3,571 research outputs found

    Identifying changes in EEG information transfer during drowsy driving by transfer entropy

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    © 2015 Huang, Pal, Chuang and Lin. Drowsy driving is a major cause of automobile accidents. Previous studies used neuroimaging based approaches such as analysis of electroencephalogram (EEG) activities to understand the brain dynamics of different cortical regions during drowsy driving. However, the coupling between brain regions responding to this vigilance change is still unclear. To have a comprehensive understanding of neural mechanisms underlying drowsy driving, in this study we use transfer entropy, a model-free measure of effective connectivity based on information theory. We investigate the pattern of information transfer between brain regions when the vigilance level, which is derived from the driving performance, changes from alertness to drowsiness. Results show that the couplings between pairs of frontal, central, and parietal areas increased at the intermediate level of vigilance, which suggests that an enhancement of the cortico-cortical interaction is necessary to maintain the task performance and prevent behavioral lapses. Additionally, the occipital-related connectivity magnitudes monotonically decreases as the vigilance level declines, which further supports the cortical gating of sensory stimuli during drowsiness. Neurophysiological evidence of mutual relationships between brain regions measured by transfer entropy might enhance the understanding of cortico-cortical communication during drowsy driving

    Financial Liberalization, Growth, Productivity and Capital Accumulation: The Case of European Integration

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    In the present contribution, we concentrate on the process of financial liberalization in a specific context of European economic and monetary integration. We implement de facto and de jure measures of financial liberalization and find that formal aspects of financial openness generate a strongly positive impact on economic growth and its sources, productivity growth and capital accumulation. Moreover, there is evidence of a positive contribution to the process stemming from the EU membership, while no substantial effect comes from the euro adoption. Finally, we investigate the effects from financial integration on country groups within the EU

    Eigen-AD: Algorithmic Differentiation of the Eigen Library

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    In this work we present useful techniques and possible enhancements when applying an Algorithmic Differentiation (AD) tool to the linear algebra library Eigen using our in-house AD by overloading (AD-O) tool dco/c++ as a case study. After outlining performance and feasibility issues when calculating derivatives for the official Eigen release, we propose Eigen-AD, which enables different optimization options for an AD-O tool by providing add-on modules for Eigen. The range of features includes a better handling of expression templates for general performance improvements, as well as implementations of symbolically derived expressions for calculating derivatives of certain core operations. The software design allows an AD-O tool to provide specializations to automatically include symbolic operations and thereby keep the look and feel of plain AD by overloading. As a showcase, dco/c++ is provided with such a module and its significant performance improvements are validated by benchmarks.Comment: Updated with accepted version for ICCS 2020 conference proceedings. The final authenticated publication is available online at https://doi.org/10.1007/978-3-030-50371-0_51. See v1 for the original, extended preprint. 14 pages, 7 figure

    The influence of perfusion solution on renal graft viability assessment

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    BACKGROUND: Kidneys from donors after cardiac or circulatory death are exposed to extended periods of both warm ischemia and intra-arterial cooling before organ recovery. Marshall’s hypertonic citrate (HOC) and Bretschneider’s histidine-tryptophan-ketoglutarate (HTK) preservation solutions are cheap, low viscosity preservation solutions used clinically for organ flushing. The aim of the present study was to evaluate the effects of these two solutions both on parameters used in clinical practice to assess organ viability prior to transplantation and histological evidence of ischemic injury after reperfusion. METHODS: Rodent kidneys were exposed to post-mortem warm ischemia, extended intra-arterial cooling (IAC) (up to 2 h) with preservation solution and reperfusion with either Krebs-Hensleit or whole blood in a transplant model. Control kidneys were either reperfused directly after retrieval or stored in 0.9% saline. Biochemical, immunological and histological parameters were assessed using glutathione-S-transferase (GST) enzymatic assays, polymerase chain reaction and mitochondrial electron microscopy respectively. Vascular function was assessed by supplementing the Krebs-Hensleit perfusion solution with phenylephrine to stimulate smooth muscle contraction followed by acetylcholine to trigger endothelial dependent relaxation. RESULTS: When compared with kidneys reperfused directly post mortem, 2 h of IAC significantly reduced smooth muscle contractile function, endothelial function and upregulated vascular cellular adhesion molecule type 1 (VCAM-1) independent of the preservation solution. However, GST release, vascular resistance, weight gain and histological mitochondrial injury were dependent on the preservation solution used. CONCLUSIONS: We conclude that initial machine perfusion viability tests, including ischemic vascular resistance and GST, are dependent on the perfusion solution used during in situ cooling. HTK-perfused kidneys will be heavier, have higher GST readings and yet reduced mitochondrial ischemic injury when compared with HOC-perfused kidneys. Clinicians should be aware of this when deciding which kidneys to transplant or discard

    The Schistosomiasis Research Agenda—What Now?

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    [Extract] As relatively new schistosomiasis researchers, we awaited with eagerness the publication of the "Schistosomiasis Research Agenda" SRA) put forward by Colley and Secor in the December 2007 issue of PLoS Neglected Tropical Diseases [1]. The SRA is a comprehensive, well-organized list of research activities that reflects the impressive diversity of interests that make up current schistosomiasis research. Colley and Secor went to admirable lengths to solicit the interests of researchers the world over, with special efforts to solicit the opinions of scientists in countries or regions where schistosomiasis is endemic, such as Brazil, China, and Africa. Having attended some of these meetings (11th International Congress of Parasitology, held in Glasgow, United Kingdom in August 2006; and the 55th Annual Meeting of the American Society of Tropical Medicine and Hygiene, held in Atlanta, United States in November 2006) and received the emails, we are confident that the SRA indeed reflects the richness and breadth of current schistosomiasis research

    Exploring patients’ experience and perception of being diagnosed with bladder cancer: A mixed methods approach

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    OBJECTIVE: To determine patient experience and perception following a diagnosis of non-muscle invasive bladder cancer (NMIBC). PATIENT AND METHODS: Patients were part of a prospective multi-centre observational study recruiting patients with NMIBC for a urine biomarker study (DETECT II; ClinicalTrials.gov: NCT02781428). A mix methods approach comprising 1) the Brief Illness Perception Questionnaire (Brief IPQ) and 2) semi-structured interviews to explore patients' experience of experiencing haematuria, initial and subsequent experience with NMIBC diagnosis. Both assessments were completed at 6 months following NMIBC diagnosis. RESULTS: A total of 213 patients completed the Brief IPQ. Patients felt that they had minimal symptoms (median [IQR: 2 [0-5]) and were not particularly affected emotionally (3 [1-6]) with a minimal effect to their daily life (2 [0-5]). However, they remained concern about their cancer diagnosis (5 [3-8]) and felt that they had no personal control over the cancer (2 [2-5]) and believed that their illness would affect them for some time (6 [3-10]). A significant association with a lower personal control of the disease (p70 years of age. A high number of patients were uncertain about the cause of their bladder cancer diagnosis. Qualitative analysis found that at initial presentation of haematuria, most patients were not aware of the risk of bladder cancer. Patients were most anxious and psychologically affected between the interval of cystoscopy diagnosis and transurethral resection of bladder tumour (TURBT). Following TURBT, most patients were positive about their cancer prognosis. CONCLUSION: NMIBC patients have a poor perception of disease control and believe that their disease will continue over a prolonged period of time. This is particularly more pertinent in the elderly. Patients are most psychologically affected during the interval between cancer diagnosis following cystoscopy and tumour resection at TURBT. Further, health awareness about the causes of bladder cancer remained poor with a significant number of patients unaware of the cause of bladder cancer. Psychological support and prompt TURBT following bladder cancer diagnosis would help improve the mental health of patients with NMIBC

    Intrauterine environmental and genetic influences on the association between birthweight and cardiovascular risk factors: studies in twins as a means of testing the fetal origins hypothesis

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    Evidence has accumulated that low birthweight is associated with several risk factors for cardiovascular disease. However, it is not known whether or not these associations are due to a programmed response to intrauterine malnutrition or genetic factors influencing both birthweight and cardiovascular risk factors. Twin studies offer a unique opportunity to distinguish between intrauterine and genetic origins of the association between birthweight and cardiovascular risk. In our twin cohort, low birthweight was associated with insulin resistance, lower HDL and shorter height within both dizygotic and monozygotic twin pairs, suggesting that these associations are, at least in part, independent of genetic factors. In contrast, low birthweight was associated with blood pressure, total and LDL cholesterol, fibrinogen and sympathetic activation within dizygotic twin pairs, but not within monozygotic twin pairs. These differences between dizygotic and monozygotic twins suggest that these associations are, at least in part, due to genetic factors. Therefore, both intrauterine environmental and genetic factors appear to play a role in the association between birthweight and cardiovascular risk factors. In the future, strategies may be developed targeted at improving or preventing impaired intrauterine growth. However, the effects of interventions that comprise changes in environment within the normal range may be limited due to the possible important role of genetic factor

    Population-based analysis of ocular Chlamydia trachomatis in trachoma-endemic West African communities identifies genomic markers of disease severity.

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    BACKGROUND: Chlamydia trachomatis (Ct) is the most common infectious cause of blindness and bacterial sexually transmitted infection worldwide. Ct strain-specific differences in clinical trachoma suggest that genetic polymorphisms in Ct may contribute to the observed variability in severity of clinical disease. METHODS: Using Ct whole genome sequences obtained directly from conjunctival swabs, we studied Ct genomic diversity and associations between Ct genetic polymorphisms with ocular localization and disease severity in a treatment-naïve trachoma-endemic population in Guinea-Bissau, West Africa. RESULTS: All Ct sequences fall within the T2 ocular clade phylogenetically. This is consistent with the presence of the characteristic deletion in trpA resulting in a truncated non-functional protein and the ocular tyrosine repeat regions present in tarP associated with ocular tissue localization. We have identified 21 Ct non-synonymous single nucleotide polymorphisms (SNPs) associated with ocular localization, including SNPs within pmpD (odds ratio, OR = 4.07, p* = 0.001) and tarP (OR = 0.34, p* = 0.009). Eight synonymous SNPs associated with disease severity were found in yjfH (rlmB) (OR = 0.13, p* = 0.037), CTA0273 (OR = 0.12, p* = 0.027), trmD (OR = 0.12, p* = 0.032), CTA0744 (OR = 0.12, p* = 0.041), glgA (OR = 0.10, p* = 0.026), alaS (OR = 0.10, p* = 0.032), pmpE (OR = 0.08, p* = 0.001) and the intergenic region CTA0744-CTA0745 (OR = 0.13, p* = 0.043). CONCLUSIONS: This study demonstrates the extent of genomic diversity within a naturally circulating population of ocular Ct and is the first to describe novel genomic associations with disease severity. These findings direct investigation of host-pathogen interactions that may be important in ocular Ct pathogenesis and disease transmission

    Techniques for Arbuscular Mycorrhiza Inoculum Reduction

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    It is well established that arbuscular mycorrhizal (AM) fungi can play a significant role in sustainable crop production and environmental conservation. With the increasing awareness of the ecological significance of mycorrhizas and their diversity, research needs to be directed away from simple records of their occurrence or casual speculation of their function (Smith and Read 1997). Rather, the need is for empirical studies and investigations of the quantitative aspects of the distribution of different types and their contribution to the function of ecosystems. There is no such thing as a fungal effect or a plant effect, but there is an interaction between both symbionts. This results from the AM fungi and plant community size and structure, soil and climatic conditions, and the interplay between all these factors (Kahiluoto et al. 2000). Consequently, it is readily understood that it is the problems associated with methodology that limit our understanding of the functioning and effects of AM fungi within field communities. Given the ubiquous presence of AM fungi, a major constraint to the evaluation of the activity of AM colonisation has been the need to account for the indigenous soil native inoculum. This has to be controlled (i.e. reduced or eliminated) if we are to obtain a true control treatment for analysis of arbuscular mycorrhizas in natural substrates. There are various procedures possible for achieving such an objective, and the purpose of this chapter is to provide details of a number of techniques and present some evaluation of their advantages and disadvantages. Although there have been a large number of experiments to investigated the effectiveness of different sterilization procedures for reducing pathogenic soil fungi, little information is available on their impact on beneficial organisms such as AM fungi. Furthermore, some of the techniques have been shown to affect physical and chemical soil characteristics as well as eliminate soil microorganisms that can interfere with the development of mycorrhizas, and this creates difficulties in the interpretation of results simply in terms of possible mycorrhizal activity. An important subject is the differentiation of methods that involve sterilization from those focussed on indigenous inoculum reduction. Soil sterilization aims to destroy or eliminate microbial cells while maintaining the existing chemical and physical characteristics of the soil (Wolf and Skipper 1994). Consequently, it is often used for experiments focussed on specific AM fungi, or to establish a negative control in some other types of study. In contrast, the purpose of inoculum reduction techniques is to create a perturbation that will interfere with mycorrhizal formation, although not necessarily eliminating any component group within the inoculum. Such an approach allows the establishment of different degrees of mycorrhizal formation between treatments and the study of relative effects. Frequently the basic techniques used to achieve complete sterilization or just an inoculum reduction may be similar but the desired outcome is accomplished by adjustments of the dosage or intensity of the treatment. The ultimate choice of methodology for establishing an adequate non-mycorrhizal control depends on the design of the particular experiments, the facilities available and the amount of soil requiring treatment
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