Accurate amniotic fluid bilirubin analysis from the "bloody tap". A preliminary report

Prolonged isolation of rats resulted in hyperactivity in the open field and a significant increase in 24 hr urinary excretion of MHPG (3-methoxy-4-hydroxyphenylglycol). Exploratory activity of group-housed rats in open field was not associated with raised MHPG excretion, compared with that of rats remaining in home cages. Exposure of group-housed rats to 4 degrees C for 2 hr also increased urinary excretion of MHPG. Pretreatment of isolated rats with dl-, d-propranolol or practolol abolished hyperactivity of isolated rats and reduced MHPG output in these rats and in rats exposed to cold. dl-Propranolol did not reduce activity of group-housed rats in open field or their urinary excretion of MHPG. It is suggested that propranolol may have a selective inhibitory effect on stress-induced increases in noradrenaline turnover.     

Gas entrainment at the free surface of a liquid: entrainment inception at a vortex with an unstable gas core

Experiments have been performed using sodium, water, white spirit and Freon 113 in a simple small-scale system, to determine the conditions necessary for gas entrainment inception at a vortex with an unstable gas core. The results demonstrate that surface tension effects play a major role and hence they must not be ignored when developing an entrainment-free system.     

Digital Electronic Control of Automatic Ventilators

We have developed a digital system for use in ventilator control. The basic principle of this system is that every respiratory cycle is divided into a fixed number of counts. The control of the ratio of inspiration time to expiration time is accomplished by selecting a variable time out of the fixed time interval and designating it inspiration time. The remaining counts become expiration time. Respiratory rate is adjusted by varying the total time interval, and the ratio is adjusted by selecting a different inspiration time. The output of a digital-to-analog converter driven by the counters is adjustable and proportional to tidal volume. By inserting read only memories between the ratio scalars and the digital-to-analog converter input, a large number of different inspiration waveforms are generated.     

Fully automatic and fast mesh size specification for unstructured mesh generation

A fully automatic surface mesh generation system is presented in this paper. The automation is achieved by an automatic determination of a consistent mesh size distribution, which is based on geometry rasterisation. The user specifies a minimal and maximal allowed mesh size, and a maximal allowed curvature angle for the complete geometry, or, rather, parts of it. Now, these local curvature and local characteristic lengths of the geometry are computed, which determine the local mesh size. These local mesh sizes are stored and smoothed in a Cartesian background mesh. Afterwards, the triangulation is generated by an advancing front triangulator: the local resolution of the surface triangulation is determined by the mesh sizes stored in the Cartesian background mesh. The object-oriented design and implementation is described. The complete system is very fast due to an efficient parallelisation based on MPI for computer systems with distributed memory.     

Scanned-picture-beam holography for nonrigid objects

A technique is described for holographically recording nonrigid objects by scanning the picture beam in a small, bright spot across the object in a series of short exposures. The reference beam is incident across the entire recording medium during each exposure. This technique can freeze the motion of objects subject to ambient forcings, such as acoustic vibrations. Experiments are described in support of this method. Exposures are in the 1- to 10-ms range with 100 separate object regions. An analysis of certain factors affecting image quality, such as diffraction efficiency, is also presented.     

Regional policy and spillovers from FDI in the UK

This paper tests one of the fundamental assumptions of regional policy makers over the last 20 years. Western governments, in seeking to attract internationally mobile capital have spent significant sums of public money on subsidies and grants. This is justified on the basis that the social returns to FDI are significantly greater than the private returns, due to productivity or technology spillovers from inward investors to domestic industry. However, this paper generates some estimates of these spillovers for both assisted areas and non-assisted areas in the UK, and questions the size of these social returns, arguing that productivity spillovers do not occur in regions where significant inward investment incentives are available.Thanks are due to Holger Gorg, Sourafel Girma, Jim Love, Max Munday, Nigel Pain, Jim Taylor, Colin Wern and to seminar participants in Cardiff, Aston, Lancaster and London for comments on an earlier version of this paper.Received: June 2001/Accepted: May 2003     

Inward investment,transaction linkages and productivity spillovers

The article examines the extent to which foreign manufacturing firms in the UK promote productivity growth in the domestically owned manufacturing sector through their buying and supplying relationships. Evidence for intra- and inter-regional externalities from the presence of foreign manufacturing, and intra- and inter-industry effects is brought to light. Externalities in the domestic sector are most noticeable where foreign manufacturing sells to domestic manufacturing. These externalities are, however, not wholly robust to different specifications of spatial dependence. The findings are positioned in a debate, which has tended to view backward (as opposed to forward) linkages from multinationals to domestically owned supply bases as a critical driver of indirect economic benefits.Received: 14 May 2001, Accepted: 22 April 2003, JEL Classification: C67, L14, O33, R58The authors would like to thank three anonymous referees and Raymond Florax for helpful comments on earlier versions of this article. We would also like to thank John Dewhurst and Malcolm Beynon for comments on earlier drafts.     

Monitoring high-temperature solid-solid phase transitions of HMX with atomic force microscopy

Using high-temperature atomic force microscopy we have observed the solid-solid phase transition of octahydro-1,3,5,7,-tetrazocine (HMX) in real time. Massive surface reconstruction occurs during the first-order transition. The temperature induced increase in void space and surface roughness observed in the delta polymorph of HMX serve to increase the growth rate and volume of shock initiated hot spots and hence reaction sensitivity.     

Spinal shrinkage during repetitive controlled torsional, flexion and lateral bend motion exertions

This experiment analysed the spinal shrinkage due to repetitive exertions confined to each of three separate axes (twist, lateral bend, flexion). While the experiment was performed twice with small technique modifications in the twisting task (and thus two data collections were performed), the essential components were as follows. A total of 20 subjects were loaded with an equal moment of 20 Nm in each of the three axes, on 3 separate days (one axis per day). Subjects performed each task for 20 min at 10 repetitions min(-1), where stadiometer measurements of standing height were taken prior to and immediately following the 20 min exertion. The twisting task demonstrated significant spinal shrinkage (1.81 and 3.2 mm in the two experiments) between the pre- and post-stature measurements while no clear effect emerged for the other two tasks. These data suggest that repetitive torsional motions impose a larger cumulative loading on the spine when compared with controlled lateral or flexion motion tasks of a similar moment.