No description available.

No description available.

This study describes the conodont palaeontology of Upper Ordovician sections in Avalonia and Baltica. 24 species from 17 genera are systematically described and are attributed to the North Atlantic Realm. Sections can be correlated using graptolites and conodonts. The taxa are typical of the accepted Aphelognathus to Periodon shallow to deep-water biofacies. From the late Caradoc in Avalonia and Baltica, the Amorphognathus and deeper-water biofacies persisted in shelf settings. The stability of this distribution through the Ashgill, a period when Avalonia and Baltica drifted towards sub-tropical latitudes, suggests ocean cooling associated with glaciation was the dominant control on biofacies.Microfacies analysis of the phosphatic Amorphognathus superbus Biozone limestones from the Nod Glas Formation of the Welsh Borders indicates the presence of the oxygen minimum zone. Biofacies distribution in this section reflects the subtle variations in temperature within this unique habitat. A hypothesis is presented for the evolution of Amorphognathus ordovicicus in which range expansion into slope settings enabled parapatric speciation. Amorphognathus ordovicicus evolved gradually from a deeper water ancestor by the loss of the lateral process and cusp adjacent denticles on the M element. The initial and subsequent transgressions of the Ashgill brought Amorphognathus ordovicicus, and its cool water niche, into shelf areas. Gradual evolution in deep-water is predicted by the Plus ça Change model. The crown enamel of Periodon, Protopanderodus and Drepanodus records seasonally entrained growth with periods of refractional growth followed by longer functional episodes. Periodon exhibits reduced growth and comparatively short growth duration. Drepanodus and Protopanderodus show continued growth. It is hypothesised that Periodon was nektobenthic and adapted to harsh but stable conditions in the deep-sea, an r-strategist. Drepanodus and Protopanderodus were nektonic and grew to a large size indicating that they were AT-strategists. Upper Ordovician North Atlantic Realm nektobenthic conodonts were characterised by a high diversity and abundance of small sized individuals compared with coeval shelf faunas, a situation analogous to the modem oceans.

No description available.

No description available.

The aim of this thesis was to advance our understanding of the foraging needs of three North Sea seabirds by using fatty acids analysis, a new tool for seabird ecologists.  The first two chapters describe methodological advances in the form of a method for sampling adipose tissue via live biopsy, a simple method for extracting lipids from a variety of seabird tissues and appropriate statistical analysis for detecting differences in fatty acid profiles between groups of ecological interest.  Different tissue types were investigated as sources of fatty acids for addressing a range of ecological questions. The remaining chapters present results using fatty acid analysis to investigate the diet of the three study species the black-legged kittiwake (<i>Rissa tridactyla</i>), common guillemot (<i>Uria aalge</i>) and northern fulmar (<i>Fulmarus glacialis</i>), focussing on areas of research which have been difficult to explore using conventional techniques.  Diet outside the main breeding season is one such area and fatty acid profiles showed that kittiwake and guillemot sexes fed on similar diets before breeding but male and female fulmars used different foraging strategies.  This sex effect did not persist into the chick-rearing period with males and females of all three species feeding on similar diets.  Distinct seasonal shifts in fatty acid profiles were observed and adult and chick diets were shown to differ in the single prey loading species, the guillemot.  The final chapter presents some of the first evidence suggesting a link between individual variation in diet choice and potential fitness consequences in fulmars.

This thesis explores the prospect of a PRC naval role in the Persian Gulf by 2025 and its implications for the United States Navy, focusing in particular on Beijing's evolving relationship with Iran. Since the last years of the Cold War, China's relationships with the United States and Russia have improved significantly, and China no longer sees these former adversaries as imminent threats. As a result, the People's Liberation Army (PLA) has shifted its strategy from a defensive posture to a forward-looking one. Concurrently, economic developments and progress have raised China's aspirations to become the new regional power in Asia. As such, the PRC's economic sustainability will depend greatly on imported oil. The Persian Gulf will be a strategic focus for China in the near future.

This research will explorethe feasibility of replacing traditional networked desktop personal computers (PC) with a thin client/server-based computing (TCSBC) architecture. After becoming nearly extinct in the early 1990s, thin clients are emerging on the forefront of technology with numerous bandwidth improvements and cost reduction benefits. The results show that TCSBC could provide a practical and financially sound solution in meeting the Navy's need to reduce costs and propagate the latest technology to all personnel. This solution may not meet the requirements of all naval commands. A thorough performance analysis should be conducted of the applications employed and the overall expenditures prior to implementation. / US Navy (USN) author.

Approved for public release; distribution is unlimited. / The unique properties of the temperature and salinity profiles for polar oceans are critical for high-latitude mixed layer thermodynamics. In the Polar regions the water column is coldest and freshest at the surface where ice may be present. This density structure often leads to entrainment and affects both the mixed layer depth and the ice thickness. Thermobaricity, the combined dependence of seawater thermal expansion on temperature and pressure, magnifies the buoyancy flux associated with mixed layer convection. When thermobaricity amplifies entrainment so that the heat into the mixed layer is greater than the heat leaving the water column, the mixed layer warms and any existing ice begins to melt. Similarly, if the heat entrained is less than the heat leaving the column, the mixed layer cools and freezing occurs at the surface. In the former situation a polynya, or region of no ice surrounded by ice coverage, may form. A one-dimensional vertical model is built, and trial cases are run to show the intricate relationships that govern the heat and salt fluxes and subsequent ice thickness. The model shows the importance of thermobaricity to the air-sea-ice interactions. It also offers significant insight into how relatively constant atmospheric forcing can lead to polynya-like conditions. / Ensign, United States Navy

Ocean modeling is usually constrained by the lack of observed velocity data for the initial condition. The diagnostic initialization is widely used to generate velocity data as initial condition for ocean modeling. It integrates the model from known temperature (Tc), salinity (Sc) and zero velocity fields and holds (Tc, Sc) unchanged. After a period of the diagnostic run, the velocity field (Vc) is established, and (Tc, Sc, Vc) fields are treated as the initial conditions for the numerical modeling. During the diagnostic initialization period, the heat and salt 'source/sink' terms are generated at each time step. In this Thesis, the Princeton Ocean Model implemented to the South China Sea demonstrated extremely strong thermohaline sources and sinks generated by the diagnostic initialization. Such extremely strong and spatially non - uniform initial heating/cooling (salting/freshening) rates in the ocean model ma y cause drastic change in thermohaline and velocity fields initially (after the diagnostic run). There is a need to overcome such problems or find alternative methods as diagnostic initialization is extensively used. / Republic of Singapore Navy author.