7,318 research outputs found
Results of post-test psychological examinations of the crewmen from the 90-day manned test of an advanced regenerative life support system
The following material presents the results of two temporally remote administrations of an identical projective personality assessment device (Rorschach Inkblot) using crew members aboard the 90-day test. The first administration took place during preselection crew psychodiagnostic testing in the period extending from mid-December 1969 through mid-January 1970. Second administration took place in late May and early June, 1971, approximately one year after termination of the test. During the 90-day program duration, the subjects participated in the crew training program, were selected and served as onboard crew during the 90-day test. The testing was undertaken in order to determine the character and extent of change (if any) in basic personality dynamics accompanying or caused by participation in the 90-day test program. Results indicate that significant personality changes occurred in three of the four onboard crew members. A detailed discussion of the results is provided. Objective scores which served as the basis for the discussion are presented in the Appendix
Optimally defined Racah-Casimir operators for su(n) and their eigenvalues for various classes of representations
This paper deals with the striking fact that there is an essentially
canonical path from the -th Lie algebra cohomology cocycle, ,
of a simple compact Lie algebra \g of rank to the definition of its
primitive Casimir operators of order . Thus one obtains a
complete set of Racah-Casimir operators for each \g and nothing
else. The paper then goes on to develop a general formula for the eigenvalue
of each valid for any representation of \g, and thereby
to relate to a suitably defined generalised Dynkin index. The form of
the formula for for is known sufficiently explicitly to make
clear some interesting and important features. For the purposes of
illustration, detailed results are displayed for some classes of representation
of , including all the fundamental ones and the adjoint representation.Comment: Latex, 16 page
Dynamical Symmetries in q-deformed Quantum Mechanics
The dynamical algebra of the q-deformed harmonic oscillator is constructed.
As a result, we find the free deformed Hamiltonian as well as the Hamiltonian
of the deformed oscillator as a complicated, momentum dependent interaction
Hamiltonian in terms of the usual canonical variables. Furthermore we construct
a well-defined algebra SU(1,1) with consistent conjugation properties and
comultiplication. We obtain non lowest weight representations of this algebra.Comment: 19 pages, latex, no figure
The effect of an internet option and single-sided printing format to increase the response rate to a population-based study : a randomized controlled trial
Acknowledgements We would like to thank the Institute of Applied Health Sciences (IAHS) at the University of Aberdeen for funding the PhD studentship of EF. Furthermore, we would like to thank everyone who was involved in the study, including Professor Sir Lewis Ritchie (Director of Public Health, NHS Grampian), John Lemon (University of Aberdeen), Dr. Fiona Garton (University of Aberdeen) and the Aberdeen Service User Group. Lastly, we would like to acknowledge all data entry clerks (Maxx Livingstone, Rory Macfarlane, Georgia Mannion-Krase and Hazel Reilly) and participants of the study.Peer reviewedPublisher PD
The prevalence of fibromyalgia in the general population : A comparison of the American College of Rheumatology 1990, 2010 and modified 2010 classification criteria
Copyright © 2014 American College of Rheumatology. Funded by University of Aberdeen Development TrustPeer reviewedPostprin
Rethinking the Economics of Land and Housing
Why are house prices in many advanced economies rising faster than incomes? Why isn't land and location taught or seen as important in modern economics? What is the relationship between the financial system and land?
In this accessible but provocative guide to the economics of land and housing, the authors reveal how many of the key challenges facing modern economies - including housing crises, financial instability and growing inequalities - are intimately tied to the land economy. Looking at the ways in which discussions of land have been routinely excluded from both housing policy and economic theory, the authors show that in order to tackle these increasingly pressing issues a major rethink by both politicians and economists is required
Real Forms of the Oscillator Quantum Algebra and its Representations
We consider the conditions under which the -oscillator algebra becomes a
Hopf -algebra. In particular, we show that there are at least two real forms
associated with the algebra. Furthermore, through the representations, it is
shown that they are related to with different
conjugations.Comment: 10 pages, Ams-Tex, To be published in Letters in Mathematical physic
Bridging the gap between individual-based and continuum models of growing cell populations
Continuum models for the spatial dynamics of growing cell populations have been widely used to investigate the mechanisms underpinning tissue development and tumour invasion. These models consist of nonlinear partial differential equations that describe the evolution of cellular densities in response to pressure gradients generated by population growth. Little prior work has explored the relation between such continuum models and related single-cell-based models. We present here a simple stochastic individual-based model for the spatial dynamics of multicellular systems whereby cells undergo pressure-driven movement and pressure-dependent proliferation. We show that nonlinear partial differential equations commonly used to model the spatial dynamics of growing cell populations can be formally derived from the branching random walk that underlies our discrete model. Moreover, we carry out a systematic comparison between the individual-based model and its continuum counterparts, both in the case of one single cell population and in the case of multiple cell populations with different biophysical properties. The outcomes of our comparative study demonstrate that the results of computational simulations of the individual-based model faithfully mirror the qualitative and quantitative properties of the solutions to the corresponding nonlinear partial differential equations. Ultimately, these results illustrate how the simple rules governing the dynamics of single cells in our individual-based model can lead to the emergence of complex spatial patterns of population growth observed in continuum models
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