Separation of Powers and Appointee Ideology

The traditional view of appointments to executive agencies isthat the president has virtual carte blanche in the selectionof personnel for his "team." Yet many formal models of appointmentsuggest that presidents must accommodate the policy preferencesof senators when making nominations. Several empirical studieshave confirmed that legislative preferences are a significantdeterminant of the ideology of appointees, but these studieshave focused on appointments to the federal judiciary; the researchhas not addressed appointments to executive agencies. Appointmentsto executive agencies from 1936 to 1996 are examined, by employinga special sample of appointees to those positions—thosewho have served in Congress at some point in their careers.For these "bridging" individuals, it is possible to analyzestrictly comparable measures of ideology for the appointees,their nominating presidents, and the senators who voted to confirmthem. A linear regression analysis provides significant supportfor the hypothesis that appointee ideology is affected by variationin the ideological tilt in Congress.     

Microsensor measurement of oxygen concentration in biofilms: from one dimension to three dimensions.

In this study, we measured oxygen concentration in biofilms in one dimension in field conditions and in three dimensions in laboratory conditions by using a robust oxygen microsensor in combination with an automation and data acquisition system. The biofilms were on the discs of rotating biological contactors treating domestic wastewater. The results of this study provide experimental evidence on oxygen distribution in wastewater biofilms and on biofilm structure. (1) The three dimensional measurements of oxygen concentration in biofilms revealed "pockets" of oxygen in deep sections of biofilms. In these isolated "pockets," located 600-760 microm from the biofilm surface, dissolved oxygen concentration was as high as 1 mg/L. This depth of oxygen diffusion is deeper than what was determined based on one dimensional measurements. (2) The heterogeneity of oxygen distribution was related to the surface structure of biofilms. The structure of the biofilm surface affected the diffusion boundary layer over the surface and, in turn, the oxygen diffusion and distribution inside biofilms. (3) Oxygen concentration in biofilms changed generally from a high degree of heterogeneity near the biofilm surface to a low degree of heterogeneity in deep sections of biofilms, indicating a cell-clusters-like structure near the surface and a more compact base layer close to the substratum.     

Measuring changes in water-related health and hygiene practices by developing-community households.

A population sample from a community in a developing urban area (Botshabelo), which obtains its treated water supply from a communal standpipe system, was subjected to a short Health and Hygiene Awareness and Education (HHA&E) programme to improve its practices on storing water in, and handling water from, storage containers at home. The problem was that the community's practices lead to the deterioration of the microbiological quality of the water in domestic storage containers. Measuring changes in the practices, as well as the microbiological quality of water in the containers, were the instruments used to determine whether the programme had a positive educational effect. This paper reports on selected elements of the practices measurement. Structured interviews, observations and statistical analyses assessed three variables--container hygiene, container storage and hand hygiene. Results indicated insignificant improvements in practices. This was supported by insignificant improvements in the microbiological water quality, that was still above health-safety limits. This implied that short-term "quick fix" HHA&E programmes would tend to be ineffective. Results also suggested that some negative water-hygiene habits may readily change (container hygiene and storage), while behaviour of a more personal nature, such as hand-washing, was not easily changed.     

Comparison of field olfactometers in a controlled chamber using hydrogen sulfide as the test odorant.

A standard method for measuring and quantifying odour in the ambient air utilizes a portable odour detecting and measuring device known as a field olfactometer (US Public Health Service Project Grant A-58-541). The field olfactometer dynamically dilutes the ambient air with carbon-filtered air in distinct ratios known as "Dilutions-to-Threshold" dilution factors (D/Ts), i.e. 2, 4, 7, 15, etc. Thirteen US states and several cities in North America currently utilize field olfactometry as a key component of determining compliance to odour regulations and ordinances. A controlled environmental chamber was utilized, with hydrogen sulfide as the known test odorant. A hydrogen sulfide environment was created in this controlled chamber using an Advanced Calibration Designs, Inc. Cal2000 Hydrogen Sulfide Generator. The hydrogen sulfide concentration inside the chamber was monitored using an Arizona Instruments, Inc. Jerome Model 631 H2S Analyzer. When the environmental chamber reached a desired test concentration, test operators entered the chamber. The dilution-to-threshold odour concentration was measured using a Nasal Ranger Field Olfactometer (St Croix Sensory, Inc.) and a Barnebey Sutcliffe Corp. Scentometer. The actual hydrogen sulfide concentration was also measured at the location in the room where the operators were standing while using the two types of field olfactometers. This paper presents a correlation between dilution-to-threshold values (D/T) and hydrogen sulfide ambient concentration. For example, a D/T of 7 corresponds to ambient H2S concentrations of 5.7-15.6 microg/m3 (4-11 ppbv). During this study, no significant difference was found between results obtained using the Scentometer or the Nasal Ranger (r = 0.82). Also, no significant difference was found between results of multiple Nasal Ranger users (p = 0.309). The field olfactometers yielded hydrogen sulfide thresholds of 0.7-3.0 microg/m3 (0.5-2.0 ppbv). Laboratory olfactometry yielded comparable thresholds of 0.64-1.3 microg/m3 (0.45-0.9 ppbv). These thresholds are consistent with published values.     

The attribute rating test for sensory analysis.

This new sensory method evaluates the intensity of an odorant by using a modified "paired-comparison" format. It can be applied to any situation for which the odor-causing agent is known and a purified standard is available. The attribute rating test requires that a standard solution of the odorant be prepared at a concentration that is both readily recognized by most individuals and likely to evoke customer complaints. Within an hour individuals can be trained to compare the odor type and intensity of the standard to water samples, then rate the odor in the sample as "not detected," "less than the standard," "equal to standard," or "greater than the standard." The attribute rating test was successfully used by a full-scale water treatment facility to monitor the intensity of geosmin in the source water and to determine the effectiveness of powdered activated carbon for controlling its earthy-odor in treated water.     

Nitrogen removal from pharmaceutical manufacturing wastewater via nitrite and the process optimization with on-line control.

In this study, laboratory scale experiments were conducted to investigate the nitrogen removal from pharmaceutical manufacturing wastewater. The results indicate that by selective inhibition of free ammonia on oxidizers, nitrogen removal can be achieved by nitritation and denitritation process. The nitrite ratio was above 98% in the aerobic stage and the nitrogen removal efficiency was about 99%. The complete ammonia removal corresponded exactly to the "Ammonia Valley" in the pH versus time graphic and the anoxic reaction was completed when the "Nitrite Knee" appeared in the ORP versus time graphic. Optimization of the SBR cycle by step-feed and on-line control with pH and ORP strategy allowed the carbon and energy saving. The easy operation and the low cost make the SBR system an interesting option for the biological nitrogen removal from the pharmaceutical manufacturing wastewater.