2,656 research outputs found
Semileptonic tau decays, structure functions, kinematics and polarisation
The most general angular distribution of two or three meson final states from
semileptonic decays , , ,
, , , of polarized
leptons can be characterized by 16 structure functions. Predictions for
hadronic matrix elements, based on CVC and chiral Lagrangians and their
relations to the structure functions are discussed. Most of them can be
determined in currently ongoing high statistics experiments. Emphasis of the
kinematical analysis is firstly put on decays in
experiments where the neutrino escapes detection and the rest frame
cannot be reconstructed. Subsequently it is shown, how the determination of
hadron tracks in double semileptonic events allows to fully reconstruct the
kinematics. The implications for the spin analysis are indicated.Comment: 12 pages, LaTeX (uses epsf.sty, 3 ps-figures appended as extra
uuencoded file) The complete paper, including figures, is also available via
anonymous ftp at ftp://ttpux2.physik.uni-karlsruhe.de/ttp94-27/ttp94-27.ps,
or via www at http://ttpux2.physik.uni-karlsruhe.de/preprints.htm
Triggering mechanisms of static stress on Mount Etna volcano. An application of the boundary element method
In the last thirty years, numerous eruptions and associated deformation episodes have occurred at Mt. Etna volcano. Datasets recorded by continuous monitoring of these episodes provide a unique opportunity to study the relationships between volcanism, flank instability and faulting activity. We have investigated the stress triggering mechanism between magmatic reservoir inflation, intrusive episodes and flank dynamics. Using three-dimensional numerical Boundary Elements Models we simulated volcano-tectonic events and calculated Coulomb stress changes. Using this modeling approach, we analyzed four realistic scenarios that are representative of recent kinematics occurring at Mt. Etna. The main results obtained highlight how (1) the inflation of a deep spherical magma source transfers elastic stress to a sliding plane and faults (2) the opening of the NE Rift and S Rift
(to a less efficient extent) favor movements of the instable sector and may encourage seismicity on the eastern flank faults, and (3) flank instability may trigger the uprising of magma. Defining the effects of the elastic stress transfer and relationships among the main forces acting on volcano, may help to forecast possible eruption scenarios during future episodes of unrest at Mount Etna and provide an important tool for decision makers during volcanic emergencies involving the highly populated areas of the volcano
The Effectiveness of “Emolabeling” to Promote Healthy Food Choices in Children Preschool Through 5th Grade
Obesity has become a growing global concern. Evidence indicates that ecological factors are most predictive of obesity among children, and that a new strategy, referred to as emolabeling, may effectively address ecological factors, although the extent to which it can influence food choice is not yet known, but tested here. Specifically, we tested the hypothesis that children aged 3 to 11 years will use emolabels, or emotional correlates of health (i.e. healthy-happy, unhealthy-sad), to make healthy food choices. A cross-sectional design was used with two phases. In Phase 1, children were taught how to use emolabels with a “faces of health” lesson. In Phase 2, children made choices between containers that were laid out on a large table in pairs and varied by taste (tastes good, no information), social norms (popular, not popular), branding (image of a minion, no image), or preference (told what food was in each container). A control pair was labeled with only emoticons. The order and presentation of the containers were counterbalanced for each variation. Results showed that a significant proportion of children in the pre-literacy and the early literacy grades used emoticons to specifically make healthy food choices in each variation (p < .05 for all tests), except when children were told what foods were in the containers. In all, emolabeling effectively influenced food choices for healthy foods among children aged 3 to 11 years, more so than labeling for taste, social norms, and branding, but not preference
Monte Carlo study of fermionic trions in a square lattice with harmonic confinement
We investigate the strong-coupling limit of a three-component Fermi mixture
in an optical lattice with attractive interactions. In this limit bound states
(trions) of the three components are formed. We derive an effective Hamiltonian
for these composite fermions and show that it is asymptotically equivalent to
an antiferromagnetic Ising model. By using Monte-Carlo simulations, we
investigate the spatial arrangement of the trions and the formation of a
trionic density wave (CDW), both in a homogeneous lattice and in the presence
of an additional harmonic confinement. Depending on the strength of the
confinement and on the temperature, we found several scenarios for the trionic
distribution, including coexistence of disordered trions with CDW and band
insulator phases. Our results show that, due to a proximity effect, staggered
density modulations are induced in regions of the trap where they would not
otherwise be present according to the local density approximation.Comment: 10 pages, 8 figure
TFPT (TCF3/E2A fusion partner)
Review on TFPT (TCF3/E2A fusion partner), with data on DNA, on the protein encoded, and where the gene is implicated
Limitations on the principle of stationary phase when it is applied to tunneling analysis
Using a recently developed procedure - multiple wave packet decomposition -
here we study the phase time formulation for tunneling/reflecting particles
colliding with a potential barrier. To partially overcome the analytical
difficulties which frequently arise when the stationary phase method is
employed for deriving phase (tunneling) time expressions, we present a
theoretical exercise involving a symmetrical collision between two identical
wave packets and an one-dimensional rectangular potential barrier. Summing the
amplitudes of the reflected and transmitted waves - using a method we call
multiple peak decomposition - is shown to allow reconstruction of the scattered
wave packets in a way which allows the stationary phase principle to be
recovered.Comment: 17 pages, 2 figure
Seismic and Infrasound Signals at Mt. Etna: Modelling the North-East Crater Conduit and its Relation with the 2008-2009 Eruption Feeding System
On 13 May 2008, an eruption began at Mt. Etna from an eruptive fissure that opened on the upper
eastern flank of the volcano. During 12-13 May, 157 infrasonic events, together with the related
seismic transients, were collected. We carried out several analyses to obtain dominant frequencies,
pseudospectrograms, peak-to-peak amplitudes, source locations and time lags between infrasonic
and seismic events. Spectra of the infrasonic events show two main spectral peaks in the frequency
bands ~0.4-0.7 Hz and 1.5-2.0 Hz, respectively. Both infrasonic and seismic events were separately
located below the North-East Crater, where no eruptive activity was observed. Moreover,
significant changes in infrasound spectral content, as well as in the infrasonic-seismic lags, were
found a few hours before the beginning of the eruption. On the basis of the collected information
the infrasound source mechanism was modelled as a superposition of pipe and Helmholtz
resonance, also leading to outline the geometry of the shallower portion of the North-East Crater
plumbing system. The occurrence of these seismo-infrasonic events together with other geological
and geophysical evidences, led us to inferring a direct link between North-East Crater activity and
the eruptive fissure. Further, based on variations over time of both spectral features and seismicinfrasonic
time lag, shallowing phenomena of the free magma column inside North-East Crater
conduit were hypothesized. Such an uprise of magma was likely caused by a pressure increase
inside the plumbing system occurring before the beginning of the 2008-2009 eruption
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