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Terhune DB  Brugger P 《PloS one》2011,6(12):e29206
Although forgetting is often regarded as a deficit that we need to control to optimize cognitive functioning, it can have beneficial effects in a number of contexts. We examined whether disrupting memory for previous numerical responses would attenuate repetition avoidance (the tendency to avoid repeating the same number) during random number generation and thereby improve the randomness of responses. Low suggestible and low dissociative and high dissociative highly suggestible individuals completed a random number generation task in a control condition, following a posthypnotic amnesia suggestion to forget previous numerical responses, and in a second control condition following the cancellation of the suggestion. High dissociative highly suggestible participants displayed a selective increase in repetitions during posthypnotic amnesia, with equivalent repetition frequency to a random system, whereas the other two groups exhibited repetition avoidance across conditions. Our results demonstrate that temporarily disrupting memory for previous numerical responses improves random number generation.  相似文献   

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Precise genome duplication requires accurate copying by DNA polymerases and the elimination of occasional mistakes by proofreading exonucleases and mismatch repair enzymes. The commonly held belief that 'if something is worth doing, then it's worth doing well' normally applies to DNA replication and repair, however, there are exceptions. This review describes elements that are crucial to cell fitness, evolution and survival in the recently discovered error-prone DNA polymerases. Large numbers of errant DNA polymerases, spanning microorganisms to humans, are used to rescue stalled replication forks by copying damaged DNA and even undamaged DNA to generate 'purposeful' mutations that generate genetic diversity in times of stress. Here we focus on low-fidelity polymerases from bacteria, comparing Escherichia coli, archeabacteria and those most recently discovered in Gram-positive Bacilli, Streptococcus, pathogenic Mycobacterium and intein-containing cyanobacteria.  相似文献   

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The present world population is largely fed by ‘industrialised agriculture’. This, in turn, depends on massive inputs of fossil fuels. While this energy expenditure is inescapable, it is an expensive way of ‘converting oil into potatoes'. Arguably, in view of global climate change, ever increasing population, ever increasing oil prices, ever diminishing availability of water and arable land, this is not sustainable. Despite the fact that biofuels inevitably compete for resources that might otherwise be used to grow, store and distribute food, they are frequently held to be desirable and feasible ‘green’ substitutes for fossil fuels and even that they spare carbon emissions to the atmosphere. This article challenges the absurdity of such ‘retro-agriculture’ (i.e. except in a few local circumstances) incurring yet more energy expenditure. It seeks to illustrate the misinformation on which some of the advocacy of biofuels has been based.  相似文献   

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Autophagy is a lysosomal degradation pathway that degrades damaged or superfluous cell components into basic biomolecules, which are then recycled back into the cytosol. In this respect, autophagy drives a flow of biomolecules in a continuous degradation-regeneration cycle. Autophagy is generally considered a pro-survival mechanism protecting cells under stress or poor nutrient conditions. Current research clearly shows that autophagy fulfills numerous functions in vital biological processes. It is implicated in development, differentiation, innate and adaptive immunity, ageing and cell death. In addition, accumulating evidence demonstrates interesting links between autophagy and several human diseases and tumor development. Therefore, autophagy seems to be an important player in the life and death of cells and organisms. Despite the mounting knowledge about autophagy, the mechanisms through which the autophagic machinery regulates these diverse processes are not entirely understood. In this review, we give a comprehensive overview of the autophagic signaling pathway, its role in general cellular processes and its connection to cell death. In addition, we present a brief overview of the possible contribution of defective autophagic signaling to disease.  相似文献   

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In non-Western and premodern societies, approaches to sickness involved moral considerations laden with existential and spiritual implications. Healers and physicians had access to this aspect of their patient's lives, were expected to use it constructively, and often did so. The contemporary biomedical theory of disease no longer assigns to illness such metaphysical connotations. While general physicians are permitted - perhaps even advised - to avoid involvement in morally laden dialogues tied to illness and the self, such dilemmas are more prominent and qualitatively different in psychiatry, as psychiatric conditions often entail changes in self-conception, psychological disaffection, unacceptable behavior, and untoward personal reactions to social circumstances. Manifestations of psychiatric conditions can overwhelm an individual's control in areas of cognition, emotion, autonomy, social responsibility, behavior, and body functions - exactly those matters that "modern" individualistic minds are supposed to master. Consequently, psychiatric conditions challenge basic presuppositions of the modern, secular credo about personhood, disease, and behavior. They comprise a species of human problems ontologically distinct from the conditions handled by other medical disciplines.  相似文献   

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Previous studies have concluded that thoroughbred racehorse speed is improving very slowly, if at all, despite heritable variation for performance and putatively intensive selective breeding. This has led to the suggestion that racehorses have reached a selection limit. However, previous studies have been limited, focusing only on the winning times of a few elite races run over middle and long distances, and failing to account for potentially confounding factors. Using a much larger dataset covering the full range of race distances and accounting for variation in factors such as ground softness, we show that improvement is, in fact, ongoing for the population as a whole, but driven largely by increasing speed in sprint races. In contrast, speed over middle and long distances, at least at the elite level, appears to be reaching an asymptote. Whether this reflects a selection limit to speed over middle and long distances or a shift in breeding practices to target sprint performances remains to be determined.  相似文献   

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Osteoporosis is a condition that is associated with an increased susceptibility for fractures. In the past few years, several drugs have become available that can reduce the incidence of fractures in patients with osteoporosis. Since these drugs work through different cellular mechanisms, combining agents of different classes may have an additive or multiplicative effect on fracture risk reduction. Combination treatments that have been evaluated in clinical trials include bisphosphonates with estrogen, raloxifene or PTH/ bisphosphonates and PTH/ estrogen. In general, these trials have shown increases in bone mineral density over that observed with each agent alone. However, whether anti-fracture efficacy is improved, or worsened remains to be established. This article reviews the combination treatments that have been evaluated in clinical trials, with a discussion of the potential benefits and risks that those treatments entail. Integrating safety and cost issues will eventually determine whether those combinations will become the standard of care.  相似文献   

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