Fugacity-based indoor residential pesticide fate model

Dermal and nondietary pathways are possibly important for exposure to pesticides used in residences. Limited data have been collected on pesticide concentrations in residential air and surfaces following application. Models may be useful for interpreting these data and to make predictions about concentrations in the home for other pesticides based on chemical properties. We present a dynamic mass-balance compartment model based on fugacity principles. The model includes air (both gas phase and aerosols), carpet, smooth flooring, and walls as model compartments. Six size fractions of particulate matter with different fate and transport properties are included. We determine the compartmental fugacity capacity and mass-transfer rate coefficients between compartments. We compare model results to chlorpyrifos air and carpet measurements from an independent study. For a comparison, we run the same simulation for diazinon and permethrin. We quantify the effect of parameter uncertainty and model uncertainties related to the source release rate and conduct a sensitivity analysis to determine which parameters contribute most to output uncertainty. In the model comparison to chlorpyrifos measurements, the model results are of the same order of magnitude as measured values but tend to overpredict the measured data, thus indicating the need for a better understanding of emissions from treated surfaces.     

Determining subsea permafrost characteristics with a cone penetrometer — Prudhoe Bay,Alaska

Sediments beneath the Beaufort Sea near Prudhoe Bay, Alaska, were probed at 27 sites using a static cone penetrometer to determine engineering properties and distribution of material types, including ice-bonded sediments. The probe, designed and constructed at the Cold Regions Research and Engineering Laboratory, provided both point and casing resistance data and thermal profiles. At five sites these data were correlated with information from adjacent drilled and sampled holes. These control data and the quality of the probe information permitted profiles of sediment type and occurrence of ice-bonded material to be developed along three lines that included various geological features and depositional environments.Material properties were quite variable in the upper 14 m of sediments probed. In general, softer, finer-grained sediments occurred in the upper layers, while penetration refusal was met in stiff gravels 10 to 12 m below the seabed.Seabed temperatures during the study were all below 0°C. However, because of uncertainties in freezing point values caused by brines, evaluation of the penetration resistance data was required to identify the occurrence of ice-bonded sediments. The coupling of thermal and penetration resistance data revealed that seasonally ice-bonded sediments occurred where the sea ice froze back to or near the seabed. Deeper, perennially frozen sediments also appeared to be present at several probe sites.     

Conditions affecting production of a protein isolate from lupin seed kernels

Conditions were investigated to determine the optimum processing parameters for preparation of a protein isolate from the ground, dehulled lupin seeds of Lupinus angustifolius. The extraction variables were: particle size (16–100 mesh); pH (2–11); extraction medium; solvent to lupin ratio (10:1 to 40:1); temperature (20–60^oC) and time (15–60 min). The isoelectric point of the lupin protein was found to be pH 4.5 with a protein solubility of greater than 90% above pH 8.0. Using 60–100 mesh ground lupin and extracting at pH 8.5 for 30 min, a protein isolate was obtained on acidification to pH 4.8 which was 89.4% protein compared to 34.0% protein for the original dehulled lupin. This protein isolate represented 19.8% of the starting material and 52% of the starting nitrogen. Similar results were also obtained when hexane defatted lupin was used. In this case the protein isolate had a protein content of 92.5%. The yield of protein isolate could be increased to 25.7% of the starting material if the extraction was repeated. The protein efficiency ratio for the protein isolate was 2.90 when supplemented with methionine.     

Effects of intermittent, moderate intensity noise stress on human performance.

Studied the effects of prolonged exposure to 2 noise stressors (random and patterned intermittent 0 and 85 db) on the performance of 60 male undergraduates on 3 tasks requiring different abilities (reaction time, rate control, and time-sharing). The sensitivity of alternate metrics of performance degradation was also evaluated within an analysis of covariance design. Ss were randomly assigned to the various treatments, and a series of 2 * 2 * 4 (Noise Intensity * Noise Quality * Trial Blocks) covariance analyses were carried out. The effects of random noise on performance depended on the type of task and performance measure. The reaction-time task was affected, the rate-control task was not, and the time-sharing task was affected only after continued exposure to noise. Patterned noise had insignificant effects. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comment on the use of moderator variables.

Discusses the implications of the moderator variables for measurement theory and for personnel selection. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Scheduling and Transport for File Transfers on High-Speed Optical Circuits

Scheduling resources on Grids is a well-known problem. The extension of Grids to LambdaGrids requires the scheduling of lambdas, i.e., end-to-end high-speed circuits. In this paper, we propose a scheduling heuristic for such lambdas in support of large-scale scientific applications that require high-throughput transfers of large files. We refer to this heuristic as Varying-Bandwidth List Scheduling (VBLS) because the scheduler returns a Time-Range-Capacity (TRC) allocation vector with varying bandwidth levels assigned for different time ranges within the duration of a transfer. The advantage of VBLS over a fixed-bandwidth allocation scheme is that it allows the scheduler to backfill any holes left in resource allocations. Enabling VBLS requires end host applications to specify the file size in their transfer requests. To characterize VBLS, we ran simulation experiments that show that VBLS performance approaches packet-switching performance. This result means that file transfers can take advantage of bandwidth that becomes available subsequent to the start of transfers, a current and critical drawback of typical fixed-bandwidth allocation schemes in circuit-switched networks. Next, we identify the key features needed in a transport protocol that works in conjunction with VBLS and develop the Varying Bandwidth Transport Protocol (VBTP). VBTP is a rate based flow control scheme that is coupled with Selective-ARQ based error control. Finally, the paper concludes with a discussion on the impact of transport problems on VBLS scheduling.     

Application of a nonuniform spectral resampling transform in Fourier-transform spectrometry

We describe a nonuniform spectral resampling transform (NUSRT) that resamples a frequency-scaled spectrum that has been measured by a Fourier-transform spectrometer (FTS). Frequency scaling of a spectrum can arise from measurements made with off-axis detectors and Doppler shift induced by motion of a spaceborne FTS relative to an input radiation source. In addition, a spectrum may need to be rescaled in frequency to match spectral lines for applications such as the retrieval of atmospheric state parameters. The NUSRT is cast as a linear algebraic expression that relates a nonuniformly sampled interferogram to an input spectrum. A polynomial approximation is applied to this expression that reduces the inverse of the NUSRT to a series of Fourier transforms that can be implemented as fast Fourier transforms (FFTs). We show that this NUSRT algorithm requires on the order of 6N log N flops, which reduces the computational cost of rescaling by more than 1 order of magnitude compared with conventional FFT-based Shannon interpolation techniques while comparable accuracy is maintained.