Low atmospheric pressure stunning (LAPS) is a slaughter technique which may be less stressful for pigs (Sus scrofa domestica) than current commercial stunning and slaughter methods. The main methods used currently for slaughtering pigs are electric and carbon dioxide stunning, both of which are widely recognised as stressful for pigs. There is currently no published research on the use of LAPS for stunning adult pigs, however there is a significant body of relevant experience from investigations into the effects of low pressure and hypoxia on humans, hypoxia for killing pigs and the use of LAPS for killing poultry, rats and piglets. In this paper, the basic physics and biology of LAPS is briefly reviewed and relevant experience from research with humans, poultry, rats and piglets is presented. On the basis of this information, some initial parameters for LAPS trials with pigs are proposed, potential welfare issues identified and an approach to achieving LAPS at a commercially viable speed is outlined. While the effects of LAPS on pigs is, at present, uncertain, the evidence from research with humans and other animals suggests that healthy, fasted pigs undergoing LAPS are unlikely to suffer from air hunger or from pain. Any pigs suffering from upper respiratory tract disease, tooth decay or excess gas in the alimentary canal may, however, experience pain. A total killing cycle is likely to require 9 to 14 min. To implement LAPS in a commercial, high throughput processing plant will require the use of multiple decompression cylinders. The evidence available suggests that LAPS could be commercially viable for pig slaughter and that for most pigs it will be less stressful than current commercial slaughter methods.

Petrological and mineral chemical data are presented for two new occurrences of co-existing borosilicate minerals in the Larsemann Hills, East Antarctica. The assemblages contain kornerupine and the rare borosilicate, grandidierite (Mg,Fe)A13BSiO9. Two distinct associations occur: (1) At McCarthy Point, 1–10 mm thick tourmaline-kornerupine-grandidierite layers are hosted within quartzofeldspathic gneiss; and (2) Seal Cove, where coexisting kornerupine and grandidierite occur within coarse-grained, metamorphic segregations with Mg-rich cores of cordierite-garnet-spinel-biotite-ilmenite and variably developed plagioclase halos. The segregations are hosted within biotite-bearing, plagio-feldspathic gneiss. Textural relationships from these localities indicate the stability of co-existing kornerupine and grandidierite.

The grandidierite- and kornerupine-bearing segregations from Seal Cove largely postdate structures developed during a crustal thickening event (D2) which was coeval with peak metamorphism. At McCarthy Point, grandidierite, kornerupine and late-tourmaline growth predates, or is synchronous, with F3 fold structures developed during a extensive granulite grade, normal shearing event (D3) which occurred prior to, and synchronous with, near-isothermal decompression. Average pressure calculations on assemblages that coexist with the borosilicates at Seal Cove, indicate the prevailing conditions were 5.2–5.5 kbar at ∼ 750°C for formation of the grandidierite-kornerupine assemblage.

Spinel–cordierite–plagioclase symplectites partially replacing andalusite occur in the metapelitic migmatite rocks of the Alvand aureole within the Sanandaj–Sirjan metamorphic belt, Hamadan, Iran. The presence of melt shows that corona development occurred under partial melting conditions. Spinel is predicted to grow with cordierite at around 700°C. Exhaustion of the available SiO2 and/or separation of sillimanite/andalusite from SiO2-rich matrix domains by cordierite resulted in the formation of localized low-silica activity domains and thus triggered the growth of spinel in the rim of andalusite, the reaction Sil/And + Bt = Crd + Spl + Kfs + melt, as the most common reaction for the development of coronas in the metapelitic of Alvand aureole. The breakdown of garnet to plagioclase + sillimanite, dehydration melting and the formation of spinel–plagioclase symplectite could occur during heating or decompression; these textures are limited to the contact aureole in the studied area, so heating is perhaps the more likely explanation for formation of the symplectites in the metapelitic rocks of the Alvand aureole. The P–T diagram, inferred paths and zoning profiles of garnet do not account for the decompression history of the terrane.

This paper evaluates the outcome of retrosigmoid microvascular decompression of the facial nerve in a series of patients suffering from hemifacial spasm who had been referred to the skull-base team (comprising senior authors DAM and DGH). The paper is a retrospective review of 15 patients who underwent retrosigmoid microvascular decompression of the facial nerve at Addenbrooke's Hospital between 1985 and 1995. In this series it was possible to obtain complete resolution of hemifacial spasm in 93.3 per cent of cases in the short term and in 80 per cent in the long term. Twelve patients (80 per cent) were symptom-free post-operatively. Two patients had minor recurrence of symptoms occurring within six months of the procedure. One patient with no identifiable vascular impingement of the facial nerve had no improvement following surgery. Three patients suffered sensorineural hearing loss. Two patients complained of post-operative tinnitus, and transient facial palsy was noted in one patient.

Retrosigmoid microvascular decompression of the facial nerve provides excellent long-term symptom control in a high percentage of patients with hemifacial spasm.

The Amery area of Mac. Robertson Land lies between the early Palaeozoic granulite terrain of Prydz Bay and Meso-Neoproterozoic granulites in northern Prince Charles Mountains (nPCM). In contrast to the nPCM which shows an apparently simple near-isobaric history, granulites exposed in the Amery area contain reaction textures suggesting a more complex evolution. Peak-M1 Mesoproterozoic assemblages formed at c. 700 MPa and 800°C and initially underwent a near-isobaric cooling. A subsequent increase in temperature (M2) resulted in the formation of cordierite-spinel assemblages at ~450 MPa and 700°C in metapelite. The timing of M2 is not firmly established, however existing data strongly suggest it is an early Palaeozoic event coeval with tectonism in Prydz Bay to the north-east. Thus the metamorphic evolution of granulites in the Amery area reflects a terrain-scale thermal interference pattern between two unrelated orogenic events. In rocks not recording post-M1 isobaric cooling, the superposition of M2 on M1 assemblages resulted in the formation of M2 cordierite-spinel symplectites at the expense of peak M1 garnet and sillimanite. This texture, commonly interpreted to reflect near-isothermal decompression, has no relevance in terms of a single tectonothermal event in the Amery area.

Orbital decompression for dysthyroid eye disease is traditionally performed either through an external approach or transantrally. The introduction of endoscopic sinus surgery over the last decade has led to a better understanding of the intranasal surgical landmarks of orbital walls and the development of endoscopic orbital decompression. We have adopted the endoscopic technique as the treatment of choice for orbital decompression in dysthyroid eye disease for the last two years. The surgical technique is described and illustrated, and the results of our first series of 15 patients (30 orbits) are presented.