Similar retardation of arsenic in gray Holocene and orange Pleistocene sediments: Evidence from field-based column experiments in Bangladesh.

Groundwater flow has the potential to introduce arsenic (As) in previously uncontaminated aquifers. The extent to which As transport is retarded by adsorption is particularly relevant in Bangladesh where low-As wells offer the best chance of reducing chronic exposure to As of a large rural population dependent on groundwater. In this study, column experiments were conducted with intact cores in the field to measure As retardation.

Highly bioavailable dust-borne iron delivered to the Southern Ocean during glacial periods.

Changes in bioavailable dust-borne iron (Fe) supply to the iron-limited Southern Ocean may influence climate by modulating phytoplankton growth and CO fixation into organic matter that is exported to the deep ocean. The chemical form (speciation) of Fe impacts its bioavailability, and glacial weathering produces highly labile and bioavailable Fe minerals in modern dust sources. However, the speciation of dust-borne Fe reaching the iron-limited Southern Ocean on glacial-interglacial timescales is unknown, and its impact on the bioavailable iron supply over geologic time has not been quantified.

High particulate iron(II) content in glacially sourced dusts enhances productivity of a model diatom.

Little is known about the bioavailability of iron (Fe) in natural dusts and the impact of dust mineralogy on Fe utilization by photosynthetic organisms. Variation in the supply of bioavailable Fe to the ocean has the potential to influence the global carbon cycle by modulating primary production in the Southern Ocean. Much of the dust deposited across the Southern Ocean is sourced from South America, particularly Patagonia, where the waxing and waning of past and present glaciers generate fresh glaciogenic material that contrasts with aged and chemically weathered nonglaciogenic sediments.

Estimation of reactive thiol concentrations in dissolved organic matter and bacterial cell membranes in aquatic systems.

Organic thiols are highly reactive ligands and play an important role in the speciation of several metals and organic pollutants in the environment. Although small thiols can be isolated and their concentrations can be estimated using chromatographic and derivatization techniques, estimating concentrations of thiols associated with biomacromolecules and humic substances has been difficult. Here we present a fluorescence-spectroscopy-based method for estimating thiol concentrations in biomacromolecules and cell membranes using one of the soluble bromobimanes, monobromo(trimethylammonio)bimane (qBBr).

Evaluation of a mental skills program for serving for an intercollegiate volleyball team.

A preseason mental skills program for serving was implemented for the 11 members of an intercollegiate volleyball team (M age = 20.0 yr.; SD = 1.

A laboratory study of satisfaction effects on mood state, withdrawal intentions, and organizational citizenship behavior.

154 undergraduates role-played a restaurant server experiencing positive, neutral, or negative Job or Life Satisfaction. Positive Satisfaction resulted in ratings of more positive reported mood state, lower expected absenteeism and turnover intentions, and greater expected Organizational Citizenship Behavior than did Neutral Satisfaction and Negative Satisfaction. Life Satisfaction was associated with reported mood states and intentions similarly to Job Satisfaction, except Negative Job Satisfaction was more negatively influential on expectations of quitting than Negative Life Satisfaction.

Comparison of constant and variable practice conditions on free-throw shooting.

The proposition that variable practice may be superior to constant practice even for consistent transfer situations was tested on a prototypical consistently performed skill, the basketball free throw. 94 participants were matched on free-throw shooting, then randomly assigned to one of four practice conditions, a Constant condition, i.e.