Artisanal materials for sustainable construction in developing countries

Sustainable construction is a major challenge to developing countries more so when it comes to the use of artisanal materials in the construction process. This review identifies and examines the challenges facing developing countries in this respect: environmental degradation, poverty, informal settlements, inappropriate regulatory mechanism, inappropriate technology, and neglect in research and development debates. It notes that research and development at local level is necessary for addressing the challenges posed by the use of artisanal materials from sustainable development point of view. Above all, it recommends research into the area of artisanal materials and sustainable construction

Factor analysis of the market environment for artisanal dimension stone in Nairobi, Kenya

Artisanal dimension stone (i.e., blocks cut and shaped from natural rock using hand tools) has attracted scholarly attention as part of the informal sector of the construction industry and as part of the productive enterprise of artisans. One of the areas that intrigue scholars in this respect is the market environment of the subject product. In Nairobi, for instance, researchers have adopted a qualitative approach to the study of the market environment of artisanal dimension stone. We build on the outcomes of previous studies to present a quantitative approach to the factors influencing the market environment of artisanal dimension stone in Kenya by developing the factors identified in the past studies into 24 measurable variables that are then subjected to factor analysis to identify and gauge the principal components. The analysis identifies five principal components that influence the market environment: a difficult marketing terrain, a general lack of specification by building professionals and formal developers, occasional specification by building professionals, a cumbersome stone procurement system, and advantages provided by the use of artisanal dimension stone in building. These include both negative and positive factors, although the negative forces tend to dominate, resulting in an inhibitive rather than a facilitative environment. Recommendations are made to address this situation, including recommendations for an association with Communities and Small-Scale Mining (CASM) (a mining advocacy organisation) or similar institution and the formation of a marketing cooperative by the producing units to help in the formalisation of their transactions

Factor Analysis Of The Market Environment For Artisanal Dimension Stone In Nairobi, Kenya

Artisanal dimension stone (i.e., blocks cut and shaped from natural rock using hand tools) has attracted scholarly attention as part of the informal sector of the construction industry and as part of the productive enterprise of artisans. One of the areas that intrigue scholars in this respect is the market environment of the subject product. In Nairobi, for instance, researchers have adopted a qualitative approach to the study of the market environment of artisanal dimension stone. We build on the outcomes of previous studies to present a quantitative approach to the factors influencing the market environment of artisanal dimension stone in Kenya by developing the factors identified in the past studies into 24 measurable variables that are then subjected to factor analysis to identify and gauge the principal components. The analysis identifies five principal components that influence the market environment: a difficult marketing terrain, a general lack of specification by building professionals and formal developers, occasional specification by building professionals, a cumbersome stone procurement system, and advantages provided by the use of artisanal dimension stone in building. These include both negative and positive factors, although the negative forces tend to dominate, resulting in an inhibitive rather than a facilitative environment. Recommendations are made to address this situation, including recommendations for an association with a mining advocacy organisation such as Communities and Small-Scale Mining (CASM) or similar institution and the formation of a marketing cooperative by the producing units to help in the formalisation of their transactions

Microbial diversity of a disused copper mine site (Parys Mountain, UK), dominated by intensive eukaryotic filamentous growth

The Parys Mountain copper mine (Wales, UK) contains a wide range of discrete environmental microniches with various physicochemical conditions that shape microbial community composition. Our aim was to assess the microbial community in the sediments and overlying water column in an acidic mine drainage (AMD) site containing abundant filamentous biogenic growth via application of a combination of chemical analysis and taxonomic profiling using 16S rRNA gene amplicon sequencing. Our results were then compared to previously studied sites at Parys Mt. Overall, the sediment microbiome showed a dominance of bacteria over archaea, particularly those belonging to Proteobacteria (genera Acidiphilium and Acidisphaera), Acidobacteriota (subgroup 1), Chloroflexota (AD3 cluster), Nitrospirota (Leptospirillum) and the uncultured Planctomycetota/CPIa-3 termite group. Archaea were only present in the sediment in small quantities, being represented by the Terrestrial Miscellaneous Euryarchaeota Group (TMEG), Thermoplasmatales and Ca. Micrarchaeota (Ca. Micracaldota). Bacteria, mostly of the genera Acidiphilium and Leptospirillum, also dominated within the filamentous streamers while archaea were largely absent. This study found pH and dissolved solutes to be the most important parameters correlating with relative proportions of bacteria to archaea in an AMD environment and revealed the abundance patterns of native acidophilic prokaryotes inhabiting Parys Mt sites and their niche specificities

Residential mobility and childhood leukemia.

AimsStudies of environmental exposures and childhood leukemia studies do not usually account for residential mobility. Yet, in addition to being a potential risk factor, mobility can induce selection bias, confounding, or measurement error in such studies. Using data collected for California Powerline Study (CAPS), we attempt to disentangle the effect of mobility.MethodsWe analyzed data from a population-based case-control study of childhood leukemia using cases who were born in California and diagnosed between 1988 and 2008 and birth certificate controls. We used stratified logistic regression, case-only analysis, and propensity-score adjustments to assess predictors of residential mobility between birth and diagnosis, and account for potential confounding due to residential mobility.ResultsChildren who moved tended to be older, lived in housing other than single-family homes, had younger mothers and fewer siblings, and were of lower socioeconomic status. Odds ratios for leukemia among non-movers living <50 meters (m) from a 200+ kilovolt line (OR: 1.62; 95% CI: 0.72-3.65) and for calculated fields ≥ 0.4 microTesla (OR: 1.71; 95% CI: 0.65-4.52) were slightly higher than previously reported overall results. Adjustments for propensity scores based on all variables predictive of mobility, including dwelling type, increased odds ratios for leukemia to 2.61 (95% CI: 1.76-3.86) for living < 50 m from a 200 + kilovolt line and to 1.98 (1.11-3.52) for calculated fields. Individual or propensity-score adjustments for all variables, except dwelling type, did not materially change the estimates of power line exposures on childhood leukemia.ConclusionThe residential mobility of childhood leukemia cases varied by several sociodemographic characteristics, but not by the distance to the nearest power line or calculated magnetic fields. Mobility appears to be an unlikely explanation for the associations observed between power lines exposure and childhood leukemia

Periodic Homogenization and Material Symmetry in Linear Elasticity

Here homogenization theory is used to establish a connection between the symmetries of a periodic elastic structure associated with the microscopic properties of an elastic material and the material symmetries of the effective, macroscopic elasticity tensor. Previous results of this type exist but here more general symmetries on the microscale are considered. Using an explicit example, we show that it is possible for a material to be fully anisotropic on the microscale and yet the symmetry group on the macroscale can contain elements other than plus or minus the identity. Another example demon- strates that not all material symmetries of the macroscopic elastic tensor are generated by symmetries of the periodic elastic structure.Comment: 18 pages, 5 figure

The market environment for artisanal dimension stone in Nairobi, Kenya

This paper reports on a study involving the market environment for artisanal dimension stone in Nairobi, Kenya. Taking the point of view of exchange relationships within a market systems framework it maps out economic interactions involving actors in this market such as suppliers of raw materials, producers, marketers and users of artisanal dimension stone. This strategy enabled the study to understand the enabling environment for the production and use of artisanal dimension stone that is characterized by the following factors: a rising population that sustains the demand for the built environment products, a vibrant construction market, building regulations that favour the use of stone, availability of cheap and abundant unskilled labour and low standards of stone finish involved, availability of natural rock, a regulatory system that can compromise, lack of support by government institutions and an informal system of transaction that is non-compliant with conventional requirements such as labour and environmental laws but ensures ease of entry into the market environment. Such understanding brings potential for rectifying the negative perceptions about this market environment through policy development and change

Breast cancer in patients with germline TP53 pathogenic variants have typical tumour characteristics: the Cohort study of TP53 carrier early onset breast cancer (COPE study)

Germline TP53 pathogenic variants are rare but associated with a high risk of cancer; they are often identified in the context of clinically diagnosed Li-Fraumeni syndrome predisposing to a range of young onset cancers including sarcomas and breast cancer. The study aim was to conduct a detailed morphological review and immuno-phenotyping of breast cancer arising in carriers of a germline TP53 pathogenic variant. We compared breast cancers from five defined groups: (1) TP53 carriers with breast cancer (n = 59), (2) early onset HER2-amplified breast cancer, no germline pathogenic variant in BRCA1/2 or TP53 (n = 55), (3) BRCA1 pathogenic variant carriers (n = 60); (4) BRCA2 pathogenic variant carriers (n = 61) and (5) young onset breast cancer with no known germline pathogenic variant (n = 98). Pathologists assessed a pre-agreed set of morphological characteristics using light microscopy. Immunohistochemistry (IHC) for HER2, ER, PR, p53, integrin alpha v beta 6 (αvβ6) integrin, α-smooth muscle actin (α-SMA) and pSMAD2/3 was performed on tissue microarrays of invasive carcinoma. We confirmed a previously reported high prevalence of HER2-amplified, ductal no special type invasive breast carcinoma amongst known TP53 germline pathogenic variant carriers 20 of 36 (56%). Furthermore we observed a high frequency of densely sclerotic tumour stroma in cancers from TP53 carriers (29/36, 80.6%) when compared with non-carriers, 50.9% (28/55), 34.7% (50/144), 41.4% (65/157), 43.8% (95/217) in groups 2-5 respectively. The majority of germline TP53 gene carrier breast tumours had a high intensity of integrin αvβ6, α-SMA and pSMAD2/3 expression in the majority of cancer cells. In conclusion, aggressive HER2 positive breast cancers with densely sclerotic stroma are common in germline TP53 carriers. High levels of αvβ6 integrin, α-SMA and pSMAD2/3 expression suggest that the dense stromal phenotype may be driven by upregulated transforming growth factor beta signalling.Kate Packwood, Guy Martland, Matthew Sommerlad, Emily Shaw, Karwan Moutasim ... Nicola Poplawski ... et al