Phototransistor

A phototransistor is described in which there is included as a part of its integral structure an auxiliary diode in the form of an added base-collector junction. This junction is formed in the surface of the base element and thus out of the direct path between the emitter and collector regions of the phototransistor

Overlap diffusion for increasing phototransistor dynamic range

Construction of improved phototransistors to provide increased base-collector capacitance is described. Silicon or germanium semiconductor wafers are used as examples. Operation of transistors and electrical properties are discussed and illustrations of the devices are included

A policy critique of Stansted Airport's expansion to 25 million passengers per annum (MPPA)

In this paper we undertake a preliminary assessment of the regional planning and development implications of BAA Stansted Airport’s planning permission to grow to 25 million passengers per annum (mppa) by 2010. Our concern is not simply to consider the overall growth of the airport on the airport site itself but the nature and type of growth both on- and off-site. In this document we focus on the submitted planning permission documents and test them. The methodology we employed was to draw on published and unpublished numerical estimates of the airport’s growth – particularly including estimates produced by the airport owner, BAA, and their economic and planning consultants DTZ Pieda - and critically, and systematically analyse their figures. We adopted this approach because unless the figures which were employed in the initial calculations were correct then all of the subsequent projections which flow from them - and the polices which could then be based on them – could be flawed. The analysis is divided into two parts – firstly, are the growth forecasts correct?; and secondly, what do these forecasts actually mean in developmental terms? In effect, what we have done is to produce a critique of the existing body of evidence by questioning underpinning assumptions and then draw some preliminary conclusions for the region based on this analysis. A major focus of this report has been analyse the figures involved in the planning application to expand Stansted to 25mppa. Ironically, one of our key findings, that the local impact of Stansted’s proposed expansion in employment terms might well be less than was originally thought, might make it easier to gain the acceptance of the relevant local authorities involved to allow the development to take place. Our main overall findings are that the BAA projections over-estimate the local employment impact of the airport’s proposed growth and under-estimate its potential regional ‘transportation’ employment effect. These two findings are, of course, related to each other in important ways, and we also feel that they have potentially significant medium and long-term economic, competitiveness and planning policy implications for the East of England regio

Fundamental Properties of Intensity, Form, and Motion Perception in the Visual Nervous Systems of Calliphora phaenicia and Musca domestica

Several classes of interneurons in the optic lobes and brain of the insects, Musca domestica and Calliphora phaenicia, have been studied in detail. Visual stimuli have been categorized on the basis of the properties of intensity, form, and motion. Response characteristics of the classes of neural units are described with respect to these three classes of visual stimuli. While those units that detect motion in select directions have a tonic response, form detection units have a phasic response only. Through correlation of the responses of these classes with visual stimuli, it is shown that these units integrate the responses of other units which have very small visual fields. The small-field units are presumed to integrate the output of a small group of adjacent retinula cells and to respond differentially to intensity, form, and motion. It is shown that the response of both form and motion detection units is independent of the direction of pattern intensity gradation. As a consequence of this independence, it is further shown that failure to detect motion properly must start at a spatial wavelength four times the effective sampling station spacing rather than twice as has been predicted previously

The effect of boar breed type on reproduction, production performance and carcass and meat quality in pigs

peer-reviewedA total of 720 sows were inseminated with semen from eight commercially available boar breed types (Landrace, Large White, Duroc, Landrace Large White, Landrace Duroc, Landrace Large White Duroc, Large White Duroc and Landrace Large White Pietrain). There were no effects of purebred versus crossbred boar breed type on reproductive performance or on production performance of progeny. The only carcass evaluation parameter affected was V measurement (backfat thickness at the edge of the eye muscle) which was 2 mm thicker (P < 0.05) for the progeny of crossbred boars. Meat from pigs of purebred boars breed had a higher proportion of intramuscular fat than that from crossbred boars breed (26.5 v 21.1 g/kg, respectively, P < 0.05). There were inconsistent effects of individual boar breed type on performance, carcass quality and meat qua lity. Producers should consider the variation between the progeny of individual boars to achieve improved production performance. There was also a lack of relationship between backfat at the P2 position and eye muscle area or depth (r −0.03 and −0.01, respectively) which suggests that carcass characteristics other than P2 backfat need to be included in the selection of breeding animals. Similarly, the weak correlations between carcass and meat quality traits (r < 0.3) indicate that if meat quality is to be improved, it must be specifically included in the selection criteria.The authors gratefully acknowledge joint funding for this research from the Pig Production Development Committee in conjunction with the Ulster Farmers’ Union Pigs Committee and the Department of Agriculture and Rural Development for Northern Ireland

Time delay and integration detectors using charge transfer devices

An imaging system comprises a multi-channel matrix array of CCD devices wherein a number of sensor cells (pixels) in each channel are subdivided and operated in discrete intercoupled groups of subarrays with a readout CCD shift register terminating each end of the channels. Clock voltages, applied to the subarrays, selectively cause charge signal flow in each subarray in either direction independent of the other subarrays. By selective application of four phase clock voltages, either one, two or all three of the sections subarray sections cause charge signal flow in one direction, while the remainder cause charge signal flow in the opposite direction. This creates a form of selective electronic exposure control which provides an effective variable time delay and integration of three, six or nine sensor cells or integration stages. The device is constructed on a semiconductor sustrate with a buried channel and is adapted for front surface imaging through transparent doped tin oxide gates

Boson Pairs in a One-dimensional Split Trap

We describe the properties of a pair of ultracold bosonic atoms in a one-dimensional harmonic trapping potential with a tunable zero-ranged barrier at the trap centre. The full characterisation of the ground state is done by calculating the reduced single-particle density, the momentum distribution and the two-particle entanglement. We derive several analytical expressions in the limit of infinite repulsion (Tonks-Girardeau limit) and extend the treatment to finite interparticle interactions by numerical solution. As pair interactions in double wells form a fundamental building block for many-body systems in periodic potentials, our results have implications for a wide range of problems.Comment: 9 pages, 8 figure