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Notes: We describe an ion source based on the spontaneous desorption process. The production, acceleration, and separation processes allow for the production of keV energy polyatomic ions while maintaining a high signal-to-background ratio. Both atomic and polyatomic ions with up to 37 keV energy were generated. Because the spontaneous desorption process is naturally pulsed, the ion source was attached to a dual time-of-flight mass spectrometer for secondary ion mass spectrometry experiments. In this article, we describe the design of both the polyatomic ion source and the mass spectrometer.

Notes: Summary In 19 75 we carried out a survey in Hong Kong to locate Chinese children with congenital dislocation of the hip. Analysis of the available records between 1960 and 1975 gave an observed incidence which was at least 10 times less than found in Caucasians. The age and sex distribution, radiographic findings and the left-sided predominence were similar to Caucasians with congenital dislocation of the hip. However, unlike Caucasian children, the Chinese presented with dislocation and not dysplasia. The mothers of children with congenital dislocation of the hip were compared with a control group with normal children to assess their use of the “Hong Kong” position, in which the children are carried on the back of their mother with their hips in a position of wide abduction. Since only half of the children in either group were carried in this manner, other factors must be responsible for the low incidence of congenital dislocation of the hip in southern Chinese.

Notes: Summary Thirty cases of tuberculosis of the knee followed up for an average of 15 years were reviewed. The majority of patients developed the disease during childhood. All had received standard anti-tuberculous drug treatment. Fifteen were treated conservatively alone, while the other 15 had a debridement type of surgery in addition to drugs. At review, one-third had occasional mild pain, but this was only present in the conservatively treated group. Stiffness, however, was more predominant in the operated and in the late onset groups. Some mild deformity was seen in 17 out of 30 patients and was related not so much to disturbance of epiphyseal growth, but rather, to bone collapse. Interesting X-ray appearances at follow-up were found. The factors which could lead to a good outcome included young age of onset, treatment within six months of onset, and early mobilisation. If the disease is well advanced, surgical treatment will lead to a painless joint, but with greater restriction of joint movement.

Notes: Abstract Ion composition observations from polar-orbiting satellites in the past three decades have revealed and confirmed the occurrence of a variety of ion outflow processes in the high-latitude ionosphere. These processes constitute a dominant source of ionospheric plasma to the Earth's magnetosphere. We review the current state of our observational knowledge on their occurrence, energy, composition, variability, interrelationships, and quantitative contributions to the overall mass input to the magnetosphere. In addition, we identify the prevalent sources and the gaps of our current understanding of these sources.

Notes: Abstract The F3C Cold Plasma Analyzer (CPA) instrument on theFreja spacecraft is designed to measure the energy per unit charge (E/Q) of ions oe electrons in the range 0〈E/Q〈200 V and complements the observations made by the F3H Hot Plasma Experiment. The CPA sensor, which is deployed on a boom, is an electrostatic analyzer which produces angle/energy images of particles incident on the sensor in a plane perpendicular to the boom axis. Charged particles incident normal to the CPA sensor housing axis of symmetry, which coincides with the boom axis, pass through collimators and enter a semi-spherical electrostatic analyzer which disperses particles in energy and azimuthal angle of arrival onto an imaging MCP detector thus producing images of the particle distributions in a plane perpendicular to the boom axis. Measurements are transmitted either as discrete 16×16 (angle/energy) images or as parameters related to the incident particle distribution function. Pixels in the discrete images are separated approximately equally in azimuthal angle while the 16 energy bins are separated approximately geometrically in energy. The ratio of the maximum to minimum energy imaged is programmable up to a maximum of more than a factor of ten, and the energy range itself is also under the control of the processor and can be varied by more than an order of magnitude. The density dynamic range of the sensor is increased by the introduction of an electrostatic gating system between the entrance aperture and the analyzer which can be used to duty-cycle low-energy electrons into the sensor thus keeping the count rate within appropriate levels. To reduce the effects of spacecraft induced perturbations on the lower-energy particle distributions, the sensor portion of the instrument is deployed on a 2 m long boom, perpendicular to the spacecraft spin axis. Spacecraft rotation is used to recover complete (4π) angle/energy distributions every half spin period. In addition, the sensor skin may be biased with respect to the spacecraft ground to offset effects due to spacecraft charging. Current to the skin is monitored, making the exterior of the sensor equivalent to a large cylindrical Langmuir probe. Two separate processing paths for signals from the MCP anode may be chosen; ‘slow’ and ‘rast’. The ‘slow’ pulse processing path provides discrete angle/energy images at a nominal rate of 10 images per second and a peak ‘burst mode’ rate of 100 images per second. The ‘fast’ analog or current mode path provides crude parameterized estimates of densities, temperatures and drift velocities at nominal rates of up to 1000 parameters per second with a burst rate near 6000 parameters per second. Observations of cold ions and electrons in an unperturbed ionospheric plasma are presented which demonstrate the functionality of the instrument. Suprathermal ion observations in a transverse ion energization or acceleration region are also shown which demonstrate many of the small-scale features of these events.