Search results for "selection"

Maintenance of genetic variation in sexual ornamentation : role of precopulatory and postcopulatory sexual selection

2010

Healthy Aging and Sentence Production: Disrupted Lexical Access in the Context of Intact Syntactic Planning.

2020

AbstractHealthy ageing does not affect all features of language processing equally. In this study, we investigated the effects of ageing on different processes involved in fluent sentence production, a complex task that requires the successful execution and coordination of multiple processes. In Experiment 1, we investigated age-related effects on the speed of syntax selection using a syntactic priming paradigm. Both young and older adults produced target sentences quicker following syntactically related primes compared to unrelated primes, indicating that syntactic facilitation effects are preserved with age. In Experiment 2, we investigated age-related effects in syntactic planning and le…

Frequency Range Selection Method for Vibrational Spectra

2018

Theoretical calculations of vibrational properties are widely used to explain and predict experimental spectra. However, with standard quantum chemical methods all molecular motions are considered, which is rather time-consuming for large molecules. Because typically only a specific spectral region is of experimental interest, we propose here an efficient method that allows calculation of only a selected frequency interval. After a computationally cheap low-level estimate of the molecular motions, the computational time is proportional to the number of normal modes needed to describe this frequency range. Results for a medium-sized molecule show a reduction in computational time of up to 1 …

Pattern formation through phase bistability in oscillatory systems with space-modulated forcing.

2010

We propose a novel forcing technique of spatially extended self-oscillatory systems able to excite phase bistability and the dissipative structures associated with it. The forcing is time periodic at a frequency close to the oscillators' frequency and is spatially modulated. The effects of this type of forcing are demonstrated analytically and numerically in a directly driven complex Ginzburg-Landau equation. Both spatially periodic and spatially random drives prove to be effective.

Application of ultra-fast timing techniques to the study of exotic and weakly produced nuclei

2005

Ultra-fast time-delayed techniques have been recently applied in a number of studies where exotic nuclei were identified using advanced selection techniques. These include large Compton-suppressed Ge arrays, in-flight separators or recoil separators. Some of the new results are discussed in this presentation. Besides the results for $^{32}$Mg and $^{96}$Pd, they include the first determination of the half-life of the $8^+$ state in $^{80}$Ge, $T_1/2$ = 2.95(6) ns, and significantly more precise results for $^{51}$Mn (3680 keV level) and $^{48}$V (421 keV level), $T_1/2$ = 1760(40) ps and $T_1/2$ $\leq$ 135 ps, respectively. Development of new scintillators will steadily improve precision an…

Joint constraints on galaxy bias and σ8 through the N-pdf of the galaxy number density

2015

We present a full description of the N-probability density function of the galaxy number density fluctuations. This N-pdf is given in terms, on the one hand, of the cold dark matter correlations and, on the other hand, of the galaxy bias parameter. The method relies on the assumption commonly adopted that the dark matter density fluctuations follow a local non-linear transformation of the initial energy density perturbations. The N-pdf of the galaxy number density fluctuations allows for an optimal estimation of the bias parameter (e.g., via maximum-likelihood estimation, or Bayesian inference if there exists any a priori information on the bias parameter), and of those parameters defining …

An optimized time screening algorithm for ROSAT PSPC and HRI observations

1998

We have developed a model-independent time screening optimization algorithm to cope with significant contamination spikes in the ROSAT PSPC/HRI bacground light-curves. The rejection criteria are based on the maximization of faint sources signal-to-noise ratio. The algorithm tuning parameters have been optimized through performing a wide set of runs on both simulated and real data. We have verified that the application of our selection criteria to the case of long exposure PSPC observations yields an increase of the number of faint sources ( SNR ) of up to 100% with a rejection of up to the 8% of the exposure time. At the same time, we obtain an average signal-to-noise ratio gain of 3% for t…

A Search for Sleptons and Gauginos in Z0 Decays

1990

Using a data sample corresponding to 10 000 hadronic Z0 decays, we have searched for the production of sleptons and gauginos in the two-prong decays of Z0. No candidate remains after straightforward selections. For neutralinos, we use selection methods developed in our previous search for neutral Higgs particles. The negative results are translated into improved mass limits and parameter constraints on the minimal supersymmetric extension of the standard model.

Measurement of the effective Bs0→K+K− lifetime

2012

A precise determination of the effective $B_s^0 \rightarrow K^+ K^-$ lifetime can be used to constrain contributions from physics beyond the Standard Model in the $B_s^0$ meson system. Conventional approaches select $B$ meson decay products that are significantly displaced from the $B$ meson production vertex. As a consequence, $B$ mesons with low decay times are suppressed, introducing a bias to the decay time spectrum which must be corrected. This analysis uses a technique that explicitly avoids a lifetime bias by using a neural network based trigger and event selection. Using 1.0 fb$^{-1}$ of data recorded by the LHCb experiment, the effective $B_s^0 \rightarrow K^+ K^-$ lifetime is meas…

Entanglement Swapping between Discrete and Continuous Variables

2014

We experimentally realize "hybrid" entanglement swapping between discrete-variable (DV) and continuous-variable (CV) optical systems. DV two-mode entanglement as obtainable from a single photon split at a beam splitter is robustly transferred by means of efficient CV entanglement and operations, using sources of squeezed light and homodyne detections. The DV entanglement after the swapping is verified without post-selection by the logarithmic negativity of up to 0.28$\pm$0.01. Furthermore, our analysis shows that the optimally transferred state can be post-selected into a highly entangled state that violates a Clauser-Horne-Shimony-Holt inequality by more than four standard deviations, and …