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Although unconfirmed, the syndrome idiopathic intracranial hypertension (IIH), commonly seen in overweight 20- to 50-year-old women, has been proposed to have its origins in an endocrine-based disturbance of electrolytes. Herein we report on 2 women with IIH and primary aldosteronism (PAL). Aged 57 and 55 (patients 1 and 2), each had a longstanding history of mild-to-moderate arterial hypertension, recurrent hypokalemia, and headaches. They were found to have IIH at ages 51 and 45. PAL was diagnosed at ages 57 and 35, respectively, due to proven left adrenal adenoma in patient 1; and presumptive adrenal nodular hyperplasia in patient 2. This is the first report to appear in the English medical literature that describes an association between IIH and PAL. It raises the prospect that in some cases of IIH associated with arterial hypertension, an autonomous production of aldosterone should be considered.

The inherent difficulties of benchmarking parallel computers and the motivation behind the development of the GENESIS benchmark suite introduce the paper. Some of the broader issues that must be taken into account with any rigorous benchmarking effort on a distributed memory system are then discussed together with a relevant example. The initial version of the GENESIS benchmarks was used to evaluate the SUPRENUM computer. The later releases of the suite have been developed to achieve portability of codes across different distributed memory systems by means of the PARMACS macros. Strict portability is however infeasible due to the relative immaturity of current distributed memory computers and the presence of so many different architectures. Therefore some aspects of transportable software are also described, which were felt important when porting the benchmarks to different parallel platforms.

The paper reviews the problems inhibiting the widespread use of parallel processing by both industry and by software houses. The two key issues of portability of code and of generality of parallel architectures are discussed. An overview of useful computational models and programming paradigms for parallel machines is presented along with some detailed case studies implemented on transputer arrays. Valiant's results on optimally universal parallel machines are reviewed along with the prospects of building truly general-purpose parallel computers. Some remarks on language and software tool developments for parallel programming form the conclusion to the paper.

This paper is concerned with the use of Massively Parallel Processing (MPP) systems by industry and commerce. In this context, it is argued that the definition of MPP should be extended to include LAN/WAN clusters or 'meta-computers'. The frontier for research for industry has moved on from mere parallel implementations of scientific simulations or commercial databases-rather, it is concerned with the problem of integrating computational and informational resources in a seamless and effective manner. Examples taken from recent research projects at the Parallel Applications Centre (PAC) are used to illustrate these points.

The aim ofthe project described in this paper was to use modern software component technologies such as CORBA, Java and XML for the development of key modules which can be used for the rapid prototyping of application specific Problem Solving Environments (PSE). The software components developed in this project were a user interface, scheduler, monitor, various components for handling interrupts, synchronisation, task execution and software for photonic crystal simulations. The key requirements for the PSE were to provide support for distributed computation in a heterogeneous environment, a user friendly interface for graphical programming, intelligent resource management, object oriented design, a high level of portability and software maintainability, reuse of legacy code and application of middleware technologies in software design.

Desloratadine is a novel antiallergic therapy for allergie rhinitis, chronic idiopathic urticaria and other allergie conditions. The studies reported here demonstrate the potent antihistaminic and antiallergic effects as well as the exceptional safety profile of desloratadine.

Structural performance analysis of the NAS parallel benchmarks is used to time code sections and specific classes of activity, such as communication or data movements. This technique is called whitebox benchmarking because, similarly to white-box methodologies used in program testing, the programs are not treated as black boxes. The timing methodology is portable, which is indispensable to make comparative benchmarking across different computer systems. A combination of conditional compilation and code instrumentation is used to measure execution time related to different aspects of application performance. This benchmarking methodology is proposed to help understand parallel application behaviour on distributed-memory parallel platforms.

Performance visualization is the use of graphical display techniques for the analysis of performance data in order to improve understanding of complex performance phenomena. Performance visualization systems for parallel programs have been helpful in the past and they are commonly used in order to improve parallel program performance. However, despite the advances that have been made in visualizing scientific data, techniques for visualizing performance of parallel programs remain ad hoc and performance visualization becomes more difficult as the parallel system becomes more complex.

Performance is a critical issue in current massively parallel processors. However, to get adequate performance is not an easy task and performance tools are required in order to help the programmer to understand the behaviour of a parallel program.

Parallel High-Performance Computing (HPC) systems are making ever deeper inroads into the traditional vector supercomputer marketplace for large scientific and engineering platforms. MPP systems are at last delivering real levels of application performance that are unattainable with any other computing technology. Lessons learnt from a decade of parallel modelling and simulation applications development on parallel platforms ranging from SIMD machines through workstation clusters to MPP systems will be reviewed. This will be done in the context of two detailed case studies from the areas of structural dynamics and computational chemistry. The problem of porting sequential simulation or modelling packages is vital to enable the widespread deployment of parallel HPC technology throughout industry and commerce. Porting existing commercial packages imposes constraints on code modification that are not present in the development of new parallel application programs. The importance to industry of real parallel programming standards is stressed.

This article covers the historical background to the study of the helium atom by optical methods, and some essential results from the classical and quantum mechanical theory of optical dispersion. A simple undergraduate‐level experiment, designed for refractivity measurements by cw laser interferometry, is described, and the ingredients of the theoretical calculation of the refractivity are discussed. It is shown that careful experimental work in this area can yield information that provides a valuable test of the accuracy and completeness of the available oscillator strength data.

The INMOS transputer, the T414, and the newly-announced floating-point version, the T800, capable of speeds in excess of one Mflop, are powerful and versatile microprocessors which are natural building blocks for multiprocessor arrays. This paper details our experience using transputer arrays in a FORTRAN “farm” mode, in which each transputer runs the same program on different data, and passes the results to a host microcomputer. The transputer hardware used consists of a Meiko Computing Surface machine. Benchmark timings for the T414 are given for the LUND Monte Carlo generator FORTRAN program used to model QCD jet events. Preliminary results obtained using engineering samples of the T800 are also given.

This note describes some of the initial results derived from observations of radar echoes from the moon obtained at 10-cm wavelength at the Royal Radar Establishment, Malvern. The radar, which has been described elsewhere [1], has a transmitter of 2 megawatts peak power with a pulse length of 5 microseconds and a pulse recurrence frequency of 260 per second. The receiver is of conventional design and has a bandwidth of 500 kc/s and a noise factor of 7.5. The aerial used is the 45-foot diameter radio telescope shown in Fig. 1. The telescope is controlled from a mechanical computer that converts the lunar coordinates into azimuth and elevation, which are then fed into a servo drive.

Difficulties in the operation of centimetric wave-length radar equipment at low angles of elevation (less than 10°) have led to a detailed consideration of the influence of ground reflexion. A technique is described for the determination of the relation between the signal strength of the echo from an isotropic reflector and the angle of elevation of the reflector. Measurements obtained over natural ground sites are shown to be in accordance with simple theoretical considerations. The effect of wire-netting artificial screening has been examined, the experimental results being in general agreement with those derived by theoretical treatment of diffraction using Sommerfeld's formula.

A laboratory method is described for measuring the returned signal scattered from an object in an electromagnetic field. Measurements on conducting spheres and discs are compared with theoretical formulae. A new computation of the scattering function for conducting spheres is tabulated.

The signal scattered back from rectangular and triangular plates illuminated edge-on in an electromagnetic field is found to be large when the incident magnetic vector is normal to the plates. Explanations are sought in terms of edge diffraction, and experimental measurements indicate that the currents in the plates are predominant near to edges. The extension of rigorous theoretical results on infinite edges to the derivation of currents in finite edges is discussed; and it is shown what type of modification appears necessary to account for the experimental observations. A method of testing a hypothetical current distribution for the boundary conditions is propounded.

1. In anaesthetized rats, intravenous administration of alpha 2-adrenoreceptor antagonists yohimbine (0.3-3.0 mg kg-1), idazoxan (0.03-0.3 mg kg-1) and raulwolscine (0.3-3.0 mg kg-1) produced a dose-related inhibition of sciatic nerve-(ScN) mediated reflex pupillary dilation (parasympatho-inhibition). The rank order of potency was idazoxan greater than yohimbine greater than rauwolscine. 2. Under similar experimental conditions, intravenous administration of alpha 1-adrenoreceptor antagonists prazosin (0.03-1.0 mg kg-1), phenoxybenzamine (0.3-3.0 mg kg-1) and corynanthine (0.03-1.0 mg kg-1) produced a dose-dependent potentiation of the reflex mydriasis with the potency order being prazosin greater than corynanthine greater than phenoxybenzamine. Intravenous yohimbine (1.5 mg kg-1) reversed the potentiation caused by the alpha 1-adrenoreceptor antagonists and blocked the reflex mydriasis. 3. Parasympatho-inhibition and mydriasis elicited by hypothalamic stimulation was not affected by the alpha 2-adrenoreceptor antagonists yohimbine (0.3-3.0 mg kg-1), idazoxan (0.03-0.3 mg kg-1) or the alpha 1-adrenoreceptor antagonist prazosin (0.3-1.0 mg kg-1). 4. Microinjection of prazosin (3-30 ng) into the oculomotor nuclear complex (IIIn), produced a dose-related potentiation, whereas microinjection of yohimbine (0.3-3.0 micrograms) produced a dose-related blockade of reflex mydriasis. 5. The above findings support the hypothesis that ascending mechanisms (e.g. afferent ScN) produce inhibition of parasympathetic oculomotor tone to the iris by activation of central postsynaptic alpha 2-adrenoreceptors. Furthermore, these studies demonstrate that alpha 2-adrenoreceptor antagonists block and alpha 1-adrenoreceptor antagonists potentiate the reflex mydriasis. These actions appear to be localized within the pupilloconstrictor regions of the brain (oculomotor nuclear complex).

The solar radiation spectrum does not normally extend into the 5-metre wave-length region with sufficient intensity to be detectable on radio receiving equipments in commercial or Service use. It is now possible to disclose that, on one occasion during the War, Army equipments observed solar radiations of the order of 105 times the power expected from the sun, assuming that the sun behaves as a perfect black-body radiator at a temperature of 6,000° K.

IT is important both for the understanding of the nature of the localized radio sources and the determination of interstellar radio absorption to extend the measurement of the spectra of the sources to as low radio-frequencies as possible. Ionospheric transmission sets a limit, but by choosing frequencies not too close to the critical frequency, and restricting observations to days of low ionospheric disturbance, reasonably accurate measurements may be obtained. In this way, we have recently made measurements at a frequency of 22.6 Mc./s. (λ = 13.3.m.) by means of an interferometer consisting of two aerials spaced in the east–west direction at 20 wave-lengths apart, thus producing lobes in the aerial pattern at intervals of about 3°. Each aerial consists of an array of six full-wave dipoles giving a vertically directed beam of width ± 22° and ± 9° in the north–south and east–west directions respectively. The recording apparatus is a simplified form of the type described by Machin, Ryle and Vonberg1, whereby the receiver is continually switched to a standard noise diode source which is automatically adjusted by a servo-mechanism to equalize the received radiation.