Farm income, gender differentials and climate risk in Cameroon: typology of male and female adaptation options across agroecologies

This paper explores the response to risk of smallholder agricultural producers in the face of variable and changing climate in Cameroon. The low rainfall distribution in some regions of the country and the high inter-seasonal variability of rainfall makes crop production, on which the livelihood of rural inhabitants is based, a risky enterprise. Women farmers in Cameroon are an important group for whom risk aversion influences production outcomes and welfare. This study identifies and analyses the effect of climate risks on the productive activities and the management options of male and female farmers. Women-owned farms, on average, record profits of US620 per hectare to about US 620 per hectare to about US 935 for crop enterprises across the different agroecological zones. Comparatively static results indicate that increases in climate variability and the uncertainty of climate conditions have an explicit impact on farm profit. The impacts of increased uncertainty in climate and risk aversion are ambiguous depending on the agroecology. Ex-ante and ex-post risk management options reveal that female-owned farms in the northern Sahel savannah zone rely on more sophisticated strategies to reduce the impact of shocks. While adapting to uncertain climate positively influences profit levels, risk measured as the variance of rainfall or temperature per unit variation in profit is significant. This analysis stresses the increased importance of climate risk management as a prelude to the panoply of adaptation choice in response to expected climatic change.     

Appraisal of the groundwater balance components from multi-remote sensing datasets in a semi-arid region

Semi-arid regions across the globe are fronting water crises, signaling a challenge to ensure future water security. Given the high inter-seasonal rainfall variability and unrestrained groundwater extraction, the precise quantification of groundwater flow components in an aquifer system is a priority. To address this challenge, we used high-resolution remote sensing (RS) data (Landsat and IRS) and GIS modeling (SEBAL, ArcCN) to spatially quantify major groundwater balance (GWB) components, viz., evapotranspiration (ET), rainfall recharge (R), surface runoff (Q), groundwater extraction (PG), irrigation return flow (IRF), and ultimately changes in groundwater storage (ΔS) in a small semi-arid crystalline representative watershed. Results show that a total of ~?230 mm of groundwater is extracted during 2008–2009, creating a negative impact on the groundwater resource, which is further enhanced by limited recharge and high ET. A decrease of approximately 65 mm in groundwater storage is observed in a single hydrological year, and given a very low specific yield, this decrease will introduce large water level decline. The study establishes that declining groundwater level in the watershed is a direct result of over-extraction, and owing to this scenario, efficient irrigation and land use policies are suggested as potential approaches to minimize extraction specifically in the dry season. Our methodology provides a systematic assessment of vital GWB components at a high spatial resolution and an insight on various sustainable mitigation methods. This methodology is useful in the planning and management of groundwater resources, particularly in water-stressed areas.     

Influence of metallic species for efficient photocatalytic water disinfection: bactericidal mechanism of in vitro results using docking simulation

Environmental Science and Pollution Research - TiO2-based heterogeneous photocatalysis systems have been reported with remarkable efficiency to decontaminate and mineralize a range of pollutants...     

Organochlorine pesticides in the surrounding soils of POPs destruction facility: source fingerprinting,human health,and ecological risks assessment

Environmental Science and Pollution Research - The elimination of persistent organic pollutants (POPs) obsolete pesticides stockpiles, particularly the organochlorine pesticides (OCPs), is one of...     

Reproduction, larval growth, and reproductive development in African clawed frogs (Xenopus laevis) exposed to atrazine

Reproductive success and development of F2 offspring from F1 adult African clawed frogs (Xenopus laevis) exposed to atrazine throughout larval development and as sexually mature adults was examined. Larval X. laevis were exposed to one of four nominal concentrations of atrazine (0, 1, 10, 25 microg atrazine/l) beginning 96 hr after fertilization and continuing through two years post-metamorphosis. Clutch size and survival of offspring were used as measurement endpoints to gauge reproductive success of the F1 frogs. Larval survivorship and time to metamorphosis were used to gauge developmental success of the F2 offspring from atrazine-exposed frogs. Testes in F1 and F2 frogs were examined for incidence of anomalies, such as testicular ovarian follicles, and sex ratios in F2 offspring were investigated to determine if exposure to atrazine caused trans-generational effects (effects on F2 individuals due to exposure of F1 individuals). There were no effects of any of the studied concentrations of atrazine on clutch size of F1 frogs. There were also no effects on hatching success or time to metamorphosis. Sex ratios did not differ between F2 offspring among treatments. There was no evidence to suggest a transgenerational effect of atrazine on spawning success or reproductive development of X. laevis. This is consistent with the presence of robust populations of X. laevis in areas where they are exposed to atrazine that has been used for several decades for weed control in production of corn. Our observations also are consistent with the results of most other studies of frogs where no effects were found to be associated with exposure to atrazine. Our data do not support the hypothesis that atrazine significantly affects reproductive fitness and development of frogs.     

Comparison of constant volume balloons, model trajectories and tracer transport during ETEX

In the field phases of the European Tracer EXperiment (ETEX), an inert tracer was released for 12 h into the atmosphere and samples taken at several locations downwind. During the same time, several Constant Volume Balloons (CVB) (10 and 6 for ETEX first and second release, respectively) were launched into different altitudes and followed as far as 21–188 km, to indicate the initial dispersion directions of the tracer puff. A model simulating the CVB behaviour in hydrostatic meso-scale model forecasts is applied to ETEX data to demonstrate its capability to predict the tracer puff mean axis over long distances (−2000 km). CVB model results are first compared to air parcels trajectories and 2D (i.e. isentropic, isobaric and isodensity) trajectories. Then they are compared to the measured CVB trajectories and finally to the tracer puff trajectories. As expected, the CVB model and isodensity model trajectories are found to be identical. The 16 CVBs calculated trajectories nearly overlap the real ones over 21–188 km with mean absolute horizontal transport deviations less than 20 km (average value of 8.2 km). The corresponding relative transport deviations are less than 45% with an average value of 20.6%. Better predictions are obtained for the ETEX second release. During the 60 h following ETEX’s first release start, the simulated CVBs are mainly found in the area of the maximum surface concentrations of the released tracer, up to 2000 km. Up to 36 h after ETEX second tracer release start, the simulated CVB trajectories predict well the mean axis of the tracer puff, but failed later.     

Challenges of textile waste composite products and its prospects of recycling

Journal of Material Cycles and Waste Management - Every year, a massive volume of textile waste is disposed of in a landfill or incinerated, contributing to resource loss and environmental...     

Reactions between aqueous zinc,aluminium and iron with increasing solutionpH

Solutions of zinc, aluminium and/or iron, as chlorides in NaCl of ionic strength 0.13 mol/l atpH 3, were mixed to give initial concentrations of 0–5, 5–50 and 10–100 g/ml, respectively. Sodium hydroxide was then added to increase thepH in a range up to 7. Turbidity was measured and equilibrium concentrations were determined after filtration (< 0.1 m). Decrease inpH on mixing suggested an immediate reaction, with the release of protons. At allpH values Zn concentration decreased with increasing initiai concentrations of Fe and Al. Adsorption and/or nucleation of Zn with Fe and Al was highlypH dependent and increased markediy with increasingpH. The particle size of the products increased with increasingpH and initial concentration of the elements. Increasing Al concentration decreased the size of Fe nucleates at a given Fe concentration. The results suggest that co-precipitation may be involved as well as adsorption. This has important consequences for the availability of Zn to plants, especially in Zn-deficient soils, and is of relevance to the products of mixing acid drainage waters with streams and lakes.     

Evaluation of chlordimeform and degradation products for mutagenic and DNA-damaging activity in Salmonella typhimurium and Escherichia coli

The mutagenic activity of chlordimeform and two of its breakdown products, 4-chloro-o-toludine and 4-chloro-N-formyl-o-toluidine were determined with five histidine dependent strains of Salmonella typhimurium (TA1535, TA1537, TA1538, TA98, TA100) and five tryptophan dependent strains of E. coli WP2 (WP2, WP2uvrA, WP67, CM611, CM571) with and without rat liver microsomal enzymes. 4-chloro-o-toluidine increased the number of the reversions of the S. typhimurium strain TA1535 more than two fold over spontaneous at the concentration of 400 micrograms/plate. The results of the DNA repair tests in the Salmonella TA1538/TA1978 and E. coli multirepair deficient systems showed that both breakdown products were active in inducing damage not repaired in at least one repair deficient strain while chlordimeform itself was inactive.