1,054 research outputs found

    The vector innovation structural time series framework: a simple approach to multivariate forecasting

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    The vector innovation structural time series framework is proposed as a way of modelling a set of related time series. Like all multi-series approaches, the aim is to exploit potential inter-series dependencies to improve the fit and forecasts. A key feature of the framework is that the series are decomposed into common components such as trend and seasonal effects. Equations that describe the evolution of these components through time are used as the sole way of representing the inter-temporal dependencies. The approach is illustrated on a bivariate data set comprising Australian exchange rates of the UK pound and US dollar. Its forecasting capacity is compared to other common single- and multi-series approaches in an experiment using time series from a large macroeconomic database.Vector innovation structural time series, state space model, multivariate time series, exponential smoothing, forecast comparison, vector autoregression.

    Synthesis and cellular penetration properties of new phosphonium based cationic amphiphilic peptides

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    A new category of phosphonium based cationic amphiphilic peptides has been developed and evaluated as potential antimicrobial peptides and cell penetrating peptides. The required building blocks were conveniently accessible from cysteine and could be applied in a solid phase peptide synthesis protocol for incorporation into peptide sequences. Evaluation of the antimicrobial properties and cellular toxicity of these phosphonium based peptides showed that these ā€œsoftā€ cationic side-chain containing peptides have poor antimicrobial properties and most of them were virtually non toxic (on HEK cells tested at 256 and 512 Ī¼M) and non-haemolytic (on horse erythrocytes tested at 512 Ī¼M), hinting at an interesting potential application as cell penetrating peptides. This possibility was evaluated using fluorescent peptide derivatives and showed that these phosphonium based peptide derivatives were capable of entering HEK cells and depending on the sequence confined to specific cellular areas

    Towards preventing and managing conflict of interest in nutrition policy? An analysis of submissions to a consultation on a draft WHO tool

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    Background: With multi-stakeholder approaches central to efforts to address global health challenges, debates around conflict of interest (COI) are increasingly prominent. The World Health Organization (WHO) recently developed a proposed tool to support member states in preventing and managing COI in nutrition policy. We analysed responses to an online consultation to explore how actors from across sectors understand COI and the ways in which they use this concept to frame the terms of commercial sector engagement in health governance. Methods: Submissions from 44 Member States, international organisations, non-governmental organizations (NGOs), academic institutions and commercial sector actors were coded using a thematic framework informed by framing theory. Respondentsā€™ orientation to the tool aligned with two broad frames, ie, a ā€˜collaboration and partnershipā€™ frame that endorsed multi-stakeholder approaches and a ā€˜restricted engagementā€™ frame that highlighted core tensions between public health and food industry actors. Results: Responses to the WHO tool reflected contrasting conceptualisations of COI and implications for health governance. While most Member States, NGOs, and academic institutions strongly supported the tool, commercial sector organisations depicted it as inappropriate, unworkable and incompatible with the Sustainable Development Goals (SGDs). Commercial sector respondents advanced a narrow, individual-level understanding of COI, seen as adequately addressed by existing mechanisms for disclosure, and viewed the WHO tool as unduly restricting scope for private sector engagement in nutrition policy. In contrast, health-focused NGOs and several Member States drew on a more expansive understanding of COI that recognised scope for wider tensions between public health goals and commercial interests and associated governance challenges. These submissions mostly welcomed the tool as an innovative approach to preventing and managing such conflicts, although some NGOs sought broader exclusion of corporate actors from policy engagement. Conclusion: Submissions on the WHO tool illustrate how contrasting positions on COI are central to understanding broader debates in nutrition policy and across global health governance. Effective health governance requires greater understanding of how COI can be conceptualised and managed amid high levels of contestation on policy engagement with commercial sector actors. This requires both ongoing innovation in governance tools and more extensive conceptual and empirical research

    Port Protocols for Deadlock-Freedom of Component Systems

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    In component-based development, approaches for property verification exist that avoid building the global system behavior of the component model. Typically, these approaches rely on the analysis of the local behavior of fixed sized subsystems of components. In our approach, we want to avoid not only the analysis of the global behavior but also of the local behaviors of the components. Instead, we consider very small parts of the local behaviors called port protocols that suffice to verify properties.Comment: In Proceedings ICE 2010, arXiv:1010.530

    Comparison of ambient solvent extraction methods for the analysis of fatty acids in non-starch lipids of ļ¬‚our and starch

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    BACKGROUND: Lipids are minor components of ļ¬‚ours, but are major determinants of baking properties and end-product quality. To the best of our knowledge, there is no single solvent system currently known that efļ¬ciently extracts all non-starch lipids from all ļ¬‚ours without the risk of chemical, mechanical or thermal damage. This paper compares nine ambient solvent systems (monophasic and biphasic) with varying polarities: Bligh and Dyer (BD); modiļ¬ed Bligh and Dyer using HCl (BDHCL); modiļ¬ed BD using NaCl (BDNaCl); methanolā€“chloroformā€“hexane (3:2:1, v/v); Hara and Radin (hexaneā€“isopropanol, 3:2, v/v); water-saturated n-butanol; chloroform; methanol and hexane for their ability to extract total non-starch lipids (separated by lipid classes) from wheat ļ¬‚our (Triticum aestivum L.). Seven ambient extraction protocols were further compared for their ability to extract total non-starch lipids from three alternative samples: barley ļ¬‚our (Hordeum vulgare L.), maize starch (Zea mays L.) and tapioca starch (Manihot esculenta Crantz). RESULTS: For wheat ļ¬‚our the original BD method and those containing HCl or NaCl tended to extract the maximum lipid and a signiļ¬cant correlation between lipid extraction yield (especially the glycolipids and phospholipids) and the polarity of the solvent was observed. For the wider range of samples BD and BD HCl repeatedly offered the maximum extraction yield and using pooled standardized (by sample) data from all ļ¬‚ours, total non-starch lipid extraction yield was positively correlated with solvent polarity (r=0.5682,P<0.05) and water ratio in the solvent mixture (r=0.5299,P<0.05). CONCLUSION: In general, BD-based methods showed better extraction yields compared to methods without the addition of water and, most interestingly, there was much greater method dependence of lipid yields in the starches when compared to the ļ¬‚our samples, which is due to the differences in lipid proļ¬les between the two sample types (ļ¬‚ours and starches)

    Quantification of plaque stiffness by Brillouin microscopy in experimental thin cap fibroatheroma

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    Plaques vulnerable to rupture are characterized by a thin and stiff fibrous cap overlaying a soft lipid-rich necrotic core. The ability to measure local plaque stiffness directly to quantify plaque stress and predict rupture potential would be very attractive, but no current technology does so. This study seeks to validate the use of Brillouin microscopy to measure the Brillouin frequency shift, which is related to stiffness, within vulnerable plaques. The left carotid artery of an ApoE-/- mouse was instrumented with a cuff that induced vulnerable plaque development in nine weeks. Adjacent histological sections from the instrumented and control arteries were stained for either lipids or collagen content, or imaged with confocal Brillouin microscopy. Mean Brillouin frequency shift was 15.79Ā±0.09 GHz in the plaque compared with 16.24Ā±0.15 (p \u3c 0.002) and 17.16Ā±0.56 GHz (p \u3c 0.002) in the media of the diseased and control vessel sections, respectively. In addition, frequency shift exhibited a strong inverse correlation with lipid area of 20.67Ā±0.06 (p \u3c 0.01) and strong direct correlation with collagen area of 0.71Ā±0.15 (p \u3c 0.05). This is the first study, to the best of our knowledge, to apply Brillouin spectroscopy to quantify atherosclerotic plaque stiffness, which motivates combining this technology with intravascular imaging to improve detection of vulnerable plaques in patients
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