938,661 research outputs found

    Universal features in the growth dynamics of complex organizations

    Full text link
    We analyze the fluctuations in the gross domestic product (GDP) of 152 countries for the period 1950--1992. We find that (i) the distribution of annual growth rates for countries of a given GDP decays with ``fatter'' tails than for a Gaussian, and (ii) the width of the distribution scales as a power law of GDP with a scaling exponent β≈0.15\beta \approx 0.15. Both findings are in surprising agreement with results on firm growth. These results are consistent with the hypothesis that the evolution of organizations with complex structure is governed by similar growth mechanisms.Comment: 4 pages, 7 ps figures, using Latex2e with epsf rotate and multicol style files. Submitted to PR

    Distribution Dynamics of Dietary Energy Supply in the World

    Get PDF
    This paper investigates the law of motion for the cross-section distribution of dietary energy supply (DES) in the world. This has been pursued using the distribution approach and a panel of 152 countries for the period 1961-2001. According to the empirical results, persistence in caloric intakes dominates in the short-run. With time, however, upwards mobility gains momentum and the world is moving towards a long-run distribution, which is strongly skewed to the left. The estimated expected first passage times from extreme under-supply to higher intake levels are consistent with speculations that most of the developing countries will attain the 3000 kcal per person per day level by the year 2030.caloric intakes, mobility, World, Food Consumption/Nutrition/Food Safety, C10, D12,

    Constraint or choice? Disentangling fertility determinants by switching regressions

    Get PDF
    In 1953, many poor countries had not yet approached the demographic transition. Accordingly, income generally had a positive impact on fertility in poor countries, while it has a negative impact today. Easterlin´s supply-demand framework offers an explanation for this nonlinearity by attributing the positive relationship to Malthusian (or "supply") factors and the negative relationship to "demand" factors. This paper estimates Easterlin´s supply-demand framework by switching regressions in a panel data set of 152 countries from 1953 to 1998. The technique allows identifying several factors affecting the Malthusian constraint and the demand for children, such as income, the source of income, urbanization, religion and the medical environment. It is found that a combination of higher GDP per capita, a decrease in the infant death rate and an increase in education explain a substantial part of the reversal of the relationship between income and net fertility over the sample period.demographic transition, fertility determinants, income fertility relationship, supply-demand framework, switching regression

    Reactions of differential varieties to the rice gall midge \u3ci\u3eOrseolia oryzae\u3c/i\u3e in Asia. Report of an international collaborative research project.

    Get PDF
    Varieties and breeding lines known to be resistant to the gall midge in some areas of Asia were tested in China, India, Indonesia, Sri Lanka, and Thailand from 1977- 1980. Differential reactions were evident, indicating variations in the virulence of gall midge populations in the various countries. Eswarakora derivatives were resistant in Thailand but susceptible in Indonesia; Leuang 152 was resistant in Indonesia but susceptible in Thailand. In India, Eswarakora derivatives were susceptible in Orissa but resistant in Andhra Pradesh. The Leuang 152 and Ob 677 groups were resistant at all test sites except in Thailand and Bihar, India

    How socially sustainable multinational banks promote financial inclusion in developing countries

    Get PDF
    This paper investigates the impact of multinational banks (MNBs) implementing socially sustainable practices on financial inclusion in developing countries. We argue that the specific characteristics of the MNBs, when combined with socially sustainable practices, contribute to building trust and reducing risks in developing countries where they operate. This positive externality causes improvements for the underprivileged in three dimensions of financial inclusion: their demand for bank accounts, their propensity to save, and their access to credit. A sample of 152 multinational banks in 32 developing countries and 37,952 individuals proves the positive effect of sustainable practices

    Relative efforts of countries to conserve world’s megafauna

    Get PDF
    Surprisingly little attention has been paid to variation among countries in contributions to conservation. As a first step, we developed a Megafauna Conservation Index (MCI) that assesses the spatial, ecological and financial contributions of 152 nations towards conservation of the world’s terrestrial megafauna. We chose megafauna because they are particularly valuable in economic, ecological and societal terms, and are challenging and expensive to conserve. We categorised these 152 countries as being above- or below-average performers based on whether their contribution to megafauna conservation was higher or lower than the global mean; ‘major’ performers or underperformers were those whose contribution exceeded 1 SD over or under the mean, respectively. Ninety percent of countries in North/Central America and 70% of countries in Africa were classified as major or above-average performers, while approximately one-quarter of countries in Asia (25%) and Europe (21%) were identified as major underperformers. We present our index to emphasize the need for measuring conservation performance, to help nations identify how best they could improve their efforts, and to present a starting point for the development of more robust and inclusive measures (noting how the IUCN Red List evolved over time). Our analysis points to three approaches that countries could adopt to improve their contribution to global megafauna conservation, depending on their circumstances: 1) upgrading or expanding their domestic protected area networks, with a particular emphasis on conserving large carnivore and herbivore habitat, 2) increase funding for conservation at home or abroad, or 3) ‘rewilding’ their landscapes. Once revised and perfected, we recommend publishing regular conservation rankings in the popular media to recognise major-performers, foster healthy pride and competition among nations, and identify ways for governments to improve their performance

    The Hetu'u Global Network: Measuring the Distance to the Sun Using the June 5th/6th Transit of Venus

    Full text link
    In the spirit of historic astronomical endeavors, we invited school groups across the globe to collaborate in a solar distance measurement using the rare June 5/6th transit of Venus. In total, we recruited 19 school groups spread over 6 continents and 10 countries to participate in our Hetu'u Global Network. Applying the methods of French astronomer Joseph-Nicolas Delisle, we used individual second and third Venus-Sun contact times to calculate the distance to the Sun. Ten of the sites in our network had amiable weather; 8 of which measured second contact and 5 of which measured third contact leading to consistent solar distance measurements of 152+/-30 million km and 163+/-30 million km respectively. The distance to the Sun at the time of the transit was 152.25 million km; therefore, our measurements are also consistent within 1sigma of the known value. The goal of our international school group network was to inspire the next generation of scientists using the excitement and accessibility of a rare astronomical event. In the process, we connected hundreds of participating students representing a diverse, multi-cultural group with differing political, economic, and racial backgrounds.Comment: 19 pages; 7 Figures; 1 Table; Accepted for publication in Astronomy Education Review (AER) For more information see http://www.das.uchile.cl/~drodrigu/easter/index_en.htm

    Modeling the effect of lockdown timing as a COVID‑19 control measure in countries with differing social contacts

    Get PDF
    The application, timing, and duration of lockdown strategies during a pandemic remain poorly quantified with regards to expected public health outcomes. Previous projection models have reached conflicting conclusions about the effect of complete lockdowns on COVID-19 outcomes. We developed a stochastic continuous-time Markov chain (CTMC) model with eight states including the environment (SEAMHQRD-V), and derived a formula for the basic reproduction number, R0, for that model. Applying the R 0 formula as a function in previously-published social contact matrices from 152 countries, we produced the distribution and four categories of possible R 0 for the 152 countries and chose one country from each quarter as a representative for four social contact categories (Canada, China, Mexico, and Niger). The model was then used to predict the effects of lockdown timing in those four categories through the representative countries. The analysis for the effect of a lockdown was performed without the influence of the other control measures, like social distancing and mask wearing, to quantify its absolute effect. Hypothetical lockdown timing was shown to be the critical parameter in ameliorating pandemic peak incidence. More importantly, we found that well-timed lockdowns can split the peak of hospitalizations into two smaller distant peaks while extending the overall pandemic duration. The timing of lockdowns reveals that a “tunneling” effect on incidence can be achieved to bypass the peak and prevent pandemic caseloads from exceeding hospital capacity
    • …
    corecore