Quantum theory is one of science's most thrilling, challenging and even mysterious areas. Scientists such as Planck, Einstein, Bohr, Heisenberg and Schrödinger uncovered bizarre paradoxes in the early 20th century that seemed to destroy the fundamental assumptions of 'classical physics' - the basic laws we are taught in school. Notoriously difficult, quantum theory is nonetheless an amazing and inspiring intellectual adventure, explained here with patience, wit and clarity.

Three experiments explore the role of working memory in motor skill acquisition and performance. Traditional theories postulate that skill acquisition proceeds through stages of knowing, which are initially declarative but later procedural. The reported experiments challenge that view and support an independent, parallel processing model, which predicts that procedural and declarative knowledge can be acquired separately and that the former does not depend on the availability of working memory, whereas, the latter does. The behaviour of these two processes was manipulated (...) by providing or withholding visual (and auditory) appraisal of outcome feedback. Withholding feedback was predicted to inhibit the use of working memory to appraise success and, thus, prevent the formation of declarative knowledge without affecting the accumulation of procedural knowledge. While the first experiment failed to support these predictions, the second and third experiments demonstrated that procedural and declarative knowledge can be acquired independently. It is suggested that the availability of working memory is crucial to motor performance only when the learner has come to rely on its use. (shrink)

_Naturalism_ provides a rigorous analysis and critique of the major varieties of contemporary philosophical naturalism. The authors advocate the thesis that contemporary naturalism should be abandoned, in light of the serious objections raised against it. Contributors draw on a wide range of topics including: epistemology, the philosophy of science, the philosophy of mind and agency, and natural theology.

In a recent discussion, Earman and Norton [(1998)] propose a classification of supertasks that generate indeterminism which is flawed. An emendation is presented here.

We discuss quantum electrodynamics within the framework of a new four-dimensional symmetry in which the concept of time, the propagation of light, and the transformation property of many physical quantities are drastically different from those in special relativity. However, they are consistent with experiments. The new framework allows for natural developments of additional concepts. Observers in different frames may use the same grid of clocks, located in any one of the frames, and hence have a universal time.

The paper shows a new example of nonuniqueness of the solutionto Newtonian equations of motion for infinite gravitational systems. Unlike otherexamples, the gravitational field presents no singularity, nor are the non-gravitational forcesintroduced in the model singular (in particular, there are no collisions). The result is also ofinterest because it points to an interesting limitation of the elementary (Newtonian) formulationof classical mechanics.

Following the ideas of Poincaré, Reichenbach, and Grunbaum concerning the convention of setting up clock systems, we analyze clock systems and light propagation within the framework of four-dimensional symmetry. It is possible to construct a new four-dimensional symmetry framework incorporatingcommon time: observers in different inertial frames of reference use one and the same clock system, which is located in any one of the frames. Consequently, simultaneity has a meaning independent of position and independent of frame of reference. A further consequence (...) is that the two-way speeds of light alone are isotropic in any frame. By the choice of clock system there will be one frame in which the one-way speed of light is isotropic. This frame can be arbitrarily chosen. The difference between one-way speeds and two-way speeds of light signals is considered in detail. (shrink)

The Michelson-Morley result is described empirically by generalized Doppler equations. If the phase of a light wave is not invariant, in agreement with the quantum nature of light, special-relativistic kinematics need not be assumed. Einstein particle dynamics and Maxwell-Lorentz electrodynamics in a moving system are derived without assuming special-relativistic kinematics. An alternative explanation for the decay rate of moving radioactive particles is presented. The observation of a third-order Doppler effect may yield the velocity of the closed laboratory.

This article describes new aspects of hysteresis dynamics which have been uncovered through computer experiments. There are several motivations to be interested in fast-slow dynamics. For instance, many physiological or biological systems display different time scales. The bursting oscillations which can be observed in neurons, β-cells of the pancreas and population dynamics are essentially studied via bifurcation theory and analysis of fast-slow systems (Keener and Sneyd, 1998; Rinzel, 1987). Hysteresis is a possible mechanism to generate bursting oscillations. A first part (...) of this article presents the computer techniques (the dotted-phase portrait, the bifurcation of the fast dynamics and the wave form) we have used to represent several patterns specific to hysteresis dynamics. This framework yields a natural generalization to the notion of bursting oscillations where, for instance, the active phase is chaotic and alternates with a quiescent phase. In a second part of the article, we emphasize the evolution to chaos which is often associated with bursting oscillations on the specific example of the Hindmarsh–Rose system. This evolution to chaos has already been studied with classical tools of dynamical systems but we give here numerical evidence on hysteresis dynamics and on some aspects of the wave form. The analytical proofs will be given elsewhere. (shrink)

Thus reads the ‘optimus Laurentianus,’ and starting hence we shall refuse claudent, the facile but incoherent correction of some MSS., and still more the claudunt which the majority offer. Nor for all that shall we make the ineptitude of these readings a ground for condemning the pentameter, which, save for its lack of grammatical construction, is perfectly faultless in expression. Turning our attention to the hexameter, we observe that Parca, a synonym for fata with trahebat will set everything right. The (...) offending fata is due to a gloss or an unfortunate reminiscence. (shrink)

Among the multitude of commentators by which an Horatian crux is surrounded it is reasonable to suppose that one or two at least have seen some vestiges of the truth, and I will therefore preface my remarks upon the meaning of this ode and its ultimate stanza by quoting first from an annotation by Dean Wickham.

There are two undoubted instances of this use of Neaera in Prudentius which are cited by Mr. Ullman in support of his contention that in Horace another proper name may be similarly employed. I imagine however that to an unprejudiced sense of Latin usage these instances will themselves seem to be strange and in need of explanation.

The following notes are based on the apparatus criticus in the edition of E. T. Merrill : I. 20. 5 ‘uides ut statuas, signa, picturas, hominum denique multorumqne animalium formas, arborum etiam, si modo sint decorae, nihil magis quam amplitudo commendet.’ Why ‘many animals’ and not ‘many men’ and ‘many trees’? Read mutorum; with ‘animalia,’ a standing opposition to ‘homines,’ as in Seneca, Ep. 76. 26 'ea quae tam homini contingunt quam mutis animalibus, 'where also it has been corrupted to (...) multis as in many other places. (shrink)

Mr. Garrod has earned the gratitude of all students of Manilius by his detection of the ratio of the series in iii. 599–615, and he is fully justified in his contention that tricenas in 612 is ‘one of the few emendations which can be proved mathematically.’ I owe him a special acknowledgment, inasmuch as his discovery enables me to add one more to the list and affords me an opportunity of establishing what was correct and correcting what was erroneous in (...) my discussion of the whole passage in Silua Maniliana, pp. 30 sqq. Let me do the last first. My suggestion of uix for bis in 616 of course disappears; bis sex is required by the series: and in 595–6 the number meant is 75, not 76. (shrink)

Dissatisfied with current views upon the exordium of Tibullus II. i., I proposed in Selections from Tibullus to make the occasion of the poem the Sementiuae Feriae instead of the Ambarualia. This proposal, criticised, amongst others, by Mr. Warde Fowler in an interesting article in the Classical Review, I have now abandoned. But the difficulties which led me to break away from previous exegesis still remain, and to them I address myself in the present article.