X-ray and neutron scattering

Abstract:

We report the direct measurement of antiferromagnetic spin polarization at the oxygen sites in the multiferroic TbMn2O5, through resonant soft x-ray magnetic scattering. This supports recent theoretical models suggesting that the oxygen spin polarization is key to the magnetoelectric coupling mechanism. The spin polarization is observed through a resonantly enhanced diffraction signal at the oxygen K edge at the commensurate antiferromagnetic wave vector. Using the fdmnes code we have accurately reproduced the experimental data. We have established that the resonance arises through the spin polarization on the oxygen sites hybridized with the square based pyramid Mn3+ ions. Furthermore we have discovered that the position of the Mn3+ ion directly influences the oxygen spin polarization.

Abstract:

Background

Musculoskeletal injuries (MSIs) persist as the leading category of occupational injury in health care. Limited evidence exists regarding MSIs for occupations other than direct patient care providers. An evaluation of the risks, causes and activities associated with MSIs that includes non-patient care health care occupations is warranted.

Aims

To examine the risks and causes of time-loss MSIs for all occupations in health care.

Methods

Workers employed by a health region in British Columbia were followed from April 2007 to March 2008 using payroll data; injuries were followed using an incidence surveillance database. Frequency and rates were calculated for all occupational injuries and MSIs and relative risks (RRs) were computed using Poisson regression. Causes and occupational activities leading to MSIs were tabulated for direct care occupations and non-patient care occupations.

Results

A total of 944 injuries resulting in time-loss from work were reported by 23 742 workers. Overall, 83% injuries were musculoskeletal. The two occupations showing highest RR of MSIs relative to registered nurses were facility support service workers [RR = 3.16 (2.38-4.18), respectively] and care aides [RR=3.76 (3.09-4.59)]. For direct patient care occupations, the leading causes of MSIs were awkward posture (25%) and force (23%); for non-patient care occupations were force (25%) and slip/fall (24%). Patient handling activities accounted for 60% of all MSIs for direct care occupations. For non-patient care occupations, 55% of MSIs were due to material/equipment handling activities.

Conclusions

Prevention efforts for MSIs should be directed to non-patient care occupations as well and consider their occupation-specific causes and activities.

Abstract:

We show that resonant scattering signals at the Bragg forbidden positions in YVO3 originate from the anisotropic nature of the atomic scattering factor. The E1-E1 scattering from the electric-quadrupole moment is explained entirely through the crystal structure and does not require sensitivity to 3d orbital order. Simulations of the resonance using the FDMNES code suggest that the Jahn-Teller distortion provides an insignificant contribution to the intensity of the forbidden reflection. Thus we show that resonant x-ray diffraction at the vanadium K -edge in YVO3 is largely insensitive, even indirectly, to 3d orbital order through Jahn-Teller distortions. © 2010 The American Physical Society.