Phonons in random alloys: the itinerant coherent-potential approximation

We present the itinerant coherent-potential approximation(ICPA), an analytic, translationally invariant and tractable form of augmented-space-based, multiple-scattering theory in a single-site approximation for harmonic phonons in realistic random binary alloys with mass and force-constant disorder. We provide expressions for quantities needed for comparison with experimental structure factors such as partial and average spectral functions and derive the sum rules associated with them. Numerical results are presented for Ni_{55} Pd_{45} and Ni_{50} Pt_{50} alloys which serve as test cases, the former for weak force-constant disorder and the latter for strong. We present results on dispersion curves and disorder-induced widths. Direct comparisons with the single-site coherent potential approximation(CPA) and experiment are made which provide insight into the physics of force-constant changes in random alloys. The CPA accounts well for the weak force-constant disorder case but fails for strong force-constant disorder where the ICPA succeeds.Comment: 19 pages, 12 eps figures, uses RevTex

The experience of health in an unequal society

The Politics of Food and Healt

Women’s reasons for, and experiences of, choosing a homebirth following a caesarean section

BACKGROUND: Caesarean section is rising in the developed world and vaginal birth after caesarean (VBAC) is declining. There are increased reports of women seeking a homebirth following a caesarean section (HBAC) in Australia but little is known about the reasons for this study aimed to explore women's reasons for and experiences of choosing a HBAC. METHODS: Twelve women participated in a semi-structured one-to-one interview. The interviews were digitally recorded, then transcribed verbatim. These data were analysed using thematic analysis. RESULTS: The overarching theme that emerged was ‘It’s never happening again’. Women clearly articulated why it [caesarean section] was never happening again under the following sub themes: ‘treated like a piece of meat’, ‘I was traumatised by it for years’, ‘you can smell the fear in the room’, ‘re-traumatised by the system’. They also described how it [caesarean section] was never happening again under the sub themes: ‘getting informed and gaining confidence’, ‘avoiding judgment through selective telling’, ‘preparing for birth’, ‘gathering support’ and ‘all about safety but I came first’. The women then identified the impact of their HBAC under the subthemes ‘I felt like superwoman’ and ‘there is just no comparison’. CONCLUSIONS: Birth intervention may cause physical and emotional trauma that can have a significant impact on some women. Inflexible hospital systems and inflexible attitudes around policy and care led some women to seek other options. Women report that achieving a HBAC has benefits for the relationship with their baby. VBAC policies and practices in hospitals need to be flexible to enable women to negotiate the care that they wish to have

Therapeutic Management of Primary Immunodeficiency in Older Patients

Primary immunodeficiency disease (PID) has traditionally been viewed as a group of illnesses seen in the paediatric age group. New advances in diagnosis and treatment have led to an increase in the number of elderly PID patients. However, there is lack of research evidence on which to base clinical management in this group of patients. Management decisions often have to be based therefore on extrapolations from other patient cohorts or from younger patients. Data from the European Society for Immunodeficiencies demonstrates that the vast majority of elderly patients suffer from predominantly antibody deficiency syndromes. We review the management of PID disease in the elderly, with a focus on antibody deficiency disease