bluuebunny/crossref_metadata_2025_split huggingface dataset:
The relation between glucovanillin, β‐d‐glucosidase activity and cellular compartmentation during the senescence, freezing and traditional curing of vanilla beans
Authors: Odoux E. , Escoute J. , Verdeil J.‐L. 
Published: July 2006

AbstractThe aim of this research was to improve our understanding of the mechanism of glucovanillin hydrolysis by β‐d‐glucosidase activity in vanilla beans by studying their senescence, freezing and traditional curing. A batch of green pods from Madagascar was ripened at 30°C until fruits turned black; another batch was frozen for few days at −18°C and defrosted at 35°C for 24 h and a third batch was cured using traditional methods. During treatments, samples were analysed for the yield of glucovanillin hydrolysis, and β‐glucosidase activity was measured. Cellular structures were also examined by light and transmission electron microscopy. Green fruits had a low yield of glucovanillin hydrolysis (<5%), a high level of β‐glucosidase activity (∼1000 nkatal g−1fresh weight) and a perfect cellular integrity. Senescent fruits had a high yield of glucovanillin hydrolysis (>95%), no measurable β‐glucosidase activity and complete cellular degradation. Similar results were observed in beans after defrosting. During curing, beans had a medium yield of glucovanillin hydrolysis (<50%), no measurable β‐glucosidase activity and partial cellular degradation compared with senescent or defrosted beans. Results show that the mechanism of glucovanillin hydrolysis in vanilla beans is regulated by cellular compartmentation and that the β‐glucosidase activity level is not the limiting factor for complete hydrolysis. If total decompartmentation is obtained, then complete glucovanillin hydrolysis is observed even if most of the β‐glucosidase activity is lost. The β‐glucosidase activity level only has an effect on glucovanillin hydrolysis kinetics.
Censusing and Measuring Lianas: A Quantitative Comparison of the Common Methods1
Authors: Schnitzer Stefan A. , DeWalt Saara J. , Chave Jérôme 
Published: July 2006

ABSTRACTLianas contribute to many aspects of tropical forest diversity and dynamics, and interest in liana ecology has grown substantially in recent years. Methods to census lianas and estimate biomass, however, differ among studies, possibly hindering attempts to compare liana communities. At Nouragues Research Station (French Guiana), we tested the extent to which liana abundance, basal area, and estimated biomass differed depending on stem diameter measurement location, inclusion of ramets, inclusion of lianas rooted within versus passing through the plot, and plot shape. We found that the mean per plot abundance and basal area of lianas were significantly greater when lianas were measured low on the stem, when ramets were included, and when lianas were sampled in transects (2 × 50 m) than in square plots (10 × 10 m). Mean per plot liana abundance and basal area were 21 percent and 58 percent greater, when stems were measured at the largest spot on the stem compared to 130 cm from the ground, respectively. Including liana ramets increased average per plot liana abundance, basal area, and estimated biomass by 19, 17, and 16 percent, respectively. To facilitate cross‐study comparisons, we developed conversion equations that equate liana abundance, diameter, and basal area based on the measurements taken at four different stem locations. We tested these equations at Lambir Hills National Park, Malaysia and found that they did not differ significantly between the two sites, suggesting that the equations may be broadly applicable. Finally, we present a new allometric equation relating diameter and biomass developed from 424 lianas from five independent data sets collected in four countries.
A theoretical treatment of the absorption spectra of all-benzenoid hydrocarbons
Authors: Troy T. P. , Schmidt T. W. 
Published: July 2006

Abstract
The class of compounds known as the all-benzenoid polycyclic aromatic hydrocarbons (ABPAHs) are treated with time-dependent density functional theory (TDDFT) and a modified Hückel theory to determine how large an ABPAH must be before it is found to absorb strongly in the visible region that corresponds to the bluest of the diffuse interstellar bands (DIBs). The first six ABPAHs are treated with TDDFT using the B3LYP functional to determine their excitation energies. A two-parameter Hückel theory is adopted to deal with those systems too large to be addressed with TDDFT. The transitions are calculated and fitted to experimental data. An ABPAH system with 84 carbons and 14 all-benzenoid rings is found to be the first carrier to absorb strongly in the region where DIBs are observed.
The Contributions of C. E. Jacob to Scientific Hydrology and Engineering Worksa
Authors: Spiegel Zane 
Published: July 2006

ABSTRACTC. E. Jacob was the first of a small group of hydrologists who followed C. V. Theis’ lead in application of the theory of nonsteady boundary value problems to both well hydraulics and regional ground‐water movement. Some of his scientific contributions were the explanation of the storage and elastic properties of artesian aquifers, the semi‐log method of aquifer test analysis, methods of analysis of tests on unconfined leaky aquifers, application of doublet theory to paired polarized heat‐pump wells, the theory of step and constant‐head aquifer tests by wells, salt‐water encroachment, the tutelage of hydrology students at several universities, solutions to hundreds of field problems encountered in his extensive consulting activities in many parts of the world, and his method of determining aquifer recharge and transmissivity from the response of water levels in wells to varying natural recharge. One of his last works was a study of the natural recharge to Southampton on Long Island, which showed that the recharge was much less than the 21 inches per year assumed previously.
Effect of Early Day Mining Operations on Present Day Water Qualitya
Authors: Mink Leland L. , Williams Roy E. , Wallace Alfred T. 
Published: July 2006

ABSTRACTMining operations within the Coeur d'Alene District of northern Idaho have been continuous for over 85 years. Data presented herein demonstrate that early day mining and milling wastes are now affecting the ground‐water quality in several locations. One of the affected areas is the lower Canyon Creek Basin located in the Coeur d'Alene District near Wallace, Idaho.Ground‐water pollution of the Canyon Creek Basin results from leaching of old mine tailings that are intermixed with the upper part of the sand and gravel aquifer. High zinc, lead and cadmium concentrations occur in ground water and soil samples taken from the portion of the sand and gravel aquifer containing old mine tailings.Analysis of water samples from a settling pond located in the upper portion of the study area indicates that the pond water is not the source of the heavy metal concentrations found in the ground water. However, the water from the pond's decanting system provides recharge to ground water and compounds the problem.
Probable Impact of NTA on Ground Watera
Authors: Dunlap William J. , Cosby Roger L. , McNabb James F. , Bledsoe Bert E. , Scalf Marion R. 
Published: July 2006

ABSTRACTLaboratory studies were employed to investigate the fate and effect of NTA both in ground waters and in soil profiles overlying ground waters.Studies of the sorption of NTA by sand, loam, and clay‐loam soils indicated that sorption of NTA on soils could slow its movement into and through ground waters. Sorption will probably not be sufficient to prevent or greatly reduce potential pollution of ground water by NTA used as a detergent builder.Soil column studies were employed to investigate the degradation and effect on metals of NTA infiltrating through soils. These studies indicated: NTA infiltrating through most unsaturated soils likely would undergo rapid and complete degradation and contribute only inorganic nitrogen compounds and carbonate to ground waters; NTA infiltrating through saturated soils would probably experience only very limited degradation, with a major portion entering ground water intact; any NTA which escaped degradation during infiltration through soils could transport such metals as iron, zinc, chromium, lead, cadmium, and mercury from soils into ground waters.Studies with model aquifers constructed from natural aquifer sand indicated that NTA would likely undergo slow degradation in essentially anaerobic ground‐water environments, with production of CO2, CH4, and possibly other organic compounds.
Effluent for Irrigation — A Need for Caution?a
Authors: Walker William H. 
Published: July 2006

ABSTRACTMost municipal waste treatment systems receive, treat, and eventually discard to some segment of the environment storm runoff and liquid wastes from all industrial, commercial, and domestic areas and establishments in the community. At any given time these wastes may contain viruses, antibiotics, hormones, nutrients, weedkillers, fungicides, pesticides, trace metals, and an almost countless number of toxic chemical compounds. Present treatment by the old, ineffectual sewage treatment methods and facilities still employed generally does not remove nor reduce to a harmless state all of the hazardous materials contained in the waste streams entering the plant. Some are more concentrated when they leave the plant in effluent and sludge than they were upon entry.Existing pollution protection laws prohibit surface‐water dilution of these effluents and sludges. Drying, burning, or distilling them is very costly, causes air pollution, and produces potentially hazardous chemical residues which still must be disposed of in some nonpolluting fashion. There are no “technologically feasible, economically reasonable” alternative methods of effectively treating these wastes to an acceptable quality level for discharge to streams. For these reasons, land disposal of sewage effluent and sludges now is being widely promoted and employed as the best available method of treatment.It is estimated that as many as 300 municipalities have gone to the land to solve their sewage plant waste problems in recent months. Many of these have been at least partially funded with State and Federal grants. If similar permits and financial assistance continue to be granted in the future, it is anticipated that several thousand municipalities will follow suit within the next few years.
Development of Fresh Ground Water Near Salt Water in West Virginiaa
Authors: Wilmoth Benton M. 
Published: July 2006

ABSTRACTSalt‐water migration into relatively shallow rocks in the western half of West Virginia is already rather far advanced. Because of the wide distribution of salty ground water and connate brine at various depths, it is difficult to determine how much of the contamination is natural and how much is the result of subsurface industrial activities. Although some local salt‐water problems are the result of oil and gas operations, much of the regional near‐surface salt water is a natural condition unrelated to deep drilling or other industrial activities.Ground water is usually more abundant from consolidated aquifers beneath the valleys than from beneath the ridges. However, the presence of shallow salt water beneath the valleys imposes limitations on the availability of fresh water from a single well. Because most well fields must be located along the populated valleys, the problem of interception of salt water is the most important factor limiting development of consolidated bedrock aquifers. By utilizing the history of development and operation of well fields, an estimate of the availability of fresh water can be made, and test drilling and new well field construction guided accordingly.During 1971 to 1974, more than a dozen small communities in Logan and Boone Counties started development of public‐water supplies from wells. Existing water‐supply problems in these areas are being solved by using the cumulative experience of other communities in the area. Ground water is currently being developed in valley areas of Logan County such as Man to Lorado, Essie to Big Creek, and Huff Creek to Mallory. Adequate well fields have recently been successfully constructed just above shallow salt water in bedrock aquifers at Hattie in Calhoun County, near Madison in Boone County, near Southside in Mason County, and at Prichard in Wayne County. In all of these areas of successful construction, the essential information for initial test drilling was obtained by detailed hydrogeologic work at the prospective sites. Most important was the determination of the maximum depth of fresh water, well spacing and pumping rates.
Subsurface Biological Activity in Relation to Ground‐Water Pollutiona
Authors: McNabb James F. , Dunlap William J. 
Published: July 2006

ABSTRACTBiological activity occurring in subsurface regions below the soil zone may be of considerable importance in determining the fate and effect of pollutants in ground water, but this possibility has received little previous attention. This paper comprises a discussion of subsurface biological activity in regard to ground‐water pollution as reflected by available literature references. The subsurface environment is discussed in terms of factors likely to be of greatest significance in regard to the development of biological systems, and previous investigations of subsurface microbial activity are reviewed. Available information indicates the presence in the upper continental crust of the earth of numerous regions, particularly those of sedimentary origin, which are probably suitable habitats for many microbial species. Previous investigations of subsurface microbial activity clearly show the presence of diverse microbial populations in many subsurface regions below the soil zone. Hence, microbial activity appears both possible and probable in most subsurface regions of importance in regard to ground water. Further elucidation of the extent and nature of microbial activity in subsurface regions is needed in developing methods for predicting the impact on ground‐water quality of pollutants released into the earth's crust.
Natural Soil Nitrate: The Cause of the Nitrate Contamination of Ground Water in Runnels County, Texasa
Authors: Kreitler Charles W. , Jones David C. 
Published: July 2006

ABSTRACTThe ground waters of Runnels County, Texas, are highly contaminated with nitrate. The average nitrate concentration of 230 water samples was 250 mg/I NO3.The natural variations of the stable nitrogen isotopes N14 and N15 identified natural soil nitrate as the predominant source. Nitrate from animal wastes was of minor importance. The δN15 range of natural soil nitrate was +2 to +8% whereas the δN15 range of animal waste nitrate was +10 to +20%‐ (Atmospheric nitrogen was used as a standard for mass spectrometric analysis. Experimental error for sample preparation and isotopic analysis was ±1 %.) More than 66 percent of the ground‐water nitrates analyzed were in the δN15 range of natural soil nitrates.Dryland farming since 1900 has caused the oxidation of the organic nitrogen in the soil to nitrate. Minimal fertilizer has been used because of the lack of suitable water for irrigation. During the period 1900‐1950, nitrate was leached below the root zone but not to the water table. Extensive terracing after the drought in the early 1950's has raised the water table approximately 6 meters and has leached the nitrate into the ground water. Tritium dates indicate that the ground water is less than 20 years old.
Earth Resistivity Surveys — A Method for Defining Ground‐Water Contaminationa
Authors: Stollar Robert L. , Roux Paul 
Published: July 2006

ABSTRACTAn important part of every investigation of ground‐water pollution is to locate and define the extent of the contaminated body of ground water. The usual method for accomplishing this is to install and sample numerous test wells, a costly and time‐consuming procedure. A much faster and less costly method, which has proven to give accurate results, is the earth resistivity survey. Because earth resistivity is inversely proportional to ground‐water conductivity, the location of ground water that has been contaminated by a relatively high concentration of conductive industrial wastes, for example, may be quickly and accurately traced.In order for the resistivity method to give useful results, resistivity contrasts must exist in the subsurface. For example, if the contaminant does not have a significantly greater conductivity than the natural ground water, or if the ground water is naturally highly conductive itself, a large enough resistivity contrast may not exist, and the method may not work. In addition, if depth to water is too great, the thickness of the unsaturated sediments can mask any contrasts between contaminated and natural ground water. The geologic environment must be relatively uniform so that the resistivity values and profiles can be compared with one another. At most industrial plant sites and landfills, these conditions are met. That is, the area of investigation is usually limited to a few hundred acres, where the geology and depth to water tend to be uniform.Four case histories of industrial and landfill sites are discussed in this paper. The areas underlain by the contaminated ground‐water bodies ranged from 25 to 100 acres. The depths to the contaminated water were relatively shallow, ranging from 5 to about 60 feet below land surface. In three of the cases, the results of the earth resistivity studies, which were verified by installing test wells in and around the area being investigated, proved to be remarkably accurate. In the fourth study, the conditions mentioned were not met, and the survey was unsuccessful.
Thirty‐Five Years of Continuous Discharge of Secondary Treated Effluent onto Sand Bedsa
Authors: Aulenbach Donald B. , Tofflemire T. James 
Published: July 2006

ABSTRACTThe Lake George Village sewage treatment plant has been discharging trickling filter effluent onto natural delta sand beds for a period of 35 years. The applied sewage apparently appears near the banks of West Brook approximately 600 m (2000 ft) from the lower sand beds. Wells have been placed between the recharge beds and the appearance of the seepage at West Brook. The quality of the water in the wells has been evaluated over the period of slightly over one year.The ground water appears to be aerobic at all times indicating that the oxygen demand of the applied effluent has been adequately reduced before it reaches the ground water. This should afford adequate and proper tertiary treatment for the applied effluent.The phosphorus concentration was significantly reduced at the first well downstream (ground water) approximately 150 m (500 ft) from the sand beds. The phosphorus in well 2 approximately 600 m (2000 ft) from the lower sand beds reached a high value of 150 μg/l during the late fall but was less than 100 μg/l during the rest of the year.Some of the nitrogen in the applied effluent was apparently oxidized to nitrate which was very little removed by the sand system. The highest nitrate concentration found was 14 mg N/l in well 3C during the Spring, whereas well 3A had almost consistently the lowest concentration of nitrate.
Ground‐Water Contamination in the Silurian Dolomite of Door County, Wisconsina
Authors: Sherrill M. G. 
Published: July 2006

ABSTRACTDoor County, a recreational and fruit‐growing area bordering Lake Michigan in northeastern Wisconsin, has had a long history of ground‐water contamination from surface and near‐surface sources. Contamination is most severe in late summer when the influx of tourists and fruit‐canning operations create additional wastes.Thin soil cover and well‐fractured dolomitic bedrock give easy entry to ground‐water contaminants throughout large parts of Door County. Many contaminants enter the dolomite by surface or near‐surface seepage. There is little attenuation of contamination concentrations in the well‐jointed dolomite, and contaminants may travel long distances underground in a relatively short time. The major source of ground‐water contamination is bacterial, from individual waste‐disposal systems, agricultural, industrial, and municipal sources. Contamination is in zones that originate from point sources and move in the direction of ground‐water flow, either naturally or as induced by pumping wells. The contaminated areas include only a small percentage of the total ground‐water system and are separated by large areas of ground water free of contamination. Tests based on indicator bacteria suggest that the periods of highest contamination potential occur during or immediately following rapid ground‐water recharge periods. Increasing the depth of casing and pressure grouting the casing into firm bedrock are two well‐construction procedures that reduce the contamination potential in wells.
Ground‐Water Recharge Rates from Thermometrya
Authors: Nightingale Harry I. 
Published: July 2006

ABSTRACTBasin artificial ground‐water recharge rate at the Leaky Acres Recharge Project in Fresno, California was evaluated by Fourier analysis of temperature variations of air, basin water and ground water. The weekly mean basin‐water temperature correlated well (r = 0.982) with weekly mean air temperature. Weekly mean temperature data of the air, basin water, and recharged ground water showed that the first harmonic curve was satisfactory for determining the times of minimum and maximum temperature when convective transfer of heat was considered.The lag time between maximum basin‐water temperature and maximum ground‐water temperature at a 16 m depth (52.5 ft), showed water moved at a thermal tracer velocity of 20.8 cm/day (0.68 ft/day). The corresponding infiltration rate measured by the falling‐head method in study area basins was 18.5 cm/day (0.61 ft/day). This and other reported studies indicate that under suitable conditions with simple field instrumentation ground‐water thermometry can be used to estimate the rate and direction of recharged water movement.
Upconing of the Salt‐Water–Fresh‐Water Interface Beneath a Pumping Well
Authors: Chandler R. L. , McWhorter D. B. 
Published: July 2006

ABSTRACTThe upconing of saline water in response to pumping from an overlying layer of fresh water is investigated by numerical integration of the governing differential equation. The transition zone between the fresh and saline water is idealized as an abrupt interface. Full consideration of the nonlinear boundary conditions on the water table and interface surfaces is included for steady flow toward partially penetrating pumping wells in both isotropic and anisotropic aquifers. There exists an optimum well penetration into the fresh‐water layer which permits maximum discharge without salt‐water entrainment. The optimum penetration increases as the vertical permeability is reduced relative to the horizontal permeability. The maximum well discharge obtainable without salt‐water entrainment is greater for aquifers with a reduced vertical permeability than for isotropic aquifers, a result that contrasts with previously published conclusions. Previous analyses which linearize the boundary condition on the interface overestimate the critical discharge.