Parameterization of entrainment in a sheared convective boundary layer using a first-order jump model

Basic entrainment equations applicable to the sheared convective boundary layer (CBL) are derived by assuming an inversion layer with a finite depth, i.e., the first-order jump model. Large-eddy simulation data are used to determine the constants involved in the parameterizations of the entrainment equations. Based on the integrated turbulent kinetic energy budget from surface to the top of the CBL, the resulting entrainment heat flux normalized by surface heat flux is a function of the inversion layer depth, the velocity jumps across the inversion layer, the friction velocity, and the convection velocity. The developed first-order jump model is tested against large-eddy simulation data of two independent cases with different inversion strengths. In both cases, the model reproduces quite reasonably the evolution of the CBL height, virtual potential temperature, and velocity components in the mixed layer and in the inversion layer.Peer Reviewe

Flux-gradient relationship of water vapor in the surface layer obtained from CASES-99 experiment

The flux-gradient relationship of water vapor Fq was obtained from the Cooperative Atmosphere-Surface Exchange Study-1999 (CASES-99) field experiment, which was conducted on a flat and grassy field in the southeastern part of Kansas, USA, during October 1999. The CASES-99 data include turbulence measurements of wind, temperature, and vapor density along with their time-averaged values at various levels above the ground. Quality control of the data on the turbulent wind velocity, sonic temperature, and vapor density was performed prior to flux calculation. The turbulent sensible heat and latent heat fluxes were calculated using a 30-min window, and they were subsequently corrected and checked for the fulfillment of the steady state and for turbulence intensity. Weak fluxes and through-tower wind data were also excluded from the analysis. Vertical gradients of the mean values were obtained by differentiating functions fitted to the measured mean profiles. It was found that Φq is comparable to ΦT for weakly stable stratification and less than ΦT for strongly stable stratification. On the contrary, Φq was found to be larger than ΦT by approximately 20% for the neutral and unstable stratifications. The best fitting functions for water vapor are found to be Φq = 1.21(1 - 13.1z/L)^(-1/2) and Φq = 1.21(1 + 60.4z/L)^(1/3) for the unstable and stable stratifications, respectively

Six-Month Comparison of Coronary Endothelial Dysfunction Associated With Sirolimus-Eluting Stent Versus Paclitaxel-Eluting Stent

ObjectivesThis study was designed to investigate whether endothelial dysfunction is related to drug-eluting stent (DES) implantation at 6 months after stenting.BackgroundCurrent available DES could delay vessel healing and subsequently impair endothelial function.MethodsEndothelial function was estimated at 6-month follow-up in 75 patients (31 men, mean age 62.1 years) with a DES (39 sirolimus-eluting stents [SES], 36 paclitaxel-eluting stents [PES]), and 10 patients with a bare-metal stent (BMS) to the left anterior descending artery, by incremental acetylcholine (Ach) infusion (20 μg/min, 50 μg/min, 100 μg/min) and nitrate (200 μg/min) into the left coronary ostium. Vascular responses were quantitatively measured in arterial segments 5 mm proximal and distal to DES and compared with corresponding segments in the BMS group and midsegments in the left circumflex artery as a reference nonstented artery. All antianginal agents were withheld for at least 72 h before coronary angiography.ResultsGreater vasoconstriction to Ach was observed in both the SES and PES groups than in the BMS group or control segments of left circumflex artery. Vasoconstriction to Ach was more prominent in arterial segments distal to stents in both SES and PES groups compared with those in the BMS group (p < 0.001). The degree of vasoconstriction to Ach was similar between the SES and PES groups. Endothelium-independent vasodilatation to nitrate did not differ significantly between the study groups.ConclusionsAbnormal vasoconstriction to Ach was found in the SES and PES groups, especially in arterial segments distal to DES at 6 months after stenting, which suggests that DES has a potential long-term adverse effect on local coronary endothelial dysfunction

Recurrent Infective Endocarditis Associated With Pyogenic Spondylodiskitis

Infective endocarditis is a life-threatening condition caused by microbial infection of the heart's endocardial surface. This condition can also be associated with bacterial infections of other organs. We experienced an unusual case of recurrent infective endocarditis associated with pyogenic spondylodiskitis. A 70-year-old man presented with persistent fever and lower back pain visited our hospital. The patient had a past history of recurrent infective endocarditis. He was diagnosed with infective endocarditis again based on clinical symptoms and echocardiographic findings. Magnetic resonance imaging was used to evaluate lower back pain, which showed acute spondylodiskitis on L3 and L4 vertebrae. The patient completely recovered following four weeks of antibiotic therapy

Unilateral Pulmonary Edema: A Rare Initial Presentation of Cardiogenic Shock due to Acute Myocardial Infarction

Cardiogenic unilateral pulmonary edema (UPE) is a rare clinical entity that is often misdiagnosed at first. Most cases of cardiogenic UPE occur in the right upper lobe and are caused by severe mitral regurgitation (MR). We present an unusual case of right-sided UPE in a patient with cardiogenic shock due to acute myocardial infarction (AMI) without severe MR. The patient was successfully treated by percutaneous coronary intervention and medical therapy for heart failure. Follow-up chest Radiography showed complete resolution of the UPE. This case reminds us that AMI can present as UPE even in patients without severe MR or any preexisting pulmonary disease affecting the vasculature or parenchyma of the lung

Type 2 Myocardial Infarction Following Generalized Tonic-Clonic Seizure

Myocardial infarction is diagnosed when blood levels of biomarkers are increased in the clinical setting of acute myocardial ischemia. Among the biomarkers, troponin I is the preferred biomarker indicative of myocardial necrosis. It is tissue specific for the heart. Myocardial infarction is rarely reported following seizure. We report a case of elevated troponin I in a patient after an episode of generalized tonic-clonic seizure. The diagnosis was type 2 myocardial infarction

The Relationship Between Ambulatory Arterial Stiffness Index and Blood Pressure Variability in Hypertensive Patients

Background and Objectives: Ambulatory arterial stiffness index (AASI) is well known as a predictor of cardiovascular mortality in hypertensive patients. Mathematically, AASI reflect the standard deviation (SD) of blood pressure (BP) variation. AASI is measured higher levels in non-dipper than dipper. Thus, AASI has a possibility of not only reflecting arterial stiffness but also BP variability and/or autonomic nervous dysfunction. Subjects and Methods: Consecutive data from 418 untreated hypertensive patients were analyzed retrospectively. We examined the association between the 24-hour ambulatory BP monitoring (ABPM) parameters and AASI. Results: AASI had a simple correlation with age (R=0.189, p<0.001), relative wall thickness (RWT) (R=0.115, p=0.019), left ventricular mass index (LVMI) (R=0.192, p<0.001), average systolic BP (SBP) (R=0.232, p<0.001), average pulse pressure (PP) (R=0.363, p<0.001), SD of diastolic BP (DBP) (R=-0.352,p<0.001), SD of PP (R=0.330, p<0.001), SD of heart rate (HR) (R=-0.268, p<0.001), and nocturnal dipping (R=-0.137, p=0.005). In multiple linear regression analysis model including clinical parameters and 24 hour-ABPM parameters, independent predictors of AASI were SD of PP (beta=1.246, p<0.001), SD of DBP (beta=-1.067, p<0.001), SD of SBP (beta=-0.197, p<0.001), and non-dipper (beta=0.054, p=0.033). Conclusion: AASI is closely correlated with BP variability. The result of this study shows that AASI is not only a parameter for arterial stiffness, but also a parameter for BP variability

Influence of stratification and accelerations on boundary production of vertical motion

The influence of boundary layer pumping on an externally-forced synoptic-scale flow is examined. The results follow earlier theories of stratified incompressible Boussinesq flow. These theories state that the spin-down time scale and the penetration depth of the influence of boundary layer pumping are inversely proportional to the stratification and directly proportional to the horizontal length scale of the flow. However, the present development is performed in isentropic coordinates which allow estimates applicable to the atmosphere, and implicitly includes nonlinear influences due to tilting and vertical advection. This analysis indicates that boundary layer pumping could be important synoptically in the lower troposphere under conditions of significant surface stress and tropospheric stratification. The influence of stratification and accelerations on synoptic-scale, boundary layer production of vertical motion is examined for the case of oscillating boundary-layer flow driven by time-dependent, horizontally- periodic surface temperature perturbations. It is found that only very strong stratification can significantly reduce the boundary layer pumping through pressure adjustments within the boundary layer. As a step in understanding the complicated dynamics of the structure of accelerated stratified boundary layers, order-of-magnitude analyses of variables for each layer are examined. This structure depends on the relative magnitude of the non-dimensional forcing frequency and the product of the stratification parameter and Ekman number. Applications to both synoptic and diurnal atmospheric circulations are considered