42,063 research outputs found
Transistorized Marx bank pulse circuit provides voltage multiplication with nanosecond rise-time
Base-triggered avalanche transistor circuit used in a Marx bank pulser configuration provides voltage multiplication with nanosecond rise-time. The avalanche-mode transistors replace conventional spark gaps in the Marx bank. The delay time from an input signal to the output signal to the output is typically 6 nanoseconds
Risk-Management Practices for Specialty-Crop Producers in California, Florida, New York, and Pennsylvania
Crop Production/Industries, Risk and Uncertainty,
Efficient quantile regression for heteroscedastic models
Quantile regression (QR) provides estimates of a range of conditional quantiles. This stands in contrast to traditional regression techniques, which focus on a single conditional mean function. Lee et al. [Regularization of case-specific parameters for robustness and efficiency. Statist Sci. 2012;27(3):350–372] proposed efficient QR by rounding the sharp corner of the loss. The main modification generally involves an asymmetric ℓ₂ adjustment of the loss function around zero. We extend the idea of ℓ₂ adjusted QR to linear heterogeneous models. The ℓ₂ adjustment is constructed to diminish as sample size grows. Conditions to retain consistency properties are also provided
Top quark asymmetry from a non-Abelian horizontal symmetry
Motivated by the persistence of a large measured top quark forward-backward
asymmetry at the Tevatron, we examine a model of non-Abelian flavor gauge
symmetry. The exchange of the gauge bosons in the -channel can give a large
asymmetry due to the forward Rutherford scattering peak. We address generic
constraints on non-Abelian -channel physics models including flavor diagonal
resonances and potentially dangerous contributions to inclusive top pair cross
sections. We caution on the general difficulty of comparing theoretical
predictions for top quark signals to the existing experimental results due to
potentially important acceptance effects. The first signature at the Large
Hadron Collider can be a large inclusive top pair cross section, or like-sign
dilepton events, although the latter signal is much smaller than in Abelian
models. Deviations of the invariant mass distributions at the LHC will also be
promising signatures. A more direct consistency check of the Tevatron asymmetry
through the LHC asymmetry is more likely to be relevant at a later stage.Comment: 21 pages, 7 figure
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