Ultrafast magnetization reversal dynamics investigated by time domain imaging

Spatiotemporal magnetization reversal dynamics in a Ni(80)Fe(20) microstructure is studied using ps time scale scanning Kerr microscopy. Time domain images reveal a striking change in the reversal associated with the reduction in switching time when a transverse bias field is applied. Magnetization oscillations subsequent to reversal are observed at two resonance frequencies, which sensitively depend on the bias field strength. The oscillation at f = 2 GHz is caused by the damped precession of M, while the lower frequency approximately 0.8 GHz mode is interpreted in terms of domain wall oscillation.     

Neutron spectra at 0° from (p,n) reactions on 9Be, 12C,and 27Al at 647 and 800 MeV

The measured cross sections show a narrow high-energy peak (20–30 MeV/cFWHM) and a broad bump at lower momenta associated with pion production. Comparison is made to an intranuclear cascade calculation.     

Mathematical features of lessons in the TIMSS video study

The video component of the Third International Mathematics and Science Study marked the first time that national samples of teachers were videotaped at work in their classrooms. In this article we review some of the results of the study, with special attention to the nature of the mathematics evident in these eighth-grade lessons from Germany, Japan, and the United States. We conclude by proposing that many lessons within a country follow a cultural pattern of teaching, and that differences among countries on individual indicators of teaching must be understood in reference to these patterns.     

Total synthesis of ionomycin using ring-opening strategies

[structure: see text] The total synthesis of the polyether antibiotic ionomycin, a calcium ionophore, is described. The synthesis demonstrates the utility of ring-opening methodologies as applied to the synthesis of polypropionate and deoxypolypropionate subunits, which are found in two of the four fragments in the synthesis.     

Measurements of the neutron-proton analyzing power in the energy range from 17 to 50 MeV

Measurements of the analyzing power A_y for neutron-proton scattering in the energy range from 17 to 50 MeV are reported. These data improve considerably the precision of the np data base in this energy range. Preliminary phase-shift analyses indicate reduced uncertainties in the np ³P(T = 1) phases and in the ³D(T = 0) phase shifts.     

Toward an enantioselective total synthesis of sarain A: construction of an advanced intermediate and rearrangement of the sarain A core under mild conditions

A high-yielding N-sulfonyliminium ion-enoxysilane cyclization and a ring-closing metathesis are key steps in the enantioselective synthesis of late-stage intermediates en route to sarain A. Also revealed is an unprecedented rearrangement of the tetracyclic sarain A core under mildly acidic conditions. [structure: see text]