1,015 research outputs found

    Hydrogen Utilization Potential in Subsurface Sediments

    Get PDF
    Subsurface microbial communities undertake many terminal electron-accepting processes, often simultaneously. Using a tritium-based assay, we measured the potential hydrogen oxidation catalyzed by hydrogenase enzymes in several subsurface sedimentary environments (Lake Van, Barents Sea, Equatorial Pacific, and Gulf of Mexico) with different predominant electron-acceptors. Hydrogenases constitute a diverse family of enzymes expressed by microorganisms that utilize molecular hydrogen as a metabolic substrate, product, or intermediate. The assay reveals the potential for utilizing molecular hydrogen and allows qualitative detection of microbial activity irrespective of the predominant electron-accepting process. Because the method only requires samples frozen immediately after recovery, the assay can be used for identifying microbial activity in subsurface ecosystems without the need to preserve live material. We measured potential hydrogen oxidation rates in all samples from multiple depths at several sites that collectively span a wide range of environmental conditions and biogeochemical zones. Potential activity normalized to total cell abundance ranges over five orders of magnitude and varies, dependent upon the predominant terminal electron acceptor. Lowest per-cell potential rates characterize the zone of nitrate reduction and highest per-cell potential rates occur in the methanogenic zone. Possible reasons for this relationship to predominant electron acceptor include (i) increasing importance of fermentation in successively deeper biogeochemical zones and (ii) adaptation of H2ases to successively higher concentrations of H2 in successively deeper zones

    dolls/puppets in threat scenarios

    Get PDF
    Puppen in Bedrohungsszenarien – so lautet der Themenschwerpunkt der ersten Ausgabe der interdisziplinĂ€ren online-Zeitschrift "denkste: puppe / just a bit of: doll" zu Mensch-Puppen-Diskursen (Akronym: de:do). Die Bezeichnung ‚Puppe’ steht dabei fĂŒr anthropomorphe ,Wesen’ und Artefakte in all ihren unterschiedlichen Erscheinungsformen und der Begriff der Bedrohung wird hier weit gefasst. Ausgangspunkt der Entscheidung fĂŒr diesen Fokus war die Annahme, dass Puppen und puppenaffinen Artefakten sowohl in Zeiten existenzieller Bedrohung als auch in Phasen innerpsychischer Beunruhigung und Irritation eine besondere Bedeutung zukommt. Die hier einbezogenen BeitrĂ€ge stammen aus unterschiedlichen Fachdisziplinen und eröffnen in der bewusst nicht disziplinĂ€r ausgerichteten Zusammenstellung reizvolle multiperspektivische Mensch-Puppen-Diskurse. Dabei sind nicht nur die hier angesprochenen ThemenbezĂŒge, sondern auch die jeweiligen methodischen ZugĂ€nge ausgesprochen heterogen. So werden Puppen-Narrative aufgegriffen, die beispielsweise innerhalb der Literaturwissenschaft an die lange Tradition von Puppen-ErzĂ€hlungen anknĂŒpfen, aber auch solche, die aktuell in den Diskursen ĂŒber Zukunftsszenarien und neue Technologien mittels verschiedener medialer Formate und/oder kĂŒnstlerischer Aktionen fĂŒr Diskussionsstoff sorgen. Ein erster thematischer Fokus liegt auf der Bedeutung von Puppen im Zuge der Erfahrung von Bedrohung und Verlusten im Kontext von Krieg, Flucht und Verfolgung in politisch unsicheren Zeiten. Hier werden aus verschiedenen fachdisziplinĂ€ren Perspektiven unterschiedliche Facetten von Bedrohungsszenarien angesprochen. So geht es aus theaterwissenschaftlicher Sicht um zwei Inszenierungen aus dem Bereich des Objekt- und Materialtheaters, in denen bedrohliche Kriegsdarstellungen mittels Plastikpuppen bzw. amorphen Materials aufbereitet werden. Aus psychologischer Perspektive kommen Rollen und Funktionen von Puppen als Übergangsobjekte im Kontext von UmbrĂŒchen, Krieg und Gewalt zur Sprache. In zwei literaturwissenschaftlichen BeitrĂ€gen wird jeweils ein Roman aus der Kinder- und Jugendliteratur analysiert, in denen in einem Fall eine Puppe zur psychischen Stabilisierung der literarischen Protagonistin beitrĂ€gt und im anderen Fall das Schicksal der Puppe die Geschichte von Abschied und letztendlicher Vernichtung ihrer Besitzerin erzĂ€hlt und symbolisiert. Und schließlich geht es um den Stellenwert von Puppen und Teddys in verschiedenen Kinderzeitschriften, die – in den politisch unsicheren Zeiten zwischen und nach den beiden Weltkriegen – Identifikationsfiguren und Interaktionspartner fĂŒr Kinder sein können. Ein zweiter Fokus thematisiert Puppen und ihre Narrative im Kontext verschiedener aversiver Erfahrungen sowie in Zeiten psychischer Irritation. So geht es zum einen um die literaturwissenschaftliche Sicht auf die Bedeutung und Wirkung von Puppen in zwei ‚klassischen’ PuppenerzĂ€hlungen: „"Nussknacker und Mausekönig" von E.T.A. Hoffmann und "Romeo und Julia auf dem Dorfe" von Gottfried Keller. Zum anderen werden in verschiedenen BeitrĂ€gen Entgrenzungs-, Transformations- und IdentitĂ€tsfragen in Mensch-Puppen-BezĂŒgen aus medien- und kunstwissenschaftlicher sowie kinderliterarischer Perspektive angesprochen, in denen Puppen in Gestalt von Androiden, Kunstwesen oder anthropomorphen Figuren agieren und dabei selber Irritationen auslösen oder Versuche darstellen, Antworten auf beunruhigende Fragen zu finden. Über den Themenschwerpunkt hinaus finden sich zudem eine Reihe weiterer Beitragsformen zu verschiedenen puppenbezogenen Themen und Praxen, die noch einmal das breite Spektrum unterschiedlicher Puppen-Narrative und Zugangsformen dokumentieren: So beschĂ€ftigt sich ein freier Beitrag mit dem Puppenspiel als strukturiertes Therapieangebot fĂŒr Kinder, bei den Miszellen findet sich eine Skizze zu Marlene Dietrich und ihren Puppen sowie ein kurzer Essay zu einer biographischen Erinnerung, ein Interview mit der BegrĂŒnderin des Berliner Puppentheaters bubales veranschaulicht Möglichkeiten der dramatischen und poetischen Umsetzung von Puppen-Themen, im Diskussionsforum wird ein kritischer Blick auf "Barbie als Diskursmaschine" geworfen und eine Rezension zum Ausstellungskatalog "From Her Wooden Sleep von Ydessa Hendels" lotet Chancen und Grenzen der kĂŒnstlerischen Arbeit mit Puppen-Artefakten aus.Dolls / Puppets in Threat Scenarios – this is the topic focus of the first issue of the interdisciplinary online magazine "denkste: puppe / just a bit of: doll" on human-doll discourses (acronym: de: do). The term ’doll’ stands for anthropomorphic ’beings’ and artifacts of all kinds and the concept of threat is broadly defined. This focus was stimulated by the assumption that dolls and doll-related artifacts are of particular importance in times of existential threat as well as in phases of inner psychic anxiety and irritation. Yet, the basically ambiguous character of the doll does not necessarily determine a clear effect, so that its usability always involves a certain blurriness and ambivalence. In threatening and adverse situations dolls can act as companions and significant (transitional) objects, thus allowing psychic stabilization, security, and attachment as well as enabling (inner) autonomy, agency, and developmental processes. But dolls can also be a crucial component of threat scenarios themselves and act frightening in this function. All this applies not only to material and real existing dolls and puppets, but also to dolls as literary and / or media figures as well as to doll narratives of any kind. The articles included here come from different disciplines and open up an appealing and deliberately non-disciplinary oriented human-doll discourse from multiple perspectives. Accordingly, the relevant themes as well as the respective methodological approaches are highly heterogeneous. Thus, some contributions follow the long tradition of doll narratives in literature while others discuss currrent topics and discourses on future scenarios and new technologies by means of various doll-related media formats and / or art performances. A first thematic focus is on the significance of dolls in experiencing threats and losses in the context of war, flight and persecution in times of political uncertainty. Here, different facets of threat scenarios are addressed from different disciplinary perspectives. From the field of object and material theater two productions are introduced in which menacing war scenes are processed by means of plastic dolls or amorphous material. From a psychological perspective, dolls are discussed in their roles and functions as transitional objects within the context of upheaval, war and violence. Furthermore, two literary contributions analyze novels from children’s and youth literature. One story deals with a doll which contributes to the psychological stabilization of the literary protagonist. The other story tells of a girl and her doll which symbolizes the final farewell and eventual annihilation of the (Jewish) girl. Finally, the role of dolls and teddy bears in various children’s magazines is exemplified, which serve as identification figures and interaction partners for children in the politically unstable times between and after the two World Wars. A second focus deals with dolls and their narratives in the context of various aversive experiences as well as in times of psychological irritation. Two contributions analyze the meaning and effect of dolls in two ’classical’ doll narratives from a literary perspective: "Nussknacker und Mausekönig" by E.T.A. Hoffmann and "Romeo und Julia auf dem Dorfe" by Gottfried Keller. Further contributions address questions of ego dissolution, transformation and identity processes in human-doll relations from various perspectives such as media, art and children’s literature. Here, dolls appear as androids, artistic or anthropomorphic figures which cause irritation themselves or attempt to find answers to disturbing human-doll questions. In addition to the main topic, there are also a number of other sections and types of contributions on various doll-related topics and practices which once again document the wide range of doll narratives and possible forms of access: For example, a free contribution deals with doll play as a structured therapy for children, the miscellaneous section includes a portrait of Marlene Dietrich and her dolls as well as a short essay on a biographical reminiscence, an interview with the founder of the Berlin Puppet Theater bubales illustrates the possibilities of dramatic and poetic realization of puppet and doll narratives, a critical view on "Barbie as a discourse machine" is presented in the discussion forum and a review of the exhibition catalog "From Her Wooden Sleep by Ydessa Hendels" explores opportunities and limits of artistic work with doll artifacts

    Mutations in GDF5 Reveal a Key Residue Mediating BMP Inhibition by NOGGIN

    Get PDF
    Signaling output of bone morphogenetic proteins (BMPs) is determined by two sets of opposing interactions, one with heterotetrameric complexes of cell surface receptors, the other with secreted antagonists that act as ligand traps. We identified two mutations (N445K,T) in patients with multiple synostosis syndrome (SYM1) in the BMP–related ligand GDF5. Functional studies of both mutants in chicken micromass culture demonstrated a gain of function caused by a resistance to the BMP–inhibitor NOGGIN and an altered signaling effect. Residue N445, situated within overlapping receptor and antagonist interfaces, is highly conserved among the BMP family with the exception of BMP9 and BMP10, in which it is substituted with lysine. Like the mutant GDF5, both BMPs are insensitive to NOGGIN and show a high chondrogenic activity. Ectopic expression of BMP9 or the GDF5 mutants resulted in massive induction of cartilage in an in vivo chick model presumably by bypassing the feedback inhibition imposed by endogenous NOGGIN. Swapping residues at the mutation site alone was not sufficient to render Bmp9 NOG-sensitive; however, successive introduction of two additional substitutions imparted high to total sensitivity on customized variants of Bmp9. In conclusion, we show a new mechanism for abnormal joint development that interferes with a naturally occurring regulatory mechanism of BMP signaling

    Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

    Get PDF
    A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

    Combined searches for the production of supersymmetric top quark partners in proton-proton collisions at root s=13 TeV

    Get PDF
    A combination of searches for top squark pair production using proton-proton collision data at a center-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 137 fb(-1) collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented. Depending on themodel, the combined result excludes a top squarkmass up to 1325 GeV for amassless neutralino, and a neutralinomass up to 700 GeV for a top squarkmass of 1150 GeV. Top squarks with masses from 145 to 295 GeV, for neutralino masses from 0 to 100 GeV, with a mass difference between the top squark and the neutralino in a window of 30 GeV around the mass of the top quark, are excluded for the first time with CMS data. The results of theses searches are also interpreted in an alternative signal model of dark matter production via a spin-0 mediator in association with a top quark pair. Upper limits are set on the cross section for mediator particle masses of up to 420 GeV

    Probing effective field theory operators in the associated production of top quarks with a Z boson in multilepton final states at root s=13 TeV

    Get PDF
    Peer reviewe

    Measurement of the top quark mass using events with a single reconstructed top quark in pp collisions at root s=13 TeV

    Get PDF
    Abstract:A measurement of the top quark mass is performed using a data sample en-riched with single top quark events produced in thetchannel. The study is based on proton-proton collision data, corresponding to an integrated luminosity of 35.9 fb−1, recorded at√s= 13TeV by the CMS experiment at the LHC in 2016. Candidate events are selectedby requiring an isolated high-momentum lepton (muon or electron) and exactly two jets,of which one is identified as originating from a bottom quark. Multivariate discriminantsare designed to separate the signal from the background. Optimized thresholds are placedon the discriminant outputs to obtain an event sample with high signal purity. The topquark mass is found to be172.13+0.76−0.77GeV, where the uncertainty includes both the sta-tistical and systematic components, reaching sub-GeV precision for the first time in thisevent topology. The masses of the top quark and antiquark are also determined separatelyusing the lepton charge in the final state, from which the mass ratio and difference aredetermined to be0.9952+0.0079−0.0104and0.83+1.79−1.35GeV, respectively. The results are consistentwithCPTinvariance

    Observation of tW production in the single-lepton channel in pp collisions at root s=13 TeV

    Get PDF
    A measurement of the cross section of the associated production of a single top quark and a W boson in final states with a muon or electron and jets in proton-proton collisions at root s = 13 TeV is presented. The data correspond to an integrated luminosity of 36 fb(-1) collected with the CMS detector at the CERN LHC in 2016. A boosted decision tree is used to separate the tW signal from the dominant t (t) over bar background, whilst the subleading W+jets and multijet backgrounds are constrained using data-based estimates. This result is the first observation of the tW process in final states containing a muon or electron and jets, with a significance exceeding 5 standard deviations. The cross section is determined to be 89 +/- 4 (stat) +/- 12 (syst) pb, consistent with the standard model.Peer reviewe

    Search for a heavy Higgs boson decaying into two lighter Higgs bosons in the tau tau bb final state at 13 TeV

    Get PDF
    A search for a heavy Higgs boson H decaying into the observed Higgs boson h with a mass of 125 GeV and another Higgs boson h(S) is presented. The h and h(S) bosons are required to decay into a pair of tau leptons and a pair of b quarks, respectively. The search uses a sample of proton-proton collisions collected with the CMS detector at a center-of-mass energy of 13TeV, corresponding to an integrated luminosity of 137 fb(-1). Mass ranges of 240-3000 GeV for m(H) and 60-2800 GeV for m(hS) are explored in the search. No signal has been observed. Model independent 95% confidence level upper limits on the product of the production cross section and the branching fractions of the signal process are set with a sensitivity ranging from 125 fb (for m(H) = 240 GeV) to 2.7 fb (for m(H) = 1000 GeV). These limits are compared to maximally allowed products of the production cross section and the branching fractions of the signal process in the next-to-minimal supersymmetric extension of the standard model.Peer reviewe

    Measurements of the Electroweak Diboson Production Cross Sections in Proton-Proton Collisions at root s=5.02 TeV Using Leptonic Decays

    Get PDF
    The first measurements of diboson production cross sections in proton-proton interactions at a center-of-mass energy of 5.02 TeV are reported. They are based on data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 302 pb(-1). Events with two, three, or four charged light leptons (electrons or muons) in the final state are analyzed. The WW, WZ, and ZZ total cross sections are measured as sigma(WW) = 37:0(-5.2)(+5.5) (stat)(-2.6)(+2.7) (syst) pb, sigma(WZ) = 6.4(-2.1)(+2.5) (stat)(-0.3)(+0.5)(syst) pb, and sigma(ZZ) = 5.3(-2.1)(+2.5)(stat)(-0.4)(+0.5) (syst) pb. All measurements are in good agreement with theoretical calculations at combined next-to-next-to-leading order quantum chromodynamics and next-to-leading order electroweak accuracy
    • 

    corecore