Acceptability – a neglected dimension of access to health care : findings from a study on childhood convulsions in rural Tanzania

ABSTRACT: BACKGROUND: Acceptability is a poorly conceptualized dimension of access to health care. Using a study on childhood convulsion in rural Tanzania, we examined social acceptability from a user perspective. The study design is based on the premise that a match between health providers' and clients' understanding of disease is an important dimension of social acceptability, especially in trans-cultural communication, for example if childhood convulsions are not linked with malaria and local treatment practices are mostly preferred. The study was linked to health interventions with the objective of bridging the gap between local and biomedical understanding of convulsions. METHODS: The study combined classical ethnography with the cultural epidemiology approach using EMIC (Explanatory Model Interview Catalogue) tool. EMIC interviews were conducted in a 2007/08 convulsion study (n = 88) and results were compared with those of an earlier 2004/06 convulsion study (n = 135). Earlier studies on convulsion in the area were also examined to explore longer-term changes in treatment practices. RESULTS: The match between local and biomedical understanding of convulsions was already high in the 2004/06 study. Specific improvements were noted in form of (1) 46% point increase among those who reported use of mosquito nets to prevent convulsion (2) 13% point decrease among caregivers who associated convulsion with 'evil eye and sorcery', 3) 14% point increase in prompt use of health facility and 4)16% point decrease among those who did not use health facility at all. Such changes can be partly attributed to interventions which explicitly aimed at increasing the match between local and biomedical understanding of malaria. Caregivers, mostly mothers, did not seek advice on where to take an ill child. This indicates that treatment at health facility has become socially acceptable for severe febrile with convulsion. CONCLUSION: As an important dimension of access to health care 'social acceptability' seems relevant in studying illnesses that are perceived not to belong to the biomedical field, specifically in trans-cultural societies. Understanding the match between local and biomedical understanding of disease is fundamental to ensure acceptability of health care services, successful control and management of health problems. Our study noted some positive changes in community knowledge and management of convulsion episodes, changes which might be accredited to extensive health education campaigns in the study area. On the other hand it is difficult to make inference out of the findings as a result of small sample size involved. In return, it is clear that well ingrained traditional beliefs can be modified with communication campaigns, provided that this change resonates with the beneficiaries

Effect of disorder on the vortex-lattice melting transition

We use a three dimensional stacked triangular network of Josephson junctions as a model for the study of vortex structure in the mixed state of high Tc superconductors. We show that the addition of disorder destroys the first order melting transition occurring for clean samples. The melting transition splits in two different (continuous) transitions, ocurring at temperatures Ti and Tp (>Ti). At Ti the perpendicular-to-field superconductivity is lost, and at Tp the parallel-to-field superconductivity is lost. These results agree well with recent experiments in YBaCuO.Comment: 4 pages + 2 figure

Vortex-line liquid phases: Longitudinal superconductivity in the lattice London model

We study the vortex-line lattice and liquid phases of a clean type-II superconductor by means of Monte Carlo simulations of the lattice London model. Motivated by a recent controversy regarding the presence, within this model, of a vortex-liquid regime with longitudinal superconducting coherence over long length scales, we directly compare two different ways to calculate the longitudinal coherence. For an isotropic superconductor, we interpret our results in terms of a temperature regime within the liquid phase in which longitudinal superconducting coherence extends over length scales larger than the system thickness studied. We note that this regime disappears in the moderately anisotropic case due to a proliferation, close to the flux-line lattice melting temperature, of vortex loops between the layers.Comment: 8 pages, Revtex, with eps figures. To appear in Phys. Rev.

Stability of the vortex lattice in a rotating superfluid

We analyze the stability of the vortex lattice in a rotating superfluid against thermal fluctuations associated with the long-wavelength Tkachenko modes of the lattice. Inclusion of only the two-dimensional modes leads formally to instability in infinite lattices; however, when the full three-dimensional spectrum of modes is taken into account, the thermally-induced lattice displacements are indeed finite.Comment: 16 page

First-Order Vortex Lattice Melting and Magnetization of YBa2_2Cu3_3O$_{7-\delta}

We present the first non-mean-field calculation of the magnetization $M(T)$ of YBa$_2$Cu$_3$O$_{7-\delta}$ both above and below the flux-lattice melting temperature $T_m(H)$. The results are in good agreement with experiment as a function of transverse applied field $H$. The effects of fluctuations in both order parameter $\psi({\bf r})$ and magnetic induction $B$ are included in the Ginzburg-Landau free energy functional: $\psi({\bf r})$ fluctuates within the lowest Landau level in each layer, while $B$ fluctuates uniformly according to the appropriate Boltzmann factor. The second derivative $(\partial^2 M/\partial T^2)_H$ is predicted to be negative throughout the vortex liquid state and positive in the solid state. The discontinuities in entropy and magnetization at melting are calculated to be $\sim 0.034\, k_B$ per flux line per layer and $\sim 0.0014$~emu~cm$^{-3}$ at a field of 50 kOe.Comment: 11 pages, 4 PostScript figures in one uuencoded fil

Vortices and 2D bosons: A Path-Integral Monte Carlo Study

The vortex system in a high-T_c superconductor has been studied numerically using the mapping to 2D bosons and the path-integral Monte Carlo method. We find a single first-order transition from an Abrikosov lattice to an entangled vortex liquid. The transition is characterized by an entropy jump dS = 0.4 k_B per vortex and layer (parameters for YBCO) and a Lindemann number c_L = 0.25. The increase in density at melting is given by d\rho = 6.0*10^{-4} / \lambda(T)^2. The vortex liquid corresponds to a bosonic superfluid, with \rho_s = \rho even in the limit \lambda -> \infty.Comment: 9 pages, RevTeX, 4 PostScript figures. The entropy jump at the transition has been recomputed and is now in agreement with experiments on YBCO. Some minor modifications were made in the tex

First-Order Melting of a Moving Vortex Lattice: Effects of Disorder

We study the melting of a moving vortex lattice through numerical simulations with the current driven 3D XY model with disorder. We find that there is a first-order phase transition even for large disorder when the corresponding equilibrium transition is continuous. The low temperature phase is an anisotropic moving glass.Comment: Important changes from original version. Finite size analysis of results has been added. Figure 2 has been changed. There is a new additional Figure. To be published in Physical Review Letter

Monte-Carlo calculation of longitudinal and transverse resistivities in a model Type-II superconductor

We study the effect of a transport current on the vortex-line lattice in isotropic type-II superconductors in the presence of strong thermal fluctuations by means of 'driven-diffusion' Monte Carlo simulations of a discretized London theory with finite magnetic penetration depth. We calculate the current-voltage (I-V) characteristics for various temperatures, for transverse as well as longitudinal currents I. From these characteristics, we estimate the linear resistivities R_xx=R_yy and R_zz and compare these with equilibrium results for the vortex-lattice structure factor and the helicity moduli. From this comparison a consistent picture arises, in which the melting of the flux-line lattice occurs in two stages for the system size considered. In the first stage of the melting, at a temperature T_m, the structure factor drops to zero and R_xx becomes finite. For a higher temperature T_z, the second stage takes place, in which the longitudinal superconducting coherence is lost, and R_zz becomes finite as well. We compare our results with related recent numerical work and experiments on cuprate superconductors.Comment: 4 pages, with eps figure

Charge-order transition in the extended Hubbard model on a two-leg ladder

We investigate the charge-order transition at zero temperature in a two-leg Hubbard ladder with additional nearest-neighbor Coulomb repulsion V using the Density Matrix Renormalization Group technique. We consider electron densities between quarter and half filling. For quarter filling and U=8t, we find evidence for a continuous phase transition between a homogeneous state at small V and a broken-symmetry state with "checkerboard" [wavevector Q=(pi,pi)] charge order at large V. This transition to a checkerboard charge-ordered state remains present at all larger fillings, but becomes discontinuous at sufficiently large filling. We discuss the influence of U/t on the transition and estimate the position of the tricritical points.Comment: 4 pages, 5 figs, minor changes, accepted for publication in PRB R