An affine‐invariant multivariate sign test for cluster correlated data

The author presents a multivariate location model for cluster correlated observations. He proposes an affine‐invariant multivariate sign statistic for testing the value of the location parameter. His statistic is an adaptation of that proposed by Randles (2000). The author shows, under very mild conditions, that his test statistic is asymptotically distributed as a chi‐squared random variable under the null hypothesis. In particular, the test can be used for skewed populations. In the context of a general multivariate normal model, the author obtains values of his test's Pitman asymptotic efficiency relative to another test based on the overall average. He shows that there is an improvement in the relative performance of the new test as soon as intra‐cluster correlation is present Even in the univariate case, the new test can be very competitive for Gaussian data. Furthermore, the statistic is easy to compute, even for large dimensional data. The author shows through simulations that his test performs well compared to the average‐based test. He illustrates its use with real data.     

Optimal pension funding with demographic instability and endogenous returns on investment

This paper tries to explore some optimal funding policies for pension systems in a general equilibrium setting where funding affects returns on investment and wages through its impact on capital formation. This is done in the context of irregular demographic evolutions such as those expected in developed countries for the next century. Particular attention is given to the intergenerational welfare criterion which is used for designing optimal policies. It appears that funding receives low justification with a welfare criterion which assumes a high substitutability between consumptions of successive cohorts, implying a low concern for intergenerational equity. Funding is highly justified in the opposite case where a high level of consumption for some cohorts is not considered as a compensation for low consumption by others. However the optimal patterns of transfers and savings which are found in this latter case are not straightforward. Some simpler funding rules are explored in the last section of this paper, which show that non-optimal funding may imply, on the contrary, a high level of inequality between subsequent generations.Paper presented at the ISPE-conference Fiscal implications of an ageing population, May–June 1990 at Vaalsbroek, The Netherlands. We thank Pierre Pestieau for his remarks on a first draft of this paper. We also thank for their comments our two discussants Carol Propper and Lans Bovenberg, as well as other participants to the ISPE Conference. Any errors are, of course, ours.     

The proximity filter: the effect of distance on media coverage of the Christchurch mosque attacks

ABSTRACT

The intense media coverage in New Zealand and Australia of the Christchurch mosque attacks exhibited significant disparity in editorial decision-making between the two countries. This research interrogates the different approaches taken in newsrooms and how these differences were manifested in broadcasts and publications. New Zealand media were focused largely on empathetic coverage of victims and resisted the alleged gunman's attempts to publicise his cause while their Australian counterparts showed no such reluctance and ran extended coverage of the alleged perpetrator, along with material ruled objectionable in New Zealand. It finds the editorial focus in each case exhibits the effect of proximity, identified in literature on empirical ethical decision-making as a factor in applied ethicality. The authors conclude that a proximity filter was used by New Zealand media who identified the victims as part of their own community, but the events of 15 March 2019 were seen as ‘foreign’ by Australian journalists who used perceived distance as justification for extremely graphic content.     

Dissemination to research subjects: operationalizing investigator accountability

Recent articles have argued from principles of bioethics for the right of research subjects to receive the results of the studies in which they have participated. We argue that accountability is a powerful tool of meso-level analysis appropriate to reasoning about answerability in research ethics, and that it captures the responsibility of researchers to disseminate study results to research subjects. We offer the following features of the research situation as relevant to the manner of dissemination to study subject, in addition to factors already proposed in the literature (risk and impact on health outcome): (a) features of the research subject in relation to identity, personal investment, disease, and community; (b) characteristics of the research study and field of inquiry in relation to certainty and significance; and (c) relationships among the research subjects and the healthcare workers involved in their care and in the research.     

Simulating space-time random fields with nonseparable Gneiting-type covariance functions

Statistics and Computing - Two algorithms are proposed to simulate space-time Gaussian random fields with a covariance function belonging to an extended Gneiting class, the definition of which...     

Food in a row: urban trees offer valuable floral resources to pollinating insects

Urbanization affects the availability and diversity of floral resources (pollen and/or nectar) for wild pollinating insects. For example, urban green areas are characterized by an abundance of ornamental plant species. Increasingly, trees are planted to improve the aesthetics of urban streets and parks. These urban trees might offer important floral resources to pollinating insects. To examine the suitability of urban trees as resources for pollinating insects, we investigated the chemical composition of pollen and nectar as well as the amount of nectar produced by the nine major insect-pollinated tree species planted in cities of Western Europe, namely Acer pseudoplatanus, Aesculus carnea, A. hippocastanum, Robinia pseudoacacia, Tilia cordata, T. x euchlora, T. x europaea, T. platyphyllos and T. tomentosa. The analyses revealed that globally the Tilia trees provide pollen with lower contents of polypeptides, amino acids and phytosterols compared with the other species. Urban tree flowers offer abundant nectar with relatively high sugar contents (0.16–1.28 mg/flower); sucrose was the predominant sugar in all nectars. The investigated tree species could therefore be considered in future city plantings.     

International Migrant Remittances and Labour Supply in Nigeria

The study analyses how remittances to Nigeria affect the labour supply of recipients using Propensity Score Matching (PSM) and a Log‐Linear regression model, with data from the 2013 Nigerian General Household Survey. The PSM results show that for the entire sample, the difference between the average amount of labour supplied per week by those that receive remittances and the amount they would have supplied without remittances is insignificant. The marginal impact analysis also shows that, ceteris paribus, the average labour supply for all recipients is inelastic to remittances. The results from the sub‐group analysis, however, show that receiving remittances negatively affects the labour supply of the self‐employed in agriculture, teenagers and the elderly. These results led us to the recommendation that policies to increase the inflow of remittances should be encouraged but in tandem with programmes to educate farmers on the benefit of investing remittances received in their farming business.     

Presto: a software package for the simulation of diffusion processes

Conclusion Presto is a software which automatically generates FORTRAN code corresponding to approximation procedures of the solutions of stochastic differential systems.At the present time, it answers only to a few needs, but a diversification of its users and its simple internal structure could easily permit it to be developed towards a more ambitious system.Finally, let us mention that Presto is an INRIA product, which is free for academic institutions, universities, etc, which already have MAPLE and X-Windows licences. Presto can be run on any UNIX station under X-Windows environment.