858 research outputs found
Schwingungseigenschaften der Ossikel und der Cochlea und deren Bedeutung fĂŒr unser Gehör
Zusammenfassung: Untersuchungen der Bewegungen von Trommelfell und SteigbĂŒgel belegen, dass in den höheren Frequenzen komplexe, rĂ€umliche Vibrationsmuster auftreten, bei denen sich die einzelnen Elemente in sehr unterschiedlichen rĂ€umlichen Richtungen und in sehr unterschiedlichen Phasenlagen bewegen. Am SteigbĂŒgel sind eine kolbenförmige Bewegung sowie eine Rotation um die kurze und lange SteigbĂŒgelachse zu unterscheiden. Im Gegensatz zu den kolbenförmigen Schwingungen fĂŒhren Rotationsbewegungen nicht zu einer Nettovolumenverschiebung der cochleĂ€ren FlĂŒssigkeit in einem gewissen Abstand von der FuĂplatte. Deshalb wird aufgrund der gĂ€ngigen Theorie des Hörens angenommen, dass solche Kippbewegungen keinen Einfluss auf das Gehör haben. In einer Reihe von Studien wurde jedoch qualitativ gezeigt, dass auch Kippbewegungen zu cochleĂ€rer AktivitĂ€t fĂŒhren können. Weitere Forschung ist notwendig, um diesen Effekt zu quantifiziere
Aberrierende A.carotis interna als Ursache eines pulssynchronen Tinnitus: Schwierige Diagnose in der MRT?
Zusammenfassung: Wir prĂ€sentieren einen Fall eines 43 jĂ€hrigen Patienten mit einseitiger sensorineuraler Schwerhörigkeit und Zufallsbefund einer aberrierende A.carotis interna im linken Mittelohr, welche einen pulsierenden Tinnitus verursacht. Das aberrierende GefÀà war inital bei einer Magnetresonanztomographie (MRT) nicht zu sehen und konnte erst mittels Computertomographie und MR-Angiographie (MRA) nachgewiesen werden. Um den aberrierenden Verlauf einer A.carotis interna zu erkennen, ist hĂ€ufig neben einer konventionellen MRT eine MRA nötig, um die Diagnose zu sichern und andere Differenzialdiagnosen auszuschlieĂe
Following Gluonic World Lines to Find the QCD Coupling in the Infrared
Using a parametrization of the Wilson loop with the minimal-area law, we
calculate the polarization operator of a valence gluon, which propagates in the
confining background. This enables us to obtain the infrared freezing (i.e.
finiteness) of the running strong coupling in the confinement phase, as well as
in the deconfinement phase up to the temperature of dimensional reduction. The
momentum scale defining the onset of freezing is found both analytically and
numerically. The nonperturbative contribution to the thrust variable,
originating from the freezing, makes the value of this variable closer to the
experimental one.Comment: 25 pages, 5 figure
High-resolution UV spectrum of the benzeneâN2 van der Waals complex
The rotationally resolved spectrum of the 610 band of the S1 â S0 electronic transition of the benzeneâN2 van der Waals complex has been recorded and 119 transitions assigned. The C6H6·N2 complex, produced in a pulsed molecular beam, was detected by mass-selected two-photon two-colour ionization employing a high-resolution (ÎÎœUV = 100 MHz, fwhm) pulsed-amplified cw laser for the resonant intermediate excitation. The observed rotational structure is that of a rigid symmetric top with weaker additional rotational transitions most likely arising from the free internal rotation of the N2 in the plane parallel to the benzene ring. The N2 is located parallel to the benzene ring at a distance of 3.50 Ă
; this decreases by 45 mĂ
in the excited electronic state
The Quest for Antiinflammatory and Immunomodulatory Strategies in Heart Failure
Intensive research over the last 3 decades has unequivocally demonstrated the relevance of inflammation in heart failure (HF). Despite our current and ever increasing knowledge about inflammation, the clinical success of antiinflammatory and immunomodulatory therapies in HF is still limited. This review outlines the complexity and diversity of inflammation, its reciprocal interaction with HF, and addresses future perspectives, calling for immunomodulatory therapies that are specific for factors that activate the immune system without the risk of nonspecific immune suppression
The terroir of the finch: How spatial and temporal variation shapes phenotypic traits in Darwin\u27s finches
The term terroir is used in viticulture to emphasize how the biotic and abiotic characteristics of a local site influence grape physiology and thus the properties of wine. In ecology and evolution, such terroir (i.e., the effect of space or âsiteâ) is expected to play an important role in shaping phenotypic traits. Just how important is the pure spatial effect of terroir (e.g., differences between sites that persist across years) in comparison to temporal variation (e.g., differences between years that persist across sites), and the interaction between space and time (e.g., differences between sites change across years)? We answer this question by analyzing beak and body traits of 4388 medium ground finches (Geospiza fortis) collected across 10 years at three locations in GalĂĄpagos. Analyses of variance indicated that phenotypic variation was mostly explained by site for beak size (η2 = 0.42) and body size (η2 = 0.43), with a smaller contribution for beak shape (η2 = 0.05) and body shape (η2 = 0.12), but still higher compared to year and site-by-year effects. As such, the effect of terroir seems to be very strong in Darwin\u27s finches, notwithstanding the oft-emphasized interannual variation. However, these results changed dramatically when we excluded data from Daphne Major, indicating that the strong effect of terroir was mostly driven by that particular population. These phenotypic results were largely paralleled in analyses of environmental variables (rainfall and vegetation indices) expected to shape terroir in this system. These findings affirm the evolutionary importance of terroir, while also revealing its dependence on other factors, such as geographical isolation
Non-standard interactions using the OPERA experiment
We investigate the implications of non-standard interactions on neutrino
oscillations in the OPERA experiment. In particular, we study the non-standard
interaction parameter . We show that the OPERA experiment
has a unique opportunity to reduce the allowed region for this parameter
compared with other experiments such as the MINOS experiment, mostly due to the
higher neutrino energies in the CNGS beam compared to the NuMI beam. We find
that OPERA is mainly sensitive to a combination of standard and non-standard
parameters and that a resulting anti-resonance effect could suppress the
expected number of events. Furthermore, we show that running OPERA for five
years each with neutrinos and anti-neutrinos would help in resolving the
degeneracy between the standard parameters and . This
scenario is significantly better than the scenario with a simple doubling of
the statistics by running with neutrinos for ten years.Comment: 15 pages, 5 figures, REVTeX
The role of matter density uncertainties in the analysis of future neutrino factory experiments
Matter density uncertainties can affect the measurements of the neutrino
oscillation parameters at future neutrino factory experiments, such as the
measurements of the mixing parameters and \deltacp. We compare
different matter density uncertainty models and discuss the possibility to
include the matter density uncertainties in a complete statistical analysis.
Furthermore, we systematically study in which measurements and where in the
parameter space matter density uncertainties are most relevant. We illustrate
this discussion with examples that show the effects as functions of different
magnitudes of the matter density uncertainties. We find that matter density
uncertainties are especially relevant for large \stheta \gtrsim 10^{-3}.
Within the KamLAND-allowed range, they are most relevant for the precision
measurements of \stheta and \deltacp, but less relevant for ``binary''
measurements, such as for the sign of \ldm, the sensitivity to \stheta, or
the sensitivity to maximal CP violation. In addition, we demonstrate that
knowing the matter density along a specific baseline better than to about 1%
precision means that all measurements will become almost independent of the
matter density uncertainties.Comment: 21 pages, 7 figures, LaTeX. Final version to be published in Phys.
Rev.
Effects of new physics in neutrino oscillations in matter
A new flavor changing electron neutrino interaction with matter would always
dominate the nu_e oscillation probability at sufficiently high neutrino
energies. Being suppressed by theta_{13}, the energy scale at which the new
effect starts to be relevant may be within the reach of realistic experiments,
where the peculiar dependence of the signal with energy could give rise to a
clear signature in the nu_e --> nu_tau channel. The latter could be observed by
means of a coarse large magnetized detector by exploiting tau --> mu decays. We
discuss the possibility of identifying or constraining such effects with a high
energy neutrino factory. We also comment on the model independent limits on
them.Comment: 11 pages, 5 figure
Momentum-Resolved Tunneling into Fractional Quantum Hall Edges
Tunneling from a two-dimensional contact into quantum-Hall edges is
considered theoretically for a case where the barrier is extended, uniform, and
parallel to the edge. In contrast to previously realized tunneling geometries,
details of the microscopic edge structure are exhibited directly in the voltage
and magnetic-field dependence of the differential tunneling conductance. In
particular, it is possible to measure the dispersion of the edge-magnetoplasmon
mode, and the existence of additional, sometimes counterpropagating,
edge-excitation branches could be detected.Comment: 4 pages, 3 figures, RevTex
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