The influence of surveillance methods on surgical wound infection rates in a tertiary care spinal surgery service

We studied 13 consecutive infants admitted to our Neonatal Intensive Care Unit over 37 months from 1 June 1994 to 30 June 1997, who were diagnosed with severe persistent pulmonary hypertension (PPHN) meeting extracorporeal membrane oxygenation (ECMO) criteria as defined by Bartlett and/or Short. They were managed with conservative ventilation strategy, with emphasis on the use of moderate ventilatory pressures whilst avoiding paralysis. Peak inspiratory pressure (PIP) on intermittent mandatory ventilation was adjusted according to adequate chest excursion. High PIP was avoided. Two main ventilatory techniques were used: 1) low ventilatory rate < or = 40/min, PIP 20 to 30 cmH2O, inspiratory time (IT) 0.5 seconds, positive end-expiratory pressure (PEEP) 5 cmH2O, and 2) high ventilatory rate 100/min, PEEP 0 cmH2O, IT 0.3 seconds. The aim was to keep preductal PaO2 > or = 50 mmHg. We did not sought to achieve alkalotic pH or low PaCO2. When PIP requirements exceeded 30 to 35 cmH2O, the use of an alternative rescue therapy such as pulmonary vasodilator, high frequency ventilation and/or surfactant were considered. Only 1 infant died of PPHN. Low mortality due to PPHN can be achieved using this strategy. There is a need for a randomised controlled trial to compare this strategy with other alternative treatment strategies.     

Spectrum analysis of ionospheric radar returns

A digital method of extracting ionospheric information from the Doppler broadening of radar signals is presented. 1 bit correlation, used by Weinreb in radioastronomy, is applied to measuring autocorrelation functions of ionospheric incoherent scatter returns. Calculated correlation functions are fitted to the observations to derive electron and ion temperatures.     

A computer program for the minimal realization of transfer function matrices

A computer program for finding the minimal realizations of transfer function matrices is described. An example is included to illustrate the procedure.     

Aggregation of the UK's energy conservation options

Should the UK economy grow at an annual rate of $\text{2}\text{1}\text{2}$ to 3 per cent between now and the end of the century, total primary demand for energy might reach about 600 mtce if the nation paid no serious attention to energy conservation. However, the adoption of a rigorous, technology based conservation programme as described in this paper could mean that primary energy demand would be only between 400 and 450 mtce.The main options for saving energy by the application of technology are seen to be as follows, in ranking order: economies in general industrial operations insulation of buildings improvements in the mpg of motor vehicles economies in the production of chemicals economies in the production of steel products widespread introduction of heat pumps combined heat and power/district heatingThe magnitude of the potential savings corresponds to a savings on the national fuel bill, if prices doubled, of nearly £8000 millions a year by the end of the century. The integrated savings over the intervening years could reach £40,000 millions with present-day prices.The reduced rate of growth of energy demand due to pursuing a rigorous energy conservation programme could mean that annual primary demand in the year 2000 would be equal to what it would have been 12 years earlier in the absence of conservation. This ‘buying’ of time could be valuable in terms of developing new energy supply technologies.If the package of conservation measures as described in this paper were actually carried out, a major shift of resources away from the energy supply industries into general manufacturing industry would necessarily occur.Although the pursuance of an all-out energy conservation programme based on appropriate technologies would appear highly desirable, it is unlikely to occur if left to market forces, for various reasons. Government would need to play a conspicuous role in both starting such a programme and in maintaining its momentum over many years.     

Reducing the effect of charge-transfer inefficiency in a c.c.d. video integrator

The usefulness of c.c.d.s as video integrators is limited by the charge-transfer inefficiency of the device. A method of coding the signal before passage through the c.c.d. is described which greatly reduces the effect of this inefficiency.     

Treatment of meats with ionising radiations. XV.—Irradiation of beef from barley-fed animals

Joints of ‘barley beef’, irradiated at a dose level of 0.4 Mrad., were stored at 2° in plastic packages of differing gas permeabilities. Bacterial growth was reduced by the lack of oxygen and/or the accumulation of carbon dioxide. The irradiated meat remained unspoiled for at least 84 days. The useful shelf-life of the beef can be extended greatly by irradiation, but the undesirable colour changes resulting from the exclusion of oxygen remains a serious drawback.     

An experimental determination of the carrier lifetime near the SiSiO2 interface

Leakage currents in phosphorus-gettered (111) silicon have been studied at room temperature using a MOS gate-controlled diode structure. The leakage current and the gate-substrate capacitance have each been measured as a function of gate voltage for different values of reverse bias. From these measurements the carrier lifetime in the depletion region near the SiSiO₂ interface has been deduced. It is found that the lifetime decreases with distance from the interface; an explanation for this is suggested.