We review a perturbative approach to deal with Lagrangians with higher or infinite order time derivatives. It enables us to construct a consistent Poisson structure and Hamiltonian with only first ...time derivatives order by order in coupling. We show that, to the lowest order, the Hamiltonian is bounded from below whenever the potential is. We consider spacetime noncommutative field theory as an example.
We assessed the independent relationship between age and the quality of medical care provided to patients presenting to the emergency department (ED) with acute myocardial infarction.
We conducted a ...2-year retrospective cohort study of 2,216 acute myocardial infarction patients presenting urgently to 5 EDs in Colorado and California from July 1, 2000, through June 30, 2002. Data on patient characteristics, clinical presentation, and ED processes of care were obtained from the ED record and ECG review. Patients were divided into 6 groups based on their age at the time of their ED visit: younger than 50 years, 50 to 59 years, 60 to 69 years, 70 to 79 years, 80 to 89 years, and 90 years or older. Hierarchic multivariable regression was used to assess the independent association between age and the provision of aspirin, β-blockers, and reperfusion therapy (fibrinolytic agent or percutaneous coronary intervention) in the ED to eligible acute myocardial infarction patients.
Of ideal candidates for treatment in the ED, 1,639 (80.5%) of 2,036 received aspirin, 552 (60.3%) of 916 received β-blockers, and 358 (77.8%) of 460 received acute reperfusion therapy. After adjustment for demographic, medical history, and clinical factors, older patients were less likely to receive aspirin (odds ratio OR 0.85, 95% confidence interval CI 0.77 to 0.93), β-blockers (OR 0.79, 95% CI 0.71 to 0.88), and reperfusion therapy (OR 0.30, 95% CI 0.18 to 0.52).
Older patients presenting to the ED with acute myocardial infarction receive lower-quality medical care than younger patients. Further investigation to identify the reasons for this disparity and to intervene to reduce gaps in care quality will likely lead to improved outcomes for older acute myocardial infarction patients.
In this Letter we show that the worldline reparametrization for particles with higher derivative interactions appears as a higher-dimensional symmetry, which is generated by a truncated Virasoro ...algebra. We also argue that for generic nonlocal particle theories the fields on the worldline may be promoted to those living on a two-dimensional worldsheet, and the reparametrization symmetry becomes locally the same as the conformal symmetry.
Following the recent work of Connes, Douglas and Schwarz, we study the M(atrix) model compactified on a torus with a background of the three-form field. This model is given by a super Yang-Mills ...theory on a quantum torus. To consider twisted gauge field configurations, we construct twisted
U(
n) bundles on the quantum torus as a deformation of its classical counterpart. By properly taking into account membranes winding around the light-cone direction, we derive from the M(atrix) model the BPS spectrum which respects the full
SL(2,
Z)×SL(2,
Z)
U-duality in M theory.
The goal of this study was to determine if cardiology subspecialty involvement improves the attainment of recommended low-density lipoprotein (LDL) cholesterol and blood pressure (BP) targets in ...coronary artery disease (CAD) patients.
The impact of physician specialty on secondary prevention measures for CAD in ambulatory care is unknown.
This was a retrospective cohort study of 13,995 patients with CAD seen at eight ambulatory care Veteran Affairs facilities from 1998 to 2000. Patients with cardiology involvement were defined as those seen in cardiology clinic in addition to primary care. The main outcomes of interest were LDL cholesterol ≤100 mg/dl and BP ≤130/85 mm Hg. Multivariable hierarchical regression analyses were used to determine the independent association of cardiology involvement with improved LDL cholesterol and BP control.
Overall, 3,771 (27.0%) patients had cardiology involvement. A higher proportion of patients with cardiology involvement achieved LDL cholesterol (55.6% vs. 45.6%; p < 0.01) and BP (45.3% vs. 35.9%; p < 0.01) goals. In multivariable hierarchical regression analysis, cardiology involvement was independently associated with better LDL cholesterol (odds ratio OR, 1.59; 95% confidence interval CI, 1.40 to 1.82) and BP (OR, 1.52; 95% CI, 1.32 to 1.77) control. The benefit of cardiology involvement was consistent across a range of LDL and BP targets, in analysis of LDL and BP as continuous outcomes, and among subgroups of high-risk patients, including diabetic patients, the elderly, and those with prior revascularization.
Cardiology involvement is associated with better LDL cholesterol and BP control among CAD patients. However, significant room for improvement in secondary prevention measures remains, irrespective of physician specialty.
The ability to change illumination is a crucial factor in image-based modeling and rendering. Image-based relighting offers such capability. However, the tradeoff is the enormous increase of storage ...requirement. In this paper, we propose a compression scheme that effectively reduces the data volume while maintaining the real-time relighting capability. The proposed method is based on principal component analysis (PCA). A block-wise PCA is used to practically process the huge input data. The output of PCA is a set of eigenimages and the corresponding relighting coefficients. By dropping those low-energy eigenimages, the data size is drastically reduced. To further compress the data, eigenimages left are compressed using transform coding and quantization while the relighting coefficients are compressed using uniform quantization. We also suggest the suitable target bit rate for each phase of the compression method in order to preserve the visual quality. Finally, we propose a real-time engine that relights images from the compressed data.
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