and we then apply this model to optical flares suggested
to be possibly associated with GW events. We find that the majority of the
reported flares can be explained by the breakout and the shock cooling
emission. If these events are real, then the merging locations of binaries are
constrained depending on the emission processes. If the optical flares are
produced by shock cooling emission, they would display moderate color
evolution, possibly color variations among different events, a positive
correlation between the delay time and the duration of flares, and accompanying
breakout emission in X-ray bands before the optical flares. If the breakout
emission dominates the observed lightcurve, it is expected that the color is
distributed in a narrow range in the optical band, and the delay time from GW
to electromagnetic emission is longer than days. Hence, further
explorations of the distributions of delay times, color evolution of the
flares, and associated X-ray emission will be useful to test the proposed
emission model for the observed flares.Comment: 15 pages, 3 figure
Observable signatures of stellar-mass black holes in active galactic nuclei
Stellar-mass black holes (BHs) are predicted to be embedded in the disks of
active galactic nuclei (AGN) due to gravitational drag and in-situ star
formation. However, clear evidence for AGN disk-embedded BHs is currently
lacking. Here, as possible electromagnetic signatures of these BHs, we
investigate breakout emission from shocks emerging around Blandford-Znajek jets
launched from accreting BHs in AGN disks. We assume that the majority of the
highly super-Eddington flow reaches the BH, produces a strong jet, and the jet
produces feedback that shuts off accretion and thus leads to episodic flaring.
While these assumptions are highly uncertain at present, they predict a
breakout emission characterized by luminous thermal emission in the X-ray
bands, and bright, broadband non-thermal emission from the infrared to the
gamma-ray bands. The flare duration depends on the BH's distance from the
central supermassive BH, varying between s for pc.
This emission can be discovered by current and future infrared, optical, and
X-ray wide-field surveys and monitoring campaigns of nearby AGNs.Comment: 10 pages, 4 figures, accepted in ApJ
Diagnosis of infections in newborns using a new particle-mediated immunoassay for serum C-reactive protein
C-reactive protein (CRP) levels were measured using a new particle-mediated immunoassay. Tests for precision and linearity of this method gave satisfactory results. The minimum sensitivity of the assay was 1 ng/ml. Interference by bilirubin (<220mg/l) and haemoglobin (<20g/l) was not observed. Using this method,
CRP was assayed as a means of monitoring for infection in newborns up to 72 h after delivery. The pattern of time course elevation curves was similar for both groups (10 healthy subjects and 26 patients), but the serum CRP (ng/ml) of infected newborns rose significantly higher than in healthy subjects at 24 h after birth. The rate of increase of CRP (∆CRP; ng/ml/h) may be a more useful parameter to detect infection, since a significant change in ∆CRP was apparent only 12 h after birth. The reported method was reliable and the parameters obtained were considered clinically useful for early detection of infection
Cosmic Evolution of Stellar-mass Black Hole Merger Rate in Active Galactic Nuclei
Binary black hole mergers encode information about their environment and the
astrophysical processes that led to their formation. Measuring the redshift
dependence of their merger rate will help probe the formation and evolution of
galaxies and the evolution of the star formation rate. Here we compute the
cosmic evolution of the merger rate for stellar-mass binaries in the disks of
Active Galactic Nuclei (AGNs). We focus on recent evolution out to redshift
, covering the accessible range of current Earth-based gravitational-wave
observatories. On this scale, the AGN population density is the main
contributor to redshift-dependence. We find that the AGN-assisted merger rate
does not meaningfully evolve with redshift, differentiating this channel from
field binaries and some other dynamical formation scenarios.Comment: 6 pages, 2 figure
Enzootic bovine leukosis accompanied by splenomegaly in an 8-month-old calf
ΔΕΝ ΔΙΑΤΙΘΕΤΑΙ ΠΕΡΙΛΗΨΗIn this report, an 8-month-old calf (crossbred, Holstein × Japanese Black) developed fever and accompanied abomasum displacement. Blood chemical test showed remarkably high values of white blood cell count and heteromorphic lymphocytes. In pathological appraisal, enlarged splenomegaly and swelling of the lymph nodes were observed. Histopathological examination revealed invasion of tumor cells derived from B1 cells into systemic lymph nodes, liver and spleen. The provirus loads of bovine leukemia virus (BLV) was 1,439 copies per 10 ng DNA by using real time PCR. In conclusion, this case was diagnosed as bovine leukemia caused by BLV infection with a huge splenomegaly
WWP1 knockout in mice exacerbates obesity-related phenotypes in white adipose tissue but improves whole-body glucose metabolism
Synthetic DNA immunotherapy in biochemically relapsed prostate cancer
Background: INO-5150 (PSA and PSMA) +/- INO-9012 (IL-12), a synthetic DNA immunotherapy, was assessed for safety, immunogenicity and efficacy in biochemically recurrent prostate cancer patients (pts).
Methods: Phase I, open-label, multi-center study in the US included pts with rising PSA after surgery and/or RT, PSA doubling time (PSADT) \u3e3 months (mos), testosterone \u3e150 ng/dL and no concurrent ADT. Safety, immunogenicity and efficacy (PSA kinetics, PFS) were evaluated in 4 treatment arms of 15 pts each. Arms A: 2mg INO-5150, B: 8.5 mg INO-5150, C: 2mg INO-5150 + 1mg INO-9012 and D: 8.5mg INO-5150 + 1mg INO-9012. Pts received 4 IM doses of vaccine followed by electroporation on day 0, wks 3, 12 and 24 and were followed for 72 wks.
Results: 50/61 (82%) pts completed all visits and treatments were well tolerated with no safety concerns. Median PFS for overall population [N = 61, baseline (D0) PSADT range (mos) 1.5-217.1, median 9.8] and for a subset of pts with D0 PSADT ≤12mos (N = 36) has not yet been reached (FU 3-19 mos). 86% of pts with D0 PSADT ≤12 mos were progression free through 19mos FU. 27 out of 36 (75%) pts with D0 PSADT≤ 12 mos had disease stabilization at wks 27 evidenced by significant improvement in log2PSA change over time (slope) and PSADT from D0 (Slope=0.19 declined to 0.1, PSADT=5.3 improved to 10.1 mos, p = \u3c0.0001). This effect was maintained at wk 72 (Slope=0.09, PSADT=10.6, p = \u3c0.0001). Immunogenicity was observed in 77% (47/61) of pts by multiple immunologic assessments. Patient immunogenicity to INO-5150 as determined by CD38 and Perforin + CD8 T cell immune reactivity correlated with attenuated % PSA rise compared to pts without reactivity (p = 0.05, n = 50).
Conclusions: INO-5150 +/- INO-9012 was safe, well tolerated and immunogenic. Clinical efficacy was observed in the patients with D0 PSADT≤ 12 mos as evidenced by a significant dampening of log2PSA change over time and increased PSADT up to 72 weeks FU. Additional genomic analyses are ongoing to further elucidate the correlation of immunologic efficacy and clinical benefit. (NCT02514213)
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