High resolution spectroscopy of the disk chromosphere

Two independent sets of high resolution time series spectra of the CaII H and K emission obtained at the Solar Tower and at the Big Dome of the Sacramento Peak Observatory on September 11th, 1971 are reported. The evolutionary behaviour of the emission first reported by Wilson and Evans is confirmed but the detail of the evolution is found to be more complex. In one case, a doubly peaked feature showing some K₃ emission evolves into a single K₂ (red) peak with no K₃ emission. Coincidentally, a neighbouring doubly peaked feature evolves to a very strong blue peak. In an entirely independent sequence a doubly peaked feature evolves into a single red peak. The K₂ emission then fades completely although the continuum threads are still strong. Finally a strong K₂ blue peak appears. These developments are confirmed by intensity profiles obtained from the spectra.Image motion during the sequences is measured using slit-jaw photographs and changes in the overall pattern of the spectra. It is found to be less than the size of the individual features, i.e. 1–2.While considering that the evolution can be explained by the relative motion of one feature with respect to another during the sequence, it is shown that it is possible to account for all these examples in this way only by invoking coincidence of a very high order.It is concluded that in these cases the observed evolution of the K₂ emission is due to temporal variations in the physical conditions which give rise to them.     

A galactic formation model based on post-big bang fragmentation

A new model of galactic formation is presented. A primeval distribution of angular momentum is derived, which rests on the postulated presence of mass flows at the early stage of the post-big bang universal expansion, when fragmentation occurs. The shape of any particular fragment and its orientation with respect to the mass flow predestine the morphology of the galaxy that will be produced in the subsequent collapse.A fragment-to-disk mapping transform allows examination of the galactic disk mass distributions that result from the postulates of the model. One class of distribution adequately describes the observed luminosity profiles of elliptical galaxies. Another class indicates the allocation of a large mass fraction to an extended disk, and the intrinsic two-sided symmetry of the model further indicates that the disk formation process will begin with the establishment of two major spiral arms.     

Dispute settlement

The provisions of the Draft Convention¹ on dispute settlement are of considerable length and complexity. Part XV (Settlement of Disputes) alone runs to 21 articles covering eight pages and Annexes V-VIII add a further twenty pages.² Rather than subject these draft articles to a detailed analysis on a technical level, with a view to proposing improvements in drafting or in the institutional model employed, this article asks basic questions about the utility and practicability of the system incorporated in the Draft Convention. Although much has been written on the details of the system and the various optional models available to the Conference draftsmen,³ there has been a remarkable absence of debate about some of the fundamental assumptions implicit in the Draft Convention's provisions on dispute settlement.     

Abnormal quiet days and the effect of the interplanetary magnetic field on the apparent position of the Sq focus

b
The effect of the IMF on the position of the Sq focus in summer has been discussed by Matsushita who found an apparent poleward motion of the focus on days when the IMF was directed away from the Sun compared to those when the IMF was directed towards the Sun. However, his analysis took no account of the well known phase variability in Sq(H) . It is shown here that if quiet days are separated into 'normal quiet days', NQDs (defined for a station on the poleward side of the focus as days when the minimum in H occurs between 0830 and 1330 LT) and 'abnormal quiet days', AQDs (minimum in H occurring outside the NQD range), then the apparent poleward motion of the focus only occurs on AQDs and even then only when the IMF is directed away from the Sun. This effect is found to occur in both summer and winter and is probably of magnetospheric origin.     

Measuring the sizes of stars

The Chatterton Astronomy Department aims to apply interferometers with very high resolving power to optical astronomy. The programme of the stellar intensity interferometer at Narrabri Observatory was completed in 1972 and since then the work has been directed towards building a more sensitive instrument with higher resolving power. As a first step a much larger intensity interferometer was designed but was not built because it was large, expensive and not as sensitive as desired. Efforts are now being made to design a more sensitive and cheaper instrument. A version of Michelson’s stellar interferometer is being built using modern techniques. It is hoped that it will reach stars of magnitude +8 and will work reliably in the presence of atmospheric scintillation. It is expected to cost considerably less than an intensity interferometer of comparable performance. The pilot model of this new instrument is almost complete and should be ready for test in 1984. Text of an Academy Lecture delivered at the Raman Research Institute, Bangalore on January 27, 1984.     

The ECOMAN project: A novel approach to defining sustainable ecosystem function

The ECOMAN was initiated in 2001 by the University of Plymouth, UK, Plymouth Marine Laboratory and the Department of the Environment, Fisheries and Rural Affairs (DEFRA) to address the need for more pragmatic assessment techniques linking environmental degradation with its causes. The primary aim of the project was to develop an evidence-based approach in which suites of easy-to-use, cost-effective and environmentally valid biological responses (biomarkers) could be used together to assess the health of coastal systems through the general condition of individuals. A range of sub-lethal endpoints, chosen to reflect successive levels of biological organisation (molecular, cellular, physiological), was evaluated in common coastal organisms showing different feeding types (filter feeding, grazing, predation) and habitat requirements (estuary, rocky shore). Initially, the suite of biomarkers was used in laboratory studies to determine the relative sensitivities of key species within different functional groups to common contaminants. These results were then validated in field studies performed in a range of ecosystems exhibiting different degrees/signatures of contamination. Here, an example is provided of a field study in the Humber Estuary, UK, which illustrates how multivariate statistical analysis can be used to identify patterns of response to discriminate between contaminated and clean sites. The use of a holistic, integrated approach of this kind is advocated as a practical means of assessing the impact of chemical contamination on organismal health and of ranking the status of marine ecosystems.     

Geography and global health

In the wake of the report of the World Health Organisation's Commission on the Social Determinants of Health, Closing the gap in a generation (Marmot 2008), this invited commentary considers the scope for geographical research on global health. We reflect on current work and note future possibilities, particularly those that take a critical perspective on the interplay of globalisation, security and health.     

A paleolimnological record of rainfall and drought from East Java, Indonesia during the last 1,400?years

Variations in the location and strength of convection in the Western Pacific Warm Pool (WPWP) have a profound impact on the distribution and amount of global rainfall. Much of the variability in WPWP convection is attributed to variations in the El Ni?o-Southern Oscillation, for which the long-term trends and forcing mechanisms remain poorly understood. Despite the importance of WPWP convection to global climate change, we have very few paleohydrological reconstructions from the region. Here we present a new paleolimnologic and paleohydrologic record spanning the past 1,400 years using a multi-proxy dataset from Lake Logung, located in East Java, Indonesia that provides insights into centennial-scale trends in warm pool hydrology. Organic matter δ¹³C data indicate that East Java became wetter over the last millennium until ca. 1800 Common Era (CE), consistent with evidence for the southward migration of the Intertropical Convergence Zone (ITCZ) during this time. Superimposed on this long-term trend are four decade- to century-scale droughts, inferred from organic matter δ¹³C and calcite abundance data. They are centered at 1030, 1550, 1830, and 1996 CE. The three more recent droughts correlate with hydrologic anomalies documented in other proxy records from the WPWP region on both sides of the equator, and the two most recent droughts correlate in time with historically documented periods of multiple, intense El Ni?o events. Thus, our record provides strong evidence that century-scale hydrologic variability in this region relates to changes in the Walker Circulation. Human activity within the lake catchment is apparent since 1860 CE.