Early Experience with Ponseti Club Foot Management in Lagos, Nigeria

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Angular separations of the lensed QSO images

We have analyzed the observed image separations of the gravitationally lensed images of QSOs for a possible correlation with the source redshift. Contrary to the previously noted anti-correlation based on a smaller data set, no correlation is found for the currently available data. We have calculated the average image separations of the lensed QSOs as a function of source redshifts, for isothermal spheres with cores in a flat universe, taking into account the amplification bias caused by lensing. The shape of the distribution of average image separation as a function of redshift is very robust and is insensitive to most model parameters. Observations are found to be roughly consistent with the theoretical results for models which assume the lens distribution to be (i) Schechter luminosity function which, however, can not produce images with large separation and (ii) the mass condensations in a cold dark matter universe, as given by the Press-Schechter theory if an upper limit of 1-7$\times 10^{13}$ M$\odot$ is assumed on the mass of the condensations.Comment: 20 pages, 7 postscript figures, accepted for publication in The Astrophysical Journa

Atomistic Aspects of Diffusion and Growth on the Si and Ge (111) Surfaces

The stability of interfaces and the mechanisms of thin film growth on semiconductors are issues of central importance in electronic devices. These issues can only be understood through detailed study of the relevant microscopic processes. Experimental studies are able to provide detailed, atomic scale information for model systems. Theoretical analysis of experimental results is essential in explaining certain surprising observations and in providing guidance for optimizing conditions and methods of growth. We review recent theoretical work on the diffusion of adatoms, the structure of adsorbate monolayers, and their implications for growth on the Si and Ge (111) surfaces. The theoretical analysis consists of first-principles calculations of the total-energy and entropy factors for stable, metastable and saddle-point configurations. These calculations are supplemented by Monte Carlo simulations of simple models that afford direct contact with experimental observations.Comment: 30 pages, 11 figures (sent upon request, non-standard format

Ram pressure drag - the effects of ram pressure on dark matter and stellar disk dynamics

We investigate the effects of ram pressure stripping on gas-rich disk galaxies in the cluster environment. Ram pressure stripping principally effects the atomic gas in disk galaxies, stripping away outer disk gas to a truncation radius. We demonstrate that the drag force exerted on truncated gas disks is passed to the stellar disk, and surrounding dark matter through their mutual gravity. Using a toy model of ram pressure stripping, we show that this can drag a stellar disk and dark matter cusp off centre within it's dark matter halo by several kiloparsecs. We present a simple analytical description of this process that predicts the drag force strength and its dependency on ram pressures and disk galaxy properties to first order. The motion of the disk can result in temporary deformation of the stellar disk. However we demonstrate that the key source of stellar disk heating is the removal of the gas potential from within the disk. This can result in disk thickening by approximately a factor of two in gas-rich disks.Comment: Accepted by MNRAS (Oct 2011) 17 pages, 11 figures, 1 tabl

Factors Influencing The Practice Of Exclusive Breastfeeding In Three Regions Of Nigeria

Background: Breastfeeding is the super food for babies and is sufficient if given exclusively in the first six months of a baby's life. In Nigeria, the practice of breastfeeding is high but Exclusive Breastfeeding (EBF) rates remain low at 13%. Several interrelating factors directly or indirectly affect the decision or ability of mothers to practice EBF. The objective of this study was to assess the factors influencing EBF in Nigeria.Methodology: A cross sectional survey among 433 mothers of children between six and twenty-four months old was conducted in urban and peri-urban/rural parts of Zaria, Abakaliki, and Ibadan. The study adopted a mixed research methodology that consisted of key informant interviews, structured questionnaires, and focus group discussions. Descriptive statistic was used to analyze the quantitative data while the themes in the qualitative data were analyzed using manual content analysis.Results: Approximately 90% of all mothers interviewed had heard about EBF, although with variations in the exact definition of EBF as many interpreted it to be just till the start of 6 months. The practice of EBF is low - Ibadan (16%), Abakaliki (10%) and Zaria (2%).Inaccurate knowledge of EBF, occupation, antenatal care attendance, age of mothers, supportive environment from stakeholders are some factors associated with the practice of EBF.Conclusion: The findings in this study indicate that several factors affect the practice of EBF in Nigeria. Improving the practice of EBF in the country will require a multifaceted approach and concerted efforts from stakeholders to address the deterring factors limiting its practice.Keywords: Exclusive Breastfeeding, Interrelating factors, social activity and significant others, and Nigeri

Measuring and Modelling the Redshift Evolution of Clustering: the Hubble Deep Field North

(abridged) The evolution of galaxy clustering from z=0 to z=4.5 is analyzed using the angular correlation function and the photometric redshift distribution of galaxies brighter than I_{AB}\le 28.5 in the HDF North. The reliability of the photometric redshift estimates is discussed on the basis of the available spectroscopic redshifts, comparing different codes and investigating the effects of photometric errors. The redshift bins in which the clustering properties are measured are then optimized to take into account the uncertainties of the photometric redshifts. The results show that the comoving correlation length has a small decrease in the range 0<z<1 followed by an increase at higher z. We compare these results with the theoretical predictions of a variety of cosmological models belonging to the general class of CDM. The comparison with the expected mass clustering evolution indicates that the observed high-redshift galaxies are biased tracers of the dark matter with an effective bias b strongly increasing with redshift. Assuming an Einstein-de Sitter universe, we obtain b\simeq 2 at z=2 and b\simeq 5 at z=4. A comparison of the clustering amplitudes that we measured at z=3 with those reported for LBG suggests that the clustering depends on the abundance of the objects: more abundant objects are less clustered, as expected in the paradigm of hierarchical galaxy formation. The strong clustering and high bias measured at z=3 are consistent with the expected density of massive haloes predicted for the various cosmologies here considered. At z=4, the strong clustering observed in the HDF requires a significant fraction of massive haloes to be already formed by that epoch. This feature could be a discriminant test for the cosmological parameters if confirmed by future observations.Comment: 23 pages, Latex using MN style, figures enclosed. Version accepted for publication in MNRA

IL-36 Induces Bisphosphonate-Related Osteonecrosis of the Jaw-Like Lesions in Mice by Inhibiting TGF-β-Mediated Collagen Expression

Long-term administration of nitrogen-containing bisphosphonates can induce detrimental side effects such as bisphosphonate-related osteonecrosis of the jaw (BRONJ) in human. Although inflammation is known to be associated with BRONJ development, the detailed underlying mechanism remains unknown. Here, we report that the pro-inflammatory cytokine IL-36α is, in part, responsible for the BRONJ development. We found a notably higher level of IL-36α and lower level of collagen in the BRONJ lesions in mice. We also found that IL-36α remarkably suppressed TGF-β-mediated expression of Collα1 and α-Sma via the activation of Erk signaling pathway in mouse gingival mesenchymal stem cells. When IL-36 signaling was abrogated in vivo, development of BRONJ lesions was ameliorated in mice. Taken together, we showed the pathologic role of IL-36α in BRONJ development by inhibiting collagen expression and demonstrated that IL-36α could be a potential marker and a therapeutic target for the prevention and treatment of BRONJ