1,098 research outputs found

    Analisis Miskonsepsi Siswa Kelas XI SMA Pada Materi Larutan Penyangga Menggunakan Instrumen Tes Three Tier Multiple Choice

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    The research is aimed to analyze misconceptions of high school students of class XI on the buffer solution material using instruments Three Tier Multiple Choice Tests. Another purpose of this study was to determine the percentage of student misconceptions and location misconceptions on chemical material especially on the subject of buffer solution. The research method is descriptive, data collection by giving a 13 item multiple choice questions with closed reason and CRI index and then the results of each items students answer were analyzed. The results of this study are misconceptions in chemistry learning especially in a buffer solution dispersed in of all concepts. The most common misconceptions on the working principle of the buffer solution by 51% and the lowest on the properties of the buffer solution by 31%. Suggestions put forward is the need to hold further research to uncover misconceptions where they come from and how to overcome these misconceptions

    Galactic Binary Gravitational Wave Noise within LISA Frequency Band

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    Gravitational wave noise associated with unresolved binary stars in the Galaxy is studied with the special aim of determining the upper frequency at which it stops to contribute at the rms noise level of the proposed space-born interferometer (LISA). The upper limit to this background is derived from the statistics of SN Ia explosions, part of which can be triggered by binary white dwarf coalescences. The upper limiting frequency at which binary stochastic noise crosses LISA rms sensitivity is found to lie within the range 0.03-0.07 Hz, depending on the galactic binary white dwarf coalescence rate. To be reliably detectable by LISA, the energy density of relic cosmological background per logarithmic frequency interval should be Omega_{GW}h_{100}^2>10^{-8} at f>0.03 Hz.Comment: 16 pages with 1 eps figure, aasms4.sty, to appear in the ApJ vol. 494 February 20, 1998 issu

    Sudden cardiac death in anabolic-androgenic steroid users: A literature review

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    Background and objectives: Anabolic-androgenic steroids (AASs) are a group of synthetic molecules derived from testosterone and its related precursors. AASs are widely used illicitly by adolescents and athletes, especially by bodybuilders, both for aesthetic uses and as performance enhancers to increase muscle growth and lean body mass. When used illicitly they can damage health and cause disorders affecting several functions. Sudden cardiac death (SCD) is the most common medical cause of death in athletes. SCD in athletes has also been associated with the use of performance-enhancing drugs. This review aimed to focus on deaths related to AAS abuse to investigate the cardiac pathophysiological mechanism that underlies this type of death, which still needs to be fully investigated. Materials and Methods: This review was conducted using PubMed Central and Google Scholar databases, until 21 July 2020, using the following key terms: “((Sudden cardiac death) OR (Sudden death)) AND ((androgenic anabolic steroid) OR (androgenic anabolic steroids) OR (anabolic-androgenic steroids) OR (anabolic-androgenic steroid))”. Thirteen articles met the inclusion and exclusion criteria, for a total of 33 reported cases. Results: Of the 33 cases, 31 (93.9%) were males while only 2 (61%) were females. Mean age was 29.79 and, among sportsmen, the most represented sports activity was bodybuilding. In all cases there was a history of AAS abuse or a physical phenotype suggesting AAS use; the total usage period was unspecified in most cases. In 24 cases the results of the toxicological analysis were reported. The most detected AASs were nandrolone, testosterone, and stanozolol. The most frequently reported macroscopic alterations were cardiomegaly and left ventricular hypertrophy, while the histological alterations were foci of fibrosis and necrosis of the myocardial tissue. Conclusions: Four principal mechanisms responsible for SCD have been proposed in AAS abusers: the atherogenic model, the thrombosis model, the model of vasospasm induced by the release of nitric oxide, and the direct myocardial injury model. Hypertrophy, fibrosis, and necrosis represent a substrate for arrhythmias, especially when combined with exercise. Indeed, AAS use has been shown to change physiological cardiac remodeling of athletes to pathophysiological cardiac hypertrophy with an increased risk of life-threatening arrhythmias

    Improving resilience management for critical infrastructures\u2014strategies and practices across air traffic management and healthcare

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    Recent natural and man-made disasters highlight that a more resilient approach to preparing for and dealing with such events is needed. To address this challenge, the main objective of the research and innovation H2020 project DARWIN is the development of European resilience management guidelines for Critical Infrastructures (CI). Based on a systematic literature survey with a world-wide scope and prioritization of resilience concepts, the guidelines have been developed taking into account everyday operations, contingency plans, training, etc. This paper describes insights gained from the adaptation of these guidelines in the domains of Air Traffic Management (ATM) and Healthcare (HC). A collaborative and iterative process has been defined involving relevant experts and practitioners. To ensure transnational, cross-sector applicability and uptake, a Community of Crisis and Resilience Practitioners (DARWIN DCoP) has been involved. The preliminary results indicate that a big step has been taken in moving from the resilience theory to practice. organization in the creation, assessment or improvement of its own reference guidelines, procedures and practices

    Environmental impact of omnivorous, ovo-lacto-vegetarian, and vegan diet

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    Food and beverage consumption has a great impact on the environment, although there is a lack of information concerning the whole diet. The environmental impact of 153 Italian adults (51 omnivores, 51 ovo-lacto-vegetarians, 51 vegans) and the inter-individual variability within dietary groups were assessed in a real-life context. Food intake was monitored with a 7-d dietary record to calculate nutritional values and environmental impacts (carbon, water, and ecological footprints). The Italian Mediterranean Index was used to evaluate the nutritional quality of each diet. The omnivorous choice generated worse carbon, water and ecological footprints than other diets. No differences were found for the environmental impacts of ovo-lacto-vegetarians and vegans, which also had diets more adherent to the Mediterranean pattern. A high inter-individual variability was observed through principal component analysis, showing that some vegetarians and vegans have higher environmental impacts than those of some omnivores. Thus, regardless of the environmental benefits of plant-based diets, there is a need for thinking in terms of individual dietary habits. To our knowledge, this is the first time environmental impacts of three dietary regimens are evaluated using individual recorded dietary intakes rather than hypothetical diet or diets averaged over a population
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