23 research outputs found

    Working memory capacity is related to variations in the magnitude of an electrophysiological marker of recollection

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    he links between the resources available for cognitive control and the ability to recover and maintain episodic content were investigated by contrasting an ERP index of recollection (the left-parietal ERP old/new effect) with a measure of working memory capacity (WMC). Participants were given the O-Span measure of WMC and completed a retrieval task in which they had to make responses on one key to previously studied words (targets) and responses on a second key to words that were presented at retrieval on either one or two occasions (new words and non-targets, respectively). The size of the ERP index of recollection associated with correct responses to targets was correlated with WMC, a finding consistent with the view that this ERP effect is linked to operations associated with maintaining information on-line in service of task goals. In addition, the degree to which left-parietal ERP old/new effects for targets were larger than for non-targets increased as WMC increased. Larger left-parietal ERP old/new effects for targets than for non-targets have been interpreted as evidence of successful prioritisation of recollection of target information. The link with WMC reported here is consistent this view, in so far as WMC indexes the availability of resources that are necessary to exert cognitive control over memory retrieval

    Critical end point behaviour in a binary fluid mixture

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    We consider the liquid-gas phase boundary in a binary fluid mixture near its critical end point. Using general scaling arguments we show that the diameter of the liquid-gas coexistence curve exhibits singular behaviour as the critical end point is approached. This prediction is tested by means of extensive Monte-Carlo simulations of a symmetrical Lennard-Jones binary mixture within the grand canonical ensemble. The simulation results show clear evidence for the proposed singularity, as well as confirming a previously predicted singularity in the coexistence chemical potential [Fisher and Upton, Phys. Rev. Lett. 65, 2402 (1990)]. The results suggest that the observed singularities, particularly that in the coexistence diameter, should also be detectable experimentally.Comment: 17 pages Revtex, 11 epsf figures. To appear in Phys. Rev.

    Whole-genome sequencing reveals host factors underlying critical COVID-19

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    Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

    The role of working memory capacity in the control of recollection

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    The links between control over recollection and working memory capacity (WMC) were investigated using event-related potentials (ERPs) and behavioural assays. Electrophysiological evidence for a relationship between greater control over recollection and higher scores on a measure of WMC was obtained. In addition, people with high WMC who first completed a task requiring cognitive control showed no electrophysiological evidence for control over recollection on a subsequent task. This outcome suggests a causal link between control over recollection and the availability of WMC, in so far as the consequence of completing the first task was a reduction in WMC that impacted on completion of the subsequent task. All participants also completed a final recall task, on which they were asked to remember the stimuli they had encountered during the task in which ERPs were acquired. Only those participants who showed electrophysiological evidence for the exertion of control over recollection showed differences between the likelihoods of recalling stimuli over which control either had or had not been exerted. In combination, the findings provide insights into the conditions under which control over recollection occurs, and make a strong argument for including individual difference measures of resource availability when assessing how and when people exert control over what they remember. © 2012 Elsevier Ltd

    An audio-based personal memory aid

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    We are developing a wearable device that attempts to alleviate some everyday memory problems. The “memory prosthesis” records audio and contextual information from conversations and provides a suite of retrieval tools (on both the wearable and a personal computer) to help users access forgotten memories in a timely fashion. This paper describes the wearable device, the personal-computer-based retrieval tool, and their supporting technologies. Anecdotal observations based on real-world use and quantitative results based on a controlled memory-retrieval task are reported. Finally, some social, legal, and design challenges of ubiquitous recording and remembering via a personal audio archive are discussed

    Acidification of soils by trees and forests.

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    The impact of isolated trees and natural forest vegetation on soil acidity is discussed. There is a considerable variation in impact between species on similar soils and between sites for any given species. The effect of coniferous plantations on soil acidity is reviewed and the causes of any increased acidity discussed. Crop species, initial soil conditions, silvicultural practices and the proportion of the tree removed at felling are all important factors influencing the long-term impact of plantations on soil acidity
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