This paper charts P.A.M. Dirac’s development of his theory of the electron, and its radical picture of empty space as an almost-full plenum. Dirac’s Quantum Electrodynamics famously accomplished more than the unification of special relativity and quantum mechanics. It also accounted for the ‘duplexity phenomena’ of spectral line splitting that we now attribute to electron spin. But the extra mathematical terms that allowed for spin were not alone, and this paper charts Dirac’s struggle to ignore or account (...) for them as a sea of strange, negative-energy, particles with positive ‘holes’. This work was not done in solitude, but rather in exchanges with Dirac’s correspondence network. This social context for Dirac’s work contests his image as a lone genius, and documents a community wrestling with the ontological consequences of their work. Unification, consistency, causality, and community are common factors in explanations in the history of physics. This paper argues on the basis of materials in Dirac’s archive that — in addition — mathematical beauty was an epistemological factor in the development of the electron and hole theory. In fact, if we believe that Dirac’s beautiful mathematics captures something of the world, then there is both an epistemology and an ontology of mathematical beauty. (shrink)

Integrated information theory (IIT) is a candidate theory of consciousness that highlights the role of complex interactions between parts of a system as the basis of consciousness – and, due to its general information-theoretic formulation, is capable of making statements about consciousness in neural and non-neural systems alike. Here, we argue that a system radically different to a human brain, host to complex physiological and functional structures capable of integrating information, can be found in the meristems and vascular system of (...) higher plants. Following a pragmatic and ontologically innocent approach, neither taking for granted that plants are conscious nor dismissing the possibility that they are, we argue that the time is ripe to apply analysis tools inspired by IIT to plants, taking advantage of recent developments in both plant imaging and information theory. We introduce and discuss the relevant literature, and pro information and integration in plant behaviour, assessing the plausibility of plant sentience. If successful, these experiments could position plants as the next frontier in consciousness science, and urge us to rethink our perspectives on consciousness, how to measure it, and its prevalence amongst living beings. (shrink)

Acontius argues that there was nothing wrong with the trick he played on Cydippe – the end justifies the means.Heinsius and Dilthey doubted the authenticity of this couplet, whilst Bornecque bracketed line 26 alone. Line 25, however, contains a familiar elegiac theme, and line 26, with one small emendation, is rhetorically sharp.All the MSS have uni in line 25, but many editors have found this unsatisfactory, preferring to read unum and punctuating the line in various ways: Burman prints ‘iungerer? unum’, (...) Showerman, Goold and Palmer ‘iungerer, unum?’ Of these, the latter is the more attractive, ‘iungerer uni’, however, is perfectly good, and should be retained: uni means not ‘you alone ’, but ‘you alone ’, cf. OLD s.v. unus 8 ‘one in particular, one above all others’. Acontius is paying Cydippe a compliment – she is the only girl for him, and nobody else will do. This is a common theme in Latin love elegy, cf. Prop. 2.7.19, [Tib.] 3.19.3–6, Ovid, Ars Am. 1.42: ‘elige cui dicas “tu mihi sola places”’. (shrink)

It is usually supposed that the Dirac and radiation equations predict that the phase of a fermion will rotate through half the angle through which the fermion is rotated, which means, via the measured dynamical and geometrical phase factors, that the fermion must have a half-integral spin. We demonstrate that this is not the case and that the identical relativistic quantum mechanics can also be derived with the phase of the fermion rotating through the same angle as does the (...) fermion itself. Under spatial rotation and Lorentz transformation the bispinor transforms as a four-vector like the potential and Dirac current. Previous attempts to provide this form of transformational behavior have foundered because a satisfactory current could not be derived.(14). (shrink)

Acontius argues that there was nothing wrong with the trick he played on Cydippe – the end justifies the means.Heinsius and Dilthey doubted the authenticity of this couplet, whilst Bornecque bracketed line 26 alone. Line 25, however, contains a familiar elegiac theme, and line 26, with one small emendation, is rhetorically sharp.All the MSS have uni in line 25, but many editors have found this unsatisfactory, preferring to read unum and punctuating the line in various ways: Burman prints ‘iungerer? unum’, (...) Showerman, Goold and Palmer ‘iungerer, unum?’ Of these, the latter is the more attractive, ‘iungerer uni’, however, is perfectly good, and should be retained: uni means not ‘you alone ’, but ‘you alone ’, cf. OLD s.v. unus 8 ‘one in particular, one above all others’. Acontius is paying Cydippe a compliment – she is the only girl for him, and nobody else will do. This is a common theme in Latin love elegy, cf. Prop. 2.7.19, [Tib.] 3.19.3–6, Ovid, Ars Am. 1.42: ‘elige cui dicas “tu mihi sola places”’. (shrink)

We complete our previous(1, 2) demonstration that there is a family of new solutions to the photon and Dirac equations using spatial and temporal circles and four-vector behaviour of the Dirac bispinor. We analyse one solution for a bound state, which is equivalent to the attractive two-body interaction between a charged point particle and a second, which remains at rest. We show this yields energy and angular momentum eigenvalues that are identical to those found by the usual method (...) of solving of the Dirac equation,(4) including fine structure. We complete our previous derivation(2) of QED from a set of rules for the two-body interaction and generalise these. We show that QED may be decomposed into a two-body interaction at every point in spacetime. (shrink)

We have shown in a previous paper that the Dirac bispinor can vary like a four-vector and that Quantum Electrodynamics can be reproduced with this form of behaviour. In Part I of this paper, we show that QED with the same transformational behaviour also holds in an alternative space we call M-space. We use the four-vector behaviour to model the two-body interaction in M and show that this has similar physical properties to the usual model in L which it (...) predicts. In Part II of this paper we use M-space to show that QED can be reduced to two simple rules for a two-body interaction. (shrink)

Objectives To investigate empirically the motivations for not consenting to DNA biobanking in a Swedish population-based study and to discuss the implications. Design Structured questionnaires and semistructured interviews. Setting A longitudinal epidemiological project (PART) ongoing since 1998 in Stockholm, Sweden. The DNA-collection wave took place during 2006–7. Participants 903 individuals completed the questionnaire (participation rate 36%) and 23 were interviewed. All individuals had participated in both non-genetic waves of the project, but refused to contribute saliva samples during the DNA-collection wave. (...) Main outcome measures Motivations behind refusing to consent to DNA biobanking, with subsequent focus on participants' explanations regarding this unwillingness. Results Public refusal to consent to DNA biobanking, as revealed by the questionnaire, was mainly explained by a lack of personal relevance of DNA contribution and feelings of discomfort related to the DNA being used for purposes other than the respective study. Interviews of individuals representing the second motivation, revealed a significant mistrust of DNA biobank studies. The underlying beliefs and attitudes were associated with concerns about integrity, privacy, suspiciousness and insecurity. However, most interviewees were supportive of genetic research per se and interpreted their mistrust in the light of distressing environmental influences. Conclusion The results suggest a need for guidelines on benefit sharing, as well as trustworthy and stable measures to maintain privacy, as a means for increasing personal relevance and trust among potential participants in genetic research. Measures taken from biobanks seem insufficient in maintaining and increasing trust, suggesting that broader societal measures should be taken. (shrink)

A relative value of life dependent on age has been produced from a survey of 721 randomly selected individuals together with other observations of professional practice. The results are presented in diagrammatic form. If two identical people, except for age, present for medical treatment for a life-threatening condition and only one can be treated then the diagram indicates what the choice should be.

In its original form Dirac's equations have been expressed by use of the γ-matrices γμ, μ=0, 1, 2, 3. They are elements of the matrix algebra M 4 (ℂ). As emphasized by Hestenes several times, the γ-matrices are merely a (faithful) matrix representation of an orthonormal basis of the orthogonal spaceℝ 1,3, generating the real Clifford algebra Cl 1,3 . This orthonormal basis is also denoted by γμ, μ=0, 1, 2, 3. The use of the matrix algebra M 4 (...) (ℂ) to represent Cl 1,3 has some unsatisfactory aspects. The γ-matrices contain imaginary numbers as entries whereas Cl 1,3 is real. Moreover, as a matrix algebra Cl 1,3 is M 2 (ℍ) but only a part of M 4 (ℂ). For that reason we investigate in this paper several forms of Dirac's equations in terms of M 2 (ℍ) instead of M 4 (ℂ). In Section1 we survey Dirac's equations describing the interaction of matter with electromagnetic, electroweak, and strong fields. Section2 deals with electromagnetic/weak interactions employing M 2 (ℍ). Finally, in Section3 we deal with Dirac's equations for strong interactions between quarks. In contrast to su(2) ⊕ u(1), the Lie algebra su(3) is not isomorphic to any subalgebra of Cl 1,3 . Therefore we do not give a description of strong interactions by use of M 2 (ℍ). Instead of such an approach we describe these interactions using the space of quadruples of bivector fields in Cl 1,3 . The thus obtained description has remarkable formal resemblance to the original Dirac equations using wave functions with values in the linear spaceℂ 4. (shrink)

We characterize strict Mittag-Leffler modules in terms of free realizations of positive primitive formulas, and rings over which projectives are trivial in terms of various notions of separability of strict Mittag-Leffler modules. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The four-year wrangle over the ownership of what was then thought to have been the largest known meteorite, recognized near Melbourne in 1860, provides a fine-grained example of the interaction between scientific internationalism, metropolitan appetite for specimens, and colonial civic pride.

The dominant position in Philosophy of Science contends that downward causation is an illusion. Instead, we argue that downward causation doesn’t introduce vicious circles either in physics or in biology. We also question the metaphysical claim that “physical facts fix all the facts.” Downward causation does not imply any contradiction if we reject the assumption of the completeness and the causal closure of the physical world that this assertion contains. We provide an argument for rejecting this assumption. Furthermore, this allows (...) us to reconsider the concept of diachronic emergence. (shrink)