The middle Cretaceous (sediments of Albian to Turonian) lithostratigraphy and foraminiferal biostratigraphy of the central North Sea has been described using data from fifteen wells. These wells are located in or on the margins of major Cretaceous depocentres, namely the Witch Ground Graben, Dutch Bank, Moray Firth, 'Buchan' and Forth Approaches Basins. The lithology of cuttings, sidewall core, and conventional core samples have been described and with the help of electric logs a lithostratigraphic subdivision of each well has been achieved. In this area of the North Sea the middle Cretaceous sequences are subdivided into five units, these are the Valhall (part), Rodby, Hidra, Plenus Marl and Herring Formations. As an aid to correlation the Hidra and Herring Formations have been further subdivided on lithologic and electric log character. The microfaunal content of cuttings, sidewall core and conventional core samples from eight wells has been analysed and the taxonomy of the stratigraphically valuable foraminifera is briefly discussed. Seven new species (Bigeneria sp.1. and 2. , Textularia sp.1. and 2., Uvigerinamina sp.1., Gyroidinoides sp.1. and Osangularia sp.1.) and two new varieties, (Gavelinella intermedia (Berthelin) var A and var B) of foraminifera are described. The abundance of planktonic taxa allows the erection of a local zonal scheme comprising five bio-stratigraphic zones. The mid-Cretaceous microfaunas have many elements in common with the well documented assemblages recorded in the equivalent onshore sequences. This allows the ages of the middle Cretaceous formations to be interpreted by correlation of their microfaunas (particularly planktonic foraminifera) with those recovered from onshore sequences in which the standard macrofossil zonations have been identified. Lithostratigraphic and biostratigraphic analysis indicates the presence of a significant non-sequence within the middle Cretaceous sections in the area of the Buchan Field. This is correlated with unconformities in the Moray Firth, the Dutch Bank Basin, the Witch Ground Graben, the Fladen Ground Spur and Forties Field area. The mid-Cretaceous geological history of the central North Sea is described and related to that of the surrounding onshore and offshore areas of North West Europe. An overall transgression during the Albian to latest Cenomanian/early Turonian was followed by a brief regression and associated erosion later in the early Turonian. A further episode of transgression which was initiated later in the Turonian probably continued into the Maastrichtian. This transgressive-regressive-transgressive cycle may be related to eustatic fluctuations in sea level in conjunction with the mild tectonic activity which persisted through mid-Cretaceous times.

Many of the early taxonomic studies of fossil sea turtles relied heavily on postcranial evidence. Both the Cheloniidae and Dermochelyidae were erected on detail of the shell and limbs. ‘Desmatochelys’ was originally described in part using cranial evidence, but later workers (Zangerl and Sloan, 1960) suppressed the family on evidence from the shell. Little in the way of comparative work has been undertaken using the cranial morphology of fossil or living forms. This is thought long overdue. The first bone by bone description of the living cheloniids has revealed a large number of taxonomically useful characters and a close relationship between the genera. However, a great deal of interspecific variation was noted. ‘Chelonia mydas’ is considered to format least three subspecies on cranial evidence. The newly described ‘Natator (Chelonia) depressa’ is thought distinct from other living forms. The Dermochelyidae are seen to be a very conservative group and a large number of cranial characters link fossil and living forms. The arterial circulation of Dermochelys is redescribed and the importance of the blood flow to the head for use by the salt secreting glands in electrolyte balance is shown to be important. The Desmatochelyidae is shown to be a family in its own right, and a number of other genera, notably ‘Rhinochelys’ and ‘Notochelone’, are thought members of the group. Many of the basicranial features identified by Gaffney in the 70s for other fossil groups have been shown to be of use in the taxonomic study of the families under review.

No description available.

Compliant Actuators are much safer than traditional stiff joint actuators, but at the cost of high overshoot, positional accuracy, and speed. A damper that varies its damping torque during motion is introduced to alleviate these downsides. The equations of motion for the system are derived and simulated. The simulations demonstrated a decrease in the overshoot and ringing time. A physical proof of concept was manufactured and tested. The results from the physical model were inconclusive due to a fault in the physical model. A more accurate physical test model is proposed, and is simulated.

in English - The application of the non-refoulement principle at sea The aim of my thesis is to analyse how one of very important principles of the international law- the non-refoulement principle is applied at sea and what questions should the states bound by this principle ask in order to apply it properly. The thesis itself is composed of three main chapters. Chapter One deals with the non-refoulement in general and defines its content and how this principle is enshrined in international and regional documents. I also examine what are the aspects of the prohibition of refoulement in customary law and whether can it be at present considered as Customary International Law or not. In Chapter Two the excursion into Maritime Law occurs and also indispensable definition of individual maritime zones of Internal Waters, Territorial Waters, Contiguous Zone and High Seas is provided. In this chapter I also focus on the possible application of the non- refoulement outside the state's territory, i.e. its extraterritorial impact. Last but not least in regard to the operations held at sea it is necessary to define their character and different rights and duties arising from them. Subchapters deal with the "search and rescue" and also with the maritime interdiction programs issues whereas the Tampa case and...

The importance of chemical cues in triggering the settlement of marine invertebrate larvae has long been recognised but very few such cues have been definitively identified. Larvae of the Australian sea urchin Holopneustes purpurascens, which lives enmeshed in the fronds of macroalgae, are induced to settle by a water-soluble cue produced by the host alga Delisea pulchra. This cue was previously identified as a floridoside-isethionic acid complex. I present evidence in this thesis which supports histamine as the true settlement cue for larval H. purpurascens. The settlement cue was isolated from the polar extract of D. pulchra by bioassay-guided cation-exchange chromatography and identified as histamine using nuclear magnetic resonance spectroscopy. Algal derived and synthetic histamine at ~5 ??M induced rapid settlement in 80???100 % of larval H. purpurascens. In the first study of its kind for any marine invertebrate, variation in the distribution of new recruits was compared with quantitative variation in the distribution of histamine in the habitat. More than 90 % of new recruits were found on either the foliose red alga D. pulchra or on coralline turf algae. These algae induced &gt90 % settlement of larvae in laboratory assays after 24 h. D. pulchra contained far higher levels of histamine than all other algae, however, the coralline algae lacked measurable histamine. Seawater collected in situ adjacent to D. pulchra induced up to 16 % settlement of older larvae and contained the highest concentration of histamine (~5 nM). With the exception of coralline algae, variation in settlement and recruitment was consistent with the variation among species histamine contents. Initial results supported a biofilm derived settlement cue from coralline algae. I also showed that older H. purpurascens larvae settle in response to lower concentrations of histamine than younger larvae and required less exposure to histamine (10 ??M) in order to initiate irreversible metamorphosis. Histamine induced settlement of two other echinoids with non-feeding larvae. Histamine did not induce settlement of feeding larvae of two echinoids or settlement of non-feeding larvae of asteroids. Histamine may be a general settlement cue for echinoids with direct development.

Bibliography: leaves 285-314. / Copy of "March 2002" is in Main collection; Acid free copy "April 2002" with some changes to pagination is in Special collection. / xv, 314 leaves ill., maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / "The thesis examines China's geostrategic relations with Asia-Pacific countries with special reference to its naval ambitions toward the region. The thesis concentrates especially on the People's Republic of China (PRC)'s apparent intention to expand its maritime influence into the Western Pacific and the Indian Ocean by putting pressure on the security of sea lines of communication (SLOCs) from the Gulf to the nations of East Asia via the Arabian Sea, the Bay of Bengal, the Straits of Malacca and Singapore, the South China Sea, and the Taiwan Strait." -- ABSTRACT / Thesis (Ph.D.)--University of Adelaide, Dept. of Politics, 2002

A criterion is defined to compare seasonal ice coverage in the Greenland Sea for the years 1900-57, and the areal coverage is graphed using the 1898-1913 average as a standard. The factors wielding possible influence on short-term variations of the ice cover are examined individually and their relative importance established. The influence of ocean currents is evaluated by analysis of hydrosections across the East Greenland Current at 74°-76° N and across the North Atlantic Current in the Faeroe-Shetland channel. Data from the latter area are used for numerical analysis of heat imported to the Greenland Sea by the North Atlantic Current in the 1927-52 period. Details about the Irminger Current's behavior are derived from station data from Denmark Strait and from surface temperatures at Selvogsbanki south of Iceland. Year-to-year variations are found to exist in the flow volumes of all three currents, and correlations with seasonal ice coverage in the Greenland Sea are shown. Above-average precipitation in conjunction with below-average storm activity is found to have negligible influence on the ice regime, and no significant correlation is found. The possible effect of evaporation is computed to be far below the threshold of detectability. Air temperatures in the Norwegian-Greenland Sea region display a trend of increase throughout the period studied, in harmony with a concurrent trend of decreasing ice cover; but no causal relationship is in evidence. The effects of strengths and directions of predominant winds are examined, and good correlations are shown between ice cover fluctuations and easterly wind components at Norwegian coastal stations. At the points of major currents' entrances to and exits from the Greenland Sea the wind effects are complex and cannot be fully evaluated on the basis of existing data. The fluctuations of ocean currents entering and leaving the Greenland Sea and of water movements within the Greenland Sea remain as the apparent determinant of year-to-year variations of the ice cover. / Graduation date: 1968

Graduation date: 1973

Three seismic refraction profiles obtained between 42°N and 43°N along the median valley of the Gorda Ridge, an active spreading center, allow the computation of the velocity structure underlying the valley. Wide angle reflections which appear on the seismic records suggest the existence of a velocity inversion underlying layer 3 and were analyzed in combination with refraction arrivals. The resulting velocity model has a low velocity zone with a directly-determined velocity of 5.72 km/sec, between crust of velocity 6.48 km/sec and Moho of velocity 7.54 km/sec. The velocity inversion is 0.7 km thick and lies 3 km below acoustic basement. Consideration of the velocity structure of the Gorda Ridge, together with other information on processes involved in oceanic crustal formation, suggests a model which is consistent with current knowledge on oceanic spreading centers. In the proposed model, the rise of asthenospheric material on the ascending limb of a convection cell causes the generation of a small percentage of partial melt. The molten fraction tends to coalesce near the top of the ascending limb, forming a region of significant partial melt under the ridge crest. This molten material is the immediate source reservoir for mid-ocean ridge magmas. The geophysical expression of the reservoir is a region of low seismic velocity and low density. As the magma cools from the upper surface, heavy minerals tend to work their way downward, forming a layer of cumulate ultramafic rocks at the base of the crust, while the lighter constituents work upward to form the cumulate gabbros of oceanic layer 3. The injection and extrusion of magmatic material upward leads to the formation of layer 2. The crust under the median valley is in isostatic equilibrium with the partial melt during formation, but as it is displaced laterally from the magmatic center, the entire lithosphere becomes competent and the isostatic depth of compensation moves downward into the mantle. This is thought to cause the familiar ridge crest topography of a median valley and adjacent axial mountains observed at slowly spreading ridges. The features of this general model in the specific case of the northern Gorda Ridge between 42°N and 43°N have been tested by the comparison of theoretical and observed gravity and magnetic anomalies. The computation of the theoretical gravity anomaly for this model gives values which match the observed anomaly. The magnetic data show only the pattern of anomalies expected from sea floor spreading and magnetic field reversals. / Graduation date: 1978