23 research outputs found
Spontaneous and deliberate future thinking: A dual process account
© 2019 Springer Nature.This is the final published version of an article published in Psychological Research, licensed under a Creative Commons Attri-bution 4.0 International License. Available online at: https://doi.org/10.1007/s00426-019-01262-7.In this article, we address an apparent paradox in the literature on mental time travel and mind-wandering: How is it possible that future thinking is both constructive, yet often experienced as occurring spontaneously? We identify and describe two ‘routes’ whereby episodic future thoughts are brought to consciousness, with each of the ‘routes’ being associated with separable cognitive processes and functions. Voluntary future thinking relies on controlled, deliberate and slow cognitive processing. The other, termed involuntary or spontaneous future thinking, relies on automatic processes that allows ‘fully-fledged’ episodic future thoughts to freely come to mind, often triggered by internal or external cues. To unravel the paradox, we propose that the majority of spontaneous future thoughts are ‘pre-made’ (i.e., each spontaneous future thought is a re-iteration of a previously constructed future event), and therefore based on simple, well-understood, memory processes. We also propose that the pre-made hypothesis explains why spontaneous future thoughts occur rapidly, are similar to involuntary memories, and predominantly about upcoming tasks and goals. We also raise the possibility that spontaneous future thinking is the default mode of imagining the future. This dual process approach complements and extends standard theoretical approaches that emphasise constructive simulation, and outlines novel opportunities for researchers examining voluntary and spontaneous forms of future thinking.Peer reviewe
Influence of modern coal-fired power technologies on fly ash properties and its use in concrete
The work reported in this paper investigated the properties and use of fly ash (FA) produced from technologies developed to reduce the environmental impact and improve the efficiency of the coal-fired power generation process. These include nitrogen oxides (NO x) reduction, co-combustion, supercritical steam technology and oxy-fuel combustion. The nine FA samples examined from these technologies were characterised physically, chemically and in terms of their reactivity. Tests were also carried out to determine the consistence (slump) and compressive strength of FA concretes. Comparisons were made with a selection of reference FAs, the requirements of BS EN 450-1 and reported FA studies from the 1980s and 1990s. The results indicated that, for some technologies, the FA tended to be coarser and of higher loss on ignition (co-combustion and in-combustion NO x reduction) while, for others lower carbon contents were found (supercritical steam) or there was little obvious effect. FA chemistry was slightly affected in some cases, but mainly as expected for the coal being used. There was general agreement between water requirement and activity index with FA fineness for the materials tested. For the FA concretes, similar effects were noted in terms of the dosage of superplasticising admixture needed for a target slump and compressive strength. The behaviour of the materials from the new technologies was found to be similar to that reported in earlier studies on FA and suggests suitability for their use in concrete construction. </p
Neuroprotection by adenosine in the brain: From A1 receptor activation to A2A receptor blockade
Adenosine is a neuromodulator that operates via the most abundant inhibitory adenosine A1 receptors (A1Rs) and the less abundant, but widespread, facilitatory A2ARs. It is commonly assumed that A1Rs play a key role in neuroprotection since they decrease glutamate release and hyperpolarize neurons. In fact, A1R activation at the onset of neuronal injury attenuates brain damage, whereas its blockade exacerbates damage in adult animals. However, there is a down-regulation of central A1Rs in chronic noxious situations. In contrast, A2ARs are up-regulated in noxious brain conditions and their blockade confers robust brain neuroprotection in adult animals. The brain neuroprotective effect of A2AR antagonists is maintained in chronic noxious brain conditions without observable peripheral effects, thus justifying the interest of A2AR antagonists as novel protective agents in neurodegenerative diseases such as Parkinson’s and Alzheimer’s disease, ischemic brain damage and epilepsy. The greater interest of A2AR blockade compared to A1R activation does not mean that A1R activation is irrelevant for a neuroprotective strategy. In fact, it is proposed that coupling A2AR antagonists with strategies aimed at bursting the levels of extracellular adenosine (by inhibiting adenosine kinase) to activate A1Rs might constitute the more robust brain neuroprotective strategy based on the adenosine neuromodulatory system. This strategy should be useful in adult animals and especially in the elderly (where brain pathologies are prevalent) but is not valid for fetus or newborns where the impact of adenosine receptors on brain damage is different
