Constructing Regularized Cosmic Propagators

We present a new scheme for the general computation of cosmic propagators that allow to interpolate between standard perturbative results at low-k and their expected large-k resummed behavior. This scheme is applicable to any multi-point propagator and allows the matching of perturbative low-k calculations to any number of loops to their large-k behavior, and can potentially be applied in case of non-standard cosmological scenarios such as those with non-Gaussian initial conditions. The validity of our proposal is checked against previous prescriptions and measurements in numerical simulations showing a remarkably good agreement. Such a generic prescription for multi-point propagators provides the necessary building blocks for the computation of polyspectra in the context of the so-called Gamma-expansion introduced by Bernardeau et al. (2008). As a concrete application we present a consistent calculation of the matter bispectrum at one-loop order.Comment: 21 pages, 14 figures. v2: corrections in response to referee repor

Killing and replacing queen-laid eggs: low cost of worker policing in the honey bee

Worker honeybees, Apis mellifera, police each other’s reproduction by killing worker-laid eggs. Previous experiments demonstrated that worker policing is effective, killing most (∼98%) worker-laid eggs. However, many queen-laid eggs were also killed (∼50%) suggesting that effective policing may have high costs. In these previous experiments, eggs were transferred using forceps into test cells, mostly into unrelated discriminator colonies. We measured both the survival of unmanipulated queen-laid eggs and the proportion of removal errors that were rectified by the queen laying a new egg. Across 2 days of the 3-day egg stage, only 9.6% of the queen-laid eggs in drone cells and 4.1% in worker cells were removed in error. When queen-laid eggs were removed from cells, 85% from drone cells and 61% from worker cells were replaced within 3 days. Worker policing in the honeybee has a high benefit to policing workers because workers are more related to the queen’s sons (brothers, r = 0.25) than sister workers’ sons (0.15). This study shows that worker policing also has a low cost in terms of the killing of queen-laid eggs, as only a small proportion of queen-laid eggs are killed, most of which are rapidly replaced

Implementing a simple continuous speech recognition system on an FPGA

Speech recognition is a computationally demanding task, particularly the stage which uses Viterbi decoding for converting pre-processed speech data into words or sub-word units. We present an FPGA implementations of the decoder based on continuous hidden Markov models (HMMs) representing monophones, and demonstrate that it can process speech 75 times real time, using 45% of the slices of a Xilinx Virtex XCV100

Speech Recognition on an FPGA Using Discrete and Continuous Hidden Markov Models

Speech recognition is a computationally demanding task, particularly the stage which uses Viterbi decoding for converting pre-processed speech data into words or sub-word units. Any device that can reduce the load on, for example, a PC’s processor, is advantageous. Hence we present FPGA implementations of the decoder based alternately on discrete and continuous hidden Markov models (HMMs) representing monophones, and demonstrate that the discrete version can process speech nearly 5,000 times real time, using just 12% of the slices of a Xilinx Virtex XCV1000, but with a lower recognition rate than the continuous implementation, which is 75 times faster than real time, and occupies 45% of the same device

New experimental evidence that the proton develops asymptotically into a black disk

Recently, the Auger group has extracted the proton-air cross section from observations of air showers produced by cosmic ray protons (and nuclei) interacting in the atmosphere and converted it into measurements of the total and inelastic $pp$ cross sections $\sigma_{\rm tot}$ and $\sigma_{\rm inel}$ at the super-LHC energy of 57 TeV. Their results reinforce our earlier conclusions that the proton becomes a black disk at asymptotic energies, a prediction reached on the basis of sub-LHC \pbar p and $pp$ measurements of $\sigma_{\rm tot}$ and $\rho$, the ratio of the real to the imaginary part of the forward scattering amplitude [M. M. Block and F. Halzen, Phys. Rev. Lett. {\bf 107}, 212002 (2011)]. The same black disk description of the proton anticipated the values of $\sigma_{\rm tot}$ and $\sigma_{\rm inel}$ measured by the TOTEM experiment at the LHC cms (center of mass) energy of $\sqrt s=7$ TeV, as well as those of $\sigma_{\rm inel}$ measured by ALICE, ATLAS and CMS, as well as the ALICE measurement at 2.76 TeV. All data are consistent with a proton that is asymptotically a black disk of gluons: (i) both $\sigma_{\rm tot}$ and $\sigma_{\rm inel}$ behave as $\ln^2s$, saturating the Froissart bound, (ii) the forward scattering amplitude becomes pure imaginary (iii) the ratio $\sigma_{\rm inel}/\sigma_{\rm tot}=0.509 \pm 0.021$, compatible with the black disk value of 1/2, and (iv) proton interactions become flavor blind.Comment: 4 pages, 3 figure

Forward hadronic scattering at 8 TeV: predictions for the LHC

The Large Hadron Collider (LHC) recently started operating at 8 TeV. In this note, we update our earlier LHC forward hadronic scattering predictions \cite{physicsreports,update7, blackdisk}, giving new predictions, including errors, for the $pp$ total and inelastic cross sections, the $\rho$-value, the nuclear slope parameter $B$, $d\sigma_{\rm el}/dt$, and the large gap survival probability at 8 TeV.Comment: 4 pages, 1 figure, 1 table. arXiv admin note: substantial text overlap with arXiv:1102.316