A Markovian susceptible --> infectious --> removed (SIR) epidemic model is considered in a community partitioned into households. A vaccination strategy, which is implemented during the early stages of the disease following the detection of infected individuals is proposed. In this strategy, the detection occurs while an individual is infectious and other susceptible household members are vacci...

Non-linear dose response relationships pose statistical challenges for their discovery. Even when an initial linear approximation is followed by other approaches, the results may be misleading and, possibly, preclude altogether the discovery of the nonlinear relationship under investigation. We review a variety of straightforward statistical approaches for detecting nonlinear relationships and ...

The supply behavior of labor frequently depends on the demand conditions that prevail on the labor market. If demand is inadequate, households may send additional household members, who otherwise would not have worked, to look for work, for fear that the main income earner may lose his job. This paper is a study of the theoretical consequences of this ’’added worker’’ affect. It is shown that t...

The objective of this study was to identify and describe levels of household economic vulnerability in HIV-affected communities in Côte d'Ivoire, defined as those with a high prevalence of HIV and large numbers of orphans and vulnerable children. We conducted a cross-sectional survey of 3,749 households in five health regions of Côte d'Ivoire. Using principal component analysis, we attempted to...

Children's ability to place fractions on a number line strongly correlates with math achievement. But does the number line play a causal role in fraction learning or does it simply index more advanced fraction knowledge? The number line may be a particularly effective representation for fraction learning because its properties align with the desired mental representation and take advantage of p...

The semi-private property rights arrangement called the Household Production Responsibility System (HPRS) was started in the early 1980s in Xilingol pasture of Inner Mongolia (China), and stimulated the development of stockbreeding. The grassland has been degrading severely with increasing numbers of livestock. Based on a historical review of property rights regimes in Inner Mongolia and empiri...

BACKGROUND Emerging communication technologies have had an impact on population-based telephone surveys worldwide. Our objective was to examine the potential biases of health estimates in South Australia, a state of Australia, obtained via current landline telephone survey methodologies and to report on the impact of mobile-only household on household surveys. METHODS Data from an annual mult...

The rationale for the use of an advance respondent letter is based on the experience of survey researchers that contact before an actual interview attempt “warmsup” respondents, hopefully making them more positively disposed toward participation than if they were only to receive a “cold call.” The logic is that using advance respondent letters will increase response rates, thereby reducing the ...

This article argues that a knowledge and practice defi cit, and the inability of higher education institutions to professionalise development are key lacunae which need to be overcome. However, this will need the university to reinvent itself and for elite institutions to develop a more accessible notion of knowledge and rigour. The people of India must add a hot summer, a defi cient monsoon, a...

BACKGROUND Telephone surveys based on samples of landline telephone numbers are widely used to measure the prevalence of health risk behaviours such as smoking, drug use and alcohol consumption. An increasing number of households are relying solely on mobile telephones, creating a potential bias for population estimates derived from landline-based sampling frames which do not incorporate mobile...