Long-term change in benthopelagic fish abundance in the abyssal northeast Pacific Ocean

Food web structure, particularly the relative importance of bottom-up and top-down control of animal abundances, is poorly known for the Earth's largest habitats: the abyssal plains. A unique 15-yr time series of climate, productivity, particulate flux, and abundance of primary consumers (primarily echinoderms) and secondary consumers (fish) was examined to elucidate the response of trophic levels to temporal variation in one another. Towed camera sled deployments in the abyssal northeast Pacific (4100 m water depth) showed that annual mean numbers of the dominant fish genus (Coryphaenoides spp.) more than doubled over the period 1989-2004. Coryphaenoides spp. abundance was significantly correlated with total abundance of mobile epibenthic megafauna (echinoderms), with changes in fish abundance lagging behind changes in the echinoderms. Direct correlations between surface climate and fish abundances, and particulate organic carbon (POC) flux and fish abundances, were insignificant, which may be related to the varied response of the potential prey taxa to climate and POC flux. This Study provides a fare opportunity to study the long-term dynamics of an unexploited marine fish population and Suggests a dominant role for bottom-up control in this system

A Bioeconomic Model for Management of Orange Roughy Stocks

The paper reports the results of a bioeconomic analysis of the exploitation of a recently discovered orange roughy stock located off Tasmania. The parameters of the model are based on the experience derived from the orange roughy fisheries in New Zealand where stocks have been heavily exploited. The model is used to predict the open-access equilibrium stock, and to calculate the stock which maximizes the net present value and the stock level consistent with the F,,, Rule. Assuming a linear approach path, the net present value of the fishery at each of these stocks is calculated. The results are used to estimate the benefit of management and the cost of a conservative stock policy. It is suggested that the results will contribute to the development of a management policy for the Tasmanian stock, and for stocks which are likely to be discovered elsewhereFishery management, bioeconomic model, orange roughy, Environmental Economics and Policy, Production Economics,

Exploring the compassion deficit debate

Several recent high profile failures in the UK health care system have promoted strong debate on compassion and care in nursing. A number of papers articulating a range of positions within this debate have been published in this journal over the past two and a half years. These articulate a diverse range of theoretical perspectives and have been drawn together here in an attempt to bring some coherence to the debate and provide an overview of the key arguments and positions taken by those involved. In doing this we invite the reader to consider their own position in relation to the issues raised and to consider the impact of this for their own practice. Finally the paper offers some sense of how individual practitioners might use their understanding of the debates to ensure delivery of good nursing care

Ubic: Bridging the gap between digital cryptography and the physical world

Advances in computing technology increasingly blur the boundary between the digital domain and the physical world. Although the research community has developed a large number of cryptographic primitives and has demonstrated their usability in all-digital communication, many of them have not yet made their way into the real world due to usability aspects. We aim to make another step towards a tighter integration of digital cryptography into real world interactions. We describe Ubic, a framework that allows users to bridge the gap between digital cryptography and the physical world. Ubic relies on head-mounted displays, like Google Glass, resource-friendly computer vision techniques as well as mathematically sound cryptographic primitives to provide users with better security and privacy guarantees. The framework covers key cryptographic primitives, such as secure identification, document verification using a novel secure physical document format, as well as content hiding. To make a contribution of practical value, we focused on making Ubic as simple, easily deployable, and user friendly as possible.Comment: In ESORICS 2014, volume 8712 of Lecture Notes in Computer Science, pp. 56-75, Wroclaw, Poland, September 7-11, 2014. Springer, Berlin, German

Formal Derivation of Concurrent Garbage Collectors

Concurrent garbage collectors are notoriously difficult to implement correctly. Previous approaches to the issue of producing correct collectors have mainly been based on posit-and-prove verification or on the application of domain-specific templates and transformations. We show how to derive the upper reaches of a family of concurrent garbage collectors by refinement from a formal specification, emphasizing the application of domain-independent design theories and transformations. A key contribution is an extension to the classical lattice-theoretic fixpoint theorems to account for the dynamics of concurrent mutation and collection.Comment: 38 pages, 21 figures. The short version of this paper appeared in the Proceedings of MPC 201

Limaria hians (Mollusca : Limacea): a neglected reef-forming keystone species

1. A key component of physical habitat along braided river systems is the exposed riverine sediment within the active zone. The relatively unmanaged, gravel-bed Fiume Tagliamento, Italy, provides the focus for exploring two ecologically important properties of exposed riverine sediments: their within-patch and between-patch variability in calibre. 2. To characterize between-patch variation in exposed riverine sediments, replicate (within-patch) samples were obtained from three geomorphologically distinct locations along 130 km of the river: bar heads along the margin of the low-flow channel, the heads of major bars across the exposed surface of the active zone, and floodplain surfaces. A photographic technique enabled rapid and consistent field sampling of the coarse sediments at bar heads along the low-flow channel margin and on major bars across the dry bed. 3. A downstream decrease in particle size and an increase in within-patch heterogeneity in sediment size were observed within bar head sediments along the margin of the low-flow channel. Comparisons between major bar and low-flow channel samples revealed greatest within-patch variability in individual sediment size indices (D50, A- and B-axes of the larger particles) at headwater sites, greatest between-patch variability in the three measured indices in the central reaches, and lowest between-patch variability at downstream sites. However, there was a distinct increase in the overall heterogeneity in particle size, which was sustained across all patches, in a downstream direction. 4. There was a clear downstream decrease in the size of floodplain sediments in the headwaters, but thereafter there was no distinct downstream trend in any of the calculated particle size indices. 5. The geomorphological controls on the observed patterns and the potential ecological significance of the patterns, particularly for plant establishment, are discussed in relation to the relative relief of the active zone, and the highly variable hydrological and climatic regime along the river

Fishmeal replacement research for shrimp feed in Australia

The global expansion and intensification of aquaculture has brought with it an increasing requirement for formulated feeds. Feeds for carnivorous fish and shrimp contain a large proportion ingredient of marine origin, particularly fishmeal. However, despite the continuing increase in demand for fishmeal, world fishmeal production is unlikely to increase further. The identification and development of alternative feed ingredients that can replace fishmeal is recognised as an international research priority. A nationally coordinated research program in Australia has evaluated a wide range of ingredients produced by Australia’s agricultural industries. Information has been obtained on the chemical composition, apparent digestibility (AD) and subsequent assimilation and utilisation of each of the ingredients evaluated. The research focused on three key warmwater species endemic to Australia: the omnivorous marine crustacean, black tiger shrimp Penaeus monodon; the euryhaline carnivorous fish, barramundi or Asian seabass Lates calcarifer and the freshwater omnivorous fish, silver perch Bidyanus bidyanus. Across the three key species, the AD for crude protein was highest for fishmeal though the more refined, high-protein ingredients of plant origin were equally well digested. The AD of energy was relatively low in ingredients with a high carbohydrate or fibre content. Dehulled lupins (L. angustifolius) and high-protein, low-ash meat meals were found to have the greatest potential to replace fishmeal in shrimp diets. Meat meal can replace about half of the digestible crude protein, and dehulled lupins can replace a quarter of the digestible crude protein, in a shrimp diet without significantly affecting biological performance, provided that the balance of the crude protein in the diet comes predominantly from high quality ingredients of marine origin. When the diets contain these ingredients of marine origin at inclusions of at least 50 g.kg-1, specific feeding effectors do not appear to necessary to maintain the palatability of the diets

Results from a Prospective Study of Mortality

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142734/1/Brown-Nesse-Social_Supp-PsychSci-2003.pd