Intrinsically linked graphs and even linking number

We study intrinsically linked graphs where we require that every embedding of the graph contains not just a non-split link, but a link that satisfies some additional property. Examples of properties we address in this paper are: a two component link with lk(A,L) = k2^r, k not 0, a non-split n-component link where all linking numbers are even, or an n-component link with components L, A_i where lk(L,A_i) = 3k, k not 0. Links with other properties are considered as well. For a given property, we prove that every embedding of a certain complete graph contains a link with that property. The size of the complete graph is determined by the property in question.Comment: Published by Algebraic and Geometric Topology at http://www.maths.warwick.ac.uk/agt/AGTVol5/agt-5-55.abs.htm

SINGLE SPECIES VERSUS MULTIPLE SPECIES MODELS: THE ECONOMIC IMPLICATIONS

Ecologists frequently note the importance of modelling entire ecosystems rather than single species, but most bioeconomic models in the current literature focus on a single species. While the mathematical difficulty of multiple species may quickly become overwhelming, sometimes making the single species option necessary, it is important to recognise the significance of the single species assumption to the model results. In this paper, the authors address the economic significance of this assumption through the development of a multiple species model and demonstrate the importance of interrelationships and economic values to the survival of endangered species.Resource /Energy Economics and Policy,

On the Bacteriology of Septic Wounds.

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Hotspots and Coldspots: Household and village-level variation in orphanhood prevalence in rural Malawi

We explore the spatial distribution of orphans in two areas of Malawi. We first review pertinent themes in qualitative data collected in our research sites. Then, using spatial analysis, we show how positive and negative clusters of orphans—which we term orphanhood "hotspots" and "coldspots"—can be found at the village and sub-village levels. In the third and longest section of the paper, and using multilevel analyses with both simple and complex variance structures, we evaluate the relationship between the presence of orphans and a range of individual, household and village-level characteristics, including households' spatial relationship to each other and to other local sites of significance. This series of analyses shows that the most important covariates of orphan presence are the density of settlement, household size, and religious characteristics, with the latter measured simultaneously at both household and village-level. Other characteristics like education, reported mortality levels and HIV infection, are wholly unrelated to orphan prevalence at all analytic levels. Wealth and various spatial characteristics are only marginally associated with orphan prevalence. We conclude by reviewing some difficulties in explaining causal mechanisms underlying these observed relationships, and discussing conceptual, theoretical and programmatic implications.Africa, AIDS/HIV, Malawi, multilevel model, orphan prevalence, orphans, spatial analysis

How does pre-reduction MRI affect surgeon's behaviour when reducing Distraction-Flexion injuries of the cervical spine?

Includes abstract. Includes bibliographical references

Investigating cognitive effort and its role in control over Pavlovian bias

Effort is a key determinant of cognitive performance, particularly for processes involving cognitive control – without it, performance may be slow, inaccurate or biased. Related to this, decreased ability to exert effort has been implicated in the symptoms of conditions including depression and anxiety. In this thesis I investigate the role of effort in the specific case of control over Pavlovian biases. In the first two experimental chapters I examine whether Pavlovian biases are in principle modifiable, a necessary precondition for demonstrating that they are also controllable. Following a simple programme of behavioural training, participants showed reduced influence of Pavlovian biases on behaviour, a result which is consistent with increased cognitive control. In the third experimental chapter, I present a new task for measuring cognitive effort sensitivity, suitable in particular for individual differences research. Subsequently, in the final experimental chapter, I use this task to test directly the hypothesis that the strength of Pavlovian bias is influenced by effortful cognitive control. I present initial evidence that indeed willingness to exert effort and the strength of Pavlovian biases seem to be negatively correlated, while effort also seems to be negatively associated with both depression and anxiety symptoms. Finally, in a standalone theoretical chapter, I discuss the rationale for effort costs, which currently are not well understood; I introduce and extend two existing ideas from outside of neuroscience which I think may be informative in this regard. Overall this thesis extends our understanding of the link between effort and control, suggesting in particular that the expression of Pavlovian biases can be framed in terms of effort-based decision-making. Additionally, by introducing fresh ideas about the basis of cognitive effort costs, it is hoped that this thesis will provide stronger foundations on which experimental research on cognitive effort can be built in the future

Methylglyoxal induces platelet hyperaggregation and reduces thrombus stability by activating PKC and inhibiting PI3K/Akt pathway

Diabetes is characterized by a dysregulation of glucose homeostasis and platelets from patients with diabetes are known to be hyper-reactive and contribute to the accelerated development of vascular diseases. Since many of the deleterious effects of glucose have been attributed to its metabolite methylgyloxal (MG) rather than to hyperglycemia itself, the aim of the present study was to characterize the effects of MG on platelet function. Washed human platelets were pre-incubated for 15 min with MG and platelet aggregation, adhesion on matrix-coated slides and signaling (Western blot) were assessed ex vivo. In vivo, the effect of MG on thrombus formation was determined using the FeCl3-induced carotid artery injury model. MG potentiated thrombin-induced platelet aggregation and dense granule release, but inhibited platelet spreading on fibronectin and collagen. In vivo, MG accelerated thrombus formation but decreased thrombus stability. At the molecular level, MG increased intracellular Ca2+ and activated classical PKCs at the same time as inhibiting PI3K/Akt and the β3-integrin outside-in signaling. In conclusion, these findings indicate that the enhanced MG concentration measured in diabetic patients can directly contribute to the platelet dysfunction associated with diabetes characterized by hyperaggregability and reduced thrombus stability

In-situ electronics and communications for intelligent energy storage

Lithium-ion batteries are increasingly common in high-power, safety–critical applications such as aerospace, spaceflight, automotive and grid storage. The voltage and power specifications of such applications usually require large numbers of individual cells combined in series and parallel to form a battery pack. It is then the role of the Battery Management System (BMS) to monitor these cells condition and ensure they remain within safe operating limits. To minimise cost and complexity, it is typical to monitor only a fraction of the cells in a battery pack. This creates potential safety and reliability issues and requires conservative limits imposed on the overall system to ensure safe operation. This is insufficient in high-power, safety–critical applications and thus alternative approaches to battery management are required. Here we demonstrate the development of novel miniature electronic devices for incorporation in-situ at a cell-level during manufacture. This approach enables local cell-to-cell and cell-to-BMS data communication of sensor data without the need for additional wiring infostructure within a battery module assembly. The electronics firmware and hardware integration within the cell’s electrode stack is demonstrated to function after triggering post cell formation and through cycling and electrochemical impedance analysis. This work shows that the proposed approach has a negligible impact on the cells’ performance and highlights a new technique for active monitoring of the cell’s in-situ conditions. This research will enable new methods of cells characterization and monitoring for optimum electrochemical and thermal performance while improving system safety

Improving the clinical value and utility of CGM systems: issues and recommendations : a joint statement of the European Association for the Study of Diabetes and the American Diabetes Association Diabetes Technology Working Group

The first systems for continuous glucose monitoring (CGM) became available over 15 years ago. Many then believed CGM would revolutionise the use of intensive insulin therapy in diabetes; however, progress towards that vision has been gradual. Although increasing, the proportion of individuals using CGM rather than conventional systems for self-monitoring of blood glucose on a daily basis is still low in most parts of the world. Barriers to uptake include cost, measurement reliability (particularly with earlier-generation systems), human factors issues, lack of a standardised format for displaying results and uncertainty on how best to use CGM data to make therapeutic decisions. This scientific statement makes recommendations for systemic improvements in clinical use and regulatory (pre- and postmarketing) handling of CGM devices. The aim is to improve safety and efficacy in order to support the advancement of the technology in achieving its potential to improve quality of life and health outcomes for more people with diabetes