Symmetry and asymmetry in working and commuting arrangements between partners in the Netherlands : does the residential context matter?

Time spent on work and commuting within dual-earner households is often analysed separately for individuals, but this does no justice to the reality of dual-earner households where decisions on work and commuting are made in a household context. This paper reports on a quantitative study of the impact of the residential context on working arrangements and commuting arrangements of partners in couple and family households. Using multinomial logistic regression, we analysed data from the 2002 Netherlands Housing Demand Survey and the 2004 ABF Real Estate Monitor. The results show a (gendered) effect of residential location in terms of degree of urbanisation and job access on both working and commuting arrangements. Good access to jobs makes it more likely that couples have a symmetric full-time working arrangement and also more likely that both partners work far away from home. Those in symmetric full-time working arrangements are also those most likely to be in symmetric closePostprintPeer reviewe

Salinity effects on competition between cryptic species of the nematode Rhabditis (Pellioditis) marina

Behind the morphological similarity of many species, a substantial hidden genetic diversity can be found. This cryptic diversity has been well documented in the marine nematode, Rhabditis (Pellioditis) marina, where several cryptic species occur sympatrically. Despite the growing knowledge about its cryptic diversity, little is known about potential differences in the ecology and functional roles of the different species. In this experiment four cryptic species of Rhabditis (Pellioditis) marina were reared together, starting from identical initial abundances at two different salinity concentrations to investigate differences in their environmental preferences and how they may affect the outcome of their competitive interactions. Every fifth day of the experiment one third of the adults was removed from the population for analyzing the genetic composition of the population; adult and juvenile population dynamics were also examined. The first results show a difference in population dynamics dependent on the salinity. At low salinity, a population crash occurred after 15 days in all the populations. Only half of the populations recovered from this bottleneck and reached higher abundances than before. Genetic analyses revealed that the composition of these populations consists solely of individuals of one cryptic species. This effect was totally absent in the populations reared at higher salinity. Two explanations are possible: (1) the different cryptic species have different survival rates at different salinities and (2) the competitive interactions between them differ at different salinities. We are currently identifying the sampled adults using a restriction fragment analysis to assess these explanations and to elucidate the effect of salinity on the coexistence of cryptic species of Rhabditis (Pellioditis) marina

Hybrid RANS/PDF calculations of sydney swirling flames

In this work, we perform steady 2D axisymmetric RANS and hybrid RANS/PDF calculations to predict the turbulent flow and mixing fields of swirling inert flows and flames. The cases studied, N29S054 and SM1 respectively, are bluff body burner flows, studied experimentally at Sydney University. Turbulence is modeled with a non-linear k-ε type model, taking into account effects of rotation and streamline curvature on the turbulence. Flow field predictions are in reasonable agreement with experimental data. For the reacting flow, agreement for mean mixture fraction and mixture fraction variance with experimental results is less satisfactory. Yet, the mean temperature field is quite well reproduced. We compare presumed and transported scalar PDF simulation results, with the same laminar flamelet model for chemistry. The influence of the micro-mixing model is small in our case. The mixing model constant Cφ, has a stronger influence, through the mixture fraction variance

The asymptotics of group Russian roulette

We study the group Russian roulette problem, also known as the shooting problem, defined as follows. We have $n$ armed people in a room. At each chime of a clock, everyone shoots a random other person. The persons shot fall dead and the survivors shoot again at the next chime. Eventually, either everyone is dead or there is a single survivor. We prove that the probability $p_n$ of having no survivors does not converge as $n\to\infty$, and becomes asymptotically periodic and continuous on the $\log n$ scale, with period 1.Comment: 26 pages, 1 figure; Mathematica notebook and output file (calculated exact bounds) are included with the source file