402 research outputs found

    BAO+BBN revisited -- Growing the Hubble tension with a 0.7km/s/Mpc constraint

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    The combination of Baryonic Acoustic Oscillation (BAO) data together with light element abundance measurements from Big Bang Nucleosynthesis (BBN) has been shown to constrain the cosmological expansion history to an unprecedented degree. Using the newest LUNA data and DR16 data from SDSS, the BAO+BBN probe puts tight constraints on the Hubble parameter (H0=67.6±1.0km/s/MpcH_0 = 67.6 \pm 1.0 \mathrm{km/s/Mpc}), resulting in a 3.7σ3.7\sigma tension with the local distance ladder determination from SH0ES in a Λ\LambdaCDM model. In the updated BAO data the high- and low-redshift subsets are mutually in excellent agreement, and there is no longer a mild internal tension to artificially enhance the constraints. Adding the recently-developed ShapeFit analysis yields H0=68.3±0.7km/s/MpcH_0 = 68.3 \pm 0.7 \mathrm{km/s/Mpc} (3.8σ3.8 \sigma tension). For combinations with additional data sets, there is a strong synergy with the sound horizon information of the cosmic microwave background, which leads to one of the tightest constraints to date, H0=68.30±0.45km/s/MpcH_0 = 68.30\pm 0.45\mathrm{km/s/Mpc}, in 4.2σ4.2\sigma tension with SH0ES. The region preferred by this combination is perfectly in agreement with that preferred by ShapeFit. The addition of supernova data also yields a 4.2σ4.2\sigma tension with SH0ES for Pantheon, and a 3.5σ3.5\sigma tension for PantheonPLUS. Finally, we show that there is a degree of model-dependence of the BAO+BBN constraints with respect to early-time solutions of the Hubble tension, and the loss of constraining power in extended models depends on whether the model can be additionally constrained from BBN observations.Comment: 27 pages, 9 figures, 1 table. Comments are welcome

    Simulation of a finishing operation : milling of a turbine blade and influence of damping

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    Milling is used to create very complex geometries and thin parts, such as turbine blades. Irreversible geometric defects may appear during finishing operations when a high surface quality is expected. Relative vibrations between the tool and the workpiece must be as small as possible, while tool/workpiece interactions can be highly non-linear. A general virtual machining approach is presented and illustrated. It takes into account the relative motion and vibrations of the tool and the workpiece. Both deformations of the tool and the workpiece are taken into account. This allows predictive simulations in the time domain. As an example the effect of damping on the behavior during machining of one of the 56 blades of a turbine disk is analysed in order to illustrate the approach potential

    Vom Zwang zur Pockenschutzimpfung zum Nationalen Impfplan

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    Im Deutschen Reich wurden Pockenschutzimpfungen staatlich organisiert. Eine reichsweite Impfpflicht wurde 1874 eingefĂŒhrt, die in der Bundesrepublik Deutschland (BRD) und Deutschen Demokratischen Republik (DDR) bis 1982/1983 fortgefĂŒhrt wurde. ZustĂ€ndig fĂŒr Impfungen waren die 1935 gegrĂŒndeten GesundheitsĂ€mter. In der DDR wurde das Impfwesen straff organisiert: Man unternahm große Anstrengungen zur Erzielung hoher Impfquoten. Die diesbezĂŒglichen ZustĂ€ndigkeiten waren auf allen Ebenen und fĂŒr jedes Lebensalter klar definiert. WĂ€hrend es zunĂ€chst nur regionale Impfpflichten gab, enthielt der spĂ€tere Impfkalender in Form einer Rechtsvorschrift nationale Pflichtimpfungen beispielsweise gegen Masern. Auch in der BRD bestanden zunĂ€chst auf LĂ€nderebene vereinzelte Impfpflichten. Mit EinfĂŒhrung des Bundes-Seuchengesetzes 1961 setzte man auf freiwillige Impfungen basierend auf Impfempfehlungen. Seit den 1980er-Jahren verlagerte sich die DurchfĂŒhrung von Impfungen zunehmend vom öffentlichen Gesundheitsdienst (ÖGD) hin zu den niedergelassenen Ärzten. Inzwischen impft der ÖGD ĂŒberwiegend nur noch subsidiĂ€r und 2007 wurden Impfungen Pflichtleistungen der gesetzlichen Krankenkassen. Die LĂ€nder entwickelten unlĂ€ngst zur Förderung von Impfstrategien einen Nationalen Impfplan.In the German Reich, smallpox vaccinations were organized by the state. A mandatory vaccination throughout the empire was introduced in 1874, which was continued in the Federal Republic of Germany (FRG) and the German Democratic Republic (GDR) until 1982/1983. From 1935, health departments were responsible for vaccinations. In the GDR, immunization was tightly organized: The state made great efforts to achieve high vaccination rates. Responsibilities were clearly defined at all levels and for all ages. While vaccination was initially mandatory only at the regional level, the legally mandated immunization schedule later contained compulsory vaccinations, e.g., against measles. In the beginning there were mandatory vaccinations in the FRG at the LĂ€nder level. Since 1961, the Federal Epidemics Act has impeded obligatory vaccinations. Instead, voluntary vaccinations based on recommendations were stressed. Since the 1980s, vaccinations have been shifted from the public health service sector to office-based physicians. Today, public health authorities offer mainly supplementary vaccinations. In 2007, protective immunizations were introduced as compulsory benefits of the statutory health insurance (SHI). Recently, the German federal states developed a National Vaccination Plan to support immunization strategies

    Genomic basis for skin phenotype and cold adaptation in the extinct Steller’s sea cow

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    Steller’s sea cow, an extinct sirenian and one of the largest Quaternary mammals, was described by Georg Steller in 1741 and eradicated by humans within 27 years. Here, we complement Steller’s descriptions with paleogenomic data from 12 individuals. We identified convergent evolution between Steller’s sea cow and cetaceans but not extant sirenians, suggesting a role of several genes in adaptation to cold aquatic (or marine) environments. Among these are inactivations of lipoxygenase genes, which in humans and mouse models cause ichthyosis, a skin disease characterized by a thick, hyperkeratotic epidermis that recapitulates Steller’s sea cows’ reportedly bark-like skin. We also found that Steller’s sea cows’ abundance was continuously declining for tens of thousands of years before their description, implying that environmental changes also contributed to their extinction

    Lateral Distribution of Muons in IceCube Cosmic Ray Events

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    In cosmic ray air showers, the muon lateral separation from the center of the shower is a measure of the transverse momentum that the muon parent acquired in the cosmic ray interaction. IceCube has observed cosmic ray interactions that produce muons laterally separated by up to 400 m from the shower core, a factor of 6 larger distance than previous measurements. These muons originate in high pT (> 2 GeV/c) interactions from the incident cosmic ray, or high-energy secondary interactions. The separation distribution shows a transition to a power law at large values, indicating the presence of a hard pT component that can be described by perturbative quantum chromodynamics. However, the rates and the zenith angle distributions of these events are not well reproduced with the cosmic ray models tested here, even those that include charm interactions. This discrepancy may be explained by a larger fraction of kaons and charmed particles than is currently incorporated in the simulations

    Search for Relativistic Magnetic Monopoles with IceCube

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    We present the first results in the search for relativistic magnetic monopoles with the IceCube detector, a subsurface neutrino telescope located in the South Polar ice cap containing a volume of 1 km3^{3}. This analysis searches data taken on the partially completed detector during 2007 when roughly 0.2 km3^{3} of ice was instrumented. The lack of candidate events leads to an upper limit on the flux of relativistic magnetic monopoles of \Phi_{\mathrm{90%C.L.}}\sim 3\e{-18}\fluxunits for ÎČ≄0.8\beta\geq0.8. This is a factor of 4 improvement over the previous best experimental flux limits up to a Lorentz boost Îł\gamma below 10710^{7}. This result is then interpreted for a wide range of mass and kinetic energy values.Comment: 11 pages, 11 figures. v2 is minor text edits, no changes to resul

    Search for non-relativistic Magnetic Monopoles with IceCube

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    The IceCube Neutrino Observatory is a large Cherenkov detector instrumenting 1 km31\,\mathrm{km}^3 of Antarctic ice. The detector can be used to search for signatures of particle physics beyond the Standard Model. Here, we describe the search for non-relativistic, magnetic monopoles as remnants of the GUT (Grand Unified Theory) era shortly after the Big Bang. These monopoles may catalyze the decay of nucleons via the Rubakov-Callan effect with a cross section suggested to be in the range of 10−27 cm210^{-27}\,\mathrm{cm^2} to 10−21 cm210^{-21}\,\mathrm{cm^2}. In IceCube, the Cherenkov light from nucleon decays along the monopole trajectory would produce a characteristic hit pattern. This paper presents the results of an analysis of first data taken from May 2011 until May 2012 with a dedicated slow-particle trigger for DeepCore, a subdetector of IceCube. A second analysis provides better sensitivity for the brightest non-relativistic monopoles using data taken from May 2009 until May 2010. In both analyses no monopole signal was observed. For catalysis cross sections of 10−22 (10−24) cm210^{-22}\,(10^{-24})\,\mathrm{cm^2} the flux of non-relativistic GUT monopoles is constrained up to a level of Ί90≀10−18 (10−17) cm−2s−1sr−1\Phi_{90} \le 10^{-18}\,(10^{-17})\,\mathrm{cm^{-2}s^{-1}sr^{-1}} at a 90% confidence level, which is three orders of magnitude below the Parker bound. The limits assume a dominant decay of the proton into a positron and a neutral pion. These results improve the current best experimental limits by one to two orders of magnitude, for a wide range of assumed speeds and catalysis cross sections.Comment: 20 pages, 20 figure

    All-sky search for time-integrated neutrino emission from astrophysical sources with 7 years of IceCube data

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    Since the recent detection of an astrophysical flux of high energy neutrinos, the question of its origin has not yet fully been answered. Much of what is known about this flux comes from a small event sample of high neutrino purity, good energy resolution, but large angular uncertainties. In searches for point-like sources, on the other hand, the best performance is given by using large statistics and good angular reconstructions. Track-like muon events produced in neutrino interactions satisfy these requirements. We present here the results of searches for point-like sources with neutrinos using data acquired by the IceCube detector over seven years from 2008--2015. The discovery potential of the analysis in the northern sky is now significantly below EÎœ2dϕ/dEÎœ=10−12 TeV cm−2 s−1E_\nu^2d\phi/dE_\nu=10^{-12}\:\mathrm{TeV\,cm^{-2}\,s^{-1}}, on average 38%38\% lower than the sensitivity of the previously published analysis of four years exposure. No significant clustering of neutrinos above background expectation was observed, and implications for prominent neutrino source candidates are discussed.Comment: 19 pages, 17 figures, 3 tables; ; submitted to The Astrophysical Journa

    Neutrinos and Cosmic Rays Observed by IceCube

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    The core mission of the IceCube Neutrino observatory is to study the origin and propagation of cosmic rays. IceCube, with its surface component IceTop, observes multiple signatures to accomplish this mission. Most important are the astrophysical neutrinos that are produced in interactions of cosmic rays, close to their sources and in interstellar space. IceCube is the first instrument that measures the properties of this astrophysical neutrino flux, and constrains its origin. In addition, the spectrum, composition and anisotropy of the local cosmic-ray flux are obtained from measurements of atmospheric muons and showers. Here we provide an overview of recent findings from the analysis of IceCube data, and their implications on our understanding of cosmic rays.Comment: Review article, to appear in Advances in Space Research, special issue "Origins of Cosmic Rays
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