5,438 research outputs found
Growth of Intermediate-Mass Black Holes in Globular Clusters
We present results of numerical simulations of sequences of binary-single
scattering events of black holes in dense stellar environments. The simulations
cover a wide range of mass ratios from equal mass objects to 1000:10:10 solar
masses and compare purely Newtonian simulations to simulations in which
Newtonian encounters are interspersed with gravitational wave emission from the
binary. In both cases, the sequence is terminated when the binary's merger time
due to gravitational radiation is less than the arrival time of the next
interloper. We find that black hole binaries typically merge with a very high
eccentricity (0.93 < e < 0.95 pure Newtonian; 0.85 < e < 0.90 with
gravitational wave emission) and that adding gravitational wave emission
decreases the time to harden a binary until merger by ~ 30% to 40%. We discuss
the implications of this work for the formation of intermediate-mass black
holes and gravitational wave detection.Comment: 28 pages including 9 figures, submitted to Ap
Diagnostic ultrasound should be performed without upper intensity limits
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135131/1/mp5500.pd
Recent Decisions
Recent Decisions
Admiralty--Maritime Wrongful Death Action--A Maritime Wrongful Death Action for Unseaworthiness Alleging Loss of Support, Services, Society and Funeral Expenses is not Barred by Decedent\u27s Recovery of Damages for Personal Injuries during His Lifetime
Stanley D. Miller
============================
Constitutional Law--Fourth Amendment Search and Seizure--Without Consent, Warrant or Probable Cause, A Roving Patrol Search of a Vehicle Twenty-Five Miles from Border is an Unreasonable Search and Seizure within Meaning of Fourth Amendment
G. Cranwell Montgomery
==============================
Jurisdiction--Securities Exchange Act of 1934--Section 10(b) applies to Fraudulent Transaction in Unlisted Foreign Securities when the Only Conduct within the United States is the Use of the Mails and the Telephone
Douglas Ian Friedma
Generalized Sorting Profile of Alluvial Fans
Alluvial rivers often exhibit self-similar gravel size distributions and abrupt gravel-sand transitions. Experiments suggest that these sorting patterns are established rapidly, but how—and how fast—this convergence occurs in the field is unknown. We examine the establishment of downstream sorting patterns in a kilometer-scale alluvial fan. The sharp transition from canyon to unconfined, channelized fan provides a well-defined boundary condition. The channel changes from deep and entrenched at the fan apex to shallow and depositional over a short distance, exhibiting nonequilibrium behavior. The resulting gravel-fining profile is not self-similar; the particle size distribution narrows until approximate equal mobility is achieved. Downfan, the gravel-sand transition appears to exhibit a self-similar form; field and laboratory data collapse when downstream distance is normalized by the location of the transition. Results suggest a generalized sorting profile for alluvial fans as a consequence of the threshold of motion and nonequilibrium channels
Adverse outcomes and correlates of change in the Short Physical Performance Battery over 36 months in the African American health project
BACKGROUND:
The Short Physical Performance Battery (SPPB) is a well-established measure of lower body physical functioning in older persons but has not been adequately examined in African Americans or younger persons. Moreover, factors associated with changes in SPPB over time have not been reported.
METHODS:
A representative sample of 998 African Americans (49-65 years old at baseline) living in St. Louis, Missouri were followed for 36 months to examine the predictive validity of SPPB in this population and identify factors associated with changes in SPPB. SPPB was calibrated to this population, ranged from 0 (worst) to 12 (best), and required imputation for about 50% of scores. Adverse outcomes of baseline SPPB included death, nursing home placement, hospitalization, physician visits, incident basic and instrumental activity of daily living disabilities, and functional limitations. Changes in SPPB over 36 months were modeled.
RESULTS:
Adjusted for appropriate covariates, weighted appropriately, and using propensity scores to address potential selection bias, baseline SPPB scores were associated with all adverse outcomes except physician visits, and were marginally associated with hospitalization. Declines in SPPB scores were associated with low falls efficacy (b = -1.311), perceived income adequacy (-0.121), older age (-0.073 per year), poor vision (-0.754), diabetes mellitus (-0.565), refusal to report household income (1.48), ever had Medicaid insurance (-0.610), obesity (-0.437), hospitalization in the prior year (-0.521), and kidney disease (-.956).
CONCLUSIONS:
The effect of baseline SPPB on adverse outcomes in this late middle-age African American population confirms reports involving older, primarily white participants. Alleviating deterioration in lower body physical functioning guided by the associated covariates may avoid or delay multiple age-associated adverse outcomes
The influence of octyl beta-D-glucopyranoside on cell lysis induced by ultrasonic cavitation
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98658/1/JAS003482.pd
Intermediate Mass Black Hole Induced Quenching of Mass Segregation in Star Clusters
In many theoretical scenarios it is expected that intermediate-mass black
holes (IMBHs, with masses M ~ 100-10000 solar masses) reside at the centers of
some globular clusters. However, observational evidence for their existence is
limited. Several previous numerical investigations have focused on the impact
of an IMBH on the cluster dynamics or brightness profile. Here we instead
present results from a large set of direct N-body simulations including single
and binary stars. These show that there is a potentially more detectable IMBH
signature, namely on the variation of the average stellar mass between the
center and the half-light radius. We find that the existence of an IMBH
quenches mass segregation and causes the average mass to exhibit only modest
radial variation in collisionally relaxed star clusters. This differs from when
there is no IMBH. To measure this observationally requires high resolution
imaging at the level of that already available from the Hubble Space Telescope
(HST) for the cores of a large sample of galactic globular clusters. With a
modest additional investment of HST time to acquire fields around the
half-light radius, it will be possible to identify the best candidate clusters
to harbor an IMBH. This test can be applied only to globulars with a half-light
relaxation time less than or equal to 1 Gyr, which is required to guarantee
efficient energy equipartition due to two-body relaxation.Comment: 15 pages, 3 figures, ApJ, in pres
Roll plus maneuver load alleviation control system designs for the active flexible wing wind-tunnel model
Three designs for controlling loads while rolling for the Active Flexible Wing (AFW) are discussed. The goal is to provide good roll control while simultaneously limiting the torsion and bending loads experienced by the wing. The first design uses Linear Quadratic Gaussian/Loop Transfer Recovery (LQG/LTR) modern control methods to control roll rate and torsional loads at four different wing locations. The second design uses a nonlinear surface command function to produce surface position commands as a function of current roll rate and commanded roll rate. The final design is a flutter suppression control system. This system stabilizes both symmetric and axisymmetric flutter modes of the AFW
Impending Backlog of Cleft Palate Patients Due to COVID-19
Coronavirus disease 2019 (COVID-19) has placed an unprecedented strain on healthcare systems worldwide, but while high-income countries (HICs) have been able to adapt, low- and middle-income countries (LMICs) have been much slower to do so due to a lack of funding, skilled healthcare providers, equipment, and facilities. The redistribution of resources to combat the pandemic in LMICs has resulted in decreased surgical volumes at local surgical centers as well as a dramatic reduction in the number of humanitarian aid missions. Despite recent global investment in improving the surgical capacities of LMICs, even in the pre-COVID-19 era there was a vast unmet surgical need. This deficit in surgical capacity has grown during the pandemic and it will be a significant struggle to overcome the resulting backlog of patients. A topic of particular concern to the authors is the effect that the pandemic will have on the delivery of time-sensitive surgical care to patients with cleft palate deformities as delay in providing care can have enormous physical and psychosocial consequences. This paper draws increased attention to the lasting impact that the COVID-19 pandemic may have on cleft palate patients in LMICs. SSRN Pre-print server link: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3898055
Three-year measured weight change in the African American health study
OBJECTIVE: This study examines 3-year weight change in African Americans.
METHOD: Nine hundred and ninety-eight participants 49 to 65 years old were assessed at baseline and 3 years later. Weight was measured, and weight change was defined as clinically meaningful increases or decreases (+/- 5 kg). Potential risk factors were investigated using multinomial logistic regression.
RESULTS: In-home measured weights were available for 752 participants (75%): 504 (67%) had stable weights, 131 (17%) gained more than 5 kg, and 117 (16%) lost more than 5 kg. Among all participants, the risks for weight gains were cancer, chronic obstructive pulmonary disease, lower income, and Medicaid status; the risks for weight losses were angina, cancer, high measured systolic blood pressure, asthma, and physical inactivity. Sex-stratified analyses reveal differences involving age, socioeconomic status, cancer, blood pressure, and lower body function.
DISCUSSION: Three-year weight changes in middle-aged African Americans were frequent and significantly associated with several risk factors
- …