Image tube

An optical image is projected onto a planar surface of a photocathode that derives an electron beam replica of the image. A target electrode displaced relative to the photocathode so that it does not obstruct the optical image includes a planar surface for receiving and deriving an accurate replica of the electron beam image. The two planar surfaces are parallel. The electron beam image is focused on the target electrode by providing throughout a region that extends between the planar surfaces of the photocathode and receiving electrode, constant homogeneous dc electric and magnetic fields. The electric field extends in a direction perpendicular to the planar surfaces while the magnetic field extends along a straight line that intersects the photocathode and target electrode at an acute angle

A magnetically focused image tube employing an opaque photocathode

Image converter has been developed which uses opaque photocathode for improved efficiency. Device is easier to fabricate than previous semi-transparent photocathode converters and uses compounds from Groups 3-5 that are responsive to wave-lengths between ultraviolet (approximately 100 nm) and near infrared region (approximately 1000 nm)

Wide-angle flat field telescope

Described is an unobscured three mirror wide angle telescopic imaging system comprised of an input baffle which provides a 20 deg (Y axis) x 30 deg (X axis) field of view, a primary mirror having a convex spherical surface, a secondary mirror having a concave ellipsoidal reflecting surface, a tertiary mirror having a concave spherical reflecting surface. The mirrors comprise mirror elements which are offset segments of parent mirrors whose axes and vertices commonly lie on the system's optical axis. An iris diaphragm forming an aperture stop is located between the secondary and tertiary mirror with its center also being coincident with the optical axis and being further located at the beam waist of input light beams reflected from the primary and secondary mirror surfaces. At the system focus following the tertiary mirror is located a flat detector which may be, for example, a TV imaging tube or a photographic film. When desirable, a spectral transmission filter is placed in front of the detector in close proximity thereto

Atmospheric X-ray emission experiment for shuttle

An experiment designed to measure the spatial, temporal, and energy distribution of X-ray aurorae produced by precipitating electrons, is presented. The experiment will provide vital data on solar-terrestrial relationships that may lead to defining the transfer mechanism that causes certain terrestrial weather events and climatological behavior. An instrument concept is discussed, and is based on a spatially sensitive multiwire proportional counter, combined with collimators to produce X-ray images of the aurorae. An instrument pointing system, on which the counter can be mounted, will provide the required altitude control, and can be operated by a Spacelab payload specialist for full control over its observing and data taking modes

A photoelectron spectroscopic investigation of conducting polypyrolle-polyamide composite film

Cataloged from PDF version of article.X-ray photoelectron spectrum of the electrochemically prepared polypyrrole and polypyrrole-polyamide composite films exhibit an additional strong high binding energy peak at 402.0 eV corresponding to N+ moieties. Intensity of this peak is significantly reduced upon electrochemical reduction. Atomic concentrations derived from the observed N+ and F (stemming from the dopant BF4-) peaks reveal a slightly higher cation/anion ratio for this composite and suggest that the composite has a different chemical composition than the corresponding polymers. © 1995 Elsevier Science B.V.X-ray photoelectron spectrum of the electrochemically prepared polypyrrole and polypyrrole-polyamide composite films exhibit an additional strong high binding energy peak at 402.0 eV corresponding to N+ moieties. Intensity of this peak is significantly reduced upon electrochemical reduction. Atomic concentrations derived from the observed N+ and F (stemming from the dopant BF4-) peaks reveal a slightly higher cation/anion ratio for this composite and suggest that the composite has a different chemical composition than the corresponding polymers

Communicating choice: an exploration of mothers' experiences of birth

YesObjective: This article gives an in-depth insight into the ways in which communication between midwives and the birthing woman shape the birth experience. Background: Birth is a significant life event for many women that can have profound, long-lasting effects on how they see themselves as women and mothers. Within the literature the importance of control over the birth experience and the support that the birthing woman receives from midwives is stressed. Methods: Six women who had recently given birth participated in one-to-one semi-structured interviews designed to explore the kinds of support they received before, during and after their birth. An inductive thematic analysis was employed in order to identify and explore key issues which ran throughout the interviews. Results: Within the interviews the importance of being an active mother, someone who made decisions in relation to her labour, was stressed. The analysis explores the ways in which communication style and compassionate care either enabled or prevented women from adopting the position of ‘active’ mother. Conclusion: It is argued that a personal connection with midwives and clear and open communication which places the birthing woman in a position of control are key to positive birth experiences

Imaging and Treatment of Patients with Acute Stroke: An Evidence-Based Review

Evidence-based medicine has emerged as a valuable tool to guide clinical decision-making, by summarizing the best possible evidence for both diagnostic and treatment strategies. Imaging plays a critical role in the evaluation and treatment of patients with acute ischemic stroke, especially those who are being considered for thrombolytic or endovascular therapy. Time from stroke-symptom onset to treatment is a strong predictor of long-term functional outcome after stroke. Therefore, imaging and treatment decisions must occur rapidly in this setting, while minimizing unnecessary delays in treatment. The aim of this review was to summarize the best available evidence for the diagnostic and therapeutic management of patients with acute ischemic stroke

Secondary school pupils' preferences for different types of structured grouping practices

The aim of this paper is to explore pupils’ preferences for particular types of grouping practices an area neglected in earlier research focusing on the personal and social outcomes of ability grouping. The sample comprised over 5,000 year 9 pupils (aged 13-14 years) in 45 mixed secondary comprehensive schools in England. The schools represented three levels of ability grouping in the lower school (years 7 to 9). Pupils responded to a questionnaire which explored the types of grouping that they preferred and the reasons for their choices. The majority of pupils preferred setting, although this was mediated by their set placement, type of school, socio-economic status and gender. The key reason given for this preference was that it enabled work to be matched to learning needs. The paper considers whether there are other ways of achieving this avoiding the negative social and personal outcomes of setting for some pupils

Stakeholder perspectives on new ways of delivering unscheduled health care: the role of ownership and organisational identity

<b>Rationale, aims and objectives</b>: To explore stakeholder perspectives of the implementation of a new, national integrated nurse-led telephone advice and consultation service (NHS 24), comparing the views of stakeholders from different health care organisations. <b>Methods</b>: Semi-structured interviews with 26 stakeholders including partner organisations located in primary and secondary unscheduled care settings (general practitioner (GP) out-of-hours co-operative; accident and emergency department; national ambulance service), members of NHS 24 and national policymakers. Attendance at key meetings, documentary review and email implementation diaries provided a contextual history of events with which interview data could be compared. <b>Results</b>: The contextual history of events highlighted a fast-paced implementation process, with little time for reflection. Key areas of partner concern were increasing workload, the clinical safety of nurse triage and the lack of communication across the organisations. Concerns were most apparent within the GP out-of-hours co-operative, leading to calls for the dissolution of the partnership. Accident and emergency and ambulance service responses were more conciliatory, suggesting that such problems were to be expected within the developmental phase of a new organisation. Further exploration of these responses highlighted the sense of ownership within the GP co-operative, with GPs having both financial and philosophical ownership of the co-operative. This was not apparent within the other two partner organisations, in particular the ambulance service, which operated on a regional model very similar to that of NHS 24. <b>Conclusions</b>: As the delivery of unscheduled primary health care crosses professional boundaries and locations, different organisations and professional groups must develop new ways of partnership working, developing trust and confidence in each other. The results of this study highlight, for the first time, the key importance of understanding the professional ownership and identity of individual organisations, in order to facilitate the most effective mechanisms to enable that partnership working