Research Opportunities in Nutrition and Metabolism in Space

The objectives of the Life Sciences Research Office (LSRO) study on nutrient requirements for meeting metabolic needs in manned space flights are as follows: review extant knowledge on the subject; identify significant gaps in knowledge; formulate suggestions for possible research; and produce a documented report of the foregoing items that can be used for program planning. In accordance with NASA's request for this study, the report focuses on issues of nutrition and metabolism that relate primarily to the contemplated United States Space Station, secondarily to the Shuttle Program as an orbital test bed for operational studies, and incidentally to scenarios for future long-term space flights. Members of the LSRO ad hoc Working Group on Nutrition and Metabolism were provided with pertinent articles and summaries on the subject. At the meeting of the Working Group, presentations were made by NASA Headquarters program staff on past experiences relative to space-flight nutrition and metabolism, as well as scenarios for future flights. The discussions of the ad hoc Working Group focused on the following: (1) metabolic needs related to work and exercise; (2) nutrients required to meet such needs; (3) food types, management, and records; and (4) nutritional amelioration or prevention of space-related physiological and behavioral changes

In the age of ‘liquid modernity’: self-initiated expatriates in Crete, their multi-generational families and the community

In this paper, we aim to broaden and deepen the current debate on expatriation in business and management discourse, and especially self-initiated expatriation. Following Bauman’s [Liquid Modernity (2000), Cambridge: Polity; Liquid Love, On the Frailty of Human Bonds (2003), Cambridge: Polity] critique of postmodern society and, employing an anthropological lens, we examine work-related expatriation as set within a wider life context. Whereas conventional expatriation research focus is on the workplace, the focus of this study is the wider community. We take a longitudinal approach demonstrating the essential fluid nature of expatriation in general, self-initiated expatriation in particular. We show the importance of multi-generational links as overall critical considerations in effecting decisions to move or stay; we also show how over time, changes in circumstances, career plans and demands of significant others, drive the expatriate agenda. We pay particular attention to nontraditional expatriates and issues of health and disability in the extended family. Finally, we document the importance of the wider family and of the community in the process of adjustment and in engendering a sense of belonging

The Amplitude Mode in the Quantum Phase Model

We derive the collective low energy excitations of the quantum phase model of interacting lattice bosons within the superfluid state using a dynamical variational approach. We recover the well known sound (or Goldstone) mode and derive a gapped (Higgs type) mode that was overlooked in previous studies of the quantum phase model. This mode is relevant to ultracold atoms in a strong optical lattice potential. We predict the signature of the gapped mode in lattice modulation experiments and show how it evolves with increasing interaction strength.Comment: 4 pages, 3 figure

Decay of superfluid currents in a moving system of strongly interacting bosons

We analyze the stability and decay of supercurrents of strongly interacting bosons on optical lattices. At the mean-field level, the system undergoes an irreversible dynamic phase transition, whereby the current decays beyond a critical phase gradient that depends on the interaction strength. At commensurate filling the transition line smoothly interpolates between the classical modulational instability of weakly interacting bosons and the equilibrium Mott transition at zero current. Below the mean-field instability, the current can decay due to quantum and thermal phase slips. We derive asymptotic expressions of the decay rate near the critical current. In a three-dimensional optical lattice this leads to very weak broadening of the transition. In one and two dimensions the broadening leads to significant current decay well below the mean-field critical current. We show that the temperature scale below which quantum phase slips dominate the decay of supercurrents is easily within experimental reach.Accepted manuscrip