The Use of Opal Phytolith Analysis in a Comprehensive Environmental Study: An Example from 19th-Century Lowell, Massachusetts

The value of opal phytolith analysis is demonstrated in a comprehensive environmental study of a historical site, the Kirk Street Agents\u27 House, Lowell, Massachusett. A method to measure phytolith degradation percentages is tested and shown to yield similar results to pollen corrosion indices; further research on this new method is suggested, however. Fluctuations in two classes of grass phytoliths indicate changing environmental conditions that support and expand upon changes noted in the pollen spectra. The results of the phytolith analysis are integrated with information derived from documentary research, artifactual analysis, stratigraphic interpretation, and other ethnobotanical methods to arrive at conclusions based on a truly multicomponent strategy. All lines of evidence point to a series of discrete occupational episode at the Kirk Street Agents\u27 House coupled with con-comitant changes in the use of yard space

Ground Water Hydrochemistry in the Southeastern Hueco Bolson and Southwestern Diablo Plateau, Trans-Pecos Texas

The hydrochemical history of groundwater in the arid southeastern Hueco Bolson and southwestern Diablo Plateau was investigated by collecting soil-moisture samples from unsaturated siliciclastic bolson-fill sediments and groundwater samples from the Diablo Plateau aquifer, the Hueco Bolson silt and sand aquifer, and the Rio Grande alluvial aquifer. Major, minor, and trace solutes, stable isotopic compositions, and activities of tritium and carbon-14 were measured in groundwater samples; major solute concentrations were determined in soil-moisture samples. Soil samples were collected to determine the type and amount of material that could be readily dissolved by recharge water. Core samples of Cretaceous carbonate and bolson-fill material were analyzed to determine the mineralogy of sediment and aquifer matrix. The Hueco Bolson and Diablo Plateau aquifers contain mainly sodium-sulfate groundwater that derived solutes by calcite, dolomite, and gypsum dissolution, coupled with exchange of aqueous calcium and magnesium for sodium on clay minerals and other ion-exchange sites. Rio Grande groundwater is dominated by sodium and chloride derived from dissolution of salts precipitated in irrigated fields during times of high evaporation. All groundwaters are inferred to acquire major compositional characteristics early in the flow history, principally through reactions in the unsaturated zone. Ages estimated from tritium and carbon-14 activities show that Rio Grande groundwaters are youngest, reflecting the short flow paths from the river to sampled wells following irrigation and percolation. Young groundwater is also found in the Diablo Plateau aquifer at wells both on the plateau and near the toe of the plateau escarpment. These are inferred to be recharge waters that rapidly moved along fractures to the water table. Other groundwater samples from the Diablo Plateau and Hueco Bolson aquifers are as much as 28,000 years old. Carbon-14 ages and tritium activities do not vary uniformly along a flow path. However, the oldest waters are found in wells near the center of the bolson pediment, and the distribution of carbon-14 ages generally conforms to the salinity distribution, suggesting a systematic relation between residence time, chemical and isotopic composition of groundwater, and regional hydrologic properties of the aquifers.Bureau of Economic Geolog

Ground Water Hydrochemistry in the Southeastern Hueco Bolson,Trans-Pecos Texas

The hydrochemical history of groundwater in the arid southeastern Hueco Bolson was investigated by collecting soil-moisture samples from unsaturated siliciclastic bolson-fill sediments and groundwater samples from the Diablo Plateau aquifer, the Hueco Bolson silt and sand aquifer, and the Rio Grande alluvial aquifer. Major, minor, and trace solutes, stable isotopic compositions, and activities of tritium and carbon-14 were measured in groundwater samples, while major solute concentrations were determined in soil-moisture samples. Soil samples were collected to determine the type and amount of material that could be readily dissolved by recharge water. Core samples of Cretaceous carbonate and bolson-fill material were analyzed to determine the mineralogy of sediment and aquifer matrix. The Hueco Belson and Diablo Plateau aquifers predominantly contain Na-SO4 groundwater, derived from solutes through carbonate and gypsum dissolution, coupled with the exchange of aqueous calcium and magnesium for sodium on clay minerals and other ion exchange sites. Rio Grande groundwater is dominated by sodium and chloride, derived from the dissolution of salts precipitated in irrigated fields during periods of high evaporation. Major compositional characteristics of all groundwater types appear to be acquired early in the flow history, primarily through reactions in the unsaturated zone. Ages estimated from tritium and carbon-14 activities indicate that Rio Grande groundwater is the youngest, reflecting short flow paths from land surface following irrigation, infiltration, and deep penetration from the river to sampled wells. Groundwater from the Diablo Plateau and Hueco Bolson aquifers ranges in age from a few hundred to nearly 29,000 years. Carbon-14 ages and tritium activities do not vary systematically along a flow path; however, the oldest waters are found in wells near the center of the bolson pediment. The irregular distribution of carbon-14 and tritium suggests that the Bolson and Diablo Plateau aquifers are internally complex, and flow velocities are not readily predictable solely based on the potentiometric gradient and estimates of regional porosity and permeability data.Bureau of Economic Geolog

Knock-Limited Performance of Triptane and 28-R Fuel Blends as Affected by Changes in Compression Ratio and in Engine Operating Variables

A knock-limited performance investigation was conducted on blends of triptane and 28-P fuel with a 12-cylinder, V-type, liquid-cooled aircraft engine of 1710-cubic-inch displacement at three compression ratios: 6.65, 7.93, and 9.68. At each compression ratio, the effect of changes in temperature of the inlet air to the auxiliary-stage supercharger and in fuel-air ratio were investigated at engine speeds of 2280 and. 3000 rpm. The results show that knock-limited engine performance, as improved by the use of triptane, allowed operation at both take-off and cruising power at a compression ratio of 9.68. At an inlet-air temperature of 60 deg F, an engine speed of 3000 rpm ; and a fuel-air ratio of 0,095 (approximately take-off conditions), a knock-limited engine output of 1500 brake horsepower was possible with 100-percent 28-R fuel at a compression ratio of 6.65; 20-percent triptane was required for the same power output at a compression ratio of 7.93, and 75 percent at a compression ratio of 9.68 allowed an output of 1480 brake horsepower. Knock-limited power output was more sensitive to changes in fuel-air ratio as the engine speed was increased from 2280 to 3000 rpm, as the compression ratio is raised from 6.65 to 9.68, or as the inlet-air temperature is raised from 0 deg to 120 deg F

Fertilizer Recommendations for the High Plains.

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Privatizing Regulation: Whistleblowing and Bounty Hunting in the Financial Services Industries

Addresses use of whistleblowers and suggests private enforcement methodologies to supplement or supplant public enforcement activities in financial services under new law

Determinants of urinary concentrations of dialkyl phosphates among pregnant women in Canada — Results from the MIREC study

AbstractOrganophosphate (OP) insecticides are commonly used in agriculture. Their use decreased in recent years as they were gradually replaced by other pesticides, but some OPs are still among the insecticides most used in Canada. Exposure to elevated levels of OPs during pregnancy has been associated with adverse birth outcomes and poorer neurodevelopment in children. The objective of the present study was to examine the relationship between the concentrations of OP pesticides urinary dialkyl phosphate (DAP) metabolites and various factors that are potential sources of exposure or determinants of DAP levels. In the Maternal-Infant Research on Environmental Chemicals (MIREC) Study, six DAPs were measured in 1st trimester urine samples of 1884 pregnant women living in Canada. They were grouped into sums of dimethyl alkyl phosphates (DMAP) and diethyl alkyl phosphates (DEAP) for statistical analysis. We found that 93% of women had at least one DAP detected in their urine. Geometric means (GM) of specific gravity-corrected levels for urine dilution were 59 (95% CI 56–62) and 21 (95% CI 20–22) nmol/L for DMAP and DEAP, respectively. The following characteristics were significantly associated with higher urinary concentrations of DMAP or DEAP: higher education, nulliparous, normal pre-pregnancy body mass index, non-smoker, not fasting at sampling, winter season at sampling, and early and late day collection times. Dietary items that were significantly related with higher urinary concentrations included higher intake of citrus fruits, apple juice, sweet peppers, tomatoes, beans and dry peas, soy and rice beverages, whole grain bread, white wine and green and herbal teas. This study indicates that exposure to these compounds is quasi-ubiquitous. The factors associated with greater DAP levels identified here could be useful to regulatory agencies for risk analysis and management. However, some exposure misclassification might occur due to the single DAP measurement available, and to the presence of preformed DAPs in the environment