Current-induced cooling phenomenon in a two-dimensional electron gas under a magnetic field

We investigate the spatial distribution of temperature induced by a dc current in a two-dimensional electron gas (2DEG) subjected to a perpendicular magnetic field. We numerically calculate the distributions of the electrostatic potential phi and the temperature T in a 2DEG enclosed in a square area surrounded by insulated-adiabatic (top and bottom) and isopotential-isothermal (left and right) boundaries (with phi_{left} < phi_{right} and T_{left} =T_{right}), using a pair of nonlinear Poisson equations (for phi and T) that fully take into account thermoelectric and thermomagnetic phenomena, including the Hall, Nernst, Ettingshausen, and Righi-Leduc effects. We find that, in the vicinity of the left-bottom corner, the temperature becomes lower than the fixed boundary temperature, contrary to the naive expectation that the temperature is raised by the prevalent Joule heating effect. The cooling is attributed to the Ettingshausen effect at the bottom adiabatic boundary, which pumps up the heat away from the bottom boundary. In order to keep the adiabatic condition, downward temperature gradient, hence the cooled area, is developed near the boundary, with the resulting thermal diffusion compensating the upward heat current due to the Ettingshausen effect.Comment: 25 pages, 7 figure

Impact of candesartan on nonfatal myocardial infarction and cardiovascular death in patients with heart failure

CONTEXT: Angiotensin-converting enzyme (ACE) inhibitors reduce the risk of myocardial infarction (MI), but it is not known whether angiotensin receptor blockers have the same effect. OBJECTIVE: To assess the impact of the angiotensin receptor blocker candesartan on MI and other coronary events in patients with heart failure. DESIGN, SETTING, AND PARTICIPANTS: The Candesartan in Heart Failure: Assessment of Reduction in Mortality and Morbidity (CHARM) program, a randomized, placebo-controlled study enrolling patients (mean age, 66 [SD, 11] years) with New York Heart Association class II to IV symptoms who were randomly allocated to receive candesartan (target dose, 32 mg once daily) or matching placebo given in addition to optimal therapy for heart failure. Patients were enrolled from March 1999 through March 2001. Of 7599 patients allocated, 4004 (53%) had experienced a previous MI, and 1808 (24%) currently had angina. At baseline, 3125 (41%) were receiving an ACE inhibitor; 4203 (55%), a beta-blocker; 3153 (42%), a lipid-lowering drug; 4246 (56%), aspirin; and 6286 (83%), a diuretic. MAIN OUTCOME MEASURE: The primary outcome of the present analysis was the composite of cardiovascular death or nonfatal MI in patients with heart failure receiving candesartan or placebo. RESULTS: During the median follow-up of 37.7 months, the primary outcome of cardiovascular death or nonfatal MI was significantly reduced in the candesartan group (775 patients [20.4%]) vs the placebo group (868 [22.9%]) (hazard ratio [HR], 0.87; 95% confidence interval [CI], 0.79-0.96; P = .004; number needed to treat [NNT], 40). Nonfatal MI alone was also significantly reduced in the candesartan group (116 [3.1%]) vs the placebo group (148 [3.9%]) (HR, 0.77; 95% CI, 0.60-0.98; P = .03; NNT, 118). The secondary outcome of fatal MI, sudden death, or nonfatal MI was significantly reduced with candesartan (459 [12.1%]) vs placebo (522 [13.8%]) (HR, 0.86; 95% CI, 0.75-0.97; P = .02; NNT, 59). Risk reductions in cardiovascular death or nonfatal MI were similar across predetermined subgroups and the component CHARM trials. There was no impact on hospitalizations for unstable angina or coronary revascularization procedures with candesartan. CONCLUSION: In patients with heart failure, candesartan significantly reduces the risk of the composite outcome of cardiovascular death or nonfatal MI

Chinese demand for Australian wheat : application of market share models

Changes in the market shares of Australian wheat in the Chinese import market over the period 1960/61 - 1989/90 were analysed using three modelling procedures. The empirical results indicate that, in addtion the relative price changes (P), retail availability index (R), which measures the total production in Australia relative to the average production in other wheat exporting countries, is important in determining market share changes. Market share is reported in all the models to be extremely price elastic both in the short and long run. Market share elasticity with respect to R is found to be inelastic in the short run but elastic in the long run

A drunk and her dog: a spurious relation? Cointegration tests as instruments to detect spurious correlations between integrated time series

Spurious correlation, Spurious regression, Cointegration, Multivariate time series analysis, Psychological process research, Longitudinal analysis, Stationarity, Monte Carlo experiments,