We present measurements of bulk properties of the matter produced in Au+Au collisions at $\sqrt{s}$$_ {NN}$= 7.7, 11.5, 19.6, 27, and 39 GeV using identified hadrons (π±, K±, p, and $\bar{p}$) from ...the STAR experiment in the Beam Energy Scan (BES) Program at the Relativistic Heavy Ion Collider (RHIC). Midrapidity (| y | < 0.1) results for multiplicity densities dN / dy, average transverse momenta $\langle$pT$\rangle$, and particle ratios are presented. The chemical and kinetic freeze-out dynamics at these energies are discussed and presented as a function of collision centrality and energy. These results constitute the systematic measurements of bulk properties of matter formed in heavy-ion collisions over a broad range of energy (or baryon chemical potential) at RHIC.
Abstract
Background
Prior analyses have demonstrated that persistent atrial fibrillation (PeAF) is associated with higher healthcare costs than paroxysmal AF (pAF) or permanent AF (PermAF). While ...clinical classification of AF is often inaccurate, assessing AF burden from cardiac implantable electronic devices (CIEDs) provides an opportunity to more accurately assess the mechanisms of cost differentials by type of AF.
Objective
To assess the rates of AF-specific healthcare interventions among patients with device detected pAF, PeAF and PermAF.
Methods
Using the de-identified Optum Clinformatics U.S. claims database (2015 to 2020) linked with the Medtronic CareLink database, we identified patients with newly implanted CIEDs that transmitted data 6 months post-implant (baseline period). Device monitoring data during baseline was utilized to stratify patients by AF burden category: pAF (at least one day with >5m AF but <7d with >23h AF), PeAF (at least 7 consecutive days with >23h AF) or PermAF (all days with >23h AF or >95% AF burden). Annualized rates of AF-specific interventions (cardioversions, ablations, hospitalizations for antiarrhythmic drug AAD loads, oral anticoagulation OAC prescription and AAD prescription) during follow-up were analyzed from insurance claims. Analyses were adjusted for geographical region, insurance type, CHA2DS2-VASc Score, and implant year.
Results
Of the 21,391 patients (72.9±10.9 yrs; 56.3% male) analyzed, 7,798 (36.5%) had device-detected AF. Among these, 5,966 (76.5%) were pAF (avg burden 2.9±8.6%), 1,145 (14.7%) were PeAF (avg burden 47.2±29.9%), and 687 (8.8%) were PermAF (avg burden 99.3±0.7%). Compared to patients with pAF, those with PeAF had a higher adjusted ratio of cardioversions, hospitalizations for new AAD initiation, OAC prescription and AAD prescription. Patients with PeAF also had higher adjusted rates of ablations, cardioversions, hospitalizations for new AAD initiation, and AAD prescriptions than those with PermAF. Compared to patients with pAF, those with PermAF had a lower adjusted rate of ablation, hospitalization for new AAD load and AAD prescription, but a higher rate of OAC prescription (fig).
Conclusion
In a real-world cohort, patients with CIED-detected PeAF had higher rates of cardioversions, hospitalizations for AAD initiation, and AAD prescriptions than those with CIED-detected pAF and PermAF. The higher intensity of observed physician-driven interventions may be a potential driver of the increased cost associated with PeAF.Figure
In an earlier publication we developed a bubble model, based on our evolution of the original ideas of van Hove which we concurred with over two decades ago; namely, that if a quark–gluon plasma is ...produced in a high energy heavy ion collider, then some of its hadronization products could be emitted from small bubbles localized in phase space containing plasma. In this paper we refined the model to become a parton bubble model in which each localized bubble contains initially 3–4 partons which are almost entirely gluons forming a gluon hot spot. We greatly expanded the transverse momentum interval investigated and thus are able to treat recombination effects within each bubble. We again utilize two-particle correlations as a sensitive method for detecting the average bubble substructure. In this manuscript we make many predictions for angular correlations detectable at RHIC, which will be later modified to LHC conditions. A quantitative test of the multi-bubble substructure assumed in the model was made by comparing with precision STAR Collaboration correlation analyses. Good quantitative agreement was obtained. Some early available low precision correlation analyses is qualitatively explained.
Abstract
Funding Acknowledgements
Type of funding sources: None.
Background
There are limited data on the mechanisms of increased healthcare costs among patients with atrial fibrillation (AF). ...Differences in healthcare expenditures at various sites of service may provide mechanistic insight into the cost differentials between patients with and without AF.
Objective
To assess for associations between sites of service and healthcare costs among patients with and without device detected AF (ddAF).
Methods
Using the de-identified Optum® Clinformatics® U.S. claims database (2015 to 2020) linked with the Medtronic CareLink® database, we identified CIED patients that transmitted data ≥6 months post-implant (baseline period). Annualized per-patient costs during follow-up, subdivided by site of service, were compared between patients with and without ddAF and adjusted to 2020 US Dollars. Analyses were adjusted for geographical region, insurance type, CHA2DS2-VASc Score, and implant year. The ten most common hospitalization diagnosis-related groups (DRG) were analyzed in patients with and without ddAF.
Results
Of the 21,391 patients (72.9±10.9 yrs; 56.3% male) analyzed, 7,798 (36.5%) had ddAF. Compared to patients without ddAF, those with ddAF had higher annualized total healthcare costs (adjusted cost ratio (CR) 1.21 (1.16-1.25); p<0.001). There were no differences in clinic health expenditures between patients with and without ddAF (adjusted CR 1.01 (0.98-1.04); p=0.63). Patients with ddAF had higher inpatient hospitalization (adjusted CR 1.29 (1.21-1.37); p<0.001), outpatient hospitalization (adjusted CR 1.20 (1.15-1.24); p<0.001), long-term care facility (adjusted CR 1.39 (1.24-1.55); p<0.001), and total pharmacy (adjusted CR 1.14 (1.10-1.19); p<0.001) costs than patients without ddAF (fig). Heart failure hospitalizations accounted for the highest percentage of analyzed DRGs. Patients with and without ddAF had similar percentages of DRGs for heart failure hospitalization (ddAF: 41.9%; no ddAF: 41.3%). Of the hospitalization DRGs analyzed, 9.7% were for arrhythmia-related hospitalizations in the ddAF cohort.
Conclusion
Increased hospitalization, long term care facility, and pharmacy costs are largely responsible for the healthcare cost differential between patients with and without ddAF. It is likely that arrhythmia-related hospitalizations account for a significant portion of the increased cost associated with ddAF. Further research into specific interventions that occur at various sites of service, which produce increased cost among patients with ddAF, is needed.
Abstract
Funding Acknowledgements
Type of funding sources: None.
Background
Previous research on atrial fibrillation (AF)-related healthcare cost is limited by claims-derived categorization of AF ...diagnosis and does not assess for incremental differences in cost based on degree of AF burden.
Objective
To directly assess the incremental cost of device detected AF (ddAF), and compare relative costs among cohorts with no AF, paroxysmal AF (pAF), persistent AF (PeAF), and permanent AF (PermAF) in patients with cardiac implantable electronic devices (CIED) capable of sensitive and continuous atrial arrhythmia detection.
Methods
Using the de-identified Optum® Clinformatics® U.S. claims database (2015 to 2020) linked with the Medtronic CareLink® database, we identified CIED patients that transmitted data ≥6 months post-implant (baseline period). Annualized per-patient costs in follow up were analyzed from insurance claims and adjusted to 2020 US Dollars. Total costs were compared between patients with no AF and those with device detected pAF, PeAF and PermAF. Analyses were adjusted for geographical region, insurance type, CHA2DS2-VASc Score, and implant year.
Results
Of the 21,391 patients (72.9±10.9 yrs; 56.3% male) analyzed, 7,798 (36.5%) had ddAF. Among these, 5,966 (76.5%) were pAF (avg burden 2.9±8.6%), 1,145 (14.7%) were PeAF (avg burden 47.2±29.9%), and 687 (8.8%) were PermAF (avg burden 99.3±0.7%). Patients with ddAF had higher overall annualized total healthcare costs than those without ddAF (fig). The incremental annualized increased cost in those with ddAF was $12,789 ± $161,749 per patient. Patients with pAF, PeAF and PermAF all had higher adjusted healthcare costs than those without AF (p for all <0.001). Patients with PeAF and PermAF both had higher total adjusted costs than patients with pAF. In addition, patients with PeAF had higher healthcare costs than those with PermAF (fig).
Conclusions
In the present analysis of CIED patients, ddAF was associated with increased healthcare costs after adjustment for clinical and demographic covariates. Among those with ddAF, patients with PeAF had the highest healthcare costs. Preventing development of AF, and progression to PeAF, may reduce healthcare costs.
In this study, we present results of analyses of two-pion interferometry in Au+Au collisions at √sNN = 7.7, 11.5, 19.6, 27, 39, 62.4, and 200 GeV measured in the STAR detector as part of the RHIC ...Beam Energy Scan program. The extracted correlation lengths (HBT radii) are studied as a function of beam energy, azimuthal angle relative to the reaction plane, centrality, and transverse mass (mT) of the particles. The azimuthal analysis allows extraction of the eccentricity of the entire fireball at kinetic freeze-out. The energy dependence of this observable is expected to be sensitive to changes in the equation of state. A new global fit method is studied as an alternate method to directly measure the parameters in the azimuthal analysis. The eccentricity shows a monotonic decrease with beam energy that is qualitatively consistent with the trend from all model predictions and quantitatively consistent with a hadronic transport model.
Here, we present measurements of three-particle correlations for various harmonics in Au+Au collisions at energies ranging from √sNN=7.7 to 200 GeV using the STAR detector. The quantity < ...cos(mΦ1+nΦ2–(m+n)Φ3) >, with Φ being the azimuthal angles of the particles is evaluated as a function of √sNN, collision centrality, transverse momentum, pT, pseudorapidity difference, Δη, and harmonics (m and n). These data provide detailed information on global event properties such as the three-dimensional structure of the initial overlap region, the expansion dynamics of the matter produced in the collisions, and the transport properties of the medium. A strong dependence on Δη is observed for most harmonic combinations, which is consistent with breaking of longitudinal boost invariance. An interesting energy dependence is observed when one of the harmonics m,n, or m+n is equal to two, for which the correlators are dominated by the two-particle correlations relative to the second-harmonic event plane. These measurements can be used to constrain models of heavy-ion collisions over a wide range of temperature and baryon chemical potential.
The forward time projection chamber in STAR Ackermann, K.H.; Bieser, F.; Brady, F.P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2003, Letnik:
499, Številka:
2
Journal Article
Recenzirano
Two cylindrical forward TPC detectors are described which were constructed to extend the phase space coverage of the STAR experiment to the region 2.5<|
η|<4.0. For optimal use of the available space ...and in order to cope with the high track density of central Au+Au collisions at RHIC, a novel design was developed using radial drift in a low diffusion gas. From prototype measurements a 2-track resolution of 1–
2
mm
is expected.
We review the most important experimental results from the first three years of nucleus–nucleus collision studies at RHIC, with emphasis on results from the STAR experiment, and we assess their ...interpretation and comparison to theory. The theory-experiment comparison suggests that central Au + Au collisions at RHIC produce dense, rapidly thermalizing matter characterized by: (1) initial energy densities above the critical values predicted by lattice QCD for establishment of a quark–gluon plasma (QGP); (2) nearly ideal fluid flow, marked by constituent interactions of very short mean free path, established most probably at a stage preceding hadron formation; and (3) opacity to jets. Many of the observations are consistent with models incorporating QGP formation in the early collision stages, and have not found ready explanation in a hadronic framework. However, the measurements themselves do not yet establish unequivocal evidence for a transition to this new form of matter. The theoretical treatment of the collision evolution, despite impressive successes, invokes a suite of distinct models, degrees of freedom and assumptions of as yet unknown quantitative consequence. We pose a set of important open questions, and suggest additional measurements, at least some of which should be addressed in order to establish a compelling basis to conclude definitively that thermalized, deconfined quark–gluon matter has been produced at RHIC.
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