Infrared Astronomical Satellite (IRAS) Scientific Data Analysis System

The Jet Propulsion Laboratory's Scientific Data Analysis System will process Infrared Astronomical Satellite data and produce a catalog of perhaps a million infrared sources in the sky, as well as other vital information for astronomical research

Near-encounter geometry generation

Generation of near encounter spacecraft-target planet celestial geometry using two body trajectory computerized simulatio

Kinematic differences between defended and undefended shots in netball

Successful shooting in netball depends not only on achieving the correct angle, velocity and height of release, but also on how well the shooter can adjust these factors when faced with a defender. However, few studies, if any, have analysed the difference between shots taken with a defender present and those without (usually due to a penalty against the defender). The aim of the study was to examine the difference in kinematic variables between defended and undefended shots during netball games. The study was approved by the university’s ethics committee and informed consent was given by eight elite netballers (age mean 22.1, s=2.3 years; stature 1.81, s=.08 m; mass 69.0, s=8.7 kg). Each participant was filmed playing in a Netball Superleague game during the 2007/2008 season. Two stationary Canon DM-XL1 digital cameras were placed on a balcony overlooking the playing area, so as not to interfere with the players or spectators. The sampling rate was 50 Hz, and the shutter speed 1/500 s. Two successful shots per player were digitised and analysed using SIMI Motion (Munich) and filtered using a Butterworth low-pass 2nd order filter. The two shots consisted of one successful defended shot, and one successful undefended shot (due to a penalty awarded against the opposing team’s defender). Statistical analysis consisted of dependent t-tests. The height of release was higher for defended shots (2.16 m, s=0.28) than in undefended shots (1.93 m, s=0.04). This was caused partially due to greater elbow extension during the shooting action. The maximum elbow angle for defended shots was 138° (s=25) and for undefended shots 108° (s=23). The significant difference found between these values (P=0.049) was the only one found between the two shooting conditions. The angle of release at the shoulder was higher for defended shots (141°, s= 22) compared to undefended (133°, s=7), as was the vertical velocity of the wrist at release (0.54 m s -1, s=0.31 and 0.43 m s -1, s=0.12 respectively). Several differences were found between shooting with and without a defender, although only one was found to be significant. Nonetheless, it was clear that shooting with a defender present required a greater height of release, and larger shooting arm joint angles. It is important for netball players and coaches to shoot with defenders present during training in order to practice the style of shooting required during a game

Pedestrian demand modelling of large cities: an applied example from London

This paper introduces a methodology for the development of city wide pedestrian demand models and shows its application to London. The approach used for modelling is Multiple Regression Analysis of independent variables against the dependent variable of observed pedestrian flows. The test samples were from manual observation studies of average total pedestrian flow per hour on 237 sample sites. The model will provide predicted flow values for all 7,526 street segments in the 25 square kilometres of Central London. It has been independently validated by Transport for London and is being tested against further observation data. The longer term aim is to extend the model to the entire greater London area and to incorporate additional policy levers for use as a transport planning and evaluation tool

A periodic elastic medium in which periodicity is relevant

We analyze, in both (1+1)- and (2+1)- dimensions, a periodic elastic medium in which the periodicity is such that at long distances the behavior is always in the random-substrate universality class. This contrasts with the models with an additive periodic potential in which, according to the field theoretic analysis of Bouchaud and Georges and more recently of Emig and Nattermann, the random manifold class dominates at long distances in (1+1)- and (2+1)-dimensions. The models we use are random-bond Ising interfaces in hypercubic lattices. The exchange constants are random in a slab of size $L^{d-1} \times \lambda$ and these coupling constants are periodically repeated along either {10} or {11} (in (1+1)-dimensions) and {100} or {111} (in (2+1)-dimensions). Exact ground-state calculations confirm scaling arguments which predict that the surface roughness $w$ behaves as: $w \sim L^{2/3}, L \ll L_c$ and $w \sim L^{1/2}, L \gg L_c$, with $L_c \sim \lambda^{3/2}$ in $(1+1)$-dimensions and; $w \sim L^{0.42}, L \ll L_c$ and $w \sim \ln(L), L \gg L_c$, with $L_c \sim \lambda^{2.38}$ in $(2+1)$-dimensions.Comment: Submitted to Phys. Rev.

Intermittence and roughening of periodic elastic media

We analyze intermittence and roughening of an elastic interface or domain wall pinned in a periodic potential, in the presence of random-bond disorder in (1+1) and (2+1) dimensions. Though the ensemble average behavior is smooth, the typical behavior of a large sample is intermittent, and does not self-average to a smooth behavior. Instead, large fluctuations occur in the mean location of the interface and the onset of interface roughening is via an extensive fluctuation which leads to a jump in the roughness of order $\lambda$, the period of the potential. Analytical arguments based on extreme statistics are given for the number of the minima of the periodicity visited by the interface and for the roughening cross-over, which is confirmed by extensive exact ground state calculations.Comment: Accepted for publication in Phys. Rev.

Acquisitive prescription and fundamental rights

Various seventeenth-century parliamentarians resorted to the concept of acquisitive prescription when denouncing irresponsible use of the royal prerogative. Often, the concept was invoked to convey nothing more than that a custom had existed since time immemorial. But sometimes the concept was being used in its legal sense: to denote the acquisition of a right (as if someone with the authority to grant that right had done so) by virtue of some instance of long and uninterrupted enjoyment over a period of time. This paper considers the application of acquisitive prescription, a doctrine rooted in the medieval law of land obligations, in Stuart constitutional discourse