259 research outputs found

    Extensibility and rheology of collenchyma I. Creep relaxation and viscoelasticity of young and senescent cells

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    The extensibility of collenchyma cells was methodologically analyzed; extensibility (elasticity and plasticity) and rheology of this tissue are discussed. Experimental conditions are described. Rheological data for young and senescent cells were obtained; they were found to be not Boltzmannian. The permanent strain is not viscous, and is larger for young cells than older one

    Extensibility and rheology of collenchyma cells: II. Low-pH effect on the extension of collocytes isolated from high- and low-growing material

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    Low-pH effects were studied on the extension of isolated fresh, methanol-killed and frozen-thawed collocytes. Fresh and frozen-thawed samples responded to low pH. This response decreased with increasing differentiation. A yield stress was found for frozen-thawed samples. The significance of the response during growth and differentiation is discusse

    Conceptualizing human resilience in the face of the global epidemiology of cyber attacks

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    Computer security is a complex global phenomenon where different populations interact, and the infection of one person creates risk for another. Given the dynamics and scope of cyber campaigns, studies of local resilience without reference to global populations are inadequate. In this paper we describe a set of minimal requirements for implementing a global epidemiological infrastructure to understand and respond to large-scale computer security outbreaks. We enumerate the relevant dimensions, the applicable measurement tools, and define a systematic approach to evaluate cyber security resilience. From the experience in conceptualizing and designing a cross-national coordinated phishing resilience evaluation we describe the cultural, logistic, and regulatory challenges to this proposed public health approach to global computer assault resilience. We conclude that mechanisms for systematic evaluations of global attacks and the resilience against those attacks exist. Coordinated global science is needed to address organised global ecrime

    International comparison of health care carbon footprints

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    Climate change confronts the health care sector with a dual challenge. Accumulating climate impacts are putting an increased burden on the service provision of already stressed health care systems in many regions of the world. At the same time, the Paris agreement requires rapid emission reductions in all sectors of the global economy to stay well below the 2 °C target. This study shows that in OECD countries, China, and India, health care on average accounts for 5% of the national CO2 footprint making the sector comparable in importance to the food sector. Some countries have seen reduced CO2 emissions related to health care despite growing expenditures since 2000, mirroring their economy wide emission trends. The average per capita health carbon footprint across the country sample in 2014 was 0.6 tCO2, varying between 1.51 tCO2/cap in the US and 0.06 tCO2/cap in India. A statistical analysis shows that the carbon intensity of the domestic energy system, the energy intensity of the domestic economy, and health care expenditure together explain half of the variance in per capita health carbon footprints. Our results indicate that important leverage points exist inside and outside the health sector. We discuss our findings in the context of the existing literature on the potentials and challenges of reducing GHG emissions in the health and energy sector.Austrian Climate Research ProgramPeer Reviewe

    Pressure Induced Change in the Magnetic Modulation of CeRhIn5

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    We report the results of a high pressure neutron diffraction study of the heavy fermion compound CeRhIn5 down to 1.8 K. CeRhIn5 is known to order magnetically below 3.8 K with an incommensurate structure. The application of hydrostatic pressure up to 8.6 kbar produces no change in the magnetic wave vector qm. At 10 kbar of pressure however, a sudden change in the magnetic structure occurs. Although the magnetic transition temperature remains the same, qm increases from (0.5, 0.5, 0.298) to (0.5, 0.5, 0.396). This change in the magnetic modulation may be the outcome of a change in the electronic character of this material at 10 kbar.Comment: 4 pages, 3 figures include
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