Monitoring and moderating extreme indoor temperatures in low-income urban communities

Climate change presents significant threats to human health, especially for low-income urban communities in the Global South. Despite numerous studies of heat stress, surprisingly little is known about the temperatures actually encountered by people in their homes, or the benefits of affordable adaptations. This paper examines indoor air temperature measurements gathered from 47 living rooms within eight low-income communities of Accra and Tamale, Ghana. Using multiple temperature indices and a tiered analysis, we evaluate indoor temperature variations linked to roof type, ceiling insulation, presence of fans, and tree shade, for different housing types and locations. Our data reveal indoor temperatures in the range 22.4 ◦C to 45.9 ◦C for Accra, and 22.2 ◦C to 43.0 ◦C in Tamale. Using dummy regression analysis, we find that tree shade reduces the number of very hot days (>40 ◦C) and nights (>30 ◦C) by about 12 and 15 d per year, respectively. Building materials also strongly moderate indoor temperatures but in opposing ways: rooms with traditional mud walls and thatch roofs are on average 4.5 ◦C cooler than rooms in concrete block houses with uninsulated metal roofs during the day but are 1.5 ◦C warmer at night; rooms with ceiling insulation are on average 6.9 ◦C cooler in the day but 1.4 ◦C warmer at night. We conclude that sub-daily data are necessary for reporting extreme indoor temperatures, and that trade-offs between minimum and maximum temperatures require interventions to be assessed carefully before attempting to counter extreme heat inside homes

Microbial Activities and Dissolved Organic Matter Dynamics in Oil-Contaminated Surface Seawater from the Deepwater Horizon Oil Spill Site

The Deepwater Horizon oil spill triggered a complex cascade of microbial responses that reshaped the dynamics of heterotrophic carbon degradation and the turnover of dissolved organic carbon (DOC) in oil contaminated waters. Our results from 21-day laboratory incubations in rotating glass bottles (roller bottles) demonstrate that microbial dynamics and carbon flux in oil-contaminated surface water sampled near the spill site two weeks after the onset of the blowout were greatly affected by activities of microbes associated with macroscopic oil aggregates. Roller bottles with oil-amended water showed rapid formation of oil aggregates that were similar in size and appearance compared to oil aggregates observed in surface waters near the spill site. Oil aggregates that formed in roller bottles were densely colonized by heterotrophic bacteria, exhibiting high rates of enzymatic activity (lipase hydrolysis) indicative of oil degradation. Ambient waters surrounding aggregates also showed enhanced microbial activities not directly associated with primary oil-degradation (β-glucosidase; peptidase), as well as a twofold increase in DOC. Concurrent changes in fluorescence properties of colored dissolved organic matter (CDOM) suggest an increase in oil-derived, aromatic hydrocarbons in the DOC pool. Thus our data indicate that oil aggregates mediate, by two distinct mechanisms, the transfer of hydrocarbons to the deep sea: a microbially-derived flux of oil-derived DOC from sinking oil aggregates into the ambient water column, and rapid sedimentation of the oil aggregates themselves, serving as vehicles for oily particulate matter as well as oil aggregate-associated microbial communities

Experimental Study of the Loosening Phenomenon of an Assembly with Multi Fixations Under Vibration in the Transversal Direction

International audienc

Optimum planting dates for four maturity groups of maize varieties grown in the Guinea savanna zone

Five maize varieties, comprising NAES EE W SR (extra-early, normal maize (NM)), Dorke SR (early, NM), Abeleehi (intermediate, NM), Obatanpa (intermediate, quality protein maize) and Okomasa (late, NM), were sown at 2-week intervals from mid-May to last week of July in 1993 and 1994 at Nyankpala in the Guinea savanna zone. The varieties were assigned to main-plots and planting dates to sub-plots in the randomized complete block with four replications per year. Effects due to variety and planting date were highly significant (P< 0.01) for grain yield. The variety W planting date interaction was not significant for yield. Grain yields averaged over planting dates were 3890, 5252, 5798, 5830, and 5883 kg/ha for the varieties NAES EE W SR, Dorke SR, Abeleehi, Obatanpa and Okomasa, respectively. Grain yields for the six sowing dates averaged over varieties were 5919, 5900, 6232, 4895, 4537 and 4502 kg/ha. Grain yields for the first three planting dates did not differ significantly from each other. Similar results were obtained for the last three planting dates. Yields on the average were 30 per cent higher for the first three planting dates than for the last three. Plant dry matter yield, number of ears per plant and thousand grain weight were the parameters which showed significant positive correlations with grain yield among planting dates. The data showed that (1) for all maturity groups, maize sown from mid-May to mid-June significantly out-yielded the later plantings, (2) the extra-early and early maize varieties were lower yielding than the later varieties, and (3) there was no yield advantage in the late varieties over the intermediate types in the Guinea savanna zone. (Ghana Journal of Agricultural Science, 1997, 30(1): 63-70

Monitoring and moderating extreme indoor temperatures in low-income urban communities

Climate change presents significant threats to human health, especially for low-income urban communities in the Global South. Despite numerous studies of heat stress, surprisingly little is known about the temperatures actually encountered by people in their homes, or the benefits of affordable adaptations. This paper examines indoor air temperature measurements gathered from 47 living rooms within eight low-income communities of Accra and Tamale, Ghana. Using multiple temperature indices and a tiered analysis, we evaluate indoor temperature variations linked to roof type, ceiling insulation, presence of fans, and tree shade, for different housing types and locations. Our data reveal indoor temperatures in the range 22.4 ◦C to 45.9 ◦C for Accra, and 22.2 ◦C to 43.0 ◦C in Tamale. Using dummy regression analysis, we find that tree shade reduces the number of very hot days (>40 ◦C) and nights (>30 ◦C) by about 12 and 15 d per year, respectively. Building materials also strongly moderate indoor temperatures but in opposing ways: rooms with traditional mud walls and thatch roofs are on average 4.5 ◦C cooler than rooms in concrete block houses with uninsulated metal roofs during the day but are 1.5 ◦C warmer at night; rooms with ceiling insulation are on average 6.9 ◦C cooler in the day but 1.4 ◦C warmer at night. We conclude that sub-daily data are necessary for reporting extreme indoor temperatures, and that trade-offs between minimum and maximum temperatures require interventions to be assessed carefully before attempting to counter extreme heat inside homes