No abstract available

[en] It is shown how different views about the role of nuclear power lead to quite different, but mutually consistent, conclusions. The conclusions are consistent in that provided that nuclear stations are substituting for fossil-fired power stations, and not used as a way of promoting an all-electric fuel economy, and are not justified as a substitute for oil-wells or coal-mines, then nuclear power can help reduce fossil-fuel consumption. The failure to make this distinction, between substituting for primary or secondary fuels, has caused most of the controversy over the energy-analysis of nuclear power which has recently been raging. Another aspect of the debate concerns the desirability of an 'all-electric' economy and the use of electricity for all purposes. It is shown that only between 20 and 30% of the fuel market could use electricity efficiently, at the moment and this might rise to 35 to 40% if electric transportation systems were developed. (U.K.)

[en] The importance of the economics of energy systems is . discussed. The systems approach embodied in energy analysis is compared with that used in micro-economics. It is shown that energy analysis provides information that must be incorporated into an economic evaluation if that evaluation is to be valid. Among the practical examples that are considered is the use of energy analysis in making a choice between nuclear and coal-fired power stations. It is concluded that on certain assumptions the overall effect of the rise in the price of coal between 1973 and 1976 could be a decrease in the optimum nuclear component in the electricity system. An example is also given where other types of systems effects need to be taken into account in the economic analysis of energy systems. Shortcomings in conventional economic theory are indicated. (U.K.)

[en] Iodine speciation in the oxygen-depleted water mass along the west coast of South Africa was investigated in February 1979. The low oxygen water was related to the presence of a stable density layer with σsub(t) = 26.8, which persists over long time periods. The remineralisation of the area is discussed in terms of the nutrient and iodine profiles and contrasted with deep-sea iodine regeneration. The presence of total iodine concentrations (dissolved and possibly particulate) of up to 6.6 μM is probably accounted for by sediment release. Calculations of possible breakdown rates of phytoplankton suggest a continuous reduction process as the water body travels south, rather than a non-local source of the reduced waters. (author)

No abstract available

[en] It is suggested that the development of alternative energy sources has made them more attractive than nuclear power, due to their characteristics, such as small scale and short lead times, moderate costs and minimal environmental impact. The objectives of energy policy are discussed in relation to forecasts of energy demand. Tables show (a) projected useful energy demands UK; (b) patterns of end-use of energy; (c) costs of heating fuels; (d) net present value of gas purchases; (e) useful-energy by end-use analysis; and (f) primary fuel summary 2025. The contributions of hydro, nuclear, waves, solar, oil, gas and coal are estimated to 2025. (U.K.)

[en] Any future shortage in the energy field will be that of cheap energy, rather than of energy itself. An examination therefore of questions relating to future supply and future costs of fuel is important in contributing to more reliable information leading to better decisions. The author sets out to show that energy analysis supplies information which must be incorporated into an economic evaluation if the latter is to be valid. In establishing the case several systems are examined to show how interactions within energy systems can alter economic evaluations. One of the examples is concerned with the choice between nuclear and coal-fired power stations. The general conclusion from the examples chosen, and numerous others, is that in every case it is a mistake to presume that current prices contain all the information required for an economic decision. (U.K.)

[en] The aim of this study was to investigate subclavian vein patency in patients previously treated by temporary venous cannulation for haemodialysis and to compare the results of radiographic venography with those of radioisotope imaging using technetium-99m pertechnetate. (author)

[en] A clinical study of computed tomography (CT) was undertaken in 35 patients with tumours involving the larynx. Twenty-seven had primary laryngeal neoplasms, five had tumours arising in adjacent structures but invading the larynx and three who had undergone total laryngectomy were investigated for possible recurrence. The findings were compared with conventional radiological methods and clinical assessment. Confirmation was obtained from laryngectomy specimens in four patients and at autopsy in one. CT provided additional pre-operative information on 14 occasions. This included better delineation of submucosal tumour extent, invasion of the pre-epiglottic space and cartilage displacement or invasion. (author)

[en] Purpose/Objective: To review the outcome of patients with vestibular schwannomas treated with stereotactic proton irradiation, both single-fraction and fractionated, in order to establish comparative disease-control rates and morbidities. Materials and Methods: All available records of 31 patients treated with 160 MeV proton irradiation between 1976 - 1990 were reviewed. 19 patients (10 females and 9 males) had unilateral lesions, 12 patients (9 females and 3 males) had neurofibromatosis II. In the NF group the indication to treat was to preserve hearing in 10 patients, while in the non-NF group, the indication to treat in 4 patients was post-surgical recurrence and in 6 was post-operative residual. Treatment techniques were consistent in that 25 patients were treated by one physician with a single fraction of proton irradiation. 6 patients were treated with fractionated irradiation with a combination of 160 MeV protons and 3-D planned megavoltage photons. The mean dose given to the 90% isodose line (encompassing tumor) for single-fraction treatments was 31.4 CGE, with an average target volume of 3.8 cc. The fractionated doses varied from 57.1 to 72.0 CGE delivered at 1.7-1.9 CGE/day. The mean proton component in the fractionated treatments was 72%. Mean tumor diameter in the single-fraction NF group was 2.6 cm and in the non-NF group was 2.4 cm. For the fractionated group mean diameter was 2.3 cm. Results: With a median follow-up of 10.6 years (range 0 - 19), the 1, 5, 10, and 18-year overall actuarial survivals of the group with NF were 91, 82, 63 and 42%, respectively. For non-NF group the same interval actuarials were 100, 100, 94 and 63%, respectively. Actuarial event-free survival (clinical/radiological progression or surgical intervention) for the patients treated with NF was 54% at 1 year and remained at 46% from 5 to 18 years. For the group with no NF, the 1, 5, and 10-year event-free survivals were 73%, 67%, and 58%, respectively. The differences between the two groups' survivals are not statistically significant. Analysis of hearing preservation indicates those patients with NF to have maintained useful hearing in 22% of cases - loss of serviceable hearing occurred either due to irradiation or to tumor progression, requiring surgery and consequent CN 8 resection. Of the non-NF patients, only 25% of those with pre-treatment useful hearing (n=4) retain hearing. Comparison of irradiation regimens indicates rates of hearing preservation to be 30-40% by single-fraction and 50-60% by fractionated technique. Facial nerve complication rates indicate in the NF group a 16% permanent deficit rate, due to probable progression of tumor in all patients. In the non-NF patients, temporary CN 7 palsy occurred in 50%, with permanent deficits occurring in 16% due to tumor progression and another 16% due to irradiation damage. Single-fraction and fractionated irradiation permanent CN 7 deficit rates are 15-40% and 0-10%, respectively. Trigeminal nerve palsies occurred in 3% of patients transiently and 6% permanently after irradiation, with all patients having received fractionated treatment. Of the patients with permanent CN 5 deficits, 50% had NF. Transient edema was noted radiologically in 3 patients, 1 with NF. There were no reported cases of acute hydrocephalus after the irradiation, although 15 of the 31 had distortion of the fourth ventricle prior to irradiation. Ataxia was present initially in 28 patients and worsened with time in 22%. Conclusions: The long-term follow-up of this mixed population of NF/non-NF acoustic neuroma patients suggests similar survival/complication rates to other surgical/irradiation techniques. Surprisingly, the relatively high doses used in this early single-fraction effort did not realize either improved control or worse complication rates compared to more contemporary series