611 research outputs found
The economical 3-3-1 model revisited
We show that the economical 3-3-1 model poses a very high new physics scale
of the order of 1000~TeV due to the constraint on the flavor-changing neutral
current. The implications of the model for neutrino masses, inflation,
leptogenesis, and superheavy dark matter are newly recognized. Alternatively,
we modify the model by rearranging the third quark generation differently from
the first two quark generations, as well as changing the scalar sector. The
resultant model now predicts a consistent new physics at TeV scale unlike the
previous case and may be fully probed at the current colliders. Particularly,
due to the minimal particle contents, the models under consideration manifestly
accommodate dark matter candidates and neutrino masses, with novel and distinct
production mechanisms. The large flavor-changing neutral currents that come
from the ordinary and exotic quark mixings can be avoided due to the
approximate symmetry.Comment: 21 pages; english writing improved, dark matter stability stated, and
references added; matches journal versio
A new carrier frequency estimator for modem signals
Journal ArticleABSTRACT A novel carrier frequency estimation scheme for a relatively broad class of voiceband data signals (modem signals) is presented in this paper. The class of signals being studied includes different types of phase-shift-keyed (PSK) and frequency-shift-keyed (FSK) signals. The frequency estimates are obtained by averaging the estimates of the derivative of the instantaneous signal phase after discarding the estimates at the baud boundaries. Experimental results illustrate that the frequency estimates obtained from our scheme are unbiased and have small variances. Results also show that the carrier frequency estimation scheme presented here is superior to two other techniques in terms of both the mean and variance of the carrier frequency estimates
A baseband residual vector quantization algorithm for voiceband data signals
Journal ArticleAbstract-In this paper, we present a new approach to the digitization and compression of a class of voiceband modem signals. Our approach, which we call baseband residual vector quantization (BRVQ), relies heavily upon the simple structure present in a modem signal. After the signal is converted to baseband, the magnitude sequence and the sequence of residuals obtained when the phase within each baud of the baseband signal is modeled by a straight line are separately vector quantized. In order to carry out these operations, we developed the new carrier-frequency estimation and baud-rate classification schemes described in the paper. Experimental results show that the performance of the BRVQ system at and below 16 kbits/s is better than that of a previously developed vector quantization scheme that has itself been shown to outperform traditional speech-compression techniques such as adaptive predictive coding, adaptive transform coding, and subband coding when these techniques are used to compress modem signals
Maize in Vietnam: Production Systems, Constraints, and Research Priorities
Crop Production/Industries,
Fermion masses and mixings and muon anomaly in a 3-3-1 model with family symmetry
We propose a predictive model based on the gauge symmetry, which is supplemented by the family symmetry and
several auxiliary cyclic symmetries whose spontaneous breaking produces the
observed SM fermion mass and mixing pattern. The masses of the light active
neutrinos are produced by an inverse seesaw mechanism mediated by three right
handed Majorana neutrinos. To the best of our knowledge the model corresponds
to the first implementation of the family symmetry in a theory with three right handed Majorana neutrinos and
inverse seesaw mechanism. Our proposed model successfully accommodates the
experimental values of the SM fermion mass and mixing parameters, the muon
anomalous magnetic moment as well as the Higgs diphoton decay rate constraints.
The consistency of our model with the muon anomalous magnetic moment requires
electrically charged scalar masses at the sub TeV scale.Comment: 17 page
ULTRA-TRACE DETERMINATION OF IRIDIUM BY ETV/ICP-MS USING CHEMICAL MODIFIERS
Joint Research on Environmental Science and Technology for the Eart
Pharmacology and clinical drug candidates in redox medicine
SIGNIFICANCE
Oxidative stress is suggested to be a disease mechanism common to a wide range of disorders affecting human health. However, so far, the pharmacotherapeutic exploitation of this, for example, based on chemical scavenging of pro-oxidant molecules, has been unsuccessful. Recent Advances: An alternative emerging approach is to target the enzymatic sources of disease-relevant oxidative stress. Several such enzymes and isoforms have been identified and linked to different pathologies. For some targets, the respective pharmacology is quite advanced, that is, up to late-stage clinical development or even on the market; for others, drugs are already in clinical use, although not for indications based on oxidative stress, and repurposing seems to be a viable option.
CRITICAL ISSUES
For all other targets, reliable preclinical validation and drug ability are key factors for any translation into the clinic. In this study, specific pharmacological agents with optimal pharmacokinetic profiles are still lacking. Moreover, these enzymes also serve largely unknown physiological functions and their inhibition may lead to unwanted side effects.
FUTURE DIRECTIONS
The current promising data based on new targets, drugs, and drug repurposing are mainly a result of academic efforts. With the availability of optimized compounds and coordinated efforts from academia and industry scientists, unambiguous validation and translation into proof-of-principle studies seem achievable in the very near future, possibly leading towards a new era of redox medicine
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