An investigation of correlation between pilot scanning behavior and workload using stepwise regression analysis

An electro-optical device called an oculometer which tracks a subject's lookpoint as a time function has been used to collect data in a real-time simulation study of instrument landing system (ILS) approaches. The data describing the scanning behavior of a pilot during the instrument approaches have been analyzed by use of a stepwise regression analysis technique. A statistically significant correlation between pilot workload, as indicated by pilot ratings, and scanning behavior has been established. In addition, it was demonstrated that parameters derived from the scanning behavior data can be combined in a mathematical equation to provide a good representation of pilot workload

Users guide: The LaRC human-operator-simulator-based pilot model

A Human Operator Simulator (HOS) based pilot model has been developed for use at NASA LaRC for analysis of flight management problems. The model is currently configured to simulate piloted flight of an advanced transport airplane. The generic HOS operator and machine model was originally developed under U.S. Navy sponsorship by Analytics, Inc. and through a contract with LaRC was configured to represent a pilot flying a transport airplane. A version of the HOS program runs in batch mode on LaRC's (60-bit-word) central computer system. This document provides a guide for using the program and describes in some detail the assortment of files used during its operation

Models of human operators in vision dependent tasks

Descriptive overviews of some existing models and techniques of modelling the human operator are presented

Evaluating Multiple Arthropod Taxa as Indicators of Invertebrate Diversity in Old Fields

Biodiversity, often quantified by species richness, is commonly used to evaluate and monitor the health of ecosystems and as a tool for conservation planning. The use of one or more focal taxa as surrogates or indicators of larger taxonomic diversity can greatly expedite the process of biodiversity measurement. This is especially true when studying diverse and abundant invertebrate fauna. Before indicator taxa are employed, however, research into their suitability as indicators of greater taxonomic diversity in an area is needed. We sampled invertebrate diversity in old fields in southern Michigan using pitfall trapping and morphospecies designations after identification to order or family. Correlation analysis was used to assess species richness relationships between focal arthropod taxa and general invertebrate diversity. Relationships were assessed at two fine spatial scales: within sampling patches, and locally across four sampling patches. Cumulative richness of all assessed taxa increased proportionately with cumulative invertebrate richness as sampling intensity increased within patches. At the among-patch scale, we tentatively identified Hemiptera and Coleoptera as effective indicator taxa of greater invertebrate richness. Although Hymenoptera, Araneae and Diptera exhibited high species richness, their total richness within patches was not associated with overall invertebrate richness among patches. Increased sampling throughout the active season and across a greater number of habitat patches should be conducted before adopting Hemiptera and Coleoptera as definitive indicators of general invertebrate richness in the Great Lakes region. Multiple sampling techniques, in addition to pitfall trapping, should also be added to overcome capture biases associated with each technique

Linking Protection with the Distribution of Grouper and Habitat Quality in Seychelles

Marine protected areas can be designated for a number of reasons, but exactly how they provide benefits is only recently being understood. We assessed the effect of protection on the size and distribution of six common species of grouper in a coral reef ecosystem. Data on live coral cover, coral genus diversity, and coral colony structure type were also compared to give an indication of reef quality between sites. A significant interaction was found for Aethaloperca rogaa and, Cephalopholis nigripinni, indicating that protected areas held greater numbers of smaller and median sized fish of these species than unprotected areas. Similar but nonsignificant trends were found for Cephalopholis miniata and Cephalopholis argus.For Anyperodon leucogrammicus,MPAs held significantly more fish than unprotected sites,but as the increase was equal between size categories there was no interaction.The last species Epinephelus fasciatus, which was one of the smallest species, had no significant interaction, similar mean counts between protected and unprotected areas, and no obvious strong favouritism for particular sites with values indicating better reef quality, indicating intraspecies competition. The results of this study indicate that while the MPAs in this study are likely too small to benefit large groupers, the improvements to habitat quality have indirect benefits to groupers, especially at their earlier life stages

Influence of Duration of Homograft on Humoral Responses in Man

Elevated titers of natural antibodies have been demonstrated in the sera of patients following transplantation. These humoral responses were thought to be associated with rejection. This concept was challenged by investigators whose studies associated these responses with infection or with injection of heterologous serum. Nevertheless, the possible prognostic significance of these relatively simple tests has continued to evoke interest. This study was undertaken to compare the humoral responses in three different groups of patients with organ transplants in order to evaluate the influence of duration of the homograft and the attendant immunosuppression

Offering disinclined people the choice between different screening appointments: a randomised online survey

Objectives: An invitation to cancer screening with a single (fixed) appointment time has been shown to be a more effective way at increasing uptake compared with an invitation with an open (unscheduled) appointment. The present study tested whether offering more than one fixed appointment could further enhance this effect or be detrimental to people’s intention. / Design: Experimental online hypothetical vignette survey. / Methods: 1,908 respondents who stated that they did not intend to participate in Bowel Scope Screening (BSS) were offered either one, two, four or six hypothetical fixed BSS appointments (all of which covered the same time of day to control for individual preferences). / Results: Participants who were given more than one appointment to choose from were less likely to intend to book an appointment despite multiple appointments being perceived as more convenient. / Conclusions: These results suggest that when it comes to offering people appointments for cancer screening, less (choice) is more, at least if alternatives fail to serve an inherent preference

New way to achieve chaotic synchronization in spatially extended systems

We study the spatio-temporal behavior of simple coupled map lattices with periodic boundary conditions. The local dynamics is governed by two maps, namely, the sine circle map and the logistic map respectively. It is found that even though the spatial behavior is irregular for the regularly coupled (nearest neighbor coupling) system, the spatially synchronized (chaotic synchronization) as well as periodic solution may be obtained by the introduction of three long range couplings at the cost of three nearest neighbor couplings.Comment: 5 pages (revtex), 7 figures (eps, included

Pattern Formation on Trees

Networks having the geometry and the connectivity of trees are considered as the spatial support of spatiotemporal dynamical processes. A tree is characterized by two parameters: its ramification and its depth. The local dynamics at the nodes of a tree is described by a nonlinear map, given rise to a coupled map lattice system. The coupling is expressed by a matrix whose eigenvectors constitute a basis on which spatial patterns on trees can be expressed by linear combination. The spectrum of eigenvalues of the coupling matrix exhibit a nonuniform distribution which manifest itself in the bifurcation structure of the spatially synchronized modes. These models may describe reaction-diffusion processes and several other phenomena occurring on heterogeneous media with hierarchical structure.Comment: Submitted to Phys. Rev. E, 15 pages, 9 fig

Childhood abuse and eating psychopathology: the mediating role of core beliefs

This study aimed to investigate the mediating role of early maladaptive schemas (core beliefs) in the relationship between childhood abuse and eating psychopathology. Three self-report questionnaires assessing experiences of childhood abuse, eating psychopathology, and levels of maladaptive schemas were administered to 118 female university students. Emotional abuse predicted drive for thinness, whereas sexual abuse predicted symptoms of bulimia nervosa (BN). Mistrust and abuse beliefs were found to fully mediate relationships between childhood abuse and drive for thinness and bulimia scales. Abandonment beliefs were also shown to be partial mediators of the relationship between sexual abuse and symptoms of BN. In a sample of nonclinical women, beliefs pertaining to abandonment and mistrust or abuse appeared to be important in the explanation of the relationship between recollections of childhood abuse and adult eating disorder symptoms