INCOME DISPARITIES, ECONOMIC GROWTH, AND DEVELOPMENT AS A THRESHOLD

Galor and Moav (2004) argue that in the early stages of development, physical capital accumulation is the primary source of economic growth. Thus, inequality enhances growth by channeling resources towards individuals whose marginal propensity to save is higher. In later stages of development, physical capital is replaced by human capital as the engine of growth. Accordingly, equality alleviates the adverse effects of credit constraints on human capital accumulation and prompts the growth process. This paper attempts to test empirically the finding that the impact of income inequality on economic growth depends on the development stage. A threshold estimation technique, developed by Hansen (1999), is utilized for a panel of 70 countries for the period between 1970 and 1999. The estimation suggests that there is a statistically significant threshold income per capita, below which the coefficient on the relationship between inequality and growth is significantly negative and above which the estimate is positive, but not statistically significant.Income Inequality, Economic Growth

First Principles Calculation of Field Emission from Nanostructures using Time-Dependent Density Functional Theory: a Simplified Approach

We introduce a new simplified method for computing the electron field emission current in short carbon nanotubes using ab-initio computation in periodic simulation cells. We computed the evolution of the wave functions using Time-Dependent Density Functional Theory, where we have utilized the Crank-Nicholson propagator. We found that in pristine carbon nanotubes, the emitted charge tends to emerge mostly from electrons that are concentrated at the nanotube tip region. The charge beam concentrates into specific channel structures, showing the utility of carbon nanotubes in precision emission applications.Comment: Submitted to Physica

An Easy Combinatorial Algorithm for the Construction of Sextet Polynomials of Cata-Condensed Benzenoid Hydrocarbons

Two types oif i>mning techniques for cer.tain trees are described and utilized into an easy combinatorial a1gorithm for the f:?YStematic construction o.f sextet polynomials of catacon.densed benzenoid hydrocarbons of large sizes. The a1gori.thm oiffers an ailte!l\u27na.tive to ex~sting methods !or the enumeration of Kekule structures which is not restricted to non-branched systems

Non-Invasive Imaging for the Assessment of Cardiac Dose and Function Following Focused External Beam Irradiation

Technological advances in imaging and radiotherapy have led to significant improvement in the survival rate of breast cancer patients. However, a larger proportion of patients are now exhibiting the less understood, latent effects of incidental cardiac irradiation that occurs during left-sided breast radiotherapy. Here, we examine the utility of four-dimensional computed tomography (4D-CT) for the accurate assessment of cardiac dose; and a hybrid positron emission tomography (PET) magnetic resonance imaging (MRI) system to longitudinally study radiation-induced cardiac effects in a canine model. Using 4D-CT and deformable dose accumulation, we assessed the variation caused by breathing motion in the estimated dose to the heart, left-ventricle, and left anterior descending artery (LAD) of left-sided breast cancer patients. The LAD showed substantial variation in dose due to breathing. In light of this, we suggest the use of 4D-CT and dose accumulation for future clinical studies looking at the relationship between LAD dose and cardiac toxicity. Although symptoms of cardiac dysfunction may not manifest clinically for 10-15 years post radiation, PET-MRI can potentially identify earlier changes in cardiac inflammation and perfusion that are typically asymptomatic. Using PET-MRI, the progression of radiation-induced cardiac toxicity was assessed in a large animal model. Five canines were imaged using 13N-ammonia and 18F-fluorodeoxyglucose (FDG) PET-MRI to assess changes in myocardial perfusion and inflammation, respectively. All subjects were imaged at baseline, 1 week, 4 weeks, 3 months, 6 months, and 12 months after focused cardiac irradiation. To the best of our knowledge PET has not been previously used to assess cardiac perfusion following irradiation. The delivered dose to the heart, left ventricle, LAD, and left circumflex artery were comparable to what has been observed during breast radiotherapy. Relative to baseline, a transient increase in myocardial perfusion was observed followed by a gradual return to baseline. However, a persistent increase in FDG uptake was observed throughout the entire left ventricle, including both irradiated and less-irradiated portions of the heart. In light of these findings, we suggest the use of this imaging approach for future human studies to assess mitigation strategies aimed at minimizing cardiac exposure and long-term toxicity subsequent to left-sided breast irradiation

An Easy Combinatorial Algorithm for the Construction of Sextet Polynomials of Cata-Condensed Benzenoid Hydrocarbons

Two types oif i>mning techniques for cer.tain trees are described and utilized into an easy combinatorial a1gorithm for the f:?YStematic construction o.f sextet polynomials of catacon.densed benzenoid hydrocarbons of large sizes. The a1gori.thm oiffers an ailte!l\u27na.tive to ex~sting methods !or the enumeration of Kekule structures which is not restricted to non-branched systems

Molecular Topology and Molecular Properties I. »Sequence« Labels of Cata-Condensed Benzenoid Hydrocarbons Containing up to Five Rings

An algorithm ds described for the systematic numbering o,f benz,enoid hydrocarbons. The sum of decimal contributions of all vertices (carbon atoms) in th.e molecular graph is called the hydrocarbon label, L. These labels, which are based on pua:ely structural elements order a set o{ isomeric benzenoid hydrocarbons according to their properties including resonance and total pi-energies, ionization potent~als, heats of atomization, energies of lowest vacant and lo·west filled molecular orbitals and polarographic haLf-wave reduction potentials. Such hydrocarbon labels might easily be computed without resort to a computer