110 research outputs found
Primordial Black Holes in the Cosmological Context and Transient Electromagnetic Signatures from Merging Black Hole Binaries
The cosmological evolution of primordial black holes (PBHs) is presented via analysis of the accretion and evaporation histories of the holes. The ultimate end of any BH is evaporation â a spectacular seconds-long burst of high-energy radiation and particles. The critical initial mass of a PBH undergoing current era evaporation is ⌠510 trillion grams. A near- critical mass PBH will not accrete radiation or matter in sufficient quantity to retard its inevitable evaporation, if the hole remains within an average volume of the universe. The gravitational waves (GWs) from five BH binary merger events discovered by the LIGO/Virgo collaborations were BHs of a few to tens of solar masses merging at redshift z ⌠0.1. It is plausible these systems began as PBHs within overdense regions of the Universe. However, it is difficult for isolated PBHs to become supermassive black holes (SMBHs) at high redshift.
A new type of electromagnetic (EM) counterpart is presented. During the inspiral of a SMBH binary system, copious amounts of GW and EM energy are injected into the surrounding interstellar medium. The injected EM energy produces a relativistic blastwave, which emits synchrotron radiation in a transient multiwavelength afterglow. A simultaneous detection of the GWs and afterglow emission will contribute insights into blastwave dynamics, the BH masses and angular momenta, and the inner galactic environment
Simultaneous amplification and screening of whole plasmids using the T7 bacteriophage replisome
This study describes a novel helicase-mediated isothermal DNA amplification method that exponentially amplifies circular DNAs. The circular helicase-dependent amplification (cHDA) system is based on the T7 replication machinery, which includes the processive T7 helicase, an exonuclease-deficient T7 DNA polymerase (T7 Sequenase) and the T7 Gp2.5 single-stranded DNA-binding (SSB) protein. After the duplex DNA template is unwound by the T7 helicase, specific primers anneal to the separated DNA strands and T7 Sequenase extends the 3âČ end of each primer by a rolling circle mechanism to amplify not only a region defined by the primers but also continuous concatemers of the template. The cHDA reaction can be carried out at one temperature (25°C) for the entire process and can achieve up to 10â000-fold amplification. Amplification can be performed using purified plasmid DNA or a crude cell lysate and can amplify inserts as large as 10 kb. Following a cHDA reaction, the amplified products can be used directly for sequencing and restriction enzyme digestion without further purification. By utilizing the helicase enzyme, circular DNA samples can be simultaneously screened and amplified at one constant temperature in one easy step
Constraining the Charge of a Black Hole with Electromagnetic Radiation from a Black Hole-Neutron Star System
Black hole-neutron star (BH-NS) mergers are expected to emit
gravitational-wave (GW) and electromagnetic (EM) counterparts when the NS is
tidally disrupted or plunges into the BH. Recently, GW 200105 and GW200115 were
claimed as originating in BH-NS mergers, even GW 200105 remains in debate.
Several optical source candidates are reported to possible associate with the
two GW events, but not confirmed yet. In this work, we assume that the BH is
charged (the NS is naturally charged) and try to constrain the charge of the BH
by using the possible associated EM emission from the charged BH and NS system
working in the inspiral regime. We adopt electric and magnetic dipole
radiations for the binaries which power a Poynting-flux-dominated outflow to
accelerate electrons. Then, it produces the observed EM radiation via
synchrotron radiation. We find that the conversion efficiency in the X-ray band
is much higher than that of the ultraviolet (UV), near-infrared, and radio
bands. The estimated maximum charge-to-mass ratio (the charge for unit mass) of
the BH is and esu for the binary
systems of GW200105 and GW200115, respectively, if magnetic field strength
G and period ms for the NS spin.Comment: 13 pages, 4 Tables, and 2 Figures. Accepted for publication in PR
Interaction of the magnetorotational instability with hydrodynamic turbulence in accretion disks
Accretion disks in which angular momentum transport is dominated by the
magnetorotational instability (MRI) can also possess additional, purely
hydrodynamic, drivers of turbulence. Even when the hydrodynamic processes, on
their own, generate negligible levels of transport, they may still affect the
evolution of the disk via their influence on the MRI. Here, we study the
interaction between the MRI and hydrodynamic turbulence using local MRI
simulations that include hydrodynamic forcing. As expected, we find that
hydrodynamic forcing is generally negligible if it yields a saturated kinetic
energy density that is small compared to the value generated by the MRI. For
stronger hydrodynamic forcing levels, we find that hydrodynamic turbulence
modifies transport, with the effect varying depending upon the spatial scale of
hydrodynamic driving. Large scale forcing boosts transport by an amount that is
approximately linear in the forcing strength, and leaves the character of the
MRI (for example the ratio between Maxwell and Reynolds stresses) unchanged, up
to the point at which the forced turbulence is an order of magnitude stronger
than that generated by the MRI. Low amplitude small scale forcing may modestly
suppress the MRI. We conclude that the impact of hydrodynamic turbulence on the
MRI is generically ignorable in cases, such as convection, where the additional
turbulence arises due to the accretion energy liberated by the MRI itself.
Hydrodynamic turbulence may affect (and either enhance or suppress) the MRI if
it is both strong, and driven by independent mechanisms such as self-gravity,
supernovae, or solid-gas interactions in multiphase protoplanetary disks.Comment: ApJ, in pres
Photocathode Behavior During High Current Running in the Cornell ERL Photoinjector
The Cornell University Energy Recovery Linac (ERL) photoinjector has recently
demonstrated operation at 20 mA for approximately 8 hours, utilizing a
multialkali photocathode deposited on a Si substrate. We describe the recipe
for photocathode deposition, and will detail the parameters of the run.
Post-run analysis of the photocathode indicates the presence of significant
damage to the substrate, perhaps due to ion back-bombardment from the residual
beamline gas. While the exact cause of the substrate damage remains unknown, we
describe multiple surface characterization techniques (X-ray fluorescence
spectroscopy, X-ray diffraction, atomic force and scanning electron microscopy)
used to study the interesting morphological and crystallographic features of
the photocathode surface after its use for high current beam production.
Finally, we present a simple model of crystal damage due to ion
back-bombardment, which agrees qualitatively with the distribution of damage on
the substrate surface.Comment: 20 pages, 15 figure
Predominant expression of Alzheimerâs disease-associated BIN1 in mature oligodendrocytes and localization to white matter tracts
BIN1 is not expressed in human brain microglial cells. (A) Immunohistochemical staining of adjacent sections of normal human brain cortex with antibodies against BIN1 or Iba1 reveals that BIN1 immunoreactive cells that are morphologically distinct from microglia. The boxed region is shown at a higher magnification on the right. (B) Single and two-color immunostaining of the human brain using antibodies against BIN1 and CD45 reveals that perivenular CD45-positive cells of the hematopoietic lineage do not express BIN1. (TIFF 4392 kb
Center on Disability Studies eNewsletter, September 2022
Welcome to the September 2022 issue of the CDS eNewsletter. Special highlights in this issue include:
Featured Artist Lynnell Mateaki
RDS Seeks Manuscript Review Board Members
Exhibitor Release #PacRim2023
Introducing Deaf in Government Partnership #PacRim2023
Call for Presentation Proposals #PacRim2023
Legislative Forum Dates | Hawaiʻi DD Council
Hawaiʻi's Path to Employment First Seminar Recording Now Available
2022-2023 CDS Community Advisory Council Introduction
Website Launch Project HoÊ»okuÊ»i V: KĆ«lia i ka NuÊ»u
Fall Announcements with Project HĆkĆ«lani eNewsletterSpecial eNewsletter highlights include: Featured Artist Lynnell Mateaki; RDS Seeks Disability Studies Call for Reviewers; Pac Rim Exhibitor Invitation; Pac Rim Call for Proposals; HawaiÊ»i State Council on Developmental Disabilities Legislative Forums; Presentation HawaiÊ»i's Path to Employment First with Patrick Gartside available; Introducing 2022-2023 Community Advisory Council; Project HoÊ»okuÊ»i V: KĆ«lia i ka NuÊ»u Website Launch; and Project HĆkĆ«lani 2022 Summer eNewsletter Release, HĆkĆ«lani Insider
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