The Differential Effects of Miras and Mirrors On Eighth-Grade Females' and Males' Ability to Learn Principles of Plane Mirrors

In the United States girls and boys are supposedly afforded the same science education opportunities, yet girls continue to score below boys on standardized science tests. In this study of 101 eighth-grade physical science students, participants took an eight-day class in which they learned the five principles of plane mirrors. Students were randomly assigned to one of three treatment groups using manipulatives: Miras only, Mirrors only, or Miras and Mirrors. Data were analyzed using one-way and two-way ANOVAs. Results indicated that males scored significantly higher than females on the chapter test (p < .05). A significant two-way interaction on a test of retention indicated that females using mirrors only scored lower than males using the combination of Miras and mirrors. Females' and males' ability to learn principles of plane mirrors may be differentially effected by the manipulatives used. Both females and males benefit when Miras and mirrors are used throughout the learning process.     

Comparison of pp and pp interactions at s = 53 GeV

Results are presented from the first p$\text{p}$ colliding beam runs at the CERN ISR, using the UA5 streamer chamber detector. p$\text{p}$ interactions at $\text{s}\text{= 53}\text{GeV}$ are compared with pp data taken in the same experiment. The results are in good agreement with extrapolations of low-energy p$\text{p}$ data.     

Measurement of parity admixtures in nuclear forces in180Hf,181Ta and203Tl

The parity mixing in nuclear states was studied by measuring the circular polarizationP of the γ-radiation emitted from unpolarized nuclei. The analyzer was a “radial transmission magnet” of high symmetry. With 4 NaI scintillation counters and the current integration method 4 independent results were obtained simultaneously. The polarimeter efficiency was determined via the Quadratic Compton effect. Studies of the polarized bremsstrahlung with¹⁷⁰Tm,¹⁷⁷Lu and¹⁹⁸Au sources served as tests for the calculated corrections due to the bremsstrahlung effect. Our results for the circular polarization are:P=?(2.0±0.4) · 10^?3 for the 501 keV transition in¹⁸⁰Hf,p=+(1±4) · 10^?6 for the 482 keV transition in¹⁸¹Ta andP=+(1±7) · 10^?6 for the 279 keV transition in²⁰³Tl. Thus, in the case of¹⁸⁰Hf, the existence of the parity mixing in nuclear states was confirmed.     

LINC-NIRVANA: MCAO toward Extremely Large Telescopes

LINC-NIRVANA is a Fizeau (imaging) interferometer exploiting the full spatial resolution of a 23 m class telescope in the combined beam of the Large Binocular Telescope supported through Multi-Conjugated Adaptive Optics (MCAO). By means of science cases, we show how LINC-NIRVANA takes advantage of the MCAO, increasing the sky coverage of the instrument and the field of view for the Fringe and Flexure tracker. We introduce the MCAO system of LINC-NIRVANA in detail, which in a first step will be installed with two deformable mirrors per arm and has the provision to be upgraded with a third mirror. The MCAO system implements several novel concepts proposed for extremely large telescopes, such as layer oriented MCAO, optical co-adding of guide stars, or Multiple Field of View sensing. LINC-NIRVANA will demonstrate some of the concepts for the first time on sky. To cite this article: W. Gaessler et. al., C. R. Physique 6 (2005).     

The nuclear “Twist”

The nuclear fluid-dynamical Hamiltonian which takes the distortion of the local Fermi surface into account predicts the Twist mode (T=0, J=2^?) at a finite frequency (about 7.5 MeV for²⁰⁸Pb).     

Frobenius distributions of Drinfeld modules over finite fields

We express the weighted class number of Drinfeld -modules of rank two with given characteristic polynomial over the finite field , where as an infinite product of local terms. Some auxiliary results of independent interest about characteristic polynomials of Drinfeld modules are given.

     

Effect of the geometric phase on the dynamics of the hydrogen-exchange reaction

A recent puzzle in nonadiabatic quantum dynamics is that geometric phase (GP) effects are present in the state-to-state opacity functions of the hydrogen-exchange reaction, but cancel out in the state-to-state integral cross sections (ICSs). Here the authors explain this result by using topology to separate the scattering amplitudes into contributions from Feynman paths that loop in opposite senses around the conical intersection. The clockwise-looping paths pass over one transition state (1-TS) and scatter into positive deflection angles; the counterclockwise-looping paths pass over two transition states (2-TS) and scatter into negative deflection angles. The interference between the 1-TS and 2-TS paths thus integrates to a very small value, which cancels the GP effects in the ICS. Quasiclassical trajectory (QCT) calculations reproduce the scattering of the 1-TS and 2-TS paths into positive and negative deflection angles and show that the 2-TS paths describe a direct insertion mechanism. The inserting atom follows a highly constrained "S-bend" path, which allows it to avoid both the other atoms and the conical intersection and forces the product diatom to scatter into high rotational states. By contrast, the quantum 2-TS paths scatter into a mainly statistical distribution of rotational states, so that the quantum 2-TS total ICS is roughly twice the QCT ICS at 2.3 eV total energy. This suggests that the S-bend constraint is relaxed by tunneling in the quantum system. These findings on H+H(2) suggest that similar cancellations or reductions in GP effects are likely in many other reactions.