Search Results - (Author, Cooperation:D. L. Anderson)

2014-12-06

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

1750-3841

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Process Engineering, Biotechnology, Nutrition Technology

Electronic Resource

1749-6632

Blackwell Publishing Journal Backfiles 1879-2005

Natural Sciences in General

Electronic Resource

1600-0528

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Serial and cross-sectional cephalograms were read and the treatment files reviewed, for 521 children of a representative sample, the Burlington Growth Centre sample, to determine the frequency of congenially missing third molars. All the children had at least two cephalograms taken between the ages of 3 and 21 years, and one of these was taken around 16 years. Of the 521 children studied, 22.3 % had congenially missing third molars. There was no sex-specificity with respect to congenitally missing third molars or to the number of missing third molars in the maxilla and the mandible. Generally, more teeth were absent when third molars were congenitally missing. A relationship was found to exist between congenitally missing teeth and congenitally missing third molars in females. Thus, when third molars were absent, there was a sex-specificity for other congenitally missing teeth. The probability of specific teeth being missing was higher for those individuals with missing third molars than in the 1,191 10- to 12-year-old children of the overall Burlington Growth Centre sample.

Electronic Resource

1741-2358

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Periodontitis is a chronic disease of humans and animals which becomes more prevalent and severe with increasing age. The prevalent interpretation of the strong correlation between periodontal disease and age is that age merely occurs simultaneously during the extended time that irreversible loss of tooth support results from the accumulative effects of plaque and calculus. In both animals and humans, changes in the periodontium occur with age and are similar to those seen in the same type of tissues elsewhere in the body. To date, it is not clear to what extent these aging changes affect the response of the periodontium to local irritants. At all ages, periodontitis is more severe in mouths with abundant debris and calculus. However, even when these accumulations are minimal, periodontitis becomes more severe with age. Yet, not all elderly, and especially not all teeth in the elderly, suffer from destructive periodontal disease. The periodontium of old animals and humans retains the ability to respond adequately to changes in occlusal forces and to wounding, but the response is delayed in onset and duration. As well, the elderly are likely to suffer from other chronic diseases which may affect the periodontium and its therapy.

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] One conceptual model of weather is that of a series of events which are unconnected. That is, that the weather next week is essentially independent of the weather this week. However, although individual weather systems might be chaotic and unpredictable beyond a week or so, the statistics ...

Electronic Resource

1752-1688

Blackwell Publishing Journal Backfiles 1879-2005

Architecture, Civil Engineering, Surveying

Geography

: South Florida and the Everglades have been under intensive development since 1850 by Federal and State governments who encouraged and financed extensive drainage and hydraulic changes, primarily for agricultural settlement. Agricultural development of the sugar industry in the northern Everglades adjacent to Lake Okeechobee rapidly progressed only after the 1900s. Political and resource management conflicts have arisen because policies which once favored development are now being reversed by policies and regulation efforts to restore and conserve natural ecosystems. Currently, the environmental and ecological impacts of agricultural land use adjacent to natural wtlands of the Everglades are being assessed. The objectives of this paper are: (1) to outline the historical development of south Florida and the sugar industry, (2) to relate this history to political and management policy changes occurring as it pertains to ecosystem restoration and the multiuser competition for water/land resources, and (3) to propose how integrated resource management might be utilized for a sustainable Everglades and south Florida. This paper outlines the historical paradox of urban settlement, land development, and agricultural production, with efforts in the recent decade to acquire, manage, and preserve land and water resources for natural areas conservation. Only though the use of integrated resource management will the defined resource conflicts be mediated.

Electronic Resource

1752-1688

Blackwell Publishing Journal Backfiles 1879-2005

Architecture, Civil Engineering, Surveying

Geography

: The south Florida ecosystem and Lake Okeechobee are important water resource areas that have degraded due to changes in hydroperiod, water supply, and water quality. Approximately 56 percent of the total phosphorus in water discharged from the Everglades Agricultural Area (EAA) is in particulate form. Currently, farm-level best management practices are being implemented in the effort to reduce total phosphorus and sediment in off-farm discharges. The objective of this work was to develop and calibrate a model describing water movement in primary EAA canals as a first step to development of a water quality (i.e., nutrient, sediment) model. The Netherlands-developed mechanistic flow and water quality model (DUFLOW) was adapted for the EAA. Flow, stage, geometry, canal network, and meteorological data, October 13, 1993, to February 13, 1994, were used to adapt and calibrate the DUFLOW model for EAA water level and flow in primary canals. Direct runoff discharge into the primary canals from farm-pump stations was used as runoff input for the model. The model results are comparable to an independently-calculated water balance for the EAA. The calibrated flow model will be the basis for the calibration of sediment and chemical transport in the future.

Electronic Resource

1432-2153

Space shuttle ; Seismic wave ; Acoustic coupling

Springer Online Journal Archives 1860-2000

Physics

Technology

Abstract Shock waves generated by the space shuttles Columbia (August 13, 1989), Atlantis (April 11, 1991) and Discovery (September 18, 1991) on their return to Edwards Air Force Base, California, were recorded by TERRAscope (Caltech's broadband seismic network), the Caltech-U.S.G.S Southern California Seismic Network (SCSN), and the University of Southern California (USC) Los Angeles Basin Seismic Network. The spatial pattern of the arrival times exhibits hyperbolic shock fronts from which the path, velocity and altitude of the space shuttle could be determined. The shock wave was acoustically coupled to the ground, converted to a seismic wave, and recorded clearly at the broadband TERRAscope stations. The acoustic coupling occurred very differently depending on the conditions of the Earth's surface surrounding the station. For a seismic station located on hard bedrock, the shock wave (N wave) was clearly recorded with little distortion. Aside from the N wave, very little acoustic coupling of the shock wave energy to the ground occurred at these sites. The observed N wave record was used to estimate the overpressure of the shock wave accurately; a pressure change of 0.5 to 2.2 mbars was obtained. For a seismic station located close to the ocean or soft sedimentary basins, a significant amount of shock wave energy was transferred to the ground through acoustic coupling of the shock wave and the oceanic Rayleigh wave. A distinct topography such as a mountain range was found effective to couple the shock wave energy to the ground. Shock wave energy was also coupled to the ground very effectively through large man made structures such as high rise buildings and offshore oil drilling platforms. For the space shuttle Columbia, in particular, a distinct pulse having a period of about 2 to 3 seconds was observed, 12.5 s before the shock wave, with a broadband seismograph in Pasadena. This pulse was probably excited by the high rise buildings in downtown Los Angeles which were simultaneously hit by the space shuttle shock waves. The proximity of the natural periods of the high rise buildings and the modal periods of the Los Angeles basin enabled efficient energy transfer from shock wave to seismic wave.

Electronic Resource

1432-2218

Laparoscopic biliary surgery ; Common bile duct exploration ; Porcine model

Springer Online Journal Archives 1860-2000

Medicine

Abstract Advanced laparoscopic biliary procedures can be undertaken in a pig model, but the small size of the normal common bile duct makes learning difficult. We have developed a prepared pig model of common bile duct ligation on which to practice advanced laparoscopic biliary surgery. The pig's distal common bile duct was occluded using several different methods via a minilaparotomy. Laparoscopic biliary procedures were undertaken 6–21 days later. The common bile duct became dilated to between 2 and 3 cm in diameter in all cases, and this was well tolerated by the animals. All advanced laparoscopic biliary procedures were possible, including choledochoscopy, exploration of the bile duct, and cholecystojejunostomy. Short-term common bile duct ligation is well tolerated in pigs and can be used to create a model for practicing advanced laparoscopic biliary procedures.

Electronic Resource

1618-2650

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Summary Boron concentrations were determined by in-beam neutron capture prompt-γ activation analysis for 31 food and biological reference materials prepared by the National Institute of Standards and Technology, Agriculture Canada, the National Institute for Environmental Studies of Japan, and the International Atomic Energy Agency. Sensitivity and background enhancements that are consequences of neutron scattering in hydrogenous matrices such as biological reference materials are discussed, as are correction methods for nuclide interferences, with emphasis on sodium. The limit of quantitation for these materials is 1.0–2.5 μg/g and the limit of detection is 0.3–0.8 μg/g, depending on the irradiation time. For materials with boron levels ≥30 μg/g (e.g., most botanicals), the total analytical uncertainty is ≤2%.

Electronic Resource

1573-0867

Calcium silicate slag ; cane ; Everglades Agricultural Area ; Florida ; Histosols ; leaf Si ; magnesium ; nutrient antagonism ; organic soils ; Saccharum ; silicon ; soil testing ; stubble production ; sugar ; tissue testing

Springer Online Journal Archives 1860-2000

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Abstract In certain areas of the Everglades Agricultural Area, plant and ratoon sugarcane (Saccharum L.) yields are increased by application of Si from calcium silicate slag. The greatest yield responses are obtained in the plant crop the first year after application of slag and when plant uptake of Si is increased. Magnesium deficiencies have been reported after slag application. The objective of this study was to quantify interactions of soil and leaf nutrients on sugarcane grown on a Terra Ceia muck (Euic, hyperthermic Typic Medisaprist) that had previously received calcium silicate slag. Slag was applied at five rates, and yields were evaluated from plant, first-ratoon, and second-ratoon (stubble) crops at two locations. Soil and leaf from each crop were sampled for nutrient analysis and the results were used to interpret the yield data. Although slag increased cane yield by as much as 39% and sugar yield by 50%, for each 100 mg L−1 drop in extractable soil Mg, cane yields declined by 5.3 Mg ha−1 and sugar yields by 0.9 Mg ha−1. At leaf Si concentrations exceeding 10 g kg−1, optimum cane and sugar yields were observed, while leaf Mg concentrations approached critical leaf concentrations below 1.5 g kg−1. Estimates of total leaf nutrient uptake during each crop indicated that uptake of Mg did not meet nutrient demands at high biomass production. Nutrient antagonism between Si and Mg is suggested. Low soil Mg may contribute to the marked crop responses to slag and for the decline in stubble production. Application of a magnesium fertilizer may be necessary to maintain high nutrient availability.

Electronic Resource

1435-0661

Springer Online Journal Archives 1860-2000

Geosciences

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Saccharum spp.) is grown on high water table sandy soils that overlie limestone bedrock. This study determined treatment and site-specific factors affecting sugarcane production on these soils using a new statistical tool called tree regression. Sugarcane was grown in a 38-ha area for three seasons (1991, 1992, and 1993). Treatments were subirrigation water table depth (0.45 vs. 0.70 m), N fertilization frequency (13 vs. 7 split applications for 3 yr at 224 kg N ha-1 yr-1), and Mg fertilizer rate (0 vs. 60 kg Mg ha-1 yr-1), using a split-split plot design. Soil was sampled from plots before each crop to determine pH, and soil test P, K, Ca, Mg, and Si. Depth to rock was determined with ground-penetrating radar. Three statistical techniques were used to examine design and the effect of soil factors on sugarcane yield: traditional simple correlations, general linear mixed-model analysis (GLM) and MIXED), and a new technique, tree regression. Tree regression resulted in functions encompassing the complexity of response between yield, soil nutrients, and other factors, while handling large amounts of data. The regression tree identified sugarcane yields ranging from 42.6 to 100.8 t ha-1, grouped according to conditions defined by soil Ca, crop, soil Mg, the P "intensity/capacity" ratio, and water table level. The strength of the general linear mixed-model approach was in inference testing, whereas the strength of tree regression tree analysis is for prediction of covariate importance under broadly spaced environments.

Electronic Resource

1573-0662

Efficiency ; gas-phase ; multielement

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Geosciences

Abstract A simple system was constructed for the separation and collection of atmospheric particles and gases. The five-stage sampling train consists of a particle filter followed by four 7LiOH-impregnated filters to collect acidic gases. The treated filters quantitatively collect acidic gas-phase species of B, S, Cl, Br, I, As, Se, Sb and Hg. Simultaneous sampling with activated charcoal-impregnated and 7LiOH-treated filters revealed that B, S, and As species were found only as acidic gases, while the others had both acidic and nonacidic contributions. Concentrations of up to 48 elements on the particle filters and nine elements on the treated filters were determined using instrumental neutron activation analysis and neutron capture prompt γ-ray activation analysis. Minimum sampling volume estimates, average filter blank concentrations, and average atmospheric concentrations at College Park, MD and Wallops Island, VA are presented.

Electronic Resource

0029-5981

Engineering ; Engineering General

Wiley InterScience Backfile Collection 1832-2000

Mathematics

Technology

This paper is concerned with the effect of material properties, boundary friction, and inertia on the flow and strain patterns in material undergoing large plane strain compression. Experimental results are presented for both the rapid compression of Plasticine and the quasi-static compression of aluminium. In addition, a finite element code for rigid-plastic material behaviour is discussed, and approximate procedures are described for both in-plane and platen friction. Provision in the code was also made for strain hardening and strain rate sensitive material properties, and inertia effects. Comparison of the finite element and experimental results showed good agreement. Finite element calculations revealed that in-plane friction had a very significant effect on the strain patterns observed in the Plasticine experiments. Finite element calculations also showed that strain hardening was of fundamental importance in determining the strain patterns that were observed to occur in the quasi-static compression of aluminium.

14 Ill.

Electronic Resource

1588-2780

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Energy, Environment Protection, Nuclear Power Engineering

Abstract Analyses for certification have been made for the determination of 30 elements in the National Institute of Standards and Technology (NIST) Tomato Leaves renewal reference material, SRM 1573a. Three of the analytical techniques used were instrumental neutron activation analysis (INAA), radiochemical neutron activation analysis (RNAA), and prompt gamma activation analysis (PGAA). These techniques provided data on 19 elements by INAA, 10 elements by PGAA, and 7 elements by RNAA, with some overlap between techniques. For example, INAA was able to obtain overall analytical uncerainties (at the 95% confidence level) averaging ±2.2% for major and minor constituents (Ca, Mg, K), ±3.3% for constituents from 1 to 1000 μg/g (Na, Fe, Al, Mn, Ba, Zn, Rb, La, Cr), and ±6.4% for elements between 10 and 1000 ng/g (Co, V, Se, Th, Sc, Sb), using sample dry weights of approximately 150 mg. These analyses represent the most extensive use to date of nuclear analytical techniques in the certification of a trace element SRM at NIST.

Electronic Resource

1588-2780

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Energy, Environment Protection, Nuclear Power Engineering

Abstract Fifteen maple syrups were analyzed for137Cs and K (via40K) by using a low-background γ-ray counting system, and for B and K by using neutron capture prompt γ-ray activation analysis (PGAA). For low-background γ-ray counting, 3σ limits of detection (24-hour counts) were 0.03 Bq137Cs/kg and 10 mg K/kg for 3.5-L portions and 0.08 Bq137Cs/kg and 20 mg K/kg for 1.0-L portions. K concentrations determined by the two methods (using 2-g portions for PGAA) were in excellent agreement. The products were obtained in 1991, with one produced in Maryland, three in New York, four in Pennsylvania, two in New Hampshire, and five in Canada. The average activity concentration for Canadian syrups (2.8 Bq137Cs/kg) was nearly a factor of 20 greater than the average (0.15 Bq137Cs/kg) for the other syrups, but all137Cs activity concentrations were at least 100 times lower than those for which controls would be recommended according to Federal Radiation Council guidance. The data exhibited distinct groupings related to the sources of the products when the ratios of137Cs activity to K content (BqCs/mgK) were plotted vs. B concentrations.

Electronic Resource

1588-2780

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Energy, Environment Protection, Nuclear Power Engineering

Abstract At the National Institute of Standards and Technology, there are two techniques for chemical analysis that use neutron beams from the reactor for target irradiation: neutron depth profiling (NDP) and prompt γ-ray activation analysis (PGAA). There are two facilities for each technique, one equipped with a thermal neutron beam and the other, with a cold neutron beam. In addition, focused beams of cold neutrons will be used to measure the two-dimensional element distributions by PGAA and three-dimensional distributions by NDP. This paper includes a brief description of the facilities, the measurement capabilities of each, some recent applications of NDP and PGAA, and neutron focusing as applied to these techniques.

Electronic Resource

1588-2780

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Energy, Environment Protection, Nuclear Power Engineering

Abstract Background enhancements in neutron capture prompt γ-ray activation analysis were determined over a large range of total scattering cross sections by irradiating graphite, S, Be, paraffin, urea and H2O targets. Relative to irradiations using no target, B, Na, Cl, Al, and Pb backgrounds were 7–12 times greater with 2 ml of H2O, but N and Fe backgrounds were only 1.2 and 1.75 times greater, respectively. For biological targets, background count rates can be determined as functions of the 2223 ke V H photopeak count rate.

Electronic Resource

1588-2780

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Energy, Environment Protection, Nuclear Power Engineering

Abstract Twenty-one ready-to-use hobby glazes, of which 18 were labeled “safe for food containers” (SFFC), were analyzed for Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, Gd, Hf, K, Mn, Na, Pb, Si, Sm, Sr, Ti, Zn, and Zr by neutron capture prompt γ-ray activation analysis (PGAA). Simultaneously, Pb was also determined by X-ray fluorescence spectrometry (XRFS) using Pb K X-rays induced by the γ-ray component of the neutron beam. The XRFS limits of detection were 200–400 μg Pb·g−1 (dry weight), a factor of ∼ 100 better than those for PGAA. Pb concentrations (by dry weight; with weight losses ranging from 28 to 49% after air-drying) found were 0.16–27.2% in the SFFC glazes and 0.86–32% in the other glazes. The SFFC glazes contained from 〈0.6 to 202 μg Cd·g−1, and Co, Cr, and Cu (elements which may enhance Pb leaching from fired glazes) were found in concentrations up to 1.2, 2.7, and 5.6%, respectively. Method accuracy was demonstrated with the analysis of soil, fly ash, and glass standard reference materials.

Electronic Resource