854 research outputs found
Prompt Electromagnetic Transients from Binary Black Hole Mergers
Binary black hole (BBH) mergers provide a prime source for current and future
interferometric GW observatories. Massive BBH mergers may often take place in
plasma-rich environments, leading to the exciting possibility of a concurrent
electromagnetic (EM) signal observable by traditional astronomical facilities.
However, many critical questions about the generation of such counterparts
remain unanswered. We explore mechanisms that may drive EM counterparts with
magnetohydrodynamic simulations treating a range of scenarios involving
equal-mass black-hole binaries immersed in an initially homogeneous fluid with
uniform, orbitally aligned magnetic fields. We find that the time development
of Poynting luminosity, which may drive jet-like emissions, is relatively
insensitive to aspects of the initial configuration. In particular, over a
significant range of initial values, the central magnetic field strength is
effectively regulated by the gas flow to yield a Poynting luminosity of
, with BBH mass
scaled to and ambient density . We also calculate the
direct plasma synchrotron emissions processed through geodesic ray-tracing.
Despite lensing effects and dynamics, we find the observed synchrotron flux
varies little leading up to merger.Comment: 22 pages, 21 figures; additional reference + clarifying text added to
match published versio
ALMA Observations of Circumnuclear Disks in Early Type Galaxies: 12CO(2-1) and Continuum Properties
We present results from an Atacama Large Millimeter/submillimeter Array
(ALMA) Cycle 2 program to map CO(2-1) emission in nearby early-type galaxies
(ETGs) that host circumnuclear gas disks. We obtained resolution
Band 6 observations of seven ETGs selected on the basis of dust disks in Hubble
Space Telescope images. We detect CO emission in five at high signal-to-noise
ratio with the remaining two only faintly detected. All CO emission is
coincident with the dust and is in dynamically cold rotation. Four ETGs show
evidence of rapid central rotation; these are prime candidates for
higher-resolution ALMA observations to measure the black hole masses. In this
paper we focus on the molecular gas and continuum properties. Total gas masses
and H column densities for our five CO-bright galaxies are on average
and cm over the kpc-scale
disks, and analysis suggests that these disks are stabilized against
gravitational fragmentation. The continuum emission of all seven galaxies is
dominated by a central, unresolved source, and in five we also detect a
spatially extended component. The 230 GHz nuclear continua are modeled as
power laws ranging from to within the
observed frequency band. The extended continuum profiles of the two
radio-bright (and CO-faint) galaxies are roughly aligned with their radio jet
and suggests resolved synchrotron jets. The extended continua of the CO-bright
disks are coincident with optically thick dust absorption and have spectral
slopes that are consistent with thermal dust emission.Comment: 20 pages, 10 figures; accepted for publication in Ap
Quantum cascade laser-based mid-infrared spectrochemical imaging of tissue and biofluids
Mid-infrared spectroscopic imaging is a rapidly emerging technique in biomedical research and clinical diagnostics that takes advantage of the unique molecular fingerprint of cells, tissue and biofluids to provide a rich biochemical image without the need for staining. Spectroscopic analysis allows for the objective classification of biological material at a molecular level.1 This “label free” molecular imaging technique has been applied to histology, cytology, surgical pathology, microbiology and stem cell research, and can be used to detect subtle changes to the genome, proteome and metabolome.2,3,4 The new wealth of biochemical information made available by this technique has the distinct potential to improve cancer patient outcome through the identification of earlier stages of disease, drug resistance, new disease states and high-risk populations.4 However, despite the maturity of this science, instrumentation that provide increased sample throughput, improved image quality, a small footprint, low maintenance and require minimal spectral expertise are essential for clinical translation
Anatomy of the binary black hole recoil: A multipolar analysis
We present a multipolar analysis of the gravitational recoil computed in
recent numerical simulations of binary black hole (BH) coalescence, for both
unequal masses and non-zero, non-precessing spins. We show that multipole
moments up to and including l=4 are sufficient to accurately reproduce the
final recoil velocity (within ~2%) and that only a few dominant modes
contribute significantly to it (within ~5%). We describe how the relative
amplitudes, and more importantly, the relative phases, of these few modes
control the way in which the recoil builds up throughout the inspiral, merger,
and ringdown phases. We also find that the numerical results can be reproduced
by an ``effective Newtonian'' formula for the multipole moments obtained by
replacing the radial separation in the Newtonian formulae with an effective
radius computed from the numerical data. Beyond the merger, the numerical
results are reproduced by a superposition of three Kerr quasi-normal modes
(QNMs). Analytic formulae, obtained by expressing the multipole moments in
terms of the fundamental QNMs of a Kerr BH, are able to explain the onset and
amount of ``anti-kick'' for each of the simulations. Lastly, we apply this
multipolar analysis to help explain the remarkable difference between the
amplitudes of planar and non-planar kicks for equal-mass spinning black holes.Comment: 28 pages, 20 figures, submitted to PRD; v2: minor revisions from
referee repor
Patients’ Perceptions of Pharmacist Intervention Through Pre-Screened Medication Therapy Management Service
Background: The continued challenge of time commitment in a community pharmacy setting is reported by pharmacists as the single largest setback in providing quality patient care. Additionally, when efforts are made by pharmacists to intervene on a patient’s therapy through medication therapy management (MTM), patient “no shows” further challenge an already busy community pharmacy world. Many studies show the value of a pharmacist-patient relationship. However, continued barriers prevent the value of this relationship to take full effect. While numerous methods of comprehensive medication review take place, the issue of establishing a model that best suits the needs of community pharmacy patients still exists.
Statement of the Problem: To assess patients’ perceptions of pharmacist intervention through a pre-screened medication therapy management service at prescription pick-up.
Description of Methodology: This study utilized a nonprobability convenience sampling of MTM participants at a local community pharmacy pickup for research. A questionnaire was designed to assess patients’ perceptions prior to and after the pharmacist intervention. All adult patients willing to participate in MTM services were included. After the MTM intervention, participants were encouraged to complete the questionnaire at home and mail it back to the pharmacy. The questionnaires were then collected from the pharmacy for review and data was analyzed with SPSS software.
Results: Reported increased patient satisfaction and knowledge by survey following the MTM intervention. Unfortunately, the results were insignificant and the study did not achieve ideal power.
Conclusions: The descriptive statistical results enumerated in this study do not reveal any applicable trends relating to the use of MTM services at-large. Despite these findings, however, all patients who commented on the intervention provided positive feedback. Further research is encouraged to appropriately assess the value of pharmacist-delivered MTM at prescription pick-up
Hip Anatomy and Ontogeny of Lower Limb Musculature in Three Species of Nonhuman Primates
The hip region is examined to determine what aspects of musculoskeletal anatomy are precociously developed in primate species with highly specialized modes of locomotion. Muscles of the hind limb were removed and weighed in each specimen, and the hip joint of selected specimens was studied in stained serial sections. No perinatal differences among species are evident, but in adults, the hip joint of Galago moholi (a leaping specialist) appears to have proportionally thick articular cartilage (relative to the subchondral plate) compared to two species of cheirogaleids. Muscle mass distribution in the hind limbs confirms previous observations that the quadriceps femoris muscle is especially large in Galago (in percent mass of the entire hind limb), while the hip region is smaller compared to the more quadrupedal cheirogaleids. Across age groups, the species with the least specialized locomotion as adults, Cheirogaleus medius, shows little or no change in proximal to distal percentage distribution of muscle mass. Galago has a larger percentage mass gain in the thigh. We suggest that muscle mass gain to specific limb segments may be a critical milestone for primates with extremely specialized modes of locomotion
A Precision Measurement of the Mass of the Black Hole in NGC 3258 from High-Resolution ALMA Observations of its Circumnuclear Disk
We present resolution Atacama Large
Millimeter/submillimeter Array (ALMA) CO(21) imaging of the arcsecond-scale
( pc) dusty molecular disk in the giant elliptical galaxy NGC
3258. The data provide unprecedented resolution of cold gas disk kinematics
within the dynamical sphere of influence of a supermassive black hole,
revealing a quasi-Keplerian central increase in projected rotation speed rising
from 280 km s at the disk's outer edge to km s near the
disk center. We construct dynamical models for the rotating disk and fit
beam-smeared model CO line profiles directly to the ALMA data cube. Our models
incorporate both flat disks and tilted-ring disks that provide a better fit of
the mildly warped structure in NGC 3258. We show that the exceptional angular
resolution of the ALMA data makes it possible to infer the host galaxy's mass
profile within pc solely from the ALMA CO kinematics, without relying
on optical or near-infrared imaging data to determine the stellar mass profile.
Our model therefore circumvents any uncertainty in the black hole mass that
would result from the substantial dust extinction in the galaxy's central
region. The best model fit yields
with a statistical model-fitting uncertainty of just 0.18\%, and systematic
uncertainties of 0.62\% from various aspects of the model construction and 12\%
from uncertainty in the distance to NGC 3258. This observation demonstrates the
full potential of ALMA for carrying out highly precise measurements of
in early-type galaxies containing circumnuclear gas disksComment: Accepted for publication in ApJ. 32 pages, 22 figure
MEASUREMENT OF THE BLACK HOLE MASS IN NGC 1332 FROM ALMA OBSERVATIONS AT 0.044 ARCSECOND RESOLUTION
We present Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 3 observations of CO(2-1) emission from the circumnuclear disk in the E/S0 galaxy NGC 1332 at 0.″044 resolution. The disk exhibits regular rotational kinematics and central high-velocity emission (±500 km s ) consistent with the presence of a compact central mass. We construct models for a thin, dynamically cold disk in the gravitational potential of the host galaxy and black hole and fit the beam-smeared model line profiles directly to the ALMA data cube. Model fits successfully reproduce the disk kinematics out to r = 200 pc. Fitting models just to spatial pixels within projected r = 50 pc of the nucleus (two times larger than the black hole's gravitational radius of influence), we find M =(6.64 ) × 10 M . This observation demonstrates ALMA's powerful capability to determine the masses of supermassive black holes by resolving gas kinematics on small angular scales in galaxy nuclei. -1 +0.65 8 BH -0.63
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Predicting the Impact of Vaccination on the Transmission Dynamics of Typhoid in South Asia: A Mathematical Modeling Study
Background: Modeling of the transmission dynamics of typhoid allows for an evaluation of the potential direct and indirect effects of vaccination; however, relevant typhoid models rooted in data have rarely been deployed. Methodology/Principal Findings We developed a parsimonious age-structured model describing the natural history and immunity to typhoid infection. The model was fit to data on culture-confirmed cases of typhoid fever presenting to Christian Medical College hospital in Vellore, India from 2000–2012. The model was then used to evaluate the potential impact of school-based vaccination strategies using live oral, Vi-polysaccharide, and Vi-conjugate vaccines. The model was able to reproduce the incidence and age distribution of typhoid cases in Vellore. The basic reproductive number (R0) of typhoid was estimated to be 2.8 in this setting. Vaccination was predicted to confer substantial indirect protection leading to a decrease in the incidence of typhoid in the short term, but (intuitively) typhoid incidence was predicted to rebound 5–15 years following a one-time campaign. Conclusions/Significance: We found that model predictions for the overall and indirect effects of vaccination depend strongly on the role of chronic carriers in transmission. Carrier transmissibility was tentatively estimated to be low, consistent with recent studies, but was identified as a pivotal area for future research. It is unlikely that typhoid can be eliminated from endemic settings through vaccination alone
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