Bayesian analysis of interiors of HD 219134b, Kepler-10b, Kepler-93b, CoRoT-7b, 55 Cnc e, and HD 97658b using stellar abundance proxies

Using a generalized Bayesian inference method, we aim to explore the possible interior structures of six selected exoplanets for which planetary mass and radius measurements are available in addition to stellar host abundances: HD~219134b, Kepler-10b, Kepler-93b, CoRoT-7b, 55~Cnc~e, and HD~97658b. We aim to investigate the importance of stellar abundance proxies for the planetary bulk composition (namely Fe/Si and Mg/Si) on prediction of planetary interiors. We performed a full probabilistic Bayesian inference analysis to formally account for observational and model uncertainties while obtaining confidence regions of structural and compositional parameters of core, mantle, ice layer, ocean, and atmosphere. We determined how sensitive our parameter predictions depend on (1) different estimates of bulk abundance constraints and (2) different correlations of bulk abundances between planet and host star. [...] Although the possible ranges of interior structures are large, structural parameters and their correlations are constrained by the sparse data. The probability for the tested exoplanets to be Earth-like is generally very low. Furthermore, we conclude that different estimates of planet bulk abundance constraints mainly affect mantle composition and core size.Comment: Astronomy & Astrophysics, 597, A38 (15 pages, 9 figures

STS: how come and why not

A proposal to encourage 'simple' secutitisation (bundling and selling on of debt) is before the European Parliament. The proposal, as forwarded by the European Commission and the Council, raises question about the choice of securitisation (debt+complexity) as a ‘post-crisis’ policy instrument. And could Members of the European Parliament explain all this to citizens? (the “What Were You Thinking?” test). Answers depend on one’s preferred cognitive framing. This presentation moves on from the evaluative debate (securitisation is good/bad/it depends), to a historical enquiry into the 'post-crisis' re-emergence of securitisation. Taking an institutionalist approach, it identifies EU public institutions - not the market - as the re-starters of securitisation in Europe

Regulatory herding versus democratic diversity: history and prospects

Regulatory convergence — within the E.U., across the Atlantic and internationally — is conventionally represented as not only benign but also as essential in crisis prevention. This paper articulates a different frame of reference: one in which regulators “crowd,” “herd” and sometimes merge, so mimicking and exacerbating financial market tendencies toward similarity and contagion, and drawing regulators and markets into the same vortex. The paper looks at some of the historical and contemporary circumstances in the U.K., wider E.U. and the U.S. that have given reign to these tendencies and also at some aspects of regulatory architecture and governance that reduce such tendencies. It mentions pre-crisis tendencies to regulatory subservience to financial markets, with such subservience having a deep history in the U.K. and a shorter one in the U.S.; so-called command regulation, which has the potential to either deepen subservience or transcend it; and the institutional preconditions for permanent regulatory vigilance, such as democratic appointment of heads of agencies. The paper concludes by pondering the prospects for the democratic direction of financial market regulation, in terms of its distributional logics and extraterritoriality

Banking culture and collective responsibility: A memorandum to the UK Parliamentary Commission on Banking Standards

Basic assumptions • There is wide interest in connecting issues of (i) occupational culture, (ii) compliance/ misconduct, (iii) remuneration and (iv) clawback (the bonus/malus debate). • Individual-focussed measures (supervision, remuneration and measures in civil or criminal law) must be supplemented by a wider, whole-firm regulatory strategy. • Whilst attention has been drawn to ‘the tone at the top’, ‘the tone in the middle’ and ‘the tone at the bottom’ are as important. Collectively, mid- and lower-level staff see and know more than chief executives or boards. To reform culture, all levels need to be properly incentivised. • In cases of rule-breaking, recklessness or malfeasance, clawing back a proportion of past and/or present remuneration is a matter of economic justice. • However, questions about who to hold (co-)responsible and to target for recoveries need to be more imaginatively addressed than hitherto. Up to now, some of those working in the financial services industry have passively gained from the recklessness and misdemeanours of their peers – for example, through group bonuses – whilst not being at any risk of clawbacks unless they are also are flagrantly involved. All rewards for passive connivance should be withdrawn, indeed reversed. Recommendations • The Commission should recommend collective responsibility, financial accountability and clawbacks – applying laterally to co-workers of miscreants, as well as vertically to management. This would animate the occupational culture, incentivising all levels of banking staff, in a proactive and precautionary manner, to bring informal pressure to bear against reckless or improper practices and, where that fails, to trigger formal investigation, via reporting and whistleblowing. • A forthright approach would be to go for such linked cultural and remuneration reforms across the whole sector. A more tentative and exploratory step would be to use the (partly) publicly-owned banks as a testing ground. An alternative would be to require such reforms selectively, as conditions of settlement with regulators. If monitoring over time finds that the changes seem positive, then that could provide ammunition for wider change across the industry. Future work • Further thought needs to be given to the relationship between occupational culture within banking, and broader shifts of sentiment associated with the business cycle. • The relationship between (a) risk-taking and (b) the implicit public guarantees enjoyed by banks and liquidity support by central banks remains problematic

Coordinate representation of particle dynamics in AdS and in generic static spacetimes

We discuss the quantum dynamics of a particle in static curved spacetimes in a coordinate representation. The scheme is based on the analysis of the squared energy operator E^2, which is quadratic in momenta and contains a scalar curvature term. Our main emphasis is on AdS spaces, where this term is fixed by the isometry group. As a byproduct the isometry generators are constructed and the energy spectrum is reproduced. In the massless case the conformal symmetry is realized as well. We show the equivalence between this quantization and the covariant quantization, based on the Klein-Gordon type equation in AdS. We further demonstrate that the two quantization methods in an arbitrary (N+1)-dimensional static spacetime are equivalent to each other if the scalar curvature terms both in the operator E^2 and in the Klein-Gordon type equation have the same coefficient equal to (N-1)/(4N).Comment: 14 pages, no figures, typos correcte

Dynamic Programming for Graphs on Surfaces

We provide a framework for the design and analysis of dynamic programming algorithms for surface-embedded graphs on n vertices and branchwidth at most k. Our technique applies to general families of problems where standard dynamic programming runs in 2^{O(k log k)} n steps. Our approach combines tools from topological graph theory and analytic combinatorics. In particular, we introduce a new type of branch decomposition called "surface cut decomposition", generalizing sphere cut decompositions of planar graphs introduced by Seymour and Thomas, which has nice combinatorial properties. Namely, the number of partial solutions that can be arranged on a surface cut decomposition can be upper-bounded by the number of non-crossing partitions on surfaces with boundary. It follows that partial solutions can be represented by a single-exponential (in the branchwidth k) number of configurations. This proves that, when applied on surface cut decompositions, dynamic programming runs in 2^{O(k)} n steps. That way, we considerably extend the class of problems that can be solved in running times with a single-exponential dependence on branchwidth and unify/improve most previous results in this direction.Comment: 28 pages, 3 figure

Dynamic programming for graphs on surfaces

We provide a framework for the design and analysis of dynamic programming algorithms for surface-embedded graphs on n vertices and branchwidth at most k. Our technique applies to general families of problems where standard dynamic programming runs in 2O(k·log k). Our approach combines tools from topological graph theory and analytic combinatorics.Postprint (updated version

Constant mean curvature surfaces in AdS_3

We construct constant mean curvature surfaces of the general finite-gap type in AdS_3. The special case with zero mean curvature gives minimal surfaces relevant for the study of Wilson loops and gluon scattering amplitudes in N=4 super Yang-Mills. We also analyze properties of the finite-gap solutions including asymptotic behavior and the degenerate (soliton) limit, and discuss possible solutions with null boundaries.Comment: 19 pages, v2: minor corrections, to appear in JHE

Comparative study of gp130 cytokine effects on corticotroph AtT-20 cells - Redundancy or specificity of neuroimmunoendocrine modulators?

Objective: This comparative in vitro study examined the effects of all known gp130 cytokines on murine corticotroph AtT-20 cell function. Methods: Cytokines were tested at equimolar concentrations from 0.078 to 10 nM. Tyrosine phosphorylation of the signal transducer and activator of transcription ( STAT) 3 and STAT1, the STAT-dependent suppressor of cytokine signaling (SOCS)-3 promoter activity, SOCS-3 gene expression, STAT-dependent POMC promoter activity and adrenocorticotropic hormone ( ACTH) secretion were determined. Results: Leukemia inhibitory factor (LIF), human oncostatin M (OSM) and cardiotrophin (CT)-1 (LIFR/gp130 ligands), as well as ciliary neurotrophic factor ( CNTF) and novel neurotrophin1/B-cell stimulating factor-3 (CNTFRalpha/LIFR/gp130 ligands) are potent stimuli of corticotroph cells in vitro. In comparison, interleukin (IL)-6 (IL-6R/gp130 ligand) and IL-11 (IL-11R/gp130 ligand) exhibited only modest direct effects on corticotrophs, while murine OSM (OSMR/gp130 ligand) showed no effect. Conclusion: (i) CNTFR complex ligands are potent stimuli of corticotroph function, comparable to LIFR complex ligands; (ii) IL-6 and IL-11 are relatively weak direct stimuli of corticotroph function; (iii) differential effects of human and murine OSM suggest that LIFR/gp130 (OSMR type I) but not OSMR/gp130 (OSMR type II) are involved in corticotroph signaling. (iv) CT-1 has the hitherto unknown ability to stimulate corticotroph function, and (v) despite redundant immuno-neuroendocrine effects of different gp130 cytokines, corticotroph cells are preferably activated through the LIFR and CNTFR complexes. Copyright (C) 2004 S. Karger AG, Basel