938,661 research outputs found
Universal features in the growth dynamics of complex organizations
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 . 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
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
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.
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
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 worldâs megafauna
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 worldâs 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; âmajorâ 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) ârewildingâ 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
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 COVIDâ19 control measure in countries with differing social contacts
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 âtunnelingâ effect on incidence can be achieved to bypass the peak and prevent pandemic caseloads from exceeding hospital capacity
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