Multiple universes, cosmic coincidences, and other dark matters

Even when completely and consistently formulated, a fundamental theory of physics and cosmological boundary conditions may not give unambiguous and unique predictions for the universe we observe; indeed inflation, string/M theory, and quantum cosmology all arguably suggest that we can observe only one member of an ensemble with diverse properties. How, then, can such theories be tested? It has been variously asserted that in a future measurement we should observe the a priori most probable set of predicted properties (the ``bottom-up'' approach), or the most probable set compatible with all current observations (the ``top-down'' approach), or the most probable set consistent with the existence of observers (the ``anthropic'' approach). These inhabit a spectrum of levels of conditionalization and can lead to qualitatively different predictions. For example, in a context in which the densities of various species of dark matter vary among members of an ensemble of otherwise similar regions, from the top-down or anthropic viewpoints -- but not the bottom-up -- it would be natural for us to observe multiple types of dark matter with similar contributions to the observed dark matter density. In the anthropic approach it is also possible in principle to strengthen this argument and the limit the number of likely dark matter sub-components. In both cases the argument may be extendible to dark energy or primordial density perturbations. This implies that the anthropic approach to cosmology, introduced in part to explain "coincidences" between unrelated constituents of our universe, predicts that more, as-yet-unobserved coincidences should come to light.Comment: 18 JCAP-style pages, accepted by JCAP. Revised version adds references and some clarification

Between the Post and the Com-Post:Examining the Postdigital ‘Work’ of a Prefix

In examining the work of the prefix ‘post’, we aim to contribute to the current postdigital dialogue. Our paper does not provide a rationale for the use of ‘postdigital’ in the title of this journal: that has been thoroughly explored elsewhere. We want instead to consider the work the prefix might do. We look at ‘post’, as it appears to ‘act’ in the terms of ‘postmodernism’ and ‘posthumanism’, suggesting that modernism and humanism are in need of questioning and reworking. We also examine what gets ‘post-ed’, or sometimes ‘com-posted’. (Com- is another interesting prefix, meaning ‘with’.) We then consider how these inquiries inform our understanding of a ‘postdigital reality’ that humans now inhabit. We understand this as a space of learning, struggle, and hope, where ‘old’ and ‘new’ media are now ‘cohabiting artefacts’ that enmesh with the economy, politics and culture. In entering this postdigital age, there really is no turning back from a convergence of the traditional and the digital. However, this is not simply a debate about technological and non-technological media. The postdigital throws up new challenges and possibilities across all aspects of social life. We believe this opens up new avenues too, for considering ways that discourse (language-in-use) shapes how we experience the postdigital

The Presence of Infectious Virus but not Conventional Antigen can Exacerbate Graft-Versus-Host Reactions

Previous reports have demonstrated that the introduction of virus (MCMV, HSV-1) concurrent with a graft-versus-host reaction (GvHR) limited to a class I MHC disparity can result in the enhancement of GvHR-associated phenotypic (changes in CD4/CD8 ratio) and functional (inability to produce secondary antibody responses) alterations including the augmentation of in situ natural killer (NK) and donor anti-host cytotoxic T-cell activity. In the present study, we investigated whether immunogens other than infectious virus may be capable of enhancing GvHR. Mice receiving donor cells and the T-dependent antigen dinitrophenyl-bovine serum albumin (DNP-BSA) did not display exacerbated GvHR as evidenced by the absence of phenotypic alterations and the absence of elevated NK activity and the lack of donor anti-host cytotoxic activity. Furthermore, these recipients produced normal levels of IgM and IgG anti-DNP antibody. In addition, mice which received ultraviolet light (UV)-inactivated virus (even at 100 x dosage) together with donor cells also did not exhibit exacerbated GvHR. In total, these findings illustrate a novel ability of infectious virus to exacerbate GvH reactions and are consistent with the hypothesis that viral-induced immune responses may be important in the ability of a pathogen to induce the development of severe GvHR

Developing immunity to flight security risk: prospective benefits from considering aviation security as a socio-technical eco-system

Since 9/11, preventing similar terrorist disasters has been the predominant goal of aviation security. Yet, in this paper we seek to explore why it is that despite our increased knowledge of disaster causation - aviation security systems still remain vulnerable to future exploitation by adaptive terrorists and other threat groups. We adopt a novel approach, and present early directions of how we apply the benefits of high level appreciations of socio-technical and biological eco-systems to existing complex aviation transportation security systems. We propose that by approaching aviation security as a complex socio-technical eco-system, it offers an opportunity to think beyond conventional methodologies to improve system performance in a way that, hitherto, would not have been possible. The paper concerns itself with the ability for aviation socio-technical eco-systems to hold the capacity to proactively identify and mitigate pathogenic errors and violations. This narrow view is juxtaposed with identifying methods of reducing error creation ‘before’ they become system vulnerabilities. To address this problem, the paper concludes that a fresh approach, both conceptually and operationally, is required to understand that ‘true’ foresight of latent vulnerabilities can only be achieved by a system which is ‘intelligent’ and ‘self-aware’, in other words to identify and modify hostile pathogens before they are exploited. The development of true foresight in aviation security systems is critical to the prevention of future terrorist attacks