2,605 research outputs found

    Evolución de la proteólisis durante la maduración de quesos Danbo elaborados con distintos cultivos iniciadores

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    La determinación de nitrógeno soluble a pH 4,6 (NNC), nitrógeno soluble en ácido tricloroacético (12 %) (NTCA) y nitrógeno soluble en ácido fosfotúngstico (5 %) (NPTA) se utiliza como índice de maduración de quesos, ya que proporciona información adecuada de la extensión global de la proteólisis. La formación de péptidos y aminoácidos durante la maduración del queso contribuye directamente al desarrollo del sabor y textura del queso, de allí la importancia de conocer si el uso de distintos cultivos iniciadores genera diferencias en el desarrollo de la proteólisis. En este trabajo se estudiaron los cambios proteolíticos durante la maduración de quesos Danbo elaborados con cultivos iniciadores que difieren en la proporción de sus microorganismos componentes: Lote A con: 60 % Streptococcus thermophilus subsp. thermophilus – 40 % (Lactococcus lactis subsp. lactis + Lactococcus lactis subsp. cremoris) y Lote B con: 50 % Streptococcus thermophilus subsp. thermophilus – 50 % (Lactococcus lactis subsp. lactis y Lactococcus lactis subsp. cremoris). Se analizaron quesos con 0, 15, 30 y 45 días de maduración y se determinó contenido de humedad, pH, contenido de nitrógeno en queso y contenido de nitrógeno de las distintas fracciones nitrogenadas. El lote elaborado con un mayor porcentaje de cultivo mesófilo (Lactococcus lactis subsp. lactis y Lactococcus lactis subsp. cremoris), lote B, fue el que presentó mayor proteólisis primaria y mayor formación de oligopéptidos y aminoácidos libres

    Calcitization of aragonitic bryozoans in Cenozoic tropical carbonates from East Kalimantan, Indonesia

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    © The Author(s) 2016. Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The file attached is the published version of the article

    In search of phylogenetic congruence between molecular and morphological data in bryozoans with extreme adult skeletal heteromorphy

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    peerreview_statement: The publishing and review policy for this title is described in its Aims & Scope. aims_and_scope_url: http://www.tandfonline.com/action/journalInformation?show=aimsScope&journalCode=tsab20© Crown Copyright 2015. This document is the author's final accepted/submitted version of the journal article. You are advised to consult the publisher's version if you wish to cite from it

    The origin of multicellularity in cyanobacteria

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    Background: Cyanobacteria are one of the oldest and morphologically most diverse prokaryotic phyla on our planet. The early development of an oxygen-containing atmosphere approximately 2.45 - 2.22 billion years ago is attributed to the photosynthetic activity of cyanobacteria. Furthermore, they are one of the few prokaryotic phyla where multicellularity has evolved. Understanding when and how multicellularity evolved in these ancient organisms would provide fundamental information on the early history of life and further our knowledge of complex life forms. Results: We conducted and compared phylogenetic analyses of 16S rDNA sequences from a large sample of taxa representing the morphological and genetic diversity of cyanobacteria. We reconstructed ancestral character states on 10,000 phylogenetic trees. The results suggest that the majority of extant cyanobacteria descend from multicellular ancestors. Reversals to unicellularity occurred at least 5 times. Multicellularity was established again at least once within a single-celled clade. Comparison to the fossil record supports an early origin of multicellularity, possibly as early as the “Great Oxygenation Event” that occurred 2.45 - 2.22 billion years ago. Conclusions: The results indicate that a multicellular morphotype evolved early in the cyanobacterial lineage and was regained at least once after a previous loss. Most of the morphological diversity exhibited in cyanobacteria today —including the majority of single-celled species— arose from ancient multicellular lineages. Multicellularity could have conferred a considerable advantage for exploring new niches and hence facilitated the diversification of new lineages

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

    A fresh look at the evolution and diversification of photochemical reaction centers

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    In this review, I reexamine the origin and diversification of photochemical reaction centers based on the known phylogenetic relations of the core subunits, and with the aid of sequence and structural alignments. I show, for example, that the protein folds at the C-terminus of the D1 and D2 subunits of Photosystem II, which are essential for the coordination of the water-oxidizing complex, were already in place in the most ancestral Type II reaction center subunit. I then evaluate the evolution of reaction centers in the context of the rise and expansion of the different groups of bacteria based on recent large-scale phylogenetic analyses. I find that the Heliobacteriaceae family of Firmicutes appears to be the earliest branching of the known groups of phototrophic bacteria; however, the origin of photochemical reaction centers and chlorophyll synthesis cannot be placed in this group. Moreover, it becomes evident that the Acidobacteria and the Proteobacteria shared a more recent common phototrophic ancestor, and this is also likely for the Chloroflexi and the Cyanobacteria. Finally, I argue that the discrepancies among the phylogenies of the reaction center proteins, chlorophyll synthesis enzymes, and the species tree of bacteria are best explained if both types of photochemical reaction centers evolved before the diversification of the known phyla of phototrophic bacteria. The primordial phototrophic ancestor must have had both Type I and Type II reaction centers

    Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector

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    A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13  TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV

    Search for direct stau production in events with two hadronic tau-leptons in root s=13 TeV pp collisions with the ATLAS detector

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    A search for the direct production of the supersymmetric partners ofτ-leptons (staus) in final stateswith two hadronically decayingτ-leptons is presented. The analysis uses a dataset of pp collisions corresponding to an integrated luminosity of139fb−1, recorded with the ATLAS detector at the LargeHadron Collider at a center-of-mass energy of 13 TeV. No significant deviation from the expected StandardModel background is observed. Limits are derived in scenarios of direct production of stau pairs with eachstau decaying into the stable lightest neutralino and oneτ-lepton in simplified models where the two staumass eigenstates are degenerate. Stau masses from 120 GeV to 390 GeV are excluded at 95% confidencelevel for a massless lightest neutralino

    Habitable Zones in the Universe

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    Habitability varies dramatically with location and time in the universe. This was recognized centuries ago, but it was only in the last few decades that astronomers began to systematize the study of habitability. The introduction of the concept of the habitable zone was key to progress in this area. The habitable zone concept was first applied to the space around a star, now called the Circumstellar Habitable Zone. Recently, other, vastly broader, habitable zones have been proposed. We review the historical development of the concept of habitable zones and the present state of the research. We also suggest ways to make progress on each of the habitable zones and to unify them into a single concept encompassing the entire universe.Comment: 71 pages, 3 figures, 1 table; to be published in Origins of Life and Evolution of Biospheres; table slightly revise

    Lung abscess predicts the surgical outcome in patients with pleural empyema

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    <p>Abstract</p> <p>Objectives</p> <p>Most cases of pleural empyema are caused by pulmonary infections, which are usually combined with pneumonia or lung abscess. The mortality of patients with pleural empyema remains high (up to 20%). It also contributes to higher hospital costs and longer hospital stays. We studied pleural empyema with combined lung abscess to determine if abscess was associated with mortality.</p> <p>Methods</p> <p>From January 2004 to December 2006, we retrospectively reviewed 259 patients diagnosed with pleural empyema who received thoracscopic decortications of the pleura in a single medical center. We evaluated their clinical data and analyzed their chest computed tomography scans. Outcomes of pleural empyema were compared between groups with and without lung abscess.</p> <p>Results</p> <p>Twenty-two pleural empyema patients had lung abscesses. Clinical data showed significantly higher incidences in the lung abscess group of pre-operative leukocytosis, need for an intensive care unit stay and mortality.</p> <p>Conclusion</p> <p>Patients with pleural empyema and lung abscess have higher intensive care unit admission rate, higher mortality during 30 days and overall mortality than patients with pleural empyema. The odds ratio of lung abscess is 4.685. Physician shall pay more attention on high risk patient of lung abscess for early detection and management.</p
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