181 research outputs found
Comparing RNA structures using a full set of biologically relevant edit operations is intractable
7 pagesArc-annotated sequences are useful for representing structural information of RNAs and have been extensively used for comparing RNA structures in both terms of sequence and structural similarities. Among the many paradigms referring to arc-annotated sequences and RNA structures comparison (see \cite{IGMA_BliDenDul08} for more details), the most important one is the general edit distance. The problem of computing an edit distance between two non-crossing arc-annotated sequences was introduced in \cite{Evans99}. The introduced model uses edit operations that involve either single letters or pairs of letters (never considered separately) and is solvable in polynomial-time \cite{ZhangShasha:1989}. To account for other possible RNA structural evolutionary events, new edit operations, allowing to consider either silmutaneously or separately letters of a pair were introduced in \cite{jiangli}; unfortunately at the cost of computational tractability. It has been proved that comparing two RNA secondary structures using a full set of biologically relevant edit operations is {\sf\bf NP}-complete. Nevertheless, in \cite{DBLP:conf/spire/GuignonCH05}, the authors have used a strong combinatorial restriction in order to compare two RNA stem-loops with a full set of biologically relevant edit operations; which have allowed them to design a polynomial-time and space algorithm for comparing general secondary RNA structures. In this paper we will prove theoretically that comparing two RNA structures using a full set of biologically relevant edit operations cannot be done without strong combinatorial restrictions
Nearest constrained circular words
In this paper, we study circular words arising in the development of equipment using shields in brachytherapy. This equipment has physical constraints that have to be taken into consideration. From an algorithmic point of view, the problem can be formulated as follows: Given a circular word, find a constrained circular word of the same length such that the Manhattan distance between these two words is minimal. We show that we can solve this problem in pseudo polynomial time (polynomial time in practice) using dynamic programming
Median of an odd number of permutations
International audienceGiven m permutations Ï1, Ï2 . . . Ïm of {1, 2, . . . , n} and a distance function d, the median problem is to find a permutation Ï â that is the "closest" of the m given permutations. Here, we study the problem under the Kendall-Ï distance that counts the number of pairwise disagreements between permutations. This problem is also known, in the context of rank aggregation, as the Kemeny Score Problem and has been proved to be NP-hard when m â„ 4. This article is an extension of [4], where some nice combinatorial properties of the case m = 3 where stated without proof, to the general case m â„ 3, m odd
Bonifacio â Piantarella
La campagne de fouille programmĂ©e de la villa romaine de Piantarella (Bonifacio) sâinscrit dans le cadre dâun projet plus large, le PCR « Les Bouches de Bonifacio Ă lâĂ©poque romaine : approches archĂ©ologique et gĂ©oarchĂ©ologique ». Cette annĂ©e, une grande partie des moyens a Ă©tĂ© consacrĂ©e Ă la fouille avec lâouverture de sept sondages de vĂ©rification. Par ailleurs, trois secteurs ont fait lâobjet dâune fouille approfondie, notamment au niveau des bains (piĂšces A10 et A12) (fig. 1) et au sein d..
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TAO Conceptual Design Report: A Precision Measurement of the Reactor Antineutrino Spectrum with Sub-percent Energy Resolution
The Taishan Antineutrino Observatory (TAO, also known as JUNO-TAO) is a
satellite experiment of the Jiangmen Underground Neutrino Observatory (JUNO). A
ton-level liquid scintillator detector will be placed at about 30 m from a core
of the Taishan Nuclear Power Plant. The reactor antineutrino spectrum will be
measured with sub-percent energy resolution, to provide a reference spectrum
for future reactor neutrino experiments, and to provide a benchmark measurement
to test nuclear databases. A spherical acrylic vessel containing 2.8 ton
gadolinium-doped liquid scintillator will be viewed by 10 m^2 Silicon
Photomultipliers (SiPMs) of >50% photon detection efficiency with almost full
coverage. The photoelectron yield is about 4500 per MeV, an order higher than
any existing large-scale liquid scintillator detectors. The detector operates
at -50 degree C to lower the dark noise of SiPMs to an acceptable level. The
detector will measure about 2000 reactor antineutrinos per day, and is designed
to be well shielded from cosmogenic backgrounds and ambient radioactivities to
have about 10% background-to-signal ratio. The experiment is expected to start
operation in 2022
BibliothĂšques publiques britanniques contemporaines
Cet ouvrage se propose de revenir sur les fermetures massives, depuis 2010, des bibliothĂšques publiques en Grande-Bretagne. Quelle a Ă©tĂ© la chronologie des plus de 300 fermetures de sites ? Comment en comprendre lâhistoire et les logiques ? Pour la premiĂšre fois accessible aux lecteurs français, une documentation spĂ©cialisĂ©e, traduite et Ă©ditorialisĂ©e, permet de comprendre les enjeux du dĂ©bat sur la lecture publique dans un pays historiquement fer de lance pour son rĂ©seau de bibliothĂšques. DirigĂ© par CĂ©cile Touitou, assistĂ©e de Karine Lespinasse, le livre rĂ©unit un collectif dâauteurs experts, français et britanniques
Nouvelles donnĂ©es sur lâagglomĂ©ration antique dâ<i>Epomanduodurum</i> (Mandeure et Mathay, Doubs)
International audienceDem antiken Mandeure-Mathay (Epomanduodurum), dem aufgrund seiner GröĂe und seiner bedeutenden Monumentalbauten im Sequanerland der zweite Platz nach dem Civitas-Hauptort Besançon zukommt, ist seit 2001 ein pluridisziplinĂ€res Forschungsprojekt gewidmet. Im AnschluĂ an einen im Jahrgang 2007 dieser Zeitschrift vorgelegten Beitrag berichtet das vorliegende Dossier ĂŒber die Forschungen der Jahre 2005 bis 2011. Parallel zur WeiterfĂŒhrung und Vertiefung der im Bereich der Kult- und Monumentalbauten begonnenen Arbeiten, trieb das Forschungsteam wĂ€hrend dieses zweiten Projektabschnittes verschiedene Studien zur gesamten antiken Stadtanlage und der sie umgebenden Mikroregion voran. Diese Untersuchungen liefern neue Einsichten zur Entstehung, Entwicklung und zum Niedergang von Epomanduodurum und tragen zu einem vertieften VerstĂ€ndnis der Gestalt dieser Stadt und ihrer religiösen, ökonomischen und sozialen Organisation im Zeitraum vom Ende der Eisenzeit bis zum FrĂŒhmittelalter bei.A collective research program is studying since 2001 the ancient agglomeration of Mandeure-Mathay (Epomanduodurum), considered as second one after the chief town Besançon, in the Sequani territory, by its size and its impressive monumental buildings. This article, following a previous paper published in Gallia in 2007, draws up a report of the researches completed between 2005 and 2011. In this second stage, alongside the ongoing in-depth investigations on cult and monumental area, the PCR (Collective Program Research) team intensified its different studies and researches on the ancient agglomeration and its microregional environment. These studies lead to a better understanding of the appearance, development and decline of Epomanduodurum ; a better knowledge of its morphology, and its religious, economic and social organization between the end of the Iron Age and the Early Middle Ages.LâagglomĂ©ration antique de Mandeure-Mathay (Epomanduodurum), considĂ©rĂ©e comme la seconde du pays sĂ©quane par ses dimensions et lâampleur de sa parure monumentale, derriĂšre la capitale de citĂ©, Besançon, fait lâobjet dâun programme collectif de recherche (PCR), pluridisciplinaire, depuis 2001. Le prĂ©sent dossier, qui fait suite Ă un prĂ©cĂ©dent article paru dans Gallia en 2007, dresse un bilan des recherches rĂ©alisĂ©es entre 2005 et 2011. Dans cette seconde Ă©tape, parallĂšlement Ă la poursuite et Ă lâapprofondissement des actions engagĂ©es sur le secteur cultuel et monumental, lâĂ©quipe du PCR a accentuĂ© les Ă©tudes et investigations de diverses natures portant sur lâensemble de lâagglomĂ©ration antique et sur lâespace microrĂ©gional dans lequel celle-ci sâinsĂšre. Ces recherches aboutissent Ă une meilleure comprĂ©hension des modalitĂ©s dâĂ©mergence, de dĂ©veloppement et de dĂ©clin de la ville dâEpomanduodurum, et Ă une connaissance plus approfondie de sa morphologie et de son organisation religieuse, Ă©conomique et sociale, entre la fin de lâĂąge du Fer et le haut Moyen Ăge
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