The importance of non-linearity: A comment on the views of Taylor

Summary Taylor's (1984) view that his power law is better measurement of the distribution pattern of animals than 1/k, I _ρ and relation because almost all the data on means and variances of given species could be fitted by the power low, was critisized. Changes in values of 1/k, I _ρ and suggest the change of distribution pattern of the species, but the data can still be fitted by the power law because of the great linearizing power of log-log plots, and, using the power law only, we shall overlook the information on the meaningful changes in the distribution pattern.     

The adaptive significance of leaf-mining pattern as an anti-parasitoid strategy: A theoretical study

Summary An adaptive significance of linear leaf mining patterns as the anti-parasitoid strategy is theoretically analysed. In the model, a leaf-miner is allowed to move in one of four ways; mining ahead in unexploited area of a leaf, backtracking, branching off from the backtracking mine, and crossing the previous mine. The model parasitoid searches for the leaf-miner by tracing the mine by the tactile cue of mine surface after detecting the mine. The average duration from detecting the mine to finding the leaf-miner host is calculated for various patterns of mining, changing numbers of branches and of crosses. This average duration becomes longer when the leaf-miner stays near either end of the mine compared with when staying near its center. It is also prolonged as the numbers of branches and of crosses increase.     

Children and return migration

We explore reasons for return migrations which are motivated by immigrants concerns about their children. We develop a simple model, where parents have paternalistic preferences. We show that parental concerns about the child may lead to an increase, or to a decrease in the tendency to return to the home country. Our model suggests that return plans of the parent may respond differently to the presence of daughters than to the presence of sons. The empirical test of our models relies on the exogeneity of childrens gender. We use a survey panel data set, containing information on both return realisations over 14 years, and intended return plans. Our results lend support to the hypothesis that children influence return plans of their parents.I am grateful to Jerome Adda, Jaap Abring, David Card, Slobodan Djajic, and Ian Preston for comments on earlier versions of this paper. Responsible editor: Christoph M. Schmidt.     

Child schooling and contraceptive use in rural Africa: A Ghanaian case study

In this study, I examine the contributions of childrens schooling to fertility decline in Africa. I use cross-sectional data collected in the late 1980s to look at how household child schooling patterns and community access to schools affect contraceptive use among rural Ghanaian women. My results indicate that the schooling of children is associated very strongly with increased use of modern and traditional contraceptive use and thereby suggest that educational policy has played a role in initiating and sustaining fertility decline in Ghana and possibly elsewhere in Africa.     

Arts and the quality of life: an Exploratory study

The aim of this investigation was to measure the impact of the arts broadly construed on the quality of life. A randomly drawn household sample of 315 adult residents of Prince George, British Columbia served as the working data-set. Examining zero-order correlations, among other things, it was found that playing a musical instrument a number of times per year was positively associated with general health (r = 0.37), while singing alone a number of hours per week was negatively associated with general health (r = ?0.19). The strongest positive associations with life satisfaction are satisfaction obtained from gourmet cooking and embroidery, needlepoint or cross-stitching, at r = 0.39 andr = 0.32, respectively. The satisfaction obtained from gourmet cooking (r = 0.35) and buying works of art (r = 0.32) were the most positive influences on happiness. The strongest associations with the Index of Subjective Well-Being are the satisfaction obtained from gourmet cooking (r = 0.37) and the satisfaction obtained from knitting or crocheting (r = 0.34). Examining multivariate relations, it was found that eight predictors combined to explain 59% of the variance in life satisfaction scores, with self-esteem satisfaction (β = 0.35) and friendship satisfaction (β = 0.27) most influential. Among the arts-related predictors in the eight, singing alone was fairly influential and negative (β = ?0.18), while the satisfaction obtained from reading to others (β=0.08) and the Index of Arts as Self-Health Enhancers (β = 0.11) were somewhat less influential. When the arts-related predictors were combined with a set of domain satisfaction predictors, total explanatory power was increased by only 3 percentage points. Seven predictors could explain 58% of the variance in satisfaction with the overall quality of life scores. Of the arts-related predictors, only time spent going to non-art museums was significant (β = 0.07). Arts-related predictors did not increase explanatory power at all beyond that obtained from domain satisfaction variables alone. Eight predictors explained 42% of the variance in happiness scores, with the most influential predictors including satisfaction with self-esteem (β = 0.37) and financial security (β = 0.21), followed by the Index of Arts as Self-Developing Activities (β = 0.18). Arts-related predictors added 3 percentage points of explanatory power to that obtained from domain satisfaction scores. Seven predictors could explain 65% of the variance in scores on the Index of Subjective Well-Being, led by self-esteem satisfaction (β = 0.35) and financial security satisfaction (β = 0.30). The Index of Arts as Community Builders had a modest influence (β = 0.11), but all together, arts-related predictors increased our total explanatory power by a single percentage point. Summarizing these multivariate results, it seems fair to say that, relative to the satisfaction obtained from other domains of life, the arts had a very small impact on the quality of life (measured in four somewhat different ways) of a sample of residents of Prince George who generally cared about the arts. Even in absolute terms, arts-related activities could only explain from 5% to 11% of the variance in four plausible measures of the self-perceived quality of respondents’ lives. By comparing the composition of our sample with census data from 2001, it was demonstrated that the sample was not representative of residents of our city. It would, therefore, be wrong to generalize our findings to the whole population of Prince George or to any larger population.     

Do Demographic Characteristics Make a Difference to Burnout among Hong Kong Secondary School Teachers?

This study aims to investigate the relationship between teachers’ demographic variables and burnout in Hong Kong using the Maslach Burnout Inventory. It is found that when compared with the North American normative data, Hong Kong teachers scored in the average range of burnout in emotional exhaustion and personal accomplishment while they scored in the low range of burnout in depersonalization. Gender differences were found in all three burnout syndromes, and teachers who were younger, unmarried, without religious beliefs, less experienced, without finishing professional training and of junior rank were more consistently burned out. Whereas age was the strongest predictor for emotional exhaustion and depersonalization, teachers’ rank is the best predictor for personal accomplishment. However, the effect of demographic characteristics of teachers on burnout is not that salient.     

Effects of sexual preferences on earnings in the Netherlands

A small literature suggests that bisexual and homosexual workers earn less than their heterosexual fellow workers and that a discriminating labormarket is partly to blame. In this paper we examine whether sexual preferences affect earnings at the beginning of working careers in the Netherlands. Using an alternative, and quite possibly a better, measure of sexual identity, we find (i) that young and highly educated gay male workers earn about 3% less than heterosexual men; (ii) that similarly qualified lesbian workers earn about 3% more than their heterosexual female co-workers; and (iii) that among homosexual workers the gender gap is not observed. From this we conclude that the Dutch labor market does not discriminate on the basis of both sexual orientation and gender in entry-level jobs.All correspondence to Erik Plug. Both authors would like to thank Jim Albrecht, Mikael Lindahl, Hessel Oosterbeek, Susan Vroman and an anonymous referee for their helpful comments on earlier drafts of this paper. Responsible editor: Daniel S. Hamermesh.     

Skill premium effects on fertility and female labor force supply

In the last twenty years the United States has seen a positive relationship between female labor supply and total fertility rates, which differs from the pattern observed over the preceding years. We construct a general equilibrium overlapping generations model capable of generating this changing relationship between fertility and female labor supply. We argue that skilled biased technological change in recent decades has increased the skill premium and has therefore decreased the relative cost of (unskilled) child care services. The positive effect of the increase in female mean wages on fertility rates, and the inducement for labor force participation provided by the reduction in the relative cost of child care services, generated the positive relationship between fertility rates and female labor force participation in the last two decades.All correspondence to Amaia Iza. This paper has benefited particularly from comments by Juan Carlos Conesa, Pedro Mira and Sara de la Rica. We also acknowledge countless conversations with María Paz Espinosa and useful comments from Jaime Alonso, Jose María Da-Rocha, Tim Kehoe, José Victor Rios-Rull, when the paper was presented at the IV Workshop of Dynamic Macroeconomics held in Vigo (Spain, July 1999) and in Universidade de Vigo (October, 2000). We also thank an anonymous referee whose comments enabled us to improve the paper considerably. Financial support from Universidad del País Vasco 9UPV 00035.321-13511/2001, Ministerio de Educación y Ciencia PB097-0620, MCYT BEC2000/1394 and Instituto de la mujer (Ministerio de Trabajo y Asuntos Sociales) MTAS 33/00 is gratefully acknowledged. Any remaining errors are the authors responsibility. Responsible editor: Junsen Zhang.