91 research outputs found

    Developments in the Ni–Nb–Zr amorphous alloy membranes

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    Most of the global H2 production is derived from hydrocarbon-based fuels, and efficient H2/CO2 separation is necessary to deliver a high-purity H2 product. Hydrogen-selective alloy membranes are emerging as a viable alternative to traditional pressure swing adsorption processes as a means for H2/CO2 separation. These membranes can be formed from a wide range of alloys, and those based on Pd are the closest to commercial deployment. The high cost of Pd (USD *31,000 kg-1) is driving the development of less-expensive alternatives, including inexpensive amorphous (Ni60Nb40)100-xZrx alloys. Amorphous alloy membranes can be fabricated directly from the molten state into continuous ribbons via melt spinning and depending on the composition can exhibit relatively high hydrogen permeability between 473 and 673 K. Here we review recent developments in these low-cost membrane materials, especially with respect to permeation behavior, electrical transport properties, and understanding of local atomic order. To further understand the nature of these solids, atom probe tomography has been performed, revealing amorphous Nb-rich and Zr-rich clusters embedded in majority Ni matrix whose compositions deviated from the nominal overall composition of the membrane

    Arterial hypertension and cognitive deficit

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    Cognitive impairment and dementia are more and more common in the elderly. The first begins, it advances silently and it leads to dementia in few years. Arterial hypertension represents the most important cerebrovascular risk factor after age. In numerous studies an inverse relationship between blood pressure values and cognitive performance emerges: it is possible that arterial hypertension plays a role in the pathogenesis of cognitive decline. Even in asymptomatic subjects the magnetic resonance signs of cerebral damage accompany cognitive impairment development. Antihypertensive therapy influence on cognitive function represents a subject of actual interest. The most studied drugs are calcium antagonists and ACE-inhibitors; they seem to have a protective effect on cognitive impairment, with regard to diuretics and beta-blockers. It would be important to study hypertensive patients, above all young asymptomatic hypertensives, even about cognitive functions, to prevent and consider cognitive decline and effective organ damage

    Heaven can wait: How religion modulates temporal discounting.

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    Evidence suggests that religious systems have specific effects on attentional and action control processes. The present study investigated whether religions also modulate choices that involve higher-order knowledge and the delay of gratification in particular. We tested Dutch Calvinists, Italian Catholics, and Atheists from both countries/cultures using an intertemporal choice task where participants could choose between a small immediate and a larger delayed monetary reward. Based on the Calvinist theory of predestination and the Catholic concept of a cycle of sin-confession-expiation, we predicted a reduced delay tolerance, i.e. higher discount rate (DR), for Italian Catholics than for Dutch Calvinists, and intermediate rates for the two atheist groups. Analyses of discount rates support our hypotheses. We also found a magnitude effect on temporal discounting and faster responses for large than for small rewards across religions and countries/cultures. We conclude that temporal discounting is specifically modulated by religious upbringing rather than by generic cultural differences

    Heaven can wait: How religion modulates temporal discounting.

    No full text
    Evidence suggests that religious systems have specific effects on attentional and action control processes. The present study investigated whether religions also modulate choices that involve higher-order knowledge and the delay of gratification in particular. We tested Dutch Calvinists, Italian Catholics, and Atheists from both countries/cultures using an intertemporal choice task where participants could choose between a small immediate and a larger delayed monetary reward. Based on the Calvinist theory of predestination and the Catholic concept of a cycle of sin-confession-expiation, we predicted a reduced delay tolerance, i.e. higher discount rate (DR), for Italian Catholics than for Dutch Calvinists, and intermediate rates for the two atheist groups. Analyses of discount rates support our hypotheses. We also found a magnitude effect on temporal discounting and faster responses for large than for small rewards across religions and countries/cultures. We conclude that temporal discounting is specifically modulated by religious upbringing rather than by generic cultural differences
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