580,761 research outputs found
Explicitly broken lepton number at low energy in the Higgs triplet model
We suppose that lepton number is explicitly broken at low energy scale(M) in
the framework of the Higgs triplet() model. The scalar sector of the
model is developed considering the particular assumption
eV. We show that such assumption infers a particular mass spectrum for the
scalars that compose the triplet and cause a decoupling of these scalars from
those that compose the standard scalar doublet.Comment: Minor changes, New references added, To appear at MPL
High temperature control in mediterranean greenhouse production: The constraints and the options
In the open field, the environment is a critical determinant of crop yield and produce quality and it affects the geographical distribution of most crop species. In contrast, in protected cultivation, environmental control allows the fulfillment of the actual needs depending on the technological level. The economic optimum, however, depends on the trade-off between the costs of increased greenhouse control and increase in return, dictated by yield quantity, yield quality and production timing. Additional constraints are increasingly applied for achieving environmental targets. However, the diverse facets of greenhouse technology in different areas of the world will necessarily require different approaches to achieve an improved utilization of the available resources. Although advanced technologies to improve resource use efficiency can be developed as a joint effort between different players involved in greenhouse technology, some specific requirements may clearly hinder the development of common âEuropeanâ resource management models that, conversely should be calibrated for different environments. For instance, the quantification and control of resource fluxes can be better accomplished in a relatively closed and fully automated system, such as those utilized in the glasshouse of Northern-Central Europe, compared to Southern Europe, where different typologies of semi-open/semi-closed greenhouse systems generally co-exist. Based on these considerations, innovations aimed at improving resource use efficiency in greenhouse agriculture should implement these aspects and should reinforce and integrate information obtained from different research areas concerning the greenhouse production. Advancing knowledge on the physiology of high temperature adaptation, for instance, may support the development and validation of models for optimizing the greenhouse system and climate management in the Mediterranean. Overall, a successful approach will see horticulturists, plant physiologists, engineers and economists working together toward the definition of a sustainable greenhouse system
REPLY TO HEP-PH/0211241 "On the extra factor of two in the phase of neutrino oscillations"
Arguments continue to appear in the literature concerning the validity of the
standard oscillation formula. We point out some misunderstandings and try to
explain in simple terms our viewpoint.Comment: 4 pages [1 colored LaTex-fig], AMS-Te
Wave packets and quantum oscillations
We give a detailed analysis of the oscillation formula within the context of
the wave packet formalism. Particular attention is made to insure flavor
eigenstate creation in the physical cases (Delta p not equal 0). This
requirement imposes non instantaneous particle creation in all frames. It is
shown that the standard formula is not only exact when the mass wave packets
have the same velocity, but it is a good approximation when minimal slippage
occurs. For more general situations the oscillation formula contains additional
arbitrary parameters, which allows for the unknown form of the wave packet
envelope.Comment: 15 pages [8 figs], AMS-Te
Quaternionic Electroweak Theory and CKM Matrix
We find in our quaternionic version of the electroweak theory an apparently
hopeless problem: In going from complex to quaternions, the calculation of the
real-valued parameters of the CKM matrix drastically changes. We aim to explain
this quaternionic puzzle.Comment: 8, Revtex, Int. J. Theor. Phys. (to be published
Plume radiation program
Computer program determines the radiant flux to the base region of a real gas system with an axisymmetric geometry and any axisymmetric property distribution
Mapping the train model for earthquakes onto the stochastic sandpile model
We perform a computational study of a variant of the ``train'' model for
earthquakes [PRA 46, 6288 (1992)], where we assume a static friction that is a
stochastic function of position rather than being velocity dependent. The model
consists of an array of blocks coupled by springs, with the forces between
neighbouring blocks balanced by static friction. We calculate the probability,
P(s), of the occurrence of avalanches with a size s or greater, finding that
our results are consistent with the phenomenology and also with previous models
which exhibit a power law over a wide range. We show that the train model may
be mapped onto a stochastic sandpile model and study a variant of the latter
for non-spherical grains. We show that, in this case, the model has critical
behaviour only for grains with large aspect ratio, as was already shown in
experiments with real ricepiles. We also demonstrate a way to introduce
randomness in a physically motivated manner into the model.Comment: 14 pages and 6 figures. Accepted in European Physical Journal
Output functions and fractal dimensions in dynamical systems
We present a novel method for the calculation of the fractal dimension of
boundaries in dynamical systems, which is in many cases many orders of
magnitude more efficient than the uncertainty method. We call it the Output
Function Evaluation (OFE) method. The OFE method is based on an efficient
scheme for computing output functions, such as the escape time, on a
one-dimensional portion of the phase space. We show analytically that the OFE
method is much more efficient than the uncertainty method for boundaries with
, where is the dimension of the intersection of the boundary with a
one-dimensional manifold. We apply the OFE method to a scattering system, and
compare it to the uncertainty method. We use the OFE method to study the
behavior of the fractal dimension as the system's dynamics undergoes a
topological transition.Comment: Uses REVTEX; to be published in Phys. Rev. Let
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