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

A generalized bayesian inference method for constraining the interiors of super Earths and sub-Neptunes

We aim to present a generalized Bayesian inference method for constraining interiors of super Earths and sub-Neptunes. Our methodology succeeds in quantifying the degeneracy and correlation of structural parameters for high dimensional parameter spaces. Specifically, we identify what constraints can be placed on composition and thickness of core, mantle, ice, ocean, and atmospheric layers given observations of mass, radius, and bulk refractory abundance constraints (Fe, Mg, Si) from observations of the host star's photospheric composition. We employed a full probabilistic Bayesian inference analysis that formally accounts for observational and model uncertainties. Using a Markov chain Monte Carlo technique, we computed joint and marginal posterior probability distributions for all structural parameters of interest. We included state-of-the-art structural models based on self-consistent thermodynamics of core, mantle, high-pressure ice, and liquid water. Furthermore, we tested and compared two different atmospheric models that are tailored for modeling thick and thin atmospheres, respectively. First, we validate our method against Neptune. Second, we apply it to synthetic exoplanets of fixed mass and determine the effect on interior structure and composition when (1) radius, (2) atmospheric model, (3) data uncertainties, (4) semi-major axes, (5) atmospheric composition (i.e., a priori assumption of enriched envelopes versus pure H/He envelopes), and (6) prior distributions are varied. Our main conclusions are: [...]Comment: Astronomy & Astrophysics, 597, A37, 17 pages, 11 figure

Toolkit for simulated commissioning of storage-ring light sources and application to the advanced light source upgrade accumulator

We present a new accelerator toolbox (AT)-based toolkit for simulating the commissioning of light-source storage rings. The toolkit provides a framework for supporting high-level scripts to represent with realism the various procedures (e.g., orbit and optics correction, beam-based alignment, etc.) encountered during commissioning and is designed to mirror as closely as possible the reality as seen from the control room. Emphasis is placed on the inclusion of a comprehensive set of error sources and faithful modeling of beam diagnostics. The toolkit capabilities are demonstrated in an application to the recent design and commissioning studies of the Advanced Light Source Upgrade (ALS-U) Accumulator Ring, a short-time successful commissioning of which will be critical to the overall ALS-U project success

A statistical study of transient events in the outer dayside magnetosphere

The AMPTE CCE satellite frequently observed transient (1 ≤ τ ≤ 8 min) events marked by magnetic field strength increases and bipolar magnetic field signatures (peak-to-peak amplitudes ≥ 4 nT) while in the outer dayside magnetosphere. We report a survey of 59 prominant events observed from August to November 1984. The bipolar signatures and minimum variance analysis reveal that most events move poleward and antisunward, except in the immediate vicinity of local noon. Here the motion of the events appears to be better governed by the spiral/orthospiral interplanetary magnetic field (IMF) orientation than magnetic curvature forces associated with IMF By. The IMF orientation appears to have little or no influence on event occurrence or orientation. We interpret the events in terms of solar wind/foreshock pressure pulse induced ripples on the magnetopause surface. Our results can be reconciled with those obtained in previous studies which made use of ISEE 1/2, AMPTE IRM, and AMPTE UKS observations if pressure pulses produce large-amplitude events and bursty merging (or reconnection) produces small-amplitude events

Is there still a role for genome-wide association studies? Investigating the genetic architecture of primary open-angle glaucoma and associated phenotypes

Despite the success of GWASs in the recent years, the genetic architecture of complex diseases, such as primary open-angle glaucoma is yet to be understood. The purpose of this thesis is to gain a better understanding of primary open-angle glaucoma using genetic association studies on several quantitative traits, such as intraocular pressure and optic nerve measurements. Collaborative efforts through extensive meta-analysis will help to increase the power of genetic association studies to identify novel variants for intraocular pressure and optic nerve parameters. In addition, gene-set enrichment analysis on the results of these meta-analyses may also help to shed a light on the mechanisms underlying glaucoma pathogenesis. Intraocular pressure and optic nerve cupping are not independent and they act together to determine the disease. Genetic association studies that combine information from different quantitative traits may help to identify novel genes affecting glaucoma susceptibility. In addition, epistatic interactions may also play a role in determining glaucoma endophenotypes variation and may help to identify novel loci affecting primary open-angle glaucoma susceptibility. Finally, primary open-angle glaucoma has been also associated with Alzheimer's disease, particularly the decrease of retinal ganglion cells. Elucidating the genetic underlying retinal nerve fibre layer and its relationship with Alzheimer's disease may help to discover and understand neurodegenerative mechanisms affecting primary open-angle glaucoma

Characterization of the benthic environment of a coastal area adjacent to an oil refinery, Todos os Santos Bay (NE-Brazil)

Com o intuito de determinar as características sedimentológicas e físico-químicas do ambiente bentônico e também o nível, distribuição e prováveis fontes dos hidrocarbonetos alifáticos e policíclicos aromáticos, foram coletadas amostras de sedimento em 28 estações localizadas na porção nordeste da Baía de Todos os Santos. A região central e leste da área de estudo apresentaram características de ambientes deposicionais com predomínio de silte e argila e com maiores teores de carbono orgânico total, nitrogênio e enxofre. As razões C/N variaram entre 8,8 e 27,6 indicando uma origem mista da matéria orgânica com contribuições marinha e continental relativamente variáveis. As concentrações de hidrocarbonetos alifáticos totais variaram entre 1,56 e 246,91 µg.g-1 de sedimento seco, correspondendo as maiores concentrações às estações localizadas na região central e leste da área de estudo. A Mistura Complexa não Resolvida (UCM) representou entre 60 e 90% dos hidrocarbonetos alifáticos totais, indicando um alto grau de contribuição antrópica e a presença de resíduos de petróleo degradado. As concentrações de hidrocarbonetos policíclicos aromáticos totais variaram de 8 a 4163 ng.g-1 de sedimento seco. A maior concentração de hidrocarbonetos policíclicos aromáticos foi registrada na estação 5 situada na área adjacente à refinaria de petróleo.In order to determine the sedimentological and physico-chemical characteristics of the benthic environment and also the level, distribution and probable sources of aliphatic and polycyclic aromatic hydrocarbons, sediment samples were collected at 28 stations in the northeast portion of Todos os Santos Bay. The centre and the east region of the study area showed characteristics of depositional environments with the predominance of silt and clay and high percentages of TOC, nitrogen and sulphur. The molar C/N ratios varied between 8.8 and 27.6 indicating a mixed origin of organic matter with variable marine and continental contributions. Total aliphatic hydrocarbon concentrations ranged between 1.56 and 246.91 µg.g-1 dry weight, corresponding the high concentrations to the stations situated in the centre and in the east region of the study area. The UCM represented between 60 and 96% of the total aliphatic hydrocarbons, indicating a high degree of anthropogenic contribution and the presence of petroleum degraded residues. Total PAH concentrations varied from 8 to 4163 ng.g-1 dry weight. The highest total PAH concentration was recorded at station 5 situated adjacent to the oil refinery

Genomic and geographical structure of human cytomegalovirus

Human cytomegalovirus (CMV) has infected humans since the origin of our species and currently infects most of the world’s population. Variability between CMV genomes is the highest of any human herpesvirus, yet large portions of the genome are conserved. Here, we show that the genome encodes 74 regions of relatively high variability each with 2 to 8 alleles. We then identified two patterns in the CMV genome. Conserved parts of the genome and a minority (32) of variable regions show geographic population structure with evidence for African or European clustering, although hybrid strains are present. We find no evidence that geographic segregation has been driven by host immune pressure affecting known antigenic sites. Forty-two variable regions show no geographical structure, with similar allele distributions across different continental populations. These “nongeographical” regions are significantly enriched for genes encoding immunomodulatory functions suggesting a core functional importance. We hypothesize that at least two CMV founder populations account for the geographical differences that are largely seen in the conserved portions of the genome, although the timing of separation and direction of spread between the two are not clear. In contrast, the similar allele frequencies among 42 variable regions of the genome, irrespective of geographical origin, are indicative of a second evolutionary process, namely balancing selection that may preserve properties critical to CMV biological function. Given that genetic differences between CMVs are postulated to alter immunogenicity and potentially function, understanding these two evolutionary processes could contribute important information for the development of globally effective vaccines and the identification of novel drug targets

Reply to Comment on:"Nonmonotonic d_{x^2-y^2} Superconducting Order Parameter in Nd_{2-x}Ce_xCuO_4"

We confirm that all the results of scanning SQUID, tunneling, ARPES, penetration depth and Raman experiments are consistent with a nonmonotonic d_{x^2-y^2} superconducting order parameter proposed in Phys. Rev. Lett., 88, 107002 (2002).Comment: Reply to Comment by F. Venturini, R. Hackl, and U. Michelucci cond-mat/020541

Origin of ferroelectricity in the multiferroic barium fluorides BaMF4

We present a first principles study of the series of multiferroic barium fluorides with the composition BaMF4, where M is Mn, Fe, Co, or Ni. We discuss trends in the structural, electronic, and magnetic properties, and we show that the ferroelectricity in these systems results from the "freezing in" of a single unstable polar phonon mode. In contrast to the case of the standard perovskite ferroelectrics, this structural distortion is not accompanied by charge transfer between cations and anions. Thus, the ferroelectric instability in the multiferroic barium fluorides arises solely due to size effects and the special geometrical constraints of the underlying crystal structure.Comment: 8 pages, 6 figures, 3 table