From Malthus to Modern Growth: Can Epidemics Explain the Three Regimes?

These are the stylized facts of long-run economic and demographic development, as described by Galor and Weil (AER 1999, 2000): Under an initial Malthusian Regime the growth rates of population and per-capita income are both low. Then follows a Post-Malthusian Regime, with higher growth rates of both population and per-capita income. Finally, the economy transits into a Modern Growth Regime, with falling population growth rates, but accelerated growth rates of per-capita inocme. This paper models the transition through all these three regimes endogenously. The model also captures the empirical regularity of a simultaneous fall in the level and the volatility of death rates, and the fact that death rates fell before birth rates. Throughout time, we let epidemic shocks hit the economy at a constant rate. However, with rising human capital the impact of these shocks is mitigated. For many generations the economy is stuck in a Malthusian Regime with volatile and high death rates. Sooner or later it experiences a phase of relatively mild epidemics. Mortality declines, enabling population and human capital to simultaneously start growing: a Post-Malthusian Regime. Once human capital growth has taken off, epidemic shocks have smaller impact. Finally comes a stage where parents start having fewer children, and instead invest more in their education: a quality-quantity switch. This triggers faster growth in human capital. The economy enters the Modern Growth Regime.Malthus; population; income

A Nonparametric Examination of Capital-Skill Complementarity

This paper uses nonparametric kernel methods to construct observation-specific elasticities of substitution for a balanced panel of 73 developed and developing countries to examine the capital-skill complementarity hypothesis. The exercise shows some support for capital-skill complementarity, but the strength of the evidence depends upon the definition of skilled labor and the elasticity of substitution measure being used. The added flexibility of the nonparametric procedure is also able to uncover that the elasticities of substitution vary across countries, groups of countries and time periods.capital-skill complementarity, elasticity of substitution, nonparametric kernel, stochastic dominance

Identifying flaws in the security of critical sets in latin squares via triangulations

In this paper we answer a question in theoretical cryptography by reducing it to a seemingly unrelated geometrical problem. Drápal (1991) showed that a given partition of an equilateral triangle of side n into smaller, integer-sided equilateral triangles gives rise to, under certain conditions, a latin trade within the latin square based on the addition table for the integers (mod n). We apply this result in the study of flaws within certain theoretical cryptographic schemes based on critical sets in latin squares. We classify exactly where the flaws occur for an infinite family of critical sets. Using Drápal's result, this classification is achieved via a study of the existence of triangulations of convex regions that contain prescribed triangles

State-of-the-art in aerodynamic shape optimisation methods

Aerodynamic optimisation has become an indispensable component for any aerodynamic design over the past 60 years, with applications to aircraft, cars, trains, bridges, wind turbines, internal pipe flows, and cavities, among others, and is thus relevant in many facets of technology. With advancements in computational power, automated design optimisation procedures have become more competent, however, there is an ambiguity and bias throughout the literature with regards to relative performance of optimisation architectures and employed algorithms. This paper provides a well-balanced critical review of the dominant optimisation approaches that have been integrated with aerodynamic theory for the purpose of shape optimisation. A total of 229 papers, published in more than 120 journals and conference proceedings, have been classified into 6 different optimisation algorithm approaches. The material cited includes some of the most well-established authors and publications in the field of aerodynamic optimisation. This paper aims to eliminate bias toward certain algorithms by analysing the limitations, drawbacks, and the benefits of the most utilised optimisation approaches. This review provides comprehensive but straightforward insight for non-specialists and reference detailing the current state for specialist practitioners

Geography, Health Status, and Health Investments: An Analysis of Peru

The study examines the influence of natural geography on human health in Peru, a country that has performed rather poorly, in the Latin American context, in terms of reducing its infant and maternal mortality rates. We measured natural geography through rainfall, temperature, altitude, longitude, and latitude. We also analyzed the effect that natural geography may have on the effectiveness of government health investments. We find evidence that geography has an important and independent influence on the infant mortality rate (IMR) and the child malnutrition rate (CMNR). As latitude and longitude increase (i. e. , as one moves towards the southwest) the IMR drops. Also, higher levels of rainfall (as in the Jungle region), and higher latitudes increase the CMNR. Lower temperatures, such as those observed in the Mountain region, seem to cause higher rates of child malnutrition. Geography also appears to affect the effectiveness of government health care investments. As latitude increases towards the south, thereby reducing the IMR, health centers and posts see their effectiveness reduced. Likewise, as longitude increases towards the west, thus helping to reduce the IMR, government health centers and posts become less effective in curtailing infant mortality. These results point to a decreasing marginal productivity of government health care spending. Several variables other than geography also affect health status. For example, we find that an increase in the illiteracy rate from 10 percent to 50 percent would bring about an increase in the IMR from 40 to 75 deaths per 1,000 live births. Female illiteracy has an important influence on the IMR as well, with higher levels of illiteracy being associated with a higher IMR. A policy of increasing general and female education through public spending thus appears to be an effective way of improving infant and child health. The government of Peru has invested heavily in ambulatory facilities in areas of high IMR. These new investments may have had a positive impact on child health. However, whatever this impact, so far it appears to be mild, and not enough to overcome the low health status that led to these new investments in the first place. While endogeneity problems have kept us from measuring the effectiveness of public investments in ambulatory care infrastructure, we find that the number of doctors working in public facilities has a positive influence on child health and nutritional status. We are able to show through simulations how new public resources devoted to new facilities and doctors could be allocated among the provinces to reduce regional inequality in health status. Finally, we find that natural geography exacerbates inequality in health status, as do existing regional differences in the availability of public services, such as potable water, sewerage, electricity, and in education. Public investments aimed at reducing or eliminating such differences would help to improve equity in health status.

Critical sets of full Latin squares

This thesis explores the properties of critical sets of the full n-Latin square and related combinatorial structures including full designs, (m,n,2)-balanced Latin rectangles and n-Latin cubes. In Chapter 3 we study known results on designs and the analogies between critical sets of the full n-Latin square and minimal defining sets of the full designs. Next in Chapter 4 we fully classify the critical sets of the full (m,n,2)-balanced Latin square, by describing the precise structures of these critical sets from the smallest to the largest. Properties of different types of critical sets of the full n-Latin square are investigated in Chapter 5. We fully classify the structure of any saturated critical set of the full n-Latin square. We show in Theorem 5.8 that such a critical set has size exactly equal to n³ - 2n² - n. In Section 5.2 we give a construction which provides an upper bound for the size of the smallest critical set of the full n-Latin square. Similarly in Section 5.4, another construction gives a lower bound for the size of the largest non-saturated critical set. We conjecture that these bounds are best possible. Using the results from Chapter 5, we obtain spectrum results on critical sets of the full n-Latin square in Chapter 6. In particular, we show that a critical set of each size between (n - 1)³ + 1 and n(n - 1)² + n - 2 exists. In Chapter 7, we turn our focus to the completability of partial k-Latin squares. The relationship between partial k-Latin squares and semi-k-Latin squares is used to show that any partial k-Latin square of order n with at most (n - 1) non-empty cells is completable. As Latin cubes generalize Latin squares, we attempt to generalize some of the results we have established on k-Latin squares so that they apply to k-Latin cubes. These results are presented in Chapter 8

On the intricacy of combinatorial construction problems

RESP-904