A Test of Two Skew Models to Explain Cooperative Breeding

Synopsis Two competing models, reproductive skew and skew selection, have been constructed to explain the evolution of cooperation among unrelated breeders. Reproductive skew is a trade-off model that assumes breeding occurs under scarce resource conditions. One breeder gains units of fecundity at the expense of other breeders during aggressive, altruistic or tug-of-war transactions. After joining, the distribution of fecundity among breeders shifts from symmetrical to asymmetrical. In contrast, skew selection is a surplus model that assumes breeding occurs during a springtime glut. Skew selection assumes that fecundity among breeders is initially asymmetrical and that joining reduces the asymmetry of fecundity. This paper reports findings from a breeding experiment on the fire ant, Solenopsis invicta, which supported skew selection rather than reproductive skew. Joining was a win-win strategy for alpha and beta breeders; beta breeders gained within-group survival benefits; alpha breeders gained between-group survival benefits. In summary, skew selection extends Darwin’s theory of natural selection by revealing the self-interested core of cooperative breeding.      

Univariate Time-Series Analysis of Public Debt

Journal of Quantitative Economics - This paper presents a method whereby the properties of the undiscounted debt/GDP time-series for a country can be directly assessed in terms of components of...     

The role of permanent and transitory components in the fluctuations of Latin–American real exchange rates

Following the approach suggested by Engel and Kim (1999 Engel, C. 1999. Accounting for U.S. real exchange rates changes. Journal of Political Economy, 107: 507–38. [Crossref], [Web of Science ®] , [Google Scholar]), we estimate the permanent and transitory components of the real exchange rates in four Latin–American countries for the period 1957:01 to 2002:04. Results suggest that transitory component is the driving force of the real exchange rates in Argentina and Mexico. A principal role of the permanent component is observed in the real exchange rates of Brazil and Chile. Estimates probabilities of the high-variance regime allow to identify the principal events happened in these countries. This information is closely related to nominal shocks and therefore, it explains the significant role of this component in these countries.     

Hotel employees’ expectations of QWL: A qualitative study

The hospitality industry needs to provide a good quality of work life (QWL) in order to attract and retain employees. There is yet to be a study that defines the ‘expected dimensions of QWL’ by the potential and present hotel employees. QWL being multifaceted and context-based, this researcher conducted a qualitative study in an attempt to identify QWL dimensions expected in the working environment of a hotel. 84 students and 64 employees from three hotel management institute and three hotel organization from Mangalore city in India participated through a purposeful sampling frame. Data were collected using interviews, focus group discussions and open-ended questionnaires, and analyzed in line with grounded theory method. The content analysis of the data yielded eight dimensions of QWL. Implications and limitations of this study along with areas for future research are discussed.     

Office automation: Assessing energy implications

The authors estimate the net-energy intensity of manual and automated offices. Subjective probability distributions have been used to characterize the considerable uncertainty about the value of a number of the coefficients that are required in such calculations. The current generation of automated offices appears to be more energy-intensive than conventional offices. The energy savings made possible by substituting electronic mail for conventional mail is small compared with this difference. The net impact of substitution for travel will, over the next decade, probably represent less than a few percent of the total energy used in all commuting and other business-related travel and could be either positive or negative.     

Explorations: Time-use surveys in the south

Abstract

Time-use surveys show how individuals spend their time during the day or week, which provides evidence of the gendered division of labor within households and the interdependence of women's and men's paid and unpaid work. Time-use experts in the South face similar challenges to those working in other countries, but they also have to come to terms with the restrictions faced in less developed contexts – notably higher illiteracy rates and limited statistical budgets. These Explorations bring together contributions from three experts on time-use survey design and administration working in three diverse Southern regions to highlight the ongoing processes of learning-by-doing and of building local expertise in these regions. Their discussion of methodological and logistical issues holds particular relevance for developing countries moving toward the implementation of time-use surveys. It also bears on more general feminist concerns regarding the classification and measurement of unpaid care.     

Some limit theorems in urn models with indistinguishable balls

Abstract

When n indistinguishable balls are distributed into m cells, there are two possible models (known as Bose-Einstein Statistics) depending on whether the cells are allowed to be empty or not. In these models, the possible limit laws of the number of cells containing k balls each are identified which are Normal, Poisson and degenerate. It is interesting to see that these are the only three limit laws of the occupancy variables studied here.     

Non-renewable resources: A review of long-term projections

This article reviews available estimates of long-term future demand for the major mineral resources, together with estimates of the total world endowment of each. The confrontation of these two sets of estimates is not to be viewed as an exercise in doomsday forecasting. Rather, it yields a set of indices of the lead times available for the exploration of solutions to the problems of the demand for, and the supply of, resources. It is not obvious that market forces will be able to cope with shortages swiftly and flexibly. There is thus a need for a continuing evaluation of the long-run resource implications of world economic expansion.