Rate of Foot-and-Mouth Disease Virus Transmission by Carriers Quantified from Experimental Data

Upon infection with foot-and-mouth disease virus (FMDV) a considerable number of animals become carriers of the virus. These carriers are considered to be a risk for new outbreaks, but the rate at which these animals can transmit the infection has not been quantified. An analysis was carried out using data from previously published experiments in order to quantify the transmission rate parameter β of FMDV infection from carriers to susceptible animals. The parameter β was estimated at 0.0256 (likelihood-based confidence interval: 0.008–0.059) infections per carrier per month. Moreover, analysis of published experimental data indicates that the proportion of FMDV carriers decreases at a rate of 0.115 per month. Both parameters obtained from this study are useful for quantitative risk analyses of the trade of animals from FMDV-infected areas or the lifting of vaccination programs.     

Efficient estimation for incomplete multivariate data

We review the Fisher scoring and EM algorithms for incomplete multivariate data from an estimating function point of view, and examine the corresponding quasi-score functions under second-moment assumptions. A bias-corrected REML-type estimator for the covariance matrix is derived, and the Fisher, Godambe and empirical sandwich information matrices are compared. We make a numerical investigation of the two algorithms, and compare with a hybrid algorithm, where Fisher scoring is used for the mean vector and the EM algorithm for the covariance matrix.     

Post-Separation Conflict Trajectories: A Longitudinal Study

Although previous studies have shown that parental separation and parental conflict contribute independently to the adaptation difficulties of young people, there is, as of yet, no precise portrait of how post-separation conflicts evolve. Indeed, some fundamental questions remain unanswered: (1) Do parents who experience few conflicts during their break-up continue to enjoy a harmonious relationship afterward? (2) When parents have a conflictual relationship in the first years after separating, do problems eventually subside? (3) Are a family's characteristics associated with the way a post-separation conflict evolves? The present, exploratory study attempts to provide some answers to these three questions. The sample was composed of 123 boys and girls from 8 to 11 years old. The children and their parents were interviewed on two separate occasions at a 1-year interval. The first interview (time 1) took place 2.5 years after the separation on average. The children were notably asked to give their perception of the parental conflict. Four post-separation conflict trajectories were brought to light. Analysis also targeted three more-specific variables that distinguished these conflict trajectories, namely family income, quality of the relationship with the mother, and the degree of agreement at the time of separation.     

The invention of religion: Aspects of the South African case

This paper examines the role played by popular culture in response to the effects of the unfolding social and political repression on the ordinary Zimbabwean after 2000. The arts is one sector where the Zimbabwean government fostered its repressive hegemony. An urban youth music genre called ‘urban grooves’ rose to prominence during the period under focus here and some of the artists colluded with the government in propagating an anti‐Western imperialism campaign. This paper evaluates the nature of the genre’s performance practices and its role in the government’s anti‐Western imperialism campaign. It also discusses the complexities associated with notions of complicity and resistance as urban grooves artists resisted both Western hegemony, as per the government’s campaign, and subverted the same government’s censorship of the urban youth’s and the general society’s imaginary and other freedoms.     

Social security reforms and early retirement

Many reform proposals of the social security systems in various OECD economies suggest to scale down the non-actuarial parts of the pension systems. These reforms have a flavor of increased efficiency at the costs of welfare losses for low-income individuals. Assessing the economic effects, we investigate five different reform proposals by means of a numerical overlapping generations model for the Norwegian economy. The model features an endogenous retirement age and heterogeneous individuals within generations. It turns out that the various reforms, which scale down the public non-actuarial pension system, lead to increases in the retirement age and steady-state welfare gains for all income classes. Received: 7 December 2000/Accepted: 29 January 2002 All correspondence to ?ystein Th?gersen. Financial support from the Research Council of Norway (The Economic Research Program on Taxation) is gratefully acknowledged. We are indebted to Lans Bovenberg, John Ermisch, Erling Steigum and two referees for valuable comments and useful discussion. Responsible editor: John F. Ermisch.     

Partner + Children = Happiness? The Effects of Partnerships and Fertility on Well‐Being

Economic and rational‐choice theories suggest that individuals form unions or have children because these decisions increase their subjective well‐being or “happiness.” We investigate this relation using within‐MZ (identical) twin pair estimates to control for unobserved factors, such as optimistic preferences, that may simultaneously affect happiness, partnerships, and fertility. Our findings, based on Danish twins aged 25–45 and 50–70 years old, include the following. (1) Currently being in a partnership has large positive effects on happiness. (2) A first child substantially increases well‐being, in analyses without controls for partnerships, and males enjoy an almost 75 percent larger happiness gain from a first‐born son than from a first‐born daughter; however, only females enjoy a happiness gain from the first‐born child with controls for partnerships. (3) Additional children beyond the first child have a negative effect on subjective well‐being for females, while there is no effect for males. (4) Ever having had children does not significantly affect the subjective well‐being of males or females aged 50–70 years.     

Premium differentiation in the Unemployment Insurance system and the demand for labor

We simulate the effect of the introduction of premium differentiation (experience rating) in the Dutch Unemployment Insurance system on the demand for labor for a variety of sectors in the Dutch economy. For the simulations we use the Bentolila and Bertola (1990) framework as a point of departure. In the simulations, the introduction of experience rating is modeled as expenditure neutral: in the absence of premium differentiation the cost of financing UI is modeled as a wage tax (independent of the number of workers fired by the firm), whereas in the presence of experience rating this cost is attributed to firing cost (affected by the firing action). Thus, the introduction of experience rating results in a shift from wage cost to firing cost. Following the political debate on the issue in the Netherlands, we assume that the introduction of experience rating does neither lead to a change in tax rates paid by workers nor to a change in eligibility rules or replacement rates of benefit claimants. Specific attention is paid to the distinction between young and old workers . In the model, labor adjustment costs (hiring and firing costs) are linear. The model allows for uncertainty in the business cycle.All correspondence to Hans Bloemen. Responsible editor: Alessandro Cigno