Medical standards for the use of 'Scubadoo' - a discussion paper

'Scubadoo' is a novel recreational diving device which operates at a fixed depth of three metres' sea water (msw). The diver is free to move in an air-filled dome replenished by continuous air flow from a scuba tank which is an integral part of the device. Calculations show that the equilibrium concentration of carbon dioxide and oxygen in the dome depend on the volumetric air flow from the compressed air cylinder. Experiments carried out with an air flow of 20 L/min gave gas mixtures consistent with the calculations. This provides the basis of safe design for the air supply to the dome. The medical issues that may arise in the use of the Scubadoo device are discussed. Most of the medical issues which apply to scuba diving are minimised here because of the rigid three msw depth limit. Pulmonary barotrauma and also bronchospasm for asthmatics are theoretically possible but are considered to be low risk conditions in the context of the use of the device. Epilepsy and other conditions likely to cause sudden loss of consciousness are the only contraindications to use of the device. It is concluded that Scubadoo should not be subjected to the same medical restrictions as scuba diving

The Potential of Different Forage Combinations for Green-Chop Silage

On the Canterbury Plains of New Zealand (NZ) there is an opportunity on cropping farms, between summer harvest and autumn/winter sowing, to grow forage crops to make high quality silage. Recently, cereal cultivars have been specifically bred for forage production and suitability for whole-crop silage (de Ruiter et al. 2002), and also high legume (e.g. sulla) content forage mixes have resulted in high quality silages with high lactic acid and soluble carbohydrate content (Niezen et al. 1998). This trial aimed to determine the yield potential of various cereal/legume forage mixtures summer sown and harvested for silage in autumn

Establishment and Growth of Legumes on Uncultivatable Hill Country in East Coast New Zealand

Steep, non-arable hill country is a significant feature of New Zealand farming (Sheath 2011) and large tracts of it have been improved by over-sowing grass and assorted clover species, particularly white clover (Trifolium repens L.). Numerous other legume species are available in New Zealand from similar environments overseas that may be more productive on some steep hill country. Plant breeders in New Zealand have also produced inter-specific hybrids (Williams et al. 2010) with potentially useful attributes. As part of a large project to increase pasture production on non-arable hills, a range of legume species were established at 2 sites in New Zealand in 2012. This paper reports results from the first spring and early summer following establishment

Supplementing Dairy Cows in Late Lactation With High Quality Silages

Agriculture on the Canterbury Plains of New Zealand is a mixture of integrated cropping and pastoral enterprises. Cropping farmers often provide supplementary feed for dairy farmers by growing forages for high quality silage. Such silages can improve milk production by increasing dry matter (DM) intake and/or by alleviating deficiencies of either soluble carbohydrate or protein in pasture (Woodward et al., 2002). Legumes and/or cereals have potential to make large quantities of high quality silage (de Ruiter et al., 2002). This trial aimed to determine milk production and composition differences between three silages fed during late lactation

Improving Summer/Autumn Feed Quality in New Zealand Hill Country

Pasture management in spring has a strong influence on pasture quality in summer and autumn in New Zealand hill country pastures. Manipulation of defoliation frequency and intensity during mid-late spring can impact summer and autumn pasture quality and quantity (Orr et al. 1988). Summer/autumn management is mainly concerned with maintaining herbage quality in summer wet areas and controlling animal pressure in summer dry areas for drought management and winter feed stocks (Clark 1994). Deferred grazing to transfer pasture growth from late spring into summer and autumn deficits is difficult due to detrimental effects on pasture quality, plant density and species composition (Sheath et al. 1987). Various grazing management models have been published to inform hill farmers of pasture management considerations during this period (Smith and Dawson 1977; Sheath and Bircham 1983; Sheath et al. 1987). It has previously been shown that management of late spring surpluses to restrict reproductive growth will increase summer pasture quality through a reduction in accumulated stem and dead material and an increase in clover content (Sheath et al. 1987). However, there is no information on the longevity of these effects. This trial aimed to determine the effect of different defoliation intensities during spring on herbage quality and composition throughout the subsequent summer-autumn period

Successful Establishment of Oversown Chicory and Plantain on Uncultivatable Hill Country

All-year grazing of livestock on steep, non-arable hill country (\u3e 20o slope angle, \u3c 1,000 m elevation) is a significant feature of New Zealand agriculture. Hill country pastures are in various states of improvement depending on factors such as extent of subdivision, fertiliser inputs, plant species introduction, and grazing management. Numerous introduced grass, legume and herb species are available to match the many micro-sites in steep hill country (Kemp et al. 1999). There has been increasing use of the perennial herbs chicory (Chicorium intybus L.) and plantain (Plantago lanceolata L.) in seed mixtures used on a range of topographies, mostly flat to undulating terrain. Advantages of these species include tolerance of drought and high summer temperatures, highly palatable foliage, enhanced mineral content, and high animal growth rates (Stewart 1996; Li and Kemp 2005). Farmers have sown these species on hill country but there is negligible information on their establishment in such landscapes. As part of a large, New Zealand-wide programme to increase pasture productivity on non-arable hill country through new germplasm introduction, chicory and plantain were included in a seed mixture broadcast-sown at a range of sites. This paper reports on the seedling establishment of these two species

The Imprint of Galaxy Formation on X-ray Clusters

It is widely believed that structure in the Universe evolves hierarchically, as primordial density fluctuations, amplified by gravity, collapse and merge to form progressively larger systems. The structure and evolution of X-ray clusters, however, seems at odds with this hierarchical scenario for structure formation. Poor clusters and groups, as well as most distant clusters detected to date, are substantially fainter than expected from the tight relations between luminosity, temperature and redshift predicted by these models. Here we show that these discrepancies arise because, near the centre, the entropy of the hot, diffuse intracluster medium (ICM) is higher tha$achievable through gravitational collapse, indicating substantial non-gravitational heating of the ICM. We estimate this excess entropy for the first time, and argue that it represents a relic of the energetic winds through which forming galaxies polluted the ICM with metals. Energetically, this is onl$ possible if the ICM is heated at modest redshift (z \ltsim 2) but prior to cluster collapse, indicating that the formation of galaxies precedes that of clusters and that most clusters have been assembled very recently.Comment: 5 pages, plus 2 postscript figures (one in colour), accepted for publication in Natur

Stochastic optics: A local realistic analysis of optical tests of Bell inequalities

Stochastic optics may be considered as simply a local realistic interpretation of quantum optics and, in this sense, it is a first step in the reinterpretation of the whole of quantum theory. However, as it is not possible to interpret all the details of quantum theory in a local realistic manner, as shown by Bell’s theorem, minor changes are introduced in the formalism with the consequence that the new theory makes different predictions in some special cases. In stochastic optics, the quantum-operator formalism is simply considered a formal way of dealing with stochastic fields. In particular, the quantum zero point is taken as a real random electromagnetic radiation filling the whole of space. This radiation noise has the same nature as light signals, the only difference being the greater intensity of the latter. We assume that photon detectors have an intensity threshold just above the level of the noise, thus detecting only signals. Transmission of radiation through polarizers follows Malus’s law, but the interplay of signal and noise leads quite naturally to the prediction that the detection probability of some signals is enhanced, which is known to be a necessary condition for the violation of the empirically tested Bell inequalities. In our view, correlated photon pairs are pairs of light signals supercorrelated in polarization, in the sense that, as well as the signal, the accompanying noise is also correlated. Thus stochastic optics allows predictions for the empirical correlations very close, but not identical, to the quantum ones. The theory is applied to the analysis of all experiments designed to test the Bell inequalities by measuring polarization correlations of photon pairs. The predictions agree with quantum optics and experiments within statistical errors, except for the Holt-Pipkin experiment. In this case, the experimental results agree with stochastic optical predictions within two standard deviations while violating quantum optics by four