Evaluation of protective effects of sulforaphane on DNA damage caused by exposure to low levels of pesticide mixture using comet assay

The objective of the study was to evaluate the potential risk of DNA damage due to exposure to a mixture of the most widely used pesticides, namely endosulfan, chlorpyriphos and thiram at an environmentally relevant concentration (5 μM each) and the DNA protective capacity of sulforaphane (SFN) (10–30 μg/mL). DNA damage in human lymphocytes was ascertained with Single Cell Gel Electrophoresis (SCGE), also called Comet Assay. For positive control, H₂O₂ at 100 mM was used. The pesticide mixture produced DNA damage at the concentration used in the lymphocytes. SFN was able to offer a statistically significant (P < 0.01), concentration-dependant protection to DNA damage between 10–20 μg/mL in both the pre-incubation and co-incubation strategies. The results indicate that exposure to low levels of these pesticide mixtures can induce DNA damage, and the presence of SFN in diet may reduce the incidence of genetic damage, especially in farm workers. However, it is not clear whether SFN is involved in quenching of the free radicals generated by the pesticide mixture or it is involved in DNA repair mechanism.     

Cadmium stress alters gene expression of DNA mismatch repair related genes in Arabidopsis seedlings

Cadmium (Cd) is a non essential element, and is a widespread environmental pollutant. Exposure to Cd can result in a variety of adverse health effects in plant and humans. In the current study, Arabidopsis seedlings were used as a bio-indicator of Cd pollution. Seedlings were grown on MS media containing 0-6.0 mg L(-1) Cd for 18 days, and the gene expression patterns were used to link increased Cd exposure with progressive biological effects. Reduction of total soluble protein content in shoots of the Arabidopsis seedlings occurred with increase in Cd concentrations. For the gene expression patterns, seven genes known to be involved in cell division and DNA mismatch repair (MMR) system were investigated by semi-quantitative RT-PCR, and normalized using 18S rRNA gene expression. Expression of the proliferating cell nuclear antigen 2 (atPCNA 2), MutS 3 homolog (atMSH 3) and MutL1 homolog (atMLH1) genes in shoots of Arabidopsis was strongly induced by exposure to 0.75 mg L(-1) Cd, but were repressed by other Cd concentrations whereas exposure to 0.75-6 mg L(-1) of Cd resulted in a decreased expression of atPCNA1, atMSH 2, 6 and 7 genes independently of any observable biological effects, including survival, fresh weight and chlorophyll level of shoots. This work demonstrated that specific gene expression changes could serve as useful molecular biomarkers indicative of Cd exposure and related biological effects.     

SOME GEOMORPHIC RELATIONSHIPS AND HYDROGRAPH ANALYSIS1

ABSTRACT: First order drainage channels originate when the tractive force exerted by flowing water is sufficient to move surface sediment. The amount of runoff available to move sediment is a function of geologic and climatic characteristics. An experimental analysis showed that soils derived from fine grained rocks had lower infiltration rates and higher runoff volume than soils derived from coarser grained rocks in a semi-arid climate. Root density and penetration increased in a more humid climate and increased infiltration rates. The number of first order channels was inversely proportional to the infiltration capacity of the soil. Each first order channel acts as a source area for surface runoff. The distribution of first order channel distances from the gage determines the timing of the delivery of water to the gage. A comparison of the frequency histogram of first order channel distances for drainage basins in Pennsylvania and their hydxographs of runoff from general storms showed marked similarity. This close correspondence indicated the shape of the surface runoff hydrograph and was largely controlled by the distribution of first order channel distances.     

Some effects of teenagers' part-time employment: The quantity and quality of work make the difference

We investigated the associations of the quantity and quality of part-time employment with the school performance (amount of class cutting, homework, and average grades) and personal functioning (self-esteem and time use) of high-school students. Two hypotheses were tested: (a) working long hours would be associated with detrimental effects, but (b) the quality of employment would moderate these effects, such that employment quantity would be associated with detrimental effects only for low quality jobs. Data from 563 high school students (n = 233 in part-time employment) provided support for the hypotheses. Conceptual, practical and policy ramifications of these findings are considered.     

Enhanced learning from multi-stakeholder partnerships: Lessons from the Enabling Rural Innovation in Africa programme

Despite increasing interest and support for multi‐stakeholder partnerships, empirical applications of participatory evaluation approaches to enhance learning from partnerships are either uncommon or undocumented. This paper draws lessons on the use of participatory self‐reflective approaches that facilitate structured learning on processes and outcomes of partnerships. Such practice is important to building partnerships, because it helps partners understand how they can develop more collaborative and responsive ways of managing partnerships. The paper is based on experience with the Enabling Rural Innovation (ERI) in Africa programme. Results highlight the dynamic process of partnership formation and the key elements that contribute to success. These include: (i) shared vision and complementarity, (ii) consistent support from senior leadership; (iii) evidence of institutional and individual benefits; (iv) investments in human and social capital; (v) joint resources mobilization. However, key challenges require coping with high staff turnover and over‐commitment, conflicting personalities and institutional differences, high transaction costs, and sustaining partnerships with the private business sector. The paper suggests that institutionalizing multi‐stakeholder partnerships requires participatory reflective practices that help structure and enhance learning, and incrementally help in building the capacity of research and development organisations to partner better and ultimately to innovate.     

ANALYZING THE IMPACT OF LAND USE ON SEWER SERVICE AREA PLANNING1

ABSTRACT: The density and distribution of land uses has important consequences for the planning of sewerage systems and for the costs of these systems. This paper examines these consequences using a simplified service area model. The model determines the area to be served by a central waste treatment plant, where alternative on-lot disposal systems are also available. The model is applied to various urban area configurations, which are summarized by their total populations and by their population density distributions. Both minimum regional cost and minimum local cost service area configurations are determined. In addition, the sensitivity of the model to the parameters of the cost and population density functions is assessed. It is found that the model is most sensitive to the parameters of the collection cost function.     

Environmental equity and electric power generation: Disparate community outcomes within Texas?

The examinations conducted in this study focus at the community level to test for disparate outcomes involving utility-based electric power generation within the crucial state of Texas. Potential policy implications are discussed as relevant to the general thesis of environmental racism postulated by justice advocates and the civil rights strategies advanced by justice advocates. Cross-sectional and longitudinal perspectives are used in testing for distributive inequities involving locations of fossil fuel power plants and emissions and output rates of emissions originating from such power plants. These tests provide empirical basis for assessing outcomes of the siting and emissions regulatory processes. While the civil rights strategies that would use Title VI of the Civil Rights Act of 1964 and the disparate impact standard are inapplicable, some limited findings indicate disparate outcomes involving other disadvantaged populations that are difficult to justify in context of legitimate market dynamics. Issues raised in this study have relevance to national energy policy proposals that promote many more power plants across the USA and encourage emissions trading.