1,183 research outputs found

    Rifts in Spreading Wax Layers

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    We report experimental results on the rift formation between two freezing wax plates. The plates were pulled apart with constant velocity, while floating on the melt, in a way akin to the tectonic plates of the earth's crust. At slow spreading rates, a rift, initially perpendicular to the spreading direction, was found to be stable, while above a critical spreading rate a "spiky" rift with fracture zones almost parallel to the spreading direction developed. At yet higher spreading rates a second transition from the spiky rift to a zig-zag pattern occurred. In this regime the rift can be characterized by a single angle which was found to be dependent on the spreading rate. We show that the oblique spreading angles agree with a simple geometrical model. The coarsening of the zig-zag pattern over time and the three-dimensional structure of the solidified crust are also discussed.Comment: 4 pages, Postscript fil

    potential biomarkers of haemophilic arthropathy correlations with compatible additive magnetic resonance imaging scores

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    Introduction: Although biomarkers are useful diagnostic tools to assess joint damage in osteoarthritis and rheumatoid arthritis, few data exist for biomarkers of haemophilic arthropathy. Aim: To evaluate the association between biomarkers and compatible additive magnetic resonance imaging (MRI) scores in patients with severe haemophilia A. Methods: Patients aged 12–35 years with no history of factor VIII (FVIII) inhibitors were enrolled in a controlled, cross-sectional, multinational investigation. Patients received primary or secondary prophylaxis or on-demand treatment with FVIII and underwent MRI on four joints (two ankles, two knees). Soluble biomarkers of cartilage and bone degradation, inflammation, and angiogenesis were assessed (serum levels of C-terminal telopeptides of type I collagen [CTX-I], cartilage oligomeric matrix protein [COMP], chondroitin-sulphate aggrecan turnover 846 epitope [CS846], tissue inhibitor of metalloproteinase 1 [TIMP-1]; plasma levels of vascular endothelial growth factor [VEGF], matrix metalloproteinases 3 and 9 [MMP3, MMP9]). Relationships between biomarkers and MRI scores were evaluated using Spearman rank correlation. Results: Biomarkers were assessed in 117 of 118 per-protocol patients. Mean and median CTX-I, COMP, TIMP-1, MMP3, MMP9, and VEGF values were within normal ranges (reference range not available for CS846 in healthy volunteers). No correlations between biomarkers and MRI scores were found, with the exception of CS846, which showed significant correlation in a subgroup of 22 on-demand patients (r = 0.436; P = 0.04). Conclusions: Compatible additive MRI scores showed no clear correlations with any of the potential biomarkers for haemophilic arthropathy in the overall population. CS846 levels were significantly correlated with MRI scores in patients treated on demand. (Less

    A shared framework for the common mental disorders and Non-Communicable Disease: key considerations for disease prevention and control.

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    BACKGROUND: Historically, the focus of Non Communicable Disease (NCD) prevention and control has been cardiovascular disease (CVD), type 2 diabetes mellitus (T2DM), cancer and chronic respiratory diseases. Collectively, these account for more deaths than any other NCDs. Despite recent calls to include the common mental disorders (CMDs) of depression and anxiety under the NCD umbrella, prevention and control of these CMDs remain largely separate and independent. DISCUSSION: In order to address this gap, we apply a framework recently proposed by the Centers for Disease Control with three overarching objectives: (1) to obtain better scientific information through surveillance, epidemiology, and prevention research; (2) to disseminate this information to appropriate audiences through communication and education; and (3) to translate this information into action through programs, policies, and systems. We conclude that a shared framework of this type is warranted, but also identify opportunities within each objective to advance this agenda and consider the potential benefits of this approach that may exist beyond the health care system

    Experience with the introduction of dry, urine-diverting sanitation systems in Ethiopia

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    To overcome the drawbacks of conventional sanitation systems, new approaches to sanitation are necessary. Human faeces and urine as well as greywater represent potential resources requiring efficient management. Thus, source-separating systems, which safe water and allow the recycling of nutrients to agriculture, can provide an alternative. These systems can even be integrated into multistorey houses, therefore addressing the need for resource efficient sanitation in condominium housing programmes. Several urine separating facilities are implemented in Ethiopia showing a high acceptance by their users. The cost comparison between source-separating systems and the conventional system for condominium houses shows an advantage for the new approach due to savings of water for toilet flushing as well as reduced costs for the treatment of the wastewater in septic tanks. The use of human urine as fertiliser in several trials resulted in significant benefits in terms of improved crop growth

    Automated Segmentation of Intraretinal Cystoid Fluid in Optical Coherence Tomography

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    Cystoid macular edema (CME) is observed in a variety of ocular disorders and is strongly associated with vision loss. Optical coherence tomography (OCT) provides excellent visualization of cystoid fluid, and can assist clinicians in monitoring the progression of CME. Quantitative tools for assessing CME may lead to better metrics for choosing treatment protocols. To address this need, this paper presents a fully automated retinal cyst segmentation technique for OCT image stacks acquired from a commercial scanner. The proposed method includes a computationally fast bilateral filter for speckle denoising while maintaining CME boundaries. The proposed technique was evaluated in images from 16 patients with vitreoretinal disease and three controls. The average sensitivity and specificity for the classification of cystoid regions in CME patients were found to be 91% and 96%, respectively, and the retinal volume occupied by cystoid fluid obtained by the algorithm was found to be accurate within a mean and median volume fraction of 1.9% and 0.8%, respectively

    Adaptive servoventilation improves cardiac function and respiratory stability

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    Cheyne–Stokes respiration (CSR) in patients with chronic heart failure (CHF) is of major prognostic impact and expresses respiratory instability. Other parameters are daytime pCO2, VE/VCO2-slope during exercise, exertional oscillatory ventilation (EOV), and increased sensitivity of central CO2 receptors. Adaptive servoventilation (ASV) was introduced to specifically treat CSR in CHF. Aim of this study was to investigate ASV effects on CSR, cardiac function, and respiratory stability. A total of 105 patients with CHF (NYHA ≥ II, left ventricular ejection fraction (EF) ≤ 40%) and CSR (apnoea–hypopnoea index ≥ 15/h) met inclusion criteria. According to adherence to ASV treatment (follow-up of 6.7 ± 3.2 months) this group was divided into controls (rejection of ASV treatment or usage <50% of nights possible and/or <4 h/night; n = 59) and ASV (n = 56) adhered patients. In the ASV group, ventilator therapy was able to effectively treat CSR. In contrast to controls, NYHA class, EF, oxygen uptake, 6-min walking distance, and NT-proBNP improved significantly. Moreover, exclusively in these patients pCO2, VE/VCO2-slope during exercise, EOV, and central CO2 receptor sensitivity improved. In CHF patients with CSR, ASV might be able to improve parameters of SDB, cardiac function, and respiratory stability

    Cancer risk in HIV-infected individuals on HAART is largely attributed to oncogenic infections and state of immunocompetence

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    <p>Abstract</p> <p>Objectives</p> <p>To estimate the cancer risk of HIV-infected patients in the HAART era with respect to a general reference population and to determine risk factors for malignancy.</p> <p>Methods</p> <p>Long term (1996-2009) cancer incidence of the Bonn single centre HIV cohort was compared to the incidence of the reference population of Saarland using standardized incidence ratios (SIR). Poisson regression analysis was used to identify predictors of cancer risk.</p> <p>Results</p> <p>1,476 patients entered the cohort, enabling 8,772 person years of observation. 121 tumours in 114 patients, 7 in-situ and 114 invasive cancers, were identified. Malignancies associated with infectious agents such as Kaposi sarcoma (SIRs: male: 5,683; female: 277), non-Hodgkin lymphoma (SIRs male: 35; female: 18), anal cancer (SIRs male: 88; female: 115) as well a cervical carcinoma (SIR female: 4) and Hodgkin's disease (SIR male: 39) and liver cancer (SIR male: 18) were substantially more frequent in HIV-infected patients than in the general population (p < 0.001, each), whereas all other types of cancer were not increased. Poisson regression identified HAART (incidence rate ratio IRR (95% CI): 0.28 (0.19-0.41), p < 0.001), CD4 count (IRR per 100 cells/μl increase: 0.66 (0.57-0.76), p < 0.001), hepatitis B (IRR: 2.15 (1.10-4.20), p = 0.046) and age (IRR per 10 year increase: 1.23 (1.03 - 1.46), p = 0.023) as independent predictors for the occurrence of any type of cancer.</p> <p>Conclusions</p> <p>HAART and preserved CD4 cells preferentially reduce the risk of malignancies associated with oncogenic infections.</p

    Evidence from Identified Particles for Active Quark and Gluon Degrees of Freedom

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    Measurements of intermediate pT (1.5 < pT < 5.0 GeV/c) identified particle distributions in heavy ion collisions at SPS and RHIC energies display striking dependencies on the number of constituent quarks in the corresponding hadron. One finds that elliptic flow at intermediate pT follows a constituent quark scaling law as predicted by models of hadron formation through coalescence. In addition, baryon production is also found to increase with event multiplicity much faster than meson production. The rate of increase is similar for all baryons, and seemingly independent of mass. This indicates that the number of constituent quarks determines the multiplicity dependence of identified hadron production at intermediate pT. We review these measurements and interpret the experimental findings.Comment: 8 pages, 5 figures, proceedings for SQM2006 conference in Los Angele

    A Hedged Monte Carlo Approach to Real Option Pricing

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    In this work we are concerned with valuing optionalities associated to invest or to delay investment in a project when the available information provided to the manager comes from simulated data of cash flows under historical (or subjective) measure in a possibly incomplete market. Our approach is suitable also to incorporating subjective views from management or market experts and to stochastic investment costs. It is based on the Hedged Monte Carlo strategy proposed by Potters et al (2001) where options are priced simultaneously with the determination of the corresponding hedging. The approach is particularly well-suited to the evaluation of commodity related projects whereby the availability of pricing formulae is very rare, the scenario simulations are usually available only in the historical measure, and the cash flows can be highly nonlinear functions of the prices.Comment: 25 pages, 14 figure

    Influence of Agronomic and Climatic Factors on Fusarium Infestation and Mycotoxin Contamination of Cereals in Norway

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    A total of 602 samples of organically and conventionally grown barley, oats and wheat was collected at grain harvest during 2002–2004 in Norway. Organic and conventional samples were comparable pairs regarding cereal species, growing site and harvest time, and were analysed for Fusarium mould and mycotoxins. Agronomic and climatic factors explained 10–30% of the variation in Fusarium species and mycotoxins. Significantly lower Fusarium infestation and concentrations of important mycotoxins were found in the organic cereals. The mycotoxins deoxynivalenol (DON) and HT-2 toxin (HT-2) constitute the main risk for human and animal health in Norwegian cereals. The impacts of various agronomic and climatic factors on DON and HT-2 as well as on their main producers F. graminearum and F. langsethiae and on total Fusarium were tested by multivariate statistics. Crop rotation with non-cereals was found to reduce all investigated characteristics significantly – mycotoxin concentrations as well as various Fusarium infestations. No use of mineral fertilisers and herbicides was also found to decrease F. graminearum, whereas lodged fields increased the occurrence of this species. No use of herbicides was also found to decrease F. langsethiae, but for this species the occurrence was lower in lodged fields. Total Fusarium infestation was decreased with no use of fungicides or mineral fertilisers, and with crop rotation, as well as by using herbicides and increased by lodged fields. Clay and to some extent silty soils seemed to reduce F. graminearum in comparison with sandy soils. Concerning climate factors, low temperature before grain harvest was found to increase DON; and high air humidity before harvest to increase HT-2. F. graminearum was negatively correlated with precipitation in July but correlated with air humidity before harvest. F. langsethiae was correlated with temperature in July. Total Fusarium increased with increasing precipitation in July. Organic cereal farmers have fewer cereal intense rotations than conventional farmers. Further, organic farmers do not apply mineral fertiliser or pesticides (fungicides, herbicides or insecticides), and have less problem with lodged fields. The study showed that these agronomic factors were related to the infestation of Fusarium species and the concentration of mycotoxins. Hence, it is reasonable to conclude that farming system (organic versus conventional) impacts Fusarium infestation, and that organic management tends to reduce Fusarium and mycotoxins. However, Fusarium infestation and mycotoxin concentrations may be influenced by a range of factors not studied here, such as local topography and more local climate, as well as cereal species and variety
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