Phytoplankton realized Niches Track changing oceanic conditions at a long-term coastal station offSydney Australia

© 2018 Ajani, McGinty, Finkel and Irwin. Phytoplankton dynamics are closely linked to the ocean-climate system with evidence that changing ocean conditions are substantially altering phytoplankton biogeography, abundance and phenology. Using phytoplankton community composition and environmental data spanning 1965 to 2013 from a long-term Pacific Ocean coastal station offshore from Sydney, Australia (Port Hacking 100 m), we used the Maximum Entropy Modelling framework (MaxEnt) to test whether phytoplankton realized niches are fixed or shift in response to changing environmental conditions. The mean niches of phytoplankton closely tracked changes in mean temperature, while the mean salinity and mixed layer depth realized niches were consistently at the extreme range of available conditions. Prior studies had shown a fixed niche for nitrate in some phytoplankton species at a site where nitrate concentration was decreasing and potentially limiting; however, at Port Hacking nitrate and silicate niches increased more rapidly than environmental conditions, apparently in response to periodic occurrences of elevated nutrient concentrations. This study provides further evidence that climate change model projections cannot assume fixed realized niches of biotic communities, whilst highlighting the importance of sustained ocean measurements from the southern hemisphere to enhance our understanding of global ocean trends

Business model innovation for green urban infrastructure

Ph. D. ThesisIncreasing population density, air pollution, and climate change put pressure on urban areas. Green infrastructure (GI) is increasingly recognised as a means to address these issues. However, piecemeal and asset-focused delivery, can limit the realisation of potential benefits. The vision for a comprehensive GI network which functions as a true interconnected infrastructure system, is one delivered at city-scale with an overarching strategic plan. Existing approaches are inadequate to deliver this, due to the lack of effective business models to join up stakeholders and value streams. Using a case study of Newcastle upon Tyne, UK, this thesis shows that new and innovative business models (plans for how a GI system is delivered, who uses it and how it is financed and managed) are needed to enable the delivery of a city-scale GI vision. Effective business models for collaborative GI delivery will be where values (derived from benefit evaluation), stakeholders, and policy context intersect. The value of GI is its environmental, financial and social benefits to humans. Testing evaluation approaches finds that values should be weighted according to relevance, and that functionality across the whole system should be considered. The policy context informs the power and governance structures that underpin GI delivery. A power relationship analysis is used to identify key enablers, opportunities and barriers. In particular, local plans and policies have the greatest potential to support GI delivery demonstrating the need to create a GI strategy at city-scale. Stakeholders may supply or benefit from the GI, or both, and this circular relationship is a key opportunity for GI delivery. Where stakeholder interests intersect with GI values, the value proposition can be found; where they intersect with the policy context will be the power-holders and governance bodies needed to support GI delivery. Where the policy and values overlap are the key drivers for the project. This research found that working in the value-stakeholder-policy intersection, developing business models that use collaborative co-production approaches, provides the best opportunity to achieve the vision for an effective, interconnected and strategically delivered GI system

Visualising apoptosis in live zebrafish using fluorescence lifetime imaging with optical projection tomography to map FRET biosensor activity in space and time

Fluorescence lifetime imaging (FLIM) combined with optical projection tomography (OPT) has the potential to map Förster resonant energy transfer (FRET) readouts in space and time in intact transparent or near transparent live organisms such as zebrafish larvae, thereby providing a means to visualise cell signalling processes in their physiological context. Here the first application of FLIM OPT to read out biological function in live transgenic zebrafish larvae using a genetically expressed FRET biosensor is reported. Apoptosis, or programmed cell death, is mapped in 3-D by imaging the activity of a FRET biosensor that is cleaved by Caspase 3, which is a key effector of apoptosis. Although apoptosis is a naturally occurring process during development, it can also be triggered in a variety of ways, including through gamma irradiation. FLIM OPT is shown here to enable apoptosis to be monitored over time, in live zebrafish larvae via changes in Caspase 3 activation following gamma irradiation at 24 hours post fertilisation. Significant apoptosis was observed at 3.5 hours post irradiation, predominantly in the head region

Investment in epilepsy monitoring units improves epilepsy care-experience in a regional neuroscience centre

An evaluation of the clinical yield of inpatient long-term video-EEG (vEEG) in a new epilepsy monitoring unit (EMU) was undertaken, with findings compared to the centre's prior method of bedside vEEG recording in a standard neurology ward, as reported in 2004. A retrospective analysis of neurophysiology reports for all adults who underwent elective vEEG monitoring in the EMU at Cork University Hospital between January 2015 and July 2016 was conducted. Of 115 vEEG studies in the EMU, 100 (87.0%) were deemed diagnostically conclusive, 14 (12.2%) failed to catch any clinical events and showed normal EEG throughout, and one (0.9%) captured spells of unclear clinical significanceâ the corresponding figures reported in 2004 for bedside vEEGs were 21.3%, 77% and 1.6%, respectively. The EMU offers a more effective method of recording inpatient vEEG, which aids decision-making and improves clinical outcomes. Some evidence-based measures which could further enhance diagnostic yield are discussed

Cod response to past and current warm phases in the Seas of Iceland, a time series analysis

Climate change, and in particular global warming, is already affecting the Arctic and is expected to continue in the near future. A sustainable use the Arctic resources requires an increased understanding of its functioning that helps us anticipate change and adapt to it. Cod time series in Iceland cover a period of more than 50 years. Three distinct phases can be identified over this span of time: (1) the current warm phase characterised by relatively high cod biomasses, (2) an earlier phase (around the 1950s) with similar conditions separated by (3) some 20 years of cold temperatures and low biomasses. The aim of this study is to identify possible regime-dependent dynamics associated to these warm and cold phases that can help us identify key drivers in the current and future warm regime. To do this we compiled a database of fishing pressure, hydrographical and biological (copepods and euphausiids) variables as well as three cod population descriptors: (i) total spawning stock biomass, (ii) the population growth rate derived from matrix population models and (iii) disaggregated number at age time series. These three cod indices were subsequently regressed (GAM and threshold GAM) against the environmental and anthropogenic variables. Our results point out a probable regime-dependent mechanism where plankton effects would only be important for cod under warm conditions. No threshold-like responses were found in the population growth rate nor in the number at age for the various age classes

Modelling chemistry and biology after implantation of a drug-eluting stent. Part I: Drug transport

Drug-eluting stents have been used widely to prevent restenosis of arteries following percutaneous balloon angioplasty. Mathematical modelling plays an important role in optimising the design of these stents to maximise their efficiency. When designing a drug-eluting stent system, we expect to have a sufficient amount of drug being released into the artery wall for a sufficient period to prevent restenosis. In this paper, a simple model is considered to provide an elementary description of drug release into artery tissue from an implanted stent. From the model, we identified a parameter regime to optimise the system when preparing the polymer coating. The model provides some useful order of magnitude estimates for the key quantities of interest. From the model, we can identify the time scales over which the drug traverses the artery wall and empties from the polymer coating, as well as obtain approximate formulae for the total amount of drug in the artery tissue and the fraction of drug that has released from the polymer. The model was evaluated by comparing to in-vivo experimental data and good agreement was found

Development and resilience in three Arctic ecosystems: Baltic, Barents and Iceland Seas

In this GreenMAR project we look into the historical development of the marine ecosystems that surround the Nordic countries in an effort to forecast their future evolution. We pay particular attention to the way their food webs responded to similar stressors (warming) and fishing regimes in the past. We have compiled historical information on environmental and biological components, from plankton to fish, over the last 25 to 45 years, depending on the system. On these four ecosystems we have: (i) carried out multivariate analyses to describe their main trends and (ii) constructed stability landscapes to quantify their resilience. We will show these results and discuss their implications

Descriptive Analysis of a Baseline Concussion Battery Among U.S. Service Academy Members: Results from the Concussion Assessment, Research, and Education (CARE) Consortium

Introduction The prevalence and possible long-term consequences of concussion remain an increasing concern to the U.S. military, particularly as it pertains to maintaining a medically ready force. Baseline testing is being used both in the civilian and military domains to assess concussion injury and recovery. Accurate interpretation of these baseline assessments requires one to consider other influencing factors not related to concussion. To date, there is limited understanding, especially within the military, of what factors influence normative test performance. Given the significant physical and mental demands placed on service academy members (SAM), and their relatively high risk for concussion, it is important to describe demographics and normative profile of SAMs. Furthermore, the absence of available baseline normative data on female and non-varsity SAMs makes interpretation of post-injury assessments challenging. Understanding how individuals perform at baseline, given their unique individual characteristics (e.g., concussion history, sex, competition level), will inform post-concussion assessment and management. Thus, the primary aim of this manuscript is to characterize the SAM population and determine normative values on a concussion baseline testing battery. Materials and Methods All data were collected as part of the Concussion Assessment, Research and Education (CARE) Consortium. The baseline test battery included a post-concussion symptom checklist (Sport Concussion Assessment Tool (SCAT), psychological health screening inventory (Brief Symptom Inventory (BSI-18) and neurocognitive evaluation (ImPACT), Balance Error Scoring System (BESS), and Standardized Assessment of Concussion (SAC). Linear regression models were used to examine differences across sexes, competition levels, and varsity contact levels while controlling for academy, freshman status, race, and previous concussion. Zero inflated negative binomial models estimated symptom scores due to the high frequency of zero scores. Results Significant, but small, sex effects were observed on the ImPACT visual memory task. While, females performed worse than males (p < 0.0001, pη2 = 0.01), these differences were small and not larger than the effects of the covariates. A similar pattern was observed for competition level on the SAC. There was a small, but significant difference across competition level. SAMs participating in varsity athletics did significantly worse on the SAC compared to SAMs participating in club or intramural athletics (all p’s < 0.001, η2 = 0.01). When examining symptom reporting, males were more than two times as likely to report zero symptoms on the SCAT or BSI-18. Intramural SAMs had the highest number of symptoms and severity compared to varsity SAMs (p < 0.0001, Cohen’s d < 0.2). Contact level was not associated with SCAT or BSI-18 symptoms among varsity SAMs. Notably, the significant differences across competition level on SCAT and BSI-18 were sub-clinical and had small effect sizes. Conclusion The current analyses provide the first baseline concussion battery normative data among SAMs. While statistically significant differences may be observed on baseline tests, the effect sizes for competition and contact levels are very small, indicating that differences are likely not clinically meaningful at baseline. Identifying baseline differences and significant covariates is important for future concussion-related analyses to inform concussion evaluations for all athlete levels

Accelerated optical projection tomography applied to in vivo imaging of zebrafish

Optical projection tomography (OPT) provides a non-invasive 3-D imaging modality that can be applied to longitudinal studies of live disease models, including in zebrafish. Current limitations include the requirement of a minimum number of angular projections for reconstruction of reasonable OPT images using filtered back projection (FBP), which is typically several hundred, leading to acquisition times of several minutes. It is highly desirable to decrease the number of required angular projections to decrease both the total acquisition time and the light dose to the sample. This is particularly important to enable longitudinal studies, which involve measurements of the same fish at different time points. In this work, we demonstrate that the use of an iterative algorithm to reconstruct sparsely sampled OPT data sets can provide useful 3-D images with 50 or fewer projections, thereby significantly decreasing the minimum acquisition time and light dose while maintaining image quality. A transgenic zebrafish embryo with fluorescent labelling of the vasculature was imaged to acquire densely sampled (800 projections) and under-sampled data sets of transmitted and fluorescence projection images. The under-sampled OPT data sets were reconstructed using an iterative total variation-based image reconstruction algorithm and compared against FBP reconstructions of the densely sampled data sets. To illustrate the potential for quantitative analysis following rapid OPT data acquisition, a Hessian-based method was applied to automatically segment the reconstructed images to select the vasculature network. Results showed that 3-D images of the zebrafish embryo and its vasculature of sufficient visual quality for quantitative analysis can be reconstructed using the iterative algorithm from only 32 projections-achieving up to 28 times improvement in imaging speed and leading to total acquisition times of a few seconds

Diagnostic yield of routine EEG in adults with active epilepsy

Routine electroencephalogram (rEEG) is an important investigation in suspected seizures but can be normal in people with epilepsy. The diagnostic yield of rEEG varies considerably according to the patient group studied. We aimed to estimate the diagnostic yield of rEEG in a real-world cohort of adults with active epilepsyâ a population not previously reported. This single centre study evaluated neurophysiology findings for adults with prolonged inpatient video EEG (vEEG)-confirmed active epilepsy, who had at least one prior rEEG. Sixty-eight patients had a total of 171 rEEGs, of which 93 (54.4%) were normal, 42 (24.6%) found non-specific abnormalities and 36 (21.1%) captured interictal epileptiform abnormalities (IIEAs). Serial rEEGs revealed a 22.1% yield of IIEAs on the first test, with the cumulative yield peaking at 33.8% on the fourth rEEG. This study adds to existing evidence regarding the limited diagnostic usefulness of serial rEEG in patients with active epilepsy