1,753 research outputs found
Fundamental Limits of Thermal-noise Lossy Bosonic Multiple Access Channel
Bosonic channels describe quantum-mechanically many practical communication
links such as optical, microwave, and radiofrequency. We investigate the
maximum rates for the bosonic multiple access channel (MAC) in the presence of
thermal noise added by the environment and when the transmitters utilize
Gaussian state inputs. We develop an outer bound for the capacity region for
the thermal-noise lossy bosonic MAC. We additionally find that the use of
coherent states at the transmitters is capacity-achieving in the limits of high
and low mean input photon numbers. Furthermore, we verify that coherent states
are capacity-achieving for the sum rate of the channel. In the non-asymptotic
regime, when a global mean photon-number constraint is imposed on the
transmitters, coherent states are the optimal Gaussian state. Surprisingly
however, the use of single-mode squeezed states can increase the capacity over
that afforded by coherent state encoding when each transmitter is photon number
constrained individually.Comment: 8 pages, 3 figure
Just Because (Most) Hospitals Are Publishing Charges Does Not Mean Prices Are More Transparent
Background: The Centers for Medicare and Medicaid Services (CMS) recently mandated that all hospitals publish their charge description masters (CDMs) online, in a machine-readable format, by January 1, 2019. In addition, CMS recommended that CDM data be made available in a manner that was consumer friendly and accessible to patients.
Objective: This study aimed to (1) examine all hospitals across the state of Pennsylvania to understand policy compliance and (2) use established metrics to measure accessibility and consumer friendliness of posted CDM data.
Methods: A cross-sectional analysis was conducted to quantify hospital website compliance with the recent CMS policies requiring hospitals to publish their CDM. Data were collected from all Pennsylvania hospital websites. Consumer friendliness was assessed based on searchability, number of website clicks to data, and supplemental educational materials accompanying CDMs such as videos or text.
Results: Most hospitals (189/234, 80.1%) were compliant, but significant variation in data presentation was observed. The mean number of website clicks to the CDM was 3.7 (SD 1.3; range: 1-8). A total of 23.1% of compliant hospitals provided no supplemental educational material with their CDM.
Conclusions: Although disclosure of charges has improved, the data may not be sufficient to meaningfully influence patient decision making
Vertical Resolution of a Seismic Survey in Stratigraphic Sequences less than 100 m Deep in Southeastern Kansas
A 400-m long, 12-fold high-resolution common depth point (CDP) reflection seismic profile was acquired across shallow converging Pennsylvanian strata in the Independence area of southeastern Kansas. One of the principal objectives was to determine practical vertical resolution limits in an excellent shallow seismic-data area with borehole control. The dominant frequency of the CDP stacked data is in excess of 150 Hz based on peak-to-peak measurements. Interference phenomena observed on stacked seismic data incorporated with models derived from log and drill-hole information suggest a practical vertical resolution limit of about 7 m, or one-third of the dominant wavelength. The data suggest conventional rules of thumb describing resolution potential are not accurate when reflectors on shallow, narrow bandwidth data converge rapidly across horizontal distances less than the Fresnel Zone
Factor XI/ADAMTS13 complexes are quantitatively insignificant in human plasma
Reportedly, complexes between factor XI and ADAMTS13 are detected with a commercial ADAMTS13/FXI ELISA kit in plasma and are decreased in thrombotic thrombocytopenic purpura (TTP). Using this kit, control and TTP patient plasma contained varying amounts of signal (25-670% of a reference plasma) but no signal was observed for mixtures of recombinant enzymes, suggesting little interaction. ADAMTS13/FXI complexes were undetectable by immunoprecipitation or gel filtration chromatography in control plasma or mixtures of recombinant proteins. These results suggest that ADAMTS13/FXI complexes are insignificant in plasma and unlikely to affect the function of either protein during normal hemostasis or in TTP
A multicenter retrospective study of childhood brucellosis in Chicago, Illinois from 1986 to 2008
SummaryObjectivesTo determine risk factors in children for the acquisition of Brucella, clinical presentation, treatment, and disease outcomes.MethodsA retrospective multicenter chart review was undertaken of children identified with brucellosis from 1986 to 2008 at three tertiary care centers in Chicago, Illinois, USA. The charts were reviewed for data regarding risk factors for acquisition, clinical presentation, and outcomes.ResultsTwenty-one charts were available for review. The median age was 6.5 years (range 2–14 years); 62% were female. Ethnic background was 67% Hispanic and 24% Arabic. Risk factors included travel to an endemic area (86%), particularly Mexico, and consumption of unpasteurized milk products (76%). Common findings included fever (95%), bacteremia (86%), elevated liver transaminases (80%), constitutional symptoms (76%), splenomegaly (60%), and hepatomegaly (55%). Relapse occurred in three of six subjects started on single drug treatment, but in only one of 15 subjects who started on two or more drugs (p=0.053). No relapses occurred in children whose initial therapy included rifampin or those administered three-drug regimens.ConclusionsBrucella is an infrequent pathogen but should be considered in children with compatible epidemiologic and clinical characteristics. Blood cultures should be obtained, and initial therapy with two or more drugs may decrease the risk of relapse
Influence of a Bi surfactant on Sb incorporation in InAsSb alloys
The influence of using a Bi surfactant during the growth of InAsSb on the composition was examined, and it was found that increasing Bi flux on the surface during growth inhibits the incorporation of Sb. Analysis of the data via a kinetic model of anion incorporation shows that surface Bi acts as a catalyst for InAs formation, thus inhibiting Sb incorporation
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