Judgments relative to patterns

Four experiments study relative frequency judgment and recall of sequentially presented items drawn from two distinct categories (e.g., cities, animals). The experiments show that judged frequencies of sequentially encountered stimuli are affected by certain properties of the sequence configuration. We find (a) a first-run effect whereby people overestimate the frequency of a given category when that category is the first repeated category to occur in the sequence and (b) a dissociation between judgments and recall; respondents may judge one event more likely than the other and yet recall more instances of the latter. Judged frequency of categories of items is influenced by the first run - which may reflect the operation of a judgment heuristic. The distribution of recalled individual items does not correspond to the frequency estimates, indicating that participants do not make frequency judgments by sampling their memory for individual items. We propose a simple strategy whereby respondents use the first run as a cue to frequency that accounts for this observation and other context effects on memory and judgment

EDIN design study alternate space shuttle booster replacement concepts. Volume 2: Design simulation results

Historical weight estimating relationships were developed for the liquid rocket booster (LRB) using Saturn technology, and modified as required to support the EDIN05 study. Mission performance was computed using February 1975 shuttle configuration groundrules to allow reasonable comparison of the existing shuttle with the EDIN05 designs. The launch trajectory was constrained to pass through both the RTLS/AOA and main engine cut-off points. Performance analysis was based on a point design trajectory model which optimized initial tilt rate and exo-atmospheric pitch profile. A gravity turn was employed during the boost phase in place of the shuttle angle-of-attack profile. Engine throttling add/or shutdown was used to constrain dynamic pressure and/or longitudinal acceleration where necessary

High Angular Resolution Stellar Imaging with Occultations from the Cassini Spacecraft II: Kronocyclic Tomography

We present an advance in the use of Cassini observations of stellar occultations by the rings of Saturn for stellar studies. Stewart et al. (2013) demonstrated the potential use of such observations for measuring stellar angular diameters. Here, we use these same observations, and tomographic imaging reconstruction techniques, to produce two dimensional images of complex stellar systems. We detail the determination of the basic observational reference frame. A technique for recovering model-independent brightness profiles for data from each occulting edge is discussed, along with the tomographic combination of these profiles to build an image of the source star. Finally we demonstrate the technique with recovered images of the {\alpha} Centauri binary system and the circumstellar environment of the evolved late-type giant star, Mira.Comment: 8 pages, 8 figures, Accepted by MNRA

Domain effects and financial risk attitudes

We investigated whether financial risk preferences are dependent on the financial domain (i.e., the context) in which the risky choice options are presented. Previous studies have demonstrated that risk attitudes change when gambles are framed as gains, losses, or as insurance. Our study explores this directly by offering choices between identical gambles, framed in terms of seven financial domains. Three factors were extracted, explaining 68.6% of the variance: Factor 1 (Positive)—opportunity to win, pension provision, and job salary change; Factor 2 (Positive-Complex)—investments and mortgage buying; Factor 3 (Negative)—possibility of loss and insurance. Inspection of the solution revealed context effects on risk perceptions across the seven scenarios. We also found that the commonly accepted assumption that women are more risk averse cannot be confirmed with the context structure suggested in this research; however, it is acknowledged that in the students’ population the variance across genders might be considerably less. These results suggest that our financial risk attitude measures may be tapping into a stable aspect of “context dependence” of relevance to real-world decision making

Judgments Relative to Patterns: How Temporal Sequence Patterns Affect Judgments and Memory

Six experiments studied relative frequency judgment and recall of sequentially presented items drawn from 2 distinct categories (i.e., city and animal). The experiments show that judged frequencies of categories of sequentially encountered stimuli are affected by certain properties of the sequence configuration. We found (a) a first-run effect whereby people overestimated the frequency of a given category when that category was the first repeated category to occur in the sequence and (b) a dissociation between judgments and recall; respondents may judge 1 event more likely than the other and yet recall more instances of the latter. Specifically, the distribution of recalled items does not correspond to the frequency estimates for the event categories, indicating that participants do not make frequency judgments by sampling their memory for individual items as implied by other accounts such as the availability heuristic (Tversky & Kahneman, 1973) and the availability process model (Hastie & Park, 1986). We interpret these findings as reflecting the operation of a judgment heuristic sensitive to sequential patterns and offer an account for the relationship between memory and judged frequencies of sequentially encountered stimuli

Stabilising the Blue Phases

We present an investigation of the phase diagram of cholesteric liquid crystals within the framework of Landau - de Gennes theory. The free energy is modified to incorporate all three Frank elastic constants and to allow for a temperature dependent pitch in the cholesteric phase. It is found that the region of stability of the cubic blue phases depends significantly on the value of the elastic constants, being reduced when the bend elastic constant is larger than splay and when twist is smaller than the other two. Most dramatically we find a large increase in the region of stability of blue phase I, and a qualitative change in the phase diagram, in a system where the cholesteric phase displays helix inversion.Comment: 15 pages, 6 figure

Ab-initio investigation of phonon dispersion and anomalies in palladium

In recent years, palladium has proven to be a crucial component for devices ranging from nanotube field effect transistors to advanced hydrogen storage devices. In this work, I examine the phonon dispersion of fcc Pd using first principle calculations based on density functional perturbation theory. While several groups in the past have studied the acoustic properties of palladium, this is the first study to reproduce the phonon dispersion and associated anomaly with high accuracy and no adjustable parameters. In particular, I focus on the Kohn anomaly in the [110] direction.Comment: 19 pages, preprint format, 7 figures, added new figures and discussio

Biomechanical analysis of walking gait when simulating the use of an Ilizarov external fixator

The Ilizarov frame is an external fixation device, primarily used for the treatment of complex fractures. The authors postulate that the size and weight of the frame may lead to biomechanical adaptations to gait, independent to any injury. Temporospatial characteristics, kinetics and kinematics were assessed when simulating the use of an Ilizarov frame. Fifteen healthy participants performed walking trials, with and without the simulated frame. Significant changes to temporospatial characteristics were identified, with a decreased mean walking speed (with: 1.24 m s⁻¹; without: 1.29 m s⁻¹) and increased mean step width (with: 0.14 m; without: 0.11 m). The push-off phase of gait differed significantly between test conditions with mean increases in ankle dorsiflexion angles (with: 90.4°; without: 89.0°) and extension moments (proportional to body weight or P BWT) at the knee and ankle (knee with: 0.8 P BWT·m; without: 0.7 P BWT·m; ankle with: 1.6 P BWT·m; without: 1.6 P BWT·m). Although changes were small and likely to be clinically insignificant, the size and weight of the frame led to adaptations which may be magnified for patient groups with associated injury and pain at the lower limb. Results provide an argument for the potential redesign of the frame