4,608 research outputs found

    Crystallization in a dense suspension of self-propelled particles

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    Using Brownian dynamics computer simulations we show that a two-dimensional suspension of self-propelled ("active") colloidal particles crystallizes at sufficiently high densities. Compared to the equilibrium freezing of passive particles the freezing density is both significantly shifted and depends on the structural or dynamical criterion employed. In non-equilibrium the transition is accompanied by pronounced structural heterogeneities. This leads to a transition region between liquid and solid in which the suspension is globally ordered but unordered liquid-like "bubbles" still persist

    Treatment of Perichondritis with a Quinolone Derivativeā€”Norfloxacin

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    Auricular perichondritis is an uncommon complication following surgery of the external ear. Pseudomonas aeruginosa is the most commonly associated pathogen. Presented is a patient with auricular perichondritis successfully treated with norfloxacin, a newly available, orally administered antibiotic with antipseudomonal activity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74571/1/j.1524-4725.1988.tb03381.x.pd

    BamView: visualizing and interpretation of next-generation sequencing read alignments.

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    So-called next-generation sequencing (NGS) has provided the ability to sequence on a massive scale at low cost, enabling biologists to perform powerful experiments and gain insight into biological processes. BamView has been developed to visualize and analyse sequence reads from NGS platforms, which have been aligned to a reference sequence. It is a desktop application for browsing the aligned or mapped reads [Ruffalo, M, LaFramboise, T, KoyutĆ¼rk, M. Comparative analysis of algorithms for next-generation sequencing read alignment. Bioinformatics 2011;27:2790-6] at different levels of magnification, from nucleotide level, where the base qualities can be seen, to genome or chromosome level where overall coverage is shown. To enable in-depth investigation of NGS data, various views are provided that can be configured to highlight interesting aspects of the data. Multiple read alignment files can be overlaid to compare results from different experiments, and filters can be applied to facilitate the interpretation of the aligned reads. As well as being a standalone application it can be used as an integrated part of the Artemis genome browser, BamView allows the user to study NGS data in the context of the sequence and annotation of the reference genome. Single nucleotide polymorphism (SNP) density and candidate SNP sites can be highlighted and investigated, and read-pair information can be used to discover large structural insertions and deletions. The application will also calculate simple analyses of the read mapping, including reporting the read counts and reads per kilobase per million mapped reads (RPKM) for genes selected by the user

    Circlator: automated circularization of genome assemblies using long sequencing reads

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    The assembly of DNA sequence data is undergoing a renaissance thanks to emerging technologies capable of producing reads tens of kilobases long. Assembling complete bacterial and small eukaryotic genomes is now possible, but the final step of circularizing sequences remains unsolved. Here we present Circlator, the first tool to automate assembly circularization and produce accurate linear representations of circular sequences. Using Pacific Biosciences and Oxford Nanopore data, Circlator correctly circularized 26 of 27 circularizable sequences, comprising 11 chromosomes and 12 plasmids from bacteria, the apicoplast and mitochondrion of Plasmodium falciparum and a human mitochondrion. Circlator is available at http://sanger-pathogens.github.io/circlator/

    Children's learning of number words in an indigenous farming-foraging group

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    We show that children in the Tsimane', a farming-foraging group in the Bolivian rain-forest, learn number words along a similar developmental trajectory to children from industrialized countries. Tsimane' children successively acquire the first three or four number words before fully learning how counting works. However, their learning is substantially delayed relative to children from the United States, Russia, and Japan. The presence of a similar developmental trajectory likely indicates that the incremental stages of numerical knowledge ā€“ but not their timing ā€” reflect a fundamental property of number concept acquisition which is relatively independent of language, culture, age, and early education.National Science Foundation (U.S.) (NSF Award 1022684)National Institutes of Health (U.S.) (NIH Ruth L. Kirschstein National Research Service Award (NRSA)

    PrimPol is required for replicative tolerance of G quadruplexes in vertebrate cells

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    G quadruplexes (G4s) can present potent blocks to DNA replication. Accurate and timely replication of G4s in vertebrates requires multiple specialized DNA helicases and polymerases to prevent genetic and epigenetic instability. Here we report that PrimPol, a recently described primase-polymerase (PrimPol), plays a crucial role in the bypass of leading strand G4 structures. While PrimPol is unable to directly replicate G4s, it can bind and reprime downstream of these structures. Disruption of either the catalytic activity or zinc-finger of PrimPol results in extreme G4-dependent epigenetic instability at the BU-1 locus in avian DT40 cells, indicative of extensive uncoupling of the replicative helicase and polymerase. Together, these observations implicate PrimPol in promoting restart of DNA synthesis downstream of, but closely coupled to, G4 replication impediments

    Growth and age of the Antarctic bryozonan Cellaria incula on the Weddell Sea shelf

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    *tbrey~a~~z-bremerhaven de Abstract: We analysed growth of the arborescent Antarctic cheilostoine bryozoan Cellaria incula by stable carbon and oxygen isotope analysis. The growth of one complete branch of C. incula takes one year, i.e. owing to the bifurcate colony structure two new branches grow froin each branch of the previous generation, The maximum age of a C. incula colony is likely to be more than 14 years. Annual production-to-biomass ratio is 0.67, the highest value hitherto measured for any benthic invertebrate south of 62"s. Comparatively fast growth and high productivity identi @ C. zncula as a pioneer species which is able to quickly occupy spatial niches produced by iceberg scouring on the Antarctic shelf
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