[en] Climate models are based on the laws of classical physics, though processes which occur on scales smaller than the model grid (or time step) must be approximated (parametrized). This may be done on the basis of theory, observations and laboratory and numerical experiments. Validation of models includes detailed verification of individual components of the model, and the comparison of results from the full model over a variety of timescales with observational data

[en] Alertness of the global climate and environment change triggered by the effects of the economy of waste of industrial modern society has been raised to governments and populations. World-wide agreements and protocols have been established; they will be improved for action in two major issues: limitation (elimination of CFC's use, reductions of CO2 emissions, increasing energy efficiency, etc.) and adaptation (socio economic impacts, human behaviour, enhancement of predictive models, etc.)

[en] A phytoclimatic study in Spain-Portugal region has shown that the thermicity index It regression on altitude is highly linear in areas with well developed altitudinal gradients. Deviations from linearity are significant in topographically transitional areas and perhaps in areas with scarce altitudinal variation; these deviations are sometimes due to deviations of mean temperatures of the coldest month

[en] The major difficulty with the climatic and global warming modelling approach is the essential lack of observed and reproducible data on which model assumptions can be based and model outputs verified. The development of additional techniques for data collection can contribute to a fuller understanding of how environmental change is manifested at a local and regional scale. The use of thermoluminescence as a possible dating mechanism receives special mention for stratigraphic analysis

[en] In this paper, an application of the eddy correlation technique to the determination of water vapour and CO2 gaseous exchanges of a maquis canopy is presented (Quercus ilex, juniperus oxycedrus, etc.). Experimental data of three days measurements are discussed in terms of energy balance, carbon fluxes and carbon-water flux ratio. Application of this technique as a tool for testing ecophysiological models is discussed

[en] After a short historical review, the goals of the ICRU are first presented: definition of quantities and units to be used in the field of ionising radiation, recommendations of measurement procedures for these quantities, definitions of terms and concepts, and investigation and selection of physical parameters. As far as the other international organisations are concerned, some of the main achievements are briefly presented for the IEC, UNSCEAR, ICRP, WHO and IAEA. Besides technical developments and dosimetric intercomparisons, the importance of the education and of the continuous information of the radiologists is stressed. The role played by the CEC in education is recognised in the field of radiation protection in diagnostic radiology

[en] The steady increase in the number of computed tomography (CT) scanners in the UK and elsewhere, together with their relatively high levels of patient irradiation, ensure that CT examinations are now a major contributor to the collective dose from medical radiology. A method has been developed to allow the assessment of dose to radiosensitive organs for the peculiar exposure conditions characteristic of a range of common models of scanner. This approach is based on normalised dose data derived for a mathematical anthropomorphic phantom using Monte Carlo techniques, complemented by measurements with thermoluminescence dosemeters of the absorbed dose free-in-air on the axes of rotation of the scanners. Such scanner-specific data may be used to interpret scanning protocols for particular CT procedures in terms of patient dose. The method has been implemented during national surveys in several European countries and data typical of UK CT practice are presented

[en] The escalating number of radiodiagnostic investigations has, as a consequence, an increase in medical irradiation of patients and of cost of radiological services. Radiologists in USA and UK have since early 1970 questioned the efficacy of various radiological investigations and produced substantial evidence that more rational approaches are necessary. WHO initiated, in 1977, a programme in this direction which has issued four technical reports which give practical recommendations on how to rationalize the use of radiological examinations. Three main directions are considered: (1) Abandonment of routine radiological examinations, as procedures with no clinical or epidemiologic significance and which represent a waste of resources and patient dose. (2) Patient selection for various radiological investigations based on clinical criteria (high, intermediate, low yield). Selected patients have an increased prevalence of the given disease and the predictive value of radiological investigation is much higher. (3) Use of diagnostic algorithms with higher cost/efficiency and risk/benefit ratios, improving the outcome of radiological examinations

[en] Selection of appropriate diagnostic radiation measurement equipment involves a critical review of measurement requirements, a detailed performance assessment of available instrumentation, and in some cases compromise. Described, from a manufacturer's point of view, are the overall system requirements, electronics performance criteria, and detector characteristics that were considered in the design and development of the Radcal 1015, 1515, 2025 and 9010 systems. Discussed are the constituents that comprise system performance and accuracy, with special emphasis on detector energy response and rate response

[en] A computerised method of automatically monitoring tube and generator parameters to perform on-line quality assurance and patient dosimetry has been developed. A microcomputer has been interfaced to a microprocessor controlled X ray generator and dose-area product meter. The instrument prompts the operator to enter details of the examination and projection before an examination is made. The field size and dose-area product are monitored by the instrument. These data, together with information on the tube potential are used to deduce the patient entrance dose and energy imparted. Organ doses are estimated using normalised organ dose data. The accuracy and reproducibility of the instrument have been investigated in a laboratory study. Doses measured in a Rando phantom were compared with calculations made by the instrument. In addition, for each radiographic exposure the instrument will compare various measured quality assurance parameters against their nominal values. The implications of this instrument for both patient dosimetry studies and effective continuous quality assurance are discussed