402 research outputs found
BAO+BBN revisited -- Growing the Hubble tension with a 0.7km/s/Mpc constraint
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 (), resulting in a tension with the local distance
ladder determination from SH0ES in a CDM 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 ( 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, , in
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 tension with SH0ES for Pantheon, and a
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
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
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 groĂe 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 (ĂGD) hin zu den niedergelassenen Ărzten. Inzwischen impft der ĂGD 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 Stellerâs sea cow
Stellerâs 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 Stellerâs descriptions with paleogenomic data from 12 individuals. We identified convergent evolution between Stellerâs 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 Stellerâs sea cowsâ reportedly bark-like skin. We also found that Stellerâs sea cowsâ 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
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
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 km. This analysis
searches data taken on the partially completed detector during 2007 when
roughly 0.2 km 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 . This is a
factor of 4 improvement over the previous best experimental flux limits up to a
Lorentz boost below . 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
The IceCube Neutrino Observatory is a large Cherenkov detector instrumenting
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 to
. 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 the flux of non-relativistic
GUT monopoles is constrained up to a level of 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
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 , on average
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
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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