An Fe Boltzmann temperature lidar was used to obtain the first measurements of middle atmosphere temperatures, Fe densities, and polar mesospheric louds (PMCs) over the North and South Poles during the 1999-2000 summer seasons. The measured temperature structure of the mesopause and lower thermosphere regions in mid-summer at both Poles is consistent with the MSIS90 model. The density profiles ...

Type IV pili (T4P) are surface structures that undergo extension/retraction oscillations to generate cell motility. In Myxococcus xanthus, T4P are unipolarly localized and undergo pole-to-pole oscillations synchronously with cellular reversals. We investigated the mechanisms underlying these oscillations. We show that several T4P proteins localize symmetrically in clusters at both cell poles be...

Mitosis in Surirella is described; this organism displays a number of unusual features including an unorthodox method of chromosome attachment to the spindle, and the differentiation of an extranuclear central spindle from a large spherical organelle named the microtubule center (MC). The MC, present during interphase, breaks down at late prophase as the central spindle is formed. Later, the sp...

The Ross Island Meteorology Experiment (RIME) plans to study the synoptic and mesoscale phenomena along a high-latitude, steep and complex coastline (RIME Workshop Guideline, http://www-bprc.mps.ohio-state.edu/). A key component of RIME is model validation and improvement of physical parameterizations. The Ross Island region is impacted by vigorous storms approaching from the northwest, air-sea...

The south polar region of the Moon contains areas permanently shadowed from solar illumination, which may provide cold traps for volatiles such as water ice. Previous radar studies have emphasized the search for diagnostic polarization signatures of thick ice in areas close to the pole, but near-surface regolith properties and regional geology are also important to upcoming orbital studies of t...

Catastrophe gradient drives anaphase B I t takes a polar catastrophe—oodles of them, actually—to get through anaphase, suggest Cheerambathur et al. on page 995. Their modeling reveals that concentrating microtubule catastrophes near the spindle poles might drive the second half of anaphase. Anaphase in fl y cells is a two-step process: fi rst the chromosomes migrate to the poles (anaphase A), t...