Quantifying Finite Temperature Effects in Atom Chip Interferometry of Bose-Einstein Condensates

We quantify the effect of phase fluctuations on atom chip interferometry of Bose-Einstein condensates. At very low temperatures, we observe small phase fluctuations, created by mean-field depletion, and a resonant production of vortices when the two clouds are initially in anti-phase. At higher temperatures, we show that the thermal occupation of Bogoliubov modes makes vortex production vary smoothly with the initial relative phase difference between the two atom clouds. We also propose a technique to observe vortex formation directly by creating a weak link between the two clouds. The position and direction of circulation of the vortices is subsequently revealed by kinks in the interference fringes produced when the two clouds expand into one another. This procedure may be exploited for precise force measurement or motion detection.Comment: 7 pages, 5 figure

Overview of pedal cyclist traffic casualties in South Australia

Characteristics of pedal cycle crashes (as reported to the police) in South Australia, and how they have changed over the period 1981-2004, are examined. The paper describes both the present situation (2001-2004) and how it has changed since 1981; both child and adult casualties; both the numbers of casualties and the proportions seriously injured; and both factors that are commonly tabulated and some that are relatively unusual. In 1981, pedal cyclist casualties were mostly children and teenagers, but in 2004, pedal cyclist casualties were mostly spread across the age range from 16 to 49. Child pedal cyclist casualties reached a maximum in 1982-1987, and have fallen sharply since. Adult pedal cyclist casualties reached a maximum in 1987-1990, and then fell. Concerning the proportion of casualties seriously injured (i.e., killed or admitted to hospital), in 2001-2004 this proportion among adults (16+) was 12% when the speed limit was 60 km/h or less, and 33% when the speed limit was 70 km/h or higher. Among the four most frequent types of crashes (right angle, side swipe, right turn, and rear end), the proportions of adult casualties seriously injured were 11%, 11%, 16%, and 18%. The proportion was 14% for male drivers of the motor vehicle and 9% for female drivers; it was 17%, 15%, 15%, 14%, 10%, and 11% for motor vehicle driver age groups 16-19, 20-29, 30-39, 40-49, 50-59, and 60-99.T. P. Hutchinson, C. N. Kloeden, and A. D. Lon

Choice of licensing method and crashes of young drivers

Five years of data (1998-2002) were used to examine whether there was a relationship between the method of driver licensing - Competency Based Training (CBTA) or Vehicle On-Road Test (VORT) - and the subsequent crash experience of young drivers, using logistic regression analysis.Robert Anderson, Craig Kloeden, TP Hutchinson and AJ McLea

Are Fish Wild?

As the global biodiversity crisis continues, it is important to examine the legislative protection that is in place for species around the world. Such legislation not only includes environmental or wildlife law, but also trade law, such as the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which gets transposed into national legislation. This commentary analyses legislative definitions of wildlife, whether or not that includes fish, which has implications for fish welfare, use of fish for food security, and biodiversity conservation when fish, or other wildlife, are excluded. Through a legislative content analysis of the 183 parties’ legislation of CITES, we explore whether fish are afforded the same protections as other species by being included in legal definitions of wildlife. We found that while a majority of CITES parties’ legislation appear to define fish as wildlife, there are a number of instances where this is unclear or not the case, and this could have significant ramifications for the welfare of non-human animals, their use, and conservation

PTC Taste Threshold Distributions and Age in Mennonite Populations

This is the published version. Copyright 1982 Wayne State University Press.A number of studies report an impairment of the genetically inherited ability to taste PTC as a function of age, but ignore the cumulative effect of smoking on taste deterioration. This study examines the effect of aging on taste sensitivity in nonsmoking Mennonite populations. The results obtained preclude a cause and effect relationship between age and PTC taste sensitivity. These results are congruent with the claims which ascribe the observed deterioration in PTC taste sensitivity to the cumulative effects of smoking, rather than to the effects of aging per se

Gapless finite-TT theory of collective modes of a trapped gas

We present predictions for the frequencies of collective modes of trapped Bose-condensed $^{87}$Rb atoms at finite temperature. Our treatment includes a self-consistent treatment of the mean-field from finite-$T$ excitations and the anomolous average. This is the first gapless calculation of this type for a trapped Bose-Einstein condensed gas. The corrections quantitatively account for the downward shift in the $m=2$ excitation frequencies observed in recent experiments as the critical temperature is approached.Comment: 4 pages Latex and 2 postscript figure

The impact of mutation and gene conversion on the local diversification of antigen genes in African trypanosomes

Patterns of genetic diversity in parasite antigen gene families hold important information about their potential to generate antigenic variation within and between hosts. The evolution of such gene families is typically driven by gene duplication, followed by point mutation and gene conversion. There is great interest in estimating the rates of these processes from molecular sequences for understanding the evolution of the pathogen and its significance for infection processes. In this study, a series of models are constructed to investigate hypotheses about the nucleotide diversity patterns between closely related gene sequences from the antigen gene archive of the African trypanosome, the protozoan parasite causative of human sleeping sickness in Equatorial Africa. We use a hidden Markov model approach to identify two scales of diversification: clustering of sequence mismatches, a putative indicator of gene conversion events with other lower-identity donor genes in the archive, and at a sparser scale, isolated mismatches, likely arising from independent point mutations. In addition to quantifying the respective probabilities of occurrence of these two processes, our approach yields estimates for the gene conversion tract length distribution and the average diversity contributed locally by conversion events. Model fitting is conducted using a Bayesian framework. We find that diversifying gene conversion events with lower-identity partners occur at least five times less frequently than point mutations on variant surface glycoprotein (VSG) pairs, and the average imported conversion tract is between 14 and 25 nucleotides long. However, because of the high diversity introduced by gene conversion, the two processes have almost equal impact on the per-nucleotide rate of sequence diversification between VSG subfamily members. We are able to disentangle the most likely locations of point mutations and conversions on each aligned gene pair

Holes in my memories: A qualitative study of men affected by father absence

This qualitative study explored adult men's experiences of father absence. Interviews with 21 men between the ages of 24 and 70 explored narratives of father absence and how the men perceived this influenced their life trajectory. Thematic analysis revealed that these men experienced a range of difficulties and challenges, including episodes of sadness and depression associated with loss and grief for the paternal relationship, self-esteem issues, feelings of anger and rejection, and difficulty forming trusting relationships particularly with other men. This study contributes to understanding mental health issues that can be associated with paternal absence for men. © 2014 Informa Healthcare USA, Inc