The effects of traffic noise on tadpole behavior and development

Urban Ecosystems - Traffic noise is known to negatively affect many wildlife species by interfering with foraging behavior. Frogs often lay their eggs in roadside ditches because they are...     

Multiple event times in the presence of informative censoring: modeling and analysis by copulas

Motivated by a breast cancer research program, this paper is concerned with the joint survivor function of multiple event times when their observations are subject to informative censoring caused by a terminating event. We formulate the correlation of the multiple event times together with the time to the terminating event by an Archimedean copula to account for the informative censoring. Adapting the widely used two-stage procedure under a copula model, we propose an easy-to-implement pseudo-likelihood based procedure for estimating the model parameters. The approach yields a new estimator for the marginal distribution of a single event time with semicompeting-risks data. We conduct both asymptotics and simulation studies to examine the proposed approach in consistency, efficiency, and robustness. Data from the breast cancer program are employed to illustrate this research.

     

Does a universal non-contributory social pension make sense for rural China?

China’s pension reform during the past three decades has allowed a majority of China’s population to be covered by a pension scheme. Of particular note has been the New Rural Pension Scheme (NRPS), a voluntary programme introduced starting in 2009. One goal of our analysis is to assess that pension scheme, using a variety of sources of information including data drawn from recent (2013 and 2015) nationwide China Health and Retirement Longitudinal Surveys (CHARLS). Our analysis involves an exploration of differences between the generosity and structure of the NRPS and other pension schemes currently in place. We also explore the feasibility of reforming the current “quasi-social pension” component of the NRPS by substituting a universal non-contributory social pension pillar. In connection with our assessment of the NRPS, we note the unusually low benefit levels for rural China.     

Ambiguity and price competition

Theory and Decision - There are few models of price competition in a homogeneous-good market which permit general asymmetries of information amongst the sellers. This work studies a price game with...     

Changes in preschool children’s social engagement positively predict changes in social competence: A three‐year longitudinal study of portuguese children

To test the hypothesis that social engagement is a foundational aspect of other peer social competence indicators during early childhood, 160 Portuguese preschool children (“3‐year‐olds”) were observed at least in two different school years, using a battery of validated social competence assessments based on direct observations and child interviews. Multilevel growth models tested whether social engagement predicted initial values and linear changes in the other social competence indicators. Results were consistent with the hypothesis, insofar as both initial values and changes in social engagement significantly predicted initial values and changes in other social competence indicators. Additionally, the number of children's reciprocated friendships was also predicted by social engagement. These results are discussed from the perspectives of conceptual frameworks that consider individual differences in social competence during early childhood as a consequence of attachment histories and/or emotional competence.     

A study of internal migration in England and Wales

Abstract The main trend in urban/rural migration is a continuous gain, in net terms, of towns from villages and large cities. But this is a result of two distinct migration streams associated with the process of family formation. While before marriage there is positive net migration from villages to both large cities and towns (and from large cities towards towns), after marriage there is a tendency for couples to move towards villages. This is explained by the desire of families, particularly those belonging to the middle class to move out of the urban centres to better accommodation in smaller communities. Considerable variations in migrations within and into regions are observed. These reflect the continuation oflong-term trends in internal migration (as described in Part I of this paper) in particular, population dispersal from Greater London and larger distance migration into the Southern and Eastern regions. Some social characteristics of migrants and non-migrants are compared. Associations between the intensity of internal migration on the one hand, and occupational status, education, social mobility and family size on the other are observed. An attempt is made to assess the extent of migration associated with the marriage process. Although this process increases mobility, its relative contribution to total adult mobility appears to be only slight.     

When bubbles burst: Mimetic insights into minimising confidentiality breaches

This paper presents a theoretical model to help managers visualise and manage confidential situations more effectively. The model metaphorically likens a confidential setting to the properties of a soap bubble, e.g. elastic expansion or contraction, minimal surface area to contain a given volume, fragility, surface tension, pressure, stress, strain and the potential for bursting thereby releasing the contents to the external environment. We explore the conceptual developments in two phases. Firstly, looking at how a bubble and confidential scenario form and grow. Secondly, we consider how a bubble may burst and map these forces to ways in which confidentiality may be breached. Many attributes are mapped, the key ones being: the embedded value within the system, the criticality of maintaining confidentiality, increasing pressure, the corresponding stress/strain dynamics and the levels of trust between stakeholders. Key research propositions are derived from the model which aims to minimise the risk of a confidentiality breach.