The librational dynamics of satellites

Librational dynamics of satellite

Archetypal analysis of galaxy spectra

Archetypal analysis represents each individual member of a set of data vectors as a mixture (a constrained linear combination) of the pure types or archetypes of the data set. The archetypes are themselves required to be mixtures of the data vectors. Archetypal analysis may be particularly useful in analysing data sets comprising galaxy spectra, since each spectrum is, presumably, a superposition of the emission from the various stellar populations, nebular emissions and nuclear activity making up that galaxy, and each of these emission sources corresponds to a potential archetype of the entire data set. We demonstrate archetypal analysis using sets of composite synthetic galaxy spectra, showing that the method promises to be an effective and efficient way to classify spectra. We show that archetypal analysis is robust in the presence of various types of noise.Comment: 6 pages, 5 figures, 1 style-file. Accepted for publication by MNRA

Optomechanically induced transparency and cooling in thermally stable diamond microcavities

Diamond cavity optomechanical devices hold great promise for quantum technology based on coherent coupling between photons, phonons and spins. These devices benefit from the exceptional physical properties of diamond, including its low mechanical dissipation and optical absorption. However the nanoscale dimensions and mechanical isolation of these devices can make them susceptible to thermo-optic instability when operating at the high intracavity field strengths needed to realize coherent photon--phonon coupling. In this work, we overcome these effects through engineering of the device geometry, enabling operation with large photon numbers in a previously thermally unstable regime of red-detuning. We demonstrate optomechanically induced transparency with cooperativity > 1 and normal mode cooling from 300 K to 60 K, and predict that these device will enable coherent optomechanical manipulation of diamond spin systems

Optical frequency tripling with improved suppression and sideband selection

Journal Article, Impact factor:3.749A novel optical dispersion tolerant millimetre-wave radio-over-fibre system using optical frequency tripling technique with enhanced and selectable sideband suppression is demonstrated. The implementation utilises cascaded optical modulators to achieve either an optical single sideband (OSSB) or double sideband-suppressed carrier (DSB-SC) signal with high sideband suppression. Our analysis and simulation results indicate that the achievable suppression ratio of this configuration is only limited by other system factors such as optical noise and drifting of the operational conditions. The OSSB transmission system performance is assessed experimentally by the transport of 4 WiMax channels modulating a 10 GHz optical upconverted RF carrier as well as for optical frequency doubling and tripling. The 10 GHz and tripled carrier at 30 GHz are dispersion tolerant resulting both in an average relative constellation error (RCE) of -28.7 dB after 40 km of fibre. (C)2011 Optical Society of AmericaFundação para a Ciência e Tecnologi

Microstructure and mechanical properties of bulk yttria-partially-stabilized zirconia

A commercially available bulk 4.5 mole percent yttria-(Y2O3) partially stabilized zirconia (PSZ) was studied by light microscopy, X-ray analysis, microhardness measurement, and fracture toughness testing. The growth of the precipitates and the phase transformations were studied as a function of aging in air at 1500 C. Aging curves were constructed for both the as received and the solution annealed and quenched materials; the curves showed hardness peaks at 1397 and 1517 Kg/sq mm respectively. The rectangular plate shaped tetragonal precipitates were found to have a 110 habit plane. A total of twelve different types of tetragonal precipitates were found. Grinding of the Y2O3 PSZ into powder did not cause a significant amount of metastable tetragonal precipitates to transform into the monoclinc phase, thus indicating that transformation toughening is not a significant mechanism for the material

A human factors methodology for real-time support applications

A general approach to the human factors (HF) analysis of new or existing projects at NASA/Goddard is delineated. Because the methodology evolved from HF evaluations of the Mission Planning Terminal (MPT) and the Earth Radiation Budget Satellite Mission Operations Room (ERBS MOR), it is directed specifically to the HF analysis of real-time support applications. Major topics included for discussion are the process of establishing a working relationship between the Human Factors Group (HFG) and the project, orientation of HF analysts to the project, human factors analysis and review, and coordination with major cycles of system development. Sub-topics include specific areas for analysis and appropriate HF tools. Management support functions are outlined. References provide a guide to sources of further information

The effect of a short course in cognitive and behavioural therapy (CBT) on knowledge acquisition in non-specialist CBT practitioners

This document is the Accepted Manuscript version of a published work that appeared in final form in Advances in Psychology Research. To access the final edited and published work see https://www.novapublishers.com.In this study, we investigate the effects of training on knowledge acquisition in Cognitive Behavioural Therapy (CBT). Knowledge acquisition is assessed through the Cognitive Behavioural Therapy Knowledge Questionnaire (CBT-KQ; Myles, Latham, Ricketts, 2002). The CBT-KQ contains 26 multiple-choice questions from five conceptual topics: general CBT issues, theoretical underpinnings of behavioural approaches, theoretical underpinnings of cognitive approaches, practice of behavioural therapy, and practice of cognitive therapy. Thirty eight students attended weekly 3 hour sessions and were tested at weeks 1 and 15 in a before and after study. Improvements in the CBT-KQ were modest but showed significant changes in three conceptual topics; general CBT issues, theoretical underpinnings of cognitive approaches and practice of cognitive therapy. These findings may have important implications for structuring CBT training, so that both the cognitive and behavioural components are shown in the knowledge acquisition and practice applications. Recent evidence suggests that the behavioural components of treatment for some conditions, such as depression, may be more important than the cognitive components. In addition, recent evidence indicates that the behavioural components might be more suitable for delivery by non-specialist CBT practitioners

Autobiographical memory response to a negative mood in those with/without a history of depression

Research ArticleThis document is the final version of a published work that appeared in Studia Psychologica here http://psychologia.sav.sk/sp/index.php?id=home.In this study, we investigated the accessibility of overgeneral autobiographical memories (OGM) and specific memories by observing the effects of induced negative mood state on the characteristics of memory recall in those with and without a previous history of a depression. The Sentence Completion for Events from the Past Test (SCEPT) was used to assess OGM. The effects of previous history of depression (without history or with previous history of depression) and self-reported mood (pre or post negative mood induction) on autobiographical recall was shown in a mixed factor design. A significant interaction was observed between time and group in their effects on general memories (F(1, 32) = 5.06, p = .03) and specific memory (F(1, 32) = 4.88, p = .03), such that the previous history of depression group experienced a larger increase in general memory and a larger reduction in specific memory from pre to post manipulation

Phenomenological characteristics of autobiographical memories: responsiveness to an induced negative mood state in those with and without a previous history of depression.

This document is the Accepted Manuscript version of a published work that appeared in final form in Advances in Cognitive Psychology. To access the final edited and published work see http://dx.doi.org/10.5709/acp-0190-8.In this study we investigated the relative accessibility of phenomenological characteristics in autobiographical memories of 104 students with and without a previous history of a depression. Participants recalled personal events that were elicited with cue words and then asked to rate these personal events for a number of phenomenological characteristics. The characteristics were typicality, rumination, valence, importance of others, expectancy, desirability, and personal importance. The effects of previous history of depression (without history or with previous history of depression) and self-reported mood (pre- and post-negative mood induction) on autobiographical recall was examined by employing a mixed factor design. Self-reported mood was measured as a manipulation check, before and after Mood Induction Procedure. Typicality, rumination and personal importance showed significant interaction effects in those with a history of depression. Ordinal regression supported the finding that those with a history of depression had a higher chance of typicality and personal importance than those without a history of depression. The results indicate that recall of autobiographical characteristics is in part dependent on induced negative mood state and on previous history of depression. The findings may prompt future research into targeted interventions that reduce individual tendencies for heightened cognitive reactivity in negative mood states for those with a history of depression

The responsiveness of negative cognitive content to an induced negative mood state in those with and without a previous history of depression in a student sample

This study investigates the responsiveness of cognitions to an induced negative mood state in those with and without a previous history of depression in a non-clinical student sample (n = 101). The Automatic Thought Questionnaire (ATQ-30) was used to observe the negative cognitive content. The negative mood state was induced in small groups utilising the Velten Negative Mood Induction Procedure (VNMIP). Self-reported mood was measured using the University of Wales Institute of Science and Technology (UWIST) Mood Adjective Checklist (UMACL) before and after VNMIP. The effects of previous history of depression (without history or with previous history of depression) and self-reported mood (pre or post negative mood induction) on cognitive content was shown in a 2 x 2 ANOVA with time (pre-test vs. post-test) as a within subjects factor and history of depression (with a history of depression vs. without a history of depression) as a between subjects factor. The results indicate no significant interaction between time and group in their effects on negative cognitive content. Also, there was no significant main effect for time on negative cognitive content. However, there was a significant main effect for previous history of depression on negative cognitive content. Findings are discussed on the basis of the literature and possible applications for practice