1,985 research outputs found

    Fast recognition of alternating groups of unknown degree

    Full text link
    We present a constructive recognition algorithm to decide whether a given black-box group is isomorphic to an alternating or a symmetric group without prior knowledge of the degree. This eliminates the major gap in known algorithms, as they require the degree as additional input. Our methods are probabilistic and rely on results about proportions of elements with certain properties in alternating and symmetric groups. These results are of independent interest; for instance, we establish a lower bound for the proportion of involutions with small support.Comment: 31 pages, submitted to Journal of Algebr

    Lavender oil-potent anxiolytic properties via modulating voltage dependent calcium channels

    Get PDF
    Recent clinical data support the clinical use of oral lavender oil in patients suffering from subsyndromal anxiety. We identified the molecular mechanism of action that will alter the perception of lavender oil as a nonspecific ingredient of aromatherapy to a potent anxiolytic inhibiting voltage dependent calcium channels (VOCCs) as highly selective drug target. In contrast to previous publications where exorbitant high concentrations were used, the effects of lavender oil in behavioral, biochemical, and electrophysiological experiments were investigated in physiological concentrations in the nanomolar range, which correlate to a single dosage of 80 mg/d in humans that was used in clinical trials. We show for the first time that lavender oil bears some similarities with the established anxiolytic pregabalin. Lavender oil inhibits VOCCs in synaptosomes, primary hippocampal neurons and stably overexpressing cell lines in the same range such as pregabalin. Interestingly, Silexan does not primarily bind to P/Q type calcium channels such as pregabalin and does not interact with the binding site of pregabalin, the α2δ subunit of VOCCs. Lavender oil reduces non-selectively the calcium influx through several different types of VOCCs such as the N-type, P/Q-type and T-type VOCCs. In the hippocampus, one brain region important for anxiety disorders, we show that inhibition by lavender oil is mainly mediated via N-type and P/Q-type VOCCs. Taken together, we provide a pharmacological and molecular rationale for the clinical use of the oral application of lavender oil in patients suffering from anxiety

    Mitochondriale Dysfunktion bei Alzheimer-Demenz : das Zusammenspiel von Hirnalterung und genetischen Risikofaktoren

    Get PDF
    Typische neuropathologische Befunde bei der Alzheimer-Demenz (AD) sind die Bildung von Beta-Amyloid-Plaques, die Akkumulation von intrazellulären neurofibrillären Bündeln (Tangles) und ein ausgeprägter Verlust der Nervenzellen im Gehirn (siehe Estifanos Ghebremedhin und Thomas Deller »Risikofaktoren der Alzheimer-Krankheit. Was verraten uns die Gene?«, Seite 90). Insbesondere die Anhäufung von Beta-Amyloid-Peptid (Aß) scheint eine zentrale Rolle in der in der in der Pathogenese zu spielen und kausal für den Zelluntergang verantwortlich zu sein. Befunde unserer Arbeitsgruppe deuten darauf hin, das Aß zu mitochondrialer Dysfunktion in den Nervenzellen führt. Wir untersuchen die Kaskade der Mechanismen, die von der Bildung von Aß über mitochondriale Dysfunktion letztlich zu Synapsenverlust und Zelltod führen, mithilfe von Zelllinien und Mäusestämmen mit Alzheimer-typischen Merkmalen. Ziel ist, einen Angriffspunkt für die medikamentöse Behandlung der Alzheimer-Demenz zu finden. Als vielversprechend hat sich die Wirkung von Statinen erwiesen, die als Cholesterinhemmer eingesetzt werden. ..

    Medicinal potential, utilization and domestication status of bitter kola (Garcinia kola Heckel) in West and Central Africa

    Get PDF
    Garcinia kola Heckel (Clusiaceae), known as bitter kola, is a multipurpose tree indigenous to West and Central Africa. This highly preferred species is called wonder plant because all of its parts can be used as medicine. Its seeds, the most valued product of the tree, are commonly eaten to prevent/cure gastric disorders and for their typical astringent taste. There is a vast evidence that bioactive components of the seeds can serve as alternative medicine to treat/prevent severe illnesses such as malaria, hepatitis and immune-destructive diseases. Despite the species' pharmaceutical potential and its high preference by West and Central African communities, G. kola is still at the beginning of its domestication process. Even though, there are numerous scientific articles published on species biological activities, it is a difficult task to find basic information on its diversity, distribution, genetics, silvicultural management or botany. Therefore, in this very first review published on G. kola, we summarize all relevant information known about the species, target some of the challenges connected with its cultivation and propose a leading direction for future research and domestication process

    Engineering organizational change to ramp up research culture in schools of nursing

    Get PDF
    Session presented on: Thursday, July 25, 2013: Purpose: Changing an organization\u27s culture is challenging and requires comprehensive assessment and purposefully deploying organizational tools. This paper will present a model of engaging a process to ramp up a research culture in a College of Nursing where teaching was heretofore the primary focus. Methods: To purposefully engage in transformational change, an organizational consultant was utilized to conduct a systematic assessment of the college\u27s work culture and climate. The consultant used a case study approach to collect interview data from key individuals and teams, observe meetings of standing committees, and examine external forces and college documents such as the strategic plan. The core leadership team (e.g., Dean and Associate Deans) analyzed the consultant\u27s report to identify the college\u27s strengths and target areas that required change. Results: The process of changing the college\u27s culture included communicating leadership messages about culture change as well as using management tools and persuasion to reinforce and reward new expectations. The process of conducting a systematic case study and subsequent actions resulting from the case study effectively communicated the leadership message. Management tools and persuasion included a new structure for enhancing shared faculty governance, additional resources to support scholarship, and incentives and policies to reinforce new expectations. Faculty members willingly embraced the new expectation and the increase in scholarship activities was readily apparent. Conclusion: Successfully changing a culture to ramp up research requires engaging organizational tools at three levels - leadership, management, and persuasion. Leadership must seize the moment to swiftly and forcefully reinforce messages about new expectations for research. Management practices need to systematically drive the vision and reward research and scholarship activities. Persuasion requires being responsive to faculty concerns and realities and providing them with the resources to meet new expectations

    The contribution of Fermi-2LAC blazars to the diffuse TeV-PeV neutrino flux

    Get PDF
    The recent discovery of a diffuse cosmic neutrino flux extending up to PeV energies raises the question of which astrophysical sources generate this signal. One class of extragalactic sources which may produce such high-energy neutrinos are blazars. We present a likelihood analysis searching for cumulative neutrino emission from blazars in the 2nd Fermi-LAT AGN catalogue (2LAC) using an IceCube neutrino dataset 2009-12 which was optimised for the detection of individual sources. In contrast to previous searches with IceCube, the populations investigated contain up to hundreds of sources, the largest one being the entire blazar sample in the 2LAC catalogue. No significant excess is observed and upper limits for the cumulative flux from these populations are obtained. These constrain the maximum contribution of the 2LAC blazars to the observed astrophysical neutrino flux to be 27%27 \% or less between around 10 TeV and 2 PeV, assuming equipartition of flavours at Earth and a single power-law spectrum with a spectral index of 2.5-2.5. We can still exclude that the 2LAC blazars (and sub-populations) emit more than 50%50 \% of the observed neutrinos up to a spectral index as hard as 2.2-2.2 in the same energy range. Our result takes into account that the neutrino source count distribution is unknown, and it does not assume strict proportionality of the neutrino flux to the measured 2LAC γ\gamma-ray signal for each source. Additionally, we constrain recent models for neutrino emission by blazars.Comment: 18 pages, 22 figure

    Improved limits on dark matter annihilation in the Sun with the 79-string IceCube detector and implications for supersymmetry

    Get PDF
    We present an improved event-level likelihood formalism for including neutrino telescope data in global fits to new physics. We derive limits on spin-dependent dark matter-proton scattering by employing the new formalism in a re-analysis of data from the 79-string IceCube search for dark matter annihilation in the Sun, including explicit energy information for each event. The new analysis excludes a number of models in the weak-scale minimal supersymmetric standard model (MSSM) for the first time. This work is accompanied by the public release of the 79-string IceCube data, as well as an associated computer code for applying the new likelihood to arbitrary dark matter models.Comment: 24 pages, 8 figs, 1 table. Contact authors: Pat Scott & Matthias Danninger. Likelihood tool available at http://nulike.hepforge.org. v2: small updates to address JCAP referee repor
    corecore