90 research outputs found
No multi-graviton theories in the presence of a Dirac field
The cross-couplings among several massless spin-two fields (described in the
free limit by a sum of Pauli-Fierz actions) in the presence of a Dirac field
are investigated in the framework of the deformation theory based on local BRST
cohomology. Under the hypotheses of locality, smoothness of the interactions in
the coupling constant, Poincare invariance, (background) Lorentz invariance and
the preservation of the number of derivatives on each field, we prove that
there are no consistent cross-interactions among different gravitons in the
presence of a Dirac field. The basic features of the couplings between a single
Pauli-Fierz field and a Dirac field are also emphasized.Comment: 48 page
Gauged Gravity via Spectral Asymptotics of non-Laplace type Operators
We construct invariant differential operators acting on sections of vector
bundles of densities over a smooth manifold without using a Riemannian metric.
The spectral invariants of such operators are invariant under both the
diffeomorphisms and the gauge transformations and can be used to induce a new
theory of gravitation. It can be viewed as a matrix generalization of Einstein
general relativity that reproduces the standard Einstein theory in the weak
deformation limit. Relations with various mathematical constructions such as
Finsler geometry and Hodge-de Rham theory are discussed.Comment: Version accepted by J. High Energy Phys. Introduction and Discussion
significantly expanded. References added and updated. (41 pages, LaTeX: JHEP3
class, no figures
Health as a Driving Economic Force
This chapter illustrates the contribution which could be made to realising the Lisbon Strategy of the European Union for growth and jobs by innovative healthcare policy favouring a preventive orientation of healthcare. The prevention and control of risk factors for chronic diseases, as well as their potential impact on the quality of human capital as a union of health and education, are discussed. Human capital refers to health and education both of the individual, and of the population as a whol
Crises and collective socio-economic phenomena: simple models and challenges
Financial and economic history is strewn with bubbles and crashes, booms and
busts, crises and upheavals of all sorts. Understanding the origin of these
events is arguably one of the most important problems in economic theory. In
this paper, we review recent efforts to include heterogeneities and
interactions in models of decision. We argue that the Random Field Ising model
(RFIM) indeed provides a unifying framework to account for many collective
socio-economic phenomena that lead to sudden ruptures and crises. We discuss
different models that can capture potentially destabilising self-referential
feedback loops, induced either by herding, i.e. reference to peers, or
trending, i.e. reference to the past, and account for some of the phenomenology
missing in the standard models. We discuss some empirically testable
predictions of these models, for example robust signatures of RFIM-like herding
effects, or the logarithmic decay of spatial correlations of voting patterns.
One of the most striking result, inspired by statistical physics methods, is
that Adam Smith's invisible hand can badly fail at solving simple coordination
problems. We also insist on the issue of time-scales, that can be extremely
long in some cases, and prevent socially optimal equilibria to be reached. As a
theoretical challenge, the study of so-called "detailed-balance" violating
decision rules is needed to decide whether conclusions based on current models
(that all assume detailed-balance) are indeed robust and generic.Comment: Review paper accepted for a special issue of J Stat Phys; several
minor improvements along reviewers' comment
Size Doesn't Matter: Towards a More Inclusive Philosophy of Biology
notes: As the primary author, OâMalley drafted the paper, and gathered and analysed data (scientific papers and talks). Conceptual analysis was conducted by both authors.publication-status: Publishedtypes: ArticlePhilosophers of biology, along with everyone else, generally perceive life to fall into two broad categories, the microbes and macrobes, and then pay most of their attention to the latter. âMacrobeâ is the word we propose for larger life forms, and we use it as part of an argument for microbial equality. We suggest that taking more notice of microbes â the dominant life form on the planet, both now and throughout evolutionary history â will transform some of the philosophy of biologyâs standard ideas on ontology, evolution, taxonomy and biodiversity. We set out a number of recent developments in microbiology â including biofilm formation, chemotaxis, quorum sensing and gene transfer â that highlight microbial capacities for cooperation and communication and break down conventional thinking that microbes are solely or primarily single-celled organisms. These insights also bring new perspectives to the levels of selection debate, as well as to discussions of the evolution and nature of multicellularity, and to neo-Darwinian understandings of evolutionary mechanisms. We show how these revisions lead to further complications for microbial classification and the philosophies of systematics and biodiversity. Incorporating microbial insights into the philosophy of biology will challenge many of its assumptions, but also give greater scope and depth to its investigations
National identity predicts public health support during a global pandemic
Changing collective behaviour and supporting non-pharmaceutical interventions is an important component in mitigating virus transmission during a pandemic. In a large international collaboration (Study 1, Nâ=â49,968 across 67 countries), we investigated self-reported factors associated with public health behaviours (e.g., spatial distancing and stricter hygiene) and endorsed public policy interventions (e.g., closing bars and restaurants) during the early stage of the COVID-19 pandemic (April-May 2020). Respondents who reported identifying more strongly with their nation consistently reported greater engagement in public health behaviours and support for public health policies. Results were similar for representative and non-representative national samples. Study 2 (Nâ=â42 countries) conceptually replicated the central finding using aggregate indices of national identity (obtained using the World Values Survey) and a measure of actual behaviour change during the pandemic (obtained from Google mobility reports). Higher levels of national identification prior to the pandemic predicted lower mobility during the early stage of the pandemic (râ=ââ0.40). We discuss the potential implications of links between national identity, leadership, and public health for managing COVID-19 and future pandemics.publishedVersio
Mapping and characterization of structural variation in 17,795 human genomes
A key goal of whole-genome sequencing for studies of human genetics is to interrogate all forms of variation, including single-nucleotide variants, small insertion or deletion (indel) variants and structural variants. However, tools and resources for the study of structural variants have lagged behind those for smaller variants. Here we used a scalable pipeline1 to map and characterize structural variants in 17,795 deeply sequenced human genomes. We publicly release site-frequency data to create the largest, to our knowledge, whole-genome-sequencing-based structural variant resource so far. On average, individuals carry 2.9 rare structural variants that alter coding regions; these variants affect the dosage or structure of 4.2 genes and account for 4.0â11.2% of rare high-impact coding alleles. Using a computational model, we estimate that structural variants account for 17.2% of rare alleles genome-wide, with predicted deleterious effects that are equivalent to loss-of-function coding alleles; approximately 90% of such structural variants are noncoding deletions (mean 19.1 per genome). We report 158,991 ultra-rare structural variants and show that 2% of individuals carry ultra-rare megabase-scale structural variants, nearly half of which are balanced or complex rearrangements. Finally, we infer the dosage sensitivity of genes and noncoding elements, and reveal trends that relate to element class and conservation. This work will help to guide the analysis and interpretation of structural variants in the era of whole-genome sequencing
An evolutionary phenomenology of resilience
Purpose: The purpose of the paper is to set out an evolutionary schema for organizational resilience using the established emergent autopoiesis coherence (EAC) framework, with empirical reference to the European Parliamentâs development of institutional capacities since its foundation in 1952 as the Common Assembly of the European Coal and Steel Community (CA-ECSC). Design/methodology/approach: The logic is categorical-synthetic and second-order cybernetic, implicitly underlain by a correspondence theory of truth united with a coherentism based in the epistemology of complex systems. Findings: The European Parliament has constructed itself as a resilient organization, but the process has entailed over-learning of past lessons, creating behavioral syndromes of dysfunction in the face of new challenges. Research limitations/implications: The work contrasts antifragility with resilience and suggests a new approach to it. Practical implications: The analytical framework and conclusions hold value for the practical design of resilient organizations. Social implications: The groundwork of the EACâs conceptual framework is laid, and the basis for applying it to human and other naturally occurring societies is established. Originality/value: K.W. Deutschâs mid-twentieth century work on cybernetic-based learning in political systems is reconstructed, updated and applied to twenty-first century political phenomena. The insights are validated, and the analytical frameworkâs robustness is demonstrated
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