Abusive and nonabusive parental treatment from the child's perspective.

Interviewed 14 8–14 yr old boys who had been abused by their parents and 10 nonabused counterparts. Ss' perceptions of parental characteristics, discipline techniques, and emotional acceptance/rejection were examined in addition to Ss' attributions for parental treatment. Differences between the perceptions of abused and nonabused Ss were found, and wide variation was discovered in the perceptions of abused Ss. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Collective behaviour in two-dimensional cobalt nanoparticle assemblies observed by magnetic force microscopy

The use of magnetic nanoparticles in the development of ultra-high-density recording media is the subject of intense research. Much of the attention of this research is devoted to the stability of magnetic moments, often neglecting the influence of dipolar interactions. Here, we explore the magnetic microstructure of different assemblies of monodisperse cobalt single-domain nanoparticles by magnetic force microscopy and magnetometric measurements. We observe that when the density of particles per unit area is higher than a determined threshold, the two-dimensional self-assemblies behave as a continuous ferromagnetic thin film. Correlated areas (similar to domains) of parallel magnetization roughly ten particles in diameter appear. As this magnetic percolation is mediated by dipolar interactions, the magnetic microstructure, its distribution and stability, is strongly dependent on the topological distribution of the dipoles. Thus, the magnetic structures of three-dimensional assemblies are magnetically soft, and an evolution of the magnetic microstructure is observed with consecutive scans of the microscope tip.     

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.     

Automated detection of ocular alignment with binocular retinal birefringence scanning

We previously developed a retinal birefingence scanning (RBS) device to detect eye fixation. The purpose of this study was to determine whether a new binocular RBS (BRBS) instrument can detect simultaneous fixation of both eyes. Control (nonmyopic and myopic) and strabismic subjects were studied by use of BRBS at a fixation distance of 45 cm. Binocularity (the percentage of measurements with bilateral fixation) was determined from the BRBS output. All nonstrabismic subjects with good quality signals had binocularity >75%. Binocularity averaged 5% in four subjects with strabismus (range of 0-20%). BRBS may potentially be used to screen individuals for abnormal eye alignment.     

Laser-generated spark morphology and temperature records from emission and Rayleigh scattering studies

Using both Rayleigh scattering and time-resolved emission spectroscopy, we have recorded the spatial and temporal evolution of laser-generated sparks in argon from changes during the first ten of nano-seconds to complete dissipation, which occurs in a time span of approximately 5 ms. Maps of either emission intensity or argon density spanning the entire region affected by the energy deposited by the laser show the dissipation of the spark in detail. Immediately after ignition, the argon plasma occupies an ellipsoidal volume of roughly 3-mm vertical (axial) length. After approximately 20-40 micros, the spark region has transformed into a toroidal shape in a plane perpendicular to the vertical axis, with a radius of approximately 1.5 mm. The torus rises slowly up and expands noticeably in the radial direction. A record of peak temperatures of the spark ranging from approximately 10,000 K at 60-micros delay time to approximately 450 K at 4-ms delay time indicate cooling rates from approximately 100 to 1 K/micros at these times.     

Effects of atmospheric ozone on microarray data quality

A data anomaly was observed that affected the uniformity and reproducibility of fluorescent signal across DNA microarrays. Results from experimental sets designed to identify potential causes (from microarray production to array scanning) indicated that the anomaly was linked to a batch process; further work allowed us to localize the effect to the posthybridization array stringency washes. Ozone levels were monitored and highly correlated with the batch effect. Controlled exposures of microarrays to ozone confirmed this factor as the root cause, and we present data that show susceptibility of a class of cyanine dyes (e.g., Cy5, Alexa 647) to ozone levels as low as 5-10 ppb for periods as short as 10-30 s. Other cyanine dyes (e.g., Cy3, Alexa 555) were not significantly affected until higher ozone levels (> 100 ppb). To address this environmental effect, laboratory ozone levels should be kept below 2 ppb (e.g., with filters in HVAC) to achieve high quality microarray data.