Long DNA palindromes pose a threat to genome stability. This instability is primarily mediated by slippage on the lagging strand of the replication fork between short directly repeated sequences close to the ends of the palindrome. The role of the palindrome is likely to be the juxtaposition of the directly repeated sequences by intrastrand base‐pairing. This intra‐strand base‐pairing, if present on both strands, results in a cruciform structure. In bacteria, cruciform structures have proved difficult to detect in vivo, suggesting that (...) if they form, they are either not replicated or are destroyed. SbcCD, a recently discovered exonuclease of Escherichia coli, is responsible for preventing the replication of long palindromes. These observations lead to the proposal that cells may have evolved a post‐replicative mechanism for the elimination and/or repair of large DNA secondary structures. (shrink)

A number of ways of taxonomizing human learning have been proposed. We examine the evidence for one such proposal, namely, that there exist independent explicit and implicit learning systems. This combines two further distinctions, (1) between learning that takes place with versus without concurrent awareness, and (2) between learning that involves the encoding of instances (or fragments) versus the induction of abstract rules or hypotheses. Implicit learning is assumed to involve unconscious rule learning. We examine the evidence for implicit learning (...) derived from subliminal learning, conditioning, artificial grammar learning, instrumental learning, and reaction times in sequence learning. We conclude that unconscious learning has not been satisfactorily established in any of these areas. The assumption that learning in some of these tasks (e.g., artificial grammar learning) is predominantly based on rule abstraction is questionable. When subjects cannot report the rules that govern stimulus selection, this is often because their knowledge consists of instances or fragments of the training stimuli rather than rules. In contrast to the distinction between conscious and unconscious learning, the distinction between instance and rule learning is a sound and meaningful way of taxonomizing human learning. We discuss various computational models of these two forms of learning. (shrink)

In the original target article (Shanks & St. John 1994), one of our principal conclusions was that there is almost no evidence that learning can occur outside awareness. The continuing commentaries raise some interesting questions, especially about the definition of learning, but do not lead us to abandon our conclusion.

Objectives—To evaluate a departmental computer system.Design—a. Direct comparison of the time taken to use a manual system with the time taken to use a computer system for lung function evaluation, loan of equipment and production of correspondence. b. Analysis of the accuracy of data capture before and after the introduction of the computer system. c. Analysis of the comparative running costs of the manual and computer systems.Setting—Within a department of respiratory medicine serving a hospital of 1323 beds.Main Outcome Measures—a. Time (...) taken to perform functions with the assistance of computerised methods, in comparison to the manual method used alone. b. Accuracy of data capture. c. Relative running costs.Results—a. The computer system was significantly faster than the manual system for lung function evaluation, loan of equipment, and checking for overdue equipment. The production of correspondence was slightly slower with the computer. b. All outpatient episodes, but only 43 of 65 of inpatient episodes, were captured. Lung function and managerial report data were accurate using both manual and computerised methods. The manual system for equipment loans was inefficient, and use of the computer resulted in the recovery of 221 nebulisers. c. Development costs for 1988–1990 were high. Only £1200 to £1845 per year was recovered directly from staff time saved by the computer but larger savings resulted from changes in work practice. After 10 years the projected deficit is £10 000 per annum in running costs.Conclusions—In comparison with the manual methods, the computer system has shown significant advantages which provide accurate information, with significant favourable effects on working practices. In evaluating computer systems used in clinical practice it is essential to ensure that the projected work practice benefits are achieved without unacceptable costs in staff time, inaccurate data and high financial outlay. (shrink)

Aim: Participation in classroom physical activity breaks may improve children’s cognition, but few studies have involved adolescents. The primary aim of this study was to examine the effects of classroom-based resistance training with and without cognitive training on adolescents’ cognitive function.Methods: Participants were 97 secondary school students. Four-year 10 classes from one school were included in this four-arm cluster randomized controlled trial. Classes were randomly assigned to the following groups: sedentary control with no cognitive training, sedentary with cognitive training, resistance (...) training without cognitive training, and resistance training with cognitive training. Sessions varied in levels of both cognitive demand and resistance training and were administered three times per week for 4 weeks. Inhibition, cognitive flexibility, episodic memory, on-task behavior, and muscular fitness were assessed at baseline and post-test. Linear mixed models were used to examine changes within and between groups.Results: In comparison with the control group, episodic memory improved significantly in the resistance training without cognitive training group. There were no group-by-time effects for inhibition or cognitive flexibility. Classroom activity breaks both with and without cognitive demand improved participants’ on-task behavior in comparison with the control and sedentary group. The resistance training programs did not lead to improvements in muscular fitness.Conclusion: Participation in body weight resistance training without cognitive training led to selective improvements in episodic memory. No training effects were found for inhibition or cognitive flexibility. A longer study period may be necessary to induce improvements in muscular fitness and associated changes in inhibition and cognitive flexibility.Clinical Trial Registration:https://www.anzctr.org.au/ACTRN12621001341819.aspx, Australian New Zealand Clinical Trials Registry—ACTRN12621001341819. (shrink)

Basson's introduction to Hume follows the pattern which has led to successful treatments of Aquinas and Kant in this series: he limits himself almost exclusively to exposition and minimal criticism, apparently assuming that the reader will not be able to obtain or to follow the original text.--R. F. T.

“Tell me," Wittgenstein once asked a friend, "why do people always say, it was natural for man to assume that the sun went round the earth rather than that the earth was rotating?" His friend replied, "Well, obviously because it just looks as though the Sun is going round the Earth." Wittgenstein replied, "Well, what would it have looked like if it had looked as though the Earth was rotating?” What would it have looked like if we looked at all (...) sciences from the viewpoint of Wittgenstein’s philosophy? Wittgenstein is undoubtedly one of the most influential philosophers of the twentieth century. His complex body of work has been analysed by numerous scholars, from mathematicians and physicists, to philosophers, linguists, and beyond. This volume brings together some of his central perspectives as applied to the modern sciences and studies the influence they may have on the thought processes underlying science and on the world view it engenders. The contributions stem from leading scholars in philosophy, mathematics, physics, economics, psychology and human sciences; all of them have written in an accessible style that demands little specialist knowledge, whilst clearly portraying and discussing the deep issues at hand. (shrink)

It has come to be expected that collections issued by the Royal Institute of Philosophy will contain work that has quality or is otherwise interesting. This volume runs true to form and presents plenty of both. It gives the proceedings of the conference arranged by the Institute at Exeter in 1973, consisting of five symposia together with Chairman's remarks of about eight pages or so for each symposium, and in three cases postscripts by the first speaker. The contributors and topics (...) are: R. F. Dearden and Elizabeth Telfer on ‘Autonomy as an Educational Ideal’ with R. M. Hare as Chairman; R. K. Elliott and Glenn Langford on ‘Education and the Development of the Understanding’ with Paul Hirst as Chairman; David Cooper and Timothy O'Hagan on ‘Quality and Equality in Education’ with R. F. Atkinson as Chairman; Mary Warnock and Richard Norman on ‘The Neutral Teacher’ with Alan Montefiore as Chairman; Stuart Brown and A. Phillips Griffiths on ‘Academic Freedom’ with R. S. Peters as Chairman. (shrink)

Chemosensory systems are complex regulatory pathways capable of perceiving external signals and translating them into different cellular behaviors such as motility and development. In the δ-proteobacterium Myxococcus xanthus, chemosensing allows groups of cells to orient themselves and aggregate into specialized multicellular biofilms termed fruiting bodies. M. xanthus contains eight predicted CSS and 21 chemoreceptors. In this work, we systematically deleted genes encoding components of each CSS and chemoreceptors and determined their effects on M. xanthus social behaviors. Then, to understand how (...) the 21 chemoreceptors are distributed among the eight CSS, we examined their phylogenetic distribution, genomic organization and subcellular localization. We found that, in vivo, receptors belonging to the same phylogenetic group colocalize and interact with CSS components of the respective phylogenetic group. Finally, we identified a large chemosensory module formed by three interconnected CSS and multiple chemoreceptors and showed that complex behaviors such as cell group motility and biofilm formation require regulatory apparatus composed of multiple interconnected Che-like systems. © 2014 Moine et al. (shrink)

This book taps the best American thinkers to answer the essential American question: How do we sustain our experiment in government of, by, and for the people? Authored by an extraordinary and politically diverse roster of public officials, scholars, and educators, these chapters describe our nation's civic education problem, assess its causes, offer an agenda for reform, and explain the high stakes at risk if we fail.

When there have been substantial failures by institutional leadership in their oversight responsibility to protect research integrity, the public should demand that these be recognized and addressed by the institution itself, or the funding bodies. This commentary discusses a case of research failures in developing genomic predictors for cancer risk assessment and treatment at a leading university. In its review of this case, the Office of Research Integrity, an agency within the US Department of Health and Human Services, focused their (...) report entirely on one individual faculty member and made no comment on the institution’s responsibility and its failure to provide adequate oversight and investigation. These actions missed an important opportunity to emphasize the institution’s critical responsibilities in oversight of research integrity and the importance of institutional transparency and accountability. (shrink)

: Catholic teaching has no moral difficulties with research on stem cells derived from adult stem cells or fetal cord blood. The ethical problem comes with embryonic stem cells since their genesis involves the destruction of a human embryo. However, there seems to be significant promise of health benefits from such research. Although Catholic teaching does not permit any destruction of human embryos, the question remains whether researchers in a Catholic institution, or any researchers opposed to destruction of human embryos, (...) could participate in research on cultured embryonic stem cells, or whether a Catholic institution could use any therapy that ultimately results from such research. This position paper examines how such research could be conducted legitimately in a Catholic institution by using an ethical analysis involving a narrative context, the nature of the moral act, and the principle of material cooperation, along with references to significant ethical assessments. It also offers tentative guidelines that could be used by a Catholic institution in implementing such research. (shrink)