Variability in the growth, feeding and condition of barramundi (Lates calcarifer Bloch) in a northern Australian coastal river and impoundment

Lates calcarifer supports important fisheries throughout tropical Australia. Community-driven fish stocking has resulted in the creation of impoundment fisheries and supplemental stocking of selected wild riverine populations. Using predominantly tag-recapture methods, condition assessment and stomach flushing techniques, this study compared the growth of stocked and wild L. calcarifer in a tropical Australian river (Johnstone River) and stocked fish in a nearby impoundment (Lake Tinaroo). Growth of L. calcarifer in the Johnstone River appeared resource-limited, with juvenile fish in its lower freshwater reaches feeding mainly on small aytid shrimp and limited quantities of fish. Growth was probably greatest in estuarine and coastal areas than in the lower freshwater river. Fish in Lake Tinaroo, where prey availability was greater, grew faster than either wild or stocked fish in the lower freshwater areas of the Johnstone River. Growth of L. calcarifer was highly seasonal with marked declines in the cooler months. This was reflected in both stomach fullness and the percentage of fish with empty stomachs but the condition of L. calcarifer was similar across most sites. In areas where food resources appear stretched, adverse effects on resident L. calcarifer populations and their attendant prey species should be minimised through cessation of, or more conservative, stocking practices

Fish stocking programs: assessing the benefits against long term impacts

OBJECTIVES: 1. Assess movements and ecological impacts of stocked barramundi in a model river and impoundment 2. Determine if barramundi stocking has any discernable adverse genetic impacts on wild populations in a previously stocked river syste

Struggling for food in a time of crisis: Responsibility and paradox

Responsibility is a useful lens through which to examine the current state of food poverty in the UK in the context of the Covid‐19 crisis, noting that this concept contains several paradoxes. Currently, responsibility involves the voluntary sector, the food industry and the state, a situation which the author has been exploring for the last five years in an ethnographic study of food poverty and food aid in the UK. Food aid organizations, especially food banks, have mushroomed during the period of austerity. This reveals the first paradox: namely, that the existence of food banks conveys the message that ‘something is being done’, but in actuality this is very far from being sufficient to meet the needs of either the ‘old’ or ‘new’ food insecure. The second paradox is that at the onset of the crisis, a government which had been responsible for inflicting austerity on the country for 10 years, dramatically reversed some of its policies. However, predictably, this did not change the situation vis‐à‐vis food insecurity. The third paradox is that the frequent rhetoric invoking the two world wars has not resulted in lessons being learned – notably, the creation of a ministry to deal with food and rationing, as in the Second World War. The final paradox relates to Brexit and its likely deleterious effects on food security, particularly if no ‘deal’ is achieved with the European Union, as seems likely. The voluntary food aid sector, try as it may, cannot possibly assume responsibility for the long‐standing and now hugely increased problems of food insecurity. That belongs to the state

Wesson's IMT with a Weylian bulk

The foundations of Wesson's induced matter theory are analyzed. It is shown that the 5D empty bulk must be regarded rather as a Weylian space than as a Riemannian one.The framework of a Weyl-Dirac version of Wesson's theory is elaborated and discussed. The bulk possesses in addition to the metric tensor a Weylian connection vector as well Dirac's gauge function; there are no sources (mass, current) in the bulk. On the 4D brane one obtains a geometrically based unified theory of gravitation and electromagnetism with mass, currents and equations induced by the 5D bulkComment: 29 page

Fertility, Living Arrangements, Care and Mobility

There are four main interconnecting themes around which the contributions in this book are based. This introductory chapter aims to establish the broad context for the chapters that follow by discussing each of the themes. It does so by setting these themes within the overarching demographic challenge of the twenty-first century – demographic ageing. Each chapter is introduced in the context of the specific theme to which it primarily relates and there is a summary of the data sets used by the contributors to illustrate the wide range of cross-sectional and longitudinal data analysed

N-body simulations of gravitational dynamics

We describe the astrophysical and numerical basis of N-body simulations, both of collisional stellar systems (dense star clusters and galactic centres) and collisionless stellar dynamics (galaxies and large-scale structure). We explain and discuss the state-of-the-art algorithms used for these quite different regimes, attempt to give a fair critique, and point out possible directions of future improvement and development. We briefly touch upon the history of N-body simulations and their most important results.Comment: invited review (28 pages), to appear in European Physics Journal Plu

Research specialties as emergent phenomena: Connecting emergence theory and scientometrics

This short paper represents an initial effort to connect the emergence theory literature with the bibliometric, informetric, and scientometic literatures. It begins with a prominent definition of emergence, and then connects each of the components of this definition with the relevant insights about the development of new scientific and technical concepts or research specialties. Finally, it concludes with a discussion of the relationship between these two distinct areas of scholarly inquiry and the need for further exploration of this intersection.Intelligence Advanced Research Projects Activity (IARPA) viapublished or submitted for publicationis peer reviewe

Magnetic Field Generation in Stars

Enormous progress has been made on observing stellar magnetism in stars from the main sequence through to compact objects. Recent data have thrown into sharper relief the vexed question of the origin of stellar magnetic fields, which remains one of the main unanswered questions in astrophysics. In this chapter we review recent work in this area of research. In particular, we look at the fossil field hypothesis which links magnetism in compact stars to magnetism in main sequence and pre-main sequence stars and we consider why its feasibility has now been questioned particularly in the context of highly magnetic white dwarfs. We also review the fossil versus dynamo debate in the context of neutron stars and the roles played by key physical processes such as buoyancy, helicity, and superfluid turbulence,in the generation and stability of neutron star fields. Independent information on the internal magnetic field of neutron stars will come from future gravitational wave detections. Thus we maybe at the dawn of a new era of exciting discoveries in compact star magnetism driven by the opening of a new, non-electromagnetic observational window. We also review recent advances in the theory and computation of magnetohydrodynamic turbulence as it applies to stellar magnetism and dynamo theory. These advances offer insight into the action of stellar dynamos as well as processes whichcontrol the diffusive magnetic flux transport in stars.Comment: 41 pages, 7 figures. Invited review chapter on on magnetic field generation in stars to appear in Space Science Reviews, Springe