Nitrates and bacterial distribution in rural domestic water supplies

The protection of underground water resources in an important facet of the Safe Drinking Water Act. Effective intervention strategy for active source protection requires up-to-date information on ground water quality and the knowledge of potential sources and causes of contamination. In the present study the state of well water supplies in rural East Texas was evaluated in order to develop a practical approach to surveying water sources in ‘back-country’ areas, which would allow the differentiation of natural from anthropogenic factors affecting water quality. The specific focus was on nitrates, their extent, causes and sources in rural well water. Data were processed using synographic mapping which permitted the comparison of the natural tendency in distribution of nitrates with the patterns induced by man's activities. Trend surface analysis of data indicated that the surveyed Tertiary and Quaternary sands were not naturally nitrate-rich. Localized and well-defined spots of nitrates, many times in excess of the background, were traceable to the anthropogenic sources. The study identified the characteristics of high risk wells.     

Learning a menu selection tree: training methods compared

. Menu selection systems sometimes present learning problems for novice users. This comparison of four training methods for novice users found that the global tree diagram of the menu system was superior to command sequence and frame presentation methods, and somewhat better than trial and error. Methods were evaluated on the basis of (1) number of target nodes found, (2) mean number of selections to a target node, (3) recall of the menu structure, and (4) subjective rating of ease of learning.     

Phrasing cues and hierarchical organization in serial pattern learning by rats.

In Exp I, 42 female albino Sprague-Dawley rats received food quantities in a T-maze in a serial pattern. Ss learned under either no cue, temporal cue, place cue, and/or combined temporal-place cue conditions. In Exp II, 45 female albino Sprague-Dawley rats in the T-maze were trained in complex subpatterns with place cues or no cues. Exp I showed that phrasing facilitated pattern learning as long as phrasing cues were available but that Ss learned different things when different kinds of phrasing cues were used. Exp II showed that phrasing a pattern into formally complex rather than formally simple chunks produced poor learning. Overall findings demonstrate the rat's capacity to abstract and use higher-order rules in hierarchical serial patterns, especially when phrasing cues are available to facilitate the process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The evolution of AVHRR-derived water temperatures over boreal lakes

Higher spatial resolution in Earth–atmosphere models requires improved information on surface fields with very different thermal characteristics, such as land and water. Remote sensing is a useful tool for this purpose. A method is presented here to determine and compare the temperature evolution of water bodies. Thermal IR observations were extracted from NOAA's advanced very high-resolution radiometer (AVHRR) satellite data over the period from April 1 to August 31, 1994. The IR temperatures were calibrated and adjusted to account for the intervening atmosphere. For each day, 1-km resolution temperature scenes were generated for a 1000×1000-km rectangular region extending from about 60°N, 111°W over the northern part of the Canadian Province of Alberta to about 50°N, 97°W in southern Manitoba. There are 132 water bodies of area larger than 100 km² in this study area. The temperature cycle over these water bodies can be decomposed into a straight line with a small positive slope for spring ice break-up, followed by a fitted quadratic curve for the summer temperature variations. The curve fit parameters give information on the transition between ice and ice-free conditions. Data stratification confirms a strong latitudinal influence on the shape of the curves. It was not possible to quantify the effect of water depth, as the depth of most boreal lakes is not known. Instead, a list of fit coefficients for all the water bodies is provided. Once detrended from the quadratic curves, the amplitude of the diurnal cycle and major variations in temperatures of the water bodies can be determined. The detrended water temperature variations are about one-third the magnitude of the detrended air temperature variations from nearby weather stations.     

Perceptual laterality and iconic recognition of visual materials by Korsakoff patients and normal adults.

Compared 9 male patients with Korsakoff's syndrome to 19 normal and 11 alcoholic control Ss on their threshold for recognition of words or patterns presented monocularly to the lateral visual fields. Ss were then tested on backward visual masking of the same (target) stimuli to determine the interstimulus interval (ISI) needed to escape the masking effect (critical ISI) in each lateral field. Threshold for recognition and critical ISI were elevated in Korsakoff Ss. For all Ss, the right visual field was superior to the left for word recognition but not for pattern recognition. The critical ISIs were shorter in the right visual field for both types of material, suggesting that the dominant hemisphere is more efficient in the early (iconic) stages of information processing. (22 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emission control of SO2 and NOx by irradiation methods

Microwave discharges at 2.45 GHz frequency and accelerated electron beams operated at atmospheric pressure in synthetic gas mixtures containing N(2), O(2), CO(2), SO(2), and NO(x) are investigated experimentally for various gas mixture constituents and operating conditions, with respect to their ability to purify exhaust gases. An original experimental unit easily adaptable for both separate and simultaneous irradiation with microwaves and electron beams was set up. The simultaneous treatment with accelerated electron beams and microwaves was found to increase the removal efficiency of NO(x) and SO(2) and also helped to reduce the total required dose rate with approximately 30%. Concomitant removal of NO(x) ( approximately 80%) and SO(2) (>95%) by precipitation with ammonia was achieved.     

Optimization of instrumental colour analysis in dry-cured ham

Colour of dry cured ham was measured by instrumental techniques in order to determine the optimum measurement index. Five different colour systems were used: CIE L(?)a(?)b(?), Hunter Lab, CIE L(?)u(?)v(?), xyY and XYZ, each with illuminants D65, C and A, and with both 10 and 2° observer angles. Measurements were taken in both Semimembranosus (SM) and Biceps femoris (BF) muscles. Hunter Lab system with illuminant A gave the most reproducible results within muscles for the three colour parameters evaluated. A further comparison of results obtained with 10 and 2° observer angles of Hunter Lab with illuminant A showed there were no significant differences between the angles. Significant differences between results from SM and BF muscles were found in all the hams, the BF always showing higher values than SM for every colour parameter.     

Design and performance of an InGaAs-InP single-photon avalanche diode detector

This paper describes the design, fabrication, and performance of planar-geometry InGaAs-InP devices which were specifically developed for single-photon detection at a wavelength of 1550 nm. General performance issues such as dark count rate, single-photon detection efficiency, afterpulsing, and jitter are described.     

The role of partial grain boundary dislocations in grain boundary sliding and coupled grain boundary motion

We study the process of grain boundary sliding through the motion of grain boundary dislocations, utilizing molecular dynamics and embedded atom method (EAM) interatomic potentials. For a Σ = 5 [001]{310} symmetrical tilt boundary in bcc Fe, the sliding process was found to occur through the nucleation and glide of partial grain boundary dislocations, with a secondary grain boundary structure playing an important role in the sliding process. While the homogeneous nucleation of these grain boundary dislocations requires shear strain levels higher than 7%, preexisting grain boundary dislocations are shown to glide at applied shear levels of 1.5%. The glide of the dislocations results in coupled motion of the boundary in the directions parallel and perpendicular to itself. Finally, interstitial impurities and vacancies were introduced in the grain boundary to study the effects on the sliding resistance of the boundary. While vacancies and H interstitials act as preferred nucleation sites, C interstitials do not. Both hydrogen and C interstitials stop dislocation glide whereas vacancies do not. A detailed study of the dynamic properties of these dislocations is also presented.