The palaeoceanography of the Leeuwin Current : implications for a future world

Long-term progressive changes of the Leeuwin Current are linked to plate and ocean basin ‘geography’ and Cenozoic global climates and palaeoceanography. Suggestions of the presence of a proto-Leeuwin Current as early as late Middle to Late Eocene times (c. 35–42 Ma) cannot be verified by the fossil record of the western margin of Australia. “Leeuwin Current style” circulation around Australia was certainly established by the early Oligocene, in response to palaeogeographic changes in the Tasman Strait. This, followed by tectonic eorganisation of the Indonesian Archipelago throughout the Miocene, provided a palaeogeographic setting, which by the Pliocene was essentially that of today. The subsequent history of the Leeuwin Current comprises climatically-induced changes operating over orbital and sub-orbital temporal scales. Specifically, the advent of Pleistocene-style climates, especially over the last 800 000 years, and their associated interglacial – glacial states provide the two end-member climate-ocean states that have characterised Leeuwin Current activity during that time. Indications of the nature of these contrasting states is provided by: (i) the Last Interglacial (c. 125 Ka) during which sea level was higher by some +4 m, and with higher sea surface temperatures (SSTs) clearly indicating a more ‘active’ Leeuwin Current; and (ii) the Last Glacial Maximum (21 Ka), during which sea level wassome 130 m lower than today, resulting in massive shelf extensions along the coast of Western Australia, ccompanied by reduced Indonesian Throughflow, lower low latitude SSTs and changes in the Western Pacific Warm Water Pool, and with these changes, possibly reduced Leeuwin Current activity. Sub-orbital scale luctuations in current strength are driven by global climate change associated with El Niño – La Niña events as well as regional climatic changes driven by volcanism. These forcing mechanisms operate at time scales well within the reach of human experience, and provide important comparative data for predicting the response of the Leeuwin Current to climate change predicted for this century. Studies of the impact of changes in the vigour of the Leeuwin Current on shallow marine communities are in their infancy. Coupling climate models with geological analogues provide important research agenda for predicting the trajectory of future changes to the Leeuwin Current and their impacts on the marine biota of coastal Western Australia

Short-Term Funding Markets and Systemic Risk

This dissertation presents two essays to study both theoretically and empirically the interaction of short-term funding and the banking system and its effects on systemic risk. Before its collapse in September 2008, Lehman Brothers had been using the repurchase agreement (repo) market to hide up to $50 billion from their balance sheet at the end of each quarter. When this "Repo 105" scheme was uncovered (a type of strategy called window dressing), the Securities and Exchange Commission conducted an inquiry into public US financial institutions and concluded that Lehman was an isolated case. Using confidential regulatory data on daily repo transactions from July 2008 to July 2014, in my first essay, I show that non-US banks continue to remove an average of$170 billion from the US tri-party repo market every quarter-end. This amount is more than double the $76 billion market-wide drop in tri-party repo during the turmoil of the 2008 financial crisis and represents about 10% of the entire tri-party repo market. Window dressing induced deleveraging spills over into agency bond markets and money market funds and affects market quality each quarter. Demand deposit contracts provide liquidity to investors; however by their nature they can expose the issuer to self-fulfilling runs. Existing models treat depositors as agents facing uncertain liquidity shocks, who seek to insure against that liquidity risk through use of a bank financed solely by deposits. Welfare-reducing bank runs then arise from the inherent difficulties depositors face in coordinating their withdrawals. My second essay extends the classic model of Diamond & Dybvig (1983) to allow for a more realistic mixed capital structure where the bank's investments are partly financed by equity, and where differing incentives between shareholders and depositors are allowed to operate. I also further extend the model to allow shareholders to choose the level of risk in bank-financed projects. I compute the ex-ante probability of a bank run in consideration of the bank capital ratio, and I additionally compute the level of bank risk chosen by utility-maximizing shareholders who are disciplined by uncoordinated depositors. I find that even in the absence of bank negotiating power of the form in Diamond & Rajan (2000), banks can be welfare-improving institutions, and there exists a socially optimal level of bank capital. I consider the policies of a minimum capital requirement, deposit insurance, and suspension of convertibility, and provide guidance on creating optimal bank regulation. I show that the level of bank capital involves a tradeoff between sharing portfolio risk and sharing liquidity risk. Increased bank capital results in less risk-sharing between shareholders and depositors. The demand deposit contract disciplines the bank and its shareholders, and equity capital in effect disciplines the depositors (by making runs less likely). There is a socially optimal level of natural bank capital, even when I make no further social planner restrictions on bank portfolio choice in the model

Automotive Aeroacoustic Sound Quality

Aeroacoustic noise sources are becoming increasingly important in the vehicle environment. Research has suggested that for electric vehicles, the predominant focus in development effort shifts from powertrain noise, to masking noises such as road and aeroacoustic. Despite this, the consumer perception of automotive aeroacoustic sound quality is a remarkably under researched field; few examples of literature have previously investigated this area, with fewer still employing qualitative techniques. This publication summarises a two phase research project. Initially, focus groups were conducted, to gather information on the ways in which a variety of consumer demographics perceive aeroacoustic sound quality. Rigorous grounded theory analysis of the discussions identified six core categories: the perceived acoustic character of the sound, the conditions and environment, the balance of the aeroacoustic sound (spatially, spectrally and relative to other sounds), its noticeability, the expectation of the consumer, and finally their emotional response. In the second phase, quantitative semantic differential listening studies were carried out using a vehicle simulator. Four principal components were found to explain 85% of the total variance of nine semantic scales: how intrusive the subjects believed the sound to be, how aggressive the aeroacoustic noises were, whether the sounds met the subjects expectation, and finally whether the sounds were perceived as spatially balanced by the participant. This study confirms that traditional aeroacoustic performance quantification methods employed by automotive manufacturers, may not be suitable for evaluating a number of the key factors of aeroacoustic sound quality perception. The study also demonstrates the use of a vehicle simulator to assess individual acoustic sources in the presence of other sounds

Osteoarthritis: a narrative review of molecular approaches to disease management

Osteoarthritis (OA) is a chronic, progressive degenerative whole joint disease that affects the articular cartilage, subchondral bone, ligaments, capsule, and synovium. While it is still believed to be a mechanically driven disease, the role of underlying co-existing inflammatory processes and mediators in the onset of OA and its progression is now more appreciated. Post-traumatic osteoarthritis (PTOA) is a subtype of OA that occurs secondary to traumatic joint insults and is widely used in pre-clinical models to help understand OA in general. There is an urgent need to develop new treatments as the global burden is considerable and expanding. In this review, we focus on the recent pharmacological advances in the treatment of OA and summarize the most significant promising agents based on their molecular effects. Those are classified here into broad categories: anti-inflammatory, modulation of the activity of matrix metalloproteases, anabolic, and unconventional pleiotropic agents. We provide a comprehensive analysis of the pharmacological advances in each of these areas and highlight future insights and directions in the OA field

Oxytocin Facilitates Social Learning by Promoting Conformity to Trusted Individuals

There is considerable interest in the role of the neuropeptide oxytocin in promoting social cohesion both in terms of promoting specific social bonds and also more generally for increasing our willingness to trust others and/or to conform to their opinions. These latter findings may also be important in the context of a modulatory role for oxytocin in improving the efficacy of behavioral therapy in psychiatric disorders. However, the original landmark studies claiming an important role for oxytocin in enhancing trust in others, primarily using economic game strategies, have been questioned by subsequent meta-analytic approaches or failure to reproduce findings in different contexts. On the other hand, a growing number of studies have consistently reported that oxytocin promotes conformity to the views of groups of in-group individuals. Most recently we have found that oxytocin can increase acceptance of social advice given by individual experts without influencing their perceived trustworthiness per se, but that increased conformity in this context is associated with how much an expert is initially trusted and liked. Oxytocin can also enhance the impact of information given by experts by facilitating expectancy and placebo effects. Here we therefore propose that a key role for oxytocin is not in facilitating social trust per se but in conforming to, and learning from, trusted individuals who are either in-group members and/or perceived experts. The implications of this for social learning and use of oxytocin as an adjunct to behavioral therapy in psychiatric disorders are discussed

Temperature-induced viral resistance in Emiliania huxleyi (Prymnesiophyceae)

© The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS One 9 (2014): e112134, doi:10.1371/journal.pone.0112134.Annual Emiliania huxleyi blooms (along with other coccolithophorid species) play important roles in the global carbon and sulfur cycles. E. huxleyi blooms are routinely terminated by large, host-specific dsDNA viruses, (Emiliania huxleyi Viruses; EhVs), making these host-virus interactions a driving force behind their potential impact on global biogeochemical cycles. Given projected increases in sea surface temperature due to climate change, it is imperative to understand the effects of temperature on E. huxleyi’s susceptibility to viral infection and its production of climatically active dimethylated sulfur species (DSS). Here we demonstrate that a 3°C increase in temperature induces EhV-resistant phenotypes in three E. huxleyi strains and that successful virus infection impacts DSS pool sizes. We also examined cellular polar lipids, given their documented roles in regulating host-virus interactions in this system, and propose that alterations to membrane-bound surface receptors are responsible for the observed temperature-induced resistance. Our findings have potential implications for global biogeochemical cycles in a warming climate and for deciphering the particular mechanism(s) by which some E. huxleyi strains exhibit viral resistance.This study was supported by funding from the National Science Foundation (OCE-1061883 to KDB, BVM, and OCE-1061876 to GRD) and in part by grants from The Gordon and Betty Moore Foundation (to BVM and KDB)

Neural, electrophysiological and anatomical basis of brain-network variability and its characteristic changes in mental disorders

Functional brain networks demonstrate significant temporal variability and dynamic reconfiguration even in the resting state. Currently, most studies investigate temporal variability of brain networks at the scale of single (micro) or whole-brain (macro) connectivity. However, the mechanism underlying time-varying properties remains unclear, as the coupling between brain network variability and neural activity is not readily apparent when analysed at either micro or macroscales. We propose an intermediate 15 (meso) scale analysis and characterize temporal variability of the functional architecture associated with a particular region. This yields a topography of variability that reflects the whole-brain and, most importantly, creates an analytical framework to establish the fundamental relationship between variability of regional functional architecture and its neural activity or structural connectivity. We find that temporal variability reflects the dynamical reconfiguration of a brain region into distinct functional modules at different times and may be indicative of brain flexibility and adaptability. Primary and unimodal sensory-motor cortices demon- 20 strate low temporal variability, while transmodal areas, including heteromodal association areas and limbic system, demonstrate the high variability. In particular, regions with highest variability such as hippocampus/parahippocampus, inferior and middle temporal gyrus, olfactory gyrus and caudate are all related to learning, suggesting that the temporal variability may indicate the level of brain adaptability. With simultaneously recorded electroencephalography/functional magnetic resonance imaging and functional magnetic resonance imaging/diffusion tensor imaging data, we also find that variability of regional functional architec- 25 ture is modulated by local blood oxygen level-dependent activity and a-band oscillation, and is governed by the ratio of intra- to inter-community structural connectivity. Application of the mesoscale variability measure to multicentre datasets of three mental disorders and matched controls involving 1180 subjects reveals that those regions demonstrating extreme, i.e. highest/lowest variability in controls are most liable to change in mental disorders. Specifically, we draw attention to the identification of diametrically opposing patterns of variability changes between schizophrenia and attention deficit hyperactivity disorder/autism. 30 Regions of the default-mode network demonstrate lower variability in patients with schizophrenia, but high variability in patients with autism/attention deficit hyperactivity disorder, compared with respective controls. In contrast, subcortical regions, especially the thalamus, show higher variability in schizophrenia patients, but lower variability in patients with attention deficit hyperactivity disorder. The changes in variability of these regions are also closely related to symptom scores. Our work provides insights into the dynamic organization of the resting brain and how it changes in brain disorders. The nodal variability measure may also be 35 potentially useful as a predictor for learning and neural rehabilitation

From Atoms to Cells:Multiscale Modeling of LiNi_xMn_yCo_zO₂Cathodes for Li-Ion Batteries

First-generation cathodes for commercial lithium-ion batteries are based on layered transition-metal oxides. Research on ternary compounds, such as LiCoO2, evolved into mixed-metal systems, notably Li(Ni,Mn,Co)O2 (NMCs), which allows significant tuning of the physical properties. Despite their widespread application in commercial devices, the fundamental understanding of NMCs is incomplete. Here, we review the latest insights from multiscale modeling, bridging between the redox phenomena that occur at an atomistic level to the transport of ions and electrons across an operating device. We discuss changes in the electronic and vibrational structures through the NMC compositional space and how these link to continuum models of electrochemical charge-discharge cycling. Finally, we outline the remaining challenges for predictive models of high-performance batteries, including capturing the relevant device bottlenecks and chemical degradation processes, such as oxygen evolution. </p

The COMT Val158Met Polymorphism and Reaction to a Transgression: Findings of Genetic Associations in Both Chinese and German Samples

After a transgression, people often either tend to avoid the transgressor or seek revenge. These tendencies can be investigated via a trait approach and surprisingly little is known about their biological underpinnings. One promising candidate gene polymorphism, which may influence individual differences in avoidance of a transgressor and vengefulness, is the COMT Val158Met (rs4680) polymorphism known to affect dopaminergic signaling and among others brain activity in situations in which people punish others for their behavior. We therefore investigated the molecular genetics of individual differences in Avoidance Motivation and vengefulness with a focus on this polymorphism. Possible genetic associations were first investigated in a sample of N = 730 Chinese participants (n = 196 females) using buccal cells to extract the DNA for genotyping. To replicate the findings we carried out a parallelized investigation in a sample of N = 585 German participants (n = 399 females). Chinese and German versions of the TRIM-12 and the Vengeance Scale were implemented to assess individual differences in tendencies to react to a transgression. Results show that Met allele carriers of the COMT Val158Met polymorphism (Val/Met and Met/Met) score significantly higher on the tendency to avoid a transgressor in the Chinese male and female samples, with an especially pronounced effect in the female subgroup. The same effect could be found in the German sample, again especially in females. Additionally, carrying a Met allele was associated with higher vengefulness in the Chinese sample only, especially in males. The present findings indicate that the COMT Val158Met polymorphism might influence individual differences in the motivation to avoid transgressors across cultures, especially in females. However, its association with vengefulness seems to be more complex and may exhibit some cultural and gender specific effects

The 2010 Maule, Chile earthquake: Downdip rupture limit revealed by space geodesy

Radar interferometry from the ALOS satellite captured the coseismic ground deformation associated with the 2010 Mw 8.8 Maule, Chile earthquake. The ALOS interferograms reveal a sharp transition in fringe pattern at ~150 km from the trench axis that is diagnostic of the downdip rupture limit of the Maule earthquake. An elastic dislocation model based on ascending and descending ALOS interferograms and 13 near-field 3-component GPS measurements reveals that the coseismic slip decreases more or less linearly from a maximum of 17 m (along-strike average of 6.5 m) at 18 km depth to near zero at 43–48 km depth, quantitatively indicating the downdip limit of the seismogenic zone. The depth at which slip drops to near zero appears to be at the intersection of the subducting plate with the continental Moho. Our model also suggests that the depth where coseismic slip vanishes is nearly uniform along the strike direction for a rupture length of ~600 km. The average coseismic slip vector and the interseismic velocity vector are not parallel, which can be interpreted as a deficit in strike-slip moment release