A space station onboard scheduling assistant

One of the goals for the Space Station is to achieve greater autonomy, and have less reliance on ground commanding than previous space missions. This means that the crew will have to take an active role in scheduling and rescheduling their activities onboard, perhaps working from preliminary schedules generated on the ground. Scheduling is a time intensive task, whether performed manually or automatically, so the best approach to solving onboard scheduling problems may involve crew members working with an interactive software scheduling package. A project is described which investigates a system that uses knowledge based techniques for the rescheduling of experiments within the Materials Technology Laboratory of the Space Station. Particular attention is paid to: (1) methods for rapid response rescheduling to accommodate unplanned changes in resource availability, (2) the nature of the interface to the crew, (3) the representation of the many types of data within the knowledge base, and (4) the possibility of applying rule-based and constraint-based reasoning methods to onboard activity scheduling

Oscillatory decay of a two-component Bose-Einstein condensate

We study the decay of a two-component Bose-Einstein condensate with negative effective interaction energy. With a decreasing atom number due to losses, the atom-atom interaction becomes less important and the system undergoes a transition from a bistable Josephson regime to the monostable Rabi regime, displaying oscillations in phase and number. We study the equations of motion and derive an analytical expression for the oscillation amplitude. A quantum trajectory simulation reveals that the classical description fails for low emission rates, as expected from analytical considerations. Observation of the proposed effect will provide evidence for negative effective interaction.Comment: 4 pages, 3 figue

Spatial patterns in the evolution of Cenozoic dynamic topography and its influence on the Antarctic continent

Our knowledge of dynamic topography in Antarctica remains in an infancy stage compared to other continents. We assess the space-time variability in dynamic topography in Antarctica by analysing grids of global dynamic topography in the Cenozoic (and late Cretaceous) based on the tomographic model S40RTS. Our model reveals that the Gamburtsev Province and Dronning Maud Land, two of the major nucleation sites for the East Antarctic Ice Sheet (EAIS) were ~500 m higher 60 Ma ago. The increased elevation may have facilitated ephemeral ice cap development in the early Cenozoic. Between ca 25 and 50 Ma the northern Wilkes Subglacial Basin was ca 200 m higher than today and a major increase in regional elevation (>600 m) occurred over the last 20-15 Ma over the northern and southern Victoria Land in the Transantarctic Mountains (TAM). The most prominent signal is observed over the Ross Sea Rift (RSR) where predicted Neogene dynamic topography exceeds 1,000 m. The flow of warm mantle from the West Antarctic Rift System (WARS)may have driven these dynamic topography effects over the TAM and RSR. However, we found that these effects are comparatively less significant over the Marie Byrd Land Dome and the interior of the WARS. If these contrasting dynamic topography effects are included, then the predicted elevations of the Ross Sea Embayment ca 20 Ma ago are more similar to the interior of the WARS, with significant implications for the early development of the West Antarctic Ice Sheet

Maternal employment and overweight children

This paper seeks to determine whether a causal relationship exists between maternal employment and childhood overweight. We use matched mother/child data from the National Longitudinal Survey of Youth and employ econometric techniques to control for observable and unobservable differences across individuals and families that may influence both children's weight and their mothers' work patterns. Our results indicate that a child is more likely to be overweight if his/her mother worked more hours per week over the child's life. Analyses by subgroups show that it is higher socioeconomic status mothers whose work intensity is particularly deleterious for their children's overweight status.Employment (Economic theory) ; Overweight children

Maternal Employment and Overweight Children

This paper investigates whether children are more or less likely to be overweight if their mothers work. The prevalence of both overweight children and working mothers has risen dramatically over the past few decades, although these parallel trends may be coincidental. The goal of this paper is to help determine whether a causal relationship exists between maternal employment and childhood overweight. To accomplish this, we mainly utilize matched mother/child data from the National Longitudinal Survey of Youth and employ three main econometric techniques, probit models, sibling difference models, and instrumental variables models in this analysis. Our results indicate that a child is more likely to be overweight if his/her mother worked more intensively (in the form of greater hours per week) over the child's life. This effect is particularly evident for children of white mothers, of mothers with more education, and of mothers with a high income level. Applying our estimates to the trend towards greater maternal employment indicates that the increased hours worked per week among mothers between 1975 and 1999 led to about a 0.4 to 0.7 percentage point increase in overweight children, which represents a relatively small share of the overall increase.

Massive liquid Ar and Xe detectors for direct Dark Matter searches

A novel experiment for direct searches of the Dark Matter with liquid argon double-phase chamber with a mass of liquid Ar up to several hundred tons is proposed. To suppress the b-, g- and n0- backgrounds, the comparison of scintillation and ionization signals for every event is suggested. The addition in liquid Ar of photosensitive Ge(CH3)4 or C2H4 and suppression of triplet component of scintillation signals ensures the detection of scintillation signals with high efficiency and provides a complete suppression of the electron background. For the detection of photoelectrons and ionization electrons, highly stable and reliable GEM detectors must be used.Comment: 8 pages, 2 figures, 1 tabl

Withering Fruits: Vegetable Matter Decay and Fungus Growth

We propose a parametrised method for recreating drying and decaying vegetable matter from the fruits category, taking into account the biological characteristics of the decaying fruit. The simulation addresses three main phenomena: mould propagation, volume shrinking and fungus growth on the fruit's surface. The spread of decay is achieved using a Reaction-Diffusion method, a Finite Element Method is used for shrinking and wrinkling of the fruit shell, while the spread of the fruit's fungal infection is described by a Diffusion Limited Aggregation algorithm. We extend existing fruit decay approaches, improving the shrinking behaviour of decaying fruits and adding independent fungal growth. Our approach integrates a user interface for artist directability and fine control of the simulation parameters

Magnetic Instability in Strongly Correlated Superconductors

Recently a new phenomenological Hamiltonian has been proposed to describe the superconducting cuprates. This so-called Gossamer Hamiltonian is an apt model for a superconductor with strong on-site Coulomb repulsion betweenthe electrons. It is shown that as one approaches half-filling the Gossamer superconductor, and hence the superconducting state, with strong repulsion is unstable toward an antiferromagnetic insulator an can undergo a quantum phase transition to such an insulator if one increases the on-site Coulomb repulsion