4,824 research outputs found
Study of the lepton flavor-violating decay
The lepton flavor violating decay is studied in the
context of several extended models that predict the existence of the new gauge
boson named . A calculation of the strength of the lepton flavor
violating coupling is presented by using the most general
renormalizable Lagrangian that includes lepton flavor violation. We used the
experimental value of the muon magnetic dipole moment to bound this coupling,
from which the parameter
is constrained and it is found that
for a
boson mass of 2 TeV. Alongside, we employed the experimental
restrictions over the and processes
in the context of several models that predict the existence of the
gauge boson to bound the mentioned coupling. The most restrictive bounds come
from the calculation of the three-body decay. For this case, it was found that
the most restrictive result is provided by a vector-like coupling, denoted as
, for the case, finding around for a
boson mass of 2 TeV. We used this information to estimate the
branching ratio for the decay. According to the analyzed
models the least optimistic result is provided by the Sequential model,
which is of the order of for a boson mass around 2 TeV.Comment: Revised versio
Physicochemical Factors on The Hydrolysis of Dipyrone
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109863/1/cptclpt2003194.pd
Pharmacokinetics of rofecoxib in children
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109783/1/cptclpt2004285.pd
Crack arrest through branching at curved weak interfaces: an experimental and numerical study
The phenomenon of arrest of an unstably-growing crack due to a curved weak
interface is investigated. The weak interface can produce the deviation of the
crack path, trapping the crack at the interface, leading to stable crack growth
for certain interface geometries. This idea could be used as a technical
solution for a new type of crack arrester, with a negligible impact on the
global stiffness, strength and weight of the structure. In order to exploit
this concept, an experimental campaign based on photo-elasticity and digital
image correlation is carried out, showing the capability of curved weak
interfaces to arrest cracks. The experiment is repeated for several geometrical
configurations through the modification of the interface curvature radii. The
phenomenon of crack deviation and subsequent arrest at the interface is also
investigated with the assistance of a computational model based on the finite
element method. The computational predictions provide the rationale for the
interpretation of the experimental observations, and distinguish between the
different behaviour of concave and convex interfaces. Consequently, as is shown
in the present study, the curved interface concept fosters new routes for the
attainment of structures with enhanced fracture resistance capacities, which
are of paramount importance for materials and components used in extreme
conditions.Comment: 19 pages, 13 figure
Buspirone pharmacokinetics in autistic children
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110082/1/cptclpt2005123.pd
A new method for the solution of the Schrodinger equation
We present a new method for the solution of the Schrodinger equation
applicable to problems of non-perturbative nature. The method works by
identifying three different scales in the problem, which then are treated
independently: An asymptotic scale, which depends uniquely on the form of the
potential at large distances; an intermediate scale, still characterized by an
exponential decay of the wave function and, finally, a short distance scale, in
which the wave function is sizable. The key feature of our method is the
introduction of an arbitrary parameter in the last two scales, which is then
used to optimize a perturbative expansion in a suitable parameter. We apply the
method to the quantum anharmonic oscillator and find excellent results.Comment: 4 pages, 4 figures, RevTex
Charge-Reversal Instability in Mixed Bilayer Vesicles
Bilayer vesicles form readily from mixtures of charged and neutral
surfactants. When such a mixed vesicle binds an oppositely-charged object, its
membrane partially demixes: the adhesion zone recruits more charged surfactants
from the rest of the membrane. Given an unlimited supply of adhering objects
one might expect the vesicle to remain attractive until it was completely
covered. Contrary to this expectation, we show that a vesicle can instead
exhibit {\it adhesion saturation,} partitioning spontaneously into an
attractive zone with definite area fraction, and a repulsive zone. The latter
zone rejects additional incoming objects because counterions on the interior of
the vesicle migrate there, effectively reversing the membrane's charge. The
effect is strongest at high surface charge densities, low ionic strength, and
with thin, impermeable membranes. Adhesion saturation in such a situation has
recently been observed experimentally [H. Aranda-Espinoza {\it et al.}, {\sl
Science} {\bf285} 394--397 (1999)]
Análisis multivariante de los horizontes orgánico-minerales de los suelos del Parque Natural de Sierra Mágina (Jaén)
Soils are described normally using a great number of properties (variables). This generates a great quantity of data not easily understandable in a direct way. Consequently, multivariate analysis is necessary to support and confirm impressions and interpretations of investigations in field and laboratory. In the present work we quantify, through multivariate analysis, the relative influence of the different factors of soil formation that act on the soil system. We have studied 203 organo-mineral horizons, sampled to a depth between 0 and 25 cm of soils in the Sierra Mágina natural park (Jaén, Spain). The studied soils are from calcareous rocks. Five factors were found to be significant and showed that the organic carbon accumulation, decarbonatation and the argillization/rubefacction, as internal variables, and the hill slope, as external variable, they are those which explain a greater percentage of the natural variability of the soil system
Muons in air showers at the Pierre Auger Observatory: Mean number in highly inclined events
We present the first hybrid measurement of the average muon number in air showers at ultrahigh energies, initiated by cosmic rays with zenith angles between 62° and 80°. The measurement is based on 174 hybrid events recorded simultaneously with the surface detector array and the fluorescence detector of the Pierre Auger Observatory. The muon number for each shower is derived by scaling a simulated reference profile of the lateral muon density distribution at the ground until it fits the data. A 10^19 eV shower with a zenith angle of 67°, which arrives at the surface detector array at an altitude of 1450 m above sea level, contains on average (2.68±0.04±0.48(sys))×10^7 muons with energies larger than 0.3 GeV. The logarithmic gain d ln N_μ/dlnE of muons with increasing energy between 4×1018 eV and 5×1019 eV is measured to be (1.029±0.024±0.030(sys)
Shared apical sorting of anion exchanger isoforms AE2a, AE2b1, and AE2b2 in primary hepatocytes
AE2 (SLC4A2) is the member of the Na(+)-independent anion exchanger (AE) family putatively involved in the secretion of bicarbonate to bile. In humans, three variants of AE2 mRNA have been described: the full-length transcript AE2a (expressed from the upstream promoter in most tissues), and alternative transcripts AE2b(1) and AE2b(2) (driven from alternate promoter sequences in a tissue-restricted manner, mainly in liver and kidney). These transcripts would result in AE protein isoforms with short N-terminal differences. To ascertain their translation, functionality, and membrane sorting, we constructed expression vectors encoding each AE2 isoform fused to GFP at the C-terminus. Transfected HEK293 cells showed expression of functional GFP-tagged AE2 proteins, all three isoforms displaying comparable AE activities. Primary rat hepatocytes transfected with expression vectors and repolarized in a collagen-sandwich configuration showed a microtubule-dependent apical sorting of each AE2 isoform. This shared apical sorting is liver-cell specific, as sorting of AE2 isoforms was basolateral in control experiments on polarized kidney MDCK cells. Hepatocytic apical targeting of AE2 isoforms suggests that they all may participate in the canalicular secretion of bicarbonate to bile
- …