Abyssal ocean circulation driven by geothermal fluxes

PhD ThesisGeothermal heating is increasingly recognised as an important factor a ecting ocean circulation, with modelling studies suggesting that this heat source could lead to rst-order changes in the formation rate of Antarctic Bottom Water, as well as a signi cant warming e ect in the abyssal ocean. Where it has been represented in numerical models, however, the geothermal heat ux into the ocean is generally treated as an entirely conductive ux, despite an estimated one third of the global geothermal ux being introduced to the ocean via hydrothermal sources. In this project I use analytical and computational modelling methods to explore how the geothermal heat ux a ects the deep ocean in both its forms, conductive and hydrothermal. There is a focus on the Panama Basin in the eastern equatorial Paci c, as the bathymetry and prevalence of geothermal heating in the region make it an appropriate area to study. The main di erence between the two geothermal mechanisms is the addition of a volume ux through the seabed for the hydrothermal heating. The circulations caused by such a volume ux through the seabed - initially ignoring the attending heat uxes - are the focus of the rst section of this thesis. It can be seen that these ows have the potential to drive abyssal circulations signi cantly di erent from those resulting from heating the bottom water. The second section of the project takes a close look at how the partitioning of a heat ux between conductive and hydrothermal sources a ects the circulation and hydrography in an idealised domain. In the rst study of its kind, a hydrothermal input is added to the bottom boundary of a primitive equation model and simulations are completed to look at how the circulation changes as the proportion of the heat ux entering the ocean in this way increases. It is found that vertical transport of heat from the abyss is increased when hydrothermal uxes are present. In the nal section, a 3-dimensional regional model of the Panama Basin is used to simulate the e ects of geothermal heating on circulation in a semi-enclosed ocean basin. Of particular interest is the change to the ow through the deepest channels which connect the basin to the greater Paci c Ocean, where the heat transport is doubled. The simulations indicate that geothermal heating of the basin is a signi cant driver of its overturning circulation.I was supported financially by a NERC studentship (NE/JS00227/1) via the National Oceanography Centre and Durham University, and by the OSCAR project (NE/I022868/1)

Osteoprotegerin reduces the development of pain behaviour and joint pathology in a model of osteoarthritis

Acknowledgements: OPG-Fc was a kind gift from Amgen Ltd. Funding: This work was supported by Arthritis Research UK, grant number 18769Peer reviewedPublisher PD

Effects of three oral analgesics on postoperative pain following root canal preparation: a controlled clinical trial

Aim  To compare the effects of single doses of three oral medications on postoperative pain following instrumentation of root canals in teeth with irreversible pulpitis. Methodology  In this double‐blind clinical trial, 100 patients who had anterior or premolar teeth with irreversible pulpitis without any signs and symptoms of acute or chronic apical periodontitis and moderate to severe pain were divided by balanced block random allocation into four groups of 25 each, a control group receiving a placebo medication, and three experimental groups receiving a single dose of either Tramadol (100 mg), Novafen (325 mg of paracetamol, 200 mg ibuprofen and 40 mg caffeine anhydrous) or Naproxen (500 mg) immediately after the first appointment where the pulp was removed, and the canals were fully prepared. The intensity of pain was scored based on 10‐point VAS before and after treatment for up to 24 h postoperatively. Data were submitted to repeated analysis of variance. Results  At the 6, 12 and 24 h postoperative intervals after drug administration, the intensity of pain was significantly lower in the experimental groups than in the placebo group ( P   0.05). Conclusion  A single oral dose of Naproxen, Novafen and Tramadol taken immediately after treatment reduced postoperative pain following pulpectomy and root canal preparation of teeth with irreversible pulpitis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/89451/1/j.1365-2591.2011.01950.x.pd

Sea control & maritime power projection for Australia: maritime air power and air warfare

Australia is a maritime nation in one of the most complex open ocean, littoral and archipelagic maritime regions in the world. The sea is the defining physical characteristic in the region. The overwhelming significance of this is that Australia has no land borders. This is a strategic advantage that must be better understood to avoid it becoming a strategic liability. Strategic realities endure. There are many more effective ways to overcome Australia other than via a military invasion. However, defence against such an invasion is currently the prime force structure determinant in Australian defence planning. As an alternative to this, Australia should better appreciate that a mature maritime capability would provide the mobility and power projection to deter aggressors engaged in operations against Australias interests at distance from Australia itself. Such an understanding would lead to the implementation of a credible maritime strategy. Underpinning such a maritime strategy is the strategic concept of sea control. Sea control requires control of the air. Without sea control maritime power projection cannot occur and forces cannot be operated ashore. Additionally trade to and from Australia can be interdicted at will. However, the central role of sea control for Australias strategic security remains obscured by Australias consistent continentalist approach. It is time to bring maritime strategy to the fore, to re-engage the aircraft carrier issue and to stress the fundamental imperative for capable surface combatants. This would ensure that sea control is the enabler that underpins Australias defence policy. A mature Australia should relegate the vitriolic single-service oriented debates that concluded in 1983 about aircraft carriers to that era. A study should be conducted to rigorously review the technology, operational concepts and strategic realities of 2003 to 2040, with respect to Australias maritime strategic circumstances. As the Australian Defence Force makes decisions on new projects that will affect force structure for the next 30 years, a maritime sea control and power projection requirement should input significantly to the new aerospace combat capability, Project Air 6000, and the project for the maritime air warfare capability, Project Sea 4000

Land-use planning and control along the interstate highway system in Georgia

Final report by Harry W. Atkinson and Howard K. MenhinickIssued as Progress report no. 1-4, and Final report, Project no. B-23