The Development of a Cognitive Skills Training to Support Driver Education – Comparing Performance of Experienced and Trained Learner Drivers

Deficits in cognitive skills such as hazard perception are considered one of the major factors explaining the high numbers of crashes for novice drivers. Computer based trainings (CBTs) have been identified as a potential measure to improve such skills. Several CBTs have been developed since. Some of them have been evaluated, however, only by comparing a treatment group and a control group. While results show that the evaluated CBTs are somewhat effective, it is unclear how an experienced driver would have performed in the test scenarios. We developed our own CBT, and in a first step, evaluated it following the same known strategy (treatment and control group, adding a “paper based training group). Results provided evidence for the assumption that the CBT had a positive effect on learner drivers’ glance behaviour in simulated driving (Petzoldt et al., 2013). However, after we confirmed the effectiveness, we tested a group of experienced drivers on exactly the same simulator scenarios. The comparison between treatment, control and experienced driver group is presented in this paper. Results show comparable patterns of glance behaviour for the treatment group and the experienced drivers, superior to that of the control group. Driving performance rated by experts was mostly appropriate for all groups, with notable exceptions for some scenarios

Communications Biophysics

Contains reports on three research projects.United States Air Force (Contract AF19(604)-4112

Ellipticals at z=0 from Self-Consistent Hydrodynamical Simulations: Clues on Age Effects in their Stellar Populations

We present results of a study of the stellar age distributions in the sample of elliptical-like objects (ELOs) identified at z=0 in four simulations operating in the context of a concordance cosmological model. The simulations show that the formation of most stars in each ELO of the sample is a consequence of violent dynamical events, either fast multiclump collapse at high z, or mergers at lower z. This second way can explain the age spread as well as the dynamical peculiarities observed in some ellipticals, but its relative weight is never dominant and decreases as the ELO mass at the halo scale, $M_{vir}$, increases, to such an extent that some recent mergers contributing an important fraction to the total ELO mass can possibly contribute only a small fraction of new born stars. More massive objects have older means and narrower spreads in their stellar age distributions than less massive ones. The ELO sample shows also a tight correlation between $M_{vir}$ and the central stellar l.o.s. velocity dispersion, $\sigma_{los}$. This gives a trend of the means and spreads of ELO stellar populations with $\sigma_{los}$ that is consistent, even quantitatively, with the age effects observationally detected in the stellar populations of elliptical galaxies. Therefore, these effects can be explained as the observational manifestation of the intrinsic correlations found in the ELO sample between $M_{vir}$ and the properties of the stellar age distribution, on the one hand, and $M_{vir}$ and $\sigma_{los}$, on the other hand. These correlations hint, for the first time, at a possible way to reconcile age effects in ellipticals, and, particularly, the increase of $\alpha /$ ratios with $\sigma_{los}$, with the hierarchical clustering paradigm.Comment: 13 pages, 2 figures, accepted for publication in Astrophysical Journal Letter

MOST photometry of the RRd Lyrae variable AQ Leo: Two radial modes, 32 combination frequencies, and beyond

Highly precise and nearly uninterrupted optical photometry of the RR Lyrae star AQ Leo was obtained with the MOST (Microvariability & Oscillations of STars) satellite over 34.4 days in February-March 2005. AQ Leo was the first known double-mode RR Lyrae pulsator (RRd star). Three decades after its discovery, MOST observations have revealed that AQ Leo oscillates with at least 42 frequencies, of which 32 are linear combinations (up to the sixth order) of the radial fundamental mode and its first overtone. Evidence for period changes of these modes is found in the data. The other intrinsic frequencies may represent an additional nonradial pulsation mode and its harmonics (plus linear combinations) which warrant theoretical modeling. The unprecedented number of frequencies detected with amplitudes down to millimag precision also presents an opportunity to test nonlinear theories of mode growth and saturation in RR Lyrae pulsators.Comment: accepted for publication in MNRAS; revision v2 : broken references have been fixe

Cosmological formation and chemical evolution of an elliptical galaxy

We aim at studying the effect of a cosmologically motivated gas infall law for the formation of a massive elliptical galaxy in order to understand its impact on the formation of the spheroids. We replace the empirical infall law of the model by Pipino & Matteucci with a cosmologically derived infall law for the formation of an elliptical galaxy. We constrast our predictions with observations. We also compare the obtained results with those of Pipino & Matteucci. We computed models with and without galactic winds: we found that models without wind predict a too large current SNIa rate. In particular, the cosmological model produces a current SNIa which is about ten times higher than the observed values. Moreover models without wind predict a large current SNII rate, too large even if compared with the recent GALEX data. The predicted SNII rate for the model with wind, on the other hand, is too low if compared with the star formation histories given by GALEX. Last but not least, the mean value for the [Mg/Fe] ratio in the dominant stellar population of the simulated galaxy, as predicted by the cosmological model, is too low if compared to observations. This is, a very important result indicating that the cosmological infall law is in contrast with the chemical evolution. A cosmologically derived infall law for an elliptical galaxy cannot reproduce all the chemical constraints given by the observations. The problem resides in the fact that the cosmologically derived infall law implies a slow gas accretion with consequent star formation rate active for a long period. In this situation low [Mg/Fe] ratios are produced for the dominant stellar population in a typical elliptical, at variance with observations.Comment: 8 pages, 6 figures, accepted for publication by A&

A polymorphism of a platelet glycoprotein receptor as an inherited risk factor for coronary thrombosis.

BACKGROUND: Platelet glycoprotein IIb/IIIa is a membrane receptor for fibrinogen and von Willebrand factor, and it has an important role in platelet aggregation. It is known to be involved in the pathogenesis of acute coronary syndromes. Previously, we found a high frequency of a particular polymorphism, PlA2, of the gene encoding glycoprotein IIIa in kindreds with a high prevalence of premature myocardial infarction. METHODS: To investigate the relation between the PlA2 polymorphism and acute coronary syndromes, we conducted a case-control study of 71 case patients with myocardial infarction or unstable angina and 68 inpatient controls without known heart disease. The groups were matched for age, race, and sex. We used two methods to determine the PlA genotype: reverse dot blot hybridization and allele-specific restriction digestion. RESULTS: The prevalence of PlA2 was 2.1 times higher among the case patients than among the controls (39.4 percent vs. 19.1 percent, P=0.01). In a subgroup of patients whose disease began before the age of 60 years, the prevalence of PlA2 was 50 percent, a value that was 3.6 times that among control subjects under 60 years of age (13.9 percent, P=0.002). Among subjects with the PlA2 polymorphism, the odds ratio for having a coronary event was 2.8 (95 percent confidence interval, 1.2 to 6.4). In the patients less than 60 years of age at the onset of disease, the odds ratio was 6.2 (95 percent confidence interval, 1.8 to 22.4). CONCLUSIONS: We observed a strong association between the PlA2 polymorphism of the glycoprotein IIIa gene and acute coronary thrombosis, and this association was strongest in patients who had had coronary events before the age of 60 years

Effective lattice theories for Polyakov loops

We derive effective actions for SU(2) Polyakov loops using inverse Monte Carlo techniques. In a first approach, we determine the effective couplings by requiring that the effective ensemble reproduces the single-site distribution of the Polyakov loops. The latter is flat below the critical temperature implying that the (untraced) Polyakov loop is distributed uniformly over its target space, the SU(2) group manifold. This allows for an analytic determination of the Binder cumulant and the distribution of the mean-field, which turns out to be approximately Gaussian. In a second approach, we employ novel lattice Schwinger-Dyson equations which reflect the SU(2) x SU(2) invariance of the functional Haar measure. Expanding the effective action in terms of SU(2) group characters makes the numerics sufficiently stable so that we are able to extract a total number of 14 couplings. The resulting action is short-ranged and reproduces the Yang-Mills correlators very well.Comment: 27 pages, 8 figures, v2: method refined, chapter and references adde

BRITE-Constellation reveals evidence for pulsations in the enigmatic binary η\eta Carinae

$\eta$ Car is a massive, eccentric binary with a rich observational history. We obtained the first high-cadence, high-precision light curves with the BRITE-Constellation nanosatellites over 6 months in 2016 and 6 months in 2017. The light curve is contaminated by several sources including the Homunculus nebula and neighboring stars, including the eclipsing binary CPD$-$59$^\circ$2628. However, we found two coherent oscillations in the light curve. These may represent pulsations that are not yet understood but we postulate that they are related to tidally excited oscillations of $\eta$ Car's primary star, and would be similar to those detected in lower-mass eccentric binaries. In particular, one frequency was previously detected by van Genderen et al. and Sterken et al. through the time period of 1974 to 1995 through timing measurements of photometric maxima. Thus, this frequency seems to have been detected for nearly four decades, indicating that it has been stable in frequency over this time span. These pulsations could help provide the first direct constraints on the fundamental parameters of the primary star if confirmed and refined with future observations.Comment: 8 pages, 4 figures, accepted to MNRA

Sixteen years of Collaborative Learning through Active Sense-making in Physics (CLASP) at UC Davis

This paper describes our large reformed introductory physics course at UC Davis, which bioscience students have been taking since 1996. The central feature of this course is a focus on sense-making by the students during the five hours per week discussion/labs in which the students take part in activities emphasizing peer-peer discussions, argumentation, and presentations of ideas. The course differs in many fundamental ways from traditionally taught introductory physics courses. After discussing the unique features of CLASP and its implementation at UC Davis, various student outcome measures are presented showing increased performance by students who took the CLASP course compared to students who took a traditionally taught introductory physics course. Measures we use include upper-division GPAs, MCAT scores, FCI gains, and MPEX-II scores.Comment: Also submitted to American Journal of Physic

Zero-bias anomalies on Sr0.88_{0.88}La0.12_{0.12}CuO2_2 thin films

High-impedance contacts made on the surface of Sr$_{0.88}$La$_{0.12}$CuO$_2$ superconducting thin films systematically display a zero-bias anomaly. We consider two-level systems (TLS) as the origin of this anomaly. We observe that the contribution of some TLS to the contact resistance is weakened by a magnetic field. We show that this could result from the increase of the TLS relaxation rate in the superconducting state, due to its ability to create pairs of quasiparticles out of the condensate, when located close to the surface of the film