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Notes: Over a period of three years 910 patients have been subjected to laparoscopic sterilization of which 443 have had a follow-up hysterosalpingogram. The results are discussed.Laparoscopic sterilization is safe and efficient.With only 24 to 36 hours in hospital the method is acceptable to women with home responsibilities. Bridge Hospital, County Durham.

Notes: The magnetometric resistivity (MMR) method uses a sensitive magnetometer to measure the low-level, low-frequency magnetic fields associated with the galvanic current flow between a pair of electrodes. While the MMR anomalies of simple structures such as dikes and vertical contacts have been determined analytically, there is a lack of systematic information on the expected responses from simple three-dimensional bodies. We determine the characteristic anomalies associated with square, plate-like conductors, which are excellent models of many base metal mineral deposits.The anomalies of plates of finite size are determined numerically using an integral equation method. A plate is subdivided into many sections and the current flow within each section is solved by equating the electrical field within each section to the tangential electrical field just outside it. When the plate size is small in relation to either the depth or the transmitter spacing, the shape and amplitude of the anomaly produced is closely approximated by a current dipole model of the same length and depth. At the other extreme, a large plate is represented by a half-plane. The dipole and half-plane models are used to bracket the behaviour of plates of finite size.The form of a plate anomaly is principally dependent on the shape, depth and orientation of the plate. A large, dipping plate near the surface produces a skewed anomaly highly indicative of its dip, but the amount of skew rapidly diminishes with increased depth or decreased size. Changes in plate conductivity affect the amplitude of the anomaly, but have little effect on anomaly shape. A current channelling parameter, determined from the conductivity contrast, can thus be used to scale the amplitude of an anomaly whose basic shape has been determined from geometrical considerations.The separation into geometrical and electrical factors greatly simplifies both the interpretation and modelling of MMR anomalies, particularly in situations with multiple plates. An empirical formula, using this separation, predicts the anomaly of two or more parallel plates with different conductances. In addition, the relation between the resolution of two vertical, parallel plates of equal conductance and their separation is determined.The ability of the integral equation method to model plate-like structures is demonstrated with the interpretation of an MMR anomaly in a survey conducted at Cork Tree Well in Western Australia. The buried conductor, a mineralized graphitic zone, is modelled with a vertical, bent plate. The depth to the top of the plate, and the plate conductance, is adjusted to fit the anomaly amplitude as closely as possible. From the modelling it would appear that this zone is not solely responsible for the observed anomaly.

Notes: The cross-hole variant of the magnetometric resistivity (MMR) method requires two bore holes in the vicinity of a conductive target. In the first, two fixed current electrodes are located, one above the other. They are linked to a low frequency current source by cables, the whole system forming a vertical current bipole. In the second, a sensitive coil measures the axial magnetic field as a function of depth. For a uniform earth, if both holes are vertical, the measured component vanishes by symmetry. However, the presence of a local conductor channels the current and causes an anomalous magnetic component which is interpreted to indicate the position, shape and relative conductance of the target.Mineral deposits are often lamellar in form. The conductive disc is the simplest bounded lamella for which MMR responses may be computed. It is excited by a single current source on its axis. The second source and the surface of the earth are assumed to be far away, a valid assumption for down-hole measurements.The numerical method introduces a new integral equation describing the interaction of current dipoles located in the plane of the disc. The equation is solved analytically for a disc of infinite radius, a layer, and the result is compared with a corresponding known boundary value solution.The computed radial current in the disc and the magnetic field generated by it are described in terms of a current channelling number. The magnitude of the computed field is of the order of one nanoTesla for a typical mining problem.

Notes: This second paper concerned with effects of prolonged spring defoliations on two early perennial ryegrass varieties (Cropper and RvP Hay Pasture), an intermediate perennial ryegrass (Talbot) and an early cocksfoot (Roskilde) examines the effects of different closing dates on ear emergence, weekly DOMD (in vitro) and conservation yields. The grasses were mown fortnightly to simulate sheep grazing from January until three closing dates, 19 April, 3 May or 17 May, in 1978 and 1979. A set of plots was left undefoliated. All plots were sampled weekly from 2 or 3 weeks after 17 May until the end of June or early July.Prolonged mowing resulted in a small delaying effect on 50% ear emergence of the ryegrasses. The maximum delay was 3 d with the latest closing date. Under this treatment, ear emergence of the cocksfoot was delayed by an average of 12 d but by only 0–4 d under the earlier closing dates. Delay in date of closing caused a significant delay in the time to reach a given DOMD but the effect was largely confined to the latest closing date and was greatest for the cocksfoot. The time when 670 g kg−1 DOMD was reached was delayed in the ryegrasses by no more than 5 d, except for a 12-d delay in the intermediate ryegrass in 1978 following the late closing date. Under this treatment the delay for the cocksfoot was 8 d in both years. The early ryegrasses produced stemmy regrowths.

Notes: Two early perennial ryegrass varieties (Cropper and RvP Hay Pasture), an intermediate perennial ryegrass (Talbot) and an early cocksfoot (Roskilde) were grazed fortnightly by sheep, mown to simulate grazing or left undefoliated from January to May. The effects of spring management on ear emergence, D-value (in vitro) and conservation yields were assessed in each of the 2 years 1976 and 1977. Grazing and mowing had a similar effect on date of first (5%) and 50% ear emergence of the ryegrass varieties; the effect was an average delay of 2 d in both stages of growth over the 2 years. Defoliations significantly (P〈0·001) delayed the fall in D-value with no significant differences between grazing and mowing in the ryegrass varieties, nor in cocksfoot in 1977. The occurrence of a D-value of 67 was delayed by between 3 and 8 d for the ryegrasses and 9 and 11 d for the cocksfoot. The early ryegrasses produced stemmy regrowths and fell to 67 D-value about 4 weeks after the final defoliations in 1976 and after 5–6 weeks in 1977. The fall in D-value took 7–14 d longer in the intermediate ryegrass. Yields were significantly (P 〈 0·001) reduced by grazing and mowing, particularly in 1976. The DM yield reductions in mid June averaged 25% for the ryegrasses and 41% for the cocksfoot.The results indicate that either first or 50% ear emergence may be used to indicate times when a D-value of 67 will be reached in grazed or ungrazed swards but further work is required to determine the effect of weather conditions on the accuracy of this prediction. An early fall in D-value of early perennials after spring grazing, and a marked reduction in yield of cocksfoot, suggests that these grasses should be used sparingly where spring grazing of fields set aside for conservation is a feature of the farming system.

Notes: Epitaxial yttria-stabilized zirconia (YSZ) films were deposited on (11¯02) sapphire by pulsed laser deposition. The films are formed in a cubic phase with the a axis normal to the substrate surface. Ion beam (2.8 MeV He++) channeling measurements show that the YSZ films are highly crystalline with a channeling minimum yield of 8%. The epitaxial relationship between the film and substrate is further confirmed by a cross-section transmission electron microscopy study. Epitaxial YBa2Cu3O7−δ thin films deposited on YSZ/sapphire have Tc and Jc of up to 89 K and 1×106 A/cm2 at 77 K, respectively.

Notes: Summary. The psychosexual sequelae of diagnosis and treatment of pre-invasive cervical atypia were assessed in three groups of women. The first group included 30 women referred to a colposcopy clinic with an abnormal cervical smear indicating cervical intraepithelial neoplasia (CIN), the second comprised 50 women who were traced as sexual partners of men with penile human papillomavirus (HPV) infection; 26 of them had histologically proven cervical atypia and 24 had no such evidence. The third group included 25 women traced as partners of men with non-specific urethritis and who did not have cervical disease. Before and after questionnaires assessed six aspects of sexual behaviour and responses before diagnosis and 6 months after treatment in women with cervical atypia. These were compared with answers given by women investigated and treated, if necessary, as partners of men with sexually transmitted disease (control group). There were statistically significant adverse psychosexual sequelae associated with diagnosis and treatment of pre-invasive cervical epithelial disease.

Notes: Summary. The effect of a luteinizing hormone releasing hormone analogue (HOE 766) was studied in four patients with hypergonadotrophic amenorrhoea (resistant ovary syndrome). After an initial phase of stimulation, there was a uniform and sustained suppression of gonadotrophin concentrations in all the patients during the 20–24 days of treatment, presumably due to down-regulation of the pituitary receptors. One patient ovulated after stopping treatment.