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The Kaldor model describes the dynamics of economic growth over time. Many works showed that a large variety of qualitative dynamics can be produced depending on the economic assumptions. This work provides conditions to mark boundaries during boom and bust cycles, investigating how saving behaviors of workers and shareholders and elasticity of substitution between capital and labor influence the growth dynamics of non‐developed, developing and developed countries considering general and specific technologies of production. The results obtained can be used by policy‐makers to increase the lower level an economy can reach during boom and bust periods and reduce fluctuations. [ABSTRACT FROM AUTHOR]

In this paper we analyze the dynamics shown by the neoclassical one-sector growth model with differential savings as in Bohm and Kaas [J. Econom. Dynam. Control, 24 (2000), pp. 965--980] while assuming a sigmoidal production function as in [V. Capasso, R. Engbers, and D. La Torre, Nonlinear Anal., 11 (2010), pp. 3858--3876] and the labor force dynamics described by the Beverton--Holt equation (see [R. J. H. Beverton and S. J. Holt, Fishery Invest., 19 (1957), pp. 1--533]). We prove that complex features are exhibited, related both to the structure of the coexisting attractors (which can be periodic or chaotic) and to their basins (which can be simple or nonconnected). In particular we show that complexity emerges if the elasticity of substitution between production factors is low enough and shareholders save more than workers, confirming the results obtained with concave production functions. Anyway, in contrast to previous studies, the use of the S-shaped production function implies the existence of a poverty trap: by performing a global analysis we study the properties of the regions generating trajectories converging to it. [ABSTRACT FROM AUTHOR]

Background: The separation of patients with suspected or known coronary artery disease into low- and high-risk subgroups by means of noninvasive testing is highly relevant in the selection of patients who require further diagnostic or therapeutic investigation. We evaluated whether exercise electrocardiographic variables during exercise testing might be a means of predicting the severity of myocardial ischemia as assessed with myocardial scintigraphy.Methods and Results: We retrospectively reviewed 816 consecutive patients (mean age, 57+/-10 years) who underwent exercise technetium-99m tetrofosmin single photon emission computed tomography (SPECT) for the assessment of suspected or known coronary artery disease. Eight independent significant predictors of the extent and severity of reversible perfusion defects (ischemic perfusion score), which when integrated in a diagnostic algorithm satisfactorily discriminated patients with no reversible perfusion defects (sensitivity, 75%; specificity, 80%) and patients with severe impaired myocardial perfusion (> or =11 ischemic perfusion score; sensitivity, 77%; specificity, 82%), were identified by means of stepwise discriminant analysis. However, patients with mildly to moderately impaired myocardial perfusion (> or =21 but <11 ischemic perfusion score) were poorly discriminated (sensitivity, 50%; specificity, 78%). The set of variables that were significant (P<.0001) for prediction included sex, myocardial infarction, exercise angina, the maximal amount of ST segment depression, rate-pressure product threshold criteria, slope of ST segment depression, ST/heart rate index, and peak exercise heart rate.Conclusions: The results of the use of clinical and electrocardiographic exercise variables satisfactorily agrees with the results from scintigraphy only for patients with no reversible perfusion defects and with severely impaired myocardial perfusion. However, it fails as an approach with universal applicability. [ABSTRACT FROM AUTHOR]

Background: Technetium 99m-labeled myocardial agents have been proposed as an alternative to thallium 201. The aim of this study was to assess retrospectively the accuracy of exercise myocardial 99mTc-tetrofosmin scintigraphy with tomographic imaging (SPECT) in a large group population in the evaluation of coronary artery disease. Furthermore we evaluated the relation between the severity of scintigraphic impaired myocardial perfusion and the angiographic coronary artery stenoses in patients without myocardial infarction and with stenosis localized exclusively in the proximal segment of the 3 main coronary arteries.Methods and Results: The study group consisted of 235 consecutive patients, 204 (87%) of whom were men, with a mean age of 57+/-10 years, and with suspected or known coronary artery disease, who underwent 99mTc-tetrofosmin SPECT and coronary angiography. Furthermore, 61 patients in a low-likelihood group for coronary artery disease were also studied. Significant disease was defined by > or = 50% luminal coronary artery stenosis in > or = 1 native coronary artery or major branch or in a saphenous vein graft or arterial mammary graft. The overall sensitivity was 95%, specificity was 76%, and predictive accuracy was 95%. The normalcy rate for the low-likelihood group was 93%. Sensitivity was 71% for the left anterior descending artery, 61% for the left circumflex artery, and 73% for the right coronary artery. Specificity was 94% for the left anterior descending artery, 96% for the left circumflex artery, and 91% for the right coronary artery. Predictive accuracy was 79% for the left anterior descending artery, 78% for the left circumflex artery, and 81 % for the right coronary artery. In patients without myocardial infarction linear regression analysis between scintigraphy and angiography showed a significant correlation in patients with severe proximal coronary artery stenosis (r = 0.53, P < .002), but not in those with moderate proximal stenosis (r = 0.31, P = NS).Conclusions: This study shows that 99mTc-tetrofosmin SPECT is accurate in the detection of coronary artery disease. The relation of the severity of scintigraphic impaired myocardial perfusion and angiographic coronary artery stenosis, however, may differ significantly in patients with proximal stenosis of different severity. [ABSTRACT FROM AUTHOR]