379 research outputs found
Composite Scores for Transplant Center Evaluation: A New Individualized Empirical Null Method
Risk-adjusted quality measures are used to evaluate healthcare providers
while controlling for factors beyond their control. Existing healthcare
provider profiling approaches typically assume that the risk adjustment is
perfect and the between-provider variation in quality measures is entirely due
to the quality of care. However, in practice, even with very good models for
risk adjustment, some between-provider variation will be due to incomplete risk
adjustment, which should be recognized in assessing and monitoring providers.
Otherwise, conventional methods disproportionately identify larger providers as
outliers, even though their provider effects need not be "extreme.'' Motivated
by efforts to evaluate the quality of care provided by transplant centers, we
develop a composite evaluation score based on a novel individualized empirical
null method, which robustly accounts for overdispersion due to unobserved risk
factors, models the marginal variance of standardized scores as a function of
the effective center size, and only requires the use of publicly-available
center-level statistics. The evaluations of United States kidney transplant
centers based on the proposed composite score are substantially different from
those based on conventional methods. Simulations show that the proposed
empirical null approach more accurately classifies centers in terms of quality
of care, compared to existing methods
Unconformities and Age Relationships, Tongue River and Older Members of the Fort Union Formation (Paleocene), Western Williston Basin, U.S.A.
An unconformable relationship is observed within the Paleocene Fort Union Formation in the western Williston Basin at the contact between the Tongue River Member and the underlying Lebo and Ludlow Members. Isotopic dates and pollen biozone data reported here are integrated with previously published data. A new correlation of these facies results in a revised history of localized depositional and tectonic events. One unconformity occurs at this lithological contact in the Pine Hills (PH), Terry Badlands (TB), and Ekalaka (E) areas west of the Cedar Creek anticline (CCA), and another unconformity occurs at the same lithological contact in the Little Missouri River (LMR) area east of the CCA. The two unconformities differ in age by about two million years. The older is the U2 and the younger is the U3 , which initially were recognized in the Ekalaka area of southeastern Montana (Belt et al., 2002). The U2 crops out in the TB, PH, and E areas, where at least 85 m of Tongue River strata bearing palynomorphs characteristic of biozone P-3 are found above the unconformity. Radiometric dates from strata (bearing palynomorphs characteristic of biozone P-2) below the U2 range in age from 64.0 to 64.73 Ma. The U2 unconformity west of the CCA thus occurs in strata near the base of the lower P-3 biozone.
The U3 crops out in the LMR area (east of the CCA), where only 13 m of strata characterized by the P-3 pollen biozone occur above it. Radiometric dates from an ash \u3c1 m above the U3 in that area range in age from 61.03 to 61.23 Ma, and the P-3/P-4 pollen biozone boundary is located 13 m above the ashes. The U3 thus occurs in strata characterized by upper parts of the P-3 pollen biozone east of the CCA. The U3 is also identifiable in the middle of the ca. 200 m-thick Tongue River Member west of the CCA, where mammal sites 40 to 80 m above it are Tiffanian-3 in age. The strata below this unconformity are tilted gently to the northwest; strata above the unconformity are flat lying. This mid Tongue River unconformity probably correlates with the unconformity at the base of the Tongue River Member in the LMR area east of the CCA, where a Ti-2 mammal site (the âX-Xâ locality) occurs \u3c10 m above it.
Depositional and tectonic events can be summarized using North American Mammal Age nomenclature as a relative time scale. From latest Cretaceous through Puercan time, paleodrainage was toward the east or southeast, in the direction of the Cannonball Sea. The Black Hills did not serve as an obstruction at that time. During early Torrejonian time, the Miles City arch (MCA) and Black Hills were uplifted and partially eroded, leading to the U2 unconformity. When deposition resumed, paleodrainages shifted to a northeasterly course. During middle and late Torrejonian time, facies of the lower Tongue River (âDominyâ) sequence and the Ekalaka Member of the Fort Union Formation were deposited in the middle of a subbasin between the MCA and the CCA. Simultaneously, smectite-rich components of the Ludlow Member were being deposited east of the CCA. During latest Torrejonian time, uplift of the Black Hills tilted the âDominyâ sequence toward the northwest and local erosion led to the U3 unconformity. Following this tilting, during Tiffanian time, deposition of the upper Tongue River (âKnoblochâ) sequence shows continuity from western North Dakota across eastern Montana and into the northern Powder River Basin
Embedding initial data for black hole collisions
We discuss isometric embedding diagrams for the visualization of initial data
for the problem of the head-on collision of two black holes. The problem of
constructing the embedding diagrams is explicitly presented for the best
studied initial data, the Misner geometry. We present a partial solution of the
embedding diagrams and discuss issues related to completing the solution.Comment: (27pp text, 11 figures
Evidence for Marine Influence on a Low-Gradient Coastal Plain: Ichnology and Invertebrate Paleontology of the Lower Tongue River Member (Fort Union Formation, Middle Paleocene), Western Williston Basin, U.S.A.
The Paleocene Tongue River Member of the Fort Union Formation contains trace-fossil associations indicative of marine influence in otherwise freshwater facies. The identified ichnogenera include: Arenicolites, Diplocraterion, Monocraterion, Ophiomorpha, Rhizocorallium, Skolithos linearis, Teichichnus, Thalassinoides, and one form of uncertain affinity. Two species of the marine diatom Coscinodiscus occur a few meters above the base of the member. The burrows occur in at least five discrete, thin, rippled, fine-grained sandstone beds within the lower 85 m of the member west of the Cedar Creek anticline (CCA) in the Signal Butte, Terry Badlands, and Pine Hills areas. Two discrete burrowed beds are found in the lower 10 m of the member east of the CCA in the little Missouri River area.
Abundant freshwater ostracodes include Bisulcocypridea arvadensis, Candona, and Cypridopsis. Freshwater bivalves include Plesielliptio and Pachydon mactriformis. We recognize four fossil assemblages that represent fluvio-lacustrine, proximal estuarine, central estuarine, and distal estuarine environments. Biostratal alternations between fresh- and brackish-water assemblages indicate that the Tongue River Member was deposited along a low-gradient coastal plain that was repeatedly inundated from the east by the Cannonball Sea.
The existence of marine-influenced beds in the Tongue River Member invalidates the basis for the Slope Formation
Intelligent Transportation Systems Strategic Plan (Phase I Report)
This interim report on an Intelligent Transportation Systems Strategic (ITS) Plan has been developed as documentation of the process of offering a vision for ITS and recommending an outline for organizational structure, infrastructure, and long-term planning for ITS in Kentucky. This plan provides an overview of the broad scope of ITS and relationships between various Intelligent Vehicle Highway Systems (IVHS) functional areas and ITS user service areas. Three of the functional areas of ITS have been addressed in this interim report with sections devoted to mission, vision, goals, and potential technology applications. Within each of the three areas, recommendations have been made for applications and technologies for deployment. A more formalized business plan for will be developed to recommend specific projects for implementation. Those three functional areas are 1) Advanced Rural Transportation Systems (ARTS), 2) Advanced Traveler Information Systems (ATIS), and 3) Commercial Vehicle Operations (CVO).
A survey of other states was conducted to determine the status of the development of ITS strategic plans. Information received from the 11 states that had completed strategic plans was used to determine the overall approach taken in development of the plans and to evaluate the essential contents of the reports for application in Kentucky.
Kentucky\u27s ITS Strategic Plan evolved from an early decision by representatives of the Kentucky Transportation Cabinet (KyTC) to formalize the procedure by requesting the Kentucky Transportation Center to prepare a work plan outlining the proposed tasks. Following several introductory meetings of the Study Advisory Committee, additional focus group meetings were held with various transportation representatives to identify ITS issues of importance. Results from these meetings were compiled and used as input to the planning process for development of the Strategic Plan components of ARTS and ATIS.
The development of a strategic plan for Commercial Vehicle Operations originated from a different procedure than did the other functional areas of ITS. As part of well-developed commercial vehicle activities through the ITS-related programs of Advantage I-75 and CVISN, Kentucky has become a national leader in this area and has developed a strategic plan of advanced technology applications to commercial vehicles. The strategic plan for Commercial Vehicle Operations was developed out of the convergence of several parallel processes in Kentucky. Empower Kentucky work teams had met over a two-year period to develop improved and more efficient processes for CVO in Kentucky. Their conclusions and recommendations encouraged the further activities of the Kentucky ITS/CVO working group that first convened in the summer of 1996. In an effort to conceptually organize the various ITS/CVO activities in Kentucky, and as a commitment to the CVISN Mainstreaming plan, an inclusive visioning exercise was held in early 1997. Out of this exercise emerged the six critical vision elements that guided the CVO strategic plan.
The remaining functional areas to be included in the ITS Strategic Plan will be addressed in the second phase of this study. Those areas are Advanced Traffic Management Systems (ATMS), Advanced Vehicle Control Systems (AVCS), and Advanced Public Transportation Systems (APTS). It is anticipated that a process similar to that developed for the first phase of this study will continue
Response to treatment in a prospective national infantile spasms cohort
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134499/1/ana24594.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134499/2/ana24594_am.pd
On the selection of AGN neutrino source candidates for a source stacking analysis with neutrino telescopes
The sensitivity of a search for sources of TeV neutrinos can be improved by
grouping potential sources together into generic classes in a procedure that is
known as source stacking. In this paper, we define catalogs of Active Galactic
Nuclei (AGN) and use them to perform a source stacking analysis. The grouping
of AGN into classes is done in two steps: first, AGN classes are defined, then,
sources to be stacked are selected assuming that a potential neutrino flux is
linearly correlated with the photon luminosity in a certain energy band (radio,
IR, optical, keV, GeV, TeV). Lacking any secure detailed knowledge on neutrino
production in AGN, this correlation is motivated by hadronic AGN models, as
briefly reviewed in this paper.
The source stacking search for neutrinos from generic AGN classes is
illustrated using the data collected by the AMANDA-II high energy neutrino
detector during the year 2000. No significant excess for any of the suggested
groups was found.Comment: 43 pages, 12 figures, accepted by Astroparticle Physic
Response to second treatment after initial failed treatment in a multicenter prospective infantile spasms cohort
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135085/1/epi13557_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135085/2/epi13557.pd
BU Canis Minoris -- the Most Compact Known Flat Doubly Eclipsing Quadruple System
We have found that the 2+2 quadruple star system BU CMi is currently the most
compact quadruple system known, with an extremely short outer period of only
121 days. The previous record holder was TIC 219006972 (Kostov et al. 2023),
with a period of 168 days. The quadruple nature of BU CMi was established by
Volkov et al. (2021), but they misidentified the outer period as 6.6 years. BU
CMi contains two eclipsing binaries (EBs), each with a period near 3 days, and
a substantial eccentricity of about 0.22. All four stars are within about 0.1
solar mass of 2.4 solar masses. Both binaries exhibit dynamically driven
apsidal motion with fairly short apsidal periods of about 30 years, thanks to
the short outer orbital period. The outer period of 121 days is found both from
the dynamical perturbations, with this period imprinted on the eclipse timing
variations (ETV) curve of each EB by the other binary, and by modeling the
complex line profiles in a collection of spectra. We find that the three
orbital planes are all mutually aligned to within 1 degree, but the overall
system has an inclination angle near 83.5 degrees. We utilize a complex
spectro-photodynamical analysis to compute and tabulate all the interesting
stellar and orbital parameters of the system. Finally, we also find an
unexpected dynamical perturbation on a timescale of several years whose origin
we explore. This latter effect was misinterpreted by Volkov et al. (2021) and
led them to conclude that the outer period was 6.6 years rather than the 121
days that we establish here.Comment: 19 pages, 8 pages, accepted to MNRA
Planet Occurrence within 0.25 AU of Solar-type Stars from Kepler
We report the distribution of planets as a function of planet radius (R_p),
orbital period (P), and stellar effective temperature (Teff) for P < 50 day
orbits around GK stars. These results are based on the 1,235 planets (formally
"planet candidates") from the Kepler mission that include a nearly complete set
of detected planets as small as 2 Earth radii (Re). For each of the 156,000
target stars we assess the detectability of planets as a function of R_p and P.
We also correct for the geometric probability of transit, R*/a. We consider
first stars within the "solar subset" having Teff = 4100-6100 K, logg =
4.0-4.9, and Kepler magnitude Kp < 15 mag. We include only those stars having
noise low enough to permit detection of planets down to 2 Re. We count planets
in small domains of R_p and P and divide by the included target stars to
calculate planet occurrence in each domain. Occurrence of planets varies by
more than three orders of magnitude and increases substantially down to the
smallest radius (2 Re) and out to the longest orbital period (50 days, ~0.25
AU) in our study. For P < 50 days, the radius distribution is given by a power
law, df/dlogR= k R^\alpha. This rapid increase in planet occurrence with
decreasing planet size agrees with core-accretion, but disagrees with
population synthesis models. We fit occurrence as a function of P to a power
law model with an exponential cutoff below a critical period P_0. For smaller
planets, P_0 has larger values, suggesting that the "parking distance" for
migrating planets moves outward with decreasing planet size. We also measured
planet occurrence over Teff = 3600-7100 K, spanning M0 to F2 dwarfs. The
occurrence of 2-4 Re planets in the Kepler field increases with decreasing
Teff, making these small planets seven times more abundant around cool stars
than the hottest stars in our sample. [abridged]Comment: Submitted to ApJ, 22 pages, 10 figure
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