The physics at the event horizon resembles the behavior of waves in moving media. Horizons are formed where the local speed of the medium exceeds the wave velocity. We used ultrashort pulses in ...microstructured optical fibers to demonstrate the formation of an artificial event horizon in optics. We observed a classical optical effect: the blue-shifting of light at a white-hole horizon. We also showed by theoretical calculations that such a system is capable of probing the quantum effects of horizons, in particular Hawking radiation.
The management of heart failure is characterized by high rates of hospital admission as well as rehospitalization after inpatient treatment of this disorder, whereas skillful medical care may reduce ...the risk of hospital admission. The purpose of this study was to examine the relation between income (as a measure of socioeconomic status) and the frequency of hospital readmission among a large and diverse group of persons treated for heart failure. We analyzed administrative discharge data from 236 nonfederal acute-care hospitals in New York State, involving 41,776 African-American or Caucasian hospital survivors with International Classification of Diseases, Ninth Revision, Clinical Modification codes for heart failure in the principal diagnosis position between January 1 and December 31, 1995. Household income was derived from postal ZIP codes and census data. We found that patients residing in lower income neighborhoods were more often women or African-Americans, had more comorbid illness, had higher use of Medicaid insurance, and were more often admitted to rural hospitals. There was a stepwise decrease in the crude frequency of readmission from the lowest quartile of income (23.2%) to the highest (20.0%) (p <0.0001 for Mantel-Haenszel chi-square test for trend across all quartiles; p <0.0001 for comparison between quartiles 1 and 4). After adjustment for baseline differences and process of care, income remained a significant predictor, with an increase in the risk of readmission noted in association with lower levels of income (adjusted odds ratio for quartile 1:4 comparison, 1.18; 95% confidence interval, 1.10 to 1.26, p <0.0001). We conclude that lower income patients hospitalized for treatment of heart failure in New York differ from higher income patients in important clinical and demographic comparisons. Even after adjustment for these fundamental differences and other potential confounding factors, lower income is a positive predictor of readmission risk.
OBJECTIVES
The purpose of this study was to develop a convenient and inexpensive method for identifying an individual’s risk for hospital readmission for congestive heart failure (CHF) using ...information derived exclusively from administrative data sources and available at the time of an index hospital discharge.
BACKGROUND
Rates of readmission are high after hospitalization for CHF. The significant determinants of rehospitalization are debated.
METHODS
Administrative information on all 1995 hospital discharges in New York State which were assigned International Classification of Diseases–9–Clinical Modification codes indicative of CHF in the principal diagnosis position were obtained. The following were compared among hospital survivors who did and did not experience readmission: demographics, comorbid illness, hospital type and location, processes of care, length of stay and hospital charges.
RESULTS
A total of 42,731 black or white patients were identified. The subgroup of 9,112 patients (21.3%) who were readmitted were distinguished by a greater proportion of blacks, a higher prevalence of Medicare and Medicaid insurance, more comorbid illnesses and the use of telemetry monitoring during their index hospitalization. Patients treated at rural hospitals, those discharged to skilled nursing facilities and those having echocardiograms or cardiac catheterization were less likely to be readmitted. Using multiple regression methods, a simple methodology was devised that segregated patients into low, intermediate and high risk for readmission.
CONCLUSIONS
Patient characteristics, hospital features, processes of care and clinical outcomes may be used to estimate the risk of hospital readmission for CHF. However, some of the variation in rehospitalization risk remains unexplained and may be the result of discretionary behavior by physicians and patients.
The case for artificial black holes Leonhardt, Ulf; Philbin, Thomas G
Philosophical transactions of the Royal Society of London. Series A: Mathematical, physical, and engineering sciences,
08/2008, Letnik:
366, Številka:
1877
Journal Article
Recenzirano
The event horizon is predicted to generate particles from the quantum vacuum, an effect that bridges three areas of physics-general relativity, quantum mechanics and thermodynamics. The quantum ...radiation of real black holes is too feeble to be detectable, but black-hole analogues may probe several aspects of quantum black holes. In this paper, we explain in simple terms some of the motivations behind the study of artificial black holes.
Race and gender are important determinants of certain clinical outcomes in cardiovascular disease. To examine the influence of race and gender on care process, resource use, and hospital-based case ...outcomes for patients with congestive heart failure (CHF), we obtained administrative records on all 1995 New York State hospital discharges assigned ICD-9-CM codes indicative of this diagnosis. The following were compared among black and white women and men: demographics, comorbid illness, care processes, length of stay (LOS), hospital charges, mortality rate, and CHF readmission rate. We identified 45,894 patients (black women, 4,750; black men, 3,370; white women, 21,165; white men, 16,609). Blacks underwent noninvasive cardiac procedures more often than whites; procedure and specialty use rates were lower among women than among men. After adjusting for other patient characteristics and hospital type and location, we found race to be an important determinant of LOS (black, 10.4 days; white, 9.3 days; p = 0.0001), hospital charges (black, $13,711; white, $11,074; p = 0.0001), mortality (black-to-white odds ratio = 0.832; p = 0.003), and readmission (black-to-white odds ratio = 1.301; p = 0.0001). Gender was an important determinant of LOS (women, 9.8 days; men, 9.2 days; p = 0.0001), hospital charges (women, $11,690; men, $11,348; p = 0.02), and mortality (women-to-men odds ratio = 0.878; p = 0.0008). We conclude that race and gender influence care process and hospital-based case outcomes for patients with CHF.
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