Exposure to and experience of self-harm and self-harm related content: an exploratory network analysis

Exposure to the self-harm behaviour of others plays a role in individuals’ own self-harm thoughts and behaviours, but there has been little consideration of the broader range of mediums through which exposure to self-harm related content may occur. N = 477 participants completed an online study, including questions regarding lifetime history of self- harm thoughts and behaviours and the frequency with which they had been exposed to self- harm via various mediums. Gaussian Markov random field network models were estimated using graphical LASSO and extended Bayesian information criterion. Bootstrapping revealed that exposure mediums with a direct connection to self-harm thoughts and behaviours were the internet (rrp = .34, 95% CI [.26, .42]) and in-passing ‘miscellaneous’ exposure (rrp = .14, 95% CI [.00, .23]). However, stability of the network centrality was low (expected influence stability = 0.52). The node with the greatest increase in expected influence within the network was miscellaneous “in-passing” exposure. In-passing exposure is an understudied exposure medium. Our results may suggest new types of exposure mediums for future research. Data were cross-sectional, so temporal relationships between exposure and behaviour could not be determined. Low stability of the networks suggests that future similar studies would benefit from larger sample sizes

Dimensionality-driven spin-flop transition in quasi-one-dimensional PrBa2Cu4O8

In the quasi-one-dimensional cuprate PrBa$_2$Cu$_4$O$_8$, the Pr cations order antiferromagnetically at 17 K in zero field. Through a combination of magnetic susceptibility, torque magnetometry, specific heat and interchain transport measurements, the anisotropic temperature-magnetic field phase diagram associated with this ordering has been mapped out. A low-temperature spin-flop transition in the Pr sub-lattice is found to occur at the same magnetic field strength and orientation as a dimensional crossover in the ground state of the metallic CuO chains. This coincidence suggests that the spin reorientation is driven by a change in the anisotropic Rudermann-Kittel-Kasuya-Yosida (RKKY) interaction induced by a corresponding change in effective dimensionality of the conduction electrons.Comment: 8 pages, 8 figure

Superconducting gap nodes in PrOs_4Sb_12

We examine the superconducting gap nodes in crystals with tetrahedral (T_h) symmetry. The (0,0,1) phase of the three dimensional order parameter in the triplet channel has nodes in the [001] directions. Following a second order phase transition to the state (0,i|eta_2|,|eta_1|), each node lifts away from the Fermi surface and splits into two deep dips. We discuss this scenario in the context of multiple superconducting phases in PrOs4Sb12.Comment: 2 pages, 1 figure, ICM2006, manuscript with higher quality figure may be obtained at http://www.physics.mun.ca/~curnoe/papers/PrOs4Sb12.pd

Phenomenology of the normal state in-plane transport properties of high-TcT_c cuprates

In this article, I review progress towards an understanding of the normal state (in-plane) transport properties of high-$T_c$ cuprates in the light of recent developments in both spectroscopic and transport measurement techniques. Against a backdrop of mounting evidence for anisotropic single-particle lifetimes in cuprate superconductors, new results have emerged that advocate similar momentum dependence in the transport decay rate $\Gamma$({\bf k}). In addition, enhancement of the energy scale (up to the bare bandwidth) over which spectroscopic information on the quasiparticle response can be obtained has led to the discovery of new, unforeseen features that surprisingly, may have a significant bearing on the transport properties at the dc limit. With these two key developments in mind, I consider here whether all the ingredients necessary for a complete phenomenological description of the anomalous normal state transport properties of high-$T_c$ cuprates are now in place.Comment: 31 pages, 10 figure

Non-generality of the Kadowaki-Woods ratio in correlated oxides

An explicit expression for the Kadowaki-Woods ratio in correlated metals is derived by invoking saturation of the (high-frequency) Fermi-liquid scattering rate at the Mott-Ioffe-Regel limit. Significant deviations observed in a number of oxides are quantitatively explained due to variations in carrier density, dimensionality, unit cell volume and the number of individual sheets in the Brillouin zone. A generic re-scaling of the original Kadowaki-Woods plot is also presented.Comment: 9 pages of text, 1 table, 2 figure

Proposed vitamin A supplementation programme for South Africa - design, coverage and cost

Background. A national survey of the micronutrient status of preschool children in South Africa established that vitamin A deficiency is a significant public health problem, requiring urgent attention. A number of immediate and long-term intenrentions were recommended, including the introduction of a vitamin A supplementation programme and a food fortification programme.Objectives. The aim of the study was to assist in the development and implementation of a national vitamin A supplementation programme at primary health care facilities for mothers and children. This was achieved by determining the design, coverage and cost of a national primary health care facility vitamin A supplementation programme.Methods. Based on an extensive review of the literature, the main components of a primary health care facility vitamin A supplementation programme were identified. The annual, recurrent cost of each of the programme component wer estimated for the nine provinces in South Africa. Immunisation coverage rates were used as a proxy for estimating the coverage of the programme.Results. The main components of the programme were identified as: promotion, training, purchase of vitamin A capsules, distribution of vitamin A capsules to primary health care facilities, clistribution of cap ule to the programme beneficiaries, and monitoring and evaluation. The programme would operate from primary health care facililities and would target all children between 6 and 24  months of age and newly delivered mothers. It was estimated that the programme would cover 74% of children and 95% of postpartum women nationally. The total annual, recurrent cost of the national programme was estimated at R16.4 million. The bulk of the costs would include personnel costs, comprising 68% of the total costs. Other costs included promotion (27%), vitamin A capsules (4%) and training (1%). The cost of the programme would vary significantly by province, but the provinces' average total cost per beneficiary would be similar.Conclusion. A primary health care facility vitamin A supplementation programme has been designed and accompanied by an estimated overall cost and coverage for implementation. The findings of the study showed that the programme would be financially feasible and would reach the majority of children under 24 months of age. It is recommended that further research be undertaken to extend the programme to the more 'hard to reach' population using other stategies such as mass immunisation campaigns

Possible co-existence of local itinerancy and global localization in a quasi-one-dimensional conductor

In the chain compound PrBa$_2$Cu$_4$O$_8$ localization appears simultaneously with a dimensional crossover in the electronic ground state when the scattering rate in the chains exceeds the hopping rate between the chains. Here we report the discovery of a large, transverse magnetoresistance in PrBa$_2$Cu$_4$O$_8$ in the localized regime. This result suggests a novel form of localization whereby electrons retain their metallic (quasi-one-dimensional) character over a microscopic length scale despite the fact that macroscopically, they exhibit localized (one-dimensional) behavior.Comment: 4 pages, 4 Figure