636 research outputs found

    THE CHANGING OF ROWING TECHNIQUE AS A FUNCTION OF EXERTION

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    In our paper we examine the effect of the added exertion on the changing of technique in the rowing motion under laboratory conditions, usin4 an ergometer. The Hungarian National Junior team of four helped us at the examinations, which consisted of an anthropometrical measurement and five steps of exertion on the rowing ergometer, where the spreading of the motions during the exertion period was determined by a computer (SELSPOT system), meanwhile the level of tiredness by the measurement of pulse and the acidity of blood in the intervals between these periods. The comparison of the levels of tiredness shown by the physiological characteristics and of the changings in the motion of rowing can help us not only in the detection of unique errors, but also of some constant technical ones, which are dealt with thoroughly in my lecture

    Towards sex-specific osteoarthritis risk models: evaluation of risk factors for knee osteoarthritis in males and females

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    Objectives The aim of this study was to identify sex-specific prevalence and strength of risk factors for the incidence of radiographic knee OA (incRKOA). Methods Our study population consisted of 10 958 Rotterdam Study participants free of knee OA in one or both knees at baseline. One thousand and sixty-four participants developed RKOA after a median follow-up time of 9.6 years. We estimated the association between each available risk factor and incRKOA using sex stratified multivariate regression models with generalized estimating equations. Subsequently, we statistically tested sex differences between risk estimates and calculated the population attributable fractions (PAFs) for modifiable risk factors. Results The prevalence of the investigated risk factors was, in general, higher in women compared with men, except that alcohol intake and smoking were higher in men and high BMI showed equal prevalence. We found significantly different risk estimates between men and women: high level of physical activity [relative risk (RR) 1.76 (95% CI: 1.29–2.40)] or a Kellgren and Lawrence score 1 at baseline [RR 5.48 (95% CI: 4.51–6.65)] was higher in men. Among borderline significantly different risk estimates was BMI ≥27, associated with higher risk for incRKOA in women [RR 2.00 (95% CI: 1.74–2.31)]. The PAF for higher BMI was 25.6% in women and 19.3% in men. Conclusion We found sex-specific differences in both presence and relative risk of several risk factors for incRKOA. Especially BMI, a modifiable risk factor, impacts women more strongly than men. These risk factors can be used in the development of personalized prevention strategies and in building sex-specific prediction tools to identify high risk profile patients

    Nanocomposite-based dual enzyme system for broad-spectrum scavenging of reactive oxygen species

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    A broad-spectrum reactive oxygen species (ROS)-scavenging hybrid material (CASCADE) was developed by sequential adsorption of heparin (HEP) and poly(L-lysine) (PLL) polyelectrolytes together with superoxide dismutase (SOD) and horseradish peroxidase (HRP) antioxidant enzymes on layered double hydroxide (LDH) nanoclay support. The synthetic conditions were optimized so that CASCADE possessed remarkable structural (no enzyme leakage) and colloidal (excellent resistance against salt-induced aggregation) stability. The obtained composite was active in decomposition of both superoxide radical anions and hydrogen peroxide in biochemical assays revealing that the strong electrostatic interaction with the functionalized support led to high enzyme loadings, nevertheless, it did not interfere with the native enzyme conformation. In vitro tests demonstrated that ROS generated in human cervical adenocarcinoma cells were successfully consumed by the hybrid material. The cellular uptake was not accompanied with any toxicity effects, which makes the developed CASCADE a promising candidate for treatment of oxidative stress-related diseases

    Development of a Synthetic Floral Lure for Pollen Beetles (Coleoptera: Nitidulidae)

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    Pollen beetles (Coleoptera: Nitidulidae) rank among the most important pests of oilseed rape (Brassica napus). For their timely detection in early spring, yellow sticky or water pan traps are used; however, it has been suggested that the addition of chemical lures to attractive visual cues could improve trap efficacy. During the course of field trials in Hungary, we have developed a 3-component synthetic floral lure consisting of (E)-anethol Ăľ (E)-cinnamyl alcohol Ăľ (E)-cinnamyl acetate, which attracted large numbers of pollen beetles into large capture-capacity fluorescent yellow funnel traps. There was no apparent difference between the pollen beetle species Brassicogethes aeneus F. 1775 (earlier Meligethes aeneus), Brassicogethes viridescens F. 1775, Brassicogethes coracinus Sturm 1845 and Fabogethes nigrescens Sturm 1845 in their responses to the 3-component lure, which can therefore be used to trap all of them. Funnel traps with the new ternary floral lure were more efficient in catching beetles than those with lures containing 2-phenethyl isothiocyanate, a previously described plant-derived attractant for pollen beetles. However, the effect of the addition of the isothiocyanate to the ternary blend was not completely clear from these experiments and thus requires further studies

    Fundamental properties and applications of quasi-local black hole horizons

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    The traditional description of black holes in terms of event horizons is inadequate for many physical applications, especially when studying black holes in non-stationary spacetimes. In these cases, it is often more useful to use the quasi-local notions of trapped and marginally trapped surfaces, which lead naturally to the framework of trapping, isolated, and dynamical horizons. This framework allows us to analyze diverse facets of black holes in a unified manner and to significantly generalize several results in black hole physics. It also leads to a number of applications in mathematical general relativity, numerical relativity, astrophysics, and quantum gravity. In this review, I will discuss the basic ideas and recent developments in this framework, and summarize some of its applications with an emphasis on numerical relativity.Comment: 14 pages, 2 figures. Based on a talk presented at the 18th International Conference on General Relativity and Gravitation, 8-13 July 2007, Sydney, Australi

    How Should We Measure? A Review of Circular Cities Indicators

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    As the world continues to urbanize, it is necessary to identify and implement new urban development models and strategies in order to meet the challenges of sustainable development. As cities continue to face challenges in becoming fully circular, the need to establish a framework to measure the circular economy in urban areas grows. Many definitions for circular cities have been developed and addressed in recent years, as have numerous indicators. To make the transition to a circular city, we must integrate the findings and develop a general definition and measurement framework. This article aims at outlining a framework for circular cities indicators based on their key characteristics, as well providing directions for fostering circularity at the city level. To accomplish this goal, we conducted a systematic review and analyzed key papers published in the field of circular economy to determine how circular cities are measured. Choosing the right indicators to use for developing, monitoring, and evaluating circular cities is a difficult task for urban policymakers, managers, and planners. This highlights the significance of standardized frameworks for urban indicators. As a result, the authors propose a framework and highlight some key points about circular cities and smart urban metabolism

    Catches of Euxoa tritici in pheromone traps for Anarsia lineatella are due to the presence of (Z)-5-decenyl acetate as an impurity

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    Traps baited with the synthetic pheromone of Anarsia lineatella Zeller (Lepidoptera: Gelechiidae) frequently captured also Euxoa tritici L. males (Lepidoptera: Noctuidae) in field tests in Hungary. As (E)-monounsaturated compounds are uncommon among sex attractants or pheromone components of Noctuidae, it was hypothesized that the Euxoa catches may have been due to impurities of the (Z) isomer in synthetic (E)-5-decenyl acetate, which is the major component in the pheromone lure of A. lineatella. Traps baited with synthetic (Z)-5-decenyl acetate captured large numbers of E. tritici, and the compound showed a clear dose–response effect. Reanalysis of the synthetic batch of (E)-5-decenyl acetate used in preparation of the A. lineatella lure showed the presence of 10% of the (Z) isomer. Traps baited with synthetic (Z)-5-decenyl acetate can be used in the future for detection and monitoring purposes of E. tritici, a widely distributed pest of cereals and other field crops. The compound also showed attraction of Euxoa seliginis Duponche

    Numerical relativity with characteristic evolution, using six angular patches

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    The characteristic approach to numerical relativity is a useful tool in evolving gravitational systems. In the past this has been implemented using two patches of stereographic angular coordinates. In other applications, a six-patch angular coordinate system has proved effective. Here we investigate the use of a six-patch system in characteristic numerical relativity, by comparing an existing two-patch implementation (using second-order finite differencing throughout) with a new six-patch implementation (using either second- or fourth-order finite differencing for the angular derivatives). We compare these different codes by monitoring the Einstein constraint equations, numerically evaluated independently from the evolution. We find that, compared to the (second-order) two-patch code at equivalent resolutions, the errors of the second-order six-patch code are smaller by a factor of about 2, and the errors of the fourth-order six-patch code are smaller by a factor of nearly 50.Comment: 12 pages, 5 figures, submitted to CQG (special NFNR issue

    The discrete energy method in numerical relativity: Towards long-term stability

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    The energy method can be used to identify well-posed initial boundary value problems for quasi-linear, symmetric hyperbolic partial differential equations with maximally dissipative boundary conditions. A similar analysis of the discrete system can be used to construct stable finite difference equations for these problems at the linear level. In this paper we apply these techniques to some test problems commonly used in numerical relativity and observe that while we obtain convergent schemes, fast growing modes, or ``artificial instabilities,'' contaminate the solution. We find that these growing modes can partially arise from the lack of a Leibnitz rule for discrete derivatives and discuss ways to limit this spurious growth.Comment: 18 pages, 22 figure
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