20,626 research outputs found
Flow angle sensor and readout system
Sensor determines fluid flow angles by means of a simple vane that positions itself in the direction of the flow. The vane rotates a small light-reflecting disc as it moves while the readout system uses two cyclically polarized light beams
Millivolt signal limiter
Low-voltage limiter circuit suppresses the output of platinum probes at temperatures beyond their operating range. The limiter circuit comprises an operational amplifier with a dual feedback loop. The signal limiter is useful in low-voltage instrumentation circuits normally operable or set for cryogenic temperatures
Electronic high pass filter
Ultra accurate filter is used with static type pressure transducers where it is desirable to extract low frequency dynamic signals from combined static and dynamic signal. System can be calibrated at any time with dc voltages
Low level signal limiter
A limiting circuit is described which prevents a signal being supplied to a signal amplifier from exceeding a predetermined value. The circuit is designed to permit a signal voltage to be fed directly to a signal amplifier without passing through the operational amplifier and without being altered undesirably. When the signal level increases to the predetermined value, the summing point shifts from the input of the operational amplifier to the output of the limiting circuit
Magnetic local time dependency on cusp ion velocity dispersions in the mid-altitude cusp
Observations of cusp ion velocity dispersions made by the TIMAS instrument on the Polar spacecraft in the mid-altitude cusp during intervals of northward interplanetary magnetic field (IMF) reveal a clear ordering with magnetic local time (MLT). Between 1100 and 1300 MLT the injected ion velocity increased with invariant latitude for 78% of the cusp crossings, between 0900 and 1100 MLT this percentage reduced to 35% and between 1300 and 1500 MLT the percentage reduced to 57%. In contrast similar observations made during intervals of southward IMF revealed no MLT dependency. Between 0900 and 1500 MLT the injected ion velocity increased with invariant latitude for only 17% of the observed cusp crossings. We suggest that the difference in the MLT dependency between northward and southward IMF can be best explained by the different characteristics of polar convection patterns for sub-solar and lobe reconnection
The impact of extended services in Kent
In 2011 The Learning Plus team of Kent County Council, approached Canterbury Christ Church University and requested they undertake an evaluation of the impact of extended services.
Learning Plus approached five providers of extended services who would be willing to provide data for this evaluation. These were selected under three criteria. They were geographically spread through the county and included different school types: special schools, primary and secondary and one was organised as a cluster.
Data was collected in three forms. A desk based review was undertaken of previously published studies of the impact of extended services. This was combined with a review of the QES self-evaluation and evidence supplied by each of the participating providers for the achievement of this quality mark. From this, areas of focus for primary data collection were established. These areas were: Attainment and Attendance, Motivation and Self-esteem and Family and Community. To gather further information in relation to these themes, a series of semi-structured interviews were arranged with representatives of the schools. During these meetings the researchers also discussed and collected any examples of quantitative data that demonstrated the potential impact of extended services.
In relation to attainment and attendance, Aylesham Primary School (part of the DES, Dover Extended Services consortium) provided evidence of greater improvement than would have been predicted without extended schools interventions. Christ Church CEP School provided evidence of greater gains than peers. Whilst a primary school in West Kent were able to demonstrate positive impact on the behaviour of a targeted group of siblings after an intervention.
In relation to motivation and self-esteem, members of the DES cluster used the Strengths and Difficulties Questionnaire (SDQ) to show a change in a child’s self-rating before and after a transitions project. Maplesden Noakes School reported improvement in teacher’s assessment of various aspects of their children’s skills and attitudes, including attitude to learning.
These quantitative measures were all supported by qualitative comments from staff. These indicated that in their view extended services, if not the actual factor, had certainly contributed a great deal to the positive impacts observed.
Impacts on families and communities are, by their nature, harder to quantify, however senior leaders from Milestone School, Christ Church CEP School and Dover Grammar School (part of DES) for example, all felt involvement in extended services had helped improve their family and community relations and improved their image more widely. Indeed, this was typical across the schools within the sample.
Many schools provided specific classes and support for parents, community groups and local businesses, thus having an additional social and economic impact. Furthermore, some schools reported additional benefits. For example, they obtained a return on investment through the use of their facilities
Optical Continuum and Emission-Line Variability of Seyfert 1 Galaxies
We present the light curves obtained during an eight-year program of optical
spectroscopic monitoring of nine Seyfert 1 galaxies: 3C 120, Akn 120, Mrk 79,
Mrk 110, Mrk 335, Mrk 509, Mrk 590, Mrk 704, and Mrk 817. All objects show
significant variability in both the continuum and emission-line fluxes. We use
cross-correlation analysis to derive the sizes of the broad Hbeta-emitting
regions based on emission-line time delays, or lags. We successfully measure
time delays for eight of the nine sources, and find values ranging from about
two weeks to a little over two months. Combining the measured lags and widths
of the variable parts of the emission lines allows us to make virial mass
estimates for the active nucleus in each galaxy. The virial masses are in the
range 10^{7-8} solar masses.Comment: 24 pages, 16 figures. Accepted for publication in Ap
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