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Reinforcement of pedicle screws using PMMA augmentation may be a feasible surgical technique for osteoporotic spines.

The impact of Arctic radiosonde observations on the forecasting of the 2012 early August Arctic cyclone AC12-the "strongest" since records began-has been investigated using an observing system experiment (OSE). An atmospheric ensemble reanalysis (ALERA2) was used as the control experiment (CTL) to reproduce the development of the Arctic cyclone and surrounding large-scale atmospheric fields. The OSE applies the same reanalysis as the CTL except for the exclusion of radiosonde observations from the German icebreaker Polarstern, which cruised near Svalbard during mid-July to early August 2012. Comparison of the two reanalyses revealed a difference in the upper tropospheric circulation over northern mid-Eurasia, just before the Arctic cyclone developed, in the form of a stronger tropopause polar vortex in the CTL. This indicated that the upper tropospheric field in the CTL had greater potential for baroclinic instability over mid-Eurasia. Ensemble predictions were then conducted using the two reanalyses as initial values at which the tropopause polar vortex approached northern mid-Eurasia. The CTL prediction reproduced the formation of the Arctic cyclone, but the OSE shows a significantly weaker one. These results indicate that the improved reproduction of upper tropospheric circulation in the Arctic region due to additional radiosonde observations from a mobile platform was indispensable for the prediction of AC12. In particular, observations being acquired far from the Arctic cyclone affect the prediction of the cyclone via the upper tropospheric circulation in the atmospheric west wind drift.

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Prophylactic bilateral C4/C5 microforaminotomy significantly decreased the incidence of postoperative C5 palsy. These results suggest that the main etiology of C5 palsy was C5 root impairment. However, 2 patients experienced C5 palsy despite undergoing prophylactic foraminotomy, which indicated that other factors including spinal cord impairment after acute decompression against cervical canal stenosis may also be considered as minor etiologies of C5 palsy. We conclude that prophylactic C4/C5 foraminotomy was an effective preventive measure against postoperative C5 palsy after laminoplasty.

A new block maintenance mechanism, the selective absorption mechanism (SAM), is proposed. According to this mechanism, which is based on vortex-vortex interactions (i.e., the interactions between a blocking anticyclone and synoptic eddies with the same polarity), a blocking anticyclone actively and selectively absorbs synoptic anticyclones (strictly, air parcels with low potential vorticity). The blocking anticyclone, which is thus supplied with low potential vorticity of the synoptic anticyclones, can subsist for a prolonged period, withstanding dissipation.The SAM was verified in a case study through trajectory analysis. Ten actual cases of blocking were examined. Trajectories were calculated by tracing parcels originating from synoptic anticyclones and cyclones located upstream of the blocking. Parcels starting from anticyclones were attracted to and absorbed by the blocking anticyclone, whereas parcels from cyclones were repelled by the blocking anticyclone and attracted to the blocking cyclone, if one was present.The results show that the SAM is effective in the maintenance of observed cases of blocking. In addition, the uniqueness and distinction of the SAM from other previously proposed maintenance mechanisms are discussed.

We use a one-shot measurement technique to study effects of laser prepulses on the electron laser wakefield acceleration driven by relativistically intense laser pulses (lambda=790 nm, 11 TW, 37 fs) in dense helium gas jets. A quasimonoenergetic electron bunch with an energy peak approximately 11.5 MeV[DeltaE/E approximately 10% (FWHM)] and with a narrow-cone angle (0.04pi mm mrad) of ejection is detected at a plasma density of 8 x 10(19) cm(-3). A strong correlation between the generation of monoenergetic electrons and optical guiding of the pulse in a thin channel produced by picosecond laser prepulses is observed. This generation mechanism is well corroborated by two-dimensional particle-in-cell simulations.