On open boundary conditions for three dimensional primitive equation ocean circulation models

An open boundary condition is constructed for three dimensional primitive equation ocean circulation models. The boundary condition utilises dominant balances in the governing equations to assist calculations of variables at the boundary. The boundary condition can be used in two forms. Firstly as a passive one in which there is no forcing at the boundary and phenomena generated within the domain of interest can propagate outwards without distorting the interior. Secondly as an active condition where a model is forced by the boundary condition. Three simple idealised tests are performed to verify the open boundary condition, (1) a passive condition to test the outflow of free Kelvin waves, (2) an active condition during the spin up phase of an ocean, (3) finally an example of the use of the condition in a tropical ocean

Passive tracers in a general circulation model of the Southern Ocean

Passive tracers are used in an o?-line version of the United Kingdom Fine Resolution Antarctic Model (FRAM) to highlight features of the circulation and provide information on the inter-ocean exchange of water masses. The use of passive tracers allows a picture to be built up of the deep circulation which is not readily apparent from examination of the velocity or density ®elds. Comparison of observations with FRAM results gives good agreement for many features of the Southern Ocean circulation. Tracer distributions are consistent with the concept of a global ``conveyor belt'' with a return path via the Agulhas retro¯ection region for the replenishment of North Atlantic Deep Water

The South Atlantic in the Fine-Resolution Antarctic Model

The geographical area covered by the Fine-Resolution Antarctic Model (FRAM) includes that part of the South Atlantic south of 24°S. A description of the dynamics and thermodynamics of this region of the model is presented. Both the mean and eddy fields in the model are in good agreement with reality, although the magnitude of the transients is somewhat reduced. The heat flux is northward and in broad agreement with many other estimates. Agulhas eddies are formed by the model and propagate westward into the Atlantic providing a mechanism for fluxing heat from the Indian Ocean. The confluence of the Brazil and Falkland currents produces a strong front and a large amount of mesoscale activity. In the less stratified regions to the south, topographic steering of the Antarctic circumpolar current is important

A 10-Gb/s 1024-way-split 100-km long-reach optical-access network

Optical-access networks have been developed to remove the access-network bandwidth bottleneck. However, the current solutions do not adequately address the network economics to provide a truly cost-effective solution. Long-reach optical-access networks introduce a cost-effective solution by connecting the customer directly to the core network, bypassing the metro network, and, hence, removing significant cost. This paper charts the design and development of a 1024-way-split 100-km 10-Gb/s symmetrical network, which experimentally proves the feasibility of long-reach optical-access networks for both the upstream and downstream transmission

ALBATROSS cruise report

This proposal seeks support for a study of the influence of the Scotia Sea on global ocean circulation. During a 35 day research cruise using RRS James Clark Ross, we shall undertake a high quality hydrographic and tracer survey of the southwest Atlantic in the form of an enclosed box. This box incorporates repeats of three hydrographic sections completed during the last decade, so we shall detect any changes in water mass properties. It crosses the Antarctic Circumpolar Current (ACC) twice and so enables us to quantify its transport. The Scotia Sea is a region believed to exhibit intense water mass modi?cation. Deep waters from the Weddell Sea escape through narrow passages into the Argentine Basin and are also entrained into the eastward flowing ACC. Deep waters flowing east through Drake Passage are believed to undergo freshening and cooling in the Scotia Sea. When taken together with previous hydrographic sections, our survey will complete a set of boxes, so we shall use inverse techniques to determine horizontal and surface fluxes of heat and freshwater in the Weddell Sea, Scotia Sea and Southwest Atlantic. Thus we shall quantify the r^ole of the Scotia Sea in the ocean-atmosphere climate system

Optimisation of a parallel ocean general circulation model

Abstract. This paper presents the development of a general-purpose parallel ocean circulation model, for use on a wide range of computer platforms, from traditional scalar machines to workstation clusters and massively parallel processors. Parallelism is provided, as a modular option, via high-level message-passing rou- tines, thus hiding the technical intricacies from the user. An initial implementation highlights that the parallel e?ciency of the model is adversely a?ected by a number of factors, for which optimisations are discussed and implemented. The resulting ocean code is portable and, in particular, allows science to be achieved on local workstations that could otherwise only be undertaken on state-of-the-art supercomputers

Acoustic scattering in waveguides that are discontinuous in geometry and material property

The scattering of acoustic waves at the discontinuity between two ducts of different heights is considered. At least one of the ducts is bounded by a membrane and, thus, the underlying eigenproblem is non-Sturm–Liouville. A mode-matching procedure, based on an appropriate orthogonality relation, reduces the problem to that of truncating and solving an infinite system of linear equations. The distribution of power between the fluid regions and the membrane(s) is analysed. Further, it is shown that a fundamental property of the truncated system is that the expression for power balance is always satisfied

Cardiotoxicity and cancer therapy

A fundamental concept of treatment is to do no harm. However, with cancer treatment this is not always possible. Chemotherapy is associated with cardiovascular (CV) complications.1,2 This risk is even greater in the elderly patients and patients with established CV disease. More specifically, tachyarrhythmias (eg, cisplatin), bradyarrythmias (eg, paclitaxel), or QT prolongation (eg, dasatinib) have been reported. Furthermore, myocardial necrosis, coronary vaso-occlusion or vasospasm, pericardial disease (eg, cytarabine), endocardial fibrosis (eg, busulfan), and heart failure can occur. Hypotension (eg, fludarabine) or hypertension (eg, vinca alkaloids) has also been reported.1,2 Cardiotoxicity, endothelial injury, and Takotsubo syndrome have been reported in patients treated with 5-fluorouracil (5-FU).3⇓–5 Cardiotoxicity to 5-FU was reported 35 years ago.3⇓–5 Cardiotoxicity of chemotherapy has been reported in patients ranging from children through adults (eg, with anthracyclines or cisplatin).6 Adriamycin-induced myocyte damage has been attributed to the production of toxic oxygen free radicals.7 This can cause lipid peroxidation of membranes resulting in vacuolation, irreversible damage, and myocyte replacement by fibrous tissue.7 The use of angiogenesis inhibitors in cancer therapy is expanding as are the associated adverse CV effects (eg, hypertension, thromboembolism, left ventricular dysfunction, and QTc prolongation).2,8 Vascular endothelial growth factor (VEGF) plays a role in maintaining vascular homeostasis via the production of the vasodilator nitric oxide (NO) and decreased vascular resistance through the generation of new blood vessels.2,8 Therefore, it is not surprising that inhibition of VEGF signaling (eg, … [Full Text of this Article

Psychological effects of music tempi during exercise

The purpose of this study was to investigate the effects of music tempi on intrinsic motivation, flow, and music tempo preference during longduration exercise (~ 26 min). Subjects (n = 29) selected the music of a single artist then walked at 70% of maximum heart rate reserve (maxHRR) on a treadmill under three experimental conditions (medium tempi, fast tempi, and mixed tempi) and a no-music control. A tempo preference item, the Intrinsic Motivation Inventory, and Flow State Scale-2 were completed after each trial. Data were analyzed using a mixed-model (Gender × Condition) ANOVA and MANOVA. The Gender × Condition interaction was nonsignificant in both analyses (p > 0.05). Contrary to expectations, higher preference scores were recorded for medium tempi than for mixed tempi (means: 7.8 ± 1.3 vs. 7.1 ± 1.1). The medium tempi music also yielded the highest levels of intrinsic motivation (p < 0.001). Pairwise comparisons showed that interest-enjoyment was higher for medium tempi when compared to mixed tempi, 95% CI = 1.80–8.48, p = 0.001, and that each of the experimental conditions yielded higher scores than the no-music control. Also, pressure-tension was lower for medium tempi compared to fast tempi, 95% CI = – 3.44–0.19, p = 0.022, and for both medium and mixed tempi compared to control (95% CI = – 5.33–2.89, p = 0.000; 95% CI = – 4.24–0.64, p = 0.004). A main effect was found for global flow (p = 0.000) with the highest mean score evident in the medium tempi condition (14.6 ± 1.5). Follow-up comparisons indicated that the medium tempi condition yielded higher flow scores than the control, 95% CI = 1.25–3.60, p = .000, as did fast tempi, 95% CI = 0.89–3.14, p = 0.000, and mixed tempi, 95% CI = 1.36–3.76, p = 0.000. It was concluded that a medium tempi music program was the most appropriate for an exercise intensity of 70%maxHRR