2,232 research outputs found

    Rotational Spectral Unmixing of Exoplanets: Degeneracies between Surface Colors and Geography

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    Unmixing the disk-integrated spectra of exoplanets provides hints about heterogeneous surfaces that we cannot directly resolve in the foreseeable future. It is particularly important for terrestrial planets with diverse surface compositions like Earth. Although previous work on unmixing the spectra of Earth from disk-integrated multi-band light curves appeared successful, we point out a mathematical degeneracy between the surface colors and their spatial distributions. Nevertheless, useful constraints on the spectral shape of individual surface types may be obtained from the premise that albedo is everywhere between 0 and 1. We demonstrate the degeneracy and the possible constraints using both mock data based on a toy model of Earth, as well as real observations of Earth. Despite the severe degeneracy, we are still able to recover an approximate albedo spectrum for an ocean. In general, we find that surfaces are easier to identify when they cover a large fraction of the planet and when their spectra approach zero or unity in certain bands.Comment: 11 pages, 7 figures, published in AJ. Minor text updates from previous versio

    How well-proportioned are lens and prism spaces?

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    The CMB anisotropies in spherical 3-spaces with a non-trivial topology are analysed with a focus on lens and prism shaped fundamental cells. The conjecture is tested that well proportioned spaces lead to a suppression of large-scale anisotropies according to the observed cosmic microwave background (CMB). The focus is put on lens spaces L(p,q) which are supposed to be oddly proportioned. However, there are inhomogeneous lens spaces whose shape of the Voronoi domain depends on the position of the observer within the manifold. Such manifolds possess no fixed measure of well-proportioned and allow a predestined test of the well-proportioned conjecture. Topologies having the same Voronoi domain are shown to possess distinct CMB statistics which thus provide a counter-example to the well-proportioned conjecture. The CMB properties are analysed in terms of cyclic subgroups Z_p, and new point of view for the superior behaviour of the Poincar\'e dodecahedron is found

    Nuclear Magnetic Resonance and Hyperfine Structure

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    Contains reports on four research projects

    Protein sequence entropy is closely related to packing density and hydrophobicity

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    We investigated the correlation between the Shannon information entropy, ‘sequence entropy’, with respect to the local flexibility of native globular proteins as described by inverse packing density. These are determined at each residue position for a total set of 130 query proteins, where sequence entropies are calculated from each set of aligned residues. For the accompanying aggregate set of 130 alignments, a strong linear correlation is observed between the calculated sequence entropy and the corresponding inverse packing density determined at an associated residue position. This region of linearity spans the range of Cα packing densities from 12 to 25 amino acids within a sphere of 9 Å radius. Three different hydrophobicity scales all mimic the behavior of the sequence entropies. This confirms the idea that the ability to accommodate mutations is strongly dependent on the available space and on the propensity for each amino acid type to be buried. Future applications of these types of methods may prove useful in identifying both core and flexible residues within a protein

    Breaking up the band: European regulatory cooperation in a post-Brexit world

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    Since 1995, the European Medicines Agency (EMA) has progressed from harmonising regulation for human and veterinary medicines across the European Union Member State national competent authorities, to galvanising one of the most successful cooperative initiatives for regulation globally. Although the EMA is the focal point for stakeholders, regulation is delivered through the European medicines regulatory network, in which national authorities, like the UK’s Medicines & Healthcare products Regulatory Agency (MHRA), contribute. As with any collaboration, contributions by individual members vary, and the MHRA has been noted as an innovative and highly productive member of the network. Progress in regulation not only in Europe – but also around the world through convergence – can be attributed to this unique European cooperation. The decision by the UK to leave the European Union threatens to mark the end of this cooperation; we argue here that the best decision is to maintain regulatory cooperation under new structures

    Structural Synthesis for GXW Specifications

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    We define the GXW fragment of linear temporal logic (LTL) as the basis for synthesizing embedded control software for safety-critical applications. Since GXW includes the use of a weak-until operator we are able to specify a number of diverse programmable logic control (PLC) problems, which we have compiled from industrial training sets. For GXW controller specifications, we develop a novel approach for synthesizing a set of synchronously communicating actor-based controllers. This synthesis algorithm proceeds by means of recursing over the structure of GXW specifications, and generates a set of dedicated and synchronously communicating sub-controllers according to the formula structure. In a subsequent step, 2QBF constraint solving identifies and tries to resolve potential conflicts between individual GXW specifications. This structural approach to GXW synthesis supports traceability between requirements and the generated control code as mandated by certification regimes for safety-critical software. Synthesis for GXW specifications is in PSPACE compared to 2EXPTIME-completeness of full-fledged LTL synthesis. Indeed our experimental results suggest that GXW synthesis scales well to industrial-sized control synthesis problems with 20 input and output ports and beyond.Comment: The long (including appendix) version being reviewed by CAV'16 program committee. Compared to the submitted version, one author (out of her wish) is moved to the Acknowledgement. (v2) Corrected typos. (v3) Add an additional remark over environment assumption and easy corner case

    Common peroneal nerve palsy complicating knee dislocation and bicruciate ligaments tears

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    SummaryIntroductionThe occurrence rate of common peroneal nerve (CPN) palsy associated with knee dislocation or bicruciate ligament injury ranges from 10 to 40%. The present study sought first to describe the anatomic lesions encountered and their associated prognoses and second to recommend adequate treatment strategy based on a prospective multicenter observational series of knee ligament trauma cases.Material and methodsTwelve out of 67 knees treated for dislocation or bicruciate lesion presented associated CPN palsy: two females, 10 males; mean age, 32 years. Four sports injuries, three traffic accidents and five other etiologies led to seven complete dislocations and five bicruciate ruptures. Four cases involved associated popliteal artery laceration ischemia; one of the dislocations was open. Paralysis was total in eight cases and partial in four. There were two complete ruptures, three contusions with CPN in continuity stretch lesions and three macroscopically normal aspects.ResultsAt a minimum 1 year's follow-up, regardless of the initial surgical technique performed, recovery was complete in six cases, partial (in terms of motor function) in one and absent in five. Without specific CPN surgery, spontaneous recovery was partial in one case, complete in two and absent in none. Following simple emergency or secondary neurolysis, remission was total in four cases and absent in one. Three nerve grafts were all associated with non-recovery.DiscussionThe present results agree with literature findings. Palsy rates varied with trauma circumstances and departmental recruitment. Neurologic impairment was commensurate to ligamentary damages. The anatomic status of the CPN, subjected to violent traction by dislocation, was the most significant prognostic factor for neurologic recovery. In about 25% of dislocations, contusion-elongation over several centimeters was associated with as poor a prognosis as total rupture. CPN neurolysis is recommended when early clinical and EMG recovery fails to progress and/or in case of lateral ligamentary reconstruction. Possible peripheral nerve impairment needs to be included in the overall functional assessment of treatment for severe ligaments injuries and knee dislocation.Level of evidenceLevel IV, prospective study
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