Searching for multifractal scaling in gamma ray burst time series

We present a multifractal analysis of GRB time series used to quantify the variability of the light curve. We discuss the advantages and disadvantages of multifractal analysis, including sensitivity to noise, and burst intensity, and present results for a few sample bursts.     

Book reviews

Kakadu: natural and cultural heritage and management

E.J. Press, D.A.M. Lea, A. Webb & A. Graham (eds), 1995

Australian Nature Conservation Agency & North Australia Research Unit, Australian National University, Darwin

17 × 25 cm, xviii + 318 pp., ISBN 0–7315–2171–4, A$29.95 (soft)

The landforms of England and Wales

A. Goudie, 1993 (first published in hardcover in 1990)

Blackwell, Oxford

23 × 15 cm, xi + 394 pp., ISBN 0–631–16367–0, A$45.00 (soft)

Technological change and the city

P.N. Troy (ed.), 1995

Federation Press, Sydney

14 × 21 cm, vi + 202 pp., ISBN 1–86287–184–1, A$35.00 (soft)

Oceanic islands

P.D. Nunn, 1994

Blackwell, Oxford

17 × 25 cm, xv + 413 pp., ISBN 0–631–17811–7, A$90.00 (soft)

Aotearoa and New Zealand: a historical geography

A. Grey, 1994

Canterbury University Press, Christchurch

14 × 21 cm, xix + 476 pp., ISBN 0–908812–34–5, NZ$29.95 (soft)     

The lightcurve and phase function of the asteroid 304 Olga

Photoelectric lightcurves of 304 Olga were obtained at Table Mountain Observatory in 1978 near opposition. From these observations, and several observations made from Lowell Observatory a month later, we obtain a rotation period of 18.36 ± 0.02 hr and lightcurve amplitude of 0^m·20. The range of solar phase angle covered by the observations is from 2°·0 to 22°. The resulting phase function is well fit by the Bowell and Lumme model (1979, in Asteroids, T. Gehrels, Ed., pp. 132–169, Univ. of Arizona Press, Tucson), with Q = 0.02. This low value of Q is suggestive of a low-albedo object.     

Exploration of an alluvial aquifer in Oman by time-domain electromagnetic sounding

 One-third of the population of Oman depends upon groundwater extracted from the alluvium of the Batinah Plain, on the coast of the Gulf of Oman. Deep geophysical exploration techniques were used to determine the depth and nature of the alluvium and the boundaries of the aquifer. The base and structural controls of the alluvial basin at its contact with Tertiary marine sediments and Cretaceous ophiolite were mapped with seismic reflection data, recorded originally for oil exploration. The base of the alluvium dips northward from the foothills of the Northern Oman Mountains, reaching a maximum depth of 2000 m at the coast. The varying facies of the alluvium are grossly characterised by different, overlapping ranges of electrical resistivity, depending largely on the clay content and degree of cementation. Resistivities near the coast are reduced by saline intrusion. These variations of resistivity were mapped with time-domain electromagnetic sounding along 400 km of profile, to distinguish among the three zones of the alluvial aquifer. The wedge of saline intrusion was also delineated, up to 10 km from the coast. The thickness of the saturated gravel aquifer ranges from 20–160 m in an area greater than 600 km². Received, April 1997 · Revised, January 1998 · Accepted, April 1998     

Large-Area Back-Illuminated CCD Imager Development

We describe recent work in the area of large, back-illuminated CCD imagers at M.I.T. Lincoln Laboratory as well as new technology applicable to astronomy. We completed in 1995 the development of a 2560 x 1960-pixel frame-transfer imager that filled a 100-mm wafer and several back-illuminated versions of this device were completed. More recently we have begun the development, in collaboration with the U. of Hawaii, of a three-side abuttable 2k x 4k CCD for a multi-chip focal plane. In the unused chord area of the wafer layout, we added test imagers as development vehicles for blooming control and for the demonstration of a CCD that is capable of charge transfer in all four directions. We expect the latter to find application as an electronic means of performing tip-tilt correction to compensate for atmospheric turbulence.     

The wollongong lead study: an investigation of the blood lead levels of pre‐school children and their relationship to soil lead levels

The Wollongong Lead Study was undertaken in 1989–90 by the Pollution Task Force of Healthy Cities Illawarra and the Health Promotion Unit of the Illawarra Area Health Service. It was done in response to community concern in the Port Kembla area about the health effects of known high atmospheric lead levels, which result from the emissions from the Electrolytic Refining & Smelting Pty Ltd (now Southern Copper) smelter. It followed procedures similar to those used in the extensive and long‐term studies of the consequences of emissions from the lead smelter at Port Pirie in South Australia and concentrated on the highest risk group identified by the Port Pirie work, namely very young children (mainly 1–3 years). This paper reports the aspects of the study related to soil‐blood level relationships.

Two areas were compared: a southern area near the smelter; and a northern area near Bellambi which was used as a control because it is not usually affected by air pollution from the industrial zone at Port Kembla. A total of 164 soil samples and 83 blood samples were collected from the southern area, together with 79 soil samples and 30 blood samples from the northern area. Soil lead levels were not high by world standards in either region. The southern area had greater levels than the northern area. While there was no apparent pattern in the northern area, soil lead levels rose significantly towards the smelter at Port Kembla. Blood lead levels were also higher in the southern area. Here they rose from the south towards the industrial area generally, rather than peaking near the smelter. In the northern area there was no pattern apparent. Soil levels were significantly correlated with blood levels (significance level >0.05) and explained 29 per cent of the variation in the blood data. Soil lead levels can be used, therefore, as a general indicator of likely high blood lead levels in young children. Seven children (8%) in the southern area and two children (7%) in the northern area had blood lead levels above the NH&MRC recommended level of concern (25 μg/dL).     

IGU commission geographical education

The International Geographical Union Reports

IGU commission geographical education     

Mariner 9—Image processing and products

The purpose of this paper is to describe the system for the display, processing, and production of image-data products created to support the Mariner 9 Television Experiment. Of necessity, the system was large in order to respond to the needs of a large team of scientists with a broad scope of experimental objectives. The desire to generate processed data products as rapidly as possible to take advantage of adaptive planning during the mission, coupled with the complexities introduced by the nature of the vidicon camera, greatly increased the scale of the ground-image processing effort.This paper describes the systems that carried out the processes and delivered the products necessary for real-time and near-real-time analyses. References are made to the computer algorithms used for the, different levels of decalibration and analysis.     

High dispersion observations of Venus during 1972: The CO2 band at 7820Å

Forty-seven well exposed photographic plates of Venus which show the spectrum of the carbon dioxide band at 7820Å were obtained at Table Mountain Observatory in September and October 1972. These spectra showed a semiregular four-day variation in the CO₂ abundance over the disk of the planet (Young et al., 1974). We also find evidence for temporal variations in the rotational temperature of this band and temperature variations over the disk. The two quantities, CO₂ abundance and temperature, do not show any obvious relationship; however, an increase in the temperature usually is accompanied by a decrease in the abundance of CO₂. The average temperature, found from a curve-of-growth analysis assuming a constant CO₂ line width, is 249±1.4K (one standard deviation). This temperature is noticeably higher than the rotational temperature of 242±2K found for this same band in 1967 (Schorn et al., 1969) and of 242±1.2K in 1968–1969 (Young et al., 1971).     

Photoelectic lightcurve and phase relation of the asteroids 505 Cava

Photoelectric observations of 505 Cava taken on 8 nights at the Table Mountain observatory in the fall of 1982 give a period of rotation of 8.1796 ± 0.0010 hr with an amplitude of 0^m.25. The absolute magnitude vs solar phase angle (phase relation) was measured over the range of phase angle of 10 to 25°. The resulting very steep phase relation is suggestive of a dark object (cf. K. Lumme and E. Bowell, 1981, Astron. J. 86, 1705). The is consistent with the “FC” classification suggested by D. Tholen (1984, Asteriod Taxonomy from Cluster Analysis of Photometry, PhD dissertation, University of Arizona, Tucson) based on eigth color photometry.