Goldstein-Kac telegraph processes with random speeds: Path probabilities, likelihoods, and reported Lévy flights.

The Goldstein-Kac telegraph process describes the one-dimensional motion of particles with constant speed undergoing random changes in direction. Despite its resemblance to numerous real-world phenomena, the singular nature of the resultant spatial distribution of each particle precludes the possibility of any a posteriori empirical validation of this random-walk model from data. Here we show that by simply allowing for random speeds, the ballistic terms are regularized and that the diffusion component can be well-approximated via the unscented transform. The result is a computationally efficient yet robust evaluation of the full particle path probabilities and, hence, the parameter likelihoods of this generalized telegraph process. We demonstrate how a population diffusing under such a model can lead to non-Gaussian asymptotic spatial distributions, thereby mimicking the behavior of an ensemble of Lévy walkers

Design of low level RF control for the TESLA superstructure

The superstructure is a viable option for the TESLA linear collider because of a high effective gradient and a reduced number of rf components. However, the high number and close proximity of passband modes impose challenging demands on the rf control system. The control problem is complicated by the fact that the cavity probe signal does not exactly reflect the actual accelerating voltage experienced by the beam due to the different coupling of the generator, pickup probe and beam to the FM passband modes. The digital control system developed for the standard 9-cell cavity is not adequate for operation of the superstructure. As discussed in this paper, an additional filter is needed to guarantee robustness and stability. Based on rf control simulations the filter characteristic is optimized

RF Parameters and Field Stability Requirements for the Cornell ERL

Abstract Cornell University, in collaboration with Jefferson Laboratory, has proposed the construction of a prototype energyrecovery linac (ERL) to study the energy recovery concept with high current, low emittance beams OVERVIEW The schematic of the injector RF system is shown in The main linac with energy recovery is based on five superconducting 9-cell cavities, each with its own field control system and klystron; see INJECTOR CAVITIES Buncher Cavity: The buncher cavity is a normal-conducting single-cell cavity made of copper. It is used to produce a correlated energy variation of about 10 keV along a σ gun = 12 ps, 500 keV bunch coming from the gun. This will shorten the bunch to σ inj = 2.3 ps in a drift space between the buncher cavity and first superconducting cavity. The RF properties [4] of the buncher cavity are listed in • offcrest, i.e. during zero-crossing. The RF power required to maintain a constant field in the cavity is then given b

iBench: A ground truth approach for advanced validation of mass spectrometry identification method

The discovery of many noncanonical peptides detectable with sensitive mass spectrometry inside, outside, and on cells shepherded the development of novel methods for their identification, often not supported by a systematic benchmarking with other methods. We here propose iBench, a bioinformatic tool that can construct ground truth proteomics datasets and cognate databases, thereby generating a training court wherein methods, search engines, and proteomics strategies can be tested, and their performances estimated by the same tool. iBench can be coupled to the main database search engines, allows the selection of customized features of mass spectrometry spectra and peptides, provides standard benchmarking outputs, and is open source. The proof-of-concept application to tryptic proteome digestions, immunopeptidomes, and synthetic peptide libraries dissected the impact that noncanonical peptides could have on the identification of canonical peptides by Mascot search with rescoring via Percolator (Mascot+Percolator)