Identification of the prebiotic translation apparatus within the contemporary ribosome

A structural element that could have existed independently in the prebiotic era was identified at the active site of the contemporary ribosome. It is suggested to have functioned as a proto-ribosome catalyzing peptide bond formation and non-coded elongation in the same manner that contemporary ribosomes exert positional catalysis, namely by accommodating the reactants in stereochemistry favourable for inline nucleophilic attack. This simple apparatus is a dimer of self-folding RNA units that could have assembled spontaneously into a symmetrical pocket-like structure, sufficiently efficient to be preserved throughout evolution as the active site of modern ribosomes, thus presenting a conceivable starting point for translation.Here we discuss the proto-ribosome emergence hypothesis and show that the tendency for dimerization, a prerequisite for obtaining the catalytic centre, is linked to the fold of its two components, indicating functional selection at the molecular level in the prebiotic era and supporting the existence of dimeric proto-ribosome

Investigation of organic adhesives for hybrid microcircuits

The properties of organic adhesives were investigated to acquire information for a guideline document regarding the selection of adhesives for use in high reliability hybrid microcircuits. Specifically, investigations were made of (1) alternate methods for determining the outgassing of cured adhesives, (2) effects of long term aging at 150 C on the electrical properties of conductive adhesives, (3) effects of shelf life age on adhesive characteristics, (4) bond strengths of electrically conductive adhesives on thick film gold metallization, (5) a copper filled adhesive, (6) effects of products outgassed from cured adhesives on device electrical parameters, (7) metal migration from electrically conductive adhesives, and (8) ionic content of electrically insulative adhesives. The tests performed during these investigations are described, and the results obtained are discussed

Montpelier Community Nursery

Montpelier Community Nursery is a small building in Kentish Town, London designed for Camden Community Nurseries. The project has wide reach as a model for participatory design processes in dense urban neighbourhoods. It responds to a number of research questions: How can the design of a small public building serve as an instrument of community building and urban regeneration? What responsible environmental strategies can be incorporated into the design of a nursery? How can natural play be promoted in the design of a nursery? How can the sustainability of a nursery be assured? How can the autobiography of the building be recorded? Boulanger was involved in all stages of the project, generating community awareness, bringing together different parties to participate in its design, fundraising, designing, supervising the building’s construction and recording and disseminating the process. The new building was designed around a flexible space opening onto a wooded outdoor area. Daylight is brought into the building through strip windows located within the roof with a north-south orientation, spanning the floor plan diagonally. Deep overhangs allow passive solar heat gain during times of the year as needed, but block out high summer sun. The superstructure is made of a pre-fabricated solid timber panel system, which facilitated an efficient building sequence. The project was recorded and disseminated through film, photographic documentation and exhibition, a children-focused workshop and a collaborative project of site visits with local primary school children. The building has been widely lauded, receiving a 2013 RIBA London Regional Award, a 2013 RIBA National Award and the 2013 Steven Lawrence Prize, which rewards the best example of a project with a construction budget of less than £1 million. This output will also be returned by Yeoryia Manolopoulou for University College London

New Acceleration of Nearly Optimal Univariate Polynomial Root-findERS

Univariate polynomial root-finding has been studied for four millennia and is still the subject of intensive research. Hundreds of efficient algorithms for this task have been proposed. Two of them are nearly optimal. The first one, proposed in 1995, relies on recursive factorization of a polynomial, is quite involved, and has never been implemented. The second one, proposed in 2016, relies on subdivision iterations, was implemented in 2018, and promises to be practically competitive, although user's current choice for univariate polynomial root-finding is the package MPSolve, proposed in 2000, revised in 2014, and based on Ehrlich's functional iterations. By proposing and incorporating some novel techniques we significantly accelerate both subdivision and Ehrlich's iterations. Moreover our acceleration of the known subdivision root-finders is dramatic in the case of sparse input polynomials. Our techniques can be of some independent interest for the design and analysis of polynomial root-finders.Comment: 89 pages, 5 figures, 2 table

Design guidelines for use of adhesives and organic coatings in hybrid microcircuits

A study was conducted to investigate the reliability of organic adhesives in hybrid microcircuits. The objectives were twofold: (1) to identify and investigate problem areas that could result from the use of organic adhesives and (2) to develop evaluation tests to quantify the extent to which these problems occur for commercially available adhesives. Efforts were focused on electrically conductive adhesives. Also, a study was made to evaluate selected organic coatings for contamination protection for hybrid microcircuits

Algebras related to posets of hyperplanes

We compare two noncommutative algebras which are related to arrangements of hyperplanes. For three special arrangements the induced approximately finite dimensional $C^*$-algebra and the graded Orlik-Solomon-algebra are investigated

A revised radiometric calibration for the Hinode/EIS instrument

A preliminary assessment of the in-flight radiometric calibration of the Hinode EUV Imaging Spectrometer (EIS) is presented. This is done with the line ratio technique applied to a wide range of observations of the quiet Sun, active regions and flares from 2006 until 2012. The best diagnostic lines and the relevant atomic data are discussed in detail. Radiances over the quiet Sun are also considered, with comparisons with previous measurements. Some departures in the shapes of the ground calibration responsivities are found at the start of the mission. These shapes do not change significantly over time, with the exception of the shorter wavelengths of the EIS short-wavelength (SW) channel, which shows some degradation. The sensitivity of the SW channel at longer wavelengths does not show significant degradation, while that of the long-wavelength (LW) channel shows a significant degradation with time. By the beginning of 2010 the responsivity of the LW channel was already a factor of two or more lower than the values measured on the ground. A first-order correction is proposed. With this correction, the main ratios of lines in the two channels become constant to within a relative 20%, and the He II 256 A radiances over the quiet Sun also become constant over time. This correction removes long-standing discrepancies for a number of lines and ions, in particular those involving the strongest Fe X, Fe XIII, Fe XIV, Fe XVII, and Fe XXIV lines, where discrepancies of factors of more than two were found. These results have important implications for various EIS science analyses, in particular for measurements of temperatures, emission measures and elemental abundances.Comment: Accepted for publication in A&A (under minor revision

Spherical Functions on Riemannian Symmetric Spaces

This paper deals with some simple results about spherical functions of type $\delta$, namely new integral formulas, new results about behavior at infinity and some facts about the related $C_\sigma$ functions.Comment: 15 page