The spectrum of neutrons at 60 hg m(-2)

The rate of neutron interactions was measured for the energy range 7.5 to 60 MeV, using a 3.85 kg cell of liquid scintillator. The neutrons are selected by pulse shape discrimination, with anticoincidence counters used to reduce interference from muons transversing the scintillator. The observed flux is interpreted in terms of neutrons produced from environmental uranium and thorium, those resulting from the capture of negative muons in nuclei and those from fast muon interactions

Mg II Absorption Characteristics of a Volume-Limited Sample of Galaxies at z ~ 0.1

We present an initial survey of Mg II absorption characteristics in the halos of a carefully constructed, volume-limited subsample of galaxies embedded in the spectroscopic part of the Sloan Digital Sky Survey. We observed quasars near sightlines to 20 low-redshift (z ~ 0.1), luminous M_r <= -20.5 galaxies in SDSS DR4 and DR6 with the LRIS-B spectrograph on the Keck I telescope. The primary systematic criteria for the targeted galaxies are a redshift z >~ 0.1 and the presence of an appropriate bright background quasar within a projected 75 kpc/h of its center, although we preferentially sample galaxies with lower impact parameters and slightly more star formation within this range. Of the observed systems, six exhibit strong [EW(2796) >= 0.3 Ang.] Mg II absorption at the galaxy's redshift, six systems have upper limits which preclude strong Mg II absorption, while the remaining observations rule out very strong [EW(2796) >= 1-2 Ang] absorption. The absorbers fall at higher impact parameters than many non-absorber sightlines, indicating a covering fraction f_c = 0.3-Angstrom absorbers at z ~ 0.1, even at impact parameters <= 35 kpc/h (f_c ~ 0.25). The data are consistent with a possible dependence of covering fraction and/or absorption halo size on the environment or star-forming properties of the central galaxy.Comment: accepted for publication in A

Progressive (dis)ability: the experience of living with Charcot-Marie-Tooth disease

This thesis is an Interpretative Phenomenological Analysis of the experiences of six women living with Charcot-Marie-Tooth (CMT), an inherited degenerative neurological condition with a range of debilitating symptoms. It is the first ever in-depth qualitative study into the lived experience of CMT, which is relatively common yet largely unknown. This is “Paradigm II” disability research (Olkin, 1999) that listens to the voices of those with disabilities to advocate for improved conditions, services and status in the world. Those who are disabled are empowered to speak for themselves. The researcher, too, has CMT and another progressive neurological condition, Parkinson’s. The women’s stories are analysed alongside his own autobiographical narrative. Four themes are identified and discussed, drawing on literature from across the fields of psychology, psychotherapy and disability studies: loss, discrimination, identity and growth. Arising from these findings, the concept of “disability apartheid” is developed into a “two worlds” model which can be used to describe how psychological factors such as acceptance and shame can impact the ways in which those with disability identify and engage with a disabling world and with their own lives. The researcher argues for “one world” where all individual capabilities and limitations are respected. The findings also inform 12 clinical recommendations for counselling psychologists, psychotherapists or other healthcare professionals working with CMT, other neurological or progressive physical conditions, or disability

The development of self-injury as a multi-functional behaviour

In order to advance our understanding of self-injury this longitudinal study investigated the experiences of 25 adults who had used or were using self-injury. This was achieved by obtaining verbal narrative accounts of their experiences of using self-injury from its onset during childhood or early adolescence, throughout adolescence and into adulthood. These verbatim accounts formed a corpus of data which was analysed using a grounded theory method. This process established seven robust categories associated with the use of self-injury consisting of behavioural, cognitive, emotional, social, occupational, communication and physiological experiences. By thoroughly examining these categories the development of self-injury as a versatile multi-functional behaviour emerged which was governed by the individuals‟ needs. Evidence for these multiple uses stemmed from the similarities that developed in the individuals‟ use of self-injury over time. Highlighting these multiple functions it was established that improved social, communication and occupational conditions were crucial aspects in the participants‟ reduction in using self-injury. The contribution this research has made towards developing our understanding of self-injury was addressed, particularly in relation to its use by the non-clinically defined members of the general public who took part, and in the context of advancing relevant nursing research and practice. Several critical aspects of the methodology were identified, in particular the restrictive generalisation of the findings to others who self-injure, and the use of retrospective accounts were discussed and directives were outlined to improve these aspects in future research. Proposals were made for further research to clarify and investigate the multiple functions of self-injury and to increase our understanding of the continuing use of covert self-injury during adulthood. Additionally, the relevance of the findings to nursing practice, principally in relation to adequately assessing the use of self-injury was discussed

Contributions of Vacuum and Plasmon Modes to the Force on a Small Sphere near a Plate

The force on a small sphere with a plasma model dielectric function and in the presence of a perfectly reflecting plane is considered. The contribution of both the vacuum modes of the quantized electromagnetic field and of plasmon modes in the sphere are discussed. In the case that the plasmon modes are in their ground state, quasi-oscillatory terms from the vacuum and plasmon parts cancel one another, leading a monotonic attractive force. If the plasmon modes are not in the ground state, the net force is quasi-oscillatory. In both cases, the sphere behaves in the same way as does an atom in either its ground state or an excited state.Comment: 7 pages, no figures, talk presented at "Quantum Fields under External Conditions - 2005", Barcelona, Spain, September 200

Electrical and magnetic properties of the complete solid solution series between SrRuO3 and LaRhO3: Filling t2g versus tilting

A complete solid solution series between the t2g^4 perovskite ferromagnet SrRuO3 and the diamagnetic t2g^6 perovskite LaRhO3 has been prepared. The evolution with composition x in (SrRuO3)(1-x)(LaRhO3)(x) of the crystal structure and electrical and magnetic properties has been studied and is reported here. As x increases, the octahedral tilt angle gradually increases, along with the pseudocubic lattice parameter and unit cell volume. Electrical resistivity measurements reveal a compositionally driven metal to insulator transition between x = 0.1 and 0.2. Ferromagnetic ordering gives over to glassy magnetism for x > 0.3 and no magnetic ordering is found above 2 K for x > 0.5. M_sat and Theta_CW decrease with increasing x and remain constant after x = 0.5. The magnetism appears poised between localized and itinerant behavior, and becomes more localized with increasing x as evidenced by the evolution of the Rhodes-Wohlfarth ratio. mu_eff per Ru is equal to the quenched spin-only S value across the entire solid solution. Comparisons with Sr(1-x)Ca(x)RuO3 reinforce the important role of structural distortions in determining magnetic ground state. It is suggested that electrical transport and magnetic properties are not strongly coupled in this system

Renormalization group analysis of the Reynolds stress transport equation

The pressure velocity correlation and return to isotropy term in the Reynolds stress transport equation are analyzed using the Yakhot-Orszag renormalization group. The perturbation series for the relevant correlations, evaluated to lowest order in the epsilon-expansion of the Yakhot-Orszag theory, are infinite series in tensor product powers of the mean velocity gradient and its transpose. Formal lowest order Pade approximations to the sums of these series produce a fast pressure strain model of the form proposed by Launder, Reece, and Rodi, and a return to isotropy model of the form proposed by Rotta. In both cases, the model constant are computed theoretically. The predicted Reynolds stress ratios in simple shear flows are evaluated and compared with experimental data. The possibility is discussed of driving higher order nonlinear models by approximating the sums more accurately