A short-pulse, long-wavelength radio-echo sounder has successfully measured the ice depth on the South Cascade Glacier. Depths up to 250 m were determined with resolution of about 5%. Bottom returns were clear and almost never ambiguous. Their accuracy was confirmed by comparison with hot-point drilling results. The secret for successful sounding in temperate glaciers is the use of a sufficiently low center frequency. Five megahertz was most successful. Tests at 15 MHz indicated an increase in coherent clutter which rendered the bottom return observable only with prior knowledge of its location. The cause of the clutter is probably water-filled voids in the ice which behave as Rayleigh scatterers.

The sounding system consists of an avalanche-transistor transmitter, which delivers a pulse to an acute-angle crossed-wire antenna. The pulse is shaped and given its center-frequency characteristics by the resonant properties of the antenna. The transmitting and receiving antennas are identical, consisting of wires and lumped resistors. The resistors reduce antennas ringing, thereby maintaining as short a pulse as possible. The receiver consists of an oscilloscope and a Polaroid camera. No preamplification is required for depths up to 250 m, but may be necessary for deeper glaciers.

We used the process-oriented niche model CLIMEX to estimate the potentialglobal distribution of serrated tussock under projected future climates.Serrated tussock is a drought-tolerant, wind- and human-dispersed grass ofSouth American origin that has invaded pastures in Australia, Europe, NewZealand, and South Africa. The likely effect of climate change on itspotential global distribution was assessed by applying six climate-changescenarios to a previously developed model. The projections of climaticsuitability under the current climate revealed considerable scope forspread, with the most suitable areas occurring adjacent to existingnaturalized populations in Australia, New Zealand, and Western Europe. Underfuture climates, projected to the 2080s, the land area suitable for serratedtussock contracts globally between 20 and 27%. Changes in projectedpotential area under the six scenarios were very similar in all geographicalregions apart from North America and New Zealand, where the projectionsrange from little change or contraction under the National Center forAtmospheric Research (NCAR) and Centre for Climate Research (MIROC) globalclimate models (GCMs) to expansion under the Commonwealth Scientific andIndustrial Research Organisation (CSIRO) GCM. Elsewhere, contractions occurin Australia, Asia, South America, and Africa under all six future climatescenarios. By contrast, for Europe, the area climatically suitable forserrated tussock increases under all six scenarios (average increase 47%)through expansions into eastern European countries that are currentlyunsuitable and through increases in the suitable area in England, Ireland,and Denmark. Since pastoralism is a dominant land use in these regions ofEurope, a prudent biosecurity strategy would be to contain the nascent fociof serrated tussock in southern France, along the west coast of Italy, andin the United Kingdom. This strategy could consist of a set of policies tolimit human-assisted dispersal of the species' seeds and to reducewind-borne spread through cultural control of the plant.

Tall buttercup, a native of central and northern Europe, has becomenaturalized in the United States and Canada, and in South Africa, Tasmaniaand New Zealand. In Canada and New Zealand it has become an economicallysignificant weed in cattle-grazed pastures. In this study we develop aCLIMEX model for tall buttercup and use it to project the weed's potentialdistribution under current and future climates and in the presence andabsence of irrigation. There was close concordance between the model'sprojection of suitable climate and recorded observations of the species. Theprojection was highly sensitive to irrigation; the area of potentiallysuitable land globally increasing by 30% (from 34 to 45 million km2) under current climate when a “top-up” irrigation regime(rainfall topped up 4 mm d−1 on irrigable land), was included inthe model. Most of the area that becomes suitable under irrigation islocated in central Asia and central North America. By contrast, climatechange is projected to have the opposite effect; the potential globaldistribution diminishing by 18% (from 34 to 28 million km2). Thisrange contraction was the net result of a northward expansion in thenorthern limit for the species in Canada and the Russian Federation, and arelatively larger increase in the land area becoming unsuitable mainly incentral Asia and south eastern United States.

‘Testing distribution equipment’ is a simple enough tide, deceptively so, and the superficial simplicity of our subject has in my view been misleading and somewhat detrimental to agricultural aviation development. With this remark made, I will now try to justify it and explain why I think that testing is in fact reasonably complex, even though, because the physical mechanisms are usually straightforward, the subject appears to be more simple than it really is.

Firstly, I would like to take a moment to consider the meaning of the two words ‘distribution’ and ‘testing’.

Most of the recent advances in X-ray astronomy have resulted from satellite observations in the low energy (< 20 keV) range. The Einstein X-ray Observatory in particular has been responsible for a dramatic increase in our knowledge of the X-ray sky, in that all major classes of astronomical objects have been detected.

An apparatus is described for applying a very small volume (0.1–1.0 μl.) of an insecticidal solution to an insect. It comprises a length of precision-bore glass capillary mounted, with a calibrated scale, in one end of a short tube having at the other end a perforated rubber bulb; the capillary is filled to the required scale mark by applying cotton wool saturated with the liquid to its tip, and the liquid expressed by squeezing the bulb, with the forefinger covering the hole in it. It can be used in conjunction with a calculator consisting of two concentric rotatable discs bearing two pairs of scales, on one of which the insect weight (in g.) is apposed to the per cent, concentration (w/v) of insecticide to be applied, which enables the volume (in μl.) required to yield a given dose (in μl./g.) to be read from the other pair of scales. Both devices have been used successfully in field testing with locusts and other insects.

Isoenzyme-based studies have identified 3 taxa/species/‘phylogenetic complexes’ as agents of visceral leishmaniasis in Sudan: L. donovani, L. infantum and “L. archibaldi”. However, these observations remain controversial. A new chitinase gene phylogeny was constructed in which stocks of all 3 putative species isolated in Sudan formed a monophyletic clade. In order to construct a more robust classification of the L. donovani complex, a panel of 16 microsatellite markers was used to describe 39 stocks of these 3 species. All “L. donovani complex” stocks from Sudan were again found to form a single monophyletic clade. L. donovani ss stocks from India and Kenya were found to form 2 region-specific clades. The partial sequence of the glutamate oxaloacetate transaminase (GOT) gene of 17 L. donovani complex stocks was obtained. A single nucleotide polymorphism in the GOT gene appeared to underlie the isoenzyme classification. It was concluded that isoenzyme-based identification is unsafe for stocks isolated in L. donovani endemic areas and identified as L. infantum. It was also concluded that the name L. archibaldi is invalid and that only a single visceralizing species, Leishmania donovani, is found in East Africa.

Annealing experiments were carried out on gallium nitride layers, which were grown on sapphire through Metal Organic Chemical Vapor Deposition (MOCVD). Rutherford Backscattering Spectrometry (RBS) was performed on as-grown and annealed GaN samples using a 2 MeV proton beam to study the stoichiometric changes in the near-surface region (750 nm) with depth resolution better than 50 nm. No decomposition was measured for temperatures o up to 800 °C. Decomposition in the near-surface region increased rapidly with a further increase o of temperature, resulting in a near-amorphous surface-region for annealing at 1100 °C. The depth profiles of nitrogen and incorporated oxygen in the decomposed GaN are extracted from the nanoscale RBS data for different annealing temperatures. The surface roughness of the GaN layers observed by atomic force microscopy (AFM) is consistent with RBS decomposition measurements. We describe the range of annealing conditions under which negligible decomposition of GaN is observed, which is important in assessing optimal thermal processing conditions of GaN for both conventional and nanoscale optoelectronic devices.

At their first meeting Polynices and Tydeus come to blows. They are reconciled by Adrastus, who expresses the hope that their quarrel will lead to loyal friendship between them, as it did.

Esse pro fuisse dixit, says Lactantius, more ingenuously than Klotz, who tries to make the same thing more palatable by saying esse est pro imperfecti quodammodo infinitiuo. Some have taken the accusative and infinitive to be a general statement, but Heuvel is clearly right in saying that it is Tydeus and Polynices whom the poet has in mind. The most favoured solution has been Grater's conjecture isse, but (as Helm says) that produces an unnatural expression (the passages adduced by Mueller are not parallels); Mozley renders it by ‘grew’, thereby translating not what stands in his text but what ought perhaps to stand there, namely <cr>esse, a conjecture of Gil, which has been almost entirely overlooked. This contracted form is found in extant literature only at Lucretius 3.683 and (concresse) Ovid, Met. 7.416 (at 3.200 Statius flesse). The first letters of a line are particularly liable to omission; despite Hill, I do not find it at all surprising that at 1.544 perseus lost its first letter and the remnant became aureus.

The most recent and by far the best edition of this work is that of H. M. Hine (Stuttgart/Leipzig, 1996), to which I refer for full bibliographical information. Many passages of the text are most helpfully discussed in the same scholar's Studies in the Text of Seneca's Naturales Quaestiones (Stuttgart/Leipzig, 1996).

ut nubes infici possint, … sol ad hoc apte ponendus est; non enim idem facit undecumque effulsit, et ad hoc opus est radiorum idoneus ictus.

Seneca is dealing with rainbows. Hine (Studies, 24–5) shares Axelson's suspicion of ictus, but is unhappy both with Axelson's situs (‘seems too static a word for the sun's rays’) and with my tractus, ‘direction’ (‘in this sense seems to be used only of concrete physical objects’); very tentatively he suggests angulus. Much more credible palaeographically and still yielding good sense and a good clausula would be i<mp>etus, a noun which is very common in this work of Seneca's.

Hostius fuit Quadra obscenitatis in scaenam usque perductae.

A scanning electron microscope based cathodoluminescence technique utilizing a novel collector system reveals complex internal heterogeneities within granitic quartz grains. The technique overcomes the low intensity and limited variation in cathodoluminescence generated by quartz, which hamper conventional cathodoluminescence analysis. Detailed images of zoning patterns in quartz are comparable to those observed in minerals such as feldspar, and attributed to a combination of progressive growth, boundary layer effects and mineral–melt disequilibria produced during fluctuations in melt composition and temperature during the crystallization interval. We attribute such mineral–melt disequilibria to open system, mixing behaviour in the granite plutons sampled.

In CQ 45 (1995), 547–50, S. J. Harrison and M. Winterbottom (hereafter H-W) propose a series of emendations to the text of the recently discovered passage of Donatus which contains his commentary on Aen. 6.1–157. I offer some further emendations (bold figures refer to lines of Virgil).