Impact Of Local Variations Research Articles

The impact of local variations in a temperate maritime climate on building energy use

ABSTRACTWe investigate the impact of local climatic variations on the energy performance of buildings by conducting simulations using weather files generated from high-resolution measurements covering 33 stations within a 77 km2 area in southern Vancouver Island, British Columbia, Canada. Weather files were created by resampling the data and applying appropriate models to obtain unmeasured values. The difference in microclimate has been analysed statistically and graphically; average annual temperature varies by around 1°C, and at certain times there is a 6°C variation across the (very small) region.Building energy simulations of a small naturally ventilated office building and a larger air-conditioned building were performed using EnergyPlus for all weather files. Significant variation is found spatially and temporally which would have substantial implications for building design and energy use. The variation in annual heating energy use is ±5% of the mean, equivalent to 18 kWh/m2/a, with even greater relative variation in cooling energy use.

Geographical Patterns of HIV Sero-Discordancy in High HIV Prevalence Countries in Sub-Saharan Africa.

Introduction: Variation in the proportion of individuals living in a stable HIV sero-discordant partnership (SDP), and the potential drivers of such variability across sub Saharan Africa (SSA), are still not well-understood. This study aimed to examine the spatial clustering of HIV sero-discordancy, and the impact of local variation in HIV prevalence on patterns of sero-discordancy in high HIV prevalence countries in SSA. Methods: We described the spatial patterns of sero-discordancy among stable couples by analyzing Demographic and Health Survey data from Cameroon, Kenya, Lesotho, Tanzania, Malawi, Zambia, and Zimbabwe. We identified spatial clusters of SDPs in each country through a Kulldorff spatial scan statistics analysis. After a geographical cluster was identified, epidemiologic measures of sero-discordancy were calculated and analyzed. Results: Spatial clusters with significantly high numbers of SDPs were identified and characterized in Kenya, Malawi, and Tanzania, and they largely overlapped with the clusters with high HIV prevalence. There was a positive correlation between HIV prevalence and the proportion of SDPs among all stable couples across within and outside clusters. Conversely, there was a negative, but weak and not significant, correlation between HIV prevalence and the proportion of SDPs among all stable couples with at least one HIV-infected individual in the partnership. Discussion: There does not appear to be distinct spatial patterns for HIV sero-discordancy that are independent of HIV prevalence patterns. The variation of the sero-discordancy measures with HIV prevalence across clusters and outside clusters demonstrated similar patterns to those observed at the national level. The spatial variable does not appear to be a fundamental nor independent determinant of the observed patterns of sero-discordancy in high HIV prevalence countries in SSA.

The effect of local variation in malaria transmission on the prevalence of sulfadoxine-pyrimethamine resistant haplotypes and selective sweep characteristics in Malawi.

BackgroundPersistence of sulfadoxine–pyrimethamine (SP) resistance has been described in an urban setting in Malawi where malaria transmission is relatively low. Higher malaria transmission is associated with greater genetic diversity and more frequent genetic recombination, which could lead to a more rapid re-emergence of SP-sensitive parasites, as well as more rapid degradation of selective sweeps. In this study, the impact of local variation in malaria transmission on the prevalence of SP-resistant haplotypes and selective sweep characteristics was investigated at an urban site with low parasite prevalence and two rural sites with moderate and high parasite prevalence.MethodsSamples from three sites with different parasite prevalence were genotyped for resistance markers within pfdhfr-ts and pfdhps and at microsatellites flanking these genes. Expected heterozygosity (He) was estimated to evaluate genetic diversity.ResultsNo difference in the prevalence of highly resistant DHFR 51I/59R/108N and DHPS 437G/540E was found between sites. Small differences in He flanking pfdhfr-ts and pfdhps were seen between rural-moderate and the other sites, as well as some shared haplotypes between the rural-high and urban-low sites.ConclusionsThe results do not show an effect of local variation in malaria transmission, as inferred from parasite prevalence, on SP-resistant haplotype prevalence.Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-015-0860-7) contains supplementary material, which is available to authorized users.

Hospital staffing and local pay: an investigation into the impact of local variations in the competitiveness of nurses' pay on the staffing of hospitals in France.

Spatial wage theory suggests that employers in different regions may offer different pay rates to reflect local amenities and cost of living. Higher wages may be required to compensate for a less pleasant environment or a higher cost of living. If wages in a competing sector within an area are less flexible and therefore less competitive this may lead to an inability to employ staff. This paper considers the market for nursing staff in France where there is general regulation of wages and public hospitals compete for staff with the private hospital and non-hospital sectors. We consider two types of nursing staff, registered and assistant nurses and first establish the degree of spatial variation in the competitiveness of pay of nurses in public hospitals. We then consider whether these spatial variations are associated with variation in the employment of nursing staff. We find that despite regulation of pay in the public and private sector, there are substantial local variations in the competitiveness of nurses' pay. We find evidence that the spatial variations in the competitiveness of pay are associated with relative numbers of assistant nurses but not registered nurses. While we find the influence of the competitiveness of pay is small, it suggests that nonpay conditions may be an important factor in adjusting the labour market as might be expected in such a regulated market.

Impact of local variation in coating structure on uniformity in print gloss

Point-to-point variation in the gloss of a print has been reported to be one of the most visually disturbing aspects of a printed paper. This work sought to determine the effect of pigment and binder content on the coating structure, surface properties, and print gloss variations occurring in a printed offset paper. The results from a pilot coating and full-scale sheet-fed offset printing trial are reported, with special emphasis on uniformity in print gloss. The effect of calendering and print impression also was considered. Uniformity in print was analyzed in terms of print gloss variation (PGV) in the heavily inked areas. Calendering and point-to-point variation in coating porosity had a significant effect on PGV. The observed nonuniformity in print is discussed in terms of local variations in coating porosity and local variation in coating micro-roughness. Under the conditions investigated, uniformity in surface porosity decreased with increasing latex content, but increased with clay content.

Fracture mechanical character of small cracks in polycrystalline materials: concept and numerical K calculations

The impact of local variations in elastic modulus on the fracture mechanical character of “microstructurally small” cracks commonly encountered in early stages of fatigue in polycrystalline materials, is assessed. In particular, the stress intensity factor (SIF), K, variations along the crack front, influenced by the random crystallographic orientations of grains were numerically calculated for random variations of elastic moduli of grains. A conceptual framework for calculating the K variations due to local anisotropy was established on the basis of the weight function technique for three-dimensional cracks. As a model, an elliptical crack having sizes: three, five and twenty times the grain size, in polycrystalline Ni, Fe and Ti, was considered. Using patterns of random crystallographic orientations of grains, local inhomogeneous stresses that existed over the crack faces were determined on the basis of isostrain condition. These inhomogeneous stresses were used in the weight function-based calculations, to evaluate the effect of these stresses on the K variation along the crack front. It is shown that the effect of local anisotropy on the K variation is significant at small crack sizes and that the fracture mechanical character of microstructurally small cracks is quite different from that of large cracks in the isotropic environment. It is suggested that the local deviations in shapes of microstructurally small cracks, experimentally observed in many materials, are connected to the local K variations and their dependence on crack size, relative to the grain size.