Mapping the optical absorption of a substrate-transferred crystalline AlGaAs coating at 1.5 µm

The sensitivity of 2nd and 3rd generations of interferometric gravitational wave detectors will be limited by thermal noise of the test-mass mirrors and highly reflective coatings. Recently developed crystalline coatings show a promising thermal noise reduction compared to presently used amorphous coatings. However, stringent requirements apply to the optical properties of the coatings as well. We have mapped the optical absorption of a crystalline AlGaAs coating which is optimized for high reflectivity for a wavelength of 1064nm. The absorption was measured at 1550nm where the coating stack transmits approximately 70% of the laser light. The measured absorption was lower than (30.2 +/- 11.1)ppm which is equivalent to (3.6 +/- 1.3)ppm for a coating stack that is highly reflective at 1530nm. While this is a very promising low absorption result for alternative low--loss coating materials, further work will be necessary to reach the requirements of <1ppm for future gravitational wave detectors. Jessica Steinlechner, Iain W Martin, Angus Bell, Garrett Cole, Jim Hough, Steven Penn, Sheila Rowan, Sebastian Steinlechne

The fiction of Nathalie Sarraute : A study of her work from "Tropismes" to "Vous les entendez?"

This thesis is a critical study of the fiction of Nathalie Sarraute. We concentrate on her fiction, as representing the backbone of her creative endeavour, while making reference to her critical essays and her plays where these contribute to a better understanding of the novels, We give particular credit to, and draw extensively upon, those comments on her own work which Nathalie Sarraute has made at various moments and in various contexts, some of them to us personally, We emphasize the personal elements in Nathalie Sarraute's work: her sensitive awareness of tropisms and her view of human psychology have their sources in childhood experience, and her odyssey as a writer, from early hesitations and self-doubt to the later experience of success, finds expression through the preoccupations of each successive novel. Equally, however, we seek to emphasize Nathalie Sarraute's position within an established tradition and her debt to early modernism. Past utterances, as well as her present sense of alienation from the nouveau nouveau roman, whose ranks several of her colleagues from the 1950s have now joined, make her real allegiances clear. Our introduction situates this study in relation to previous Sarraute criticism and states its particular intentions. Nathalie Sarraute's subject-matter in all her novels is seen to be two-fold, to relate on the one hand to human psychology, on the other to art. A first chapter exeresses this subject-matter in greater detail, underlining thereby the extraordinary coherence of Nathalie Sarraute's fictional world. Attention here is concentrated on her vision of the human psyche, which changes little from work to work but which finds increasingly polished and confident expression. Some similarities to contemporary psychological theory are explored. The coherence of Nathalie Sarraute's 'work is also to be understood in terms of a continuing development and it is in such a context that the aesthetic themes are best explored. We aim, moreover, to examine each work as an independent artefact as well as one facet of a unified vision or as a link in a chain of development. In the main body of our thesis, therefore, we proceed in chronological fashion, work by work. Tropismes is seen as a remarkable first work, in which characteristic content and mode of expression are already well-developed. In the works which follow Tropismes, Nathalie Sarraute is primarily concerned with the novel tradition and particularly with the concept of character. Her self-doubt reflects the characteristic uncertainties of, the twentieth-century writer. Portrait d'un inconnu is a highly self-conscious work which explicitly contrasts itself with the greatest of its nineteenth-century predecessors; its narrator is a would-be novelist and his efforts to grapple with character provide the novel with its structure. Martereau takes up where Portrait leaves off and completes the demolition of the traditional 'character' of the realist novel. It is close to Portrait in its use of a narrator-figure as mediator between the novel's subject matter and its readers yet it moves towards Le Planetarium by integrating this figure far more thoroughly into the action of the novel, with Le Planetarium, Nathalie Sarraute no longer needs a defence against the world, an alibi in the shape of a neurotic narrator: here the central theme is the similarity of all the characters at this level of mental activity and all of them are observed from within. Le Planetarium is, then, the culmination of themes with which the earlier novels were concerned; it is also the point of departure for new developments. The concern with the novel widens to include other art objects and the relation of the writer to his environment is seen in a new light. Les Fruits d'or centres on a novel's relation with its public and explores the true nature of aesthetic experience, while revealing as spurious much of what passes for it. Entre la vie et la mort enters the consciousness of the writer once more, describes his experience of the creative process and examines his relationships with the outside world; external image and private reality are juxtaposed and their interrelation explored. Vous les entendez? questions, by means of a tiny incident and the picture of a family relationship which emerges from it, the validity of traditional views of art. The challenge represented by radical forms of modernism is recognized. We refer throughout to other writers whose work presents links, or interesting similarities, with that of Nathalie Sarraute. We end our study with a chapter which outlines Nathalie Sarraute's debt to a number of novelists and redefines her position within a tradition of twentieth-century fiction. Her work represents, we conclude, a development of, rather than a complete break with, previous fictional form. The theory of fiction which could best account for her work would be one which occupied a middle position between the extremes of mimesis and autonomy

Anomalous optical surface absorption in nominally pure silicon samples at 1550 nm

The announcement of the direct detection of Gravitational Waves (GW) by the LIGO and Virgo collaboration in February 2016 has removed any uncertainty around the possibility of GW astronomy. It has demonstrated that future detectors with sensitivities ten times greater than the Advanced LIGO detectors would see thousands of events per year. Many proposals for such future interferometric GW detectors assume the use of silicon test masses. Silicon has low mechanical loss at low temperatures, which leads to low displacement noise for a suspended interferometer mirror. In addition to the low mechanical loss, it is a requirement that the test masses have a low optical loss. Measurements at 1550 nm have indicated that material with a low enough bulk absorption is available; however there have been suggestions that this low absorption material has a surface absorption of > 100 ppm which could preclude its use in future cryogenic detectors. We show in this paper that this surface loss is not intrinsic but is likely to be a result of particular polishing techniques and can be removed or avoided by the correct polishing procedure. This is an important step towards high gravitational wave detection rates in silicon based instruments

Effect of stress and temperature on the optical properties of silicon nitride membranes at 1550 nm

Future gravitational-wave detectors operated at cryogenic temperatures are expected to be limited by thermal noise of the highly reflective mirror coatings. Silicon nitride is an interesting material for such coatings as it shows very low mechanical loss, a property related to low thermal noise, which is known to further decrease under stress. Low optical absorption is also required to maintain the low mirror temperature. Here, we investigate the effect of stress on the optical properties at 1,550 nm of silicon nitride membranes attached to a silicon frame. Our approach includes the measurement of the thermal expansion coefficient and the thermal conductivity of the membranes. The membrane and frame temperatures are varied, and translated into a change in stress using finite element modeling. The resulting product of the optical absorption and thermo-optic coefficient (dn/dT) is measured using photothermal common-path interferometry

Organizational conflict : in a performing arts organization

Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1985.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH.Bibliography: leaves 161-165.by Sheila L. Strain-Bell.M.C.P

Optical absorption of ion-beam sputtered amorphous silicon coatings

Low mechanical loss at low temperatures and a high index of refraction should make silicon optimally suited for thermal noise reduction in highly reflective mirror coatings for gravitational wave detectors. However, due to high optical absorption, amorphous silicon (aSi) is unsuitable for being used as a direct high-index coating material to replace tantala. A possible solution is a multimaterial design, which enables exploitation of the excellent mechanical properties of aSi in the lower coating layers. The possible number of aSi layers increases with absorption reduction. In this work, the optimum heat treatment temperature of aSi deposited via ion-beam sputtering was investigated and found to be 450 °C. For this temperature, the absorption after deposition of a single layer of aSi at 1064 nm and 1550 nm was reduced by more than 80%

Enhanced Vascularization of Cultured Skin Substitutes Genetically Modified to Overexpress Vascular Endothelial Growth Factor11The authors declared in writing to have no conflict of interest.

Cultured skin substitutes have been used as adjunctive therapies in the treatment of burns and chronic wounds, but they are limited by lack of a vascular plexus. This deficiency leads to greater time for vascularization compared with native skin autografts and contributes to graft failure. Genetic modification of cultured skin substitutes to enhance vascularization could hypothetically lead to improved wound healing. To address this hypothesis, human keratinocytes were genetically modified by transduction with a replication incompetent retrovirus to overexpress vascular endothelial growth factor, a specific and potent mitogen for endothelial cells. Cultured skin substitutes consisting of collagen-glycosaminoglycan substrates inoculated with human fibroblasts and either vascular endothelial growth factor-modified or control keratinocytes were prepared, and were cultured in vitro for 21 d. Northern blot analysis demonstrated enhanced expression of vascular endothelial growth factor mRNA in genetically modified keratinocytes and in cultured skin substitutes prepared with modified cells. Furthermore, the vascular endothelial growth factor-modified cultured skin substitutes secreted greatly elevated levels of vascular endothelial growth factor protein throughout the entire culture period. The bioactivity of vascular endothelial growth factor protein secreted by the genetically modified cultured skin substitutes was demonstrated using a microvascular endothelial cell growth assay. Vascular endothelial growth factor-modified and control cultured skin substitutes were grafted to full-thickness wounds on athymic mice, and elevated vascular endothelial growth factor mRNA expression was detected in the modified grafts for at least 2 wk after surgery. Vascular endothelial growth factor-modified grafts exhibited increased numbers of dermal blood vessels and decreased time to vascularization compared with controls. These results indicate that genetic modification of keratinocytes in cultured skin substitutes can lead to increased vascular endothelial growth factor expression, which could prospectively improve vascularization of cultured skin substitutes for wound healing applications

A survey of engagement and competence levels in interventions and activities in a community mental health workforce in England.

National Health Service (NHS) mental health workforce configuration is at the heart of successful delivery, and providers are advised to produce professional development strategies. Recent policy changes in England have sharpened the focus on competency based role development. We determined levels of intervention activities, engagement and competence and their influencing factors in a community-setting mental health workforce. Using a modified questionnaire based on the Yorkshire Care Pathways Model we investigated 153 mental health staff working in Coventry and Warwickshire NHS Trust. A median score of competence was computed across 10 cluster activities. Low engagement and competence levels were examined in a logistic regression model. In 220 activities, Monitoring risk was the highest rate of engagement (97.6%) and Group psychological therapy/Art/Drama therapy was the lowest engagement (3.6%). The median competence level based on all activities was 3.95 (proficient). There were significant differences in the competence level among professional groups; non-qualified support group (3.00 for competent), Counsellor/Psychologist/Therapist (3.38), Occupational therapists (3.76), Nurses (4.01), Medical staff (4.05), Social workers (4.25) and Psychologists (4.62 for proficient/expert). These levels varied with activity clusters; the lowest level was for Counsellor/Psychologist/Therapist in the accommodation activity (1.44 novice/advance beginner) and the highest for Occupational therapists in personal activity (4.94 expert). In a multivariate analysis, low competence was significantly related to non-qualified community support professions, late time of obtaining first qualification, more frequencies of clinical training, and training of cognitive behavioural therapy. The associations were similar in the analysis for 10 activity clusters respectively. There was a reasonable competence level in the community-setting mental health workforce, but competence varied with professional groups and cluster activities. New staff and other non-qualified support professions need to receive efficient training, and the training content is more important than frequency to increase level of competence

Reflective Diary for Professional Development of Novice Teachers

Many starting teachers of computer science have great professional skill but often lack pedagogical training. Since providing expert mentorship directly during their lessons would be quite costly, institutions usually offer separate teacher training sessions for novice instructors. However, the reflection on teaching performed with a significant delay after the taught lesson limits the possible impact on teachers. To bridge this gap, we introduced a weekly semi-structured reflective practice to supplement the teacher training sessions at our faculty. We created a paper diary that guides the starting teachers through the process of reflection. Over the course of the semester, the diary poses questions of increasing complexity while also functioning as a reference to the topics covered in teacher training. Piloting the diary on a group of 25 novice teaching assistants resulted in overwhelmingly positive responses and provided the teacher training sessions with valuable input for discussion. The diary also turned out to be applicable in a broader context: it was appreciated and used by several experienced university teachers from multiple faculties and even some high-school teachers. The diary is freely available online, including source and print versions