Blur-generated non-separable space–time models

Statistical space–time modelling has traditionally been concerned with separable covariance functions, meaning that the covariance function is a product of a purely temporal function and a purely spatial function. We draw attention to a physical dispersion model which could model phenomena such as the spread of an air pollutant. We show that this model has a non-separable covariance function. The model is well suited to a wide range of realistic problems which will be poorly fitted by separable models. The model operates successively in time: the spatial field at time t +1 is obtained by 'blurring' the field at time t and adding a spatial random field. The model is first introduced at discrete time steps, and the limit is taken as the length of the time steps goes to 0. This gives a consistent continuous model with parameters that are interpretable in continuous space and independent of sampling intervals. Under certain conditions the blurring must be a Gaussian smoothing kernel. We also show that the model is generated by a stochastic differential equation which has been studied by several researchers previously.     

A response to criticism of our estimates of under-5 mortality in Iraq, 1980-98

According to estimates published in this journal, the number of deaths of children under 5 in Iraq in the period 1991-98 resulting from the Gulf War of 1991 and the subsequent imposition of sanctions by the United Nations was between 400,000 and 500,000. These estimates have since been held to be implausibly high by a working group set up by an Independent Inquiry Committee appointed by the United Nations Secretary-General. We believe the working group's own estimates are seriously flawed and cannot be regarded as a credible challenge to our own. To obtain their estimates, they reject as unreliable the evidence of the 1999 Iraq Child and Maternal Mortality Survey--despite clear evidence of its internal coherence and supporting evidence from another, independent survey. They prefer to rely on the 1987 and 1997 censuses and on data obtained in a format that had elsewhere been rejected as unreliable 30 years earlier.     

The magnitude of educational disadvantage of indigenous minority groups in Australia

Indigenous groups are amongst the most disadvantaged minority groups in the developed world. This paper examines the educational disadvantage of indigenous Australians by assessing academic performance at a relatively early age. We find that, by the age of 10, indigenous Australians are substantially behind non-indigenous Australians in academic achievement. Their relative performance deteriorates further over the next 2 years. School and locality do not appear to be important determinants of the indigenous to non-indigenous achievement gap. However, geographic remoteness, indigenous ethnicity and language use at home have a marked influence on educational achievement. A current focus of Australian indigenous policy is to increase school resources. Our results suggest that this will not eliminate indigenous educational disadvantage on its own.

Migration Plans and Received Remittances: Evidence from Fiji and Tonga1

This paper investigates the relationship between remittances and migration intentions in the source country using data from households in the Pacific island countries of Tonga and Fiji. Unlike previous research it accounts for potential endogeneity in the relationship between remittances and intentions and also includes households that receive remittances but do not have current migrants. We find a positive impact of remittances on intentions. The impact of remittances on intentions is stronger in a country with a longer history of migration and stronger in households with current migrants than those without migrants. These results provide new evidence on the role of remittances in the development of migration chains.     

Parallels in propaganda? A comparative historical analysis of Islamic State and the Nazi Party

ABSTRACT

This article responds to calls for more comparative historical studies in public relations history across nations and cultures with a comparative analysis of the propaganda operations of Islamic State with the Nazi Party. This comparative historical approach aims to reduce the uncertainty associated with extremist terrorism and bring a historic-communicative perspective to an organization that politicians and commentators arguably overestimate in what has been described as the “epistemological crisis” of Western counterterrorism. This investigation attempts a methodological expansion of public relations historiography by applying the theoretical approach of historical institutionalism as basis for comparison between the two institutions alongside conventional content and artefact analysis. The project identifies ten parallels in propaganda and concludes that some of these commonalities – including a focus on engaging and recruiting young people, for example – can provide historically-derived guidance on counter terrorism responses in the communicative sphere.     

Parenting and Digital Media: From the Early Web to Contemporary Digital Society

Parents have accessed websites, online discussion forums and blogs for advice, information and support since the early days of the World Wide Web. In this article, we review the literature in sociology and related social research addressing the ways in which digital media have been used for parenting‐related purposes. We begin with the longer‐established media of parenting websites, online discussion forums, blogs, email, mobile phones and message and video services and then move on to the newer technologies of social media and apps. This is followed by a section on data privacy and security issues. The concluding section summarises some major issues arising from the review and points to directions for further research.     

Towards optimal scaling of metropolis-coupled Markov chain Monte Carlo

We consider optimal temperature spacings for Metropolis-coupled Markov chain Monte Carlo (MCMCMC) and Simulated Tempering algorithms. We prove that, under certain conditions, it is optimal (in terms of maximising the expected squared jumping distance) to space the temperatures so that the proportion of temperature swaps which are accepted is approximately 0.234. This generalises related work by physicists, and is consistent with previous work about optimal scaling of random-walk Metropolis algorithms.     

Modeling data with structural and temporal correlation using lower level and higher level multilevel models

Novel imaging techniques are playing an increasingly important role in drug development, providing insight into the mechanism of action of new chemical entities. The data sets obtained by these methods can be large with complex inter-relationships, but the most appropriate statistical analysis for handling this data is often uncertain--precisely because of the exploratory nature of the way the data are collected. We present an example from a clinical trial using magnetic resonance imaging to assess changes in atherosclerotic plaques following treatment with a tool compound with established clinical benefit. We compared two specific approaches to handle the correlations due to physical location and repeated measurements: two-level and four-level multilevel models. The two methods identified similar structural variables, but higher level multilevel models had the advantage of explaining a greater proportion of variation, and the modeling assumptions appeared to be better satisfied.     

Lay Understandings of Health among Dai Lue in Xishuangbanna,China

This study analyses lay understandings of health among Dai Lue, an ethnic minority in China, and how they are played out in help-seeking practices. Interviews and focus groups with sixty-three rural villagers in Xishuangbanna, southwest China revealed that health was largely interpreted as a social experience embedded in Dai Lue culture and ethnicity. Salient to this interpretation was family, community connectedness and Dai Lue ceremonies and festivals, as well as connections with a socio-political context. Ethnicity and ‘othering’ was an important thread running through their lay health beliefs, especially distinctions between Dai and Han. The health research, policy and practice implications of the findings are also discussed, and are likely to be applicable to other ethnic minorities in China.